Aqueous dispersion, aqueous dispersion composition, and coating film

Abstract

To provide an aqueous dispersion that finely and stably contains polyphenylene ether resin in aqueous medium and forms a coating layer to exhibit a variety of excellent properties.SOLUTION: An aqueous dispersion contains a polyphenylene ether resin containing an unsaturated carboxylic acid component, and aqueous medium. The polyphenylene ether resin has an acid value of 1-150 mgKOH / g. The aqueous dispersion preferably has a basic compound. The basic compound is preferably ammonia or an organic amine compound with a boiling point of 250°C or lower.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an aqueous dispersion, an aqueous dispersion-containing product, and a coating film.

Background Art

[0002] Polyphenylene ether resin is excellent in high-frequency characteristics (i.e., dielectric characteristics) such as dielectric constant and dielectric loss tangent and has high heat resistance, so it is suitably used as an insulating material for electronic circuit boards of electronic devices. For example, Patent Document 1 describes using a dispersion liquid in which a polyphenylene ether resin is dispersed in the production of prepreg.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide an aqueous dispersion of a polyphenylene ether resin that is more excellent in various performances (adhesiveness, heat aging adhesiveness, film-forming property, water resistance, dielectric characteristics) when formed into a coating film as compared with conventional aqueous dispersions.

Means for Solving the Problems

[0005] As a result of intensive studies to solve the above problems, the present inventors have found that a polyphenylene ether resin having a specific composition is finely and stably dispersed in an aqueous medium and is further excellent in various performances when formed into a coating film, and thus have reached the present invention.

[0006] That is, the gist of the present invention is as follows (1) to ( 5 ). (1) A polyphenylene ether resin containing an unsaturated carboxylic acid component, basic compound,An aqueous dispersion containing an aqueous medium, wherein the acid value of the polyphenylene ether resin is 1 to 150 mgKOH / g and the basic compound is ammonia or an organic amine compound having a boiling point of 250°C or lower , the aqueous dispersion. ( 2 ) containing a crosslinking agent, (1) water aqueous dispersion. ( 3 )(1) or (2) An aqueous dispersion-containing composition containing the aqueous dispersion of ( 4 ) selected from adhesives, coating agents, primers, inks, varnishes, and paints ( 3 ) aqueous dispersion-containing composition. ( 5 )(1) or (2) A coating film obtained from the aqueous dispersion of

Advantages of the Invention

[0007] According to the present invention, an aqueous dispersion of a polyphenylene ether resin excellent in various performances when formed into a coating film can be provided.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0009] The present invention will be described in detail below. The aqueous dispersion of the present invention contains a polyphenylene ether resin containing an unsaturated carboxylic acid component and an aqueous medium.

[0010] In the aqueous dispersion of the present invention, the acid value of the polyphenylene ether resin needs to be 1 to 150 mgKOH / g, preferably 5 to 120 mgKOH / g, and more preferably 10 to 50 mgKOH / g. When the acid value is less than 1 mgKOH / g, it becomes difficult to disperse the resin, and it becomes difficult to obtain a good aqueous dispersion. On the other hand, when the acid value exceeds 150 mgKOH / g, the adhesiveness to various substrates, hot adhesion, or dielectric properties when formed into a coating film are impaired. Further, when a crosslinking agent is contained, the crosslinking reaction proceeds excessively and the storage stability is poor.

[0011] Examples of the unsaturated carboxylic acid component include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, aconitic acid, aconitic anhydride, fumaric acid, crotonic acid, citraconic acid, mesaconic acid, allyl succinic acid, etc. In addition, compounds having at least one carboxyl group or acid anhydride group in the molecule (within the monomer unit), such as half esters and half amides of unsaturated dicarboxylic acids, can be mentioned. Among them, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, and fumaric acid are preferable, and maleic anhydride and fumaric acid are particularly preferable from the viewpoint of ease of copolymerization with the polyphenylene ether resin.

[0012] In addition, when a polyphenylene ether resin containing an acid component other than the unsaturated carboxylic acid component (for example, a sulfonic acid component) is used, only an aqueous dispersion having poor storage stability, adhesiveness to various substrates, hot adhesion, and water resistance can be obtained.

[0013] From the viewpoint of making the acid value within the above range, the content of the unsaturated carboxylic acid component in the polyphenylene ether resin is preferably 0.4 to 13% by mass, and more preferably 0.8 to 8% by mass.

[0014] The unsaturated carboxylic acid component only needs to be contained in the polyphenylene ether resin, and its form is not limited. For example, random copolymerization, block copolymerization, graft copolymerization, etc. can be mentioned. The unsaturated carboxylic acid component introduced into the polyphenylene ether resin tends to adopt an acid anhydride structure in the dry state, and in an aqueous medium containing a basic compound described later, part or all of it tends to ring-open to form a carboxylic acid or its salt.

[0015] The method of introducing the unsaturated carboxylic acid component into the unmodified polyphenylene ether resin is not particularly limited. For example, in the presence of a radical generator, the unmodified polyphenylene ether resin and the unsaturated carboxylic acid component are heated and melted above the melting point of the unmodified polyphenylene ether resin for reaction, or after dissolving the unmodified polyphenylene ether resin and the unsaturated carboxylic acid component in an organic solvent, they are heated and stirred in the presence of a radical generator for reaction. These methods can be used to introduce the unsaturated carboxylic acid component into the unmodified polyphenylene ether resin.

[0016] Examples of the radical generator include organic peroxides such as di-tert-butyl peroxide, dicumyl peroxide, tert-butyl hydroperoxide, tert-butyl cumyl peroxide, benzoyl peroxide, dilauryl peroxide, cumene hydroperoxide, tert-butyl peroxybenzoate, ethyl ethyl ketone peroxide, di-tert-butyl diperphthalate, and azo compounds such as azobisisobutyronitrile. Compounds such as 2,3-dimethyl-2,3-diphenylbutane, 2,3-diethyl-2,3-diphenylbutane, 2,3-diethyl-2,3-diphenylhexane, and 2,3-diethyl-2,3-di(p-methylphenyl)butane can also be used as radical generators. These can be appropriately selected and used according to the reaction temperature.

[0017] The polyphenylene ether resin may contain components other than the unsaturated carboxylic acid component as long as the effects of the present invention are not impaired.

[0018] The number average molecular weight of the polyphenylene ether resin is preferably from 2,000 to 50,000, more preferably from 4,000 to 40,000, and even more preferably from 7,000 to 25,000. When the number average molecular weight of the polyphenylene ether resin is less than 2,000, the film-forming property of the resulting coating film may be inferior. When the number average molecular weight of the polyphenylene ether resin exceeds 50,000, it becomes difficult to make the resin water-soluble, and it may be difficult to obtain a good aqueous dispersion.

[0019] In the aqueous dispersion of the present invention, the above-mentioned polyphenylene ether resin is dispersed or dissolved in an aqueous medium. Here, the aqueous medium is a medium composed of a liquid mainly containing water, and may contain a water-soluble organic solvent described later as long as the effects of the present invention are not impaired. Further, it is preferable to contain a basic compound described later.

[0020] In addition, from the viewpoint of improving the storage stability of the aqueous dispersion, the number average particle diameter (hereinafter, mn) of the polyphenylene ether resin particles dispersed in the aqueous dispersion of the present invention is preferably 1 μm or less, more preferably 0.7 μm or less from the viewpoint of film-forming property, and even more preferably 0.4 μm or less. Further, regarding the volume average particle diameter (hereinafter, mv), it is preferably 1 μm or less, more preferably 0.7 μm or less, and even more preferably 0.4 μm or less.

[0021] The content of the polyphenylene ether resin contained in the aqueous dispersion of the present invention is preferably 1 to 60% by mass, and more preferably 5 to 50% by mass. When the content of the polyphenylene ether resin exceeds 60% by mass, the dispersed polyphenylene ether resin tends to aggregate, and the stability may be poor. When the content of the polyphenylene ether resin is less than 1% by mass, it is necessary to increase the coating amount of the aqueous dispersion in order to sufficiently obtain the film thickness of the coating film, and uniform coating may be difficult.

[0022] The aqueous dispersion of the present invention preferably does not substantially contain a non-volatile aqueous solubilizing agent. Even without using these, the polyphenylene ether resin can be maintained in a fine state (for example, the number average particle diameter is 1 μm or less) and stably in an aqueous medium. In the case of an aqueous dispersion substantially containing a non-volatile aqueous solubilizing agent, the non-volatile aqueous solubilizing agent may remain after the formation of the coating film or bleed out on the surface of the coating film, which may deteriorate the properties of the polyphenylene ether resin (for example, adhesiveness, hot adhesiveness, film-forming property, water resistance, etc.). "Substantially not containing a non-volatile aqueous solubilizing agent" means that the non-volatile aqueous solubilizing agent is not actively added to the system, and as a result, these are not contained. Such non-volatile aqueous solubilizing agents preferably have a content of zero, but may be contained in an amount of less than 0.1% by mass with respect to the polyphenylene ether resin as long as the effects of the present invention are not impaired.

[0023] Here, the "aqueous solubilizing agent" refers to a chemical or compound added for the purpose of promoting aqueous solubilization or stabilizing the aqueous dispersion in the production of the aqueous dispersion. "Non-volatile" means having no boiling point at normal pressure or having a high boiling point (for example, 300 °C or higher) at normal pressure.

[0024] Examples of the non-volatile aqueous solubilizing agent include, for example, an emulsifier described later, a compound having a protective colloid action, modified waxes, acid-modified compounds having a high acid value, water-soluble polymers, and the like. Examples of the emulsifier include cationic emulsifiers, anionic emulsifiers, nonionic emulsifiers, or amphoteric emulsifiers. In addition to those generally used in emulsion polymerization, surfactants are also included. For example, examples of the anionic emulsifier include sulfate salts of higher alcohols, higher alkyl sulfonates, higher carboxylates, alkylbenzene sulfonates, polyoxyethylene alkyl sulfate salts, polyoxyethylene alkyl phenyl ether sulfate salts, vinyl sulfosuccinates, etc. Examples of the nonionic emulsifier include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyethylene glycol fatty acid esters, ethylene oxide-propylene oxide block copolymers, polyoxyethylene fatty acid amides, compounds having a polyoxyethylene structure such as ethylene oxide-propylene oxide copolymers, or sorbitan derivatives such as polyoxyethylene sorbitan fatty acid esters, etc. Examples of the amphoteric emulsifier include lauryl betaine, lauryl dimethylamine oxide, etc.

[0025] Examples of the compound having a protective colloid action, modified waxes, acid-modified compounds having a high acid value, and water-soluble polymers include polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, modified starch, polyvinyl pyrrolidone, polyacrylic acid and its salts, acid-modified polyolefin waxes having a number average molecular weight of usually 5000 or less such as carboxyl group-containing polyethylene wax, carboxyl group-containing polypropylene wax, carboxyl group-containing polyethylene-propylene wax and their salts, acrylic acid-maleic anhydride copolymers and their salts, styrene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid copolymers, isobutylene-maleic anhydride alternating copolymers, carboxyl group-containing polymers having an unsaturated carboxylic acid content of 10% by mass or more such as (meth)acrylic acid-(meth)acrylic acid ester copolymers and their salts, polyitaconic acid and its salts, water-soluble acrylic copolymers having an amino group, gelatin, gum arabic, casein, etc., and compounds generally used as dispersion stabilizers for fine particles.

[0026] The aqueous dispersion of the present invention preferably contains a basic compound. Thereby, the unsaturated carboxylic acid component introduced into the polyphenylene ether resin is neutralized by the basic compound, and the aggregation between the fine particles is suppressed by the electrostatic repulsive force between the generated anions, further improving the stability of the aqueous dispersion. The basic compound may be any one that can neutralize an ionic functional group. From the viewpoint that it is difficult to remain when formed into a coating film, a volatile basic compound is preferable for the purpose of being added in this way.

[0027] As the basic compound, for example, from the viewpoint of water resistance when the aqueous dispersion of the present invention is formed into a coating film, ammonia or an organic amine compound that volatilizes during coating film formation is preferable. Among them, an organic amine compound having a boiling point of 250 ° C or lower, more preferably 200 ° C or lower is preferable. When the boiling point exceeds 250 ° C, it may be difficult to scatter the organic amine compound from the coating film by drying, and the water resistance of the coating film may deteriorate.

[0028] Specific examples of the organic amine compound include triethylamine, N,N-dimethylethanolamine, aminoethanolamine, N-methyl-N,N-diethanolamine, isopropylamine, iminobispropylamine, ethylamine, diethylamine, 3-ethoxypropylamine, 3-diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, 3-methoxypropylamine, monoethanolamine, morpholine, N-methylmorpholine, N-ethylmorpholine and the like.

[0029] The aqueous dispersion of the present invention may contain an organic solvent as long as the effects of the present invention are not impaired, in order to promote the water solubilization of the polyphenylene ether resin and reduce the dispersed particle size. It is preferable that the content of the organic solvent is small, preferably 50% by mass or less, more preferably 40% by mass or less, and particularly preferably 35% by mass or less in the aqueous medium. When the content of the organic solvent exceeds 50% by mass, it is hardly substantially an aqueous medium, not only deviating from environmental protection and the like, but also the storage stability and film-forming property of the aqueous dispersion may decrease depending on the type of the organic solvent.

[0030] Specific examples of the organic solvent used in the present invention include alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, tert-amyl alcohol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol, cyclohexanol, etc.; ketones such as methyl ethyl ketone, methyl isobutyl ketone, ethyl butyl ketone, cyclohexanone, isophorone, etc.; ethers such as tetrahydrofuran, dioxane, etc.; esters such as ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, 3-methoxybutyl acetate, methyl propionate, ethyl propionate, diethyl carbonate, dimethyl carbonate, etc.; glycol derivatives such as ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol ethyl ether acetate, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol ethyl ether acetate, propylene glycol, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol methyl ether acetate, etc.; and further 3-methoxy-3-methylbutanol, 3-methoxybutanol, acetonitrile, dimethylformamide, dimethylacetamide, diacetone alcohol, ethyl acetoacetate, etc. Among them, those having a boiling point of 30 to 250 ° C are preferred, and those having a boiling point of 50 to 200 ° C are particularly preferred. These organic solvents may be used as a mixture of two or more kinds. When the boiling point of the organic solvent is less than 30 ° C, the proportion volatilized during the water-based conversion of the resin may increase, and the efficiency of the water-based conversion may not increase sufficiently. An organic solvent having a boiling point exceeding 250 ° C is difficult to disperse from the coating film by drying, and the water resistance of the coating film may deteriorate.

[0031] Among the above organic solvents, ethanol, n-propanol, isopropanol, n-butanol, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether are preferred because they are highly effective in promoting the water solubilization of resins and are easily removable from the aqueous medium.

[0032] It is preferable that a part of the organic solvent contained in the aqueous dispersion of the present invention is distilled off outside the system by a desolventization operation called stripping. To distill off the organic solvent by stripping, treatments in the production process such as increasing the degree of vacuum of the apparatus or lengthening the operation time are required. Therefore, the lower limit of the amount of the organic solvent in consideration of such productivity is about 0.01% by mass (the detection limit of the analytical instrument used in the measurement of the present invention). However, even if it is less than 0.01% by mass, the performance as an aqueous dispersion is not particularly problematic. The aqueous dispersion of the present invention can be preferably used for various applications without particularly affecting the performance even if the organic solvent is not distilled off by the desolventization operation.

[0033] Examples of the stripping method include heating the aqueous dispersion while stirring it under normal pressure or reduced pressure to distill off the organic solvent. The content of the organic solvent can be quantified by gas chromatography. Further, since the solid content concentration increases when the aqueous medium is distilled off, for example, when the viscosity increases and the workability deteriorates, water can be added to the aqueous dispersion in advance.

[0034] As the organic solvent, it is preferable to use one having at least one atom (specifically, oxygen, nitrogen, fluorine, chlorine) with a Pauling electronegativity of 3.0 or more in the molecule from the viewpoint of obtaining a good aqueous dispersion. Further, among them, those having a solubility in water at 20 ° C of 5 g / L or more are preferable, and more preferably 10 g / L or more.

[0035] The aqueous dispersion of the present invention may contain a crosslinking agent, other polymers, tackifiers, inorganic particles, pigments, dyes, etc. in order to further improve the performance according to the purpose.

[0036] As the crosslinking agent, a crosslinking agent having self-crosslinking properties, a compound having a plurality of functional groups reactive with an unsaturated carboxylic acid component in the molecule, a metal having a polyvalent coordination site, etc. can be used. Specifically, an oxazoline group-containing compound, an isocyanate group-containing compound, an epoxy group-containing compound, a carbodiimide group-containing compound, a melamine compound, a urea compound, a zirconium salt compound, a silane coupling agent, etc. can be mentioned, and a plurality of them may be mixed and used as necessary. Among them, from the viewpoint of ease of handling, an oxazoline group-containing compound, an isocyanate group-containing compound, and an epoxy group-containing compound are preferable.

[0037] The oxazoline group-containing compound is not particularly limited as long as it has at least two or more oxazoline groups in the molecule. For example, compounds having an oxazoline group such as 2,2′-bis(2-oxazoline), 2,2′-ethylene-bis(4,4′-dimethyl-2-oxazoline), 2,2′-p-phenylene-bis(2-oxazoline), bis(2-oxazolinylcyclohexane) sulfide, etc., and oxazoline group-containing polymers can be mentioned. One or two or more of these can be used. Among these, an oxazoline group-containing polymer is preferable from the viewpoint of ease of handling.

[0038] The oxazoline group-containing polymer can be obtained, for example, by polymerizing an addition-polymerizable oxazoline such as 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline. Other monomers may be copolymerized with the oxazoline group-containing polymer as necessary. The polymerization method of the oxazoline group-containing polymer is not particularly limited, and a known polymerization method can be adopted.

[0039] Examples of commercially available oxazoline group-containing polymers include the Epocross series manufactured by Nippon Shokubai Co., Ltd., such as the water-soluble types "WS-500" and "WS-700"; and the emulsion types "K-1010E", "K-1020E", "K-1030E", "K-2010E", "K-2020E", "K-2030E", etc.

[0040] The isocyanate group-containing compound is not particularly limited as long as it has at least two or more isocyanate groups in the molecule. For example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane 2,4'- or 4,4'-diisocyanate, polymethylene polyphenyl diisocyanate, tolidine diisocyanate, 1,4-diisocyanatobutane, hexamethylene diisocyanate, 1,5-diisocyanato-2,2-dimethylpentane, 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane, 1,10-diisocyanatodecane, 1,3- or 1,4-diisocyanatocyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane, 4,4'-diisocyanatodicyclohexylmethane, hexahydrotoluene 2,4- or 2,6-diisocyanate, perhydro-2,4'- or 4,4'-diphenylmethane diisocyanate, naphthalene 1,5-diisocyanate, xylylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, tetramethylxylylene diisocyanate and other polyfunctional isocyanate compounds, or modified products thereof can be mentioned. Here, the modified product is obtained by modifying the diisocyanate among the polyfunctional isocyanate compounds by a known method. For example, polyfunctional isocyanate compounds having an allophanate group, a biuret group, a carbodiimide group, a uretonimine group, a uretdione group, an isocyanurate group, etc., and further, adduct-type polyfunctional isocyanate compounds modified with polyfunctional alcohols such as trimethylolpropane can be mentioned. In addition, the isocyanate group-containing compound may contain monoisocyanate in the range of 20% by mass or less. Also, one or more of these can be used.

[0041] Isocyanate group-containing compounds can usually be obtained by reacting polyfunctional isocyanate compounds with monovalent or polyvalent nonionic polyalkylene ether alcohols. Examples of commercially available products of such aqueous polyfunctional isocyanate compounds include, for example, Bayhydur 3100, Bayhydur VPLS2150 / 1, SBU Isocyanate L801, Desmodur N3400, Desmodur VPLS2102, Desmodur VPLS2025 / 1, SBU Isocyanate 0772, Desmodur DN manufactured by Sumitomo Bayer Urethane Co., Ltd.; Takenate WD720, Takenate WD725, Takenate WD730 manufactured by Takeda Pharmaceutical Company Limited; Duranate WB40-100, Duranate WB40-80D, Duranate WX-1741 manufactured by Asahi Kasei Corporation; Basonat HW-100, Basonat LR-9056 manufactured by BASF Corporation, etc.

[0042] The epoxy group-containing compound is not particularly limited as long as it has at least two or more epoxy groups in the molecule. For example, bisphenol A diglycidyl ether, bisphenol A β-dimethylglycidyl ether, bisphenol F diglycidyl ether, tetrahydroxyphenylmethane tetraglycidyl ether, resorcinol diglycidyl ether, brominated bisphenol A diglycidyl ether, chlorinated bisphenol A diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, diglycidyl ether of bisphenol A alkylene oxide adduct, novolac glycidyl ether, polyalkylene glycol diglycidyl ether, glycerin triglycidyl ether, pentaerythritol diglycidyl ether, glycidyl ether type such as epoxy urethane resin; glycidyl ether-ester type such as glycidyl ether-ester of p-oxybenzoic acid; glycidyl ester type such as diglycidyl phthalate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, diglycidyl acrylate, diglycidyl dimer acid; glycidyl amine type such as glycidyl aniline, tetraglycidyl diaminodiphenylmethane, triglycidyl isocyanurate, triglycidyl aminophenol; linear aliphatic epoxy resins such as epoxidized polybutadiene, epoxidized soybean oil; alicyclic epoxy resins such as 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxylate, 3,4-epoxycyclohexylmethyl(3,4-epoxycyclohexane)carboxylate, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, vinylcyclohexene diepoxide, dicyclopentadiene monoxide, bis(2,3-epoxycyclopentyl)ether, limonene dioxide, etc. One or more of these can be used.

[0043] Examples of commercially available epoxy group-containing compounds suitable for the present invention include aqueous ones such as the Denacol series (EX-313, EM-150, EM-101, etc.) manufactured by Nagase ChemteX Corporation, and the Adeka Resin series (EM-0517, EM-0526, EM-11-50B, EM-051R) manufactured by ADEKA Corporation.

[0044] The melamine compound is not particularly limited as long as it has a melamine skeleton in the molecule. For example, alkylolated melamine derivatives, compounds obtained by reacting an alkylolated melamine derivative with an alcohol to partially or completely etherify it, and mixtures thereof can be used. As the alcohol used for etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol, etc. are preferably used. Further, the melamine compound may be a monomer or a multimer of dimer or higher, and mixtures thereof may also be used.

[0045] Examples of commercially available melamine compounds include Cymel 323, Cymel 325, Cymel 327, Cymel 328, Cymel 370, etc. manufactured by Nippon Cytec Industries Co., Ltd.

[0046] The carbodiimide group-containing compound is not particularly limited as long as it has at least two or more carbodiimide groups in the molecule. For example, compounds having a carbodiimide group such as p-phenylene-bis(2,6-xylylcarbodiimide), tetramethylene-bis(t-butylcarbodiimide), cyclohexane-1,4-bis(methylene-t-butylcarbodiimide), and polycarbodiimide which is a polymer having a carbodiimide group can be mentioned. One or more of these can be used. Among these, polycarbodiimide is preferable from the viewpoint of ease of handling. Examples of commercially available polycarbodiimides include the Carbodilite series manufactured by Nisshinbo. Specific products include, for example, water-soluble types such as "SV-02", "V-02", "V-02-L2", "V-04"; emulsion types such as "E-01", "E-02"; organic solution types such as "V-01", "V-03", "V-07", "V-09"; and solvent-free types such as "V-05".

[0047] From the viewpoint of improving the heat resistance or water resistance of the coating film, etc., the content of the crosslinking agent is preferably 0.01 to 80 parts by mass, more preferably 0.1 to 50 parts by mass, and even more preferably 0.5 to 30 parts by mass with respect to 100 parts by mass of the polyphenylene ether resin. If the content of the crosslinking agent is less than 0.01 part by mass, the improvement of the coating film performance may not be sufficient, and if it exceeds 80 parts by mass, the dielectric properties, etc. may deteriorate.

[0048] Other polymers and tackifiers are not particularly limited. For example, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylate-maleic anhydride copolymer, styrene-maleic acid resin, styrene-butadiene resin, butadiene resin, acrylonitrile-butadiene resin, polyurethane resin, poly(meth)acrylonitrile resin, (meth)acrylamide resin, chlorinated polyethylene resin, chlorinated polypropylene resin, polyester resin, modified nylon resin, tackifying resins such as rosin, phenolic resin, silicone resin, epoxy resin, etc. may be mentioned, and a plurality of them may be mixed and used as necessary. These polymers may be used as they are in solid form, but from the viewpoint of maintaining the stability of the aqueous dispersion, it is preferable to use those processed into an aqueous dispersion.

[0049] Examples of the inorganic particles include metal oxides such as magnesium oxide, zinc oxide, and tin oxide, inorganic particles such as calcium carbonate and silica, and layered inorganic compounds such as vermiculite, montmorillonite, hectorite, hydrotalcite, and synthetic mica. From the viewpoint of the stability of the aqueous dispersion, the average particle diameter of these inorganic particles is preferably 0.005 to 10 μm, and more preferably 0.005 to 5 μm. A plurality of inorganic particles may be mixed and used. Zinc oxide can be used for the purpose of ultraviolet shielding, and tin oxide can be used for the purpose of antistatic.

[0050] Examples of the pigments and dyes include titanium oxide, zinc white, carbon black, etc., and any of disperse dyes, acid dyes, cationic dyes, reactive dyes, etc. can be used. Various agents such as leveling agents, defoaming agents, anti-sagging agents, pigment dispersants, ultraviolet absorbers, thickeners, weathering agents, and flame retardants can also be added to the aqueous dispersion of the present invention as necessary.

[0051] The method for producing the aqueous dispersion of the present invention is not particularly limited. For example, a method of heating and stirring each of the above-described components, that is, a polyphenylene ether resin, an aqueous medium, and, if necessary, a basic compound, etc. in a preferably sealable container can be employed, and this method is most preferred. According to this method, the polyphenylene ether resin can be made into an aqueous dispersion even better without substantially adding a non-volatile aqueous aid such as an emulsifier component or a compound having a protective colloid action.

[0052] The shape of the polyphenylene ether resin used for water dispersion is not particularly limited. From the viewpoint of accelerating the water dispersion rate, preferably, granular or powdery ones with a particle diameter of 1 cm or less, more preferably 0.8 cm or less can be used.

[0053] As the container, any container that can be charged with a liquid and can appropriately stir the mixture of the aqueous medium and the polyphenylene ether resin charged into the tank may be used. As such a device, for example, a device widely known to those skilled in the art as a solid / liquid stirrer or an emulsifier can be used, and it is preferable to use a device capable of applying a pressure of 0.1 MPa or more. The stirring method and the rotational speed of stirring in the present invention are not particularly limited. However, sufficient water dispersion can be achieved even with a low-speed stirring to the extent that the resin is in a floating state in the aqueous medium, and high-speed stirring (for example, 1000 rpm or more) is not essential. Therefore, an aqueous dispersion can be produced even with a simple device.

[0054] Into the tank of such an apparatus, an aqueous medium, a polyphenylene ether resin, and, if necessary, a basic compound or the like are charged, and preferably stirred and mixed at a temperature of 40°C or lower. Next, while maintaining the temperature in the tank at 80 to 220°C, preferably 90 to 210°C, more preferably 100 to 200°C, stirring is preferably continued for 5 to 120 minutes to sufficiently hydrophilize the polyphenylene ether resin, and then, preferably cooled to 40°C or lower with stirring to obtain an aqueous dispersion. If the temperature in the tank is less than 80°C, it may be difficult to hydrophilize the polyphenylene ether resin. If the temperature in the tank exceeds 220°C, a large amount of energy will be consumed. As a heating method for the tank, heating from the outside of the tank is preferred. For example, heating of the tank using oil or water, or heating with a heater attached to the tank can be performed. As a cooling method for the tank, for example, a method of natural cooling at room temperature, or a method of cooling using oil or water at 0 to 40°C can be mentioned.

[0055] As a method for adjusting the solid content concentration of the aqueous dispersion thus obtained, for example, a method of distilling off the aqueous medium so as to obtain a desired solid content concentration, or a method of diluting with water can be mentioned.

[0056] As described above, the aqueous dispersion of the present invention is produced by dispersing or dissolving a polyphenylene ether resin in an aqueous medium and preparing it in a uniform liquid state. Here, being in a uniform liquid state means that, in appearance, there is no part where the solid content concentration is locally different from other parts, such as precipitation, phase separation, or skin formation, in the aqueous dispersion.

[0057] As a method of using the aqueous dispersion of the present invention, for example, an aqueous dispersion-containing composition containing the aqueous dispersion of the present invention can be mentioned. Examples of the aqueous dispersion-containing composition include adhesives, coating agents, primers, inks, varnishes, pigments, and the like.

[0058] Since the aqueous dispersion of the present invention is excellent in film-forming ability, it can be uniformly coated on the surfaces of various substrates by known film-forming methods, such as gravure roll coating, reverse roll coating, wire bar coating, lip coating, air knife coating, curtain flow coating, spray coating, dip coating, brush coating method, etc. After setting at around room temperature as necessary, it is subjected to drying or heat treatment for drying and baking, whereby a uniform coating film can be formed in close contact with the surfaces of various substrates. The heating device at this time is not particularly limited, and a normal hot air circulation type oven, an infrared heater, etc. may be used.

[0059] The heating temperature or heating time is appropriately selected depending on the characteristics of the substrate, etc. However, considering economy, the heating temperature is preferably 30 to 260 °C, more preferably 60 to 240 °C, and even more preferably 80 to 220 °C. The heating time is preferably 1 second to 20 minutes, more preferably 5 seconds to 15 minutes, and even more preferably 5 seconds to 10 minutes. When a crosslinking agent is added, in order to allow the reaction between the polyphenylene ether resin and the crosslinking agent to proceed sufficiently, it is desirable to appropriately select the heating temperature or time depending on the type of the crosslinking agent.

[0060] The thickness of the coating film obtained from the aqueous dispersion of the present invention is appropriately selected depending on its use, but is preferably 0.01 to 300 μm, more preferably 0.1 to 150 μm, and particularly preferably 0.2 to 80 μm. If a film is formed so that the thickness of the coating film falls within the above range, a coating film excellent in uniformity can be obtained. In order to adjust the thickness of the coating film, in addition to appropriately selecting the device used for coating and its operating conditions, it is preferable to use an aqueous dispersion having a concentration suitable for the target thickness of the coating film. The concentration at this time can be adjusted by the charged composition during preparation. Also, the concentration may be adjusted by appropriately diluting or concentrating the once-prepared aqueous dispersion.

Examples

[0061] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto. Various properties were measured or evaluated by the following methods. (1) Number average molecular weight of polyphenylene ether resin The number average molecular weight was measured in terms of standard polystyrene using gel permeation chromatography (GPC). GPC measurement was carried out using Shodex LF-804×2 (manufactured by Showa Denko K.K.) as the column, chloroform at 50 °C as the eluent, and RI (refractometer) as the detector. The number average molecular weight was calculated from the relational expression between the molecular weight and the elution time of the standard polystyrene sample measured under the same conditions.

[0062] (2) Acid value of polyphenylene ether resin In accordance with JIS K0070, the acid value was measured by the following procedures (i) to (iii). (i) Dissolve 1 g of polyphenylene ether resin in 100 g of xylene whose temperature has been adjusted to 100 °C. (ii) Using phenolphthalein as an indicator, titrate with 0.1 mol / L potassium hydroxide ethanol solution. (iii) Convert the amount of potassium hydroxide required for titration to mg and calculate the acid value (unit: mgKOH / g).

[0063] (3) Solids concentration of aqueous dispersion Weigh about 1 g of the aqueous dispersion (designated as X g), weigh the mass of the residue (solids) after drying this at 150 °C for 2 hours (designated as Y g), and determine the solids concentration by the following formula. Solids concentration (mass%) = (Y / X) × 100

[0064] (4) Viscosity of aqueous dispersion Using a Tokimec DVL-BII type digital viscometer (B-type viscometer), the rotational viscosity of the aqueous dispersion at a temperature of 20 °C was measured.

[0065] (5) Average particle diameter of polyphenylene ether resin particles It was determined using a Microtrac particle size distribution analyzer UPA150 (MODEL No.9340) manufactured by Nikkiso Co., Ltd.

[0066] (6) Storage stability of the aqueous dispersion The appearance of the aqueous dispersion left at room temperature for 90 days was visually observed and evaluated in the following three stages. ○: No change in appearance. △: Thickening was observed. ×: Solidification, aggregation, or generation of precipitate was observed.

[0067] (7) Adhesion evaluation Using a modified polyphenylene ether resin ("Zylon" manufactured by Asahi Kasei Corporation, hereinafter m-PPE), an m-PPE film with a thickness of 100 μm was obtained by the T-die method. The aqueous dispersion was applied to an aluminum foil (manufactured by Mitsubishi Aluminum Co., Ltd., thickness 15 μm, hereinafter "AL") so that the thickness of the dried coating film became 5 μm, dried at 150 °C for 40 seconds, and then the above m-PPE film and the coating film were laminated together and pressed at 240 °C for 30 seconds using a heat press machine (sealing pressure 0.3 MPa) to obtain a laminate. This laminate was cut out with a width of 15 mm, and the peel strength at 180° peel was measured using a tensile testing machine (manufactured by Instron Corporation, Instron Precision Universal Material Testing Machine Model 2020) at a tensile speed of 100 mm / min in an atmosphere of 25 °C between the AL and m-PPE layers. The measurement was performed with n = 5, and the measured value was taken as the average value.

[0068] Similarly, as a substrate to be laminated on AL, a polyphenylene sulfide film (manufactured by Toray Industries, Inc., thickness 60 μm, hereinafter "PPS") and a copper foil (manufactured by Furukawa Electric Co., Ltd., thickness 18 μm, hereinafter "Cu") that had been subjected to one-sided corona treatment were used to evaluate the adhesion of the aqueous dispersion.

[0069] (8) Hot adhesion evaluation After producing a laminate in the same manner as in (7) above, this laminate was cut out with a width of 15 mm, and the peel strength at 180° peel was measured using a tensile testing machine (manufactured by Instron Corporation, Instron Precision Universal Material Testing Machine Model 2020) at a tensile speed of 100 mm / min in an atmosphere of 100 °C between the layers of each substrate. The measurement was performed with n = 5, and the measured value was taken as the average value.

[0070] (9) Film-forming property of the coating film The aqueous dispersion was coated onto the corona-treated surface of a biaxially stretched PET film (manufactured by Unitika, thickness 38 μm) using a desktop coating device (manufactured by Yasuda Seiki Co., Ltd., Film Applicator No. 542-AB type, equipped with a bar coater), and then dried in a hot air dryer set at 150°C for 1 minute to form a coating film with a film thickness of 1 μm. The coating film was visually observed, and the film-forming property was evaluated according to the following criteria based on whether a coating film without cracks or whitening was formed. The film thickness of the coating film was measured using a thickness gauge (manufactured by Union Tool Co., Ltd., MICROFINE). First, the thickness of the film was measured in advance. After forming a coating film on the film using the aqueous dispersion, the thickness of the substrate with this coating film was measured in the same manner, and the difference was taken as the film thickness of the coating film. ○: No cracks or whitening were observed. ×: Cracks and / or whitening were observed.

[0071] (10) Water resistance of the coating film In the same manner as in (9) above, after forming a coating film with a film thickness of 1 μm on a PET film, it was cut into test pieces measuring 50 mm × 50 mm and subjected to a hot water treatment for 10 minutes in a state where the whole was immersed in hot water at 90°C. After the hot water treatment, the test pieces were taken out, immersed in cold water and cooled for 1 minute, then the water droplets were wiped off, and the appearance of the coating film was visually observed. The water resistance was evaluated according to the following criteria based on whether it was whitened. ○: No change in appearance was observed at all. ×: Whitening was observed.

[0072] (11) Dielectric constant of the coating film A cast film with a thickness of 50 μm was prepared from the aqueous dispersion. Using this film as a test piece, measurements were carried out at 1 MHz in accordance with ASTM D-150. A lower value of the dielectric constant is an indicator of better dielectric properties.

[0073] The polyphenylene ether resins (P-1) to (P-11) used in the examples and comparative examples are shown in Table 1.

Table 1

[0074] Synthesis Example 1: Polyphenylene Ether Resin P-1 50 g of a polyphenylene ether resin (number average molecular weight 12,000) was heated and dissolved in 350 g of chlorobenzene in a four-necked flask under a nitrogen atmosphere. After that, while maintaining the system temperature at 140 °C and stirring, 9 g of maleic anhydride as an unsaturated carboxylic acid and 7 g of dicumyl peroxide as a radical generator were each added over 2 hours, and then reacted for 6 hours. After completion of the reaction, the resulting reaction product was poured into a large amount of methanol to precipitate the resin. This resin was further washed several times with methanol to remove unreacted maleic anhydride, and then dried under reduced pressure to obtain polyphenylene ether resin P-1.

[0075] Synthesis Example 2: Polyphenylene Ether Resin P-2 50 g of a polyphenylene ether resin (number average molecular weight 8,000) was heated and dissolved in 350 g of chlorobenzene in a four-necked flask under a nitrogen atmosphere. After that, while maintaining the system temperature at 140 °C and stirring, 12 g of maleic anhydride as an unsaturated carboxylic acid and 7 g of dicumyl peroxide as a radical generator were each added over 2 hours, and then reacted for 6 hours. After completion of the reaction, the resulting reaction product was poured into a large amount of methanol to precipitate the resin. This resin was further washed several times with methanol to remove unreacted maleic anhydride, and then dried under reduced pressure to obtain polyphenylene ether resin P-2.

[0076] Synthesis Example 3: Polyphenylene Ether Resin P-3 50 g of polyphenylene ether resin (number average molecular weight 52,000) was heated and dissolved in 350 g of chlorobenzene in a four-necked flask under a nitrogen atmosphere. After that, while maintaining the temperature inside the system at 140 °C and stirring, 7 g of maleic anhydride as an unsaturated carboxylic acid and 7 g of dicumyl peroxide as a radical generator were each added over 2 hours, and then reacted for 6 hours. After completion of the reaction, the resulting reaction product was poured into a large amount of methanol to precipitate the resin. This resin was further washed several times with methanol to remove unreacted maleic anhydride, and then dried under reduced pressure to obtain polyphenylene ether resin P-3.

[0077] Synthesis Example 4: Polyphenylene ether resin P-4 50 g of polyphenylene ether resin (number average molecular weight 12,000) was heated and dissolved in 350 g of chlorobenzene in a four-necked flask under a nitrogen atmosphere. After that, while maintaining the temperature inside the system at 140 °C and stirring, 1 g of maleic anhydride as an unsaturated carboxylic acid and 3 g of dicumyl peroxide as a radical generator were each added over 2 hours, and then reacted for 6 hours. After completion of the reaction, the resulting reaction product was poured into a large amount of methanol to precipitate the resin. This resin was further washed several times with methanol to remove unreacted maleic anhydride, and then dried under reduced pressure to obtain polyphenylene ether resin P-4.

[0078] Synthesis Example 5: Polyphenylene ether resin P-5 50 g of polyphenylene ether resin (number average molecular weight 12,000) was heated and dissolved in 350 g of chlorobenzene in a four-necked flask under a nitrogen atmosphere. After that, while maintaining the temperature inside the system at 140 °C and stirring, 15 g of maleic anhydride as an unsaturated carboxylic acid and 17 g of dicumyl peroxide as a radical generator were each added over 2 hours, and then reacted for 6 hours. After completion of the reaction, the resulting reaction product was poured into a large amount of methanol to precipitate the resin. This resin was further washed several times with methanol to remove unreacted maleic anhydride, and then dried under reduced pressure to obtain polyphenylene ether resin P-5.

[0079] Synthesis Example 6: Polyphenylene ether resin P-6 1 kg of polyphenylene ether resin (number average molecular weight: 20,000), 20 g of fumaric acid as an unsaturated carboxylic acid, and 20 g of 2,3-dimethyl-2,3-diphenylbutane as a radical generator were dry-blended, and melt-kneaded using a 30 mm twin-screw extruder at a screw rotation speed of 200 rpm and a set temperature of 300 °C while removing volatile components by a vacuum vent. After cooling the strands discharged from the twin-screw extruder, they were pelletized and dried under reduced pressure to obtain polyphenylene ether resin P-6.

[0080] Synthesis Example 7: Polyphenylene ether resin P-7 50 g of polyphenylene ether resin (number average molecular weight: 16,000) was heated and dissolved in 350 g of chlorobenzene in a four-necked flask under a nitrogen atmosphere. After keeping the temperature inside the system at 140 °C and stirring, 0.5 g of maleic anhydride as an unsaturated carboxylic acid and 3 g of dicumyl peroxide as a radical generator were each added over 2 hours, and then reacted for 6 hours. After completion of the reaction, the obtained reaction product was poured into a large amount of methanol to precipitate the resin. This resin was further washed several times with methanol to remove unreacted maleic anhydride, and then dried under reduced pressure to obtain polyphenylene ether resin P-7.

[0081] Synthesis Example 8: Polyphenylene ether resin P-8 50 g of polyphenylene ether resin (number average molecular weight: 12,000) was heated and dissolved in 350 g of chlorobenzene in a four-necked flask under a nitrogen atmosphere. After keeping the temperature inside the system at 140 °C and stirring, 15 g of maleic anhydride as an unsaturated carboxylic acid and 20 g of dicumyl peroxide as a radical generator were each added over 2 hours, and then reacted for 6 hours. After completion of the reaction, the obtained reaction product was poured into a large amount of methanol to precipitate the resin. This resin was further washed several times with methanol to remove unreacted maleic anhydride, and then dried under reduced pressure to obtain polyphenylene ether resin P-8.

[0082] Synthesis Example 9: Polyphenylene ether resin P-11 30 g of polyphenylene ether resin (number average molecular weight 9,200) was dissolved in 650 g of chloroform. 2.8 g of chlorosulfonic acid was added dropwise thereto over 20 minutes, and the mixture was stirred at room temperature for 2 hours for reaction. As the reaction proceeded, the supernatant was removed from the precipitated resin, and the resin was washed three times with 450 g of chloroform. Thereafter, it was dried under reduced pressure to obtain polyphenylene ether resin P-11.

[0083] Example 1 Using a stirrer equipped with a 1 L pressure-resistant glass container with a heater that can be sealed, 60 g of polyphenylene ether resin (P-1), 90 g of THF, 15 g of N,N-dimethylethanolamine (boiling point 135 °C), and 135 g of distilled water were charged into the glass container. When stirred with the rotation speed of the stirring blade set at 300 rpm, no precipitation of resin granular matter was observed at the bottom of the container, and it was confirmed that the resin was in a suspended state. Therefore, while maintaining this state, the heater was turned on and heated 10 minutes later. Then, the temperature inside the system was maintained at 120 °C and stirring was continued for another 30 minutes. Thereafter, it was placed in a water bath and cooled to room temperature (about 25 °C) while stirring, and 70 g of distilled water was added. The obtained aqueous dispersion was put into a 1 L eggplant flask, and while heating it in a hot water bath at 60 °C, it was depressurized using an evaporator to distill off 130 g of the aqueous medium. After cooling, the liquid component in the flask was pressure-filtered (air pressure 0.2 MPa) through a 300-mesh stainless steel filter (wire diameter 0.035 mm, plain weave) to obtain a milky white uniform aqueous dispersion (Em-1).

[0084] Example 2 An aqueous dispersion (Em-2) was obtained in the same manner as in Example 1 except that polyphenylene ether resin (P-2) was used.

[0085] Example 3 An aqueous dispersion (Em-3) was obtained in the same manner as in Example 1 except that polyphenylene ether resin (P-3) was used.

[0086] Example 4 An aqueous dispersion (Em-4) was obtained in the same manner as in Example 1 except that polyphenylene ether resin (P-4) was used.

[0087] Example 5 An aqueous dispersion (Em-5) was obtained in the same manner as in Example 1, except that polyphenylene ether resin (P-5) was used.

[0088] Example 6 Using a stirrer equipped with a sealable pressure-resistant 1 L glass container with a heater, 25 g of polyphenylene ether resin (P-6), 90 g of THF, 2.5 g of triethylamine (boiling point 89 °C), and 132.5 g of distilled water were charged into the glass container, and when stirred at a rotational speed of the stirring blade of 300 rpm, no precipitation of resin granular matter was observed at the bottom of the container, and it was confirmed that it was in a suspended state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was maintained at 130 °C and stirred for an additional 60 minutes. Thereafter, it was placed in a water bath and cooled to room temperature (about 25 °C) while stirring, and 200 g of distilled water was added. The obtained aqueous dispersion was placed in a 1 L eggplant flask, and while heating in a hot water bath at 60 °C, the pressure was reduced using an evaporator, and 140 g of the aqueous medium was distilled off. After cooling, the liquid component in the flask was pressure-filtered (air pressure 0.2 MPa) through a 300-mesh stainless steel filter (wire diameter 0.035 mm, plain weave) to obtain a milky white uniform aqueous dispersion (Em-6).

[0089] Comparative Example 1 Examination was carried out in the same manner as in Example 1, except that polyphenylene ether resin (P-7) was used. However, the presence of a large amount of resin was visually observed, and an aqueous dispersion in which the resin was dispersed in the aqueous medium could not be obtained.

[0090] Comparative Example 2 An aqueous dispersion (Em-7) was obtained in the same manner as in Example 1, except that polyphenylene ether resin (P-8) was used.

[0091] Comparative Example 3 To 300 g of a mixed solvent of toluene and methanol (mass ratio: 99:1), 100 g of a powdered polyphenylene ether resin (P-9) was added, and the mixture was stirred for 10 minutes (25 °C, 8,000 revolutions) using a homogenizer (HM-300 type, manufactured by AS ONE Corporation) to obtain a dispersion (Em-8).

[0092] Comparative Example 4 According to the method described in Patent Document 1, 100 g of a powdered polyphenylene ether resin P-10 passing through a JIS standard sieve opening of 140 mesh (106 μm) was added to a solvent obtained by adding 1 g of a polymeric surfactant (Discoat N-14, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) to 99 g of distilled water, and the mixture was stirred for 10 minutes (25 °C, 8,000 revolutions) using a homogenizer (HM-300 type, manufactured by AS ONE Corporation) to obtain an aqueous dispersion (Em-9).

[0093] Comparative Example 5 An aqueous dispersion (Em-10) was obtained in the same manner as in Example 1 except that a polyphenylene ether resin (P-11) was used.

[0094] Table 2 shows the compositions of the aqueous dispersions obtained in Examples 1 to 6 and Comparative Examples 1 to 5.

Table 2

[0095] Examples 6 to 8 An aqueous dispersion (Em-1) and a crosslinking agent were mixed. As the crosslinking agent, an aliphatic epoxy compound (Denacol EX-313, manufactured by Nagase ChemteX Corporation, Example 6), an isocyanate group-containing compound (Bayhydur 3100, manufactured by Sumitomo Bayer Urethane Co., Ltd., Example 7), and an oxazoline group-containing compound (Epocros WS-700, manufactured by Nippon Shokubai Co., Ltd., Example 8) were used. (Em-1) was stirred, and the amount shown in Table 3 in terms of solid content was added to 100 parts by mass of the solid content of (Em-1), and the mixture was stirred at room temperature for 30 minutes.

[0096] Comparative Example 6 An aqueous dispersion (Em-1) and an aliphatic epoxy compound (Denacol EX-313, manufactured by Nagase ChemteX Corporation) as a crosslinking agent were mixed. 10 parts by mass of the aliphatic epoxy compound in terms of solid content was added to 100 parts by mass of the solid content of the aqueous dispersion (Em-1), and the mixture was stirred at room temperature for 30 minutes.

[0097] The evaluation results of the aqueous dispersions obtained in the examples and comparative examples are summarized in Table 3.

Table 3

[0098] As shown in Table 2, in Examples 1 to 6, stable aqueous dispersions could be obtained without using a non-volatile water solubilizing aid.

[0099] The aqueous dispersion of the present invention obtained in Example 6 was dried at normal temperature and pressure, and the appearance of the polyphenylene ether resin was observed using a scanning electron microscope (manufactured by JEOL Ltd.). As a result, it had the appearance structures shown in FIGS. 1 and 2. Note that FIG. 1 is a photograph taken at a magnification of (7,000) times, and FIG. 2 is a photograph taken at a magnification of (22,000) times.

[0100] On the other hand, in Comparative Example 1, since the acid value of the polyphenylene ether resin was less than 1 mgKOH / g, it was very difficult to disperse the polyphenylene ether resin in an aqueous medium, and an aqueous dispersion could not be obtained.

[0101] As shown in Table 3, in Examples 1 to 9, they were excellent in storage stability, adhesiveness to various substrates, hot adhesion, film-forming properties, water resistance, and dielectric properties.

[0102] In Comparative Example 2, since the acid value of the polyphenylene ether resin exceeded 150 mgKOH / g, it was inferior in adhesiveness to various substrates, hot adhesion, and dielectric properties.

[0103] In Comparative Example 3, a polyphenylene ether resin not containing an unsaturated carboxylic acid component was used and dispersed using an organic solvent without using an aqueous medium as a dispersion medium. The storage stability of the obtained dispersion was very short, and it was inferior in adhesiveness and film-forming properties.

[0104] In Comparative Example 4, a polyphenylene ether resin not containing an unsaturated carboxylic acid component was used and dispersed using a non-volatile water-soluble aid. In this case, since the non-volatile water-soluble aid remained in the obtained coating film, it was inferior in film-forming properties, adhesiveness to various substrates, hot adhesiveness, and water resistance.

[0105] In Comparative Example 5, since a polyphenylene ether resin acid-modified with a sulfonic acid component instead of an unsaturated carboxylic acid component was used, it was inferior in storage stability, adhesiveness to various substrates, hot adhesiveness, and water resistance.

[0106] In Comparative Example 6, since the acid value of the polyphenylene ether resin exceeded 150 mgKOH / g, it was not only inferior in adhesiveness to various substrates and dielectric properties, but also, because a crosslinking agent was used, the reaction with the crosslinking agent proceeded excessively at room temperature, and the storage stability was very short.

Claims

1. An aqueous dispersion containing a polyphenylene ether resin containing an unsaturated carboxylic acid component, a basic compound, and an aqueous medium, wherein the acid value of the polyphenylene ether resin is 1 to 150 mgKOH / g, and the basic compound is ammonia or an organic amine compound having a boiling point of 250°C or lower. The aqueous dispersion.

2. The aqueous dispersion according to claim 1, containing a crosslinking agent.

3. An aqueous dispersion-containing product containing the aqueous dispersion according to claim 1 or 2.

4. The aqueous dispersion-containing product according to claim 3, selected from an adhesive, a coating agent, a primer, an ink, a varnish, and a paint.

5. A coating film obtained from the aqueous dispersion according to claim 1 or 2.

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