JP2006272587A - Extrusion-laminated laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminate which can optionally change heat resistance, gas-barrier properties, and rigidity and is reduced in thickness nonuniformity. <P>SOLUTION: In extrusion-lamination molding, a composition comprising 1-99 wt.% of polyethylene (A) which satisfies the following requirements: (1) a density is 900-975 kg/m<SP>3</SP>, (2) a melt mass flow rate is 0.01-100 g/10 min, (3) Mw/Mn is at least 3.0, (4) (Mz/Mw)-(Mw/Mn) is at least 0.5, (5) the content of a composition with a molecular weight of at least 10<SP>6</SP>g/mole from a molecular weight pattern is 0.1-5.0 wt.% of the total polymer weight, and (6) the relationship of a half-value breadth (log (MH/ML))<1.1 from the molecular weight pattern is satisfied and 99-1 wt.% of low density polyethylene (B) which satisfies the following requirements: (7) a density is 910-930 kg/m<SP>3</SP>and (8) a melt mass flow rate is 0.1-100 g/10 min is extrusion lamination-molded as at least one layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ethylene homopolymer having a specific molecular weight distribution pattern spreading on the high molecular weight side or an ethylene / α-olefin copolymer composed of ethylene and an α-olefin having 3 to 20 carbon atoms, and a high-pressure radical weight. The present invention relates to an extruded laminate having at least one polyethylene-based resin composition made of legal low density polyethylene.

  Laminates with one layer of polyethylene consist of packaging for dry food and beverages, pharmaceutical packaging such as medicine and infusion bags, toiletries such as shampoos, cosmetics, and diaper backsheets, photographic paper supports, paper containers and Widely used, such as lids, paper plates, release paper and release tape, moisture-proof paper, and paper semi-retort packs. In order to obtain these laminates, extrusion lamination molding is preferred because the molding method is easy and the cost performance is excellent.

Conventionally, the polyethylene resin used in these laminates has been mainly branched low-density polyethylene (LDPE) because of its excellent moldability. However, the density of LDPE is generally 918 to 925 kg / m ³ , and it is difficult to change physical properties that change with the density, such as heat resistance, rigidity, gas barrier properties, and the like, which has been limited in use. On the other hand, linear polyethylene such as linear low density polyethylene (L-LDPE) and high density polyethylene (HDPE) can be widely varied in density depending on the number of short chain branches. Because of poor properties, it was difficult to obtain a laminate by extrusion lamination. Therefore, a method of obtaining a laminate by extrusion-laminating a mixture of linear polyethylene and LDPE is often used (for example, see Patent Documents 1 to 4).

JP-A-6-65443 JP-A-6-322189 JP-A-7-92610 However, in JP-A-2000-73018, since the mixing ratio of LDPE is 1 to 40%, the extrusion load at the time of molding the laminate is large, and the production rate cannot be increased. Had the problem of poor cost performance. In Patent Documents 2 and 4, since the mixing ratio of LDPE is 50% or more, a laminate excellent in heat resistance, rigidity, gas barrier properties and the like cannot be obtained. Furthermore, in Patent Document 3, polyethylene obtained by a metallocene catalyst, polyethylene obtained by a metal catalyst other than a metallocene, and a mixture of LDPE have been proposed, but when the ratio of LDPE is small, molding processability is poor, It was difficult to obtain a laminate excellent in cost performance, and when the ratio of LDPE was large, a laminate excellent in heat resistance, rigidity, gas barrier properties and the like could not be obtained.

  As described above, it has been impossible to satisfy both excellent cost performance and heat resistance in the laminate obtained by the methods proposed so far.

  The present invention has been made to solve the above-described problems of the prior art, and is a laminate comprising a polyethylene resin having at least one layer that is excellent in extrusion lamination processability and easy in density adjustment. Is to provide.

  As a result of intensive studies to solve the above problems, the inventors of the present invention have adjusted the density of an ethylene resin composition obtained by blending a specific ethylene polymer with high-pressure radical polymerization low-density polyethylene. Has been found to be easy, the load during extrusion laminating is small, the production rate can be increased, and a laminate can be formed, and the above-mentioned problems have been solved.

That is, the present invention relates to an ethylene homopolymer that satisfies the following requirements (1) to (6), or an ethylene / α-olefin copolymer (A) 1 to 1 composed of ethylene and an α-olefin having 3 to 20 carbon atoms. 99% by weight and an extruded laminate having at least one layer of a polyethylene resin composition comprising 99 to 1% by weight of low density polyethylene (B) obtained by a high-pressure radical polymerization method satisfying (7) and (8) It is.
(1) Density is 900-975 kg / m ³
(2) Melt mass flow rate of 0.01 to 100 g / 10 min (3) Mw / Mn determined by gel permeation chromatography (GPC) measurement is 3.0 or more (4) Gel permeation chromatography (MPC) satisfying the relationship of (Mz / Mw) − (Mw / Mn) ≧ 0.5 determined by measurement (5) Molecular weight 1 million g from the molecular weight pattern obtained by gel permeation chromatography (GPC) measurement / Molecular molecular weight component is 0.1 to 5.0% by weight of the total weight of the polymer
(6) The molecular weight pattern obtained by gel permeation chromatography (GPC) measurement satisfies the relationship of half width (Log (MH / ML)) <1.1. (7) Density is 910 to 930 kg / m ³
(8) Melt mass flow rate is 0.1 to 100 g / 10 min. The present invention is described in detail below.

  The ethylene-based polymer (A) according to the present invention is an ethylene homopolymer or an ethylene / α-olefin copolymer obtained by polymerizing ethylene and an α-olefin having 3 to 20 carbon atoms.

  Examples of the α-olefin having 3 to 20 carbon atoms include propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, 3-methyl-1-butene, vinylcycloalkane, styrene, and ethylidene norbornene. Etc. can be illustrated. Further, two or more kinds of these α-olefins can be mixed and used.

The density of the ethylene-based polymer (A) according to the present invention is a value measured by a density gradient tube method according to JIS K6922-1 (1997), and is 900 to 975 kg / m ³ . Moreover, it is preferable that it is 950-975 kg / m < ³ > for the use for which heat resistance, moisture-proof property, and rigidity are calculated | required. When it exceeds 975 kg / m ³ , curling of the obtained laminate may be remarkable. On the other hand, if the density is less than 900 kg / m ³ , stickiness of the obtained laminate may be remarkable.

  The melt mass flow rate (MFR, load 2.16 kg, temperature 190 ° C. condition) of the ethylene polymer (A) according to the present invention is in accordance with JIS K6922-1 (1997), manufactured by Toyo Seiki Seisakusho. ), 0.01 to 100 g / 10 min, preferably 0.1 to 80 g / 10 min, more preferably 0.5 to 60 g / 10 min. If the MFR is larger than 100 g / 10 minutes, the film formation stability during the lamination process is deteriorated, which may cause unevenness in the thickness of the obtained laminate. On the other hand, if it is less than 0.01 g / 10 min, curling of the laminate becomes remarkable, which is not preferable.

  The weight average molecular weight (Mw), number average molecular weight (Mn), Z average molecular weight (Mz) of the ethylene-based polymer (A) according to the present invention, and their ratios Mw / Mn and Mz / Mw are gel perm It was measured by an association chromatography (GPC). Tosoh Co., Ltd. HLC-8121GPC / HT is used as the GPC apparatus, Tosoh Co., Ltd. TSKgel GMHhr-H (20) HT is used as the column, the column temperature is set to 140 ° C., and 1 is used as the eluent. It was measured using 2,4-trichlorobenzene. 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 used was calibrated by a universal calibration method using a polystyrene sample having a known molecular weight. The Mw / Mn of the ethylene polymer of the present invention is 3.0 or more, more preferably 3.5 or more. If Mw / Mn is less than 3.0, the shear stress applied to the resin under a high shear rate at the time of molding increases, which causes a problem in workability such as an increase in extrusion load, and a laminate may not be obtained. .

  The ethylene-based polymer (A) according to the present invention shows a relationship of (Mz / Mw) − (Mw / Mn) ≧ 0.5, and the molecular weight distribution clearly spreads on the high molecular weight side in the GPC chart. Is a feature. As a result, an effect peculiar to the fluidity at the time of melting is brought out, and good moldability is obtained, so that a laminate with little thickness unevenness can be obtained.

  The ethylene polymer (A) according to the present invention is characterized in that a molecular weight component having a molecular weight of 1,000,000 g / mol or more is 0.1 to 5.0% by weight of the total weight of the polymer from a molecular weight pattern obtained from GPC. To do. When the molecular weight component having a molecular weight of 1,000,000 g / mol or more is less than 0.1% by weight of the total weight of the polymer, uneven thickness occurs in the resulting laminate, and when it exceeds 5.0% by weight, Problems such as the generation of wax occur.

  The ethylene-based polymer (A) according to the present invention satisfies the relationship of half width (Log (MH / ML)) <1.1 from the molecular weight pattern obtained by GPC measurement, and more preferably half width (Log (MH / ML)). ML)) <1.05 is satisfied. By satisfying this relationship, the laminate exhibits an excellent surface appearance. Here, the half-value width of the molecular weight pattern indicates the spread of the spectrum (degree of molecular weight distribution) around the peak top (maximum frequency) of the maximum peak among the molecular weight distribution patterns in GPC. That is, the width of the GPC spectrum line where the intensity in the spectrum is half the peak top (maximum frequency) (each having a high molecular weight side is MH and the low molecular weight side is ML) is the half-value width. In addition, when a plurality of peaks are observed, calculation is performed from the maximum one of the peaks.

  In the GPC pattern of the ethylene-based polymer (A) according to the present invention, the number of maximum values of the molecular weight distribution is not particularly limited, but preferably has a single maximum value. Those having a plurality of maximum values make it difficult to control the thickness of the laminate.

  The method for producing the ethylene polymer (A) according to the present invention is not particularly limited. For example, in the presence of a Ziegler catalyst, a Phillips catalyst or a metallocene catalyst, ethylene is polymerized alone or ethylene and an α-olefin having 3 to 20 carbon atoms are produced. The method of making it copolymerize is mentioned. Among them, for example, an ethylene heavy polymer obtained in the presence of a metallocene catalyst described in JP-A-7-224106, JP-A-9-59310, JP-A-10-223112, JP-A-10-231313, etc. The coalescence is preferable because the low molecular weight component contained in the polymer is small and the stickiness of the laminate surface is reduced.

  The ethylene polymer (A) according to the present invention is produced by slurry polymerization or gas phase polymerization. The ethylene polymer is preferably obtained by polymerization in a single reactor. Particularly preferably, it is continuously produced in a single reactor, and further produced by a method of separating and purifying continuously produced ethylene polymer and unreacted monomers, polymerization aids and solvents. The The solvent for slurry polymerization may be any organic solvent that is generally used, and specific examples include benzene, toluene, xylene, propane, butane, pentane, hexane, heptane, cyclohexane, and methylene chloride. .

  There are no particular restrictions on the polymerization conditions such as polymerization temperature, polymerization time, polymerization pressure, and monomer concentration in producing the ethylene-based polymer (A) using the olefin polymerization catalyst shown in the present invention. In this case, the polymerization temperature is −100 to 100 ° C., preferably 0 to 100 ° C., the polymerization time is preferably 10 seconds to 20 hours, and the polymerization pressure is preferably in the range of normal pressure to 10 MPa. It is also possible to adjust the molecular weight using hydrogen during polymerization. In the case of gas phase polymerization, the polymerization temperature is preferably −100 to 120 ° C., preferably 0 to 110 ° C., the polymerization time is 10 seconds to 20 hours, and the polymerization pressure is preferably in the range of normal pressure to 10 MPa. It is also possible to adjust the molecular weight using hydrogen during polymerization. Among these, slurry polymerization is more preferable in view of the removal rate of wax components and the like.

  The high-pressure radical polymerization method low density polyethylene (B) according to the present invention is a polyethylene produced by a high-pressure radical polymerization method, and is obtained by polymerizing ethylene by a known method.

The density of the high-pressure radical polymerization process low-density polyethylene (B) according to the present invention is a 910~930kg / ^{m 3,} preferably 915~928kg / ^{m 3,} more preferably from 917~925kg / ^{m 3.} When the density exceeds 930 kg / m ³ , uneven thickness occurs in the laminate. On the other hand, when the density is less than 910 kg / m ³ , the self-adhesiveness of the laminate is increased, which may cause blocking, which is not preferable.

  The melt mass flow rate (MFR, load 2.16 kg, temperature 190 ° C. condition) of the high pressure radical polymerization method low density polyethylene (B) according to the present invention is 0.1 to 100 g / 10 min, preferably 0.5 to 70 g. / 10 minutes, more preferably 1.0 to 50 g / 10 minutes. An MFR of less than 0.1 g / 10 minutes is not preferable because the appearance of the laminate is deteriorated. On the other hand, when the MFR exceeds 100 g / 10 min, the yield in obtaining the laminate is deteriorated, so that a laminate excellent in cost performance cannot be obtained.

  In addition, the high pressure radical polymerization method low density polyethylene (B) according to the present invention is not limited to the purpose of the present invention, and other α-olefin, vinyl acetate, acrylate ester and other polymerizable monomers can be used. The copolymer may be used.

  The polyethylene resin composition used as at least one layer constituting the laminate of the present invention comprises the ethylene polymer (A) and the high-pressure radical polymerization method low-density polyethylene (B). The mixing ratio is more preferably in the range of 99: 1 to 1:99 by weight ratio ((A) :( B)) of the ethylene polymer (A) and the high-pressure radical polymerization method low-density polyethylene (B). Is in the range of 99: 1 to 10:90, more preferably in the range of 99: 1 to 30:70, and particularly preferably in the range of 99: 1 to 70:30, whereby excellent mechanical properties are obtained. A laminated body is obtained.

The polyethylene-based resin composition used as at least one layer constituting the laminate of the present invention preferably has a density measured according to JIS K6922-1 (1997) of 950 to 975 kg / m ³ , whereby heat resistance A laminate having excellent rigidity and moisture resistance can be obtained.

  The polyethylene resin composition used as at least one layer constituting the laminate of the present invention has a melt mass flow rate measured according to JIS K6922-1 (1997) of 1 to 100 g / 10 min. Desirable for reducing thickness unevenness.

  The polyethylene resin composition used as at least one layer constituting the laminate of the present invention is 160 ° C., die L / D = 8 / 2.095 (mm), cylinder diameter 9.55 mm, piston lowering speed 10 mm / min. The swell ratio measured in (1) is preferably 1.2 or more and 3.0 or less in order to reduce the yield of the laminate.

  The polyethylene-based resin composition used as at least one layer constituting the laminate of the present invention has an antioxidant, an anti-aging agent, a heat stabilizer, a weather resistance stabilizer, and an ultraviolet absorber as long as the object of the present invention is not impaired. Additives such as additives, chlorine absorbers, antistatic agents, antifogging agents, slip agents, lubricants, antiblocking agents, nucleating agents, pigments, dyes, plasticizers, flame retardants, inorganic fillers, organic fillers, etc. It can be blended accordingly. It can also be mixed with other thermoplastic resins. Examples of these are tackifying resins, waxes, polypropylene resins, polybutenes, poly-4-methyl-1-pentene, ethylene / vinyl acetate copolymers, ethylene / ethyl acrylate copolymers, ethylene / vinyl alcohol copolymers. , Polystyrene, ethylene / methyl methacrylate copolymer, ionomer, or a maleic anhydride graft product thereof.

  The polyethylene-type resin composition used as at least one layer which comprises the laminated body of this invention can be manufactured using a well-known method. For example, a method of mixing and kneading each component using various kneaders such as a Banbury mixer, a roll mixer, a kneader, a high-speed rotary mixer, and an extruder, preferably a single screw or twin screw extruder can be used. Also, the pellets mixed by dry blending can be kneaded and used during extrusion lamination molding. However, when stability of quality is required, it is preferable to melt and mix in advance before extrusion lamination.

The laminate of the present invention can be obtained by laminating and / or coating a polyethylene-based resin composition forming at least one layer on various substrates by an extrusion laminate molding method. 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 lamination process, in order to obtain the laminated body with the favorable adhesiveness of a base material and a polyethylene layer, it is preferable to extrude from a die | dye at the temperature of 250-350 degreeC. Moreover, at least the surface in contact with the substrate of the molten film of the polyethylene resin composition 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. For example, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polylactic acid, polyamides such as nylon 6 and nylon 66, high density polyethylene, low density polyethylene, linear low density polyethylene, ethylene / ethyl acrylate copolymer, ethylene・ Methacrylic acid copolymers, ethylene / vinyl acetate copolymers, ethylene / vinyl alcohol copolymers, polyethylene resins such as ionomers, polypropylene resins, polyolefin resins such as polybutene and polymethylpentene, acrylic resins, polyvinyl Examples thereof include films and sheets made of a synthetic polymer such as alcohol, polyvinyl chloride, polyvinylidene chloride, polystyrene, polycarbonate, polyurethane, and cellulose resin. 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 ink, acrylic 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 thickness of the laminate of the present invention is not particularly limited, but the thickness of the extruded laminate layer is preferably in the range of 3 to 200 μm from the viewpoints of economy and workability.

Laminates of the present invention are dried foods such as snacks and instant noodles, soups, miso, pickles, sauces, aquatic food and beverage packaging such as beverages, medicine packaging such as medicines and infusion bags, shampoos, cosmetics, diaper back sheets Can be used as a wide range of films, containers, tapes, supports, such as toiletries, photographic paper supports, paper containers and lids, paper plates, release papers and release tapes, moisture-proof paper, paper semi-retort packs, etc. . In particular, a laminate obtained by extrusion laminating a polyethylene resin composition having a density of 950 to 980 kg / m ³ includes a heat-resistant container, a gas barrier container, a release paper and a release tape, a photographic paper support, and moisture-proof paper. Used in preference.

  The laminate of the present invention can be arbitrarily changed in heat resistance, gas barrier properties, and rigidity simply by changing the density of the polyethylene-based resin to be used, and has excellent thickness unevenness.

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

  In the present invention, the physical properties were evaluated as follows.

~density~
Measured according to JIS K6922-1 (1997).

~ Melt Mass Flow Rate (MFR) ~
Measured according to JIS K6922-1 (1997).

~ Average molecular weight, molecular weight distribution ~
The weight average molecular weight (Mw), number average molecular weight (Mn), Z average molecular weight (Mz) and their ratios Mw / Mn and Mz / Mw were measured by gel permeation chromatography (GPC). Tosoh Co., Ltd. HLC-8121GPC / HT is used as the GPC apparatus, Tosoh Co., Ltd. TSKgel GMHhr-H (20) HT is used as the column, the column temperature is set to 140 ° C., and 1 is used as the eluent. It was measured using 2,4-trichlorobenzene. 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 used was calibrated by a universal calibration method using a polystyrene sample having a known molecular weight.

~ Swell ratio ~
The swell ratio is a capillary viscometer (Toyo Seiki Seisakusho, trade name: Capillograph) with a barrel diameter of 9.55 mm, and a die with a length (L) of 8 mm, a diameter (D) of 2.095 mm, and an inflow angle of 90 °. Wearing and measuring. The diameter of the melt-extruded product was measured with a laser beam provided and obtained by dividing by the die diameter (2.095 mm).

-Thickness variation of the laminate-
The thickness of the central part of the laminate was measured at 30 points every 10 cm using a micrometer. The difference between the thickest point and the thinnest point was obtained and used as an index of thickness unevenness.

-Heat resistant pinhole property-
The laminate was left in a small oven (Werner Mathis AG) set at 135 ° C. for 5 seconds and then taken out. A methylene blue solution was applied to the heat-treated laminate, and the state after wiping it off was visually observed to count the number of pinholes generated.

Reference Example 1 Production of High Density Polyethylene (A1) The polymerization operation, reaction and solvent purification were all performed under an inert gas atmosphere. Moreover, the solvent etc. which were used for the reaction were all purified, dried and deoxygenated by a known method in advance. Furthermore, the compound used for the reaction was synthesized and identified by a known method.

[Preparation of modified clay compound]
Methyl dioctadecylamine; (C ₁₈ H ₃₇ ) ₂ (CH ₃ ) N 536 g, water 4.8 L, ethanol 3.2 L was added to 37% hydrochloric acid 83.3 mL, and methyl dioctadecylamine hydrochloride solution was added. Prepared. To this solution, 1000 g of synthetic hectorite was added and reacted at 60 ° C. for 3 hours. The reaction solution was filtered off and the solid component was washed with water. The solid component was dried and pulverized at 60 ° C. for 12 hours to obtain 1250 g of an organically modified clay compound.

[Preparation of solid catalyst]
In a 5 L flask, 450 g of organically modified clay compound synthesized according to [Preparation of Modified Clay Compound] was suspended in 1.4 kg of hexane, and 1.78 kg (1.8 mol) of a 20 wt% solution of triisobutylaluminum in hexane, bis ( 7.32 g (18 mmol) of n-butyl-cyclopentadienyl) zirconium dichloride was added, heated to 60 ° C. and stirred for 1 hour. Next, the supernatant was removed, 0.45 kg (0.45 mol) of a 20 wt% solution of triisobutylaluminum in hexane was added, and the mixture was re-diluted with hexane to 4.5 L. To this reaction solution, 0.56 g (0.9 mmol) of diphenylmethylene (cyclopentadienyl-9-fluorenyl) zirconium dichloride was added and stirred overnight at room temperature to obtain a solid catalyst.

[polymerization]
A polymerization vessel having an internal volume of 300 L was continuously supplied with 105 kg / hour of hexane, 30.0 kg / hour of ethylene, 95 NL / hour of hydrogen and the obtained solid catalyst. Moreover, it superposed | polymerized at 85 degreeC of superposition | polymerization temperature, respectively supplying continuously so that the density | concentration of the triisobutyl aluminum in a liquid might be set to 0.93 mmol / kg hexane. The obtained polymer had an MFR of 4.8 g / 10 min. At this time, the strand surface extruded during the measurement of MFR was smooth and exhibited good workability. The obtained high-density polyethylene (A1) has an MFR of 4.8 g / 10 min, a density of 960 kg / m ³ , Mw / Mn = 5.5, (Mz / Mw) − (Mw / Mn) = 1.5, and a half-value width. (Log (MH / ML)) = 1.07, and the molecular weight component having a molecular weight of 1 million g / mol or more was 0.93% by weight. High density polyethylene (A1) was used in Examples 1 and 2.

Example 1
High-density polyethylene (A1) 85% by weight as the ethylene polymer (A), high-pressure low-density polyethylene (B) as the high-pressure low-density polyethylene (B) having an MFR of 8.0 g / 10 min and a density of 920 kg / m ³ (Tosoh Co., Ltd., trade name Petrocene 214) (B1) was blended in an amount of 15% by weight, and melt-kneaded at 180 ° C. with a 50 mm single screw extruder (Placo) to obtain pellets.

  While measuring the swell ratio, density, and MFR of the obtained pellets, extrusion lamination was performed at a resin temperature of 320 ° C. and a thickness of 20 μm using a 25 mm small uniaxial laminator (Placo). The base material was kraft paper, the line speed was 20 m / min, and the air gap was 80 mm. Also, the back side of the coated kraft paper was coated with polyethylene by the same method. The polyethylene thickness on the back surface was 50 μm.

  Using the obtained laminate, thickness unevenness and heat-resistant pinhole property were measured. The results are shown in Table 1. It can be seen that the number of generated pinholes is small, the heat resistance is excellent, and the thickness unevenness is small.

Example 2
Lamination was carried out in the same manner as in Example 1 except that high-pressure low-density polyethylene (trade name Petrocene 212 manufactured by Tosoh Corporation) (B2) having an MFR of 13.0 g / 10 min and a density of 919 kg / m ³ was used. A body was obtained, and thickness unevenness and heat-resistant pinhole property were measured. The results are shown in Table 1. It can be seen that the number of generated pinholes is small, the heat resistance is excellent, and the thickness unevenness is small.

Comparative Example 1
A laminated body was obtained in the same manner as in Example 1 except that high-density polyethylene (A2) (Nipolon Hard # 5110 manufactured by Tosoh Corporation) was used instead of high-density polyethylene (A1). It was measured. MFR of (A2) is 0.9 g / 10 min, density is 961 kg / m ³ , Mw / Mn = 7.8, (Mz / Mw) − (Mw / Mn) = 1.7, half width (Log (MH /ML))=1.3, the molecular weight component having a molecular weight of 1 million g / mol or more is 1.5% by weight. The results are shown in Table 1. It can be seen that the thickness unevenness is large although the number of generated pinholes is small.

Comparative Example 2
Although the high pressure process low density polyethylene (B1) was not mixed and the extrusion lamination process was tried only with the high density polyethylene (A1), the film forming property was poor and a laminate could not be obtained.

Comparative Example 3
Without mixing the high-density polyethylene (A1), extrusion lamination was performed only with the high-pressure method low-density polyethylene (B1) to obtain a laminate. The results are shown in Table 1, but it can be seen that the number of generated pinholes is too large although the thickness unevenness is small.

Comparative Example 4
Without mixing the high density polyethylene (A1), extrusion lamination was performed only with the high pressure method low density polyethylene (B2) to obtain a laminate. The results are shown in Table 1, but it can be seen that the number of generated pinholes is too large although the thickness unevenness is small.

Claims (3)

1 to 99% by weight of an ethylene homopolymer that satisfies the following requirements (1) to (6), or an ethylene / α-olefin copolymer (A) composed of ethylene and an α-olefin having 3 to 20 carbon atoms; An extruded laminate having at least one polyethylene-based resin composition comprising 99 to 1% by weight of low-density polyethylene (B) obtained by a high-pressure radical polymerization method that satisfies (7) and (8).
(1) Density is 900-975 kg / m ³
(2) Melt mass flow rate of 0.01 to 100 g / 10 min (3) Mw / Mn determined by gel permeation chromatography (GPC) measurement is 3.0 or more (4) Gel permeation chromatography (MPC) satisfying the relationship of (Mz / Mw) − (Mw / Mn) ≧ 0.5 determined by measurement (5) Molecular weight 1 million g from the molecular weight pattern obtained by gel permeation chromatography (GPC) measurement / Molecular molecular weight component is 0.1 to 5.0% by weight of the total weight of the polymer
(6) The molecular weight pattern obtained by gel permeation chromatography (GPC) measurement satisfies the relationship of half width (Log (MH / ML)) <1.1. (7) Density is 910 to 930 kg / m ³
(8) Melt mass flow rate is 0.1 to 100 g / 10 min An ethylene homopolymer, or an ethylene / α-olefin copolymer (A) composed of ethylene and an α-olefin having 3 to 20 carbon atoms (A) 1 to 99% by weight and low density polyethylene (B) 99 to 1% by weight The extruded laminate according to claim 1, wherein the polyethylene resin composition satisfies the following (9) to (11).
(9) Density is 950-975 kg / m ³
(10) Swell measured at a melt mass flow rate of 1 to 100 g / 10 min (11) 160 ° C., die L / D = 8 / 2.095 (mm), cylinder diameter 9.55 mm, piston lowering speed 10 mm / min Ratio is 1.2 or more and 3.0 or less A heat-resistant container, a gas barrier container, a release tape and release paper, a photographic paper support, and a moisture-proof wrapping paper comprising the extruded laminate laminate according to claim 1.