JPH0994936A - Polyamide film laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyamide film laminate characterized by that the respective layers constituting the laminate, especially, a polyamide film and a sealant layer are good in adhesiveness and hold high adhesiveness at a time of a wet state and at a time of heat treatment. SOLUTION: A polyamide film laminate is obtained by successively laminating an adhesive modifying layer, a printing ink layer, an adhesive layer and a sealant layer on at least the single surface of a polyamide film being a base material and the adhesive modifying layer contains a graft polymer consisting of polyester and an acrylic polymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide film laminate, and more particularly, it is suitable for packaging bags for water-containing foods and chemicals, or for severe treatments such as boiling water treatment and retort treatment. It relates to a polyamide film laminate.

[0002]

2. Description of the Related Art Biaxially stretched polyamide films are excellent in toughness, pinhole resistance, bending resistance and heat resistance, and are widely used for various purposes. When such a polyamide film is used as a packaging bag, generally, at least one surface is optionally printed, an adhesive is provided thereon, and a sealant layer is further provided thereon by a dry lamination method. Alternatively, a laminate of polyamide films is manufactured by providing a sealant layer by an extrusion laminating method. Then, a bag is formed using this laminated body, the contents are filled, and the opening is heat-sealed. Such packaging bags are used, for example, for packaging seasonings such as miso and soy sauce, water-containing foods such as soups and retort foods, or chemicals.

[0003]

However, when moisture penetrates into each layer constituting the biaxially stretched polyamide film laminate, the adhesive force between the layers is significantly reduced, which causes bag breakage when used as a packaging bag. . For example, when the retort food is subjected to boiling water treatment or retort treatment, the bag is more easily broken. In addition, multi-color printing on the entire surface has become widespread as packaging products become more sophisticated, and the problem of a decrease in the adhesive force between layers due to the presence of a printing ink layer also arises. Further, when the adhesive layer is interposed between the biaxially stretched polyamide film layer and the sealant layer, depending on the type of the adhesive, depending on the humidity,
The adhesive strength of some adhesives is easily affected, and the adhesive strength of moisture-curable adhesives is particularly noticeable, and the adhesive strength greatly varies depending on the season. The present invention is intended to solve the above points, and an object thereof is a polyamide film laminate having good adhesion between a polyamide film and a sealant layer, and having high adhesion even during wet and heat treatments. To provide.

[0004]

The present invention is a polyamide film laminate in which an adhesion modifying layer / printing ink layer / adhesive layer / sealant layer are sequentially laminated on at least one side of a polyamide film as a substrate. The adhesion modifying layer contains a graft polymer composed of polyester and an acrylic polymer, which is a polyamide film laminate.

Next, the present invention will be described in detail. The polyamide film laminate of the present invention has an adhesion modifying layer / printing ink layer / printing ink layer / printing ink layer on at least one surface of a polyamide film as a substrate.
The adhesive layer / sealant layer is sequentially laminated. The polyamide film is a film containing a polyamide resin as a main component, and examples of the polyamide resin include a polyamide resin by polycondensation of lactams having three or more membered rings, a polyamide resin by polycondensation of ω-amino acid, a dibasic acid and a diamine. Polyamide resin obtained by polycondensation with Specific examples of lactams having three or more membered rings include ε-caprolactam, enanthlactam, capryllactam, and lauryllactam. As the ω-amino acid,
6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid and the like can be mentioned. As the dibasic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecadioic acid, hexadecadioic acid, eicosandioic acid, eicosadiendioic acid,
2,2,4-trimethyladipic acid, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, xylylenedicarboxylic acid and the like can be mentioned. Diamines include ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine pentamethylenediamine, undecamethylenediamine, 2,2,4.
(Or 2,4,4) -trimethylhexamethylenediamine, cyclohexanediamine, bis- (4,4'-aminocyclohexyl) methane, metaxylylenediamine and the like. Examples of polymers obtained by polycondensation of these or copolymers thereof include nylon 6, nylon 7, nylon 11, nylon 12, nylon 6.
6, nylon 6.9, nylon 6.11, nylon 6.
12, nylon 6T, nylon 6I, nylon MXD
6, nylon 6 / 6.6, nylon 6/12, nylon 6 / 6T, nylon 6 / 6I, nylon 6 / MXD6 and the like.

The above polyamide film contains various additives such as an antioxidant, a light stabilizer, an antigelling agent, a lubricant, an antiblocking agent, a pigment, an antistatic agent, and a surfactant unless the intended performance is impaired. Is also good.

The polyamide film can be formed by a known film forming method, for example, the T-die method,
The inflation method is adopted. The polyamide film may be a single layer film or a multilayer film such as coextrusion.

The adhesion modifying layer is formed on a polyamide film and contains a graft polymer composed of polyester and an acrylic polymer. In this graft polymer, the trunk polymer may be polyester and the branch polymer may be an acrylic polymer, or the trunk polymer may be an acrylic polymer and the branch polymer may be polyester. The graft polymer may be soluble or dispersible in an organic solvent, or may be soluble or dispersible in an aqueous solvent. It is particularly preferable to use a so-called aqueous graft polymer that can be dissolved or dispersed in an aqueous solvent due to environmental problems.

Polyester is a substantially linear polymer synthesized from a polybasic acid or its ester-forming derivative and a polyol or its ester-forming derivative. As the polybasic acid component of this polymer, aromatic dicarboxylic acids, aliphatic dicarboxylic acids, alicyclic dicarboxylic acids and dicarboxylic acids having a polymerizable unsaturated double bond can be used. Specific examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid and the like, and 5-sodium sulfoisophthalic acid can also be used if necessary. Examples of the aliphatic dicarboxylic acid include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, dimer acid, and the like, and as the alicyclic dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1, Examples thereof include 3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid and acid anhydrides thereof. The dicarboxylic acid having a polymerizable unsaturated double bond, fumaric acid, maleic acid, maleic anhydride, itaconic acid, α, β-unsaturated dicarboxylic acids such as citraconic acid; 2,5-norbornane dicarboxylic acid anhydride, Examples thereof include alicyclic dicarboxylic acid having an unsaturated double bond such as tetrahydrophthalic anhydride. Most preferred among them are fumaric acid, maleic acid and 2,5-norbornene dicarboxylic acid (endo-bicyclo- (2,2,1) -5-heptene-2,3-dicarboxylic acid). By using a dicarboxylic acid having a polymerizable unsaturated double bond as a copolymerization component, a polyester having a polymerizable unsaturated double bond in the main chain is obtained,
It can be graft-polymerized with an acrylic monomer.

The dicarboxylic acid component having a polymerizable unsaturated double bond is preferably 0.5 to 10 mol%, more preferably 2 to 7 mol%, particularly preferably 3 to 6 based on the total acid component. Mol%. When the content of the dicarboxylic acid component having a polymerizable unsaturated double bond is less than 0.5 mol%, it is difficult to efficiently graft the radically polymerizable monomer onto the polyester, resulting in a dispersed particle size in an aqueous medium. Tends to increase, and dispersion stability tends to decrease. On the other hand, when the dicarboxylic acid having a polymerizable unsaturated double bond exceeds 10 mol%, the viscosity is too high in the latter stage of the grafting reaction and the uniform progress of the reaction is hindered, which is not preferable.

On the other hand, the glycol component has 2 to 10 carbon atoms.
The above-mentioned aliphatic glycol and / or alicyclic glycol having 6 to 12 carbon atoms and / or glycol having an ether bond, and examples of the aliphatic glycol having 2 to 10 carbon atoms include ethylene glycol and 1,2-propylene. Glycol, 1,3-propanediol, 1,4-butanediol, 1,5-petanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-
1,5-pentanediol, 1,9-nonanediol,
2-Ethyl-2-butylpropanediol and the like can be mentioned, and as the alicyclic glycol having 6 to 12 carbon atoms, 1,4-cyclohexanedimethanol and the like can be mentioned. As the glycol having an ether bond, diethylene glycol, triethylene glycol,
Dipropylene glycol, and bisphenols 2
Glycols obtained by adding one to several moles of ethylene oxide or propylene oxide to one phenolic hydroxyl group, for example, 2,2-bis- (4-hydroxyethoxyphenyl) propane can be mentioned. Polyethylene glycol, polypropylene glycol and polytetramethylene glycol can also be used if necessary.

The above polyester may contain a trifunctional or higher functional polycarboxylic acid and / or polyol as a copolymerization component. Trifunctional or higher polycarboxylic acid (anhydrous)
Examples thereof include trimellitic acid, (anhydrous) pyromellitic acid, (anhydrous) benzophenone tetracarboxylic acid, trimesic acid, ethylene glycol bis (anhydrotrimellitate), and glycerol tris (anhydrotrimellitate). Glycerin as a trifunctional or higher functional polyol,
Trimethylolethane, trimethylolpropane, pentaerythritol and the like can be mentioned. The trifunctional or higher polycarboxylic acid and / or polyol is preferably 0 to 5 mol%, more preferably 0 to 3 with respect to the total acid component or the total glycol component constituting the polyester.
Copolymerization is preferable in the range of mol%. By using such a copolymerization component, a polyester having a carboxyl group and / or a hydroxyl group in a side chain is obtained, and the polyester can be graft-polymerized with an acrylic polymer having a functional group capable of reacting with these groups.

As the acrylic polymer monomer, alkyl acrylate or alkyl methacrylate (as the alkyl group, methyl group, ethyl group, n-propyl group, isopropyl group, t-butyl group, 2-ethylhexyl group,
Cyclohexyl group, phenyl group, benzyl group, phenylethyl group, etc.); 2-hydroxyethyl acrylate, 2
-Hydroxy-containing monomers such as hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate; acrylamide,
Methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N, N-dimethylolacrylamide, N-methoxymethylacrylamide, N-methoxymethylmethacrylamide, N-phenylacrylamide Amide group-containing monomers such as N; N
-Amino group-containing monomers such as diethylaminoethyl acrylate and N, N-diethylaminoethyl methacrylate; Epoxy group-containing monomers such as glycidyl acrylate and glycidyl methacrylate; Acrylic acid, methacrylic acid and salts thereof (sodium salt, potassium salt, ammonium salt) And a monomer containing a carboxyl group or a salt thereof. These can be used in combination with the following monomers, if necessary. For example, an epoxy group-containing monomer such as allyl glycidyl ether; a monomer containing a sulfonic acid group such as styrenesulfonic acid, vinylsulfonic acid, or a salt thereof (sodium salt, potassium salt, ammonium salt, etc.) or a salt thereof; crotonic acid, Itaconic acid, maleic acid, fumaric acid or salts thereof (sodium salt, potassium salt, ammonium salt, etc.)
Monomers containing carboxyl groups or salts thereof such as;
Monomers containing acid anhydrides such as maleic anhydride and itaconic anhydride; vinyl isocyanate, allyl isocyanate, styrene, vinyl methyl ether, vinyl trialkoxysilane, alkyl maleic acid monoester, alkyl fumaric acid monoester, acrylonitrile, methacryloyl Nitrile, alkyl itaconic acid monoester,
Examples thereof include vinylidene chloride, vinyl acetate, vinyl chloride and the like. The above monomers may be used alone or in combination of two or more to be copolymerized with the acrylic monomer.

The method for producing the graft polymer is exemplified by the following methods, but is not limited thereto. (1) A method of generating a reaction initiation point of radicals, cations or anions in polyester and graft-polymerizing an acrylic monomer. For example, a radical polymerization method in which a radical is generated in polyester by light, heat or radiation and then an acrylic monomer is graft-polymerized,
A cationic polymerization method in which a cationic group is generated in polyester using a catalyst such as lCl ₃ or TiCl ₄ and then an acrylic monomer is graft-polymerized, an anionic group is generated in polyester using metallic sodium or metallic lithium, and then acrylic is used. Anionic polymerization or the like in which a system monomer is graft-polymerized may be used. (2) A method of introducing a polymerizable unsaturated bond into the main chain, terminal chain or side chain of polyester and graft-polymerizing an acrylic monomer. As a method of introducing a polymerizable unsaturated bond into the main chain, a method of copolymerizing a dicarboxylic acid containing a polymerizable unsaturated bond such as fumaric acid or maleic acid during the production of polyester, a polymerizable unsaturated at the terminal As a method of introducing a bond, a method of reacting a monomer having a polymerizable unsaturated bond that reacts with a hydroxyl group such as acrylic acid at a hydroxy terminal of polyester, a method of introducing a polymerizable unsaturated bond into a side chain As the polyester having a carboxyl group or a hydroxyl group in the side chain, glycidyl acrylate, 2-hydroxyethyl acrylate,
Examples thereof include a method of reacting a monomer having a polymerizable unsaturated bond and having reactivity with a carboxyl group or a hydroxyl group such as acrylic acid. (3) A method of directly reacting a polyester having a functional group in a side chain with an acrylic polymer having a group that reacts with the functional group at the end, or an acrylic polymer having a functional group in the side chain and at the end A method of directly reacting a polyester having a functional group and a reactive group. (4) A method in which a polyester having a functional group on the side chain and an acrylic polymer having a functional group at the terminal are bonded with a bifunctional coupling agent reactive with the functional group, or a functional group on the side chain A method in which an acrylic polymer having ## STR3 ## and a polyester having a functional group at the end are bound with a bifunctional coupling agent having reactivity with the functional group. The weight ratio of the trunk polymer to the branch polymer in the graft polymer is preferably 5:95 to 95: 5, more preferably 10:90 to 90:10. When the weight ratio of the trunk polymer is less than 5 or more than 95, the water-resistant adhesiveness of the obtained film decreases, which is not preferable. The molecular weight of the trunk polymer is preferably 5,000 to 200,000, and the molecular weight of the branch polymer is preferably 500 to 50,000. The graft polymer is
Although it is used as it is, a high degree of water resistance can be exhibited by adding a crosslinking agent (curing resin) and curing the mixture. Examples of the cross-linking agent include phenol formaldehyde resin, amino resin, polyfunctional epoxy compound, polyfunctional isocyanate compound and various blocked isocyanate compounds thereof, polyfunctional aziridine compound, and oxazoline compound.

Examples of phenol formaldehyde resins include formaldehyde condensates of alkylated phenols and cresols. Specifically, alkylated (methyl, ethyl, propyl, isopropyl, butyl) phenol, p-tert-amylphenol, 4,4′-sec-butylidenephenol, p-
tert-butylphenol, o-, m-, p-cresol, p-cyclohexylphenol, 4,4'-isopropylidenephenol, p-nonylphenol, p-
Examples thereof include formaldehyde condensates such as octylphenol, 3-pentadecylphenol, phenol, phenyl o-cresol, p-phenylphenol, and xylenol.

Examples of amino resins include formaldehyde adducts such as urea, melamine and benzoguanamine,
Further, an alkyl ether compound containing an alcohol having 1 to 6 carbon atoms can be mentioned. Specific examples 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. , Preferably methoxylated methylolmelamine, butoxylated methylolmelamine, and methylolated benzoguanamine, which can be used alone or in combination.

Examples of the polyfunctional epoxy compound include diglycidyl ether of bisphenol A and its oligomer, diglycidyl ether of hydrogenated bisphenol A and its oligomer, orthophthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, and terephthalic acid diglycidyl ester. , P-oxybenzoic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, succinic acid diglycidyl ester, adipic acid diglycidyl ester, sebacic acid diglycidyl ester,
Ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether and polyalkylene glycol diglycidyl ethers, trimellitic acid triglycidyl ester, triglycidyl isocyanate Nurate, 1,4
-Diglycidyloxybenzene, diglycidyl propylene urea, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol triglycidyl ether, triglycidyl ether of glycerol alkylene oxide adduct and the like can be mentioned.

Examples of polyfunctional isocyanate compounds include aromatic diisocyanates, aliphatic diisocyanates, and trivalent or higher polyisocyanates, which may be low molecular compounds or high molecular compounds. For example, tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate or a trimer of these isocyanate compounds, and excess of these isocyanate compounds. The amount of the low molecular weight active hydrogen compound such as ethylene glycol, propylene glycol, trimethylolpropane, glycerin, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine or various polyester polyols, polyether polyols, polyamides Reacts with high molecular weight active hydrogen compounds Allowed include terminal isocyanate group-containing compounds obtained.

The isocyanate compound may be a blocked isocyanate compound. Examples of the isocyanate blocking agent include phenols such as phenol, thiophenol, methylthiophenol, cresol, xylenol, resorcinol, nitrophenol, and chlorophenol; oximes such as acetoxime, methylethylketoxime, and cyclohexanone oxime; methanol, ethanol, propanol, Alcohols such as butanol; ethylene chlorohydrin,
Halogen-substituted alcohols such as 1,3-dichloro-2-propanol; tertiary alcohols such as t-butanol and t-pentanol; ε-caprolactam, δ-valerolactam, γ-butyrolactam, β-propyllactam and the like. And other aromatic amines; imides; active methylene compounds such as acetylacetone, acetoacetic acid ester, malonic acid ethyl ester; mercaptans; imines; ureas; diaryl compounds; sodium bisulfite And so on. The blocked isocyanate compound is obtained by subjecting the above-mentioned isocyanate compound and an isocyanate blocking agent to an addition reaction by a conventionally known appropriate method.

Further, the adhesion modifying layer may contain additives such as an antistatic agent, an inorganic lubricant and an organic lubricant within a range that does not impair the effects of the present invention.

As a coating method for forming the adhesion modifying layer, a usual coating method such as a gravure method, a reverse method, a die method, a bar method and a dip method can be adopted.

The graft polymer is preferably applied as an aqueous dispersion, and the average particle size of the dispersion at that time is preferably 500 nm or less, more preferably 10 nm.
~ 300 nm.

The polyamide film to be applied may be applied to a biaxially stretched polyamide film, or may be applied to an unstretched or uniaxially stretched polyamide film and dried,
If necessary, the coated polyamide film may be obtained by further uniaxially or biaxially stretching and then heat setting. The drying temperature after coating is preferably 150 ° C. or higher, and by heat-setting at 200 ° C. or higher, the coating film becomes stronger and the adhesion between the adhesion modifying layer and the polyamide film is improved.
Further, when stretching is performed after coating, it is preferable to control the water content of the polyamide film after coating to be in the range of 0.1 to 2% so that drying after coating does not impair the stretchability. Also in this case, after stretching, by heat setting at 200 ° C. or higher,
The coating film becomes strong, and the adhesiveness between the coating agent and the polyamide film is dramatically improved.

The coating amount is 0.01 to 1 g / m as solid content.
² , preferably 0.02 to 0.5 g / m ² . If the coating amount is less than 0.01 g / m ² , sufficient adhesive strength cannot be obtained, and if it exceeds 1 g / m ² , blocking occurs, which is a practical problem.

The printing ink layer is formed on the adhesion modifying layer. As a component constituting the printing ink layer, an ink having a cellulose derivative as a binder or a gravure ink having a synthetic resin as a binder is mainly used, and particularly when the obtained polyamide film laminate is required to have boiling water resistance, An ink containing vinyl chloride, polyester, polyether, polyol or the like having a functional group such as a hydroxyl group at the terminal as a binder is used after adding a curing agent.
The method for forming on the adhesion-modified layer is formed by printing, wholly or partially, or as an arbitrary pattern by printing.

The adhesive layer is formed on the printing ink layer.
The adhesive constituting the adhesive layer is preferably an isocyanate-based adhesive when the sealant layer provided on the adhesive layer is provided by extrusion laminating, for example, a reaction between diisocyanate and polyhydric alcohol as a one-pack type. Examples thereof include polyurethane having an NCO group at the terminal, or prepolymer having an NCO group at the terminal. As the two-pack type, polyisocyanate and a polyol or a polyurethane prepolymer having an OH group at the terminal are mixed before use. When the sealant layer is laminated by dry lamination, vinyl-based resin, acrylic-based resin, polyamide-based resin, epoxy-based resin, urethane-based resin and the like can be mentioned, but mainly polyisocyanate and polyol are mixed just before use. The polyurethane adhesive used is preferred. The adhesive layer is formed by applying a solution or emulsion of these resins according to a conventional method.

A sealant layer is formed on the adhesive layer.
Sealant layer is LDPE (low density polyethylene), E
A synthetic resin such as VA (ethylene-vinyl acetate copolymer), ionomer or PP (polypropylene) is extruded on the adhesive layer of the polyamide film or laminated by dry lamination.

[0028]

The function of the adhesion-modifying layer contains a graft polymer composed of polyester and an acrylic polymer. The functional group (eg, carboxyl group) of the acrylic polymer in this graft polymer reacts with the isocyanate used in the adhesive layer to form a network, so that the adhesive layer has excellent water resistance. Adhesion between the polyamide film and the sealant material becomes good. Further, since the polyester in the graft polymer has a good affinity with the polyamide film, the adhesion between the polyamide film and the adhesion-modified layer becomes good, and therefore the adhesion between the polyamide film and the sealant material becomes even better. . Furthermore, the adhesion-modified layer also has the mechanical strength and heat resistance inherent in polyester.

[0029]

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) Weight average molecular weight 0.03 g of resin is dissolved in 10 cc of tetrahydrofuran, and GPC-LALLS apparatus low angle light scattering photometer LS-
It measured with 8000 (Tosoh Corporation, tetrahydrofuran solvent, reference: polystyrene).

(2) Weight average molecular weight measurement of graft side chain The product obtained by graft polymerization was subjected to hydrolysis of the copolyester under reflux in a KOH / water-methanol solution. The decomposition product was extracted with THF under acidic conditions, and the radical polymerizable polymer was purified by reprecipitation with hexane. This polymer was measured with a GPC device (manufactured by Shimadzu Corporation, tetrahydrofuran solvent, converted to polystyrene), and the weight average molecular weight of the graft side chain was calculated.

(3) Aqueous dispersion particle size The aqueous dispersion is prepared by using only ion-exchanged water to obtain a solid concentration of 0.1.
Laser light scattering particle size distribution meter Coulter m adjusted to wt%
It was measured at 20 ° C. with odel N4 (manufactured by Coulter).

(4) Aqueous dispersion B type viscosity The viscosity of the aqueous dispersion is a rotational viscometer (manufactured by Tokyo Keiki Co., Ltd., EM).
Type) and was measured at 25 ° C.

(5) Glass Transition Point (Tg) The aqueous dispersion was applied on a glass plate and dried at 170 ° C. to obtain the polyester resin solid content. 10 mg of this polyester
Was placed in a sample pan and scanned with a differential scanning calorimeter at a rate of 10 ° C./min to measure Tg.

(6) Peel strength (normal state) The peel strength of the obtained polyamide film laminate during normal storage (dry and wet) was measured by a tensile tester at a pulling speed of 100 mm / min at a 90 ° peel test. It was measured.

(7) Method for measuring peel strength in hot water The peel strength of the obtained polyamide film laminate in hot water at 90 ° C. was measured by a tensile tester at a pulling speed of 100 mm /
It was measured by a 90 ° peel test at min.

Example 1 In a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux condenser, 466 parts of dimethyl terephthalate, 466 parts of dimethyl isophthalate, 401 parts of neopentyl glycol and 44 parts of ethylene glycol.
3 parts and 0.52 part of tetra-n-butyl titanate were charged, and transesterification reaction was carried out from 160 ° C. to 220 ° C. for 4 hours. Then add 23 parts of fumaric acid and add 2
The temperature was raised from 00 ° C to 220 ° C over 1 hour to carry out an esterification reaction. Then, the temperature was raised to 255 ° C., the pressure of the reaction system was gradually reduced, and then the pressure was reduced to 0.2 mmHg for 3 hours for 1 hour.
After reacting for 0 minutes and stirring, polyester was obtained. The obtained polyester was pale yellow and transparent, had a glass transition temperature of 60 ° C, and a weight average molecular weight of 12,000. The composition measured by NMR and the like was as follows. Dicarboxylic acid component terephthalic acid 48 mol% isophthalic acid 48 mol% fumaric acid 4 mol% diol component neopentyl glycol 50 mol% ethylene glycol 50 mol% A reactor equipped with a stirrer, a thermometer, a reflux device and a metering dropping device is used as described above. 75 parts of polyester resin, 56 parts of methyl ethyl ketone, and 19 parts of isopropyl alcohol were added and heated at 65 ° C. and stirred to dissolve the resin. After the resin was completely dissolved, 25 parts of a mixture of 17.5 parts of methacrylic acid and 7.5 parts of ethyl acrylate and 1.2 parts of azobisdimethylvaleronitrile were added.
0.2 ml of a solution dissolved in 1 part of methyl ethyl ketone
/ Min into the polyester solution and stirring was continued for 2 hours. Sampling for analysis from reaction solution (5
g), 300 parts of water and 25 parts of triethylamine were added to the reaction solution, and the mixture was stirred for 1 hour. Then, the temperature of the dispersion was raised to 100 ° C., and methyl ethyl ketone, isopropyl alcohol, and excess triethylamine were distilled off by distillation. The resulting graft polymer aqueous dispersion was white and had an average particle size of 300 nm and a B-type viscosity at 25 ° C. of 50.
It was cps. When the molecular weight of the radical-polymerizable polymer was measured by GPC by hydrolyzing the copolymerized polyester portion of the solid content, the weight average molecular weight was 10,000. This aqueous dispersion was diluted with water to a solid content concentration of 5%, applied to a biaxially stretched polyamide film having a thickness of 15 μm by a gravure method, and then dried at 150 ° C. to form a polyamide film having an adhesion-modified layer. Got The coating amount after drying of the aqueous dispersion of the obtained film was 0.2 g / m ² . A gravure ink (Lamiace 61 white two-liquid type, manufactured by Toyo Ink Co., Ltd.) is gravure-printed on the coated surface of the polyamide film on which the adhesion modifying layer is formed to form a printing ink layer, and then a one-liquid moisture curing type. AC agent (T-10
4, manufactured by Nippon Soda Co., Ltd.) to form an adhesive layer.
Then, LDPE (low-density polyethylene) extrusion lamination was performed on the adhesive layer according to a conventional method to form a sealant layer to obtain a polyamide film laminate. This laminate was stored under normal conditions (dry and wet) and the peel strength in hot water at 90 ° C. was measured. Measurement conditions are tensile strength 100m
It is a 90 degree peeling test result in m / min. Table 1 shows the evaluation results.
Shown in

Example 2 An aqueous dispersion of the graft polymer of Example 1 was added to give a solid content of 10
The coating liquid was prepared by diluting with water so that the concentration became%. A polyamide resin screw type extruder is used to heat and melt at 260 ° C, extrude from a T die, and cool the unstretched sheet to 50 by a cooling drum.
The coating solution was applied to a polyamide film that had been longitudinally stretched 3.2 times at ℃ by the gravure method so that the coating amount was 4 g / m ^2, and the water content of the coated polyamide film was 1%. After being dried so as to have a width of 4 times, the film was transversely stretched at 120 ° C. by 4 times, and then heat-set at 220 ° C. to obtain a polyamide film having an adhesion-modified layer with a thickness of 15 μm. The coating amount of the water dispersion after drying was 0.2 g / m ² . Then, a printing ink layer, an adhesive layer, and a sealant layer were formed in the same manner as in Example 1 to obtain a polyamide film laminate. The peel test results are shown in Table 1.

Example 3 A polyester having the following composition was obtained by the same method as in Example 1 except that the copolymerization component was changed from that in Example 1. The glass transition temperature was -10 ° C. Dicarboxylic acid component terephthalic acid 56 mol% sebacic acid 40 mol% fumaric acid 4 mol% diol component neopentyl glycol 50 mol% ethylene glycol 50 mol% This polyester was water-dispersed in the same manner as in Example 1, and the resulting graft weight was obtained. The combined aqueous dispersion was white and had an average particle size of 200 nm and a B-type viscosity at 25 ° C. of 90 cps.
Met. Further, using this dispersion, an adhesion modifying layer, a printing ink layer, an adhesive layer and a sealant layer were formed on a polyamide film in the same manner as in Example 1 to obtain a polyamide film laminate. The peel test results are shown in Table 1.

Example 4 Using the aqueous dispersion of the graft polymer of Example 3, a polyamide film laminate was obtained in the same manner as in Example 2. The peel test results are shown in Table 1.

Example 5 A polyester having the following composition was obtained by the same method as in Example 1 except that the copolymerization component was changed from that in Example 1. The glass transition temperature was 30 ° C. Dicarboxylic acid component terephthalic acid 48 mol% isophthalic acid 39 mol% sebacic acid 9 mol% fumaric acid 4 mol% diol component neopentyl glycol 50 mol% ethylene glycol 50 mol% This polyester was dispersed in water in the same manner as in Example 1. The resulting graft polymer aqueous dispersion was white and had an average particle size of 150 nm and a B-type viscosity at 25 ° C. of 100 cp.
It was s. Further, using this dispersion, an adhesion modifying layer, a printing ink layer, an adhesive layer and a sealant layer were formed on a polyamide film in the same manner as in Example 2 to obtain a polyamide film laminate. The peel test results are shown in Table 1.

Comparative Example 1 A polyester having the following composition was obtained in the same manner as in Example 1. Terephthalic acid 35 mol% isophthalic acid 35 mol% fumaric acid 30 mol% diol component neopentyl glycol 50 mol% ethylene glycol 50 mol% The above polyester was dissolved in methyl ethyl ketone to a solid content concentration of 5%, and the same as in Example 1. An adhesion modifying layer was formed on the polyamide film, and then a printing ink layer, an adhesive layer and a sealant layer were formed to obtain a polyamide film laminate. The peel test results are shown in Table 1.

Comparative Example 2 Thickness 1 with surface tension of 53 dynes / cm by corona treatment
A gravure ink (Lamiace 61 white two-liquid type, manufactured by Toyo Ink Co., Ltd.) is gravure-printed on the corona-treated surface of a 5 μm biaxially stretched film to form a printing ink layer, and then a one-liquid moisture effect type AC agent (T- 104, made by Nippon Soda Co., Ltd.)
Was applied to form an adhesive layer. Then on the adhesive layer,
LDPE (low density polyethylene) extrusion lamination was performed according to a conventional method to form a sealant layer to obtain a polyamide film laminate. This laminate was stored under normal conditions (dry and wet) and the peel strength in hot water at 90 ° C. was measured. The measurement conditions are the 90 ° peel test results at a tensile strength of 100 mm / min. Table 1 shows the evaluation results.

[0043]

[Table 1]

From Table 1, it can be seen that the polyamide film laminates produced from the polyamide films having the adhesion-modified layers of Examples 1 to 5 have high peel strength in dry, wet and hot water. .

[0045]

EFFECTS OF THE INVENTION As is clear from the above description, the polyamide film laminate of the present invention has good adhesiveness, and particularly has excellent hot water adhesiveness with a sealant material laminated by dry lamination or extrusion lamination. Excel. Since the laminate having the laminated polyamide film sealant layer laminated thereon is excellent in water resistance and durability, the bag breakage is extremely small even if it is subjected to retort treatment or boiling water treatment, and therefore it is widely used as a packaging bag for moisture-containing foods.

Claims (1)

[Claims] 1. A polyamide film laminate in which an adhesion modifying layer / printing ink layer / adhesive layer / sealant layer are sequentially laminated on at least one surface of a polyamide film as a substrate, wherein the adhesion modifying layer comprises: A polyamide film laminate comprising a graft polymer composed of polyester and an acrylic polymer.