JP2000238218A - Easy-to-adhere polyamide film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an easy-to-adhere polyamide film excellent in dimensional stability and also excellent in adhesiveness under a wet condition without damaging bending fatigue resistance and transparency. SOLUTION: An adhesion modified layer comprising a resin compsn. based on a self-crosslinkable polyester graft copolymer wherein at least one polymerizable unsaturated monomer containing an acid anhydride having a double bond is grafted to a hydrophobic polyester resin is laminated to at least the single surface of a substrate film wherein an X-layer based on at least one aliphatic polyamide resin selected from the group consisting of nylon 6 and nylon 66 and a Y-layer based on at least one aliphatic polyamide resin selected from the group consisting of nylon 12, nylon 612 and nylon 6/12 form layered constitution of X/Y or Y/X/Y.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an easily adhesive polyamide film having excellent dimensional stability without impairing bending fatigue resistance and transparency, and further having excellent adhesiveness under wet conditions.

[0002]

2. Description of the Related Art Conventionally, polyamide resin films have excellent mechanical properties including toughness and bending resistance, optical properties, thermal properties, gas barrier properties, etc., and are therefore used in various applications including packaging. Widely used for Of which
For example, when used as a packaging bag, generally, an adhesive modification layer is generally provided on at least one surface of a biaxially stretched polyamide film, and if necessary, a printing or organic barrier layer, an inorganic or metal vapor-deposited layer is applied, and further adhesion A laminate of polyamide film is formed by providing a sealant layer by a dry lamination method or an extrusion lamination method on the agent layer, a bag is formed using the laminate, and after filling the contents, the opening is heated. Sealed products are provided to general consumers by packaging, for example, seasonings such as miso and soy sauce, water-containing foods such as soups and retort foods, and chemicals.

[0003]

However, the above-mentioned conventional polyamide film has a drawback that it has a high hygroscopicity due to the characteristics of the polyamide resin itself and a large dimensional change of the base polyamide film due to moisture absorption. When moisture infiltrates each layer of the body, each layer cannot follow the dimensional change of the base film, the adhesive strength between the layers is remarkably reduced, and when used as a packaging bag, it causes breakage of the bag. For example, when retort food is subjected to boiling water treatment or retort treatment, the bag is more easily broken.

[0004] By the way, many materials have been proposed as the adhesion modifying layer material. Among them, it has been proposed to use a water-soluble or water-dispersible polyester resin or acrylic resin for a film having a relatively high polarity mainly of polyester (Japanese Patent Application Laid-Open No. 54-43).
017, JP-B-49-10243, JP-A-52-19786, JP-A-52-19787, and the like. However, when these are applied to a polyamide film, the polyester resin has a drawback that blocking tends to occur when the film is wound into a roll, and the acrylic resin has a drawback of poor adhesion. Therefore, for the purpose of remedying these drawbacks, it has been proposed to use a mixture of the above-mentioned polyester resin and the above-mentioned acrylic resin (JP-A-58-12).
No. 4651), however, it is hard to say that the improvement of the defect is sufficient.

[0005] Further, it has been proposed to use various modified polyesters mainly for graft modification. For example, JP-A-2-3307 and JP-A-2-17124
No. 3, JP-A-2-310048 discloses that a resin obtained by grafting an unsaturated bond-containing compound to a water-soluble or water-dispersible hydrophilic group-containing polyester resin is suitable as a primer for a polyester film. ing. However, the graft modification of a resin in which a hydrophilic group is previously contained in a polyester resin by copolymerization or the like does not have a high degree of adhesion and water resistance.

Japanese Patent Application Laid-Open Nos. 3-273015 and 3-67626 also disclose that a polyester-modified resin is useful as a primer for a polyester film. However, when these resins are used in a polyamide film, their cohesive strength is poor. Therefore, the adhesiveness in a dry state is improved, but the adhesiveness in a wet state is poor. At present, there are problems such as peeling of the film and scratching as the processing is performed.

The present invention has been made to solve the above-mentioned drawbacks, and has as its object to provide excellent dimensional stability without impairing bending fatigue resistance and transparency, and excellent adhesiveness even under wet conditions. An object of the present invention is to provide an easily adhesive polyamide film.

[0008]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present invention shows that a specific polyamide resin having low water absorption and a relatively high impact resistance and bending pinhole resistance were originally obtained. By using a base film laminated with a good specific aliphatic polyamide resin, it is excellent in transparency and dimensional stability without impairing impact resistance, and further forms an adhesion modified layer consisting of a specific composition As a result, the present inventors have found that they have a high adhesive strength even when wet, and have reached the present invention. That is, the present invention is as follows.

(1) An X layer mainly composed of at least one aliphatic polyamide resin (A) selected from the group consisting of nylon 6 and nylon 66, and nylon 12, nylon 612 and nylon 6/12 copolymer A Y layer containing at least one aliphatic polyamide resin (B) selected from the group consisting of X / Y or Y / X /
Self-crosslinkable polyester system in which at least one or more polymerizable unsaturated monomers containing an acid anhydride having a double bond to a hydrophobic polyester resin are grafted on at least one surface of a base film having a layer structure of Y An easily-adhesive polyamide film, wherein an adhesion-modified layer comprising a resin composition containing a graft copolymer as a main component is laminated. (2) The easily adhesive polyamide film as described in (1) above, wherein the polymerizable unsaturated monomers are maleic anhydride and styrene. (3) The ratio of the water absorption (b) of the aliphatic polyamide resin (B) to the water absorption (a) of the aliphatic polyamide resin (A), (b)
/ The easily adhesive polyamide film according to (1), wherein (a) is 0.5 or less. (4) The adhesion-modified layer is coated with a coating solution containing a self-crosslinkable polyester-based graft copolymer on an unstretched or uniaxially stretched base film, and dried, and then the film is uniaxially or more. The easily adhesive polyamide film according to the above (1), which is a layer formed by stretching and heat setting.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The easily adhesive polyamide film of the present invention is obtained by laminating an adhesion modifying layer having a specific composition on at least one surface of a specific base film.

(Base Film) In the present invention, the base film is composed of an X layer mainly composed of an aliphatic polyamide resin (A) and a Y layer mainly composed of an aliphatic polyamide resin (B).
The layer is a film having a layer configuration of X / Y or Y / X / Y.

The aliphatic polyamide resin (A) is originally nylon 6 having relatively good impact resistance and flex pinhole resistance.
And / or nylon 66, and the aliphatic polyamide resin (B) is nylon 12, nylon 612, nylon 6/66 copolymer, nylon 6/12
At least one selected from the group consisting of copolymers.

In the present invention, the ratio (b) / (a) of the water absorption (b) of the aliphatic polyamide resin (B) to the water absorption (a) of the aliphatic polyamide resin (A) is preferable. Is 0.5 or less, more preferably 0.3 or less, particularly preferably 0.2 or less. When this ratio exceeds 0.5,
When the easily adhesive polyamide film of the present invention is used, for example, as a food packaging bag, the dimensional change of the X layer after a heat treatment such as a boil treatment or a retort treatment is large, which causes a bag break. Needless to say, the selection of the aliphatic polyamide resin (A) and the aliphatic polyamide resin (B) depends on the ratio (b) /
(A) is preferably performed so as to be 0.5 or less.

The base film is X / Y or Y / X / Y
When the water absorption ratio of the resin constituting each layer is in the above range, the dimensional change due to water absorption of the base material is small and stable, and therefore, the easy-adhesive polyamide film using such a base film is used. It is considered that even if the packaging bag is boiled or retorted, the bag is not easily broken. In addition, since the aliphatic polyamide resin is used as a component of the X layer and the Y layer, the strength of the easily adhesive polyamide film against drop impact and bending is large.

In the present invention, the base film may contain a flex fatigue resistance improving agent from the viewpoint of further improving the flex resistance. Examples thereof include block polyester amide, block polyether amide, and polyether amide. Examples thereof include elastomers such as ether ester amide-based elastomers, polyester-based elastomers, modified ethylene propylene rubber, and modified acrylic, and ethylene / acrylate copolymers. The flex fatigue resistance improving agent may be contained in either the X layer or the Y layer, or may be contained in both.

In the present invention, in order to prevent blocking between the films and to improve the slipperiness, an appropriate amount of a slipperiness imparting agent such as a particle lubricant or an organic lubricant may be added to the base film. . As the particle-based lubricant, for example,
Examples include inorganic fine particles such as silica, alumina and calcium carbonate, and organic fine particles such as crosslinked acrylic particles and crosslinked polystyrene particles. Further, as an organic lubricant, for example,
Examples include higher fatty acid amides such as stearic acid amide, behenic acid amide, erucic acid amide, N-stearyl stearic acid amide, ethylenebisbenoic acid amide and ethylenebisstearic acid amide, fatty acid metal salts, and fatty acid esters. The particle lubricant and the organic lubricant may be used alone or in some cases, may be used in combination. These particulate lubricants and organic lubricants may be added to either one of the X layer and the Y layer, or both.

The above-mentioned particulate lubricant and organic lubricant are preferably contained in the base film in an amount of 0.05 to 1.0% by weight, more preferably 0.15 to 0.7% by weight. If the content is less than 0.05% by weight, the lubricity of the film tends to be insufficient, and if it exceeds 1.0% by weight, the transparency of the base film tends to be poor. In the present invention, one or more of the above-mentioned particle-based lubricants and organic lubricants may be used. Further, a particulate lubricant and an organic lubricant may be used in combination. 2
Combined use of more than one kind of particulate lubricant and organic lubricant,
This is a preferred embodiment for balancing transparency and lubricity, and is a recommended method for blending fine particles.

In the present invention, the average particle diameter of the particulate lubricant and / or the organic lubricant is 0.5 to 5.0 μm,
In particular, it is preferable to use one having a thickness of 1.0 to 4.0 μm. If the average particle diameter is less than 0.5 μm, sufficient lubricity cannot be imparted to the base film, while if it exceeds 5.0 μm, the transparency of the base film becomes poor or the halftone printability deteriorates. .

In the present invention, various additives may be further added to the base film as long as the purpose and performance are not impaired. For example, antioxidants, light stabilizers, gelling inhibitors, lubricants, organic lubricants Agents, pigments, antistatic agents, surfactants, and the like.

The substrate film can be manufactured by a known manufacturing 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, a known method such as a tenter-type successive biaxial stretching method, a tenter-type simultaneous biaxial stretching method, and a tubular method can be used. The thickness ratio between the X layer and the Y layer in the base film is not particularly defined.

(Adhesion-Modified Layer) The easily adhesive polyamide film of the present invention is obtained by laminating an adhesion-modified layer on at least one surface of the above-mentioned base film. The resin composition comprises a self-crosslinkable polyester-based graft copolymer obtained by grafting at least one or more polymerizable unsaturated monomers onto a polyester resin. 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 term "adhesiveness" as used in the present invention means that the adhesiveness at the time of peeling with 90 ° water is 200 g / 15 mm or more. It is preferably at least 250 g / 15 mm, particularly preferably at least 300 g / 15 mm.

Hydrophobic polyester 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. When a polyester resin that disperses or dissolves in water is used for graft polymerization, the adhesiveness and water resistance of the easily adhesive polyamide film of the present invention deteriorate.

The dicarboxylic acid component of the hydrophobic polyester resin is 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%
When it exceeds, the adhesive strength of the easily adhesive polyamide film of the present invention 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 the 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. If a hydrophilic-containing dicarboxylic acid such as 5-sodium sulfoisophthalic acid is used, the water resistance of the adhesion-modified layer is reduced. As the aliphatic dicarboxylic acid, for example, succinic acid, adipic acid, azelaic acid,
Sebacic acid, dodecanedicarboxylic acid, dimer acid and the like can be mentioned. As the alicyclic dicarboxylic acid, for example, 1,
Examples thereof include 4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, and acid anhydrides thereof.

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

The amount of the hydrophobic polyester resin is from 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 trifunctional or higher polycarboxylic acids include trimellitic anhydride (anhydride),
(Anhydride) pyromellitic acid, (anhydride) benzophenonetetracarboxylic acid, trimesic acid, ethylene glycol bis (anhydrotrimellitate), 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 copolymerized preferably in the range of 0 to 5 mol%, more preferably in the range of 0 to 3 mol%, in the total dicarboxylic acid component or the total glycol component.
If it exceeds 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 weight average molecular weight. If the molecular weight is less than 5,000, the adhesive strength of the easily adhesive polyamide film of the present invention may be reduced, while if it exceeds 50,000, problems such as gelation during polymerization may occur.

Polymerizable unsaturated monomer Examples of the polymerizable unsaturated monomer graft-polymerized on the hydrophobic polyester resin include fumaric acid; fumaric acid such as monoethyl fumarate, diethyl fumarate and dibutyl fumarate. Monoesters or diesters; maleic acid and anhydrides; monoesters or diesters of maleic acid such as monoethyl maleate, diethyl maleate, dibutyl maleate; itaconic acid and anhydrides; monoesters or diesters of itaconic acid Maleimides such as phenylmaleimide; styrene derivatives such as styrene, α-methylstyrene, t-butylstyrene, chloromethylstyrene, vinyltoluene and divinylbenzene;
Examples of the acrylic polymerizable monomer include, for example, alkyl (meth) acrylate (where the alkyl group is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl) Group, cyclohexyl group, phenyl group, benzyl group, phenylethyl group, etc.); hydroxy group-containing (meth) acryl such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, etc. Acrylamide, methacrylamide, N-methylmethacrylamide, N-methylacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N, N-dimethylolacrylamide, N-methoxymethylacrylamide Group-containing (meth) acrylic monomers such as N, N-methoxymethyl methacrylamide and N-phenylacrylamide; amino group-containing (meth) acrylic monomers such as N, N-diethylaminoethyl acrylate and N, N-diethylaminoethyl methacrylate Epoxy group-containing (meth) acrylic monomers such as glycidyl acrylate and glycidyl methacrylate; acrylic acid, methacrylic acid and salts thereof (sodium salt,
Carboxyl group-containing (meth) acrylic monomers such as potassium acid and ammonium salt). The above monomers can be copolymerized by using one kind or two or more kinds. In the present invention, it is necessary to use an acid anhydride having at least a double bond as the polymerizable unsaturated monomer, whereby an easily adhesive polyamide film having excellent adhesiveness is obtained. As the acid anhydride having such a double bond, maleic anhydride is preferable among the above examples. It is particularly preferable to use styrene and maleic anhydride in combination from the viewpoint of preventing gelation in the polymerization process.

Graft copolymer In the graft copolymer, the weight ratio of the hydrophobic polyester resin and the polymerizable unsaturated monomer, that is, the ratio of the hydrophobic polyester resin / polymerizable unsaturated monomer is preferably 40/60 to
95/5, more preferably 55/45 to 93/7, 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. When the acid value is less than 600 equivalents / 10 ⁶ g, the adhesiveness of the easily adhesive polyamide film of the present invention 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 water-dispersed graft copolymer is a water-dispersible resin, the weight average molecular weight of the polymer component of the polymerizable unsaturated monomer, which is a branch polymer in the graft copolymer, is from 500 to 50,000. Is preferred. The weight average molecular weight of the polymer component is 500
In general, it is difficult to control the amount below, 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-mentioned water-dispersed resin can be obtained in various particle sizes by a polymerization method. It is appropriate that the average particle size measured by a laser light scattering method is 10 to 500 nm. The thickness is preferably 400 nm or less, more preferably 300 nm or less, from the viewpoint of properties. 500
If the thickness exceeds 500 nm, the film-forming property decreases and the coating film becomes non-uniform, and the surface of the formed adhesion reforming layer decreases in transparency due to a decrease in gloss. Water resistance may be poor, which is not preferred.

In order to obtain a 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 that dissolves the hydrophobic polyester resin well and 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 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 that 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 performed 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 chains 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, and more preferably 90/90.
/ 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. Ariiso peroxide includes benzoyl peroxide, t-butylperoxypivalate, and the like, and organic azo compounds 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
It is desirable that this is the case.

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, and the adhesiveness, water resistance, and hot water resistance of the easily adhesive polyamide film of the present invention are excellent. Becomes

In the present invention, a 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. Thereby, the adhesiveness and water resistance of the easily adhesive polyamide film of the present invention can be expressed for the first time. 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 cross-linking agent (curing resin) and curing, the adhesion-modified layer can have a 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.

Examples of the phenol formaldehyde resin include, 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, butoxylated methylol benzoguanamine and the like. And preferably methoxylated methylolmelamine, butoxylated methylolmelamine, methylolated benzoguanamine and the like.

Examples of the polyfunctional epoxy compound include diglycidyl ether of bisphenol A and oligomers thereof, diglycidyl ether 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, polyalkylene glycol diglycidyl ethers, triglycidyl trimellitate, triglycidyl isocyanate Nurate, 1,
4-glycidyloxybenzene, diglycidyl propylene urea, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol triglycidyl ether, triglycidyl ether of glycerol alkylene oxide adduct and the like.

As the polyfunctional isocyanate compound,
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 copolymer can form an adhesion-modified layer as it is, but for other purposes, general-purpose polyester resins, urethane resins, acrylic resins, copolymers thereof, various water-soluble resins, etc. And various functional resins (for example, conductive resins such as polyaniline and polypyrrole, antibacterial resins, ultraviolet-absorbing resins, and gas-barrier resins) 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 is carried out by preparing a solution or dispersion of an organic solvent 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. This is carried out by coating and drying the 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, a known method such as a gravure method, a reverse method, a die method, a bar method, and a dip method is 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 adhesive strength of the easily adhesive polyamide film of the present invention 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 thermal degradation does not occur in the base film and the graft copolymer, it is preferable to increase the amount of heat. Specifically, 80 ° C to 250 ° C, more preferably 150 ° C to 2
20 ° C. However, by increasing the drying time,
It is not limited to the above conditions, since sufficient self-crosslinking property is exhibited even at a relatively low temperature.

When the above-mentioned coating solution is applied to an unstretched or uniaxially stretched base film and dried, and then the film is stretched uniaxially or more, the drying temperature after application is within a range not affecting the subsequent stretching. In the case of a base film, the film is stretched with the moisture content of the film being 2% or less, and then heat-fixed at 200 ° C. or more to make the film strong, Adhesion with the base 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-mentioned coating liquid is applied to the biaxially stretched base film, the base film is formed before the formation of the adhesion modified layer in order to further improve the adhesion between the base film and the adhesion modified layer. Surface treatment such as corona treatment, flame treatment, and electron beam irradiation may be performed.

Although the adhesion-modified layer has good adhesion to various materials, when forming a layer on the adhesion-modified layer, in order to further improve the adhesion, the adhesion-modified layer is further added to the adhesion-modified layer in advance. Surface treatment such as treatment, flame treatment, and electron beam irradiation may be performed.

When the easily adhesive polyamide film of the present invention is used as a packaging material, a sealant layer made of a polyolefin resin for providing thermal adhesion is formed on the adhesion modifying layer. As the polyolefin resin,
For example, LDPE, LLDPE, CPP and the like are exemplified. The sealant layer does not necessarily have to be a single layer and may be a multilayer.When forming a multilayer structure, the resin constituting each layer may be a combination of the same type of resin, a copolymer of a different polymer or a modified polymer. Products, blends and the like may be laminated. For example, a polymer having a glass transition temperature (Tg) or a melting point lower than that of a thermoplastic polyolefin resin as a base is blended in order to enhance laminating properties or sealant properties, or a Tg or a melting point having a high melting point is added to impart heat resistance. It is also possible to incorporate polymers.

In the sealant layer, if necessary, various additives such as a plasticizer, a heat stabilizer, an ultraviolet absorber, an antioxidant, a coloring agent, a filler, an antistatic agent, an antibacterial agent, a lubricant, and an anti-blocking agent. It is also possible to blend agents and other resins.

The sealant layer is formed on the adhesion-modified layer by a dry lamination method or a wet lamination method using an adhesive, or by a melt extrusion lamination method or a coextrusion lamination method.

When the packaging material is subjected to a heat treatment such as a boil treatment or a retort treatment, for example, an inorganic vapor-deposited layer is formed between the adhesion modifying layer and the sealant layer. The inorganic vapor-deposited layer contains silicon oxide, aluminum oxide, magnesium oxide, a mixture thereof, or the like. The inorganic vapor-deposited layer containing a mixture of aluminum oxide and silicon oxide is particularly preferable because it 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). 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.

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 forming the inorganic vapor-deposited layer, a physical vapor-deposition method such as a vacuum vapor-deposition method, a sputtering method, 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 thus obtained easily adhesive polyamide film of the present invention includes miso, pickles, side dishes, baby food, boiled tsukudani, konjac, chikuwa, kamaboko, processed fishery products, meatballs, hamburgers, genghis khan, ham, sausage,
Other processed meat products, tea, coffee, black tea, bonito, kelp, potato chips, butter peanuts and other oil confections, rice crackers, biscuits, cookies, cakes, buns, castella,
Cheese, butter, rice cake, soup, sauce, ramen,
It can be effectively used as a food material such as wasabi and a packaging material for toothpaste and the like, and can be used for pet food, pesticides, fertilizers,
The present invention can be effectively used for infusion packs, packaging materials for semiconductors and precision materials, and packaging materials for industrial materials such as medical, electronic, chemical, and mechanical devices.

There is no particular limitation on the form of the packaging material.
It can be widely applied to bags, lid materials, cups, tubes, standing packs and the like.

[0073]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples. However, the present invention is not limited to the following examples, and appropriate modifications may be made without departing from the scope of the present invention. All of them are included in the technical scope of the present invention. In addition, the measurement of the characteristic value in this specification followed the following method.

1. Adhesive property Regarding a laminated film having a sealant layer provided on the surface of an adhesion-modified layer (including a case where an inorganic vapor-deposited layer is provided on the surface of the adhesion-modified layer) of an easily-adhesive polyamide film, "Tensilon UTM2" manufactured by Toyo Sokki Co., Ltd. , A peeling portion was provided in advance at the interface between the adhesion reforming layer and the sealant layer, and was fixed to a Tensilon chuck. 90 ° peeling was performed while attaching water to the interface, and the adhesion was evaluated from the SS curve between the adhesion modifying layer and the sealant layer (unit: g / 15 mm). 20
If it was 0 g / 15 mm or more, the adhesiveness was judged to be good.

2. Water absorption ratio With respect to the aliphatic polyamide resins (A) and (B) constituting the X layer and the Y layer of the base film, the resins (A) and (B) were each formed into a single-layer film, and each was subjected to ASTM D.
After immersion in 23 ° C. water for 24 hours according to 570, the water absorption (a) and (b) were determined from the weight before and after immersion, and (b) / (a) was calculated from the values.

3. Dimensional change The dimensional change due to the humidity expansion of the base film was measured for the hygroscopic dimensional elongation by a combination of a thermal stress / strain measuring device TMA (manufactured by Vacuum Riko Co., Ltd.) and a gas humidifier. Cut a sample of base polyamide film into 50mm length and 4mm width TM
Set in device A. 80% RH → 35% RH → 73% RH →
The relative humidity was changed 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 film from the change in humidity to the time: x1
(%) Elongation in the width direction of the base film when the humidity changes to when: x2
(%) Humidity change from time to time: y1 (%) Humidity change from time to time: y2 (%) From these values, the elongation in the width direction of the base film per 60% of humidity is calculated by the following formula. Calculated. 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. Note that the “width direction” of the base film refers to a direction orthogonal to the flow direction of the film.

4. Bending Fatigue Resistance Test The bending fatigue resistance test of the easily adhesive polyamide film was evaluated by the following method using a gelbo flex tester manufactured by Rigaku Corporation. The other end was fixed to the fixed head side having a diameter of 3.5 inches and the movable head side, and the initial gripping interval was set to 7 inches. The first 3.5 inches of the stroke gives a 440 degree twist, followed by 2.5 inches of flex fatigue that completes the entire stroke in a linear horizontal motion.
The number of pinholes generated in the film was counted 1000 times at a speed of times / minute to count the number of pinholes generated in the film. The measurement was performed in an environment of 25 ° C., and the number of holes generated in the film was determined to be good when the number of holes was 20/7 inch square or less.

5. Transparency For easily adhesive polyamide film, JIS-K67
According to No. 14, the haze value was measured with a haze tester at Toyo Seiki Seisakusho. Those having a haze value of 5.0% or less were evaluated as having good transparency.

(Preparation of Hydrophobic Polyester Resin A-1)
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, 270 parts by weight of ethylene glycol 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 16 parts of sebacic acid
0 part by weight was added, and the temperature was raised from 200 ° C. to 220 ° C. over 1 hour to carry out an esterification reaction. Next, the temperature was raised to 255 ° C., and the pressure of the reaction system was gradually reduced.
The reaction was carried out for 1 hour and 30 minutes under reduced pressure to obtain a hydrophobic polyester resin (A-1). The obtained polyester was pale yellow and transparent.

The weight average molecular weight measured by NMR is 200
And 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 B-1 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 a hydrophobic polyester resin (A-1) and 56 parts by weight of methyl ethyl ketone Parts and 19 parts by weight of isopropyl alcohol, and heated and stirred at 65 ° C.,
The resin was dissolved. After the resin is completely dissolved, maleic anhydride 1
5 parts by weight were 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, followed by stirring for 1 hour. Thereafter, the reactor internal temperature was raised to 100 ° C., and methyl ethyl ketone, isopropyl alcohol, and excess ammonia were distilled off to obtain a water-dispersed graft copolymer (B-1). The water-dispersed graft copolymer (B-1) was pale yellow and transparent. The water-dispersed graft copolymer (B-1)
Was diluted with water: isopropyl alcohol = 9: 1 (weight ratio) to a solid concentration of 10% to prepare a coating solution.

[0082]Example 1 100 parts by weight of nylon 6 as the X layer and nylon 6 as the Y layer
Ron 12 (manufactured by Daicel Huls, Daiamide L194)
0) Layer composition of Y layer / X layer / Y layer using 100 parts by weight
And the thickness ratio is Y layer: X layer: Y layer = 1.5: 7.0:
Melt co-extrusion and lamination at 1.5 on a rotating drum at 20 ° C
To obtain an unstretched film having a thickness of 180 μm. This
Was stretched 3.0 times at 50 ° C. Next
The above water-dispersed graft copolymer (B-1) -containing coating
Apply liquid by die coater method and dry with hot air at 70 ° C
And then stretched 4.0 times in the transverse direction at 125 ° C.
15 ℃ biaxially stretched coating
A polyamide film was obtained. Final water dispersion graft
The coating amount of the coating liquid containing the copolymer (B-1) is 0.1 g / m.
^TwoMet.

Example 2 A biaxially stretched coated polyamide film was obtained in the same manner as in Example 1 except that 100 parts by weight of nylon 6/12 was used as the Y layer.

Example 3 In Example 1, the thickness of each layer of the polyamide film having the layer structure of Y layer / X layer / Y layer was set as follows: Y layer: X layer: Y layer = 0.5:
A biaxially stretched coated polyamide film was obtained in exactly the same manner as in Example 1 except that the ratio was set to 9.0: 0.5.

Example 4 In Example 2, the thickness of each layer of the polyamide film having the layer structure of Y layer / X layer / Y layer was set as follows: Y layer: X layer: Y layer = 0.5:
Except having set it to 9.0: 0.5, it carried out exactly like Example 2, and obtained the biaxially stretched coating polyamide film.

(Preparation of Graft Copolymer B-2 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 a hydrophobic polyester resin (A-1) and 56 parts by weight of methyl ethyl ketone Parts and 19 parts by weight of isopropyl alcohol, and heated and stirred at 65 ° C.,
The resin was dissolved. After the resin is completely dissolved, methacrylic acid 1
A mixture of 7.5 parts by weight of ethyl acrylate and 7.5 parts by weight of ethyl acrylate, and a solution of 1.2 parts by weight of azobisdimethylvaleronitrile dissolved in 25 parts by weight of methyl ethyl ketone are dropped into the polyester solution at 0.2 ml / min. Then, stirring was further continued for 2 hours. After sampling for analysis from the reaction solution, 300 parts by weight of water and 25 parts by weight of triethylamine were added to the reaction solution and stirred for 1 hour. Thereafter, the reactor internal temperature was raised to 100 ° C., and methyl ethyl ketone, isopropyl alcohol, and excess triethylamine were distilled off, and the water-dispersed graft copolymer (B-
2) was obtained. The water-dispersed graft copolymer (B-2) was pale yellow and transparent. The water-dispersed graft copolymer (B
-2) was diluted with water: isopropyl alcohol = 9: 1 (weight ratio) to a solid concentration of 10% to prepare a coating solution.

Comparative Example 1 In Example 1, the water-dispersed graft copolymer (B-1)
Water-dispersed graft copolymer (B-
2) Except that the containing coating solution was used, the same procedure as in Example 1 was carried out to obtain a biaxially stretched coated polyamide film.

Comparative Example 2 A biaxially stretch coated polyamide film was obtained in the same manner as in Example 1, except that 100 parts by weight of nylon 6 were used for both the X layer and the Y layer.

Comparative Example 3 Biaxial stretching was performed in the same manner as in Example 1, except that the coating liquid containing the water-dispersed graft copolymer (B-1) was not applied to the base film. A coated polyamide film was obtained.

The biaxially stretched coated polyamide films obtained in Examples 1 to 4 and Comparative Examples 1 to 3 were evaluated. Table 1 shows the results.

[0091]

[Table 1]

From Table 1, it can be seen that the biaxially stretched coated polyamide films obtained in Examples 1 to 4 have good transparency, bending fatigue resistance and adhesiveness, and have little dimensional change of the base film. You can see that there is.

[0093]

As is clear from the above description, the easily adhesive polyamide film of the present invention is obtained by forming an adhesion-modified layer having a specific composition on a specific substrate film by using a predetermined polyester-based graft copolymer. It has excellent dimensional stability and excellent adhesion under wet conditions without sacrificing bending fatigue resistance and transparency, and is particularly laminated on the adhesion modified layer by dry lamination or extrusion lamination. It has excellent adhesion to sealant materials and thin films of metals, inorganic substances or oxides thereof, and can significantly reduce bag breakage due to retort treatment or boiling water treatment of the laminate.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tadashi Sugimoto 2-1-1 Katata, Otsu City, Shiga Prefecture Inside Toyobo Co., Ltd. Research Institute (72) Inventor Masazumi Imanishi 2-1-1 Katata, Otsu City, Shiga Prefecture No. Toyobo Co., Ltd. Research Laboratory (72) Inventor Shigeru Yoneda 2-1-1 Katata, Otsu-shi, Shiga F-term in Toyobo Co., Ltd. Research Laboratory 4D075 CA03 CA40 DA04 DB53 DC36 EA35 EB35 4F006 AA38 AB35 AB52 BA01 CA07 DA04 EA05 EA06 4F100 AK12D AK12J AK24D AK24J AK41D AK48A AK48B AK48C AL04D BA03 BA04 BA06 BA10A BA10C BA10D BA26 EH20 EH202 EH46 EH462 EJ05D EJ38 EJ382 GB17 J04B08J17 JB06D08 J17

Claims (4)

[Claims] 1. An X layer comprising at least one aliphatic polyamide resin (A) as a main component selected from the group consisting of nylon 6 and nylon 66, and nylon 12, nylon 612 and nylon 6/12 copolymer. At least one aliphatic polyamide resin (B) selected from the group consisting of X / Y or Y / X /
Self-crosslinkable polyester system in which at least one or more polymerizable unsaturated monomers containing an acid anhydride having a double bond to a hydrophobic polyester resin are grafted on at least one surface of a base film having a layer structure of Y An easily-adhesive polyamide film, wherein an adhesion-modified layer comprising a resin composition containing a graft copolymer as a main component is laminated. 2. The easily adhesive polyamide film according to claim 1, wherein the polymerizable unsaturated monomers are maleic anhydride and styrene. 3. The ratio of the water absorption (b) of the aliphatic polyamide resin (B) to the water absorption (a) of the aliphatic polyamide resin (A), wherein (b) / (a) is 0.5 or less. The easily adhesive polyamide film according to claim 1, wherein: 4. A coating solution containing a self-crosslinkable polyester-based graft copolymer in which an adhesion modifying layer is applied to an unstretched or uniaxially stretched base film and dried. The easy-adhesive polyamide film according to claim 1, which is a layer formed by stretching and heat-setting as described above.