JP2006219518A - Gas barrier coating and gas barrier laminate using the same coating - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas barrier coating without containing chlorine in the structure and without lowering gas barrier properties even when preserved at high-temperature and high-humidity conditions over a long period. <P>SOLUTION: The gas barrier coating is characterized as follows. The gas barrier coating comprises a polyalcoholic polymer (A), a polycarboxylic acid polymer (B), a compound (C) containing a polyvalent metal and a volatile base as constituent elements and an alkali metal compound (D). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a gas barrier coating having excellent gas barrier properties even when stored for a long time under high temperature and high humidity.

  Thermoplastic resin films such as polyamide film and polyester film are excellent in strength, transparency, and moldability, and thus are used in a wide range of applications as packaging materials. However, since these thermoplastic resin films have a large gas permeability such as oxygen, when they are used for packaging general foods, retort-treated foods, cosmetics, medical supplies, agricultural chemicals, etc., they have permeated the film during long-term storage. The contents may be altered by gases such as oxygen.

  Therefore, a laminated film in which a thermoplastic resin surface is coated with a polyvinylidene chloride (hereinafter abbreviated as PVDC) emulsion or the like to form a PVDC layer having a high gas barrier property has been widely used for food packaging and the like. However, since PVDC generates an organic substance such as acid gas during incineration, interest in the environment has increased in recent years, and a shift to other materials has been strongly desired.

  Polyvinyl alcohol (hereinafter abbreviated as PVA) as an alternative to PVDC does not generate toxic gas and has a high gas barrier property in a low humidity atmosphere. However, as the humidity increases, the gas barrier property decreases rapidly. In many cases, it cannot be used for packaging foods.

As a polymer that has improved the deterioration of gas barrier properties under high humidity of PVA, a copolymer of alcohol and ethylene (EVOH) is known. However, in order to maintain the gas barrier property at high humidity at a practical level, it is necessary to increase the copolymerization ratio of ethylene to some extent, and such a polymer is hardly soluble in water.
Therefore, in order to obtain a coating agent using EVOH having a high copolymerization ratio of ethylene, it is necessary to use an organic solvent or a mixed solvent of water and an organic solvent, which is not desirable from the viewpoint of environmental problems, and recovery of the organic solvent. Since a process etc. are required, there exists a problem that cost becomes high.

As a method of coating a film with a liquid composition comprising a water-soluble polymer and developing a high gas barrier property even under high humidity, the film is coated with an aqueous solution comprising a partially neutralized product of PVA and polyacrylic acid or polymethacrylic acid. Then, a method of crosslinking both polymers by ester bonds by heat treatment has been proposed (Patent Document 1: Japanese Patent Application Laid-Open No. 06-220221, Patent Document 2: JP 07-0102083, Patent Document 3: 07). No. -205379, Japanese Patent No. 07-266441, Japanese Patent No. 07-266441, Japanese Patent No. 08-041218, Japanese Patent No. 10-237180, etc.).
However, the method proposed in the above publication requires heat treatment at a high temperature or a long-time heat treatment in order to develop a high gas barrier property. Not a few.
In addition, heat treatment at a high temperature may cause discoloration or decomposition of PVA or the like constituting the gas barrier layer, and may cause deformation such as wrinkles on a base material such as a plastic film on which the gas barrier layer is laminated, resulting in a packaging material. Can no longer be used. In order to prevent the deterioration of the plastic substrate, it is necessary to use a special heat-resistant film that can sufficiently withstand high-temperature heating as a substrate, which is difficult in terms of versatility and economy.
On the other hand, when the heat treatment temperature is low, it is necessary to perform the treatment for a very long time, which causes a problem that productivity is lowered.

Further, studies have been made to solve the problems of the PVA film by introducing a crosslinked structure into PVA. However, in general, the humidity dependence of the oxygen gas barrier property of the PVA film decreases with an increase in the crosslinking density, but on the other hand, the oxygen gas barrier property under the dry conditions inherent to the PVA film decreases, resulting in a result. As such, it is very difficult to obtain a good oxygen gas barrier property under high humidity.
In general, water resistance is improved by cross-linking polymer molecules, but gas barrier property is a property that prevents the entry and diffusion of relatively small molecules such as oxygen, and gas barrier properties can be obtained by simply cross-linking polymers. For example, three-dimensional crosslinkable polymers such as epoxy resins and phenol resins do not have gas barrier properties.

  There has been proposed a method for providing a gas barrier laminate having a high gas barrier property even under high humidity while using a water-soluble polymer such as PVA by a heat treatment at a lower temperature or in a shorter time than conventional (Patent Document 7). : Japanese Patent Laid-Open No. 2001-323204, Patent Document 8: Japanese Patent Laid-Open No. 2002-020677, Patent Document 9: Japanese Patent Laid-Open No. 2002-241671).

The coating agent described in Patent Documents 7 to 9 uses a water-soluble polymer, but has a higher gas barrier than the conventional coating under high humidity at a lower temperature or in a shorter time than the coating agent described in Patent Documents 1 to 6. A gas barrier laminate having properties can be formed.
However, a gas barrier layer is formed only by the method described in Patent Documents 1 to 9 by esterifying the hydroxyl group in PVA and COOH in polyacrylic acid or ethylene-maleic acid copolymer by heating. When the film is stored under high temperature and high humidity for a long time, the ester bond is decomposed by hydrolysis, and the gas barrier property is remarkably deteriorated.

There has also been proposed a method for obtaining a gas barrier layer only by metal crosslinking between a polycarboxylic acid and a polyvalent metal without using PVA (Patent Document 10: JP-A-2004-511146).
Since the gas barrier layer described in Patent Document 10 does not have water resistance at high temperatures, the gas barrier layer is dissolved when boiled with hot water. In addition, gas barrier properties can be maintained even when exposed to high humidity near room temperature of about 20 to 30 ° C., but when exposed to high humidity at a high temperature of 40 ° C. or higher, deterioration of gas barrier properties is severe.
In addition, even if it boils with hot water etc. by overcoating the resin layer which has water resistance, it can prevent that a gas barrier layer melt | dissolves. However, when the barrier layer is exposed to high temperature and high humidity, the deterioration of the barrier property cannot be prevented.
As a result, the coating agents described in Patent Documents 1 to 10 could not meet more stringent requirements.
Japanese Patent Laid-Open No. 06-220221 Japanese Patent Application Laid-Open No. 07-102083 Japanese Patent Application Laid-Open No. 07-205379 Japanese Patent Application Laid-Open No. 07-266441 Japanese Patent Application Laid-Open No. 08-041218 Japanese Patent Laid-Open No. 10-237180 JP 2001-323204 A JP 2002-020677 A JP 2002-241671 A JP 2004-511146 A

  The subject of this invention is providing the gas-barrier coating material and gas-barrier laminated body which can maintain gas-barrier property even if it preserve | saves for a long time at high temperature and high humidity.

As a result of intensive studies, the present inventors have found that gas barrier properties can be maintained even when stored for a long time at high temperature and high humidity by using a specific polyvalent metal compound, a polyalcohol polymer, and a polycarboxylic acid polymer. The present invention has been reached.
That is, the present invention contains a polyalcohol-based polymer (A), a polycarboxylic acid-based polymer (B), a compound (C) having a polyvalent metal and a volatile base as constituent elements, and an alkali metal compound (D). The present invention relates to a gas barrier paint characterized by the above.

The compound (C) comprising a polyvalent metal and a volatile base comprises NH ₃ as a constituent element, and relates to the gas barrier coating composition as described above.

  Furthermore, the polyalcohol-based polymer (A) is any one of polyvinyl alcohol, an ethylene-vinyl alcohol copolymer, a saccharide, or a mixture thereof.

Furthermore, the polycarboxylic acid polymer (B) is an olefin-maleic acid copolymer, the gas barrier paint according to any one of the above,
Further, the present invention relates to the gas barrier coating composition as described above, wherein the olefin-maleic acid copolymer is an ethylene-maleic acid copolymer.

  Furthermore, the polyvalent metal is zinc, which relates to any one of the above gas barrier coatings.

  Furthermore, the alkali metal compound (D) is an alkali metal hydroxide, and relates to any one of the above gas barrier paints.

  Furthermore, the gas barrier layer formed from the gas barrier coating material according to any one of the above, is laminated directly on the plastic substrate or on the plastic substrate via an undercoat layer. To body.

  According to the present invention, it was possible to provide a gas barrier coating material that does not contain chlorine in the structure and has excellent gas barrier properties even when stored for a long time under high temperature and high humidity.

Hereinafter, the present invention will be described in detail.
<Polyalcohol-based polymer (A)>
The polyalcohol polymer (A) used in the present invention is a polymer having two or more hydroxyl groups in the molecule, such as PVA, ethylene-vinyl alcohol copolymer, saccharides, polyhydroxyethyl (meth) acrylate, poly Examples thereof include a polymer obtained by polymerizing a monomer having a hydroxyl group such as glycerin (meth) acrylate.

<PVA>
The PVA used in the present invention can be obtained by a known method such as complete or partial saponification of a vinyl ester polymer.
Examples of the vinyl ester include vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate, vinyl versatate, etc. Among them, vinyl acetate is industrially most preferable.

  It is also possible to copolymerize other vinyl compounds with the vinyl ester as long as the effects of the present invention are not impaired. Other vinyl monomers include unsaturated monocarboxylic acids such as crotonic acid, acrylic acid, and methacrylic acid and their esters, salts, anhydrides, amides, nitriles, and unsaturated acids such as maleic acid, itaconic acid, and fumaric acid. Examples thereof include dicarboxylic acids and salts thereof, α-olefins having 2 to 30 carbon atoms, alkyl vinyl ethers, vinyl pyrrolidones and the like.

  In the present invention, the polymer laminated for imparting gas barrier properties to the film surface is preferably water-soluble for production, and if a large amount of a hydrophobic copolymer component is contained, the water-solubility is impaired.

  As a saponification method, a known alkali saponification method or acid saponification method can be used, and among them, a method of decomposing alcohol using an alkali hydroxide in methanol is preferable. The degree of saponification is preferably closer to 100% from the viewpoint of gas barrier properties, and if the degree of saponification is too low, the gas barrier performance is lowered. The saponification degree is usually preferably about 95% or more, more preferably 98% or more. The average degree of polymerization is preferably 50 to 4000, and more preferably 200 to 3000.

<Sugar>
Examples of sugars (also referred to as carbohydrates) include monosaccharides, disaccharides, oligosaccharides, and polysaccharides. These saccharides include sugar alcohols and various substitutes and derivatives. These saccharides are preferably water-soluble.

Monosaccharides are constituents of disaccharides, oligosaccharides and polysaccharides, and are usually represented by C _m (H ₂ O) _n . Examples of monosaccharides include glucose, galactose, talose, mannose, sorbose, tagatose, fructose, psicose, erythrose, threose, erythrulose, arabinose, xylose, ribose, lyxose, ribulose and the like.

  In addition, disaccharides are those in which two monosaccharides are glycosylated, and examples thereof include maltose, lactose, sucrose, cellobiose, treperth, gentiobiose, isomaltose and the like.

  Oligosaccharides are those in which 3 to 6 monosaccharides are glycosylated and include, for example, raffinose and gentianose. Furthermore, the polysaccharide is a polymer compound in which 7 or more monosaccharides are polyglycosylated, and examples thereof include cellulose, starch, pullulan, glycogen, inulin, dextran, chitin and the like, and pullulan is preferable.

  Furthermore, the sugar alcohol is a polyhydroxyalkane obtained by reducing a monosaccharide, and examples thereof include sorbitol, mannitol, dulcitol, xylitol, erythritol, and glycerol.

  Furthermore, the saccharide derivative means esterification, carboxymethylation, acetylation, phosphorylation, carboxylation, amination, allyl etherification, methyl etherification, carboxymethyl etherification, grafting, etc. on the above saccharide. It has been subjected to substitution or modification.

  As monomers for graft polymerization with respect to the saccharide, unsaturated monocarboxylic acids such as crotonic acid, acrylic acid, and methacrylic acid and esters thereof, salts, anhydrides, amides, nitriles, maleic acid, itaconic acid, Examples thereof include unsaturated dicarboxylic acids such as fumaric acid and salts thereof, α-olefins having 2 to 30 carbon atoms, alkyl vinyl ethers, vinyl pyrrolidones and the like.

  The disaccharide, oligosaccharide, polysaccharide, or derivative thereof may be composed of one type of monosaccharide or may be composed of two or more types of monosaccharide. The above saccharides can be used alone or in combination of two or more.

<Polymer formed by polymerizing a monomer having a hydroxyl group>
Examples of the polymer obtained by polymerizing a monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. , 3-hydroxybutyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, glycerin (meth) acrylate, polyethylene glycol mono (meth) acrylate (preferably having a repetition of CH ₂ CH ₂ O units of 1 to 6) And a homopolymer obtained by individually polymerizing a hydroxyl-terminated urethane (meth) acrylate, a copolymer obtained by copolymerizing a plurality of monomers, and a copolymer obtained by copolymerizing with other monomers. The former two, that is, a homopolymer, a copolymer of monomers having a hydroxyl group and an ethylenically unsaturated double bond, are preferred, and the coating material for forming a gas barrier of the present invention comprises two or more homopolymers, or a hydroxyl group and an ethylenically unsaturated two bond. Two or more copolymers of monomers having a heavy bond can be contained. Furthermore, homopolymers and copolymers can also be contained.

As another monomer that can be copolymerized with a monomer having a hydroxyl group, a monomer that does not have a hydroxyl group or a carboxyl group and that can be copolymerized with a monomer having a hydroxyl group can be appropriately used.
For example, C1-C30 alpha-alpha, such as crotonic acid, unsaturated monocarboxylic acid ester, such as (meth) acrylic acid, (meth) acrylamide, (meth) acrylonitrile, styrene, styrenesulfonic acid, vinyltoluene, ethylene Examples include olefins, alkyl vinyl ethers, and vinyl pyrrolidone.

  Said polyalcohol-type polymer (A) can be used individually or in combination of 2 types or more, respectively.

<Polycarboxylic acid polymer (B)>
The polycarboxylic acid polymer (B) used in the present invention is a polymer having two or more carboxyl groups or acid anhydride groups in the molecule, and is formed by polymerizing monomers having carboxyl groups or acid anhydride groups. Polymer, and the like.
Examples of the monomer having a carboxyl group or an acid anhydride group include (meth) acrylic acid, 2-carboxyethyl (meth) acrylate, ω-carboxy-polycaprolactone monoacrylate, maleic acid, maleic anhydride, fumaric acid, anhydrous Examples thereof include fumaric acid, citraconic acid, citraconic anhydride, itaconic acid and itaconic anhydride, and (meth) acrylic acid, maleic acid, maleic anhydride, itaconic acid and itaconic anhydride are preferred.

  Examples of the polycarboxylic acid-based polymer (B) include homopolymers obtained by polymerizing these monomers alone, copolymers obtained by copolymerizing plural monomers, and copolymers obtained by copolymerizing with other monomers.

Other monomers that can be copolymerized with a monomer having a carboxyl group or an acid anhydride group include monomers that do not have a hydroxyl group or a carboxyl group and that can be copolymerized with a monomer that has a carboxyl group or an acid anhydride group. It can be used as appropriate.
For example, C1-C30 alpha-alpha, such as crotonic acid, unsaturated monocarboxylic acid ester, such as (meth) acrylic acid, (meth) acrylamide, (meth) acrylonitrile, styrene, styrenesulfonic acid, vinyltoluene, ethylene Examples include olefins, alkyl vinyl ethers, and vinyl pyrrolidone.

  Specific examples of the polycarboxylic acid polymer (B) include polyacrylic acid, polymethacrylic acid, polymaleic acid, polyitaconic acid, acrylic acid-methacrylic acid copolymer, and olefin-maleic represented by ethylene-maleic anhydride. Examples include acid copolymers, and polyacrylic acid, polyitaconic acid, and olefin-maleic acid copolymers are preferable, and poly (meth) acrylic acid and ethylene-maleic anhydride copolymers are more preferable.

  Said polycarboxylic acid type polymer (B) can be used individually or in combination of 2 or more types, respectively.

<Olefin-maleic acid copolymer>
The olefin-maleic acid copolymer in the present invention can be obtained by copolymerizing maleic anhydride or maleic acid and an olefin monomer by a known method such as radical polymerization in a solution.

  Examples of the olefin monomer copolymerizable with maleic anhydride include alkyl vinyl ethers having 3 to 30 carbon atoms such as methyl vinyl ether and ethyl vinyl ether, methyl (meth) acrylate, ethyl (meth) acrylate, and (meth) acrylic acid. (Meth) acrylic acid esters such as butyl, vinyl esters such as vinyl formate and vinyl acetate, olefins having 2 to 30 carbon atoms such as styrene, p-styrene sulfonic acid, ethylene, propylene and isobutylene, hydroxyl groups of PVA, etc. Examples thereof include a compound having a reactive group to be reacted, and a mixture thereof can also be used.

  Of these, alkyl vinyl ethers and lower olefins are preferable from the viewpoint of improving gas barrier properties, and methyl vinyl ether, isobutylene and ethylene are particularly preferable.

The maleic acid unit in the olefin-maleic acid copolymer is likely to have a maleic anhydride structure in which the adjacent carboxyl group is dehydrated and cyclized in a dry state, and opens to form a maleic acid structure when wet or in an aqueous solution.
Therefore, in the present invention, unless otherwise specified, maleic acid units and maleic anhydride units are collectively referred to as maleic acid units.

The maleic acid unit in the olefin-maleic acid copolymer in the present invention is preferably contained in an amount of 10 mol% or more, more preferably 35 mol% or more. A copolymer with an acid is more preferred. When the maleic acid unit is less than 10 mol%, formation of a crosslinked structure by reaction with the polyalcohol polymer (A) tends to be insufficient, and gas barrier properties tend to be lowered. The maleic acid unit may be partially esterified or amidated.
The olefin-maleic acid copolymer used in the present invention preferably has a weight average molecular weight of 3000 to 1000000, more preferably 5000 to 900000, and still more preferably 10000 to 800000.

<Ethylene-maleic acid copolymer>
The ethylene-maleic acid copolymer (hereinafter referred to as EMA) used in the present invention is obtained by polymerizing maleic anhydride and ethylene by a known method such as solution radical polymerization. It is also possible to copolymerize a small amount of other vinyl compounds as long as the object of the present invention is not impaired. Examples of vinyl compounds include acrylic acid esters such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate and butyl methacrylate, vinyl esters such as vinyl formate and vinyl acetate, Examples thereof include compounds having a reactive group that reacts with olefins having 3 to 30 carbon atoms such as styrene, p-styrenesulfonic acid, propylene and isobutylene, and hydroxyl groups of PVA.

The maleic acid unit in the EMA in the present invention is preferably contained in an amount of 10 mol% or more, and an alternating copolymer of ethylene and maleic anhydride having approximately equimolar maleic acid units is preferred. When the maleic acid unit is less than 10 mol%, the formation of a crosslinked structure by the reaction with the polyalcohol polymer (A) is insufficient and the gas barrier property is lowered.
Moreover, it is preferable that the weight average molecular weights of EMA used by this invention are 3000-1 million, It is more preferable that it is 5000-900000, It is still more preferable that it is 10000-800000.

  Incidentally, the maleic acid unit in the EMA used in the present invention tends to have a maleic anhydride structure in which the adjacent carboxyl group is dehydrated and cyclized in a dry state, while it is ring-opened to form a maleic acid structure when wet or in an aqueous solution. .

  In the gas barrier coating used in the present invention, the weight ratio of the polyalcohol polymer (A) to the polycarboxylic acid polymer (B) is polyalcohol polymer / polycarboxylic acid polymer = 90/10 to 10/90. It is preferably 70/30 to 15/85, more preferably 60/40 to 20/80, and particularly preferably 50/50 to 25/75. If any of the polymers is relatively excessive, the effect of improving the gas barrier property is small.

<Compound (C) comprising polyvalent metal and volatile base as constituent elements>
The compound (C) comprising a polyvalent metal and a volatile base used in the present invention is a compound of a polyvalent metal and a volatile base such as ammonia or amine, which is a polyvalent metal ammonia. Complexes, amine complexes, ammonium carbonate complexes, and the like can be mentioned, and ammonia complexes and ammonium carbonate complexes with less volatile base remaining in the gas barrier laminate upon curing of the gas barrier coating are preferred.

  Normally, when polycarboxylic acid polymer (B) is mixed with polyvalent metal compounds such as oxides, chlorides and carbonates of polyvalent metals, aggregation of polycarboxylic acid polymers occurs due to the reaction of carboxylic acids and polyvalent metals. easy. However, by using the compound (C) having the polyvalent metal and the volatile base of the present invention as constituent elements, the polyvalent metal does not react with the carboxylic acid and aggregation does not occur. When the gas barrier paint of the present invention is applied and then heated, the compound (C) containing the polyvalent metal and the volatile base is decomposed, the volatile base is volatilized, and the polyvalent metal and the carboxylic acid are decomposed. React to form a metal cross-linked structure.

<Multivalent metal>
Examples of the polyvalent metal used in the present invention include alkaline earth metals such as beryllium, calcium and magnesium, transition metals such as nickel, copper, chromium, zirconium, manganese and iron, and aluminum, and ammonia such as zinc and zirconium. The metal which reacts with is preferable, and especially zinc is preferable.

<Volatile base>
Examples of the volatile base used in the present invention include methanolamine, methylmethanolamine, dimethylmethanolamine, ethylmethanolamine, diethylmethanolamine, methylethylmethanolamine, ethanolamine, methylethanolamine, dimethylethanolamine, and ethylethanolamine. , Amines that can form complex structures with metals such as diethylethanolamine, methylethylethanolamine, dimethanolamine, methyldimethanolamine, ethyldimethanolamine, diethanolamine, methyldiethanolamine, ethyldiethanolamine, trimethanolamine, triethanolamine And ammonia, and ammonia is particularly preferable.

  The compound (C) having a polyvalent metal and a volatile base as constituent elements may contain a constituent element other than the polyvalent metal and the volatile base, and examples thereof include carbonic acid.

Specific examples of the compound (C) having a polyvalent metal and a volatile base as constituent elements include ammonium zinc, ammonium copper, ammonium zinc carbonate, ammonium zirconium carbonate and the like, and ammonium zinc and ammonium zinc carbonate are preferable.
The compound (C) having a polyvalent metal and a volatile base as constituent elements may be used alone or in combination of two or more.
In addition, the compound (C) having a polyvalent metal and a volatile base as constituents can be compounded with a compound (C) having a polyvalent metal and a volatile base as constituents, or A polyvalent metal compound capable of forming a compound (C) having a polyvalent metal and a volatile base as constituents and a volatile base can also be blended in the paint.

The addition amount of the compound (C) having a polyvalent metal and a volatile base as constituent elements is preferably 0.2 to 15 chemical equivalents relative to the carboxylic acid of the polycarboxylic acid polymer (B). 10 to 10 chemical equivalents are particularly preferred.
When the amount is less than 0.2 chemical equivalent, the barrier property is insufficient, and when the amount is more than 15 chemical equivalents, the water resistance tends to deteriorate. The chemical equivalent here is a chemical equivalent of the polycarboxylic acid polymer (B) to the carboxylic acid. One chemical equivalent refers to the amount of base that neutralizes one equivalent of carboxylic acid acting as an acid. Here, the base is a polyvalent metal constituting the compound (C) having a polyvalent metal and a volatile base as constituent elements. For example, when the polyvalent metal is zinc, since zinc is a divalent metal, carboxylic acid and zinc react at a ratio of 2: 1 mol, and 0.2 mol is added when 0.1 mol of zinc is added to 1 mol of carboxylic acid. The chemical equivalent is 1 chemical equivalent when 0.5 mol of zinc is added and 15 chemical equivalents when 7.5 mol of zinc is added.

<Alkali metal compound (D)>
The alkali metal compound (D) used in the present invention is a compound such as a hydroxide, oxide or carbonate of an alkali metal such as lithium, sodium or potassium. Sodium and potassium hydroxide are particularly preferred.

  As addition amount of an alkali metal compound (D), 0.001-0.6 mol% neutralization amount is preferable with respect to the carboxylic acid of a polycarboxylic acid type polymer (A), and 0.002-0.5 mol% neutralization is preferable. The amount is particularly preferred. When the amount is less than 0.001 mol% neutralization, the barrier property is insufficient, and when the amount is more than 0.6 mol% neutralization, the water resistance is deteriorated.

  The carboxylic acid of the polycarboxylic acid polymer (B) may be reacted with other compounds within a range that does not affect the performance such as barrier properties and water resistance. Polyvalent metals other than the compound (C) having a polyvalent metal and a volatile base as constituents, such as magnesium, calcium, barium, zinc, aluminum, cobalt, tin, iron, titanium, copper, nickel oxide, manganese, etc. Dihydric or higher polyvalent metal hydroxides, sulfides, oxides, carbonates, acetates, oxides, phosphorus oxides, nitrates, chlorides, ammonia, methylamine, ethylamine, butylamine, dimethylamine, diethylamine , Alkylamines such as dibutylamine, trimethylamine, triethylamine, and tributylamine, alcohol amines such as dimethylaminoethanol, diethanolamine, ethanolamine, and aminomethylpropanol, cyclic amines such as morpholine, and polyvalent amines such as ethylenediamine .

The gas barrier layer-forming coating material used in the present invention may further contain an inorganic layered compound. By containing the inorganic layered compound, the gas barrier properties of the gas barrier layer and the gas barrier laminate can be further improved.
From the viewpoint of gas barrier properties, it is preferable that the content of the inorganic layered compound is large. However, inorganic layered compounds have strong water affinity and are easy to absorb moisture. Moreover, since the coating material containing an inorganic layered compound tends to increase in viscosity, it tends to impair paintability. Furthermore, when there is much content of an inorganic layered compound, the transparency of the gas barrier layer and gas barrier layered product formed will fall.
Therefore, from these viewpoints, the inorganic layered compound is preferably 1 to 300 parts by weight, and 2 to 200 parts by weight with respect to a total of 100 parts by weight of the polyalcohol-based polymer and the polycarboxylic acid-based polymer. More preferred is at most 100 parts by weight.

The inorganic layered compound here is an inorganic compound in which unit crystal layers overlap to form a layered structure, and particularly those that swell and cleave in a solvent.
Preferred examples of the inorganic layered compound include montmorillonite, beidellite, saponite, hectorite, soconite, vermiculite, fluorine
Mica, muscovite, paragonite, phlogopite, biotite, lepidrite, margarite, clintnite, anandite, chlorite, donbasite, sudite, kukuite, clinochlore, chamosite, nimitite, tetrasilic mica, talc, pyrophyllite , Nacrite, kaolinite, halloysite, chrysotile, sodium teniolite, xanthophyllite, antigolite, dickite, hydrotalcite and the like, and swellable fluoromica or montmorillonite is particularly preferred.

  These inorganic layered compounds may be naturally occurring, artificially synthesized or modified, or those treated with an organic material such as an onium salt.

The swellable fluoromica mineral is most preferable in terms of whiteness, and is represented by the following formula.
α (MF) · β (aMgF ₂ · bMgO) · γSiO ₂ (wherein M represents sodium or lithium, α, β, γ, a and b each represents a coefficient, 0.1 ≦ α ≦ 2, 2 ≦ β ≦ 3.5, 3 ≦ γ ≦ 4, 0 ≦ a ≦ 1, 0 ≦ b ≦ 1, and a + b = 1.)

  As a method for producing such a swellable fluorinated mica-based mineral, for example, silicon oxide, magnesium oxide, and various fluorides are mixed, and the mixture is completely heated in an electric furnace or gas furnace at a temperature range of 1400 to 1500 ° C. There is a so-called melting method in which a fluoric mica-based mineral is crystal-grown in a reaction vessel during the cooling process.

  Further, there is a method of using a talc as a starting material and intercalating an alkali metal ion thereto to obtain a swellable fluoromica-based mineral (Japanese Patent Laid-Open No. 2-149415). In this method, a swellable fluoromica-based mineral can be obtained by mixing talc with an alkali silicofluoride or an alkali fluoride and subjecting it to a heat treatment at about 700 to 1200 ° C. for a short time in a magnetic crucible.

  At this time, the amount of alkali silicofluoride or alkali fluoride mixed with talc is preferably in the range of 10 to 35% by weight of the entire mixture. This is not preferable because the yield decreases.

  The alkali metal silicofluoride or alkali metal is preferably sodium or lithium. These alkali metals may be used alone or in combination. In addition, among alkali metals, in the case of potassium, a swellable fluoromica-based mineral cannot be obtained, but it can be used in combination with sodium or lithium, and for the purpose of adjusting the swellability in a limited amount. It is.

  Furthermore, in the process of producing the swellable fluoromica-based mineral, it is also possible to adjust the swelling property of the swellable fluoromica-based mineral to be produced by blending a small amount of alumina.

Montmorillonite is represented by the following formula and can be obtained by purifying a naturally occurring product.
M _a Si ₄ (Al _{2 -a} Mg _a ) O ₁₀ (OH) ₂ .nH ₂ O (wherein M represents a cation of sodium and a is 0.25 to 0.60. Further, an ion-exchange cation between layers) (The number of water molecules bonded to each other can be changed depending on the conditions such as the cation species and humidity, and is represented by nH ₂ O in the formula.)
In addition, montmorillonite also includes the same type of ion substitution products of magnesia montmorillonite, iron montmorillonite, and iron magnesia montmorillonite represented by the following formula group, and these may be used.
M _a Si ₄ (Al _1.67-a Mg _{0.5 + a} ) O ₁₀ (OH) ₂ .nH ₂ O
M _a Si ₄ (Fe (III) _2-a Mg _a ) O ₁₀ (OH) ₂ .nH ₂ O
M _a Si ₄ (Fe (III) _1.67-a Mg _{0.5 + a} ) O ₁₀ (OH) ₂ .nH ₂ O
(In the formula, M represents a cation of sodium, and a is 0.25 to 0.60.)

  Usually, montmorillonite has ion-exchangeable cations such as sodium and calcium between its layers, but the content ratio varies depending on the production area. In the present invention, it is preferable that the ion exchange cation between layers is replaced with sodium by ion exchange treatment or the like. Moreover, it is preferable to use montmorillonite purified by water treatment.

  The inorganic layered compound can be directly mixed with the polyalcohol-based polymer (A) and the polycarboxylic acid-based polymer (B), but is preferably swollen and dispersed in a liquid medium in advance before mixing. The liquid medium for swelling and dispersing is not particularly limited. For example, in the case of natural swelling clay minerals, alcohols such as water, methanol, ethanol, propanol, isopropanol, ethylene glycol, diethylene glycol, dimethylformamide, dimethyl sulfoxide Acetone and the like, and alcohols such as water and methanol are more preferable.

  In the gas barrier coating composition according to the present invention, a heat stabilizer, an antioxidant, a reinforcing material, a pigment, a deterioration preventing agent, a weathering agent, a flame retardant, a plasticizer, a release agent, and a lubricant are used as long as the characteristics are not greatly impaired. Etc. may be added.

  Examples of the heat stabilizer, antioxidant, and deterioration inhibitor include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, alkali metal halides, and mixtures thereof.

Next, the manufacturing method of the gas barrier coating material in this invention is demonstrated.
For example, a method in which the polyalcohol polymer (A) and the polycarboxylic acid polymer (B) are separately made into aqueous solutions and mixed before use is preferable. And as a method to add the compound (C) and alkali metal compound (D) which use a polyvalent metal and a volatile base as a component, the method shown to (1)-(10) is mentioned, for example. ) To (4) are preferred.
(1) A compound (C) having a polyvalent metal and a volatile base as constituents is mixed with either a polyalcohol polymer (A) or a polycarboxylic acid polymer (B), and then an alkali metal Compound (D) is mixed, and further polycarboxylic acid polymer (B) or polyalcohol polymer (A) is mixed.
Alternatively, the compound (C) having a polyvalent metal and a volatile base as constituent elements is mixed with either the polyalcohol polymer (A) or the polycarboxylic acid polymer (B), and then the alkali metal compound. (D) and a polycarboxylic acid polymer (B) or an alkali metal compound (D) and a polyalcohol polymer (A) are mixed.
(2) Compound (C) having polyvalent metal and volatile base as constituent elements is mixed with a mixture of polyalcohol polymer (A) and polycarboxylic acid polymer (B), and then alkali metal compound ( D) is mixed.
(3) A compound (C) having a polyvalent metal and a volatile base as constituents, a mixture of a polyalcohol polymer (A) and an alkali metal compound (D), or a polycarboxylic acid polymer (B) and an alkali It mixes with either of the mixture of a metal compound (D), and also mixes a polycarboxylic acid type polymer (B) or a polyalcohol type polymer (A).
(4) Compound (C) having polyvalent metal and volatile base as constituent elements is mixed with a mixture of polyalcohol-based polymer (A), polycarboxylic acid-based polymer (B) and alkali metal compound (D). To do.
(5) Mixing a mixture of the polyalcohol-based polymer (A) and the polycarboxylic acid-based polymer (B) and a volatile base compound, then mixing the polyvalent metal compound, A compound (C) having a volatile base as a constituent element is obtained, and then an alkali metal compound (D) is mixed.
(6) After mixing the polyalcohol-based polymer (A) and the volatile base compound, the polyvalent metal compound is then mixed, and the compound (C) containing the polyvalent metal and the volatile base in the solution as a constituent element After that, the polycarboxylic acid polymer (B) and the alkali metal compound (D) are mixed.
(7) Compound (C) comprising a polycarboxylic acid polymer (B) and a volatile base compound, then a polyvalent metal compound, and a polyvalent metal and a volatile base as constituents in the solution. After that, the polyalcohol polymer (A) and the alkali metal compound (D) are mixed.
(8) Obtain a mixture of the polyalcohol-based polymer (A) and the alkali metal compound (D), then mix the volatile base compound, mix the polyvalent metal compound, and volatilize the polyvalent metal in the coating solution. Compound (C) having a functional base as a constituent element. The polycarboxylic acid-based polymer (B) may be added before adding the volatile base compound, or may be added at the same time, or after adding the volatile base compound and before adding the polyvalent metal compound. It may be added at the same time as the polyvalent metal compound or after the polyvalent metal compound is added.
(9) Obtain a mixture of the polycarboxylic acid polymer (B) and the alkali metal compound (D), then mix the volatile base compound, mix the polyvalent metal compound, and volatilize the polyvalent metal in the coating solution. Compound (C) having a functional base as a constituent element. The polyalcohol polymer (A) may be added before adding the volatile base compound, or may be added at the same time, or after adding the volatile base compound and before adding the polyvalent metal compound. It may be added at the same time as the polyvalent metal compound or after the polyvalent metal compound is added.
(10) After obtaining a mixture of the polyalcohol-based polymer (A), the polycarboxylic acid-based polymer (B), and the alkali metal compound (D), the volatile base compound is mixed, and the polyvalent metal compound is further mixed. A compound (C) having a polyvalent metal and a volatile base as constituents in the coating solution is used.

  The concentration (= solid content) of the gas barrier coating can be changed as appropriate depending on the specifications of the coating equipment and drying / heating equipment, but in a too dilute solution, a layer with a thickness sufficient to develop gas barrier properties can be coated. It is difficult to do this, and the problem that a long time is required in the subsequent drying process tends to occur. On the other hand, if the concentration of the gas barrier coating is too high, it is difficult to obtain a uniform coating, and problems with coating properties are likely to occur. From such a viewpoint, the concentration (= solid content) of the gas barrier coating is preferably in the range of 5 to 50% by weight.

[ Plastic substrate]
Gas barrier laminate with excellent moisture resistance by applying the above-mentioned gas barrier coating directly on the plastic substrate or on the plastic substrate through an undercoat layer (hereinafter also referred to as UC layer) and heat-treating it. You can get a body.
The plastic substrate used here is not only a film-like substrate manufactured from a thermoplastic resin that can be thermoformed by means such as extrusion molding, injection molding, blow molding, stretch blow molding, or draw molding, but also bottles and cups. Further, it may be a base material having various container shapes such as a tray, and is preferably in the form of a film.
Further, the plastic substrate may be composed of a single layer, or may be composed of a plurality of layers by, for example, simultaneous melt extrusion or other lamination.

  Examples of the thermoplastic resin constituting the plastic substrate include olefinic copolymers, polyesters, polyamides, styrene copolymers, vinyl chloride copolymers, acrylic copolymers, polycarbonates, and the like. Polymers, polyesters and polyamides are preferred.

Olefin-based copolymers include low-, medium- or high-density polyethylene, linear low density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-butene-copolymer, ionomer, ethylene-vinyl acetate copolymer. Coalesce, ethylene-vinyl alcohol copolymer, etc.
Examples of polyester include polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate / isophthalate, polyethylene naphthalate,
Examples of polyamides include polyamides such as nylon 6, nylon 6,6, nylon 6,10, and metaxylylene adipamide;
Examples of the styrene copolymer include polystyrene, styrene-butadiene block copolymer, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer (ABS resin), and the like.
Examples of the vinyl chloride copolymer include polyvinyl chloride, vinyl chloride-vinyl acetate copolymer,
Examples of the acrylic copolymer include polymethyl methacrylate and methyl methacrylate / ethyl acrylate copolymer.
These thermoplastic resins may be used alone or in combination of two or more.

The melt-moldable thermoplastic resin may contain one or more additives such as pigments, antioxidants, antistatic agents, ultraviolet absorbers, lubricants, etc. as required per 100 parts by weight of the resin. The amount can also be added in the range of 0.001 to 5.0 parts.
In addition, when forming a packaging material as described later using the gas barrier laminate of the present invention, in order to ensure the strength as a packaging material, various reinforcing materials are included as a plastic substrate constituting the gas barrier laminate. Can be used. That is, one of fiber reinforcing materials such as glass fiber, aromatic polyamide fiber, carbon fiber, pulp, cotton and linter, powder reinforcing material such as carbon black and white carbon, or flaky reinforcing material such as glass flake and aluminum flake. Two or more types can be blended in a total amount of 2 to 150 parts by weight per 100 parts by weight of the thermoplastic resin, and heavy or soft calcium carbonate, mica, talc, kaolin, gypsum for the purpose of further increase. One or more of clay, barium sulfate, alumina powder, silica powder, magnesium carbonate, etc. are blended according to a formulation known per se in a total amount of 5 to 100 parts by weight per 100 parts by weight of the thermoplastic resin. It doesn't matter.
Furthermore, with the aim of improving gas barrier properties, a prescription known per se in the amount of 5 to 100 parts by weight as a total amount of scaly inorganic fine powders such as water-swellable mica and clay per 100 parts by weight of the thermoplastic resin There is no problem even if it is blended according to.

[Undercoat layer]
The gas barrier coating material of the present invention is applied directly on a plastic substrate or on a plastic substrate via a UC layer and heat-treated. Therefore, the UC layer used in the present invention will be described. The UC layer is located between the gas barrier layer and the plastic substrate, and mainly plays a role in improving the adhesion of the gas barrier layer.
The UC layer can be formed from various polymers such as urethane, polyester, acrylic, and epoxy, and a urethane UC layer is preferred.

For example, in the case of a urethane-based UC layer,
(1) A UC composition containing a polyol component such as polyester polyol or polyether polyol and a polyisocyanate component is coated on a plastic substrate and heated to react the polyol component with the polyisocyanate component, thereby producing a urethane system. UC layers can be formed. By applying a gas barrier coating solution on the UC layer and heating it, a laminate comprising a substrate / UC layer / gas barrier layer can be obtained.
(2) A UC composition is coated on a plastic substrate and dried to obtain a precursor of the UC layer in which the reaction between the polyol component and the polyisocyanate component is not completed, and a gas barrier coating material is formed on the precursor. The base material / UC layer / gas barrier layer can also be obtained by coating the solution and heating to form the UC layer and the gas barrier layer at the same time.
(3) Alternatively, after applying the UC composition on the plastic substrate, without applying heating, the gas barrier coating is applied and heated to form the UC layer and the gas barrier layer at the same time. Thus, a laminate comprising a substrate / UC layer / gas barrier layer can also be obtained.
The polyisocyanate contained in the UC composition reacts with the hydroxyl groups in the polyalcohol-based polymer (A) in the interface region with the gas barrier layer to contribute to the improvement of adhesion, and also assists in crosslinking of the gas barrier layer, Therefore, the methods (2) and (3) are preferable.

As the polyol component used for forming the UC layer, a polyester polyol is preferable, and the polyester polyol is obtained by reacting a polyvalent carboxylic acid or a dialkyl ester thereof or a mixture thereof with a glycol or a mixture thereof. And polyester polyols that can be used.
Examples of the polyvalent carboxylic acid include aromatic polyvalent carboxylic acids such as isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acid, and aliphatic polyvalent carboxylic acids such as adipic acid, azelaic acid, sebacic acid, and cyclohexanedicarboxylic acid.
Examples of the glycol include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, neopentyl glycol, and 1,6-hexanediol.

These polyester polyols preferably have a glass transition temperature (hereinafter referred to as Tg) of −50 ° C. to 120 ° C., more preferably −20 ° C. to 100 ° C., and still more preferably 0 ° C. to 90 ° C. The suitable Tg of the polyester polyol is also related to the heat curing conditions when the gas barrier coating is applied and cured after heating. When heat-curing at a relatively low temperature, a polyester polyol having a relatively high Tg is preferable. When heat-curing at a relatively high temperature, a polyester polyol having a relatively wide Tg from a low temperature to a high temperature can be suitably used. For example, when the gas barrier coating is heated and cured at 180 ° C., a polyester polyol having a Tg of about 70 to 90 ° C. is preferable. On the other hand, when the gas barrier paint is heated and cured at 200 ° C., a polyester polyol having a Tg of about 0 to 90 ° C. can be used.
The number average molecular weight of these polyester polyols is preferably from 1,000 to 100,000, more preferably from 3,000 to 50,000, and even more preferably from 10,000 to 40,000.

As polyisocyanate used for forming the UC layer,
For example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'- Diphenylmethane diisocyanate, 3,3′-dimethyl-4,4′-biphenylene diisocyanate, 3,3′-dimethoxy-4,4′-biphenylene diisocyanate, 3,3′-dichloro-4,4′-biphenylene diisocyanate, Aromatic polyisocyanates such as 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate,
Tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, Aliphatic polyisocyanates such as 4,4′-dicyclohexylmethane diisocyanate, 3,3′-dimethyl-4,4′-dicyclohexylmethane diisocyanate,
It contains terminal isocyanate groups obtained by reaction with polyfunctional polyisocyanate compounds such as isocyanurates, burettes and allophanates derived from the above polyisocyanate monomers, or trifunctional or higher functional polyol compounds such as trimethylolpropane and glycerin. A polyfunctional polyisocyanate compound etc. can be mentioned. A trifunctional isocyanurate which is a trimer of hexamethylene diisocyanate (hereinafter also referred to as HMDI) is preferable.

  The weight ratio of polyester polyol to polyisocyanate is preferably 10:90 to 99: 1, more preferably 30:70 to 90:10, and even more preferably 50:50 to 85:15.

  The thickness of the UC layer can be appropriately determined according to the application to be used, but it is preferably 0.1 μm to 10 μm, more preferably 0.1 μm to 5 μm, and 0.1 μm to 1 μm. It is particularly preferable that the thickness is as follows. When the thickness is less than 0.1 μm, it is difficult to develop adhesiveness, and when the thickness exceeds 10 μm, difficulty is easily caused in the production process such as coating.

  The concentration of polyesterol and polyisocyanate in the UC composition can be adjusted using an appropriate solvent, and the concentration is preferably in the range of 0.5 to 80% by weight. More preferably, it is in the range of -70% by weight. If the concentration of the solution is too low, it will be difficult to form a coating film with the required film thickness, and an excessive amount of heat will be required during drying. If the concentration of the solution is too high, the solution viscosity becomes too high, which causes a problem that deteriorates operability during mixing and coating.

Examples of the solvent that can be used in the UC composition include, but are not limited to, toluene, MEK, cyclohexanone, solvesso, isophorone, xylene, MIBK, ethyl acetate, and butyl acetate.
In addition to the above components, the UC layer includes known curing accelerators, fillers, softeners, anti-aging agents, stabilizers, adhesion promoters, leveling agents, antifoaming agents, plasticizers, inorganic fillers, and tackifiers. Resins, fibers, colorants such as pigments, usable time extenders, and the like can also be used.

In order to form the UC layer and the gas barrier layer, the composition for forming each layer is formed on a plastic substrate by a roll coater method, a gravure method, a gravure offset method, a spray coating method, or a combination method thereof. Although it can apply | coat to desired thickness on a UC layer, it is not limited to these systems.
Moreover, after apply | coating to an unstretched film and drying, it can also be extended | stretched. For example, after drying, the film can be supplied to a tenter type stretching machine, and the film can be stretched simultaneously in the running direction and the width direction (simultaneous biaxial stretching) and heat-treated. Or after extending | stretching in the running direction of a film using a multistage heat roll etc., a coating material etc. may be apply | coated, and after extending | stretching, you may extend | stretch in the width direction (sequential biaxial stretching) with a tenter type stretching machine. It is also possible to combine running direction stretching and simultaneous biaxial stretching with a tenter.
The thickness of the gas barrier layer in the present invention is desirably at least 0.1 μm in order to sufficiently enhance the gas barrier property of the laminate.

[Gas barrier laminate]
The gas barrier laminate of the present invention is obtained by applying the above-described gas barrier coating onto a plastic substrate directly or via a UC layer and heat-treating it.
That is, after applying the gas barrier coating, heat treatment is performed once, thereby performing esterification reaction between the polyalcohol polymer (A) and the polycarboxylic acid polymer (B) and the polycarboxylic acid polymer (B). A gas barrier laminate is produced by ionic crosslinking with the compound (C) having a valent metal and a volatile base as constituent elements.

Since it can be influenced by the ratio of the polyalcohol-based polymer (A) and the polycarboxylic acid-based polymer (B), various components contained in the coating, etc., the preferable heat treatment conditions for the gas barrier coating are generally Although it cannot be said, it is preferably performed at a temperature of 100 ° C. or higher and 300 ° C. or lower, more preferably 120 ° C. or higher and 250 ° C. or lower, further preferably 140 ° C. or higher and 240 ° C. or lower, and particularly preferably 160 ° C. or higher and 220 ° C. or lower.
Specifically, heat treatment is performed for 90 seconds or more in a temperature range of 100 ° C. or more and less than 140 ° C., for 1 minute or more in a temperature range of 140 ° C. or more and less than 180 ° C., or for 30 seconds or more in a temperature range of 180 ° C. or more and less than 250 ° C. Preferably,
It is more preferable to perform heat treatment for 2 minutes or more in a temperature range of 100 ° C. or more and less than 140 ° C., 90 seconds or more in a temperature range of 140 ° C. or more and less than 180 ° C., or 1 minute or more in a temperature range of 180 ° C. or more and 240 ° C. or more. Preferably
It is particularly preferable to perform heat treatment for 4 minutes or more in a temperature range of 100 ° C. or more and less than 140 ° C., for 3 minutes or more in a temperature range of 140 ° C. or more and less than 180 ° C., or for about 2 minutes in a temperature range of 180 ° C. or more and less than 220 ° C. preferable.

As described in the Background Art section, after applying the paint, heating was performed to cause esterification reaction between the hydroxyl group in the polyalcohol-based polymer (A) and COOH in the polyacrylic acid-based polymer (B). However, when the gas barrier laminate was stored at high temperature and high humidity for a long time, the ester bond was hydrolyzed and the gas barrier property was significantly deteriorated.
On the other hand, when a paint further containing a compound (C) having a polyvalent metal and a volatile base as constituents is applied and heated, the compound (C) is decomposed to produce a polyvalent metal. The polyvalent metal is ionically crosslinked with the polycarboxylic acid-based polymer (B), so that even when exposed to high humidity, the gas barrier property can be suppressed and prevented from much lowering than before.

  EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to only these examples.

<Oxygen permeability>
The oxygen permeability at 25 ° C. and 80% RH was determined using an oxygen permeation tester OX-TRAN TWIN manufactured by Modern Control. Specifically, oxygen gas and nitrogen gas (carrier gas) humidified to 25 ° C. and 80% RH were used for oxygen permeability after exposure for 7 days in an initial state and an environment of 40 ° C. and 90% humidity. Sought each.

The oxygen permeability of the gas barrier layer formed from each property paint was determined by the following calculation formula.
1 / P _total = 1 / P _film + 1 / P _Ny
However,
P _total : Oxygen permeability of a laminated film composed of a gas barrier layer formed from each paint and a base film (biaxially stretched nylon film) layer. In the case of having a UC layer, the oxygen permeability of the gas barrier layer, the UC layer and the substrate film.
P _film : Oxygen permeability of a film layer (gas barrier layer) formed from each paint.
P _Ny : Oxygen permeability of the base film (biaxially stretched nylon film) layer. In the case of having a UC layer, oxygen permeability of the UC layer and the substrate film.

<Water resistance>
The appearance change of the gas barrier laminate was observed when the gas barrier laminate obtained by laminating the gas barrier paint on the plastic substrate was boiled in distilled water at 95 ° C. for 30 minutes.

[Production Example 1]
100 parts by weight of PVA (manufactured by Kuraray Co., Ltd., Poval 105 (polyvinyl saponification degree 98 to 99%, average polymerization degree about 500)) is added to 900 parts by weight of distilled water and heated at 95 ° C. for 3 hours to dissolve PVA. A PVA solution having a solid content of 10% was obtained.

[Production Example 2]
100 parts by weight of EMA (weight average molecular weight 100000) was added to 900 parts by weight of distilled water and heated at 95 ° C. for 3 hours to dissolve EMA to obtain an EMA solution having a solid content of 10%.

[Production Example 3]
400 parts by weight of polyacrylic acid (number average molecular weight 200000, 25% by weight aqueous solution, trade name A10H manufactured by Toagosei Co., Ltd.) is added to 600 parts by weight of distilled water and heated for 1 hour to dissolve the polyacrylic acid. A 10% polyacrylic acid solution was obtained.

[Production Example 4]
10 parts by weight of zinc oxide, 80 parts by weight of 25% aqueous ammonia and 10 parts by weight of ammonium hydrogen carbonate were mixed to obtain a transparent zinc compound solution.

[Example 1]
40 g of the PVA solution of Production Example 1 and 60 g of the EMA solution of Production Example 2 are mixed in a glass container, and 38.8 g of the zinc compound solution of Production Example 4 is added and mixed. Further, 3.8 g of a 10% aqueous sodium hydroxide solution is added. In addition, a gas barrier paint having a solid content of 10%, zinc being 1 chemical equivalent to carboxylic acid, and sodium hydroxide being neutralized by 10 mol% with respect to carboxylic acid was obtained.
This gas barrier coating was applied on a biaxially stretched nylon film (thickness 15 μm) on a bar coater No. 12 and dried in an electric oven at 80 ° C. for 2 minutes and then heated in an electric oven at 180 ° C. for 2 minutes to obtain a gas barrier laminate having a thickness of 1.5 μm.
The obtained gas barrier laminate was measured for oxygen permeability before and after being left in an environment of 40 ° C. and 90% humidity for 7 days. Moreover, water resistance was evaluated about the obtained gas-barrier laminated body. The results are shown in Table 2.

[Examples 2 to 5]
A gas barrier laminate was obtained in the same manner as in Example 1 except that the amount of the polyvalent metal compound used in Example 1 and the amount of sodium hydroxide were changed as shown in Table 1 to obtain water resistance and high temperature and high humidity. The oxygen permeability before and after storage was measured. The results are shown in Table 2.

[Example 6]
In a glass container, 40 g of the PVA solution of Production Example 1 and 60 g of the EMA solution of Production Example 2 were added and mixed, and then 38.8 g of the zinc compound solution of Production Example 4 was added and mixed. Further, 3.8 g of 10% aqueous sodium hydroxide solution After mixing, 6.5 g of 25% aqueous ammonia is added and mixed. A gas barrier in which solid content is 10%, zinc is 1 chemical equivalent to carboxylic acid, and sodium hydroxide is 10 mol% neutralized to carboxylic acid. A paint was obtained.
This gas barrier coating was applied on a biaxially stretched nylon film (thickness 15 μm) on a bar coater No. 12 and dried in an electric oven at 80 ° C. for 2 minutes, and then heated in an electric oven at 180 ° C. for 2 minutes to obtain a gas barrier laminate having a thickness of 1.5 μm.
In the same manner as in Example 1, the water resistance of the gas barrier laminate and the oxygen permeability before and after storage under high temperature and high humidity were measured. The results are shown in Table 2.

[Example 7]
A gas barrier laminate was obtained in the same manner as in Example 6 except that 5.8 g of ethanolamine shown in Table 1 was used instead of 25% aqueous ammonia used in Example 6, and water resistance and oxygen permeability were measured. did. The results are shown in Table 2.

[Example 8]
In a glass container, 40 g of the PVA solution of Production Example 1 and 60 g of the EMA solution of Production Example 2 were added and mixed, and 3.8 g of 10% sodium hydroxide was added and mixed. Further, 31.2 g of 25% aqueous ammonia and 3.9 g of ammonium hydrogen carbonate were added and stirred well. Then, 3.9 g of zinc oxide was added and mixed. The solid content was 10% and zinc was one chemical equivalent to the carboxylic acid. Sodium obtained a gas barrier paint having a neutralization amount of 10 mol% with respect to the carboxylic acid.
Thereafter, a gas barrier laminate was obtained in the same manner as in Example 1, and the water resistance and oxygen permeability before and after storage under high temperature and high humidity were measured. The results are shown in Table 2.

[Comparative Example 1]
Add 40g of PVA solution of Production Example 1 and 60g of EMA solution of Production Example 2 to a glass container, mix, add 3.8g of 10% sodium hydroxide aqueous solution, mix, 10% solids, sodium hydroxide into carboxylic acid On the other hand, a gas barrier coating was obtained with a neutralization amount of 10 mol%.
Thereafter, a gas barrier laminate was obtained in the same manner as in Example 1, and the water resistance and oxygen permeability before and after storage under high temperature and high humidity were measured. The results are shown in Table 2.

[Comparative Example 2]
In a glass container, 40 g of the PVA solution of Production Example 1 and 60 g of the EMA solution of Production Example 2 were added and mixed, and then 38.8 g of the zinc compound solution of Production Example 4 was added and mixed. The solid content was 10% and zinc was added to the carboxylic acid. A gas barrier paint having a chemical equivalent of 1 was obtained.
Thereafter, a gas barrier laminate was obtained in the same manner as in Example 1, and the water resistance and oxygen permeability before and after storage under high temperature and high humidity were measured. The results are shown in Table 2.

[Comparative Example 3]
In a glass container, 40 g of the PVA solution of Production Example 1 and 60 g of the EMA solution of Production Example 2 were added and mixed, and 3.8 g of 10% sodium hydroxide was added and mixed. When 3.9 g of zinc oxide was added to this mixture, it immediately aggregated and gelled.

[Comparative Example 4]
100 g of the polyacrylic acid solution of Production Example 3, 218 g of 25% aqueous ammonia, and 27 g of ammonium hydrogen carbonate were mixed well, then 27.2 g of zinc oxide was added and mixed to obtain a solid content of 10%, and zinc was 4. A gas barrier paint having 8 chemical equivalents was obtained.
Thereafter, a gas barrier laminate was obtained in the same manner as in Example 1, and the water resistance and oxygen permeability before and after storage under high temperature and high humidity were measured. The results are shown in Table 2.

[Comparative Example 5]
Table 2 shows the results obtained by applying a top coat to the gas barrier laminate obtained in Comparative Example 4 and measuring the water resistance test and oxygen permeability.
The top coat was obtained by mixing 40 g of an epoxy resin (ARP-01 manufactured by Resinas Kasei Co., Ltd.), 10 g of a curing agent (modified aliphatic polyamine), and 50 g of a diluent 2-butanone. This top coat forming paint was applied to bar coater no. Coating was carried out at 20 and heat treatment was carried out at 50 ° C. for 24 hours to form a top coat.

Claims (8)

A gas barrier comprising a polyalcohol-based polymer (A), a polycarboxylic acid-based polymer (B), a compound (C) comprising a polyvalent metal and a volatile base, and an alkali metal compound (D) Paint. The gas barrier paint according to claim 1, wherein the compound (C) comprising a polyvalent metal and a volatile base comprises NH ₃ as a constituent element. The gas barrier coating composition according to claim 1 or 2, wherein the polyalcohol-based polymer (A) is any one of polyvinyl alcohol, ethylene-vinyl alcohol copolymer, saccharide, or a mixture thereof. The gas barrier paint according to any one of claims 1 to 3, wherein the polycarboxylic acid polymer (B) is an olefin-maleic acid copolymer. The gas barrier coating composition according to claim 4, wherein the olefin-maleic acid copolymer is an ethylene-maleic acid copolymer. The gas barrier paint according to any one of claims 1 to 5, wherein the polyvalent metal is zinc. 7. The gas barrier coating composition according to claim 1, wherein the alkali metal compound (D) is an alkali metal hydroxide. A gas barrier layer formed from the gas barrier paint according to any one of claims 1 to 7 is laminated directly on a plastic substrate or on a plastic substrate via an undercoat layer. Gas barrier laminate.