JPH05116259A - Multilayer composing film and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a multilayer composing film having gas barrier properties, flex resistance, etc., and difficult to be yellowed by ultraviolet rays by laminating an ethylene-vinyl alcohol copolymer layer, an adhesive resin layer composed of an ethylene polymer and a plastic film so as to satisfy specific conditions. CONSTITUTION:In a multilayer composing film used as packaging materials for not only food, medicines but also various application, at least one layer of an ethylene-vinyl alcohol copolymer A layer having ethylene content of 20-60mol% and a melt index of etaEg/ten min is provided. At least one layer of an adhesive resin B layer consisting of an ethylene polymer having the melt index of etaAg/ten min and density of 0.9Og/cm<3> or less and a plastic film C are provided, and the B layer and the C layer are laminated so as to be adjoined mutually. When the thickness of the whole layers of the A layer and the B layer is represented by (a) and (b) respectively and thickness per one layer of the B layer by (c), 0.5mum<=a<=20mum, 0.5mum<=b'<=20mum, 1mum<=a+b<=30mum and 0.08<=etaE/etaA<=8 hold.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layered film which has gas barrier properties, flex resistance and boil resistance and is resistant to yellowing by ultraviolet rays.

[0002]

2. Description of the Related Art Conventionally, a biaxially oriented polypropylene film (hereinafter abbreviated as OPP) and a biaxially oriented polyamide film (hereinafter OPA) which are excellent in transparency, mechanical strength, price, etc.
Substrate film such as biaxially stretched polyethylene terephthalate film (hereinafter abbreviated as PET), etc., is laminated with a polyolefin film to impart heat-sealing property, and is used for various purposes such as food and medicine. It is used as a packaging material. However, since these films do not have good gas barrier properties, oxygen entering the bag from the outside causes mold to grow on the contents, volatilizes the contents, oxidizes fats and oils, and changes the flavor. It is easy to do, the storage stability of the contents is poor, and improvement of gas barrier properties is desired.

As a method for improving the gas barrier property, a solution of vinylidene chloride / vinyl chloride copolymer latex or vinylidene chloride / acrylonitrile copolymer is coated on these films (known as PVDC coated film and sold by each company). Film) of ethylene-vinyl alcohol copolymer (hereinafter abbreviated as EVOH) and polyvinyl alcohol (hereinafter abbreviated as PVA)
It is possible by laminating the above film with those films. However, the PVDC-coated film has a yellowish tint as it is, and has a drawback that it is further yellowed by ultraviolet rays.

On the other hand, a laminated product with a film of EVOH or PVA is colorless and transparent and there is no fear of yellowing even with ultraviolet rays, but the price is high and the bending resistance due to the hardness of the film deteriorates. There is a drawback that delamination tends to occur when boiled at high temperature.

Japanese Unexamined Patent Publication (Kokai) No. 51-18775 describes a method for producing a laminated film, which comprises bonding a thin film melt having at least two layers, one layer of which is EVOH, to a base film. Has been. However, in the present invention, as is clear from the examples, the development of the adhesive force between the base film and the coextrusion coating layer,
Although there is a description of applying an isocyanate adhesive (anchor coating agent), there is no description of coextrusion coating without using an anchor coating agent. The use of the anchor coating agent requires a coater and a drier, which not only complicates the machine but also raises the cost, and further has the drawback that it is difficult to increase the speed. Further, an EVO having a ratio of a melting index within a certain range to an adhesive resin made of an ethylene polymer having a density of 0.90 g / cm ↑ 3 or less.
Stacking H to a thickness within a range, and EVO
By reducing both the thickness of the H layer as well as the thickness of the adhesive resin layer, the gelbo flex tester of the multilayer constitution film (US military standard MIL-B-131G, METHO
There is no description about the fact that it is possible to obtain a product whose flex resistance by the device defined by D 2017) is not so different from the flex resistance of the original substrate film. Rather, the publication describes that the heat capacity of the molten resin must be increased in order to develop the adhesive force with the film, and therefore the thickness of the adhesive resin must be increased.

Further, in Japanese Patent Laid-Open No. 52-119690, a tensile elastic modulus of 100 kg / is provided between a paper layer and an EVOH layer.
A laminated material provided with a thermoplastic resin having a size of mm ↑ 2 or less is described. However, according to the invention, the paper layer and the EVO
There is a description about adhesion with the H layer, but no description about a plastic film. In addition, there is no description about stacking without interposing an anchor coating agent and flex resistance.

Further, JP-A-57-182435 discloses a polyolefin layer / a carboxyl group-containing polyolefin or a modified polyolefin layer / EVOH layer / containing a carboxyl group-containing polyolefin with a metal compound.
In the method for producing a laminate comprising an adhesive layer / polyolefin layer, EVOH, modified polyolefin and EVOH,
EVOH and adhesive, or modified polyolefin and EV
A method for producing a laminate is described, which comprises melt-extruding or co-extruding 1 to 3 layers of OH and an adhesive to perform sandwich lamination. However, this publication does not describe coextrusion coating or flex resistance.

[0008] As described above, there is a strong demand in the industry for an inexpensive film which has gas barrier properties, flex resistance and boil resistance and is resistant to yellowing by ultraviolet rays.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to inexpensively supply a multi-layered film which has both gas barrier property and bending resistance and is resistant to yellowing by ultraviolet rays.

[0010]

Means for Solving the Problems The present inventor has conducted earnest research based on the recognition of the above problems, and as a result, found that the ethylene content was 2
0-60 mol%, melt index ηEg / 10 min of ethylene-
At least one vinyl alcohol copolymer (A) layer, melt index ηAg / 10 minutes, density 0.90 g / cm ↑
Adhesive resin consisting of 3 or less ethylene polymer (hereinafter A
Abbreviated as PO) (B) at least one layer and a plastic film (C), the (B) layer is laminated on the plastic film (C) so as to be adjacent, and a multilayer structure satisfying the following formula: The present inventors have found that the film has gas barrier properties, flex resistance and boil resistance, and is resistant to yellowing by ultraviolet rays, and has completed the present invention. 0.5 μm ≦ a ≦ 20 μm (1) 0.5 μm ≦ b ′ ≦ 20 μm (2) 1 μm ≦ a + b ≦ 30 μm (3) 0.08 ≦ ηE / ηA ≦ 8 (4) Formula In the formula, a represents the thickness of all layers of the (A) layer, b represents the thickness of all layers of the (B) layer, and b ′ represents the thickness of each layer of the (B) layer.

Furthermore, the present inventor has provided a plastic film (C) with a molten multilayer body containing at least one layer (A) and at least one layer (B) and satisfying the above formula (4) in a plastic film (C). ) It is possible to obtain a multilayer constitution film at a high speed by coextrusion coating so that the layers are adjacent to each other, and particularly by satisfying the above formulas (1), (2) and (3), a gas barrier at a high speed can be obtained. It has been found that a multi-layered film that has both flexibility, bending resistance, and boil resistance and is resistant to yellowing by ultraviolet rays is obtained.

The present invention will be described in more detail below. In the present invention, EVOH is a known method in which ethylene and vinyl ester are polymerized under pressure in a solvent such as methanol or t-butyl alcohol using a polymerization initiator such as benzoyl peroxide or azobisisobutyronitrile. And then saponified with an acid or alkali catalyst.
Examples of the vinyl ester include various fatty acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl versatate, and vinyl pivalate, vinyl benzoate, etc., but vinyl acetate is preferable in terms of price and the like, and pivalin is preferable in terms of barrier properties. Vinyl acrylate is preferred. The ethylene content of EVOH is 20-60 mol%, preferably 20-50.
The mol% and the degree of saponification of the fatty acid vinyl ester component are 90 mol% or more, preferably 95 mol% or more. When the ethylene content is less than 20 mol%, the gas barrier property at high humidity is deteriorated. On the other hand, if it exceeds 60 mol%, sufficient gas barrier properties cannot be obtained. On the other hand, when the saponification degree is less than 90 mol%, not only the gas barrier property at high humidity decreases but also
The thermal stability of EVOH deteriorates, and gel is likely to occur on the obtained film surface.

Further, EVOH has a smaller amount of propylene, isobutene, 4-methylpentene-1, hexene,
Α-olefins such as octene, unsaturated carboxylic acids such as itaconic acid, methacrylic acid, acrylic acid, maleic acid, salts thereof, partial or complete esters thereof, nitriles thereof, amides thereof, anhydrides thereof, vinyltrimethoxysilane, etc. It does not matter even if it contains a copolymerization component such as a vinylsilane compound, unsaturated sulfonic acid, its salt, alkylthiols, N-vinylpyrrolidone.

The EVOH may be a mixture of two or more kinds of EVOH having different ethylene copolymerization ratios, or a mixture of two or more kinds of EVOH having different degrees of polymerization. Furthermore, the ethylene copolymerization ratio and the degree of polymerization may both be different. Furthermore, it may be a multilayer body of two or more kinds of EVOH.

Further, EVOH contains, in the range that does not impair the present invention, an antioxidant, a colorant, an ultraviolet absorber, a slip agent, an antistatic agent, a plasticizer, a cross-linking agent such as boric acid, an inorganic filler, and an inorganic drying agent. Various additives such as agents and various resins such as polyamide, polyolefin, and super absorbent resin may be blended.

In the present invention, APO contains ethylene as a main component, and propylene, butene, isobutene, 4
7 to 45 kg of one or more α-olefins having 3 or more carbon atoms, preferably 3 to 10 carbon atoms such as methylpentene, hexene and octene, or butadiene
/ Cm ↑ 2 at a temperature of 75 to 100 ° C., using a solution-based liquid phase method, a slurry-based liquid phase method, a fluidized bed gas phase method, a stirred bed gas phase method or the like with a chromium-based catalyst or a Ziegler catalyst. The copolymer obtained by polymerization, or ethylene as a main component, vinyl acetate, acrylic acid ester, methacrylic acid ester, etc., at a pressure of 2000 to 3000 kg / cm ↑ 2 in the same manner as in ordinary polymerization of low density polyethylene, 120-2
A copolymer obtained by polymerization using a fluidized bed gas phase method, a stirred bed gas phase method or the like at a temperature of 50 ° C. with a radical catalyst is used to prepare maleic anhydride, maleic acid, itaconic anhydride, itaconic acid, acrylic acid. An unsaturated carboxylic acid such as acid or methacrylic acid or an anhydride is added to a radical polymerization initiator (for example, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane-3) in a polymerization tank or an extruder. 0.1% by weight) was used for graft modification at 200 to 240 ° C. The ethylene copolymerization ratio of the copolymer is preferably 10 to 40 mol%, and the degree of graft modification of the unsaturated carboxylic acid or its anhydride is preferably 0.005 to 7% by weight with respect to the copolymer. Is. Among the above-mentioned copolymers, preferable ones are ethylene and propylene, butene or 4-methylpentene, and one or more kinds of α-
Copolymer with olefin (copolymerization ratio ethylene 60-9
0 mol%, α-olefin 10 to 40 mol%, preferably ethylene 70 to 85 mol%, α-olefin 15 to 3
0 mol%) is graft-modified with maleic anhydride (modification degree 0.005 to 7% by weight, preferably 0.02 to 5% by weight), and has a density of 0.90 g / cm ↑ 3 or less,
It is preferably 0.89 g / cm 3 or less. When the density exceeds 0.90 g / cm ↑ 3, the adhesiveness with the plastic film (C) decreases during coextrusion coating, and an anchor coating agent is required. Even when EVOH is coextrusion coated so as to come into contact with a plastic film without using an anchor coating agent, sufficient adhesion with the plastic film cannot be obtained. Here, the density is a value determined according to ASTM-D-1505.

In addition, APO may be an antioxidant, a coloring agent, an ultraviolet absorber, a slip agent,
You may mix | blend various additives, such as an antistatic agent, a plasticizer, a crosslinking agent, an inorganic filler, and an inorganic drying agent, and various resins, such as a thermoplastic resin.

In the present invention, the total thickness of the EVOH layer is a μm, and the total thickness of the APO layer is b μm.
When the thickness per layer of the (B) layer is b'μm, it is important to satisfy the following formula: 0.5 μm ≦ a ≦ 20 μm (1) 0.5 μm ≦ b '≦ 20 μm (2) 1 μm ≦ a + b ≦ 30 μm (3) Preferably, it is as follows. 0.5 μm ≦ a ≦ 15 μm (5) 0.5 μm ≦ b ′ ≦ 15 μm (6) 1 μm ≦ a + b ≦ 25 μm (7) More preferably, it is as follows. 1 μm ≦ a ≦ 10 μm (8) 1 μm ≦ b ′ ≦ 10 μm (9) 2 μm ≦ a + b ≦ 20 μm (10)

The total thickness (a) of the EVOH layer is 0.5
If it is less than μm, sufficient gas barrier properties cannot be obtained. On the other hand, when it exceeds 20 μm, the flex resistance of the multilayer constitution film is deteriorated. Also, the thickness per one layer of the APO layer (b ')
However, if it is less than 0.5 μm, a sufficient interlayer adhesive force cannot be obtained without the anchor coating agent. On the other hand, when the thickness exceeds 20 μm, not only the transparency of the multilayer constitution film is deteriorated but also the economical efficiency is deteriorated. Furthermore, the thickness of all EVOH layers and A
If the total thickness (a + b) of all layers of the PO layer is less than 1 μm, the stability of the molten multilayer body is poor and film breakage easily occurs.
On the other hand, when it exceeds 30 μm, not only the flex resistance of the multilayer constitution film is deteriorated but also the economical efficiency is deteriorated. By satisfying all such conditions, it becomes possible to obtain a multi-layered film having productivity, economy, strength and the like.

In order to obtain a thin co-extrusion coating film having a uniform thickness distribution in the width direction of each layer and all layers as described above, the melting index (JIS) of EVOH (in the case where EVOH is a blend) is measured. According to K 7210, the weight discharged from a nozzle having a radius of 1 mm at a temperature of 230 ° C. and a load of 2160 g in 10 minutes (hereinafter abbreviated as MFR) is η.
Eg / 10 minutes, similarly, when the MFR of APO is ηAg / 10 minutes, 0.08 ≦ ηE / ηA ≦ 8, preferably 0.
1 ≦ ηE / ηA ≦ 5, more preferably 0.2 ≦ ηE / ηA
It is important to select from the range of ≦ 3. When ηE / ηA is less than 0.08 or exceeds 8, the coextrusion coating film may have thickness unevenness in the width direction, or wood grain pattern or satin finish may occur. , It has a poor appearance and cannot be thinned. Furthermore, it is difficult to uniformly thin each layer in a device of a different system such as a dual slot die. Further, a pin and a vane are provided for each flow path of EVOH (A) and APO (B),
It is desirable to use a feed block manufactured by Krollen Co., which has excellent thickness controllability. By adopting such conditions, it is possible to obtain a multi-layered film having uniform thickness of each layer at high speed.

In the present invention, the plastic film (C) is not particularly limited, but a biaxially stretched polypropylene film having a stretching area ratio of 10 times or more, or a biaxially stretched or rolled high density polyethylene film having a stretching area ratio of 4 times or more. Or a biaxially stretched polyamide film having a stretched area ratio of 4 times or more, or a biaxially stretched polyethylene terephthalate film having a stretched area ratio of 4 times or more has printability,
It is suitable in terms of practical strength and economy. Further, these plastic films may be printed or may be plain.

In the present invention, the flex resistance (the number of times one pinhole is generated by bending at 20 ° C. in a gelbo flex tester, d) of the multilayer constitution film obtained by coextrusion coating is the plastic film (C )
0.5 times or more of the bending resistance (the same number of times c), that is, 0.
It is desirable to satisfy 5 × c ≦ d, and preferably 0.
It is preferably 7 times or more, more preferably 0.8 times or more.
In general, those having good flex resistance (the ones having a large number of times) are less likely to cause pinholes due to vibration during transportation or the like, but when the films are laminated, unfortunately the flex resistance tends to deteriorate.

In the present invention, the coextrusion-coated multi-layered film may be used as it is as a packaging material, but it may be difficult to obtain sufficient heat-sealing strength. Therefore, JIS rather than plastic film (C)
Laminated on the opposite side of the (C) layer (which may be printed) is a heat seal layer made of plastic whose Vicat softening point measured by the method specified in K 7206 is lower than 15 ° C, preferably lower than 25 ° C. Do it again, EVOH
A heat seal layer made of plastic having a lower Vicat softening point than (A) is laminated on the (C) layer side (which may be printed), or a plastic film (C)
Sufficient heat-sealing strength can only be obtained by laminating a heat-sealing layer made of plastic whose Vicat softening point is lower than that of both EVOH (A) and EVOH (A) on both sides (may be printed). And a packaging material having good heat sealability can be obtained. The thickness of the heat seal layer is appropriately selected according to the weight of the content, but is generally 20 to 150 μm.

As a method for laminating the heat seal layer, a film made of plastic having a lower Vicat softening point than the plastic film (C) or EVOH (A), or a multi-layer having a low Vicat softening point on at least the heat sealed surface Dry lamination of a plastic film and the above-mentioned multilayer constitution film of the present invention, or
A method of polysand laminating, or finally extruding and laminating a plastic having a low Vicat softening point onto the multilayer constitution film of the present invention, or at least a molten multi-layer body having a low Vicat softening point of the surface to be heat-sealed, Examples thereof include a method of co-extruding and laminating a multi-layered film.

Examples of the plastic having a low Vicat softening point used for the heat seal layer include polypropylene, polyethylene, polyester, polyamide, polyacrylonitrile and the like, which may be used alone or by blending two or more kinds of plastics. You may use. Further, these plastics include various kinds of antioxidants, coloring agents, ultraviolet absorbers, slip agents, antistatic agents, plasticizers, cross-linking agents, inorganic fillers, inorganic desiccants, etc. within the range that does not hinder the present invention. You may mix | blend various resins, such as an additive and a thermoplastic resin.

The polypropylene used for the heat-sealing layer is a homopolymer of propylene and ethylene, butene-1,5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 1, containing propylene as a main component. Examples thereof include copolymers with 4-hexadiene and the like, and those graft-modified with a carboxylic acid such as maleic anhydride.

The polyethylene used for the heat-sealing layer is a homopolymer of ethylene, such as high density polyethylene, medium density polyethylene, low density polyethylene, and propylene, butene-1,4-methylpentene containing ethylene as a main component. -1,1-hexene, 1-octene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, vinyl acetate, butyl acetate, methyl acrylate, ethyl acrylate, acrylic acid, methyl methacrylate, methacrylic acid Examples thereof include copolymers with ethyl, methacrylic acid and the like. The copolymer with acrylic acid or methacrylic acid among the copolymers may be cross-linked with sodium, zinc, aluminum or the like, and the copolymer with vinyl acetate is a part of the vinyl acetate component or All may be saponified. The polyethylene may be graft-modified with a carboxylic acid such as maleic anhydride.

Further, as the polyester used for the heat seal layer, ethylene glycol, diethylene glycol, trimethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, 4,4'-
Polyhydric alcohol components such as dihydroxydiphenyl-2,2-propane, glycerin, and pentaerythritol,
Parahydroxybenzoic acid, δ-valerolactone, ε-caprolactone, hydroxycarboxylic acid components such as tartaric acid, and terephthalic acid, isophthalic acid, various naphthalene dicarboxylic acids, azelaic acid, sebacic acid, pimelic acid, adipic acid, glutaric acid, amber Examples thereof include polyesters and the like obtained from polyvalent carboxylic acids such as acids and their ester components as raw materials.

As the polyamide used in the heat-sealing layer, diamine components such as hexamethylenediamine, piperazine, tetramethylenediamine, ethylenediamine and metaxylylenediamine, δ-valerolactam, ε-caprolactam and ω-laurolactam. , Ω
-Aminocarboxylic acid components such as aminoundecanoic acid and ω-aminododecanoic acid, and various polyvalents such as naphthalene dicarboxylic acid, terephthalic acid, isophthalic acid, azelaic acid, sebacic acid, pimelic acid, adipic acid, glutaric acid and succinic acid Examples thereof include polyamides obtained from a carboxylic acid component as a raw material.

Further, examples of the polyacrylonitrile used in the heat-sealing layer include copolymers containing acrylonitrile as a main component and styrene, methyl methacrylate, methyl acrylate, ethyl methacrylate, ethyl acrylate, butadiene and the like. Be done.

The multilayer constitution of the multilayer constitution film of the present invention includes C / B / A, C / B / A / B, C / B / A / B /
A typical example is A, and a film having the above-mentioned layer structure and the above-mentioned heat-sealing layer provided on one side or both sides thereof. The multi-layered film thus obtained is useful as various packaging materials (foods, medicines), and is particularly effective for bag-in-boxes and the like which require bending resistance.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. All parts and% are based on weight unless otherwise specified.

[0033]

【Example】

Example 1 Biaxially oriented polypropylene film (OP) having a thickness of 20 μm
P) (stretching area magnification 10 times) (Tokyo Cellophane Paper Co., Ltd.)
("Tocello OP U-1 Vicat softening point 150 ° C")
In (C), ethylene content 27 melted to 250 ° C.
Mol%, saponification degree of vinyl acetate component 99.6 mol%, MF
RVO 7.0g / 10min EVO with Vicat softening point 180 ° C
H (A), melted at 220 ° C., density 0.88 g /
cm ↑ 3, MFR 8.0 g / 10 min Copolymer with propylene (25 mol%) containing ethylene (75 mol%) as a main component, and maleic anhydride (0.1 wt%) grafted APO ( B) and, using a feed block manufactured by Krollen, at a speed of 50 m / min, the APO (B) layer is OP
Co-extrusion coating was performed so as to be in contact with P (C) to obtain a multilayer constitution film in which each of the (A) layer and the (B) layer had a thickness of 2 μm.

Using a Gelbo Flex Tester (manufactured by Rigaku Kogyo Co., Ltd.), the number of times one pinhole was generated by bending at 20 ° C. (a film of A-4 size was bent a certain number of times, The number of pinholes generated in the film is measured, a correlation diagram between the number of flexures and the number of pinholes is created, and the number of flexures in which one pinhole is generated is determined from the regression curve. Hereinafter, abbreviated as N ↓ P = 1) The obtained multilayer constitution film was good at 2200 times as compared with 1800 times by OPP. In addition, the laminating strength of OPP and APO and APO and EVOH (T type peeling, speed 250 mm / min, sample width 15 mm) causes the material destruction of the coating film,
It was too big to measure.

Adhesive for dry lamination (Takelac A-385 and Takenate A-, manufactured by Takeda Pharmaceutical Co., Ltd.)
50 is mixed at a ratio of 6: 1) on the EVOH surface of the obtained multilayer constitution film as a solid content of 3 g / m ↑ 2,
After evaporating the solvent, a low-density polyethylene film having a thickness of 60 μm (manufactured by Aicello Chemical Co., Ltd., Suzuron L S-
210, Vicat softening point 95 which is abbreviated as LDPE hereinafter
C.) and a speed of 50 m / min. The gas barrier property of this film is 2 cc / m ↑ 2 ・ day ・ atm (OX-TRAN 10 / 50A manufactured by Modern Control Co., Ltd.)
Was measured at a temperature of 20 ° C. and a humidity of 65%).

The film was sealed at a side seal temperature of 155
℃, bottom sealing temperature 160 ℃, speed 60 bags / min, vertical 23
A bag was made in 0 mm and 150 mm in width, 100 ml of water was added, and the bag was sealed with an impulse sealer to obtain a 4-sided bag. Even when this product was boiled at 98 ° C. for 30 minutes, no change in appearance such as delamination was observed, and it had good boil resistance. The film did not yellow even when exposed to a fluorescent lamp for one month.

Comparative Example 1 In Example 1, a density of 0.8 was obtained by melting at 220 ° C.
8 g / cm ↑ 3, MFR 8.0 g / 10 min Instead of APO which is composed of ethylene as a main component, a linear low density of 0.91 g / cm ↑ 3 and MFR 12 g / 10 min, which is melted at 250 ° C. Polyethylene {Ethylene as the main component (95
Mol%) 4-methyl-1-pentene (5 mol%)
The same procedure as in Example 1 was carried out except that APO consisting of a copolymer obtained by grafting maleic anhydride (0.07% by weight) on the copolymer was used.

The laminating strength of OPP and APO is 2
It was 0 g / 15 mm or less and did not adhere at all.

Comparative Example 2 Biaxially stretched polyethylene terephthalate (PET) having a thickness of 12 μm (stretching area magnification 9 times) (Dia foil Co., Ltd.)
H-500, Vicat softening point 240 ° C.), an adhesive for dry laminating (Takelac A-385 and Takenate A-50 manufactured by Takeda Pharmaceutical Co., Ltd. were mixed at a ratio of 6: 1) as a solid content of 3 g / After applying m ↑ 2 and evaporating the solvent at 70 ° C., it was laminated with a biaxially stretched EVOH film having a thickness of 15 μm (EF-XL manufactured by Kuraray Co., Ltd.) at a speed of 20 m / min. Further, 3 g / m ↑ 2 of solid adhesive was applied as a solid content, the solvent was evaporated, and then laminated with LDPE having a thickness of 60 μm at a speed of 20 m / min.
Aged at ℃ for 3 days. The obtained film was used in Example 1.
A bag was made in the same manner as above and subjected to a boil test at 98 ° C. for 30 minutes, but delamination occurred on the entire surface.

Comparative Example 3 An OPP (Tocello OPU-1 manufactured by Tokyo Cellophane Paper Co., Ltd.) having a thickness of 20 μm was coated with an anchor coating agent (AD-503 / CAT-10A-50 manufactured by Toyo Morton Co., Ltd., 100: 4). 0.5) as a solid content
/ M ↑ 2, the solvent was evaporated, and then LDPE with a thickness of 60 μm was melted at 250 ° C., and the density was 0.92 g /
cm ↑ 3, AFR composed mainly of low-density polyethylene of MFR 2.0 g / 10 min, was melted at 250 ° C., ethylene content 32 mol%, saponification degree of vinyl acetate component 99.5 mol%, MFR 20 g / 10 minutes, EVOH having a Vicat softening point of 170 ° C., using a feed block manufactured by Krollen Co., Ltd., each having a thickness of 10 μm and a speed of 15 m /
In minutes, sandwich lamination was performed so that EVOH was in contact with OPP. The obtained film was not only poor in appearance due to the wood grain pattern due to the unevenness of the thickness of each layer, but the N ↓ P = 1 was 700 times and the OPP was 1800.
It was much worse than the times.

Example 2 In Example 1, the OPP having a thickness of 20 μm was added to 250 ° C.
Ethylene content 27 mol%, saponification degree of vinyl acetate component 99.6 mol%, MFR 7.0 g / 10
Min, EVOH (A) with a Vicat softening point of 145 ° C., 22
Melted at 0 ° C, density 0.88g / cm ↑ 3, MFR
APO obtained by grafting maleic anhydride onto a copolymer of propylene containing 8.0 g / 10 min of ethylene as a main component.
(B) and (B) were laminated using a feed block manufactured by Cloren Co., Ltd., and APO was 0 at a speed of 50 μm / min at 2 μm.
Instead of coextrusion coating to contact PP, OPA with a thickness of 15 μm (drawing area magnification 9 times)
("Boneel R" manufactured by Kojin Co., Ltd., Vicat softening point 205
C.) (C), melted at 250.degree. C., ethylene content 47 mol%, saponification degree of vinyl acetate component 99.5 mol%,
MFR 25g / 10min EVOH (A), melted at 240 ° C, density 0.89g / cm ↑ 3, MFR 16g
APO (B) obtained by grafting maleic anhydride (0.2% by weight) on a copolymer with propylene (20% by mole) containing ethylene (80% by mole) as a main component for 10 minutes, 120m / speed using feed block
Example 1 except that co-extrusion coating was performed such that APO (B) was in contact with OPP (C) in minutes to obtain a multilayer constitution film in which the thickness of each of the (A) layer and the (B) layer was 4 μm. It was carried out according to. N ↓ P = 1, OPA is 420
Compared to 0 times, the obtained multilayer constitution film was 4500 times, which was good, and the gas barrier property was 13 cc / m ↑ 2 · d.
It was as good as ay · atm. Furthermore, this laminated film is laminated with LDPE film at 98 ° C.
After 30 minutes of boiling test, no delamination occurred. The film did not yellow even when exposed to a fluorescent lamp for one month.

Comparative Example 4 In Example 1, the thickness of EVOH (A) was 4 μm and A
Example 1 except that the thickness of the PO (B) layer was 40 μm
A multilayer constitution film was obtained under the same conditions as described above. The obtained multilayer constitution film had a streak pattern due to the heat loss of OPP and had a poor appearance. Boil test for bag-making products is APO
Delamination due to layer disturbance was seen.

Example 3 In Example 1, an OPP having a thickness of 20 μm was added to 250 ° C.
Ethylene content 27 mol%, saponification degree of vinyl acetate component 99.6 mol%, MFR 7.0 g / 10
Min, EVOH (A) with a Vicat softening point of 145 ° C., 22
Melted at 0 ° C, density 0.88g / cm ↑ 3, MFR
APO obtained by grafting maleic anhydride onto a copolymer of propylene containing 8.0 g / 10 min of ethylene as a main component.
(B) and (B) were laminated using a feed block manufactured by Cloren Co., Ltd., and APO was 0 at a speed of 50 μm / min at 2 μm.
Instead of performing co-extrusion coating so as to come into contact with PP, OPA having a thickness of 15 μm (“Bonil R” manufactured by Kojin Co., Ltd., Vicat softening point 205 ° C.) (C) was melted at 250 ° C., Ethylene content 47 mol%, saponification degree of vinyl acetate component 99.5 mol%, MFR 25 g / 10 min E
VOH (A), melted at 240 ° C., density 0.90
g / cm ↑ 3, MFR 12 g / 10 min Ethylene main component (82 mol%) butene (18 mol%) copolymer grafted with maleic anhydride (0.26 wt%) APO (B ) And APO (B) are OPP at a speed of 80 m / min using a feed block manufactured by Krollen.
Co-extrusion coating was carried out so as to be in contact with (C), and the same procedure as in Example 1 was carried out except that a multi-layer constitution film having a thickness of each of the (A) layer and the (B) layer of 4 μm was obtained. N
↓ P = 1 was 4100 times in OPA and 4100 times in the obtained multilayer constitution film, and the gas barrier property was 13 cc / m ↑ 2 · day · atm. Further, a LDPE film laminated on this multilayer film was subjected to a boil test at 98 ° C. for 30 minutes, but no delamination occurred. The film did not yellow even when exposed to a fluorescent lamp for one month.

[0044]

[Table 1]

[0045]

[Table 2]

[0046]

[Table 3]

[0047]

As described above, according to the present invention, a multi-layered film having gas barrier properties, flex resistance and boil resistance, and which is resistant to yellowing by ultraviolet rays can be obtained.

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Claims (7)

[Claims] 1. An ethylene-vinyl alcohol copolymer (A) layer having an ethylene content of 20 to 60 mol% and a melting index of ηEg / 10, and a melting index of ηAg / 1.
0 minutes, at least one layer of an adhesive resin (B) made of an ethylene polymer having a density of 0.90 g / cm ↑ 3 or less and a plastic film (C), and a layer (B) and a layer (C).
A multilayer constitution film in which the layers are laminated so as to be adjacent to each other and satisfy the following formula. 0.5 μm ≦ a ≦ 20 μm (1) 0.5 μm ≦ b ′ ≦ 20 μm (2) 1 μm ≦ a + b ≦ 30 μm (3) 0.08 ≦ ηE / ηA ≦ 8 (4) Formula In the formula, a represents the thickness of all layers of the (A) layer, b represents the thickness of all layers of the (B) layer, and b ′ represents the thickness of each layer of the (B) layer. 2. The plastic film (C) is a gelbo flex tester, and the number of times that one pinhole is generated by bending at 20 ° C. is c times, and the obtained multilayer constitution film is bent by a gelbo flex tester. Therefore, when the number of occurrences of one pinhole is d times, 0.5 × c ≦ d
The multilayer constitution film according to claim 1, which satisfies the following formula. 3. A heat-sealing layer made of plastic having a lower Vicat softening point than that of the plastic film (C) is laminated on the opposite side of the plastic film (C), or the ethylene-vinyl alcohol copolymer (A) is used.
A heat-sealing layer made of plastic having a lower Vicat softening point is laminated on the plastic film (C) layer side, or the plastic film (C) and ethylene-
The multilayer constitution film according to any one of claims 1 and 2, wherein heat sealing layers made of a plastic having a lower Vicat softening point than both of the vinyl alcohol copolymer (A) are laminated on both sides. 4. An ethylene-vinyl alcohol copolymer (A) layer having an ethylene content of 20 to 60 mol% and a melting index ηEg / 10, and a melting index ηAg / 1.
0 minutes, at least one adhesive resin (B) layer made of an ethylene polymer having a density of 0.90 g / cm ↑ 3 or less,
A method for producing a multilayer-structured film, characterized in that a molten multilayer body satisfying the relationship of 0.08 ≦ ηE / ηA ≦ 8 is coextruded and coated on a plastic film (C) so that the layer (B) is adjacent to the plastic film (C). 5. An ethylene-vinyl alcohol copolymer (A) layer having an ethylene content of 20 to 60 mol% and a melting index ηEg / 10 min, and a melting index ηAg / 1.
A molten multilayer body containing at least one adhesive resin (B) layer made of an ethylene polymer having a density of 0 minutes and a density of 0.90 g / cm ↑ 3 or less is adjacent to a plastic film (C) with a layer (B). Co-extrusion coating as described above, the method for producing a multilayer component film according to any one of claims 1 to 2. 6. The plastic film (C) is a gelbo flex tester, and the number of times that one pinhole is generated by bending at 20 ° C. is c times, and the obtained multilayer constitution film is bent by a gelbo flex tester. Therefore, when the number of occurrences of one pinhole is d times, 0.5 × c ≦ d
The method for producing a multilayer constitution film according to any one of claims 4 to 5, which satisfies the following formula. 7. A heat-sealing layer made of plastic having a lower Vicat softening point than that of the plastic film (C) is laminated on the opposite side of the plastic film (C), or an ethylene-vinyl alcohol copolymer (A) is used.
A heat-sealing layer made of plastic having a lower Vicat softening point is laminated on the plastic film (C) layer side, or the plastic film (C) and ethylene-
The method for producing a multilayer-structured film according to any one of claims 4 to 5, wherein heat-sealing layers made of plastic having a lower Vicat softening point than both of the vinyl alcohol copolymer (A) are laminated on both sides.