JP5895482B2 - Ethylene polymer composition - Google Patents

Description

  The present invention relates to an ethylene polymer composition having good extrudability by blending an ethylene polymer with a processability modifier having good drawdown properties and excellent moldability improvement effect. .

  In general, high-pressure low-density polyethylene produced by the high-pressure radical method exhibits excellent film-forming properties during extrusion laminating and is suitable for use in extrusion laminating to various resin films, paper, base films such as aluminum foil Has been. In recent years, in fields where impact strength and puncture strength are required or in fields where heat resistance is required, high-pressure low-density polyethylene lacks performance, and linear low-density polyethylene and high-density polyethylene have come to be used. Is coming. However, since both linear low density polyethylene and high density polyethylene are inferior in extrusion laminate moldability, it is difficult to use them alone. Therefore, processability modifiers such as high pressure method low density polyethylene are mixed and used. It has been. As the processability modifier used for the polyolefin resin, high-pressure low-density polyethylene having high elasticity is often used. In order to make use of the properties of linear low density polyethylene and high density polyethylene, such processability modifiers are required to be able to improve extrusion laminate formability with as little mixing as possible. Since the higher the elasticity, the better the extrusion laminate formability can be improved with a small amount of mixing, there is a need for a workability modifier that is more effective than conventional high-pressure low-density polyethylene.

  Methods for increasing the elasticity of the polyolefin resin include a method of crosslinking the polyolefin resin with an electron beam and a method of crosslinking the polyolefin resin with a peroxide. According to this method, the elasticity of the polyolefin resin is excessive. Then, since the spreadability (drawdown) at the time of laminate molding deteriorates, there is a problem that the blending amount is limited (see Patent Documents 1 and 2).

  For these reasons, there has been a demand for a processability modifier that has good draw-down properties and excellent molding processability improvement effects.

Japanese Patent Laid-Open No. 08-301927 JP 09-104720 A

  The present invention has been made in view of the situation as described above, and is obtained by blending an ethylene-based polymer with a processability modifier having good drawdown property and excellent molding processability improvement effect. An ethylene polymer composition having moldability is provided.

The present invention has been found as a result of intensive studies on the above-described object. That is, the present invention is selected from the group consisting of high-density polyethylene, ethylene-α-olefin copolymers composed of repeating units derived from α-olefins having 3 to 8 carbon atoms, and high-pressure process low-density polyethylene satisfying (a). Containing 50 to 95% by weight of the ethylene-based polymer (A), 5 to 50% by weight of the high-pressure low-density polyethylene (B), and the high-pressure low-density polyethylene (B) satisfies (b) to (d). It is related with the ethylene-type polymer composition characterized by these.
(A) Ratio Mw / Mn of weight average molecular weight (hereinafter referred to as Mw) to number average molecular weight (hereinafter referred to as Mn) is less than 6 (b) Mw / Mn is 6 or more (c) Melt flow rate (hereinafter referred to as MFR) ) Measured at 95 ° C. for 1 to 10 g / 10 minutes (d) The chemiluminescence intensity after 5 minutes from the start of measurement is 40 counts / second or more per 1 g of pellets.

  The ethylene polymer (A) constituting the ethylene polymer composition of the present invention is a high density polyethylene, an ethylene-α-olefin copolymer composed of repeating units derived from an α-olefin having 3 to 8 carbon atoms, and Mw. / Mn is selected from the group consisting of high-pressure low-density polyethylene having a density of less than 6.

  Examples of high-density polyethylene include those produced by production processes such as gas phase polymerization, solution polymerization, slurry polymerization, and high-pressure ion polymerization using polymerization catalysts such as Ziegler catalysts and metallocene catalysts. it can.

  As an ethylene-α-olefin copolymer composed of a repeating unit derived from an α-olefin having 3 to 8 carbon atoms, a polymerization catalyst such as a Ziegler catalyst or a metallocene catalyst is used. Examples thereof include those produced by a production process such as a combination method, a slurry polymerization method, and a high-pressure ion polymerization method, but those produced using a metallocene catalyst are particularly preferable because they are excellent in mechanical strength when formed into a film. .

  Examples of the α-olefin constituting the ethylene-α-olefin copolymer include propylene, 1-butene, 1-hexene, 1-octene, and 4-methyl-1-pentene.

  Examples of the high-pressure method low-density polyethylene having an Mw / Mn of less than 6 include those produced by a radical polymerization method using a tubular reactor.

  Each resin can be obtained by purchasing a commercially available resin.

  The MFR of the ethylene polymer (A) is not particularly limited, but is preferably 1 to 100 g / 10 minutes, more preferably 5 to 50 g / 10 minutes, and most preferably 10 to 40 g / 10 minutes. If MFR is in the range of 1 to 100 g / 10 min, good moldability can be obtained by blending the high-pressure method low-density polyethylene (B) of the present invention.

The density of the ethylene polymer (A) is not particularly limited, but is preferably 880 to 970 kg / m ³ . If the density is within this range, good moldability can be obtained by blending the high-pressure low-density polyethylene (B) of the present invention.

  These resins may be used alone, or a plurality of resins may be mixed and used.

  The high-pressure method low density polyethylene (B) constituting the ethylene polymer composition of the present invention has Mw / Mn of 6 or more, preferably 7 or more. A case where Mw / Mn is less than 6 is not preferable because the melt tension of the high-pressure method low-density polyethylene is low and the effect of improving the laminate processability is small. The high pressure low density polyethylene (B) is preferably produced by an autoclave reactor.

  The high-pressure low-density polyethylene (B) constituting the ethylene polymer composition of the present invention has an MFR of 1 to 10 g / 10 minutes, preferably 1 to 5 g / 10 minutes. An MFR of less than 1 g / 10 minutes is not preferable because the extensibility during extrusion molding is reduced. Moreover, when MFR is larger than 10 g / 10min, since the melt tension of an ethylene-type polymer composition falls and a moldability deteriorates, it is unpreferable.

  MFR can be measured by the method described in JIS K6760 (1995).

  The high pressure low density polyethylene (B) constituting the ethylene polymer composition of the present invention has a chemiluminescence intensity measured at 95 ° C. at 5 minutes after the start of measurement of 40 counts / second or more per 1 g of pellets. When the chemiluminescence intensity is less than 40 counts / second per 1 g of pellets, the increase in elasticity of the ethylene polymer composition due to oxidation during the molding process is small, and good molding processability cannot be obtained.

  Chemiluminescence is weak light emitted when excited carbonyl or singlet oxygen generated when hydroperoxide (peroxide) decomposes changes to a stable state. Hydroperoxide is formed by oxidation of a substance, but generates a radical by decomposition, and thus is a substance that becomes the starting point of an oxidation reaction. Accordingly, a resin having high chemiluminescence intensity has many starting points for oxidation reaction, and hydroperoxide is easily decomposed by heat during molding and becomes highly elastic. By using a resin with high chemiluminescence intensity as the resin modifier, the extrusion load can be kept low during pelletization during production, which is often extruded at relatively low temperatures, while high elasticity is achieved at high temperatures during molding. Therefore, good moldability can be obtained.

  The chemiluminescence intensity can be measured using a chemiluminescence measuring device. In general, the intensity of chemiluminescence is gradually increased by heating the sample to a temperature at which hydroperoxide decomposes, and after the maximum value is exhibited, it is generally attenuated gradually. In the present invention, as a condition showing a value close to the maximum value, a value at a heating temperature of 95 ° C. and a measurement time of 5 minutes was used as a reference.

  The high-pressure method low-density polyethylene (B) constituting the ethylene polymer composition of the present invention preferably has a melt tension at 260 ° C. measured by a capillary viscometer of 150 mN or more, more preferably 160 mN or more. A melt tension of 150 mN or more is preferable because the melt tension of the ethylene polymer composition is increased and the moldability is improved.

The high pressure method low density polyethylene (B) constituting the ethylene polymer composition of the present invention preferably has a draw ratio of 4.7 or more, more preferably 9 when the melt tension is measured with a capillary viscometer at 260 ° C. .4 or more. When the draw ratio is 4.7 or more, the drawability becomes good, and a material mixed with an olefin resin such as linear low-density polyethylene or high-density polyethylene as a processability modifier is excellent in high-speed formation. Therefore, the method for obtaining the high-pressure method low-density polyethylene (B) constituting the ethylene polymer composition of the present invention is not particularly limited, but a method by melt kneading is desirable from the viewpoint of productivity and economy. As a method of melt kneading, there are a method in which processing is performed continuously and a method in which processing is performed in a batch manner. Examples of the apparatus include various kneaders such as a banbury mixer, a roll mixer, a kneader, a high-speed rotary mixer, and an extruder in addition to a single-screw extruder and a twin-screw extruder.

  The melt kneading temperature for obtaining the melt-kneaded high-pressure method low density polyethylene (B) is preferably 130 ° C. or higher and 220 ° C. or lower, more preferably 140 ° C. or higher and 220 ° C. or lower, more preferably 145 ° C. or higher and 200 ° C. or lower. . When the melt kneading temperature is 130 ° C. or higher and 220 ° C. or lower, the amount of hydroperoxide introduced into the high pressure method low density polyethylene after melt kneading is sufficient, and the deterioration of the high pressure method low density polyethylene during melt kneading is small. This is preferable because there is no fear of deteriorating the quality of the product due to gelation or coloring.

The oxygen concentration for obtaining the melt-kneaded high pressure method low density polyethylene (B) is preferably 0.1% or more and 21% or less. When the oxygen concentration is 0.1% or more and 21% or less, the amount of hydroperoxide introduced by melt-kneading is sufficient, and there is little deterioration of the high-pressure method low-density polyethylene during melt-kneading, and the product of Preferred because there is no risk of impairing the quality. The filling ratio of the resin in the kneading chamber at the time of melt kneading to obtain a melt-kneaded high-pressure low-density polyethylene (B) is preferably 40% or more and 90% or less, more preferably 45%. It is 90% or less. Here, the resin filling rate in the kneading chamber is the ratio of the molten resin in the space between the extruder barrel and the screw in the case of an extruder, and the space between the mixing chamber and the rotor in the case of a Banbury mixer. It refers to the proportion of molten resin in the interior. When the filling rate is 40% or more and 90% or less, the contact probability with oxygen is sufficiently secured, and the productivity is also favorable, which is preferable.

  The ethylene polymer composition of the present invention comprises 50 to 95% by weight of the ethylene polymer (A) and 5 to 50% by weight of the high pressure method low density polyethylene (B). The blending ratio of the high pressure method low density polyethylene (B) is more preferably 20 to 40% by weight. When the blending ratio of the high-pressure method low-density polyethylene (B) is less than 5%, the melt tension of the ethylene polymer composition is lowered and molding processability is deteriorated, which is not preferable. Moreover, when the compounding ratio of the high-pressure method low-density polyethylene (B) exceeds 50%, the drawdown property at the time of molding processing is lowered, which is not preferable.

  In the ethylene polymer composition of the present invention, a stabilizer, a lubricant, a flame retardant, a dispersant, a filler, a foaming agent, a foaming nucleating agent, and a crosslinking agent are included in the range not departing from the gist of the present invention. , UV inhibitors, antioxidants, colorants, and the like can be included. Moreover, it can also be used by mixing with other thermoplastic resins.

  For the ethylene polymer composition of the present invention, a method for forming a resin composition usually can be used. For example, as a melting / mixing method, extrusion kneading using a single screw extruder or a twin screw extruder, roll kneading. And the like, and can be obtained by melt-kneading by this method.

  The ethylene-based polymer composition of the present invention is suitably used for extrusion molding such as extrusion lamination molding, inflation film molding, cast film molding and the like. Among them, it is preferable to use it for extrusion laminate molding in which high elasticity is required for the workability modifier.

  The ethylene polymer composition of the present invention may be formed into a laminate by directly bonding a molten film made of an ethylene polymer composition extruded from a T die to a substrate by a known extrusion laminating machine. And having at least one layer made of the ethylene polymer composition of the present invention.

The extrusion laminate molding method may be any of single laminate, tandem laminate, coextrusion laminate, and sandwich laminate, and is not particularly limited. Moreover, when performing an extrusion laminating process, it is preferable to extrude from a die at a temperature of 250 to 350 ° C. in order to obtain a laminate having good adhesion between the substrate and the ethylene polymer composition layer. Further, at least the surface where the molten film of the ethylene polymer composition is in contact with the substrate may be oxidized with air or ozone gas. When the oxidation reaction with air proceeds, it is preferable to extrude from a die at a temperature of 270 ° C. or higher, and when the oxidation reaction with ozone gas proceeds, it is preferable to extrude at 250 ° C. or higher. In addition, it is preferable that the processing amount of ozone gas is 0.5 mg or more per 1 m ^{2 of} the film extruded from the die. Moreover, in order to improve adhesiveness with a base material, you may perform well-known surface treatments, such as an anchor-coat agent process, a corona discharge process, a flame process, and a plasma process, to the adhesion surface of a base material.

  Examples of the substrate include synthetic polymer film and sheet, woven fabric, non-woven fabric, metal foil, paper, cellophane and the like. Examples thereof include films and sheets made of a synthetic polymer such as polyethylene terephthalate, polyamide, polyvinyl alcohol, polycarbonate, polyethylene, and polypropylene. Further, these polymer films and sheets may be further subjected to aluminum vapor deposition, alumina vapor deposition, or silicon dioxide vapor deposition. Further, these polymer films and sheets may be further printed using urethane-based ink or the like. Examples of the metal foil include aluminum foil and copper foil, and examples of the paper include kraft paper, stretched paper, high-quality paper, glassine paper, board paper such as cup base paper and photographic paper base paper.

  The present invention provides an ethylene polymer composition having good extrudability by blending an ethylene polymer with a processability modifier having good drawdown properties and excellent moldability improvement effect. It can be used over a wide range as a film, container, tape, and support, and is extremely useful as an industrial material.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

The evaluation methods for physical properties and workability are described below.
(1) Density Density was measured by a density gradient tube method in accordance with JIS K6760 (1995).
(2) MFR
MFR was measured with a melt indexer according to JIS K6760 (1995).
(3) Number average molecular weight (Mn) and weight average molecular weight (Mw)
The number average molecular weight (Mn) and the weight average molecular weight (Mw) were measured by the GPC method.

  A solvent in which 0.1% of BHT (manufactured by Wako Pure Chemical Industries, Ltd.) is added as an antioxidant to HPLC grade 1,2,4-trichlorobenzene (manufactured by Wako Pure Chemical Industries, Ltd.) after weighing the measurement sample. In addition to the sample solution, the sample solution was dissolved by shaking at 140 ° C. for 1 hour.

Using Tosoh Co., Ltd. HLC-8121GPC / HT as a measuring device, it measured as follows. Three TSKgelGMHHR-H (20) HT (manufactured by Tosoh Corporation, inner diameter 7.8 mm, length 30 cm) were connected and used as a separation column. For the moving layer, HPLC grade 1,2,4-trichlorobenzene (Wako Pure Chemical Industries, Ltd.) with 0.05% BHT (Wako Pure Chemical Industries, Ltd.) added as an antioxidant is used. And moved through a separation column maintained at 140 ° C. at a flow rate of 1.0 mL / min. 0.3 mL of a sample solution whose concentration was adjusted to 1.0 mg / mL was injected into this, and sample components separated by a differential refractometer were detected. A molecular weight distribution curve, a number average molecular weight (Mn), and a weight average molecular weight (Mw) were calculated using a quintic approximation curve prepared using standard polystyrene (manufactured by Tosoh Corporation) as a calibration curve.
(4) Melt tension For melt tension, a capillary viscometer (Toyo Seiki Seisakusho, trade name: Capillograph) with a barrel diameter of 9.55 mm is equipped with a die with a length of 8 mm, a diameter of 2.095 mm, and an inflow angle of 90 °. did. The temperature was set to 260 ° C., the piston lowering speed was set to 10 mm / min, the stretch ratio was set to 4.7, and the load (mN) required for take-up was the melt tension. When the maximum draw ratio was less than 4.7, the drawability was poor and it was determined to be unsuitable as a workability modifier. The measurement was performed in a constant temperature room set at 23 ° C.
(5) Chemiluminescence intensity Using a chemiluminescence measuring device (Tohoku Electronics Industry, trade name: Chemiluminescence Analyzer CLA-ID3), about 4 g of the sample is placed in the sample chamber and the chemiluminescence intensity is measured at 95 ° C. The chemiluminescence intensity 5 minutes after the start was taken as the measured value.
(6) Oxygen concentration In the case of an extruder, the oxygen concentration in the mixing chamber immediately before kneading was measured using an oxygen concentration meter (XP-3180 manufactured by Shin Cosmos Electric Co., Ltd.) in the case of a Banbury mixer.
(7) Filling rate In the case of an extruder, the volume of the space between the extruder barrel and the screw is calculated. In the case of a Banbury mixer, the volume of the space between the mixing chamber and the rotor is calculated. The volume was calculated by dividing by the volume of space.
(8) Neck-in The ethylene polymer composition is supplied to an extruder of an extrusion laminator (Musashinokikai) having a 90 mm diameter screw and extruded from a T die having an opening width of 600 mm at a temperature of 340 ° C. The width of the T-die opening and the ethylene polymer composition when the extrusion laminating resin composition is 10 μm thick on a kraft paper substrate having a basis weight of 50 g / m ² at 200 m / min. The difference from the coat width was defined as neck-in, and the value was measured.
(9) Drawdown Kraft paper having a basis weight of 50 g / m ² from a T-die having an opening width of 600 mm at a temperature of 340 ° C. by feeding the ethylene polymer composition to an extruder of an extrusion laminator (Musashinokikai) having a 90 mm diameter screw. When the extrusion rate of the base material was gradually increased at a constant screw rotation speed of 10 when extruded onto the base material, the take-up speed when the film of the ethylene polymer composition was broken was drawn down, and the value was It was measured.

Example 1
As a kneading machine, an intermeshing screw, a counter-rotating twin screw extruder (Toyo Seiki Seisakusho, trade name: Labo Plast Mill 2D25S type), MFR 3.0 g / 10 min, density 924 kg / m ³ , Mw / Mn 6 .5 high pressure method low density polyethylene (Tosoh Co., Ltd., Petrocene 205) was melt-kneaded to prepare high pressure method low density polyethylene (B-1). The conditions at that time were a kneading temperature of 160 ° C., a discharge rate of 1.7 kg / hour, and an oxygen concentration of 21%. The filling rate at this time was 80%. The screw used was a multi-strip flight type with a reverse lead (2S25R type). Table 2 shows kneading conditions and physical properties of the kneaded product.

High-density polyethylene (trade name Nipolon Hard 1000 manufactured by Tosoh Corporation; density 966 kg / m ³ , MFR 20 g / 10 min) as an ethylene polymer with respect to 25% by weight of this high-pressure low-density polyethylene (B-1) (A-1).) A blend of 75% by weight and dry blended with a rotary tumbler was melt-kneaded using a 50 mm diameter single screw extruder (Placo) set at 180 ° C. to ethylene. A system polymer composition was obtained. The obtained ethylene polymer composition was laminated by the method shown in the evaluation method, and neck-in and draw-down were measured. These evaluation results are shown in Table 3.

Example 2
An ethylene-α-olefin copolymer (trade name Nipolon L M65, manufactured by Tosoh Corporation; density 920 kg / m ³ , MFR 20 g / 10 minutes) as the ethylene polymer (A) (hereinafter referred to as (A-2)). Except that was used, pellets of an ethylene polymer composition were obtained in the same manner as in Example 1. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 3.

Example 3
Except that an ethylene-α-olefin copolymer (density 925 kg / m ³ , MFR 24 g / 10 min) (hereinafter referred to as (A-3)) was used as the ethylene polymer (A), it was the same as in Example 1. Thus, pellets of the ethylene polymer composition were obtained. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 3.

  In addition, an ethylene-alpha-olefin copolymer (A-3) is manufactured by the synthesis example 1 shown below.

Synthesis example 1
[Preparation of modified hectorite]
After adding 3 liters of ethanol and 100 ml of 37% concentrated hydrochloric acid to 3 liters of water, 585 g (1.1 mol) of N-methyl-dioleylamine was added to the resulting solution and heated to 60 ° C. to form the hydrochloride salt. A solution was prepared. 1 kg of hectorite was added to this solution. The suspension was stirred at 60 ° C. for 3 hours, the supernatant was removed, and then washed with 50 L of 60 ° C. water. Then, it dried at 60 degreeC and 10 < ^-3 > torr for 24 hours, and the modified | denatured hectorite with an average particle diameter of 5.2 micrometers was obtained by grind | pulverizing with a jet mill.
[Preparation of polyethylene resin production catalyst]
500 g of the modified hectorite was suspended in 1.7 liters of hexane, and 8.25 g (20.0 mmol) of dimethylsilanediyl (cyclopentadienyl) (2-methylindenyl) zirconium dichloride and a hexane solution of triisobutylaluminum ( 0.714M) Add 2.8 liters (2 mol) of mixture, stir at 60 ° C. for 3 hours, let stand and remove supernatant, add triisobutylaluminum in hexane (0.15M) Thus, a macromonomer synthesis catalyst (100 g / L) was obtained.

In the macromonomer synthesis catalyst prepared above, 10 mol% of isopropylidene (1-cyclopentadienyl) (2,7-di-) with respect to dimethylsilanediyl (cyclopentadienyl) (2-methylindenyl) zirconium dichloride is used. 1.21 g (2.22 mmol) of t-butyl-9-fluorenyl) zirconium dichloride was added and stirred at room temperature for 6 hours. The supernatant was removed by standing, and a hexane solution (0.15 M) of triisobutylaluminum was added to finally obtain a 100 g / L polyethylene resin production catalyst.
[Production of ethylene-α-olefin copolymer (A-3)]
In a polymerization vessel having an internal volume of 540 L, the above-mentioned [145 kg / hour of hexane, 33.0 kg / hour of ethylene, 4.9 kg / hour of butene-1, 20 NL / hour of hydrogen and 30 kg / hour of polymer production] The polyethylene resin production catalyst prepared in [Preparation of polyethylene resin production catalyst] was continuously supplied, and the polymerization reaction was continuously carried out while maintaining the total pressure at 3,000 kPa and the polymerization vessel internal temperature at 60 ° C. The slurry was continuously extracted from the polymerization vessel to remove unreacted hydrogen, ethylene, and butene-1, and then separated and dried to obtain an ethylene-α-olefin copolymer (A-3) powder. This was melt-kneaded using a single-screw extruder having a diameter of 50 mm set at 200 ° C. and pelletized to obtain ethylene-α-olefin copolymer (A-3) pellets. The density of the obtained ethylene-α-olefin copolymer (A-3) pellets was 925 kg / m ³ , MFR was 24 g / 10 min, the number of long chain branches was 0.13 per 1000 carbon atoms, and the weight average molecular weight ( The ratio Mw / Mn between Mw) and the number average molecular weight (Mn) was 3.8.

Example 4
A high pressure method low density polyethylene (B-2) was prepared under the same conditions as in Example 1 except that the kneading temperature was 200 ° C. Except that this high pressure method low density polyethylene (B-2) was used in place of the high pressure method low density polyethylene (B-1), pellets of an ethylene polymer composition were obtained in the same manner as in Example 1. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 3.

Example 5
A high-pressure low-density polyethylene (B-3) was prepared under the same conditions as in Example 1 except that the oxygen concentration was 5%. Except that this high pressure method low density polyethylene (B-3) was used instead of the high pressure method low density polyethylene (B-1), pellets of an ethylene polymer composition were obtained in the same manner as in Example 1. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 3.

Example 6
A high pressure method low density polyethylene (B-4) was prepared under the same conditions as in Example 1 except that the filling rate was 50%. Except that this high pressure method low density polyethylene (B-4) was used instead of the high pressure method low density polyethylene (B-1), pellets of an ethylene polymer composition were obtained in the same manner as in Example 1. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 3.

Example 7
Except that the blending ratio of the ethylene polymer composition was changed to 90% by weight of A-1 and 10% by weight of B-1, pellets of the ethylene polymer composition were obtained in the same manner as in Example 1. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 3.

Example 8
The pellets of the ethylene polymer composition were obtained in the same manner as in Example 1 except that the blending ratio of the ethylene polymer composition was changed to A-1 55 wt% and B-1 45 wt%. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 3.

Comparative Example 1
A high-pressure low-density polyethylene (B-5) was prepared under the same conditions as in Example 1 except that nitrogen was introduced into the extruder so that the oxygen concentration was less than 0.1%. Except that this high pressure method low density polyethylene (B-5) was used instead of the high pressure method low density polyethylene (B-1), pellets of an ethylene polymer composition were obtained in the same manner as in Example 1. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 4.

  The ethylene polymer composition had a very large neck-in and was inferior in laminate processability.

Comparative Example 2
A high-pressure low-density polyethylene (B-6) was prepared under the same conditions as in Example 1 except that the discharge rate was 2.2 kg / hour and the filling rate was 98%. An ethylene polymer composition pellet was obtained in the same manner as in Example 1 except that this high pressure method low density polyethylene (B-6) was used instead of the high pressure method low density polyethylene (B-1). The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 4.

  The ethylene polymer composition had a very large neck-in and was inferior in laminate processability.

Comparative Example 3
Except that the high-pressure low-density polyethylene (B) was not blended, a pellet of an ethylene polymer composition was obtained in the same manner as in Example 1. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 4.

The ethylene polymer composition had a very large neck-in and was inferior in laminate processability.
Comparative Example 4
High pressure method low density polyethylene (trade name Petrocene 360; density 919 kg / m ³ , MFR 1.6 g / 10 min) (hereinafter referred to as (B-7)) manufactured by Tosoh Corporation as the high pressure method low density polyethylene (B). used. B-7 was used without melt kneading, and B-7 25 wt% was blended with A-1 75 wt% to obtain an ethylene polymer composition pellet in the same manner as in Example 1. The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 4.

  The ethylene-based polymer composition was inferior in the drawdown property and inferior in the laminate processability.

Comparative Example 5
A high-pressure low-density polyethylene under the same conditions as in Example 1 except that Petrocene 180 (Made in Tosoh Corporation, MFR 2.0 g / 10 min, density 924 kg / m ³ , Mw / Mn 4.8) was used instead of Petrocene 205. (B-8) was prepared. An ethylene polymer composition pellet was obtained in the same manner as in Example 1 except that this high pressure method low density polyethylene (B-8) was used instead of the high pressure method low density polyethylene (B-1). The obtained pellets were laminated and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 4.

  The ethylene polymer composition had a very large neck-in and was inferior in laminate processability.

Claims (4)

High density polyethylene, ethylene-α-olefin copolymer composed of repeating units derived from α-olefin having 3 to 8 carbon atoms, and ethylene polymer selected from the group consisting of high-pressure low-density polyethylene satisfying (a) (A) 50 to 95% by weight, high pressure method low density polyethylene (B) 5 to 50% by weight, and high pressure method low density polyethylene (B) satisfies (b) to (d) -Based polymer composition.
(A) Ratio Mw / Mn of weight average molecular weight Mw and number average molecular weight Mn is less than 6 (b) Mw / Mn is 6 or more (c) MFR is 1 to 10 g / 10 min (d) Measurement measured at 95 ° C The chemiluminescence intensity 5 minutes after the start is 40 counts / second or more per gram of pellets 2. The ethylene-based polymer composition according to claim 1, wherein the high-pressure low-density polyethylene (B) satisfies (e) to (f).
(E) The melt tension at 260 ° C. measured with a capillary viscometer is 150 mN or more (f) The stretch ratio when the melt tension is measured with a capillary viscometer at 260 ° C. is 4.7 or more. A method for producing an ethylene-based polymer composition, wherein the high-pressure method low-density polyethylene (B) is melt-kneaded under conditions satisfying the following conditions (g) to (i).
(G) The kneading temperature is 130 ° C. or higher and 220 ° C. or lower (h) The oxygen concentration is 0.1% or higher and 21% or lower (i) The filling rate of the molten resin in the kneading chamber is 40% or higher and 90% or lower. A laminate comprising at least one layer made of the ethylene polymer composition according to claim 1 .