JPH11179867A - Laminated polyamide film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated polyamide film having an excellent adhesive properties and a water resistance. SOLUTION: In the laminated polyamide film comprising a layer containing a self-crosslinkable polyester graft copolymer grafted from at least one type or more of polymerizable unsaturated monomers with a hydrophobic polyester resin as a constituent on at least one side surface of a polyamide base material film, the monomer contains at least one type of monomer containing an acid anhydride having a doublebond in the unsaturated monomer. And, a glass transition temperature of the graft copolymer is 30 deg.C or lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide film having improved adhesiveness, and is intended for use in a wide range of applications such as an adhesive at the time of lamination, a thin film of metal or inorganic or oxides thereof. The present invention is to provide a polyamide film having water resistance and boil resistance.

[0002]

2. Description of the Related Art Biaxially stretched polyamide films are made of tough,
It has excellent pinhole resistance, bending resistance, heat resistance, etc., and is widely used for various applications. Among them, for example, when using a polyamide film as a packaging bag, generally, if necessary, at least one side of the biaxially stretched polyamide film is subjected to printing or an organic barrier layer, an inorganic or metal deposition layer, and further provided with an adhesive. On top, a sealant layer is provided by a dry lamination method, or a sealant layer is provided by an extrusion lamination method to form a laminate of a polyamide film, a bag is prepared using the laminate, and the contents are filled and the opening is formed. Is heat-sealed and packaged with seasonings such as miso and soy sauce, water-containing foods such as soups and retort foods, or chemicals, and provided to general consumers.

[0003]

However, when moisture enters the layers forming the biaxially stretched polyamide film laminate, 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. In addition, as packaging products become more sophisticated, multi-color printing becomes widespread, and various problems occur due to the presence of the printing ink layer. Also, when an adhesive layer is interposed between the biaxially stretched polyamide film layer and the sealant layer, some types of adhesive are susceptible to the adhesive force due to humidity, and in particular, in the case of a moisture-curable adhesive, The effect is remarkable, and the seasonal adhesive strength fluctuates greatly. Therefore, in the present invention, a polyamide film laminate having good adhesion between the layers in the polyamide film laminate and maintaining high adhesion even when wet was studied. The dimensional change of the polyamide film due to moisture absorption was several percent, and it was found that when an inorganic or metal vapor-deposited layer was laminated, the vapor-deposited layer could not follow the dimensional change of the polyamide film and was easily peeled off.

[0004] Numerous materials have been proposed as coating agents. Among them, a water-soluble or water-dispersible polyester resin or acrylic resin is used for a film having relatively high polarity, mainly polyester. It has been proposed. (Japanese Patent Laid-Open No. 54-43017, Japanese Patent Publication No. 49-1
0243, JP-A-52-19786, JP-A-52-19787, etc.) However, when these are applied to a polyamide film, the polyester-based resin is liable to cause blocking when the film is rolled into a roll. There is a disadvantage that the acrylic resin has poor adhesion to the film and the layer coated with the primer layer. Therefore, for the purpose of improving these disadvantages, it has been proposed to use a mixture of the polyester resin and the acrylic resin (Japanese Patent Application Laid-Open No. 58-124651). hard. Further, it has been proposed to use various modified polyesters mainly for graft modification. For example, JP-A-2-3307, JP-A-2-117243, JP-A-2-310048, the resin obtained by grafting an unsaturated bond-containing compound to a water-soluble or water-dispersible hydrophilic group-containing polyester resin is a polyester. It is disclosed that it is suitable as a film primer. 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. Also, JP-A-3-273015,
No. 67626 also discloses that polyester-modified resins are useful as polyester film primers. 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 becomes. An object of the present invention is to provide a laminated polyamide film having excellent adhesiveness, water resistance, solvent resistance, and blocking resistance, with the object of solving the above problems.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a self-crosslinkable polyester graft in which at least one surface of a polyamide base film is grafted with at least one polymerizable unsaturated monomer on a hydrophobic polyester resin. A laminated polyamide film having a layer containing a copolymer as a constituent component, wherein the polymerizable unsaturated monomer contains at least one monomer containing an acid anhydride having a double bond. The above object can be achieved by a laminated polyamide film. In a preferred embodiment of the present invention,
The layer containing the self-crosslinkable polyester-based graft copolymer as a component, a coating solution containing the self-crosslinkable polyester-based graft copolymer is applied to an unstretched or uniaxially stretched film, and after drying, the coated film is further treated. The laminated polyester film according to claim 1, which is formed by heat-setting after stretching uniaxially or more. In a further preferred embodiment of the present invention, the polyester-based graft copolymer has a glass transition point of 30 ° C. or lower. In a further preferred embodiment of the present invention, the polymerizable unsaturated monomer contains at least a combination of maleic anhydride and styrene.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, "grafting" refers to introducing a branch polymer made of a polymer different from the main chain into the main chain of the main polymer.

(Graft Polymer) In the graft polymerization of the present invention, generally, a radical initiator and a radical polymerizable monomer mixture are reacted in a state where a hydrophobic copolymer polyester resin is dissolved in an organic solvent. It is implemented by. The reaction product after the completion of the grafting reaction is, in addition to the graft polymer between the desired hydrophobic copolymerized polyester-radical polymerizable monomer mixture, the hydrophobic copolymerized polyester that has not been grafted and the hydrophobic copolymerized polyester. It also contains a radical polymer not grafted to the polymerized polyester, but the graft polymer in the present invention includes all of them.

In the present invention, the acid value of a reaction product obtained by graft-polymerizing a radical polymerizable monomer onto a hydrophobic copolymerized polyester resin is preferably at least 600 eq / 10 ⁶ g. More preferably, the acid number of the reactants is 1200 eq
/ 10 ⁶ g or more. The reaction product has an acid value of 600 eq / 1
Is less than 0 ⁶ g, the adhesion between the layer to be coated in a is primed material object of the present invention is not sufficient.

Further, the weight ratio of the desired hydrophobic copolymerized polyester resin and the radical polymerizable monomer suitable for the purpose of the present invention is as follows: polyester / radical polymerizable monomer = 4
The range is preferably 0/60 to 95/5, more preferably 55/45 to 93/7, most preferably 60/40 to 9/9.
It is in the range of 0/10. When the weight ratio of the hydrophobic copolymerized polyester resin is less than 40% by weight, excellent adhesiveness of the polyester resin cannot be exhibited. on the other hand,
95% by weight of hydrophobic copolymerized polyester resin
When it is larger, blocking, which is a drawback of the polyester resin, tends to occur.

The graft polymerization reaction product of the present invention 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,
The form of the water-dispersed resin is preferred in view of working environment and applicability. In order to obtain such a water-dispersed resin, usually, in an organic solvent, the hydrophobic copolymerized polyester resin is graft-polymerized with a radical polymerizable monomer containing a hydrophilic radical polymerizable monomer, This is achieved by adding water and distilling off the organic solvent. The water-dispersed resin of the present invention has an average particle size of 500 nm or less as measured by a laser light scattering method, and exhibits a translucent or milky white appearance. By adjusting the polymerization method, water-dispersed resins having various particle diameters can be obtained. The particle diameter is suitably from 10 to 500 nm, and from the viewpoint of dispersion stability, is preferably 400 nm or less, more preferably 300 nm or less.
nm or less. If it exceeds 500 nm, the gloss of the surface of the coating film is reduced, and the transparency of the coating is reduced.
Below, the water resistance, which is the object of the present invention, is reduced,
Not preferred.

The hydrophilic radically polymerizable monomer used in the polymerization of the water-dispersed resin in the present invention refers to a group having a hydrophilic group or a group which can be converted into a hydrophilic group later. As a radical polymerizable monomer having a hydrophilic group, a carboxyl group, a hydroxyl group, a phosphoric acid group, a phosphorous acid group, a sulfonic acid group, an amide group,
A radical polymerizable monomer containing a quaternary ammonium base or the like can be given. On the other hand, as radical polymerizable monomers that can be converted to hydrophilic groups, acid anhydride groups, glycidyl groups,
Chlorine and the like can be mentioned. Among these, a carboxyl group is preferable from the viewpoint of water dispersibility, and a radical polymerizable monomer having a carboxyl group or a group generating a carboxyl group is preferable. From the viewpoint of increasing the acid value of the present invention, it is preferable that the compound contains a carboxyl group or contains a radical polymerizable monomer that generates a carboxyl group.

The glass transition temperature of the graft copolymer is 3
The temperature is 0 ° C or less, preferably 10 ° C or less. By using a graft copolymer having a glass transition temperature of 30 ° C. or lower for the adhesion modifying layer, a laminated polyester film having particularly excellent adhesion can be obtained.

(Polyester) In the present invention, the hydrophobic copolymerized polyester resin must be essentially water-insoluble and does not originally disperse or dissolve in water.
When a polyester resin that disperses or dissolves in water is used for graft polymerization, the adhesiveness and water resistance, which are the objects of the present invention, deteriorate. The composition of the dicarboxylic acid component of the hydrophobic copolyester resin is from 60 to 60 aromatic dicarboxylic acids.
It is preferably 99.5 mol%, 0 to 40 mol% of aliphatic dicarboxylic acid and / or alicyclic dicarboxylic acid, and 0.5 to 10 mol% of dicarboxylic acid containing a polymerizable unsaturated double bond. When the amount of the aromatic dicarboxylic acid is less than 60% by mole or when the amount of the aliphatic dicarboxylic acid and / or the alicyclic dicarboxylic acid exceeds 40% by mole, the adhesive strength decreases. When the amount of the dicarboxylic acid containing a polymerizable unsaturated double bond is less than 0.5 mol%, efficient grafting of the radical polymerizable monomer to the polyester resin becomes difficult, and conversely, 10 mol% If it exceeds, the viscosity is undesirably increased too late in the late stage of the grafting reaction, preventing uniform progress of the reaction. More preferably, the aromatic dicarboxylic acid is 70 to 98 mol%, the aliphatic dicarboxylic acid and / or the alicyclic dicarboxylic acid is 0 to 30 mol%, and the dicarboxylic acid containing a polymerizable unsaturated double bond is 2 to 98 mol%.
7 mol%. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, and the like. It is preferable not to use a hydrophilic group-containing dicarboxylic acid such as 5-sodium sulfoisophthalic acid from the viewpoint of reducing the water resistance, which is the object of the present invention. As aliphatic dicarboxylic acids, succinic acid, adipic acid, azelaic acid,
Sebacic acid, dodecanedioic acid, dimer acid and the like can be mentioned. Examples of the alicyclic dicarboxylic acid include 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid and its acid. An anhydride and the like can be mentioned. Examples of dicarboxylic acids containing a polymerizable unsaturated double bond include, as α, β-unsaturated dicarboxylic acids, fumaric acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid, and unsaturated double bonds. Examples of the alicyclic dicarboxylic acid include 2,5-norbornene dicarboxylic anhydride and tetrahydrophthalic anhydride. Of these, fumaric acid, maleic acid, and 2,5-norbornene dicarboxylic acid are preferred from the viewpoint of polymerizability. On the other hand, the glycol component
It is composed of an aliphatic glycol having 2 to 10 carbon atoms and / or an alicyclic glycol having 6 to 12 carbon atoms and / or an ether bond-containing glycol. 2-
Propylene glycol, 1,3-propanediol,
1,4-butanediol, 1,5-pentanediol,
Neopentyl glycol, 1,6-hexanediol,
Examples thereof include 3-methyl-1,5-pentanediol, 1,9-nonanediol, and 2-ethyl-2-butylpropanediol. Examples of the alicyclic glycol having 6 to 12 carbon atoms include 1,4. -Cyclohexanedimethanol and the like. Examples of the ether bond-containing glycol include diethylene glycol, triethylene glycol, dipropylene glycol, and glycols obtained by adding ethylene oxide or propylene oxide to two phenolic hydroxyl groups of bisphenols, for example, 2,2-bis (4 -Hydroxyethoxyphenyl) propane and the like. Polyethylene glycol, polypropylene glycol and polytetramethylene glycol can also be used if necessary. In the copolymerized polyester resin used in the present invention, 0 to 5 mol% of a trifunctional or higher functional polycarboxylic acid and / or a polyol can be copolymerized. Anhydrous) trimellitic acid, anhydrous
Pyromellitic acid, (anhydrous) benzophenonetetracarboxylic acid, trimesic acid, ethylene glycol bis (anhydrotrimellitate), glycerol tris (anhydrotrimellitate) and the like are used. On the other hand, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and the like are used as the trifunctional or higher polyol. Trifunctional or higher polycarboxylic acid and / or
Alternatively, the polyol is copolymerized in the range of 0 to 5 mol%, preferably 0 to 3 mol%, based on the total acid component or total glycol component, but if it exceeds 5 mol%, gelation during polymerization is likely to occur, Not preferred. The molecular weight of the hydrophobic copolymerized polyester resin is preferably in the range of 5,000 to 50,000 on a weight average. When the molecular weight is less than 5,000, the adhesive strength is reduced, while when it exceeds 50,000, problems such as gelation during polymerization occur.

(Polymer containing polymerizable unsaturated monomer) The polymerizable unsaturated monomer of the present invention is, for example, a monomer of fumaric acid such as fumaric acid, monoethyl fumarate, diethyl fumarate and dibutyl fumarate. Ester or diester 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,
Styrene derivatives such as α-methylstyrene, t-butylstyrene, and chloromethylstyrene; vinyltoluene; divinylbenzene; The acrylic polymerizable monomer includes, for example, alkyl acrylate, alkyl methacrylate (the alkyl group is a methyl group, an ethyl group,
Propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, cyclohexyl, phenyl, benzyl, phenylethyl, etc.): 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate , 2-hydroxypropyl acrylate, hydroxy-containing acrylic monomers of 2-hydroxypropyl methacrylate: acrylamide, methacrylamide, N-methylmethacrylamide, N-methylacrylamide, N-methylolacrylamide, N
-Methylol methacrylamide, N, N-dimethylolacrylamide, N-methoxymethylacrylamide,
Amide group-containing acrylic monomers of N-methoxymethyl methacrylamide and N-phenylacrylamide: N, N-
Amino group-containing acrylic monomer of diethylaminoethyl acrylate, N, N-diethylaminoethyl methacrylate: glycidyl acrylate, epoxy group-containing acrylic monomer of glycidyl methacrylate: acrylic acid, methacrylic acid and salts thereof (sodium salt, potassium salt, Acrylic monomer containing a carboxyl group such as ammonium salt) or a salt thereof. Preferably,
Maleic anhydride and its esters. The above monomers can be copolymerized by using one kind or two or more kinds.

The graft polymerization of the present invention is generally carried out by reacting a radical initiator and a radical polymerizable monomer mixture in a state where a hydrophobic copolymerized polyester resin is dissolved in an organic solvent. The reaction product after the completion of the grafting reaction is, in addition to the graft polymer between the desired hydrophobic copolymerized polyester-radical polymerizable monomer mixture, the hydrophobic copolymerized polyester that has not been grafted and the hydrophobic copolymerized polyester. It also contains a radical polymer not grafted to the polymerized polyester, but the graft polymer in the present invention includes all of them.

(Polymerization Initiator and Other Additives) As the graft polymerization initiator that can be used in the present invention, organic peroxides and organic azo compounds known to those skilled in the art can be used. As an organic peroxide, benzoyl peroxide, t-butyl peroxypivalate, as an organic azo compound,
Examples thereof include 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylpareronitrile). The amount of the polymerization initiator used for performing the graft polymerization is at least 0.1 with respect to the polymerizable monomer.
It is at least 2% by weight, preferably at least 0.5% by weight. 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, or the like can be used as necessary. In this case, it is desirable to add in the range of 0 to 5% by weight based on the polymerizable monomer.

(Reaction solvent) The grafting reaction solvent for carrying out the present invention is preferably composed of an aqueous organic solvent having a boiling point of 50 to 250 ° C. Here, the aqueous organic solvent has a solubility in water at 20 ° C. of at least 10 g /
L or more, desirably 20 g / L or more.
Those having a boiling point exceeding 250 ° C. are unsuitable because the evaporation rate is too slow to remove sufficiently even by baking the coating film at a high temperature. When the boiling point is 50 ° C. or less,
When the grafting reaction is carried out using it as a solvent, 50
The use of an initiator that decomposes into radicals at a temperature of not more than ° C. increases the danger in handling, which is not preferred. Examples of the first group of aqueous organic solvents that dissolve the copolymerized polyester resin well and relatively well dissolve the polymerizable monomer mixture containing the carboxyl group-containing polymerizable monomer and the polymer include 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 -Ter, ethylene glycol ethyl ether, ethylene glycol butyl ether, carbitols such as methyl carbitol, ethyl carbitol, butyl carbitol, glycols or lower esters of glycol ether Such as ethylene glycol diacete
And ethylene glycol ethyl ether acetate, ketone alcohols such as diacetone alcohol, and N-substituted amides such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like.

On the other hand, as a second group of aqueous organic solvents, which hardly dissolve the copolymerized polyester resin but contain the carboxyl group-containing polymerizable monomer, and relatively well dissolve the polymer. , Water, lower alcohols, lower carboxylic acids, lower amines, etc., and particularly preferable for the practice of the present invention are alcohols and glycols having 1 to 4 carbon atoms.

When the grafting reaction is carried out with 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 both cases where the graft polymerization reaction solvent is a single solvent from the first group of aqueous organic solvents, and when it is a mixed solvent comprising one kind of each of the first and second groups of aqueous organic solvents. A graft polymerization reaction can be performed. However, there are differences in the progress of the grafting reaction, the appearance and properties of the grafting reaction product and the aqueous dispersion derived therefrom, and a mixed solvent composed of one of the first and second groups of aqueous organic solvents, respectively. It is preferable to use

In the first group of solvents, the copolyester molecular chains are in a state of extended chains, while in the mixed solvent of the first group / second group, they are in a state of entanglement in a small-spread thread. This was confirmed by measuring the viscosity of the copolymerized polyester in these solutions. It is effective to prevent gelation by adjusting the dissolution state of the copolymerized polyester so as to prevent intermolecular crosslinking. Both high efficiency of grafting 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 more preferably from 95/5 to 10/90, further preferably 90/10.
-20/80, most preferably 85 / 15-30 / 70
Range. The optimum mixing ratio is determined according to the solubility of the polyester used.

(Water dispersion) The grafting reaction product according to the present invention is preferably neutralized with a basic compound.
By neutralizing, it can be easily dispersed in water. As the basic compound, a compound which volatilizes at the time of forming a coating film or at the time of baking and curing by adding a curing agent is desirable, and ammonia, organic amines and the like are preferable. Examples of desirable compounds include triethylamine, N, N-diethylethanolamine, N, N-dimethylethanolamine, aminoethanolamine, N-methyl-N, N-diethanolamine,
Isopropylamine, iminobispropylamine, ethylamine, diethylamine, 3-ethoxypropylamine, 3-diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, dimethylaminopropylamine, methyliminobispropylamine, 3-methoxy Examples thereof include propylamine, monoethanolamine, diethanolamine, and triethanolamine. The basic compound has a pH value of the aqueous dispersion in the range of 5.0 to 9.0 by at least partial neutralization or complete neutralization depending on the carboxyl group content contained in the grafting reaction product. Preferably, it is used as follows. If 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 of a metal or an inorganic vapor-deposited film or the water resistance when laminated with other materials. Excellent hot water adhesion. Also one
When a basic compound having a temperature of 00 ° C. or higher is used or drying conditions are controlled, and the basic compound is left in a coating film after drying of 500 ppm or more, transferability of the printing ink is improved.

In the aqueous dispersion produced according to the present invention,
The weight average molecular weight of the polymer of the radical polymerizable monomer is 500-
Preferably it is 50000. It is generally difficult to control the weight-average molecular weight of the polymer of the radical polymerizable monomer to 500 or less, and the grafting efficiency tends to decrease, and there is a tendency that the hydrophilic group is not sufficiently provided to the copolymerized polyester. is there. Further, the graft polymer of the radical polymerizable monomer forms a hydrated layer of the dispersed particles, but in order to provide a hydrated layer having a sufficient thickness and obtain a stable dispersion, The weight average molecular weight of the graft polymer is desirably 500 or more. Further, the upper limit of the weight average molecular weight of the graft polymer of the radical polymerizable monomer is preferably 50,000 from the viewpoint of polymerizability in solution polymerization. The control of the molecular weight within this range can be carried out by appropriately combining an initiator amount, a monomer dropping time, a polymerization time, a reaction solvent, a monomer composition or, if necessary, a chain transfer agent and a polymerization inhibitor.

In the present invention, a reaction product obtained by graft-polymerizing a radically polymerizable monomer onto a hydrophobic copolymerized polyester resin has a self-crosslinking property. Does not crosslink at room temperature,
With the heat during drying, 1) dehydration of silanol groups present in the reaction product, 2) intermolecular reaction such as hydrogen abstraction reaction by thermal radicals, and crosslinking without a crosslinking agent. Thereby, the adhesiveness and water resistance, which are the objects 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 determined by the insoluble fraction in a chloroform solvent that dissolves both the hydrophobic copolymerized polyester resin and the radical polymer. Dry at 80 ° C or less, 5 at 120 ° C
The insoluble content of the coating film obtained by the heat treatment for 50 minutes is preferably 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 which can be used in the present invention as it is, but can be further cured by adding a crosslinking agent (curing resin) to the adhesion-modified layer. It can impart a high degree of water resistance.

Examples of the crosslinking agent include a phenol formaldehyde resin of a condensate of alkylated phenols and cresols with formaldehyde; an adduct of urea, melamine, benzoguanamine and the like with formaldehyde, and the adduct having 1 to 1 carbon atom. An amino resin such as an alkyl ether compound composed of alcohol No. 6; a polyfunctional epoxy compound; a polyfunctional isocyanate compound; a blocked isocyanate compound; a polyfunctional aziridine compound; an oxazoline compound.

Examples of the phenol formaldehyde resin include, for example, alkylated (methyl, ethyl, propyl,
Isopropyl or butyl) phenol, p-tert
-Amylphenol, 4,4'-sec-butylidenephenol, p-tert-butylphenol, o-, m
-, P-cresol, p-cyclohexylphenol,
4,4′-isopropylidenephenol, p-nonylphenol, p-octylphenol, 3-pentadecylphenol, phenol, phenyl o-cresol, p
-Condensates of phenols such as 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 methoxylated methylolmelamine, butoxylated methylolmelamine, and methylolated benzoguanamine.

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 isocyanurate ,
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.

As the polyfunctional isocyanate compound,
Low-molecular or high-molecular aromatic or aliphatic diisocyanates and trivalent or higher polyisocyanates can be used. 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, an excess amount of these isocyanate compounds and a low-molecular active hydrogen compound such as ethylene glycol, propylene glycol, trimethylolpropane, glycerin, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, or polyester polyols, Examples thereof include a terminal isocyanate group-containing compound obtained by reacting a polymer active hydrogen compound such as ether polyols and polyamides.

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, methyl etiketoxime, and cyclohexanone oxime. Alcohols such as methanol, ethanol, propanol and butanol; halogen-substituted alcohols such as ethylene chlorohydrin and 1,3-dichloro-2-propanol; t-butanol and t-
Tertiary alcohols such as pentanol; ε-caprolactam, δ-valerolactam, ν-butyrolactam, β
Lactams such as propyl lactam; aromatic amines; imides; active methylene compounds such as acetylacetone, acetoacetate ester, and malonic acid ethyl ester; mercaptans; imines; ureas; diaryl compounds; Can be mentioned.

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 from 5 parts by weight to 4 parts by weight based on 100 parts by weight of the grafted copolymer.
0 parts by weight is preferred. As a method of compounding the crosslinking agent,
(1) When the crosslinking agent is water-soluble, a method of dissolving or dispersing it directly in an aqueous solvent solution or dispersion of the graft copolymer, or (2) When the crosslinking agent is oil-soluble, after completion of the grafting reaction And a method of adding to a reaction solution. 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 which can be used in the present invention as it is, but for other purposes, a general-purpose polyester resin, urethane resin, acrylic resin, a copolymer thereof, Various water-soluble resins, etc., and various functional resins, for example, a conductive resin such as polyaniline or polypyrrole, an antibacterial resin, an ultraviolet absorbing resin, and a gas barrier resin may be mixed to form an adhesion reforming layer. Absent.

Additives such as various surfactants, antistatic agents, inorganic lubricants, organic lubricants, antibacterial agents, photooxidation catalysts, ultraviolet absorbers, etc. are added to the adhesion modifying layer as long as the effects of the present invention are not impaired. Can be contained.

As the polyamide film used in the present invention, for example, nylon 6 using ε-caprolactam as a main raw material can be mentioned. As other polyamide resins, a polyamide resin obtained by polycondensation of a lactam having three or more rings, an ω-amino acid, a dibasic acid and a diamine can be considered. Specifically, in addition to ε-caprolactam shown above as lactams, enantholactam, caprylactam, lauryl lactam, and ω-amino acids are 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid , 11-aminoundecanoic acid and dibasic acids include adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandionic acid, dodecadionic acid, hexadecadionic acid eicosandioic acid and eicosadiene On-acid, 2,
2,4-trimethyladipic acid, terephthalic acid isophthalic acid, 2,6-naphthalenedicarboxylic acid, xylylenedicarboxylic acid, and as diamines, ethylenediamine, trimethylenediamine, tetramethylenediamine,
Hexamethylenediamine pentamethylenediamine, undecamethylenediamine, 2,2,4 (or 2,4
4) -trimethylhexamethylenediamine, cyclohexanediamine, bis- (4,4'-aminocyclohexyl) methane, meta-xylylenediamine, and the like,
Polymers obtained by polycondensing these or copolymers thereof, for example, nylon 6, 7, 11, 12, 6.6,
6.9, 6.11, 6.12, 6T, 6I, MXD6,
6 / 6.6, 6/12, 6 / 6T, 6 / 6I, 6 / MX
D6 and the like.

The polyamide film may contain various additives as long as the desired performance is not impaired. For example, antioxidants, light stabilizers, anti-gelling agents, organic lubricants and inorganic or organic particles as lubricants, anti-blocking agents, pigments,
An olefin, amide, styrene, or polyester resin, or a thermoplastic elastomer thereof, or EVOH, MXD6 to blend an antistatic agent, a surfactant, etc., and to improve impact resistance and moisture absorption properties. A resin having a gas barrier property such as polyethylene naphthalate or the like may be blended or laminated.

The polyamide film of the present invention can be formed by a known film forming method. As a film forming method, a T-die method, an inflation method, or the like is applied. Further, the polyamide film of the present invention may be a single layer or a multilayer film such as coextrusion.

(Laminated Polyamide Film) In the laminated polyamide film of the present invention, the adhesion modifying layer present on at least one surface of the polyamide film substrate is obtained by applying a coating liquid containing the above graft copolymer onto the polyamide film substrate. By doing so, it can be suitably formed.

As the coating liquid, an organic solvent solution or dispersion of the graft copolymer constituting the adhesion modifying layer, or an aqueous solvent solution or aqueous solvent dispersion can be used. In particular, an aqueous solution or dispersion is preferable in that an organic solvent which is problematic for the environment is not used. The solid content of the graft copolymer in an organic solvent or an aqueous solvent is usually 1
% To 50% by weight, preferably 3% to 30% by weight
It is.

There are no particular restrictions on the drying conditions of the graft copolymer after coating. However, in order to exhibit the self-crosslinking property of the graft copolymer, thermal degradation of the base film and the graft copolymer is required. As long as it does not occur, a condition for increasing the amount of heat is preferable. Specifically, the temperature is from 80C to 250C, more preferably from 150C to 220C. 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.

The adhesion-modifying layer may further contain additives such as an antistatic agent, an inorganic lubricant, an organic lubricant, an antibacterial agent, and a photooxidation catalyst, as long as the effects of the present invention are not impaired.
These are contained in a coating agent and applied to the substrate surface.

As a method for applying a coating solution containing a graft copolymer to a polyester film substrate to form an adhesion modified layer, there are known methods such as a gravure method, a reverse method, a die method, a bar method, and a dip method. Can be used.

The coating amount of the coating solution is 0.00
5 to 10 g / m ² , preferably 0.02 to 0.5 g / m ²
m ² . If the coating amount is less than 0.005 g / m ² , sufficient adhesive strength with the adhesion modifying layer cannot be obtained. 10
When it is more than g / m ² , blocking occurs, and there is a practical problem.

The adhesion-modified layer may be formed by applying the above-mentioned coating solution to a biaxially stretched polyamide film substrate, or by applying the above-mentioned coating solution to a non-stretched or uniaxially stretched polyamide film substrate and then drying. If necessary, heat setting may be performed after uniaxial stretching or biaxial stretching.

When applied on a biaxially stretched polyamide film, the polyamide film is subjected to a surface treatment such as a corona treatment, a flame treatment, or an electron beam irradiation in order to further improve the adhesion between the polyamide film and the adhesion modifying layer. Is also good. Even when the film is stretched after the following application, the same effect can be obtained.

When the above coating solution is applied to a non-stretched or uniaxially stretched polyamide film substrate and then dried and stretched, it is necessary to dry under a condition that the drying temperature after the application does not affect the subsequent stretching. Yes, for polyamide base,
The film is stretched by setting the moisture content to 2% or less and then heat-set at 200 ° C. or more, whereby the coating film becomes strong, and the adhesiveness between the adhesion-modified layer and the polyester film substrate is remarkably improved. When the water content is 2% or more, it depends on the drying temperature,
In some cases, crystallization occurs and the crystallization becomes cheaper, and the flatness is deteriorated and the stretchability is impaired.

The adhesion-modified layer of the laminated polyamide film of the present invention has good adhesion to various materials, but in order to further improve the adhesion and printability, the adhesion-modified layer is further subjected to corona treatment and flame treatment. Alternatively, a surface treatment such as electron beam irradiation may be performed.

The adhesion-modified layer of the laminated film obtained in the present invention can provide good adhesive strength in a wide range of applications. Specifically, printing inks, UV inks, adhesives such as dry laminations and extrusion laminations, vacuum evaporation of metals or inorganic substances or oxides thereof, electron beam evaporation, sputtering, ion plating, CVD, plasma polymerization, etc. And the like, a thin film layer, an oxygen absorbent layer, an organic barrier layer, and an inkjet image receiving layer.

[0049]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. In the examples, “parts” means “parts by weight”, and “%” means “% by weight”. Each measurement item followed the following method.

1) Evaluation of Adhesiveness (Preparation of Laminate) Thickness 15 obtained in each Example and Comparative Example
The printing ink layer is formed by gravure printing a gravure ink (Lamiace 61 white two-liquid type, manufactured by Toyo Ink Co., Ltd.) on the adhesion modified layer of the laminated polyamide film having a thickness of μm, and then a two-liquid curing type AC agent (EL530A and EL530B) (Manufactured by Toyo Morton Co., Ltd.), followed by LDPE extrusion lamination according to a conventional method to provide a sealant layer, thereby obtaining a polyamide film laminate. Normal storage (dry and wet) and 90
The peel strength in hot water at ℃ was measured. The measurement conditions are the results of a 90 ° peel test at a tensile speed of 100 mm / min. 2) Glass transition temperature (Tg) The solution or dispersion is applied to a glass plate,
To obtain a graft copolymer solid content. 10 mg of this solid content was placed in a sample pan, and 1
Tg was measured by scanning at a rate of 0 ° C./min.

(Preparation of copolymerized polyester) Dimethyl terephthalate 3 was placed in a stainless steel autoclave equipped with a stirrer, a thermometer, and a partial reflux condenser.
45 parts, 211 parts of 1,4 butanediol, 270 parts of ethylene glycol, and 0.5 part of tetra-n-butyl titanate were charged, and a transesterification reaction was performed from 160 ° C. to 220 ° C. for 4 hours. Then, fumaric acid 1
Add 4 parts and 160 parts of sebacic acid, and
The temperature was raised to 20 ° C. over 1 hour to carry out an esterification reaction. Next, the temperature was raised to 255 ° C., and the pressure in the reaction system was gradually reduced. Then, the reaction was carried out under a reduced pressure of 0.22 mmHg for 1 hour and 30 minutes to obtain a polyester (A-1). The obtained polyester was pale yellow and transparent. In a similar manner, a polyester resin (A-2) having another copolymer composition was obtained. (A-
Table 1 shows the composition and weight average molecular weight of 1) and (A-2) measured by NMR.

[Table 1]

Example 1 A reactor equipped with a stirrer, a thermometer, a reflux device and a metered-dropping device was charged with 75 parts of the copolymerized polyester resin (A-1), 56 parts of methyl ethyl ketone, and 19 parts of isopropyl alcohol. The mixture was heated and stirred at ℃ to dissolve the resin. After the resin was completely dissolved, 15 parts of maleic anhydride was added to the polyester solution. Then, a solution of 10 parts of styrene and 1.5 parts of azobisdimethylvaleronitrile dissolved in 12 parts of methyl ethyl ketone was dropped into the polyester solution at 0.1 ml / min,
Stirring was continued for another 2 hours. After sampling for analysis from the reaction solution, 5 parts of methanol was added. Next, 300 parts of water and 15 parts of triethylamine were added to the reaction solution, followed by stirring for 1 hour. Then, the temperature inside the reactor was raised to 100 ° C.
Then, methyl ethyl ketone, isopropyl alcohol and excess triethylamine were distilled off by distillation to obtain a water-dispersed graft polymer resin B-1. The water-dispersed graft resin (B-1) is pale yellow and transparent, and has a glass transition temperature of -10 ° C.
Met. The water-dispersed graft resin (B-1) was mixed with water: isopropyl alcohol =
The coating solution was prepared by diluting at a ratio of 9: 1 (weight ratio). The nylon 6 resin is melt-extruded at 280 ° C. and cooled with a cooling roll at 15 ° C. to obtain an unstretched film having a thickness of 185 μm.
This unstretched film was stretched 3.5 times in the longitudinal direction between a pair of rolls at 85 ° C. having different peripheral speeds. Next, the above coating solution was applied by a die coater method, and dried with hot air at 70 ° C.
Next, the film was stretched 3.5 times in the transverse direction at a tenter temperature of 100 ° C., and heat-set at 200 to 220 ° C. to obtain a biaxially stretched coated polyamide film having a thickness of 15 μm. The final coating agent application amount was 0.1 g / m ² .

Example 2 A water-dispersed graft resin (B-2) was obtained in the same manner as in Example 1 except that maleic anhydride was changed to 8 parts and styrene was changed to 17 parts. The water-dispersed graft resin (B-2) is pale yellow and transparent, and has a glass transition temperature of -10 ° C.
Met. The water-dispersed graft resin (B-2) was used in Example 1.
A coated polyester film was obtained in the same manner as described above.

(Example 3) In a reactor equipped with a stirrer, a thermometer, a reflux device and a fixed-rate dropping device, 75 parts of the copolymerized polyester resin (A-1), 56 parts of methyl ethyl ketone, and 19 parts of isopropyl alcohol were charged. The mixture was heated and stirred at ℃ to dissolve the resin. After the resin was completely dissolved, 15 parts of maleic anhydride was added to the polyester solution. Next, a solution prepared by dissolving 10 parts of styrene and 1.5 parts of azobisdimethylvaleronitrile in 12 parts of methyl ethyl ketone was dropped into the polyester solution at 0.1 ml / min. After dropping, stirring was further continued for 2 hours to obtain a solvent-type graft polymerization resin (B-3). The glass transition temperature of the obtained solvent-type graft polymerization resin was -10 ° C. This solvent-type resin (B-3) was diluted with methyl ethyl ketone to a solid content concentration of 5% to prepare a primer coating solution.
Next, it was applied on a 100-μm-thick biaxially stretched polyester film manufactured by Toyobo Co., Ltd. with a roll coater, and then dried at 150 ° C. to obtain a coated polyester film. The final coating agent application amount was 0.2 g / m ² . Table 2 shows the evaluation results of the obtained films.

[Table 2]

Example 4 Copolymerized polyester resin (A
A water-dispersed graft resin (B-4) was obtained in the same manner as in Example 1, except that (A-2) was used instead of (-1). The water-dispersed graft resin (B-4) is pale yellow and transparent, and has a glass transition temperature of -1.
5 ° C. A coating polyamide film was obtained from the water-dispersed graft resin (B-2) in the same manner as in Example 1. Table 2 shows the evaluation results of the obtained coated polyamide films.

(Comparative Example 1) In a reactor equipped with a stirrer, a thermometer, a reflux device and a metered-dropping device, 75 parts of the copolymerized polyester resin (A-1), 56 parts of methyl ethyl ketone and 19 parts of isopropyl alcohol were added. The mixture was heated and stirred at ℃ to dissolve the resin. After the resin was completely dissolved, a solution of a mixture of 17.5 parts of methacrylic acid and 7.5 parts of ethyl acrylate and a solution of 1.2 parts of azobisdimethylvaleronitrile in 25 parts of methyl ethyl ketone was 0.2 ml / m2.
The solution was dropped into the polyester solution at "in", and stirring was further continued for 2 hours. After sampling for analysis from the reaction solution, 300 parts of water and 25 parts of triethylamine were added to the reaction solution and stirred for 1 hour. Then, the temperature inside the reactor was raised to 100 ° C.
Then, methyl ethyl ketone, isopropyl alcohol and excess triethylamine were distilled off by distillation to obtain a water-dispersed graft resin (B-5). The obtained resin (B-
5) was pale yellow and transparent, and had a glass transition temperature of -20 ° C. A coating polyamide film was prepared from the above water-dispersed graft resin in the same manner as in Example 1. Table 2 shows the evaluation results of the obtained coated polyamide films.

(Comparative Example 2) The water-dispersed graft resin (B-5) obtained in Comparative Example 1 was diluted with water: isopropyl alcohol = 9: 1 (weight ratio) so as to have a solid concentration of 5%, and applied. The liquid was adjusted. Next, it was coated on a 15-μm-thick biaxially stretched polyamide film used in Example 3 with a roll coater, and then dried at 120 ° C. to obtain a coated polyamide film. The final coating agent application amount was 0.1 g / m ² . Table 2 shows the evaluation results of the obtained films.

Comparative Example 3 As a dicarboxylic acid component, 46 mol% of dimethyl terephthalate, 47 mol% of dimethyl isophthalate and sodium 5-sulfoisophthalate 7
Mol%, ethylene glycol 50 mol% and neopentyl glycol 50 mol% as glycol components.
Was used to carry out a transesterification reaction and a polycondensation reaction in a conventional manner. The glass transition temperature of the obtained sulfonic acid group-containing polyester was 69 ° C. 300 parts of the sulfonic acid group-containing polyester and 150 parts of n-butyl cellosolve were heated and stirred to form a viscous solution, and 550 parts of water was gradually added with further stirring to obtain a solid content of 30% by weight.
Was obtained as a homogeneous pale white aqueous dispersion. This dispersion was further added to a mixture of equal amounts of water and isopropanol to prepare an aqueous dispersion of a sulfonic acid group-containing polyester having a solid content of 5% by weight. Next, the same thickness of 15 μm as used in Example 3.
On a biaxially stretched polyamide film, and then dried at 120 ° C. to obtain a coated polyamide film. The final coating agent application amount is 0.1 g /
m ² . Table 2 shows the evaluation results of the obtained films.

[0059]

According to the present invention, a laminated polyamide film having excellent adhesion and water resistance can be obtained by providing a predetermined polyester-based graft copolymer on a polyamide film.

Continuation of the front page (51) Int.Cl. ⁶ Identification code FI // B65D 65/40 B65D 65/40 D B29K 77:00 105: 24 B29L 9:00 (72) Inventor Shusei Matsuda Ozu Kizu, Inuyama City, Aichi Prefecture 344 Maebata, Toyobo Co., Ltd.Inuyama Plant (72) Inventor Ishi Nakatani Inuyama City, Aichi Prefecture Oji Kizu 344 Maebata, Toyo Boseki Co., Ltd.Inuyama Plant (72) Inventor Takashi Igawa Ozu Kizu, Inuyama City, Aichi Prefecture 344, Maebata, Toyobo Co., Ltd., Inuyama Plant

Claims (4)

[Claims] 1. A self-crosslinkable polyester-based graft copolymer comprising a hydrophobic polyester-based resin and at least one polymerizable unsaturated monomer grafted on at least one surface of a polyamide film substrate. A laminated polyamide film having a layer, wherein the polymerizable unsaturated monomer contains at least one monomer containing an acid anhydride having a double bond. 2. A layer containing the self-crosslinkable polyester-based graft copolymer as a component, and a coating liquid containing the self-crosslinkable polyester-based graft copolymer is applied to an unstretched or uniaxially stretched film, and dried. The laminated polyamide film according to claim 1, wherein the film is further formed by stretching the film uniaxially or more and heat setting the film. 3. The laminated polyamide film according to claim 1, wherein the polyester-based graft copolymer has a glass transition temperature of 30 ° C. or lower. 4. The laminated polyamide film according to claim 1, wherein the polymerizable unsaturated monomer contains at least maleic anhydride and styrene.