JP7506370B2 - Resin composition - Google Patents

Description

The present invention relates to a resin composition.

Packaging materials used for packaging foods and other products are required to have functions such as protecting the contents, retort resistance, heat resistance, transparency, and processability. Gas barrier properties are particularly important for maintaining the quality of the contents. Recently, high gas barrier properties are being required not only for packaging materials, but also for materials used in electronic materials such as solar cells and semiconductors.

Patent Document 1 describes that by combining a resin having a hydroxyl group and an isocyanate compound with a plate-like inorganic compound such as a clay mineral and a light-blocking agent, properties such as gas barrier properties are improved.

Furthermore, Patent Document 2 describes a material whose main component is denatured clay, and claims that by using denatured clay, and if necessary, additives, to orient and densely stack the denatured clay crystals, a membrane material can be obtained that has the mechanical strength, gas barrier properties, water resistance, thermal stability and flexibility to be used as a free-standing membrane.

International Publication No. 2013/027609 JP 2007-277078 A

Resin compositions used in applications such as coating agents, adhesives, and gas barrier materials desirably have high gas barrier properties and a thixotropy index (TI value) suitable for coating. The better the TI value, the easier the paint will be to apply and the less likely it will drip during the coating process, and the more uniform the coated surface will be.

The object of the present invention is to provide a resin composition which has a good thixotropy index and excellent oxygen barrier properties and water vapor barrier properties.

The inventors discovered that by combining a dioctahedral smectite containing at least one interlayer ion selected from the group consisting of ammonium ions, lithium ions, and hydrogen ions, with a predetermined amount of silica and a vinyl resin having hydroxyl groups, it is possible to obtain a good thixotropy index and excellent oxygen barrier properties and water vapor barrier properties, and thus completed the present invention.

That is, in one aspect, the present invention provides a resin composition containing dioctahedral smectite, silica, and a vinyl resin having a hydroxyl group, in which the dioctahedral smectite contains at least one interlayer ion selected from the group consisting of ammonium ions, lithium ions, and hydrogen ions, and the silica content is 4 to 25 mass% based on the total amount of the dioctahedral smectite and silica.

The resin composition may further contain a solvent. In the resin composition, the solvent may contain alcohol, and the alcohol content may be 20 to 80 mass% based on the total amount of the solvent.

The dioctahedral smectite may be montmorillonite. The sodium ion equivalent of the dioctahedral smectite may be less than 10 meq/100 g. The sum of the ammonium ion equivalent, lithium ion equivalent, and hydrogen ion equivalent of the dioctahedral smectite may be 50 to 120 meq/100 g.

The resin composition may further contain a polycarboxylic acid. The hydroxyl value of the vinyl resin having hydroxyl groups may be 800 to 1,500.

According to the present invention, it is possible to provide a resin composition which has a good thixotropy index and is excellent in oxygen barrier property and water vapor barrier property.

Hereinafter, the embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In this specification, the upper and lower limit values described individually can be combined in any combination.

In one embodiment, the resin composition contains dioctahedral smectite, silica, and a vinyl resin having a hydroxyl group, in which the dioctahedral smectite contains at least one interlayer ion selected from the group consisting of ammonium ions, lithium ions, and hydrogen ions, and the silica content is 4 to 25 mass% based on the total amount of the dioctahedral smectite and silica.

<Dioctahedral smectite>
The basic structure of clay minerals is composed of Si-O tetrahedral sheets and Al-O octahedral sheets, and is called dioctahedral when the cations that enter the octahedral sheets are trivalent ions such as Al3 ⁺ . The cation exchange capacity of dioctahedral smectite is usually 60 to 150 meq/100 g. Montmorillonite and beidellite are known as specific structures of dioctahedral smectite.

The dioctahedral smectite in the embodiment is a dioctahedral smectite containing at least one interlayer ion selected from the group consisting of ammonium ions, lithium ions, and hydrogen ions.

The sodium ion equivalent of the dioctahedral smectite may be less than 10 meq/100 g. The sodium ion equivalent of the dioctahedral smectite may be, for example, 5 meq/100 g or less, or 2 meq/100 g or less. The sodium ion equivalent of the dioctahedral smectite can be measured by ion chromatography using the amount of cations eluted in a 1 N ammonium acetate solution.

The total of the ammonium ion equivalent, lithium ion equivalent, and hydrogen ion equivalent of the dioctahedral smectite may be 50 to 120 meq/100g. The total of the ammonium ion equivalent, lithium ion equivalent, and hydrogen ion equivalent of the dioctahedral smectite may be 50 meq/100g or more, 80 meq/100g or more, or 100 meq/100g or more, and may be 120 meq/100g or less, or 110 meq/100g or less. The ammonium ion equivalent of the dioctahedral smectite can be determined by measuring the amount of cations dissolved in a 1N potassium chloride solution, and the lithium ion equivalent can be determined by measuring the amount of cations dissolved in a 1N ammonium acetate solution, respectively, by ion chromatography. The hydrogen ion equivalent can be determined from the difference between the amount of cations before ion exchange and the amount of cations after ion exchange. For example, when using montmorillonite in which the interlayer ion is sodium, the amount of sodium ions eluted from the montmorillonite into a 1N ammonium acetate solution before and after the ion exchange operation can be measured by ion chromatography, and the hydrogen ion equivalent can be calculated from the difference.

The method for exchanging the interlayer ions (cations) of the dioctahedral smectite with at least one selected from the group consisting of ammonium ions, lithium ions, and hydrogen ions may be a conventional ion exchange method, for example, a method in which an aqueous dispersion of dioctahedral smectite is treated with a cation exchange resin that has hydrogen ions, ammonium ions, or lithium ions previously retained therein. The method may be a method in which the aqueous dispersion is passed through a column packed with an ion exchange resin, or a method in which the ion exchange resin and the aqueous dispersion are mixed and batch stirred.

To explain this with a more specific example, for example, when exchanging the interlayer cations with lithium ions, Amberlite IR120B-H is treated in advance with lithium hydroxide to cause the ion exchange resin to retain the lithium ions. An aqueous dispersion with a concentration of dioctahedral smectite of 2% is passed through a column packed with the ion exchange resin retaining the lithium ions at a rate of 1 mL/min. After passing the aqueous dispersion through the column, it is dried overnight in an oven at 110°C to obtain dioctahedral smectite with lithium ions as the interlayer ions.

The content of the dioctahedral smectite may be, for example, 5% by mass or more, 20% by mass or more, 30% by mass or more, or 40% by mass or more, based on the total amount of nonvolatile content in the resin composition, from the viewpoint of, for example, being more excellent in water vapor barrier property and oxygen barrier property (for example, oxygen barrier property under high humidity), and may be, for example, 70% by mass or less, or 60% by mass or less, based on the viewpoint of, for example, being more excellent in moldability of the resin composition and improving adhesion to the substrate. The content of the dioctahedral smectite may be, for example, 5 to 70% by mass, 20 to 60% by mass, or 40 to 60% by mass, based on the total amount of nonvolatile content in the resin composition. Nonvolatile content means components other than the solvent in the resin composition.

<Vinyl resin having hydroxyl group>
The resin composition contains a vinyl resin having a hydroxyl group. The vinyl resin having a hydroxyl group can be obtained, for example, by polymerizing an ester of an alcohol having a polymerizable double bond, followed by a saponification treatment.

The ester of the alcohol having a polymerizable double bond may be, for example, a vinyl ester. Examples of the vinyl ester include vinyl acetate, vinyl chloroacetate, vinyl propionate, vinyl butyrate, vinyl methoxyacetate, and vinyl benzoate.

A vinyl resin having a hydroxyl group can be obtained, for example, by polymerization or copolymerization of a vinyl monomer having a hydroxyl group, or by copolymerization of a vinyl monomer having a hydroxyl group and a vinyl monomer not having a hydroxyl group. A vinyl monomer having a hydroxyl group is a monomer having at least one group having a polymerizable double bond (for example, a vinyl group, a (meth)allyl group, or a (meth)acryloyl group) and at least one hydroxyl group. A vinyl monomer not having a hydroxyl group is a monomer having at least one group having a polymerizable double bond (for example, a vinyl group, a (meth)allyl group, or a (meth)acryloyl group) and not having a hydroxyl group. A (meth)allyl group means an allyl group or a methallyl group. A (meth)acryloyl group means an acryloyl group or a methacryloyl group.

Examples of vinyl monomers having a hydroxyl group (hydroxyl group-containing vinyl monomers) include (meth)allyl alcohol, vinyl alcohol; alkene monools or alkene diols having 4 to 12 carbon atoms, such as 1-buten-3-ol; alkenyl ethers having a polymerizable double bond at the end, such as 2-hydroxyethylpropenyl ether; hydroxystyrene; hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate; and monoesters of compounds obtained by ring-opening polymerization of ε-caprolactone and (meth)acrylic acid.

Examples of vinyl monomers that do not have a hydroxyl group (hydroxyl group-free vinyl monomers) include olefins such as ethylene, propylene, isobutylene, butadiene, and isoprene; halogenated olefins such as dichloroethylene and vinyl chloride; (meth)acrylic acid; (meth)acrylic acid esters; vinyl esters; maleic acid diesters; fumaric acid diesters; itaconic acid diesters; (meth)acrylamide; styrene and its derivatives; vinyl ethers; vinyl ketones; maleimides; allyl compounds; (meth)acrylonitrile; compounds having a heterocyclic group substituted with a vinyl group, such as vinylpyridine, N-vinylpyrrolidone, vinylcarbazole, N-vinylimidazole, and vinylcaprolactone; and vinyl amides such as N-vinylformamide and N-vinylacetamide.

Examples of (meth)acrylic acid esters include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, amyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, t-octyl (meth)acrylate, dodecyl (meth)acrylate, octadecyl (meth)acrylate, and acetone. (meth)acrylate, phenyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-(2-methoxyethoxy)ethyl (meth)acrylate, 3-phenoxy-2-hydroxypropyl (meth)acrylate, 2-chloroethyl (meth)acrylate, glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, Vinyl acrylate, 2-phenylvinyl (meth)acrylate, 1-propenyl (meth)acrylate, allyl (meth)acrylate, 2-allyloxyethyl (meth)acrylate, propargyl (meth)acrylate, benzyl (meth)acrylate, diethylene glycol monomethyl ether (meth)acrylate, diethylene glycol monoethyl ether (meth)acrylate, triethylene glycol monomethyl ether (meth)acrylate, triethylene glycol monoethyl ether (meth)acrylate, polyethylene glycol monomethyl ether (meth)acrylate, (meth)acrylic acid Examples of the acrylates include polyethylene glycol monoethyl ether, β-phenoxyethoxyethyl (meth)acrylate, nonylphenoxy polyethylene glycol (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, trifluoroethyl (meth)acrylate, octafluoropentyl (meth)acrylate, perfluorooctylethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, tribromophenyl (meth)acrylate, tribromophenyloxyethyl (meth)acrylate, and γ-butyrolactone (meth)acrylate.

Examples of vinyl esters include the monomers listed above.

Examples of maleic acid diesters include dimethyl maleate, diethyl maleate, and dibutyl maleate.

Examples of fumaric acid diesters include dimethyl fumarate, diethyl fumarate, and dibutyl fumarate.

Examples of itaconate diesters include dimethyl itaconate, diethyl itaconate, and dibutyl itaconate.

Examples of (meth)acrylamides include (meth)acrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-n-butylacryl(meth)amide, N-t-butyl(meth)acrylamide, N-cyclohexyl(meth)acrylamide, N-(2-methoxyethyl)(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-phenyl(meth)acrylamide, N-nitrophenylacrylamide, N-ethyl-N-phenylacrylamide, N-benzyl(meth)acrylamide, (meth)acryloylmorpholine, diacetone acrylamide, N-methylol acrylamide, N-hydroxyethyl acrylamide, vinyl(meth)acrylamide, N,N-diallyl(meth)acrylamide, and N-allyl(meth)acrylamide.

Examples of styrene derivatives include methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, isopropylstyrene, butylstyrene, hydroxystyrene, methoxystyrene, butoxystyrene, acetoxystyrene, chlorostyrene, dichlorostyrene, bromostyrene, chloromethylstyrene, α-methylstyrene, etc.

Examples of vinyl ethers include methyl vinyl ether, ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, octyl vinyl ether, methoxyethyl vinyl ether, phenyl vinyl ether, etc.

Examples of vinyl ketones include methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, phenyl vinyl ketone, etc.

Examples of maleimides include maleimide, butylmaleimide, cyclohexylmaleimide, phenylmaleimide, etc.

Examples of allyl compounds include allyl acetate, allyl alcohol, allylamine, N-allylaniline, allyl chloride, allyl bromide, etc.

The vinyl resin having hydroxyl groups may contain hydroxyl groups so that the hydroxyl value (unit: mgKOH/g) is, for example, in the range of 800 to 1500. The hydroxyl value of the vinyl resin having hydroxyl groups may be, for example, 800 or more, 900 or more, 950 or more, or 1000 or more, and may be 1500 or less, 1400 or less, or 1300 or less. The hydroxyl value of the vinyl resin having hydroxyl groups may be, for example, 800 to 1500, 900 to 1400, 950 to 1300, or 1000 to 1300. The hydroxyl value can be measured by the hydroxyl value measurement method described in JIS-K0070. In addition, when the vinyl resin is synthesized and used, it is also possible to calculate the hydroxyl value from the monomer composition used.

When the vinyl resin having a hydroxyl group is a resin obtained by saponifying a polymer of an ester of an alcohol having a polymerizable double bond, the weight average molecular weight of the vinyl resin having a hydroxyl group can be calculated from the weight average molecular weight of the vinyl resin before saponification. The weight average molecular weight of the vinyl resin before saponification (vinyl resin having an acetoxy group (CH ₃ C(═O)O—)) measured by GPC (gel permeation chromatography) in terms of polystyrene is not particularly limited, but may be 300 or more and 4,000 or less.

The vinyl resin having a hydroxyl group is preferably a vinyl resin having a structural unit A (also referred to as partial structure A) represented by the following formula (1) (hereinafter also referred to as "vinyl resin A"). In this case, since vinyl resin A has a hydroxyl group, not only does the cohesive force of the vinyl resin improve due to the interaction between the hydroxyl groups, but the affinity with the dioctahedral smectite is also increased, and therefore, even higher gas barrier properties are exhibited. In addition, since vinyl resin A has the structural unit (A), not only does it improve the solubility in alcohol, but it can also impart water resistance to the resin composition, so that further improvements in water vapor barrier properties and oxygen barrier properties under high humidity can be expected.

In formula (1), m represents 0 or 1, and * represents a bond. m is preferably 0.

When the vinyl resin having hydroxyl groups contains the structural unit A, the content of the structural unit A is preferably 85 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and preferably 99 mol% or less, based on the total molar amount of hydroxyl groups in the vinyl resin having hydroxyl groups. The content of the structural unit A is preferably 85 mol% or more and 99 mol% or less, more preferably 90 mol% or more and 99 mol% or less, based on the total molar amount of hydroxyl groups in the vinyl resin having hydroxyl groups. It is preferable that the content of the structural unit A in which m is 0 is in the above range.

The vinyl resin having a hydroxyl group may contain a structural unit (another structural unit) other than the structural unit A. The other structural unit may be, for example, a structural unit B (also referred to as a partial structure B) represented by the following formula (2). The vinyl resin having a hydroxyl group preferably contains the structural unit A and further contains the structural unit B. In one embodiment, the vinyl resin having a hydroxyl group may be composed only of the structural unit A and the structural unit B. By containing the structural unit B in the vinyl resin having a hydroxyl group, the film formability, film strength, and adhesiveness of the resin composition when formed into a molded product are further improved.

In formula (2), ^R1 represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, n represents 0 or 1, and * represents a bond. Specifically, ^R1 is a hydrogen atom, a methyl group, or an ethyl group, and n is preferably 0. ^R2 is a hydrogen atom or an acetyl group. Here, ^R1 and ^R2 are not simultaneously hydrogen atoms.

The content of the structural unit B is 1 mol% or more with respect to the total molar amount of hydroxyl groups in the vinyl resin having hydroxyl groups, from the viewpoint of excellent water resistance. The content of the structural unit B is preferably 30 mol% or less, more preferably 15 mol% or less, and even more preferably 10 mol% or less with respect to the total molar amount of hydroxyl groups in the vinyl resin having hydroxyl groups, from the viewpoint of excellent film formability, film strength, adhesiveness of the composition when formed into a molded body. The content of the structural unit B is preferably 1 mol% or more and 30 mol% or less, more preferably 1 mol% or more and 15 mol% or less, and even more preferably 1 mol% or more and 10 mol% or less with respect to the total molar amount of hydroxyl groups in the vinyl resin having hydroxyl groups. It is preferable that the content of the structural unit B in which R ¹ is a hydrogen atom, R ² is an acetyl group, and n is 0 is in the above range.

When the vinyl resin having a hydroxyl group contains structural units A and B, the mole percentage of the content of structural unit A relative to the total content of structural unit A and structural unit B (A/(A+B)×100) is preferably 85 mol% or more, or 99 mol% or less, from the viewpoint of further improving the gas barrier properties.

There are no particular limitations on the method for producing the vinyl resin having the structural unit A and/or the structural unit B, and it can be produced by a known, commonly used method. For example, a vinyl resin having a hydroxyl group can be produced by polymerizing an ester of a hydroxyl group-containing vinyl monomer corresponding to the structural unit A or B, followed by a saponification treatment.

Examples of hydroxyl-containing vinyl monomers corresponding to structural unit A include vinyl alcohol, allyl alcohol, and crotyl alcohol. The ester in the ester of the hydroxyl-containing vinyl monomer corresponding to structural unit B may be an ester as exemplified above. Among the esters of the hydroxyl-containing vinyl monomer corresponding to structural unit B, preferred are acetate esters such as vinyl acetate, allyl acetate, and crotyl acetate. These may be used alone or in combination of two or more.

Examples of hydroxyl-containing vinyl monomers corresponding to structural unit B include isopropenyl alcohol, methallyl alcohol, and isobutenyl alcohol. Examples of esters in the esterification products of hydroxyl-containing vinyl monomers corresponding to structural unit A include acetates, propanoates, butanoates, 2-methylpropanoates, pentanoates, 3-methylbutanoates, 2,2-dimethylpropanoates, hexanoates, cyclohexylcarboxylates, and benzoates. Among the esterification products of hydroxyl-containing vinyl monomers corresponding to structural unit A, the acetates isopropenyl acetate, methallyl acetate, and isobutenyl acetate are preferred. These may be used alone or in combination of two or more.

The vinyl resin having a hydroxyl group may be a homopolymer obtained by polymerizing a single monomer, or a copolymer obtained by copolymerizing multiple types of monomers. In this case, the vinyl monomer may be a combination of monomers having a vinyl group, a (meth)allyl group, or a (meth)acryloyl group.

Vinyl resins having hydroxyl groups can be obtained by polymerizing vinyl monomers by radical polymerization, anionic polymerization, cationic polymerization, etc. A polymerization initiator may be used during polymerization. Examples of polymerization initiators include thermal radical polymerization initiators, photoradical polymerization initiators, anionic polymerization initiators, and cationic polymerization initiators.

Examples of thermal radical polymerization initiators include peroxides such as t-butyl peroxybenzoate, di-t-butyl peroxide, cumene perhydroxide, acetyl peroxide, benzoyl peroxide, and lauroyl peroxide; and azo compounds such as azobisisobutylnitrile, azobis-2,4-dimethylvaleronitrile, and azobiscyclohexanecarbonitrile.

Examples of photoradical polymerization initiators include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl propan-1-one, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, and 2,4,6-trimethylbenzoyl-diphenyl phosphine oxide.

Examples of anionic polymerization initiators include organic alkali metals such as methyllithium, n-butyllithium, sec-butyllithium, and t-butyllithium; organic alkaline earth metals such as methylmagnesium chloride and methylmagnesium bromide; and alkali metals such as lithium, sodium, and potassium.

Examples of cationic polymerization initiators include protonic acids such as hydrochloric acid, sulfuric acid, perchloric acid, trifluoroacetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, chlorosulfonic acid, and fluorosulfonic acid; Lewis acids such as boron trifluoride, aluminum chloride, titanium tetrachloride, stannic chloride, and ferric chloride.

In an embodiment, one type of vinyl resin may be used alone, or multiple vinyl resins may be used in combination. The vinyl resin may be a linear polymer or a branched polymer. If the vinyl resin is a branched polymer, it may be a comb type or a star type.

The content of the vinyl resin having a hydroxyl group may be 30% by mass or more, or 40% by mass or more, based on the total amount of non-volatile matter in the resin composition, from the viewpoint of obtaining even better water vapor barrier properties and oxygen barrier properties, and may be 95% by mass or less, 80% by mass or less, 70% by mass or less, or 60% by mass or less, based on the viewpoint of obtaining even better moldability of the resin composition.

<Silica>
The resin composition further contains silica. In this specification, "silica" means silicon dioxide (SiO ₂ ). Silica may be crystalline silica or amorphous silica. Silica may be contained in natural minerals or may be added to dioctahedral smectite later. Crystalline silica refers to a solid substance having a crystal structure (atoms, ions or molecules constituting a crystal are arranged with three-dimensional periodicity to form a spatial lattice). Amorphous silica refers to a solid state substance in which atoms (or molecules) are assembled without forming crystals with a regular spatial arrangement.

The silica content is 4 to 25% by mass based on the total amount of dioctahedral smectite and silica. From the viewpoint of obtaining a better thixotropy index, the silica content may be 4% by mass or more, 10% by mass or more, or 15% by mass or more based on the total amount of dioctahedral smectite and silica, and from the viewpoint of obtaining even better oxygen barrier properties and water vapor barrier properties, the silica content may be 25% by mass or less, or 20% by mass or less based on the total amount of dioctahedral smectite and silica.

The total content of dioctahedral smectite and silica may be, for example, 5% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more, 35% by mass or more, or 40% by mass or more, and may be 70% by mass or less, or 60% by mass or less, based on the total amount of non-volatile matter in the resin composition.

<Solvent>
The resin composition may further contain a solvent depending on the intended use. Examples of the solvent include organic solvents. Examples of the solvent include alcohol, water, methyl ethyl ketone, acetone, ethyl acetate, butyl acetate, toluene, dimethylformamide, acetonitrile, methyl isobutyl ketone, cyclohexanone, methyl cellosolve, ethyl diglycol acetate, and propylene glycol monomethyl ether acetate. The type and amount of the solvent may be appropriately selected depending on the intended use.

From the viewpoint of achieving even better drying properties of the coating film, it is preferable that the solvent contains alcohol. The solvent may contain only alcohol. Examples of alcohol include methanol, ethanol, 1-propanol, 2-propanol, and methoxypropanol (1-methoxy-2-propanol, etc.). The alcohol may be contained alone or in combination of two or more kinds.

When the resin composition contains alcohol as a solvent, the alcohol content may be 20% by mass or more, 25% by mass or more, 30% by mass or more, 35% by mass or more, 40% by mass or more, or 45% by mass or more, based on the total amount of solvent, and may be 80% by mass or less, 75% by mass or less, 70% by mass or less, 65% by mass or less, 60% by mass or less, 55% by mass or less, or 50% by mass or less, based on the total amount of solvent. When the resin composition contains alcohol as a solvent, the alcohol content may be 20 to 80% by mass, 25 to 70% by mass, 30 to 60% by mass, or 40 to 50% by mass, based on the total amount of solvent.

The alcohol may contain ethanol from the viewpoint of more excellent drying properties (blocking properties). The alcohol may contain only ethanol, or may contain ethanol and alcohol other than ethanol. The alcohol other than ethanol may be, for example, at least one selected from the group consisting of methanol, 1-propanol, 2-propanol, and methoxypropanol. The content of ethanol in the alcohol may be 50% by mass or more, 80% by mass or more, or 95% by mass or more, or may be 100% by mass, based on the total amount of alcohol.

The content of non-volatile matter in the resin composition may be 1 to 10 mass %, preferably 2 to 8 mass %, and more preferably 4 to 7 mass %, based on the total amount of the resin composition.

<Polycarboxylic acid>
The resin composition may further contain a polycarboxylic acid. In this specification, the polycarboxylic acid means a compound having two or more carboxyl groups. As the polycarboxylic acid, a resin having two or more carboxyl groups (excluding vinyl resins having hydroxyl groups and carboxyl groups) can be used. As the polycarboxylic acid, for example, polyacrylic acid, polymaleic acid, polyaspartic acid, or a copolymer of polyacrylic acid and polymaleic acid can be mentioned.

The content of polycarboxylic acid may be 5% by mass or more, 10% by mass or more, or 15% by mass or more, and 30% by mass or less, 25% by mass or less, or 20% by mass or less, based on the total content of vinyl resin having hydroxyl groups and polycarboxylic acid. When the resin composition contains a resin (other resin) other than vinyl resin having hydroxyl groups and polycarboxylic acid, the content of polycarboxylic acid may be within the above range relative to the total content of vinyl resin having hydroxyl groups, polycarboxylic acid, and other resin.

<Other Ingredients>
The resin composition may further contain a modifying agent. Examples of the modifying agent include a coupling agent, a silane compound, and an acid anhydride. When the resin composition contains these modifying agents, the wettability of the dioctahedral smectite is improved, and the dispersibility in the resin composition is further improved. The modifying agent may be used alone or in combination of two or more types.

Examples of coupling agents include silane coupling agents, titanium coupling agents, zirconium coupling agents, aluminum coupling agents, etc.

Examples of silane coupling agents include epoxy group-containing silane coupling agents, amino group-containing silane coupling agents, (meth)acrylic group-containing silane coupling agents, and isocyanate group-containing silane coupling agents. Examples of epoxy group-containing silane coupling agents include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Examples of amino group-containing silane coupling agents include 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, and N-phenyl-γ-aminopropyltrimethoxysilane. Examples of the (meth)acrylic group-containing silane coupling agent include 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, etc. Examples of the isocyanate group-containing silane coupling agent include 3-isocyanatepropyltriethoxysilane, etc.

Examples of titanium coupling agents include isopropyl triisostearoyl titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl isostearoyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tris(dioctyl pyrophosphate) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate, bis(dioctyl pyrophosphate)oxyacetate titanate, and bis(dioctyl pyrophosphate)ethylene titanate.

Examples of zirconium coupling agents include zirconium acetate, ammonium zirconium carbonate, zirconium fluoride, etc.

Examples of aluminum coupling agents include acetoalkoxyaluminum diisopropylate, aluminum diisopropoxymonoethyl acetoacetate, aluminum trisethyl acetoacetate, aluminum trisacetylacetonate, etc.

Examples of silane compounds include alkoxysilanes, silazanes, and siloxanes. Examples of alkoxysilanes include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, 1,6-bis(trimethoxysilyl)hexane, and trifluoropropyltrimethoxysilane. Examples of silazanes include hexamethyldisilazane. Examples of siloxanes include hydrolyzable group-containing siloxanes.

Examples of acid anhydrides include succinic anhydride, maleic anhydride, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, alkenyl succinic anhydride, etc.

The content of the modifier is preferably 0.1 to 30% by mass based on the total amount of dioctahedral smectite. If the content of the modifier is 0.1% by mass or more, the dispersibility of the dioctahedral smectite in the resin composition is better. Furthermore, if the content of the modifier is 30% by mass or less, the effect of the modifier on the mechanical properties of the resin composition can be further suppressed. The content of the modifier is preferably 0.3 to 20% by mass, and more preferably 0.5 to 15% by mass.

The resin composition may contain various additives (excluding compounds corresponding to vinyl resins having hydroxyl groups, dioctahedral smectite, silica, modifiers, and solvents). Examples of additives include organic fillers, inorganic fillers, stabilizers (antioxidants, heat stabilizers, UV absorbers, etc.), plasticizers, antistatic agents, lubricants, antiblocking agents, colorants, crystal nucleating agents, oxygen scavengers (compounds having oxygen scavenging function), tackifiers, etc. These various additives may be used alone or in combination of two or more.

Among the additives, inorganic fillers include inorganic substances such as metals, metal oxides, resins, and minerals, as well as composites of these. Specific examples of inorganic fillers include alumina, titanium, zirconia, copper, iron, silver, mica, talc, aluminum flakes, glass flakes, clay minerals, and the like. Among these, clay minerals may be used in combination for the purpose of improving gas barrier properties.

Examples of compounds that have oxygen scavenging function include low molecular weight organic compounds that react with oxygen, such as hindered phenol compounds, vitamin C, vitamin E, organic phosphorus compounds, gallic acid, and pyrogallol, as well as transition metal compounds such as cobalt, manganese, nickel, iron, and copper.

Examples of tackifiers include xylene resin, terpene resin, phenol resin, and rosin resin. Adding a tackifier can improve adhesion to various film materials immediately after application. The amount of tackifier added is preferably 0.01 to 5 parts by mass per 100 parts by mass of the total resin composition.

<Molded body>
The molded body of the embodiment can be obtained by molding the above-mentioned resin composition. The molded body may be made of a resin composition or may be made of a cured product of the resin composition. The molding method is optional and may be selected appropriately depending on the application. There is no limitation on the shape of the molded body, and it may be a plate, sheet, or film, may have a three-dimensional shape, may be applied to a substrate, or may be molded in a form that exists between the substrate and the substrate.

When producing a plate- or sheet-shaped molded product, examples of the methods include molding the resin composition using extrusion molding, flat press, profile extrusion molding, blow molding, compression molding, vacuum molding, injection molding, etc. When producing a film-shaped molded product, examples of the methods include melt extrusion, solution casting, inflation film molding, cast molding, extrusion lamination molding, calendar molding, sheet molding, fiber molding, blow molding, injection molding, rotational molding, and coating molding. When the resin composition is cured by heat or active energy rays, the resin composition may be molded using various curing methods using heat or active energy rays.

When the resin composition is in a liquid state, it may be molded by coating. Coating methods include spraying, spin coating, dipping, roll coating, blade coating, doctor roll, doctor blade, curtain coating, slit coating, screen printing, inkjet, and dispensing.

<Laminate>
The laminate of the embodiment includes a substrate and the above-mentioned molded article on the substrate. The laminate may have a two-layer structure or a three-layer structure or more.

The material of the substrate is not particularly limited and may be appropriately selected depending on the application. Examples of the material include wood, metal, plastic, paper, silicon, or modified silicon, and the substrate may be obtained by bonding different materials. The shape of the substrate is not particularly limited and may be any shape depending on the purpose, such as a flat plate, a sheet, or a three-dimensional shape having curvature over the entire surface or part of it. There are also no limitations on the hardness, thickness, etc. of the substrate.

The laminate can be obtained by laminating the above-mentioned molded body on the substrate. The molded body to be laminated on the substrate may be formed by direct coating or direct molding on the substrate, or a molded body of the resin composition may be laminated. In the case of direct coating, the coating method is not particularly limited, and examples thereof include spraying, spin coating, dip coating, roll coating, blade coating, doctor roll coating, doctor blade coating, curtain coating, slit coating, screen printing, and inkjet coating. In the case of direct molding, examples thereof include in-mold molding, insert molding, vacuum molding, extrusion lamination molding, and press molding. In the case of laminating a molded body made of a cured product of the resin composition, an uncured or semi-cured resin composition layer may be laminated on the substrate and then cured, or a cured product layer obtained by completely curing the resin composition may be laminated on the substrate.

The laminate may be obtained by applying a substrate precursor to a cured resin composition and curing the applied coating, or by adhering the substrate precursor or the resin composition in an uncured or semi-cured state and then curing the coating. The substrate precursor is not particularly limited, and may be any of a variety of curable resin compositions. The laminate may be produced by using the resin composition of the embodiment as an adhesive.

<Gas barrier material>
The resin composition has excellent water vapor barrier properties and oxygen barrier properties, and therefore can be suitably used as a gas barrier material. The gas barrier material may be any material that contains the above-mentioned resin composition.

<Coating Agent>
The resin composition can be suitably used as a coating agent. The coating agent may be any one that contains the above-mentioned resin composition. The coating method of the coating agent is not particularly limited. Specific examples of the coating method include various coating methods such as roll coating and gravure coating. The coating device is also not particularly limited. The resin composition has high gas barrier properties, and therefore can be suitably used as a gas barrier coating agent.

<Adhesive>
The resin composition has excellent adhesiveness and can be suitably used as an adhesive. The adhesive is not particularly limited in form, and may be a liquid or paste adhesive, or may be a solid adhesive. The resin composition has high gas barrier properties and can be suitably used as a gas barrier adhesive.

In the case of liquid or paste adhesives, there are no particular limitations on the method of use, but they may be applied to the bonding surface or injected into the interface of the bonding surfaces, then bonded and allowed to harden.

In the case of a solid adhesive, the adhesive may be formed into a powder, chip, or sheet form and placed at the interface of the bonding surfaces, thermally melted to bond and then cured.

The present invention will be explained in more detail below with reference to examples, but the present invention is not limited thereto.

<Preparation of Resin Composition>
(Preparation of resin solution)
As the vinyl resin, the following vinyl resins 1 and 2 were prepared.
Vinyl resin 1 (polyvinyl alcohol, hydroxyl value: 1250, manufactured by Nippon Vinyl Acetate & Poval Co., Ltd., JF-03)
Vinyl resin 2 (polyvinyl alcohol, hydroxyl value: 1000, manufactured by Nippon Vinyl Acetate & Poval Co., Ltd., JP-05)

65 parts by mass of ion-exchanged water and 25 parts by mass of 1-propanol were mixed, to which 8.1 parts by mass of vinyl resin 1 and 1.9 parts by mass of polyacrylic acid (manufactured by Toagosei Co., Ltd., product name: JURYMER (registered trademark) AC-10L) were added, and the mixture was heated at 85°C for 5 hours to obtain resin solution 1. Resin solutions 2 to 5 were prepared in the same manner as resin solution 1, except that the composition of each component was as shown in Table 1 (unit: parts by mass).

(Preparation of clay dispersion)
43 parts by mass of ion-exchanged water and 53 parts by mass of ethanol were mixed and stirred, and 4 parts by mass of ammonium-type bentonite (manufactured by Kunimine Kogyo Co., Ltd.) was added thereto and stirred for 30 minutes to obtain Clay Dispersion 1. The bentonite contains 82% by mass of ammonium-type montmorillonite (NH ₄ -MMT) and 18% by mass of silica. Clay Dispersions 2 to 9 were prepared in the same manner as Clay Dispersion 1, with the formulations (unit: parts by mass) shown in Table 2.

Clay dispersion 4 was prepared in the same manner as clay dispersion 1, except that ammonium bentonite was purified to contain 95% by mass of ammonium montmorillonite and 5% by mass of silica.

Clay dispersion 5 was prepared in the same manner as clay dispersion 1, except that lithium-type bentonite (Li-MMT) was used, which was obtained by exchanging the sodium ions of sodium-type bentonite, a precursor of ammonium-type bentonite, with lithium ions. The lithium-type bentonite contains 82% by mass of lithium-type montmorillonite and 18% by mass of silica.

Clay dispersion 6 was prepared in the same manner as clay dispersion 1, except that sodium bentonite (Na-MMT), a precursor of ammonium bentonite, was used. The sodium bentonite contains 82% by mass of sodium montmorillonite and 18% by mass of silica.

Clay dispersion 8 was prepared in the same manner as clay dispersion 1, except that ammonium-type bentonite obtained by exchanging the sodium ions of sodium-type bentonite (CLOISITE-Na+, BYK Japan Co., Ltd.) with ammonium ions was used. The ammonium-type bentonite contains 99% by mass of ammonium-type montmorillonite and 1% by mass of silica.

The sum of the ammonium ion equivalent, lithium ion equivalent, and hydrogen ion equivalent of the dioctahedral smectite was 72 meq/100 g for ammonium montmorillonite, 72 meq/100 g for lithium montmorillonite, and 72 meq/100 g for sodium montmorillonite.

The sodium ion equivalent of ammonium-type montmorillonite and lithium-type montmorillonite was less than 10 meq/100 g.

Example 1
20 parts by mass of clay dispersion 1 was added to 10 parts by mass of resin solution 1 and stirred for 30 minutes to prepare resin composition 1 of Example 1. The obtained resin composition 1 was applied to the corona-treated surface of a corona-treated 12 μm PET film (product name: E-5100, manufactured by Toyobo Co., Ltd.) using a bar coater so that the coating amount after drying would be 0.5 g/m ^2. The coated PET film was immediately heat-treated in a dryer at 80 ° C. for 1 minute after coating to obtain a laminated film for measuring oxygen transmission rate and water vapor transmission rate.

(Examples 2 to 10, Comparative Examples 1 and 2)
A resin composition was prepared by mixing 10 parts by mass of the resin solution with 20 parts by mass of the clay dispersion in the combinations shown in Tables 3 and 4, and a laminated film was obtained in the same manner as in Example 1.

In Examples 1 to 7 and 10 and Comparative Example, the content of polycarboxylic acid (polyacrylic acid content) in the resin composition was 19% by mass based on the total content of vinyl resin having hydroxyl groups and polycarboxylic acid. In the Examples and Comparative Example, the total content of dioctahedral smectite and silica in the resin composition was 44% by mass relative to the total amount of non-volatile content (components other than solvent). The content of silica relative to the total amount of dioctahedral smectite and silica was 18% by mass in Examples 1 to 6 and 8 to 10 and Comparative Example 1, 5% by mass in Example 7, and 1% by mass in Comparative Example 2. The alcohol content relative to the total amount of solvent and the ethanol content relative to the total amount of alcohol were as shown in Tables 3 to 4. In the Examples and Comparative Example, the non-volatile content (components other than solvent) in the resin composition was 6% by mass.

<Evaluation>
The thixotropy index of the resin compositions in the examples and comparative examples, and the oxygen permeability and water vapor permeability of the resulting laminated films were evaluated by the following methods. The evaluation results are shown in Tables 3 and 4.

(Oxygen permeability)
The oxygen transmission rate was measured in accordance with JIS-K7126 (isobaric method) using an oxygen transmission rate measuring device OX-TRAN1/50 manufactured by Mocon Co., Ltd., in an atmosphere at a temperature of 23° C. and a humidity of 75% RH. Here, RH represents humidity.

(Water Vapor Transmission Rate)
The water vapor transmission rate was measured in accordance with JIS Z 0208 "Test method for moisture transmission of moisture-proof packaging materials" using a moisture transmission cup under an atmosphere of 40° C. and 90% RH.

(thixotropy index)
The viscosity of the resin composition was evaluated from the thixotropy index (TI). The TI was calculated from the ratio of the viscosity values at rotation speeds of 6 rpm and 60 rpm (viscosity at 6 rpm/viscosity at 60 rpm) using a Brookfield viscometer. The evaluation was based on the following three-level scale.
A: TI is less than 2. B: TI is 2 or more but less than 3. C: TI is 3 or more.

Claims (7)

Contains dioctahedral smectite, silica, and polyvinyl alcohol ;
The dioctahedral smectite contains, as an interlayer ion, at least one ion selected from the group consisting of ammonium ions, lithium ions, and hydrogen ions,
The resin composition, wherein the content of the silica is 4 to 25 mass% based on the total amount of the dioctahedral smectite and the silica. Further comprising a solvent,
The resin composition according to claim 1, wherein the solvent contains an alcohol, and the content of the alcohol is 20 to 80 mass% based on the total amount of the solvent. The resin composition according to claim 1 or 2, wherein the dioctahedral smectite is montmorillonite. The resin composition according to any one of claims 1 to 3, wherein the sodium ion equivalent of the dioctahedral smectite is less than 10 meq/100 g. The resin composition according to any one of claims 1 to 4, wherein the total of the ammonium ion equivalent, lithium ion equivalent, and hydrogen ion equivalent of the dioctahedral smectite is 50 to 120 meq/100 g. The resin composition according to any one of claims 1 to 5, further comprising a polycarboxylic acid. The resin composition according to any one of claims 1 to 6, wherein the polyvinyl alcohol has a hydroxyl value of 800 to 1,500.