JPH09174777A - Laminated polyamide film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To have a sufficient oxygen barrier property, a water-vapor barrier property, and retort resistance by laminating an organic substance layer containing a graft copolymer of polyester and acrylic polymer and an inorganic oxide layer in sequence on one side of a polyamide film base material. SOLUTION: A laminated polyamide film in which an organic substance layer containing a graft copolymer of polyester and acrylic polymer and an inorganic oxide layer are laminated in sequence at least on one side of a polyamide film base material The glass transition temperature of the graft copolymer is 30 deg.C or lower preferably 10 deg.C or lower. As a method for preparing the graft copolymer, a method in which a starting point for radical, cationic, or anionic polymerization is generated on a polyester molecule, and a monomer including at least an acrylic monomer is graft-polymerized from the point etc., are used.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a gas barrier material, a retort resistance, a gelling property which is excellent as a packaging material or a gas barrier material which is required to be airtight for foods, pharmaceuticals, electronic parts and the like. It's about the film you have.

[0002]

2. Description of the Related Art As a film having excellent gas barrier properties, there are known a film obtained by laminating aluminum on a plastic film and a film obtained by coding vinylidene chloride or an ethylene-vinyl alcohol copolymer. In addition, as a film using an inorganic thin film, a film in which silicon oxide and aluminum oxide thin film layers are laminated is known.

[0003]

The conventional gas barrier film as described above has the following problems. The aluminum laminate is economical and has excellent gas barrier properties, but since it is opaque, the contents at the time of packaging cannot be seen, and those coated with vinylidene chloride or ethylene-vinyl alcohol copolymer are water vapor, The gas barrier property against oxygen and the like is not sufficient, and its performance is remarkably deteriorated especially at high temperature treatment. Further, regarding vinylidene chloride, chlorine gas is generated during incineration, and there is a concern that it may affect the global environment.

On the other hand, as a gas barrier film whose contents can be seen and which can be used in a microwave oven, Japanese Patent Publication No. 51-485.
No. 11, Si _x O _y (for example Si
A gas barrier film obtained by vapor deposition of O ₂ ) has been proposed, but a SiO _x system (x = 1.3 to
The sample No. 1.8) has a slightly brown color and is insufficient as a transparent gas barrier film.

Some aluminum oxides are mainly used (Japanese Patent Application Laid-Open No. 62-101428), but the oxygen barrier property is insufficient and there is a problem of bending resistance. Further, as an example of an Al ₂ O ₃ .SiO ₂ system as a gas barrier film having a retort property, Japanese Patent Application Laid-Open No.
Al ₂ O, although some have been proposed in 194944
_It is a stack of ₃ and SiO ₂ , and its production requires large-scale equipment. In addition, the gas barrier properties and flex resistance of these thin film gas barrier films are still insufficient. In other words, to have retort resistance, it must be above a certain level (for example, 200 nm).
The thin film is required to be thin, but it has the problem that it is better to be as thin as possible to improve the flex resistance, and those currently used for retorts should be handled with care. I have. As described above, at present, there is no transparent gas barrier film having both oxygen barrier property and water vapor barrier property, retort resistance and high flexibility.

[0006] Polyamide-based films are widely used as packaging materials because of their excellent strength, but they easily permeate water vapor and their gas barrier properties deteriorate due to moisture absorption. Attempts have been made to improve the gas barrier properties by laminating the above-mentioned inorganic oxides using a polyamide film as a substrate, but the present situation is that high gas barrier properties have not been realized. further,
When this film is exposed to high humidity, the inorganic oxide layer deteriorates because the film absorbs moisture and its dimensions are elongated. Therefore, the gas barrier performance is significantly deteriorated.

[0007]

The present invention is intended to provide a gas barrier film in which a polyamide film having excellent strength is provided with excellent gas barrier performance. That is, the present invention is a laminated polyamide film in which an organic material layer containing a graft copolymer of polyester and an acrylic polymer and an inorganic oxide layer are sequentially laminated on at least one surface of a polyamide film substrate.

In a preferred embodiment of the present invention, the glass transition point of the above graft copolymer is 30 ° C. or lower.

In a preferred embodiment of the present invention, the organic layer is formed by applying a coating solution containing the graft copolymer to an unstretched polyamide film, and then biaxially stretching the coating film and heat-fixing it. It

In a preferred embodiment of the present invention, the organic layer is formed by applying a coating solution containing the graft copolymer to a uniaxially stretched polyamide film, and then further uniaxially stretching and heat setting the coated film. It

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION "Grafting" as used herein
The term "introduces a branch polymer made of a polymer different from the main chain into the main chain of the trunk polymer".

In the present specification, "acrylic monomer"
Means an acrylic acid derivative or a methacrylic acid derivative.

In the present specification, "acrylic polymer"
The term "polymer" refers to a polymer obtained from a polymerizable monomer containing at least an acrylic acid derivative or a methacrylic acid derivative. In the present specification, the "aqueous solvent" refers to a solvent which is mainly composed of water and which optionally contains a hydrophilic organic solvent.

(Graft Copolymer) In the graft copolymer that can be used in the present invention, 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 weight ratio of the trunk polymer to the branch polymer in the graft copolymer is 5:95 to 95: 5, preferably 80:20 to 20:80.

The molecular weight of the trunk polymer is 5,000 to 200,000, preferably 50 when the trunk polymer is polyester.
It is from 00 to 50,000. When the trunk polymer is an acrylic polymer, it is 5000 to 200,000, preferably 500.
It is 0 to 100,000.

The molecular weight of the branch polymer is 500 to 50,000, preferably 500 when the branch polymer is polyester.
It is 0 to 30,000. When the branch polymer is an acrylic polymer, it is 500 to 50000, preferably 4000 to 5
0000.

The glass transition temperature of the graft copolymer is 3
The temperature is 0 ° C or less, preferably 10 ° C or less.

If the physical properties of the graft copolymer deviate from the above range, the effect of the organic layer containing the graft copolymer will not be exhibited.

By including such a graft copolymer in the organic layer, the gas barrier performance of the inorganic oxide layer formed thereon can be stabilized.

(Preparation of Graft Copolymer) As a method for preparing the above graft copolymer, the following methods can be used, but the method is not limited thereto.

(1) A reaction initiation point of radical, cation or anionic polymerization is generated on the polyester molecule,
A method of graft-polymerizing a monomer containing at least an acrylic monomer using this.

According to this method, a graft copolymer in which the polyester is the trunk polymer and the acrylic polymer is the branch polymer is obtained.

Graft copolymerization generates radicals on polyester molecules by light, heat or radiation,
Next, radical polymerization method in which a monomer containing at least an acrylic monomer is graft-polymerized; a cation is generated on a polyester molecule by using a catalyst such as AlCl ₃ or TiCl ₄ , and then a cationic polymerization is carried out in which a monomer containing at least an acrylic monomer is graft-polymerized. Or an anionic polymerization method in which an anion is generated on a polyester molecule by using metallic sodium or metallic lithium, and then a monomer containing at least an acrylic monomer is graft-copolymerized.

(2) A polyester having a polymerizable unsaturated bond in the main chain, main chain terminal or side chain is prepared in advance,
A method of graft-polymerizing a monomer containing at least an acrylic monomer to this.

According to this method, a graft copolymer in which the polyester is a trunk polymer and the acrylic polymer is a branch polymer is obtained.

As a method for preparing a polyester having a radically polymerizable unsaturated bond in the main chain, a method of copolymerizing a dicarboxylic acid having a polymerizable unsaturated bond at the time of producing the polyester can be used.

As a method for preparing a polyester having a polymerizable unsaturated bond at the main chain terminal, a hydroxyl group such as a carboxyl group, an acid anhydride group, an acid chloride, an epoxy group or an isocyanate group is prepared at the hydroxy terminal of the polyester. A method of reacting a polymerizable monomer having a reactive group and a polymerizable unsaturated bond can be used. Alternatively, a method may be used in which a carboxyl group of polyester is reacted with a polymerizable monomer having a polymerizable unsaturated bond and a functional group capable of reacting with a carboxyl group such as a hydroxyl group, an amino group, or an isocyanate group.

As a method for preparing a polyester having a polymerizable unsaturated bond in the side chain, a carboxyl group or a hydroxyl group present in the polyester side chain portion is combined with a functional group reactive with these groups and a polymerizable group. A method of reacting a polymerizable monomer having a saturated bond can be used.

(3) A polyester having a functional group in the side chain and an acrylic polymer having a group reactive with this functional group at the polymer chain end, or an acrylic polymer having a functional group in the side chain and this functional group A method of directly reacting a polyester having a reactive group at the polymer chain end.

According to the former method, a graft copolymer in which the polyester is the trunk polymer and the acrylic polymer is the branch polymer is obtained. The latter method gives a graft copolymer in which the acrylic polymer is the backbone polymer and the polyester is the branch polymer.

As the functional group of the polyester side chain, a hydroxyl group, a carboxyl group or the like can be used. Examples of the group capable of reacting with the functional group of the polyester side chain present at the chain end of the acrylic polymer include a group capable of reacting with a hydroxyl group, for example, a carboxyl group, an acid anhydride group, an acid chloride group, an epoxy group, and an isocyanate. Examples of the group and the group capable of reacting with the carboxyl group include an amino group and an isocyanate group.
Acrylic polymers having such functional groups at the polymer chain ends are known in the art as macromers and can be prepared using known methods.

As the functional group of the side chain of the acrylic polymer, a hydroxyl group, a carboxyl group, an acid chloride group,
Acid anhydride groups, epoxy groups, amino groups, isocyanate groups, and the like can be used.

As the polyester chain terminal group capable of reacting with the functional group of the acrylic polymer side chain, a hydroxyl group and a carboxyl group can be used.

(4) A polyester having a functional group at the side chain and an acrylic polymer having a functional group at the terminal or an acrylic polymer having a functional group at the side chain and a polyester having a functional group at the terminal are used as these functional groups. A method of binding with a bifunctional coupling agent having reactivity.

According to the former method, a graft copolymer in which the polyester is the trunk polymer and the acrylic polymer is the branch polymer is obtained. The latter method gives a graft copolymer in which the acrylic polymer is the backbone polymer and the polyester is the branch polymer.

As the functional groups of the polyester and the acrylic polymer, the functional groups described in (3) above can be used.

(Polyester) The polyester for preparing the above-mentioned graft copolymer is preferably a saturated or unsaturated polyester synthesized from at least a dicarboxylic acid component and a diol component. A desired polyester as a raw material is prepared and utilized according to the above. The polyester can be one polymer or a mixture of two or more polymers.

In the preparation methods (1) to (4) of the graft copolymer, when polyester is used as the trunk polymer, the dicarboxylic acid component is an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid or an alicyclic dicarboxylic acid. Can be used, and if necessary, for example, a dicarboxylic acid having a polymerizable unsaturated double bond can be copolymerized in the preparation method (2).

In all the dicarboxylic acid components, the aromatic dicarboxylic acid is 30 to 99.5 mol%, preferably 40 to 9.
99.5 mol%, the aliphatic and / or alicyclic dicarboxylic acid may be used in an amount of 0 to 70 mol%, preferably 0 to 60 mol%.

When a dicarboxylic acid having a polymerizable unsaturated double bond is copolymerized, a polymerizable unsaturated double bond is introduced into the polyester chain, and this can be used as a graft polymerization initiation point for the trunk polymer. The dicarboxylic acid having a polymerizable unsaturated double bond is 0.5% of the total polycarboxylic acid component.
-10 mol%, preferably 2 to 7 mol%, more preferably 3 to 6 mol% can be used. When it is less than 0.5 mol%, effective grafting of the polymerizable monomer that becomes the branch polymer to the polyester is difficult to be performed, so that when the graft copolymer is dispersed in the aqueous medium, the dispersed particle size tends to increase. Therefore, the dispersion stability tends to decrease.
When it exceeds 10 mol%, the viscosity of the reaction solution increases in the latter stage of the grafting reaction, and the reaction does not proceed uniformly.

As the aromatic dicarboxylic acid, terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid and the like can be used. Furthermore, sodium 5-sulfoisophthalate can also be used if necessary.

As the aliphatic dicarboxylic acid, succinic acid,
Adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, dimer acid, acid anhydrides thereof and the like can be used.

As the alicyclic dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, acid anhydrides thereof, and the like can be used.

Examples of the dicarboxylic acid having a polymerizable unsaturated double bond include α, β-unsaturated dicarboxylic acids such as fumaric acid, maleic acid, maleic anhydride, itaconic acid,
Citraconic acid, 2,5-norbornane dicarboxylic acid anhydride, tetrahydrophthalic anhydride, etc. can be used as the alicyclic dicarboxylic acid containing an unsaturated double bond. Among these, fumaric acid, maleic acid and 2,5-norbornene dicarboxylic acid (endo-bicyclo- (2,2,1)
-5-heptene-2,3-dicarboxylic acid) is preferred.

The diol component is an aliphatic glycol having 2 to 10 carbon atoms, an alicyclic glycol having 6 to 12 carbon atoms,
And at least one of ether bond-containing glycols.

As the aliphatic glycol having 2 to 10 carbon atoms, 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 and the like can be used.

As the alicyclic glycol having 6 to 12 carbon atoms, 1,4-cyclohexanedimethanol or the like can be used.

Examples of the ether bond-containing glycol include diethylene glycol, triethylene glycol, dipropylene glycol, and glycols obtained by adding one to several moles of ethylene oxide or propylene oxide to two phenolic hydroxyl groups of bisphenols, for example, 2,2-bis (4-hydroxyethoxyphenyl) propane or the like can be used. Polyethylene glycol, polypropylene glycol, and polytetramethylene glycol can also be used as needed.

In addition to the above dicarboxylic acid component and diol component, trifunctional or higher functional polycarboxylic acid and / or polyol may be copolymerized. In particular, when polyester is used as a trunk polymer in the preparation methods (2) to (4), the presence of a free hydroxyl group or carboxyl group in the polyester chain is caused by copolymerizing a polycarboxylic acid and / or polyol having a functionality of 3 or more. Since the probability becomes high, grafting of the trunk polymer can be efficiently performed.

Examples of the trifunctional or higher polycarboxylic acid include (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, (anhydrous) benzophenonetetracarboxylic acid, trimesic acid,
Ethylene glycol bis (anhydrotrimellitate), glycerol tris (anhydrotrimellitate) and the like can be used.

As the trifunctional or higher functional polyol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and the like can be used.

The trifunctional or higher polycarboxylic acid and / or polyol is 0 to 5 mol%, preferably 0 to 5 mol% based on the total polycarboxylic acid component containing the dicarboxylic acid component or the total polyol component containing the diol component. It can be used in the range of 3 mol%.

When the graft copolymer is made soluble or dispersible in an organic solvent, when a polyester is used as a trunk polymer as in the above preparation methods (1) to (4), a branch polymer is added as described later. The graft copolymer can be made soluble or dispersible in an organic solvent by copolymerizing a monomer having a long-chain alkyl group with an acrylic polymer. On the other hand, in the above preparation methods (3) and (4), when the polyester is used as the branch polymer, the graft copolymer can be made soluble or dispersible in an organic solvent.

When the graft copolymer is made to be soluble or dispersible in an aqueous solvent, when the polyester is used as the trunk polymer as in the above-mentioned preparation methods (1) to (4), it is a branch polymer as described later. By making a certain acrylic polymer hydrophilic, the graft copolymer can be made soluble or dispersible in an aqueous solvent. On the other hand, in the above preparation methods (3) and (4), when polyester is used as the branch polymer, a hydrophilic polymer such as polyethylene glycol is copolymerized, or a hydrophilic group such as a hydroxyl group, a carboxyl group or a metal sulfonate group is used. By making the polyester hydrophilic by adding a group, the graft copolymer can be made soluble or dispersible in an aqueous solvent.

(Acrylic Polymer) In the preparation methods (3) and (4) of the above graft copolymer, when an acrylic polymer is used as a trunk polymer, the acrylic polymer is a polyester polymer having a polyester chain terminal as a branch polymer. It may be a homopolymer or a copolymer of monomers including at least a monomer having a functional group, for example, a functional group capable of reacting with a hydroxyl group or a carboxyl group.

By using a monomer having a functional group at the end of the polyester chain, for example, a functional group capable of reacting with a hydroxyl group or a carboxyl group, a functional group capable of reacting with a hydroxyl group or a carboxyl group is introduced into the backbone polymer chain. Therefore, these groups can be used as grafting points for the trunk polymer.

Examples of the monomer having a functional group capable of reacting with the hydroxyl group at the end of the polyester chain include acrylic acid, methacrylic acid, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, acrylic acid chloride, methacrylic acid chloride, vinyl isocyanate, allyl isocyanate. , Methacryloyl isocyanate, vinyl trialkoxy silane and the like can be used.

Examples of the monomer having a functional group capable of reacting with the carboxyl group at the end of the polyester chain include acrylic acid and methacrylic acid derivatives having a hydroxyl group, such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and acrylates thereof. Can be used in place of methacrylate, vinyl isocyanate, allyl isocyanate, methacryloyl isocyanate and the like.

As the acrylic monomer, alkyl esters of acrylic acid and methacrylic acid such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate. , Benzyl acrylate, phenylethyl acrylate, lauryl acrylate, stearyl acrylate, and their acrylates replaced by methacrylates; acrylic acid and methacrylic acid derivatives having an amide group, for example, acrylamide, N-methylacrylamide, N-
Methylol acrylamide, N, N-dimethylol acrylamide, N-methoxymethyl acrylamide, N-
Phenyl acrylamide and methacrylamide substituted for these acrylamides; acrylic acid and methacrylic acid derivatives having amino groups, eg N, N
-Diethylaminoethyl acrylate and N, N-diethylaminoethyl methacrylate; These monomers may be used alone or in combination of two or more. Furthermore, if necessary, other monomers may be copolymerized.

Other monomers include nitriles such as acrylonitrile and methacrylonitrile; vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether. Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone; vinyl chloride, vinyl den chloride, Examples thereof include vinyl halides such as vinyl bromide and vinyl fluoride; aromatic vinyl compounds such as styrene, α-methylstyrene, t-butylstyrene, vinyltoluene and vinylnaphthalene; These monomers may be used alone or in combination of two or more.

In the preparation methods (1) to (4) for the graft copolymer, when an acrylic polymer is used as the branch polymer, the polyester as the trunk polymer is polymerizable in the molecule as in the preparation method (2). When it has an unsaturated double bond, a monomer containing at least the acrylic monomer can be directly graft-polymerized to form a branched polymer. On the other hand, when the polyester as the trunk polymer does not have a polymerizable unsaturated double bond in the molecule as in the above preparation methods (3) and (4), a functional group capable of reacting with a hydroxyl group or a carboxyl group is added to the polymer. A branched polymer can be formed by reacting an acrylic polymer having a chain end with a hydroxyl group or a carboxyl group in a polyester molecule which is a trunk polymer.

When the graft copolymer is made soluble or dispersible in an organic solvent, when the acrylic polymer is used as the trunk polymer as in the above preparation methods (3) and (4) of the graft copolymer, By making the polyester lipophilic, the graft copolymer can be made soluble or dispersible in organic solvents. On the other hand, when the acrylic polymer is used as a branch polymer as in the above preparation methods (1) to (4), an alkyl acrylate or alkyl having an alicyclic or long-chain alkyl such as 2-ethylhexyl, cyclohexyl, lauryl or stearyl. The graft copolymer may be rendered soluble or dispersible in organic solvents by copolymerizing the methacrylate.

When the graft copolymer is made soluble or dispersible in an aqueous solvent, when the acrylic polymer is used as the trunk polymer as in the above-mentioned graft copolymer preparation methods (3) and (4), By making the polyester hydrophilic as described above, the graft copolymer can be made soluble or dispersible in an aqueous solvent. On the other hand, when the acrylic polymer is used as a branch polymer as in the above preparation methods (1) to (4), it has a polymerizable group having a hydrophilic group or a group which can be changed to a hydrophilic group later. The graft copolymer is made soluble or dispersible in an aqueous solvent by copolymerizing the monomer in an amount of 5 to 95% by weight, preferably 10 to 90% by weight, more preferably 40 to 80% by weight based on the total weight of the monomer to form a branched polymer. You can

As the polymerizable monomer having a hydrophilic group or a group which can be converted into a hydrophilic group later, a monomer having a hydroxyl group, for example, 2-
Hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and those obtained by replacing these acrylates with methacrylates; monomers having a carboxyl group or a salt thereof, for example, acrylic acid, methacrylic acid,
Maleic acid, fumaric acid, itaconic acid, citraconic acid, alkyl maleic acid monoester, alkyl fumaric acid monoester, alkyl itaconic acid monoester, alkyl citraconic acid monoester, and salts thereof (sodium salt, potassium salt, ammonium salt, etc.) ); A monomer having a sulfonic acid group, for example, styrenesulfonic acid,
Vinyl sulfonic acids and their salts (sodium salt,
Potassium salt, ammonium salt, etc.); a monomer that is an acid anhydride, for example, maleic anhydride, itaconic anhydride; a monomer having a phosphoric acid group or a salt thereof, for example,
2- (methacryloyloxy) ethylphosphonic acid and its salts (sodium salt, potassium salt, ammonium salt, etc.); [2- (methacryloyloxy) ethyl] trimethylammonium chloride and other monomers having a quaternary ammonium group; obtain.

(Polymerization Initiator and Other Additives) As the graft polymerization initiator usable in the present invention, organic peroxides and organic azo compounds known to those skilled in the art can be used.

Benzoylperoxide, t-butylperoxypivalate as the organic peroxide, 2,2'-azobisisobutyronitrile as the organic azo compound,
2,2'-azobis (2,4-dimethylpareronitrile) and the like can be mentioned.

The amount of the polymerization initiator used for carrying out the graft polymerization is at least 0.2 with respect to the polymerizable monomer.
It is at least wt%, preferably at least 0.5 wt%.

In addition to the polymerization initiator, a chain transfer agent for controlling the chain length of the branch polymer, for example, octyl mercaptan, mercaptoethanol, 3-t-butyl-4-hydroxyanisole and the like can be used if necessary. In this case, it is desirable to add it in the range of 0 to 5% by weight with respect to the polymerizable monomer.

(Polyamide film base material) As the polyamide which can be used for the polyamide film base material in the present invention, for example, nylon 6, whose main raw material is ε-caprolactam, is a lactam having 3 or more membered rings, ω-amino acid, dibase. Polyamide obtained by polycondensation of acid and diamine may be used.

As lactams, in addition to ε-caprolactam, enantolactam, capryllactam, lauryllactam and the like can be used.

As ω-amino acids, 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 1
1-aminoundecanoic acid or the like can be used.

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 2,2,4-trimethyladipic acid, terephthalic acid isophthalic acid, 2,6-naphthalenedicarboxylic acid, xylylenedicarboxylic acid and the like can be used.

As the diamines, ethylenediamine,
Trimethylenediamine, tetramethylenediamine, hexamethylenediamine, pentamethylenediamine, undecamethylenediamine, 2,2,4 (or 2,4,4)
-Trimethylhexamethylenediamine, cyclohexanediamine, bis- (4,4'-aminocyclohexyl)
Methane, metaxylylenediamine and the like can be used.

Examples of the polymer or copolymer obtained by polycondensation of dibasic acid and diamine include nylon 6, 7, 11, 12, 6.6, 6.9, 6.11, and 6.
12, 6T, 6l, MXD6, 6 / 6.6, 6/12,
6 / 6T, 6 / 6l, 6 / MXD6 and the like.

The polyamide film substrate usable in the present invention may contain various additives as long as the intended performance is not impaired. Examples of the additive include an antioxidant, a light resistance agent, an antigelling agent, a lubricant, an antiblocking agent, a pigment, an antistatic agent, and a surfactant.

The polyamide film substrate that can be used in 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 can be used.

The polyamide film substrate that can be used in the present invention can be a single layer or a multilayer film formed by coextrusion or the like.

(Polyamide film having organic material layer)
In the laminated polyamide film of the present invention, the organic material layer present on at least one surface of the polyamide film substrate can be suitably formed by applying a coating solution containing the graft copolymer on the polyamide film substrate.

The coating liquid is an organic solvent solution or dispersion of the graft copolymer constituting the organic layer, or
Aqueous solvent solutions or aqueous solvent dispersions can be used. Especially,
Aqueous solutions or dispersions are preferable because they do not use an organic solvent that poses a problem to the environment. The average particle size of the graft copolymer particles, when dispersed in an organic solvent or an aqueous solvent, measured by a laser light scattering method is 500 nm or less, preferably 10 nm to 500 nm, more preferably 10 nm.
nm to 300 nm.

The solid content of the graft copolymer in the organic solvent or the aqueous solvent is usually 1% by weight to 50% by weight, preferably 3% by weight to 30% by weight.

When the graft copolymer is used by dispersing it in an aqueous solvent, the graft copolymer dispersed in the aqueous solvent is used.
¹³ C-NMR (measurement conditions: 125 MHz, 25 ° C., measurement solvent; heavy water, full width at half maximum of DSS signal is 5 Hz or less)
In the spectrum obtained by Fourier transform without applying a weighting function, the FWHM of the carbonyl carbon signal derived from the trunk polymer is 300 Hz or more, and the FWHM of the carbonyl carbon signal derived from the branch polymer is 150 Hz. The following is preferable.

In general, it is known that in ¹³ C-NMR, the chemical shift, full width at half maximum and relaxation time can be changed by reflecting the surrounding environment where the observed carbon atom is placed. For example, the signal of the carbonyl carbon of the polymer dissolved in heavy water is observed in the range of 170 to 200 ppm, and the full width at half maximum is about 300 Hz or less.
On the other hand, the signal of carbonyl carbon of the polymer which is insoluble in heavy water is observed in the range of 170 ppm to 200 ppm, and the half value width is about 300 Hz or more.

Since the trunk polymer and the branch polymer in the graft copolymer have the above-described full width at half maximum, the graft copolymer can have a core-shell structure having the trunk polymer as a core in an aqueous solvent. By having such a core-shell structure, the dispersion state of the polymer particles in the dispersion medium is stabilized. As a result, it is not necessary to use an emulsifier or an organic cosolvent that is often used in conventional dispersions, so that the water resistance of the organic material layer is improved.

The above-mentioned graft copolymer can form the organic material layer which can be used in the present invention as it is. However, by adding a crosslinking agent (curing resin) and curing it, the organic material layer is highly water resistant. Can be given.

As the cross-linking agent, a phenol-formaldehyde resin of a condensate of alkylated phenols, cresols and the like with formaldehyde; an adduct of urea, melamine, benzoguanamine and the like with formaldehyde, and the adduct and the number of carbon atoms are 1 to 1 An amino resin such as an alkyl ether compound composed of alcohol of 6; a polyfunctional epoxy compound; a polyfunctional isocyanate compound; a blocked isocyanate compound; a polyfunctional aziridine compound; an oxazoline compound and the like can be used.

Examples of the phenol-formaldehyde resin include 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
-Condensation products of formaldehyde with phenols such as phenylphenol and xylenol can be mentioned.

Examples of amino resins 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. The preferred examples include methoxylated methylol melamine, butoxylated methylol melamine, and methylolated benzoguanamine.

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 the like.
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, diglycidylpropylene urea, glycerol triglycidyl ether,
Examples thereof include trimethylolpropane triglycidyl ether, pentaerythritol triglycidyl ether, and triglycidyl ether of 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. There is. Furthermore, with an excess amount of these isocyanate compounds, low molecular weight active hydrogen compounds such as ethylene glycol, propylene glycol, trimethylolpropane, glycerin, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, or polyester polyols, poly Examples thereof include a terminal isocyanate group-containing compound obtained by reacting with a polymer active hydrogen compound such as ether polyols and polyamides.

The blocked isocyanate can be prepared by subjecting the above-mentioned 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, butanol; halogen-substituted alcohols such as ethylene chlorohydrin, 1,3-dichloro-2-propanol; t-butanol, t
-Tertiary alcohols such as pentanol; ε-caprolactam, δ-valerolactam, ν-butyrolactam,
Lactams such as β-propyllactam; aromatic amines; imides; active methylene compounds such as acetylacetone, acetoacetic ester, malonic acid ethyl ester; mercaptans; imines; ureas; diaryl compounds; sodium bisulfite etc. Can be mentioned.

These cross-linking agents may be used alone or in the form of 2
A mixture of more than one species can be used.

The content of the crosslinking agent is preferably 5 to 40 parts by weight with respect to 100 parts by weight of the graft copolymer.

As the method for blending the crosslinking agent, (1) when the crosslinking 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) the crosslinking agent is used. When it is oil-soluble, there is a method of adding it to the reaction solution after completion of the grafting reaction. These methods are
It 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.

Additives such as an antistatic agent, an inorganic lubricant and an organic lubricant can be added to the organic material layer within a range that does not impair the effects of the present invention. It is applied to the surface.

As a method of applying a coating solution containing a graft copolymer to a polyamide film base material to form an organic layer, known coating methods such as a gravure method, a reverse method, a die method, a bar method and a dip method are used. Can be used.

The coating amount of the coating liquid is 0.01 as the solid content.
˜1 g / m ² , preferably 0.02 to 0.5 g / m ² . If the coating amount is 0.01 g / m ² or less, sufficient adhesive strength between the organic layer and other layers cannot be obtained. 1 g / m ²
If it becomes the above, blocking will occur and it will be a problem in practice.

The organic layer is formed by applying the above coating solution to a biaxially stretched polyamide film base material, or applying the above coating solution to an unstretched or uniaxially stretched polyamide film base material and then drying it, if necessary. Further, it can be formed by further performing heat setting after uniaxial stretching or biaxial stretching. When a biaxially stretched polyamide film substrate is used, the coating film becomes strong by drying and heat-setting at a drying temperature of 150 ° C. or higher, preferably 200 ° C. or higher after coating with the coating liquid, and the organic layer is formed. Adhesion with a polyamide film substrate is improved.

When stretching is performed after coating, it is necessary to control the water content of the coated film in the range of 0.1 to 2% in drying after coating so as not to impair the stretchability of the coated film. After the stretching, by drying at 200 ° C. or higher and heat fixing, the coating film becomes strong, and the adhesiveness between the organic material layer and the polyamide film substrate is dramatically improved.

(Inorganic Oxide Layer) In the present specification, the term “inorganic oxide” refers to an oxide of a metal such as aluminum or magnesium or an oxide of a semi-metal such as silicon. It does not include carbon dioxide gas that is not solid at room temperature and pressure. The inorganic oxide of the present invention is a single atom oxide described above, or a mixture or complex of a plurality of inorganic oxides, for example, a complex oxide such as SiO ₂ —Al ₂ O ₃ or SiO ₂ —MgO. Can be. Further, oxides other than the complete oxide represented by SiO _x may be included. It may also contain impurities (such as carbon) by several%.

The thickness of the inorganic oxide layer is not particularly limited, but from the viewpoint of gas barrier property and flexibility, it is 5 to 500 n.
m is preferable, and more preferably 7 to 300 nm.

(Laminated Polyamide Film) The laminated polyamide film of the present invention is obtained by forming the above-mentioned inorganic oxide layer on the organic layer of a polyamide film having an organic layer. For forming the inorganic oxide layer, a vacuum vapor deposition method, a sputtering method, a PVD method (physical vapor deposition method) such as ion plating, or a CVD method (chemical vapor deposition method) can be appropriately used. When using the vacuum deposition method, the heating method is
Resistance heating, high frequency induction heating, electron beam heating and the like can be used. As the reaction gas, oxygen, nitrogen, water vapor or the like can be introduced, and reactive vapor deposition using means such as an ozone additive or ion assist can also be performed. Furthermore, the manufacturing conditions may be changed as long as the object of the present invention is not impaired by applying a bias or the like to the substrate, raising the substrate temperature, or cooling. In other manufacturing methods such as the sputter method and the CVD method, various manufacturing conditions can be changed according to the inorganic oxide layer.

[0103]

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 the polymer was dissolved in 10 ml of tetrahydrofuran, and the GPC-LALLS apparatus low angle light scattering photometer LS-8 was used.
000 (manufactured by Tosoh Corporation, tetrahydrofuran solvent, reference: polystyrene).

(2) Polyester Grafting Efficiency Using a UNITY 500 (manufactured by Varian), the product obtained by the graft polymerization was subjected to 1H-NMR of protons derived from the double bond of the double bond-containing component in the polyester. (2
20 MHz, measured measurement solvent _{CDC1 3 / DMSO-d 6)} , based on a change in intensity of the signal was calculated grafting efficiency using the following equation.

[0106]

[Equation 1]

The relative intensity was calculated by comparison with the signal intensity of the internal signal as a reference signal.

(3) Measurement of Weight Average Molecular Weight of Graft Side Chain The polyester was hydrolyzed by refluxing the graft copolymer in a KOH / water-methanol solution. The decomposition product was extracted with THF under acidic conditions, and the grafted portion was reprecipitated from the extract by reprecipitation with hexane for purification. The molecular weight of the obtained polymer was measured using a GPC apparatus (manufactured by Shimadzu Corporation, tetrahydrofuran solvent, converted to polystyrene), and the weight average molecular weight of the graft portion was calculated.

(4) Particle Size of Aqueous Dispersion An aqueous dispersion was prepared to a solid concentration of 0.1 wt% using only ion-exchanged water, and a laser light scattering particle size distribution analyzer Co
The particle size was measured at 20 ° C. using an ulter model N4 (manufactured by Coulter).

(5) Type B Viscosity of Solution or Dispersion The viscosity of the solution or dispersion was measured at 25 ° C. using a rotational viscometer (Tokyo Keiki Co., Ltd., EM type).

(6) Measurement of full width at half maximum of ¹³ C-NMR signal The aqueous dispersion was diluted with heavy water to a solid content concentration of 20% by weight, and then DSS was added thereto to prepare a measurement sample. . 2 using UNITY 500 (manufactured by Varian)
After setting the measurement conditions such that the DSS signal is 5 Hz or less at 5 ° C., ¹³ C-NMR (125
MHz) was measured and Fourier transform was performed without applying a weighting function. The full width at half maximum of the signal of the carbonyl carbon of the obtained trunk polymer and that of the signal of the carbonyl carbon of the branch polymer were measured.

(7) Glass transition point (Tg) The solution or dispersion is applied to a glass plate and then 170 ° C.
Then, the solid content of the graft copolymer was obtained by drying. 10 mg of this solid content was put into a sample pan, and 1 with a differential scanning calorimeter.
The Tg was measured by scanning at a rate of 0 ° C./min.

Example 1 (Preparation of Graft Copolymer) A stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux type condenser was placed in 540 parts of dimethyl terephthalate, 450 parts of neopentyl glycol and 405 parts of ethylene glycol. ,
Then, 0.52 parts of tetra-n-butyl titanate was charged, and the transesterification reaction was performed at 160 ° C to 220 ° C for 4 hours. Then, 30 parts of fumaric acid and 55 parts of sebacic acid were added, and the temperature was raised from 200 ° C to 220 ° C over 1 hour to carry out an esterification reaction. Then 255 ° C
Up to 0.2 mmH after gradually depressurizing the reaction system
The polyester was obtained by reacting with stirring under reduced pressure of 1 hour and 30 minutes. The obtained polyester is light yellow and transparent, has a glass transition temperature of -10 ° C and a weight average molecular weight of 120.
00. The composition obtained by NMR measurement and the like was as follows.

[0114]

[Table 1]

75 parts of the above polyester, 56 parts of methyl ethyl ketone and 19 parts of isopropyl alcohol were placed in a reactor equipped with a stirrer, a thermometer, a reflux device and a constant amount dropping device, and heated at 65 ° C. and stirred to dissolve the polyester. After the polyester was completely dissolved, a solution of a mixture of 20.0 parts of methacrylic acid and 5.0 parts of ethyl acrylate and 1.2 parts of azobisdimethylvaleronitrile in 25 parts of methyl ethyl ketone was added at 0.2 ml / min. Was dripped into the polyester solution and the stirring was continued for 2 hours after the completion of the dropping. After sampling for analysis (5 g) 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 of the obtained dispersion liquid was raised to 100 ° C., and methyl ethyl ketone, isopropyl alcohol and excess triethylamine were distilled off by distillation to prepare a dispersion liquid of the graft copolymer.

The resulting dispersion was white and had an average particle size of 20.
The B type viscosity at 0 nm and 25 ° C. was 90 cps. To 5 g of this dispersion was added 1.25 g of heavy water to make the solid content concentration 20% by weight, and then DSS was added to obtain 125 M.
Hz ¹³ C-NMR was measured. The FWHM of the carbonyl carbon signal of the polyester main chain (160 to 175 ppm) is ∞ (no signal is detected), and the carbonyl carbon signal of the branch polymer methacrylic acid (181
The full width at half maximum (ppm to 186 ppm) was 110 Hz. At the end of the grafting reaction, the sampled solution was dried under vacuum at 100 ° C. for 8 hours to determine the acid value of the solid content, measure the grafting efficiency of polyester (measurement of NMR), and branch polymer by hydrolysis. The molecular weight of was measured. Acid value of solid content is 2300e
q. It was / 106 g. ^{In 1} H-NMR measurement, a signal derived from fumaric acid (δ = 6.8 to 6.9 ppm,
Since doublet) was not detected at all, it was confirmed that the grafting efficiency of the polyester was 100%.
The weight average molecular weight of the branch polymer was 10,000.

A coating liquid was prepared by diluting the above dispersion liquid with water so that the solid content concentration was 10%. The polyamide was heated and melted at 260 ° C. by a screw type extruder and extruded from a T die. Then, this unstretched sheet is cooled by a drum 5
The film was longitudinally stretched 3.2 times at 0 ° C. A coating agent was applied to the obtained polyamide film substrate by a gravure method so that the coating amount was 4 g / m ² , and then dried so that the water content of the coated polyamide film was 1%, and then 120 ° C.
4 times transverse stretching and heat setting at 220 ℃, thickness 1
A 5 μm laminated polyamide film was obtained. The coating amount of the grafted polyester was 0.2 g / m ² .

An inorganic oxide layer was formed on the organic layer of the polyamide film having the organic layer obtained above by the following procedure.

As a vapor deposition material, a block obtained by mixing powders of silicon, silicon dioxide and silicon monoxide with a binder and incinerating them was used. This vapor deposition material block was placed on a water-cooled copper hearth and heated by an electron beam to evaporate.
The polyamide film having the organic material layer of the base material was set on the unwinding coal of the vapor deposition device and run on the vapor deposition source to form the inorganic oxide layer. This inorganic oxide layer is SiO
_{It was x} (x = 1.8). The thickness of the inorganic oxide layer is 50
nm.

A 55-μm-thick polyethylene film was dry-laminated to the obtained laminated polyamide film using a two-pack type polyurethane adhesive. A hamburger was put in during the making of a four-sided sealed bag using this polyamide film laminate, which was sterilized by microwaves and left at room temperature. After 30 days, the contents were opened and the contents were verified, but no change was observed.

[0121]

The laminated polyamide film of the present invention is a gas barrier film having excellent strength and transparency. Therefore, it can be used as a packaging material for foods, pharmaceuticals, electronic parts, and the like, and can be used as an electronic material such as a moisture-proof film for EL, which has great industrial utility value.

Front page continuation (72) Inventor Shigeru Yoneda 1-1-1, Katata, Otsu, Shiga Toyobo Co., Ltd. (72) Inventor Yozo Yamada 2-1-1 Katata, Otsu, Shiga Prefecture Toyobo Co., Ltd. Company Research Institute (72) Inventor Chika Morishige, 1-1 Katata, Otsu City, Shiga Prefecture Toyobo Co., Ltd. Research Institute

Claims (4)

[Claims] 1. A laminated polyamide film in which an organic material layer containing a graft copolymer of polyester and an acrylic polymer and an inorganic oxide layer are sequentially laminated on at least one surface of a polyamide film substrate. 2. The laminated polyamide film according to claim 1, wherein the glass transition point of the graft copolymer is 30 ° C. or lower. 3. The organic layer, after applying a coating liquid containing the graft copolymer to an unstretched polyamide film,
The laminated polyamide film according to claim 1 or 2, which is formed by biaxially stretching and heat-setting the coated film. 4. The organic layer, after applying a coating solution containing the graft copolymer to a uniaxially stretched polyamide film,
The laminated polyamide film according to any one of claims 1 to 3, which is formed by further uniaxially stretching and heat-setting the coated film.