JP2014083770A - Ethylene based polymer and resin composition for foam blow molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ethylene based polymer and a resin composition for foam blow molding, having excellent stiffness and heat resistance, exhibiting higher expansion ratio in comparison with a conventionally known ethylene based polymer for foam blow molding, capable of weight saving, and having excellent thermal insulation performance, less deviation in thickness, and specific physical properties.SOLUTION: An ethylene based polymer for foam blow molding manufactured using a metallocene catalyst satisfies the following physical properties (a) to (d): (a) melt flow rate (MFR): 0.05 g/10 min or more and less than 1.0 g/10 min at a temperature of 190°C for a load of 2.16 kg; (b) density: 935 kg/mor more; (c) ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw/Mn): 3.0 to 5.9; and (d) melt tension: 4.0 to 11.4 cN.

Description

  The present invention relates to an ethylene polymer for foam blow molding. More specifically, the present invention is excellent in rigidity and heat resistance, and has a high foaming ratio and is lighter than conventionally known ethylene polymers for foam blow molding. The present invention relates to an ethylene-based polymer for foam blow molding and a resin composition having specific physical properties that can be made, have excellent heat insulation properties, and have little uneven thickness.

  In recent years, plastic pipes, films and blow molded articles have been actively used in various industrial fields. In particular, blow molded bodies made of ethylene polymers are used in various applications because they are inexpensive and lightweight, and are excellent in moldability, chemical resistance, recyclability, and the like. Attempts to improve the processing characteristics in these various blow moldings are performed because the molding process is carried out with the ethylene polymer in a molten state, and various processes such as melt flowability (easy extrudability), melt stretchability, melt tension, etc. Research has been conducted with an emphasis on improving the melting characteristics of these.

  Also, from the viewpoints of weight reduction, heat insulation, etc., an ethylene polymer and a foaming agent are melt-kneaded with an extruder, and a foamed molten resin film (parison) is extruded from a die and molded by sandwiching with a mold. Foam blow molded articles have been studied. Also in such a foam blow molded article, in order to obtain a foam having a high expansion ratio, the above-described melting characteristics, particularly the melt tension is important.

  As an ethylene polymer having a high melt tension, a low density ethylene polymer (LDPE) produced by a high-pressure radical method and having a long chain branch is known. Although LDPE is excellent in foamability, since the density range which can be manufactured is limited, when it is made into a blow-molded foam, rigidity and heat resistance are insufficient, and its application is limited.

  On the other hand, among ethylene polymers obtained with Ziegler catalysts or metallocene catalysts, high-density ethylene polymers are known. A molded product could not be obtained.

  Further, an ethylene polymer produced using a Cr-based catalyst (Phillips catalyst) is known as an ethylene-based polymer having a high density and a high melt tension. However, the ethylene-based polymer produced using a Cr-based catalyst has insufficient melt stretchability, and a good foamed molded product could not be obtained.

  Thus, it has been difficult to obtain a foamed blow molded article having high rigidity, heat resistance and a high expansion ratio using an ethylene-based polymer.

  Therefore, a method of blending LDPE with a high-density ethylene polymer has been proposed (see Patent Document 1). However, in order to increase the expansion ratio, it is necessary to increase the ratio of LDPE, and as a result, a decrease in rigidity and heat resistance cannot be avoided. Moreover, since the blow moldability is not sufficient, it is easily affected by molding conditions, and uneven thickness tends to cause thinning and opening at the corner.

  Although a method of adding a thickener has also been proposed (see Patent Document 2), there is a problem in cost because an expensive thickener is used.

  In addition, an uncrosslinked ethylene polymer foamed molded article excellent in foaming performance comprising an ethylene polymer having specific properties has been proposed (see Patent Document 3).

  Furthermore, a polyethylene-based resin foam blow molded article having a high expansion ratio containing a high-density polyethylene-based resin and a method for producing the same have been proposed (see Patent Document 4).

  However, although these ethylene-based polymers are excellent in foaming properties, when used in foam blow molding, further improvement in physical properties in foam blow molded products such as low rigidity, low-temperature impact properties and low unevenness is desired. It was rare.

JP 2006-305793 A Japanese Patent Laid-Open No. 2007-160582 Japanese Patent Laid-Open No. 2006-96910 JP 2010-260229 A

  In view of the above-mentioned problems of the prior art, the object of the present invention is excellent in rigidity and heat resistance, and has a high foaming ratio, a light weight, and a heat insulating property as compared with a conventionally known ethylene polymer for foam blow molding. Another object of the present invention is to provide an ethylene-based polymer for foam blow molding and a resin composition having excellent properties and low unevenness.

  As a result of intensive studies in order to solve the above problems, the present inventors have obtained these problems by using an ethylene polymer and a resin composition having a specific MFR, density, molecular weight distribution, and melt tension. The present inventors have found that a foamed blow molded article that solves the above problems can be produced, and have completed the present invention.

That is, according to the present invention, an ethylene-based heavy for foam blow molding, which is used for the production of a foam blow molded article, is produced by a metallocene catalyst, and satisfies the following physical properties (a) to (d): Coalescence (A) is provided.
[Ethylene polymer (A)]
Physical property (a): Melt flow rate (MFR) at a temperature of 190 ° C. and a load of 2.16 kg is 0.05 g / 10 min or more and less than 1.0 g / 10 min. Physical property (b): Density is 935 kg / m ³ or more. Certain physical property (c): Ratio (Mw / Mn) of weight average molecular weight (Mw) and number average molecular weight (Mn) determined by gel permeation chromatography (GPC) is 6.0 to 15 Physical property (d) The melt tension is 11.5 to 40 cN. According to the second invention of the present invention, the ethylene polymer (A) 10 to 99% by weight and the following physical properties (e) to (h) 1 to 90% by weight of an ethylene-based polymer (B) for foam blow molding produced by a Ziegler catalyst characterized by being satisfied (total of (A) and (B) is 100% by weight) Foam blow molding Resin composition is provided.
[Ethylene polymer (B)]
Physical property (e): Melt flow rate (MFR) at a temperature of 190 ° C. and a load of 2.16 kg is 0.01 to 1.0 g / 10 minutes Physical property (f): Density is 935 kg / m ³ or more Physical property (g ): Ratio (Mw / Mn) of weight average molecular weight (Mw) and number average molecular weight (Mn) determined by gel permeation chromatograph (GPC) is 6.0 to 30 Physical property (h): Melt tension is 2.0 to 40 cN

  According to the present invention, since it is an ethylene polymer for foam blow molding having a specific MFR, density, molecular weight distribution, and melt tension, and a resin composition, a blowing agent is added to the blown blow at the time of blow molding. By carrying out at a specific pressure and time, a uniform and high density foamed blow molded product can be obtained.

  The molded foam-molded container is a container that has higher rigidity and resistance to deformation than an unfoamed container of the same weight, and the molded container also has performance such as heat insulation.

  In foam blow molding, compared to foaming in injection molding or extrusion sheet molding, the foaming parison extruded from the die core is crushed by the mold in the process of blowing with a blow pin, and the air bubbles inside the parison are exposed to the outside. Previously, it was difficult to obtain a fine and high-density foam product due to escape, but the present invention makes it easy to perform foam molding, and the molded product is superior in terms of quality and cost. Therefore, the industrial utility is very high.

  The ethylene polymer (A) and the resin composition used for the foamed blow body of the present invention will be described.

  The ethylene polymer (A) belongs to a category generally referred to as an ethylene polymer, and in particular, an ethylene homopolymer composed of a repeating unit derived from ethylene, or a repeating unit derived from ethylene and a carbon number of 3 An ethylene-α-olefin copolymer consisting of repeating units derived from α-8 olefins is preferred.

  The ethylene polymer (A) of the present invention has an MFR measured in accordance with JIS K6922-2 of 0.05 g / 10 min or more and less than 1.0 g / 10 min at a temperature of 190 ° C. and a load of 2.16 kg. When the MFR is less than 0.05 g / 10 minutes, the resin pressure increases during molding and the resin temperature tends to increase. There is also a problem that the skin surface of the molded product is not smooth. In addition, when the MFR is 1.0 g / 10 min or more, the uneven thickness increases because the drawdown is large and the thickness of the upper and lower parts of the product is different. The MFR can be adjusted by the polymerization temperature, the use of a chain transfer agent, or the like.

The ethylene polymer (A) of the present invention has a density of 935 kg / m ³ or more measured according to JIS K7676. When the density is less than 935 kg / m ³ , the molded body has low rigidity, and it is difficult to maintain the strength of the thin product. Further, the obtained foamed blow body is inferior in heat resistance, and the foam is deformed in an environment of around 100 ° C., which causes a problem in use. Density. The amount of α-olefin copolymerized with ethylene can be adjusted.

  The ethylene polymer (A) of the present invention has a weight average molecular weight (Mw) to number average molecular weight (Mn) ratio (Mw / Mn) of 6.0 to 15. When Mw / Mn is less than 6.0, the surface of the molded body tends to be rough. Moreover, when Mw / Mn exceeds 15, a molding temperature range becomes narrow.

  The ethylene polymer (A) of the present invention has a melt tension (MT) of 11.5 to 40 cN. For melt tension (MT), Capillograph 1-B manufactured by Toyo Seiki Seisakusho Co., Ltd., with a capillary diameter of 2 mm and a capillary length of 8 mm, the molten resin extruded at 190 ° C. and a piston speed of 10 mm / min is taken up by 4 m / min. It is determined by measuring the melt tension when it is drawn to the filament at a speed. When the melt tension is less than 11.5 cN, the foaming property tends to decrease, and when it exceeds 40 cN, uniform stretching becomes difficult, and the resin pressure and the resin temperature tend to increase.

  The foam blow molding resin composition of the present invention is produced by a Ziegler catalyst characterized by satisfying 10 to 99% by weight of the ethylene polymer (A) and the physical properties (e) to (h). 1 to 90% by weight of the ethylene polymer (B) (the total of (A) and (B) is 100% by weight).

  The ethylene polymer (B) has an MFR of 0.01 g / 10 min or more and less than 1.0 g / 10 min at a temperature of 190 ° C. and a load of 2.16 kg. When the MFR is less than 0.01 g / 10 min, the resin pressure increases during molding and the resin temperature tends to increase. There is also a problem that the skin surface of the molded product is not smooth. In addition, when the MFR is 1.0 g / 10 min or more, the uneven thickness increases because the drawdown is large and the thickness of the upper and lower parts of the product is different.

The density of the ethylene polymer (B) is 935 kg / m ³ or more. When the density is less than 935 kg / m ³ , the molded body has low rigidity and it is difficult to maintain the strength of the thin product. Further, the obtained foamed blow body is inferior in heat resistance, and the foam is deformed in an environment of around 100 ° C., which causes a problem in use.

  In the ethylene polymer (B), the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 6.0 to 30. If Mw / Mn is less than 6.0, the surface of the molded body tends to be rough. When Mw / Mn exceeds 30, the pinch-off strength and the weld strength tend to decrease.

  The ethylene polymer (B) has a melt tension (MT) of 2.0 to 40 cN. When the melt tension is less than 2.0 cN, the drawdown property tends to be lowered, and when it exceeds 40 cN, uniform stretching becomes difficult, and the resin pressure and the resin temperature tend to increase.

  The composition of the foam blow molding resin composition of the present invention is 10 to 99% by weight of the ethylene polymer (A) and 1 to 90% by weight of the ethylene polymer (B) ((A) and (B ) Is 100% by weight). Foaming performance is largely attributed to the ethylene polymer (A), and when the ethylene polymer (A) is less than 10% by weight, the foamability tends to decrease.

  As described above, by using an ethylene polymer and a resin composition having a specific MFR, density, molecular weight distribution, and melt tension in the present invention, it is excellent in rigidity and heat resistance, and conventionally known ethylene for foam blow molding Compared with a system polymer and a resin composition, it is possible to produce a foamed blow molded article having a high foaming ratio, being able to be reduced in weight, excellent in heat insulation, and having less uneven thickness.

  Next, the manufacturing method of the ethylene-type polymer for foam blow molding of this invention and a resin composition is demonstrated.

  The ethylene polymer (A) of the present invention is produced using a metallocene catalyst. The metallocene catalyst to be used has a metallocene complex, an activation cocatalyst, and, if necessary, an organoaluminum compound as constituents. At the same time as the synthesis of the macromonomer, the macromonomer, ethylene and an olefin having 3 to 6 carbon atoms are copolymerized. It is preferable to carry out.

  The macromonomer is an olefin polymer having a vinyl group at the terminal, and is an ethylene polymer having a vinyl group at the terminal obtained by homopolymerizing ethylene or copolymerizing ethylene and an olefin having 3 to 6 carbon atoms. . As metallocene catalysts for synthesizing macromonomers and copolymerizing macromonomers, ethylene and olefins having 3 to 6 carbon atoms, metallocene complexes include non-crosslinked bis (indenyl) zirconium complexes and non-crosslinked bis (cyclopentadiene). Enyl) zirconium complex, bridged bis (cyclopentadienyl) zirconium complex, bridged bis (indenyl) zirconium complex, bridged (cyclopentadienyl) (indenyl) zirconium complex, bridged (cyclopentadienyl) (fluorenyl) ) A catalyst using a zirconium complex or a crosslinked (indenyl) (fluorenyl) zirconium complex is preferred. Specific examples of metallocene complexes include, for example, bis (indenyl) zirconium dichloride, dimethylsilanediylbis (cyclopentadienyl) zirconium dichloride, dimethylsilanediyl (cyclopentadienyl) (indenyl) zirconium dichloride, dimethylsilanediyl (cyclopenta). Dienyl) (2-methylindenyl) zirconium dichloride, dimethylsilanediyl (cyclopentadienyl) (4,7-dimethylindenyl) zirconium dichloride, dimethylsilanediyl (cyclopentadienyl) (2,4,7- Trimethylindenyl) zirconium dichloride, diphenylmethylene (1-cyclopentadienyl) (9-fluorenyl) zirconium dichloride, diphenylmethylene (1-cyclopenta Dichlorides such as enyl) (2,7-di-t-butyl-9-fluorenyl) zirconium dichloride, isopropylidene (1-cyclopentadienyl) (2,7-di-t-butyl-9-fluorenyl) zirconium dichloride Examples of the transition metal compound include dimethyl, diethyl, dihydro, diphenyl, and dibenzyl. Moreover, although the compound which substituted the zirconium atom of the said transition metal compound with the titanium atom or the hafnium atom can also be illustrated, it is not limited to these. Among these, you may use 1 type or multiple types.

  The activation cocatalyst used as a component of the metallocene catalyst is a compound that plays a role in converting a metallocene complex or a reaction product of a metallocene complex and an organoaluminum compound into an active species capable of olefin polymerization. It is preferable that it is a compound which produces | generates a reactive compound, and the produced | generated cationic compound acts as a polymerization active seed | species which can superpose | polymerize an olefin. An activation co-catalyst is a compound that provides a compound that, after forming a polymerization active species, coordinates weakly or interacts with the generated cationic compound, but does not react directly with the active species.

  Specific examples of the activation promoter include alkylaluminoxanes such as methylaluminoxane, silica gel-supported alkylaluminoxanes, tris (fluorinated aryl) borons such as tris (pentafluoreophenyl) boron, N, N-dimethylammonium-tetrakis ( Examples thereof include boron compounds such as tetrakis (fluorinated aryl) boron salts such as pentafluorophenyl) boron, silica gel-supported materials thereof, clay minerals, clay minerals treated with organic compounds, and the like. Among them, it is preferable to use a clay mineral treated with an organic compound.

  When a clay mineral treated with an organic compound is used as the activation promoter, the clay mineral used is preferably a clay mineral belonging to the smectite group, and specific examples include montmorillonite, beidellite, saponite, hectorite and the like. It is also possible to use a mixture of a plurality of these clay minerals.

  The organic compound treatment means introducing an organic ion between clay mineral layers to form an ionic complex. Examples of the organic compound used in the organic compound treatment include N, N-dimethyl-n-octadecylamine hydrochloride, N, N-dimethyl-n-eicosylamine hydrochloride, N, N-dimethyl-n-docosylamine hydrochloride, N, N-dimethyloleylamine hydrochloride, N, N-dimethylbehenylamine hydrochloride, N-methyl-bis (n-octadecyl) amine hydrochloride, N-methyl-bis (n-eicosyl) amine hydrochloride, N-methyl -Alkylammonium salts such as dioleylamine hydrochloride, N-methyl-dibehenylamine hydrochloride, N, N-dimethylaniline hydrochloride can be exemplified.

  The metallocene catalyst is not particularly limited in the method for preparing the metallocene catalyst such as a method in which a metallocene complex is reacted with an activation promoter.

  As the metallocene catalyst, an alkylaluminum such as triethylaluminum or triisobutylaluminum may be used as necessary for the activation of the metallocene complex and the removal of impurities in the solvent during the preparation of the catalyst.

  When producing the ethylene-based polymer (A) of the present invention, it is preferably carried out at a polymerization temperature of −100 to 120 ° C., particularly considering productivity, preferably 20 to 120 ° C., more preferably 60 to 120 ° C. It is preferable to carry out within a range. The polymerization time is preferably in the range of 10 seconds to 20 hours, and the polymerization pressure is preferably in the range of normal pressure to 300 MPa. The polymerizable monomer is ethylene and an α-olefin having 3 to 6 carbon atoms, and the supply ratio of ethylene and the α-olefin having 3 to 6 carbon atoms is ethylene / α-olefin having 3 to 6 carbon atoms ( A feed ratio of 1 to 200, preferably 3 to 100, and more preferably 5 to 50 can be used. It is also possible to adjust the molecular weight using hydrogen during polymerization. The polymerization can be carried out by any of batch, semi-continuous and continuous methods, and can be carried out in two or more stages by changing the polymerization conditions. In addition, the ethylene copolymer can be obtained by separating and recovering from the polymerization solvent by a conventionally known method after the completion of the polymerization and drying.

  Polymerization can be carried out in a slurry state, a solution state, or a gas phase state. In particular, when the polymerization is performed in a slurry state, an ethylene-based copolymer having a powder particle shape is efficiently and stably produced. Can do.

  The ethylene-based polymer (B) of the present invention was high-density polyethylene (HDPE) produced using a Ziegler catalyst, and a commercially available product was used.

  Next, the manufacturing method of the foam blow molded object using the ethylene-type polymer for foam blow molding of this invention and a resin composition is demonstrated.

  The foamed blow molded article of the present invention is obtained by melt-kneading the ethylene polymer of the present invention and the resin composition and a foaming agent with an extruder, extruding a foamed molten resin film (parison) from a die, and sandwiching it with a mold. Can be manufactured. As a molding machine at that time, a known blow molding machine such as an accumulator type and a direct mold, a foam blow molding machine having a device capable of injecting a foaming agent in the middle of an extruder, or the like can be used.

  Examples of the foaming agent include inorganic gas foaming agents such as carbon dioxide, nitrogen, argon, and air; and volatile foaming agents such as propane, butane, pentane, hexane, cyclobutane, cyclohexane, trichlorofluoromethane, and dichlorodifluoromethane. be able to. Also, azodicarbonamide, barium azodicarboxylate, N, N-dinitrosopentamethylenetetramine, 4,4′-oxybis (benzenesulfonylhydrazide), diphenylsulfone that is liquid or solid at room temperature and generates gas upon heating. Examples thereof include chemical blowing agents such as -3,3'-disulfonylhydrazide, p-toluenesulfonyl semicarbazide, trihydrazinotriazine, biurea, zinc carbonate, and sodium bicarbonate (sodium bicarbonate). A plurality of foaming agents can be used in combination. The addition amount of the foaming agent is preferably 0.1 to 20 parts by weight, particularly 2 to 8 parts by weight with respect to 100 parts by weight of the ethylene polymer and resin composition of the present invention. preferable.

  Any method may be used as a method of mixing the foaming agent with the ethylene polymer and the resin composition as long as the foamed blow molded article is obtained. For example, the ethylene polymer, the resin composition, and the foaming agent may be mixed in advance. A method in which a composition mixed with a mixer represented by a Henschel mixer, a V-blender, a ribbon blender, a tumbler blender, etc. is put into a blow molding machine and foamed, an ethylene polymer, a resin composition, and a foaming agent. A method of separately introducing an extruder and melt-mixing in the extruder can be exemplified.

  The expansion ratio of the foamed blow molded article of the present invention thus produced is 1.5 to 30 times, more preferably 2 to 30 times.

  The ethylene polymer and the resin composition constituting the foamed blow molded article of the present invention may be blended with other optional compounding components according to various purposes without departing from the purpose of the present invention, These additional blending components may be those used as usual polyolefin additives and blending materials, such as crystallization nucleating agents, antioxidants, neutralizing agents, weather resistance improvers, dispersants, antistatic agents. Agents, lubricants, molecular weight modifiers (peroxides, etc.), heat stabilizers, light stabilizers, UV absorbers, lubricants, antifogging agents, antiblocking agents, slip agents, flame retardants, conductivity-imparting agents, crosslinking agents , Crosslinking aids, metal deactivators, antibacterial agents, fluorescent brighteners and other auxiliary agents, other various resins and elastomers, fillers, colorants and the like.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Below, the measuring method used by the Example and the comparative example is shown.
[Production method and evaluation method of ethylene polymer]
Examples of production will be specifically described below, but the present invention is not limited thereto. Unless otherwise noted, the reagents used were commercially available products or those synthesized according to known methods.

  A jet mill (trade name: CO-JET SYSTEM α MARK III, manufactured by Seishin Enterprise Co., Ltd.) was used for pulverization of the organically modified clay, and the particle size after pulverization was measured using a microtrack particle size distribution analyzer (trade name, manufactured by Nikkiso Co., Ltd.). MT3000) was used to measure ethanol as a dispersant.

  Preparation of the ethylene polymer production catalyst, production of the ethylene polymer and solvent purification were all carried out under an inert gas atmosphere. A hexane solution (20 wt%) of triisobutylaluminum manufactured by Tosoh Finechem Co., Ltd. was used.

  Furthermore, various physical properties of the ethylene-based polymer in the examples were measured by the following methods.

  The MFR (melt flow rate) was measured at a temperature of 190 ° C. and a load of 2.16 Kg according to JIS K6922-2.

  The density was measured by a density gradient tube method in accordance with JIS K7676.

The weight average molecular weight (Mw), the number average molecular weight (Mn) and the ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn) were measured by GPC. The column temperature was set to 140 ° C. using a GPC device (trade name: HLC-8121 GPC / HT, manufactured by Tosoh Corporation) and a column (trade name: TSKgel GMHhr-H (20) HT, manufactured by Tosoh Corporation). The measurement was performed using 1,2,4-trichlorobenzene as an eluent. A measurement sample was prepared at a concentration of 1.0 mg / ml, and 0.3 ml was injected and measured. The calibration curve of molecular weight was calibrated using a polystyrene sample having a known molecular weight. In addition, Mw and Mn were obtained as linear ethylene polymer equivalent values. The sample for measuring the melt tension was a heat-resistant stabilizer (manufactured by Ciba Specialty Chemicals, Irganox 1010TM; 1,500 ppm, Irgaphos 168TM; 1,500 ppm) was added and kneaded for 30 minutes at 190 ° C. and 30 rpm in a nitrogen stream using an internal mixer (trade name Lab Plast Mill, manufactured by Toyo Seiki Seisakusho).

To measure the melt tension, a capillary viscometer (Toyo Seiki Seisakusho, trade name Capillograph) with a barrel diameter of 9.55 mm is attached with a die with a length of 8 mm and a diameter of 2.095 mm so that the inflow angle is 90 °. It was measured. The temperature was set to 190 ° C., the piston lowering speed was set to 10 mm / min, the stretch ratio was set to 47, and the load (cN) required for take-up was taken as the melt tension. When the maximum draw ratio was less than 47, the load (cN) necessary for taking-up at the highest draw ratio that did not break was taken as the melt tension.
[Molding of blow-molded foam]
Using a single-layer blow molding machine (made by Plako Co., Ltd.) having a 65 mmφ extrusion screw, a 0.2 μm filter was attached to the blowing air port, a cylinder temperature of 220 ° C., a thickness of 1.5 mm, and a container volume of 1000 ml. A container was formed.
[Evaluation of foamed blow molded products]
The foaming ratio was measured by measuring the apparent specific gravity of the foamed blow molded article with a hydrometer (trade name: DME-220H, manufactured by Shinko Denshi Co., Ltd.), and obtaining the foaming ratio from the ratio with the density of the ethylene polymer. .

  Also, when evaluating the drawdown resistance and thickness homogeneity of the parison during foam blow molding, it was determined that ◯ was good, X was a poor molding, and △ was a slight molding defect. did.

Production Example 1
[Production of ethylene polymer (A-1)]
(1) Denaturation of clay In 6 liters of distilled water, 150 g of concentrated hydrochloric acid, 642 g (1.2 mol) of methyldioleilamine (Lion Corporation (trade name) Armin M2O) and synthetic hectorite (trade name, manufactured by Rockwood Additives) (trade name) After adding 1 kg of Laponite RD), the mixture was heated to 60 ° C. and stirred for 1 hour while maintaining the temperature. This slurry was filtered, washed twice with 6 liters of distilled water at 60 ° C., and dried in an oven at 85 ° C. for 12 hours to obtain 1.4 kg of organically modified clay. This organically modified clay was crushed by a jet mill to have a median diameter of 15 μm.
(2) Preparation of catalyst suspension After substituting a 5-liter flask equipped with a thermometer and a reflux tube with nitrogen, 500 g of the modified clay obtained in (1) and 3.1 liters of hexane were added, and then dimethylsilanediyl Bis (cyclopentadienyl) zirconium dichloride 6.41 g, diphenylmethylene (cyclopentadienyl) (2,7-di-tert-butyl-9-fluorenyl) zirconium dichloride 1.07 g and 20% triisobutylaluminum 1.4 1 liter was added and it stirred at 60 degreeC for 3 hours. After cooling to 45 ° C., the supernatant was extracted, washed 5 times with 4 liters of hexane, and then added with 4 liters of hexane to obtain a catalyst suspension (solid weight: 11.0 wt%).
(3) Production of ethylene polymer (A-1) In a polymerizer having an internal volume of 540 L, hexane was 145 kg / hour, ethylene was 32 kg / hour, butene-1 was 0.7 kg / hour, hydrogen was 7 NL / hour, and The catalyst suspension prepared in (2) above is continuously supplied so that the polymer production amount becomes 30 kg / hour, and the polymerization reaction is continuously carried out while maintaining the total pressure at 3,000 kPa and the polymerization vessel internal temperature at 85 ° C. Went.

After continuously removing the slurry from the polymerization vessel and removing unreacted hydrogen, ethylene, and butene-1, ethylene polymer (A-1) powder was obtained through the steps of separation and drying. This was melt-kneaded using a 50 mm diameter single-screw extruder set at 200 ° C. and pelletized to obtain ethylene polymer (A-1) pellets. The density of the obtained ethylene polymer (A-1) pellets is 950 kg / m ³ , MFR is 0.9 g / 10 min, and the ratio Mw / Mn of weight average molecular weight (Mw) to number average molecular weight (Mn) is 8 .6, the melt tension was 20 cN.

Production Example 2
[Production of ethylene polymer (A-2)]
(1) Modification of clay (2) Preparation of catalyst suspension The same procedure as in Production Example 1 was performed.
(3) Production of ethylene polymer (A-2) In a polymerization vessel having an internal volume of 540 L, hexane was 145 kg / hour, ethylene was 32 kg / hour, butene-1 was 1.6 kg / hour, hydrogen was 7 NL / hour, and The catalyst suspension prepared in (2) above is continuously supplied so that the polymer production amount is 30 kg / hour, and the polymerization reaction is continuously performed while maintaining the total pressure at 3,000 kPa and the polymerization vessel internal temperature at 75 ° C. Went.

After continuously removing the slurry from the polymerization vessel and removing unreacted hydrogen, ethylene, and butene-1, ethylene polymer (A-2) powder was obtained through separation and drying steps. This was melt-kneaded using a 50 mm diameter single-screw extruder set at 200 ° C. and pelletized to obtain ethylene polymer (A-2) pellets. The density of the obtained ethylene polymer (A-2) pellets is 940 kg / m ³ , MFR is 0.9 g / 10 min, and the ratio Mw / Mn of weight average molecular weight (Mw) to number average molecular weight (Mn) is 9 The melt tension was 21 cN.

Production Example 3
[Production of ethylene polymer (A-3)]
(1) Modification of clay (2) Preparation of catalyst suspension The same procedure as in Production Example 1 was performed.
(3) Production of ethylene polymer (A-3) In a polymerizer having an internal volume of 540 L, hexane was 145 kg / hour, ethylene was 32 kg / hour, butene-1 was 1.2 kg / hour, hydrogen was 5 NL / hour, and The catalyst suspension prepared in (2) above is continuously supplied so that the polymer production amount is 30 kg / hour, and the polymerization reaction is continuously carried out while maintaining the total pressure at 3,000 kPa and the polymerization vessel internal temperature at 80 ° C. Went.

After continuously removing the slurry from the polymerization vessel and removing unreacted hydrogen, ethylene, and butene-1, ethylene polymer (A-3) powder was obtained through steps of separation and drying. This was melt-kneaded using a 50 mm diameter single screw extruder set at 200 ° C. and pelletized to obtain ethylene polymer (A-3) pellets. The density of the obtained ethylene polymer (A-3) pellets is 945 kg / m ³ , the MFR is 0.8 g / 10 min, and the ratio Mw / Mn of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 8 .8, the melt tension was 30 cN.

Production Example 4
[Production of ethylene polymer (C-1)]
(1) Modification of clay (2) Preparation of catalyst suspension The same procedure as in Production Example 1 was performed.
(3) Production of ethylene polymer (C-1) In a polymerization vessel having an internal volume of 540 L, hexane was 145 kg / hour, ethylene was 32 kg / hour, butene-1 was 0.7 kg / hour, hydrogen was 25 NL / hour, and The catalyst suspension prepared in (2) above is continuously supplied so that the polymer production amount becomes 30 kg / hour, and the polymerization reaction is continuously carried out while maintaining the total pressure at 3,000 kPa and the polymerization vessel internal temperature at 85 ° C. Went.

The slurry was continuously extracted from the polymerization vessel to remove unreacted hydrogen, ethylene, and butene-1, and then an ethylene polymer (C-1) powder was obtained through separation and drying processes. This was melt-kneaded using a 50 mm diameter single screw extruder set at 200 ° C. and pelletized to obtain ethylene polymer (C-1) pellets. The density of the obtained ethylene polymer (C-1) pellets is 952 kg / m ³ , MFR is 3.7 g / 10 min, and the ratio Mw / Mn of weight average molecular weight (Mw) to number average molecular weight (Mn) is 8 .8, the melt tension was 13 cN.

Example 1
[Molding of blow-molded foam]
100 parts by weight of the ethylene polymer (A-1) produced in Production Example 1 and 3 parts by weight of a baking soda-based foaming agent masterbatch (product name: EE-275F) are dry blended, and a single layer blow molding machine ( A cylindrical foaming container having a cylinder temperature of 220 ° C., a thickness of 1.5 mm, and a container volume of 1000 ml was molded using Plako Co., Ltd.

  And the drawdown resistance of the parison at the time of foam blow molding, the measurement of the foaming ratio of a foam container, and the evaluation of thickness uniformity were performed. These results are shown in Table 1.

Example 2
The same procedure as in Example 1 was conducted except that the ethylene polymer (A-1) was changed to the ethylene polymer (A-2). The evaluation results of foaming blow are shown in Table 1.

Example 3
The same procedure as in Example 1 was conducted except that the ethylene polymer (A-1) was changed to the ethylene polymer (A-3). The evaluation results of foaming blow are shown in Table 1.

Example 4
Ethylene polymer (A-1), ethylene polymer (A-1) 90 parts by weight and ethylene polymer (B-1) (manufactured by Tosoh Corporation, trade name: Nipolon Hard, grade: 8600A) 10 weights The procedure was the same as in Example 1 except that the change was made to the part. The evaluation results of foaming blow are shown in Table 1.

Example 5
Ethylene polymer (A-1), 10 parts by weight of ethylene polymer (A-2) and ethylene polymer (B-1) (manufactured by Tosoh Corporation, trade name: Nipolon Hard, grade: 8600A) The procedure was the same as in Example 1 except that the change was made to the part. The evaluation results of foaming blow are shown in Table 1.

Example 6
Ethylene polymer (A-1), ethylene polymer (A-3) 90 parts by weight and ethylene polymer (B-1) (manufactured by Tosoh Corporation, trade name: Nipolon Hard, grade: 8600A) 10 weights The procedure was the same as in Example 1 except that the change was made to the part. The evaluation results of foaming blow are shown in Table 1.

Comparative Example 1
The same procedure as in Example 1 was conducted except that the ethylene polymer (A-1) was changed to the ethylene polymer (C-1). The evaluation results of foaming blow are shown in Table 1.

Comparative Example 2
The same procedure as in Example 1 was conducted except that the ethylene polymer (A-1) was changed to the ethylene polymer (D-1) (manufactured by Tosoh Corporation, trade name: TOSOH-HMS, grade: CK57). It was. The evaluation results of foaming blow are shown in Table 1.

  The foamed blow molded article of the present invention can be used as, for example, various containers, automobile members such as ducts, electrical product members, and building members.

Claims (2)

An ethylene-based polymer for foam blow molding (A) produced by a metallocene catalyst characterized by satisfying the following physical properties (a) to (d).
Physical property (a): Melt flow rate (MFR) at a temperature of 190 ° C. and a load of 2.16 kg is 0.05 g / 10 min or more and less than 1.0 g / 10 min Physical property (b): Density is 935 kg / m ³ or more Physical property (c ): The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) determined by gel permeation chromatography (GPC) is 6.0-15.
Physical property (d): Melt tension is 11.5-40 cN An ethylene polymer (B) produced by a Ziegler catalyst characterized by satisfying 10 to 99% by weight of the ethylene polymer (A) according to claim 1 and the following physical properties (e) to (h): 1) to 90% by weight (the sum of (A) and (B) is 100% by weight).
Physical property (e): Melt flow rate (MFR) at a temperature of 190 ° C. and a load of 2.16 kg is 0.01 g / 10 min or more and less than 1 g / 10 min Physical property (f): Density is 935 kg / m ³ or more Physical property (g): The ratio (Mw / Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) determined by gel permeation chromatography (GPC) is 6.0-30.
Physical property (h): Melt tension is 2.0 to 40 cN