JP2000202969A - Gas barrier film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas barrier film excellent in transparency, gas barrier properties and adhesiveness, not losing excellent gas barrier properties even after boiling treatment or retorting treatment, having good bending resistance and strength characteristics sufficiently withstanding even a falling impact and capable of being produced in an industrially advantageous manner. SOLUTION: A gas barrier film is constituted by forming an inorg. vapor deposition layer on one of or both of the A-layers of a substrate polyamide film having layered constitution of A-layer/B-layer or A-layer/B-layer/A-layer. Wherein the A-layer is based on an aliphatic polyamide resin (X) and the B- layer is based on an aliphatic polyamide resin (Y). In this case, a ratio (a)/(b) of the water absorption (a) of the aliphatic polyamide resin (X) and the water absorption (b) of the aliphatic polyamide resin (Y) is set to 0.5 or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a gas barrier property and a moisture-proof property which are important properties in packaging films for fresh foods, processed foods, medical products, medical equipment, electronic parts and the like, as well as transparency and handling. The present invention relates to a gas barrier film or sheet having excellent properties (hereinafter collectively referred to as a gas barrier film).

[0002]

2. Description of the Related Art In recent years, food packaging has been drastically changed due to changes in food distribution and dietary habits, and the characteristics required for packaging films and sheets (hereinafter collectively referred to as films) are increasing. It's getting tougher.

[0003] Temperature, moisture, oxygen,
Deterioration of the quality of products due to ultraviolet rays and the influence of microorganisms such as bacteria and mold is a serious problem not only in terms of sales but also in terms of food hygiene. As a method of preventing such quality deterioration, antioxidants and preservatives have been added directly to foods in the past, but in recent years, regulations on food additives have become stricter from the standpoint of consumer protection. Is required to be reduced or not added. Under such circumstances, there has been an increasing demand for packaging films that have low gas and moisture permeability and do not cause deterioration in quality as food even by freezing, boiling, retorting, and the like.

[0004] That is, in the packaging of fish meat, animal meat, shellfish and the like, it is important to suppress the oxidation and deterioration of proteins and oils and fats, and to maintain the taste and freshness. It is desirable to use a material to block air permeation. In addition, packaging with good gas barrier properties retains the fragrance of the contents and prevents the permeation of moisture. Solidification is suppressed, and fresh flavor during packaging can be maintained for a long time.

For these reasons, kneaded products such as kamaboko, dairy products such as butter and cheese, miso, tea, coffee,
In packaging films for confectionery such as ham and sausage, instant food, castella, biscuit, etc., gas barrier properties and moisture resistance are extremely important properties. These characteristics are not limited to the film for food packaging, but are also extremely important as a packaging film for medical products that need to be handled under aseptic conditions or electronic components that require rust prevention.

As a film having excellent gas barrier properties,
Known are those in which a metal foil such as aluminum is laminated on a plastic film, and those in which vinylidene chloride or an ethylene vinyl alcohol copolymer is coated.

In actual use, a sealant layer is provided on the above-mentioned gas barrier film by a dry lamination method via a printing layer and an adhesive, or a sealant layer is provided by an extrusion lamination method. After forming a laminate, filling the contents with the bag and filling the contents, the opening is heat-sealed, for example, a seasoning such as miso or soy sauce, or a water-containing food or chemical such as soup or retort food. It is packaged and provided to general consumers.

The following problems have been pointed out in the conventional gas barrier laminated films as described above. Although a metal foil laminated as a gas barrier layer is excellent in economy and gas barrier properties, it is opaque, so that its contents cannot be seen when packaged, and does not transmit microwaves, so that it cannot be processed by a microwave oven. Also,
Those coated with vinylidene chloride or ethylene vinyl alcohol copolymer do not have sufficient gas barrier properties against water vapor, oxygen and the like, and the performance is particularly deteriorated by high-temperature treatment. In addition, there is a concern that vinylidene chloride may cause air pollution due to generation of chlorine gas at the time of incineration.

In order to solve such a problem, a gas barrier film having an inorganic vapor-deposited layer made of silicon oxide, aluminum oxide or the like as a gas barrier layer has been proposed.
As a substrate film on which silicon oxide, aluminum oxide, or the like is deposited, a polyester film (PET) having good dimensional stability has been used.

The layer structure is usually a laminated structure such as PET / deposited layer / adhesive layer / PET / adhesive layer / unstretched polypropylene (CPP). But,
In such a film having a laminated structure, insufficient strength against a drop impact becomes a problem. Therefore, in order to improve the strength against drop impact, a gas barrier laminated film in which stretched nylon having excellent strength is laminated has been proposed. For example,
In the case of a laminated structure such as PET / deposited layer / adhesive layer / stretched nylon (ONY) / adhesive layer / unstretched polypropylene (CPP), the strength against drop impact is improved as compared with the previous case, but the stretched nylon Due to the shrinkage, there arises a problem that the gas barrier property after the boil treatment or the retort treatment is inferior or the cost is increased.

[0011] Therefore, a film laminated with nylon having a reduced shrinkage ratio during hot water treatment (Japanese Patent Laid-Open No. 7-2765).
No. 71) has been proposed. However, the manufacturing process and the process of transport and storage become complicated, so that economic efficiency is inferior, and the thickness of the film makes handling difficult, which is not practical.

[0012] A gas barrier film using a nylon film as a deposition substrate was also studied. However, the nylon film has a large dimensional change due to moisture absorption and heating, so that the gas barrier property is unstable. In particular, a gas barrier film after boil treatment or retort treatment is used. There is a problem that the performance is poor.

Therefore, as a measure for improving the gas barrier property, a laminated film using stretched nylon, whose shrinkage rate has been reduced in advance by heat treatment, as a deposition base material (Japanese Patent Publication No. 7-126).
No. 49) has been proposed. However, the manufacturing process and the transportation and storage processes become complicated, which is not practical. In addition, nylon having a small shrinkage ratio during high-temperature treatment (in Japanese Patent Publication No. Hei 7-12649, the sum of absolute values of dimensional changes in the vertical and horizontal directions when heated at 120 ° C. for 5 minutes is 2% or less). Even if it is, the boil treatment which is a high-temperature hot water treatment cannot maintain excellent gas barrier properties.

Further, when a nylon film is used as the vapor deposition base material, if water enters between the nylon film and the inorganic vapor deposition layer, the adhesive force between the nylon film and the inorganic vapor deposition layer is remarkably reduced, and the nylon film is used as a packaging bag. It is considered that this sometimes causes not only bag breakage but also a decrease in gas barrier properties. Further, in order to improve the strength against drop impact and bending, a polyamide elastomer is added to the nylon film, but there is a problem that the cost is high.

As described above, a gas barrier film having a laminated structure provided with an inorganic vapor-deposited layer of silicon oxide, aluminum oxide, or the like has disadvantages in that the strength is not always sufficient and the cost is increased. In addition, it is pointed out that a gas barrier film using a nylon film as a deposition base material has a deteriorated gas barrier property due to boiling treatment or retort treatment.

In addition, Japanese Patent Publication No. 51-48511 discloses a gas barrier film that is transparent, allows the contents to be seen through, and is applicable to a microwave oven. A gas barrier film on which SiO ₂ is deposited has been proposed. However,
SiOx system with good gas barrier properties (x = 1.3 to 1.
8) The deposited film has a slightly brown color, and cannot be said to be sufficient in quality as a transparent gas barrier film.

Japanese Patent Application Laid-Open No. 62-101428 discloses a device provided with an inorganic vapor-deposited layer mainly composed of aluminum oxide, which not only has an insufficient gas barrier property but also has a resistance to bending. Is also inadequate.

Japanese Patent Application Laid-Open No. 2-194944 discloses a gas barrier layer having boil resistance and retort resistance.
A stack of l ₂ O ₃ .SiO ₂ has been proposed.
However, the formation of the gas barrier layer is complicated and requires a large-scale apparatus. Moreover, from the viewpoint of achieving both gas barrier properties and bending resistance, it cannot be said that it is still insufficient. That is, in order to provide excellent gas barrier properties even after the boil treatment or the retort treatment, a film thickness of a certain level or more (for example, about 2000 ° or more) is required.
When the film thickness is large, there is a problem that the bending resistance is inferior and it cannot withstand a drop impact. Therefore, a transparent gas barrier film having sufficient gas barrier properties, having good gas barrier properties even after boil treatment or retort treatment, and further having excellent bending resistance and being able to sufficiently withstand a drop impact is currently available. However, it has not been proposed.

[0019]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to have excellent transparency, gas barrier properties and adhesiveness, and to have a good effect after boiling or retorting. In addition, to provide a gas barrier film which can be produced industrially advantageously, without impairing its excellent gas barrier properties even after a printing step, and having good bending resistance and sufficient strength properties to withstand drop impacts. It is.

[0020]

(1) A layer mainly composed of an aliphatic polyamide resin (X) and a B layer mainly composed of an aliphatic polyamide resin (Y) are A layer / B layer or A layer. layer/
An inorganic vapor-deposited layer is formed on one or both A layers of the base polyamide film having a layer constitution of B layer / A layer, and the water absorption (a) of the aliphatic polyamide resin (X) and the A gas barrier film, wherein the ratio of water absorption (b), (a) / (b), of the aliphatic polyamide resin (Y) is 0.5 or less. (2) The aliphatic polyamide resin (X) is at least one selected from the group consisting of nylon 12, nylon 612, nylon 7, nylon 11, and nylon 6 / nylon 12 copolymer, and the aliphatic polyamide resin (Y) is at least one selected from the group consisting of nylon 6, nylon 4, nylon 46 and nylon 66;
The gas barrier film according to the above (1), wherein (3) The adhesive strength between the base polyamide film and the inorganic vapor-deposited layer after boiled in hot water at 95 ° C. for 30 minutes is 100 g.
/ 15 mm or more, the gas barrier film according to the above (1). (4) between the base polyamide film and the inorganic vapor-deposited layer, a main component is a self-crosslinkable polyester-based graft copolymer obtained by graft-polymerizing at least one or more polymerizable unsaturated monomers to a hydrophobic polyester resin. The gas barrier film according to any one of the above (1) to (3), wherein an adhesion modifying layer made of a resin composition is formed. (5) The gas barrier film according to the above (4), wherein the polymerizable unsaturated monomer contains at least one selected from an acid anhydride having a double bond. (6) The gas barrier film according to (4), wherein the polymerizable unsaturated monomers are maleic anhydride and styrene. (7) The adhesion-modified layer is coated with a coating liquid containing a self-crosslinkable polyester-based graft copolymer on an unstretched or uniaxially stretched base polyamide film and dried, and then the film is uniaxially or more. The gas barrier film according to the above (4), which is a layer formed by stretching and heat setting. (8) The gas barrier film according to any one of the above (1) to (7), wherein the inorganic vapor-deposited layer is a layer containing silicon oxide and aluminum oxide. (9) The gas barrier film according to (8), wherein the content of aluminum oxide in the inorganic vapor-deposited layer is from 5% by weight to 45% by weight. (10) On the inorganic vapor-deposited layer, the heat seal layer comprising a composition containing a polyolefin resin is formed (1)
The gas barrier film according to any one of (1) to (9).

The gas barrier film of the present invention having the above-described structure has excellent gas barrier properties and adhesiveness at the initial stage and after boil treatment or retort treatment in actual use, and has transparency and bending resistance. It is a gas barrier film excellent in quality.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the gas barrier film of the present invention will be described in detail.

(Base Polyamide Film) In the present invention, the base polyamide film has a layer structure of A layer / B layer or A layer / B layer / A layer.

The layer A is a layer mainly composed of an aliphatic polyamide resin (X). Examples of the aliphatic polyamide resin (X) include nylon 7, nylon 11, nylon 12, nylon 612 and copolymers thereof. Of these, nylon 12, nylon 612, and nylon 6 / nylon 12 copolymer are preferred.

The layer B is a layer mainly composed of an aliphatic polyamide resin (Y). Examples of the aliphatic polyamide resin (Y) include nylon 4, nylon 6, nylon 46, nylon 66, and copolymers thereof. Of these, nylon 6 and nylon 66 are preferable in terms of cost.

In the present invention, the ratio (a) / (b) of the water absorption (a) of the aliphatic polyamide resin (X) to the water absorption (b) of the aliphatic polyamide resin (Y) is 0.5 or less. , Preferably 0.3 or less, more preferably 0.2 or less. When this ratio exceeds 0.5, the dimensional change of the layer A after the boil treatment and the retort treatment is large, so that the inorganic vapor deposition layer is cracked and the gas barrier property is reduced. Needless to say, the selection of the aliphatic polyamide resin (X) and the aliphatic polyamide resin (Y) is such that the ratio (a) / (b) is 0.
It is performed so as to be 5 or less.

In the present invention, since the base polyamide film is layer A / layer B or layer A / layer B / layer A and the resin constituting each layer has a water absorption ratio in the above range, the water absorption of the substrate is not limited. Therefore, it is considered that even if such a gas barrier film is subjected to a boil treatment or a retort treatment, the inorganic vapor-deposited layer is unlikely to be cracked or peeled off, and good gas barrier properties are maintained. In addition, since the aliphatic polyamide resin is used as a component of the layer A and the layer B, the gas barrier film has high strength against drop impact and bending.

The layer A and / or the layer B preferably further contain a flex fatigue resistance improving agent from the viewpoint of maintaining the flex resistance. Examples of the flex fatigue resistance improver include block polyesteramide, block polyetheramide, polyetheresteramide-based elastomer, polyester-based elastomer, modified ethylene-propylene rubber, and ethylene-acrylate copolymer.

The layer A and / or the layer B may contain a lubricity-imparting agent for preventing blocking of the films and improving lubricity. As the slipperiness imparting agent, for example,
Particle lubricants of inorganic particles such as silica, alumina and calcium carbonate, and organic particles such as cross-linked acrylic particles and cross-linked polystyrene particles; stearamide, benamide, erucamide, N-stearyl stearamide, Examples include higher fatty acid amides such as ethylenebisbehenamide and ethylenebisstearic acid amide, and organic lubricants such as fatty acid metal salts and fatty acid esters. The particle lubricant and the organic lubricant may be used alone, or may be used in combination depending on the case. Further, these particulate lubricants and organic lubricants may be added to one of the A layer and the B layer, or both may be added.

The base polyamide film can be produced by a known production method. That is, a method in which the resin compositions constituting each layer are melted using separate extruders and produced by coextrusion, a method in which the resin compositions constituting each layer are laminated by lamination, a method in which these are combined, and the like are employed. can do. Furthermore, the base polyamide film can be used either in an unstretched state or in a stretched state.However, from the viewpoint of improving the processability of the film, it is preferable to stretch and use the film in a uniaxial or biaxial direction. Is desirable. As the stretching method, tenter-type successive biaxial stretching method, tenter-type simultaneous biaxial stretching method,
A known method such as a tubular method can be used.

The thickness of the layer A is not particularly limited, but is preferably 50% or less, more preferably 5 to 30%, particularly preferably 10 to 20% based on the whole film.

As long as the object and performance of the present invention are not impaired, various additives such as a lubricant, an antioxidant, a weathering agent, an anti-gelling agent, an anti-blocking agent, a pigment, an antistatic agent and the like are appropriately compounded. Is also good. These additives are preferably blended with the resin composition constituting the outermost layer A from the viewpoint that the performance can be further exhibited.

(Inorganic Vapor Deposition Layer) An inorganic vapor deposition layer as a gas barrier layer is formed on one or both A layers of the base polyamide film. The inorganic vapor-deposited layer contains silicon oxide, aluminum oxide, magnesium oxide, a mixture thereof, or the like. In the present invention, silicon oxide is a mixture of various silicon oxides such as SiO and SiO _2, aluminum oxide is a mixture of various aluminum oxides such as AlO and Al ₂ O ₃ , and magnesium oxide is It is composed of a mixture of various magnesium oxides such as MgO. The amount of oxygen in each oxide varies depending on the production conditions.

The inorganic vapor-deposited layer containing a mixture of aluminum oxide and silicon oxide is transparent, and can impart an excellent gas barrier property that can withstand a boil treatment, a retort treatment, or a gelbo test (bending resistance test). It is particularly preferable as a gas barrier layer in the above. In this case, the content of aluminum oxide in the inorganic vapor-deposited layer is preferably from 5% by weight to 45% by weight, more preferably from 10% by weight to 35% by weight, and particularly preferably from 15% by weight to 25% by weight.
% By weight or less. If the content of aluminum oxide is less than 5% by weight, sufficient gas barrier properties may not be obtained due to lattice defects in the inorganic vapor deposition layer. Conversely, if it exceeds 45% by weight, the flexibility of the inorganic vapor deposition layer When the gas barrier film is boiled, the inorganic polyamide layer is likely to be broken (cracked or peeled) due to a dimensional change of the base polyamide film, and the gas barrier property may be deteriorated.

In the above case, other oxides and the like may be contained in trace amounts (up to 3% by weight) in addition to aluminum oxide and silicon oxide as long as the characteristics are not impaired.

The thickness of the inorganic vapor-deposited layer is usually from 10 to 50.
00 °, preferably 50 to 2000 °. The film thickness is 1
If it is less than 0 °, it is difficult to obtain a satisfactory gas barrier property, and if it exceeds 5,000 °, the effect of improving the gas barrier property cannot be obtained, and it is disadvantageous in terms of bending resistance and manufacturing cost. .

For the preparation of the inorganic vapor deposition layer, a physical vapor deposition method such as a vacuum vapor deposition method, a sputtering method or an ion plating method, or a chemical vapor deposition method such as a CVD method is appropriately used. For example, when a vacuum deposition method is adopted, a mixture of SiO ₂ and Al ₂ O ₃ or a mixture of SiO ₂ and Al is used as a deposition material. For heating, resistance heating, induction heating, electron beam heating, etc. can be adopted, and oxygen, nitrogen, hydrogen, argon, carbon dioxide gas,
It is also possible to adopt reactive vapor deposition using a means such as introduction of water vapor, addition of ozone, or ion assist. Further, the film forming conditions such as applying a bias, heating or cooling the base polyamide film can be arbitrarily changed. The above-mentioned deposition material, reaction gas, substrate bias, heating / cooling, etc.
The same applies to the case where the D method is adopted.

The gas barrier property of the gas barrier film is largely related to the adhesion strength between the base polyamide film and the inorganic vapor-deposited layer, and the gas adhesion property increases as the adhesion strength increases. According to the study results of the present inventors, it has been found that to have excellent gas barrier properties and to maintain the excellent gas barrier properties even after boil processing, it is necessary to use 95
Adhesion strength after boiling for 30 minutes in hot water
It has been confirmed that it should be 0 g / 15 mm or more, preferably 150 g / 15 mm or more, more preferably 200 g / 15 mm or more, and particularly preferably 250 g / 15 mm or more. When the adhesion strength is less than 100 g / 15 mm, the gas barrier property tends to be deteriorated by boil treatment or retort treatment. It is considered that the reason for this is that if the adhesion strength is large, the inorganic vapor-deposited layer hardly peels off even when the base polyamide film slightly shrinks due to the boil treatment or the retort treatment.

As means for obtaining such excellent adhesion strength, a corona treatment, a flame treatment, a plasma treatment, or the like may be applied to the surface of the base polyamide film before forming the inorganic vapor deposition layer.
Glow discharge treatment, reverse sputtering treatment, surface roughening treatment, etc., or a method of forming an adhesion modified layer on a base polyamide film, etc. Is preferred. Hereinafter, the adhesion modifying layer will be described.

(Adhesion-Modifying Layer) In the present invention, the adhesion-modifying layer is a self-crosslinkable polyester-based graft copolymer obtained by graft-polymerizing at least one or more polymerizable unsaturated monomers onto a hydrophobic polyester resin. It is preferable that the resin composition is composed of a resin composition mainly composed of a united product. In the present invention, “graft polymerization” refers to introducing a branch polymer made of a polymer different from the main chain into the main chain of the main polymer.

The hydrophobic polyester resin used in the present invention is an essentially water-insoluble polyester resin which does not disperse or dissolve in water by itself.

The dicarboxylic acid component of the hydrophobic polyester resin comprises 60 to 99.5 mol% of an aromatic dicarboxylic acid, 0 to 9 aliphatic dicarboxylic acids and / or alicyclic dicarboxylic acids.
It is preferably 40 mol% and 0.5 to 10 mol% of a dicarboxylic acid having a polymerizable unsaturated double bond. When the content of the aromatic dicarboxylic acid is less than 60 mol%, or when the content of the aliphatic dicarboxylic acid and / or the alicyclic dicarboxylic acid is 40 mol%
If it exceeds 3, the adhesion strength between the base polyamide film and the inorganic vapor-deposited layer may be reduced.

When the amount of the dicarboxylic acid having a polymerizable unsaturated double bond is less than 0.5 mol%, efficient graft polymerization of a polymerizable unsaturated monomer to be subsequently graft-polymerized becomes difficult, Conversely, if it exceeds 10 mol%, the viscosity will increase too much in the late stage of the graft polymerization reaction, which will hinder uniform progress of the reaction, which is not preferable. More preferably, 70 to 98 mol% of aromatic dicarboxylic acid, 0 to 30 mol% of aliphatic dicarboxylic acid and / or alicyclic dicarboxylic acid,
It is 2 to 7 mol% of a dicarboxylic acid having a polymerizable unsaturated double bond.

Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid and the like. As the aliphatic dicarboxylic acid, for example, succinic acid,
Adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, dimer acid and the like. Examples of the alicyclic dicarboxylic acid include 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid,
-Cyclohexanedicarboxylic acid and its acid anhydride.

Examples of the dicarboxylic acid having a polymerizable unsaturated double bond include fumaric acid, maleic acid, maleic anhydride,
Α, β-unsaturated dicarboxylic acids such as itaconic acid and citraconic acid; and alicyclic dicarboxylic acids such as 2,5-norbornene dicarboxylic anhydride and tetrahydrophthalic anhydride. Therefore, fumaric acid, maleic acid and 2,5-norbornene dicarboxylic acid are preferred.

Examples of the glycol component of the hydrophobic polyester resin include aliphatic glycols having 2 to 10 carbon atoms, alicyclic glycols having 6 to 12 carbon atoms, and glycols containing an ether bond. Examples of the aliphatic glycol having 2 to 10 carbon atoms include ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4
-Butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-ethyl-2-butylpropanediol, etc. And as the alicyclic glycol having 6 to 12 carbon atoms,
For example, 1,4-cyclohexanedimethanol and the like can be mentioned.

Examples of the glycol containing an ether bond include, for example, diethylene glycol, triethylene glycol, dipropylene glycol, and glycols obtained by adding ethylene oxide or propylene oxide to two phenolic hydroxyl groups of bisphenols [eg, 2, 2-bis (4-hydroxyethoxyphenyl) propane, etc.]. Polyethylene glycol, polypropylene glycol, and polytetramethylene glycol can be used if necessary.

The hydrophobic polyester resin is contained in an amount of 0 to 5 mol%.
The polycarboxylic acid and / or polyol having three or more functional groups may be used as a copolymer component. Examples of the trifunctional or higher polycarboxylic acid include (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, (anhydrous) benzophenonetetracarboxylic acid, trimesic acid, ethylene glycol bis (anhydrotrimellitate), and glycerol tris. (Anhydrotrimellitate) and the like. Examples of the trifunctional or higher functional polyol include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. The tri- or higher functional polycarboxylic acid or polyol is preferably 0 to 5 mol% in all dicarboxylic acid components or all glycol components, respectively.
More preferably, it is copolymerized in the range of 0 to 3 mol%,
If it exceeds 5 mol%, gelation during polymerization tends to occur, which is not preferable.

The molecular weight of the hydrophobic polyester resin is preferably in the range of 5,000 to 50,000 in terms of weight average molecular weight. If the molecular weight is less than 5000, the adhesion strength between the base polyamide film and the inorganic vapor-deposited layer may be reduced. If it exceeds 50,000, problems such as gelation during polymerization may occur.

Examples of the polymerizable unsaturated monomer graft-polymerized to the hydrophobic polyester resin include fumaric acid;
Monoesters or diesters of fumaric acid such as monoethyl fumarate, diethyl fumarate and dibutyl fumarate;
Maleic acid and its anhydride; monoester or diester of maleic acid such as monoethyl maleate, diethyl maleate, dibutyl maleate; itaconic acid and its anhydride; monoester or diester of itaconic acid;
Maleimides such as phenylmaleimide; styrene, α-
Examples of styrene derivatives such as methylstyrene, t-butylstyrene, chloromethylstyrene, vinyltoluene, and divinylbenzene, and acrylic polymerizable monomers include, for example, alkyl (meth) acrylates (where alkyl groups are methyl, ethyl, n -Propyl group, isopropyl group, n
-Butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, phenyl group, benzyl group, phenylethyl group, etc.); 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-
Hydroxy group-containing (meth) acrylic monomers such as hydroxypropyl acrylate and 2-hydroxypropyl methacrylate; acrylamide, methacrylamide, N-
Methyl methacrylamide, N-methylacrylamide,
N-methylol acrylamide, N-methylol methacrylamide, N, N-dimethylol acrylamide, N
Amide group-containing (meth) acrylic monomers such as -methoxymethylacrylamide, N-methoxymethylmethacrylamide and N-phenylacrylamide; amino group-containing such as N, N-diethylaminoethyl acrylate and N, N-diethylaminoethyl methacrylate ( (Meth) acrylic monomer; epoxy group-containing (meth) acrylic monomer such as glycidyl acrylate and glycidyl methacrylate; and carboxyl group-containing such as acrylic acid, methacrylic acid and salts thereof (sodium salt, potassium acid, ammonium salt) ( (Meth) acrylic monomers and the like. The above monomers can be copolymerized by using one kind or two or more kinds. Among these, styrene and maleic anhydride are preferred.

The weight ratio of the hydrophobic polyester resin and the polymerizable unsaturated monomer in the graft copolymer, that is, the ratio of the hydrophobic polyester resin / polymerizable unsaturated monomer is preferably from 40/60 to 95/5, more preferably from 40/60 to 95/5. Preferably 55 / 45-9
It is 3/7, particularly preferably 60/40 to 90/10. When the weight ratio of the hydrophobic polyester resin is less than 40% by weight, the excellent adhesiveness of the hydrophobic polyester resin may not be exhibited. Certain blocking is more likely to occur.

The graft copolymer used for the adhesion modifying layer is generally prepared by adding a polymerization initiator and a polymerizable unsaturated monomer in a state where a hydrophobic polyester resin is dissolved in an organic solvent. To be obtained. The reaction product after the completion of the graft polymerization reaction is, in addition to the desired graft copolymer, a hydrophobic polyester resin that has not been subjected to graft polymerization and a polymerizable unsaturated monomer that has not been graft-polymerized to the hydrophobic polyester resin. In the present invention, the graft copolymer includes all of these.

In the present invention, the acid value of the graft copolymer is 600 equivalents / 10 ⁶ g or more, particularly 1200 equivalents / 1.
It is preferably at least ⁶ g. If the acid value is less than 600 equivalents / 10 ⁶ g, the adhesiveness between the base polyamide film and the inorganic vapor-deposited layer may be insufficient.

The above graft copolymer is in the form of a solution or dispersion of an organic solvent or a solution or dispersion of an aqueous solvent. In particular, a dispersion of an aqueous solvent, that is, a form of a water-dispersed resin is preferable in terms of working environment and applicability. In order to obtain such a water-dispersed resin, usually, in an organic solvent, the hydrophobic polyester resin is graft-polymerized with a polymerizable unsaturated monomer including a hydrophilic polymerizable unsaturated monomer, This is achieved by adding water and distilling off the organic solvent.

The above-mentioned hydrophilic polymerizable unsaturated monomer refers to a polymerizable unsaturated monomer having a hydrophilic group or a group which can be converted into a hydrophilic group. Examples of the hydrophilic group include a carboxyl group, a hydroxyl group, a phosphoric acid group, a phosphorous acid group, a sulfonic acid group, an amide group, and a quaternary ammonium base.
Examples of the group that can be converted to a hydrophilic group include, for example, an acid anhydride group,
Glycidyl group, chloro group and the like can be mentioned. Among these, from the viewpoint of water dispersibility and the point that the acid value of the graft copolymer becomes high, a polymerizable unsaturated compound having a carboxyl group or a group capable of changing to a carboxyl group (for example, an acid anhydride group). It is preferred to use monomers. Such a hydrophilic polymerizable unsaturated monomer, among those exemplified as the polymerizable unsaturated monomer, a carboxyl group,
Monomers having an acid anhydride group, a hydroxyl group, an amino group and the like are mentioned, and among them, monomers having an acid anhydride group, particularly maleic anhydride, are preferable.

When the graft copolymer is a water-dispersible resin, the weight average molecular weight of the polymer component of the polymerizable unsaturated monomer as a branch polymer in the graft copolymer is 500 to 50.
000 is preferred. It is generally difficult to control the weight-average molecular weight of the polymer component to 500 or less, and the graft efficiency tends to decrease, and the hydrophilic group tends not to be sufficiently imparted to the hydrophobic polyester resin. In addition, the polymer component of the polymerizable unsaturated monomer in the graft copolymer forms a hydrated layer of the dispersed particles, but in order to have a hydrated layer of a sufficient thickness, to obtain a stable dispersion The weight average molecular weight of the polymer component is desirably 500 or more. Further, the upper limit of the weight average molecular weight of the polymer component is preferably 50,000 from the viewpoint of polymerizability in solution polymerization. Control of the molecular weight within this range, the amount of polymerization initiator used, monomer dropping time, polymerization time, reaction solvent, monomer composition or by appropriately combining a chain transfer agent and a polymerization inhibitor as needed. Can do it.

The above water-dispersible resin can be obtained in various particle sizes by a polymerization method. The average particle size measured by a laser light scattering method is suitably from 10 to 500 nm, and the dispersion stability is stable. The thickness is preferably 400 nm or less, more preferably 300 nm or less, from the viewpoint of properties. 500
If it exceeds 500 nm, the film-forming property is reduced and the coating film becomes non-uniform, and the transparency of the coating material is lowered due to a decrease in the gloss of the surface of the coating film. The properties may be poor, which is not preferred.

In order to obtain the water-dispersed graft copolymer, the graft polymerization is preferably performed using an aqueous organic solvent having a boiling point of 50 to 250 ° C. as a reaction solvent. Here, the aqueous organic solvent is 2
Solubility in water at 0 ° C. of at least 10 g / l
As described above, it is preferably 20 g / l or more. Those having a boiling point exceeding 250 ° C have a low evaporation rate and cannot be sufficiently removed by high-temperature baking of the coating film. Conversely, if the boiling point is lower than 50 ° C, graft polymerization using the solvent as a solvent will result in a temperature below 50 ° C. However, it is necessary to use an initiator that cleaves into radicals, which increases the danger in handling, which is not preferable. Such aqueous organic solvents include the following first group of aqueous organic solvents and / or second group of aqueous organic solvents.

Solvent which dissolves the hydrophobic polyester resin well and relatively well dissolves the polymerizable unsaturated monomer containing the hydrophilic polymerizable unsaturated monomer and the graft copolymer thereof with the hydrophobic polyester resin. Examples of the first group of aqueous organic solvents are esters such as ethyl acetate; ketones such as methyl ethyl ketone, methyl isobutyl ketone,
Cyclohexanone; cyclic ethers such as tetrahydrofuran, dioxane, 1,3-dioxolane; glycol ethers such as ethylene glycol dimethyl ether, propylene glycol methyl ether, propylene glycol propyl ether, ethylene glycol ethyl ether, ethylene glycol butyl ether; carbitols such as methyl carbitol Ethyl carbitol, butyl carbitol; lower esters of glycols or glycol ethers such as ethylene glycol diacetate, ethylene glycol ethyl ether acetate; ketone alcohols such as diacetone alcohol; and N-substituted amides such as dimethylformamide, dimethyl Acetamide, N-methylpyrrolidone, etc.

Solvent which hardly dissolves the hydrophobic polyester resin but relatively well dissolves the polymerizable unsaturated monomer containing the hydrophilic polymerizable unsaturated monomer and the graft copolymer of the polymerizable unsaturated monomer and the hydrophobic polyester resin. Examples of the second group of aqueous organic solvents include water, lower alcohols, lower carboxylic acids, lower amines, and the like. Particularly preferred are alcohols and glycols having 1 to 4 carbon atoms.

When the graft polymerization is carried out in a single solvent,
It can be carried out by selecting only one kind from the first group of aqueous organic solvents. When using a mixed solvent, there are a case where a plurality of types are selected only from the first group of aqueous organic solvents, and a case where at least one type is selected from the first group of aqueous organic solvents and at least one type is added from the second group of aqueous organic solvents. In consideration of the progress of the graft polymerization reaction, the appearance, properties, etc. of the graft copolymer and the aqueous dispersion derived therefrom, it is preferable to use a mixed solvent composed of each of the first and second groups of aqueous organic solvents. Good.

In the first group of solvents, the hydrophobic polyester molecular chains are in a state of extending a chain having a large spread, and in a mixed solvent of the first group / second group, they are in a state of being entangled in a thread form having a small spread. This was confirmed by measuring the viscosity of the hydrophobic polyester resin in these solutions. It is effective to prevent gelation by adjusting the dissolving state of the hydrophobic polyester resin so as to prevent intermolecular crosslinking. Both high efficiency of graft polymerization and suppression of gelation are achieved in the latter mixed solvent system. The weight ratio of the mixed solvent of the first group / second group is preferably 95/5 to 10/90, more preferably 90 /.
10/20/80, particularly preferably 85 / 15-30 /
70. The optimum mixing ratio is determined according to the solubility of the hydrophobic polyester resin used.

In the above graft polymerization, a polymerization initiator, for example, a known organic peroxide or organic azo compound may be used. Examples of the organic peroxide include benzoyl peroxide and t-butyl peroxypivalate. Examples of the organic azo compound include 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4- Dimethylvaleronitrile) and the like. The amount of the polymerization initiator used for performing the graft polymerization is based on the polymerizable unsaturated monomer.
At least 0.2% by weight or more, preferably 0.5% by weight
That is all.

In addition to the polymerization initiator, a chain transfer agent for adjusting the chain length of the branch polymer, for example, octyl mercaptan, mercaptoethanol, 3-t-butyl-4-hydroxyanisole, etc. can be used as required. . In this case, it is desirable to add in the range of 0 to 5% by weight based on the polymerizable unsaturated monomer.

In the present invention, the graft copolymer is preferably neutralized with a basic compound, and can be easily dispersed in water by neutralization. As the basic compound, a compound which volatilizes at the time of forming a coating film or baking hardening by blending a hardening agent is desirable, and ammonia, triethylamine, N, N-diethylethanolamine, N,
N-dimethylethanolamine, aminoethanolamine, N-methyl-N, N-diethanolamine, isopropylamine, iminobispropylamine, ethylamine, diethylamine, 3-ethoxypropylamine, 3
Organic amines such as -diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, dimethylaminopropylamine, methyliminobispropylamine, 3-methoxypropylamine, monoethanolamine, diethanolamine and triethanolamine. . The pH value of the aqueous dispersion of the basic compound is adjusted to 5.0 by partial neutralization or complete neutralization depending on the carboxyl group content in the graft copolymer.
It is desirable to use it so as to be in the range of 9.0 to 9.0. When a basic compound having a boiling point of 100 ° C. or less is used, the residual basic compound in the coating film after drying is small, the adhesiveness between the base polyamide film and the inorganic vapor-deposited layer is excellent, and the water resistance of the adhesion modified layer is excellent. And excellent hot water adhesion.

In the present invention, the graft copolymer obtained by graft-polymerizing a polymerizable unsaturated monomer onto a hydrophobic polyester resin has a self-crosslinking property. Does not crosslink at room temperature,
Crosslinking is carried out without a crosslinker by using 1) a dehydration reaction of a carboxyl group present in the graft copolymer or 2) an intermolecular reaction such as a hydrogen abstraction reaction due to a heat radical with heat during drying after coating. Thus, for the first time, the adhesion between the base polyamide film and the inorganic vapor-deposited layer and the water resistance of the adhesion-modified layer can be exhibited. Although the crosslinkability of the coating film can be evaluated by various methods, it can be examined by the insoluble content in chloroform in which the graft copolymer is dissolved. The coating film obtained by drying at 80 ° C. or lower and heat-treating at 120 ° C. for 5 minutes preferably has an insoluble content of 50% or more, more preferably 70% or more. When the insoluble content of the coating film is less than 50%, not only the adhesion and water resistance are not sufficient, but also blocking occurs.

The above graft copolymer can form an adhesion-modified layer as it is. However, by adding a crosslinking agent (curing resin) and curing, the adhesion-modified layer can have high water resistance. May be granted.

Examples of the crosslinking agent include phenol formaldehyde resins which are condensates of alkylated phenols, cresols, etc. with formaldehyde; adducts of urea, melamine, benzoguanamine, etc. with formaldehyde; And polyfunctional epoxy compounds; polyfunctional isocyanate compounds; blocked isocyanate compounds: polyfunctional aziridine compounds; oxazoline compounds, and the like.

As the phenol formaldehyde resin, for example, alkylated (methyl, ethyl, propyl,
Isopropyl or butyl) phenol, pt-amylphenol, 4,4'-sec-butylidenephenol, pt-butylphenol, o-, m-, p-cresol, p-cyclohexylphenol, 4,4'- Isopropylidenephenol, p-nonylphenol, p
-Octylphenol, 3-pentadecylphenol,
Examples include condensates of phenols such as phenol, phenyl o-cresol, p-phenylphenol, and xylenol with formaldehyde.

Examples of the amino resin include methoxylated methylol urea, methoxylated methylol N, N-ethylene urea, methoxylated methylol dicyandiamide, methoxylated methylol melamine, methoxylated methylol benzoguanamine, butoxylated methylol melamine, and butoxylated methylol benzoguanamine. And preferably methoxylated methylolmelamine, butoxylated methylolmelamine, methylolated benzoguanamine and the like.

Examples of the polyfunctional epoxy compound include diglycidyl ethers of bisphenol A and oligomers thereof, diglycidyl ethers of hydrogenated bisphenol A and oligomers thereof, diglycidyl orthophthalate, diglycidyl isophthalate, and the like.
Diglycidyl terephthalate, diglycidyl p-oxybenzoate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, diglycidyl succinate, diglycidyl adipate, diglycidyl sebacate, ethylene Glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether and polyalkylene glycol diglycidyl ethers, trimellitic acid triglycidyl ester, triglycidyl isocyanate Nurate,
1,4-diglycidyloxybenzene, diglycidylpropylene urea, glycerol triglycidyl ether,
Examples include trimethylolpropane triglycidyl ether, pentaerythritol triglycidyl ether, and triglycidyl ether of a glycerol alkylene oxide adduct.

Examples of the polyfunctional isocyanate compound include:
For example, low molecular weight or high molecular weight aromatic and aliphatic diisocyanates and trivalent or higher polyisocyanates can be mentioned. Examples of the polyisocyanate include tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, and trimers of these isocyanate compounds. Further, excess amounts of these isocyanate compounds, ethylene glycol, propylene glycol, trimethylolpropane,
Terminals obtained by reacting with a low molecular weight active hydrogen compound such as glycerin, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, or a high molecular weight active hydrogen compound such as polyester polyols, polyether polyols, and polyamides. An isocyanate group-containing compound is exemplified.

The blocked isocyanate can be prepared by subjecting the above isocyanate compound and a blocking agent to an addition reaction by a conventionally known appropriate method. Examples of the isocyanate blocking agent include phenols such as phenol, cresol, xylenol, resorcinol, nitrophenol, and chlorophenol; thiophenols such as thiophenol and methylthiophenol; oximes such as acetoxime, methylethylketoxime, and cyclohexanone oxime; Alcohols such as methanol, ethanol, propanol and butanol; halogen-substituted alcohols such as ethylene chlorohydrin and 1,3-dichloro-2-propanol; tertiary alcohols such as t-butanol and t-pentanol; -Caprolactam,
Lactams such as δ-valerolactam, γ-butyrolactam, β-propyllactam; aromatic amines; imides; active methylene compounds such as acetylacetone, acetoacetate, and malonic acid ethyl ester; mercaptans; imines; Diaryl compounds; sodium bisulfite and the like.

These crosslinking agents may be used alone or in combination.
A mixture of more than one species can be used. The amount of the crosslinking agent is 5 parts by weight to 40 parts by weight based on 100 parts by weight of the graft copolymer.
Parts by weight are preferred. (1)
When the cross-linking agent is water-soluble, a method of directly dissolving or dispersing it in an aqueous solvent solution or dispersion of the graft copolymer, or (2) when the cross-linking agent is oil-soluble, after completion of the grafting reaction, Is added. These methods can be appropriately selected depending on the type and properties of the crosslinking agent. Further, a curing agent or an accelerator can be used in combination with the crosslinking agent.

The above graft copolymers may be used in combination with general-purpose polyester resins, urethane resins, acrylic resins, copolymers thereof, various water-soluble resins, and various functional resins (for example, conductive resins such as polyaniline and polypyrrole). An antibacterial resin, an ultraviolet absorbing resin, a gas barrier resin) may be blended to form the adhesion modified layer.

The adhesion modifying layer may further contain additives such as various surfactants, antistatic agents, inorganic lubricants, organic lubricants, and ultraviolet absorbers as long as the effects of the present invention are not impaired.

The formation of the adhesion-modified layer may be carried out by preparing an organic solvent solution or dispersion of the graft copolymer or a solution or dispersion of an aqueous solvent, preferably an aqueous solvent dispersion, preferably using an unstretched or uniaxially stretched substrate. It is carried out by coating and drying on a polyamide film. The solid content of the graft copolymer in the above solution or dispersion is generally 1% by weight to 50% by weight, preferably 3% by weight to 30% by weight.

As a coating method, known methods such as a gravure method, a reverse method, a die method, a bar method, and a dip method are employed. The coating amount of the coating solution is 0.005 to 10 g / m ² , preferably 0.02 to 0.
5 g / m ² . When the coating amount is less than 0.005 g / m ² , sufficient adhesion strength between the base polyamide film and the inorganic vapor-deposited layer cannot be obtained. If it exceeds 10 g / m ² , blocking occurs and there is a practical problem.

The drying conditions after coating are not particularly limited, but in order to exhibit the self-crosslinking property of the graft copolymer,
As long as the heat degradation does not occur in the base polyamide film and the graft copolymer, it is preferable to increase the amount of heat. Specifically, 80 ° C. to 250 ° C., more preferably 1 ° C.
50 ° C to 220 ° C. However, by extending the drying time, sufficient self-crosslinking property is exhibited even at a relatively low temperature, so that the conditions are not limited to the above.

When the above coating solution is applied to an unstretched or uniaxially stretched base polyamide film and dried, and then the film is stretched uniaxially or more, the drying temperature after the application is within a range not affecting the subsequent stretching. In the case of a base polyamide film, the film must be dried under the conditions described above and stretched with the water content of the film being 2% or less, and then heat-fixed at 200 ° C. or more, so that the film becomes strong and the adhesive property is improved. The adhesion between the layer and the base polyamide film is dramatically improved. If the water content exceeds 2%, depending on the drying temperature, crystallization is likely to occur during the transverse stretching step, which may deteriorate the flatness and impair the stretchability.

When the above coating solution is applied to the biaxially stretched base polyamide film, the base material is formed before the formation of the adhesion modified layer in order to further improve the adhesion between the base polyamide film and the adhesion modified layer. The polyamide film may be subjected to a surface treatment such as a corona treatment, a flame treatment, and electron beam irradiation.

The adhesion-modified layer has good adhesion to various materials, and in the present invention, an inorganic vapor-deposited layer is formed thereon. The surface of the adhesion-modified layer may be further subjected to a corona treatment, a flame treatment, an electron beam irradiation or the like.

In actual use, on the surface of the above-mentioned inorganic vapor-deposited layer, a heat seal layer mainly made of a polyolefin-based resin for providing thermal adhesion is formed. Examples of the polyolefin resin constituting the heat seal layer include LDPE, LLDPE, CPP and the like. The heat seal layer does not necessarily have to be a single layer and may be a multilayer, and the resin constituting each layer when forming a multilayer structure, not only a combination of resins of the same kind, but also a copolymer of a different polymer or Modified products, blended products and the like may be laminated. For example, a polymer having a glass transition temperature (Tg) or a melting point lower than that of the thermoplastic polyolefin resin as a base is blended in order to enhance laminating property and heat sealing property, and conversely, a Tg or melting point is added to impart heat resistance. It is also possible to incorporate high polymers.

Various additives such as a plasticizer, a heat stabilizer, an ultraviolet absorber, an antioxidant, a coloring agent, a filler, and the like may be added to the resin composition constituting the heat seal layer, if necessary.
It is also possible to blend antistatic agents, antibacterial agents, lubricants, antiblocking agents, other resins, and the like.

The heat sheet layer can be formed as a heat seal layer on the inorganic resin layer by a dry lamination method or a wet lamination method using an adhesive, or a melt extrusion lamination method or a coextrusion lamination method. ,
The heat seal layer also has a function as a protective layer of the inorganic vapor-deposited layer, and in order to effectively perform the function, increasing the adhesive force between the inorganic vapor-deposited layer and the heat seal layer is extremely effective. It is extremely effective to provide an adhesive layer between the inorganic vapor deposition layer and the heat seal layer as a means for achieving this.

As the resin constituting the adhesive layer, a resin having a glass transition temperature in the range of -10 ° C. to 40 ° C., for example, a polyurethane resin, a polyester resin, an epoxy resin,
Preference is given to vinyl chloride resins, vinyl acetate resins, polyethylene resins, polypropylene resins, melamine resins, acrylic resins and the like, and these may be used alone or in combination of two or more. A compound having a carboxyl group, an acid anhydride group, a (meth) acrylic acid or a (meth) acrylate ester skeleton; an epoxy compound having a glycidyl group or a glycidyl ether group; an oxazoline group, an isocyanate group, an amino group, a hydroxyl group, etc. It is also effective to use an adhesive composition containing a curing agent or a curing accelerator having a reactive functional group.

The gas barrier film of the present invention thus obtained makes use of its excellent gas barrier properties, gas barrier persistence after boil treatment and retort treatment, and secondary processing characteristics, and is used for miso, pickles, prepared dishes, baby food, boiled tsukudani, konjac , Chikuwa, kamaboko, fishery products, meatballs,
Hamburger, Genghis Khan, ham, sausage, other processed meat products, tea, coffee, tea, bonito, kelp, potato chips, butter peanuts and other oil confections, rice crackers, biscuits, cookies, cakes, buns, castella, cheese,
It can be effectively used as food for butter, cut rice cake, soup, sauce, ramen, wasabi, etc., and packaging materials for toothpaste, etc., and for packaging pet food, pesticides, fertilizers, infusion packs, semiconductors and precision materials. It can be effectively used for materials and also for packaging materials for industrial materials such as medical, electronic, chemical, and mechanical.

The form of the packaging material is not particularly limited.
It can be widely applied to bags, lid materials, cups, tubes, standing packs and the like.

[0089]

Next, the present invention will be described in detail with reference to examples. The present invention is naturally not limited by the following examples, and it is of course possible to implement the present invention with appropriate modifications within a range that can be adapted to the spirits of the preceding and the following. Is included. Also,
Various performance tests employed in the following Examples were performed by the following methods.

1. Oxygen Permeability Oxidation Permeability Analyzer (“OX-TRAN 10 / 50A”) for gas barrier film Medern Controls
Was measured at a humidity of 0% and a temperature of 25 ° C.

2. Water Vapor Permeability The gas barrier film was measured at a humidity of 0% and a temperature of 25 ° C. using a water vapor permeability measuring device (“PERMATRAN” manufactured by Medern Controls).

3. Adhesion strength The gas barrier film was peeled 180 ° using “Tensilon UTM2” manufactured by Toyo Sokki Co. while adhering water to the interface between the inorganic vapor-deposited layer and the base polyamide film. The SS curve between them was measured and determined.

4. Flex fatigue resistance test The gas barrier film was evaluated for flex fatigue resistance test (hereinafter, gelbo test) using a gelbo flex tester manufactured by Rigaku Corporation. The condition is (MIL-
B131H) A DE 112 inch × 8 inch test piece was made into a cylindrical shape with a diameter of 3 (１ ／) inch, both ends were held, an initial gripping interval was 7 inches, and a stroke of 3 (１ ／) inch, 400 degrees. Add a twist. This operation is repeated 1000 times at a speed of 40 times / min. The measurement atmosphere is 20 ° C. and the relative humidity is 65%.
The number of pinholes at this time was counted.

5. Water absorption ratio Regarding the aliphatic polyamide resins (a) and (b) constituting the A layer and the B layer of the base polyamide film, each of the resins (a) and (b) was made into a single-layer film, and
After immersion in water at 23 ° C. for 24 hours in accordance with STM D570, the water absorption was determined from the weight before and after immersion, and (a) / (b) was calculated from the value.

6. Dimensional change The dimensional change due to humidity expansion of the base polyamide film was measured for its moisture absorption dimensional elongation by a combination of a thermal stress / strain measuring device TMA (manufactured by Vacuum Riko Co., Ltd.) and a gas humidifier. A sample is cut into a base polyamide film having a length of 50 mm and a width of 4 mm, and is set in a TMA device. 80% RH → 35% RH → 73
The relative humidity was changed from% RH to 35% RH. However, in each setting, the humidity was changed after the response was stabilized for 30 minutes. The method of calculating the moisture absorption elongation was in accordance with the following equation. Elongation in the width direction of the base polyamide film during the change of humidity: time: x1 (%) Elongation in the width direction of the base polyamide film during the change of humidity: x2 (%) Difference in humidity of the base polyamide film during the change of humidity :
y1 (%) Humidity change-Humidity difference of base polyamide film at the time:
y2 (%) From these values, the elongation in the width direction of the base polyamide film per 60% of humidity was calculated by the following equation. z1 = x1 / y1.times.60 z2 = x2 / y2.times.60 The dimensional elongation (%) of moisture absorption was the average value of z1 and z2.
Those having a moisture absorption dimensional elongation (%) of 2.0 or less were regarded as good products. The “width direction” of the base polyamide film refers to a direction orthogonal to the flow direction of the film.

(Preparation of Hydrophobic Polyester Resin) In a stainless steel autoclave equipped with a stirrer, a thermometer, and a partial reflux condenser, 345 parts by weight of dimethyl terephthalate, 211 parts by weight of 1,4-butanediol, and 270 parts of ethylene glycol were added. Parts by weight, and tetra-
Charge 0.5 parts by weight of n-butyl titanate,
To 220 ° C. for 4 hours. Then, 14 parts by weight of fumaric acid and sebacic acid 1
60 parts by weight were added, and the temperature was raised from 200 ° C. to 220 ° C. over 1 hour to carry out an esterification reaction. Then 255 ° C
Temperature, and gradually reduced the pressure of the reaction system.
The reaction was carried out under a reduced pressure of Hg for 1 hour and 30 minutes to obtain a polyester. The obtained polyester was pale yellow and transparent.

The weight average molecular weight measured by NMR was 200
The composition was as follows (unit mol%). Terephthalic acid: 70 Sebacic acid: 26 Fumaric acid: 4 Ethylene glycol: 50 1,4-butanediol: 50

(Preparation of Graft Copolymer and Coating Solution)
In a reactor equipped with a stirrer, a thermometer, a reflux device, and a fixed-rate dropping device, 75 parts by weight of the hydrophobic polyester resin, 56 parts by weight of methyl ethyl ketone, and 1 part of isopropyl alcohol
9 parts by weight were added, and the mixture was heated and stirred at 65 ° C. to dissolve the resin. After the resin was completely dissolved, 15 parts by weight of maleic anhydride was added to the polyester solution. Next, a solution prepared by dissolving 10 parts by weight of styrene and 1.5 parts by weight of azobisdimethylvaleronitrile in 12 parts by weight of methyl ethyl ketone was dropped into the polyester solution at 0.1 ml / min, and stirring was further continued for 2 hours. After sampling for analysis from the reaction solution, 5 parts by weight of methanol was added. Next, 300 parts by weight of water and 15 parts by weight of triethylamine were added to the reaction solution and stirred for 1 hour. Then, the temperature inside the reactor was reduced to 1
The temperature was raised to 00 ° C., and methyl ethyl ketone, isopropyl alcohol and excess ammonia were distilled off to obtain a water-dispersed graft copolymer. The graft copolymer was pale yellow and transparent. The graft copolymer was prepared with a solid concentration of 1
Water: isopropyl alcohol = 0% by weight
It was diluted at a ratio of 9: 1 (weight ratio) to prepare a coating solution.

Example 1 100 parts by weight of nylon 12 (Daiamide D1940, manufactured by Daicel Hulls Co., Ltd.) as layer A, and 100 parts by weight as layer B
A weight part of nylon 6 was melt-extruded while being laminated from a T-die, and cooled on a rotating drum at 20 ° C. to obtain an unstretched polyamide film having a thickness of 180 μm. This film has a layer structure of A layer / B layer / A layer, and the thickness of each layer is A layer: B
Layer: Layer A was melt coextruded and laminated at a thickness of 1.5: 7.0: 1.5. This unstretched film was longitudinally stretched 3.0 times at 50 ° C., and then the above-mentioned water-dispersed graft copolymer-containing coating solution was applied so that the thickness after drying was about 0.1 μm, and dried. Next, the film was stretched 4.0 times in the transverse direction at 125 ° C.
Heat fixing was performed at 15 ° C. to obtain a biaxially stretched film having a thickness of 15 μm.

This film was sent to a vacuum deposition apparatus, and the inside of the chamber was maintained at a pressure of 1 × 10 ⁻⁵ Torr,
₂ mixed oxide of 70% by weight and 30% by weight of Al ₂ O ₃
Evaporation was performed by heating with 5 kW of electron beam, and a colorless and transparent inorganic vapor-deposited layer having a thickness of 200 ° was formed on the adhesion modified layer. Next, unstretched polyethylene (thickness: 55 μm) as a sealant layer was dry-laminated on the inorganic vapor-deposited layer with an adhesive (“A310 / Al0” manufactured by Takeda Pharmaceutical Co., Ltd., coating amount: 2 g / m ² ). After aging for days, a gas barrier film was obtained. Regarding each single-layer film, the base polyamide film and the gas barrier film of the aliphatic polyamide resins (a) and (b) used for the base polyamide film, (1) water absorption ratio: (a) / (b) ( 2) Moisture absorption dimension elongation: width direction (%) (3) Number of pinholes (bending 1000 times) after bending fatigue test (4) Number of pinholes (bending 3000 times) after bending fatigue test (5) Enzyme permeability of untreated film (cc / m ² · at)
(6) After immersion in 95 ° C hot water for 30 minutes, oxygen permeability of the film after leaving for 1h (cc / m ² · atm · day) (7) 30 minutes in 95 ° C hot water After immersion, the water vapor permeability (g / m ² · day) of the film left for 1 h (8) After immersion in hot water of 95 ° C. for 30 minutes, the base polyamide film and the inorganic vapor deposition layer of the film left for 1 h The adhesion strength (g / 15 mm) between the base polyamide film and the inorganic vapor-deposited layer when water was dropped on the peeling interface was measured. Table 1 shows the results.

Example 2 A gas barrier film was obtained in the same manner as in Example 1, except that 100 parts by weight of nylon 612 was used as the A layer.

Example 3 In Example 1, the thickness of each layer of the polyamide film having the layer constitution of layer A / layer B / layer A was set as follows: layer A: layer B: layer A = 0.5:
Except having set it to 9.0: 0.5, it carried out exactly like Example 1, and obtained the gas barrier film.

Comparative Example 1 In Example 1, 100 parts by weight of Nylon 6 was used for the A layer, and a polyester coating agent (aqueous dispersion obtained by acrylic grafting on hydrophobic polyester, A gas barrier film was obtained in exactly the same manner as in Example 1 except that Spinning Co., Ltd. “AGN131”) was used.

[0104]

[Table 1]

As is apparent from Table 1, the gas barrier films obtained in Examples 1 to 3 were obtained by using the aliphatic amine resins (a) and (b) used for the base polyamide film.
The water absorption ratio (a) / (b) is 0.5 or less, the moisture absorption dimensional elongation of the base polyamide film is small, the gas barrier property is good even after the boil treatment, and the base polyamide film has The adhesion strength with the inorganic vapor deposition layer and the bending resistance were good. However, the gas barrier film obtained in Comparative Example 1 has a water absorption ratio (a) / (b) of the aliphatic amine resin (a) and (b) of more than 0.5, and the base polyamide film Has a large moisture absorption dimensional elongation, is inferior in adhesion strength and gas barrier property between the base material after boil treatment and the inorganic vapor deposition layer, and is also inferior in bending resistance.

[0106]

As is apparent from the above description, the gas barrier film of the present invention has a base polyamide film of A
In the layer / B layer or the A layer / B layer / A layer, since the water absorption ratio of the resin constituting each layer is in the above range, the dimensional change due to water absorption of the substrate is small and stable. Even if the gas barrier film is subjected to a boil treatment or a retort treatment, the inorganic vapor-deposited layer is unlikely to be cracked or peeled off, and good gas barrier properties are maintained. In addition, since the aliphatic polyamide resin is used as a component of the layer A and the layer B, the gas barrier film has high strength against drop impact and bending. Furthermore, by forming an adhesion-modified layer between the base polyamide film and the inorganic vapor-deposited layer, the water resistance of the adhesion-modified layer is good even when a boil treatment or a retort treatment is performed. Low water penetration at the interface of the base polyamide film. Therefore, peeling and floating of the inorganic vapor-deposited layer from the surface of the base polyamide film or deterioration of the inorganic vapor-deposited layer due to a chemical change is suppressed.

Continued on the front page (72) Inventor Shinji Fujita 2-1-1 Katata, Otsu-shi, Shiga Prefecture Inside Toyobo Co., Ltd. (72) Inventor Chikao Morishige 2-1-1 Katata, Otsu-shi, Shiga Toyobo (72) Inventor Seiichiro Yokoyama 2-1-1 Katada, Otsu-shi, Shiga Prefecture Toyobo Co., Ltd. (72) Kiyoji Iseki 2-1-1 Katata, Otsu-shi, Shiga Prefecture Toyobo (72) Inventor Yozo Yamada 2-1-1 Katata, Otsu City, Shiga Prefecture Toyobo Research Institute F-term (reference) 4F071 AA45 AA54B AA56B AA77 AE02 AF10B AF19 AH04 AH05 BA02 BB07 BC01 4F100 AA02D AA02E AA19D AA19E AA20D AA20E AK02G AK03E AK04 AK12G AK24G AK41G AK48A AK48B AK48C AK48J AL01A AL01C AL01G BA04 BA05 BA08 BA10D BA10E BA26 CB00 EH66D EH66E EJ37 EJ37A GB15 JA20 JB06G JD02 JK04 JK06 JK10 JL02 JL11 JL11E JN01 YY00 4J002 BN171 FD140 GF00 GG00 GG02 GJ00 4 K029 AA11 AA25 BA44 BA46 BC00 GA03

Claims (10)

[Claims] 1. An A layer having an aliphatic polyamide resin (X) as a main component and a B layer having an aliphatic polyamide resin (Y) as a main component, wherein A layer / B layer or A layer / B layer / A layer. An inorganic vapor-deposited layer is formed on one or both A layers of the base polyamide film having a layer structure of (a), and the water absorption (a) of the aliphatic polyamide resin (X) and the aliphatic polyamide resin ( A gas barrier film, wherein the ratio (a) / (b) of water absorption (b) of Y) is 0.5 or less. 2. The aliphatic polyamide resin (X) is at least one selected from the group consisting of nylon 12, nylon 612, nylon 7, nylon 11, and nylon 6 / nylon 12 copolymer, and is aliphatic. Polyamide resin (Y) is nylon 6, nylon 4, nylon 4
The gas barrier film according to claim 1, wherein the gas barrier film is at least one selected from the group consisting of nylon 6 and nylon 66. 3. The gas barrier property according to claim 1, wherein the adhesion strength between the base polyamide film and the inorganic vapor-deposited layer after boiled in hot water at 95 ° C. for 30 minutes is 100 g / 15 mm or more. the film. 4. A self-crosslinkable polyester-based graft copolymer obtained by graft-polymerizing at least one or more polymerizable unsaturated monomers onto a hydrophobic polyester resin between a base polyamide film and an inorganic vapor-deposited layer. The gas barrier film according to any one of claims 1 to 3, wherein an adhesion reforming layer made of a resin composition as a component is formed. 5. The gas barrier film according to claim 4, wherein the polymerizable unsaturated monomer contains at least one selected from an acid anhydride having a double bond. 6. The gas barrier film according to claim 4, wherein the polymerizable unsaturated monomers are maleic anhydride and styrene. 7. An adhesion-modified layer, after applying a coating solution containing a self-crosslinkable polyester-based graft copolymer to an unstretched or uniaxially stretched base polyamide film and drying, the film is uniaxially or uniaxially stretched. The gas barrier film according to claim 4, wherein the gas barrier film is a layer formed by stretching at a higher temperature and heat setting. 8. The method according to claim 1, wherein the inorganic vapor-deposited layer is a layer containing silicon oxide and aluminum oxide.
8. The gas barrier film according to any one of items 1 to 7. 9. The gas barrier film according to claim 8, wherein the content of aluminum oxide in the inorganic vapor deposition layer is 5% by weight or more and 45% by weight or less. 10. The gas barrier film according to claim 1, wherein a heat seal layer made of a composition containing a polyolefin resin is formed on the inorganic vapor-deposited layer.