JP5124419B2 - Polyethylene container - Google Patents

Description

  The present invention relates to a polyethylene container, and more specifically, is molded using a composition in which an organically layered silicate is dispersed in a polar group-containing polyethylene, and has excellent gas barrier properties, moldability, and impact resistance. The present invention relates to a polyethylene container that is excellent in DuPont weight drop resistance and can be widely used in various container fields. Furthermore, the present invention relates to a cup-shaped container, particularly a cup-shaped container having gas barrier properties that are not adversely affected by oxygen in the air.

Various containers have been proposed that are integrally molded by injection molding of synthetic resin, such as drink containers for milk beverages and beer, dry food containers, and dessert food containers such as cut fruits and fruit jelly. Has been. Such a container is required to have sufficient gas barrier properties that are not adversely affected by oxygen in the air or the like depending on the drink or food to be stored.
Conventionally, in the field of polyolefin resins, in order to improve gas barrier properties, molded products in which barrier resins are laminated on polyolefin resins, molded products in which barrier resins are dispersed in polyolefin resins, and the like have been widely used. .
On the other hand, many attempts have been made in the past to improve physical properties such as gas barrier properties by dispersing a layered inorganic compound such as layered silicate in a polyolefin resin. (For example, see Patent Documents 1 to 10)
However, it is generally known that impact resistance decreases when a layered inorganic compound is dispersed in a polyolefin resin to impart gas barrier properties. Among the impact resistances, the impact strength by the DuPont weight drop test cannot be improved by simply increasing the rigidity of the molded product, unlike the Izod impact strength. This is presumed to be because the impact resistance depends on how the Izod impact strength can accept the energy until micro-deformation occurs in the material. Therefore, in the Izod impact resistance, it is important to improve the rigidity by using a layered inorganic compound and further finely disperse the layered inorganic compound so that the energy of impact is not concentrated.
On the other hand, the impact strength by the DuPont weight drop resistance test is to disperse as much energy as possible from the minute deformation of the sample to the defect, so in addition to the improvement of Izod impact strength, the sample The flexibility with respect to the deformation and the shock absorption of the base resin are important. Therefore, even if the Izod impact strength is improved, the DuPont weight drop resistance is not necessarily improved. (For example, see Patent Document 11)
In an actual container, not only breakage starting from the notch shape as in the Izod impact test, but also a strong impact is applied from the outside to the point where there is no defect, deformation occurs and the point is the starting point and breakage occurs There are also many.
In general, a material in which a layered inorganic compound is dispersed in a polyolefin resin has an increased viscosity and is inferior in moldability, and finds a material that is excellent not only in gas barrier properties but also in impact resistance and moldability. Is not easy.

Hereinafter, specifically explaining the prior art as an example, Patent Document 1 mainly includes a composition comprising 50 to 99.9% by weight of a polyolefin resin and 0.1 to 50% by weight of a layered silicate, Gas barrier resin molding in which a specific relational expression is established between the oxygen permeability coefficient of the molded body and the oxygen permeability coefficient of the polyolefin resin that is the main component of the composition constituting the molded body and the volume fraction of the layered silicate The body has been proposed.
However, in this case, the effect of improving the gas barrier property is not always satisfactory, and a molded product suitable for various properties such as moldability, molded product appearance, and mechanical strength cannot be obtained.

  Patent Document 2 discloses a polyolefin resin composite material comprising 100 parts by weight of polyolefin resin and 0.1 to 50 parts by weight of organic layered silicate, wherein the organic layered silicate is included in the crystal structure. It is an organized layered silicate in which metal ions contained as exchangeable cations are ion-exchanged with a cationic surfactant, and the hydroxyl group on the crystal side of the organized layered silicate is chemically bonded or chemically bonded to the hydroxyl group. A polyolefin-based resin composite material that has been chemically modified with a chemical substance having an affinity functional group at the end of the molecule has been proposed.

  Patent Document 3 discloses that in a polyolefin resin composite material comprising 100 parts by weight of a polyolefin resin and 0.1 to 50 parts by weight of an organic layered silicate, the organic layered silicate is exchangeable in the crystal structure. An organic layered silicate in which metal ions contained as cations are ion-exchanged with a cationic surfactant, and the crystal side surface of the organic layered silicate is chemically modified with a compound having an anionic surface active ability A polyolefin-based resin composite material has been proposed.

Patent Document 4 discloses a resin composition containing 100 parts by weight of a resin and 0.1 to 20 parts by weight of a layered silicate, wherein the layered silicate includes at least some single layers of layered crystals. There has been proposed a resin composition in which the centers of single-layer surfaces are shifted and overlapped, and are apparently dispersed in the form of a flat plate having a thickness of 5 to 50 nm and a length of 500 nm or more.
However, in the case of these materials, although a gas barrier property improving effect is exhibited to some extent, a molded product that is satisfactory in terms of various properties such as moldability, appearance of the molded product, and mechanical strength is not necessarily obtained.

Patent Document 5 discloses that an olefin polymer, a layered inorganic compound organically formed by an organic cation containing a polar functional group in the molecule, and compatibility with the olefin polymer have a polar functional group. An olefin polymer composed of a polar polymer in a molecule, wherein an interlayer distance of the organically layered inorganic compound in the composition is 20 angstroms or more is proposed. Yes.
However, in this case as well, although a gas barrier property improving effect is exhibited to some extent, it is not always possible to obtain a molded product that satisfies various properties such as moldability, appearance of the molded product, and mechanical strength.

Further, Patent Document 6 discloses a composition obtained by mixing a layered silicate in which an organic substance is intercalated between layers and a modified olefin polymer having a polar group in a side chain. A modified olefin polymer composition characterized by not having a peak corresponding to the interval between the bottom surfaces of the layered silicate on the diffraction spectrum has been proposed.
However, in this case, although an improvement effect is disclosed for improving the dispersibility, a molded product that is satisfactory for various properties such as gas barrier properties and moldability is not always obtained. In addition, when actually used as a product, sufficient impact strength may not be maintained.

On the other hand, Patent Document 7 proposes a clay composite material and a production method in which a layered clay mineral is uniformly and well dispersed in an olefin resin.
However, although this technique is effective with a polypropylene matrix, such an effect cannot always be sufficiently achieved with a polyethylene resin. In addition, when the filler interlayer distance is sufficiently wide, mechanical properties, particularly impact strength, may be significantly reduced depending on the rigidity and molecular weight of the matrix resin.

Patent Document 8 discloses that a layered silicate compound has high mechanical strength, heat resistance, etc. by simply mixing and melt-mixing without solvent without swelling / cleavage with a swelling / dispersing solvent such as an organic solvent. A polyolefin-based composite material that exhibits the above has been proposed.
However, although this technique is effective with a polypropylene matrix, such an effect cannot always be sufficiently achieved with a polyethylene resin. Further, the bending elastic modulus is not necessarily greatly improved, and at the same time, the gas barrier property is not necessarily improved even if the bending elastic modulus is improved.

Patent Document 9 proposes a method for producing a layered silicate composite material in which the rigidity and heat resistance of a polyolefin-based resin are improved and the molding processability is improved, and a molded body made of the composite material.
However, although this technique is effective with a polypropylene matrix, such an effect cannot always be sufficiently achieved with a polyethylene resin. Further, gas barrier properties and impact strength are not necessarily improved even if the flexural modulus is improved.

Patent Document 10 proposes a resin composition including a polypropylene resin, a modified polypropylene resin, and a layered silicate compound, which are excellent in rigidity, impact resistance and dimensional stability and have a good appearance of a molded product.
However, in this case, there is a problem that the mechanical strength at low temperature, particularly the impact strength, is remarkably lowered, and the gas barrier property is not necessarily improved even if the bending elastic modulus is improved.
Patent Document 11 proposes a polyolefin resin composition containing a polyolefin resin composition and an intercalation compound, which does not impair surface properties and is excellent in mechanical properties and deflection temperature under load. .
However, in this case as well, although effective with a polypropylene-based matrix, a polyethylene-based resin does not always exhibit such an effect sufficiently. Further, the bending elastic modulus does not necessarily have a large improvement effect, and the gas barrier property does not necessarily improve even if the bending elastic modulus is improved.

On the other hand, Patent Document 12 discloses a thermoplastic resin obtained by in-mold labeling using a side label and a bottom label for a cup-shaped container, particularly a cup-shaped container having a gas barrier property that is not adversely affected by oxygen in the air. An injection-molded container, wherein each label has at least a barrier layer made of a metal foil layer or a thermoplastic resin layer, and the layer laminated on the container body side has the same material as the container body or adhesiveness with the container body. An in-mold label container is disclosed that is composed of a material having the same.
However, in this container, the in-mold label has a barrier layer, and the barrier property is not necessarily sufficient, and the impact resistance strength is not necessarily sufficient.
Under such circumstances, while improving the conventional problems, in addition to improving gas barrier properties, moldability, appearance of molded products and mechanical strength, early development of polyethylene containers that can satisfy various characteristics such as productivity It has been demanded.

Japanese Patent Laid-Open No. 10-298358 JP 2000-355640 A JP 2001-064454 A JP 2003-105200 A JP 2004-091775 A JP 2006-131896 A Japanese Patent Laid-Open No. 10-182892 Japanese Patent Laid-Open No. 10-030039 JP 2000-281841 A JP 2002-037940 A JP 2000-159941 A JP 08-132477 A

  In view of the above-mentioned problems of the prior art, the object of the present invention is not only an effect of improving gas barrier properties, but also polyethylene having excellent properties such as productivity in addition to improvement of moldability, appearance of molded products, and mechanical strength. Polyethylene container that is excellent in gas barrier properties, particularly oxygen permeation prevention, can be easily molded, has good appearance of molded products, has improved rigidity, impact resistance, etc., and has very high production efficiency Providing containers, and further providing gas barrier cup-shaped containers suitable for drink containers such as milk drinks and beer, dry food containers, and dessert food containers such as cut fruits and fruit jelly It is in.

  As a result of intensive studies in order to solve the above problems, the present inventors have obtained a specific viscosity characteristic obtained by blending a polar group-containing polyethylene having specific physical properties with an organic layered silicate in a specific ratio. It has been found that a polyethylene-based container that can solve these problems can be produced by using the molding material having the present invention, and the present invention has been completed.

That is, according to the first invention of the present invention, the organic layered silicate (A) is 5 to 30% by weight, the density is 0.920 to 0.940 g / cm ³ , the temperature is 190 ° C., and the load is 2.16 kg. The melt flow rate (MFR) measured is 70 to 95% by weight of the polar group-containing polyethylene (B) having a melt flow rate (MFR) of 1 to 30 g / 10 minutes, and satisfies the following characteristics (1) to (4): A polyethylene-based container is provided.
Characteristic (1): Viscosity η ₄₈ (Pa · s) measured at a temperature of 190 ° C. and a shear rate of ₄₈ sec ⁻¹ with a capillary rheometer and a viscosity η ₃₁₀₀ (Pa · s) measured at a shear rate of ₃₁₀₀ sec ⁻¹ The ratio (η ₄₈ / η ₃₁₀₀ ) is 7-30.
Characteristic (2): Oxygen permeability coefficient P (cm ³ · mm / m ² · 24 hr · atm) (23 ° C. · 65% RH) of polyethylene container and polar group-containing polyethylene (B oxygen permeability coefficient _{^{P 0 (cm 3 · mm /}} m 2 · 24hr · atm) the ratio P / _{P 0} of (23 ℃ · 65% RH) of) is 0.7 or less.
Characteristic (3): The flexural modulus is 900 MPa or more.
Characteristic (4): 50% fracture energy (E ₅₀ ) of DuPont weight resistance to fall is 110 to 300 kgf · cm at 23 ° C. and 100 to 250 kgf · cm at −30 ° C.

  According to the second invention of the present invention, there is provided a polyethylene container according to the first invention, wherein the layered silicate used in the organically modified layered silicate (A) is montmorillonite and / or mica.

  According to the third invention of the present invention, in the first or second invention, the polar group-containing polyethylene (B) contains 0.1 to 5.0% by weight of an unsaturated carboxylic acid and / or a derivative thereof. A system container is provided.

According to the fourth invention of the present invention, in the first to third inventions, there is provided a polyethylene container molded by injection molding.
Furthermore, according to the fifth aspect of the present invention, there is provided a polyethylene container according to the first to fourth aspects, wherein the container is a cup.

According to the present invention, a polyethylene container having not only excellent gas barrier properties, particularly oxygen permeation prevention properties, but also excellent properties such as moldability, appearance of molded products, mechanical strength, heat resistance and the like, in addition to excellent impact resistance. Since it can be obtained and can be used in a wide range of fields including various container fields due to its characteristics, the industrial utility is very high.
In particular, not only the Izod impact strength but also the impact resistance strength by the DuPont weight drop test can be improved, and a gas barrier cup-shaped container excellent in oxygen permeation prevention can be produced.

The polyethylene container of the present invention has an organic layered silicate (A) (hereinafter sometimes simply referred to as “component (A)”) in an amount of 5 to 30% by weight and a density of 0.920 to 0.940 g. Polar group-containing polyethylene (B) having a melt flow rate (MFR) of 1 to 30 g / 10 min measured at / cm ³ , a temperature of 190 ° C. and a load of 2.16 kg (hereinafter simply referred to as “component (B)”) (It may be abbreviated.) 70 to 95% by weight.
Hereinafter, the (A) component, the (B) component and other optional components used in the polyethylene container of the present invention, and the molding method of the container and its characteristics will be described in detail for each item.

1. Organized layered silicate (A)
The organically modified layered silicate (A) constituting the polyethylene container of the present invention is obtained by organicizing a layered silicate.
The layered silicate is a conventionally known silicate mineral having an exchangeable cation between layers, and usually flaky crystals having a thickness of about 1 nm and an average aspect ratio of about 20 to 200 are aggregated by ionic bonds. Specifically, for example, smectite group such as montmorillonite, beidellite, nontronite, saponite, hectorite, saconite, vermiculite group such as vermiculite, mica group such as muscovite, phlogopite, teniolite, Examples include kaolinites such as kaolinite, daikanite, nacrite, and hyrosite, chlorite such as clinochlore, chamosite, nimitite, sudite, kukeite, and donbasite, and phyllosilicate minerals such as apophyllite, talc, and mica. . These layered silicates may be used alone or in combination of two or more.
Among these layered silicates, montmorillonite and / or mica are preferable because they have a large effect of improving gas barrier properties and dispersibility.

In the present invention, the organic layered silicate (A) is an organic material intercalated between the layers of the layered silicate, and the organic material is particularly limited as long as it has a dipole moment. Although not intended, organic onium salts such as organic ammonium salts, organic phosphonium salts, and organic sulfonium salts are preferred. Among them, an organic onium salt having an alkyl chain having 8 or more carbon atoms is preferable because the interlayer of the layered silicate can be sufficiently nonpolar or low in polarity, and among them, an ammonium salt and a phosphonium salt are more preferable, and an ammonium salt Is particularly preferred. Specific examples of the ammonium salt include trioctyl ammonium salt, lauryl trimethyl ammonium salt, stearyl ammonium salt, stearyl trimethyl ammonium salt, distearyl dimethyl ammonium salt, and distearyl dibenzyl ammonium salt.
Specific compounds include methyl, tallow, bis (2-hydroxyethyl) ammonium chloride, dimethyl, benzyl, hydrogenated tallow ammonium chloride, dimethyl, hydrogenated tallow, 2-ethylhexylammonium chloride, methyl dihydrogenated tallow ammonium. Preferred examples include chloride, dimethyl / dihydrogenated tallow ammonium chloride, trioctylmethyl ammonium chloride, alkyl bis (2-hydroxyethyl) ammonium chloride, polyoxypropylene methyl diethyl ammonium chloride and the like.

  The proportion of the organic substance that the layered silicate has between the layers is preferably 20 to 70% by weight, and particularly preferably 25 to 40% by weight. If the ratio of the organic substance is less than the above range, it tends to be difficult to make the layer of the layered silicate sufficiently non-polar or low-polarity, while if it exceeds the above range, the organic substance is intercalated in the layered silicate. Since the ratio of the layered silicate to the amount used decreases, the initial purpose of the layered silicate tends not to be sufficiently expressed.

  In the present invention, as the organically modified layered silicate (A), a commercially available layered silicate having an organic substance intercalated between layers can be used, or a layered form in which the organic substance is not intercalated. It is also possible to use a layered silicate prepared by intercalating the organic material between layers by adding the organic material to the silicate and performing ion exchange.

2. Polar group-containing polyethylene (B)
In the polyethylene container of the present invention, the polar group-containing polyethylene (B) is a polymer obtained by graft-reacting an ethylenically unsaturated monomer having a polar group to an ethylene polymer not containing a polar group as a precursor. And a polymer obtained by copolymerizing an ethylenically unsaturated monomer having a polar group at the time of polymerization of ethylene, or a polymer obtained by blending an ethylene polymer not containing a polar group.
A preferred ratio of blending an ethylene polymer not containing a polar group is a polymer obtained by graft-reacting an ethylenically unsaturated monomer having a polar group to an ethylene polymer not containing a polar group as a precursor, or It is 0 to 95% by weight with respect to 100 to 5% by weight of the polymer copolymerized by coexisting an ethylenically unsaturated monomer having a polar group during the polymerization of ethylene.
Specific examples of the ethylene polymer as a precursor of the polar group-containing polyethylene include, for example, ethylene homopolymer, ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, Carbon number 2 such as 4-methyl-1-pentene, 4,4-dimethyl-1-pentene, 1-hexene, 4-methyl-1-hexene, 1-heptene, 1-octene, 1-decene, 1-octadecene A binary or ternary copolymer with about 18 to other α-olefins, specifically, for example, ethylene homopolymers such as branched low-density polyethylene and linear high-density polyethylene, ethylene -Propylene copolymer, ethylene-1-butene copolymer, ethylene-propylene-1-butene copolymer, ethylene-4-methyl-1-pentene copolymer, ethylene-1-he Sen copolymers, ethylene-heptene copolymers, include ethylene-based resin of an ethylene-1-octene copolymers, these ethylene polymers are more than two may be used together.
Moreover, when it aims at modification | reformation, the copolymerization with diene is also possible. Examples of the diene compound used at this time include butadiene, 1,4-hexadiene, ethylidene norbornene, dicyclopentadiene, and the like. The comonomer content during the polymerization can be arbitrarily selected. For example, in the case of copolymerization of ethylene and an α-olefin having 3 to 12 carbon atoms, an ethylene / α-olefin copolymer is used. The α-olefin content therein is 0 to 40 mol%, preferably 0 to 30 mol%.

  These ethylene polymers preferably have a weight average molecular weight of 2,000 to 500,000, more preferably 5,000 to 200,000, and 10,000 to 100,000. Is particularly preferred.

As the polymerization catalyst for the ethylene polymer, various catalysts such as a Ziegler catalyst, a Phillips catalyst, and a metallocene catalyst are used. Any polymerization catalyst can be used as long as hydrogen exhibits a chain transfer action of olefin polymerization.
Specifically, any catalyst that is composed of a solid catalyst component and an organometallic compound and that is suitable for slurry-based olefin polymerization such that hydrogen exhibits a chain transfer action of olefin polymerization can be used. Preferred is a heterogeneous catalyst in which polymerization active sites are localized.
The solid catalyst component is not particularly limited as long as it is used as a solid catalyst for olefin polymerization containing a transition metal compound. As the transition metal compound, compounds of elements of Group 4 to Group 10 of the periodic table, preferably Group 4 to Group 6, can be used, and specific examples include Ti, Zr, Hf, V, Cr. And compounds such as Mo.

The metallocene catalyst that can be used as a polymerization catalyst for the ethylene-based polymer is a type of catalyst called a so-called single site catalyst having a relatively single active site. Metallocene complexes, for example, a catalyst obtained by reacting zirconium or titanium biscyclopentadienyl complex with methylaluminoxane as a co-catalyst, and homogeneous or non-uniform combinations of various complexes, co-catalysts, supports, etc. It is a homogeneous catalyst.
Examples of the metallocene catalyst include JP-A-58-19309, 59-95292, 59-23011, 60-35006, 60-35007, 60-35008, and 60-35009. No. 61-130314 and JP-A-3-163088, and the like.

The polyethylene can be produced by a production process such as a gas phase polymerization method, a solution polymerization method, or a slurry polymerization method. Among the polymerization conditions of the ethylene polymer, the polymerization temperature can be selected from the range of 0 to 300 ° C. The polymerization pressure can be selected from the range of atmospheric pressure to about 100 kg / cm ² . It is selected from aliphatic hydrocarbons such as hexane and heptane, aromatic hydrocarbons such as benzene, toluene and xylene, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, etc. in a state where oxygen and water are substantially cut off. It can be produced by polymerizing ethylene and α-olefin in the presence of an inert hydrocarbon solvent.

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

  In order to make the ethylene polymer into a polar group-containing polyethylene, a method of grafting an ethylenically unsaturated monomer having a polar group to the ethylene polymer, and a polar group at the time of polymerization of the ethylene polymer Conventional methods such as a method of copolymerization in the presence of an ethylenically unsaturated monomer having a polar group can be employed, but a method of grafting an ethylenically unsaturated monomer having a polar group to an ethylene polymer is particularly preferable.

As the ethylenically unsaturated monomer, specifically, for example, as the ethylenically unsaturated monomer having a carboxyl group, (meth) acrylic acid [herein, “(meth) acryl” is , “Acrylic” or / and “methacrylic”. ], Crotonic acid, isocrotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, etc., and ethylenically unsaturated monomers having a carboxylic acid anhydride group include maleic anhydride, itaconic anhydride, anhydrous Citraconic acid and the like, and ethylenically unsaturated monomers having a carboxylic acid ester group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, As the ethylenically unsaturated monomer having a hydroxyl group, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2,3-dihydroxypropyl (meth) acrylate, 2-hydroxymethyl-3- Hydroxypropyl (meth) acrylate, 2,2-dihydroxymethyl-3- Droxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and the like, and as an ethylenically unsaturated monomer having an epoxy group, glycidyl (meth) acrylate, Propyl glycidyl maleate, butyl glycidyl maleate, propyl glycidyl fumarate, butyl glycidyl fumarate, etc., and ethylenically unsaturated monomers having an amide group include (meth) acrylamide, etc. Examples of the ethylenically unsaturated monomer include (meth) acrylonitrile, and examples of the ethylenically unsaturated monomer having an amino group include aminoethyl (meth) acrylate, and ethylene having an imide group. Examples of the unsaturated monomer include maleic imide and the like, Examples of the ethylenically unsaturated monomer having a socyanate group include 2-isocyanatoethyl (meth) acrylate, (meth) acryloyl isocyanate, vinyl isocyanate, isopropenyl isocyanate and the like, and an ethylenically unsaturated monomer having an acetyl group Examples of the body include vinyl acetate and the like, and the thiol group, ether group, thioether group, sulfone group, phosphone group, nitro group, urethane group, halogen atom and the like as polar groups are known methods. It can be modified by adding directly to the main chain of the olefin polymer.
Among these, unsaturated carboxylic acid and / or its derivative are preferable, and maleic anhydride and / or its anhydride are particularly preferable from the viewpoint of dispersibility of the layered silicate.

  The graft reaction of the ethylenically unsaturated monomer having a polar group is, for example, a melt grafting method performed in a molten state of an ethylene polymer in the presence of a radical generator, and a solution performed in a solution state using an organic solvent. Any of the conventional grafting methods may be used, but the melt grafting method is preferred because it can be produced without using a solvent.

  In this case, specific examples of the radical generator used include di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di ( Dialkyl peroxides such as t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, 1,3-bis (t-butylperoxyisopropyl) benzene T-butylperoxyacetate, t-butylperoxy-2-ethylhexanoate, t-butylperoxypivalate, t-butylperoxybenzoate, t-butylperoxyisopropylcarbonate, 2,5-dimethyl- 2,5-di (benzoylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) ) Peroxyesters such as hexyne-3, diacyl peroxides such as 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, benzoyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, Organic peroxides such as hydroperoxides such as diisopropylbenzene hydroperoxide and 2,5-dimethyl-2,5-di (hydroperoxy) hexane, and ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide Or 2,2′-azobisisobutyronitrile, 2,2′-azobis (isobutyramide) dihalide, 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], Azodi-t-butane, etc. Azo compounds, and the like.

  In the melt grafting method, the ethylene-based weight is used by using a kneader such as a uniaxial or biaxial extruder, a horizontal biaxial agitator such as a horizontal biaxial multi-disc apparatus, a vertical agitator such as a double helical ribbon agitator, or the like. The ethylenically unsaturated monomer is usually 0.005 to 20 parts by weight, preferably 0.1 to 5 parts by weight, and the radical generator is usually used with respect to 100 parts by weight of the polymer and the ethylene polymer. 0.001 to 10 parts by weight, preferably 0.01 to 5 parts by weight, is usually about 100 to 300 ° C., preferably about 100 to 200 ° C. .The grafting reaction is carried out for about 5 to 10 minutes.

The density of the polar group-containing polyethylene of the present invention is measured according to JIS K6922-1 and 2: 1997, and is 0.920 to 0.940 g / cm ³ , preferably 0.920 to 0.935 g / cm ³ , more preferably 0.920 to 0.930 g / cm ³ . When the density is less than 0.920 g / cm ³ , the rigidity of the molded body tends to decrease, and when it exceeds 0.940 g / cm ³ , the durability of the molded body tends to decrease.
The density of the polar group-containing polyethylene can be controlled by adjusting the density of the ethylene polymer that is the main component of the polar group-containing polyethylene. The density of the ethylene polymer is a comonomer that is copolymerized with ethylene. The desired product can be obtained by changing the type and amount.

The melt flow rate (MFR) measured at a temperature of 190 ° C. and a load of 2.16 kg of the polar group-containing polyethylene of the present invention is measured according to JIS K6922-2: 1997, and is 1 to 30 g / 10 minutes, preferably 2 to 15 g / 10 minutes, more preferably 3 to 10 g / 10 minutes. If the MFR is less than 1 g / 10 minutes, the fluidity of the molding material is lowered and the moldability is inferior, and if it exceeds 30 g / 10 minutes, the impact resistance of the molded article is lowered.
The MFR of the polar group-containing polyethylene can be controlled by adjusting the MFR of the ethylene polymer that is the main component of the polar group-containing polyethylene. The MFR of the ethylene polymer can be controlled by the ethylene polymerization temperature or chain transfer. It can be adjusted by the use of the agent and the desired product can be obtained. That is, by increasing the polymerization temperature of ethylene and α-olefin, the molecular weight can be decreased, and as a result, the MFR can be increased. By decreasing the polymerization temperature, the molecular weight can be increased, and as a result, the MFR can be decreased. . In addition, the molecular weight can be lowered by increasing the amount of hydrogen coexisting in the copolymerization reaction of ethylene and α-olefin (chain transfer agent amount), resulting in an increase in MFR, and the amount of hydrogen coexisting (chain transfer). The molecular weight can be increased by decreasing the (drug amount), and as a result, the MFR can be reduced.

3. Blending ratio of organic layered silicate (A) and polar group-containing polyethylene (B) In the polyethylene container of the present invention, a polyethylene container comprising organic layered silicate (A) and polar group-containing polyethylene (B). The ratio of these two components is 5 to 30% by weight of the organic layered silicate (A), 70 to 95% by weight of the polar group-containing polyethylene (B), preferably 8 to 20 of the organic layered silicate (A). % By weight and the polar group-containing polyethylene (B) is 80 to 92% by weight.
When the organic layered silicate (A) is less than 5% by weight (when the polar group-containing polyethylene (B) exceeds 95% by weight), the gas barrier property is lowered, and the fluidity is lowered, resulting in poor moldability. When the organically modified layered silicate (A) exceeds 30% by weight (if the polar group-containing polyethylene (B) is less than 70% by weight), the fluidity decreases and a good molded product cannot be obtained. Impact strength is significantly reduced.

4). Characteristics of polyethylene container, etc. The polyethylene container of the present invention must satisfy the following characteristics (1) to (4). The technical significance of each characteristic will be described below.
(1) Characteristics (1) (Viscosity ratio)
Polyethylene container of the present invention, a cylinder temperature of 190 ° C. at a capillary rheometer, 1 mm in diameter with a length 30mmL / D = 30 inflow angle 90 degrees of the capillary, viscosity eta ₄₈ measured at a shear rate of 48sec ^-1 (Pa It is important that the ratio (η ₄₈ / η ₃₁₀₀ ) of the viscosity η ₃₁₀₀ (Pa · s) measured at a shear rate of ₃₁₀₀ sec ⁻¹ is 7 to 30, preferably 10 to 20. When the ratio (η ₄₈ / η ₃₁₀₀ ) is less than 7, high-speed moldability is inferior at the time of molding or recycle molding, and when it exceeds 30, the physical properties are remarkably lowered. In order to increase the ratio, the molecular weight distribution of the ethylene polymer may be expanded or the amount of layered silicate added may be increased. In order to broaden the molecular weight distribution of ethylene polymers, it is achieved by mixing components with different molecular weights or performing multi-stage polymerization, or polymerizing using a catalyst that can broaden the molecular weight distribution (Ziegler catalyst, preferably Philips catalyst). I can do it.

(2) Characteristics (2) (Oxygen permeability coefficient)
The polyethylene container of the present invention has an oxygen permeability coefficient P (cm ³ · mm / m ² · 24 hr · atm) (23 ° C. · 65% RH) measured using a 1 mmt injection molded test piece, and a polyethylene container Oxygen permeability coefficient P ₀ (cm ³ · mm / m ² · 24 hr · atm) (23 ° C. · 65% RH) of the polar group-containing polyethylene (B) which is the main component of P / P ₀ is 0.7 or less Preferably, it is 0.5 or less because of excellent gas barrier properties. To reduce the P / P _0, increase the amount of the layered silicate, the aspect ratio of the layered silicate alone (average thickness and the average length ratio of the layered silicate particles: length / thickness) is greater that Can be achieved.

(3) Characteristics (3) (Bending elastic modulus)
The polyethylene container of the present invention has a flexural modulus of 900 MPa or more, preferably 1000 to 3000 MPa, and more preferably 1000 to 2000 MPa. The bending elastic modulus is 10 × 80 × 4 mm test piece formed by injection molding at 210 ° C. with a JIS K-7152-1: 1999 type A mold, and conforms to JIS K6922-2: 2005. Measured.
If the flexural modulus is less than 900 MPa, the rigidity tends to be insufficient when the polyethylene container is made thin. The flexural modulus can be adjusted by changing the density of the polar group-containing polyethylene or changing the content / type of the organically modified layered silicate.

(4) Characteristics (4) (DuPont weight drop resistance)
The polyethylene container of the present invention has a DuPont weight drop resistance 50% fracture energy (E ₅₀ ) of 110 kgf · cm or more, preferably 120 to 300 kgf · cm, more preferably measured using a 2 mmt injection molded test piece. Is 120 to 150 kgf · cm.
When the 50% fracture energy of the DuPont type weight drop resistance is less than 110 kgf · cm, when used as a container, if an impact perpendicular to the surface is applied, damage is likely to occur, resulting in poor practicality. Moreover, when larger than 300 kgf * cm, fluidity | liquidity falls and a defect may arise in a moldability and a product external appearance.
DuPont weight drop resistance reduces the density of the polar group-containing polyethylene as the base material, and further disperses the organically modified layered silicate at the nanoscale so that it can be incorporated into the entanglement of the molecular chains of the base material (crystallization It is greatly improved by lowering the degree). The mechanism is that the impact received instantaneously is received by the layered silicate, and then the impact force is absorbed by the continuous yield at the base material to prevent the progress of fracture. Therefore, the density of the polar group-containing polyethylene as a base material is an important factor. In addition, some adjustments can be made by changing the molecular weight distribution / composition distribution of the substrate and the content / type of the organically modified layered silicate.
Since the container of the present invention is excellent in DuPont impact strength, it is suitable as a gas barrier cup-shaped container excellent in oxygen permeation prevention, such as a cup or an in-mold cup.

5. About optional components The above polyethylene-based container is formed into various molded articles after pelletizing the organically modified layered silicate (A) and the polar group-containing polyethylene (B) by mechanical melt mixing with a pelletizer or homogenizer according to a conventional method. The desired container can be formed by molding with a machine.
At that time, in addition to other olefinic polymers and rubbers, the above-mentioned materials include, in addition to antioxidants, ultraviolet absorbers, light stabilizers, lubricants, antistatic agents, antifogging agents, and antiblocking agents, in accordance with conventional methods. , Processing aids, coloring pigments, pearl pigments, glittering materials, polarizing pearl pigments, crosslinking agents, foaming agents, neutralizing agents, thermal stabilizers, crystal nucleating agents, inorganic or organic fillers, flame retardants and other known additives Can be blended. As a coloring method, a compound added in a necessary amount to the base resin or a master batch added at a high concentration may be post-blended.

  As additives, for example, antioxidants (phenolic, phosphorus-based, sulfur-based), lubricants, antistatic agents, light stabilizers, ultraviolet absorbers, and the like can be appropriately used in combination of one or more. Other fillers include calcium carbonate, talc, metal powder (aluminum, copper, iron, lead, etc.), silica, diatomaceous earth, alumina, gypsum, barium sulfate, carbon nanotubes, graphite, carbon black, titanium oxide, various whiskers, etc. Can be used. In any case, various additives can be blended with the molding material as necessary, and the mixture can be kneaded with a kneading extruder, a Banbury mixer, or the like to obtain a molding material.

  The method for producing the material of the polyethylene container of the present invention is not particularly limited. For example, a method of directly blending and mixing a predetermined amount of polar group-containing polyethylene and layered silicate, a polar compound-containing polyethylene having a predetermined blending amount or more. There is a so-called master batch method in which a layered silicate is blended and mixed to prepare a master batch, and polyethylene that does not contain a polar group is added to the adjusted master batch to dilute it to a predetermined blending amount.

6). Production method of polyethylene container The method for molding the polyethylene container of the present invention is not particularly limited, but injection molding is particularly preferred. It can be formed into a molded body using a normal injection molding machine, and the molding conditions can be appropriately set depending on the size and shape of the molded product to be obtained, but the temperature of the molding material is 160 to 270 ° C., and the injection speed is 20 to 1000 mm. The molding is preferably performed under the conditions of / sec. When an injection molded article is molded using the molding material of the present invention, the layered silicate is almost uniformly dispersed in the polar group-containing polyethylene, but each layer of the layered silicate forms an array structure aligned in one direction, and gas molecules However, the path | pass which passes in matrix resin (polar group containing polyethylene) becomes long, and can exhibit the outstanding gas barrier property effect. In addition, there are some layered silicates that do not form an array structure in which each layer is aligned in one direction, but these layered silicates are also dispersed almost uniformly in the matrix resin, so the mechanical strength of the molded body Etc. can be improved in a well-balanced manner.

  The polyethylene container of the present invention is not only excellent in gas barrier properties, but also excellent in appearance and moldability of molded products, and excellent in impact resistance, in particular, DuPont weight drop resistance, so it can be suitably used as various containers. It is very useful for industry.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples unless it exceeds the gist. The measurement methods and materials used in the examples are as follows.

1. Measuring method (1) Density: Measured according to JIS K6922-1 and 2: 1997.
(2) Melt flow rate (MFR) at a temperature of 190 ° C. and a load of 2.16 kg: measured in accordance with JIS K6922-2: 1997.
(3) Viscosity: Using an INTESCO fully automatic capillary rheometer manufactured by INTESCO, using a capillary with a diameter of 1 mm, a length of 30 mm, and a material incident angle of 90 °, at a set temperature of 190 ° C., a shear rate of 48 sec ⁻¹ , shear The viscosity η (Pa · s) at each shear rate at a speed of 3100 sec ⁻¹ was measured.
(4) Oxygen permeability coefficient of molded article: using Toshiba Machine's injection molding machine IS-150, set temperature 210 ° C., injection speed 50 mm / second, injection holding time 10 seconds, mold temperature 40 ° C., cooling time 20 A sheet having a length of 12 cm, a width of 12 cm, and a thickness of 1 mm was prepared under the conditions of seconds. The oxygen transmission coefficient (cm ³ · mm / m ² · 24 hr · atm) of the sample sheet molded by the above method was measured using MOCON OXTRAN 2/21 under conditions of a humidity of 65% RH and a temperature of 23 ° C.
(5) Flexural modulus: 10 × 80 × 4 mm test piece was formed by injection molding at 210 ° C. using a JIS K-7152-1: 1999 type A mold, and JIS K6922-2: 2005. Measured according to

(6) Charpy impact strength: measured according to JIS K6922-2: 2005.
(7) Spiral flow (210 ° C.): using IS-80 manufactured by Toshiba Machine Co., Ltd., set temperature 210 ° C., injection pressure 75 MPa, injection time 5 seconds, cooling time 10 seconds, holding pressure switching position 7 mm, cushion position 1.9 The longest flow length was measured using a mold having a spiral flow path having a width of 10 mm, a thickness of 2 mm, and a longest flow path length of 2000 mm under conditions of ˜2.1 mm and a mold temperature of 30 ° C.
(8) Molded product surface appearance: The appearance of the injection-molded product is visually evaluated to evaluate its state, and “good” is obtained when there is no unevenness and layered silicate agglomeration is not observed or is close to it. Those with poor dispersion and agglomeration were regarded as “bad”.
(9) DuPont-type weight drop resistance: molded in accordance with JIS K5600-5-3: 1999, under the same conditions as those of the Toyo Seiki SHEET IMPACT TESTER, weight (mass: 2000 g), and injection molded product of (4) above. Measurement was performed at a temperature of 23 ° C. and −30 ° C. using a 2 mm thick sheet (2 mm × 10 mm × 10 mm). The energy at which the plate breaks with a probability of 50% was defined as 50% fracture energy (E ₅₀ ).
E ₅₀ prepares the 10 plates per any height, to determine the highest height no destruction all 10 sheets of (H1) (cm). After determining this height (H1), the height of the 25 mm weight is raised, and it is confirmed that at least one of the plates breaks at that height. Next, determine the lowest height (H2) (cm) at which all 10 samples break, lower the height of the 25 mm weight from H2, and confirm that at least one plate does not break at that height. To do. The difference in height between H1 and H2 is divided into five equal parts to determine the height interval (S) (cm). A drop test was carried out by changing the height from 6 to H2 at every height interval (S) from H1 to confirm how many out of 10 sheets were broken at each height interval, and the ratio of plate destruction (%) Ask for. The total destruction ratios at all six levels are summed, and the sum (T) of the destruction ratios is obtained. E ₅₀ can be calculated by the following equation using the above H2, S, and T.
_{E 50 = {H2-S (} T / 100-1 / 2)} × 2000 (g)

2. Materials The following materials were used as the component (A) and the component (B).
(A) Component: Organized layered silicate (1) Organized montmorillonite SOUTHERN PLAY PRODUCTS, INC. Cloisite (registered trademark) 15A (dimethylditallow ammonium chloride-treated organized montmorillonite, organic matter amount: about 43%)
(2) Organic mica OP Chemical Co. Somashif _MAE (C 14 _{-C 18} dialkyl dimethyl ammonium salts fluorination treatment Mica organic matter:. 37%)
(3) Talc Fuji Talc Kogyo LMS-100

Component (B): Polar group-containing polyethylene (1) Polar group-containing polyethylene having a density of 0.925 g / cm ³ , an MFR of 3 g / 10 min, and an anhydrous maleic acid oxidation rate of 0.48 wt%.
(2) A polar group-containing polyethylene having a density of 0.935 g / cm ³ , an MFR of 10 g / 10 min, and an anhydrous maleic acid oxidation rate of 0.40 wt%.
(3) A polar group-containing polyethylene having a density of 0.938 g / cm ³ , an MFR of 35 g / 10 min, and an anhydrous maleic acid oxidation rate of 0.23% by weight.
(4) A polar group-containing polyethylene having a density of 0.962 g / cm ³ , an MFR of 5 g / 10 min, and an anhydrous maleic acid oxidation rate of 0.23% by weight.
(5) A polar group-containing polyethylene having a density of 0.961 g / cm ³ , an MFR of 34 g / 10 min, and an anhydrous maleic acid oxidation rate of 0.43% by weight.
(6) A polar group-containing polyethylene having a density of 0.962 g / cm ³ , an MFR of 0.5 g / 10 min, and an anhydrous maleic acid oxidation rate of 0.23% by weight.
(7) Polypropylene with a density of 0.912 g / cm ³ and MFR of 11 g / 10 min

[Example 1]
15% by weight of organic mica (Somasif MAE manufactured by Corp Chemical Co.) and 85% by weight of polar group-containing polyethylene (1) are fed into a twin screw extruder TEX30α manufactured by Nippon Steel Works, and melt-kneaded at a set temperature of 210 ° C. The extruded strand was pelletized with a pelletizer. Using the obtained pellets, using an injection molding machine IS-150 manufactured by Toshiba Machine Co., Ltd. under the conditions of a set temperature of 210 ° C., an injection speed of 50 mm / second, an injection time of 10 seconds, a mold temperature of 40 ° C., and a cooling time of 20 seconds. A sheet having a length of 12 cm, a width of 12 cm, and a thickness of 1 mm, and a sheet having a length of 12 cm, a width of 12 cm, and a thickness of 2 mm were prepared. The oxygen permeation coefficient P was measured using a sheet having a thickness of 1 mm, and the Dupont weight drop resistance was measured using a sheet having a thickness of 2 mm.
In addition, a sheet having a polar group-containing polyethylene (1) Similarly 1mm thick only, the oxygen permeation coefficient P ₀ using the obtained sheet was measured. From these was calculated _P / P _0.
Furthermore, the viscosity η (Pa · s) at each shear rate was measured for the pellets obtained as described above. Table 1 shows the results of measuring various physical properties.

[Example 2]
It was carried out in the same manner as in Example 1 except that the blending ratio of organic mica (Somasif MAE manufactured by Corp Chemical Co., Ltd.) was 20% by weight and the blending ratio of the polar group-containing polyethylene (1) was 80% by weight.
Table 1 shows the results of measuring various physical properties.

[Example 3]
The same procedure as in Example 2 was conducted except that organicized montmorillonite (SOUTHERN PLAY PRODUCTS, INC. Cloisite (registered trademark) 15A) was used instead of organic mica (Somasif MAE manufactured by Corp Chemical Co., Ltd.).
Table 1 shows the results of measuring various physical properties.

[Example 4]
It carried out like Example 2 except having used polar group content polyethylene (2) instead of polar group content polyethylene (1).
Table 1 shows the results of measuring various physical properties.

[Example 5]
The same procedure as in Example 4 was conducted except that organicized montmorillonite (SOUTHERN PLAY PRODUCTS, Cloisite (registered trademark) 15A manufactured by INC) was used instead of organic mica (Somasif MAE manufactured by Corp Chemical Co., Ltd.).
Table 1 shows the results of measuring various physical properties.

[Comparative Example 1]
The same procedure as in Example 1 was performed except that organic mica (Somasif MAE manufactured by Corp Chemical Co.) was not used.
Table 1 shows the results of measuring various physical properties. In this example, the gas barrier property of the molded body was low, and the flexural modulus and the DuPont weight drop resistance were also low.

[Comparative Example 2]
It was carried out in the same manner as in Example 1 except that the blending ratio of organic mica (Somasif MAE manufactured by Corp Chemical Co., Ltd.) was 3% by weight and the blending ratio of the polar group-containing polyethylene (1) was 97% by weight.
Table 1 shows the results of measuring various physical properties. In this example, a low increase gas barrier properties P / P ₀ of the molding, also low flexural modulus.

[Comparative Example 3]
The same procedure as in Example 1 was carried out except that the blending ratio of organic mica (Somasif MAE manufactured by Corp Chemical Co., Ltd.) was 35% by weight and the blending ratio of the polar group-containing polyethylene (1) was 65% by weight.
Table 1 shows the results of measuring various physical properties. In this example, the appearance of the molded article was poor and the DuPont weight drop resistance was low.

[Comparative Example 4]
Example 3 except that the blending ratio of organic montmorillonite (SOUTHERN PLAY PROCUTS, INC. Cloisite (registered trademark) 15A) was 35% by weight and the polar group-containing polyethylene (1) was 65% by weight. I did it.
Table 1 shows the results of measuring various physical properties. In this example, the appearance of the molded article was poor and the DuPont weight drop resistance was low.

[Comparative Example 5]
It carried out like Example 1 except having used polar group content polyethylene (3) instead of polar group content polyethylene (1).
Table 1 shows the results of measuring various physical properties. In this example, the DuPont weight drop resistance was low.

[Comparative Example 6]
Using polar group-containing polyethylene (4) instead of polar group-containing polyethylene (1), blending ratio of organic montmorillonite (SOUTHERN RAY PRODUCTS, INC. Cloisite (registered trademark) 15A), containing 10% by weight of polar group The same procedure as in Example 3 was performed except that the blending ratio of polyethylene (4) was 90% by weight.
Table 1 shows the results of measuring various physical properties. In this example, the DuPont weight drop resistance was low.

[Comparative Example 7]
It carried out like Example 1 except having used polar group content polyethylene (4) instead of polar group content polyethylene (1).
Table 1 shows the results of measuring various physical properties. In this example, the DuPont weight drop resistance was low.

[Comparative Example 8]
It carried out like Example 1 except having used polar group content polyethylene (5) instead of polar group content polyethylene (1).
Table 1 shows the results of measuring various physical properties. In this example, the DuPont weight drop resistance was low.

[Comparative Example 9]
The same procedure as in Example 2 was performed except that talc (LMS-100 manufactured by Fuji Talc Industrial Co., Ltd.) was used instead of organic mica (Somasif MAE manufactured by Corp Chemical Co.).
Table 1 shows the results of measuring various physical properties. In this example, the appearance of the molded article is poor, the molded body of the P / P ₀ is increased gas barrier properties are low flexural modulus, also low DuPont resistance weight drop resistance.

[Comparative Example 10]
The same procedure as in Example 1 was carried out except that organic mica (Somasif MAE manufactured by Coop Chemical Co., Ltd.) was not used and polar group-containing polyethylene (4) was used instead of polar group-containing polyethylene (1).
Table 1 shows the results of measuring various physical properties. In this example, the DuPont weight drop resistance was low.

[Comparative Example 11]
It carried out like Example 2 except having used polar group content polyethylene (6) instead of polar group content polyethylene (1).
As a result, since the motor torque of the extruder suddenly increased during kneading, pellets could not be obtained.

[Comparative Example 12]
This was carried out in the same manner as in Example 1 except that organic mica (Somasif MAE manufactured by Co-op Chemical Co., Ltd.) was not used and polypropylene (7) was used instead of the polar group-containing polyethylene (1).
Table 1 shows the results of measuring various physical properties. In this example, the DuPont weight drop resistance at 23 ° C. was low, and the tendency was more remarkable at −30 ° C.

[Example 6]
15% by weight of organic mica (Somasif MAE manufactured by Corp Chemical Co.) and 85% by weight of polar group-containing polyethylene (1) are fed into a twin screw extruder TEX30α manufactured by Nippon Steel Works, and melt-kneaded at a set temperature of 210 ° C. The extruded strand was pelletized with a pelletizer. Using the obtained pellets, using an injection molding machine IS-150 manufactured by Toshiba Machine Co., Ltd. under the conditions of a set temperature of 210 ° C., an injection speed of 50 mm / second, an injection time of 10 seconds, a mold temperature of 45 ° C., and a cooling time of 20 seconds. A cup having an inner volume of about 250 ml was prepared using a cup mold having an inner diameter of the upper opening of 63 mm, a diameter of the bottom surface of 51 mm, a height of 104 mm, a thickness of 0.7 mm, and a width of the peripheral flange of the upper opening of 5 mm. About 200 ml of water was added, and the polyethylene film was fused and sealed to the flange portion at the periphery of the upper opening of the cup.
Using 20 of these sealed containers, a drop impact resistance test was performed to measure the minimum height at which the container body cracks due to free fall under a low temperature environment of 5 ° C. As a result, the product of the present invention was not changed in the sealed container even when dropped from 2 m.

[Comparative Example 13]
The same procedure as in Example 6 was performed except that organic mica was not used. However, the fluidity of the resin was poor, making it impossible to make a cup with an internal volume of about 250 ml.

As is apparent from the evaluation results of Table 1, the molded bodies of Examples 1 to 5 of the present invention have barrier properties and can exhibit high fluidity by adopting specific molding materials. It can be seen that the molded article exhibits excellent impact resistance. That is, it can be seen that the barrier property and impact resistance are good, the fluidity is appropriate, the physical properties of the molded article are not significantly reduced, and the moldability is good.
On the other hand, it can be seen that the molded bodies of Comparative Examples 1 to 12 have a poor result of performance evaluation of one or more of barrier properties, moldability, and physical properties of the molded bodies. Further, as is clear from Comparative Examples 1, 10, and 12, it can be seen that the polypropylene resin has low impact strength at low temperatures.

  As described above, according to the present invention, according to the present invention, not only the gas barrier property, particularly the oxygen permeation prevention property, is excellent, but also the moldability, the appearance of the molded product, the mechanical strength, the impact resistance, particularly the DuPont type. A polyethylene container excellent in weight drop resistance, for example, a gas barrier cup-shaped container, can be obtained, and its characteristics can be used in a wide range of fields including various container fields, so that the industrial utility is very high.

Claims (5)

Organized layered silicate (A) 5 to 30% by weight, density is 0.920 to 0.940 g / cm ³ , temperature is 190 ° C., and melt flow rate (MFR) measured at a load of 2.16 kg is 1 to 1. A polyethylene-based container comprising 70 to 95% by weight of a polar group-containing polyethylene (B) that is 30 g / 10 min and satisfying the following characteristics (1) to (4).
Characteristic (1): Viscosity η ₄₈ (Pa · s) measured at a temperature of 190 ° C. and a shear rate of ₄₈ sec ⁻¹ with a capillary rheometer and a viscosity η ₃₁₀₀ (Pa · s) measured at a shear rate of ₃₁₀₀ sec ⁻¹ The ratio (η ₄₈ / η ₃₁₀₀ ) is 7-30.
Characteristic (2): Oxygen permeability coefficient P (cm ³ · mm / m ² · 24 hr · atm) (23 ° C. · 65% RH) of polyethylene container and polar group-containing polyethylene (B oxygen permeability coefficient _{^{P 0 (cm 3 · mm /}} m 2 · 24hr · atm) the ratio P / _{P 0} of (23 ℃ · 65% RH) of) is 0.7 or less.
Characteristic (3): The flexural modulus is 900 MPa or more.
Characteristic (4): 50% fracture energy (E ₅₀ ) of DuPont weight resistance to fall is 110 to 300 kgf · cm at 23 ° C. and 100 to 250 kgf · cm at −30 ° C.   2. The polyethylene container according to claim 1, wherein the layered silicate used in the organically modified layered silicate (A) is montmorillonite and / or mica.   The polyethylene container according to claim 1 or 2, wherein the polar group-containing polyethylene (B) contains 0.1 to 5.0% by weight of an unsaturated carboxylic acid and / or a derivative thereof.   The polyethylene container according to any one of claims 1 to 3, which is formed by injection molding.   The polyethylene container according to any one of claims 1 to 4, wherein the container is a cup.