Active energy ray-curable water-based resin composition, active energy ray-curable water-based paint, and article coated with the paint

Abstract

The active energy ray-curable water-based resin composition comprises: a reaction product (X) of an acrylic polymer (A) having a hydroxyl group and a urethane (meth) acrylate (B) having an isocyanate group, the urethane (meth) acrylate (B) having a carboxyl group and two or more (meth) acryloyl groups, and a water-based medium (Y). The active energy ray-curable water-based resin composition can be used for an active energy ray-curable water-based coating film, which can form a cured coating film having excellent adhesion, warm water resistance, and chemical resistance, and the coating can be applied to various articles.

Description

[Technical field]

[0001] The present invention relates to an active energy ray-curable water-based resin composition, an active energy ray-curable water-based paint, and a product coated with the paint. [Background Technology]

[0002] In view of the fact that there is almost no thermal history and excellent hardness and scratching performance of coating substrate, active energy ray curing type composition is used as the hard coating agent of the plastic substrate for household appliances, mobile phones etc. An example of active energy ray curing type composition is the active energy ray curing type composition containing the following (active energy ray curing type composition of solvent type): polymer with polymerizable unsaturated double bond (such as acryloyl acrylate (acryl acrylate) etc.), polymer without unsaturated double bond (such as polymerizable acrylic resin etc.), polymerizable monomer, and organic solvent as diluent. For example, when active energy ray curing type composition is used as the coating for spraying, coating needs to contain up to 50 mass % to 90 mass % organic solvent. Therefore, when forming cured coating film on substrate surface such as plastic etc. by using active energy ray curing type coating containing this resin combination, there is the problem that working environment deteriorates due to the volatilization of the organic solvent in coating. The organic solvent of volatilization also causes air pollution.

[0003] Under such circumstances, a production method has been proposed, which involves neutralizing a specific urethane acrylate-modified polyacrylate resin by adding an alkaline solution to produce an anionic ultraviolet-curable resin (for example, see Patent Document 1). However, the cured coating film of the resin produced by this production method has unsatisfactory adhesion, warm water resistance, and chemical resistance.

[0004] Therefore, there is a need for an active energy ray-curable aqueous resin composition that can produce a cured coating film having excellent adhesion, warm water resistance, and chemical resistance.

[0005] [Citation List]

[0006] [Patent Document]

[0007] PA236039C

[0008] [Patent Document 1]

[0009] Chinese Patent Application Publication No. CN109942772A [Summary of the invention]

[0010] [Technical Problem]

[0011] An object to be solved by the present invention is to provide an active energy ray-curable water-based resin composition that can produce a cured coating film having excellent adhesion, warm water resistance, and chemical resistance, an active energy ray-curable water-based paint containing the composition, and an article coated with the paint.

[0012] [Solution to the problem]

[0013] As a result of repeated and intensive studies to solve this problem, the inventors of the present invention discovered that this problem is solved by an active energy ray-curable aqueous resin composition comprising a reaction product of an acrylic polymer having a hydroxyl group and a specific urethane acrylate having an isocyanate group, and an aqueous medium, thereby completing the present invention.

[0014] That is, the present invention relates to an active energy ray-curable water-based resin composition, comprising: a reaction product (X) of an acrylic polymer (A) having a hydroxyl group and a urethane (meth)acrylate (B) having an isocyanate group, and an aqueous medium (Y), wherein the urethane (meth)acrylate (B) has a carboxyl group and two or more (meth)acryloyl groups, and also relates to an active energy ray-curable water-based paint containing the composition and a product coated with the paint.

[0015] [Beneficial Effects of the Invention]

[0016] The active energy ray-curable water-based resin composition of the present invention can be used for active energy ray-curable water-based coatings, which can form cured coating films with excellent adhesion, warm water resistance, and chemical resistance, and can be used to coat various products. Therefore, the active energy ray-curable water-based resin composition of the present invention can be preferably used for coating products, such as the main bodies of household appliances (such as refrigerators, televisions, air conditioners, etc.), the housings of information terminals (such as mobile phones, smartphones, personal computers, etc.), containers for automotive interior cosmetics, and packaging materials with high design characteristics. [Specific implementation method]

[0017] The active energy ray-curable aqueous resin composition of the present invention contains a reaction product (X) of an acrylic polymer (A) having a hydroxyl group and a urethane (meth)acrylate (B) having an isocyanate group, and an aqueous medium. The urethane (meth)acrylate (B) has a carboxyl group and two or more (meth)acryloyl groups.

[0018] First, the acrylic polymer (A) is described. The acrylic polymer (A) is prepared by copolymerizing an acrylic monomer (a1) having a hydroxyl group and an unsaturated monomer (a2) other than the acrylic monomer (a1).

[0019] Acrylic acid monomer (a1) is a compound having a hydroxyl group and a (meth) acryloyl group. Examples of acrylic acid monomer (a1) include: 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, N-(2-hydroxyethyl) (meth) acrylamide, glycerol mono(meth) acrylate, polyethylene glycol mono(meth) acrylate, polypropylene glycol mono(meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-(meth)acryloyloxyethyl phthalate-2-hydroxyethyl, lactone-modified (meth) acrylate having a hydroxyl group at the end, and the like. These acrylic acid monomers (a1) can be used alone or in combination of two or more.

[0020] Examples of the unsaturated monomer (a2) include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (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, cetyl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, cyclohexyl (meth)acrylate, 4-ethylhexyl (meth)acrylate, -tert-Butylcyclohexyl acrylate, isobornyl (meth)acrylate, dicyclopentyl (meth)acrylate, benzyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, ethoxypolyethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, (meth)acrylic acid, (meth)acrylamide, N,N-dimethyl(meth)acrylamide, (meth)acrylonitrile, 3-(meth)acryloylpropyltrimethoxysilane, N,N-dimethylaminoethyl (meth)acrylate, glycidyl (meth)acrylate, aromatic vinyl monomers (such as styrene, α-methylstyrene, p-methylstyrene, p-methoxystyrene), etc. These unsaturated monomers (a2) can be used alone or in combination of two or more.

[0021] From the viewpoint of the reaction point with the urethane acrylate, the amount of the used acrylic monomer (al) in the monomer component used as the raw material of the acrylic polymer (A) is preferably 5 to 70% by mass, and more preferably 10 to 50% by mass. The amount of the used unsaturated monomer (a2) is the remaining amount obtained by subtracting the ratio of the used acrylic monomer (al) from the total amount of 100% by mass of the monomer component used as the raw material of the acrylic polymer (A).

[0022] The method for producing the acrylic polymer (A) is, for example, a method of copolymerizing the acrylic monomer (al) and the unsaturated monomer (a2) using a polymerization initiator in an organic solvent. The used organic solvent is preferably an alcohol compound, a ketone compound, an ester compound, an ether compound, an amide compound, a sulfoxide compound, or a hydrocarbon compound. Examples thereof include methanol, ethanol, propanol, n-butanol, isobutanol, t-butanol, 3-methoxybutanol, acetone, methyl ethyl ketone, methyl isopropyl ketone, cyclohexanone, ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, diisopropyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol dimethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran, dioxane, toluene, xylene, and the like. Among them, from the viewpoint of improving the storage stability of the obtained active energy ray-curable water-based resin composition, a dialkylene glycol dialkyl ether such as ethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, or the like is more preferable.

[0023] Examples of polymerization initiators include organic peroxides: ketone peroxide compounds such as cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, etc.; peroxyketal compounds such as 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, 4,4-bis(tert-butylperoxy)butyl valerate, 2,2-bis(4,4-di-tert-butylperoxycyclohexyl)propane, 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, 2,2-bis(4,4-dicumylperoxycyclohexyl)propane, etc.; hydroperoxides such as cumene hydroperoxide, 2,5-dimethyl peroxide, such as decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, and the like; peroxycarbonate compounds such as bis(tert-butylcyclohexyl) peroxycarbonate, and the like; and peroxyester compounds such as tert-butyl peroxy-2-ethylhexanoate, tert-butyl perbenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, and the like; and azo compounds such as 2,2′-azobisisobutyronitrile and 1,1′-azobis(cyclohexane-1-carbonitrile).

[0024] In addition, when preparing the acrylic polymer (A), a chain transfer agent such as lauryl mercaptan, 2-mercaptoethanol, thioglycerol, ethyl mercaptoacetic acid, octyl mercaptoacetic acid, etc. can be used if necessary.

[0025] The hydroxyl value of the acrylic polymer (A) is preferably from 20 to 300 mgKOH / g, and more preferably from 40 to 200 mgKOH / g, in view of improvement in water dispersibility and water resistance of the coating film.

[0026] The weight average molecular weight (Mw) of the acrylic polymer (A) is preferably in the range of 2,000 to 50,000, more preferably in the range of 3,000 to 30,000, and still more preferably in the range of 3,000 to 20,000, in view of improving the dispersibility in water and improving the storage stability of the resulting active energy ray-curable aqueous resin composition. The weight average molecular weight (Mw) is a value in terms of polystyrene measured based on gel permeation chromatography (hereinafter abbreviated as "GPC").

[0027] The urethane (meth)acrylate (B) having an isocyanate group has an isocyanate group, a carboxyl group, and two or more (meth)acryloyl groups.

[0028] Urethane (meth)acrylate (B) can be produced, for example, by a urethane reaction of polyisocyanate (b1), polyol (b2) having a carboxyl group, and polyfunctional acrylate (b3) having a hydroxyl group, which are used as essential raw materials.

[0029] Examples of the polyisocyanate (b1) include aromatic diisocyanate compounds such as tolylene diisocyanate, diphenylmethane diisocyanate, m-xylene diisocyanate, m-phenylenebis(dimethylmethane) diisocyanate, etc.; aliphatic or alicyclic diisocyanate compounds such as hexamethylene diisocyanate, lysine diisocyanate, 1,3-bis(isocyanatemethyl)cyclohexane, 2-methyl-1,3-diisocyanatecyclohexane, 2-methyl-1,5-diisocyanatecyclohexane, 4,4′-dicyclohexylmethane diisocyanate, isophorone diisocyanate, etc., etc. Among them, aliphatic or alicyclic diisocyanate compounds are preferred due to excellent yellowing resistance.

[0030] Other available examples of the polyisocyanate (b1) include: a prepolymer having an isocyanate group prepared by an addition reaction of the above-mentioned diisocyanate compound with a polyol; a compound having an isocyanurate ring prepared by cyclotrimerization of the above-mentioned diisocyanate compound; a polyisocyanate compound having a urea bond or a biuret bond prepared by the reaction of the above-mentioned diisocyanate compound with water; a homopolymer of an acrylic monomer having an isocyanate group, such as 2-isocyanatoethyl (meth)acrylate, 3-isopropenyl-α,α-dimethylbenzyl isocyanate, (meth)acryloyl isocyanate, etc.; a copolymer having an isocyanate group prepared by copolymerizing an acrylic monomer having an isocyanate group with another acrylic monomer, a vinyl ester compound, a vinyl ether compound, an aromatic vinyl monomer, a fluoroolefin, etc.; and the like.

[0031] The polyisocyanate (b1) can be used alone or in combination of two or more.

[0032] Examples of polyols (b2) having a carboxyl group include 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, and 2,2-dimethylolvaleric acid. Among these, 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid are preferred from the perspective of reaction with isocyanates. In addition, polyester polyols having a carboxyl group, prepared by reacting a diol having a carboxyl group with various polycarboxylic acids, can be used.

[0033] The polyol (b2) having a carboxyl group may be used alone or in combination of two or more.

[0034] Examples of the polyfunctional (meth)acrylate (b3) having a hydroxyl group include trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, isocyanuric acid EO-modified diacrylate, etc. Pentaerythritol tri(meth)acrylate is preferred from the viewpoint of simultaneously satisfying both warm water resistance and water dispersibility of the coating film.

[0035] The polyfunctional (meth)acrylate (b3) having a hydroxyl group may be used alone or in combination of two or more.

[0036] If necessary, polyols having no carboxyl group and monofunctional (meth)acrylates can also be used as raw materials for the urethane (meth)acrylate (B).

[0037] Examples of the method for reacting the polyisocyanate (b1), the polyol (b2) having a carboxyl group, and the polyfunctional acrylate (b3) having a hydroxyl group include: a method of reacting the polyisocyanate (b1), the polyol (b2) having a carboxyl group, and the polyfunctional acrylate (b3) having a hydroxyl group at the same time; a method of reacting the polyisocyanate (b1) with the polyol (b2) having a carboxyl group and then reacting it with the polyfunctional acrylate (b3) having a hydroxyl group; a method of reacting the polyisocyanate (b1) with the polyfunctional acrylate (b3) having a hydroxyl group and then reacting it with the polyol (b2) having a carboxyl group, and the like.

[0038] In the present invention, the urethanization reaction can be carried out without a catalyst, but in order to promote the reaction, it can be carried out in the presence of a urethanization catalyst. Examples of urethanization catalysts include: amine compounds such as pyridine, pyrrole, triethylamine, diethylamine, dibutylamine, etc.; phosphine compounds such as triphenylphosphine, triethylphosphine, etc.; organotin compounds such as dibutyltin dilaurate, octyltin trilaurate, octyltin diacetate, dibutyltin diacetate, tin octoate, etc.; organometallic compounds such as zinc octoate, etc.; and the like.

[0039] The isocyanate group content of the urethane (meth)acrylate (B) is preferably 1% by mass to 5% by mass from the viewpoint of the warm water resistance of the resulting coating film.

[0040] The weight average molecular weight of the urethane (meth)acrylate (B) is preferably 1,000 to 10,000.

[0041] The reaction product (X) can be prepared by reacting an acrylic polymer (A) having a hydroxyl group with a urethane of a urethane (meth)acrylate (B) having an isocyanate group.

[0042] In view of the improvement of dispersibility in water and the improvement of storage stability of the resulting active energy ray-curable aqueous resin composition, the mass ratio (A / B) of the acrylic polymer (A) to the urethane (meth)acrylate (B) is preferably in the range of 0.25 to 4.0, and more preferably in the range of 0.5 to 3.0.

[0043] In view of the improvement of dispersibility in water and storage stability of the resulting active energy ray-curable aqueous resin composition, the molar ratio (A / B) of the hydroxyl group possessed by the acrylic polymer (A) to the isocyanate group possessed by the urethane (meth)acrylate is preferably in the range of 0.8 to 1.2, and more preferably in the range of 0.9 to 1.1.

[0044] In view of more improvement in water dispersibility, the acid value of the reaction product (X) is preferably 10 to 60 mgKO H / g.

[0045] The reaction product (X) is a reaction product of the acrylic polymer (A) and the urethane (meth)acrylate (B), but in view of more improvement in adhesion, preferably, the reaction product (X) is a reaction product containing polycarbonate diol (P) as an essential raw material.

[0046] Polycarbonate diols (P) are obtained, for example, by reacting diols with carbonates or phosgene.

[0047] Examples of the diol include 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-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 2,4-pentanediol, 2-methyl-1,3-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,5-hexanediol, and 2-ethyl-1,3-hexanediol. 1,4-butanediol or 1,5-pentanediol is preferred in view of greater improvement in adhesion.

[0048] In view of greater improvement in water dispersibility, the number average molecular weight of the polycarbonate diol (P) is preferably 500 to 3,000, and more preferably 500 to 2,000.

[0049] In view of greater improvement in adhesion, the amount of the polycarbonate diol (P) used in the reaction product (X) is preferably 5% by mass to 20% by mass, and more preferably 5% by mass to 10% by mass.

[0050] Examples of the reaction method of the acrylic polymer (A), the urethane (meth)acrylate (B) and the polycarbonate diol (P) include: a method of reacting the acrylic polymer (A), the urethane (meth)acrylate (B) and the polycarbonate diol (P) at the same time; a method of reacting the polyisocyanate (b1) with the polycarbonate diol (P) and then reacting with the polyol (b2) having a carboxyl group and the multifunctional acrylate (b3) having a hydroxyl group; a method of reacting the polyisocyanate (b1) with the multifunctional acrylate (b3) having a hydroxyl group and the polycarbonate diol (P) and then reacting with the polyol (b2) having a carboxyl group; and the like.

[0051] The active energy ray-curable aqueous resin composition of the present invention contains a reaction product (X) prepared by reacting an acrylic polymer (A) with a urethane (meth)acrylate (B), but in view of greater improvement in chemical resistance, the composition preferably contains a polyfunctional (meth)acrylate (C) in addition to the reaction product (X). Examples of the polyfunctional (meth)acrylate (C) include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate (1,3-butanediol di(meth)acrylate), and 1,3-butanediol di(meth)acrylate. di(meth)acrylate), 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate, bisphenol A di(meth)acrylate, bisphenol A EO-modified di(meth)acrylate, isocyanuric acid EO-modified diacrylate, isocyanuric acid EO-modified triacrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane EO-modified tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, bis(trimethylolpropane) tetraacrylate, dipentaerythritol hexa(meth)acrylate, and the like. From the viewpoint of water dispersibility of the resin and warm water resistance of the coating film, trimethylolpropane EO-modified tri(meth)acrylate is preferred.

[0052] The multifunctional (meth)acrylate (C) can be used alone or in combination of two or more.

[0053] Examples of the aqueous medium (Y) include water, a hydrophilic organic solvent, and a mixture thereof. The hydrophilic organic solvent is preferably a water-miscible organic solvent which is miscible with water without being separated from water, and is particularly preferably an organic solvent having a water solubility (g of the organic solvent dissolved in 100 g of water) of 3 g or more at 25°C. Examples of the water-miscible organic solvent include: alcohol solvents such as methanol, ethanol, propanol, butanol, 3-methoxybutanol, 3-methyl-3-methoxybutanol, and the like; ketone solvents such as acetone, methyl ether ketone, and the like; 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, dipropylene glycol dimethyl ether, and the like; and the like. These water-miscible organic solvents can be used alone or in combination of two or more.

[0054] The active energy ray-curable water-based resin composition of the present application contains the reaction product (X) and the aqueous medium (Y), and the reaction product (X) is preferably dissolved or dispersed in the aqueous medium (Y), and more preferably is a dispersion.

[0055] The method for dissolving or dispersing the reaction product (X) in the aqueous medium (Y) is preferably a method of neutralizing the acid group possessed by the reaction product (X) with a basic compound, and then mixing with the aqueous medium (Y).

[0056] Examples of the basic compound include: organic amines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, butylamine, dibutylamine, tributylamine, monoalkanolamines (such as N,N-dimethylethanolamine, 2-aminoethanol, and the like), diethanolamine, diisopropanolamine, dibutanolamine, and the like; inorganic basic compounds such as ammonia, sodium hydroxide, potassium hydroxide, and the like; quaternary ammonium hydroxides such as tetramethylammonium hydroxide, tetra-n-butylammonium hydroxide, trimethylbenzylammonium hydroxide, and the like; and the like. Among these, organic amines and ammonia (which can be aqueous ammonia) are preferably used. These basic compounds can be used alone or in combination of two or more.

[0057] In view of improving the storage stability of the active energy ray-curable water-based resin composition, the amount of the basic compound used is preferably an amount such that the neutralization ratio of the carboxyl group in the reaction product (X) is in the range of 50% to 100%.

[0058] The active energy ray-curable water-based paint of the present application contains the active energy ray-curable water-based resin composition of the present application, and other usable compounds include additives such as antistatic agents, defoaming agents, viscosity adjusting agents, light-resistant stabilizers, weather-resistant stabilizers, heat-resistant stabilizers, ultraviolet absorbers, antioxidants, leveling agents, pigment dispersants, and the like.

[0059] In addition, the cured coating film can be formed by applying the active energy ray-curable water-based paint of the present application to a substrate, and then irradiating the paint with active energy rays. The term "active energy rays" means ultraviolet light, or ionizing radiation such as electron beams, alpha rays, beta rays, gamma rays, and the like. When the cured coating film is formed by irradiation with ultraviolet light as the active energy rays, it is preferable to improve the curability by adding a photopolymerization initiator (D) to the active energy ray-curable water-based paint of the present application. If necessary, the curability can also be improved by further adding a photosensitizer. When ionizing radiation such as electron beams, alpha rays, beta rays, gamma rays, and the like is used, the curing proceeds rapidly without using a photopolymerization initiator and a photosensitizer, and therefore the addition of the photopolymerization initiator (D) and the photosensitizer is particularly not required.

[0060] Examples of the photopolymerization initiator (D) include intramolecular cleavage type photopolymerization initiators and hydrogen abstraction type photopolymerization initiators. Examples of the intramolecular cleavage type photopolymerization initiators include: acetophenone-based compounds such as diethoxyacetophenone, 2-hydroxy-2-methyl-l-phenylpropan-l-one, benzyl dimethyl ketal, l-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-l-one, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl) ketone, l-hydroxycyclohexyl-phenyl ketone, 2-methyl-2-morpholino(4-tiomethylphenyl)propan-l-one, 2-benzyl-2-dimethylamino-l-(4-morpholinophenyl)-butanone, and the like; benzoin-based compounds such as benzoin, benzoin methyl ether, benzoin isopropyl ether, and the like; acylphosphine oxide-based compounds such as 2,4,6-trimethylbenzoin diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and the like; benzyl; methylphenylglyoxyester; and the like.

[0061] On the other hand, examples of the hydrogen abstraction type photopolymerization initiator include: benzophenone-based compounds such as benzophenone, methyl-4-phenylbenzophenone, benzoylbenzoic acid ester, 4,4'-dichlorobenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, acrylated benzophenone, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, 3,3'-dimethyl-4-methoxybenzophenone, and the like; thioxanthone-based compounds such as 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, and the like; aminobenzophenone-based compounds such as Michler ketone, 4,4'-diethylaminobenzophenone, and the like; 10-butyl-2-chloroacridone, 2-ethylanthraquinone, 9,10-phenanthrenequinone, camphorquinone; and the like. These photopolymerization initiators (D) can be used alone or in combination of two or more.

[0062] Examples of the photosensitizer include: amines such as aliphatic amines, aromatic amines, and the like; ureas such as o-tolylthiourea and the like; sulfur compounds such as sodium diethyldithiophosphate, s-benzyl isothiourea p-toluenesulfonate, and the like.

[0063] In the active energy ray-curable water-based paint of the present application, the amount of each of the photopolymerization initiator and the photosensitizer used is preferably 0.05 to 20 parts by mass, and more preferably 0.5 to 10 parts by mass, with respect to 100 parts by mass of the non-volatile component.

[0064] In addition, the active energy ray-curable water-based paint can be used as a paint for coating various products. Examples of the products that can be coated with the active energy ray-curable water-based paint of the present application include: a main body of a household electric appliance such as a refrigerator, a television, an air conditioner, and the like; a housing of an information terminal such as a mobile phone, a smart phone, a personal computer, and the like; a container for a cosmetic of an automotive interior; a packaging material having a high design property; and the like.

[0065] The coating method for the active energy ray-curable water-based paint of the present application depends on the application, and examples thereof include the methods of a gravure coater, a roll coater, a comma coater, a knife coater, an air knife coater, a curtain coater, a kiss coater, a shower coater, a wheel coater, a spin coater, dip coating, screen printing, spraying, an applicator, a bar coater, and the like.

[0066] Examples of active energy rays used for curing the active energy ray-curable water-based paint of the present application include, as described above, ultraviolet light, and ionizing radiation such as electron beams, alpha rays, beta rays, gamma rays, and the like. Specific examples of energy sources or curing devices include germicidal lamps, fluorescent lamps for ultraviolet light, carbon arcs, xenon lamps, high-pressure mercury lamps for copying, medium- or high-pressure mercury lamps, ultrahigh-pressure mercury lamps, electrodeless lamps, metal halide lamps, ultraviolet light from light sources such as natural light and the like, electron beams from scanning or curtain-type electron beam accelerators, and the like.

[0067] [Examples]

[0068] The present application is described in more detail below by giving examples. In addition, the weight average molecular weight (Mw) of the polymer is measured under the following GPC measurement conditions.

[0069] [GPC Measurement Conditions]

[0070] Measurement device: High-speed GPC device

[0071] ("HLC-8220 GPC", manufactured by Tosoh Corporation)

[0072] Columns: The following columns manufactured by Tosoh Corporation were connected in series and used.

[0073] "TSKgel G5000" (7.8 mm I.D. x 30 cm) x 1

[0074] "TSKgel G4000" (7.8 mm I.D. x 30 cm) x 1

[0075] "TSKgel G3000" (7.8 mm I.D. x 30 cm) x 1

[0076] "TSKgel G2000" (7.8 mm I.D. x 30 cm) x 1

[0077] Detector: RI (differential refractometer)

[0078] Column temperature: 40°C

[0079] Eluent: Tetrahydrofuran (THF)

[0080] Flow rate: 1.0 mL / min

[0081] Injection volume: 100 μL (tetrahydrofuran solution of 4 mg / mL of sample concentration)

[0082] Standard sample: A calibration curve was formed by using the following monodisperse polystyrene.

[0083] [Monodisperse polystyrene]

[0084] "TSKgel Standard Polystyrene A-500" manufactured by Tosoh Corporation

[0085] "TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Corporation

[0086] "TSKgel Standard Polystyrene A-2500" manufactured by Tosoh Corporation

[0087] "TSKgel Standard Polystyrene A-5000" manufactured by Tosoh Corporation

[0088] "TSKgel Standard Polystyrene F-1" manufactured by Tosoh Corporation

[0089] "TSKgel Standard Polystyrene F-2" manufactured by Tosoh Corporation

[0090] "TSKgel Standard Polystyrene F-4" manufactured by Tosoh Corporation

[0091] "TSKgel Standard Polystyrene F-10" manufactured by Tosoh Corporation

[0092] "TSKgel Standard Polystyrene F-20" manufactured by Tosoh Corporation

[0093] "TSKgel Standard Polystyrene F-40" manufactured by Tosoh Corporation

[0094] "TSKgel Standard Polystyrene F-80" manufactured by Tosoh Corporation

[0095] "TSKgel Standard Polystyrene F-128" manufactured by Tosoh Corporation

[0096] "TSKgel Standard Polystyrene F-288" manufactured by Tosoh Corporation

[0097] "TSKgel Standard Polystyrene F-550" manufactured by Tosoh Corporation

[0098] (Synthesis Example 1: Synthesis of Acrylic Polymer (A-1))

[0099] In a reactor equipped with a stirrer, a thermometer, an inert gas inlet tube, a dropping funnel, and a reflux tube, 291 parts by mass of diglyme was charged as an initial solvent and heated to 130° C. Then, a monomer mixture consisting of 355.2 parts by mass of methyl methacrylate, 231.6 parts by mass of n-butyl methacrylate, 42.2 parts by mass of styrene, 90.0 parts by mass of 2-hydroxyethyl methacrylate, and 8.4 parts by mass of methoxypolyethylene glycol acrylate (“AM-130G”, manufactured by Shin-Nakamura Chemical Co., Ltd.), and an initiator solution consisting of 33.7 parts by mass of tert-butylperhydroxy 2-ethyl hexanoate and 33.7 parts by mass of diglyme were added dropwise thereto over 3 hours. The resulting mixture was maintained for 3 hours, and then the temperature was lowered to produce a solution of the acrylic polymer (A-1) having a non-volatile content of 70.1% by mass.

[0100] (Synthesis Examples 2 and 3: Synthesis of Acrylic Polymers (A-2) and (A-3))

[0101] Acrylic polymers (A-2) and (A-3) were prepared by the same method as in Synthesis Example 1, except that 2-hydroxyethyl methacrylate used in Synthesis Example 1 was replaced as shown in Table 1.

[0102] Table 1 shows the compositions of the acrylic polymers prepared in Synthesis Examples 1 to 3.

[0103] [Table 1]

[0104]

[0105] The abbreviations in Table 1 are as follows.

[0106] HEMA: Hydroxyethyl Methacrylate

[0107] FM3: 3-mol caprolactone adduct of hydroxyethyl methacrylate (manufactured by Daicel Corporation)

[0108] MMA: Methyl Methacrylate

[0109] BMA: Butyl Methacrylate

[0110] ST: Styrene

[0111] AM-130G: Methoxy polyethylene glycol acrylate (produced by Shin-Nakamura Chemical Co., Ltd.)

[0112] (Synthesis Example 4: Synthesis of Urethane (Meth)acrylate (B-1))

[0113] A reactor equipped with a stirrer, a thermometer, an inert gas inlet tube, and a reflux tube was charged with 416.7 parts by mass of isophorone diisocyanate, 485.5 parts by mass of pentaerythritol triacrylate, 3.1 parts by mass of dibutylhydroxytoluene, and 0.3 parts by mass of hydroquinone monomethyl ether (methoquinone), heated to 80°C, and reacted for 2 hours. Subsequently, 125.7 parts by mass of dimethylolpropionic acid was added, and the reaction was continued for an additional 2 hours to produce a urethane (meth)acrylate (B-1) having a carboxyl group and two or more (meth)acryloyl groups.

[0114] (Synthesis Example 5: Synthesis of Urethane (Meth)acrylate (B-2))

[0115] In a reactor equipped with a stirrer, a thermometer, an inert gas inlet tube, and a reflux tube, 416.7 parts by mass of isophorone diisocyanate, 410.5 parts by mass of pentaerythritol triacrylate, 150 parts by mass of polycarbonate diol ("DURANOL T5651", manufactured by Asahi Kasei Chemicals Corporation; hereinafter abbreviated as "polycarbonate diol (P-1)"), 3.1 parts by mass of dibutylhydroxytoluene, and 0.3 parts by mass of hydroquinone monomethyl ether were charged, heated to 80°C, and reacted for 2 hours. Then, 125.7 parts by mass of dimethylolpropionic acid was added, and the mixture was reacted for a further 2 hours to produce urethane (meth)acrylate (B-2) having a carboxyl group and two or more (meth)acryloyl groups.

[0116] (Synthesis Example 6: Synthesis of Urethane (Meth)acrylate (B-3))

[0117] A reactor equipped with a stirrer, a thermometer, an inert gas inlet, and a reflux line was charged with 416.7 parts by mass of isophorone diisocyanate, 485.5 parts by mass of EO-modified isocyanurate diacrylate, 3.1 parts by mass of dibutylhydroxytoluene, and 0.3 parts by mass of hydroquinone monomethyl ether, heated to 80°C, and reacted for 2 hours. Subsequently, 125.7 parts by mass of dimethylolpropionic acid was added, and the mixture was reacted for an additional 2 hours to produce a urethane (meth)acrylate (B-3) having a carboxyl group and two or more (meth)acryloyl groups.

[0118] (Synthesis Example 7: Synthesis of Urethane (Meth)acrylate (RB-1))

[0119] Urethane (meth)acrylate (RB-1) was prepared by the same method as in Synthesis Example 4, except that 485.5 parts by mass of pentaerythritol triacrylate used in Synthesis Example 4 was replaced with 119.1 parts by mass of 2-hydroxyethyl acrylate.

[0120] (Example 1: Synthesis of active energy ray-curable aqueous resin composition (1))

[0121] In a reactor equipped with a stirrer, a thermometer, an inert gas inlet pipe, and a reflux pipe, 1085.8 parts by mass of the acrylic polymer (A-1) prepared in Synthesis Example 1, 1031.3 parts by mass of urethane (meth)acrylate (B-1), and 228.0 parts by mass of an ethylene oxide adduct of trimethylolpropane triacrylate were charged, heated to 80° C., and reacted for 2 hours to produce a reaction product (X-1) having a carboxyl group and two or more (meth)acryloyl groups.

[0122] Next, 75.7 parts by mass of triethylamine was added, and further 2219.1 parts by mass of water was added to produce an active energy ray-curable aqueous resin composition (1).

[0123] (Examples 2 and 3: Synthesis of active energy ray-curable aqueous resin compositions (2) and (3))

[0124] Active energy ray-curable aqueous resin compositions (2) and (3) were prepared by the same method as in Example 1 except that the acrylic polymer (A-1) used in Example 1 was replaced with the acrylic polymer (A-2) or (A-3).

[0125] (Example 4: Synthesis of active energy ray-curable aqueous resin composition (4))

[0126] In a reactor equipped with a stirrer, a thermometer, an inert gas inlet pipe, and a reflux pipe, 1085.8 parts by mass of the acrylic polymer (A-1) prepared in Synthesis Example 1, 1031.3 parts by mass of urethane (meth)acrylate (B-1), 150 parts by mass of polycarbonate diol (P-1), and 228.0 parts by mass of an ethylene oxide adduct of trimethylolpropane triacrylate were charged, heated to 80° C., and reacted for 2 hours to produce a reaction product (X-1) having a carboxyl group and two or more (meth)acryloyl groups.

[0127] Next, 75.7 parts by mass of triethylamine was added, and further 2219.1 parts by mass of water was added to produce an active energy ray-curable aqueous resin composition (4).

[0128] (Examples 5 and 6: Synthesis of active energy ray-curable aqueous resin compositions (5) and (6))

[0129] Active energy ray-curable aqueous resin compositions (5) and (6) were prepared by the same method as in Example 2, except that the urethane (meth)acrylate (B-1) used in Example 2 was replaced by the urethane (meth)acrylate (B-2) or (B-3).

[0130] (Example 7: Synthesis of active energy ray-curable aqueous resin composition (7))

[0131] In a reactor equipped with a stirrer, a thermometer, an inert gas inlet pipe, and a reflux pipe, 1093.8 parts by mass of an acrylic polymer (A-2) and 1031.3 parts by mass of a urethane (meth)acrylate (B-1) were charged, heated to 80°C, and reacted for 2 hours to produce a reaction product (X-7) having a carboxyl group and two or more (meth)acryloyl groups. Subsequently, 75.7 parts by mass of triethylamine and 2219.1 parts by mass of water were added to produce an active energy ray-curable aqueous resin composition (7).

[0132] (Comparative Example 1: Synthesis of Active Energy Ray-Curable Aqueous Resin Composition (R1))

[0133] An active energy ray-curable aqueous resin composition (R1) was prepared by the same method as in Example 1 except that the urethane (meth)acrylate (B-1) used in Example 1 was replaced with the urethane (meth)acrylate (RB-1).

[0134] (Comparative Example 2: Synthesis of Active Energy Ray-Curable Aqueous Resin Composition (R2))

[0135] An active energy ray-curable aqueous resin composition (R2) was prepared by the same method as in Example 1, except that the urethane (meth)acrylate (B-1) used in Example 1 was replaced with the urethane (meth)acrylate (RB-1) and the ethylene oxide adduct of trimethylolpropane triacrylate was not used.

[0136] [Preparation of active energy ray-curable water-based coating]

[0137] The active energy ray-curable aqueous resin composition prepared as described above was mixed with a photopolymerization initiator ("Irg acure 500", manufactured by BASF Japan Ltd., a eutectic mixture of 1-hydroxycyclohexyl phenyl ketone and benzophenone at a molar ratio of 1:1) at a concentration of 5% by mass relative to the solid content of the active energy ray-curable aqueous resin composition, thereby preparing the target active energy ray-curable aqueous coating material.

[0138] [Formation of Cured Coating Film for Evaluation] ABS (acrylonitrile-butadiene-styrene copolymer) plates and PC (polycarbonate) plates were coated by spraying an active energy ray-curable water-based paint so that the film thickness after drying was 10 μm, pre-dried in a dryer at a temperature of 60° C. for 10 minutes, and then irradiated with ultraviolet light at 0.8 J / cm by using a high-pressure mercury lamp with an output of 80 W / cm 2 The coating was irradiated with an amount of radiation of 100 to form a cured coating film for evaluation.

[0139] [Evaluation of Adhesion of Coating Film]

[0140] The coating film on the ABS plate or PC plate was cut with a cutter to prepare 10×10 1-mm square cut pieces, and subjected to a peel test using a cellophane tape, and the coating film adhesion was evaluated based on the number of remaining squares according to the following criteria.

[0141] A: 95 to 100

[0142] B: 60 to 94

[0143] C: 59 or below

[0144] [Evaluation of hot water resistance]

[0145] The cured coating film on the ABS plate was immersed in warm water at 80°C for 2 hours together with the ABS plate as a substrate, then taken out and dried at 25°C for 2 hours. Then, the same peeling test using a cellophane tape as described above was performed, and the adhesion of the coating film after immersion in warm water was evaluated based on the number of remaining squares according to the following criteria.

[0146] A: 95 to 100

[0147] B: 60 to 94

[0148] C: 59 or below

[0149] [Evaluation of chemical resistance]

[0150] The cured coating film on the ABS plate was immersed in a pH 9 NaOH aqueous solution at 60°C for 1 hour together with the ABS plate as a substrate, then removed and dried at 25°C for 1 hour. The same peel test using a cellophane tape as described above was then performed, and chemical resistance was evaluated based on the number of remaining squares according to the following criteria.

[0151] A: 95 to 100

[0152] B: 60 to 94

[0153] C: 59 or below

[0154] Table 2 shows the evaluation results of Examples 1 to 4.

[0155] [Table 2]

[0156]

[0157]

[0158] Table 3 shows the evaluation results of Examples 5 to 7 and Comparative Examples 1 and 2.

[0159]

[0160] The abbreviations in Table 2 are as follows.

[0161] EOTEMPA: ethylene oxide adduct of trimethylolpropane triacrylate (about 1 mole of ethylene oxide adduct / acrylate)

[0162] It was demonstrated that the coating film formed from the active energy ray-curable water-based resin composition of the present application has excellent coating film adhesion, warm water resistance, and chemical resistance.

[0163] On the other hand, it was demonstrated that in Comparative Examples 1 and 2, which did not use the urethane (meth)acrylate (B) having a carboxyl group and two or more (meth)acryloyl groups, which is an essential component of the present application, the resulting coating film had unsatisfactory coating film adhesion, warm water resistance, and chemical resistance.

Claims

1. An active energy ray-curable water-based resin composition, comprising: a reaction product (X) of an acrylic polymer (A) having a hydroxyl group and a urethane (meth)acrylate (B) having an isocyanate group; and Aqueous medium (Y), wherein the urethane (meth)acrylate (B) has a carboxyl group and two or more (meth)acryloyl groups, and wherein the isocyanate group content in the urethane (meth)acrylate (B) is 1% by mass to 5% by mass, and wherein the active energy ray-curable aqueous resin composition further comprises a multifunctional (meth)acrylate (C), and the multifunctional (meth)acrylate (C) is selected from the group consisting of ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate, bisphenol A di(meth)acrylate, bisphenol A-EO-modified di(meth)acrylate, isocyanuric acid EO-modified diacrylate, isocyanuric acid EO-modified triacrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane EO-modified tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, bis(trimethylolpropane) tetraacrylate, and dipentaerythritol hexa(meth)acrylate. 2 . The active energy ray-curable aqueous resin composition according to claim 1 , wherein the urethane (meth)acrylate (B) is a reaction product of a polyisocyanate (b1), a polyol (b2) having a carboxyl group, and a polyfunctional (meth)acrylate (b3) having a hydroxyl group. 3 . The active energy ray-curable aqueous resin composition according to claim 1 , wherein the polyfunctional (meth)acrylate (C) is trimethylolpropane EO-modified tri(meth)acrylate. 4 . The active energy ray-curable aqueous resin composition according to claim 1 , wherein the reaction product (X) is a reaction product containing polycarbonate diol (P) as an essential raw material. 5 . An active energy ray-curable water-based paint comprising the active energy ray-curable water-based resin composition according to claim 1 . 6 . An article comprising the active energy ray-curable water-based coating material according to claim 5 coated thereon.

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