JP2002003613A - Method of manufacturing resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a resin composition having a better gas barrier property and a better appearance. SOLUTION: When manufacturing a resin composition comprising a saponified ethylene-vinylacetate copolymer (A) and an inorganic compound having a layer structure and a water swelling property (B), the saponified product of ethylene- vinylacetate copolymer (A) having a water content of 40 wt.% or less and an aqueous dispersion of the inorganic compound having the layer structure and the water swelling property (B) are melt mixed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a resin composition comprising a saponified ethylene-vinyl acetate copolymer (A) and a water-swellable layered inorganic compound (B). The present invention relates to a method for producing a resin composition having excellent appearance characteristics.

[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, Further, 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. There was found. Also, with regard to gas barrier properties, this 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 and under high humidity. In view of the sophistication of gas, further improvement in gas barrier properties is desired.

[0004]

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) and the water-swellable layered inorganic compound (B), an EVOH (A) having a water content of 40% by weight or less and an aqueous dispersion of the water-swellable layered inorganic compound (B) The present inventors have found that the above-mentioned problems can be solved by melt-mixing the above and have completed the present invention.

Further, in the present invention, the effect of the invention can be remarkably obtained by using EVOH (A) having a water content of 40% by weight or less which satisfies the following formula (1). 75 ≦ (0.173 × Sv−20.111) × W + 0.2184 × (Sv−100) ² + 6.5356 × (Sv−100) + 230.67 × exp (−0.0074 × Et) ≦ 135 -(1) However, Et represents ethylene content (mol%), Sv represents saponification degree (mol%), and W represents water content (wt%).

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 EVOH (A) to 40% by weight or less when producing the desired resin composition. A large amount of water cannot be blown out from the EVOH (A) during mixing, and the effect of the present invention is not exhibited. The lower limit of the water content is not particularly limited, but is preferably 10% by weight. If the water content is less than 10% by weight, the apparent melting point of EVOH (A) becomes high,
It is necessary to raise the set temperature of the extruder, and as a result, the resin composition foams, which is not preferable. Also, EVOH (A)
The upper limit of the water content is preferably 35% by weight, more preferably 30% by weight, and the lower limit is more preferably 12.5% by weight, particularly 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.

In the present invention, it is necessary to prepare the water-swellable layered inorganic compound (B) as an aqueous dispersion when producing the desired resin composition. In order to obtain such an aqueous dispersion, a known stirring device is used. A high-pressure dispersing device such as an ultra-high-pressure homogenizer, a ball mill, an ultrasonic treatment device, or the like can be used to further improve the dispersibility.

The concentration of the aqueous dispersion is not particularly limited, but is 0.1 to 10% by weight (further 0.5 to 9% by weight, particularly 1 to 8.5% by weight, particularly 2 to 8% by weight). % By weight), and when the concentration is less than 0.1% by weight, the overall water content becomes too large in an attempt to secure the content of the water-swellable layered inorganic compound (B) in the resin composition. As a result, the processability at the time of melt-mixing decreases, and if it exceeds 10% by weight, the dispersibility of the water-swellable layered inorganic compound (B) decreases, which is not preferable. In the present invention, a water content of 4
The most characteristic feature is that the EVOH (A) of 0% by weight or less and the aqueous dispersion of the water-swellable layered inorganic compound (B) are melt-mixed. Such melt-mixing will be described.

The melting and mixing of the EVOH (A) having a water content of 40% by weight or less and the aqueous dispersion of the water-swellable layered inorganic compound (B) are not particularly limited. For example, a melt extruder, a kneader ruder, a mixing roll, It can be carried out using a known melt-kneading (mixing) apparatus such as a Banbury mixer or a plastomill. However, it is usually industrially preferable to use a single-screw or twin-screw extruder, and in particular, in view of stability of melt-kneading. A twin-screw extruder is suitably used, and a method using such a twin-screw extruder will be described in more detail, but is not limited thereto. The twin-screw extruder to be used is not particularly limited, but one having an inner diameter of 20 mm or more (more preferably 30 to 150 mm) is preferable.
When the thickness is less than 0 mm, productivity is poor, which is not preferable.
/ D is preferably 20 to 80 (more preferably 30 to 60),
When the L / D diameter is less than 20, the mixing ability may be insufficient. On the other hand, when the L / D diameter is more than 80, the residence time of the resin in the extruder becomes unnecessarily long.

The supply of the aqueous dispersion of the EVOH (A) having a water content of 40% by weight or less and the water-swellable laminar inorganic compound (B) to the twin-screw extruder is not particularly limited, and such (A) and (B) A method in which a mixture in which a dispersion is preblended is supplied to a hopper of the extruder; a method in which the dispersion liquid (A) and (B) is directly supplied to a hopper of the extruder; And (B) a method of supplying the dispersion liquid from a part of the barrel of the extruder (side feed).
The method of is preferred, in performing such a method,
The aqueous solution can be supplied from the vent using gravity, or can be supplied under pressure.

In the present invention, the water content is 40% by weight.
The following EVOH (A) and water-swellable layered inorganic compound (B)
When the dispersion is melt-mixed, the water content of the entire resin composition at the time of mixing is preferably set to 20 to 60% by weight (more preferably 22.5 to 50% by weight, particularly 25 to 45% by weight), If the water content is less than 20% by weight, the dispersibility of the water-swellable layered inorganic compound (B) becomes insufficient, and if it exceeds 60% by weight, the EVOH (A) and the dispersion become in an unevenly mixed state. Is not preferred.

The mixing ratio of the EVOH (A) having a water content of 40% by weight or less and the water-swellable layered inorganic compound (B) dispersion liquid to be melt-mixed is 100 parts by weight of EVOH (A) (solid content). Water swellable layered inorganic compound (B)
Is 0.1 to 20 parts by weight (solid content) (further 0.5 to 15 parts by weight)
Parts by weight (same as left), particularly preferably 1 to 10 parts by weight (same 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, which is not preferable.

In the present invention, first, the target EVO
The blending (mixing) ratio of H (A) and the water-swellable layered inorganic compound (B) is determined, and the moisture content and water swelling of the EVOH (A) are taken into account while considering the moisture content of the entire resin composition at the time of mixing. What is necessary is just to determine the density | concentration of an aqueous layered inorganic compound (B) dispersion liquid, and to provide it for melt mixing. Furthermore, in the present invention, a water content of 40
It is also preferable to select EVOH (A) so as to satisfy the condition of the following formula (1) when melt-mixing the EVOH (A) having a weight percent or less and the dispersion of the water-swellable layered inorganic compound (B). By preparing the EVOH (A) so that the ethylene content, the degree of saponification, and the water content thereof satisfy the following formula (1), the extrudability with the dispersion and the gas barrier property are improved.

That is, if the value of equation (1) is less than 75, EV
OH (A) and the dispersion liquid are in a non-uniform mixed state and the gas barrier property is lowered. On the other hand, when it exceeds 135, the extrusion processability is lowered, which is not preferable. 75 ≦ (0.173 × Sv−20.111) × W + 0.2184 × (Sv−100) ² + 6.5356 × (Sv−100) + 230.67 × exp (−0.0074 × Et) ≦ 135 -(1) However, Et represents ethylene content (mol%), Sv represents saponification degree (mol%), and W represents water content (wt%).

EVOH having a water content of 40% by weight or less
The dispersion of (A) and the water-swellable layered inorganic compound (B) is subjected to a twin-screw extruder to be melt-mixed. The shape of a die hole provided at the outlet of the extruder is not limited, but is not limited. Shape and size [In the case of a columnar shape, the diameter is 1 to 10
mm, length of 1 to 10 mm (furthermore, each of 2 to 6 mm
In consideration of obtaining a resin composition pellet having a diameter of 1 mm, a circle having a diameter of 1 to 7 mm (more preferably 2 to 5 mm) is preferable, and the number of holes is 3 to 100 (more preferably 10 to 10).
About 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. (furthermore, 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. The charging rate of EVOH (A) having a water content of 40% by weight or less is not particularly limited, and may be arbitrarily determined according to the barrel diameter of the extruder. The charging rate of the dispersion of the water-swellable layered inorganic compound (B) is adjusted so as to match the blending amount of (B) in the target resin composition.
What is necessary is just to supply according to (A). The melt-mixed resin composition is then supplied to a die and extruded. The temperature of the resin composition in the die is 80 to 100 ° C.
It is also preferable to adjust the extrusion conditions (setting temperature, screw shape, screw rotation speed, etc.) so that the temperature becomes 85 to 100 ° C. If the temperature is lower than 80 ° C, the extrusion may be unstable. On the other hand, when the temperature exceeds 100 ° C., the quality of the resin composition may deteriorate, which is not preferable.

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). As such a drying treatment, it is possible to adopt various drying methods, for example,
Fluid drying or standing drying can be performed. Such fluid drying means drying performed while the resin composition (pellet) is substantially stirred or dispersed by mechanical or hot air. Examples of the dryer include a cylindrical / groove type stirring dryer, a cylindrical dryer, a rotary dryer, a fluidized bed dryer, a vibration fluidized bed dryer, a conical rotary dryer, and the like. Means drying in which the resin composition (pellet) is substantially not subjected to a dynamic action such as stirring and dispersion, and is a batch type box as a dryer for performing the drying, and as a material stationary type. Examples of the material dryer include a band dryer, a tunnel dryer, a vertical silo dryer, and the like, but are not limited thereto.

By the drying treatment, the water content of the resin composition (pellet) is reduced to 0.1 to 3% by weight (further, 0.1 to 1% by weight).
%, Particularly 0.1 to 0.5% by weight). When the water content is less than 0.1% by weight, heat resistance becomes poor. On the contrary, when the water content exceeds 3% by weight, degassing occurs during molding. It is not preferable because it becomes insufficient and causes molding failure such as foaming. As another drying method, when the resin composition is melt-mixed with an extruder, moisture can be directly removed from the vent.

[0027] The resin composition (pellet) thus 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 can also be subjected to melt molding again using these pulverized products (for example, when reusing recovered products). As such a melt molding method, an extrusion molding method (T
-Die extrusion, inflation extrusion, blow molding, melt spinning, profile extrusion, etc.), and injection molding. The melt molding temperature is often selected from the range of 150 to 300 ° C.

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, polyester resin, polyamide resin, copolymerized polyamide, polystyrene resin, polyvinyl chloride resin, polyvinylidene chloride, acrylic resin, or the like.
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 obtained. 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-described 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 determined 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, but it is preferable to perform a stretching treatment in order to further improve the physical properties of the laminate.
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.

As a stretching method, besides 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., the product is not heat-set after stretching but is used as a product film, and the above-mentioned 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 thus obtained laminate may be any shape, 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, and the bags and lids made of stretched films obtained as described above 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.

[0043]

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 135 parts / minute [EV
OH 97 parts (solid content)] from a hopper into a twin-screw extruder (L / D = 42, 30 mmφ), and into natural montmorillonite (B) [degree of swelling (according to standard test method volumetric method of Japan Bentonite Industry Association). 98ml / 2g]
At a rate of 38 parts / min [3 parts of natural montmorillonite (solid content)] from the vent of the extruder, and the temperature was set to 95 ° C. Melt mixing was performed. The water content of the resin composition at the time of melt mixing is 42
%Met.

The temperature setting zone immediately after the lower part of the hopper is 5
The temperature was set to 0 ° C., the temperature of the intermediate portion (vent portion) was set to 95 ° C., and the set temperature of the extruder outlet was set to 90 ° C. Then, the resin composition is extruded in a strand form from a strand die provided at the outlet of the extruder, and cut to obtain a resin composition pellet (water content: 39%; cylindrical shape having a diameter of 2.5 mm and a length of 3 mm). Was.

The residence time of the resin composition in the extruder was 3 minutes, and the resin pressure was 20 kg / cm ² . In addition, the ethylene content of EVOH (A) (3
2 mol%), the degree of saponification (99.8 mol%) and the water content (28%) were substituted, which was 101.1, which satisfied the expression (1). Then, the obtained pellets were
Vacuum drying was performed at 0 ° C. to obtain pellets of the desired resin composition (water content: 0.3%).

The above pellets were fed to a single screw extruder,
A film was formed by a die casting method under the conditions of an extruder set temperature of 220 ° C. to obtain a 30 μm film. The following evaluation was performed about the obtained film.

(Oxygen permeability)
Using "OXTRAN 2/20" manufactured by CON Corporation, the measurement was carried out under the condition of 20 ° C. and 85% RH by an equal pressure method (MOCON method).

(Appearance Characteristics) In the obtained film,
The number of foreign substances having a diameter of 0.1 mm or more in 10 cm × 10 cm was measured and evaluated according to the following criteria. ◎ ・ ・ ・ 1 or less ○ ・ ・ ・ 2 to 5 × ・ ・ ・ 6 or more

Example 2 Example 1 was repeated except that the water content was 26% and the ethylene content was 29.
Mol%, EVOH (A) having a saponification degree of 99.7 mol% was used, and the input amount was 132 parts / minute [EVOH 98 parts (solid content)]. Natural montmorillonite (B) [swelling degree (Japan Bentonite Industry Association) 97 ml / 2 g] of the dispersion (concentration 6%) was continuously supplied at a rate of 33 parts / minute [natural montmorillonite 2 parts (solid content)]. A pellet (water content: 0.3%) of the resin composition was obtained in the same manner except that the set temperature of the portion (vent portion) was changed to 98 ° C., and the same evaluation as in Example 1 was performed. The water content of the resin composition at the time of mixing was 40%.
The moisture content of the pellets before drying was 37%, and the ethylene content of EVOH (A) (29
Mol%), the degree of saponification (99.7 mol%) and the water content (2
(6%) was substituted into 109.7, which satisfied the expression (1).

Example 3 In Example 1, 136 parts / min [98 parts EVOH (solid content)] of EVOH (Α) having a water content of 28% (ethylene content 32 mol%, saponification degree 99.8 mol%) was used. Of natural montmorillonite (B) into Na-type tetrasilicon mica [the degree of swelling (measured according to the standard test method volumetric method of the Japan Bentonite Industry Association) is 97 ml / 2 g]. The dispersion liquid (concentration: 5%) was continuously supplied at a rate of 40 parts / minute [2 parts of Na-type tetrafluorosilicic mica (solid content)], and the set temperature of the intermediate part (vent part) was further reduced. The same procedure was performed except that the temperature was changed to 97 ° C. to obtain pellets (water content: 0.3%) of the resin composition, and the same evaluation as in Example 1 was performed. The water content of the resin composition at the time of mixing was 43%, and the water content of the pellets before drying was 40%.
Met.

Example 4 In Example 1, an 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 resin composition at the time of mixing was 40%, the water content of the pellets before drying was 36%, and EVOH (A) was used in the formula (1) in the text.
Ethylene content (38 mol%), saponification degree (99.8
Mol%) and the water content (25%) are substituted into 101.7.
As a result, the expression (1) was satisfied.

Example 5 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 resin composition at the time of mixing was 42%.
The moisture content of the pellets before drying was 38%, and the ethylene content (32 mol%), the degree of saponification (98 mol%) and the water content (28% ) Was substituted to 81.4, which satisfied the expression (1).

Comparative Example 1 A resin composition pellet (water content 0.3%) was 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.
In addition, the water content of the resin composition at the time of mixing was 64%, and the water content of the pellets before drying was 61%.

Comparative Example 2 A resin composition was obtained in the same manner as in Example 1 except that the natural montmorillonite (B) was directly melt-mixed without forming a dispersion, and the same evaluation as in Example 1 was performed. Thus, a pellet (water content: 0.3%) of the resin composition was obtained, and the same evaluation as in Example 1 was performed. In addition, the water content of the resin composition at the time of mixing was 27%, and the water content of the pellet before drying was 24%.

Table 1 shows the results of Examples and Comparative Examples.

[0057]

[0058]

According to the production method of the present invention, in producing a resin composition containing EVOH (A) and a water-swellable layered inorganic compound (B), EVO having a water content of 40% by weight or less is used.
Since H (A) and the aqueous dispersion of the water-swellable layered inorganic compound (B) are melt-mixed, the obtained resin composition exhibits excellent effects on gas barrier properties and appearance characteristics. The resin composition is provided as a film, sheet, container, or the like, and is useful as various packaging materials such as general foods, retort foods, pharmaceuticals, industrial chemicals, and agricultural chemicals. Particularly useful for containers such as tanks and pesticide bottles.

Continued on the front page F term (reference) 4F070 AA13 AA26 AA28 AC27 AE01 FA03 FA12 FB05 FC05 4J002 BB221 BE031 DE027 DJ006 DJ056 DM006 FD016

Claims (7)

[Claims] 1. A method for producing a resin composition comprising a saponified ethylene-vinyl acetate copolymer (A) and a water-swellable layered inorganic compound (B), wherein ethylene-acetic acid having a water content of 40% by weight or less is used. A method for producing a resin composition, comprising melting and mixing a saponified vinyl copolymer (A) and an aqueous dispersion of a water-swellable layered inorganic compound (B). 2. A saponified ethylene-vinyl acetate copolymer (A) having a water content of 40% by weight or less which satisfies the following formula (1).
The method for producing a resin composition according to claim 1, wherein the resin composition is used. 75 ≦ (0.173 × Sv−20.111) × W + 0.2184 × (Sv−100) ² + 6.5356 × (Sv−100) + 230.67 × exp (−0.0074 × Et) ≦ 135 -(1) However, Et represents ethylene content (mol%), Sv represents saponification degree (mol%), and W represents water content (wt%). 3. The method for producing a resin composition according to claim 1, wherein the water content of the entire resin composition at the time of melt mixing is 20 to 60% 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 40% by weight or less is 10% by weight. A method for producing the composition. 5. The process for producing a resin composition according to claim 1, wherein the concentration of the aqueous dispersion of the water-swellable layered inorganic compound (B) is 0.1 to 10% by weight. 6. A water-swellable layered inorganic compound (B) content of 0.1 to 20 parts by weight based on 100 parts by weight of a saponified ethylene-vinyl acetate copolymer (A). 6. The method for producing the resin composition according to any one of 1 to 5. 7. The method for producing a resin composition according to claim 1, wherein the resin composition is formed into a pellet.