JPH0339089B2 - - Google Patents

Description

[Detailed description of the invention] The present invention has excellent impact strength and blocking resistance,
This invention relates to an ethylene/α-olefin copolymer that has good environmental stress cracking resistance, transparency, and tear resistance, and has a good balance of heat resistance and low-temperature heat sealability. High-pressure low-density polyethylene (HP-LDPE)
) is flexible and has relatively good transparency, so it is used in all fields such as films, hollow containers, injection molded products, pipes, steel pipe covering materials, electric wire covering materials, and foam molded products. There is. However, HP-LDPE has poor impact resistance, tear resistance, environmental stress cracking resistance (ESCR), etc., and its use is limited in some areas. On the other hand, low-density polyethylene (hereinafter referred to as L-
LDPE) has better mechanical strength and ESCR than HP-LDPE, and also has good transparency, so it is expected to replace HP-LDPE in some areas. However, in recent years, there has been a demand for high-strength resin due to the increasing speed of packaging machines such as bag-making machines and filling and packaging machines, and the thinning of packaging materials, and injection molding that is flexible, has excellent impact resistance, and has a non-stick surface. Development of new products is desired. From this perspective, the present applicant previously proposed a new ethylene copolymer (Japanese Patent Laid-Open No. 53-92887), but the ethylene copolymer specifically disclosed herein has a somewhat wide compositional distribution; It was found that the blocking resistance was still insufficient because it contained low crystallinity. Also,
As a method to improve blocking resistance,
No. 57-105411 has been proposed, but the ethylene copolymer having a single melting point as in this method has a poor balance between low-temperature heat sealability and heat resistance. That is, if the melting point is lowered to impart low-temperature heat-sealability, the heat resistance will be poor, and if the melting point is raised to impart heat resistance, the heat-sealability at low temperatures will be poor. In addition, ethylene has a specific long chain branching index and a specific short chain branching distribution.
An α-olefin copolymer (Japanese Patent Laid-Open No. 126809/1983) has been proposed, but the one specifically disclosed therein has a wide composition distribution and is inferior in blocking resistance, transparency, and impact resistance. On the other hand, a method for obtaining a homogeneous copolymer using a vanadium catalyst (Japanese Patent Publication No. 1973-
No. 21212) has been proposed, but the ethylene copolymer obtained by this method also has a single melting point and, as mentioned above, has a poor balance between low-temperature heat sealability and heat resistance. Therefore, the present inventors developed an ethylene/α-olefin that has excellent impact strength and blocking resistance, environmental stress cracking resistance, transparency, and tear resistance, and has a good balance of heat resistance and low-temperature heat sealability. As a result of studying the development of polymers, it was found that the above object could be achieved by adjusting the composition distribution and molecular weight distribution to specific ranges, and the present invention was achieved. That is, the present invention provides an ethylene/α-olefin copolymer that satisfies the following (A) to (G). (A) Melt flow rate is 0.01 to 200g/
10min. (B) Density is 0.900 to 0.945 g/cm ³ . (C) The composition distribution parameter (U) expressed by the following formula (1) is 100 or less. U=100×(Cw/Cn-1)...(1) However, in the formula, Cw represents the weight average degree of branching and Cn represents the number average degree of branching. (D) Weight average molecular weight wl of low ethylene content component
and the weight average molecular weight of the high ethylene content component wh
The ratio wl/wh exceeds 1, and the molecular weight distribution of the low ethylene content component (wl/nl) and the molecular weight distribution of the high ethylene content component (wh/nh)
The ratio (wl/nl)/(wh/nh) is
0.96 or less. (E) There are multiple melting points measured by a differential scanning calorimeter (DSC), and among the multiple melting points, the highest melting point (T ₁ ) is higher than the temperature expressed by the following formula (5) and lower than 130°C . T ₁ ≧175d−43 (5) However, in the formula, d is a value expressed by the density (g/cm ³ ) of the copolymer. (F) The ratio (H ₁ /H _T ) of the heat of fusion of the crystal at the highest melting point: H ₁ and the total heat of fusion of the crystal: H _T measured by a differential scanning calorimeter (DSC) is 0.6 or less, and (G) The α-olefin copolymerized with ethylene has a carbon number ranging from 4 to 20. The ethylene/α-olefin copolymer of the present invention is defined by (A) to (G) below. (A) Melt fluororate (hereinafter abbreviated as MFR) is 0.01 to 200
g/10min, preferably 0.05 to 150g/
The range is 10min. Those with an MFR exceeding 200 g/10 min are undesirable because they have poor moldability and mechanical strength, while those with an MFR of less than 0.01 g/10 min have high melt viscosity and are poor in moldability. In the present invention
MFR is a value measured according to ASTM D 1238E. (B) a density of 0.900 to 0.945 g/cm ³ , preferably
It is in the range of 0.910 to 0.940 g/cm ³ . density is
If it is less than 0.900 g/cm ³ , it is undesirable because of poor blocking resistance, and if it exceeds 0.945 g/cm ³ , it will be poor in transparency, tear resistance, impact resistance, and low-temperature heat sealability. The density in the present invention is
This is a value measured according to ASTM D 1505. (C) The composition distribution parameter (U) expressed by the following formula (1) is 100 or less, preferably 90 or less. U=100×(Cw/Cn-1)...(1) However, in the formula, Cw represents the weight average degree of branching and Cn represents the number average degree of branching. If U exceeds 100, the composition distribution is wide and the transparency, tear resistance, impact resistance, blocking resistance, and low temperature heat sealability are poor. Cw and Cn in the present invention are values measured by the following method. That is, in order to perform compositional fractionation of the ethylene/α-olefin copolymer, the copolymer was dissolved in a mixed solvent of p-xylene and butyl cellosolve (volume ratio: 80/20), and then diatomaceous earth (trade name; Celite #560 Manufactured by John Manville (USA))
A cylindrical column was filled with the mixed solvent, and while a solvent having the same composition as the mixed solvent was transferred into the column and flowed out, the temperature inside the column was raised stepwise from 30°C to 120°C in 5°C increments. After fractionation, the coated ethylene copolymer was reprecipitated in methanol, separated, and dried to obtain a fractionated product. Next, the number of branches C per 1000 carbons of each fraction is calculated as ¹³ C−
Obtained by NMR method, the number of branches C and the cumulative weight fraction I(W) of each fractionation are based on the following lognormal distribution (Equation (2))
Assuming that Cw and
Asked for Cn. I(W)=1/β√π∫ ^C ₀ exp(-1/β ² ln ² C/Co
) d(lnC) ……(2) However, in the formula, β ² is expressed as β ² = 2ln(Cw/Cn) ……(3), and Co ² is expressed as Co ² = Cw・Cn ……(4) It is expressed as In addition, the number of branches C determined by ¹³ C-NMR method is GJRay,
PE Johnson and JRKnox, Macromolecules;
10, 773 (1977), ¹³ C−
It was determined from the area intensity using the methylene carbon signal observed in the NMR spectrum. (D) Weight average molecular weight of low ethylene content component:
Weight average molecular weight of wl and high ethylene content components:
The ratio wl/wh to Mwh exceeds 1, preferably in the range of 1.05 to 10, and the molecular weight distribution of the low ethylene content component (wl/nl) and the molecular weight distribution of the high ethylene content component (wh/nh)
The ratio (wl/nl)/(wh/nh) is
It is 0.96 or less, preferably in the range of 0.1 to 0.94. Weight average molecular weight of low ethylene content components
wl and the weight average molecular weight Mwh of the high ethylene content component are determined by dividing each fraction obtained by the above composition fractionation method into a low branching side and a high branching side with the average degree of branching of the unfractionated ethylene/α-olefin copolymer as a boundary. (If none of the branching degrees of each fraction matched the average branching degree, the fraction closest to the average branching degree was divided into two equal parts and added to the low-branching side and the high-branching side, respectively). The weight average molecular weight wl of the highly branched side, that is, the component with a low ethylene content, and the weight average molecular weight of the low branched side, that is, the component that has a high ethylene content.
It is wh. In addition, the weight average molecular weight w of each fraction obtained by composition fractionation and the unfractionated ethylene/α-olefin copolymer was determined by gel permeation chromatography (GPC).
The GPC curves of the low ethylene content component and the high ethylene content component were obtained by multiplying the GPC curve of each fraction by its weight fraction. wl/wh exceeds 1, and (wl/nl)/(wh/nh)
is 0.96 or less, it is characterized by containing a low molecular weight component with a high ethylene content, a high molecular weight component with a high ethylene content, and a high molecular weight component with a low ethylene content, but not containing a low molecular weight component with a low ethylene content. By including this component, impact strength, blocking resistance, and ESCR are particularly improved. Furthermore, the ethylene α-
The olefin copolymer was obtained by measuring the M of each fraction with a narrow composition distribution obtained by the above-mentioned composition fractionation by GPC. When specified, it has excellent impact strength, blocking resistance, ESCR, and fluidity without reducing other physical properties such as transparency.
This is preferred because it results in a copolymer with good extrusion processability. That is, in a composition-molecular weight distribution diagram expressed three-dimensionally with composition (branching degree) on the X axis, molecular weight (M) on the Y axis, and weight fraction on the Z axis, the degree of branching and unfractionated ethylene/α-olefin are The molecular weight (M) at 1/10 and 2/10 of the maximum value of the weight fraction (Z axis) corresponding to the degree of branching whose ratio to the average degree of branching of the copolymer corresponds to the value shown in Table 1. The ratio to the weight average molecular weight (wa) of unfractionated ethylene/α-olefin copolymer/wa is the common logarithm log ₁₀
The value expressed in (M/wa) is within the range shown in Table 1 on the low molecular weight side and high molecular weight side. Note that w and n were measured by GPC under the following conditions. Equipment: Model 150C manufactured by Waters Co., Ltd. Column: TSK GMH-6 (6) manufactured by Toyo Soda Kogyo Co., Ltd.
mmφ×600mm) Solvent: O-dichlorobenzene (ODCB) Temperature: 135℃ Flow rate: 1.0ml/min Injection concentration: 30mg/20ml ODCB (injection volume 400μ) Column elution volume is Toyo Soda Kogyo Co., Ltd. Calibration was performed by the universal method using standard polystyrene manufactured by Plessyer Chemical. (E) The ethylene/α-olefin copolymer of the present invention has multiple melting points measured by DSC, and among the multiple melting points, the highest melting point (T ₁ ) is the temperature expressed by the following formula (5). Above, preferably the formula
The temperature is not less than the temperature expressed by (6), and not more than 130°C, preferably not more than 125°C. If T ₁ is less than the temperature expressed by formula (5), the heat resistance will be poor, and if T ₁ exceeds 130°C, the transparency will be poor. T ₁ ≧175d−43 ...(5) T ₁ ≧175d−42.5 ...(6) However, in the formula, d is a value expressed by the density (g/cm ³ ) of the copolymer. Incidentally, the melting point and the heat of crystal fusion in term (F) in the present invention were measured by the following method. That is, a sample (approximately 3 mg) was measured using a differential scanning calorimeter.
After melting at 200°C for 5 minutes, the temperature was lowered to 20°C at a rate of 10°C/min, held at the same temperature for 1 minute, and then raised to 150°C at a rate of 10°C/min to measure an endothermic curve. Next, as shown in Figures 1 and 2, the endothermic curve is 60℃ and
130℃, and the part surrounded by the straight line (baseline) and the endothermic curve is defined as the total heat of fusion of the crystal (H _T ), and the temperature corresponding to the part that appears as a peak or shoulder on the endothermic curve is on the high temperature side. T ₁ , T ₂ . . . T _o respectively from the melting point. In addition, when T ₁ appears as a peak, the heat of crystal fusion H ₁ of T ₁ can be calculated by drawing a perpendicular line from the minimum point immediately on the low temperature side of T ₁ to the temperature coordinate axis as shown in Figure 1, and using the perpendicular line, the baseline, and the endothermic curve. If it appears as a shoulder, draw a tangent at the inflection point immediately on the low temperature side of the shoulder and the inflection point on the high temperature side of _T2 , as shown in Figure 2.
A perpendicular line is drawn from the intersection of the two tangent lines, and the high-temperature side portion (shaded portion) is surrounded by the perpendicular line, the baseline, and the endothermic curve. (F) The ratio of H ₁ to H _T (H ₁ /H _T ) measured by the DSC is 0.6 or less, preferably 0.01 or less.
It is 0.55. If H ₁ /H _T exceeds 0.6, the low temperature heat sealability and transparency will be poor. (G) The α-olefin copolymerized with ethylene has 4 to 20 carbon atoms, preferably 6 to 18 carbon atoms. Specifically, α-olefin having 4 to 20 carbon atoms includes, for example, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-tetradecene, 1 - octadecene and mixtures thereof. When propylene is used as the α-olefin, tear resistance, impact resistance, and environmental stress cracking resistance are poor. The method for producing the ethylene/α-olefin copolymer of the present invention requires three components each having a narrow compositional distribution and a narrow molecular weight distribution: a high ethylene-low molecular weight component, a high ethylene-high molecular weight component, and a low ethylene component. - A method in which high molecular weight components are polymerized separately in advance and then mechanically mixed; a method in which each component is polymerized in one polymerization reaction system and then uniformly mixed after or while being polymerized; or a combination of these methods. An example of a method is as follows. The ethylene of the present invention is prepared by mechanically mixing each component.
In order to obtain an α-olefin copolymer, sufficient care must be taken to avoid poor dispersion of each component. Examples of the melt kneader used for mixing include a Banbury mixer, a kneader, a twin screw extruder, and a single screw extruder. Further, the order in which mechanical mixing is performed is not particularly limited. Polymerization in one polymerization reaction system means producing a polymer mixture by producing each component sequentially or simultaneously in one or more reactors; When polymerizing the components, it is preferable to mix these components up to the inlet of the extruder. In addition, in the case of sequential polymerization, each component can be produced in any order, but in particular, in terms of molecular weight, the low molecular weight component is produced first, and in terms of density, the high density component (high ethylene content component) is produced first. It is preferable to avoid the formation in terms of polymerization operation, and it is suitable for industrial production. The components to be generated are not limited to the three components mentioned above, but include, for example, a component with a narrow composition distribution, high ethylene and a wide molecular weight distribution, a high molecular weight component with a narrow composition distribution and low ethylene, or a high molecular weight component with a narrow composition distribution and low ethylene. It may be two components, such as a high molecular weight component with a narrow molecular weight distribution and a low molecular weight component with a narrow composition distribution and high ethylene, and the point is that the obtained ethylene α-olefin copolymer is the first component (A) to (G). The composition and molecular weight of each component to be polymerized in advance are not particularly limited as long as the above conditions are met, but in order to sufficiently control the composition and molecular weight of the resulting ethylene/α-olefin copolymer, a production method using the above three components is recommended. is preferred. The component having a narrow composition distribution and a narrow molecular weight distribution can be produced, for example, by the following method. For example, titanium catalyst component (A) obtained by treating a highly active solid component (a) with a specific surface area of 50 m ² /g or more containing titanium, magnesium and halogen as essential components with alcohol (b), organic aluminum Using a catalyst formed from a compound catalyst component (B) and a halogen compound catalyst component (C), ethylene and α-olefin are copolymerized to a predetermined density. At this time, organoaluminum compound catalyst component (B)
When part or all of is a halogen compound, the use of the halogen compound catalyst component (C) can be omitted. The above-mentioned highly active solid component (a) can itself be a highly active titanium catalyst component and is already widely known. Basically, a magnesium compound and a titanium compound are reacted with or without an auxiliary reaction agent so as to obtain a solid component having a large specific surface area. The solid component (a) preferably has a specific surface area of about 50 to about 1000 m ² /g, more preferably about 80 to about 900 m ² /g, and its composition generally has a titanium content of about 0.2 to about 18 wt. %,
Preferably from about 0.3 to about 15% by weight, halogen/
The titanium (atomic ratio) is about 4 to about 300, preferably about 5 to about 200, and the magnesium/titanium (atomic ratio) is about 1.8 to about 200, preferably about 2 to about 120. In addition to these components, other elements,
Metals, functional groups, electron donors, etc. may optionally be included. For example, other elements or metals such as aluminum or silicon, and functional groups such as alkoxy groups or aryloxy groups may be included. One preferred method for producing the solid component is a method in which a complex of magnesium halide and alcohol is treated with an organometallic compound, and the treated product is reacted with a titanium compound. Details of this method are described in, for example, Japanese Patent Publication No. 50-32270. The alcohol used in the treatment of the highly active solid component (a) can include aliphatic, alicyclic or aromatic alcohols, and these may have substituents such as alkoxy groups. . More specifically, methanol, ethanol,
n-propanol, iso-propanol, tert-
Butanol, n-hexanol, n-oftanol, 2-ethylhexanol, n-decanol,
Examples include oil alcohol, cyclopentanol, cyclohexanol, benzyl alcohol, isopropylbenzyl alcohol, cumyl alcohol, and methoxyethanol. Among these, it is particularly preferable to use aliphatic alcohols having 1 to 18 carbon atoms. The alcohol treatment is preferably carried out in an inert hydrocarbon such as hexane or heptane, and usually the solid component (a) is suspended at a concentration of 0.005 to 0.2 mol/h, and the alcohol is added to the solid component (a). titanium 1
The contact is preferably carried out in a proportion of 1 to 80 mol, particularly 2 to 50 mol per atom. Reaction conditions vary depending on the type of alcohol, but usually -
20 to +150℃, preferably -10℃ to +100
℃ for several minutes to 10 hours, preferably
It is best to carry out the reaction for about 10 minutes to 5 hours. By alcohol treatment, alcohol is incorporated into the solid component in the form of alcohol and/or alkoxy groups, and the treatment is carried out in such a way that the amount of alcohol is 3 to 100 mol, particularly 5 to 80 mol, per titanium atom. It is preferable to do so. Due to this reaction, some titanium may be detached from the solid component,
When such a solvent-soluble component is present, after the reaction is completed, the obtained titanium catalyst component is preferably thoroughly washed with an inert solvent before being subjected to polymerization. The organoaluminum compound catalyst component (B) used together with the titanium catalyst component (A) thus obtained typically has the general formula RnAlX _3-o (R is a hydrocarbon group,
is a compound represented by halogen, o<n≦3), and specifically includes trialkylaluminum such as triethylaluminum and triisobutylaluminum, dialkylaluminum halide such as diethylaluminum chloride and diisobutylaluminum chloride, and ethylaluminum sesquis Examples include chloride, alkyl aluminum sesquihalides such as ethyl aluminum sesquibromide, alkyl aluminum dichlorides such as ethyl aluminum dichloride, and mixtures thereof. If the halogen compound catalyst component (C) described below is not used,
In the above general formula, the average composition is 1.5≦n≦
2.0, preferably 1.5≦n≦1.8 (B)
It is better to use ingredients. The halogen compound catalyst component (C) is a halogenated hydrocarbon such as ethyl chloride or isopropyl chloride, or one that can act as a halogenating agent for the component (B) such as silicon tetrachloride. When a halogenated hydrocarbon is used, it can be used in a proportion of about 2 to 5 moles per mole of component (B). When using a halogenating agent such as silicon tetrachloride, the total amount of halogen in component (B) and component (C) is 0.5 to 2 atoms, particularly 1 to 1.5 atoms per aluminum atom in component (B). It is preferable to use such proportions that it becomes atomic. The copolymerization of ethylene can be carried out in the liquid phase or in the gas phase, for example at temperatures from 0 to about 300 DEG C., in the presence or absence of an inert diluent. In particular, when copolymerization is carried out at a temperature of about 120 to 300°C, preferably about 130 to 250°C, under conditions in which the ethylene copolymer is dissolved in the coexistence of an inert hydrocarbon, the desired ethylene copolymer can be obtained. can be obtained easily. The amount of titanium catalyst component (A) used is approximately 0.0005 to approximately 1 mmol/converted to titanium atoms.
, preferably about 0.001 to about 0.1 mol/
In addition, the organoaluminum compound catalyst component (B) is in an amount that maintains polymerization activity, and the Al/Ti (atomic ratio) is approximately 1.
It is preferable to use the amount from about 2000 to about 2000, preferably from about 10 to about 500. The polymerization pressure is generally from atmospheric pressure to about 100 kg/cm ² , preferably from about 2 to about 50 kg/cm ² . The ethylene/α-olefin copolymer of the present invention is
It has excellent impact resistance and blocking resistance compared to HP-LDPE as well as conventional L-LDPE.
It has good environmental stress cracking resistance, transparency, and tear resistance, and has a good balance of heat resistance and low-temperature heat sealability, so it is particularly suitable for packaging films and injection molded products. Various molding methods such as T-die molding, inflation film molding, blow molding, injection molding, extrusion molding, powder molding, etc., including films, sheets, tapes, monofilaments, containers, daily necessities, pipes, tubes, etc. It can be processed into products. In addition, various composite films can be made by extrusion coating or coextrusion molding with other films, and steel pipe coating materials,
It is also used for applications such as wire covering materials and foam molded products. The ethylene/α-olefin copolymer of the present invention can be used with other thermoplastic resins such as HP-LDPE medium density polyethylene, high density polyethylene, polypropylene poly-1-butene, poly4-methyl-1-pentene with low crystallinity or non-crystalline properties. It can also be used in a blend with a polyolefin such as a copolymer of crystalline ethylene and propylene or 1-butene, or a propylene-1-butene copolymer. Or petroleum resin, wax, heat stabilizer, weather stabilizer,
Antistatic agents, anti-blocking agents, lubricants, nucleating agents, pigments, dyes, inorganic or organic fillers, synthetic rubber or natural rubber, etc. can also be used in combination. Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples as long as the gist thereof is not exceeded. Example 1 <Catalyst preparation> Under nitrogen atmosphere, commercially available anhydrous magnesium chloride 1
A mole was suspended in dehydrated and purified hexane 2, and 6 moles of ethanol was added dropwise over 1 hour with stirring, followed by reaction at room temperature for 1 hour. 2.6 mol of diethylaluminium chloride was added dropwise to this at room temperature,
Stirring was continued for 2 hours. Next, after adding 6 moles of titanium tetrachloride, the system was heated to 80°C and the reaction was carried out with stirring for 3 hours. The solid portion after the reaction was separated and washed repeatedly with purified hexane. The composition of the solid (A-1) was as follows. [Table] Next, Ti of A-1 suspended in purified hexane
500 mmol of ethanol was added at room temperature to 50 mmol in terms of 50 mmol, and the temperature was raised to 50°C and reacted for 1.5 hours. After the reaction, the solid portion was washed repeatedly with purified hexane. The composition of the catalyst (B-1) thus obtained was as follows. [Table] <Polymerization> Three continuous polymerization reactors with an internal volume of 200 were used, each using dehydrated hexane and Ti as solvents.
(B-1) Organic obtained above as a catalyst component
As the Al compound component, a 1:3 mixture of diethylaluminium monochloride and ethylaluminum sesquichloride was used, the polymerization temperature was 165°C, the total pressure was 30Kg/cm ² , the average residence time was 1 hour, and the concentration of the produced polymer with respect to the solvent hexane was Continuous copolymerization of ethylene and 4-methyl-1-pentene (4MP-1) was carried out under common conditions of 130 g/l. Ti catalyst component, organic Al compound component, ethylene, 4-methyl-1-pentene,
The hydrogen supply rates were varied as shown in Table 2. After the produced copolymers were discharged from each reactor, they were introduced into a mixing tank and mixed at 160° C. for an average residence time of 15 minutes. At this time,
The mixing ratio will be 1:1:1. Intrinsic viscosity “η” (dl/g), MFR (g/10min), i of the copolymer polymerized in each reactor in decalin solvent at 135°C
-Bu branching degree and density (D) (g/cm ² ) are shown in Table 3, basic physical properties of the copolymer after mixing are shown in Table 4, and relationship between branching degree and molecular weight is shown in Table 5. Next, the copolymer was molded into a 20 mmφ tubular film molding machine (manufactured by Brabender) to a width of 60 mm and a thickness of 60 mm.
It was made into a 30μ film. Molding conditions are resin temperature 180
℃, screw rotation speed 40 rpm, die diameter 26 mmφ, die slit width 0.5 mm. Next, the film was evaluated by the following method. Haze (%) ASTM D 1003 Impact strength (Kgcm/cm): Tested using a Toyo Seiki film impact tester. The spherical surface of the impact head was 1″φ. Elmendorf tear strength (Kg/cm): JISZ 1702 Blocking value (g): According to ASTM D 1893, the peeling bar was made of glass and the peeling speed was 20 cm/cm.
It was set as min. Heat sealing start temperature (°C): Using a heat sealer manufactured by Toyo Tester, heat sealing was performed at the specified temperature at a pressure of 2 Kg/cm ² and a sealing time of 1 second. The specimen width was 15 mm, and the peel test speed was 300 mm/min. The heat sealing start temperature was set as the temperature at which, during the peel test, the test piece began to break not due to peeling of the sealing surface but to the original fabric portion. In addition, the copolymer may be press-molded.
A test piece of 200 mm x 200 mm x 2 mm was prepared, and the following physical properties were measured. ESCR (hours): ASTM D 1693 Vicat Softening Point (°C): ASTM D 1525 The results are shown in Table 6. Example 2 In Example 1, each catalyst component, 4-methyl-
Continuous copolymerization and mixing operations were carried out in the same manner as in Example 1, except that the supply rates of 1-pentene and hydrogen were changed as shown in Table 2. The results for the copolymers obtained in each reactor are shown in Table 3, and the results for the copolymers after mixing are shown in Tables 4 to 6, respectively. Example 3 Two polymerization reactors similar to those in Example 1 were used, and in reactor R-1, the same catalyst components as in each reactor in Example 1 were used, and the polymer concentration was set to 65
In reactor R-2, the polymer concentration was determined using (A-1) obtained in Example 1 as the Ti catalyst component and diethyaluminum monochloride as the organic Al compound component. Continuous polymerization was carried out at the same feed rate of 130 g as in Example 1 and the feed rate of each component shown in Table 2. As in Example 1, the mixing operation was performed in a mixing tank. The mixing ratio at this time is 1:2. The results are shown in Tables 3 to 6. Comparative Example 1 In Example 3, the catalyst component in reactor R-2, 4-methyl-1- in R-1 and R-2
Polymerization and mixing were carried out in the same manner as in Example 3, except that the supply rates of pentene and hydrogen were changed as shown in Table 2. The results are shown in Tables 3 to 6. The polymer obtained here had a low ethylene content and a small amount of high molecular weight components, so it was inferior in impact strength and blocking resistance. Comparative Examples 2 and 3 Using only one polymerization reactor, using (A-1) obtained in Example 1 as the Ti catalyst component and triethylaluminum as the organic Al compound component, continuous polymerization was carried out under the conditions shown in Table 2. , the mixing was carried out. The results are shown in Tables 3 to 6. The polymer obtained here has a fairly wide compositional distribution and contains many highly crystalline and low crystalline substances.
It was inferior in transparency, blocking resistance, and low-temperature heat sealability. Comparative Example 4 Using two polymerization reactors similar to those in Example 1, using (A-1) as the Ti catalyst component and triethylaluminum as the organic Al compound component, at a polymer concentration of 130 g/2, the reactions shown in Table 2 were carried out. Continuous polymerization and mixing were performed under the conditions shown. At this time, the mixing ratio of the produced copolymers is 1:1. The results are shown in Tables 3 to 6. The polymer obtained here has a fairly wide composition distribution,
Since it contains both highly crystalline and low-crystalline substances, its transparency, blocking resistance, and low-temperature heat sealability are still insufficient. [Table] [Table] [Table] [Table] [Table] [Table] [Table] [Table] [Table] [Table] [Table] [Table] [Table] [Table] [Table]

[Brief explanation of drawings]

Figures 1 and 2 are DSC of ethylene copolymer.
The endothermic curve is shown.

Claims (1)

[Claims] 1 (A) Melt flow rate is 0.01 to 200
g/10min. (B) Density is 0.900 to 0.945 g/cm ³ . (C) The composition distribution parameter (U) expressed by the following formula (1) is 100 or less. U=100×(Cw/Cn−1) (1) However, in the formula, Cw represents the weight average degree of branching and Cn represents the number average degree of branching. (D) Weight average molecular weight wl of low ethylene content component
and the weight average molecular weight of the high ethylene content component wh
The ratio wl/wh exceeds 1, and the molecular weight distribution of the low ethylene content component (wl/nl) and the molecular weight distribution of the high ethylene content component (wh/nh)
The ratio (wl/nl)/(wh/nh) is
0.96 or less. (E) There are multiple melting points measured by a differential scanning calorimeter (DSC), and among the multiple melting points, the highest melting point (T ₁ ) is equal to or higher than the temperature expressed by the following formula (5) and is 130°C below. T ₁ ≧175d−43 (5) However, in the formula, d is a value expressed by the density (g/cm ³ ) of the copolymer. (F) The heat of fusion of the crystal at the highest melting point measured by a differential scanning calorimeter (DSC): The ratio of H ₁ to the total heat of fusion of the crystal (H _T ) H ₁ /H _T is 0.60 or less, and (G) Ethylene and The α-olefin to be copolymerized has 4 to 20 carbon atoms. An ethylene/α-olefin copolymer characterized by: