JP2014189615A - Polyethylene for pipe and joint, and its molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide polyethylene for a pipe and a joint excellent in durability and having short crystallization time especially in applications for the pipe and a joint, capable of molding at high cycle and excellent in moldability and dimensional stability in both methods of an injection molding method and an extrusion molding method, and to provide a molded body thereof.SOLUTION: There is provided polyethylene for a pipe or a joint, satisfying following properties (i) to (iii). Property (i): high load melt flow rate (HLMFR (W), JIS K7210, temperature 190°C, load 21.60 kg) is 5 to 35 g/10 min. Property (ii): density is 0.945 to 0.960 g/cm. Property (iii): a peak top time in isothermal crystallization at 121.5°C, measured by a differential scanning calorimeter (DSC), is 360 sec. or less.

Description

  The present invention relates to polyethylene for pipes and joints and molded articles thereof. More specifically, in particular for pipes and joints, the crystallization time is short, and high cycle molding is possible in both injection molding and extrusion molding methods. In addition, the present invention relates to polyethylene for pipes and joints and a molded body thereof excellent in moldability, dimensional stability, pressure resistance and durability.

Polyethylene resin is excellent in molding processability and various physical properties, and is highly economical and adaptable to environmental problems. Therefore, it is used as a material in a very wide technical field and is used for a wide range of applications. One field of its use is the pipe field, and its use for gas pipes, water distribution pipes, etc. is increasing based on the track record of durability during earthquakes.
Resins currently used for gas pipes and water distribution pipes must satisfy excellent long-term durability such as PE80 (MRS: Minimum Required Strength = 8 MPa) and PE100 (MRS = 10 MPa) defined by ISO 9080 and ISO 12162. is there. It is also necessary to have extremely high performance hot internal pressure pipe creep performance as described in ISO 1167. In order to exert such performance, since the durability tends to be inferior when the fluidity is increased, polyethylene having a low fluidity or melt flow rate (hereinafter also referred to as “MFR”) is obtained even if productivity is sacrificed. I had to use it.
At present, for example, in the standard of polyethylene pipes for water distribution, in order to ensure durability, the pipe thickness design is set to SDR (Standard dimension ratio) = D / t = 11. However, in this case, in the case of a pipe having a large nominal diameter, the pipe thickness is also proportionally increased. For example, when the nominal diameter is 200, the thickness is 20 mm. Therefore, for reasons such as weight increase and economy, it is necessary to further improve MRS (Minimum Required Strength), which is the long-term hydrostatic strength of the polyethylene pipe material for water distribution, in order to reduce the pipe thickness.
In terms of pressure resistance, ductile cast iron pipes and the like that are superior in pressure resistance and weather resistance compared to polyethylene pipes are currently widely used as water distribution pipes that can be used even at high water pressures. Therefore, in order to use a polyethylene pipe as a substitute for a ductile cast iron pipe, it is necessary to improve pressure resistance, weather resistance, etc. in the polyethylene pipe.
In addition, recently, due to changes in the pipe laying construction method, even if the surface of the formed pipe is damaged, it has excellent long-term durability, that is, low-speed crack propagation property such as the notched pipe test specified in ISO 13479 ( A polyethylene resin excellent in Slow Crack Growth (SCG) has been demanded.

These polyethylene resins for pipes are produced by copolymerization of ethylene and α-olefin by multi-stage polymerization in the presence of a Philips catalyst or a Ziegler catalyst. However, a polyethylene resin using a Philips catalyst has a drawback in long-term durability, and PE100 The highly durable polyethylene resin for water distribution pipes that satisfies the above requirements is exclusively produced by the latter Ziegler catalyst.
Polyethylene resin for pipes obtained by copolymerization of ethylene and α-olefin by multi-stage polymerization using Ziegler catalyst has many prior arts, but satisfies the standards of PE100 and has SCG, rigidity, fluidity, homogeneity Although it is difficult to produce a polyethylene resin having excellent properties, various proposals have been made as follows.

Proposals for improving polyethylene resins for pipes that can be produced using Ziegler catalysts include, for example, pipe quality standards, such as internal pressure, without risk of pipe tearing or sagging problems during production. Can be used to produce large diameter thick pipes with mechanical performance and product homogeneity well matched to long-term resistance to resistance, high stress crack resistance, low temperature notched impact strength and high resistance to rapid crack growth In order to provide a polyethylene molding compound having a sufficiently high melt strength, a copolymer of 1-olefin having a total number of carbon atoms in the range of 4 to 10 as a comonomer and ethylene, and a first ethylene polymer A first ethylene polymer having a comonomer in a proportion of 0.2 to 5% by mass relative to the mass of (A) and a broad bimodal molecular mass distribution. Is a copolymer produced from 55 to 75% by weight of a mer (A), an ethylene structural unit, and a 1-olefin having 4 to 10 carbon atoms, and is different from the first ethylene polymer (A). A polymer molding compound produced from 25 to 45% by weight of a second ethylene polymer (B) having a bimodal molecular mass distribution has been proposed (see Patent Document 1).
However, even the compound described in Patent Document 1 does not satisfy the requirements for higher durability and fluidity. In addition, the crystallization time of a material that can shorten the crystallization time, shorten the manufacturing cycle (high cycle), and improve the dimensional stability is not described and is not clear.

Also, a polyethylene resin for pipes produced in the presence of a metallocene catalyst has been proposed.
For example, for the purpose of providing an improved polyethylene pipe resin, a first polyethylene fraction of 35 to 49% by weight and a low molecular weight of 51 to 65% by weight produced substantially with a metallocene catalyst. A polyethylene resin comprising a second polyethylene fraction, wherein the first polyethylene fraction comprises a linear low density polyethylene having a density of up to 0.928 g / cm ³ and an HLMI of less than 0.6 g / 10 min. And the second polyethylene fraction comprises high density polyethylene having a density of at least 0.969 g / cm ³ and MI ₂ higher than 100 g / 10 min, and the polyethylene resin has a density higher than 0.951 g / cm ^3. And polyethylene pipe resins having an HLMI of 1 to 100 g / 10 min have been proposed (special See Permissible Document 2).
However, even the polyethylene resin described in Patent Document 2 does not satisfy the requirements for higher long-term durability or fluidity. Furthermore, the crystallization time of a material that can shorten the crystallization time, shorten the manufacturing cycle (high cycle), and improve the dimensional stability is not described and is not clear.

In addition, the present applicant has previously proposed a polyethylene resin for pipes that is excellent in the balance between molding processability and rigidity and the mechanical properties of SCG and that is excellent in homogeneity (see Patent Document 3).
That is, in the field of pipes, in particular, pipes for water distribution, not only satisfying PE100, but also a polyethylene resin excellent in SCG, sufficient fluidity, homogeneity, etc., and a method for producing the same, and pipes and joints using the resin For the purpose of providing: (a) high load melt flow rate (HLMFR, HLa) 5-20 g / 10 min, (b) density (Da) 0.945-0.965 g / cm ³ , (c) α-olefin content (Ca) satisfies 0.05 to 1.5 mol%, (d) Notched Lander method-ESCR failure time (T), and HLa and Ca satisfy a specific formula A polyethylene resin for pipes was proposed.
The polyethylene resin is preferably a polyethylene resin using a Ziegler catalyst, which defines HLMFR, density and α-olefin content, and has a configuration specified by a notched Lander method-ESCR, more preferably It is also characterized by combining a specific α-olefin copolymer in a resin and using a specific multistage polymerization method, and in particular, it satisfies PE100 in a pipe molded product and enables a very excellent SCG. It is.
However, due to demands for higher performance or productivity, further improvements in durability, fluidity, and reduction in crystallization time are desired and not sufficient.

In view of these problems, in recent years, various multimodal polyethylenes have been proposed.
For example, based on polyethylene and having a better combination of environmental stress crack resistance, mechanical strength, and processing behavior, especially over time, while retaining good processability with respect to its use as a pipe raw material. For the purpose of providing a molding composition, 45 to 55% by weight of low molecular weight ethylene homopolymer A, 20 to 40% by weight of ethylene and 4 to 8 carbon atoms, based on the total weight of the molding composition A polyethylene molding composition for producing pipes having a multimodal molecular weight distribution is proposed, comprising a high molecular weight copolymer B comprising other olefins having a weight ratio of 15 to 30% by weight and an ultrahigh molecular weight ethylene copolymer C. (See Patent Document 4).
Also, sag resistance, moldability, for the purpose of providing a resin having a stress cracking resistance, composed of ethylene and 0.5 to 5 wt% of 4 to 8 carbon atoms α- olefin, a melt index MI ₅ is 0. 15 to 0.5 g / 10 min, 100 rad / s, dynamic complex viscosity (η ₁₀₀ ) at 190 ° C. is less than 2500 Pa · s, η ₁₀₀ and η _0.01 are in a relationship of η _0.01 > 115000 + 30 · η ₁₀₀ And a composition in which the value of a notched pipe test at a temperature of 80 ° C., a pipe of 110 mm SDR 11, and a pressure of 9.2 bar is more than 1000 hours in accordance with ISO 13479: 1997 is proposed (see Patent Document 5) ).
Further, for the purpose of satisfying the requirements of excellent balance such as moldability, impact strength, elastic modulus and high-speed crack propagation resistance, PENT (Pennsylvania Notch Test) is larger than 5000 hours, preferably larger than 8000 hours. Component (A) and a high molecular weight component (B), a density of 0.945 to 0.949 g / cm ³ , an MFR ₅ of 0.2 to 0.4 g / 10 min, and a comonomer content of 2% by weight. A pipe made of a polyethylene composition having a larger SHI (2.7 / 210) (shear viscosity index) of 55 to 100 is provided (see Patent Document 6).
However, even in the polyethylene resins described in these documents, the crystallization time of the material that can shorten the crystallization time, shorten the manufacturing cycle (high cycle), and improve the dimensional stability is not described and is not clear. .

  As described above, the polyethylene resin for pipes and joints and the molded products thereof have a short crystallization time while maintaining high quality standards for pipes in terms of pressure resistance and long-term durability. In both of the molding methods, it is possible to perform molding at a high cycle, and in addition, no product having excellent moldability and dimensional stability has been obtained.

JP-T-2004-50023 Publication Japanese translation of PCT publication No. 2004-512410 JP 2007-002235 A Special table 2009-508975 WO2007 / 028552A1 WO2008 / 131817A1

  In view of the above-mentioned problems of the prior art, the object of the present invention is to shorten the crystallization time, particularly in pipe and joint applications, and enables high-cycle molding in both the injection molding method and the extrusion molding method. Furthermore, it is providing the polyethylene for pipes and joints, and its molded object excellent in moldability, dimensional stability, pressure resistance, and durability.

  As a result of intensive studies in order to solve the above problems, the present inventor has found that high load melt flow rate (JIS K7210, temperature 190 ° C., load 21.60 kg, hereinafter also referred to as “HLMFR”), density and differential. The peak top time in isothermal crystallization at 121.5 ° C. measured with a scanning calorimeter (DSC) is both in a specific range, and the crystallization time is short especially in pipes and fittings, and injection molding. In both the extrusion method and the extrusion molding method, it is possible to obtain a polyethylene for pipes and joints and a molded article thereof that can be molded in a high cycle and is excellent in moldability, dimensional stability, pressure resistance and durability. As a result, the present invention has been completed.

That is, according to the first aspect of the present invention, there is provided a polyethylene for pipes and joints characterized by satisfying the following characteristics (i) to (iii).
Characteristic (i): High load melt flow rate (HLMFR (W) JIS K7210, temperature 190 ° C., load 21.60 kg) is 5 to 35 g / 10 min.
Characteristic (ii): The density is 0.945 to 0.960 g / cm ³ .
Characteristic (iii): The peak top time in isothermal crystallization at 121.5 ° C. measured by a differential scanning calorimeter (DSC) is 360 seconds or less.

According to the second invention of the present invention, in the first invention, the high load melt flow rate (HLMFR (II), JIS K7210, temperature 190 is used with respect to 50 to 80% by weight of the ethylene-based polymer (I). And 20 to 50% by weight of an ethylene polymer (II) having a density of 0.01 to 0.5 g / 10 min and a density of 0.915 to 0.930 g / cm ^3. A polyethylene for pipes and joints is provided.

  According to the third invention of the present invention, in the second invention, the ethylene polymer (II) is polymerized using a metallocene catalyst having a cyclopentadienyl ring and a heterocyclic aromatic group. A polyethylene for pipes and joints is provided.

According to a fourth invention of the present invention, in any one of the first to third inventions, the density is 0.950 to 0.960 g / cm ³ and 121 measured by a differential scanning calorimeter (DSC). Provided is a polyethylene for pipes and joints, characterized in that the peak top time in isothermal crystallization at 5 ° C. is 180 seconds or shorter and the following properties (iv) and (v) are satisfied.
Characteristic (iv): The rupture time in a full notch creep test (measured at 80 ° C. and 5 MPa) is 300 hours or more.
Characteristic (v): Flexural modulus (23 ° C.) is 1100 MPa or more.

According to a fifth invention of the present invention, in any one of the second to fourth inventions, the ethylene polymer (II) is a high-load melt flow rate (HLMFR (II), JIS K7210, temperature 190 ° C., load 21.60 kg) is 0.05 to 0.5 g / 10 min, and the weight average molecular weight (Mw (Mw (MPC)) is measured by HLMFR (II) (unit: g / 10 min) and gel permeation chromatography (GPC). II)) satisfies the following relationship (1): a polyethylene for pipes and joints is provided.
log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +6.0 (1)

According to a sixth invention of the present invention, in any one of the first to third inventions, the high load melt flow rate (HLMFR (W), JIS K7210, temperature 190 ° C., load 21.60 kg) is more than 15 to 35 g. / 10 minutes, the density is 0.945 to 0.954 g / cm ³ , the rupture time in the full notch creep test (measured at 80 ° C. and 5 MPa) is 300 hours or more, and the differential scanning calorimeter (DSC) A polyethylene for pipes and joints is provided, wherein the peak top time in isothermal crystallization at 121.5 ° C. measured is 180 seconds or less and the flexural modulus (23 ° C.) is 950 MPa or more. .

According to the seventh aspect of the present invention, in the sixth aspect, the ethylene polymer (I) is polymerized using 55 to 64% by weight using a metallocene catalyst containing Ti, Zr or Hf. , High load melt flow rate (HLMFR (II), JIS K7210, temperature 190 ° C., load 21.60 kg) is 0.1 to 0.5 g / 10 min and density is 0.915 to 0.930 g / cm ^3. There is provided a polyethylene for pipes and joints characterized by containing 36 to 45% by weight of an ethylene polymer (II).

According to the eighth invention of the present invention, in any one of the first to third inventions, the high load melt flow rate (HLMFR (W), JIS K7210, temperature 190 ° C., load 21.60 kg) is 7 to 15 g / 10 min, density is 0.945 to 0.954 g / cm ³ , rupture time in full notch creep test (measured at 80 ° C., 5 MPa) is 500 hours or more, and differential scanning calorimeter (DSC) There is provided a polyethylene for pipes and joints, characterized in that the peak top time in isothermal crystallization at 121.5 ° C. measured at 121.5 ° C. is 180 seconds or less and the flexural modulus (23 ° C.) is 950 MPa or more The

According to the ninth aspect of the present invention, in the sixth aspect, the high-load melt flow rate (HLMFR (II), JIS K7210, temperature 190 ° C., relative to 50 to 60% by weight of the ethylene polymer (I). Load 21.60 kg) is 0.05 to 0.5 g / 10 min, density is 0.915 to 0.930 g / cm ³ , HLMFR (II) (unit: g / 10 min) and gel permeation The weight average molecular weight (Mw (II)) measured by chromatography (GPC) contains 40 to 50% by weight of an ethylene polymer (II) satisfying the relationship of the following (1). Polyethylene for pipes and fittings is provided.
log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +6.0 (1)

According to a tenth aspect of the present invention, in any one of the first to third aspects, the high load melt flow rate (HLMFR (W), JIS K7210, temperature 190 ° C., load 21.60 kg) is 5 to 20 g / 10 minutes, the density is over 0.954 to 0.960 g / cm ³ , the rupture time in the full notch creep test (measured at 80 ° C. and 5 MPa) is 300 hours or more, and a differential scanning calorimeter (DSC) is used. A pipe and joint polyethylene characterized in that the peak top time in isothermal crystallization at 121.5 ° C. measured in the above is 180 seconds or less and further satisfies the following property (vi):
Characteristic (vi): The tensile yield stress is 27 MPa or more.

According to the eleventh aspect of the present invention, in the tenth aspect, 60 to 65% by weight of the ethylene polymer (I) is polymerized using a metallocene-based catalyst containing Ti, Zr or Hf. Road melt flow rate (HLMFR (II), JIS K7210, temperature 190 ° C., load 21.60 kg) is 0.01 to 0.5 g / 10 min, and density is 0.915 to 0.930 g / cm ³ . HLMFR (II) (unit: g / 10 min) and an ethylene polymer (Mw (II)) having a weight average molecular weight (Mw (II)) measured by gel permeation chromatography (GPC) (1) II) Polyethylene for pipes and joints characterized by containing 35 to 40% by weight is provided.
log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +6.0 (1)

  According to a twelfth aspect of the present invention, there is provided a molded body comprising the pipe and the joint polyethylene of any one of the first to eleventh aspects.

  According to a thirteenth aspect of the present invention, in the twelfth aspect, there is provided a molded body that is a pipe or a joint.

  As described above, the present invention relates to polyethylene for pipes and joints, and preferred embodiments thereof include the following.

(1) In the seventh invention, for pipes and joints, comprising 38 to 40% by weight of ethylene polymer (II) with respect to 60 to 62% by weight of ethylene polymer (I) polyethylene.
(2) In the seventh invention, the ethylene polymer (I) has a melt flow rate (MFR (I), JIS K7210, temperature 190 ° C., load 2.16 kg) of 50 to 200 g / 10 min, Is a polyethylene for pipes and joints, characterized in that it is 0.955 to 0.975 g / cm ³ .
(3) In the seventh invention, the ethylene polymer (I) has a melt flow rate (MFR (I), JIS K7210, temperature 190 ° C., load 2.16 kg) of 80 to 150 g / 10 min, Is a polyethylene for pipes and joints, characterized in that it is 0.966 to 0.973 g / cm ³ .
(4) In the seventh invention, polyethylene for pipes and joints, wherein the ethylene polymer (I) is an ethylene polymer composition polymerized using a Ziegler catalyst.
(5) In the seventh invention, the ethylene polymer (II) has an HLMFR (II) of 0.1 to 0.4 g / 10 min and a density of 0.915 to 0.925 g / cm ³ . , HLMFR (II) (unit: g / 10 min) and weight average molecular weight (Mw (II)) measured by gel permeation chromatography (GPC) satisfy the following relationship (1): Polyethylene for pipes and fittings.
log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +6.0 (1)
(6) In the seventh invention, a polyethylene for pipes and joints characterized in that the ethylene polymer (II) is polymerized using a metallocene catalyst having a cyclopentadienyl ring and a fluorenyl ring.

(7) In the ninth invention, for pipes and joints, comprising 45 to 50% by weight of ethylene polymer (II) with respect to 50 to 55% by weight of ethylene polymer (I) polyethylene.
(8) In the ninth invention, the ethylene polymer (I) has a melt flow rate (MFR (I), JIS K7210, temperature 190 ° C., load 2.16 kg) of 50 to 200 g / 10 minutes, Is a polyethylene for pipes and joints, characterized in that it is 0.955 to 0.975 g / cm ³ .
(9) In the ninth invention, the ethylene polymer (I) has a melt flow rate (MFR (I), JIS K7210, temperature 190 ° C., load 2.16 kg) of 80 to 150 g / 10 min, Is a polyethylene for pipes and joints, characterized in that it is 0.966 to 0.973 g / cm ³ .
(10) The polyethylene for pipes and joints according to the ninth invention, wherein the ethylene polymer (I) is an ethylene polymer composition polymerized using a Ziegler catalyst.
(11) In the ninth invention, polyethylene for pipes and joints, wherein the ethylene polymer (II) is polymerized using a metallocene catalyst having a cyclopentadienyl ring and a fluorenyl ring.

(12) In the eleventh aspect of the invention, for pipes and joints characterized by containing 37 to 40% by weight of ethylene polymer (II) with respect to 60 to 63% by weight of ethylene polymer (I). polyethylene.
(13) In the eleventh invention, the ethylene polymer (I) has a melt flow rate (MFR (I), JIS K7210, temperature 190 ° C., load 2.16 kg) of 50 to 200 g / 10 minutes, Is a polyethylene for pipes and joints, characterized in that it is 0.960 to 0.975 g / cm ³ .
(14) In the eleventh invention, the ethylene polymer (I) has a melt flow rate (MFR (I), JIS K7210, temperature 190 ° C., load 2.16 kg) of 80 to 150 g / 10 min, Is a polyethylene for pipes and joints, characterized in that it is 0.966 to 0.973 g / cm ³ .
(15) In the eleventh invention, the ethylene polymer (I) is an ethylene polymer composition polymerized using a Ziegler catalyst, and a polyethylene for pipes and joints.
(16) In the eleventh invention, the ethylene polymer (II) has an HLMFR (II) of 0.05 to 0.2 g / 10 min and a density of 0.920 to 0.925 g / cm ³ . A polyethylene for pipes and joints characterized by the above.
(17) In the eleventh invention, the ethylene polymer (II) is polymerized using a metallocene catalyst having a cyclopentadienyl ring and a fluorenyl ring, and a polyethylene for pipes and joints.
(18) A thin polyethylene pipe characterized by using the pipe and the polyethylene for joints according to the tenth or eleventh invention.

  The polyethylene for pipes and joints of the present invention has a short crystallization time. For example, in injection molding, the time for taking out a molded product is shortened, high cycle is possible, productivity is improved, and a thick product is obtained. However, there is an effect that post-shrinkage hardly occurs and dimensional stability is good. Furthermore, for example, in extrusion molding, the cooling time is shortened due to the high crystallization speed, enabling the production cycle to be increased. At the same time, the crystallization speed of the pipe extruded in the molten state is high, so that the pipe generated during molding There is an effect that resistance to surface scratches is improved and the pipe surface appearance is improved. Moreover, the molded product using the polyethylene for pipes and joints of the present invention has performance exceeding the quality standards for pipes such as durability and can be formed at high speed, and is economically advantageous. And there is an effect that it can be suitably used as a joint or the like.

  Moreover, in one of the aspects of this invention, in addition to the said performance, there exists an effect that it is excellent in a bending elastic modulus. Therefore, the polyethylene for pipes and joints of the present invention is excellent in pressure resistance, and can be used under high pressure, or the product can be made thinner and lighter.

  Moreover, in another aspect of this invention, in addition to the said performance, there exists an effect that it is excellent in fluidity | liquidity. Therefore, it fully meets the quality standards for pipes, for example, long-term durability under conditions of internal pressure, high resistance to SCG under stress concentration due to notch shape, etc., and greatly improves them compared to conventional PE100 materials As a result, it has the effect of being capable of high-speed molding because of its high fluidity and high crystallization speed. Therefore, it has the effect of exhibiting excellent productivity in both injection molding and extrusion molding methods as well as performance exceeding conventional PE100. Specifically, for example, in injection molding, the fluidity is high and the crystallization time is short, so the time for taking out the molded product is shortened, high cycle is possible, productivity is improved, and a thick product is used. Even if it exists, there exists an effect that post-shrinkage does not arise easily and dimensional stability is good. Furthermore, for example, in extrusion molding, the motor load is reduced due to high fluidity, so that the screw rotation speed can be further increased, and the cooling time is shortened due to the high crystallization speed, which can increase the production cycle. At the same time, since the crystallization speed of the pipe extruded in a molten state is high, there is an effect that resistance to pipe surface scratches generated during molding is improved and the pipe surface appearance is improved.

  Moreover, in another aspect of this invention, in addition to the said performance, there exists an effect that it is excellent in long-term durability. Therefore, it fully meets the quality standards for pipes, such as long-term resistance to internal pressure, high stress crack resistance, low temperature notched impact strength and high resistance to rapid crack growth, and in particular, long-term durability is the traditional PE100. Compared to the material, it is greatly improved, and since the crystallization speed is high, there is an effect that high-speed molding is possible. Therefore, it has performance superior to that of conventional PE100, exhibits excellent productivity in both the injection molding and extrusion molding methods, and controls the blending ratio, molecular weight, and molecular weight distribution of each component. In order to suppress aggregation of the molecular weight component (polymer gel), there is an effect that there is no appearance defect due to the high molecular weight gel. The above "long-term durability" refers to excellent environmental stress crack resistance, hot internal pressure creep resistance of the pipe or low-speed crack extension characteristics, etc., and the polyethylene resin composition for pipes and joints of the present invention is In particular, the value by a full notch creep test (FNCT) is high, and there is an effect that the environmental stress crack resistance is extremely excellent. In addition, the polymer gel, which occurs in the shape of a lump and causes poor appearance, has the effect of suppressing the aggregation of the high molecular weight components and improving the pipe surface appearance by uniformly mixing the components constituting the polyethylene. is there. Furthermore, the molded article using the polyethylene for pipes and joints of the present invention has performance exceeding the quality standard for pipes, in particular, the value by FNCT which is slow crack growth is high, and extremely long-term durability is high. High-speed molding is possible, and it can be suitably used as an economically advantageous pipe for water distribution and a joint.

  Moreover, in another aspect of this invention, in addition to the said performance, it is excellent in pressure resistance, and there exists an effect that it can be set as a thin-walled polyethylene pipe. Therefore, it fully meets the quality standards for pipes, for example, long-term durability under conditions of internal pressure, high resistance to SCG under stress concentration due to notch shape, etc., and greatly improves them compared to conventional PE100 materials As a result, the high-speed molding is possible because the crystallization speed is high. Therefore, in particular, with respect to the durability, the performance is far superior to that of the conventional PE 100, and excellent productivity is exhibited in both the injection molding and the extrusion molding methods. In addition, since the molded product using the polyethylene for pipes and joints of the present invention has performance far exceeding the conventional quality standards for pipes, the thickness of the pipe is reduced, the weight of the pipe is reduced, and the service life is reduced. There is an effect that improvement, expansion of application locations, and the like are possible. And since the thin-walled polyethylene pipe of the present invention has excellent performance and productivity as described above, it is possible to reduce the weight of the pipe, improve the service life, expand the application area, improve the earthquake resistance, etc. There is an effect that it is economically advantageous.

  Therefore, the polyethylene for pipes and joints of the present invention is suitable for gas pipes, water distribution pipes and their joints, and particularly suitable for polyethylene pipes for water distribution and joints thereof.

The polyethylene for pipes and joints of the present invention is characterized by satisfying specific physical property requirements. Preferably, the ethylene polymer (II) having a specific property is added to the ethylene polymer (I). It is characterized by blending a specific amount.
Hereinafter, the present invention will be described in detail for each item.

1. Properties of polyethylene for pipes and joints The polyethylene for pipes and joints of the present invention (hereinafter also referred to as “polyethylene of the present invention”) is characterized by satisfying the following properties (i) to (iii).
Characteristic (i): High load melt flow rate (HLMFR (W), JIS K7210, temperature 190 ° C., load 21.60 kg) is 5 to 35 g / 10 min.
Characteristic (ii): The density is 0.945 to 0.960 g / cm ³ .
Characteristic (iii): The peak top time in isothermal crystallization at 121.5 ° C. measured by a differential scanning calorimeter (DSC) is 360 seconds or less.

(1) Characteristic (i): High load melt flow rate In the polyethylene of the present invention, the high load melt flow rate (HLMFR (W), JIS K7210, temperature 190 ° C., load 21.60 kg) of characteristic (i) is 5 It is -35g / 10min, Preferably it is 7-20g / 10min, More preferably, it is 9-18g / 10min.
When HLMFR (W) is less than 5 g / 10 min, the molecular weight increases, and the moldability may not be ensured due to a decrease in fluidity. On the other hand, if it is larger than 35 g / 10 minutes, long-term durability, particularly SCG using FNCT as an index, may be lowered.

In this specification, the high load melt flow rate (also referred to as “HLMFR”) and the melt flow rate (also referred to as “MFR”) are values measured according to JIS K7210.
MFR and HLMFR can be adjusted by the ethylene polymerization temperature, the use of a chain transfer agent, or the like in the production of polyethylene, and a desired product can be obtained. That is, for example, MFR and HLMFR can be increased as a result of decreasing the molecular weight by increasing the polymerization temperature of ethylene and α-olefin, and MFR is increased as a result of increasing the molecular weight by decreasing the polymerization temperature. And HLMFR can be reduced. In addition, in the copolymerization reaction of ethylene and α-olefin, MFR and HLMFR can be increased as a result of decreasing the molecular weight by increasing the amount of coexisting hydrogen (amount of chain transfer agent). By reducing the amount (chain transfer agent amount), MFR and HLMFR can be reduced as a result of increasing the molecular weight.

(2) Characteristic (ii): Density In the polyethylene of the present invention, the density of characteristic (ii) is 0.945 to 0.960 g / cm ³ . Preferably it is 0.948-0.958 g / cm < ³ >, More preferably, it is 0.953-0.957 g / cm < ³ >. If the density is less than 0.945 g / cm ³ , the flexural modulus decreases, and as a result, the rigidity of the material is insufficient and the pressure resistance may be decreased. On the other hand, when the density exceeds 0.960 g / cm ³ , long-term durability, particularly SCG using FNCT as an index may be lowered.

In the present specification, the density of polyethylene, ethylene polymer (I) and ethylene polymer (II), which will be described later, is a value measured according to JIS K6922-1, 2: 1997. .
The desired density can be obtained by changing the density depending on, for example, the type and amount of the comonomer copolymerized with ethylene.

(3) Characteristic (iii): Crystallization time Further, in the polyethylene of the present invention, the peak top time in isothermal crystallization at 121.5 ° C. measured by the differential scanning calorimeter (DSC) of characteristic (iii) is 360 seconds or less. Preferably it is 300 seconds or less, More preferably, it is 180 seconds or less. The lower limit is 60 seconds or more because the polymer design must satisfy each characteristic in the polyethylene of the present invention. When this value exceeds 360 seconds, the crystallization time becomes longer, the molding speed is delayed, and the molding cycle may be lengthened.
This value can be adjusted by the density and molecular weight of polyethylene. For example, when the polyethylene is composed of an ethylene polymer (I) and an ethylene polymer (II), the density, molecular weight and blending amount of the ethylene polymer (II) can be adjusted.
Outside the above range, for example, when the polyethylene is composed of an ethylene polymer (I) and an ethylene polymer (II), the HLMFR of the ethylene polymer (II) is high, the density is low, and the blending amount is small The peak top time in isothermal crystallization at 121.5 ° C. measured with a differential scanning calorimeter (DSC) of polyethylene exceeds 360 seconds. In addition, outside this range, similarly, for example, when the polyethylene is composed of an ethylene polymer (I) and an ethylene polymer (II), the HLMFR of the ethylene polymer (II) is low, the density is high, If the amount is too large, the rigidity, moldability, long-term durability, and other requirements may not be satisfied.

  In the present specification, the peak top time in isothermal crystallization at 121.5 ° C. measured by a differential scanning calorimeter (DSC) of characteristic (iii) is, for example, DSC-7 manufactured by Perkin Elmer With a differential scanning calorimeter (DSC), the sample was allowed to stand at 190 ° C. for 5 minutes, then cooled to 121.5 ° C. at a rate of 120 ° C./minute, held, and crystallized at an isothermal temperature of 121.5 ° C. This is a value measured by detecting the peak top when the conversion is completed.

Furthermore, the polyethylene of the present invention preferably satisfies the following characteristics (iv) to (vi).
(4) Characteristic (iv): Breaking time in full-notch creep test In the polyethylene of the present invention, the breaking time in the full-notch creep test of characteristic (iv) (hereinafter also referred to as “FNCT”, measured at 80 ° C. and 5 MPa) is 300 It is preferable that it is more than time. More preferably, it is 400 hours or more, Most preferably, it is 500 hours or more.
If the above time is less than 300 hours, the durability of the molded product may be inferior.
In this specification, the rupture time in FNCT (measured at 80 ° C. and 5 MPa) is 80 ° C. and 5 MPa in accordance with the all-around notch tensile creep test in Appendix 1 of JIS K6774 (1995) “Polyethylene pipe for gas”. This is the value measured at. The test piece was prepared under the conditions shown in Table 2 of JIS K6922-2 (1997) “Plastics—Polyethylene (PE) molding and extrusion materials—Part 2: How to make test pieces and various properties”. It is cut out from a compression-molded sheet at 6 mm, and has a notch on the entire periphery (test piece thickness 6 mm, notch depth 1 mm entire periphery).
The test solution is not water but a 1% aqueous solution of sodium alkyl sulfate.
The rupture time in FNCT (measured at 80 ° C. and 5 MPa) can be generally increased, for example, by decreasing the density of the ethylene-based polymer (II) constituting polyethylene and decreasing HLMFR (II). it can.

(5) Characteristic (v): Flexural modulus In the polyethylene of the present invention, the flexural modulus of the characteristic (v) is preferably 950 MPa or more. More preferably, it is 1100 MPa or more, particularly preferably 1150 MPa or more, and still more preferably 1200 MPa or more. When the flexural modulus is less than 950 MPa, the flexural modulus decreases, resulting in insufficient material rigidity, which may reduce pressure resistance. Although the upper limit of a bending elastic modulus is not specifically limited, Usually, it is 1300 MPa or less.
Here, the flexural modulus is a value measured by cutting out a 10 mm × 80 × 4 mmt test piece from a 4 mm thick molded sheet prepared by compression molding according to JIS K6922-2.
The flexural modulus can be adjusted by increasing or decreasing the density of polyethylene, and the flexural modulus can be increased by increasing the density.

(6) Characteristic (vi): Tensile yield stress In the polyethylene of the present invention, the tensile yield stress of the characteristic (vi) is preferably 27 MPa or more. When this value is 27 MPa or less, the pressure resistance is insufficient when used in an environment with high pressure, or when the thickness of the pipe is reduced, and there is a risk of ductile fracture and rupture.
This value can be adjusted by the density of polyethylene. For example, when the polyethylene is composed of the ethylene polymer (I) and the ethylene polymer (II) described below, the density and the blending amount of the ethylene polymer (I) and the ethylene polymer (II) Adjustment is possible.
In addition, in this specification, the tensile yield stress of the characteristic (v) is a value measured in accordance with JIS K7161, and the test piece is a thickness of 4 mm created under the conditions of JIS K6922-2 (1997) Table 2. It is a value cut out from a compression molded sheet into a 1B multipurpose test piece shape and measured at a tensile speed of 50 mm / min in a measurement environment of 23 ° C.
If the tensile yield stress is 27 or more, for example, assuming that the MRS is about 12.5 MPa, the pipe thickness design can be reduced by about 18% compared to the PE100 material with an MRS of about 10 MPa. It is done.

The polyethylene for pipes and joints of the present invention satisfies the above characteristics and is particularly suitable for pipe and joint applications.
For example, in the case of polyethylene pipes for water distribution and joints thereof, it is desired to use the same materials as polyethylene pipes (pipe) and joints according to requests for various standards. Due to the above properties, the polyethylene for pipes and joints of the present invention sufficiently meets the quality standards for pipes, for example, long-term durability under internal pressure, and high resistance to SCG due to stress concentration due to notch shape. In addition, they have significantly improved performance compared to the conventional PE100 material, and have physical properties such as durability required for pipes and joints, and in particular, high fluidity and short crystallization time. In both the injection molding and extrusion molding methods, excellent productivity is exhibited.
Specifically, in injection molding, the flowability is high and the crystallization time is short, so the time for taking out the molded product is shortened, high cycle is possible and productivity is improved. Further, there is an effect that post-shrinkage hardly occurs and dimensional stability is good. Furthermore, in extrusion molding, the high fluidity reduces the motor load, and the high crystallization speed shortens the cooling time, enabling the production cycle to be increased, and at the same time the pipe product extruded in the molten state. Since the crystallization speed is high, there is an effect that resistance to pipe surface scratches generated during molding is improved and the pipe surface appearance is improved.
That is, the polyethylene for pipes and joints of the present invention has the above-mentioned properties of high fluidity and a short crystallization time, and thus has an economically effective point particularly in both injection molding and extrusion molding. The resin composition is suitable for pipes and joints.
Furthermore, the molded product using the polyethylene for pipes and joints of the present invention is suitable as a polyethylene pipe and joint because it has a performance exceeding that of conventional products in the quality standards for pipes.

As a component of the polyethylene for pipes and joints of the present invention, any polyethylene that satisfies the characteristics of the present invention can be used without limitation.
In the present invention, it is preferable to blend a specific amount of the ethylene polymer (II) having specific properties because the polyethylene of the present invention can be easily adjusted and becomes a preferable polyethylene for pipes and joints. Furthermore, it is preferable to blend a specific amount of ethylene polymer (II) having specific properties polymerized with a metallocene catalyst.

2. Ethylene polymer (II)
Since the polyethylene for pipes and joints of the present invention is easy to adjust the polyethylene of the present invention and becomes a preferable polyethylene for pipes and joints, high load melt flow rate (HLMFR (II), JIS K7210, temperature 190 ° C., load 21 .60 kg) is 0.01 to 0.5 g / 10 min, and 20 to 50% by weight of an ethylene polymer (II) having a density of 0.915 to 0.930 g / cm ³ is contained. It is preferable.

  The HLMFR of the ethylene polymer (II) is 0.01 g / 10 min or more and 0.5 g / 10 min or less, preferably 0.1 to 0.4 g / 10 min, more preferably 0.2 to 0.3 g. / 10 minutes. If this HLMFR (II) is less than 0.01 g / 10 minutes, in the final polyethylene, HLMFR (W) cannot be achieved within the specified range, and the fluidity may be lowered. On the other hand, when the HLMFR (II) exceeds 0.5 g / 10 min, the long-term durability, particularly SCG with FNCT as an index, is decreased in the final polyethylene, and the crystallization rate is decreased. The isothermal crystallization time at 121.5 ° C., which can be measured by the method, exceeds 360 seconds, and as a result, the molding cycle may be lowered.

The density of the ethylene-based polymer (II) is 0.915 to 0.930 g / cm ³ , preferably 0.915 to 0.925 g / cm ³ , more preferably 0.920 to 0.925 g / cm ^3. It is. If the density is less than 0.915 g / cm ³ , the density range in the final polyethylene cannot be achieved, and the flexural modulus decreases, resulting in insufficient rigidity of the material, which may reduce pressure resistance. On the other hand, when the density exceeds 0.930 g / cm ³ , the long-term durability of the final polyethylene, particularly SCG using FNCT as an index may be lowered.

  The ethylene polymer (II) satisfying this relationship has a long-chain branched structure, can be used with other resins, can increase the crystallization rate very effectively, and has added a so-called crystal nucleating agent. The same effect can be exhibited, the crystallization time can be shortened, high speed molding and high cycle can be achieved as polyethylene for pipes and joints, and durability can be improved.

In conventional polyethylene, methods such as adding a substance that acts as a crystal nucleating agent have been attempted to increase the crystallization speed. As a result of examining polyethylene that sufficiently improves both physical properties such as Polyethylene having specific values for time and flexural modulus (23 ° C.) can sufficiently improve the crystallization speed while maintaining excellent physical properties such as mechanical strength, thereby improving the molding speed. It is thought that it will be possible.
In particular, by using the ethylene polymer (II) according to the present invention together with, for example, the ethylene polymer (I), all of the above characteristics are satisfied, while maintaining the physical properties such as excellent mechanical strength, The forming speed can be sufficiently improved, and the forming speed can be improved.

  Preferably, the ethylene-based polymer (II) uses the following formula (1), more preferably the formula (2), particularly preferably the one satisfying the formula (3). This is a preferable polyethylene for pipes and joints that exhibits an effect and has a sufficiently improved crystallization rate.

log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +6.0 Formula (1)
log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +5.9 Formula (2)
log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +5.8 Formula (3)

  However, HLMFR (II) is a high load melt flow rate (unit: g / 10 min) at a temperature of 190 ° C. and a load of 21.6 Kg, and Mw (II) was measured by gel permeation chromatography (GPC). Weight average molecular weight.

Here, the technical meaning of the above formula (1) indicates that the fluidity is low in proportion to the weight average molecular weight, that is, the HLMFR (II) is small, which means that this ethylene polymer It shows that (II) has a long-chain branching, and that it is an ethylene polymer having a long-chain branching structure showing a specific HLMFR (II) with respect to a predetermined Mw (II).
In the formulas (1) to (3), the value of the intercept (“6.0” in the case of the formula (1)) is an index indicating the development of the long-chain branched structure. That the relational expression of HLMFR (II) is established indicates that the structure has a more developed long chain branching structure. If the development of the long chain branching structure is insufficient, the crystal nucleus material effect may be weakened and the crystallization rate may not be sufficiently improved.
In the technical field to which the present invention pertains, various methods are known for measuring an ethylene polymer having a long-chain branched structure. For example, polymers that show rise in viscosity in the measurement of elongational viscosity are also long-chain polymers. Included in ethylene polymers having a branched structure. Of the ethylene-based polymers having a long-chain branched structure, those satisfying the formula of the present invention are suitable as those having a specific long-chain branched structure.
Specific examples of the long-chain branched structure that controls the molding speed include a star-shaped branched polymer and a comb-shaped branched polymer, but are not limited thereto.

Ethylene polymer having a long-chain branched structure according to the present invention (II) is, for example, it can be cited one degree of long chain polymer branching is present per 10000 carbon chain, which, for example, ¹³ C- This can be confirmed by NMR measurement. The ethylene-based polymer having a long chain branched structure can be produced by polymerization using a chromium catalyst such as a Philips catalyst or a metallocene catalyst as a single site catalyst as a polymerization catalyst.
In addition, as the ethylene polymer (II) having a long-chain branched structure, polyethylene having a terminal vinyl group (macromonomer) is generated by chain transfer to ethylene, and a long-chain is obtained through copolymerization of the macromonomer and ethylene. A polymer having a branched structure can be obtained.
Among the metallocene catalysts, a catalyst having a metallocene complex having a specific structure is preferable, and a metallocene catalyst having a cyclopentadienyl ring and a heterocyclic aromatic group or a metallocene catalyst having a cyclopentadienyl ring and a fluorenyl ring is particularly preferable.

  The blending amount of the ethylene polymer (II) is 20 to 50% by weight with respect to the other components 50 to 80% by weight, preferably 55 to 64% by weight, based on the whole polyethylene of the present invention. 36 to 45% by weight, more preferably 38 to 45% by weight with respect to 55 to 62% by weight of the other components, and particularly preferably 38 to 40% by weight with respect to 60 to 62% by weight of the other components. If the blending amount of the ethylene-based polymer (II) is less than 20% by weight, the long-term durability of the polyethylene of the present invention, particularly SCG using FNCT as an index may be lowered. On the other hand, if it exceeds 50% by weight, the MFR and density of the polyethylene of the present invention are lowered, and there is a possibility that the polymer is lowered in fluidity, rigidity and pressure resistance.

  The ethylene polymer (II) is preferably polymerized with a metallocene catalyst containing Ti, Zr, or Hf. Examples of the metallocene catalyst include a combination of a complex called a metallocene catalyst in which a ligand having a cyclopentadiene skeleton is coordinated to a transition metal and a promoter. Specific examples of the metallocene catalyst include a complex catalyst in which a ligand having a cyclopentadiene skeleton such as methylcyclopentadiene, dimethylcyclopentadiene, and indene is coordinated to a transition metal containing Ti, Zr, Hf, and the like. Examples of the catalyst include a combination of organic metal compounds of Group 1 to Group 3 elements such as aluminoxane, and a supported type in which these complex catalysts are supported on a carrier such as silica.

The metallocene catalyst preferably used in the present invention contains the following components (A) and (B), and is a catalyst combined with the component (C) as necessary.
Component (A): Metallocene complex Component (B): Compound that reacts with component (A) to form a cationic metallocene compound Component (C): Fine particle carrier

(1) Component (A)
As the component (A), a metallocene compound of a Group 4 transition metal is used. Specifically, compounds represented by the following general formulas (I) to (VI) are used.
^{_{(C 5 H 5-a R}} 1 a) (C 5 H 5-b R 2 b) MXY (I)
^{_{Q (C 5 H 4-c}} R 1 c) (C 5 H 4-d R 2 d) MXY (II)
Q ′ (C ₅ H _4-e R ³ _e ) ZMXY (III)
^{_{(C 5 H 5-f R}} 3 f) ZMXY (IV)
^{_{(C 5 H 5-f R}} 3 f) MXYW (V)
Q ″ (C ₅ H _{5 -g} R ⁴ _g ) (C ₅ H _{5 -h} R ⁵ _h ) MXY (VI)

Here, Q represents a binding group that bridges two conjugated five-membered ring ligands, Q ′ represents a binding group that bridges the conjugated five-membered ring ligand and the Z group, and Q ″ represents , R ⁴ and R ⁵ represent a bonding group, M represents Ti, Zr, or Hf, X, Y, and W each independently represent hydrogen, halogen, or a hydrocarbon having 1 to 20 carbon atoms. A group, an oxygen-containing hydrocarbon group having 1 to 20 carbon atoms, a nitrogen-containing hydrocarbon group having 1 to 20 carbon atoms, a phosphorus-containing hydrocarbon group having 1 to 20 carbon atoms, or a silicon-containing hydrocarbon group having 1 to 20 carbon atoms. Z represents a ligand containing oxygen and sulfur, a silicon-containing hydrocarbon group having 1 to 40 carbon atoms, a nitrogen-containing hydrocarbon group having 1 to 40 carbon atoms, or a phosphorus-containing hydrocarbon group having 1 to 40 carbon atoms. Show.

R ^{1 to} R ⁵ are each independently a hydrocarbon group having 1 to 20 carbon atoms, a halogen group, a halogen-containing hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group, an aryloxy group, an oxygen-containing hydrocarbon group, A sulfur-containing hydrocarbon group, a silicon-containing hydrocarbon group, a phosphorus-containing hydrocarbon group, a nitrogen-containing hydrocarbon group or a boron-containing hydrocarbon group is shown. Two adjacent R ¹ , 2 R ² , 2 R ³ , 2 R ⁴ , or 2 R ⁵ are bonded to each other to form a ring having 4 to 10 carbon atoms. You may do it. A, b, c, d, e, f, and h are 0 ≦ a ≦ 5, 0 ≦ b ≦ 5, 0 ≦ c ≦ 4, 0 ≦ d ≦ 4, 0 ≦ e ≦ 4, and 0 ≦, respectively. It is an integer that satisfies f ≦ 5, 0 ≦ g ≦ 5, and 0 ≦ h ≦ 5.

A bonding group Q that bridges between two conjugated five-membered ring ligands, a bonding group Q ′ that bridges a conjugated five-membered ring ligand and a Z group, and bridges R ⁴ and R ⁵ Specific examples of Q ″ include the following.
That is, an alkylene group such as a methylene group, an ethylene group, an ethylidene group, a propylidene group, an isopropylidene group, a phenylmethylidene group, an alkylidene group such as a diphenylmethylidene group, a dimethylsilylene group, a diethylsilylene group, a dipropylsilylene group , Silicon-containing crosslinking groups such as diphenylsilylene group, methylethylsilylene group, methylphenylsilylene group, methyl-t-butylsilylene group, disilylene group, tetramethyldisylylene group, germanium-containing crosslinking group, alkylphosphine, amine, etc. It is. Among these, an alkylene group, an alkylidene group, a silicon-containing crosslinking group, and a germanium-containing crosslinking group are particularly preferably used.

Specific Zr complexes represented by the above general formulas (I), (II), (III), (IV), (V) and (VI) are exemplified below, but Zr is replaced with Hf or Ti. The same compounds can be used as well.
In addition, the component (A) represented by the general formulas (I), (II), (III), (IV), (V) and (VI) may be a compound represented by the same general formula or a different general formula. It can be used as a mixture of two or more of the compounds shown.

Compounds of general formula (I):
Biscyclopentadienylzirconium dichloride, bis (2-methylindenyl) zirconium dichloride, bis (2-methyl-4,5benzoindenyl) zirconium dichloride, bisfluorenylzirconium dichloride, bis (4H-azurenyl) zirconium dichloride Bis (2-methyl-4H-azurenyl) cyclopentadienylzirconium dichloride, bis (2-methyl-4-phenyl-4H-azurenyl) zirconium dichloride, bis (2-methyl-4- (4-chlorophenyl) -4H -Azulenyl) zirconium dichloride.
Bis (2-furylcyclopentadienyl) zirconium dichloride, bis (2-furylindenyl) zirconium dichloride, bis (2-furyl-4,5-benzoindenyl) zirconium dichloride.

Compound of general formula (II):
Dimethylsilylenebis (1,1′-cyclopentadienyl) zirconium dichloride, dimethylsilylenebis [1,1 ′-(2-methylindenyl)] zirconium dichloride, dimethylsilylenebis [1,1 ′-(2-methyl) Indenyl)] zirconium dichloride, ethylenebis [1,1 ′-(2-methyl-4,5benzoindenyl)] zirconium dichloride, dimethylsilylenebis [1,1 ′-(2-methyl-4-hydroazurenyl)] Zirconium dichloride, dimethylsilylenebis [1,1 ′-(2-methyl-4-phenyl-4-hydroazulenyl)] zirconium dichloride, dimethylsilylenebis {1,1 ′-[2-methyl-4- (4-chlorophenyl) -4-hydroazulenyl]} zirconium dichloride, dimethylsilylene bis [ 1,1 ′-(2-Ethyl-4-phenyl-4-hydroazurenyl)] zirconium dichloride, ethylenebis [1,1 ′-(2-methyl-4-hydroazurenyl)] zirconium dichloride.
Dimethylsilylenebis [1,1 ′-(2-furylcyclopentadienyl)] zirconium dichloride, dimethylsilylenebis {1,1 ′-[2- (2-furyl) -4,5-dimethyl-cyclopentadienyl] ]} Zirconium dichloride, dimethylsilylene bis {1,1 ′-{2- [2- (5-trimethylsilyl) furyl] -4,5-dimethyl-cyclopentadienyl} zirconium dichloride, dimethylsilylene bis {1,1 ′ -[2- (2-furyl) indenyl]} zirconium dichloride, dimethylsilylenebis {1,1 ′-[2- (2-furyl) -4-phenyl-indenyl]} zirconium dichloride, isopropylidene (cyclopentadienyl) ) (9-fluorenyl) zirconium dichloride, isopropylidene (cyclopentadienyl) [9- (2,7-t-butyl) fluorenyl] zirconium dichloride, diphenylmethylene (cyclopentadienyl) (9-fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) [9- (2,7-t -Butyl) fluorenyl] zirconium dichloride, dimethylsilylene (cyclopentadienyl) (9-fluorenyl) zirconium dichloride, diphenylsilylene (cyclopentadienyl) [9- (2,7-t-butyl) fluorenyl] zirconium dichloride.

Compound of general formula (III):
(Tertiary butylamide) (tetramethyl-η ⁵ -cyclopentadienyl) -1,2-ethanediylzirconium dichloride, (methylamide)-(tetramethyl-η ⁵ -cyclopentadienyl) -1,2-ethanediyl -Zirconium dichloride, (ethylamide) (tetramethyl-η ⁵ -cyclopentadienyl) -methylenezirconium dichloride, (tertiary butylamide) dimethyl- (tetramethyl-η ⁵ -cyclopentadienyl) silane zirconium dichloride, tertiary butylamido) dimethyl (tetramethyl-eta ⁵ - cyclopentadienyl) silane zirconium dibenzyl, (benzylamide) dimethyl (tetramethyl-eta ⁵ - cyclopentadienyl) silane zirconium dichloride, (phenylalanine phosphine id) dimethacrylate Le (tetramethyl- eta ⁵ - cyclopentadienyl) silane zirconium dibenzyl.

Compound of general formula (IV):
(Cyclopentadienyl) (phenoxy) zirconium dichloride, (2,3-dimethylcyclopentadienyl) (phenoxy) zirconium dichloride, (pentamethylcyclopentadienyl) (phenoxy) zirconium dichloride, (cyclopentadienyl) ( 2,6-di-t-butylphenoxy) zirconium dichloride, (pentamethylcyclopentadienyl) (2,6-di-i-propylphenoxy) zirconium dichloride.

Compound of general formula (V):
(Cyclopentadienyl) zirconium trichloride, (2,3-dimethylcyclopentadienyl) zirconium trichloride, (pentamethylcyclopentadienyl) zirconium trichloride, (cyclopentadienyl) zirconium triisopropoxide, ( Pentamethylcyclopentadienyl) zirconium triisopropoxide.

Compound of general formula (VI):
Ethylene bis (7,7′-indenyl) zirconium dichloride, dimethylsilylene bis {7,7 ′-(1-methyl-3-phenylindenyl)} zirconium dichloride, dimethylsilylene bis {7,7 ′-[1-methyl -4- (1-naphthyl) indenyl]} zirconium dichloride, dimethylsilylenebis [7,7 '-(1-ethyl-3-phenylindenyl)] zirconium dichloride, dimethylsilylenebis {7,7'-[1- Isopropyl-3- (4-chlorophenyl) indenyl]} zirconium dichloride.

In addition, the compound which replaced the silylene group of the compound of these specific examples with the germylene group is illustrated as a suitable compound.
Among the transition metal compound components (A) described above, preferred metallocene complexes for producing the ethylene-based polymer (II) include metallocene complexes represented by general formula (I) or general formula (II) In addition, a metallocene complex represented by the general formula (II) is preferable from the viewpoint of being able to produce a high molecular weight polymer and having excellent copolymerizability in the copolymerization of ethylene and another α-olefin. . The ability to produce a high molecular weight product has the advantage that polymers with various molecular weights can be designed by adjusting the molecular weight of various polymers as described below.
One method for satisfying the properties of the polyethylene of the present invention is to introduce long chain branching into the ethylene polymer. From the standpoint that polyethylene having high molecular weight and long chain branching can be produced, Among the metallocene complexes represented by the formula (II), the following two compound groups are preferable.

As a preferred embodiment, the first compound group is a bridged metallocene complex containing at least one heterocyclic aromatic group in the compound as R ^{1 to} R ² . Preferred heterocyclic aromatic groups include the group consisting of a furyl group, a benzofuryl group, a thienyl group, and a benzothienyl group. These substituents may further have a substituent such as a silicon-containing group. Of the substituents selected from the group consisting of a furyl group, a benzofuryl group, a thienyl group, and a benzothienyl group, a furyl group and a benzofuryl group are more preferable. Further, these substituents are preferably introduced at the 2-position of the substituted cyclopentadienyl group or the substituted indenyl group, and at least one other substituted cyclopentadienyl group having no condensed ring structure is introduced. It is particularly preferred that the compound has.

  The second group of compounds is a bridged metallocene complex in which a substituted cyclopentadienyl group and a substituted fluorenyl group are combined.

  These metallocene complexes are preferably used as supported catalysts as described later. In the first group of compounds, the furyl group interacts with the so-called heteroatom contained in the thienyl group and the solid acid on the support, causing non-uniformity in the active site structure and easily generating long chain branching. I think. Also in the second compound group, it is thought that the use of a supported catalyst changed the space around the active site, so that long chain branching was easily generated.

(2) Component (B)
In the method for producing an ethylene polymer (II) according to the present invention, as an essential component of an olefin polymerization catalyst, in addition to the above component (A), a metallocene compound (hereinafter referred to as “component (A)” or “component (A)” A compound that forms a cationic metallocene compound by reacting with the compound (component (B), hereinafter may be simply referred to as “B”); Component (C), hereinafter simply referred to as “C”) is characteristic.

As one of the compounds (B) that react with the metallocene compound (A) to form a cationic metallocene compound, an organoaluminum oxy compound can be mentioned.
The organoaluminum oxy compound has Al—O—Al bonds in the molecule, and the number of bonds is usually in the range of 1 to 100, preferably 1 to 50. Such an organoaluminum oxy compound is usually a product obtained by reacting an organoaluminum compound with water.
The reaction between organoaluminum and water is usually carried out in an inert hydrocarbon (solvent). As the inert hydrocarbon, aliphatic hydrocarbons such as pentane, hexane, heptane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, alicyclic hydrocarbons and aromatic hydrocarbons can be used. Preference is given to using aromatic hydrocarbons.

As the organoaluminum compound used for the preparation of the organoaluminum oxy compound, any compound represented by the following general formula (4) can be used, but trialkylaluminum is preferably used.
R ⁵ _t AlX ³ _3-t (4)
(In the formula, R ⁵ represents a hydrocarbon group such as an alkyl group, alkenyl group, aryl group or aralkyl group having 1 to 18 carbon atoms, preferably 1 to 12 carbon atoms, and X ³ represents a hydrogen atom or a halogen atom. , T represents an integer of 1 ≦ t ≦ 3.)

The alkyl group of the trialkylaluminum may be any of methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, pentyl group, hexyl group, octyl group, decyl group, dodecyl group, etc. It is particularly preferred that
Two or more of the above organoaluminum compounds can be mixed and used.

The reaction ratio (water / Al molar ratio) between water and the organoaluminum compound is preferably 0.25 / 1 to 1.2 / 1, particularly preferably 0.5 / 1 to 1/1, and the reaction temperature is Usually, it is -70-100 degreeC, Preferably it exists in the range of -20-20 degreeC. The reaction time is usually selected in the range of 5 minutes to 24 hours, preferably 10 minutes to 5 hours. As water required for the reaction, not only mere water but also crystal water contained in copper sulfate hydrate, aluminum sulfate hydrate and the like and components capable of generating water in the reaction system can be used.
Of the organoaluminum oxy compounds described above, those obtained by reacting alkylaluminum with water are usually called aluminoxanes, particularly methylaluminoxane (including those substantially consisting of methylaluminoxane (MAO)). Is suitable as an organoaluminum oxy compound.
Of course, as the organoaluminum oxy compound, two or more of the above organoaluminum oxy compounds may be used in combination, and a solution obtained by dispersing or dispersing the organoaluminum oxy compound in the above-described inert hydrocarbon solvent. You may use.

Moreover, a borane compound and a borate compound are mentioned as another specific example of the compound (B) which reacts with a metallocene compound (A) and forms a cationic metallocene compound.
More specifically, the borane compound is represented by triphenylborane, tri (o-tolyl) borane, tri (p-tolyl) borane, tri (m-tolyl) borane, tri (o-fluorophenyl) borane, tris ( p-fluorophenyl) borane, tris (m-fluorophenyl) borane, tris (2,5-difluorophenyl) borane, tris (3,5-difluorophenyl) borane, tris (4-trifluoromethylphenyl) borane, tris (3,5-ditrifluoromethylphenyl) borane, tris (2,6-ditrifluoromethylphenyl) borane, tris (pentafluorophenyl) borane, tris (perfluoronaphthyl) borane, tris (perfluorobiphenyl), tris ( Perfluoroanthryl) borane, tris (perfluorobi) Fuchiru) such as borane and the like.

  Among these, tris (3,5-ditrifluoromethylphenyl) borane, tris (2,6-ditrifluoromethylphenyl) borane, tris (pentafluorophenyl) borane, tris (perfluoronaphthyl) borane, tris (perfluoro) Biphenyl) borane, tris (perfluoroanthryl) borane, and tris (perfluorobinaphthyl) borane are more preferred, and tris (2,6-ditrifluoromethylphenyl) borane, tris (pentafluorophenyl) borane, tris ( Perfluoronaphthyl) borane and tris (perfluorobiphenyl) borane are exemplified as preferred compounds.

When the borate compound is specifically represented, the first example is a compound represented by the following general formula (5).
^{[L 1 -H] + [BR} 6 R 7 X 4 X 5] - (5)

In Formula (5), L ¹ is a neutral Lewis base, H is a hydrogen atom, and [L ¹ -H] is a Bronsted acid such as ammonium, anilinium, phosphonium, or the like.
Examples of ammonium include trialkylammonium such as trimethylammonium, triethylammonium, tripropylammonium, tributylammonium, and tri (n-butyl) ammonium, and dialkylammonium such as di (n-propyl) ammonium and dicyclohexylammonium.

Examples of anilinium include N, N-dialkylanilinium such as N, N-dimethylanilinium, N, N-diethylanilinium, N, N-2,4,6-pentamethylanilinium.
Furthermore, examples of the phosphonium include triarylphosphonium, tributylphosphonium, triarylphosphonium such as tri (methylphenyl) phosphonium, tri (dimethylphenyl) phosphonium, and trialkylphosphonium.

In formula (5), R ⁶ and R ⁷ are the same or different aromatic or substituted aromatic hydrocarbon groups containing 6 to 20, preferably 6 to 16 carbon atoms, and are connected to each other by a bridging group. As the substituent of the substituted aromatic hydrocarbon group, an alkyl group typified by a methyl group, an ethyl group, a propyl group, an isopropyl group or the like, or a halogen such as fluorine, chlorine, bromine or iodine is preferable.
Further, X ⁴ and X ⁵ are a hydride group, a halide group, a hydrocarbon group containing 1 to 20 carbon atoms, a substituted carbon atom containing 1 to 20 carbon atoms in which one or more hydrogen atoms are replaced by halogen atoms. It is a hydrogen group.

  Specific examples of the compound represented by the general formula (5) include tributylammonium tetra (pentafluorophenyl) borate, tributylammonium tetra (2,6-ditrifluoromethylphenyl) borate, tributylammonium tetra (3,5- Ditrifluoromethylphenyl) borate, tributylammonium tetra (2,6-difluorophenyl) borate, tributylammonium tetra (perfluoronaphthyl) borate, dimethylanilinium tetra (pentafluorophenyl) borate, dimethylanilinium tetra (2,6- Ditrifluoromethylphenyl) borate, dimethylanilinium tetra (3,5-ditrifluoromethylphenyl) borate, dimethylanilinium tetra (2,6-difluoropheny) ) Borate, dimethylanilinium tetra (perfluoronaphthyl) borate, triphenylphosphonium tetra (pentafluorophenyl) borate, triphenylphosphonium tetra (2,6-ditrifluoromethylphenyl) borate, triphenylphosphonium tetra (3,5- Ditrifluoromethylphenyl) borate, triphenylphosphonium tetra (2,6-difluorophenyl) borate, triphenylphosphonium tetra (perfluoronaphthyl) borate, trimethylammonium tetra (2,6-ditrifluoromethylphenyl) borate, triethylammonium tetra (Pentafluorophenyl) borate, triethylammonium tetra (2,6-ditrifluoromethylphenyl) borate, triethyla Monium tetra (perfluoronaphthyl) borate, tripropylammonium tetra (pentafluorophenyl) borate, tripropylammonium tetra (2,6-ditrifluoromethylphenyl) borate, tripropylammonium tetra (perfluoronaphthyl) borate, di (1 -Propyl) ammonium tetra (pentafluorophenyl) borate, dicyclohexylammonium tetraphenylborate and the like.

  Among these, tributylammonium tetra (pentafluorophenyl) borate, tributylammonium tetra (2,6-ditrifluoromethylphenyl) borate, tributylammonium tetra (3,5-ditrifluoromethylphenyl) borate, tributylammonium tetra (perfluoro) Naphthyl) borate, dimethylaniliniumtetra (pentafluorophenyl) borate, dimethylaniliniumtetra (2,6-ditrifluoromethylphenyl) borate, dimethylaniliniumtetra (3,5-ditrifluoromethylphenyl) borate, dimethylanilinium Tetra (perfluoronaphthyl) borate is preferred.

Moreover, the 2nd example of a borate compound is represented by following General formula (6).
[L ² ] ⁺ [BR ⁶ R ⁷ X ⁴ X ⁵ ] ⁻ (6)

In the formula (6), L ² is carbocation, methyl cation, ethyl cation, propyl cation, isopropyl cation, butyl cation, isobutyl cation, tert-butyl cation, pentyl cation, tropinium cation, benzyl cation, trityl cation, sodium. A cation, a proton, etc. are mentioned. R ⁶ , R ⁷ , X ⁴ and X ⁵ are the same as defined in the general formula (5).

Specific examples of the compound include trityl tetraphenyl borate, trityl tetra (o-tolyl) borate, trityl tetra (p-tolyl) borate, trityl tetra (m-tolyl) borate, trityl tetra (o-fluorophenyl) borate, Trityltetra (p-fluorophenyl) borate, trityltetra (m-fluorophenyl) borate, trityltetra (3,5-difluorophenyl) borate, trityltetra (pentafluorophenyl) borate, trityltetra (2,6-ditrifluoro) Methylphenyl) borate, trityltetra (3,5-ditrifluoromethylphenyl) borate, trityltetra (perfluoronaphthyl) borate, tropiniumtetraphenylborate, tropiniumtetra (o-tolyl) Rate, tropinium tetra (p-tolyl) borate, tropinium tetra (m-tolyl) borate, tropinium tetra (o-fluorophenyl) borate, tropinium tetra (p-fluorophenyl) borate, tropinium tetra (m- Fluorophenyl) borate, tropinium tetra (3,5-difluorophenyl) borate, tropinium tetra (pentafluorophenyl) borate, tropinium tetra (2,6-ditrifluoromethylphenyl) borate, tropinium tetra (3,5 - ditrifluoromethylphenyl) borate, tropicity tetra (perfluoro-naphthyl) _{borate, NaBPh 4, NaB (o-} CH 3 -Ph) 4, NaB (p-CH 3 -Ph) 4, NaB (m-CH 3 - Ph) ₄ , Na _{B (o-F-Ph)} 4, NaB (p-F-Ph) 4, NaB (m-F-Ph) 4, NaB (3,5-F 2 -Ph) 4, NaB (C 6 F 5) ₄ , NaB (2,6- (CF ₃ ) ₂ -Ph) ₄ , NaB (3,5- (CF ₃ ) ₂ -Ph) ₄ , NaB (C ₁₀ F ₇ ) ₄ , H ⁺ BPh ₄ · 2 diethyl _{^{ethers, H + B (3,5-F}} 2 -Ph) 4 · 2 diethyl ^{_{ether, H + B (C 6 F}} 5) 4 - · 2 diethyl _{^{ether, H + B (2,6- (CF}} 3) 2 _{-Ph) 4} · 2 diethyl _{^{ether, H + B (3,5- (CF}} 3) 2 -Ph) 4 · 2 diethyl ^ether, can be exemplified _{H + B (C 10 H 7} ) 4 · 2 diethyl ether it can.

Among these, trityltetra (pentafluorophenyl) borate, trityltetra (2,6-ditrifluoromethylphenyl) borate, trityltetra (3,5-ditrifluoromethylphenyl) borate, trityltetra (perfluoronaphthyl) borate, Tropinium tetra (pentafluorophenyl) borate, tropinium tetra (2,6-ditrifluoromethylphenyl) borate, tropinium tetra (3,5-ditrifluoromethylphenyl) borate, tropinium tetra (perfluoronaphthyl) borate, _{NaB (C 6 F 5) 4} , NaB (2,6- (CF 3) 2 -Ph) 4, NaB (3,5- (CF 3) 2 -Ph) 4, NaB (C 10 F 7) 4, ^{_{H + B (C 6 F 5}} ) 4 - · 2 diethyl _{^{Ether, H + B (2,6- (CF}} 3) 2 -Ph) 4 · 2 diethyl _{^{ether, H + B (3,5- (CF}} 3) 2 -Ph) 4 · 2 diethyl ^{ether, H} + B ( C ₁₀ H _{7) 4} · 2 diethyl ether.

More preferably, among these, trityltetra (pentafluorophenyl) borate, trityltetra (2,6-ditrifluoromethylphenyl) borate, tropiniumtetra (pentafluorophenyl) borate, tropiniumtetra (2,6-ditrifluoro) methylphenyl) _{borate, NaB (C 6 F 5)} 4, NaB (2,6- (CF 3) 2 -Ph) 4, H + B (C 6 F 5) 4 - · 2 diethyl ^{ether, H} + B ( _{2,6- (CF 3) 2 -Ph)} 4 · 2 diethyl _{^{ether, H + B (3,5- (CF}} 3) 2 -Ph) 4 · 2 diethyl ^{_{ether, H + B (C 10 H}} 7) 4 -2 diethyl ether is mentioned.

(3) Component (C)
Examples of the fine particle carrier as the component (C) include an inorganic carrier, a particulate polymer carrier, and a mixture thereof. As the inorganic carrier, a metal, a metal oxide, a metal chloride, a metal carbonate, a carbonaceous material, or a mixture thereof can be used.
Suitable metals that can be used for the inorganic carrier include, for example, iron, aluminum, nickel, and the like.

Further, as the metal oxide, either alone oxide or composite oxide of the Periodic Table 1-14 Group elements include, for _{example, SiO 2, Al 2 O 3} , MgO, CaO, B 2 O 3, TiO 2, _{ZrO 2, Fe 2 O 3,} Al 2 O 3 · MgO, Al 2 O 3 · CaO, Al 2 O 3 · SiO 2, Al 2 O 3 · MgO · CaO, Al 2 O 3 · MgO · SiO 2, Al Examples include various natural or synthetic single oxides or composite oxides such as ₂ O ₃ .CuO, Al ₂ O ₃ .Fe ₂ O ₃ , Al ₂ O ₃ .NiO, and SiO ₂ .MgO.
Here, the above formula is not a molecular formula but represents only the composition, and the structure and component ratio of the composite oxide used in the present invention are not particularly limited.
In addition, the metal oxide used in the present invention may absorb a small amount of moisture or may contain a small amount of impurities.

As the metal chloride, for example, an alkali metal or alkaline earth metal chloride is preferable, and specifically, MgCl ₂ , CaCl _{2 and the} like are particularly preferable.
As the metal carbonate, carbonates of alkali metals and alkaline earth metals are preferable, and specific examples include magnesium carbonate, calcium carbonate, barium carbonate and the like.
Examples of the carbonaceous material include carbon black and activated carbon.
Any of the above inorganic carriers can be suitably used in the present invention, but the use of metal oxides, silica, alumina and the like is particularly preferable.

These inorganic carriers are usually calcined in air or an inert gas such as nitrogen or argon at 200 to 800 ° C., preferably 400 to 600 ° C., and the amount of surface hydroxyl groups is 0.8 to 1.5 mmol / g. It is preferable to adjust to use.
The properties of these inorganic carriers are not particularly limited, but usually the average particle size is 5 to 200 μm, preferably 10 to 150 μm, the average pore size is 20 to 1000 mm, preferably 50 to 500 mm, and the specific surface area is 150 to 1000 m. ² / g, preferably 200-700 m ² / g, pore volume 0.3-2.5 cm ³ / g, preferably 0.5-2.0 cm ³ / g, apparent specific gravity 0.10-0 It is preferred to use an inorganic carrier having a density of .50 g / cm ³ .

  Of course, the above-mentioned inorganic carriers can be used as they are, but as a pretreatment, these carriers are trimethylaluminum, triethylaluminum, triisobutylaluminum, trihexylaluminum, tripropylaluminum, tributylaluminum, trioctylaluminum, tridecylaluminum, It can be used after contacting an organoaluminum compound such as diisobutylaluminum hydride or an organoaluminum oxy compound containing an Al—O—Al bond.

  The metallocene catalyst according to the present invention is a catalyst comprising a metallocene compound (A), a compound (B) that reacts with the metallocene compound (A) to form a cationic metallocene compound, and if necessary, a fine particle carrier (C). There are no particular limitations on the method of contacting each component in obtaining the above, and for example, the following methods can be arbitrarily employed.

(I) After contacting the metallocene compound (A) with the compound (B) that reacts with the metallocene compound (A) to form a cationic metallocene compound, the fine particle carrier (C) is contacted.
(II) After contacting the metallocene compound (A) with the fine particle carrier (C), the compound (B) that reacts with the metallocene compound (A) to form a cationic metallocene compound is contacted.
(III) After contacting the metallocene compound (A) with the compound (B) that generates a cationic metallocene compound and the fine particle carrier (C), the metallocene compound (A) is contacted.

Of these contact methods, (I) and (III) are preferred, and (I) is most preferred. In any contact method, usually in an inert atmosphere such as nitrogen or argon, generally aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene (usually having 6 to 12 carbon atoms), heptane, hexane, decane and dodecane. In the presence of a liquid inert hydrocarbon such as an aliphatic or alicyclic hydrocarbon (usually having 5 to 12 carbon atoms) such as cyclohexane, a method of bringing each component into contact with stirring or non-stirring is employed.
This contact is usually −100 ° C. to 200 ° C., preferably −50 ° C. to 100 ° C., more preferably 0 ° C. to 50 ° C., for 5 minutes to 50 hours, preferably 30 minutes to 24 hours, more preferably. It is desirable to carry out in 30 minutes to 12 hours.

  In addition, as described above, certain components are soluble when contacting the metallocene compound (A), the compound (B) that reacts with the metallocene compound (A) to form a cationic metallocene compound and the fine particle carrier (C). Either an aromatic hydrocarbon solvent that is hardly soluble or an aliphatic or alicyclic hydrocarbon solvent in which a certain component is insoluble or hardly soluble can be used.

  In the case where the contact reaction between the components is performed stepwise, this may be used as it is as the solvent for the subsequent contact reaction without removing the solvent used in the previous step. In addition, after the previous catalytic reaction using a soluble solvent, liquid inert hydrocarbons in which certain components are insoluble or sparingly soluble (for example, aliphatics such as pentane, hexane, decane, dodecane, cyclohexane, benzene, toluene, xylene, etc.) Hydrocarbons, alicyclic hydrocarbons or aromatic hydrocarbons) and the desired product is recovered as a solid or once or part of the soluble solvent is removed by means such as drying. After removing the product as a solid, the subsequent catalytic reaction of the desired product can also be carried out using any of the inert hydrocarbon solvents described above. In this invention, it does not prevent performing contact reaction of each component in multiple times.

  In the present invention, the use ratio of the metallocene compound (A), the compound (B) that reacts with the metallocene compound (A) to form a cationic metallocene compound, and the fine particle carrier (C) is not particularly limited. A range is preferred.

When an organoaluminum oxy compound is used as the compound (B) that reacts with the metallocene compound (A) to form a cationic metallocene compound, the aluminum of the organoaluminum oxy compound relative to the transition metal (M) in the metallocene compound (A) is used. The atomic ratio (Al / M) is usually in the range of 1 to 100,000, preferably 5 to 1000, more preferably 50 to 200, and when a borane compound or a borate compound is used, transition in the metallocene compound The atomic ratio (B / M) of boron to metal (M) is usually selected within the range of 0.01 to 100, preferably 0.1 to 50, and more preferably 0.2 to 10.
Further, when a mixture of an organoaluminum oxy compound, a borane compound, and a borate compound is used as the compound (B) for generating a cationic metallocene compound, for each compound in the mixture, the transition metal (M) It is desirable to select at the same usage ratio as above.

  The fine particle carrier (C) is used in an amount of 0.0001-5 mmol, preferably 0.001-0.5 mmol, more preferably 0.01-0.1 mmol, of the transition metal in the metallocene compound (A). It is 1g per hit.

  The metallocene compound (A), the compound (B) that reacts with the metallocene compound (A) to form a cationic metallocene compound, and the fine particle carrier (C) are any of the contact methods (I) to (III). Then, the catalyst for olefin polymerization can be obtained as a solid catalyst by removing the solvent. The removal of the solvent is desirably performed under normal pressure or reduced pressure at 0 to 200 ° C., preferably 20 to 150 ° C. for 1 minute to 50 hours, preferably 10 minutes to 10 hours.

The metallocene catalyst can also be obtained by the following method.
(IV) The metallocene compound (A) and the fine particle carrier (C) are contacted to remove the solvent, which is used as a solid catalyst component, and an organoaluminum oxy compound, borane compound, borate compound or a mixture thereof under polymerization conditions Make contact.
(V) The organoaluminum oxy compound, borane compound, borate compound or a mixture thereof and the fine particle carrier (C) are contacted to remove the solvent, using this as a solid catalyst component, and the metallocene compound (A) under polymerization conditions Make contact.
In the case of the contact methods (IV) and (V), the same conditions as described above can be used for the component ratio, contact conditions, and solvent removal conditions.

The compound (B) that reacts with the metallocene compound (A), which is an essential component of the method for producing the ethylene-based polymer (II) according to the present invention, to form a cationic metallocene compound also serves as the fine particle carrier (C). A layered silicate can also be used as a component.
The layered silicate is a silicate compound having a crystal structure in which planes formed by ionic bonds or the like are stacked in parallel with each other with a weak binding force.
Most layered silicates are naturally produced mainly as the main component of clay minerals, but these layered silicates are not limited to natural ones and may be artificially synthesized.

  Among these, montmorillonite, sauconite, beidellite, nontronite, saponite, hectorite, stevensite, bentonite, teniolite and the like, smectite group, vermiculite group and mica group are preferable.

In general, natural products are often non-ion-exchangeable (non-swellable). In that case, in order to have preferable ion-exchange (or swellable), ion exchange (or swellable) is provided. It is preferable to perform the process for providing. Among such treatments, particularly preferred are the following chemical treatments.
Here, as the chemical treatment, any of a surface treatment for removing impurities adhering to the surface and a treatment that affects the crystal structure and chemical composition of the layered silicate can be used.
Specifically, (a) acid treatment performed using hydrochloric acid, sulfuric acid, etc., (b) alkali treatment performed using NaOH, KOH, NH _3, etc., (c) selected from Groups 2 to 14 of the periodic table Salt treatment with a salt comprising at least one anion selected from the group consisting of a cation containing at least one atom and a halogen atom or an anion derived from an inorganic acid, (d) alcohol, hydrocarbon Examples thereof include organic compounds such as compounds, formamide and aniline. These processes may be performed independently or two or more processes may be combined.

  The layered silicate can control the particle properties by pulverization, granulation, sizing, fractionation, etc. at any time before, during, or after all the steps. The method can be any purposeful. In particular, for granulation methods, for example, spray granulation method, rolling granulation method, compression granulation method, stirring granulation method, briquetting method, compacting method, extrusion granulation method, fluidized bed granulation Method, emulsion granulation method and submerged granulation method. Particularly preferable granulation methods are the spray granulation method, the rolling granulation method and the compression granulation method.

  Of course, the layered silicate can be used as it is, but these layered silicates are trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum, It can be used in combination with an organoaluminum compound such as diisobutylaluminum hydride or an organoaluminum oxy compound containing an Al—O—Al bond.

In the metallocene catalyst according to the present invention, in order to support the metallocene compound (A) on the layered silicate, the metallocene compound (A) and the layered silicate are brought into contact with each other, or the metallocene compound (A) or organoaluminum compound. The layered silicates may be brought into contact with each other.
The contact method of each component is not specifically limited, For example, the following methods are arbitrarily employable.
(VI) The metallocene compound (A) and the organoaluminum compound are contacted and then contacted with the layered silicate support.
(VII) The metallocene compound (A) and the layered silicate support are contacted and then contacted with the organoaluminum compound.
(VIII) The organoaluminum compound and the layered silicate support are contacted and then contacted with the metallocene compound (A).

  Of these contact methods, (VI) and (VIII) are preferred. In any contact method, usually in an inert atmosphere such as nitrogen or argon, generally aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene (usually 6 to 12 carbon atoms), heptane, hexane, decane and dodecane. In the presence of a liquid inert hydrocarbon such as an aliphatic or alicyclic hydrocarbon (usually having 5 to 12 carbon atoms) such as cyclohexane, a method of bringing each component into contact with stirring or non-stirring is employed.

The use ratio of the metallocene compound (A), the organoaluminum compound, and the layered silicate carrier is not particularly limited, but the following ranges are preferable.
The supported amount of the metallocene compound (A) is 0.0001 to 5 mmol, preferably 0.001 to 0.5 mmol, more preferably 0.01 to 0.1 mmol, per 1 g of the layered silicate support.
In the case of using an organoaluminum compound, the amount of Al supported is preferably in the range of 0.01 to 100 mol, preferably 0.1 to 50 mol, more preferably 0.2 to 10 mol.

For the method of supporting and removing the solvent, the same conditions as those for the inorganic carrier can be used.
When a layered silicate is used as a component that serves both as the catalyst component (B) and the component (C), the polymerization activity is high and the productivity of an ethylene-based polymer having a long chain branch is improved.
The olefin polymerization catalyst thus obtained may be used after the prepolymerization of the monomer if necessary.

  As an example of producing a metallocene catalyst, for example, it can be produced by referring to “catalyst” and “mixing ratio and conditions of raw materials” described in JP-T-2002-535339 and JP-A-2004-189869. it can. The index of the polymer can be controlled by various polymerization conditions, and can be controlled by, for example, the methods described in JP-A-2-269705 and JP-A-3-21607.

  The ethylene polymer (II) is a homopolymer of ethylene, or ethylene and an α-olefin having 3 to 12 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene. , 1-octene and the like. Also, copolymerization with a diene for the purpose of modification is possible. Examples of the diene compound used at this time include butadiene, 1,4-hexadiene, ethylidene norbornene, dicyclopentadiene, and the like. The comonomer content during the polymerization can be arbitrarily selected. For example, in the case of copolymerization of ethylene and an α-olefin having 3 to 12 carbon atoms, an ethylene / α-olefin copolymer is used. The α-olefin content therein is 0 to 40 mol%, preferably 0 to 30 mol%.

The molecular weight of the produced polymer can be adjusted to some extent by changing the polymerization conditions such as the polymerization temperature and the molar ratio of the catalyst, but the molecular weight can be adjusted more effectively by adding hydrogen to the polymerization reaction system. Can do.
Moreover, even if a component for the purpose of removing moisture, a so-called scavenger, is added to the polymerization system, the polymerization can be carried out without any trouble.
Such scavengers include organoaluminum compounds such as trimethylaluminum, triethylaluminum and triisobutylaluminum, the organoaluminum oxy compounds, modified organoaluminum compounds containing branched alkyl, organozinc compounds such as diethyl zinc and dibutyl zinc, diethyl Organic magnesium compounds such as magnesium, dibutylmagnesium and ethylbutylmagnesium, and grinier compounds such as ethylmagnesium chloride and butylmagnesium chloride are used. Of these, triethylaluminum, triisobutylaluminum, and ethylbutylmagnesium are preferable, and triethylaluminum is particularly preferable.
The present invention can also be applied to a multistage polymerization system having two or more stages having different polymerization conditions such as hydrogen concentration, monomer amount, polymerization pressure, and polymerization temperature without any trouble.

  The ethylene polymer (II) can be produced by a production process such as a gas phase polymerization method, a solution polymerization method, or a slurry polymerization method, and preferably a slurry polymerization method. Among the polymerization conditions for the ethylene polymer (II), the polymerization temperature can be selected from the range of 0 to 200 ° C. In slurry polymerization, polymerization is performed at a temperature lower than the melting point of the produced polymer. The polymerization pressure can be selected from the range of atmospheric pressure to about 10 MPa. It is selected from aliphatic hydrocarbons such as hexane and heptane, aromatic hydrocarbons such as benzene, toluene and xylene, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, etc. in a state where oxygen and water are substantially cut off. It can be produced by slurry polymerization of ethylene and α-olefin in the presence of an inert hydrocarbon solvent.

  As long as the ethylene polymer (II) satisfies a predetermined range, polymerization is successively performed in a single polymerizer, a plurality of reactors connected in series or in parallel, and a plurality of ethylene polymers are polymerized separately. It may be mixed later.

3. Other Components The polyethylene for pipes and joints of the present invention preferably contains 20 to 50% by weight of a specific ethylene polymer (II), but the other components satisfy the characteristics of the present invention. Any polyethylene can be used without limitation.
In the present invention, the polyethylene of the present invention is easy to adjust and, as will be described below, it becomes a particularly preferable polyethylene for pipes and joints. Therefore, as another component, a specific ethylene polymer (I) is used as the present invention. It is preferable to use 50 to 80% by weight based on the whole polyethylene.
Preferably, the ethylene polymer (I) has a melt flow rate (MFR (I)) of 50 to 200 g / 10 min at a temperature of 190 ° C. and a load of 2.16 Kg, and a density of 0.955 to 0.975 g / Preferably it is cm ³ . More preferably, the ethylene polymer (I) has an MFR of 80 to 150 g / 10 min and a density of 0.966 to 0.973 g / cm ³ .

The MFR of the ethylene polymer (I) is preferably 50 to 200 g / 10 minutes, more preferably 80 to 150 g / 10 minutes. When the MFR is less than 50 g / 10 min, the molecular weight increases, the fluidity decreases, and the moldability cannot be ensured. On the other hand, when the MFR exceeds 200 g / 10 min, the impact resistance may be lowered or the SCG may be lowered.
Moreover, it is preferable that the density of ethylene-type polymer (I) is 0.955-0.975 g / cm < ³ >, More preferably, it is 0.966-0.973 g / cm < ³ >. If the density is less than 0.955 g / cm ³ , the pressure resistance of the final polyethylene may be reduced. On the other hand, when the density exceeds 0.975 g / cm ³ , it becomes difficult to produce polyethylene, and even if it can be produced, the final polyethylene may have a markedly reduced impact resistance.

Here, MFR and density are values measured by the measurement methods described above.
Moreover, MFR is mainly adjusted with the amount of hydrogen at the time of manufacture, and a density can be adjusted with the quantity of the alpha olefin at the time of manufacture mainly.

The polymerization catalyst for the ethylene polymer (I) is not particularly limited, but a Ziegler catalyst is preferably used from the balance of MFR and density. An example of a preferable catalyst is a solid Ziegler catalyst comprising a Ti and / or V compound and an organometallic compound of Group 1 to Group 3 elements of the periodic table.
Solid Ziegler catalysts include solid catalysts containing titanium (Ti) and / or vanadium (V) and magnesium (Mg), and organometallic compounds that can be used with these components include organoaluminum compounds, Alkyl aluminum is preferred. The amount of the organoaluminum compound used in the polymerization reaction is not particularly limited, but when used, it is preferably in the range of 0.05 to 1000 mol with respect to 1 mol of the transition metal compound.

  As an example of a Ziegler catalyst, for example, “catalyst” described in Example 1 of JP-A-63-202602 is used, and as a polymerization method, described in Example 1 of JP-A-2004-123955, etc. The ethylene polymer (I) can be produced by taking into consideration the “mixing ratio and conditions of raw materials”.

In the present invention, the ethylene polymer (I) is preferably a homopolymer of ethylene and / or a copolymer of ethylene and an α-olefin, that is, an ethylene polymer. preferable.
The ethylene polymer (I) is a homopolymer of ethylene, or ethylene and an α-olefin having 3 to 12 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene. , 1-octene and the like. Also, copolymerization with a diene for the purpose of modification is possible. Examples of the diene compound used at this time include butadiene, 1,4-hexadiene, ethylidene norbornene, dicyclopentadiene, and the like.
The comonomer content during the polymerization can be arbitrarily selected. For example, in the case of copolymerization of ethylene and an α-olefin having 3 to 12 carbon atoms, an ethylene / α-olefin copolymer is used. The α-olefin content therein is 0 to 40 mol%, preferably 0 to 30 mol%.

  The ethylene polymer (I) can be produced by a production process such as a gas phase polymerization method, a solution polymerization method, or a slurry polymerization method, and preferably a slurry polymerization method. Among the polymerization conditions for the ethylene polymer, the polymerization temperature can be selected from the range of 0 to 300 ° C. In slurry polymerization, polymerization is performed at a temperature lower than the melting point of the produced polymer. The polymerization pressure can be selected from the range of atmospheric pressure to about 10 MPa. It is selected from aliphatic hydrocarbons such as hexane and heptane, aromatic hydrocarbons such as benzene, toluene and xylene, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, etc. in a state where oxygen and water are substantially cut off. It can be produced by slurry polymerization of ethylene and α-olefin in the presence of an inert hydrocarbon solvent.

The hydrogen supplied to the polymerization vessel in the slurry polymerization is consumed as a chain transfer agent, determines the average molecular weight of the produced ethylene-based polymer, and partly dissolves in a solvent and is discharged from the polymerization vessel. The solubility of hydrogen in the solvent is small, and the hydrogen concentration near the polymerization active point of the catalyst is low unless a large amount of gas phase is present in the polymerization vessel. Therefore, if the hydrogen supply amount is changed, the hydrogen concentration at the polymerization active point of the catalyst changes rapidly, and the molecular weight of the produced ethylene polymer changes following the hydrogen supply amount in a short time. Therefore, a more homogeneous product can be produced by changing the hydrogen supply rate in a short cycle. For these reasons, it is preferable to employ a slurry polymerization method as the polymerization method. In addition, the aspect of changing the hydrogen supply amount is preferably changed discontinuously rather than continuously because the effect of broadening the molecular weight distribution can be obtained.
In the ethylene polymer (I) according to the present invention, as described above, it is important to change the hydrogen supply amount, but other polymerization conditions, for example, the polymerization temperature, the catalyst supply amount, and the supply of olefins such as ethylene. It is also important to change the amount, the supply amount of a comonomer such as 1-hexene, the supply amount of a solvent, etc., at the same time as the hydrogen change or separately.

  The ethylene polymer (I) can be composed of a plurality of components. The ethylene-based polymer (I) may be a polymer that is successively polymerized in a multistage polymerization reactor using one type of catalyst, and may be converted into a single-stage or multistage polymerization reactor using a plurality of types of catalysts. The polymer manufactured by the above may be used, and the polymer polymerized using one or more kinds of catalysts may be mixed.

When using a so-called multistage polymerization method in which a plurality of reactors connected in series are successively polymerized, a high molecular weight component is produced in the first polymerization zone (first-stage reactor) as long as a predetermined range is satisfied. Even in the order of transferring the obtained polymer to the next reaction zone (second stage reactor) and producing low molecular weight components in the second stage reactor, Conversely, in the first polymerization zone (first-stage reactor), polymerization was performed using production conditions for producing low molecular weight components, and the resulting polymer was polymerized in the next reaction zone (second-stage reactor). ) And the order in which the high molecular weight components are produced in the second stage reactor may be used.
A specific preferable polymerization method is the following method. That is, using a Ziegler catalyst containing a titanium-based transition metal compound and an organoaluminum compound and two reactors, introducing ethylene and α-olefin into the first stage reactor, A polymer is produced, and the polymer extracted from the first-stage reactor is transferred to the second-stage reactor, and ethylene and hydrogen are introduced into the second-stage reactor. This is a method for producing a polymer having a molecular weight component.
In the case of multistage polymerization, the amount of ethylene-based polymer produced in the second and subsequent polymerization zones and its properties are determined by determining the amount of polymer produced in each stage (which can be determined by analysis of unreacted gas, etc.) The physical properties of the polymer extracted after each stage can be measured, and the physical properties of the polymer produced at each stage can be determined based on the additivity.

In addition, in the polyethylene of the present invention, when the ethylene polymer (I) and the ethylene polymer (II) are used, in addition to the above characteristics, the following characteristics (vii) must be satisfied: Is preferred. The characteristic (vii) is as follows.
Characteristic (vii): Mw (I) / Mn (I) measured by MFR (I) and GPC in ethylene polymer (I), HLMFR (II) and GPC in ethylene polymer (II) Mw (II) / Mn (II) to be measured and the content (% by weight) α of the ethylene polymer (II) with respect to the total amount satisfy the relationship (A) below.
(Mw (I) / Mn (I)) ² × (Mw (II) / Mn (II)) ² × 1 / log (MFR (I)) × −1 / log (HLMFR (II)) × (1 + α / (1-α))> 500 (A)

The formula (A) described in the characteristic (vii) is a relational expression indicating the ease of mixing (homogeneity) between the ethylene polymer (I) and the ethylene polymer (II). In (A), the molecular weight distribution of each component is wide, the value of MFR or HLMFR of each component is brought close to each other, and the value increases as the ratio of each component approaches 1: 1. The generation of gel is reduced, which is preferable. If the molecular weight is 500 or less, the high molecular weight component is not mixed uniformly, so that it may become a polymer gel and the appearance may be poor.
Here, the evaluation of homogeneity was performed by cutting out a 5 mm × 5 × 0.4 mmt test piece from a 0.4 mm-thick molded sheet prepared by compression molding in accordance with JIS K6922-2, and centering it in an environment of 170 ° C. A sheet sample in which a 3 mm × 3 × 0.4 mmt portion is biaxially stretched to 6 mm × 6 can be prepared, and the determination can be made based on the state of the irregularity on the sheet sample.

  The ethylene used in the ethylene-based polymer (I) and the ethylene-based polymer (II) may be ethylene produced from crude oil derived from ordinary fossil raw materials, or may be ethylene derived from plants. . Examples of the plant-derived ethylene and polyethylene include ethylene and polymers thereof described in JP-T 2010-511634. Plant-derived ethylene and its polymers have the property of carbon neutral (does not use fossil raw materials and does not lead to an increase in carbon dioxide in the atmosphere), and can provide environmentally friendly products.

The above-mentioned polyethylene for pipes and joints can be formed into a desired molded product by pelletizing by mechanical melt mixing with a pelletizer, homogenizer or the like according to a conventional method, and then molding with various molding machines.
In addition, polyethylene for pipes and joints obtained by the above method, according to conventional methods, in addition to other olefin polymers and rubbers, antioxidants, ultraviolet absorbers, light stabilizers, lubricants, antistatic agents, Known additives such as an antifogging agent, an antiblocking agent, a processing aid, a color pigment, a crosslinking agent, a foaming agent, an inorganic or organic filler, and a flame retardant can be blended.
As additives, for example, one or more antioxidants (phenolic, phosphorus, sulfur), lubricants, antistatic agents, light stabilizers, ultraviolet absorbers, and the like can be used in combination as appropriate. As filler, calcium carbonate, talc, metal powder (aluminum, copper, iron, lead, etc.), silica, diatomaceous earth, alumina, gypsum, mica, clay, asbestos, graphite, carbon black, titanium oxide, etc. can be used. Of these, calcium carbonate, talc and mica are preferably used. In any case, the polyethylene resin composition can be blended with various additives as necessary and kneaded with a kneading extruder, a Banbury mixer, or the like to obtain a molding material.

In the present invention, in order to further accelerate the crystallization rate of polyethylene for pipes and joints, it is also an effective technique to use a nucleating agent.
As the nucleating agent, generally known nucleating agents can be used, and general organic or inorganic nucleating agents can be used. For example, dibenzylidene sorbitol or a derivative thereof, an organic phosphoric acid compound or a metal salt thereof, an aromatic sulfonate or a metal salt thereof, an organic carboxylic acid or a metal salt thereof, a rosin acid partial metal salt, an inorganic fine particle such as talc, an imide Amides, quinacridone quinones, or mixtures thereof.
Among them, a dibenzylidene sorbitol derivative, an organic phosphate metal salt, an organic carboxylic acid metal salt, and the like are preferable because they are excellent in transparency.
Specific examples of the dibenzylidene sorbitol derivative include 1,3: 2,4-bis (o-3,4-dimethylbenzylidene) sorbitol and 1,3: 2,4-bis (o-2,4-dimethylbenzylidene). Sorbitol, 1,3: 2,4-bis (o-4-ethylbenzylidene) sorbitol, 1,3: 2,4-bis (o-4-chlorobenzylidene) sorbitol, 1,3: 2,4-dibenzylidene Sorbitol is mentioned, and specific examples of the metal salt of benzoic acid include hydroxy-di (t-butylbenzoic acid) aluminum.

  When the nucleating agent is blended with the polyethylene of the present invention, the blending amount of the nucleating agent is preferably 0.01 to 5 parts by weight, more preferably 0.01 to 3 parts by weight, and still more preferably 100 parts by weight of polyethylene. Is 0.01 to 1 part by weight, particularly preferably 0.01 to 0.5 part by weight. If the nucleating agent is less than 0.01 parts by weight, the effect of improving the high-speed moldability is not sufficient. On the other hand, if it exceeds 5 parts by weight, there is a problem that the nucleating agent is likely to aggregate and form a lump.

4). Molded body The pipe and the polyethylene for joints of the present invention are used as raw materials to be molded mainly by an injection molding method, an extrusion molding method, etc., and various molded products are obtained.
Since the polyethylene of the present invention satisfies the above characteristics, it is sufficient for pipe quality standards, for example, long-term resistance under internal pressure, and high resistance to SCG under stress concentration due to notch shape, etc. They have a performance that is greatly improved compared to conventional PE100 materials, and these can be manufactured with high productivity by making the molding cycle high cycle, so the performance is excellent. In addition, it is a cost-effective molded body.
Therefore, the polyethylene for pipes and joints of the present invention is suitable for gas pipes, water distribution pipes and their joints, and particularly suitable for polyethylene pipes for water distribution and joints thereof.

5. Aspect (1)
In the present invention, one of preferable embodiments includes those satisfying the following characteristics. That is, the polyethylene of aspect (1) of the present invention has a high load melt flow rate (HLMFR (W), JIS K7210, temperature 190 ° C., load 21.60 kg) of 5 to 35 g / 10 min and a density of 0.00. 950 to 0.960 g / cm ³ , the peak top time in isothermal crystallization at 121.5 ° C. measured with a differential scanning calorimeter (DSC) is 180 seconds or less, and a full notch creep test (80 ° C., It is preferable that the breaking time in (measured at 5 MPa) is 300 hours or more and the flexural modulus (23 ° C.) is 1100 MPa or more.
And it is preferable that the polyethylene of aspect (1) of this invention contains the ethylene polymer (II) specified below. That is, the ethylene-based polymer (II) of this embodiment has a high load melt flow rate (HLMFR (II), a temperature of 190 ° C., a load of 21.60 kg) of 0.05 to 0.5 g / 10 minutes, and HLMFR ( II) (unit: g / 10 min) and the weight average molecular weight (Mw (II)) measured by gel permeation chromatography (GPC) preferably satisfy the following relationship (1).
log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +6.0 (1)

In the polyethylene of embodiment (1) of the present invention, HLMFR (W), density, peak top time in isothermal crystallization at 121.5 ° C. measured with a differential scanning calorimeter (DSC), full notch creep test (80 ° C. The break time and the flexural modulus (23 ° C.) in 5 MPa (measured at 5 MPa) are as described above, and particularly as follows.
That is, if the HLMFR (W) is less than 5 g / 10 minutes, the extrusion load increases and there is a risk of causing poor extrusion. May decrease. HLMFR (W) is preferably 7 g / 10 min or more, more preferably 9 g / 10 min or more, on the other hand, preferably 30 g / 10 min or less, more preferably 25 g / 10 min or less.
Further, if the density is less than 0.945 g / cm ³ , the pressure resistance may be reduced. On the other hand, if the density is more than 0.960 g / cm ³ , long-term durability, particularly SCG using FNCT as an index may be reduced. There is. Density is preferably, 0.948 g / cm ³ or more, more preferably, 0.954 g / cm ³ or more, whereas, preferably, 0.958 g / cm ³ or less, more preferably, 0.957 g / cm ³ or less It is.
In addition, if the peak top time in isothermal crystallization at 121.5 ° C. measured by a differential scanning calorimeter (DSC) is longer than 360 seconds, it may take a long time to take out the product and the molding cycle may be lowered. Is 60 seconds or more because it must be a polymer design that satisfies the properties of the polyethylene of the present invention. The peak top time is more preferably 300 seconds or less, and particularly preferably 180 seconds or less.
Further, if the rupture time in the full notch creep test (measured at 80 ° C. and 5 MPa) is less than 300 hours, the SCG resistance may be lowered and the product may be damaged during long-term use. 2500 hours because it must have a polymer design that satisfies the properties. The breaking time is more preferably 400 hours or more, and particularly preferably 500 hours or more.
Further, if the flexural modulus (23 ° C.) is less than 1100 MPa, the pressure resistance may be lowered due to insufficient rigidity depending on the application. is there. The flexural modulus is more preferably 1150 MPa or more, and particularly preferably 1200 MPa or more.

  Due to the polyethylene of aspect (1) of the present invention, the crystallization time is short, and in both the injection molding method and the extrusion molding method, it is possible to mold at a high cycle, and the moldability and dimensional stability are excellent. In particular, it is useful for pressure pipes such as water distribution pipes because it can be made into a pipe and joint polyethylene excellent in durability and a molded product thereof.

6). Aspect (2)
In the present invention, one of preferable embodiments includes those satisfying the following characteristics. That is, the polyethylene of the aspect (2) of the present invention has a high load melt flow rate (HLMFR (W), JIS K7210, temperature 190 ° C., load 21.60 kg) of more than 15 to 35 g / 10 minutes and a density of 0. 945 to 0.954 g / cm ³ , the breaking time in a full notch creep test (measured at 80 ° C. and 5 MPa) is 300 hours or more, and 121.5 ° C. measured by a differential scanning calorimeter (DSC). It is preferable that the peak top time in isothermal crystallization is 180 seconds or less and the flexural modulus (23 ° C.) is 950 MPa or more.
And it is preferable that the polyethylene of aspect (2) of this invention contains the ethylene polymer (I) specified below and ethylene polymer (II). That is, in this embodiment, the ethylene-based polymer (I) is polymerized using 55 to 64% by weight using a metallocene-based catalyst containing Ti, Zr or Hf, and a high load melt flow rate (HLMFR (II), JIS K7210, temperature 190 ° C., load 21.60 kg) is 0.1 to 0.5 g / 10 minutes, and the density of the ethylene-based polymer (II) 36 to 45 is 0.915 to 0.930 g / cm ^3. It is preferable to contain a weight%.

In the polyethylene of the aspect (2) of the present invention, HLMFR (W) is more than 15 to 35 g / 10 minutes, preferably 17 to 25 g / 10 minutes, and more preferably 17 to 23 g / 10 minutes.
When HLMFR (W) is 15 g / 10 min or less, the molecular weight increases, and in some cases, moldability may not be ensured due to a decrease in fluidity. Moreover, when higher than this range, there exists a possibility that long-term durability, especially SCG which uses FNCT as a parameter | index may fall.

Moreover, in the polyethylene of the aspect (2) of the present invention, the density is 0.945 to 0.954 g / cm ³ . If the density is less than 0.945 g / cm ³ , the flexural modulus decreases, and as a result, the rigidity of the material is insufficient and the pressure resistance may be decreased. On the other hand, when the density exceeds 0.954 g / cm ³ , long-term durability, particularly SCG using FNCT as an index may be lowered in some cases.

Moreover, in the polyethylene of the aspect (2) of the present invention, the breaking time in the full notch creep test (FNCT, measured at 80 ° C., 5 MPa) is 300 hours or more. Preferably, it is 400 hours or more, More preferably, it is 500 hours or more.
If the above time is less than 300 hours, the durability of the molded product may be inferior.

Moreover, in the polyethylene of the aspect (2) of the present invention, the peak top time in isothermal crystallization at 121.5 ° C. measured by a differential scanning calorimeter (DSC) is 180 seconds or less. When this value exceeds 180 seconds, the crystallization time becomes longer, the molding speed is delayed, and the molding cycle may be lengthened.
This value can be adjusted by the density and molecular weight of polyethylene. For example, when the polyethylene is composed of an ethylene polymer (I) and an ethylene polymer (II), the density, molecular weight and blending amount of the ethylene polymer (II) can be adjusted.
Outside the above range, for example, when the polyethylene is composed of an ethylene polymer (I) and an ethylene polymer (II), the HLMFR of the ethylene polymer (II) is high, the density is low, and the blending amount is small The peak top time in isothermal crystallization at 121.5 ° C. measured by a differential scanning calorimeter (DSC) of polyethylene exceeds 180 seconds. In addition, outside this range, similarly, for example, when the polyethylene is composed of an ethylene polymer (I) and an ethylene polymer (II), the HLMFR of the ethylene polymer (II) is low, the density is high, If the amount is too large, the rigidity, moldability, long-term durability, and other requirements may not be satisfied.

  In the polyethylene according to the aspect (2) of the present invention, the flexural modulus is 950 MPa or more. When the flexural modulus is less than 950 MPa, the flexural modulus decreases, resulting in insufficient material rigidity, which may reduce pressure resistance. Although the upper limit of a bending elastic modulus is not specifically limited, Usually, it is 1300 MPa or less.

The polyethylene of the embodiment (2) of the present invention satisfies the above characteristics and is particularly suitable for pipe and joint applications.
For example, in the case of polyethylene pipes for water distribution and joints thereof, it is desired to use the same materials as polyethylene pipes (pipe) and joints according to requests for various standards. Due to the above properties, the polyethylene for pipes and joints of the present invention sufficiently meets the quality standards for pipes, for example, long-term durability under internal pressure, and high resistance to SCG due to stress concentration due to notch shape. In addition, they have significantly improved performance compared to the conventional PE100 material, and have physical properties such as durability required for pipes and joints, and in particular, high fluidity and short crystallization time. In both the injection molding and extrusion molding methods, excellent productivity is exhibited.
Specifically, in injection molding, the flowability is high and the crystallization time is short, so the time for taking out the molded product is shortened, high cycle is possible and productivity is improved. Further, there is an effect that post-shrinkage hardly occurs and dimensional stability is good. Furthermore, in extrusion molding, the high fluidity reduces the motor load, and the high crystallization speed shortens the cooling time, enabling the production cycle to be increased, and at the same time the pipe product extruded in the molten state. Since the crystallization speed is high, there is an effect that resistance to pipe surface scratches generated during molding is improved and the pipe surface appearance is improved.
That is, the polyethylene of the aspect (2) of the present invention has the above-mentioned properties of high fluidity and a short crystallization time, and thus has an economically effective point particularly in both injection molding and extrusion molding. The resin composition is suitable for pipes and joints.
Furthermore, since the molded article using the polyethylene of the aspect (2) of the present invention has a performance exceeding the conventional product in the pipe quality standard, it is suitable as a polyethylene pipe and a joint.

  Since the polyethylene of the aspect (2) of the present invention is easy to adjust the polyethylene of the aspect (2) of the present invention and becomes a preferable polyethylene for pipes and joints, the ethylene polymer (I) is polymerized with a metallocene catalyst. A specific amount of the ethylene polymer (II) having a specific property is preferably blended. Furthermore, it is preferable that a specific amount of the ethylene polymer (II) having a specific property polymerized with a metallocene catalyst is blended with the specific property ethylene polymer (I).

In the aspect (2) of the present invention, the ethylene polymer (I) has a melt flow rate (MFR) of 50 to 200 g / 10 min at a temperature of 190 ° C. and a load of 2.16 Kg, and a density of 0.955 to 0. It is preferably 975 g / cm ³ . More preferably, the ethylene polymer (I) has an MFR of 80 to 150 g / 10 min and a density of 0.966 to 0.973 g / cm ³ .

The MFR of the ethylene polymer (I) is preferably 50 to 200 g / 10 minutes, more preferably 80 to 150 g / 10 minutes. When the MFR is less than 50 g / 10 min, the molecular weight increases, the fluidity decreases, and the moldability cannot be ensured. On the other hand, when the MFR exceeds 200 g / 10 min, the impact resistance may be lowered or the SCG may be lowered.
Moreover, it is preferable that the density of ethylene-type polymer (I) is 0.955-0.975 g / cm < ³ >, More preferably, it is 0.966-0.973 g / cm < ³ >. If the density is less than 0.955 g / cm ³ , the pressure resistance of the final polyethylene may be reduced. On the other hand, when the density exceeds 0.975 g / cm ³ , it becomes difficult to produce polyethylene, and even if it can be produced, the final polyethylene may have a markedly reduced impact resistance.
In addition, the ethylene polymer (I) is as described in detail above.

The polyethylene of the aspect (2) of the present invention is easy to adjust the polyethylene of the aspect (2) of the present invention, and is a preferable polyethylene for pipes and joints. An ethylene-based polymer that is polymerized using a metallocene-based catalyst containing Ti, Zr or Hf, has an HLMFR of 0.1 to 0.5 g / 10 min, and a density of 0.915 to 0.930 g / cm ³ It is preferable to contain 36 to 45% by weight of polymer (II).

  The HLMFR of the ethylene polymer (II) is 0.1 g / 10 min or more and 0.5 g / 10 min or less, preferably 0.1 to 0.4 g / 10 min, more preferably 0.2 to 0.3 g. / 10 minutes. If this HLMFR is less than 0.1 g / 10 min, in the final polyethylene, the HLMFR cannot be within the specified range, and the fluidity may be lowered. On the other hand, when the HLMFR exceeds 0.5 g / 10 min, in the final polyethylene, long-term durability, in particular, SCG with FNCT as an index decreases, and the crystallization rate also decreases, and can be measured by DSC. The isothermal crystallization time at 121.5 ° C. exceeds 180 seconds, with the result that the molding cycle may be reduced.

The density of the ethylene-based polymer (II) is 0.915 to 0.930 g / cm ³ , preferably 0.915 to 0.925 g / cm ³ , more preferably 0.920 to 0.925 g / cm ^3. It is. If the density is less than 0.915 g / cm ³ , the density range in the final polyethylene cannot be achieved, and the flexural modulus decreases, resulting in insufficient rigidity of the material, which may reduce pressure resistance. On the other hand, when the density exceeds 0.930 g / cm ³ , the long-term durability of the final polyethylene, particularly SCG using FNCT as an index may be lowered.

  The ethylene polymer (II) satisfying this relationship has a long-chain branched structure, and when used together with the ethylene polymer (I), the crystallization rate can be extremely effectively increased. The same effects as when the nucleating agent is added can be exhibited, the crystallization time can be shortened, high-speed molding and high cycle as polyethylene for pipes and joints can be achieved, and durability can also be improved.

In conventional polyethylene, methods such as adding a substance that acts as a crystal nucleating agent have been attempted to increase the crystallization speed. As a result of studying polyethylene that sufficiently improves both physical properties such as, specific characteristics, that is, HLMFR, density, rupture time in full notch creep test (FNCT, measured at 80 ° C., 5 MPa), differential scanning calorimeter (DSC) While the peak top time and the flexural modulus (23 ° C.) in isothermal crystallization at 121.5 ° C. measured by the above are specific values, polyethylene maintains excellent physical properties such as mechanical strength while maintaining crystal properties. It is conceivable that the forming speed can be sufficiently improved and the forming speed can be improved.
In particular, by using the ethylene-based polymer (II) according to the embodiment (2) of the present invention together with the ethylene-based polymer (I), all of the above characteristics are satisfied, while maintaining excellent physical properties such as mechanical strength. Thus, the crystallization speed can be sufficiently improved, and the molding speed can be improved.

  Preferably, the ethylene-based polymer (II) is an embodiment of the present invention by using the one satisfying the following formula (1), more preferably formula (2), particularly preferably formula (3). This is a preferable polyethylene for pipes and joints that exhibits the remarkable effect of (2) and has a sufficiently improved crystallization rate.

log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +6.0 Formula (1)
log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +5.9 Formula (2)
log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +5.8 Formula (3)

However, HLMFR (II) is a high load melt flow rate (unit: g / 10 minutes) at a temperature of 190 ° C. and a load of 21.6 Kg, and Mw (II) was measured by gel permeation chromatography (GPC). Weight average molecular weight.
Here, the technical meanings of the above formulas (1) to (3) are as described above.

Examples of the ethylene polymer (II) having a long chain branch structure according to the embodiment (2) of the present invention include a polymer having about one long chain branch per 10,000 carbon chains. For example, it can be confirmed by ¹³ C-NMR measurement. The ethylene-based polymer having a long chain branched structure can be produced by polymerization using a chromium catalyst such as a Philips catalyst or a metallocene catalyst as a single site catalyst as a polymerization catalyst.
In addition, as the ethylene polymer (II) having a long-chain branched structure, polyethylene having a terminal vinyl group (macromonomer) is generated by chain transfer to ethylene, and a long-chain is obtained through copolymerization of the macromonomer and ethylene. A polymer having a branched structure can be obtained.
Among the metallocene catalysts, a catalyst having a metallocene complex having a specific structure is preferable, and a metallocene catalyst having a cyclopentadienyl ring and a heterocyclic aromatic group or a metallocene catalyst having a cyclopentadienyl ring and a fluorenyl ring is particularly preferable.

The blending amount of the ethylene polymer (II) is 36 to 45% by weight with respect to 55 to 64% by weight of the ethylene polymer (I), preferably 55 to 62% by weight of the ethylene polymer (I). It is 38 to 45 weight%, More preferably, it is 38 to 40 weight% with respect to 60 to 62 weight% of ethylene-type polymer (I). If the blending amount of the ethylene polymer (II) is less than 36% by weight, the long-term durability of the polyethylene of the embodiment (2) of the present invention, particularly SCG using FNCT as an index, may be lowered. On the other hand, if it exceeds 45% by weight, the MFR and density of the polyethylene of the embodiment (2) of the present invention are lowered, and there is a possibility that the polymer is lowered in fluidity, rigidity and pressure resistance.
In addition, the ethylene polymer (II) is as described above in detail.

The aspect (2) of the present invention is excellent in durability, particularly in pipe and joint applications, has a short crystallization time and high fluidity, and is molded at a high cycle in both the injection molding method and the extrusion molding method. In addition, it is a polyethylene for pipes and joints and a molded body thereof excellent in the dimensional stability of the injection-molded product and the pipe surface appearance.
Therefore, it is suitable for gas pipes, water distribution pipes and their joints, especially suitable for polyethylene pipes for water distribution and their joints, pipe quality standards, for example, long-term resistance under internal pressure, notch shape, etc. The high resistance to SCG under stress concentration due to the above is sufficiently matched, and the performance is greatly improved compared to the conventional PE100 material, and it has high fluidity and high crystallization speed. There is an effect that it is possible. Therefore, it has the effect of exhibiting excellent productivity in both injection molding and extrusion molding methods as well as performance exceeding conventional PE100.
Specifically, in injection molding, the fluidity is high and the crystallization time is short, which shortens the time for taking out a molded product, enables high cycle, improves productivity, and is a thick product. However, there is an effect that post-shrinkage hardly occurs and dimensional stability is good. Furthermore, in extrusion molding, since the motor load is reduced due to high fluidity, the screw rotation speed can be further increased, and the cooling time is shortened due to the high crystallization speed, enabling the production cycle to be increased, At the same time, since the crystallization speed of the pipe extruded in the molten state is high, there is an effect that resistance to pipe surface scratches generated during molding is improved and the pipe surface appearance is improved.
Moreover, the molded article using the polyethylene of the aspect (2) of the present invention has performance exceeding the quality standard for pipes, and can be molded at high speed, and is economically advantageous for pipes and joints for water distribution. Can be suitably used.
Using the polyethylene of aspect (2) of the present invention as a raw material, it is molded mainly by an injection molding method, an extrusion molding method, etc., and various molded products are obtained.
Since the polyethylene of the aspect (2) of the present invention satisfies the above-mentioned characteristics, it is suitable for pipe quality standards, for example, long-term durability in a state where internal pressure is applied, SCG under stress concentration due to notch shape, etc. They are highly compatible with high resistance, have performance that is significantly improved compared to conventional PE100 materials, and can be manufactured with high productivity by making the molding cycle high cycle. Therefore, the molded article has excellent performance and is advantageous in terms of cost.
Therefore, the molded article of polyethylene according to the aspect (2) of the present invention can be suitably used particularly for polyethylene pipes for water distribution and joints that require such characteristics.

7). Aspect (3)
In the present invention, one of preferable embodiments includes those satisfying the following characteristics. That is, the polyethylene of aspect (3) of the present invention has a high load melt flow rate (HLMFR (W), JIS K7210, temperature 190 ° C., load 21.60 kg) of 7 to 15 g / 10 min and a density of 0.00. 945 to 0.954 g / cm ³ , the rupture time in a full notch creep test (measured at 80 ° C. and 5 MPa) is 500 hours or more, and measured at 121.5 ° C. measured with a differential scanning calorimeter (DSC). The peak top time in isothermal crystallization is preferably 180 seconds or less, and the flexural modulus (23 ° C.) is preferably 950 MPa or more.
And the polyethylene of aspect (3) of this invention is a high load melt flow rate (HLMFR (II), JIS K7210, temperature 190 degreeC, load 21.60 kg with respect to ethylene-type polymer (I) 50-60 weight%. ) Is 0.05 to 0.5 g / 10 min, the density is 0.915 to 0.930 g / cm ³ , HLMFR (II) (unit: g / 10 min) and gel permeation chromatography (GPC) It is preferable that the weight average molecular weight (Mw (II)) measured in (1) contains 40 to 50% by weight of an ethylene polymer (II) that satisfies the following relationship (1).
log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +6.0 (1)

In the polyethylene of the aspect (3) of the present invention, the high load melt flow rate (HLMFR (W), JIS K7210, temperature 190 ° C., load 21.60 kg) is 7 to 15 g / 10 minutes, preferably 8 to 13 g. / 10 minutes, more preferably 9-12 g / 10 minutes.
When HLMFR (W) is lower than this range, the molecular weight may increase in some cases, and the moldability may not be ensured due to a decrease in fluidity. Moreover, when higher than this range, there exists a possibility that long-term durability, especially SCG which uses FNCT as a parameter | index may fall.

Moreover, in the polyethylene of the aspect (3) of the present invention, the density is 0.945 to 0.954 g / cm ³ . If the density is less than 0.945 g / cm ³ , the flexural modulus decreases, and as a result, the rigidity of the material is insufficient and the pressure resistance may be decreased. On the other hand, when the density exceeds 0.954 g / cm ³ , long-term durability, particularly SCG using FNCT as an index may be lowered in some cases.

Moreover, in the polyethylene of the aspect (3) of the present invention, the breaking time in the full notch creep test (FNCT, measured at 80 ° C., 5 MPa) is 500 hours or more. Preferably, it is 600 hours or more, and more preferably 700 hours or more.
If the above time is less than 500 hours, the molded article may be inferior in durability when stress concentration such as scratches or stone contact occurs, which is not preferable.

  In the polyethylene of the embodiment (3) of the present invention, the peak top time in isothermal crystallization at 121.5 ° C. measured by a differential scanning calorimeter (DSC) is 180 seconds or less. When this value exceeds 180 seconds, the crystallization time becomes longer, the molding speed is delayed, and the molding cycle may be lengthened.

  Moreover, in the polyethylene of the aspect (3) of the present invention, the flexural modulus is 950 MPa or more. When the flexural modulus is less than 950 MPa, the flexural modulus decreases, resulting in insufficient material rigidity, which may reduce pressure resistance. Although the upper limit of a bending elastic modulus is not specifically limited, Usually, it is 1300 MPa or less.

Since the polyethylene of aspect (3) of the present invention satisfies the above characteristics, it is particularly suitable for pipe and joint applications.
For example, in the case of polyethylene pipes for water distribution and joints thereof, it is desired to use the same materials as polyethylene pipes (pipe) and joints according to requests for various standards. Due to the above properties, the polyethylene of aspect (3) of the present invention is sufficient for pipe quality standards, for example, long-term durability under internal pressure, high resistance to SCG under stress concentration due to notch shape, etc. They have performance that is significantly improved compared to conventional PE100 materials, and have physical properties such as durability required for pipes and joints, and short crystallization time, so that injection molding and extrusion molding In both molding methods, excellent productivity is exhibited.
Specifically, in injection molding, the flowability is high and the crystallization time is short, so the time for taking out the molded product is shortened, high cycle is possible and productivity is improved. Further, there is an effect that post-shrinkage hardly occurs and dimensional stability is good. Furthermore, in extrusion molding, the cooling time is shortened due to the high crystallization speed, enabling the production cycle to be improved, and at the same time, the crystallization speed of the pipe product extruded in the molten state is high, so that the pipe surface damage that occurs during molding There is an effect that the resistance to the pipe is improved and the pipe surface appearance is improved. In addition, the polymer gel, which occurs in the shape of a lump and causes poor appearance, has the effect of suppressing the aggregation of the high molecular weight components and improving the pipe surface appearance by uniformly mixing the components constituting the polyethylene. is there.
That is, the polyethylene according to the aspect (3) of the present invention has the above-mentioned property that the crystallization time is short, and particularly has an economically effective point in both injection molding and extrusion molding. It became a suitable resin composition.
Furthermore, since the molded article using the polyethylene of the aspect (3) of the present invention has a performance exceeding the conventional product in the pipe quality standard, it is suitable as a polyethylene pipe and a joint.

  Since the polyethylene of the aspect (3) of the present invention is easy to adjust the polyethylene of the aspect (3) of the present invention and becomes a preferable polyethylene for pipes and joints, the ethylene polymer (I) is polymerized with a metallocene catalyst. A specific amount of the ethylene polymer (II) having a specific property is preferably blended. Furthermore, it is preferable that a specific amount of the ethylene polymer (II) having a specific property polymerized with a metallocene catalyst is blended with the specific property ethylene polymer (I).

In this case, it is preferable that the polyethylene of the aspect (3) of the present invention further satisfies the following characteristic (vii) in addition to the above characteristic.
Characteristic (vii): Mw (I) / Mn (I) measured by MFR (I) and GPC in ethylene polymer (I), HLMFR (II) and GPC in ethylene polymer (II) Mw (II) / Mn (II) to be measured and the content (% by weight) α of the ethylene polymer (II) with respect to the total amount satisfy the relationship (A) below.
(Mw (I) / Mn (I)) ² × (Mw (II) / Mn (II)) ² × 1 / log (MFR (I)) × −1 / log (HLMFR (II)) × (1 + α / (1-α))> 500 (A)
The formula (A) described in the characteristic (vii) is a relational expression indicating the ease of mixing (homogeneity) between the ethylene polymer (I) and the ethylene polymer (II). In (A), the molecular weight distribution of each component is wide, the value of MFR or HLMFR of each component is brought close to each other, and the value increases as the ratio of each component approaches 1: 1. The generation of gel is reduced, which is preferable. If the molecular weight is 500 or less, the high molecular weight component is not mixed uniformly, so that it may become a polymer gel and the appearance may be poor.
Here, the evaluation of homogeneity was performed by cutting out a 5 mm × 5 × 0.4 mmt test piece from a 0.4 mm-thick molded sheet prepared by compression molding in accordance with JIS K6922-2, and centering it in an environment of 170 ° C. A sheet sample in which a 3 mm × 3 × 0.4 mmt portion is biaxially stretched to 6 mm × 6 can be prepared, and the determination can be made based on the state of the irregularity on the sheet sample.

In the aspect (3) of the present invention, the ethylene polymer (I) has a melt flow rate (MFR (I)) of 50 to 200 g / 10 min at a temperature of 190 ° C. and a load of 2.16 Kg, and a density of 0.8. It is preferably 955 to 0.975 g / cm ³ . More preferably, the ethylene polymer (I) has an MFR (I) of 80 to 150 g / 10 min and a density of 0.966 to 0.973 g / cm ³ .

The MFR (I) of the ethylene polymer (I) is preferably 50 to 200 g / 10 minutes, and more preferably 80 to 150 g / 10 minutes. When the MFR is less than 50 g / 10 min, the molecular weight increases, the fluidity decreases, and the moldability cannot be ensured. On the other hand, when the MFR exceeds 200 g / 10 min, the impact resistance may be lowered or the SCG may be lowered.
Moreover, it is preferable that the density of ethylene-type polymer (I) is 0.955-0.975 g / cm < ³ >, More preferably, it is 0.966-0.973 g / cm < ³ >. If the density is less than 0.955 g / cm ³ , the pressure resistance of the final polyethylene may be reduced. On the other hand, when the density exceeds 0.975 g / cm ³ , it becomes difficult to produce polyethylene, and even if it can be produced, the final polyethylene may have a markedly reduced impact resistance.
In addition, the ethylene polymer (I) is as described in detail above.

  The polyethylene of embodiment (3) of the present invention is an ethylene polymer polymerized using a metallocene catalyst containing Ti, Zr, or Hf with respect to 50 to 60% by weight of the ethylene polymer (I). II) is preferably contained in an amount of 40 to 50% by weight.

  The MFR (II) of the ethylene polymer (II) is 0.05 g / 10 min or more and 0.5 g / 10 min or less, preferably 0.05 to 0.35 g / 10 min, more preferably 0.1 to 0.1 g. The range is 0.2 g / 10 minutes. If this MFR is less than 0.05 g / 10 min, in the final polyethylene, the MFR cannot be within the specified range, the fluidity is lowered, and the mixing with the ethylene polymer (I) is poor. It is inferior in uniformity. On the other hand, when the MFR (II) exceeds 0.5 g / 10 min, in the final polyethylene, long-term durability, in particular, SCG with FNCT as an index decreases, and the crystallization rate also decreases, and DSC The isothermal crystallization time at 121.5 ° C., which can be measured by the method, exceeds 180 seconds, and as a result, the molding cycle may be lowered.

The density of the ethylene-based polymer (II) is 0.915 to 0.930 g / cm ³ , preferably 0.920 to 0.925 g / cm ³ , more preferably 0.920 to 0.922 g / cm ^3. It is. If the density is less than 0.915 g / cm ³ , the density range in the final polyethylene cannot be achieved, and the flexural modulus decreases, resulting in insufficient rigidity of the material, which may reduce pressure resistance. On the other hand, when the density exceeds 0.930 g / cm ³ , the long-term durability of the final polyethylene, particularly SCG using FNCT as an index may be lowered.

  The ethylene polymer (II) satisfying this relationship has a long-chain branched structure, and when used together with the ethylene polymer (I), the crystallization rate can be extremely effectively increased. The same effects as when the nucleating agent is added can be exhibited, the crystallization time can be shortened, high-speed molding and high cycle as polyethylene for pipes and joints can be achieved, and durability can also be improved.

The ethylene polymer (II) is preferably subjected to gel permeation chromatography (GPC) with a high load melt flow rate (HLMFR (II)) (unit: g / 10 min) at a temperature of 190 ° C. and a load of 21.6 kg. The weight average molecular weight (Mw (II)) measured in this way satisfies the relationship (1) below.
log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +6.0 Formula (1)

In conventional ethylene-based polymers, methods such as adding a substance that acts as a crystal nucleating agent have been tried to increase the crystallization speed. As a result of studying polyethylene that sufficiently improves both physical properties such as mechanical strength, the use of the ethylene polymer (II) according to the present invention together with the ethylene polymer composition (I) provides excellent mechanical strength. It is considered that the crystallization speed can be sufficiently improved while maintaining the physical properties such as, and the molding speed can be improved.
Preferably, the ethylene polymer (II) satisfying the relationship (1) described above, preferably the following relationship (2), more preferably the ethylene polymer satisfying the following relationship (3) ( According to II), the remarkable effect of the aspect (3) of the present invention is exhibited, and a preferable polyethylene for pipes and joints is obtained.
log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +5.9 Formula (2)
log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +5.8 Formula (3)

Here, the technical meaning of the above formula (1) indicates that the fluidity is low in proportion to the weight average molecular weight, that is, the HLMFR is small, and this indicates that this ethylene polymer (II) Is an ethylene polymer having a long chain branching structure, and having a long chain branching structure exhibiting a specific HLMFR with respect to a predetermined Mw.
In the formulas (1) to (3), the value of the intercept (“6.0” in the case of the formula (1)) is an index indicating the development of the long-chain branched structure. The fact that the relational expression of HLMFR is established indicates that it has a more developed long chain branching structure. If the development of the long chain branching structure is insufficient, the crystal nucleus material effect may be weakened and the crystallization rate may not be sufficiently improved.
In the technical field to which the aspect (3) of the present invention belongs, various methods are known for measuring an ethylene polymer having a long-chain branched structure. Such a polymer is also included in the ethylene polymer having a long-chain branched structure. Of the ethylene-based polymers having a long-chain branched structure, those satisfying the formula of the present invention are suitable as those having a specific long-chain branched structure.
Specific examples of the long-chain branched structure that controls the molding speed include a star-shaped branched polymer and a comb-shaped branched polymer, but are not limited thereto.

Examples of the ethylene polymer (II) having a long chain branched structure according to the embodiment (3) of the present invention include a polymer having about one long chain branch per 10,000 carbon chains. Can be confirmed by, for example, ¹³ C-NMR measurement. The ethylene-based polymer having a long chain branched structure can be produced by polymerization using a chromium catalyst such as a Philips catalyst or a metallocene catalyst as a single site catalyst as a polymerization catalyst.
In addition, as the ethylene polymer (II) having a long-chain branched structure, polyethylene having a terminal vinyl group (macromonomer) is generated by chain transfer to ethylene, and a long-chain is obtained through copolymerization of the macromonomer and ethylene. A polymer having a branched structure can be obtained.
Among the metallocene catalysts, a catalyst having a metallocene complex having a specific structure is preferable, and a metallocene catalyst having a cyclopentadienyl ring and a heterocyclic aromatic group or a metallocene catalyst having a cyclopentadienyl ring and a fluorenyl ring is particularly preferable.

The blending amount of the ethylene polymer (II) is 40 to 50% by weight with respect to 50 to 60% by weight of the ethylene polymer (I), preferably 55 to 60% by weight with respect to the ethylene polymer (I). 40 to 45% by weight. If the blending amount of the ethylene polymer (II) is less than 40% by weight, the long-term durability of the polyethylene of the aspect (3) of the present invention, particularly SCG using FNCT as an index may be lowered. On the other hand, if it exceeds 50% by weight, the MFR and density of the polyethylene of the embodiment (3) of the present invention are lowered, and there is a possibility that the polymer is lowered in fluidity, rigidity and pressure resistance.
In addition, the ethylene polymer (II) is as described above in detail.

In more detail, the polyethylene and the molded product thereof according to the aspect (3) of the present invention, particularly in pipe and joint applications, have a short crystallization time, excellent moldability, and both injection molding and extrusion molding methods. It is a polyethylene for pipes and joints and a molded body thereof that can be molded in a high cycle, has excellent dimensional stability, scratch resistance, and homogeneity, and has extremely high long-term durability.
The polyethylene for pipes and joints and the molded body thereof according to the aspect (3) of the present invention are suitable for gas pipes, water pipes and their joints, and particularly suitable for polyethylene pipes for water distribution and joints thereof. It fully meets the criteria, for example, long-term resistance to internal pressure, high stress crack resistance, low temperature notched impact strength and high resistance to rapid crack growth, especially long-term durability is significantly higher than conventional PE100 material It is improved, and since the crystallization speed is high, there is an effect that high-speed molding is possible. Therefore, it has performance superior to that of conventional PE100, exhibits excellent productivity in both the injection molding and extrusion molding methods, and controls the blending ratio, molecular weight, and molecular weight distribution of each component. In order to suppress aggregation of the molecular weight component (polymer gel), there is an effect that there is no appearance defect due to the high molecular weight gel.
The above "long-term durability" refers to excellent environmental stress crack resistance, hot internal pressure creep resistance of the pipe or low-speed crack extension characteristics, etc., and the polyethylene resin composition for pipes and joints of the present invention is In particular, the value by a full notch creep test (FNCT) is high, and there is an effect that the environmental stress crack resistance is extremely excellent.
As for moldability, specifically, in injection molding, the crystallization time is short, which shortens the time for taking out a molded product, enables high cycle and improves productivity. Further, there is an effect that post-shrinkage hardly occurs and dimensional stability is good. Furthermore, in extrusion molding, the cooling time is shortened due to the high crystallization speed, enabling the production cycle to be increased, and at the same time the crystallization speed of the pipe extruded in the molten state is high, so that the pipe surface scratches that occur during molding There is an effect that the resistance to the pipe is improved and the pipe surface appearance is improved.
In addition, the polymer gel, which occurs in the shape of a lump and causes poor appearance, has the effect of suppressing the aggregation of the high molecular weight components and improving the pipe surface appearance by uniformly mixing the components constituting the polyethylene. is there.
Furthermore, the molded product using the polyethylene of the aspect (3) of the present invention has performance exceeding the quality standard for pipes, in particular, has a high value by FNCT which is slow crack growth and extremely long-term durability. High-speed molding is possible, and it can be suitably used as an economically advantageous pipe and joint for water distribution.
Using the polyethylene of the aspect (3) of the present invention as a raw material, it is molded mainly by an injection molding method, an extrusion molding method or the like to obtain various molded products.
Since the polyethylene of the aspect (3) of the present invention satisfies the above-mentioned characteristics, it is suitable for pipe quality standards, for example, long-term durability in a state where internal pressure is applied, SCG under stress concentration due to notch shape, etc. It fully matches the high resistance, has a performance that is significantly improved compared to conventional PE100 materials, and can be manufactured with high productivity by making the molding cycle high cycle, In addition, since the appearance of the pipe is good, the molded product is advantageous in terms of cost because it has excellent performance and can be expected to reduce production off-products.
Therefore, the molded article of polyethylene according to the aspect (3) of the present invention can be suitably used particularly for polyethylene pipes and joints for water distribution that require such characteristics.

8). Aspect (4)
In the present invention, one of preferable embodiments includes those satisfying the following characteristics. That is, the polyethylene of aspect (4) of the present invention has a high load melt flow rate (HLMFR (W), JIS K7210, temperature 190 ° C., load 21.60 kg) of 5 to 20 g / 10 min and a density of 0.00. More than 954 to 0.960 g / cm ³ , the breaking time in a full notch creep test (measured at 80 ° C. and 5 MPa) is 300 hours or more, and at 121.5 ° C. measured by a differential scanning calorimeter (DSC) It is preferable that the peak top time in isothermal crystallization is 180 seconds or less and the tensile yield stress is 27 MPa or more.
The polyethylene according to the aspect (4) of the present invention is polymerized using a metallocene catalyst containing Ti, Zr or Hf with respect to 60 to 65% by weight of the ethylene polymer (I), and a high load melt flow rate is obtained. (HLMFR (II), JIS K7210, temperature 190 ° C., load 21.60 kg) is 0.01 to 0.5 g / 10 min, the density is 0.915 to 0.930 g / cm ³ , and HLMFR (II ) (Unit: g / 10 min) and ethylene-based polymer (II) 35 to 35 having a weight average molecular weight (Mw (II)) measured by gel permeation chromatography (GPC) satisfying the following relationship (1): It is preferable to contain 40 weight%.
log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +6.0 (1)

In the polyethylene of embodiment (4) of the present invention, HLMFR (W) is 5 to 20 g / 10 minutes, preferably 7 to 15 g / 10 minutes, and more preferably 8 to 12 g / 10 minutes.
When HLMFR (W) is lower than this range, the molecular weight increases, and the moldability may not be ensured due to a decrease in fluidity. Moreover, when higher than this range, there exists a possibility that long-term durability, especially SCG which uses FNCT as a parameter | index may fall.

Moreover, in the polyethylene of the aspect (4) of the present invention, the density is 0.954 to 0.960 g / cm ³ . If the density is 0.954 g / cm ³ or less, the flexural modulus may be lowered in some cases, resulting in insufficient material rigidity and reduced pressure resistance. On the other hand, when the density exceeds 0.960 g / cm ³ , long-term durability, particularly SCG using FNCT as an index may be lowered.

Moreover, in the polyethylene of the aspect (4) of the present invention, the breaking time in the full notch creep test (FNCT, measured at 80 ° C., 5 MPa) is 300 hours or more. Preferably, it is 400 hours or more, More preferably, it is 500 hours or more.
If the above time is less than 300 hours, the durability of the molded product may be inferior.

  Moreover, in the polyethylene of the aspect (4) of the present invention, the peak top time in isothermal crystallization at 121.5 ° C. measured by a differential scanning calorimeter (DSC) is 180 seconds or less. When this value exceeds 180 seconds, the crystallization time becomes longer, the molding speed is delayed, and the molding cycle may be lengthened.

Moreover, in the polyethylene of the aspect (4) of the present invention, the tensile yield stress is 27 MPa or more. When this value is 27 MPa or less, the pressure resistance is insufficient when used in an environment with high pressure, or when the thickness of the pipe is reduced, and there is a risk of ductile fracture and rupture.
This value can be adjusted by the density of polyethylene. For example, when the polyethylene is composed of an ethylene polymer (I) and an ethylene polymer (II), the density and blending amount of the ethylene polymer (I) and the ethylene polymer (II) can be adjusted. .
If the tensile yield stress is 27 or more, for example, assuming that the MRS is about 12.5 MPa, the pipe thickness design can be reduced by about 18% compared to the PE100 material with an MRS of about 10 MPa. It is done.

The polyethylene of aspect (4) of the present invention satisfies the above characteristics and is particularly suitable for pipe and joint applications.
For example, in the case of polyethylene pipes for water distribution and joints thereof, it is desired to use the same materials as polyethylene pipes (pipe) and joints according to requests for various standards. Due to the above properties, the polyethylene for pipes and joints of the present invention sufficiently meets the quality standards for pipes, for example, long-term durability under internal pressure, and high resistance to SCG due to stress concentration due to notch shape. In addition, they have significantly improved performance compared to conventional PE100 materials, and have physical properties such as durability required for pipes and joints, and short crystallization time, so both injection molding and extrusion molding In this molding method, excellent productivity is exhibited.
Specifically, in injection molding, the flowability is high and the crystallization time is short, so the time for taking out the molded product is shortened, high cycle is possible and productivity is improved. Further, there is an effect that post-shrinkage hardly occurs and dimensional stability is good. Furthermore, in extrusion molding, the cooling time is shortened due to the high crystallization speed, enabling the production cycle to be improved, and at the same time, the crystallization speed of the pipe product extruded in the molten state is high, so that the pipe surface damage that occurs during molding There is an effect that the resistance to the pipe is improved and the pipe surface appearance is improved.
That is, the polyethylene of the aspect (4) of the present invention has the characteristics of high pressure resistance and short crystallization time, and particularly has both economically effective points in both injection molding and extrusion molding. Polyethylene suitable for pipes and joints.
Furthermore, the molded product using the polyethylene for pipes and joints of the present invention is suitable as a polyethylene pipe and joint because it has a performance exceeding that of conventional products in the quality standards for pipes.
Moreover, since the polyethylene thin-walled polyethylene pipe of the aspect (4) of the present invention uses the polyethylene of the aspect (4) of the present invention, the thickness of the pipe is reduced, the weight of the pipe is reduced, and the service life is improved. The application location can be expanded.

Since the polyethylene of the aspect (4) of the present invention is easy to adjust the polyethylene of the aspect (4) of the present invention and becomes a preferable polyethylene for pipes and joints, the ethylene polymer (I) is polymerized with a metallocene catalyst. A specific amount of the ethylene polymer (II) having a specific property is preferably blended. Furthermore, it is preferable that a specific amount of the ethylene polymer (II) having a specific property polymerized with a metallocene catalyst is blended with the specific property ethylene polymer (I).
In the aspect (4) of the present invention, the ethylene polymer (I) has a melt flow rate (MFR) of 50 to 200 g / 10 min at a temperature of 190 ° C. and a load of 2.16 Kg, and a density of 0.960 to 0. It is preferably 975 g / cm ³ . More preferably, the ethylene polymer (I) has an MFR of 80 to 150 g / 10 min and a density of 0.966 to 0.973 g / cm ³ .

The MFR of the ethylene polymer (I) is preferably 50 to 200 g / 10 minutes, more preferably 80 to 150 g / 10 minutes. When the MFR is less than 50 g / 10 min, the molecular weight increases, the fluidity decreases, and the moldability cannot be ensured. On the other hand, when the MFR exceeds 200 g / 10 min, the impact resistance may be lowered or the SCG may be lowered.
Moreover, it is preferable that the density of ethylene-type polymer (I) is 0.960-0.975 g / cm < ³ >, More preferably, it is 0.966-0.973 g / cm < ³ >. If the density is less than 0.960 g / cm ³ , the pressure resistance of the final polyethylene may be reduced. On the other hand, when the density exceeds 0.975 g / cm ³ , it becomes difficult to produce polyethylene, and even if it can be produced, the final polyethylene may have a markedly reduced impact resistance.
In addition, the ethylene polymer (I) is as described in detail above.

The polyethylene of the aspect (4) of the present invention is easy to adjust the polyethylene of the aspect (4) of the present invention, and becomes a preferable polyethylene for pipes and joints, so that the ethylene polymer (I) is 60 to 65% by weight. An ethylene-based polymer that is polymerized using a metallocene-based catalyst containing Ti, Zr or Hf, has an HLMFR of 0.01 to 0.5 g / 10 min, and a density of 0.915 to 0.930 g / cm ³ It is preferable that the polymer (II) is contained in an amount of 35 to 40% by weight.

  The HLMFR (II) of the ethylene polymer (II) is 0.01 g / 10 min or more and 0.5 g / 10 min or less, preferably 0.05 to 0.2 g / 10 min, more preferably 0.1 to 10 g. The range is 0.15 g / 10 minutes. If this HLMFR is less than 0.01 g / 10 min, in the final polyethylene, the HLMFR cannot be within the specified range, and the fluidity may be lowered. On the other hand, when the HLMFR exceeds 0.5 g / 10 min, in the final polyethylene, long-term durability, in particular, SCG with FNCT as an index decreases, and the crystallization rate also decreases, and can be measured by DSC. The isothermal crystallization time at 121.5 ° C. exceeds 180 seconds, with the result that the molding cycle may be reduced.

The density of the ethylene-based polymer (II) is 0.915 to 0.930 g / cm ³ , preferably 0.915 to 0.925 g / cm ³ , more preferably 0.920 to 0.925 g / cm ^3. It is. If the density is less than 0.915 g / cm ³ , the density range in the final polyethylene cannot be achieved, and the flexural modulus decreases, resulting in insufficient rigidity of the material, which may reduce pressure resistance. On the other hand, when the density exceeds 0.930 g / cm ³ , the long-term durability of the final polyethylene, particularly SCG using FNCT as an index may be lowered.

  In conventional ethylene-based polymers, methods such as adding a substance that acts as a crystal nucleating agent have been tried to increase the crystallization speed. As a result of studying an ethylene polymer that sufficiently improves both physical properties such as mechanical strength, the use of the ethylene polymer (II) according to the present invention together with the ethylene polymer composition (I) is excellent. It is considered that the crystallization speed can be sufficiently improved while maintaining the physical properties such as mechanical strength, and the molding speed can be improved.

  Preferably, the ethylene-based polymer (II) uses the following formula (1), more preferably the formula (2), particularly preferably the one satisfying the formula (3). This is a preferable polyethylene for pipes and joints that exhibits an effect and has a sufficiently improved crystallization rate.

log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +6.0 Formula (1)
log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +5.9 Formula (2)
log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +5.8 Formula (3)

  However, HLMFR (II) is a high load melt flow rate (unit: g / 10 min) at a temperature of 190 ° C. and a load of 21.6 Kg, and Mw is a weight average molecular weight measured by gel permeation chromatography (GPC). It is.

Here, the technical meaning of the above formula (1) indicates that the fluidity is low in proportion to the weight average molecular weight, that is, the HLMFR is small, and this indicates that this ethylene polymer (II) Is an ethylene-based polymer having a long-chain branching structure that exhibits a specific HLMFR (II) with respect to a predetermined Mw (II).
In the formulas (1) to (3), the value of the intercept (“6.0” in the case of the formula (1)) is an index indicating the development of the long-chain branching structure. The fact that the relational expression between the molecular weight and HLMFR is established indicates that the structure has a more developed long chain branching structure. If the development of the long chain branching structure is insufficient, the crystal nucleus material effect may be weakened and the crystallization rate may not be sufficiently improved.
In the technical field to which the present invention pertains, various methods are known for measuring an ethylene polymer having a long-chain branched structure. For example, polymers that show rise in viscosity in the measurement of elongational viscosity are also long-chain polymers. Included in ethylene polymers having a branched structure. Of the ethylene polymers having a long-chain branched structure, those satisfying the formula of the embodiment (4) of the present invention are suitable as those having a specific long-chain branched structure.
Specific examples of the long-chain branched structure that controls the molding speed include a star-shaped branched polymer and a comb-shaped branched polymer, but are not limited thereto.

Examples of the ethylene-based polymer (II) having a long-chain branch structure according to the embodiment (4) of the present invention include a polymer having about one long-chain branch per 10,000 carbon chains. For example, it can be confirmed by ¹³ C-NMR measurement. The ethylene-based polymer having a long chain branched structure can be produced by polymerization using a chromium catalyst such as a Philips catalyst or a metallocene catalyst as a single site catalyst as a polymerization catalyst.
In addition, as the ethylene polymer (II) having a long-chain branched structure, polyethylene having a terminal vinyl group (macromonomer) is generated by chain transfer to ethylene, and a long-chain is obtained through copolymerization of the macromonomer and ethylene. A polymer having a branched structure can be obtained.
Among the metallocene catalysts, a catalyst having a metallocene complex having a specific structure is preferable, and a metallocene catalyst having a cyclopentadienyl ring and a heterocyclic aromatic group or a metallocene catalyst having a cyclopentadienyl ring and a fluorenyl ring is particularly preferable.

The blending amount of the ethylene polymer (II) is 35 to 40% by weight with respect to the ethylene polymer (I) 60 to 65% by weight, preferably 60 to 63% by weight with respect to the ethylene polymer (I). 37 to 40% by weight, more preferably 37 to 39% by weight with respect to 61 to 63% by weight of the ethylene polymer (I). If the blending amount of the ethylene polymer (II) is less than 35% by weight, the long-term durability of the polyethylene of the embodiment (4) of the present invention, particularly SCG using FNCT as an index may be lowered. On the other hand, if it exceeds 40% by weight, the MFR and density of the polyethylene of the aspect (4) of the present invention are lowered, and there is a possibility that the polymer is lowered in fluidity, rigidity and pressure resistance.
In addition, the ethylene polymer (II) is as described above in detail.
The polyethylene of aspect (4) of the present invention is used as a raw material to be molded mainly by an injection molding method, an extrusion molding method, or the like to obtain various molded products.

The polyethylene of the aspect (4) of the present invention and the molded product thereof and the thin-walled polyethylene pipe are more specifically, particularly in pipes and joints, have high pressure resistance, excellent long-term durability, short crystallization time, injection In both the molding method and the extrusion molding method, high cycle molding is possible, and the dimensional stability of the injection molded product and the pipe surface appearance are excellent. Regarding the tube.
The polyethylene according to the aspect (4) of the present invention is suitable for gas pipes, water distribution pipes and their joints, particularly suitable for polyethylene pipes for water distribution and their joints, and pipe quality standards such as internal pressure are applied. Long-term resistance in the state, high resistance to SCG under stress concentration due to notch shape, etc., sufficiently improved performance compared to conventional PE100 material, and high crystallization speed Therefore, there is an effect that high-speed molding is possible. Therefore, in particular, with respect to the durability, the performance is far superior to that of the conventional PE 100, and excellent productivity is exhibited in both the injection molding and the extrusion molding methods.
Specifically, in injection molding, the short crystallization time shortens the time for taking out a molded product, enables a high cycle, and improves productivity. Is less likely to occur and has the effect of good dimensional stability. Furthermore, in extrusion molding, the cooling time is shortened due to the high crystallization speed, enabling the production cycle to be increased, and at the same time, the crystallization speed of the pipe product extruded in the molten state is high, so the pipe surface generated during molding There is an effect that resistance to scratches is improved and the pipe surface appearance is improved.
In addition, the molded article using the polyethylene according to the aspect (4) of the present invention has performance far exceeding the conventional quality standards for pipes in terms of durability, so that the thickness of the pipe is reduced, the weight of the pipe is reduced, and the service life is increased. There is an effect that it is possible to improve the number of applications and to expand the application location.
And since the thin polyethylene pipe of the aspect (4) of the present invention has excellent performance and productivity as described above, the weight of the pipe is reduced, the service life is improved, the application area is expanded, and the earthquake resistance is improved. It can be improved, etc., and has the effect of being economically advantageous.

Accordingly, since the polyethylene according to the aspect (4) of the present invention satisfies the above characteristics, it is particularly excellent in pressure resistance, and is based on quality standards for pipes, for example, long-term resistance in a state where internal pressure is applied, notch shape, etc. It fully matches the high resistance to SCG under stress concentration, and has a performance that is greatly improved compared to the conventional PE100 material. Therefore, the molded product is excellent in performance and cost-effective.
Therefore, the molded article of polyethylene according to aspect (4) of the present invention can be suitably used particularly for polyethylene pipes for water distribution and joints that require such characteristics. In particular, since it is extremely excellent in pressure resistance and excellent in long-term durability, it can be made thinner than before, so that it can be particularly suitably used as a thin polyethylene pipe.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples as long as the gist thereof is not exceeded.

1. Measurement method The measurement methods used in the examples are as follows.
(1) Melt flow rate (HLMFR) at a temperature of 190 ° C. and a load of 21.6 kg:
The measurement was performed according to JIS K7210.
(2) Melt flow rate (MFR) at a temperature of 190 ° C. and a load of 2.16 kg:
The measurement was performed according to JIS K7210.
(3) Density:
It measured based on JIS K6922-1,2: 1997.

(4) Rupture time in full notch creep test (measured at 80 ° C. and 5 MPa):
The measurement was performed at 80 ° C. and 5 MPa in accordance with the all-around notch tensile creep test of JIS K6774 (1995) Appendix 1. The test piece was cut from a compression molded sheet with a thickness of 6 mm prepared under the conditions of JIS K6922-2 (1997) Table 2, and notched all around (test piece thickness 6 mm, notch depth 1 mm, full circumference). It was used. As a test solution for immersing the sample, a 1% aqueous solution of sodium alkyl sulfate was used.
(5) Crystallization time (peak top time in isothermal crystallization at 121.5 ° C. measured with a differential scanning calorimeter (DSC)):
The sample was allowed to stand at 190 ° C. for 5 minutes using DSC-7 manufactured by Perkin Elmer, and then cooled to 121.5 ° C. at a rate of 120 ° C./min. The peak top was detected and measured when crystallization was completed at an isothermal temperature of 121.5 ° C.
(6) Flexural modulus:
The test piece was cut out from the compression molded sheet with a thickness of 4 mm prepared under the conditions of JIS K6922-2 (1997) Table 2, and measured in accordance with JIS K6922-2 (1997).

(7) Measurement of molecular weight by gel permeation chromatography (GPC) (weight average molecular weight Mw):
It measured by the gel permeation chromatography (GPC) of the following conditions.
Apparatus: WATERS 150C
Column: 3 AD80M / S manufactured by Showa Denko KK Measurement temperature: 140 ° C
Concentration: 1 mg / 1 ml
Solvent: o-dichlorobenzene Calculation of molecular weight and column calibration were performed according to the following method.
GPC chromatographic data was loaded into a computer at a frequency of 1 point / second, and data processing was performed according to the description in Chapter 4 of “Size Exclusion Chromatography” published by Sadao Mori and Kyoritsu Publishing Co., and Mw value was calculated.
The column was calibrated by monodisperse polystyrene (S-7300, S-3900, S-1950, S-1460, S-1010, S-565, S-152, S-66.0, S-28 manufactured by Showa Denko KK. .5, S-5.05), a series of monodisperse polystyrene measurements using each 0.2 mg / ml solution of n-eicosane and n-tetracontane and the logarithm of their elution peak time and molecular weight A calibration curve was obtained by fitting the relationship with a quartic polynomial.
In addition, the molecular weight (MPS) of polystyrene was converted into the molecular weight (MPE) of polyethylene using the following formula.
MPE = 0.468 × MPS

(8) Homogeneity evaluation:
A 50 mm × 50 × 0.4 mmt test piece was cut out from a 0.4 mm thick molded sheet prepared by compression molding in accordance with JIS K6922-2, and 4 mm sides of the sample were chucked by 1 mm under an environment of 170 ° C. The state of irregularities on the sheet sample in which the 30 mm × 30 × 0.4 mmt portion was biaxially stretched to 60 mm × 60 was judged.
The case where there was no fluff was marked with ◎, the case where a small amount of fluff was present was marked with ◯, and the case where the flute was at a level that would actually cause an appearance defect with a pipe was marked as x.

(9) Tensile yield stress:
The test piece was cut according to JIS K7161 by cutting out a 1B multipurpose test piece shape from a compression molded sheet with a thickness of 4 mm prepared under the conditions of JIS K6922-2 (1997) (Table 2).

(10) Pipe surface appearance (scratch resistance during molding):
The pipe surface was visually observed and judged according to the following criteria.
○: No deep / wide stripe-like scratches ×: Deep / wide stripe-like scratches

(11) Evaluation:
(I) Example I
A pipe having an outer diameter of 32 mmφ and a wall thickness of 3 mmt was molded at a molding temperature of 200 ° C., a cooling temperature of about 20 ° C., and an air gap of 30 mm, and its suitability was comprehensively evaluated.
○: Both crystallization speed and pipe physical properties are good, and high-speed moldability and pipe surface appearance are also good.
X: Slow acceleration of crystallization, high-speed moldability / pipe surface appearance is not good, HLMFR (W) is not in a preferable range, and moldability is not particularly excellent.

(Ii) Example II
A pipe having an outer diameter of 32 mmφ and a wall thickness of 3 mmt was molded at a molding temperature of 200 ° C., a cooling temperature of about 20 ° C., and an air gap of 30 mm, and its suitability was comprehensively evaluated.
○: Both crystallization speed and pipe physical properties are good, and high-speed moldability and pipe surface appearance are also good.
X: The balance between the acceleration of crystallization and the physical properties of the pipe is poor, which is insufficient as the polyethylene of the present invention.

(Iii) Example III
A pipe having an outer diameter of 32 mmφ and a wall thickness of 3 mmt was molded at a molding temperature of 200 ° C., a cooling temperature of about 20 ° C., and an air gap of 30 mm, and its suitability was comprehensively evaluated.
○: Both crystallization speed and pipe physical properties are good, and high-speed moldability and pipe surface appearance are also good.
X: The balance between the acceleration of crystallization and the physical properties of the pipe is poor, and the HLMFR (W) is low and the moldability is inferior, which is insufficient as the polyethylene of the present invention.

(Iv) Example IV
A pipe having an outer diameter of 32 mmφ and a wall thickness of 3 mmt was molded at a molding temperature of 200 ° C., a cooling temperature of about 20 ° C., and an air gap of 30 mm, and its suitability was comprehensively evaluated.
○: Both crystallization speed and pipe physical properties are good, and high-speed moldability and pipe surface appearance are also good.
X: The balance between crystallization acceleration and pipe physical properties is poor, which is insufficient as the polyethylene of the present invention.

2. Materials used (1) Ethylene polymer (I): (E1) and (E38)
<Manufacture of Ziegler catalyst>
40 ml of a co-ground product obtained by co-grinding 20 g of commercially available magnesium ethylate, 1.64 g (12.3 mmol) of granular aluminum trichloride and 2.40 g (8.81 mmol) of diphenyldiethoxysilane Of heptane and 10.0 g (52.7 mmol) of titanium tetrachloride were added dropwise at room temperature, the temperature was raised to 90 ° C., and stirring was continued for 90 minutes. By washing with hexane at room temperature, 15.6 g of a solid catalyst was obtained.
<Polymerization>
A 2.0 L autoclave thoroughly purged with nitrogen was charged with 1.0 mmol of triisobutylaluminum (0.50 mol / L hexane solution) and 1.0 L of isobutane, and the internal temperature was raised to 90 ° C. After further charging hydrogen, 20 mg of solid catalyst was introduced under pressure with ethylene, and the hydrogen concentration in the autoclave gas phase was measured while maintaining the partial pressure of ethylene. Continued. Thus, 185 g of a polymer (E1) which is an ethylene polymer (I) was obtained. Moreover, it polymerized according to said polymerization method, and manufactured the polymer (E38). The physical property values of (E1) and (E38) are shown in Tables 1 to 4.

(2) Example I
(I) Ethylene polymer (II): (E2) to (E7), (E10), (E15) and (E22)
<Production of polymer with metallocene catalyst>
Metallocene catalyst described in Example 3 of JP-T-2002-535339, dimethylsilylenebis {1,1 ′-[2- (2-furyl) -4,5-dimethyl-cyclopentadienyl]} zirconium dichloride The ethylene polymer (II) was produced by the following method using

<Preparation of supported catalyst>
To 13.4 ml of toluene, 8.5 ml of a toluene solution of methylalumoxane (Albemarle, Al concentration: 2.93 mol / L) and dimethylsilylenebis {1,1 ′-[2- (2-furyl) -4,5- Dimethyl-cyclopentadienyl]} zirconium dichloride (70.6 mg) was added, and the mixture was stirred at room temperature for 30 minutes in the dark.
Next, 5.0 g of SiO ₂ (manufactured by GRACE, 948) previously calcined at 400 ° C. for 8 hours in a nitrogen atmosphere was added to the toluene solution, and the mixture was stirred at 40 ° C. for 1 hour. Thereafter, vacuum drying was performed while maintaining 40 ° C. to obtain a solid catalyst. The obtained solid catalyst was slurried with hexane and used for ethylene polymerization.

<Ethylene polymerization>
4 ml of a hexane dilution of triethylaluminum (Al concentration 0.1 mol / L) was added to an autoclave with an internal volume of 1.5 L purged with nitrogen, and 800 ml of isobutane was introduced. The internal temperature of the autoclave was raised to 80 ° C., and ethylene was introduced so that the ethylene partial pressure was 1.4 MPa. 7 ml of a solid catalyst hexane slurry (20 mg / ml) was introduced into an autoclave to initiate polymerization. During polymerization, the ethylene partial pressure was kept constant at 80 ° C. Further, in order to keep the hydrogen concentration during the polymerization constant, the hydrogen concentration in the gas phase part of the autoclave was measured, and the polymerization was continued while appropriately adding 1-hexene and hydrogen. After 1 hour, the reaction was stopped by purging the internal pressure of the autoclave and isobutane.
As a result, 75 g of polymer (E2), which is an ethylene polymer (II), was recovered.
Similarly, the polymers of (E2), (E10), (E15), and (E22) were produced by adjusting the ethylene partial pressure, the hydrogen concentration, and the 1-hexene amount.
Moreover, it polymerized according to said polymerization method using cyclopentadienyl-type metallocene catalysts other than said metallocene-type catalyst, and manufactured the polymers of ethylene polymer (E3)-(E7).

(3) Example II
(I) Ethylene polymer (II): (E8) to (E18)
<Production of polymer with metallocene catalyst>
Metallocene catalyst described in Example 3 of JP-T-2002-535339, dimethylsilylenebis {1,1 ′-[2- (2-furyl) -4,5-dimethyl-cyclopentadienyl]} zirconium dichloride The ethylene polymer (II) was produced by the following method using

<Preparation of supported catalyst>
To 13.4 ml of toluene, 8.5 ml of a toluene solution of methylalumoxane (Albemarle, Al concentration: 2.93 mol / L) and dimethylsilylenebis {1,1 ′-[2- (2-furyl) -4,5- Dimethyl-cyclopentadienyl]} zirconium dichloride (70.6 mg) was added, and the mixture was stirred at room temperature for 30 minutes in the dark.
Next, 5.0 g of SiO ₂ (manufactured by GRACE, 948) previously calcined at 400 ° C. for 8 hours in a nitrogen atmosphere was added to the toluene solution, and the mixture was stirred at 40 ° C. for 1 hour. Thereafter, vacuum drying was performed while maintaining 40 ° C. to obtain a solid catalyst. The obtained solid catalyst was slurried with hexane and used for ethylene polymerization.

<Ethylene polymerization>
4 ml of a hexane dilution of triethylaluminum (Al concentration 0.1 mol / L) was added to an autoclave with an internal volume of 1.5 L purged with nitrogen, and 800 ml of isobutane was introduced. The internal temperature of the autoclave was raised to 80 ° C., and ethylene was introduced so that the ethylene partial pressure was 1.4 MPa. 7 ml of a solid catalyst hexane slurry (20 mg / ml) was introduced into an autoclave to initiate polymerization. During polymerization, the ethylene partial pressure was kept constant at 80 ° C. Further, in order to keep the hydrogen concentration during the polymerization constant, the hydrogen concentration in the gas phase part of the autoclave was measured, and the polymerization was continued while appropriately adding 1-hexene and hydrogen. After 1 hour, the reaction was stopped by purging the internal pressure of the autoclave and isobutane.
As a result, 75 g of the polymer (E8) which is an ethylene polymer (II) was recovered.
Similarly, polymers (E9) to (E15) were produced by adjusting the ethylene partial pressure, the hydrogen concentration, and the 1-hexene amount.
In addition, by using a cyclopentadienyl-based metallocene catalyst other than the above-mentioned metallocene-based catalyst, polymerization is performed according to the above-described polymerization method, and the polymers of the ethylene-based polymers (E16), (E17) and (E18) Manufactured.

(Ii) Ethylene polymer (II): (E19) to (E21)
What was manufactured with the Ziegler catalyst was used as ethylene copolymer (II).

(4) Example III
(I) Ethylene polymer (II): (E22) to (E27) and (E30)
<Production of polymer with metallocene catalyst>
Metallocene catalyst described in Example 3 of JP-T-2002-535339, dimethylsilylenebis {1,1 ′-[2- (2-furyl) -4,5-dimethyl-cyclopentadienyl]} zirconium dichloride The ethylene polymer (II) was produced by the following method using

<Preparation of supported catalyst>
To 13.4 ml of toluene, 8.5 ml of a toluene solution of methylalumoxane (Albemarle, Al concentration: 2.93 mol / L) and dimethylsilylenebis {1,1 ′-[2- (2-furyl) -4,5- Dimethyl-cyclopentadienyl]} zirconium dichloride (70.6 mg) was added, and the mixture was stirred at room temperature for 30 minutes in the dark.
Next, 5.0 g of SiO ₂ (manufactured by GRACE, 948) previously calcined at 400 ° C. for 8 hours in a nitrogen atmosphere was added to the toluene solution, and the mixture was stirred at 40 ° C. for 1 hour. Thereafter, vacuum drying was performed while maintaining 40 ° C. to obtain a solid catalyst. The obtained solid catalyst was slurried with hexane and used for ethylene polymerization.

<Ethylene polymerization>
4 ml of a hexane dilution of triethylaluminum (Al concentration 0.1 mol / L) was added to an autoclave with an internal volume of 1.5 L purged with nitrogen, and 800 ml of isobutane was introduced. The internal temperature of the autoclave was raised to 80 ° C., and ethylene was introduced so that the ethylene partial pressure was 1.4 MPa. 7 ml of a solid catalyst hexane slurry (20 mg / ml) was introduced into an autoclave to initiate polymerization. During polymerization, the ethylene partial pressure was kept constant at 80 ° C. Further, in order to keep the hydrogen concentration during the polymerization constant, the hydrogen concentration in the gas phase part of the autoclave was measured, and the polymerization was continued while appropriately adding 1-hexene and hydrogen. After 1 hour, the reaction was stopped by purging the internal pressure of the autoclave and isobutane.
As a result, 75 g of the polymer (E22) which is an ethylene polymer (II) was recovered.
Similarly, the polymers of (E23) to (E27) were produced by adjusting the ethylene partial pressure, the hydrogen concentration, and the 1-hexene amount.
Moreover, it polymerized according to said polymerization method using cyclopentadienyl-type metallocene catalysts other than said metallocene-type catalyst, and manufactured the polymer of the ethylene-type polymer (E30).
(Ii) Ethylene polymer (II): (E28) and (E29)
What was manufactured with the Ziegler catalyst was used as ethylene-type polymer (II).

(5) Example IV
(I) Ethylene polymer (II): (E31) to (E35)
<Production of polymer with metallocene catalyst>
Metallocene catalyst described in Example 3 of JP-T-2002-535339, dimethylsilylenebis {1,1 ′-[2- (2-furyl) -4,5-dimethyl-cyclopentadienyl]} zirconium dichloride The ethylene polymer (II) was produced by the following method using

<Preparation of supported catalyst>
To 13.4 ml of toluene, 8.5 ml of a toluene solution of methylalumoxane (Albemarle, Al concentration: 2.93 mol / L) and dimethylsilylenebis {1,1 ′-[2- (2-furyl) -4,5- Dimethyl-cyclopentadienyl]} zirconium dichloride (70.6 mg) was added, and the mixture was stirred at room temperature for 30 minutes in the dark.
Next, 5.0 g of SiO ₂ (manufactured by GRACE, 948) previously calcined at 400 ° C. for 8 hours in a nitrogen atmosphere was added to the toluene solution, and the mixture was stirred at 40 ° C. for 1 hour. Thereafter, vacuum drying was performed while maintaining 40 ° C. to obtain a solid catalyst. The obtained solid catalyst was slurried with hexane and used for ethylene polymerization.

<Ethylene polymerization>
4 ml of a hexane dilution of triethylaluminum (Al concentration 0.1 mol / L) was added to an autoclave with an internal volume of 1.5 L purged with nitrogen, and 800 ml of isobutane was introduced. The internal temperature of the autoclave was raised to 80 ° C., and ethylene was introduced so that the ethylene partial pressure was 1.4 MPa. 7 ml of a solid catalyst hexane slurry (20 mg / ml) was introduced into an autoclave to initiate polymerization. During polymerization, the ethylene partial pressure was kept constant at 80 ° C. Further, in order to keep the hydrogen concentration during the polymerization constant, the hydrogen concentration in the gas phase part of the autoclave was measured, and the polymerization was continued while appropriately adding 1-hexene and hydrogen. After 1 hour, the reaction was stopped by purging the internal pressure of the autoclave and isobutane.
As a result, 75 g of polymer (E31) which was an ethylene polymer (II) was recovered.
Similarly, polymers (E32) to (E35) were produced by adjusting the ethylene partial pressure, the hydrogen concentration, and the 1-hexene amount.

(Ii) Ethylene polymer (II): (E36) and (E37)
What was manufactured with the Ziegler catalyst was used as ethylene-type polymer (II).

3. Example I
[Example (I-1)]
<Manufacture of polyethylene resin composition>
The ethylene polymer (I) (E1) and the ethylene polymer (II) (E2) were melt-mixed in the proportions shown in Table 1 to produce polyethylene.
The physical properties and evaluation results of the resin composition are shown in Table 1. The obtained polyethylene was excellent in mechanical properties such as fluidity, flexural modulus and long-term durability, and also had a short crystallization time and excellent molding high cycle property.

[Examples (I-2) to (I-7), Reference Examples (I-1) to (I-5)]
Conditions were set so that the composition shown in Table 1 was obtained, and the ethylene polymer (I) and the ethylene polymer (II) were melted and mixed in the proportions shown in Table 1 to produce polyethylene in the same manner as in Example 1. did. The evaluation results of the obtained polyethylene are shown in Table 1.

[Evaluation]
As described above, when Examples (I-1) to (I-7) and Reference Examples (I-1) to (I-5) are compared from the results shown in Table 1, the pipes and joints of the present invention are used. Polyethylene that does not satisfy the specific requirements for polyethylene is inferior to the polyethylenes of Examples (I-1) to (I-7) in terms of the balance between moldability and durability.
Compared to these reference examples, the polyethylene for pipes and joints according to the present invention and the molded body thereof have a good balance of moldability and durability as shown in Examples (I-1) to (I-7). It was confirmed.

4). Example II
[Example (II-1)]
<Manufacture of polyethylene resin composition>
The ethylene polymer (I) (E1) and the ethylene polymer (II) (E8) were melt-mixed in the proportions shown in Table 2 to produce polyethylene.
The physical properties and evaluation results of the resin composition are shown in Table 2. The obtained polyethylene was excellent in mechanical properties such as fluidity, flexural modulus and long-term durability, and also had a short crystallization time and excellent molding high cycle property.

[Examples (II-2) to (II-9), Reference Examples (II-1) to (II-6)]
The conditions were set so that the composition shown in Table 2 was obtained, and the ethylene polymer (I) and the ethylene polymer (II) were melted and mixed in the proportions shown in Table 2, and the same as in Example (II-1). Polyethylene was produced. The evaluation results of the obtained polyethylene are shown in Table 2.

[Evaluation]
As described above, when Examples (II-1) to (II-9) are compared with Reference Examples (II-1) to (II-6) from the results shown in Table 2, the pipes and joints of the present invention are used. Polyethylene that does not meet the specific requirements for polyethylene is inferior to the polyethylenes of Examples (II-1) to (II-9) in terms of the balance between moldability and durability.
Compared with these reference examples, the polyethylene for pipes and joints according to the present invention and the molded body thereof have a good balance of moldability and durability as shown in Examples (II-1) to (II-9). It was confirmed.

5. Example III
[Example (III-1)]
<Manufacture of polyethylene resin composition>
The ethylene polymer (I) (E1) and the ethylene polymer (II) (E22) were melt-mixed in the proportions shown in Table 3 to produce polyethylene.
The physical properties and evaluation results of the resin composition are shown in Table 3. The obtained polyethylene was excellent in mechanical properties such as fluidity, flexural modulus, and long-term durability, and also had a short crystallization time and excellent molding high cycle property and homogeneity.

[Examples (III-2) to (III-7), Reference Examples (III-1) to (III-4)]
The conditions were set so that the composition shown in Table 3 was obtained, and the ethylene polymer (I) and the ethylene polymer (II) were melted and mixed in the proportions shown in Table 3, respectively, and the same as in Example (III-1) Polyethylene was produced. The evaluation results of the obtained polyethylene are shown in Table 3.

[Evaluation]
As described above, when Examples (III-1) to (III-7) are compared with Reference Examples (III-1) to (III-4) from the results shown in Table 3, the pipes and joints of the present invention are used. Polyethylene that does not meet the specific requirements for polyethylene is inferior to the polyethylenes of Examples (III-2) to (III-7) in terms of the balance between moldability and durability.
Compared to these reference examples, the polyethylene for pipes and joints according to the present invention and the molded body thereof have a good balance of moldability and durability as shown in Examples (III-2) to (III-7). It was confirmed.

6). Example IV
[Example (IV-1)]
<Manufacture of polyethylene resin composition>
The ethylene polymer (I) (E1) and the ethylene polymer (II) (E31) were melt-mixed in the proportions shown in Table 4 to produce polyethylene.
The physical properties and evaluation results of the resin composition are shown in Table 4. The obtained polyethylene was excellent in mechanical properties such as fluidity, tensile yield stress, and long-term durability, and also had a short crystallization time and excellent molding high cycle property.

[Examples (IV-2) to (IV-6), Reference Examples (IV-1) to (IV-4)]
The conditions were set so that the composition shown in Table 4 was obtained, and the ethylene polymer (I) and the ethylene polymer (II) were melted and mixed in the proportions shown in Table 4, respectively, as in Example (IV-1). Polyethylene was produced. The evaluation results of the obtained polyethylene are shown in Table 4.

[Evaluation]
As described above, when Examples (IV-1) to (IV-6) are compared with Reference Examples (IV-1) to (IV-4) from the results shown in Table 4, the pipes and joints of the present invention are used. Polyethylene that does not meet the specific requirements for polyethylene is inferior to the polyethylenes of Examples (IV-1) to (IV-6) in terms of the balance between moldability and durability.
Compared to these reference examples, the polyethylene for pipes and joints and the molded body thereof according to the present invention have a good balance between moldability and durability as shown in Examples (IV-1) to (IV-6). It was confirmed.

7). Comprehensive evaluation As described above, polyethylene that does not satisfy the specific requirements of the polyethylene for pipes and joints of the present invention has a short crystallization time as compared with the reference example, and in both the injection molding method and the extrusion molding method, it is a high cycle. It was confirmed that this was a polyethylene for pipes and joints and a molded body thereof excellent in moldability and dimensional stability.
Moreover, it was confirmed that the polyethylene of the specific aspect of the present invention is an excellent polyethylene for pipes and joints and a molded product thereof having both crystallization speed, homogeneity, durability and the like.

According to the present invention, it is suitable for gas pipes, water distribution pipes and their joints, particularly suitable for water supply polyethylene pipes and their joints, and is suitable for pipe quality standards, for example, long-term resistance under conditions of internal pressure. It fully matches the high resistance to SCG under stress concentration due to notch shape, etc., has significantly improved performance compared to conventional PE100 material, and has high fluidity, injection molding method and In both methods of extrusion molding, it is possible to provide a polyethylene for pipes and joints that can be molded in a high cycle.
In particular, the long-term durability is greatly improved as compared with the conventional PE100 material, and since the crystallization speed is high, there is an effect that high-speed molding is possible, and in both molding methods of injection molding and extrusion molding, It exhibits excellent productivity and has an excellent appearance that there are few pipe surface scratches, irregularities, etc., and can reduce the product off rate.
In particular, the value by FNCT, which is slow crack growth, is high, and it has a performance that greatly exceeds the above standards in terms of long-term durability, and is a molded product with excellent dimensional stability and improved product appearance and excellent performance. High cycle is possible, and it can contribute to the expansion of applications of polyethylene pipes and joints, and is advantageous in terms of productivity and cost.
In particular, it is a molded product having high durability, excellent dimensional stability, and good pipe surface appearance, which is advantageous in terms of productivity and cost.
Therefore, the polyethylene for pipes and joints according to the present invention and a molded body comprising the same are very useful in industry.

Claims (13)

A polyethylene for pipes and joints characterized by satisfying the following characteristics (i) to (iii):
Characteristic (i): High load melt flow rate (HLMFR (W), JIS K7210, temperature 190 ° C., load 21.60 kg) is 5 to 35 g / 10 min.
Characteristic (ii): The density is 0.945 to 0.960 g / cm ³ .
Characteristic (iii): The peak top time in isothermal crystallization at 121.5 ° C. measured by a differential scanning calorimeter (DSC) is 360 seconds or less. High load melt flow rate (HLMFR (II), JIS K7210, temperature 190 ° C., load 21.60 kg) is 0.01 to 0.5 g / 10 minutes with respect to 50 to 80% by weight of ethylene polymer (I). 2. The polyethylene for pipes and joints according to claim 1, comprising 20 to 50% by weight of an ethylene polymer (II) having a density of 0.915 to 0.930 g / cm ³ .   The polyethylene for pipes and joints according to claim 2, wherein the ethylene polymer (II) is polymerized using a metallocene catalyst having a cyclopentadienyl ring and a heterocyclic aromatic group. The density is 0.950-0.960 g / cm ³ , the peak top time in isothermal crystallization at 121.5 ° C. measured with a differential scanning calorimeter (DSC) is 180 seconds or less, and The pipe and joint polyethylene according to any one of claims 1 to 3, which satisfies the following characteristics (iv) and (v):
Characteristic (iv): The rupture time in a full notch creep test (measured at 80 ° C. and 5 MPa) is 300 hours or more.
Characteristic (v): Flexural modulus (23 ° C.) is 1100 MPa or more. The ethylene polymer (II) has a high load melt flow rate (HLMFR (II), JIS K7210, temperature 190 ° C., load 21.60 kg) of 0.05 to 0.5 g / 10 min, and HLMFR (II) The weight average molecular weight (Mw (II)) measured by (unit: g / 10 minutes) and gel permeation chromatography (GPC) satisfies the relationship of the following (1). The polyethylene for pipes and joints according to any one of the above.
log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +6.0 (1) High load melt flow rate (HLMFR (W), JIS K7210, temperature 190 ° C., load 21.60 kg) is more than 15 to 35 g / 10 min, density is 0.945 to 0.954 g / cm ³ , full notch The rupture time in a creep test (measured at 80 ° C. and 5 MPa) is 300 hours or more, and the peak top time in isothermal crystallization at 121.5 ° C. measured by a differential scanning calorimeter (DSC) is 180 seconds or less. The polyethylene for pipes and joints according to any one of claims 1 to 3, wherein the bending elastic modulus (23 ° C) is 950 MPa or more. Polymerized using a metallocene-based catalyst containing Ti, Zr or Hf with respect to 55 to 64% by weight of the ethylene-based polymer (I), and a high-load melt flow rate (HLMFR (II), JIS K7210, temperature 190 ° C., A load of 21.60 kg) is 0.1 to 0.5 g / 10 min, and a density is 0.915 to 0.930 g / cm ³ and contains 36 to 45% by weight of an ethylene polymer (II). The polyethylene for pipes and joints according to claim 6. High load melt flow rate (HLMFR (W), JIS K7210, temperature 190 ° C., load 21.60 kg) is 7 to 15 g / 10 min, density is 0.945 to 0.954 g / cm ³ , full notch creep The break time in the test (measured at 80 ° C. and 5 MPa) is 500 hours or more, and the peak top time in isothermal crystallization at 121.5 ° C. measured by a differential scanning calorimeter (DSC) is 180 seconds or less. The polyethylene for pipes and joints according to any one of claims 1 to 3, wherein the flexural modulus (23 ° C) is 950 MPa or more. High load melt flow rate (HLMFR (II), JIS K7210, temperature 190 ° C., load 21.60 kg) is 0.05 to 0.5 g / 10 min with respect to 50 to 60% by weight of ethylene polymer (I). The density is 0.915 to 0.930 g / cm ³ , and the weight average molecular weight (Mw (II) measured by HLMFR (II) (unit: g / 10 min) and gel permeation chromatography (GPC) is present. The polyethylene for pipes and joints according to claim 8, wherein 40) to 50% by weight of ethylene-based polymer (II) satisfying the relationship of (1) below is contained.
log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +6.0 (1) High load melt flow rate (HLMFR (W), JIS K7210, temperature 190 ° C., load 21.60 kg) is 5 to 20 g / 10 min, density is more than 0.954 to 0.960 g / cm ³ , full notch The rupture time in a creep test (measured at 80 ° C. and 5 MPa) is 300 hours or more, and the peak top time in isothermal crystallization at 121.5 ° C. measured by a differential scanning calorimeter (DSC) is 180 seconds or less. The polyethylene for pipes and joints according to any one of claims 1 to 3, further satisfying the following characteristic (vi):
Characteristic (vi): The tensile yield stress is 27 MPa or more. Polymerized by using a metallocene catalyst containing Ti, Zr or Hf with respect to 60 to 65% by weight of the ethylene polymer (I), a high load melt flow rate (HLMFR (II), JIS K7210, temperature 190 ° C., Load 21.60 kg) is 0.01 to 0.5 g / 10 min, density is 0.915 to 0.930 g / cm ³ , HLMFR (II) (unit: g / 10 min) and gel permeation The weight-average molecular weight (Mw (II)) measured by chromatography (GPC) contains from 35 to 40% by weight of an ethylene polymer (II) that satisfies the relationship (1) below. The pipe and joint polyethylene according to claim 10.
log [HLMFR (II)] ≦ −3.85 log [Mw (II) / 10000] +6.0 (1)   A molded body comprising the pipe and the joint polyethylene according to any one of claims 1 to 11.   The molded body according to claim 12, which is a pipe or a joint.