JP2002003610A - Method of manufacturing resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a resin composition which has superior gas barrier and appearance characteristics, furthermore superior impact resistance property. SOLUTION: The resin composition is manufactured by blending in a molten state a saponified copolymer of ethylene-vinyl acetate (A) which has water content of 50 wt.% or less, a water swellable, lamellar inorganic compound (B) and a thermoplastic resin (C).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a resin composition comprising a saponified ethylene-vinyl acetate copolymer (A), a water-swellable layered inorganic compound (B) and a thermoplastic resin (C). More specifically, the present invention relates to a method for producing a resin composition having excellent gas barrier properties and appearance properties, and also excellent impact resistance.

[0002]

2. Description of the Related Art In general, saponified ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVOH) is excellent in transparency, antistatic property, oil resistance, solvent resistance, gas barrier property, fragrance retention property and the like. It is a thermoplastic resin that can be melt-molded and is used for various packaging materials such as food packaging. In order to further improve gas barrier properties,
Attempts have been made to mix inorganic substances with VOH. For example, Japanese Patent Application Laid-Open No. 5-39392 discloses that E
Mixing VOH with a water-swellable phyllosilicate is described.

[0003]

However, as a result of a detailed study of the disclosed technology described in the above-mentioned publication, the present inventors have found that a water-swellable phyllosilicate is charged in the presence of water, Furthermore, since a water / alcohol solution of EVOH is added, so-called mamako is liable to be generated, which makes it difficult to uniformly disperse the water-swellable phyllosilicate, and a considerable time is required for uniform dispersion. found.

[0004] In the gas barrier properties, the technique only evaluates the barrier properties of a laminate in which polypropylene is laminated on the inner and outer layers, and it seems that there is still room for improvement in a single layer under high humidity. The disclosed technology does not consider impact resistance and the like when used in containers and the like, and further improvement in gas barrier properties and appearance and improvement in impact resistance are desired.

[0005]

Means for Solving the Problems Accordingly, the present inventors have conducted intensive studies in view of the above circumstances, and as a result, have found that EVOH
In producing a resin composition containing (A), a water-swellable layered inorganic compound (B) and a thermoplastic resin (C), EVOH (A) having a water content of 50% by weight or less, water-swellable layered inorganic The inventors have found that the above-mentioned problems can be solved by melt-mixing the compound (B) and the thermoplastic resin (C), and have completed the present invention.

The water content of the EVOH or the resin composition in the present invention is measured and calculated by the following method. [Measurement method of water content] After weighing EVOH or the resin composition with an electronic balance (W1: unit g), put it in a hot-air oven type drier maintained at 150 ° C, dry it for 5 hours, and further put it in a desiccator. The weight after allowing to cool for 30 minutes is similarly weighed (W2: unit g) and calculated from the following equation (2). Water content (%) = {(W1−W2) / W1} × 100 (2)

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The EVOH (A) used in the present invention is not particularly limited, but has an ethylene content of 5 to 60 mol% (further 10 to 60 mol%, particularly 20 to 55 mol%, particularly 25
To 50 mol%), and the ethylene content is 5%.
If the amount is less than mol%, the water resistance becomes insufficient, and conversely, 60 mol%
If it exceeds, the gas barrier properties are undesirably reduced.

The degree of saponification of the vinyl acetate component is preferably at least 90 mol% (more preferably at least 95 mol%, particularly at least 99 mol%, especially at least 99.5 mol%). If it is less than mol%, gas barrier properties and heat resistance become insufficient, which is not preferable.

The above EVOH (A) may be copolymerized with an ethylenically unsaturated monomer copolymerizable within a range not to impair the effects of the present invention (about 10 mol% or less). Examples of the compound include olefins such as propylene, 1-butene, and isobutene; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, (anhydrous) phthalic acid, (anhydrous) maleic acid, and (anhydrous) itaconic acid, or salts thereof. Or mono- or dialkyl esters having 1 to 18 carbon atoms, acrylamide, N-alkylacrylamide having 1 to 18 carbon atoms, N, N-dimethylacrylamide, 2-acrylamidopropanesulfonic acid or a salt thereof, acrylamidopropyldimethylamine or a acid thereof Acrylamides such as salts or quaternary salts thereof, methacrylamide, having 1 to 18 carbon atoms N- alkylmethacrylamide,
Methacrylamides such as N, N-dimethylmethacrylamide, 2-methacrylamidopropanesulfonic acid or a salt thereof, methacrylamidopropyldimethylamine or an acid salt or a quaternary salt thereof, N-vinylpyrrolidone, N-vinylformamide, N N-vinylamides such as vinylacetamide, vinyl cyanides such as acrylonitrile and methacrylonitrile, vinyl ethers such as alkyl vinyl ethers having 1 to 18 carbon atoms, hydroxyalkyl vinyl ethers and alkoxyalkyl vinyl ethers, vinyl chloride, vinylidene chloride, fluorine Vinyl halides such as vinyl chloride, vinylidene fluoride and vinyl bromide; vinyl silanes such as trimethoxy vinyl silane;
Allyl acetate, allyl chloride, allyl alcohol, dimethylallyl alcohol, trimethyl- (3-acrylamido-3-dimethylpropyl) -ammonium chloride, acrylamido-2-methylpropanesulfonic acid and the like can be mentioned. Further, post-modification such as urethanization, acetalization, and cyanoethylation may be performed as long as the gist of the present invention is not impaired.

In the present invention, it is necessary to adjust the water content of the EVOH (A) to 50% by weight or less when producing the target resin composition, and if the water content exceeds less than 50% by weight. A large amount of water cannot be blown out from the EVOH (A) during melt mixing, and the effect of the present invention is not exhibited. Although the lower limit of the water content is not particularly limited,
If the water content is less than 10% by weight, the apparent melting point of the EVOH (A) becomes high, and it is necessary to raise the set temperature of the extruder. Is not preferred. Also, EVOH
The upper limit of the water content of (A) is more preferably 35% by weight, and the lower limit is more preferably 12.5% by weight, particularly preferably 15% by weight.

The method for incorporating water into the EVOH (A) is not particularly limited, but it is preferable to uniformly contain water in the EVOH (A).
A method of precipitating a solution of EVOH (A) in water, washing thoroughly with water to remove the solvent and containing water, EVO in hot pressurized water
A method of treating H (A) for about 1 to 3 hours, EVOH
A method in which the paste after saponification of the ethylene-vinyl acetate copolymer during the production of (A) is precipitated in water to contain water, and the like. Among the above, a method in which the paste after saponification of the ethylene-vinyl acetate copolymer is deposited in water during the production of EVOH (A) is preferably used. still,
Simply mixing EVOH and water does not achieve the effects of the present invention because water is not uniformly contained in EVOH.

The water-swellable layered inorganic compound (B) used in the present invention is not particularly limited, and includes clay minerals such as smectite and vermiculite, and synthetic mica. Specific examples of the former smectite include Examples include montmorillonite, beidellite, nontronite, saponite, hectorite, sauconite, stevensite and the like. These may be natural or synthetic. In the present invention, the swelling degree of the water-swellable layered inorganic compound (B) (measured according to the standard test method volumetric method of the Bentonite Industry Association of Japan) is preferably large, and the swelling degree is at least 85 ml / 2 g ( And 90
It is preferable that the degree of swelling is less than 85 ml / 2 g, which is not preferable because the gas barrier property becomes insufficient.

In consideration of the degree of swelling, montmorillonite is preferred as the water-swellable layered inorganic compound (B). Further, water-swellable fluoromica-based minerals such as Na-type tetrasilicon mica, Na-type teniolite, Li-type teniolite, and Na-type hectorite are also preferably used. Also,
The aspect ratio of the water-swellable layered inorganic compound (B) is not particularly limited, but is preferably 500 or more.

The thermoplastic resin (C) used in the present invention includes polyolefin resin, polyester resin, polyamide resin, copolymerized polyamide, polystyrene resin, polyvinyl chloride resin, polyvinylidene chloride, acrylic resin, Examples thereof include vinyl ester resins, polyester elastomers, polyurethane elastomers, chlorinated polyethylene, chlorinated polypropylene, aromatic and aliphatic polyketones, aliphatic polyalcohols, and the like. Polyolefin resins are preferably used.

Examples of the polyolefin resin include linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), very low-density polyethylene (VLDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE). ), Ethylene-vinyl acetate copolymer (EVA), ionomer, ethylene-propylene (block or random) copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic ester copolymer, ethylene-methacrylic acid copolymer Coalesce, ethylene-methacrylate copolymer, polypropylene (P
P), propylene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymer, olefin homopolymer or copolymer such as polybutene, polypentene, polymethylpentene, or homopolymer or copolymer of these olefins And polyolefin-based resins in a broad sense such as those obtained by graft-modifying with an unsaturated carboxylic acid or an ester thereof, and blends thereof. Among these, the effect of improving impact resistance and the compatibility with EVOH (A) are listed. In consideration of the above, it is preferable to use an ethylene-vinyl acetate copolymer (EVA) or an ionomer. As the EVA, those having a high ethylene content are preferable, and further, it is preferable that a part or all of the vinyl acetate portion is saponified.

The ionomer is not particularly limited, and examples thereof include those in which the carboxyl group of the unsaturated carboxylic acid-modified ethylene-based resin is a metal salt type. A modified unsaturated carboxylic acid of ethylene or a copolymer of ethylene and various vinyl monomers, wherein the modified amount (content) of the unsaturated carboxylic acid is 4 to 15 mol% (more preferably 5 to 10 mol%). Mol%) is preferably used. Examples of the unsaturated carboxylic acid include ethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid, and ethylenically unsaturated monocarboxylic acids such as maleic acid, fumaric acid and itaconic acid. Saturated dicarboxylic acids or their anhydrides and half esters are exemplified. Examples of such metal salts include zinc salts, alkali metal salts, and alkaline earth metal salts. Specific examples include zinc salts, sodium salts, potassium salts, magnesium salts, calcium salts, barium salts, and lithium salts. And further modified with nylon or blended with a small amount of nylon. As the thermoplastic resin (C), one type may be selected from the above, or a mixture of two or more types may be used.

In the present invention, an EV having a water content of 50% by weight or less is used.
The most characteristic feature is that the desired resin composition is obtained by melting and mixing OH (A), the water-swellable layered inorganic compound (B) and the thermoplastic resin (C), and the method is specifically described. I do. When the above (A) to (C) are melt-mixed, there is no particular limitation. EVOH (A) having a water content of 50% by weight or less, a water-swellable layered inorganic compound (B) and a thermoplastic resin (C) are used. It can be put into a melt mixing device at once,
Alternatively, a device in which any one of EVOH (A) having a water content of 50% by weight or less, a water-swellable layered inorganic compound (B) and a thermoplastic resin (C) is previously blended and the other one is melt-mixed Or water content of 50% by weight
The following EVOH (A) and water-swellable layered inorganic compound (B)
And the thermoplastic resin (C) may be put into a melt-mixing apparatus, but the method is industrially preferable, and such a method will be specifically described but is not limited thereto. Not something.

The melt mixing of the present invention is not particularly limited, and may be performed using a known melt kneading (mixing) apparatus such as a melt extruder, a kneader ruder, a mixing roll, a Banbury mixer, a plast mill and the like. Although it is possible, it is usually industrially preferable to use a single-screw or twin-screw extruder, and in particular, a twin-screw extruder is suitably used in view of stability of melt-kneading, and a method using such a twin-screw extruder is preferred. , Will be described in more detail, but is not limited thereto.

The twin-screw extruder to be used is not particularly limited, but has an inner diameter of 20 mm or more (more preferably 30 to 150 m).
m) is preferable, and when the inner diameter is less than 20 mm, productivity is poor, which is not preferable.
To 80 (more preferably 30 to 60), and such L / D
If the diameter is less than 20, the mixing ability may be insufficient,
Conversely, if it exceeds 80, the residence time of the resin in the extruder becomes unnecessarily long, which is not preferable since thermal degradation is a concern.

EVOH (A) having a water content of 50% by weight or less,
Water-swellable layered inorganic compound (B) and thermoplastic resin (C)
Is supplied to a twin-screw extruder, EVOH (A) having a water content of 50% by weight or less and a water-swellable layered inorganic compound (B) are previously melt-blended and dried, and a thermoplastic resin (C) is added to the mixture. Feed into the hopper of the extruder or E
The melt-blended dried product (A + B) of VOH (A) and the water-swellable layered inorganic compound (B) is directly supplied to the hopper of the extruder, and the thermoplastic resin (C) is supplied from a part of the barrel of the extruder. (Side feed).

At this time, considering the dispersibility of the water-swellable layered inorganic compound (B), it is also preferable to prepare the water-swellable layered inorganic compound (B) in advance as an aqueous dispersion and supply it. The concentration of such an aqueous dispersion is preferably 0.1 to 10% by weight (more preferably 0.5 to 9% by weight, particularly 1 to 8.5% by weight, especially 2 to 8% by weight). Is 0.
If the content is less than 1% by weight, the total water content becomes too large to ensure the content of the water-swellable layered inorganic compound (B) in the resin composition, so that the processability at the time of melt-mixing deteriorates.
If it exceeds 0% by weight, the dispersibility of the water-swellable layered inorganic compound (B) is undesirably reduced.

EVOH (A) to be used for melt mixing
The mixing ratio of the water-swellable layered inorganic compound (B) and EVO is
The water-swellable layered inorganic compound (B) is 0.1 to 20 parts by weight (solid content) based on 100 parts by weight (solid content) of H (A).
(Furthermore, 0.5 to 15 parts by weight (same as left), especially 1 to 10 parts by weight
Parts by weight (same as left)). When the compounding ratio is less than 0.1 part by weight, the effect of improving gas barrier properties is small, and when it exceeds 20 parts by weight, the appearance of a molded product such as a film deteriorates. Not preferred.

EVOH (A) used for melt mixing
And the mixing ratio of the thermoplastic resin (C) and EVOH (A) 1
The thermoplastic resin (C) based on 00 parts by weight (solid content)
Is preferably 0.5 to 100 parts by weight (solid content) (more preferably 1 to 50 parts by weight (same as left), particularly 3 to 40 parts by weight (same as left)), and the compounding ratio is 0.5 part by weight. When the amount is less than 100 parts by weight, the effect of improving the impact resistance is poor. On the contrary, when the amount exceeds 100 parts by weight, the gas barrier property is reduced and the appearance of a molded product such as a film is undesirably reduced.

In the present invention, in carrying out the melt mixing of the present invention, it is preferable to select EVOH (A) so as to satisfy the condition of the following formula (1). E
By adjusting the ethylene content, the degree of saponification, and the water content of the VOH (A) so as to satisfy the following formula (1), the extrudability and gas barrier properties during melt mixing are improved.

That is, if the value of equation (1) is less than 60, EV
OH (A) and the water-swellable layered inorganic compound (B) are in a non-uniform mixed state, resulting in reduced gas barrier properties. Conversely, if it exceeds 120, extrusion processability during melt mixing is undesirably reduced. 60 ≦ (0.173 × Sv−20.111) × W + 0.2184 × (Sv−100) ² + 6.5356 × (Sv−100) + 230.67 × exp (−0.0074 × Et) ≦ 120・ (1) where Et: ethylene content (mol%), Sv: saponification degree (mol%), W: water content (wt%)

EVOH having a water content of 50% by weight or less
(A), the water-swellable layered inorganic compound (B) and the thermoplastic resin (C) are subjected to a twin-screw extruder to be melt-mixed. Regarding the shape of a die hole provided at the outlet of the extruder, Although not limited, consideration is given to obtaining a resin composition pellet having an appropriate shape and size (in the case of a columnar shape, the diameter is 1 to 10 mm and the length is 1 to 10 mm (furthermore, each is 2 to 6 mm)). If the diameter is 1 to 7 mm (and 2
５5 mm), and the number of holes is 3-100.
Approximately (more preferably, 10 to 50) are preferable for production. Further, it is also preferable to provide one or more (especially two or more) mesh screens between the extruder and the entrance of the die for removing foreign substances and stabilizing resin pressure (stabilization of extrusion). In consideration of this, it is also preferable to provide a gear pump, a heat exchanger, and the like.

In carrying out the melt-kneading, the temperature of the melt-mixing is not particularly limited, but it is usually preferable to form a temperature gradient in the extruder, and the temperature setting zone immediately below the hopper is set at 50 to 70 ° C. ~ 65 ° C, especially 5
0 to 60 ° C.), and the temperature of the intermediate portion thereafter is set to be 15 to 60 ° C. higher than that immediately after the lower portion of the hopper, and the set temperature of the extruder outlet immediately before the die is set to be lower than that of the intermediate portion by 0 to 60 ° C.
It is preferable to set the temperature lower by ４０40 ° C. In addition, the residence time of the resin composition in the extruder is selected from the range of 10 to 600 seconds (further 20 to 300 seconds, particularly 30 to 240 seconds). Mixing may not be possible, and if it exceeds 600 seconds, the quality of the resin composition may deteriorate, which is not preferable. The pressure applied to the resin composition (resin pressure) is 5 to 300 k.
g / cm ² (more 10 to 200 / cm ²⁾ is selected from the range of less than such pressure is 5 kg / cm ² and 30
Exceeding 0 kg / cm ² is not preferred because extrusion may become unstable. It is also preferable to seal the inside of the hopper and around the vent hole with nitrogen in order to prevent the thermal deterioration of the resin composition.

The screw rotation speed is 50 to 500 r.
pm (furthermore, from 80 to 400 rpm). When the number of revolutions is less than 50 rpm, the mixing ability may be insufficient. On the other hand, when the number of revolutions exceeds 500 rpm, the quality of the resin composition may deteriorate. However, the charging speed of EVOH (A) having a water content of 50% by weight or less is not particularly limited, and may be arbitrarily determined according to the barrel diameter of the extruder. Further, regarding the charging speed of the water-swellable layered inorganic compound (B) and the thermoplastic resin (C),
What is necessary is just to supply according to said EVOH (A) according to the compounding quantity of the water-swellable layered inorganic compound (B) and thermoplastic resin (C) in the target resin composition.

The resin composition thus melt-mixed is extruded from a strand die, cooled and cut, and then dried to obtain a desired resin composition (pellet).

The resin composition (pellet) obtained by the production method of the present invention is frequently used for molded articles, and is formed into films, sheets, containers, fibers, rods, tubes, various molded articles, etc. by melt molding or the like. It is also possible to use these crushed products (such as when reusing recovered products) again for melt molding,
As such a melt molding method, an extrusion molding method (T-die extrusion, inflation extrusion, blow molding, melt spinning, profile extrusion, etc.) and an injection molding method are mainly employed. The melt molding temperature is often selected from the range of 150 to 300 ° C.

Further, the resin composition (pellet) obtained by the production method of the present invention can be used as a single molded product. Specifically, it is useful to laminate a thermoplastic resin layer or the like on at least one side of a layer made of the resin composition and use it as a molded product of a multilayer laminate.

In producing the laminate, another substrate is laminated on one or both sides of a layer composed of the resin composition. The lamination method is, for example, a film or sheet composed of the resin composition. A method of melt-extruding a thermoplastic resin, a method of melt-extruding the resin composition on a substrate such as a thermoplastic resin, a method of co-extruding the resin composition with another thermoplastic resin, Examples of the method include dry laminating a film or sheet made of the resin composition of the present invention with a film or sheet of another substrate using a known adhesive such as an organic titanium compound, an isocyanate compound, a polyester compound, or a polyurethane compound. Can be It is also preferable that the resin composition (pellet) obtained by the production method of the present invention is subjected to coextrusion molding.

In the case of co-extrusion, the other resin is a polyolefin resin, a polyester resin, a polyamide resin, a copolymerized polyamide, a polystyrene resin, a polyvinyl chloride resin, a polyvinylidene chloride, an acrylic resin,
Examples thereof include vinyl ester resins, polyester elastomers, polyurethane elastomers, chlorinated polyethylene, chlorinated polypropylene, aromatic and aliphatic polyketones, aliphatic polyalcohols, and the like. Polyolefin resins are preferably used.

Specific examples of the polyolefin resin include linear low density polyethylene (LLDPE), low density polyethylene (LDPE), very low density polyethylene (VLDPE), medium density polyethylene (MDPE), and high density polyethylene (HDPE). ), Ethylene-vinyl acetate copolymer (EVA), ionomer, ethylene-propylene (block or random) copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic ester copolymer, ethylene-methacrylic acid copolymer Coalesce, ethylene-methacrylic acid ester copolymer, polypropylene, propylene-α-olefin (C 4-20 α-olefin) copolymer, polybutene, polypentene, homo- or copolymer of olefin such as polymethylpentene, Alternatively, these olefins are simply Examples include polyolefin resins in a broad sense, such as those obtained by graft-modifying a homopolymer or a copolymer with an unsaturated carboxylic acid or an ester thereof, and blends thereof. Among them, linear low-density polyethylene (L
LDPE), low-density polyethylene (LDPE), very low-density polyethylene (VLDPE), ethylene-vinyl acetate copolymer (EVA), and ionomer are excellent in bending fatigue resistance, vibration fatigue resistance, and the like of the obtained laminated packaging material. It is preferred in that respect.

Further, a molded product such as a film or a sheet is once obtained from the resin composition (pellet) obtained by the production method of the present invention, and another substrate is extrusion-coated thereon, or a film of another substrate is formed. When laminating a sheet or the like using an adhesive, an arbitrary substrate (paper, metal foil, non-stretched, uniaxially or biaxially stretched plastic film or sheet and its inorganic vapor-deposited body, woven fabric, in addition to the above-mentioned thermoplastic resin) , Nonwoven fabric, metal flocculent, woody, etc.) can be used.

The layer structure of the laminate is obtained by the production method of the present invention.
A layer composed of the obtained resin composition (pellet)₁,
a_Two,...), Other substrates, for example, a thermoplastic resin layer b
(B₁, B_Two, ...), a film, a sheet,
In the case of a bottle, not only the two-layer structure of a / b but also b /
a / b, a / b / a, a₁/ A_Two/ B, a / b₁/ B_Two, B
_Two/ B₁/ A / b₁/ B_Two, B₁/ B_Two/ A / b_Three/ B_Four, A₁
/ B₁/ A_Two/ B_TwoAny combination is possible.
In the filament form, a and b are bimetallic, core (a) -sheath
(B) type, core (b) -sheath (a) type, eccentric core-sheath type, etc.
Any combination is possible.

In the above-mentioned layer structure, an adhesive resin layer can be provided between the respective layers as required. Various kinds of adhesive resins can be used. Although it differs depending on the type of the resin and cannot be stated unconditionally, the carboxyl obtained by chemically bonding an unsaturated carboxylic acid or its anhydride to an olefin polymer (the above-mentioned polyolefin resin in a broad sense) by an addition reaction, a graft reaction or the like. Examples of the modified olefin polymer having a group include a maleic anhydride-grafted polyethylene, a maleic anhydride-grafted polypropylene, and a maleic anhydride-grafted ethylene-propylene (block or random) copolymer. , Maleic anhydride graft-modified ethylene-ethyl acrylate copolymer, maleic anhydride Graft-modified ethylene - one or a mixture of two or more species selected from vinyl acetate copolymers and the like as preferred. At this time, the amount of the unsaturated carboxylic acid or its anhydride contained in the olefin polymer is preferably 0.001 to 3% by weight, more preferably 0.01 to 1% by weight, and particularly preferably 0.1 to 1% by weight. 03-
0.5% by weight. When the amount of modification in the modified product is small,
Adhesiveness may be insufficient, and if it is too high, a crosslinking reaction may occur, resulting in poor moldability.
These adhesive resins include resin compositions (pellets) obtained by the production method of the present invention, other rubber / elastomer components such as EVOH, polyisobutylene, and ethylene-propylene rubber, and resins of the b layer. Can be blended. In particular, by blending a polyolefin resin different from the base polyolefin resin of the adhesive resin, the adhesiveness may be improved, which is useful.

The thickness of each layer of the laminate cannot be specified unconditionally depending on the layer constitution, the type of b, the use and the form of the container, the required physical properties, and the like.
0 to 200 μm), and the layer b is 5 to 5000 μm (and 3
0-1000 μm), the adhesive resin layer is 5-400 μm
(Further 10 to 150 μm). If the thickness of the a layer is less than 5 μm, the gas barrier properties are insufficient, and the thickness control becomes unstable. Conversely, if the thickness exceeds 500 μm, the bending fatigue resistance is inferior. Run short, and conversely 50
If it exceeds 00 μm, the bending fatigue resistance is inferior and the weight becomes large, which is not preferable. If the adhesive resin layer is less than 5 μm, the interlayer adhesion becomes insufficient, and the thickness control becomes unstable. And it is not economical and not preferable. Also, each layer of the laminate has
In order to improve moldability and various physical properties, the above-mentioned various additives, modifiers, fillers, other resins, and the like can be added within a range that does not impair the effects of the present invention.

The laminate is used as it is in various shapes. However, in order to further improve the physical properties of the laminate, it is preferable to perform a stretching treatment.
Any of uniaxial stretching and biaxial stretching may be performed, and it is better to perform stretching at as high a magnification as possible in terms of physical properties, and a stretched film or a stretched sheet free from pinholes, cracks, stretch unevenness, delamination, etc. A molded product such as a stretching container or a stretching bottle is obtained.

The stretching method includes a roll stretching method, a tenter stretching method, a tubular stretching method, a stretching blow method, and the like.
Among the deep drawing forming, vacuum press forming and the like, those having a high stretching ratio can be employed. In the case of biaxial stretching, any of a simultaneous biaxial stretching method and a sequential biaxial stretching method can be adopted. The stretching temperature is selected from the range of 60 to 170 ° C, preferably about 80 to 160 ° C.

After completion of the stretching, it is also preferable to carry out heat setting. . The heat setting can be carried out by a known means, and the stretched film is kept at a tension of 80 to 1 while being kept in tension.
Heat treatment is performed at 70 ° C., preferably 100 to 160 ° C. for about 2 to 600 seconds. For example, when a cup or tray-shaped multilayer container is obtained from a multilayer sheet or a multilayer film, a drawing method is employed, and specifically, a vacuum forming method, a pressure forming method,
Vacuum pressure forming method, plug assist type vacuum pressure forming method and the like can be mentioned.

Further, when a tube or a bottle-shaped multilayer container is obtained from a multilayer parison (a hollow tubular preform before blowing), a blow molding method is employed. Specifically, an extrusion blow molding method (double head type, mold) Mobile, parison shift, rotary, accumulator, horizontal parison, etc.)
Cold parison type blow molding method, injection blow molding method,
Biaxial stretch blow molding (extrusion cold parison biaxial stretch blow molding, injection cold parison biaxial stretch blow molding, injection molding in-line biaxial stretch blow molding, etc.) and the like.

When used for heat shrink wrapping of raw meat, processed meat, cheese, etc., it is used as a product film without heat setting after stretching, and the above raw meat, processed meat, cheese, etc. are stored in the film. After that, 50-130 ° C., preferably 70
The film is subjected to a heat treatment at about 120 ° C. for about 2 to 300 seconds to thermally shrink the film, thereby performing tight packaging.

The shape of the laminate thus obtained may be arbitrary, and examples thereof include a film, a sheet, a tape, a bottle, a pipe, a filament, and an extrudate having a modified cross section. Further, the obtained laminate is heat-treated, cooled, rolled, printed, dry-laminated,
Solution or melt coating processing, bag making processing, deep drawing processing, box processing, tube processing, split processing, and the like can be performed.

The containers such as cups, trays, tubes, bottles and the like obtained as described above, bags and lids made of stretched films are not only general foods, but also seasonings such as mayonnaise and dressings, and fermented foods such as miso. , Salad oils and other fat foods, beverages, cosmetics, pharmaceuticals, detergents, cosmetics, industrial chemicals,
Although useful as various containers for agricultural chemicals and fuels, the laminate of the present invention is particularly useful for containers for fuels and the like.

[0046]

The present invention will be specifically described below with reference to examples. In the examples, “parts” and “%” are based on weight unless otherwise specified.

Example 1 EVOH (A) having a water content of 28% [ethylene content 32 mol%, degree of saponification 99.8 mol%] was 132 parts / minute [EV
OH 95 parts (solid content)], and natural montmorillonite (B) [swelling degree (measured according to the standard test method volume method of Japan Bentonite Industry Association) 97 ml / 2 g] is 5 parts /
At the same time, twin-screw extruder (L / D = 42 30m
mφ], and melt-mixed. (A)
The water content of the entire composition at the time of melt mixing of (B) and (B) was 27%.

The temperature setting zone immediately below the hopper is 5
The temperature was set at 0 ° C., the temperature at the middle part was set at 98 ° C., and the temperature at the outlet of the extruder was set at 90 ° C. Then, a mixture of (A) and (B) is extruded in a strand form from a strand die provided at the outlet of the extruder, cut, and resin composition pellets (water content: 24%); diameter: 2.5 mm, length 3
mm cylindrical shape).

The residence time of the mixture in the extruder is 3
In minutes, the resin pressure was 35 kg / cm ² . In addition, the ethylene content (32 mol%), the saponification degree (99.8 mol%) and the water content (28
%), It was 101.1, which satisfied the expression (1). Next, the obtained pellets were vacuum-dried at 60 ° C. to obtain pellets of a mixture of (A) and (B) (water content: 0.3%).

The pellet (A + B) and an ionomer (“HIMILAN AM792” manufactured by DuPont-Mitsui Polychemicals, Inc.)
61 ", containing 6,66 nylon, Zn-based)
(Weight ratio) and dry blending, temperature setting 23
The mixture was charged into a twin-screw extruder (30 mmφ, L / D = 42) at 0 ° C., melt-mixed, extruded into strands and cut to obtain resin composition pellets.

The above pellets were supplied to a single screw extruder,
A film was formed by a die casting method under the condition of an extruder set temperature of 230 ° C. to obtain a 30 μm film. The following evaluation was performed about the obtained film.

(Oxygen permeability) The obtained film was treated with MO
The measurement was carried out under the conditions of 20 ° C. and 80% RH by an isobaric method (MOCON method) using “OXTRAN 2/20” manufactured by CON Corporation.

(Appearance Characteristics) In the obtained film,
The number of foreign substances having a diameter of 0.2 mm or more in 10 cm × 10 cm was measured and evaluated according to the following criteria. ◎ ・ ・ ・ 2 or less ○ ・ ・ ・ 3 to 5 × ・ ・ ・ 6 or more

(Impact Resistance: Film Impact Strength) The obtained film (12 cm × 12 cm, 30 μm thickness) was subjected to YSS
Type film impact tester (manufactured by Yasuda Seiki Seisakusho)
The film impact strength (kgf-cm) was measured. The measurement was performed three times, and the average value was defined as the film impact strength.

Example 2 In Example 1, (A + B) was obtained by using EVA (“Mersen H6960” manufactured by Tosoh Corporation, ethylene content 82 mol%, saponification degree 90 mol%) (C) as the thermoplastic resin.
/ (C) = 90/10 (weight ratio) except that the resin composition was pelletized (water content: 0.3%) and evaluated in the same manner as in Example 1.

Example 3 A resin was prepared in the same manner as in Example 1 except that EVA ("Mersen H6051" manufactured by Tosoh Corporation, ethylene content 89 mol%, fully saponified product) (C) was used as the thermoplastic resin. A pellet (water content: 0.3%) of the composition was obtained, and the same evaluation as in Example 1 was performed.

Example 4 Example 1 was repeated except that the water content was 32% and the ethylene content was 29.
Mol%, EVOH (A) having a saponification degree of 99.7 mol%, and the input amount was set to 144 parts / minute [EVOH 98 parts (solid content)]. Natural montmorillonite (B) [swelling degree (Japan Bentonite Industry Association) Is measured in accordance with the standard test method, volumetric method), 98 ml / 2 g] is continuously supplied at a rate of 2 parts / min, and the set temperature of the intermediate part (vent part) is changed to 95 ° C. This was performed to obtain pellets of the resin composition (water content: 0.3%), and the same evaluation as in Example 1 was performed.

The water content of the whole composition at the time of mixing (A) and (B) is 32%, and the water content of the pellet before drying is 29%.
%, And the ethylene content (29 mol%), the degree of saponification (99.7 mol%) and the water content (32%) of EVOH (A) are substituted into the formula (1) in the text. As a result, the expression (1) was satisfied.

Example 5 In Example 1, natural montmorillonite (B) was replaced with Na
Type fluorine tetrasilicic mica [The degree of swelling (measured according to the standard test method volumetric method of Japan Bentonite Industry Association) is 96 ml / 2
g] and continuously supply at a rate of 5 parts / min.
Further, except that the set temperature of the intermediate portion (vent portion) was changed to 105 ° C., the same procedure was performed to obtain pellets of the resin composition (water content: 0.3%), and the same evaluation as in Example 1 was performed.
Incidentally, the water content of the whole composition at the time of mixing (A) and (B) is 2
At 7%, the moisture content of the pellets before drying was 23%.

Example 6 The procedure of Example 1 was repeated except that EVO having an ethylene content of 38 mol% was used.
Using H (A), except that the water content was 25%, the same procedure was performed to obtain pellets of the resin composition (water content 0.3%), and the same evaluation as in Example 1 was performed. The water content of the whole composition at the time of mixing (A) and (B) was 24%, the water content of the pellet before drying was 21%, and EVOH (A) was used in the expression (1) in the text. Of ethylene (38 mol%), saponification degree (99.8 mol%) and water content (25 mol%)
%), It was 101.7, which satisfied the expression (1).

Example 7 In Example 1, EVOH having a saponification degree of 98 mol% was used.
Except for using (A), the same procedure was carried out to obtain pellets of the resin composition (water content: 0.3%), and the same evaluation as in Example 1 was performed. The water content of the whole composition at the time of mixing (A) and (B) was 27%, and the water content of the pellet before drying was 23%.
In addition, when the ethylene content (32 mol%), the degree of saponification (98 mol%) and the water content (28%) of the EVOH (A) are substituted into the expression (1) in the text, it becomes 81.4. (1)
The expression was satisfied.

Comparative Example 1 Pellets of a resin composition (water content: 0.3%) were obtained in the same manner as in Example 1 except that EVOH (A) having a water content of 60% was used. The same evaluation was performed.
Incidentally, the water content of the whole composition at the time of mixing (A) and (B) is 5
At 9%, the moisture content of the pellets before drying was 54%.

Comparative Example 2 The same evaluation as in Example 1 was performed on pellets of a mixture of only EVOH (A) and natural montmorillonite (B) in Example 1.

Table 1 shows the results of Examples and Comparative Examples.

[Table 1] Oxygen permeability Appearance characteristics Film impact strength (cc · 30 μm / m ² · day · atm) (kgf-cm) Example 1 0.2 ◎ 22 〃 2 0.2 ◎ 14 〃 30 1.2 １１ 11 ４ 40.2 17 ５ 5 0.3 ◎ 10 ６ 6 0.4 ◎ 20 ７ 7 0.4 １８ 18 Comparative Example 1 1.2 × 4 〃 20.4 ◎ 4

[0066]

According to the production method of the present invention, EVOH (A)
Water-swellable layered inorganic compound (B) and thermoplastic resin (C)
In the production of a resin composition containing the following, EVOH (A) having a water content of 50% by weight or less, a water-swellable layered inorganic compound (B), and a thermoplastic resin (C) are melt-mixed. The resin composition obtained is excellent in gas barrier properties and appearance properties, and furthermore exhibits excellent impact resistance.These resin compositions are used for films, sheets, containers, and the like, and are used for general foods, retort foods, It is useful as various packaging materials for pharmaceuticals, industrial chemicals, agricultural chemicals, etc., and it is also effective to laminate it with various resins, and is particularly useful for containers such as gasoline tanks and agricultural chemical bottles.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) C08L 23/26 C08L 23/26 29/04 29/04 S 101/00 101/00 F term (reference) 4F070 AA12 AA13 AA28 AA29 AB01 AB02 AB09 AB11 AC11 AC27 AD01 DA12 DC11 FA03 FA06 FB06 4J002 BB022 BB062 BB072 BB082 BB112 BB152 BB172 BB221 BB232 BB242 BC022 BD032 BD102 BE031 BF012 BG002 BG03 002 012

Claims (9)

[Claims] 1. A method for producing a resin composition comprising a saponified ethylene-vinyl acetate copolymer (A), a water-swellable layered inorganic compound (B) and a thermoplastic resin (C), comprising a water content of 50%. A method for producing a resin composition, comprising: melting and mixing an ethylene-vinyl acetate copolymer saponified product (A), a water-swellable layered inorganic compound (B) and a thermoplastic resin (C) in an amount of not more than 10% by weight. . 2. A saponified ethylene-vinyl acetate copolymer (A) satisfying the following formula (1) and having a water content of 50% by weight or less.
The method for producing a resin composition according to claim 1, wherein the resin composition is used. 60 ≦ (0.173 × Sv−20.111) × W + 0.2184 × (Sv−100) ² + 6.5356 × (Sv−100) + 230.67 × exp (−0.0074 × Et) ≦ 120・ (1) where Et: ethylene content (mol%), Sv: saponification degree (mol%), W: water content (wt%) 3. The method for producing a resin composition according to claim 1, wherein the lower limit of the water content of the entire resin composition at the time of melt mixing is set to 10% by weight. 4. The resin according to claim 1, wherein the lower limit of the water content of the saponified ethylene-vinyl acetate copolymer (A) having a water content of 50% by weight or less is 10% by weight. A method for producing the composition. 5. The water-swellable layered inorganic compound (B) content is 0.1 to 20 parts by weight based on 100 parts by weight of a saponified ethylene-vinyl acetate copolymer (A). 5. The method for producing the resin composition according to any one of 1 to 4. 6. A method according to claim 1, wherein the content of the thermoplastic resin (C) is 0.5 to 100 parts by weight based on 100 parts by weight of the saponified ethylene-vinyl acetate copolymer (A). A method for producing the resin composition according to any one of the above. 7. The method for producing a resin composition according to claim 1, wherein the thermoplastic resin (C) is a polyolefin resin. 8. The method for producing a resin composition according to claim 7, wherein the polyolefin resin is at least one selected from an ethylene-vinyl acetate copolymer and an ionomer. 9. The method for producing a resin composition according to claim 1, wherein the resin composition is formed into a pellet.