Water-based resin composition, water-based paint, and plastic molded product coated with the water-based paint

Abstract

Provided is an aqueous resin composition, characterized in that it contains a polycarbonate-modified acrylic resin and an aqueous medium, wherein the polycarbonate-modified acrylic resin is a reaction product of a polycarbonate diol (A) with 1,4-butanediol as a necessary raw material and an unsaturated monomer mixture (B), wherein the unsaturated monomer mixture (B) contains methyl methacrylate, an unsaturated monomer (b1) having a hydroxyl group, an unsaturated monomer (b2) having a carboxyl group, and an unsaturated monomer (b3) having an alicyclic structure as a necessary component, and the ratio of the unsaturated monomer (b3) in the unsaturated monomer mixture (B) is in the range of 3 to 60% by mass. The aqueous resin composition has high adhesion to a plastic substrate, and can obtain a coating film having excellent water-resistant adhesion and aromatic resistance, and is therefore suitable for use in water-based coatings and plastic molded products.

Description

Technical Field

[0001] The present invention relates to a water-based resin composition, a water-based paint and a plastic molded product coated with the water-based paint. Background Art

[0002] Conventionally, polycarbonate-modified acrylic resins obtained by reacting unsaturated monomers in the presence of polyols have been proposed, and it is known that the cured coating films thereof have excellent adhesion to substrates, mechanical properties, and the like (see, for example, Patent Document 1).

[0003] On the other hand, in recent years, in the paint industry, from the perspective of environmental protection and non-hazardous materialization of paints, the replacement of solvent-based paints with water-based paints is being carried out. However, in the water-based conversion of polycarbonate-modified acrylic resins as described above, there are problems such as insufficient adhesion to substrates and insufficient water resistance.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 6249212 Summary of the invention

[0007] Problems to be solved by the invention

[0008] The problem to be solved by the present invention is to provide an aqueous resin composition having high adhesion to a plastic substrate and capable of obtaining a coating film having excellent water-resistant adhesion and fragrance resistance, a coating material, and a plastic molded product coated with the coating material.

[0009] Means for solving problems

[0010] The present inventors have conducted intensive studies to solve the above-mentioned problems and have found that a coating film having high adhesion to a plastic substrate, excellent water-resistant adhesion and fragrance resistance can be obtained by using an aqueous resin composition containing a polycarbonate-modified acrylic resin and an aqueous medium, wherein the polycarbonate-modified acrylic resin is a reaction product of the specific polycarbonate diol and an unsaturated monomer mixture containing a specific unsaturated monomer as an essential component, thereby completing the invention.

[0011] That is, the present invention relates to an aqueous resin composition, characterized in that it contains a polycarbonate-modified acrylic resin and an aqueous medium, wherein the polycarbonate-modified acrylic resin is a reaction product of a polycarbonate diol (A) having 1,4-butanediol as an essential raw material and an unsaturated monomer mixture (B), wherein the unsaturated monomer mixture (B) contains methyl methacrylate, an unsaturated monomer (b1) having a hydroxyl group, an unsaturated monomer (b2) having a carboxyl group, and an unsaturated monomer (b3) having an alicyclic structure as essential components, and the ratio of the unsaturated monomer (b3) in the unsaturated monomer mixture (B) is in the range of 3 to 60% by mass.

[0012] Effects of the Invention

[0013] The water-based resin composition of the present invention can obtain a coating film having high adhesion to a plastic substrate, excellent water-resistant adhesion and fragrance resistance, and is therefore useful for coatings, and the coating can be applied to various plastic molded products. Therefore, the polycarbonate-modified acrylic resin of the present invention can be suitably used for coatings for various articles, such as housings of electronic devices such as mobile phones, smart phones, tablet terminals, personal computers, digital cameras, and game consoles; housings of home appliances such as televisions, refrigerators, washing machines, and air conditioners; and interior materials of various vehicles such as automobiles and railway vehicles. DETAILED DESCRIPTION

[0014] The aqueous resin composition of the present invention contains a polycarbonate-modified acrylic resin and an aqueous medium. The polycarbonate-modified acrylic resin is a reaction product of a polycarbonate diol (A) having 1,4-butanediol as an essential raw material and an unsaturated monomer mixture (B). The unsaturated monomer mixture (B) contains methyl methacrylate, an unsaturated monomer (b1) having a hydroxyl group, an unsaturated monomer (b2) having a carboxyl group, and an unsaturated monomer (b3) having an alicyclic structure as essential components. The ratio of the unsaturated monomer (b3) in the unsaturated monomer mixture (B) is in the range of 3 to 60% by mass.

[0015] First, the polycarbonate diol (A) will be described. The polycarbonate diol (A) is a polycarbonate diol made from 1,4-butanediol as a raw material, and can be obtained, for example, by reacting 1,4-butanediol and other diol compounds with carbonate or phosgene.

[0016] As the above-mentioned other diol compounds, 1,3-propylene glycol, 1,2-propylene glycol, 2-methyl-1,3-propylene glycol, 2,2-dimethyl-1,3-propylene glycol, 2-butyl-2-ethyl-1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 1,5-pentanediol, 2,4-pentanediol, 2-methyl-1,3-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,5-hexanediol, 2-ethyl-1,3-hexanediol, etc. can be mentioned. From the aspect of better fragrance resistance, 1,3-propylene glycol, 2-methyl-1,3-propylene glycol, and 1,6-hexanediol are preferred, and 1,6-hexanediol is more preferred. It should be noted that these diol compounds can be used alone or in combination of two or more.

[0017] From the viewpoint of further improving the adhesion to the plastic substrate, the mass ratio of 1,4-butanediol to the other diol compound is preferably in the range of 30 / 70 to 90 / 10, and more preferably in the range of 50 / 50 to 90 / 10.

[0018] The number average molecular weight of the polycarbonate diol (A) is preferably in the range of 300 to 5,000, more preferably in the range of 700 to 3,000, from the viewpoint of achieving better adhesion to substrates and aroma resistance.

[0019] Next, the unsaturated monomer mixture (B) is described. The unsaturated monomer mixture (B) contains methyl methacrylate, an unsaturated monomer (b1) having a hydroxyl group, an unsaturated monomer (b2) having a carboxyl group, and an unsaturated monomer (b3) having an alicyclic structure as essential components, and the ratio of the unsaturated monomer (b3) is in the range of 3 to 60% by mass.

[0020] As the above-mentioned unsaturated monomer (b1) having a hydroxyl group, for example, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxy-n-butyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy-n-butyl (meth)acrylate, 3-hydroxy-n-butyl (meth)acrylate, 1,4-cyclohexanedimethanol mono(meth)acrylate, glycerol mono(meth)acrylate, polyoxyethylene mono(meth)acrylate, polyoxypropylene mono(meth)acrylate, polyoxybutylene mono(meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-(meth)acryloyloxyethyl-2-hydroxyethyl phthalate, polycaprolactone-modified hydroxyethyl mono(meth)acrylate, etc. can be cited. Among them, 2-hydroxyethyl (meth)acrylate is preferred from the perspective of the appearance, water-resistant adhesion, and fragrance resistance of the obtained coating film. It should be noted that these unsaturated monomers (b1) can be used alone or in combination of two or more.

[0021] It should be noted that in the present invention, "(meth)acrylic acid" refers to one or both of methacrylic acid and acrylic acid, "(meth)acrylate" refers to one or both of methacrylate and acrylate, and "(meth)acryloyl" refers to one or both of methacryloyl and acryloyl.

[0022] As the above-mentioned unsaturated monomer (b2) having a carboxyl group, for example, unsaturated monocarboxylic acids such as (meth) acrylic acid, crotonic acid, (meth) acrylic acid β-carboxyethyl ester, ω-carboxyl-polycaprolactone mono(meth)acrylate, succinic acid 2-(meth)acryloyloxyethyl ester, and hexahydrophthalic acid 2-(meth)acryloyloxyethyl ester can be cited; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid, or half esters of these unsaturated dicarboxylic acids, etc. Among them, (meth) acrylic acid is preferred from the perspective of better dispersibility in water. It should be noted that these unsaturated monomers (b2) can be used alone or in combination of two or more.

[0023] As the unsaturated monomer (b3) having an alicyclic structure, for example, cyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, 1,4-cyclohexanedimethanol mono(meth)acrylate, etc. can be cited. From the perspective of further improving adhesion and water-resistant adhesion, cyclohexyl (meth)acrylate is more preferred. It should be noted that these unsaturated monomers (b3) can be used alone or in combination of two or more.

[0024] The above-mentioned unsaturated monomer mixture (B) contains methyl methacrylate, unsaturated monomer (b1), unsaturated monomer (b2) and unsaturated monomer (b3) as essential components, but other unsaturated monomers (b4) may also be used. Examples of other unsaturated monomers (b4) include methyl acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, and tert-butyl (meth)acrylate. Cetyl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, benzyl (meth)acrylate; acrylamide, N,N-dimethyl (meth)acrylamide, (meth)acrylonitrile, 3-(meth)acryloyloxypropyl trimethoxysilane, N,N-dimethylaminoethyl (meth)acrylate, 2-(meth)acryloyloxyethyl acid phosphate, glycidyl (meth)acrylate, vinyl acetate, styrene, α-methylstyrene, p-methylstyrene, p-methoxystyrene, diacrylate compounds such as ethylene glycol diacrylate, etc. In addition, these unsaturated monomers may be used alone or in combination of two or more.

[0025] The ratio of methyl methacrylate in the unsaturated monomer mixture (B) is preferably in the range of 20 to 80% by mass, more preferably in the range of 40 to 70% by mass, from the viewpoint of further improving the aroma resistance of the obtained coating film.

[0026] The ratio of the unsaturated monomer (b1) in the unsaturated monomer mixture (B) is preferably in the range of 1 to 50% by mass, more preferably 10 to 40% by mass, from the viewpoint of further improving the aroma resistance of the obtained coating film.

[0027] The ratio of the unsaturated monomer (b2) in the unsaturated monomer mixture (B) is preferably in the range of 1 to 10% by mass, more preferably in the range of 2 to 5% by mass, from the viewpoint of further improving the water-resistant adhesion of the obtained coating film.

[0028] The ratio of the unsaturated monomer (b3) in the unsaturated monomer mixture (B) is in the range of 3 to 60% by mass, preferably in the range of 5 to 40% by mass, and more preferably in the range of 10 to 30% by mass, from the perspective of obtaining a coating film with better adhesion and water-resistant adhesion.

[0029] As a method for obtaining the polycarbonate-modified acrylic resin, a method of radically polymerizing the unsaturated monomer mixture (B) in the presence of the polycarbonate diol (A) and a solvent is preferred because it is simple.

[0030] The above-mentioned free radical polymerization method is a method of dissolving each monomer as a raw material in a solvent and performing a polymerization reaction in the presence of a polymerization initiator. As the solvent that can be used at this time, for example, aromatic hydrocarbon compounds such as toluene and xylene can be cited; alicyclic hydrocarbon compounds such as cyclohexane, methylcyclohexane, and ethylcyclohexane; ketone compounds such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester compounds such as ethyl acetate, n-butyl acetate, isobutyl acetate, and propylene glycol monomethyl ether acetate; alcohol compounds such as n-butanol, isopropanol, and cyclohexanol; glycol compounds such as ethylene glycol monobutyl ether, propylene glycol monomethyl ether, and diethylene glycol dimethyl ether; aliphatic hydrocarbon compounds such as heptane, hexane, octane, and mineral turpentine, etc. Among them, from the aspect that it can be directly used as an aqueous medium contained in the water-based resin composition of the present invention, it is preferred to use a water-miscible organic solvent. It should be noted that these solvents can be used alone or in combination of two or more.

[0031] Examples of the polymerization initiator include ketone peroxide compounds such as cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, and methylcyclohexanone peroxide; 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, n-butyl-4,4-bis(tert-butylperoxy)valerate, 2,2-bis(4,4-di-tert-butylperoxycyclohexyl) ester; Peroxyketal compounds such as 2,2-bis(4,4-di-tert-amylperoxycyclohexyl)propane, 2,2-bis(4,4-di-tert-hexylperoxycyclohexyl)propane, 2,2-bis(4,4-di-tert-octylperoxycyclohexyl)propane, and 2,2-bis(4,4-dicumylperoxycyclohexyl)propane; and hydroperoxide compounds such as cumene hydroperoxide and 2,5-dimethylhexane-2,5-dihydroperoxide. ; dialkyl peroxide compounds such as 1,3-bis(tert-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, diisopropylbenzene peroxide, tert-butylisopropylbenzene peroxide, di-tert-butyl peroxide; diacyl peroxide compounds such as decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide; bis(tert-butylcyclohexyl) peroxydicarbonate esters; organic peroxides such as peroxyester compounds such as tert-butyl peroxy-2-ethylhexanoate, tert-amyl peroxy-2-ethylhexanoate, tert-butyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoyl peroxide)hexane, and azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methyl)butyronitrile and 1,1'-azobis(cyclohexane-1-carbonitrile). Added new initiator types.

[0032] In addition, from the perspective of further improving the water-resistant adhesion, chemical resistance and fragrance resistance of the resulting coating film, the mass ratio [(A) / (B)] of the polycarbonate diol (A) to the unsaturated monomer mixture (B) is preferably in the range of 2 / 100 to 60 / 100, preferably in the range of 3 / 100 to 50 / 100, and more preferably in the range of 5 / 100 to 30 / 100.

[0033] The hydroxyl value of the polycarbonate-modified acrylic resin is preferably in the range of 20 to 150 mgKOH / g, more preferably in the range of 60 to 150 mgKOH / g, from the viewpoint of further improving the aroma resistance of the obtained coating film.

[0034] The acid value of the polycarbonate-modified acrylic resin is preferably in the range of 5 to 60 mgKOH / g, more preferably in the range of 10 to 40 mgKOH / g, from the viewpoint of further improving the storage stability of the aqueous resin composition and the aroma resistance of the resulting coating film.

[0035] The weight average molecular weight (Mw) of the polycarbonate-modified acrylic resin is preferably in the range of 2,000 to 50,000, more preferably in the range of 4,000 to 30,000, from the viewpoint of further improving the water-resistant adhesion and aroma resistance of the obtained coating film.

[0036] The average molecular weight in the present invention is a value obtained by measuring with gel permeation chromatography (hereinafter, abbreviated as "GPC") and converting it into polystyrene.

[0037] As the aqueous medium, for example, water, a hydrophilic organic solvent, and a mixture thereof can be cited. As the hydrophilic organic solvent, a water-miscible organic solvent that is miscible with water is preferred, and an organic solvent having a solubility in water (the number of grams of the organic solvent dissolved in 100 g of water) of 3 g or more at 25° C. is preferred. As these water miscible organic solvents, for example, alcohol solvents such as methanol, ethanol, propanol, butanol, 3-methoxybutanol, and 3-methyl-3-methoxybutanol can be cited; ketone solvents such as acetone and methyl ethyl ketone; glycol ether solvents such as ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol dimethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, and dipropylene glycol dimethyl ether. These water miscible organic solvents can be used alone or in combination of two or more.

[0038] The aqueous resin composition of the present invention contains a polycarbonate-modified acrylic resin and an aqueous medium. The polycarbonate-modified acrylic resin obtained by the above method is preferably dissolved or dispersed in the aqueous medium, and more preferably in the form of a dispersion.

[0039] As a method for dissolving or dispersing the polycarbonate-modified acrylic resin in the aqueous medium, a method of mixing a substance obtained by neutralizing the acid group of the polycarbonate-modified acrylic resin with a basic compound with the aqueous medium is preferred.

[0040] As the above-mentioned alkaline compound, for example, monoalkanolamines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, butylamine, dibutylamine, tributylamine, N,N-dimethylethanolamine, 2-aminoethanol, diethanolamine, diisopropanolamine, dibutanolamine and other organic amines; inorganic alkaline compounds such as ammonia, sodium hydroxide, potassium hydroxide; quaternary ammonium hydroxides of tetramethylammonium hydroxide, tetra-n-butylammonium hydroxide, trimethylbenzylammonium hydroxide, etc. Among them, organic amines and ammonia (which may be aqueous ammonia) are preferably used. It should be noted that these alkaline compounds can be used alone or in combination of two or more.

[0041] The amount of the basic compound used is preferably such that the neutralization rate of the carboxyl groups of the polycarbonate-modified acrylic resin is within a range of 50 to 100% from the viewpoint of further improving the storage stability of the aqueous resin composition.

[0042] The coating material of the present invention contains the aqueous resin composition of the present invention, and preferably contains a curing agent from the viewpoint of further improving the physical properties of the obtained coating film.

[0043] As the above-mentioned curing agent, for example, polyisocyanate compounds, amino resins, epoxy compounds, oxazoline compounds, carbodiimide compounds, etc. can be cited. From the aspect that the water-resistant adhesion and aromatic resistance of the obtained coating film are further improved, polyisocyanate compounds are preferred. It should be noted that, it can be used alone or in combination of two or more.

[0044] Examples of the polyisocyanate compound include aromatic diisocyanate compounds such as tolylene diisocyanate, diphenylmethane diisocyanate, meta-xylylene diisocyanate, and meta-phenylenebis(dimethylmethylene) diisocyanate; and aliphatic or alicyclic diisocyanate compounds such as hexamethylene diisocyanate, lysine diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 2-methyl-1,3-diisocyanatocyclohexane, 2-methyl-1,5-diisocyanatocyclohexane, 4,4′-dicyclohexylmethane diisocyanate and isophorone diisocyanate.

[0045] In addition, as the above-mentioned polyisocyanate compound, it is also possible to use: a prepolymer having an isocyanate group obtained by allowing the above-mentioned diisocyanate compound to undergo an addition reaction with a polyol; a compound having an isocyanurate ring obtained by cyclotrimerizing the above-mentioned diisocyanate compound; a polyisocyanate compound having a urea bond or a biuret bond obtained by allowing the above-mentioned diisocyanate compound to react with water; a homopolymer of an acrylic monomer having an isocyanate group such as (meth) acrylate 2-isocyanatoethyl, 3-isopropenyl-α,α-dimethylbenzyl isocyanate, (meth) acryloyl isocyanate, etc.; a copolymer having an isocyanate group obtained by copolymerizing the above-mentioned acrylic monomer having an isocyanate group with other acrylic monomers, vinyl ester compounds, vinyl ether compounds, aromatic vinyl monomers, fluoroolefins, etc.

[0046] The polyisocyanate compound is preferably a water-dispersible polyisocyanate obtained by modifying the polyisocyanate compound, because the polyisocyanate compound has excellent stability and curability when mixed with the aqueous resin composition of the present invention and has a high degree of freedom in pot life.

[0047] The above-mentioned polyisocyanate compounds may be used alone or in combination of two or more.

[0048] The amount of the polyisocyanate compound to be added is preferably in the range of 0.5 to 2.0, more preferably in the range of 0.8 to 1.5, in terms of obtaining a high-strength coating film, in terms of the equivalent ratio (isocyanate group / hydroxyl group) of the isocyanate group in the polyisocyanate compound to the hydroxyl group in the polycarbonate-modified acrylic resin.

[0049] It should be noted that, in order to promote the reaction, the above-mentioned urethanization reaction can also be carried out in the presence of a urethanization catalyst. Examples of the above-mentioned urethanization catalyst include amine compounds such as triethylamine, dibutyltin dioctoate, dibutyltin dilaurate, dioctyltin dilaurate, octyltin trilaurate, dioctyltin dineodecanoate, dibutyltin diacetate, dioctyltin diacetate, tin dioctoate and other organic tin compounds, and organic metal compounds such as zinc octoate (zinc 2-ethylhexanoate).

[0050] The coating of the present invention contains the water-based resin composition of the present invention and a curing agent. As other compounding agents, additives such as defoamers, viscosity modifiers, light-resistant stabilizers, weather-resistant stabilizers, heat-resistant stabilizers, ultraviolet absorbers, antioxidants, leveling agents, and pigment dispersants can be used. In addition, pigments such as titanium oxide, calcium carbonate, aluminum powder, copper powder, mica powder, iron oxide, carbon black, phthalocyanine blue, toluidine red, perylene, quinacridone, and benzidine yellow can also be used.

[0051] The coating of the present invention has high adhesion to plastic substrates and can therefore be suitably used as a coating for coating various plastic molded products. Examples of plastic molded products that can be coated with the coating of the present invention include housings of electronic devices such as mobile phones, smart phones, tablet terminals, personal computers, digital cameras, and game consoles; housings of household electrical appliances such as televisions, refrigerators, washing machines, and air conditioners; and interior materials for various vehicles such as automobiles and railway vehicles.

[0052] As the coating method of the coating of the present invention, for example, there can be mentioned methods such as sprayer, applicator, rod coater, gravure coater, roll coater, comma coater, blade coater, air knife coater, curtain coater, kiss coater, spray coater, wheel coater, spin coater, dipping, screen printing, etc. In addition, as a method for forming a coating film after coating, there can be mentioned a method of drying at a range of room temperature to 120°C.

[0053] Example

[0054] The present invention is described in more detail below with reference to specific examples. It should be noted that the hydroxyl value of the polycarbonate-modified acrylic resin of the present invention is a value measured based on JIS test method K0070-1992. The particle size is measured using Nanotrac UPA-EX150 manufactured by Nikkiso Co., Ltd. In addition, the average molecular weight is measured under the following GPC measurement conditions.

[0055] [GPC measurement conditions]

[0056] Measuring device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation)

[0057] Column: The following columns manufactured by Tosoh Corporation were connected in series and used.

[0058] "TSKgel G5000" (7.8mm I.D. × 30cm) × 1 piece

[0059] "TSKgel G4000" (7.8mm I.D. × 30cm) × 1 piece

[0060] "TSKgel G3000" (7.8mm I.D. × 30cm) × 1 piece

[0061] "TSKgel G2000" (7.8mm I.D. × 30cm) × 1 piece

[0062] Detector: RI (differential refractometer)

[0063] Column temperature: 40°C

[0064] Eluent: Tetrahydrofuran (THF)

[0065] Flow rate: 1.0mL / min

[0066] Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 4 mg / mL)

[0067] Standard sample: The following monodisperse polystyrene was used to prepare a calibration curve.

[0068] (monodisperse polystyrene)

[0069] "TSKgel Standard Polystyrene A-500" manufactured by Tosoh Corporation

[0070] "TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Corporation

[0071] "TSKgel Standard Polystyrene A-2500" manufactured by Tosoh Corporation

[0072] "TSKgel Standard Polystyrene A-5000" manufactured by Tosoh Corporation

[0073] "TSKgel Standard Polystyrene F-1" manufactured by Tosoh Corporation

[0074] "TSKgel Standard Polystyrene F-2" manufactured by Tosoh Corporation

[0075] "TSKgel Standard Polystyrene F-4" manufactured by Tosoh Corporation

[0076] "TSKgel Standard Polystyrene F-10" manufactured by Tosoh Corporation

[0077] "TSKgel Standard Polystyrene F-20" manufactured by Tosoh Corporation

[0078] "TSKgel Standard Polystyrene F-40" manufactured by Tosoh Corporation

[0079] "TSKgel Standard Polystyrene F-80" manufactured by Tosoh Corporation

[0080] "TSKgel Standard Polystyrene F-128" manufactured by Tosoh Corporation

[0081] "TSKgel Standard Polystyrene F-288" manufactured by Tosoh Corporation

[0082] "TSKgel Standard Polystyrene F-550" manufactured by Tosoh Corporation

[0083] (Example 1: Synthesis of aqueous resin composition (1))

[0084] In a flask equipped with a cooling tube, a thermometer, a dropping funnel, and a stirrer, 60 parts by mass of a polycarbonate diol ("DURANOL G4672" manufactured by Asahi Kasei Chemicals Co., Ltd., number average molecular weight 2000; hereinafter referred to as "polycarbonate diol (A-1)") containing 1,4-butanediol as an essential raw material and 144.7 parts by mass of diethylene glycol dimethyl ether were added, and the internal temperature was raised to 135° C. Next, a mixture of 45 parts by mass of cyclohexyl methacrylate, 259.0 parts by mass of methyl methacrylate, 9.5 parts by mass of butyl acrylate, 125.2 parts by mass of 2-hydroxyethyl methacrylate, and 17.5 parts by mass of tert-butyl peroxy-2-ethylhexanoate was added dropwise over 3 hours. Next, a mixture of 15 parts by mass of cyclohexyl methacrylate, 86.3 parts by mass of methyl methacrylate, 4.0 parts by mass of butyl acrylate, 41.8 parts by mass of 2-hydroxyethyl methacrylate, 15.4 parts by mass of acrylic acid and 15.4 parts by mass of tert-butyl peroxy-2-ethylhexanoate was added dropwise over 1 hour. After the addition was completed, the mixture was stirred at the same temperature for 2 hours and then cooled to 95°C. 15.3 parts by mass of dimethylethanolamine was added thereto and stirred for 30 minutes. 686.9 parts by mass of ion exchange water was further added for water dispersion to obtain an aqueous resin composition (1). The non-volatile content of the aqueous resin composition (1) was 46.3% and the weight average molecular weight (Mw) was 12,000.

[0085] (Example 2: Synthesis of Aqueous Resin Composition (2))

[0086] In a flask equipped with a cooling tube, a thermometer, a dropping funnel, and a stirrer, 60 parts by mass of polycarbonate diol (A-1) and 144.7 parts by mass of diethylene glycol dimethyl ether were added, and the internal temperature was raised to 135°C. Next, a mixture of 90 parts by mass of cyclohexyl methacrylate, 220.7 parts by mass of methyl methacrylate, 2.7 parts by mass of butyl acrylate, 125.1 parts by mass of 2-hydroxyethyl methacrylate, and 17.5 parts by mass of tert-butyl peroxy-2-ethylhexanoate was added dropwise over 3 hours. Next, a mixture of 30 parts by mass of cyclohexyl methacrylate, 73.6 parts by mass of methyl methacrylate, 0.9 parts by mass of butyl acrylate, 41.7 parts by mass of 2-hydroxyethyl methacrylate, 15.6 parts by mass of acrylic acid, and 15.4 parts by mass of tert-butyl peroxy-2-ethylhexanoate was added dropwise over 1 hour. After the addition was completed, the mixture was stirred at the same temperature for 2 hours, and then cooled to 95°C. 15.3 parts by mass of dimethylethanolamine was added thereto, followed by stirring for 30 minutes. 686.9 parts by mass of ion exchange water was further added for water dispersion, thereby obtaining an aqueous resin composition (2). The aqueous resin composition (2) had a nonvolatile content of 46.2% and a weight average molecular weight (Mw) of 13,000.

[0087] (Example 3: Synthesis of aqueous resin composition (3))

[0088] In a flask equipped with a cooling tube, a thermometer, a dropping funnel, and a stirrer, 60 parts by mass of a polycarbonate diol ("DURANOL T4671" manufactured by Asahi Kasei Chemicals Co., Ltd., number average molecular weight 1000; hereinafter abbreviated as "polycarbonate diol (A-2)") containing 1,4-butanediol as an essential raw material and 144.7 parts by mass of diethylene glycol dimethyl ether were added, and the internal temperature was raised to 135° C. Next, a mixture of 90 parts by mass of cyclohexyl methacrylate, 220.7 parts by mass of methyl methacrylate, 2.7 parts by mass of butyl acrylate, 125.1 parts by mass of 2-hydroxyethyl methacrylate, and 17.5 parts by mass of tert-butyl peroxy-2-ethylhexanoate was added dropwise over 3 hours. Next, a mixture of 30 parts by mass of cyclohexyl methacrylate, 73.6 parts by mass of methyl methacrylate, 0.9 parts by mass of butyl acrylate, 41.7 parts by mass of 2-hydroxyethyl methacrylate, 15.6 parts by mass of acrylic acid and 15.4 parts by mass of tert-butyl peroxy-2-ethylhexanoate was added dropwise over 1 hour. After the addition was completed, the mixture was stirred at the same temperature for 2 hours and then cooled to 95°C. 15.3 parts by mass of dimethylethanolamine was added thereto and stirred for 30 minutes. 686.9 parts by mass of ion exchange water was further added for water dispersion to obtain an aqueous resin composition (3). The non-volatile content of the aqueous resin composition (3) was 46.0% and the weight average molecular weight (Mw) was 13,000.

[0089] (Example 4: Synthesis of aqueous resin composition (4))

[0090] In a flask equipped with a cooling tube, a thermometer, a dropping funnel, and a stirrer, 60 parts by mass of a polycarbonate diol ("DURANOL G3452" manufactured by Asahi Kasei Chemicals Co., Ltd., number average molecular weight 2000; hereinafter referred to as "polycarbonate diol (A-3)") containing 1,4-butanediol as an essential raw material and 144.7 parts by mass of diethylene glycol dimethyl ether were added, and the internal temperature was raised to 135° C. Next, a mixture of 90 parts by mass of cyclohexyl methacrylate, 220.7 parts by mass of methyl methacrylate, 2.7 parts by mass of butyl acrylate, 125.1 parts by mass of 2-hydroxyethyl methacrylate, and 17.5 parts by mass of tert-butyl peroxy-2-ethylhexanoate was added dropwise over 3 hours. Next, a mixture of 30 parts by mass of cyclohexyl methacrylate, 73.6 parts by mass of methyl methacrylate, 0.9 parts by mass of butyl acrylate, 41.7 parts by mass of 2-hydroxyethyl methacrylate, 15.6 parts by mass of acrylic acid and 15.4 parts by mass of tert-butyl peroxy-2-ethylhexanoate was added dropwise over 1 hour. After the addition was completed, the mixture was stirred at the same temperature for 2 hours and then cooled to 95°C. 15.3 parts by mass of dimethylethanolamine was added thereto and stirred for 30 minutes. 686.9 parts by mass of ion exchange water was further added for water dispersion to obtain an aqueous resin composition (4). The aqueous resin composition (4) had a non-volatile content of 45.9% and a weight average molecular weight (Mw) of 12,000.

[0091] (Example 5: Synthesis of Aqueous Resin Composition (5))

[0092] In a flask equipped with a cooling tube, a thermometer, a dropping funnel, and a stirrer, 60 parts by mass of polycarbonate diol (A-1) and 144.7 parts by mass of diethylene glycol dimethyl ether were added, and the internal temperature was raised to 135°C. Next, a mixture of 90 parts by mass of cyclohexyl methacrylate, 200.3 parts by mass of methyl methacrylate, 1.8 parts by mass of butyl acrylate, 146.3 parts by mass of 2-hydroxyethyl methacrylate, and 17.5 parts by mass of tert-butyl peroxy-2-ethylhexanoate was added dropwise over 3 hours. Next, a mixture of 30 parts by mass of cyclohexyl methacrylate, 66.8 parts by mass of methyl methacrylate, 0.6 parts by mass of butyl acrylate, 48.8 parts by mass of 2-hydroxyethyl methacrylate, 15.6 parts by mass of acrylic acid, and 15.4 parts by mass of tert-butyl peroxy-2-ethylhexanoate was added dropwise over 1 hour. After the addition was completed, the mixture was stirred at the same temperature for 2 hours, and then cooled to 95°C. 15.3 parts by mass of dimethylethanolamine was added thereto, followed by stirring for 30 minutes. 686.9 parts by mass of ion exchange water was further added for water dispersion, thereby obtaining an aqueous resin composition (5). The aqueous resin composition (5) had a nonvolatile content of 44.5% and a weight average molecular weight (Mw) of 13,000.

[0093] (Example 6: Synthesis of Aqueous Resin Composition (6))

[0094] In a flask equipped with a cooling tube, a thermometer, a dropping funnel, and a stirrer, 120 parts by mass of polycarbonate diol (A-1) and 159.5 parts by mass of diethylene glycol dimethyl ether were added, and the internal temperature was raised to 135°C. Next, a mixture of 90 parts by mass of cyclohexyl methacrylate, 220.7 parts by mass of methyl methacrylate, 2.7 parts by mass of butyl acrylate, 125.1 parts by mass of 2-hydroxyethyl methacrylate, and 17.5 parts by mass of tert-butyl peroxy-2-ethylhexanoate was added dropwise over 3 hours. Next, a mixture of 30 parts by mass of cyclohexyl methacrylate, 73.6 parts by mass of methyl methacrylate, 0.9 parts by mass of butyl acrylate, 41.7 parts by mass of 2-hydroxyethyl methacrylate, 15.6 parts by mass of acrylic acid, and 15.4 parts by mass of tert-butyl peroxy-2-ethylhexanoate was added dropwise over 1 hour. After the addition was completed, the mixture was stirred at the same temperature for 2 hours, and then cooled to 95°C. 15.3 parts by mass of dimethylethanolamine was added thereto, followed by stirring for 30 minutes. 746.9 parts by mass of ion exchange water was further added for water dispersion to obtain an aqueous resin composition (5). The aqueous resin composition (5) had a nonvolatile content of 44.3% and a weight average molecular weight (Mw) of 12,000.

[0095] (Comparative Example 1: Synthesis of Aqueous Resin Composition (R1))

[0096] 30 parts by mass of polycarbonate diol (A-1) and 137.2 parts by mass of diethylene glycol dimethyl ether were added to a flask equipped with a cooling tube, a thermometer, a dropping funnel, and a stirrer, and the internal temperature was raised to 135°C. Next, a mixture of 296.7 parts by mass of methyl methacrylate, 16.5 parts by mass of butyl acrylate, 125.2 parts by mass of 2-hydroxyethyl methacrylate, and 17.5 parts by mass of tert-butyl peroxy-2-ethylhexanoate was added dropwise over 3 hours. Next, a mixture of 98.9 parts by mass of methyl methacrylate, 5.5 parts by mass of butyl acrylate, 41.8 parts by mass of 2-hydroxyethyl methacrylate, 15.4 parts by mass of acrylic acid, and 15.4 parts by mass of tert-butyl peroxy-2-ethylhexanoate was added dropwise over 1 hour. After the addition was completed, the mixture was stirred at the same temperature for 2 hours, and then cooled to 95°C. 15.3 parts by mass of dimethylethanolamine was added thereto, and then stirred for 30 minutes. Furthermore, 656.2 parts by mass of ion exchange water was added to disperse the mixture in water, thereby obtaining an aqueous resin composition (R1). The aqueous resin composition (R1) had a nonvolatile content of 43.9% and a weight average molecular weight (Mw) of 12,000.

[0097] (Comparative Example 2: Synthesis of Aqueous Resin Composition (R2))

[0098] 30 parts by mass of polycarbonate diol (A-3) and 137.2 parts by mass of diethylene glycol dimethyl ether were added to a flask equipped with a cooling tube, a thermometer, a dropping funnel, and a stirrer, and the internal temperature was raised to 135°C. Next, a mixture of 296.6 parts by mass of methyl methacrylate, 16.7 parts by mass of butyl acrylate, 125.1 parts by mass of 2-hydroxyethyl methacrylate, and 17.5 parts by mass of tert-butyl peroxy-2-ethylhexanoate was added dropwise over 3 hours. Next, a mixture of 98.9 parts by mass of methyl methacrylate, 5.6 parts by mass of butyl acrylate, 41.7 parts by mass of 2-hydroxyethyl methacrylate, 15.6 parts by mass of acrylic acid, and 15.4 parts by mass of tert-butyl peroxy-2-ethylhexanoate was added dropwise over 1 hour. After the addition was completed, the mixture was stirred at the same temperature for 2 hours, and then cooled to 95°C. 15.3 parts by mass of dimethylethanolamine was added thereto, and then stirred for 30 minutes. Furthermore, 656.2 parts by mass of ion exchange water was added to disperse the mixture in water, thereby obtaining an aqueous resin composition (R2). The aqueous resin composition (R2) had a nonvolatile content of 43.9% and a weight average molecular weight (Mw) of 12,000.

[0099] (Comparative Example 3: Synthesis of Aqueous Resin Composition (R3))

[0100] 60 parts by mass of polycarbonate diol ("DURANOL T5652" manufactured by Asahikasei Chemicals Co., Ltd., number average molecular weight 2000; hereinafter referred to as "polycarbonate diol (RA-1)") and 144.7 parts by mass of diethylene glycol dimethyl ether were added to a flask equipped with a cooling tube, a thermometer, a dropping funnel and a stirrer, and the internal temperature was raised to 135° C. Then, a mixture of 90 parts by mass of cyclohexyl methacrylate, 220.7 parts by mass of methyl methacrylate, 2.7 parts by mass of butyl acrylate, 125.1 parts by mass of 2-hydroxyethyl methacrylate and 17.5 parts by mass of tert-butyl peroxy-2-ethylhexanoate was added dropwise over 3 hours. Next, a mixture of 30 parts by mass of cyclohexyl methacrylate, 73.6 parts by mass of methyl methacrylate, 0.9 parts by mass of butyl acrylate, 41.7 parts by mass of 2-hydroxyethyl methacrylate, 15.6 parts by mass of acrylic acid and 15.4 parts by mass of tert-butyl peroxy-2-ethylhexanoate was added dropwise over 1 hour. After the addition was completed, the mixture was stirred at the same temperature for 2 hours and then cooled to 95°C. After 15.3 parts by mass of dimethylethanolamine was added thereto, the mixture was stirred for 30 minutes. Further, 686.9 parts by mass of ion exchange water was added for water dispersion to obtain an aqueous resin composition (R3). The non-volatile component of the aqueous resin composition (R4) was 45.1%, and the weight average molecular weight (Mw) was 13,000.

[0101] (Comparative Example 5: Synthesis of Aqueous Resin Composition (R4))

[0102] 60 parts by mass of polycarbonate diol ("DURANOL T5650J" manufactured by Asahikasei Chemicals Co., Ltd., number average molecular weight 800; hereinafter referred to as "polycarbonate diol (RA-2)") and 144.7 parts by mass of diethylene glycol dimethyl ether were added to a flask equipped with a cooling tube, a thermometer, a dropping funnel and a stirrer, and the internal temperature was raised to 135° C. Next, a mixture of 90 parts by mass of cyclohexyl methacrylate, 220.7 parts by mass of methyl methacrylate, 2.7 parts by mass of butyl acrylate, 125.1 parts by mass of 2-hydroxyethyl methacrylate and 17.5 parts by mass of tert-butyl peroxy-2-ethylhexanoate was added dropwise over 3 hours. Next, a mixture of 30 parts by mass of cyclohexyl methacrylate, 73.6 parts by mass of methyl methacrylate, 0.9 parts by mass of butyl acrylate, 41.7 parts by mass of 2-hydroxyethyl methacrylate, 15.6 parts by mass of acrylic acid and 15.4 parts by mass of tert-butyl peroxy-2-ethylhexanoate was added dropwise over 1 hour. After the addition was completed, the mixture was stirred at the same temperature for 2 hours and then cooled to 95°C. After 15.3 parts by mass of dimethylethanolamine was added thereto, the mixture was stirred for 30 minutes. 686.9 parts by mass of ion exchange water was further added for water dispersion to obtain an aqueous resin composition (R5). The non-volatile component of the aqueous resin composition (R5) was 45.6%, and the weight average molecular weight (Mw) was 12,000.

[0103] Table 1 shows the compositions and evaluation results of the aqueous resin compositions (1) to (6) obtained above.

[0104] [Table 1]

[0105]

[0106] The abbreviations in Tables 1 and 2 are the following.

[0107] MMA: Methyl Methacrylate

[0108] HEMA: 2-Hydroxyethyl Methacrylate

[0109] AA: Acrylic acid

[0110] CHMA: Cyclohexyl methacrylate

[0111] BA: Butyl acrylate

[0112] Table 2 shows the compositions of the comparative aqueous resin compositions (R1) to (R4) obtained above.

[0113] [Table 2]

[0114]

[0115] (Examples 7 to 12: Preparation and evaluation of coatings (1) to (6))

[0116] [Preparation of water-based coatings]

[0117] The aqueous resin composition obtained above and a curing agent ("Burnock DNW-5500" manufactured by DIC Corporation, a water-dispersible polyisocyanate) were mixed. It should be noted that the equivalent of the hydroxyl group in the polycarbonate-modified acrylic resin and the equivalent of the isocyanate group in the curing agent were set to a ratio of 1.0:1.2. Next, the aqueous coating was prepared by diluting with ion-exchanged water until the viscosity was about 13 seconds (23°C) in the "Viscosity Cup NK-2" manufactured by ANEST IWATA Corporation.

[0118] [Preparation of Cured Coating Film X for Evaluation]

[0119] The aqueous coating obtained above was spray-coated on an ABS (acrylonitrile-butadiene-styrene copolymer) substrate (50 mm×70 mm×1 mm) so that the film thickness after drying was about 25 μm, and then dried at 80° C. for 30 minutes in a dryer and then dried at 25° C. for 7 days to prepare a cured coating film X for evaluation.

[0120] [Preparation of Cured Coating Film Y for Evaluation]

[0121] The water-based coating obtained above was spray-coated on a PC (polycarbonate) substrate (50 mm×70 mm×1 mm) so that the film thickness after drying was about 25 μm, and then dried at 80°C for 30 minutes in a dryer and then at 25°C for 7 days to prepare a cured coating film Y for evaluation.

[0122] [Evaluation of Adhesion]

[0123] A 1 mm wide cut was made in the cured coating film for evaluation using a cutter so that the number of squares was 100. Then, a transparent tape was attached so as to cover all the squares, and the tape was quickly peeled off four times. The adhesion was evaluated according to the number of squares remaining after adhesion according to the following criteria.

[0124] ◎:100

[0125] ○: 99-90

[0126] △: 89-70

[0127] ×: Less than 69

[0128] [Evaluation of water-resistant adhesion]

[0129] The cured coating film for evaluation obtained above was immersed in water at 40° C. for 240 hours, and then the same operation as the above-mentioned adhesion evaluation was performed to evaluate water-resistant adhesion according to the following criteria.

[0130] ◎:100

[0131] ○: 99-90

[0132] △: 89-70

[0133] ×: Less than 69

[0134] [Evaluation of aroma resistance]

[0135] A fragrance (Royal Pine air freshener) cut into 15 mm × 15 mm pieces was placed on the cured coating film X for evaluation obtained above, and dried at 74° C. for 4 hours while applying a load with a 500 g weight. The fragrance was then removed by hand, the appearance was visually observed, and the fragrance resistance was evaluated according to the following criteria.

[0136] 5: No trace or a part with thin trace

[0137] 4: There are thin traces on the whole

[0138] 3: There are traces

[0139] 2: The fragrance is removed, but the base of the substrate is exposed

[0140] 1: Fragrance cannot be removed from the substrate in the bonded state

[0141] (Comparative Examples 5 to 8: Preparation and Evaluation of Water-Based Coatings (R1) to (R4))

[0142] After preparing a water-based coating material in the same manner as in the examples, a coating film for evaluation was produced, and various evaluations were performed.

[0143] Table 3 shows the evaluation results of the water-based coating materials (1) to (6) obtained above.

[0144] [Table 3]

[0145]

[0146] Table 4 shows the evaluation results of the coating materials (R1) to (R4) obtained above.

[0147] [Table 4]

[0148]

[0149] It was confirmed that the cured coating films obtained from Examples 1 to 6, which are the aqueous resin compositions of the present invention, were excellent in adhesion, water-resistant adhesion, and fragrance resistance (Examples 7 to 12).

[0150] On the other hand, Comparative Examples 1 and 2 are examples in which the unsaturated monomer mixture (B) does not contain the unsaturated monomer (b3) having an alicyclic structure, and it was confirmed that the obtained coating films had poor adhesion and water-resistant adhesion (Comparative Examples 5 and 6).

[0151] Comparative Examples 3 and 4 are examples in which polycarbonate diol containing 1,4-butanediol as an essential raw material was not used, and it was confirmed that the obtained cured coating films had poor aroma resistance (Comparative Examples 7 and 8).

Claims

1. An aqueous resin composition, characterized in that The invention relates to a polycarbonate-modified acrylic resin and an aqueous medium, wherein the polycarbonate-modified acrylic resin is obtained by subjecting an unsaturated monomer mixture B to a free radical reaction in the presence of a polycarbonate diol A having 1,4-butanediol as an essential raw material and a solvent, wherein the unsaturated monomer mixture B contains methyl methacrylate, an unsaturated monomer b1 having a hydroxyl group, an unsaturated monomer b2 having a carboxyl group, and an unsaturated monomer b3 having an alicyclic structure as essential components, The ratio of methyl methacrylate in the unsaturated monomer mixture B is in the range of 20 mass % to 80 mass %, the ratio of the unsaturated monomer b2 is in the range of 2 mass % to 10 mass %, and the ratio of the unsaturated monomer b3 is in the range of 3 mass % to 60 mass %.

2. The aqueous resin composition according to claim 1, wherein The mass ratio A / B of the polycarbonate diol A to the unsaturated monomer mixture B is in the range of 2 / 100 to 60 / 100.

3. The aqueous resin composition according to claim 1, wherein The ratio of the unsaturated monomer b1 in the unsaturated monomer mixture B is in the range of 1% by mass to 50% by mass.

4. The aqueous resin composition according to claim 1, wherein The unsaturated monomer b3 is cyclohexyl (meth)acrylate.

5. A water-based paint, characterized in that: The invention comprises the aqueous resin composition according to any one of claims 1 to 4 and a curing agent.

6. A plastic molded product, characterized in that: The invention is coated with the water-based paint according to claim 5.

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