JP2000280326A - Method for molding resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the occurrence of a coloring phenomenon and upgrade the thickness accuracy and the gas barrier properties by making the thickness of a resin composition to be obtained by extruding the composition from the gap of a die slit and a die satisfy specific conditions. SOLUTION: When a resin composition composed mainly of EVOH (an ethylene-polyvinyl acetate copolymer-saponified product) is extruded from a die and molded by melting, the thickness (T1) of the resin composition at the time of extruding it from the gap (T0) of a die slit and the die and casting it by a casting roll, is adjusted so that the thickness (T1) meets the conditions of the respective formulae: 0.05<T0<5.0 and 0.01<(T1/T0)<1.0. In the formulae, however, the units of T0 and T1 are mm. Thus it is possible to upgrade the thickness accuracy and the gas barrier properties without the occurrence of a coloring phenomenon, even when 10-500 ppm sodium in terms of atoms are added to the resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a resin composition such as a saponified ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVOH). The present invention relates to a molding method capable of obtaining a molded article having excellent properties.

[0002]

2. Description of the Related Art Generally, EVOH is excellent in transparency, gas barrier property, fragrance retention, solvent resistance, oil resistance, etc.
Taking advantage of such characteristics, it is used by being formed into films and sheets of food packaging materials, pharmaceutical packaging materials, industrial chemical packaging materials, agricultural chemical packaging materials, and the like, or containers such as bottles. In such forming, usually, melt forming is performed, and by such forming, it is processed into a shape such as a film shape, a sheet shape, a bottle shape, a cup shape, a tube shape, a pipe shape, etc., and is provided for practical use. At the time of molding, if molding is performed for a long time, vertical streaks will occur in the molded product, or the thickness accuracy will be reduced, causing variations, and it will be difficult to obtain a good molded product. As a countermeasure, Japanese Patent Application Laid-Open No. 3-197138 discloses E
With respect to a molded product of the composition (C) comprising the VOH (A) and the thermoplastic resin (B), (A) and (C) were extruded under specific conditions when sodium was contained in the specific amount and extruded under specific conditions. A molded article is described in which the relationship between the molten resin diameter and the relationship between the melt index of (A) and (B) is specified.

[0003]

However, the above-mentioned molded product contains 10 to 500 ppm of sodium in terms of atom.
It is necessary to contain them, and due to such inclusion, there is a possibility that the molded product may be colored by heat or the like at the time of molding, and there is a demand for a method of molding a molded product that is free of coloration and excellent in thickness accuracy and gas barrier properties.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
In view of this situation, as a result of intensive studies, when extruding a resin composition containing EVOH as a main component from a die and performing melt molding, the gap (T0) of the die slit and the resin composition obtained by extrusion from the die are obtained. When the thickness (T1) of the layer satisfies the conditions of the following formulas (1) and (2), the inventors have found that the above object can be achieved, and have completed the present invention. 0.05 <T0 <5.0 (1) 0.01 <(T1 / T0) <1.0 (2) (However, the units of T0 and T1 are both mm.) In the present invention, it has also been found that when the resin composition is a blend of two or more EVOHs or a blend of EVOH and another thermoplastic resin, the effects of the present invention can be more remarkably obtained. .

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
In the molding method of the present invention, when a resin composition containing EVOH as a main component is extruded from a die and melt-molded, the gap (T0) of the die slit and the resin composition when extruded from the die and cast by a casting roll are used. The thickness (T1) of the material layer is adjusted so as to satisfy the conditions of the following formulas (1) and (2). If the conditions are not satisfied, the object of the present invention cannot be achieved. 0.05 <T0 <5.0 (1) 0.01 <(T1 / T0) <1.0 (2) (However, the unit of both T0 and T1 is mm)

That is, in the above formula (1), when the gap (T0) between the die slits is 0.05 mm or less, the pressure in the extruder increases, the extrusion amount decreases, and continuous good extrusion molding is performed. It becomes impossible, and conversely, when it is 5.0 mm or more,
The object of the present invention cannot be achieved because the pressure in the extruder decreases and uniform thickness accuracy cannot be obtained. In addition, in the above formula (2), the gap (T0) of the die slit and the extrusion from the die are performed. T1 / T0 which is the ratio to the thickness (T1) of the layer of the resin composition contained in the molded product obtained by
If the thickness is less than 1.0, the thickness and width of the molded product (such as a film) fluctuate greatly. If the thickness exceeds 1.0, the intended uniform thickness accuracy cannot be obtained, and the object of the present invention cannot be achieved. Preferred conditions of the above formulas (1) and (2) are represented by the following formulas (1 ′) and (2 ′). 0.10 <T0 <4.5 (1 ′) 0.015 <(T1 / T0) <0.95 (2 ′) (However, the unit of both T0 and T1 is mm.) )

Hereinafter, the molding method of the present invention will be described.
This will be described more specifically. The resin composition used in the molding of the present invention is not particularly limited as long as it is mainly composed of EVOH.
When the blend is a blend of VOH or a blend of EVOH and another thermoplastic resin, the effects of the present invention can be more remarkably obtained, which is preferable. These EVOHs are not particularly limited, but have an ethylene content of 20 to 60 mol%.
(More preferably 25 to 55 mol%), those having a saponification degree of 90 mol% or more (more preferably 95 mol% or more) are preferably used,
If the ethylene content is less than 20 mol%, the gas barrier properties and the melt moldability at high humidity decrease, while if it exceeds 60 mol%, sufficient gas barrier properties cannot be obtained, and the saponification degree is 90%.
If it is less than mol%, the gas barrier properties, thermal stability, moisture resistance, etc. decrease, which is not preferred. EVOH has a melt index (MI) (210 ° C., load 2160 g) of 0.5.
-100 g / 10 min (more preferably 1-50 g / 10 min), and when the melt index is smaller than the above range, the inside of the extruder is in a high torque state at the time of molding and extrusion processing becomes difficult. On the other hand, when it is larger than the above range, the mechanical strength of the molded product becomes insufficient and the film-forming property is deteriorated, which is not preferable.

The EVOH is obtained by saponifying an ethylene-vinyl acetate copolymer, and the ethylene-vinyl acetate copolymer can be produced by any known polymerization method, for example, solution polymerization,
It is produced by suspension polymerization, emulsion polymerization, or the like, and saponification of an ethylene-vinyl acetate copolymer can also be performed by a known method.

In the present invention, a copolymerizable ethylenically unsaturated monomer may be copolymerized as long as the effects of the present invention are not impaired. Examples of such a monomer include propylene and 1-butene. , Olefins such as isobutene, acrylic acid, methacrylic acid, crotonic acid, (anhydrous) phthalic acid,
Unsaturated acids such as (anhydride) maleic acid and (anhydride) itaconic acid or salts thereof, mono- or dialkyl esters having 1 to 18 carbon atoms, acrylamide, 1 to 1 carbon atoms
8, acrylamides such as N-alkylacrylamide, N, N-dimethylacrylamide, 2-acrylamidopropanesulfonic acid or a salt thereof, acrylamidopropyldimethylamine or an acid salt thereof or a quaternary salt thereof, methacrylamide, having 1 to 18 carbon atoms Methacrylamides such as N-alkylmethacrylamide, N, N-dimethylmethacrylamide, 2-methacrylamidopropanesulfonic acid or a salt thereof, methacrylamidopropyldimethylamine or an acid salt thereof or a quaternary salt thereof, N-vinylpyrrolidone , N-vinylformamide, N-vinylamides such as N-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, vinyl fluoride, vinylidene fluoride and vinyl bromide And vinylsilanes such as trimethoxyvinylsilane, allyl acetate, allyl chloride, allyl alcohol, dimethylallyl alcohol, trimethyl- (3-acrylamido-3-dimethylpropyl)-
Ammonium chloride, acrylamido-2-methylpropanesulfonic acid and the like.

[0010] When two or more different EVOHs are used as described above, the ethylene content differs by 5 mol% or more and / or the saponification degree is 1 mol%. It is preferable to use a blend of the above different EVOHs, and such a blend is useful because the stretchability at the time of high stretching and the secondary workability such as vacuum pressure forming and deep drawing are improved while maintaining gas barrier properties. It is.

When blending another thermoplastic resin, the resin may be polyolefin resin, polyamide resin, polyester resin, polyvinyl chloride, polyvinylidene chloride, acrylic resin, polystyrene, vinyl ester resin. , Polyester elastomers, polyurethane elastomers, chlorinated polyethylene, chlorinated polypropylene, aromatic and aliphatic polyketones, polyalcohols, etc., preferably linear low density polyethylene, low density polyethylene, medium density polyethylene, high density Polyethylene, ethylene-vinyl acetate copolymer, ionomer, ethylene-propylene copolymer, ethylene-
Acrylic ester copolymer, polypropylene, propylene-α-olefin (C 4-20 α-olefin) copolymer, homo- or copolymer of olefin such as polybutene, polypentene, or homo- or copolymer of these olefins Polyolefin resins such as those obtained by graft-modifying a polymer with an unsaturated carboxylic acid or an ester thereof, polycapramide (nylon-6), poly-ω-aminoheptanoic acid (nylon-7), poly-ω-aminononanoic acid ( Nylon-9), polyundecaneamide (nylon-11), polylauryl lactam (nylon-1
2), polyethylenediamine adipamide (nylon-
2, 6), polytetramethylene adipamide (nylon-
4, 6), polyhexamethylene adipamide (nylon-
6, 6), polyhexamethylene sebacamide (nylon-
6, 10), polyhexamethylene dodecamide (nylon-6, 12), polyoctamethylene adipamide (nylon-8, 6), polydecamethylene adipamide (nylon-10, 8), caprolactam / lauryl lactam Copolymer (nylon-6 / 12), caprolactam / ω-aminononanoic acid copolymer (nylon-6 / 9), caprolactam / hexamethylene diammonium adipate copolymer (nylon-6 / 6, 6), lauryl lactam / Hexamethylenediammonium adipate copolymer (nylon-12 / 6,6), ethylenediamine adipamide /
Hexamethylene diammonium adipate copolymer (nylon-2, 6/6, 6), caprolactam / hexamethylene diammonium adipate / hexamethylene diammonium sebacate copolymer (nylon-6, 6 /
6, 10), ethylene ammonium adipate / hexamethylene diammonium adipate / hexamethylene diammonium sebacate copolymer (nylon-6 / 6,
6/6, 10), a polyamide resin such as polyhexamethylene isophthalamide, polyhexamethylene terephthalamide, hexamethylene isophthalamide / terephthalamide copolymer, or a polyamide resin such as methylenebenzylamine, metaxylenediamine or the like. Examples thereof include those modified with an aromatic amine and metaxylylenediammonium adipate. The blend ratio of EVOH to other thermoplastic resin (EVOH / other thermoplastic resin) is 99/1 to 40/60 by weight. (Furthermore, 97 / 3-4
5/55, particularly preferably 95/5 to 50/50),
If the blend ratio exceeds 99/1, the stretchability and vacuum moldability after molding are inferior, and the retort resistance is reduced when used in retort applications. Conversely, if the blend ratio is less than 40/60, the gas barrier properties are reduced. Not preferred.

In the present invention, the resin composition containing EVOH as a main component as described above is subjected to melt molding. At this time, the resin composition may contain, if necessary,
It is also possible to use additives such as a plasticizer, a heat stabilizer, an ultraviolet absorber, an antioxidant, a coloring agent, an antibacterial agent, and a filler. Furthermore, a hydrotalcite-based compound, a hindered phenol-based compound, a hindered amine-based compound A system heat stabilizer, a metal salt of a higher aliphatic carboxylic acid, and the like can also be added. In molding a resin composition containing EVOH as a main component (hereinafter sometimes simply referred to as a resin composition), usually, melt molding is performed, and such a melt molding method includes an extrusion molding method (T-die). Extrusion) is mainly employed, and this will be specifically described.

The above resin composition is supplied to an extruder (two-screw or single-screw), heated and melted and extruded. The melt molding temperature at this time is selected from a range of about 160 to 300 ° C. You. The heated and melted resin composition has a T
-It is extruded from a die, wound up on a roll or the like and formed into a film of the resin composition. In the present invention, at the time of such melt forming, the gap (T0) of the die slit and the It is necessary to adjust the thickness of the layer of the resin composition when extruded and cast by a casting roll so as to satisfy the conditions of the above formulas (1) and (2). By adjusting the gap (T0) to a range not exceeding 0.05 mm and not exceeding 5.0 mm, the expression (1) can be satisfied. In order to satisfy the expression (2), a die slit is required. The thickness (T1) of the layer of the resin composition in the molded product when extruded from the mold and cast (cooled and fixed) by a casting roll is adjusted to determine the relationship with the gap (T0) of the die slit. The adjustment can be made by adjusting the take-up speed of the casting roll, adjusting the extrusion rate by changing the screw rotation speed, adjusting the extrusion rate by changing the extrusion temperature, adjusting the air gap However, the present invention is not limited to these methods, as appropriate, by appropriately combining a method of performing the method, a method of adjusting the adhesion to the casting roll, and the like. As described above, the molded product of the resin composition melt-extruded so as to satisfy the relations of the formulas (1) and (2) has no coloring, and is excellent in thickness accuracy and gas barrier properties.

The molded product (single-layer film) obtained by the method of the present invention thus obtained can be used for various applications as it is, but is usually laminated with another resin or another substrate as described later. It is often used practically as a body, and is usually laminated through a known adhesive such as an organic titanium compound, an isocyanate compound, a polyester compound, or a polyurethane compound to form a laminate. Of course, it is also possible to laminate two or more such molded products.

Although the method of the present invention has been described above for a single-layer film molded article, the molding method of the present invention is an effective method for producing a molded article of a laminate, and is used together with other resins. Extrusion and extrusion of a resin composition on a substrate can be carried out according to the above. For example, in the case of co-extrusion with a resin composition and another resin by a co-extrusion method, when the resin composition is extruded from a die slit, laminated with another resin layer and cast by a casting roll. The resin composition may be adjusted so as to satisfy the above-mentioned conditions (1) and (2). Also, when the resin composition is extruded on a substrate, the resin composition is extruded from a die slit. Then, when being laminated on a base material and similarly cast by a casting roll, adjustment may be made so as to satisfy the conditions of the above formulas (1) and (2).

In the case of forming a laminate as described above,
In most cases, a laminated product already laminated is extruded from the slit, and only a resin composition containing a saponified ethylene-vinyl acetate copolymer as a main component is hardly extruded from a single die slit. The gap (T0) of the die slit at the time is a value calculated from the gap (amm) of the die slit from which the laminated material is extruded and the volume ratio (b%) of the resin composition when the resin composition passes through the die slit. (A
× b × 0.01).

Such other resins include linear low-density polyethylene, low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ionomer, ethylene-propylene copolymer, ethylene-acrylic acid Ester copolymer, polypropylene, propylene-α-olefin (α having 4 to 20 carbon atoms)
-Olefin) Broadly defined polyolefin-based resins such as copolymers, homo- or copolymers of olefins such as polybutene and polypentene, or those obtained by graft-modifying homo- or copolymers of these olefins with unsaturated carboxylic acids or esters thereof , Polyester, polyamide, copolymerized polyamide, polyvinyl chloride, polyvinylidene chloride, acrylic resin, polystyrene, vinyl ester resin, polyester elastomer, polyurethane elastomer, chlorinated polyethylene, chlorinated polypropylene, aromatic and aliphatic polyketone, poly Alcohol and the like.
EVOH can also be co-extruded. Among the above, polypropylene, polyamide, polyethylene, ethylene-vinyl acetate copolymer, polystyrene, PET, etc., from the viewpoint of easiness of coextrusion film formation and practicality of film physical properties (particularly strength).
PEN is preferably used.

Examples of the substrate include any substrate other than the above-mentioned thermoplastic resin (paper, metal foil, uniaxially or biaxially stretched plastic film or sheet and its metal deposit, woven fabric, nonwoven fabric, metal cotton). Shape, wood, etc.) can be used.

The layer structure of the laminate is the same as the resin for modification of the present invention.
The layer of the EVOH composition in which the composition was blended was a (a₁,
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 a 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_TwoAny combination is possible
A, b are bimetallic, core
(A) -sheath (b) type, core (b) -sheath (a) type, eccentric core sheath
Known composites such as mold, lamination type, multilayer lamination type, split type
Any combination of forms is possible.

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. Stretching may be performed. Stretching as high as possible is preferable in terms of physical properties, and a stretched film, a stretched sheet, a stretched bottle, a stretched container which does not generate pinholes, cracks, stretch unevenness, delamination, etc. during stretching. Etc. are obtained.

As the stretching method, any of a roll stretching method, a tenter stretching method, a tubular stretching method, a stretch blow method, a drawing method such as vacuum forming, pressure forming, vacuum pressure forming, etc., which has a high draw 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 60 to 170 ° C, preferably 80 to
It is selected from a range of about 160 ° C.

After completion of the stretching, it is also preferable to carry out heat setting. Heat setting can be carried out by known means,
80-170 while keeping the stretched film under tension.
The heat treatment is performed at a temperature of 100 ° C., preferably 100 to 160 ° C. for about 2 to 600 seconds. Also, when used for heat shrink packaging of raw meat, processed meat, cheese, etc., the product film is not heat-set after stretching, and the raw meat, processed meat, cheese, etc. are stored in the film, 50-130 ° C, preferably 7
At 0 to 120 ° C, heat treatment is performed for about 2 to 300 seconds,
The film is heat-shrinked and tightly packaged.

The shape of the thus obtained laminate may be any shape, and examples thereof include a film, a sheet, a tape, a bottle, a tube, a cup, a pipe, a filament, and an extrudate having a modified cross section. The obtained laminate may be subjected to heat treatment, cooling, rolling, printing, dry laminating, solution or melt coating, bag making, deep drawing, box processing, tube processing, split processing, etc., as necessary. It can be carried out. The films, sheets, containers and the like obtained as described above are useful as various packaging materials for foods, pharmaceuticals, industrial chemicals, agricultural chemicals and the like.

[0024]

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 [Ethylene content 32 mol%, saponification degree 99.
8 mol%, MI 4 g / 10 min (210 ° C., load 2160
g)] and 65 parts of EVOH [ethylene content: 44 mol%, saponification degree: 95.5 mol%, MI: 3 g / 10 min (same as the left)] were mixed with a T-die. It was supplied to a shaft extruder and melt-extruded under the following film forming conditions.

[Film forming conditions by single screw extruder] Screw inner diameter 40 mm L / D 28 Screw compression ratio 4.0 T-die Coat hanger type Die slit gap (T0) 0.3 mm Die width 450 mm Extrusion temperature C1: 180 ° C C2: 200 ° C C3: 220 ° C C4: 230 ° C D: 200 ° C Extrusion amount 6.8 kg / hr

The resin composition in the form of a film extruded under the above conditions is then wound up on a casting roll having a diameter of 25 cm (drawing speed: 7 m / min, surface temperature: 80 ° C.) and has a thickness (T1) of 0.03 mm. (Monolayer film) was obtained. At this time, T1 / T0 was 0.10, which satisfied the expression (2). The gas barrier properties, coloring properties, and thickness accuracy of the molded articles obtained above were evaluated in the following manner.

(Gas barrier property) Oxygen permeability measuring device (M
OCON “OXTRAN10 / 50”)
The oxygen permeability (cc / m ² · day · atm) per 20 μm thickness was measured under the conditions of 23 ° C. and 50% RH.

(Coloring property) The YI value of the obtained molded product was measured with a color difference meter and evaluated as follows. ○ −−− Less than 15 △ −−− 15 to less than 20 × −−− 20 or more

(Thickness accuracy) The thickness in the width direction of the molded product (0.4 m × 1 m) one hour after the start of molding was measured at intervals of about 5 cm, and the maximum thickness (a), the minimum thickness (b) and the average thickness were measured. (C) was calculated, and the value of (ab) / (c) was calculated and evaluated as follows. ○ −−− <0.15 △ −−− 0.15−0.30 × −−− 0.30 or more

Example 2 EVOH [Ethylene content 32 mol%, saponification degree 99.
7 mol%, MI 3 g / 10 min], 80 parts and a polyolefin resin [“Tuffmer P0180” manufactured by Mitsui Chemicals, density 0.87 g / cm ³ , MI 4.5 g / 10 min (190
20 ° C., load 2160 g)] and supplied to a single-screw extruder equipped with a T-die to perform melt extrusion under the following film forming conditions.

[Film forming conditions by single screw extruder] Screw inner diameter 40 mm L / D 28 Screw compression ratio 4.0 T-die Coat hanger type Die slit gap (T0) 0.2 mm Die width 450 mm Extrusion temperature C1: 180 ° C C2: 200 ° C C3: 220 ° C C4: 230 ° C D: 200 ° C Extrusion amount 6.8 kg / hr

The film-shaped resin composition extruded under the above conditions is then cast on a casting roll having a diameter of 25 cm (take-up speed 10.5 m / min, surface temperature 80 ° C.).
And a molded product (single-layer film) having a thickness (T1) of 0.02 mm was obtained. T1 / T0 at this time is 0.10
Satisfied the expression (2). The molded product obtained above was evaluated in the same manner as in Example 1.

Example 3 In Example 1, as a blend (resin composition),
EVOH [ethylene content 32 mol%, saponification degree 99.
8 mol%, MI 12 g / 10 min (210 ° C., load 216
0 g)] and 35 parts of EVOH [ethylene content 44 mol%, saponification degree 95 mol%, MI 12 g / 10 min (same as the left)] except that the casting roll take-off speed was 14 m / min. Was carried out in the same manner to obtain a molded product (single-layer film) having a thickness (T1) of 0.015 mm. At this time, T1 / T0 was 0.05, which satisfied the expression (2). The molded product obtained above was evaluated in the same manner as in Example 1.

Example 4 In Example 1, as a blend (resin composition),
EVOH [ethylene content 32 mol%, saponification degree 99.
7 mol%, MI 12 g / 10 min (210 ° C., load 216
0 g)] and 70 parts of a polyolefin resin [“Tuffmer P0180” manufactured by Mitsui Chemicals, density 0.87 g / cm ³ ,
MI 4.5 g / 10 min (190 ° C., load 2160 g)]
A molded product (single-layer film) having a thickness (T1) of 0.05 mm was obtained in the same manner except that 30 parts of the blend was used and the take-up speed of the casting roll was 4.2 m / min. At this time, T1 / T0 was 0.17, which satisfied the expression (2). The molded product obtained above was evaluated in the same manner as in Example 1.

Example 5 In Example 1, as a blend (resin composition),
EVOH [ethylene content 32 mol%, saponification degree 99.
7 mol%, MI 4 g / 10 min (210 ° C., load 2160
g)] 90 parts and polyamide resin [nylon 6/6,
6/6, 10] A molded product (single-layer film) having a thickness (T1) of 0.03 mm was obtained in the same manner except that 10 parts of the blend was used. At this time, T1 / T0 was 0.10, which satisfied the expression (2). The molded product obtained above was evaluated in the same manner as in Example 1.

Example 6 A molded product (single-layer film) having a thickness (T1) of 0.02 mm was prepared in the same manner as in Example 1 except that the film forming conditions using a single screw extruder were changed as follows. Obtained. At this time, T1 / T0 was 0.04, which satisfied the expression (2). The molded product obtained above was evaluated in the same manner as in Example 1.

[Film forming conditions by single screw extruder] Screw inner diameter 40 mm L / D 28 Screw compression ratio 4.0 T-die Coat hanger type Die slit gap (T0) 0.5 mm Die width 450 mm Extrusion temperature C1: 180 ° C C2: 200 ° C C3: 220 ° C C4: 230 ° C D: 200 ° C Extrusion amount 7.0 kg / hr

Example 7 In Example 1, the temperature of the casting roll was changed to 60
C. and a take-up speed of 14 m / min. To obtain a molded product (single-layer film) having a thickness (T1) of 0.015 mm. T1 / T0 at this time is 0.05
Satisfied the expression (2). The molded product obtained above was evaluated in the same manner as in Example 1.

Example 8 In Example 1, the extrusion temperature was C1: 200 ° C., and C2:
220 ° C, C3: 240 ° C, C4: 240 ° C, D: 22
The same procedure was performed except that the temperature was 0 ° C., and the thickness (T1) was 0.0
A 3 mm molded product (single-layer film) was obtained. T1 at this time
/ T0 was 0.10, thereby satisfying the expression (2).
The molded product obtained above was evaluated in the same manner as in Example 1.

Example 9 A laminate comprising the blend of Example 1 as an intermediate layer and a polyolefin-based resin layer provided on both outer layers with an adhesive resin layer interposed therebetween was prepared by using five types and five layers of an inflation film forming machine. Molding was carried out under the following conditions under the conditions of the extruder for forming the blend of the intermediate layer.

[Film forming conditions] Screw inner diameter 40 mm L / D 30 Screw compression ratio 3.5 Round-die stacking type Die slit gap (T0) 0.3 mm * [* The above die slit gap (T0) is The value calculated from the actual gap of the die slit (3.0 mm) and the resin volume ratio (10%) of the blend when passing through the die slit] Die diameter 150 mm : 230 ° C J: 220 ° C D: 220 ° C Extrusion rate 7.0 kg / hr

The laminate extruded under the above conditions is then wound up on a casting roll having a diameter of 25 cm (drawing speed 10 m / min, surface temperature 80 ° C.), and a polyolefin resin (LDPE, 35 μm thick) / adhesion Molded resin (modified polyolefin resin, 10 μm thickness) / blend (T1 = 10 μm thickness) / adhesive resin (modified polyolefin resin, 10 μm thickness) / polyolefin resin (LDPE, 35 μm thickness) (laminate) I got
Observing the cross section of the resin composition layer of the obtained laminate with an optical microscope and measuring the thickness (T1) thereof resulted in 0.01 mm. At this time, T1 / T0 was 0.033 and the equation (2) was obtained. I was satisfied. The molded product obtained above was evaluated in the same manner as in Example 1.

Example 10 The blend of Example 1 was formed on an OPP film together with an adhesive resin using a two-layer, two-layer T-die film forming machine under the following film forming conditions. Was.

[Film forming conditions] Screw inner diameter 40 mm L / D 30 Screw compression ratio 3.0 T-die Coat hanger type Die slit gap (T0) 0.5 mm * [* The above die slit gap (T0) is Calculated from the actual die slit gap (1.0 mm) and the resin volume ratio (50%) of the blend when it passes through the die slit] Die width 450 mm Extrusion temperature C1: 180 ° C C2: 220 ° C C3: 240 ° C C4: 240 ° C J: 240 ° C D: 230 ° C Extrusion amount 11 kg / hr

The laminate extruded under the above conditions is then wound on a casting roll having a diameter of 25 cm (having a speed of 50 m / min and a surface temperature of 80 ° C.).
PP film (20 μm thickness) / adhesive resin (modified polyolefin resin, 10 μm thickness) / blend (T1 = 1
(Thickness of 0 μm) (laminate). Observing the cross section of the resin composition layer of the obtained laminate with an optical microscope, the thickness (T
When 1) was measured, it was 0.01 mm. At this time, T1 / T0 was 0.02, which satisfied the expression (2). The molded product obtained above was evaluated in the same manner as in Example 1.

Comparative Example 1 In Example 1, the gap (T 0) of the die slit was set to 0.
The same procedure was performed except that the thickness was set to 03 mm, but the resin pressure became abnormally high and the molding had to be stopped.

Comparative Example 2 In Example 1, the gap (T 0) of the die slit was set to 8.
A molding (single-layer film) having a thickness (T1) of 0.80 mm was obtained in the same manner except that the thickness was set to 00 mm. At this time, T1 / T0 was 0.1, which satisfied the expression (2). The molded product obtained above was evaluated in the same manner as in Example 1.

Comparative Example 3 In Example 1, the gap (T0) of the die slit was set to 3.
A molded product (single-layer film) having a thickness (T1) of 0.015 mm was obtained in the same manner except that the thickness was set to 00 mm. At this time, T1 / T0 was 0.005, which did not satisfy the expression (2). The molded product obtained above was evaluated in the same manner as in Example 1.

Comparative Example 4 In Example 1, the gap (T 0) of the die slit was set to 0.
20 mm, and the rotation speed of the casting roll was set to 0.
The same procedure was followed except that the thickness was 3 m / min, and the thickness (T1)
Of 0.30 mm was obtained. At this time, T1 / T0 was 1.5, which did not satisfy the expression (2). The molded product obtained above was evaluated in the same manner as in Example 1.

Comparative Example 5 The procedure of Comparative Example 2 was repeated except that sodium acetate was added so that the sodium content was 300 pm. The molded product obtained above was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results of the examples and comparative examples.

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[Table 1] Gas barrier property Coloring property Thickness accuracy (cc ・ 20μm / m ²・ atm ・ 24hr) Example 1 0.25 ○ 〃 2 0.28 〃 〃 3 0.27 ○ 〃 4 0.30 ○ ○ 〃 5 0.25 ○ ○ 〃 6 0.25 ○ ○ ７ 7 0.25 ○ ○ ８ 8 0.25 ○ ○ ９ 9 0.30 ○ ○ 〃 10 0.25 ○ ○ Comparative Example 1 Molding is impossible , Not measured 〃 2 0.35 ○ × ３ 3 0.42 ○ × 〃 4 0.38 ○ × ５ 5 0.25 × ×

[0053]

According to the molding method of the present invention, the gap of the die slit and the thickness of the molded product obtained by extruding from the die are adjusted so as to satisfy specific conditions during melt molding.
Excellent in gas barrier properties and thickness accuracy, it is possible to obtain a molded product without coloring, such a molded product, food, pharmaceuticals, agricultural chemicals, films for industrial chemical packaging, sheets, tubes,
Very useful for applications such as bags and containers.

Claims (2)

[Claims] When a resin composition containing a saponified ethylene-vinyl acetate copolymer as a main component is extruded from a die and melt-molded, the resin composition is extruded from a die slit and extruded from the die and cast by a casting roll. When the thickness (T1) of the layer of the resin composition at the time of
And a method of molding a resin composition, wherein the method satisfies the condition of the formula (2). 0.05 <T0 <5.0 (1) 0.01 <(T1 / T0) <1.0 (2) (However, the unit of both T0 and T1 is mm) 2. The method according to claim 1, wherein the resin composition is a blend of two or more saponified ethylene-vinyl acetate copolymers or a blend of a saponified ethylene-vinyl acetate copolymer and another thermoplastic resin. The molding method according to claim 1, characterized in that: