Colorant-containing core-shell particles

Abstract

To provide a coloring agent-containing core-shell particle that has excellent stability of dispersion into aqueous medium and can be used in a paint having weather resistance during formation of coating film.SOLUTION: Provided is a core-shell particle that has a core containing a coloring agent and polymer A, and a shell containing a visible light absorbing material and polymer B.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to colorant-containing core-shell particles. More specifically, the present invention relates to an aqueous dispersion containing colorant-containing core-shell particles that is useful for applications such as paints and coating agents, and a method for producing the same. [Background technology]

[0002] In recent years, from the viewpoints of environmental protection and occupational safety and health, there has been a demand for non-polluting paints and coating agents, and solvent-based paints are being replaced with water-based paints. However, many of the colorants used in paints, especially those used outdoors, are poorly soluble in water, making their preparation difficult.

[0003] For example, Patent Document 1 describes a resin dispersion comprising at least one type of resin particles selected from the group consisting of resins characterized by having a glass transition temperature of 100°C or higher, a cationic group-containing organic polymer compound, a base, and an aqueous medium, wherein the resin particles are coated with the cationic group-containing organic polymer compound.

[0004] Patent Document 2 describes an aqueous dispersion of colored particles containing a colorant and a resin, in which the difference in solubility parameter (SP value) between the colorant and the resin is 4.0 (J / cm 3 ) 1 / 2 The present invention describes an aqueous dispersion of colored fine particles characterized in that the color is within the range of 1:100 to 1:100. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2016 / 185857 [Patent Document 2] Patent Publication No. 2003-221533 Summary of the Invention [Problem to be solved by the invention]

[0006] Paints and coating agents using aqueous media are required to have dispersion stability, and when used outdoors, there is a demand for paints that are weather resistant, particularly those that reduce color deterioration of the paint film and can maintain the beauty of the paint film for a long period of time.

[0007] An object of the present invention is to provide colorant-containing core-shell particles that have excellent dispersion stability in aqueous media and can be used in paints that have weather resistance when forming a coating film. [Means for solving the problem]

[0008] The inventors have conducted studies in consideration of the above-mentioned problems and have found that core-shell particles having a core containing a colorant and polymer A and a shell containing a visible light-absorbing material and polymer B are effective in achieving excellent dispersion stability and weather resistance, thereby completing the present invention. [Effects of the Invention]

[0009] According to the present invention, the composition can be preferably used in coating materials that have excellent dispersion stability in aqueous media and weather resistance when forming a coating film. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in detail below.

[0011] In this specification, the range "X to Y" means "not less than X and not more than Y." [Core-shell particles] The core-shell particle of the present invention is characterized by having a core (hereinafter also referred to as a core layer or a core portion) containing a colorant and polymer A, and a shell (hereinafter also referred to as a shell layer or a shell portion) containing a visible light absorbing material and polymer B. The core-shell particle of the present invention may further have one or more layers other than the core layer and the shell layer.

[0012] The core of the present disclosure comprises a colorant and a polymer.

[0013] Examples of colorants of the present disclosure include oil-soluble colorants such as oil-soluble dyes, such as oil-soluble phthalocyanine-based near-infrared absorbing dyes, oil-soluble azo-based red dyes, oil-soluble chromium complex dyes, oil-soluble anthraquinone-based dyes, and oil-soluble perylene-based dyes, as well as oil-soluble ultraviolet absorbers that absorb in the visible light wavelength region, but the present invention is not limited to these examples. These colorant components may be used alone or in combination of two or more.

[0014] Polymer A of the present disclosure is a polymer having a structure derived from monomer A below. Monofunctional monomers and polyfunctional monomers can be mentioned as the monomer A. The monofunctional monomers and polyfunctional monomers may be used alone or in combination.

[0015] Examples of monofunctional monomers include ethylenically unsaturated double bond-containing monomers, but the present invention is not limited to these examples.

[0016] From the viewpoint of incorporating a colorant into the core, examples of the ethylenically unsaturated double bond-containing monomer include alkyl (meth)acrylates, acid group-containing monomers, hydroxyl group-containing (meth)acrylates, piperidyl group-containing monomers, oxo group-containing monomers, fluorine atom-containing monomers, nitrogen atom-containing monomers, epoxy group-containing monomers, alkoxyalkyl (meth)acrylates, silane group-containing monomers, carbonyl group-containing monomers, aziridinyl group-containing monomers, styrene-based monomers, and aralkyl (meth)acrylates, but the present invention is not limited to these examples. These ethylenically unsaturated double bond-containing monomers may be used alone or in combination of two or more.

[0017] As the monomer A of the present disclosure, from the viewpoints of monomer selectivity and transparency when formed into a coating film, it is preferable to use at least one monomer selected from the group consisting of alkyl (meth)acrylates having an alkyl group with 1 to 12 carbon atoms and styrene-based monomers.

[0018] Examples of alkyl (meth)acrylates having an alkyl group with 1 to 12 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, sec-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, tridecyl (meth)acrylate, cyclohexyl (meth)acrylate, n-lauryl (meth)acrylate, dodecyl (meth)acrylate, isononyl (meth)acrylate, and isobornyl (meth)acrylate, but the present invention is not limited to these examples. These monomers may be used alone or in combination of two or more. In the present invention, the alkyl (meth)acrylate is intended to encompass (meth)acrylates having an alicyclic structure.

[0019] Among the alkyl(meth)acrylates, from the viewpoint of improving the dispersion stability of the core-shell particle-containing aqueous dispersion, alkyl(meth)acrylates having 2 to 10 carbon atoms are more preferred, alkyl(meth)acrylates having 4 to 8 carbon atoms are even more preferred, and n-butyl(meth)acrylate, isobutyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, and cyclohexyl(meth)acrylate are particularly preferred. Each of these monomers may be used alone, or two or more types may be used in combination.

[0020] Examples of styrene-based monomers include alkylstyrenes having an alkyl group with 1 to 4 carbon atoms, such as styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene, tert-methylstyrene, o-tert-butylstyrene, m-tert-butylstyrene, and p-tert-butylstyrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-ethoxystyrene, m-ethoxystyrene, p-ethoxystyrene, and o-tert-butoxystyrene. Examples of suitable styrene monomers include alkoxystyrenes having an alkoxy group containing 1 to 4 carbon atoms, such as m-tert-butoxystyrene and p-tert-butoxystyrene; halogen-containing styrenes such as o-fluorostyrene, m-fluorostyrene, p-fluorostyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, o-bromostyrene, m-bromostyrene, and p-bromostyrene; acetoxystyrenes such as o-acetoxystyrene, m-acetoxystyrene, and p-acetoxystyrene; and vinyltoluene, but the present invention is not limited to these examples. These monomers may be used alone or in combination of two or more. Among styrene-based monomers, styrene and alkylstyrenes having an alkyl group containing 1 to 4 carbon atoms are preferred, with styrene being more preferred, from the viewpoint of improving the dispersion stability of the core-shell particle-containing aqueous dispersion.

[0021] The styrene-based monomer may have a substituent such as a nitro group, a nitrile group, an alkoxyl group, an acyl group, a sulfone group, a hydroxyl group, or a halogen atom present on the benzene ring.

[0022] From the viewpoint of improving the dispersion stability of the core-shell particle-containing aqueous dispersion, at least one monomer selected from the group consisting of n-butyl(meth)acrylate, isobutyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, cyclohexyl(meth)acrylate, and styrene is preferred, and from the viewpoint of obtaining an aqueous dispersion containing core-shell particles having a fine particle size, at least one monomer selected from the group consisting of n-butyl(meth)acrylate, isobutyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, and cyclohexyl(meth)acrylate is more preferred, 2-ethylhexyl(meth)acrylate and cyclohexyl(meth)acrylate are even more preferred, and cyclohexyl(meth)acrylate is particularly preferred.

[0023] As the monomer A used in the core-shell particle-containing aqueous dispersion, alkyl (meth)acrylates having an alkyl group with 1 to 12 carbon atoms and styrene-based monomers may be used alone or in combination, and it is more preferable that cyclohexyl (meth)acrylate and / or 2-ethylhexyl (meth)acrylate is used as an essential component, and at least one monomer selected from the group consisting of n-butyl (meth)acrylate and isobutyl (meth)acrylate is optionally used. From the viewpoint of improving the stability of the colorant content in the core-shell particles, it is particularly preferable that methyl (meth)acrylate is contained as part of the components of monomer A.

[0024] The monomer A preferably contains 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more, of alkyl (meth)acrylates having an alkyl group with 1 to 12 carbon atoms relative to 100% by mass of the monomer A. Furthermore, the content of alkyl (meth)acrylates having an alkyl group with 1 to 12 carbon atoms relative to 100% by mass of the monomer A is preferably 99% by mass or less, more preferably 97% by mass or less, and even more preferably 95% by mass or less. By keeping the content within the above range, the transparency of the coating film tends to be improved when used as a coating agent or the like.

[0025] The monomer A preferably contains 0% by mass or more of styrene-based monomers in total, more preferably 1% by mass or more, and even more preferably 3% by mass or more, relative to 100% by mass of the monomer A. Furthermore, the content of the styrene-based monomers in total, relative to 100% by mass of the monomer A, is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less. By keeping the content within the above range, the transparency of the coating film tends to be improved when used as a coating agent or the like. From the viewpoint of improving the stability of the colorant content, the monomer A of the present disclosure preferably contains, as a component of the monomer A, a polyfunctional (meth)acrylate having two or more radical polymerization groups in its structure.

[0026] Examples of polyfunctional (meth)acrylates include triallyl compounds having 9 to 20 carbon atoms, such as triallyl cyanurate (triallyl cyanurate), triallyl isocyanurate, triallyl phosphate, and triallylamine; ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and ethylene oxide-modified 1,6-hexanediol di(meth)acrylate. di(meth)acrylates of polyhydric alcohols having 1 to 10 carbon atoms, such as 1,9-nonanediol di(meth)acrylate, propylene oxide-modified neopentyl glycol di(meth)acrylate, and tripropylene glycol di(meth)acrylate; alkyleneoxy groups having 2 to 4 carbon atoms, such as polyethylene glycol di(meth)acrylate having 2 to 50 moles of ethylene oxide added, polypropylene glycol di(meth)acrylate having 2 to 50 moles of propylene oxide added, and tripropylene glycol di(meth)acrylate; Alkyl di(meth)acrylates having 2 to 50 moles of alkyl groups added; tri(meth)acrylates of polyhydric alcohols having 1 to 10 carbon atoms, such as ethoxylated glycerin tri(meth)acrylate, propylene oxide-modified glycerol tri(meth)acrylate, ethylene oxide-modified trimethylolpropane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol monohydroxytri(meth)acrylate, and trimethylolpropane triethoxytri(meth)acrylate; pentaerythritol tetra(meth)acrylates of polyhydric alcohols having 1 to 10 carbon atoms, such as pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and ditrimethylolpropane tetra(meth)acrylate; penta(meth)acrylates of polyhydric alcohols having 1 to 10 carbon atoms, such as pentaerythritol penta(meth)acrylate and dipentaerythritol (monohydroxy)penta(meth)acrylate; hexa(meth)acrylates of polyhydric alcohols having 1 to 10 carbon atoms, such as pentaerythritol hexa(meth)acrylate;Examples of suitable polyfunctional (meth)acrylates include bisphenol A di(meth)acrylate, but the present invention is not limited to these examples. These polyfunctional monomers may be used alone or in combination of two or more.

[0027] From the viewpoint of increasing the amount of colorant introduced, the monomer A of the present disclosure preferably contains a nitrogen atom-containing monomer as part of its components.

[0028] Examples of the nitrogen atom-containing ethylenically unsaturated monomer include acrylamide compounds such as (meth)acrylamide, N-monomethyl(meth)acrylamide, N-monoethyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, Nn-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, methylenebis(meth)acrylamide, N-methylol(meth)acrylamide, N-butoxymethyl(meth)acrylamide, dimethylaminoethyl(meth)acrylamide, N,N-dimethylaminopropylacrylamide, and diacetone acrylamide; nitrogen atom-containing (meth)acrylate compounds such as dimethylaminoethyl(meth)acrylate and diethylaminoethyl(meth)acrylate; N-vinylpyrrolidone, (meth)acrylonitrile, N-phenylmaleimide, N-benzylmaleimide, and N-cyclohexylmaleimide; however, the present invention is not limited to these examples. These nitrogen atom-containing ethylenically unsaturated monomers may be used alone or in combination of two or more kinds, but N-vinylpyrrolidone is preferred from the viewpoint of improving the dispersion stability of the core-shell particle-containing aqueous dispersion.

[0029] The content of the monomer A of the present disclosure is preferably 5% by mass or more, more preferably 7% by mass or more, even more preferably 10% by mass or more, and even more preferably 12% by mass or more, relative to 100 parts by mass of the solid content in the core-shell particle-containing aqueous dispersion, from the viewpoint of obtaining an aqueous dispersion containing core-shell particles having a fine particle size, and is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less, from the viewpoint of improving the dispersion stability of the core-shell particle-containing aqueous dispersion.

[0030] The content of the colorant component of the present disclosure cannot be determined in general because it varies depending on the type of colorant component, but from the viewpoint of fully expressing the properties of the colorant component, it is preferably 0.03 mass% or more, more preferably 0.1 mass% or more, even more preferably 0.3 mass% or more, and even more preferably 0.5 mass% or more, relative to 100 parts by mass of the core-shell particles. From the viewpoint of improving the dispersion stability of the core-shell particle-containing aqueous dispersion, it is preferably 50 mass% or less, more preferably 40 mass% or less, even more preferably 30 mass% or less, and even more preferably 25 mass% or less. Therefore, the content of the lipophilic active ingredient in the monomer component is preferably 0.03 to 50 mass%, more preferably 0.1 to 50 mass%, even more preferably 0.3 to 40 mass%, even more preferably 0.4 to 30 mass%, and even more preferably 0.4 to 25 mass%.

[0031] The content of polymer A of the present disclosure is preferably 0.03% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more, relative to 100 parts by mass of core-shell particles, from the viewpoint of dispersion stability of the colorant, and is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, and even more preferably 25% by mass or less, from the viewpoint of improving the dispersion stability of the core-shell particle-containing aqueous dispersion. Therefore, the content of the lipophilic active ingredient in the monomer component is preferably 0.03 to 50% by mass, more preferably 0.1 to 50% by mass, even more preferably 0.3 to 40% by mass, even more preferably 0.5 to 30% by mass, and even more preferably 0.5 to 25% by mass.

[0032] In addition to the colorant and polymer A, the core particle of the present disclosure may contain other compounds, such as visible light absorbing materials, ultraviolet stabilizers (excluding oil-soluble ultraviolet absorbers having absorption in the visible light wavelength region), fatty acid esters, surfactants, and the like, as well as other compounds, such as antioxidants and polymerization initiators, and is not limited to these examples.

[0033] The mass ratio of the colorant to the polymer A in the core-shell particles of the present disclosure is preferably from 1 / 99 to 30 / 70, more preferably from 2 / 98 to 25 / 75, and even more preferably from 3 / 97 to 20 / 80.

[0034] The fatty acid ester used in the core-shell particles of the present disclosure is preferably an ester of a fatty acid and a monohydric alcohol. The fatty acid residue forming the fatty acid ester may be a fatty acid having 1 to 25 carbon atoms, and the alkyl ester moiety derived from the monohydric alcohol may have 5 to 25 carbon atoms.

[0035] The fatty acid ester of the present disclosure may be a fatty acid ester having 15 or more carbon atoms, specifically, the fatty acid residue may have 15 or more carbon atoms, or the alkyl ester moiety may have 15 or more carbon atoms, and it is more preferable that the total carbon number of the compound is 15 or more. From the viewpoint of improving the dispersion stability of the core-shell particle-containing aqueous dispersion, the lower limit of the carbon number of the fatty acid ester having 15 or more carbon atoms is 15 or more, preferably 18 or more, more preferably 21 or more, and even more preferably 23 or more, and the upper limit is not particularly limited, but is preferably 60 or less, more preferably 50 or less, and even more preferably 40 or less, from the viewpoint of easy availability of raw materials.

[0036] The fatty acid ester having 15 or more carbon atoms may have a polymerizable unsaturated double bond. Although the fatty acid ester having 15 or more carbon atoms and a polymerizable unsaturated double bond has a polymerizable unsaturated double bond, it is not included in the monofunctional monomer in this specification.

[0037] Examples of fatty acid esters having 15 or more carbon atoms include fatty acid esters having an alkyl ester moiety with a polymerizable unsaturated double bond and a carbon number of 14 or more, such as tetradecyl (meth)acrylate, hexadecyl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, eicosyl (meth)acrylate, and 2-decyltetradecyl (meth)acrylate; fatty acid esters having an alkyl ester moiety with a carbon number of 14 or more, such as hexadecyl 2-ethylhexanoate, myristyl myristate, stearyl myristate, stearyl 2-ethylhexanoate, and stearyl stearate; and fatty acid esters having an alkyl group with a carbon number of 14 or more, such as ethyl myristate, isopropyl myristate, butyl myristate, ethyl palmitate, ethyl stearate, and 2-ethylhexyl stearate. However, the present invention is not limited to these examples. These fatty acid esters may be used alone or in combination of two or more. Among fatty acid esters having 15 or more carbon atoms, fatty acid esters having 14 or more carbon atoms in the alkyl ester moiety are preferred from the viewpoint of improving the dispersion stability of the core-shell particle-containing aqueous dispersion, and hexadecyl 2-ethylhexanoate, myristyl myristate, stearyl myristate, stearyl 2-ethylhexanoate, and stearyl stearate are more preferred.

[0038] The amount of fatty acid ester contained in 100 parts by mass of solids in the core-shell particle-containing aqueous dispersion of the present disclosure is preferably 1 part by mass or more, more preferably 2 parts by mass or more, even more preferably 3 parts by mass or more, particularly preferably 3.5 parts by mass or more, and is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, even more preferably 12 parts by mass or less, and particularly preferably 10 parts by mass or less.

[0039] The fatty acid ester of the present disclosure is preferably contained in the core of the core-shell particles, and the content of the fatty acid ester is preferably 3 parts by mass or more, more preferably 4 parts by mass or more, even more preferably 5 parts by mass or more, particularly preferably 6 parts by mass or more, preferably 20 parts by mass or less, more preferably 19 parts by mass or less, even more preferably 18 parts by mass or less, and particularly preferably 17 parts by mass or less, relative to 100 parts by mass of the total of the compounds forming the core, from the viewpoint of obtaining an aqueous dispersion containing core-shell particles having a fine particle diameter.

[0040] The core-shell particles of the present disclosure may be dispersed in an aqueous solvent using a surfactant, and in this case, the core-shell particles may contain a surfactant. Examples of the surfactant include anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, and polymer surfactants. These surfactants may be used alone or in combination of two or more types. However, from the viewpoint of obtaining an aqueous dispersion containing core-shell particles having a fine particle size, nonionic surfactants are preferred.

[0041] Examples of nonionic surfactants of the present disclosure include polyoxyethylene alkyl ethers, polyoxyethylene alkylaryl ethers, condensates of polyethylene glycol and polypropylene glycol, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, fatty acid monoglycerides, condensation products of ethylene oxide and aliphatic amines, allyloxymethylalkoxyethylhydroxypolyoxyethylene, polyoxyalkylene alkenyl ethers, and the like; however, the present invention is not limited to these examples.

[0042] From the viewpoint of obtaining an aqueous dispersion containing core-shell particles having a fine particle diameter, the content of the surfactant of the present disclosure is preferably 5 parts by mass or more, more preferably 6 parts by mass or more, even more preferably 7 parts by mass or more, and particularly preferably 8 parts by mass or more, relative to 100 parts by mass of the solid content in the core-shell particle-containing aqueous dispersion; from the viewpoint of obtaining an aqueous dispersion containing core-shell particles having a fine particle diameter, the content of the surfactant is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, even more preferably 40 parts by mass or less, and particularly preferably 30 parts by mass or less.

[0043] The weight-average molecular weight of polymer A of the present disclosure is preferably 50,000 or more, more preferably 100,000 or more, and even more preferably 150,000 or more, from the viewpoint of improving the dispersion stability of the core-shell particle-containing aqueous dispersion. The upper limit is not particularly limited because it is difficult to measure the weight-average molecular weight when a crosslinked structure is present, but when a crosslinked structure is not present, it is preferably 5,000,000 or less from the viewpoint of improving film-forming properties.

[0044] The glass transition temperature of the polymer A of the present disclosure is preferably −40° C. or higher, more preferably −30° C. or higher, and even more preferably −20° C. or higher, from the viewpoint of improving the stability of the colorant content; and is preferably 120° C. or lower, more preferably 110° C. or lower, and even more preferably 100° C. or lower, from the viewpoint of film-forming properties when made into a coating film.

[0045] The glass transition temperature of polymer A can be calculated using the glass transition temperatures of the homopolymers of the monomers used in the monomer components constituting the polymer A according to the formula (I): 1 / Tg=Σ(Wm / Tgm) / 100 (I) (wherein Wm represents the content (mass%) of monomer m in the monomer components constituting the polymer, and Tgm represents the glass transition temperature (absolute temperature: K) of a homopolymer of monomer m.) This refers to the temperature calculated based on the Fox equation,

[0046] For monomers with unknown glass transition temperatures, such as special monomers and polyfunctional monomers, if the total amount of monomers with unknown glass transition temperatures in the monomer composition is 10% by mass or less, the glass transition temperature can be determined using only monomers with known glass transition temperatures. If the total amount of monomers with unknown glass transition temperatures in the monomer composition exceeds 10% by mass, the glass transition temperature of the polymer can be determined by differential scanning calorimetry (DSC), differential thermal analysis (DTA), thermomechanical analysis (TMA), etc.

[0047] The glass transition temperature of the polymer can be easily adjusted by adjusting the composition of the monomer components. The composition of the monomer components used as raw materials for the polymer constituting the emulsion particles can be determined in consideration of the glass transition temperature of the polymer constituting the emulsion particles.

[0048] The glass transition temperatures of the polymers are, for example, −70°C for a homopolymer of 2-ethylhexyl acrylate, −56°C for a homopolymer of n-butyl acrylate, 20°C for a homopolymer of n-butyl methacrylate, 105°C for a homopolymer of methyl methacrylate, 83°C for a homopolymer of cyclohexyl methacrylate, 107°C for a homopolymer of tert-butyl methacrylate, 100°C for a homopolymer of styrene, 95°C for a homopolymer of acrylic acid, 130°C for a homopolymer of methacrylic acid, 55°C for a homopolymer of 2-hydroxyethyl methacrylate, 77°C for a homopolymer of diacetone acrylamide, 70°C for a homopolymer of γ-methacryloxypropyltrimethoxysilane, approximately 130°C for a homopolymer of 4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine, and 55°C for a homopolymer of glycerin monomethacrylate.

[0049] The core-shell particles of the present disclosure preferably have a core layer particle size of 10 nm or more and 150 nm or less, more preferably 15 nm or more and 100 nm or less, and even more preferably 20 nm or more and 80 nm or less. By setting the particle size within the above range, when used as a coating agent, the transparency of the coating film tends to be improved.

[0050] The shell of the present disclosure comprises a visible light absorbing material and polymer B.

[0051] The visible light absorbing material of the present disclosure is not particularly limited as long as it is a compound that has absorption in the wavelength region of the visible light region (360 to 750 nm). From the viewpoint of weather resistance when used as a coating film, the visible light absorbing material is preferably a compound that has absorption at a maximum absorption wavelength of 360 nm or more and 650 nm or less, and may also have absorption in the ultraviolet region (400 nm or less). The visible light absorbing material may be, for example, an inorganic substance such as a pigment containing a metal oxide as a main component or metal fine particles, or may be an organic substance such as a black colorant such as carbon black, an ultraviolet stabilizer that absorbs in the long wavelength region, or an ultraviolet absorber.

[0052] Examples of visible light absorbing materials include black colorants, cyan colorants, magenta colorants, and yellow colorants.

[0053] Examples of black colorants include carbon black, carbon nanotubes, graphite, copper oxide, manganese dioxide, azo pigments such as azomethine azo black, aniline black, perylene black, titanium black, cyanine black, activated carbon, ferrite, magnetite, chromium oxide, iron oxide, molybdenum disulfide, composite oxide black pigments, anthraquinone organic black dyes, and azo organic black dyes.

[0054] The visible light absorbing material may be a pigment (visible light absorbing pigment) or a dye (visible light absorbing dye), but dyes are preferred from the viewpoint of uniformity of the coating film. The visible light absorbing dye is preferably a dye that has a maximum absorbance value in the wavelength region of 350 to 700 nm. Examples of the visible light absorbing dye include anthraquinone dyes, perinone dyes, perylene dyes, quinoline dyes, quinacridone dyes, benzimidazolone dyes, azo dyes, isoindolinone dyes, isoindoline dyes, dioxazine dyes, phthalocyanine dyes, and methine dyes. The visible light absorbing dyes may be used singly or in combination of two or more.

[0055] The visible light absorbing material may be a fluorescent dye from the viewpoint of converting light of a wavelength that accelerates fading into another wavelength. The fluorescent dye may be a pigment (fluorescent pigment) or a dye (fluorescent dye), but from the viewpoint of uniformity of the coating film, a dye is preferred. The fluorescent dye is preferably a dye having a maximum absorbance value in the wavelength region of 350 to 700 nm. From the viewpoint of weather resistance, the fluorescent dye is preferably a perylene dye. The fluorescent dye may be used alone or in combination of two or more types. As the visible light absorbing material, an ultraviolet absorber having absorption in the long wavelength region can also be used.

[0056] Examples of ultraviolet absorbers having absorption in the long wavelength region include benzophenone-based compounds, salicylate-based compounds, benzoate-based compounds, benzotriazole-based compounds, and triazine-based compounds.

[0057] Examples of benzotriazole compounds include 2-(2H-benzotriazol-2-yl)-4-methyl-6-(3,4,5,6-tetrahydrophthalividylmethyl)phenol, 2-(2H-benzotriazol-2-yl)-p-cresol, 2-(2H-benzotriazol-2-yl)-4-tert-butylphenol, 2-(2H-benzotriazol-2-yl)-4,6-di-tert-butylphenol, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethyl-1-phenylethyl)phenol, and 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethyl-1-phenylethyl)phenol. 2-(2H-benzotriazol-2-yl)-4-(3-one-4-oxa-dodecyl)-6-tert-butyl-phenol, 2-{5-chloro(2H)-benzotriazol-2-yl}-4-(3-one-4-oxa-dodecyl)-6-tert-butyl-phenol, 2-{5-chloro(2H)-benzotriazol-2-yl}-4-methyl-6-tert-butyl-phenol, 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol, 2-{5-chloro(2H)-benzotriazol-2-yl}-4,6-Di-tert-butylphenol, 2-(2H-benzotriazol-2-yl)-4-tert-octylphenol, 2-(2H-benzotriazol-2-yl)-4-methyl-6-n-dodecylphenol, octyl 3-[3-tert-butyl-5-(5-chloro-2H-benzotriazol-2-yl)-4-hydroxyphenyl]propionate, 2-ethylhexyl 3-[3-tert-butyl-5-(5-chloro-2H-benzotriazol-2-yl)-4-hydroxyphenyl]propionate, methyl- Examples include a reaction product of 3-{3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl}propionate / polyethylene glycol 300, and commercially available benzotriazole-based ultraviolet absorbers such as Viosorb 583 (Kyodo Pharmaceutical Co., Ltd.), Tinuvin 326 (BASF), Tinuvin 384-2 (BASF), Tinuvin PS (BASF), Tinuvin 970 (BASF), Seesorb 706 (Shipro Chemical Co., Ltd.), and EVERSORB 109 (EVER LIGHT).

[0058] Examples of triazine compounds include 2-(4-phenoxy-2-hydroxy-phenyl)-4,6-diphenyl-1,3,5-triazine, 2-(2-hydroxy-4-oxa-hexadecyloxy)-4,6-di(2,4-dimethyl-phenyl)-1,3,5-triazine, 2-(2-hydroxy-4-oxa-heptadecyloxy)-4,6-di(2,4-dimethyl-phenyl)-1,3,5-triazine, and 2-(2-hydroxy-4-oxa-heptadecyloxy)-4,6-di(2,4-dimethyl-phenyl)-1,3,5-triazine. Examples of commercially available products include triazine-based ultraviolet absorbers under the trade names of TINUVIN 400 (manufactured by BASF), TINUVIN 405 (manufactured by BASF), TINUVIN 460 (manufactured by BASF), TINUVIN 479 (manufactured by BASF), and Adeka STAB LA-F70 (manufactured by ADEKA).

[0059] Examples of benzophenone compounds include benzophenone ultraviolet absorbers such as 2-hydroxy-4-n-methoxybenzophenone and 2-hydroxy-4-n-octoxybenzophenone, and examples of benzoate compounds include benzoate ultraviolet absorbers such as 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate, and a commercially available product thereof is SB-UVA650 (manufactured by SHUANG BANG INDUSTRIAL CORP.). Among these ultraviolet absorbers, benzotriazole and triazine ultraviolet absorbers tend to be preferred from the viewpoint of suppressing deterioration of the colorant in the core of the core-shell particles.

[0060] The polymer B of the present disclosure is a polymer having a structure derived from the following monomer B.

[0061] Monomer B of the present disclosure includes monofunctional monomers and polyfunctional monomers. The monofunctional monomers and polyfunctional monomers may be used alone or in combination.

[0062] Examples of monofunctional monomers include ethylenically unsaturated double bond-containing monomers, but the present invention is not limited to these examples.

[0063] Examples of ethylenically unsaturated double bond-containing monomers include alkyl (meth)acrylates, acid group-containing monomers, hydroxyl group-containing (meth)acrylates, piperidyl group-containing monomers, oxo group-containing monomers, fluorine atom-containing monomers, amide group-containing monomers, epoxy group-containing monomers, alkoxyalkyl (meth)acrylates, silane group-containing monomers, carbonyl group-containing monomers, aziridinyl group-containing monomers, styrene-based monomers, and aralkyl (meth)acrylates, but the present invention is not limited to these examples. These ethylenically unsaturated double bond-containing monomers may be used alone or in combination of two or more.

[0064] Examples of alkyl (meth)acrylates include alkyl (meth)acrylates having an ester moiety of 1 to 18 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, sec-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, tridecyl (meth)acrylate, cyclohexyl (meth)acrylate, n-lauryl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, and isobornyl methacrylate, but the present invention is not limited to these examples. These monomers may be used alone or in combination of two or more.

[0065] Examples of the acid group-containing monomer include, but are not limited to, carboxyl group-containing aliphatic monomers such as (meth)acrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, maleic anhydride, maleic acid monomethyl ester, maleic acid monobutyl ester, itaconic acid monomethyl ester, itaconic acid monobutyl ester, and vinylbenzoic acid.

[0066] Examples of hydroxyl group-containing (meth)acrylates include hydroxyl group-containing (meth)acrylates having an ester group containing 1 to 18 carbon atoms, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate, but are not limited to these examples. Among these, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred. These hydroxyl group-containing (meth)acrylates may be used alone or in combination of two or more.

[0067] Examples of oxo group-containing monomers include, but are not limited to, (di)ethylene glycol (methoxy) (meth)acrylates such as ethylene glycol (meth)acrylate, ethylene glycol methoxy (meth)acrylate, diethylene glycol (meth)acrylate, and diethylene glycol methoxy (meth)acrylate. These oxo group-containing monomers may be used alone or in combination of two or more.

[0068] Examples of fluorine atom-containing monomers include, but are not limited to, fluorine atom-containing alkyl (meth)acrylates having an ester group containing 2 to 6 carbon atoms, such as trifluoroethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, and octafluoropentyl (meth)acrylate. These fluorine atom-containing monomers may be used alone or in combination of two or more.

[0069] Examples of amide group monomers include, but are not limited to, acrylamide compounds such as (meth)acrylamide, N-monomethyl(meth)acrylamide, N-monoethyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, Nn-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, methylenebis(meth)acrylamide, N-methylol(meth)acrylamide, N-butoxymethyl(meth)acrylamide, dimethylaminoethyl(meth)acrylamide, N,N-dimethylaminopropylacrylamide, and diacetone acrylamide, and N-vinylpyrrolidone. Among these, (meth)acrylamide, diacetone acrylamide, and N-vinylpyrrolidone are preferred. These amide group-containing monomers may be used alone or in combination of two or more.

[0070] Examples of epoxy group-containing monomers include, but are not limited to, epoxy group-containing (meth)acrylates such as glycidyl (meth)acrylate, α-methylglycidyl (meth)acrylate, and glycidyl allyl ether. These epoxy group-containing monomers may be used alone or in combination of two or more.

[0071] Examples of alkoxyalkyl (meth)acrylates include, but are not limited to, methoxyethyl (meth)acrylate, methoxybutyl (meth)acrylate, ethoxybutyl (meth)acrylate, trimethylolpropane tripropoxy (meth)acrylate, etc. These alkoxyalkyl (meth)acrylates may be used alone or in combination of two or more.

[0072] Examples of silane group-containing monomers include, but are not limited to, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(methoxyethoxy)silane, γ-(meth)acryloyloxypropyltrimethoxysilane, 2-styrylethyltrimethoxysilane, vinyltrichlorosilane, γ-(meth)acryloyloxypropylhydroxysilane, and γ-(meth)acryloyloxypropylmethylhydroxysilane. These silane group-containing monomers may be used alone or in combination of two or more.

[0073] Examples of carbonyl group-containing monomers include, but are not limited to, acrolein, humyl styrene, vinyl ethyl ketone, (meth)acryloxyalkyl propenal, acetonyl (meth)acrylate, diacetone (meth)acrylate, 2-hydroxypropyl (meth)acrylate acetylacetate, butanediol-1,4-acrylate acetylacetate, and 2-(acetoacetoxy)ethyl (meth)acrylate. Among these, 2-(acetoacetoxy)ethyl (meth)acrylate is preferred. These carbonyl group-containing monomers may be used alone or in combination of two or more.

[0074] Examples of the aziridinyl group-containing monomer include, but are not limited to, (meth)acryloylaziridine, 2-aziridinylethyl (meth)acrylate, etc. These aziridinyl group-containing monomers may be used alone or in combination of two or more.

[0075] Examples of styrene-based monomers include, but are not limited to, styrene, α-methylstyrene, p-methylstyrene, tert-methylstyrene, chlorostyrene, and vinyltoluene. These styrene-based monomers may be used alone or in combination of two or more. The styrene-based monomer may have a functional group such as an alkyl group (e.g., methyl group, tert-butyl group), a nitro group, a nitrile group, an alkoxyl group, an acyl group, a sulfone group, a hydroxyl group, or a halogen atom on the benzene ring. Among styrene-based monomers, styrene is preferred from the viewpoint of enhancing water resistance.

[0076] Examples of aralkyl (meth)acrylates include, but are not limited to, aralkyl (meth)acrylates having an aralkyl group having 7 to 18 carbon atoms, such as benzyl (meth)acrylate, phenylethyl (meth)acrylate, methylbenzyl (meth)acrylate, and naphthylmethyl (meth)acrylate. These aralkyl (meth)acrylates may be used alone or in combination of two or more.

[0077] Furthermore, from the viewpoint of imparting UV stability or UV absorption to the core-shell particles, it is preferable that a UV-stable monomer or a UV-absorbing monomer is contained in the monomer B forming the polymer B, within the range not impairing the object of the present invention. By imparting UV absorption to the resin layer, it is possible to obtain an aqueous dispersion containing core-shell particles having excellent film-forming properties and weather resistance.

[0078] Examples of ultraviolet-stable monomers include 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4-(meth)acryloyl-1-methoxy-2,2,6,6-tetramethylpiperidine, 4-cyano-4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 1-(meth)acryloyl-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, and 4-crotonoyl Examples of the monomers include 4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloylamino-1,2,2,6,6-pentamethylpiperidine, 4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 1-(meth)acryloyl-4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, and 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, but the present invention is not limited to these examples. These monomers may be used alone or in combination of two or more. Among these ultraviolet-stable monomers, piperidyl group-containing (meth)acrylates such as 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine, and 4-cyano-4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine are preferred.

[0079] Examples of ultraviolet absorbing monomers include benzotriazole-based ultraviolet absorbing monomers and benzophenone-based ultraviolet absorbing monomers, but the present invention is not limited to these examples. These monomers may be used alone or in combination of two or more.

[0080] Examples of the benzotriazole-based ultraviolet absorbing monomer include 2-[2'-hydroxy-5'-(meth)acryloyloxymethylphenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxyethylphenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxymethylphenyl]-5-tert-butyl-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxymethylphenyl]-5-tert-butyl-2H-benzotriazole, ) acryloylaminomethyl-5'-tert-octylphenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxypropylphenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxyhexylphenyl]-2H-benzotriazole, 2-[2'-hydroxy-3'-tert-butyl-5'-(meth)acryloyloxyethylphenyl]-2H-benzotriazole , 2-[2'-hydroxy-3'-tert-butyl-5'-(meth)acryloyloxyethylphenyl]-5-chloro-2H-benzotriazole, 2-[2'-hydroxy-5'-tert-butyl-3'-(meth)acryloyloxyethylphenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxyethylphenyl]-5-chloro-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxyethylphenyl]-5-chloro-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxyethylphenyl]-5-chloro-2H-benzotriazole Examples of the monomers include 2-[2'-hydroxy-5'-(β-(meth)acryloyloxyethoxy)-3'-tert-butylphenyl]-5-cyano-2H-benzotriazole, 2-[2'-hydroxy-5'-(β-(meth)acryloyloxyethoxy)-3'-tert-butylphenyl]-4-tert-butyl-2H-benzotriazole, but the present invention is not limited to these examples. These monomers may be used alone or in combination of two or more.

[0081] Examples of benzophenone-based ultraviolet-absorbing monomers include 2-hydroxy-4-(meth)acryloyloxybenzophenone, 2-hydroxy-4-[2-hydroxy-3-(meth)acryloyloxy]propoxybenzophenone, 2-hydroxy-4-[2-(meth)acryloyloxy]ethoxybenzophenone, 2-hydroxy-4-[3-(meth)acryloyloxy-2-hydroxypropoxy]benzophenone, and 2-hydroxy-3-tert-butyl-4-[2-(meth)acryloyloxy]butoxybenzophenone, but the present invention is not limited to these examples. These monomers may be used alone or in combination of two or more.

[0082] The monomer B preferably contains 60% by mass or more of alkyl (meth)acrylate in total, relative to 100% by mass of the monomer B, more preferably 70% by mass or more, and even more preferably 80% by mass or more. Furthermore, the content of alkyl (meth)acrylate in total, relative to 100% by mass of the monomer B, is preferably 100% by mass or less, more preferably 99% by mass or less, and even more preferably 98% by mass or less. By ensuring the content is within the above range, the transparency of the coating film tends to be improved when used as a coating agent or the like.

[0083] The content of the ultraviolet-stable monomer in polymer B is preferably 1 to 5 mass % from the viewpoint of improving the ultraviolet stability and the dispersion stability of the core-shell particle-containing aqueous dispersion. The content of the ultraviolet-absorbing monomer in monomer B is preferably 1 to 5 mass % from the viewpoint of improving the ultraviolet stability and the dispersion stability of the core-shell particle-containing aqueous dispersion.

[0084] The weight-average molecular weight of polymer B of the present disclosure is preferably 100,000 or more, more preferably 150,000 or more, and even more preferably 200,000 or more, from the viewpoint of improving the dispersion stability of the core-shell particle-containing aqueous dispersion. The upper limit is not particularly limited because it is difficult to measure the weight-average molecular weight when a crosslinked structure is present, but when a crosslinked structure is not present, it is preferably 5,000,000 or less, from the viewpoint of improving film-forming properties.

[0085] The glass transition temperature of the polymer B of the present disclosure is preferably −50° C. or higher, more preferably −40° C. or higher, and even more preferably −30° C. or higher, from the viewpoint of improving the dispersion stability of the core-shell particle-containing aqueous dispersion; and is preferably 80° C. or lower, more preferably 70° C. or lower, and even more preferably 60° C. or lower, from the viewpoint of film-forming properties when used as a coating film.

[0086] The glass transition temperature of polymer B can be determined by the same method as for polymer A.

[0087] The average particle size of the core-shell particles of the present disclosure is preferably 10 nm or more, more preferably 15 nm or more, and particularly preferably 20 nm or more, and is preferably 200 nm or less, more preferably 150 nm or less, and particularly preferably 100 nm or less, from the viewpoint of contributing to the dispersion stability of the aqueous dispersion and contributing to the transparency of a coating film. The average particle size of the core-shell particles of the present disclosure is measured in accordance with JIS Z 8828, measured by a dynamic light scattering method, and is defined as the cumulant average particle size, and can be specifically measured by the method described in the Examples. [Aqueous dispersion containing core-shell particles] From the viewpoints of environmental protection and occupational safety and hygiene, the core-shell particles of the present disclosure are preferably used in an aqueous medium, ie, an aqueous dispersion.

[0088] Examples of aqueous media in the present disclosure include water and mixed solvents of water and water-soluble organic solvents. Examples of water-soluble organic solvents include lower alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, and tert-butyl alcohol; polyhydric alcohols such as ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, and diethylene glycol; and ketones such as acetone and methyl ethyl ketone, but the present invention is not limited to these examples. These aqueous media may be used alone or in combination of two or more. From the viewpoint of improving the dispersion stability of the core-shell particle-containing aqueous dispersion, the water content in the aqueous medium is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and even more preferably 80% by mass or more, with the upper limit of this content being 100% by mass. Among aqueous media, water is preferred.

[0089] The solid content (non-volatile content) of the core-shell particle-containing aqueous dispersion of the present disclosure is preferably adjusted appropriately depending on the application of the core-shell particle-containing aqueous dispersion, but from the viewpoint of improving productivity, it is preferably 20% by mass or more, more preferably 25% by mass or more, and from the viewpoint of improving handleability, it is preferably 70% by mass or less, more preferably 60% by mass or less. Therefore, the solid content of the core-shell particle-containing aqueous dispersion is preferably 20 to 70% by mass, more preferably 25 to 60% by mass.

[0090] In this specification, the solid content of the aqueous resin dispersion is determined by weighing 1 g of the aqueous resin dispersion, drying it in a hot air dryer at a temperature of 110°C for 1 hour, and taking the resulting residue as the nonvolatile content, and calculating it using the formula: [Solid content (mass%) in aqueous resin dispersion] = ([mass of residue] ÷ [1 g of aqueous resin dispersion]) × 100 This means the value calculated based on

[0091] The core-shell particle-containing aqueous dispersion of the present disclosure may contain other additives within the range that does not impair the object of the present invention.

[0092] Other additives include, for example, colorants such as pigments, leveling agents, UV absorbers, UV stabilizers, antioxidants, polymerization inhibitors, fillers, coupling agents, rust inhibitors, antibacterial agents, metal deactivators, wetting agents, antifoaming agents, surfactants, reinforcing agents, plasticizers, lubricants, antifogging agents, anticorrosion agents, pigment dispersants, flow control agents, peroxide decomposers, mold decolorizing agents, fluorescent brighteners, organic flame retardants, inorganic flame retardants, anti-dripping agents, melt flow modifiers, antistatic agents, anti-algae agents, anti-fungal agents, flame retardants, slip agents, metal chelating agents, anti-blocking agents, heat stabilizers, processing stabilizers, dispersants, thickeners, rheology control agents, foaming agents, antioxidants, preservatives, antistatic agents, silane coupling agents, antioxidants, and film-forming aids, but the present invention is not limited to these examples. These additives may be used alone or in combination of two or more. The amounts of these additives vary depending on the type of additive and cannot be determined in general terms, so it is preferable to determine them appropriately depending on the type of additive.

[0093] [Method for producing an aqueous dispersion containing core-shell particles] The core-shell particle-containing aqueous dispersion according to the present disclosure can be obtained through the following steps. (1) Step 1: mixing a colorant, a monomer A, a fatty acid ester, a nonionic surfactant, and an aqueous medium, heating the resulting mixture under stirring to a temperature equal to or higher than the phase inversion onset temperature of the mixture and lower than the boiling point of the aqueous medium, and then cooling the mixture to a temperature lower than the phase inversion onset temperature of the mixture; (2) Step 2, after Step 1, of polymerizing monomer A; (3) Step 3: After step 2, a visible light absorber and monomer B are added, and monomer B is polymerized. In step 1 of the present disclosure, a colorant, a monomer A constituting polymer A, a nonionic surfactant, and an aqueous medium are mixed, and the resulting mixture is heated under stirring to a temperature equal to or higher than the phase inversion onset temperature of the mixture and lower than the boiling point of the aqueous medium, and then the mixture is cooled to a temperature lower than the phase inversion onset temperature of the mixture.

[0094] The colorant used in step 1 and the monomer A constituting the polymer A are as described above.

[0095] When preparing the core-shell particle-containing aqueous dispersion of the present disclosure, first, a colorant, monomer A, fatty acid ester, nonionic surfactant, and aqueous medium are mixed together.

[0096] The fatty acid ester of the present disclosure is preferably an ester of a fatty acid and a monohydric alcohol. The fatty acid residue forming the fatty acid ester may be a fatty acid having 1 to 25 carbon atoms, and the alkyl ester moiety derived from the monohydric alcohol may have 5 to 25 carbon atoms.

[0097] The fatty acid ester of the present disclosure may be a fatty acid ester having 15 or more carbon atoms, specifically, the fatty acid residue may have 15 or more carbon atoms, or the alkyl ester moiety may have 15 or more carbon atoms, and it is more preferable that the total carbon number of the compound is 15 or more. From the viewpoint of improving the dispersion stability of the core-shell particle-containing aqueous dispersion, the lower limit of the carbon number of the fatty acid ester having 15 or more carbon atoms is 15 or more, preferably 18 or more, and more preferably 22 or more, and the upper limit is not particularly limited, but is preferably 60 or less, more preferably 50 or less, and even more preferably 40 or less, from the viewpoint of easy availability of raw materials.

[0098] The fatty acid ester having 15 or more carbon atoms may have a polymerizable unsaturated double bond. Although the fatty acid ester having 15 or more carbon atoms and a polymerizable unsaturated double bond has a polymerizable unsaturated double bond, it is not included in the monofunctional monomer.

[0099] Examples of fatty acid esters having 15 or more carbon atoms include fatty acid esters having an alkyl ester moiety with a polymerizable unsaturated double bond and a carbon number of 14 or more, such as tetradecyl (meth)acrylate, hexadecyl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, eicosyl (meth)acrylate, and 2-decyltetradecyl (meth)acrylate; fatty acid esters having an alkyl ester moiety with a carbon number of 14 or more, such as hexadecyl 2-ethylhexanoate, myristyl myristate, stearyl myristate, stearyl 2-ethylhexanoate, and stearyl stearate; and fatty acid esters having an alkyl group with a carbon number of 14 or more, such as ethyl myristate, isopropyl myristate, butyl myristate, ethyl palmitate, ethyl stearate, and 2-ethylhexyl stearate. However, the present invention is not limited to these examples. These fatty acid esters may be used alone or in combination of two or more. Among fatty acid esters having 15 or more carbon atoms, fatty acid esters having 14 or more carbon atoms in the alkyl ester moiety are preferred from the viewpoint of improving the dispersion stability of the core-shell particle-containing aqueous dispersion, and hexadecyl 2-ethylhexanoate, myristyl myristate, stearyl myristate, stearyl 2-ethylhexanoate, and stearyl stearate are more preferred.

[0100] The amount of the fatty acid ester used in step 1 is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, even more preferably 10 parts by mass or more, particularly preferably 15 parts by mass or more, and is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 35 parts by mass or less, particularly preferably 30 parts by mass or less, relative to 100 parts by mass of the total amount of the colorant and the monomer A.

[0101] Examples of nonionic surfactants of the present disclosure include polyoxyethylene alkyl ethers, polyoxyethylene alkylaryl ethers, condensates of polyethylene glycol and polypropylene glycol, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, fatty acid monoglycerides, condensation products of ethylene oxide and aliphatic amines, allyloxymethylalkoxyethylhydroxypolyoxyethylene, polyoxyalkylene alkenyl ethers, and the like; however, the present invention is not limited to these examples.

[0102] The HLB (hydrophilic-lipophilic balance) of the nonionic surfactant of the present disclosure is preferably 8 or more, more preferably 9 or more, and even more preferably 10 or more, from the viewpoint of improving the dispersion stability of the core particle-containing aqueous dispersion. It is preferably 17 or less, more preferably 16 or less, and even more preferably 15 or less, from the viewpoint of improving the dispersion stability of the core particle-containing aqueous dispersion. The HLB of the nonionic surfactant is preferably 14 or less, more preferably 13.5 or less, and even more preferably 13 or less, from the viewpoint of obtaining a core particle-containing aqueous dispersion containing core particles having a fine particle size. Therefore, the HLB of the nonionic surfactant is preferably 8 to 17, more preferably 9 to 16, even more preferably 9 to 15, even more preferably 10 to 14, even more preferably 10 to 13.5, and particularly preferably 10 to 13. The HLB of the nonionic surfactant is calculated based on the Griffin method using the following formula: [HLB of nonionic surfactant] = 20 × [(molecular weight of hydrophilic part) / (molecular weight of surfactant)] This is the value calculated by

[0103] Examples of nonionic surfactants include ester-type nonionic surfactants such as polyglycerin fatty acid esters and sucrose fatty acid esters, ethylene-propylene block copolymer-type nonionic surfactants, alkyl ether-type nonionic surfactants, phenol-type nonionic surfactants, and amide-type nonionic surfactants, but the present invention is not limited to these examples. These surfactants may be used alone or in combination of two or more.

[0104] Nonionic surfactants are readily available commercially. Examples of commercially available nonionic surfactants include those manufactured by Kao Corporation under the trade name Latemul PD-420 (HLB: 12.6), those manufactured by Nippon Shokubai Co., Ltd. under the trade name Softanol 120 (HLB: 14.5), and those manufactured by ADEKA Corporation under the trade name Adeka Reasop ER-10 (HLB: 12.1), but the present invention is not limited to these examples.

[0105] Among nonionic surfactants, it is preferable to use a reactive nonionic surfactant from the viewpoint of incorporating the nonionic surfactant into the core particles. Reactive nonionic surfactants are readily available commercially. Examples of commercially available reactive nonionic surfactants include ADEKA CORPORATION (trade name: ADEKA REASOAP ER-10 (HLB: 12.1)) and Kao CORPORATION (trade name: LATEMURU PD-420 (HLB: 12.6)), but the present invention is not limited to these examples.

[0106] The content of the nonionic surfactant of the present disclosure is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, and even more preferably 10% by mass or more, based on the total amount of the colorant, monomer A, fatty acid ester, and nonionic surfactant, from the viewpoint of improving the dispersion stability of the core particle-containing aqueous dispersion, and is preferably 60% by mass or less, more preferably 50% by mass or less, from the viewpoint of improving the dispersion stability of the monomer emulsion particle-containing aqueous dispersion.

[0107] When a surfactant is used in step 1, other emulsifiers such as anionic emulsifiers, cationic emulsifiers, and amphoteric emulsifiers may also be included within the scope that does not impair the object of the present invention.

[0108] Examples of aqueous media in the present disclosure include water and mixed solvents of water and water-soluble organic solvents. Examples of water-soluble organic solvents include lower alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, and tert-butyl alcohol; polyhydric alcohols such as ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, and diethylene glycol; and ketones such as acetone and methyl ethyl ketone, but the present invention is not limited to these examples. These aqueous media may be used alone or in combination of two or more. From the viewpoint of improving the dispersion stability of the core-shell particle-containing aqueous dispersion, the water content in the aqueous medium is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and even more preferably 80% by mass or more, with the upper limit of this content being 100% by mass. Among aqueous media, water is preferred.

[0109] The mass ratio of the total of the colorant and monomer A to the aqueous medium (monomer A / aqueous medium) is preferably 5 / 95 to 50 / 50, more preferably 10 / 90 to 45 / 55, and even more preferably 15 / 85 to 40 / 60, from the viewpoint of uniformly dispersing the monomer A in the aqueous medium.

[0110] The temperature at which the total of the colorant and monomer A is mixed with the aqueous medium cannot be determined in general because it varies depending on factors such as the phase inversion temperature described below, but is typically preferably 5 to 45°C, more preferably 5 to 40°C, and even more preferably 5 to 35°C. When mixing monomer A with the aqueous medium, it is preferable to add monomer A to the aqueous medium under stirring in order to uniformly disperse the monomer component in the aqueous medium. There is no need to use specialized equipment, such as a conventional high-viscosity paint mixer or high-pressure homogenizer, to stir the aqueous medium; for example, simple stirring equipment such as a stirring rod or magnetic stirrer can be used to uniformly disperse monomer A in the aqueous medium.

[0111] Next, after mixing the monomer A with the aqueous medium, the resulting mixture is heated with stirring to a temperature equal to or higher than the phase inversion onset temperature of the mixture but lower than the boiling point of the aqueous medium, and then cooled with stirring to a temperature lower than the phase inversion onset temperature. In the present invention, this procedure is adopted, so that a core particle-containing aqueous dispersion containing the colorant and the monomer A and having excellent dispersion stability can be obtained.

[0112] The phase inversion temperature of the mixture can be determined using the electrical conductivity in the reaction vessel. The phase inversion onset temperature is the temperature at which the electrical conductivity begins to decrease continuously with increasing temperature, and the phase inversion end temperature is the temperature at which the electrical conductivity falls to 1.00 μS or less. If the electrical conductivity does not fall to 1.00 μS or less even when the upper limit of the measurable temperature of the conductivity meter is exceeded, the temperature at which the appearance of the mixture does not change even after 3 minutes or more have passed since the mixture reached a temperature higher than the phase inversion onset temperature under stirring is taken as the end point of the phase inversion temperature. Specifically, it can be measured by the method described in the Examples.

[0113] Of the phase inversion temperatures, the phase inversion starting temperature is preferably 35° C. or higher, more preferably 45° C. or higher, and even more preferably 50° C. or higher, from the viewpoint of improving the dispersion stability of the core particle-containing aqueous dispersion. Moreover, the phase inversion ending temperature is preferably 98° C. or lower, more preferably 97° C. or lower, and even more preferably 96° C. or lower, from the viewpoint of improving the emulsion stability.

[0114] The atmosphere in which the mixture is heated is not particularly limited, but from the viewpoint of avoiding the influence of oxygen contained in the air, it is preferable to use an inert gas such as nitrogen gas or argon gas.

[0115] The lower limit of the heating temperature (maximum temperature when heated) of the mixture is a temperature equal to or higher than the phase inversion start temperature of the mixture, from the viewpoint of improving the dispersion stability of the emulsion particle-containing aqueous dispersion, but is preferably a temperature 0.5°C or higher than the phase inversion start temperature of the mixture, and more preferably a temperature 1°C or higher than the phase inversion start temperature of the mixture. Furthermore, the lower limit of the heating temperature (maximum temperature when heated) of the mixture is preferably a temperature equal to or higher than the phase inversion end temperature of the mixture, and more preferably 0.5°C or higher than the phase inversion end temperature of the mixture, from the viewpoint of improving the dispersion stability of the core particle-containing aqueous dispersion.

[0116] The upper limit of the heating temperature (maximum temperature when heated) of the mixture is usually a temperature below the boiling point of the aqueous medium, preferably a temperature that is 3°C or more lower than the boiling point of the aqueous medium, and more preferably a temperature that is 5°C or more lower than the boiling point of the aqueous medium.

[0117] Next, after the temperature of the mixture reaches a temperature equal to or higher than the phase inversion starting temperature of the mixture and lower than the boiling point of the aqueous medium, the mixture is cooled to a temperature equal to or lower than the phase inversion temperature of the mixture.

[0118] There are no particular limitations on the means for cooling the mixture. The mixture may be cooled, for example, by standing to cool or by air cooling. The mixture is cooled to a temperature equal to or lower than the phase inversion onset temperature of the mixture. The mixture is preferably cooled to a temperature 10°C or more lower than the phase inversion onset temperature of the mixture, more preferably 20°C or more lower than the phase inversion onset temperature of the mixture, even more preferably 25°C or more lower than the phase inversion onset temperature of the mixture, and even more preferably 30°C or more lower than the phase inversion onset temperature of the mixture.

[0119] By the above operations, an aqueous dispersion containing core particles having a fine particle size can be obtained.

[0120] In step 2 of the present disclosure, after step 1, monomer A is polymerized to obtain polymer A. Examples of a method for polymerizing monomer A include emulsion polymerization, in which a surfactant is dissolved in the emulsion particle-containing aqueous dispersion and a polymerization initiator is added to the resulting solution, but the present invention is not limited to only this method.

[0121] Examples of surfactants include anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, and polymer surfactants. These surfactants may be used alone or in combination of two or more types. However, it is preferable to use an additional surfactant in addition to the surfactant used in step 1, and it is even more preferable to use an anionic surfactant as the additional surfactant.

[0122] Examples of anionic surfactants include alkyl sulfate salts such as ammonium dodecyl sulfate and sodium dodecyl sulfate; alkyl sulfonate salts such as ammonium dodecyl sulfonate, sodium dodecyl sulfonate and sodium alkyl diphenyl ether disulfonate; alkyl aryl sulfonate salts such as ammonium dodecyl benzene sulfonate and sodium dodecyl naphthalene sulfonate; polyoxyethylene alkyl sulfonate salts; polyoxyethylene alkyl sulfate salts; polyoxyethylene alkyl aryl sulfate salts; dialkyl sulfosuccinate salts; aryl sulfonic acid-formalin condensates; fatty acid salts such as ammonium laurate and sodium stearylate; sulfates or salts thereof having an allyl group such as bis(polyoxyethylene polycyclic phenyl ether) methacrylate sulfonate salts, propenyl-alkyl sulfosuccinate ester salts, (meth)acrylic acid polyoxyethylene sulfonate salts, (meth)acrylic acid polyoxyethylene phosphonate salts, and sulfonate salts of allyloxymethyl alkyloxy polyoxyethylene; sulfate salts of allyloxymethyl alkoxyethyl polyoxyethylene, and polyoxyalkylene alkenyl ether ammonium sulfate salts, but the present invention is not limited to these examples.

[0123] Examples of the nonionic surfactant include the compounds described above.

[0124] Examples of cationic emulsifiers include alkylammonium salts such as dodecylammonium chloride, but the present invention is not limited to these examples.

[0125] Examples of amphoteric surfactants include betaine ester emulsifiers, but the present invention is not limited to these examples.

[0126] Examples of polymer surfactants include poly(meth)acrylates such as sodium polyacrylate; polyvinyl alcohol; polyvinylpyrrolidone; polyhydroxyalkyl(meth)acrylates such as polyhydroxyethyl acrylate; and copolymers containing one or more of the monomers that make up these polymers as copolymerization components, but the present invention is not limited to these examples.

[0127] Among the surfactants, emulsifiers having a polymerizable group, i.e., so-called reactive surfactants, are preferred from the viewpoint of improving weather resistance, and non-nonylphenyl surfactants are preferred from the viewpoint of environmental protection.

[0128] Examples of reactive surfactants include propenyl-alkyl sulfosuccinate salts, (meth)acrylic acid polyoxyethylene sulfonate salts, (meth)acrylic acid polyoxyethylene phosphonate salts (e.g., Sanyo Chemical Industries, Ltd., trade name: Eleminol RS-30, etc.), polyoxyethylene alkylpropenylphenyl ether sulfonate salts (e.g., Dai-ichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10, Aqualon HS-10, etc.), sulfonate salts of allyloxymethyl alkyloxypolyoxyethylene (e.g., Dai-ichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon KH-10, etc.), sulfonate salts of allyloxymethyl nonylphenoxyethyl hydroxypolyoxyethylene (e.g., ADEKA Corporation, trade name: Adeka Reasoap SE-10, etc.), allyloxymethyl alkoxyethyl Examples of suitable hydroxypolyoxyethylene sulfate salts include arylhydroxypolyoxyethylene sulfate salts (e.g., manufactured by ADEKA CORPORATION under the trade names ADEKA REASOAP SR-10 and SR-30), bis(polyoxyethylene polycyclic phenyl ether) methacrylated sulfonate salts (e.g., manufactured by Nippon Nyukazai Co., Ltd. under the trade name ANTOX MS-60), allyloxymethylalkoxyethylhydroxypolyoxyethylene (e.g., manufactured by ADEKA CORPORATION under the trade name ADEKA REASOAP ER-20), polyoxyethylene alkylpropenylphenyl ether (e.g., manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. under the trade name AQUALON RN-20), and allyloxymethylnonylphenoxyethylhydroxypolyoxyethylene (e.g., manufactured by ADEKA CORPORATION under the trade name ADEKA REASOAP NE-10). However, the present invention is not limited to these examples.

[0129] When polymerizing the monomer A, the amount of the surfactant added in step 2 per 100 parts by mass of the monomer A is preferably 0.3 parts by mass or more, more preferably 0.5 parts by mass or more, from the viewpoint of improving polymerization stability, and is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 5 parts by mass or less, from the viewpoint of improving weather resistance.

[0130] When a nonionic surfactant is used in step 1 and an anionic surfactant is used in step 2, the mass ratio of the nonionic surfactant to the anionic surfactant is preferably 99 / 1 to 60 / 40, more preferably 97 / 3 to 70 / 30, and even more preferably 96 / 4 to 80 / 20.

[0131] Examples of polymerization initiators include azo compounds such as azobisisobutyronitrile, 2,2-azobis(2-methylbutyronitrile), 2,2-azobis(2,4-dimethylvaleronitrile), 2,2-azobis(2-diaminopropane) hydrochloride, 4,4-azobis(4-cyanovaleric acid), 2,2-azobis(2-methylpropionamidine), and 2,2-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride; persulfates such as ammonium persulfate and potassium persulfate; and peroxides such as hydrogen peroxide, benzoyl peroxide, parachlorobenzoyl peroxide, lauroyl peroxide, and ammonium peroxide, but the present invention is not limited to these examples. These polymerization initiators may be used alone or in combination of two or more.

[0132] The amount of the polymerization initiator is preferably 0.03 parts by mass or more, more preferably 0.04 parts by mass or more, per 100 parts by mass of the monomer A, from the viewpoint of increasing the polymerization rate and reducing the amount of unreacted monomer remaining, and is preferably 2 parts by mass or less, more preferably 1 part by mass or less, from the viewpoint of improving weather resistance.

[0133] The method for adding the polymerization initiator is not particularly limited, and examples of the addition method include batch addition, divided addition, and continuous dropwise addition.

[0134] In order to promote the decomposition of the polymerization initiator, a suitable amount of a decomposer for the polymerization initiator, such as a reducing agent such as sodium hydrogen sulfite or a transition metal salt such as ferrous sulfate, may be added to the reaction system.

[0135] A chain transfer agent can be used to adjust the weight-average molecular weight of polymer A. Examples of chain transfer agents include 2-ethylhexyl thioglycolate, tert-dodecyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, mercaptoacetic acid, mercaptopropionic acid, 2-mercaptoethanol, α-methylstyrene, and α-methylstyrene dimer, but the present invention is not limited to these examples. These chain transfer agents may be used alone or in combination of two or more. The amount of chain transfer agent per 100 parts by mass of monomer is preferably 0.01 to 10 parts by mass from the viewpoint of adjusting the weight-average molecular weight of the polymer contained in the emulsion particles.

[0136] Furthermore, from the viewpoint of improving weather resistance, an appropriate amount of a silane coupling agent may be used when emulsion polymerizing the monomer A. Examples of the silane coupling agent include silane coupling agents having a polymerizable unsaturated bond such as a (meth)acryloyl group, a vinyl group, an allyl group, or a propenyl group, but the present invention is not limited to these examples.

[0137] When the monomer A is emulsion polymerized, an appropriate amount of additives such as a chelating agent, a film-forming agent, a pH buffering agent, etc. may be added to the reaction system, if necessary.

[0138] The atmosphere in which the monomer A is emulsion polymerized is not particularly limited, but from the viewpoint of increasing the efficiency of the polymerization initiator, an inert gas such as nitrogen gas or argon gas is preferred.

[0139] The polymerization temperature when emulsion polymerizing the monomer A is not particularly limited, but is usually preferably 50 to 100° C., more preferably 60 to 85° C. The polymerization temperature may be constant or may be changed during the polymerization reaction.

[0140] The polymerization time for the monomer A is not particularly limited and may be set appropriately depending on the progress of the polymerization reaction, but is usually about 2 to 9 hours.

[0141] In step 3 of the present disclosure, after step 2, a visible light absorbent and a monomer B constituting polymer B are added, and monomer B is polymerized.

[0142] The visible light absorbent and the monomer B constituting the polymer B are as described above.

[0143] Examples of a method for polymerizing monomer B include emulsion polymerization, in which a surfactant is dissolved in the core particle-containing aqueous dispersion obtained in step 2 and a polymerization initiator is added to the resulting solution; however, the present invention is not limited to such a method.

[0144] Examples of surfactants include anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, and polymer surfactants. These surfactants may be used alone or in combination of two or more. The amount of surfactant used when emulsion polymerizing monomer B is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, even more preferably 1.5 parts by mass or more, and even more preferably 2 parts by mass or more, relative to 100 parts by mass of monomer B, from the viewpoint of improving polymerization stability, and is preferably 10 parts by mass or less, more preferably 6 parts by mass or less, even more preferably 5.5 parts by mass or less, and even more preferably 5 parts by mass or less, from the viewpoint of improving weather resistance.

[0145] Examples of polymerization initiators include azo compounds such as azobisisobutyronitrile, 2,2-azobis(2-methylbutyronitrile), 2,2-azobis(2,4-dimethylvaleronitrile), 2,2-azobis(2-diaminopropane) hydrochloride, 4,4-azobis(4-cyanovaleric acid), 2,2-azobis(2-methylpropionamidine), and 2,2-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride; persulfates such as ammonium persulfate and potassium persulfate; and peroxides such as hydrogen peroxide, benzoyl peroxide, parachlorobenzoyl peroxide, lauroyl peroxide, and ammonium peroxide, but the present invention is not limited to these examples. These polymerization initiators may be used alone or in combination of two or more.

[0146] The amount of polymerization initiator per 100 parts by mass of monomer B is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, from the viewpoint of increasing the polymerization rate and reducing the amount of remaining unreacted monomer, and is preferably 1 part by mass or less, more preferably 0.5 parts by mass or less, from the viewpoint of improving weather resistance.

[0147] The method for adding the polymerization initiator is not particularly limited. Examples of the addition method include batch addition, divided addition, continuous dropwise addition, etc. In order to hasten the completion of the polymerization reaction, a portion of the polymerization initiator may be added before or after the completion of the addition of the monomer components for forming the resin layer into the reaction system.

[0148] In order to promote the decomposition of the polymerization initiator, a suitable amount of a decomposer for the polymerization initiator, such as a reducing agent such as sodium hydrogen sulfite or a transition metal salt such as ferrous sulfate, may be added to the reaction system.

[0149] The chain transfer agent can be used to adjust the weight average molecular weight of polymer B. The amount of chain transfer agent per 100 parts by mass of monomer B is preferably 0.01 to 10 parts by mass from the viewpoint of adjusting the weight average molecular weight of the polymer emulsion particles.

[0150] When the monomer B is emulsion polymerized, a suitable amount of a silane coupling agent may be used from the viewpoint of improving the weather resistance of the polymer emulsion particles. Examples of the silane coupling agent include silane coupling agents having a polymerizable unsaturated bond such as a (meth)acryloyl group, a vinyl group, an allyl group, or a propenyl group, but the present invention is not limited to these examples.

[0151] When emulsion polymerizing the monomer B, additives such as a chelating agent, a film-forming aid, a pH buffer, etc. may be added to the reaction system as needed. The amount of the additive varies depending on the type of additive and cannot be determined in general, but is usually preferably about 0.01 to 5 parts by mass, more preferably about 0.1 to 3 parts by mass, per 100 parts by mass of the monomer B.

[0152] The atmosphere in which polymer B is emulsion polymerized is not particularly limited, but from the viewpoint of increasing the efficiency of the polymerization initiator, it is preferably an inert gas such as nitrogen gas.

[0153] The polymerization temperature for polymer B is not particularly limited, but is usually preferably 50 to 100° C., more preferably 60 to 85° C. The polymerization temperature may be constant or may be changed during the polymerization reaction.

[0154] The polymerization time for emulsion polymerization of polymer B is not particularly limited and may be appropriately set depending on the progress of the polymerization reaction, but is usually about 2 to 9 hours.

[0155] As described above, an aqueous dispersion containing core-shell particles can be obtained by emulsion polymerizing polymer B. The thickness of polymer B that forms the shell layer of the core-shell particles cannot be determined in general because it varies depending on the application, but is usually about 2 to 50 nm.

[0156] The mass ratio of the core layer to the shell layer of the core-shell particle of the present disclosure is generally preferably 5 / 95 to 80 / 20, and more preferably 10 / 90 to 75 / 25.

[0157] In the core-shell particles of the present disclosure, the mass ratio of polymer A to polymer B is usually preferably 5 / 95 to 80 / 20, more preferably 10 / 90 to 75 / 25.

[0158] In the core-shell particles of the present disclosure, the mass ratio of the total amount of the colorant and polymer A to the total amount of the visible light absorbing material and polymer B is usually preferably 5 / 95 to 80 / 20, more preferably 10 / 90 to 75 / 25.

[0159] The core-shell particle-containing aqueous dispersion of the present disclosure may contain, for example, additives, etc., to the extent that the object of the present invention is not impaired. Examples of additives include those described above. The amount of additive varies depending on the type of additive and cannot be determined in general. Therefore, it is preferable to determine the amount appropriately depending on the type of additive.

[0160] The nonvolatile content of the aqueous dispersion in the present disclosure is preferably 20% by mass or more, more preferably 25% by mass or more, from the viewpoint of improving productivity, and is preferably 70% by mass or less, more preferably 60% by mass or less, from the viewpoint of improving handleability. Therefore, the nonvolatile content of the core-shell particle-containing aqueous dispersion is preferably 20 to 70% by mass, more preferably 25 to 60% by mass.

[0161] In this specification, the amount of nonvolatile content in the aqueous dispersion is determined by weighing 1 g of the aqueous dispersion, drying it in a hot air dryer at a temperature of 110°C for 1 hour, and taking the resulting residue as the nonvolatile content, and calculating it using the formula: [Nonvolatile content in aqueous dispersion (mass%)] = ([mass of residue] ÷ [1 g of aqueous resin dispersion]) × 100 This means the value calculated based on

[0162] The core-shell particle-containing aqueous dispersion of the present disclosure can be imparted with crosslinking properties by adding a crosslinking agent. The crosslinking agent may be one that initiates a crosslinking reaction at room temperature or one that initiates a crosslinking reaction by heat. Examples of the crosslinking agent include oxazoline group-containing compounds, isocyanate group-containing compounds, and aminoplast resins. These crosslinking agents may be used alone or in combination of two or more.

[0163] In the present disclosure, in addition to the above-mentioned crosslinking agents, crosslinking agents such as carbodiimide compounds; polyvalent metal compounds represented by zirconium compounds, zinc compounds, titanium compounds, aluminum compounds, etc. can be used within the scope that does not impair the object of the present invention.

[0164] The core-shell particle-containing aqueous dispersion of the present disclosure may also contain an appropriate amount of additives, such as a film-forming aid, a plasticizer, a foam inhibitor, a pigment, a thickener, a matting agent, a dispersant, a wetting agent, an ultraviolet absorber, an ultraviolet stabilizer, a filler, a leveling agent, a stabilizer, a pigment, a dye, or an antioxidant, within a range that does not impair the object of the present invention.

[0165] Furthermore, any of the core-shell particle-containing aqueous dispersions of the present disclosure can be suitably used, for example, in aqueous paints, which contain the aqueous resin dispersions.

[0166] The aqueous paint may be composed only of an aqueous resin dispersion, or may contain, within the scope of the object of the present invention, one or more of, for example, a film-forming aid, a plasticizer, a foam inhibitor, a pigment, a thickener, a matting agent, a dispersant, a wetting agent, an ultraviolet absorber, an ultraviolet stabilizer, a filler, a leveling agent, a stabilizer, a pigment, a dye, an antioxidant, etc. Examples of aqueous paints include enamel paints and clear paints.

[0167] The water-based paint may be applied alone in a single layer, or may be applied by overcoating two or more layers. When overcoating two or more layers, only some of the layers may be formed with the water-based paint, or all of the layers may be formed with the water-based paint. Examples of overcoating methods include applying a paint for a first layer (e.g., an undercoat layer) to a substrate that has been treated with a primer or a sealer, drying the paint, and then overcoating a paint for a second layer (e.g., a topcoat layer) and drying the paint, but the present invention is not limited to such a method.

[0168] Examples of methods for applying the water-based paint include application methods using a brush, a bar coater, an applicator, an air spray, an airless spray, a roll coater, a flow coater, etc., but the present invention is not limited to these examples.

[0169] Water-based paints can be suitably used for painting, for example, the exterior walls of buildings and automobile bodies, as well as for inorganic building materials such as ceramic building materials. Examples of ceramic building materials include roof tiles and exterior wall materials. Ceramic building materials are obtained by adding inorganic fillers, fibrous materials, etc. to a hydraulic adhesive, which is the raw material for the inorganic hardened body, molding the resulting mixture, and curing and hardening the resulting molded body. Examples of inorganic building materials that constitute the exterior of buildings include flexible boards, calcium silicate boards, gypsum slag perlite boards, wood chip cement boards, precast concrete boards, ALC boards, and gypsum boards.

[0170] Furthermore, the water-based paint of the present invention can be overcoated on a coating film of an oil-based paint, and it is also possible to overcoat a coating film of an oil-based paint on a coating film of the water-based paint of the present invention. When an oil-based paint is overcoated on a coating film of the water-based paint of the present invention from the viewpoint of weather resistance, it is particularly preferable to use an oil-based paint containing an ultraviolet absorber, and if necessary, an antioxidant, a light stabilizer, or a dye may be added.

[0171] Other examples include automobiles, automobile parts (for example, bodies made of various materials, bumpers, spoilers, mirrors, wheels, interior materials, etc.), metal plates such as steel plates, motorcycles, motorcycle parts, road materials (for example, guardrails, traffic signs, soundproof walls, etc.), tunnel materials (for example, sidewall panels, etc.), ships, railway vehicles, aircraft, furniture, musical instruments, home appliances, building materials, containers, office supplies, sporting goods, toys, etc.

[0172] The composition is particularly useful as a vehicle paint. [Example]

[0173] The present invention will now be described in more detail based on examples, but the present invention is not limited to these examples.

[0174] In the following examples and comparative examples, unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass".

[0175] In the following examples and comparative examples, the abbreviations for each compound mean the following compounds. MMA: Methyl methacrylate EHA: 2-Ethylhexyl acrylate CHMA: Cyclohexyl methacrylate St: Styrene ·VP: n-vinylpyrrolidone LMA: Lauryl methacrylate 1,6HXA: 1,6-hexanediol diacrylate KBM-503: Methacryloxypropyltrimethoxysilane C22A: Behenyl acrylate EHC: hexadecyl 2-ethylhexanoate CS-12: 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate CS-16: 2,2,4-trimethyl-1,3-pentanediol diisobutyrate HEMA: 2-hydroxyethyl methacrylate

[0176] Manufacturing Example 1 A reaction vessel equipped with a stirrer, a temperature sensor, a condenser, a nitrogen inlet tube, and a dropping funnel was charged with 67 parts of deionized water, 10.9 parts of a polyoxyalkylene alkenyl ether (manufactured by Kao Corporation, trade name: LATEMULL PD-420, HLB: 12.6) as a nonionic emulsifier, 3.0 parts of MMA, 7.0 parts of CHMA, 0.4 parts of St, 0.3 parts of 1,6HXA, 4.1 parts of EHC, 3.0 parts of an ultraviolet absorber (manufactured by BASF, trade name: Tinuvin® 400), 3.0 parts of an ultraviolet absorber (manufactured by BASF, trade name: Tinuvin® 479), 0.3 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adeka STAB LA-87), and 1.0 part of an oil-soluble chromium complex salt red dye. A portion of the resulting mixture was removed, and the phase inversion temperature of the mixture was measured by the following method. As a result, the phase inversion temperature was 76 to 83°C.

[0177] [Method for measuring phase inversion temperature] A 2 L (liter) reaction vessel was equipped with a stirring device and a temperature sensor, and 1000 g of the mixture was placed in the reaction vessel and stirred.

[0178] The reaction vessel was heated in a water bath, and the electrical conductivity was measured every time the temperature of the mixture in the reaction vessel increased by 1°C using a conductivity meter (manufactured by EUTECH, trade name: Lacom Tester PC450).

[0179] The electrical conductivity was plotted for each temperature increase, and the temperature at which the electrical conductivity began to decrease continuously with increasing temperature was taken as the phase inversion starting temperature, and the temperature at which the electrical conductivity became 1.00 μS or less was taken as the phase inversion end temperature.

[0180] In addition, if the electrical conductivity did not become 1.00 μS or less even when the upper limit of the measurable temperature of the conductivity meter was exceeded, the temperature at which the appearance of the mixture did not change even after 3 minutes or more had passed since it reached a temperature higher than the phase inversion starting temperature under stirring was taken as the end point of the phase inversion temperature.

[0181] After measuring the phase inversion temperature of the mixture, the reaction vessel was heated in a water bath under stirring while nitrogen gas was introduced into the reaction vessel.

[0182] After the internal temperature of the reaction vessel reached 86°C, the reaction vessel was removed from the water bath and air-cooled with stirring until the internal temperature reached 40°C or lower, thereby obtaining an aqueous dispersion containing monomer emulsion particles.

[0183] The dispersion stability of the aqueous dispersion containing the monomer emulsion particles obtained above and the average particle size of the monomer emulsion particles were examined by the following methods. The results are shown in Table 1.

[0184] (1) Dispersion stability The dispersion state of the monomer emulsion particles after the aqueous dispersion containing the monomer emulsion particles was allowed to stand at room temperature (approximately 25°C) for 12 hours, and the dispersion state of the monomer emulsion particles after the aqueous dispersion containing the monomer emulsion particles was allowed to stand at room temperature (approximately 25°C) for 14 days were each visually observed, and the dispersion stability of the aqueous dispersion containing the monomer emulsion particles was evaluated based on the following evaluation criteria. [Evaluation criteria] ◯: No precipitation of monomer emulsion particles or separation of the monomer component from the aqueous medium was observed. ×: At least one of precipitation of monomer emulsion particles and separation of the monomer component from the aqueous medium is observed.

[0185] (2) Average particle size Using a multi-analyte nanoparticle size measurement system (manufactured by Otsuka Electronics Co., Ltd., product name: nanoSAQRA), which is a particle size measurement device using a dynamic light scattering method, the average particle size (hereinafter simply referred to as the average particle size) obtained by cumulant analysis of the monomer emulsion particles immediately after production and the average particle size of the monomer emulsion particles after being left to stand for 14 days after production were measured.

[0186] Next, 100 parts of the monomer emulsion particle-containing aqueous dispersion obtained above was placed in a reaction vessel, and 2.6 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, product name: ADEKA REASOAP SR-20) was added to the reaction vessel. The mixture was stirred at room temperature for 30 minutes while introducing nitrogen gas into the reactor, and then the reaction vessel was placed in a water bath and heated in the water bath with stirring until the internal temperature of the reaction vessel reached 72°C.

[0187] Then, 0.9 parts of a 5% aqueous potassium persulfate solution was added to the reaction vessel, and the reaction was carried out at an internal temperature of 72°C for 1 hour. After that, the contents of the reaction vessel were heated with stirring at an internal temperature of 80°C for 5 hours, thereby polymerizing the monomers contained in the monomer emulsion particles and obtaining an aqueous dispersion containing polymer emulsion particles.

[0188] The average particle size of the polymer emulsion particles contained in the aqueous dispersion containing the polymer emulsion particles obtained above was measured in the same manner as above, and the result was that the average particle size of the polymer emulsion particles was 51 nm.

[0189] Manufacturing Example 2 A reaction vessel equipped with a stirrer, temperature sensor, condenser, nitrogen inlet tube, and dropping funnel was charged with 67 parts of deionized water, 10.8 parts of a polyoxyalkylene alkenyl ether (manufactured by Kao Corporation, trade name: LATEMURU PD-420, HLB: 12.6) as a nonionic emulsifier, 3.0 parts of MMA, 10.4 parts of CHMA, 0.6 parts of 1,6HXA, 0.7 parts of KBM-503, 3.5 parts of EHC, 2.6 parts of an ultraviolet absorber (manufactured by BASF, trade name: Tinuvin® 400), 1.3 parts of an oil-soluble azo-based red dye, and 0.1 parts of an oil-soluble chromium complex salt-based black dye (manufactured by Orient Chemical Industries Co., Ltd., trade name: VALIFAST BLACK 3810). A portion of the resulting mixture was removed, and the phase inversion temperature of the mixture was measured in the same manner as in Production Example 1. As a result, the phase inversion temperature was 75 to 79 ° C.

[0190] After measuring the phase inversion temperature of the mixture, the reaction vessel was heated in a water bath under stirring while nitrogen gas was introduced into the reaction vessel.

[0191] After the internal temperature of the reaction vessel reached 83°C, the reaction vessel was removed from the water bath and air-cooled with stirring until the internal temperature reached 40°C or less, thereby obtaining an aqueous dispersion containing monomer emulsion particles.

[0192] The dispersion stability of the obtained aqueous dispersion containing monomer emulsion particles and the average particle size of the monomer emulsion particles were examined in the same manner as in Production Example 1. The results are shown in Table 1.

[0193] Next, 100 parts of the monomer emulsion particle-containing aqueous dispersion obtained above was placed in a reaction vessel, and 2.6 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, product name: ADEKA REASOAP SR-20) was added to the reaction vessel. The mixture was stirred at room temperature for 30 minutes while introducing nitrogen gas into the reactor, and then the reaction vessel was placed in a water bath and heated in the water bath with stirring until the internal temperature of the reaction vessel reached 72°C.

[0194] Then, 0.9 parts of a 5% aqueous potassium persulfate solution was added to the reaction vessel, and the reaction was carried out at an internal temperature of 72°C for 1 hour. After that, the contents of the reaction vessel were heated with stirring at an internal temperature of 80°C for an additional 5 hours, thereby polymerizing the monomers contained in the monomer emulsion particles and obtaining an aqueous dispersion containing polymer emulsion particles.

[0195] The average particle size of the polymer emulsion particles contained in the aqueous dispersion containing the polymer emulsion particles obtained above was measured in the same manner as above, and the result was that the average particle size of the polymer emulsion particles was 53 nm.

[0196] Manufacturing Example 3 Into a reaction vessel equipped with a stirrer, a temperature sensor, a condenser, a nitrogen inlet tube, and a dropping funnel, 64 parts of deionized water, 10.8 parts of a polyoxyalkylene alkenyl ether (manufactured by Kao Corporation, trade name: Latemul PD-420, HLB: 12.6) as a nonionic emulsifier, 3.0 parts of MMA, 9.9 parts of CHMA, 1.5 parts of St, 0.3 parts of 1,6HXA, 4.2 parts of EHC, 2.0 parts of an ultraviolet absorber (manufactured by BASF, trade name: Tinuvin (registered trademark) 400), and 2.0 parts of an ultraviolet absorber (manufactured by BASF, trade name: Tinuvin (registered trademark) 400). 2.0 parts of Tinuvin® 479, 0.5 parts of an ultraviolet absorber (manufactured by BASF, trade name: Tinuvin® 970), 0.4 parts of an oil-soluble ultraviolet absorber (manufactured by ADEKA Corporation, trade name: Adeka STAB LA-F70), 0.3 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adeka STAB LA-87), and 1.0 part of an oil-soluble chromium complex red dye were charged, and a portion of the resulting mixture was removed and its phase inversion temperature was measured in the same manner as in Production Example 1. The resulting phase inversion temperature was 72 to 81°C.

[0197] After measuring the phase inversion temperature of the mixture, the reaction vessel was heated in a water bath under stirring while nitrogen gas was introduced into the reaction vessel.

[0198] After the internal temperature of the reaction vessel reached 85°C, the reaction vessel was removed from the water bath and air-cooled with stirring until the internal temperature reached 40°C or lower, thereby obtaining an aqueous dispersion containing monomer emulsion particles.

[0199] The dispersion stability of the obtained aqueous dispersion containing monomer emulsion particles and the average particle size of the monomer emulsion particles were examined in the same manner as in Production Example 1. The results are shown in Table 1.

[0200] Next, 100 parts of the monomer emulsion particle-containing aqueous dispersion obtained above was placed in a reaction vessel, and 2.9 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, product name: ADEKA REASOAP SR-20) was added to the reaction vessel. The mixture was stirred at room temperature for 30 minutes while introducing nitrogen gas into the reactor, and then the reaction vessel was placed in a water bath and heated in the water bath with stirring until the internal temperature of the reaction vessel reached 72°C.

[0201] Then, 1.0 parts of a 5% aqueous potassium persulfate solution was added to the reaction vessel, and the contents of the reaction vessel were reacted at an internal temperature of 72°C for 1 hour, and then heated with stirring at an internal temperature of 80°C for 5 hours, thereby polymerizing the monomers contained in the monomer emulsion particles and obtaining an aqueous dispersion containing polymer emulsion particles.

[0202] The average particle size of the polymer emulsion particles contained in the aqueous dispersion containing the polymer emulsion particles obtained above was measured in the same manner as above, and the result was that the average particle size of the polymer emulsion particles was 49 nm.

[0203] Production Example 4 Into a reaction vessel equipped with a stirrer, a temperature sensor, a condenser, a nitrogen inlet tube, and a dropping funnel, 67 parts of deionized water, 9.5 parts of polyoxyalkylene alkenyl ether as a nonionic emulsifier (manufactured by Kao Corporation, trade name: Latemul PD-420, HLB: 12.6), 3.0 parts of MMA, 12.0 parts of CHMA, 0.9 parts of St, 0.3 parts of 1,6HXA, 1.1 parts of C22A, 3.3 parts of CS-12, UV light, 1.0 part of an absorbent (manufactured by BASF, trade name: Tinuvin® 479), 0.3 parts of an oil-soluble UV absorber (manufactured by Otsuka Chemical Co., Ltd., trade name: RUVA-93), 0.3 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adekastab LA-87), 1.0 part of an oil-soluble chromium complex salt red dye, and 0.3 parts of an oil-soluble chromium complex salt black dye (manufactured by Orient Chemical Industries Co., Ltd., trade name: VALIFAST BLACK 3810) were charged, and a portion of the resulting mixture was removed, and the phase inversion temperature of the mixture was measured in the same manner as in Production Example 1. The resulting phase inversion temperature was 82 to 88°C.

[0204] After measuring the phase inversion temperature of the mixture, the reaction vessel was heated in a water bath under stirring while nitrogen gas was introduced into the reaction vessel.

[0205] After the internal temperature of the reaction vessel reached 85°C, the reaction vessel was removed from the water bath and air-cooled with stirring until the internal temperature reached 40°C or lower, thereby obtaining an aqueous dispersion containing monomer emulsion particles.

[0206] The dispersion stability of the obtained aqueous dispersion containing monomer emulsion particles and the average particle size of the monomer emulsion particles were examined in the same manner as in Production Example 1. The results are shown in Table 1.

[0207] Next, 100 parts of the monomer emulsion particle-containing aqueous dispersion obtained above was placed in a reaction vessel, and 2.9 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, product name: ADEKA REASOAP SR-20) was added to the reaction vessel. The mixture was stirred at room temperature for 30 minutes while introducing nitrogen gas into the reactor, and then the reaction vessel was placed in a water bath and heated in the water bath with stirring until the internal temperature of the reaction vessel reached 72°C.

[0208] Then, 1.0 parts of a 5% aqueous potassium persulfate solution was added to the reaction vessel, and the contents of the reaction vessel were reacted at an internal temperature of 72°C for 1 hour, and then heated with stirring at an internal temperature of 80°C for 5 hours, thereby polymerizing the monomers contained in the monomer emulsion particles and obtaining an aqueous dispersion containing polymer emulsion particles.

[0209] The average particle size of the polymer emulsion particles contained in the aqueous dispersion containing the polymer emulsion particles obtained above was measured in the same manner as above, and the result was that the average particle size of the polymer emulsion particles was 56 nm.

[0210] Production Example 5 A reaction vessel equipped with a stirrer, temperature sensor, condenser, nitrogen inlet tube, and dropping funnel was charged with 67 parts of deionized water, 10.8 parts of a polyoxyalkylene alkenyl ether (manufactured by Kao Corporation, trade name: LATEMULL PD-420, HLB: 12.6) as a nonionic emulsifier, 1.0 parts of MMA, 10.2 parts of CHMA, 3.8 parts of St, 0.3 parts of 1,6HXA, 4.5 parts of EHC, 1.5 parts of an ultraviolet absorber (manufactured by BASF, trade name: Tinuvin® 479), 0.4 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adeka STAB LA-87), and 0.5 parts of an oil-soluble blue dye (manufactured by Kiwa Chemical Industry Co., Ltd., trade name: KP Plast Blue R). A portion of the resulting mixture was removed, and the phase inversion temperature of the mixture was measured in the same manner as in Production Example 1. As a result, the phase inversion temperature was 73 to 82 °C.

[0211] After measuring the phase inversion temperature of the mixture, the reaction vessel was heated in a water bath under stirring while nitrogen gas was introduced into the reaction vessel.

[0212] After the internal temperature of the reaction vessel reached 85°C, the reaction vessel was removed from the water bath and air-cooled with stirring until the internal temperature reached 40°C or lower, thereby obtaining an aqueous dispersion containing monomer emulsion particles.

[0213] The dispersion stability of the obtained aqueous dispersion containing monomer emulsion particles and the average particle size of the monomer emulsion particles were examined in the same manner as in Production Example 1. The results are shown in Table 1.

[0214] Next, 100 parts of the monomer emulsion particle-containing aqueous dispersion obtained above was placed in a reaction vessel, and 2.6 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, product name: ADEKA REASOAP SR-20) was added to the reaction vessel. The mixture was stirred at room temperature for 30 minutes while introducing nitrogen gas into the reactor, and then the reaction vessel was placed in a water bath and heated in the water bath with stirring until the internal temperature of the reaction vessel reached 72°C.

[0215] Then, 0.9 parts of a 5% aqueous potassium persulfate solution was added to the reaction vessel, and the contents of the reaction vessel were reacted at an internal temperature of 72°C for 1 hour, and then heated with stirring at an internal temperature of 80°C for 5 hours, thereby polymerizing the monomers contained in the monomer emulsion particles and obtaining an aqueous dispersion containing polymer emulsion particles.

[0216] The average particle size of the polymer emulsion particles contained in the aqueous dispersion containing the polymer emulsion particles obtained above was measured in the same manner as above, and the result was that the average particle size of the polymer emulsion particles was 53 nm.

[0217] Manufacturing Example 6 Into a reaction vessel equipped with a stirrer, a temperature sensor, a condenser, a nitrogen inlet tube, and a dropping funnel were added 66 parts of deionized water, 9.9 parts of a polyoxyalkylene alkenyl ether as a nonionic emulsifier (manufactured by Kao Corporation, trade name: Latemul PD-420, HLB: 12.6), 2.0 parts of MMA, 10.2 parts of CHMA, 3.8 parts of St, 0.3 parts of 1,6HXA, 5.0 parts of C22A, 1.5 parts of an ultraviolet absorber (manufactured by BASF, trade name: Tinuvin (registered trademark) 479), 0.4 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adekastab LA-87), 0.5 parts of an oil-soluble blue dye (manufactured by Kiwa Chemical Industry Co., Ltd., trade name: KPPlast Blue R), and 0.5 parts of an oil-soluble chromium complex salt black dye (manufactured by Orient Chemical Industries Co., Ltd., trade name: VALIFAST). A portion of the resulting mixture was taken out and the phase inversion temperature of the mixture was measured in the same manner as in Production Example 1. As a result, the phase inversion temperature was 77 to 88°C.

[0218] After measuring the phase inversion temperature of the mixture, the reaction vessel was heated in a water bath under stirring while nitrogen gas was introduced into the reaction vessel.

[0219] After the internal temperature of the reaction vessel reached 90°C, the reaction vessel was removed from the water bath and air-cooled with stirring until the internal temperature reached 40°C or lower, thereby obtaining an aqueous dispersion containing monomer emulsion particles.

[0220] The dispersion stability of the obtained aqueous dispersion containing monomer emulsion particles and the average particle size of the monomer emulsion particles were examined in the same manner as in Production Example 1. The results are shown in Table 1.

[0221] Next, 100 parts of the monomer emulsion particle-containing aqueous dispersion obtained above was placed in a reaction vessel, and 2.9 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, product name: ADEKA REASOAP SR-20) was added to the reaction vessel. The mixture was stirred at room temperature for 30 minutes while introducing nitrogen gas into the reactor, and then the reaction vessel was placed in a water bath and heated in the water bath with stirring until the internal temperature of the reaction vessel reached 72°C.

[0222] Then, 1.0 parts of a 5% aqueous potassium persulfate solution was added to the reaction vessel, and the contents of the reaction vessel were reacted at an internal temperature of 72°C for 1 hour, and then heated with stirring at an internal temperature of 80°C for 5 hours, thereby polymerizing the monomers contained in the monomer emulsion particles and obtaining an aqueous dispersion containing polymer emulsion particles.

[0223] The average particle size of the polymer emulsion particles contained in the aqueous dispersion containing the polymer emulsion particles obtained above was measured in the same manner as above, and the result was that the average particle size of the polymer emulsion particles was 64 nm.

[0224] Manufacturing Example 7 Into a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, a nitrogen inlet tube, and a dropping funnel, 36.6 parts of deionized water, 40.6 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, trade name: ADEKA REASOAP SR-20), 2.9 parts of MMA, 8.1 parts of CHMA, 1.0 part of St, 0.3 parts of 1,6HXA, 4.4 parts of EHC, 2.5 parts of an ultraviolet absorber (manufactured by BASF, trade name: Tinuvin (registered trademark) 400), 0.5 parts of an ultraviolet absorber (manufactured by BASF, trade name: Tinuvin (registered trademark) 479), and an oil-soluble ultraviolet absorber (SHUANG BANG 2.0 parts of a stabilizer (manufactured by INDUSTRIAL CORP., trade name: SB-UVA650), 1.0 part of a hindered amine light stabilizer (manufactured by ADEKA CORPORATION, trade name: ADK STAB LA-87), and 1.3 parts of an oil-soluble chromium complex salt red dye were charged, and a portion of the resulting mixture was taken out, and the phase inversion temperature of the mixture was measured in the same manner as in Example 1. As a result, no phase inversion temperature was confirmed.

[0225] After measuring the phase inversion temperature of the mixture, the reaction vessel was heated in a water bath under stirring while nitrogen gas was introduced into the reaction vessel.

[0226] After the internal temperature of the reaction vessel reached 92°C, the reaction vessel was removed from the water bath and air-cooled under stirring until the internal temperature reached 40°C or below, thereby obtaining an aqueous dispersion containing monomer emulsion particles, but the colorant immediately precipitated.

[0227] Manufacturing Example 8 A reaction vessel equipped with a stirrer, a temperature sensor, a condenser, a nitrogen inlet tube, and a dropping funnel was charged with 67.0 parts of deionized water, 10.8 parts of a polyoxyalkylene alkenyl ether as a nonionic emulsifier (manufactured by Kao Corporation, trade name: Latemul PD-420, HLB: 12.6), 2.9 parts of MMA, 6.2 parts of CHMA, 0.3 parts of 1,6HXA, 9.3 parts of LMA, and 1.0 part of an ultraviolet absorber (manufactured by BASF, trade name: Tinuvin (registered trademark) 400). 0.5 parts of an ultraviolet absorber (manufactured by BASF, trade name: Tinuvin® 479), 0.4 parts of an oil-soluble ultraviolet absorber (manufactured by ADEKA Corporation, trade name: Adeka STAB LA-F70), 0.6 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adeka STAB LA-87), and 1.0 parts of an oil-soluble chromium complex salt red dye were charged, and a portion of the resulting mixture was removed, and the phase inversion temperature of the mixture was measured in the same manner as in Example 1. As a result, no phase inversion temperature was confirmed.

[0228] After measuring the phase inversion temperature of the mixture, the reaction vessel was heated in a water bath under stirring while nitrogen gas was introduced into the reaction vessel.

[0229] After the internal temperature of the reaction vessel reached 92°C, the reaction vessel was removed from the water bath and air-cooled under stirring until the internal temperature reached 40°C or below, thereby obtaining an aqueous dispersion containing monomer emulsion particles. However, the colorant precipitated within a few days after the preparation.

[0230] The dispersion stability of the obtained aqueous dispersion containing monomer emulsion particles and the average particle size of the monomer emulsion particles were examined in the same manner as in Example 1. The results are shown in Table 1.

[0231] Next, 100 parts of the monomer-containing aqueous mixture obtained above was placed in a reaction vessel, and 2.6 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, trade name: ADEKA REASOAP SR-20) was added to the reaction vessel. The mixture was stirred at room temperature for 30 minutes while introducing nitrogen gas into the reactor, and then the reaction vessel was placed in a water bath and heated in the water bath with stirring until the internal temperature of the reaction vessel reached 75°C.

[0232] Then, 0.9 parts of a 5% aqueous potassium persulfate solution was added to the reaction vessel, and the contents of the reaction vessel were heated with stirring at an internal temperature of 75°C for 1 hour, followed by an internal temperature of 80°C for 5 hours, thereby polymerizing the monomers contained in the monomer emulsion particles and obtaining an aqueous dispersion containing polymer emulsion particles.

[0233] The average particle size of the polymer emulsion particles contained in the aqueous dispersion containing the polymer emulsion particles obtained above was measured in the same manner as above, and the result was that the average particle size of the polymer emulsion particles was 170 nm.

[0234] Manufacturing Example 9 A reaction vessel equipped with a stirrer, a temperature sensor, a condenser, a nitrogen inlet tube, and a dropping funnel was charged with 66.6 parts of deionized water, 10.8 parts of a polyoxyalkylene alkenyl ether (manufactured by Kao Corporation, trade name: Latemul PD-420, HLB: 12.6) as a nonionic emulsifier, 3.0 parts of MMA, 7.8 parts of CHMA, 1.7 parts of St, 0.9 parts of VP, 0.2 parts of 1,6HXA, 1.5 parts of EHC, 1.8 parts of CS-16, 1.8 parts of an ultraviolet absorber (manufactured by BASF, trade name: Tinuvin (registered trademark) 40 2.0 parts of ethanol (product of ADEKA Corporation, trade name: ADK STAB LA-F70), 1.3 parts of an oil-soluble UV absorber (product of ADEKA Corporation, trade name: ADK STAB LA-87), 0.2 parts of a hindered amine light stabilizer (product of BASF, trade name: Tinuvin® 292), 1.5 parts of an oil-soluble chromium complex salt red dye, 0.1 parts of a methine yellow dye, 0.1 parts of an oil-soluble chromium complex salt black dye (product of Orient Chemical Industries, Ltd., trade name: VALIFAST BLACK 3810), and 0.1 parts of an anthraquinone purple dye were charged into a flask. A portion of the resulting mixture was removed, and the phase inversion temperature of the mixture was measured in the same manner as in Production Example 1. The resulting phase inversion temperature was 72 to 79°C.

[0235] After measuring the phase inversion temperature of the mixture, the reaction vessel was heated in a water bath under stirring while nitrogen gas was introduced into the reaction vessel.

[0236] After the internal temperature of the reaction vessel reached 85°C, the reaction vessel was removed from the water bath and air-cooled with stirring until the internal temperature reached 40°C or lower, thereby obtaining an aqueous dispersion containing monomer emulsion particles.

[0237] The dispersion stability of the obtained aqueous dispersion containing monomer emulsion particles and the average particle size of the monomer emulsion particles were examined in the same manner as in Production Example 1. The results are shown in Table 1.

[0238] Next, 100 parts of the monomer emulsion particle-containing aqueous dispersion obtained above was placed in a reaction vessel, and 2.9 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, product name: ADEKA REASOAP SR-20) was added to the reaction vessel. The mixture was stirred at room temperature for 30 minutes while introducing nitrogen gas into the reactor, and then the reaction vessel was placed in a water bath and heated in the water bath with stirring until the internal temperature of the reaction vessel reached 58°C.

[0239] Then, 0.5 parts of a 20% aqueous solution of 2,2-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride was added to the reaction vessel, and the contents of the reaction vessel were reacted at an internal temperature of 58°C for 1 hour, and then heated with stirring at an internal temperature of 63°C for 5 hours, thereby polymerizing the monomers contained in the monomer emulsion particles and obtaining an aqueous dispersion containing polymer emulsion particles.

[0240] The average particle size of the polymer emulsion particles contained in the aqueous dispersion containing the polymer emulsion particles obtained above was measured in the same manner as above, and the result was that the average particle size of the polymer emulsion particles was 44 nm.

[0241] Manufacturing Example 10 Into a reaction vessel equipped with a stirrer, a temperature sensor, a condenser, a nitrogen inlet tube, and a dropping funnel, were added 65.0 parts of deionized water, 11.2 parts of a polyoxyalkylene alkenyl ether as a nonionic emulsifier (manufactured by Kao Corporation, trade name: Latemul PD-420, HLB: 12.6), 3.2 parts of MMA, 6.9 parts of CHMA, 1.9 parts of St, 1.0 part of VP, 0.2 parts of CTA, 3.5 parts of EHC, 1.2 parts of CS-16, 1.0 part of an ultraviolet absorber (manufactured by BASF, trade name: Tinuvin (registered trademark) 400), and 1.0 part of an ultraviolet absorber (manufactured by BASF, trade name: Tinuvin (registered trademark) 400). A mixture containing 1.1 parts of an oil-soluble ultraviolet absorber (manufactured by ADEKA Corporation, trade name: ADK STAB LA-F70), 1.4 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: ADK STAB LA-87), 0.2 parts of a hindered amine light stabilizer (manufactured by BASF, trade name: Tinuvin® 292), 1.6 parts of an oil-soluble chromium complex salt red dye, 0.1 parts of a methine yellow dye, and 0.1 parts of an anthraquinone violet dye was charged. A portion of the resulting mixture was removed, and the phase inversion temperature of the mixture was measured in the same manner as in Production Example 1. The resulting phase inversion temperature was 75 to 81°C.

[0242] After measuring the phase inversion temperature of the mixture, the reaction vessel was heated in a water bath under stirring while nitrogen gas was introduced into the reaction vessel.

[0243] After the internal temperature of the reaction vessel reached 86°C, the reaction vessel was removed from the water bath and air-cooled with stirring until the internal temperature reached 40°C or lower, thereby obtaining an aqueous dispersion containing monomer emulsion particles.

[0244] The dispersion stability of the obtained aqueous dispersion containing monomer emulsion particles and the average particle size of the monomer emulsion particles were examined in the same manner as in Production Example 1. The results are shown in Table 1.

[0245] Next, 100 parts of the monomer emulsion particle-containing aqueous dispersion obtained above was placed in a reaction vessel, and the mixture was stirred at room temperature for 30 minutes while introducing nitrogen gas into the reactor.The reaction vessel was then placed in a water bath, and the internal temperature of the reaction vessel was raised in the water bath while stirring until it reached 58°C.

[0246] Then, 0.5 parts of a 20% aqueous solution of 2,2-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride was added to the reaction vessel, and the contents of the reaction vessel were reacted at an internal temperature of 58°C for 1 hour, and then heated with stirring at an internal temperature of 63°C for 5 hours, thereby polymerizing the monomers contained in the monomer emulsion particles and obtaining an aqueous dispersion containing polymer emulsion particles.

[0247] The average particle size of the polymer emulsion particles contained in the aqueous dispersion containing the polymer emulsion particles obtained above was measured in the same manner as above, and the result was that the average particle size of the polymer emulsion particles was 48 nm.

[0248] Manufacturing Example 11 Into a reaction vessel equipped with a stirrer, a temperature sensor, a condenser, a nitrogen inlet tube, and a dropping funnel, 60.0 parts of deionized water, 12.8 parts of a polyoxyalkylene alkenyl ether as a nonionic emulsifier (manufactured by Kao Corporation, trade name: Latemul PD-420, HLB: 12.6), 3.6 parts of MMA, 8.0 parts of CHMA, 2.0 parts of St, 1.1 parts of VP, 0.2 parts of CTA, 4.0 parts of EHC, 1.2 parts of CS-16, 0.8 parts of an ultraviolet absorber (manufactured by BASF, trade name: Tinuvin (registered trademark) 400), and 1.0 parts of an oil-soluble ultraviolet absorber (manufactured by ADEKA Corporation, trade name: A) were added. A mixture containing 1.6 parts of DecaStab LA-F70, 1.6 parts of an ultraviolet absorbing monomer (manufactured by Otsuka Chemical Co., Ltd., trade name: RUVA-93), 0.2 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adekastab LA-87), 0.5 parts of a hindered amine light stabilizer (manufactured by BASF, trade name: Tinuvin® 292), 1.8 parts of an oil-soluble chromium complex salt red dye, 0.2 parts of a methine yellow dye, and 0.1 parts of an anthraquinone purple dye was charged, and a portion of the resulting mixture was removed and the phase inversion temperature of the mixture was measured in the same manner as in Production Example 1. The resulting phase inversion temperature was 81 to 85°C.

[0249] After measuring the phase inversion temperature of the mixture, the reaction vessel was heated in a water bath under stirring while nitrogen gas was introduced into the reaction vessel.

[0250] After the internal temperature of the reaction vessel reached 90°C, the reaction vessel was removed from the water bath and air-cooled with stirring until the internal temperature reached 40°C or lower, thereby obtaining an aqueous dispersion containing monomer emulsion particles.

[0251] The dispersion stability of the obtained aqueous dispersion containing monomer emulsion particles and the average particle size of the monomer emulsion particles were examined in the same manner as in Production Example 1. The results are shown in Table 1.

[0252] Next, 100 parts of the monomer emulsion particle-containing aqueous dispersion obtained above was placed in a reaction vessel, and the mixture was stirred at room temperature for 30 minutes while introducing nitrogen gas into the reactor.The reaction vessel was then placed in a water bath, and the internal temperature of the reaction vessel was raised in the water bath while stirring until it reached 58°C.

[0253] Then, 0.6 parts of a 20% aqueous solution of 2,2-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride was added to the reaction vessel, and the contents of the reaction vessel were reacted at an internal temperature of 58°C for 1 hour, and then heated with stirring at an internal temperature of 63°C for 5 hours, thereby polymerizing the monomers contained in the monomer emulsion particles and obtaining an aqueous dispersion containing polymer emulsion particles.

[0254] The average particle size of the polymer emulsion particles contained in the aqueous dispersion containing the polymer emulsion particles obtained above was measured in the same manner as above, and the result was that the average particle size of the polymer emulsion particles was 44 nm.

[0255] [Table 1]

[0256] Example 1 A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, a nitrogen inlet tube, and a dropping funnel was charged with 27.9 parts of the aqueous dispersion containing polymer emulsion particles obtained in Production Example 1 and 40.4 parts of deionized water, and the reaction vessel was heated with stirring using a water bath until the internal temperature reached 80°C.

[0257] While maintaining the internal temperature at 80°C, 2.6 parts of a 3.5% aqueous solution of ammonium persulfate was added to the reaction vessel and stirred for 10 minutes. Then, while maintaining the internal temperature at 80°C, a mixture of 9.1 parts of deionized water, 2.5 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, trade name: Adeka Reasoap SR-20), 6.0 parts of MMA, 6.1 parts of EHA, 3.7 parts of CHMA, 0.4 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adekastab LA-87), 0.3 parts of HEMA, 0.6 parts of an ultraviolet-absorbing monomer (manufactured by Otsuka Chemical Co., Ltd., trade name: RUVA-93), 0.1 parts of methacryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product number: KMB-503), and 0.1 parts of an oil-soluble chromium complex red dye was added dropwise to the reaction vessel over 90 minutes with stirring.

[0258] Sixty minutes after the end of the dropwise addition, 0.1 parts of 25% aqueous ammonia solution was added to the reaction vessel to neutralize the contents. Thirty minutes after the end of neutralization, the reaction vessel was removed from the water bath, and the internal temperature of the reaction vessel was cooled to 40°C or below. Then, 0.1 parts of a preservative (manufactured by DuPont, trade name: KORDEK MLX) was added to the reaction vessel to obtain an aqueous dispersion containing polymer emulsion particles having a resin layer formed by polymerizing the resin layer-forming monomer component on the surface of the polymer emulsion particles obtained in Production Example 1. The nonvolatile content of the aqueous dispersion containing polymer emulsion particles having a resin layer obtained above was 26.0% by mass.

[0259] The average particle size of the polymer emulsion particles contained in the obtained aqueous dispersion containing polymer emulsion particles having a resin layer was measured immediately after production in the same manner as above, and was found to be 70 nm.

[0260] Example 2 A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, a nitrogen inlet tube, and a dropping funnel was charged with 27.9 parts of the aqueous dispersion containing polymer emulsion particles obtained in Production Example 1 and 40.4 parts of deionized water, and the reaction vessel was heated with stirring using a water bath until the internal temperature reached 80°C.

[0261] While maintaining the internal temperature at 80°C, 2.6 parts of a 3.5% aqueous solution of ammonium persulfate was added to the reaction vessel, followed by stirring for 10 minutes. Then, while maintaining the internal temperature at 80°C, 9.1 parts of deionized water, 2.5 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, trade name: Adeka Reasoap SR-20), 5.8 parts of MMA, 5.9 parts of EHA, 3.7 parts of CHMA, 0.4 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adekastab LA-87), 0.3 parts of HEMA, and an ultraviolet absorbing monomer (manufactured by Otsuka Chemical Co., Ltd., trade name: RUVA- A mixture of 0.6 parts of methacryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product number: KMB-503), 0.1 parts of an ultraviolet absorber (manufactured by BASF, product name: Tinuvin (registered trademark) 479), 0.2 parts of an ultraviolet absorber (manufactured by BASF, product name: Tinuvin (registered trademark) 970), and 0.1 parts of an oil-soluble chromium complex salt black dye was added dropwise to a reaction vessel over 90 minutes with stirring.

[0262] Sixty minutes after the end of the dropwise addition, 0.1 parts of 25% aqueous ammonia solution was added to the reaction vessel to neutralize the contents. Thirty minutes after the end of neutralization, the reaction vessel was removed from the water bath, and the internal temperature of the reaction vessel was cooled to 40°C or below. Then, 0.1 parts of a preservative (manufactured by DuPont, trade name: KORDEK MLX) was added to the reaction vessel to obtain an aqueous dispersion containing polymer emulsion particles having a resin layer formed by polymerizing the resin layer-forming monomer component on the surface of the polymer emulsion particles obtained in Production Example 1. The nonvolatile content of the aqueous dispersion containing polymer emulsion particles having a resin layer obtained above was 26.0% by mass.

[0263] The average particle size of the polymer emulsion particles contained in the obtained aqueous dispersion containing polymer emulsion particles having a resin layer was measured immediately after production in the same manner as above, and was found to be 75 nm.

[0264] Example 3 A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, a nitrogen inlet tube, and a dropping funnel was charged with 27.9 parts of the aqueous dispersion containing polymer emulsion particles obtained in Production Example 2 and 40.4 parts of deionized water, and the reaction vessel was heated with stirring using a water bath until the internal temperature reached 80°C.

[0265] While maintaining the internal temperature at 80°C, 2.6 parts of a 3.5% aqueous solution of ammonium persulfate was added to the reaction vessel and stirred for 10 minutes. Then, while maintaining the internal temperature at 80°C, a mixture of 9.1 parts of deionized water, 2.5 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, trade name: Adeka Reasoap SR-20), 6.0 parts of MMA, 6.1 parts of EHA, 3.7 parts of CHMA, 0.4 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adekastab LA-87), 0.3 parts of HEMA, 0.6 parts of an ultraviolet absorbing monomer (manufactured by Otsuka Chemical Co., Ltd., trade name: RUVA-93), 0.1 parts of methacryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product number: KMB-503), and 0.1 parts of an oil-soluble chromium complex salt black dye was added dropwise to the reaction vessel over 90 minutes with stirring.

[0266] Sixty minutes after the end of the dropwise addition, 0.1 parts of 25% aqueous ammonia solution was added to the reaction vessel to neutralize the contents. Thirty minutes after the end of neutralization, the reaction vessel was removed from the water bath, and the internal temperature of the reaction vessel was cooled to 40°C or below. Then, 0.1 parts of a preservative (DuPont, trade name: KORDEK MLX) was added to the reaction vessel to obtain an aqueous dispersion containing polymer emulsion particles having a resin layer formed by polymerizing the resin layer-forming monomer component on the surface of the polymer emulsion particles obtained in Production Example 2. The nonvolatile content of the aqueous dispersion containing polymer emulsion particles having a resin layer obtained above was 26.0% by mass.

[0267] The average particle size of the polymer emulsion particles contained in the obtained aqueous dispersion containing polymer emulsion particles having a resin layer was measured immediately after production in the same manner as above, and was found to be 63 nm.

[0268] Example 4 A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, a nitrogen inlet tube, and a dropping funnel was charged with 41.1 parts of the aqueous dispersion containing polymer emulsion particles obtained in Production Example 3 and 35.1 parts of deionized water, and the reaction vessel was heated with stirring using a water bath until the internal temperature reached 80°C.

[0269] While maintaining the internal temperature at 80°C, 1.4 parts of a 3.5% aqueous solution of ammonium persulfate was added to the reaction vessel, followed by stirring for 10 minutes. Thereafter, while maintaining the internal temperature at 80°C, 7.1 parts of deionized water, 1.6 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, trade name: Adeka Reasoap SR-20), 4.5 parts of MMA, 4.7 parts of EHA, 2.8 parts of CHMA, 0.6 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adekastab LA-87), 0.2 parts of HEMA, 0.4 parts of an ultraviolet absorbing monomer (manufactured by Otsuka Chemical Co., Ltd., trade name: RUVA-93), and methacryloyloxypropyltrimethoxysilane were added. A mixture of 0.1 part of orchid (manufactured by Shin-Etsu Chemical Co., Ltd., product number: KMB-503), 0.2 parts of an ultraviolet absorber (manufactured by BASF, product name: Tinuvin® 479), 0.1 parts of an ultraviolet absorber (manufactured by BASF, product name: Tinuvin® 970), 0.1 parts of an oil-soluble ultraviolet absorber (manufactured by ADEKA Corporation, product name: Adekastab LA-F70), 0.1 parts of an oil-soluble chromium complex salt red dye, and 0.1 parts of an oil-soluble chromium complex salt black dye was added dropwise to a reaction vessel over 90 minutes with stirring.

[0270] Sixty minutes after the end of the dropwise addition, 0.1 parts of 25% aqueous ammonia solution was added to the reaction vessel to neutralize the contents. Thirty minutes after the end of neutralization, the reaction vessel was removed from the water bath, and the internal temperature of the reaction vessel was cooled to 40°C or below. Then, 0.1 parts of a preservative (manufactured by DuPont, trade name: KORDEK MLX) was added to the reaction vessel to obtain an aqueous dispersion containing polymer emulsion particles having a resin layer formed by polymerizing the monomer component for forming the resin layer on the surface of the polymer emulsion particles obtained in Production Example 3. The nonvolatile content of the aqueous dispersion containing polymer emulsion particles having a resin layer obtained above was 26.0% by mass.

[0271] The average particle size of the polymer emulsion particles contained in the obtained aqueous dispersion containing polymer emulsion particles having a resin layer was measured immediately after production in the same manner as above, and was found to be 55 nm.

[0272] Example 5 A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, a nitrogen inlet tube, and a dropping funnel was charged with 27.9 parts of the aqueous dispersion containing polymer emulsion particles obtained in Production Example 4 and 40.4 parts of deionized water, and the reaction vessel was heated with stirring using a water bath until the internal temperature reached 80°C.

[0273] While maintaining the internal temperature at 80°C, 2.6 parts of a 3.5% aqueous solution of ammonium persulfate was added to the reaction vessel, followed by stirring for 10 minutes. Then, while maintaining the internal temperature at 80°C, 9.1 parts of deionized water, 2.5 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, trade name: Adeka Reasoap SR-20), 5.8 parts of MMA, 5.9 parts of EHA, 3.7 parts of CHMA, 0.4 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adekastab LA-87), 0.3 parts of HEMA, and an ultraviolet absorbing monomer (manufactured by Otsuka Chemical Co., Ltd., trade name: RUVA- A mixture of 0.6 parts of methacryloyloxypropyltrimethoxysilane [manufactured by Shin-Etsu Chemical Co., Ltd., product number: KMB-503], 0.2 parts of an ultraviolet absorber [manufactured by BASF, product name: Tinuvin (registered trademark) 479], 0.1 parts of an ultraviolet absorber [manufactured by BASF, product name: Tinuvin (registered trademark) 970], and 0.1 parts of an oil-soluble chromium complex salt black dye was added dropwise to a reaction vessel over 90 minutes with stirring.

[0274] Sixty minutes after the end of the dropwise addition, 0.1 parts of 25% aqueous ammonia solution was added to the reaction vessel to neutralize the contents. Thirty minutes after the end of neutralization, the reaction vessel was removed from the water bath, and the internal temperature of the reaction vessel was cooled to 40°C or below. Then, 0.1 parts of a preservative (manufactured by DuPont, product name: KORDEK MLX) was added to the reaction vessel to obtain an aqueous dispersion containing polymer emulsion particles having a resin layer formed by polymerizing the monomer component for forming the resin layer on the surface of the polymer emulsion particles obtained in Production Example 4. The nonvolatile content of the aqueous dispersion containing polymer emulsion particles having a resin layer obtained above was 26.0% by mass.

[0275] The average particle size of the polymer emulsion particles contained in the obtained aqueous dispersion containing polymer emulsion particles having a resin layer was measured immediately after production in the same manner as above, and was found to be 71 nm.

[0276] Example 6 A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, a nitrogen inlet tube, and a dropping funnel was charged with 30.6 parts of the aqueous dispersion containing polymer emulsion particles obtained in Production Example 5 and 31.4 parts of deionized water, and the reaction vessel was heated with stirring using a water bath until the internal temperature reached 80°C.

[0277] While maintaining the internal temperature at 80°C, 1.7 parts of a 3.5% aqueous solution of ammonium persulfate was added to the reaction vessel, followed by stirring for 10 minutes. Thereafter, while maintaining the internal temperature at 80°C, 13.9 parts of deionized water, 2.9 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, trade name: Adeka Reasoap SR-20), 6.7 parts of MMA, 6.9 parts of EHA, 4.1 parts of CHMA, 0.4 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adekastab LA-87), 0.3 parts of HEMA, and an ultraviolet absorbing monomer (manufactured by Otsuka Chemical Co., Ltd., trade name: RUVA-9) were added. A mixture of 0.6 parts of methyl methacrylate 3), 0.1 parts of methacryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product number KMB-503), 0.2 parts of an ultraviolet absorber (manufactured by BASF, product name: Tinuvin (registered trademark) 479), 0.2 parts of an ultraviolet absorber (manufactured by BASF, product name: Tinuvin (registered trademark) 970), and 0.1 parts of an oil-soluble chromium complex salt black dye was added dropwise to a reaction vessel over 90 minutes with stirring.

[0278] Sixty minutes after the end of the dropwise addition, 0.1 parts of 25% aqueous ammonia solution was added to the reaction vessel to neutralize the contents. Thirty minutes after the end of neutralization, the reaction vessel was removed from the water bath, and the internal temperature of the reaction vessel was cooled to 40°C or below. Then, 0.1 parts of a preservative (manufactured by DuPont, trade name: KORDEK MLX) was added to the reaction vessel to obtain an aqueous dispersion containing polymer emulsion particles having a resin layer formed by polymerizing the resin layer-forming monomer component on the surface of the polymer emulsion particles obtained in Production Example 5. The nonvolatile content of the aqueous dispersion containing polymer emulsion particles having a resin layer obtained above was 30.0% by mass.

[0279] The average particle size of the polymer emulsion particles contained in the obtained aqueous dispersion containing polymer emulsion particles having a resin layer was measured immediately after production in the same manner as above, and was found to be 67 nm.

[0280] Example 7 A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, a nitrogen inlet tube, and a dropping funnel was charged with 30.6 parts of the aqueous dispersion containing polymer emulsion particles obtained in Production Example 6 and 31.4 parts of deionized water, and the reaction vessel was heated with stirring using a water bath until the internal temperature reached 80°C.

[0281] While maintaining the internal temperature at 80°C, 1.7 parts of a 3.5% aqueous solution of ammonium persulfate was added to the reaction vessel, followed by stirring for 10 minutes. Thereafter, while maintaining the internal temperature at 80°C, 13.9 parts of deionized water, 2.9 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, trade name: Adeka Reasoap SR-20), 6.7 parts of MMA, 6.9 parts of EHA, 4.1 parts of CHMA, 0.4 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adeka Stab LA-87), 0.3 parts of HEMA, and an ultraviolet absorbing monomer (manufactured by Otsuka Chemical Co., Ltd., trade name: RUV A mixture of 0.6 parts of methacryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product number: KMB-503), 0.2 parts of an ultraviolet absorber (manufactured by BASF, product name: Tinuvin (registered trademark) 479), 0.2 parts of an ultraviolet absorber (manufactured by BASF, product name: Tinuvin (registered trademark) 970), and 0.1 parts of an oil-soluble blue dye was added dropwise to a reaction vessel over 90 minutes with stirring.

[0282] Sixty minutes after the end of the dropwise addition, 0.1 parts of 25% aqueous ammonia solution was added to the reaction vessel to neutralize the contents. Thirty minutes after the end of neutralization, the reaction vessel was removed from the water bath, and the internal temperature of the reaction vessel was cooled to 40°C or below. Then, 0.1 parts of a preservative (manufactured by DuPont, trade name: KORDEK MLX) was added to the reaction vessel to obtain an aqueous dispersion containing polymer emulsion particles having a resin layer formed by polymerizing the monomer component for forming the resin layer on the surface of the polymer emulsion particles obtained in Production Example 6. The nonvolatile content of the aqueous dispersion containing polymer emulsion particles having a resin layer obtained above was 30.0% by mass.

[0283] The average particle size of the polymer emulsion particles contained in the obtained aqueous dispersion containing polymer emulsion particles having a resin layer was measured immediately after production in the same manner as above, and was found to be 78 nm.

[0284] Example 8 A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, a nitrogen inlet tube, and a dropping funnel was charged with 27.9 parts of the aqueous dispersion containing polymer emulsion particles obtained in Production Example 3 and 44.4 parts of deionized water, and the reaction vessel was heated with stirring using a water bath until the internal temperature reached 80°C.

[0285] While maintaining the internal temperature at 80°C, 1.4 parts of a 3.5% aqueous solution of ammonium persulfate was added to the reaction vessel, followed by stirring for 10 minutes. Thereafter, while maintaining the internal temperature at 80°C, 7.1 parts of deionized water, 2.4 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, trade name: Adeka Reasoap SR-20), 5.8 parts of MMA, 4.9 parts of EHA, 2.0 parts of CHMA, 2.0 parts of St, 0.4 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adeka Stab LA-87), 0.3 parts of HEMA, and an ultraviolet absorbing monomer (Otsuka A mixture of 0.6 parts of methacryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product number: KMB-503), 0.1 parts of an oil-soluble ultraviolet absorber (manufactured by ADEKA Corporation, product number: Adeka STAB LA-F70), 0.3 parts of a methine yellow dye, and 0.2 parts of an anthraquinone purple dye was added dropwise to a reaction vessel over 90 minutes with stirring.

[0286] Sixty minutes after the end of the dropwise addition, 0.1 parts of 25% aqueous ammonia solution was added to the reaction vessel to neutralize the contents. Thirty minutes after the end of neutralization, the reaction vessel was removed from the water bath, and the internal temperature of the reaction vessel was cooled to 40°C or below. Then, 0.1 parts of a preservative (manufactured by DuPont, trade name: KORDEK MLX) was added to the reaction vessel to obtain an aqueous dispersion containing polymer emulsion particles having a resin layer formed by polymerizing the monomer component for forming the resin layer on the surface of the polymer emulsion particles obtained in Production Example 3. The nonvolatile content of the aqueous dispersion containing polymer emulsion particles having a resin layer obtained above was 26.0% by mass.

[0287] The average particle size of the polymer emulsion particles contained in the obtained aqueous dispersion containing polymer emulsion particles having a resin layer was measured immediately after production in the same manner as above, and was found to be 59 nm.

[0288] Example 9 A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, a nitrogen inlet tube, and a dropping funnel was charged with 41.1 parts of the aqueous dispersion containing polymer emulsion particles obtained in Production Example 4 and 43.0 parts of deionized water, and the reaction vessel was heated with stirring using a water bath until the internal temperature reached 80°C.

[0289] While maintaining the internal temperature at 80°C, 1.4 parts of a 3.5% aqueous solution of ammonium persulfate was added to the reaction vessel, and the mixture was stirred for 10 minutes. Thereafter, while maintaining the internal temperature at 80°C, a mixture of 7.1 parts of deionized water, 1.6 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, trade name: ADEKA REASOAP SR-20), 4.5 parts of MMA, 3.0 parts of EHA, 1.0 part of CHMA, 3.0 parts of St, 0.6 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adeka STAB LA-87), 0.2 parts of HEMA, 0.4 parts of an ultraviolet absorbing monomer (manufactured by Otsuka Chemical Co., Ltd., trade name: RUVA-93), 0.1 parts of methacryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product number: KMB-503), 0.1 parts of an oil-soluble ultraviolet absorber (manufactured by ADEKA Corporation, trade name: Adeka STAB LA-F70), and 0.1 parts of a perylene-based red fluorescent dye was added dropwise to the reaction vessel over 90 minutes with stirring.

[0290] Sixty minutes after the end of the dropwise addition, 0.1 parts of 25% aqueous ammonia solution was added to the reaction vessel to neutralize the contents. Thirty minutes after the end of neutralization, the reaction vessel was removed from the water bath, and the internal temperature of the reaction vessel was cooled to 40°C or below. Then, 0.1 parts of a preservative (manufactured by DuPont, product name: KORDEK MLX) was added to the reaction vessel to obtain an aqueous dispersion containing polymer emulsion particles having a resin layer formed by polymerizing the monomer component for forming the resin layer on the surface of the polymer emulsion particles obtained in Production Example 4. The nonvolatile content of the aqueous dispersion containing polymer emulsion particles having a resin layer obtained above was 26.0% by mass.

[0291] The average particle size of the polymer emulsion particles contained in the obtained aqueous dispersion containing polymer emulsion particles having a resin layer was measured immediately after production in the same manner as above, and was found to be 63 nm.

[0292] Example 10 A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, a nitrogen inlet tube, and a dropping funnel was charged with 30.6 parts of the aqueous dispersion containing polymer emulsion particles obtained in Production Example 9 and 37.3 parts of deionized water, and the reaction vessel was heated with stirring using a water bath until the internal temperature reached 57°C.

[0293] While maintaining the internal temperature at 57°C, 0.5 parts of a 20% aqueous solution of 2,2-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride was added to the reaction vessel, and the mixture was stirred for 20 minutes. Thereafter, while maintaining the internal temperature at 57°C, 7.1 parts of deionized water, 2.8 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, trade name: Adeka Reasoap SR-20), 7.7 parts of MMA, 5.0 parts of EHA, 4.1 parts of CHMA, 3.0 parts of St, 0.4 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adeka Stab LA-87), 0.3 parts of HEMA, and an ultraviolet absorbing monomer (Otsuka A mixture of 0.6 parts of methacryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product number: KMB-503), 0.1 parts of an oil-soluble ultraviolet absorber (manufactured by ADEKA Corporation, product number: Adeka STAB LA-F70), 0.2 parts of a methine yellow dye, and 0.1 parts of an anthraquinone purple dye was added dropwise to a reaction vessel over 90 minutes with stirring.

[0294] 120 minutes after the end of the dropwise addition, the reaction vessel was removed from the water bath, and the internal temperature of the reaction vessel was cooled to 40°C or below. 0.1 parts of a preservative (manufactured by DuPont, trade name: KORDEK MLX) was then added to the reaction vessel to obtain an aqueous dispersion containing polymer emulsion particles having a resin layer formed by polymerizing the monomer component for forming the resin layer on the surface of the polymer emulsion particles obtained in Production Example 9. The nonvolatile content of the aqueous dispersion containing polymer emulsion particles having a resin layer obtained above was 32.0% by mass.

[0295] The average particle size of the polymer emulsion particles contained in the obtained aqueous dispersion containing polymer emulsion particles having a resin layer was measured immediately after production in the same manner as above, and was found to be 67 nm.

[0296] Example 11 A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, a nitrogen inlet tube, and a dropping funnel was charged with 29.1 parts of the aqueous dispersion containing polymer emulsion particles obtained in Production Example 10 and 39.2 parts of deionized water, and the reaction vessel was heated with stirring using a water bath until the internal temperature reached 57°C.

[0297] While maintaining the internal temperature at 57°C, 0.5 parts of a 20% aqueous solution of 2,2-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride was added to the reaction vessel, and the mixture was stirred for 20 minutes. Thereafter, while maintaining the internal temperature at 57°C, 7.1 parts of deionized water, 2.8 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, trade name: Adeka Reasoap SR-20), 7.7 parts of MMA, 5.0 parts of EHA, 4.1 parts of CHMA, 3.0 parts of St, 0.4 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adeka Stab LA-87), 0.3 parts of HEMA, and an ultraviolet absorbing monomer (Otsuka A mixture of 0.6 parts of methacryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product number: KMB-503), 0.1 parts of an oil-soluble ultraviolet absorber (manufactured by ADEKA Corporation, product number: Adeka STAB LA-F70), 0.2 parts of a methine yellow dye, and 0.1 parts of an anthraquinone purple dye was added dropwise to a reaction vessel over 90 minutes with stirring.

[0298] 120 minutes after the end of the dropwise addition, the reaction vessel was removed from the water bath, and the internal temperature of the reaction vessel was cooled to 40°C or below. 0.1 parts of a preservative (manufactured by DuPont, trade name: KORDEK MLX) was then added to the reaction vessel to obtain an aqueous dispersion containing polymer emulsion particles having a resin layer formed by polymerizing the monomer component for forming the resin layer on the surface of the polymer emulsion particles obtained in Production Example 10. The nonvolatile content of the aqueous dispersion containing polymer emulsion particles having a resin layer obtained above was 32.0% by mass.

[0299] The average particle size of the polymer emulsion particles contained in the obtained aqueous dispersion containing polymer emulsion particles having a resin layer was measured immediately after production in the same manner as above, and was found to be 78 nm.

[0300] Example 12 A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, a nitrogen inlet tube, and a dropping funnel was charged with 30.6 parts of the aqueous dispersion containing polymer emulsion particles obtained in Production Example 11 and 33.0 parts of deionized water, and the reaction vessel was heated with stirring using a water bath until the internal temperature reached 57°C.

[0301] While maintaining the internal temperature at 57°C, 0.5 parts of a 20% aqueous solution of 2,2-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride was added to the reaction vessel, and the mixture was stirred for 20 minutes. Thereafter, while maintaining the internal temperature at 57°C, 7.1 parts of deionized water, 2.8 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, trade name: Adeka Reasoap SR-20), 8.0 parts of MMA, 7.0 parts of EHA, 4.1 parts of CHMA, 5.0 parts of St, 0.4 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adeka Stab LA-87), 0.3 parts of HEMA, and an ultraviolet absorbing monomer (Otsuka A mixture of 0.6 parts of methacryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product number: KMB-503), 0.1 parts of an oil-soluble ultraviolet absorber (manufactured by ADEKA Corporation, product number: Adeka STAB LA-F70), 0.2 parts of a methine yellow dye, and 0.1 parts of an anthraquinone purple dye was added dropwise to a reaction vessel over 90 minutes with stirring.

[0302] 120 minutes after the end of the dropwise addition, the reaction vessel was removed from the water bath, and the internal temperature of the reaction vessel was cooled to 40°C or below. 0.1 parts of a preservative (manufactured by DuPont, trade name: KORDEK MLX) was then added to the reaction vessel to obtain an aqueous dispersion containing polymer emulsion particles having a resin layer formed by polymerizing the monomer component for forming the resin layer on the surface of the polymer emulsion particles obtained in Production Example 11. The nonvolatile content of the aqueous dispersion containing polymer emulsion particles having a resin layer obtained above was 38.0% by mass.

[0303] The average particle size of the polymer emulsion particles contained in the obtained aqueous dispersion containing polymer emulsion particles having a resin layer was measured immediately after production in the same manner as above, and was found to be 65 nm.

[0304] Example 13 A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, a nitrogen inlet tube, and a dropping funnel was charged with 48.0 parts of the aqueous dispersion containing polymer emulsion particles obtained in Production Example 11 and 26.6 parts of deionized water, and the reaction vessel was heated with stirring using a water bath until the internal temperature reached 57°C.

[0305] While maintaining the internal temperature at 57°C, 0.5 parts of a 20% aqueous solution of 2,2-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride was added to the reaction vessel, and the mixture was stirred for 20 minutes. Thereafter, while maintaining the internal temperature at 57°C, 7.1 parts of deionized water, 1.6 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, trade name: Adeka Reasoap SR-20), 5.0 parts of MMA, 4.0 parts of EHA, 2.0 parts of CHMA, 4.0 parts of St, 0.6 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adeka Stab LA-87), 0.2 parts of HEMA, and an ultraviolet absorbing monomer (Otsuka A mixture of 0.4 parts of methacryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product number: KMB-503), 0.1 part of an oil-soluble ultraviolet absorber (manufactured by ADEKA Corporation, product number: Adeka STAB LA-F70), 0.2 parts of methine yellow dye, and 0.1 parts of anthraquinone purple dye was added dropwise to a reaction vessel over 90 minutes with stirring.

[0306] 120 minutes after the end of the dropwise addition, the reaction vessel was removed from the water bath, and the internal temperature of the reaction vessel was cooled to 40°C or below. 0.1 parts of a preservative (manufactured by DuPont, trade name: KORDEK MLX) was then added to the reaction vessel to obtain an aqueous dispersion containing polymer emulsion particles having a resin layer formed by polymerizing the monomer component for forming the resin layer on the surface of the polymer emulsion particles obtained in Production Example 11. The nonvolatile content of the aqueous dispersion containing polymer emulsion particles having a resin layer obtained above was 35.8% by mass.

[0307] The average particle size of the polymer emulsion particles contained in the obtained aqueous dispersion containing polymer emulsion particles having a resin layer was measured immediately after production in the same manner as above, and was found to be 54 nm.

[0308] Comparative Example 1 A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, a nitrogen inlet tube, and a dropping funnel was charged with 27.9 parts of the aqueous dispersion containing polymer emulsion particles obtained in Production Example 1 and 40.4 parts of deionized water, and the reaction vessel was heated with stirring using a water bath until the internal temperature reached 80°C.

[0309] While maintaining the internal temperature at 80° C., 2.6 parts of a 3.5% aqueous solution of ammonium persulfate was added to the reaction vessel and stirred for 10 minutes. Then, while maintaining the internal temperature at 80° C., a mixture of 9.1 parts of deionized water, 2.5 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, trade name: Adeka Reasoap SR-20), 6.0 parts of MMA, 6.2 parts of EHA, 3.7 parts of CHMA, 0.4 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adekastab LA-87), 0.3 parts of HEMA, 0.6 parts of an ultraviolet absorbing monomer (manufactured by Otsuka Chemical Co., Ltd., trade name: RUVA-93), and 0.1 parts of methacryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product number: KMB-503) was added dropwise to the reaction vessel over 90 minutes with stirring.

[0310] Sixty minutes after the end of the dropwise addition, 0.1 parts of 25% aqueous ammonia solution was added to the reaction vessel to neutralize the contents. Thirty minutes after the end of neutralization, the reaction vessel was removed from the water bath, and the internal temperature of the reaction vessel was cooled to 40°C or below. Then, 0.1 parts of a preservative (manufactured by DuPont, trade name: KORDEK MLX) was added to the reaction vessel to obtain an aqueous dispersion containing polymer emulsion particles having a resin layer formed by polymerizing the resin layer-forming monomer component on the surface of the polymer emulsion particles obtained in Production Example 1. The nonvolatile content of the aqueous dispersion containing polymer emulsion particles having a resin layer obtained above was 26.0% by mass.

[0311] The average particle size of the polymer emulsion particles contained in the obtained aqueous dispersion containing polymer emulsion particles having a resin layer was measured immediately after production in the same manner as above, and was found to be 68 nm. A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, a nitrogen inlet tube, and a dropping funnel was charged with 27.9 parts of the aqueous dispersion containing polymer emulsion particles obtained in Production Example 1 and 40.4 parts of deionized water, and the reaction vessel was heated with stirring using a water bath until the internal temperature reached 80°C.

[0312] While maintaining the internal temperature at 80° C., 2.6 parts of a 3.5% aqueous solution of ammonium persulfate was added to the reaction vessel and stirred for 10 minutes. Then, while maintaining the internal temperature at 80° C., a mixture of 9.1 parts of deionized water, 2.5 parts of a 25% aqueous solution of an anionic emulsifier (manufactured by ADEKA Corporation, trade name: Adeka Reasoap SR-20), 6.0 parts of MMA, 6.2 parts of EHA, 3.7 parts of CHMA, 0.4 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adekastab LA-87), 0.3 parts of HEMA, 0.6 parts of an ultraviolet absorbing monomer (manufactured by Otsuka Chemical Co., Ltd., trade name: RUVA-93), and 0.1 parts of methacryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product number: KMB-503) was added dropwise to the reaction vessel over 90 minutes with stirring.

[0313] Sixty minutes after the end of the dropwise addition, 0.1 parts of 25% aqueous ammonia solution was added to the reaction vessel to neutralize the contents. Thirty minutes after the end of neutralization, the reaction vessel was removed from the water bath, and the internal temperature of the reaction vessel was cooled to 40°C or below. Then, 0.1 parts of a preservative (manufactured by DuPont, trade name: KORDEK MLX) was added to the reaction vessel to obtain an aqueous dispersion containing polymer emulsion particles having a resin layer formed by polymerizing the resin layer-forming monomer component on the surface of the polymer emulsion particles obtained in Production Example 1. The nonvolatile content of the aqueous dispersion containing polymer emulsion particles having a resin layer obtained above was 26.0% by mass.

[0314] The average particle size of the polymer emulsion particles contained in the obtained aqueous dispersion containing polymer emulsion particles having a resin layer was measured immediately after production in the same manner as above, and was found to be 68 nm.

[0315] Comparative Example 2 A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, a nitrogen inlet tube, and a dropping funnel was charged with 27.9 parts of the aqueous dispersion containing polymer emulsion particles obtained in Production Example 8 and 28.0 parts of deionized water, and the reaction vessel was heated with stirring using a water bath until the internal temperature reached 80°C.

[0316] While maintaining the internal temperature at 80°C, 1.8 parts of a 3.5% aqueous solution of ammonium persulfate was added to the reaction vessel and stirred for 10 minutes. Subsequently, while maintaining the internal temperature at 80°C, 13.2 parts of deionized water, 3.0 parts of a 25% aqueous solution of anionic emulsifier (manufactured by ADEKA Corporation, trade name: Adeka Reasoap SR-20), 6.0 parts of MMA, 6.2 parts of EHA, 3.7 parts of CHMA, 0.4 parts of a hindered amine light stabilizer (manufactured by ADEKA Corporation, trade name: Adekastab LA-87), 0.3 parts of HEMA, and 0.4 parts of an ultraviolet absorbing monomer (manufactured by Otsuka Chemical Co., Ltd., trade name: RUVA-93) were added. A mixture of 7 parts of methyl methacrylate, 0.1 parts of methacryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product number: KMB-503), 0.1 parts of an ultraviolet absorber (manufactured by BASF, product name: Tinuvin 400) (manufactured by BASF, product name: Tinuvin (registered trademark) 479) and 0.2 parts of an ultraviolet absorber (manufactured by BASF, product name: Tinuvin (registered trademark) 970) was added dropwise to a reaction vessel over 90 minutes with stirring.

[0317] Sixty minutes after the end of the dropwise addition, 0.1 parts of 25% aqueous ammonia solution was added to the reaction vessel to neutralize the contents. Thirty minutes after the end of neutralization, the reaction vessel was removed from the water bath, and the internal temperature of the reaction vessel was cooled to 40°C or below. Then, 0.1 parts of a preservative (manufactured by DuPont, trade name: KORDEK MLX) was added to the reaction vessel to obtain an aqueous dispersion containing polymer emulsion particles having a resin layer formed by polymerizing the resin layer-forming monomer component on the surface of the polymer emulsion particles obtained in Production Example 8. The nonvolatile content of the aqueous dispersion containing polymer emulsion particles having a resin layer obtained above was 32.0% by mass.

[0318] The average particle size of the polymer emulsion particles contained in the obtained aqueous dispersion containing polymer emulsion particles having a resin layer was measured immediately after production in the same manner as above, and was found to be 180 nm.

[0319] Experimental Example 1 The haze of the polymer emulsion particle-containing aqueous dispersion obtained in Example 1, the polymer emulsion particle-containing aqueous dispersion obtained in Example 2, the polymer emulsion particle-containing aqueous dispersion obtained in Example 3, the polymer emulsion particle-containing aqueous dispersion obtained in Example 4, the polymer emulsion particle-containing aqueous dispersion obtained in Example 5, the polymer emulsion particle-containing aqueous dispersion obtained in Example 6, the polymer emulsion particle-containing aqueous dispersion obtained in Example 7, the polymer emulsion particle-containing aqueous dispersion obtained in Comparative Example 1, and the polymer emulsion particle-containing aqueous dispersion obtained in Comparative Example 2 was measured according to the haze measurement method described below.

[0320] To compare with the polymer emulsion particle-containing aqueous dispersions obtained in each Example, a polymer emulsion particle-containing aqueous dispersion was prepared by adding 1.35 parts of an oil-soluble azo red dye (manufactured by Chuo Synthetic Chemical Co., Ltd., product name: Oil Color Red TR-71) or 1.35 parts of an oil-soluble chromium complex salt red dye to 100 parts of an acrylic resin emulsion (manufactured by Nippon Shokubai Co., Ltd., product name: U-DOUBLE EF-015). However, in all of the polymer emulsion particle-containing aqueous dispersions, the dye precipitated and did not disperse.

[0321] A conventional aqueous dispersion containing polymer emulsion particles was prepared by mixing 100 parts of an acrylic resin emulsion (trade name: U-DOUBLE EF-015, manufactured by Nippon Shokubai Co., Ltd.) with 3.7 parts of an aqueous dispersion of a red pigment (trade name: EMACOL RED3303, manufactured by Sanyo Dye Co., Ltd.) The haze of the conventional aqueous dispersion containing polymer emulsion particles obtained above was measured in the same manner as described above.

[0322] The haze was measured using each of the polymer emulsion particle-containing aqueous dispersions. As a result, the haze value was 0.8 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 1 was used, 1.2 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 2 was used, 0.7 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 3 was used, 0.9 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 4 was used, 1.3 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 5 was used, 0.6 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 6 was used, and 0.7 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 7 was used. When the polymer emulsion particle-containing aqueous dispersion obtained in Example 8 was used, the haze value was 0.9, when the polymer emulsion particle-containing aqueous dispersion obtained in Example 8 was used, the haze value was 1.1, when the polymer emulsion particle-containing aqueous dispersion obtained in Example 9 was used, the haze value was 0.7, when the polymer emulsion particle-containing aqueous dispersion obtained in Example 10 was used, the haze value was 1.3, when the polymer emulsion particle-containing aqueous dispersion obtained in Example 11 was used, the haze value was 0.9, when the polymer emulsion particle-containing aqueous dispersion obtained in Example 12 was used, the haze value was 1.1, and when the polymer emulsion particle-containing aqueous dispersion obtained in Example 13 was used, the haze value was 0.7. In contrast, when the polymer particle-containing aqueous dispersion obtained in Comparative Example 1 was used, the haze value was 0.4, when the polymer particle-containing aqueous dispersion obtained in Comparative Example 2 was used, the haze value was 3.5, and when a conventional polymer emulsion particle-containing aqueous dispersion was used, the haze value was 66.7.

[0323] From the above results, it can be seen that the polymer emulsion particle-containing aqueous dispersions obtained in the respective Examples had significantly lower levels of turbidity than Comparative Example 2 and the conventional polymer emulsion particle-containing aqueous dispersions.

[0324] [Method for measuring haze] Each aqueous dispersion containing acrylic polymer emulsion particles was applied to a glass plate with an applicator so that the thickness of the coating film after drying would be 60 μm, and the coating was formed by drying in a dryer at 80°C for 2 hours to obtain a test plate.

[0325] The haze of the coating surface of the test plate obtained above was measured using a spectrophotometer (manufactured by Konica Minolta, Inc., product number: CM-3700A) in accordance with the conditions specified in ASTM-D-1003-97-C.

[0326] Experimental Example 2 Weather resistance was evaluated according to the following weather resistance evaluation method using the polymer emulsion particle-containing aqueous dispersion obtained in Example 2, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 4, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 5, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 6, the polymer emulsion particle-containing aqueous dispersion obtained in Example 7, the polymer emulsion particle-containing aqueous dispersion obtained in Example 8, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 9, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 10, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 11, the polymer emulsion particle-containing aqueous dispersion obtained in Example 12, the polymer emulsion particle-containing aqueous dispersion obtained in Example 13, the polymer emulsion particle-containing aqueous dispersion obtained in Comparative Example 1, and the polymer emulsion particle-containing aqueous dispersion obtained in Comparative Example 2.

[0327] [Weather resistance evaluation method] On an aluminum plate (manufactured by Nippon Test Panel Co., Ltd., length: 150 mm, width: 70 mm, thickness: 0.8 mm), the polymer emulsion particle-containing aqueous dispersion obtained in Example 2, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 4, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 5, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 6, the polymer emulsion particle-containing aqueous dispersion obtained in Example 7, the polymer emulsion particle-containing aqueous dispersion obtained in Comparative Example 1, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 8, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 9, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 10, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 11, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 12, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 13, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 14, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 15, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 16, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 17, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 18, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 19, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 20, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 21, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 22, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 23, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 24, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 25, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 26, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 27, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 28, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 29, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 30, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 3 The polymer emulsion particle-containing aqueous dispersion obtained in Example 13, the polymer emulsion particle-containing aqueous dispersion obtained in Comparative Example 2, and the polymer emulsion particle-containing aqueous dispersion obtained in Comparative Example 2 were each applied with an applicator so that the dried coating thickness would be 40 μm, and after drying for 2 hours in a dryer at 80°C, a mixture of 10 parts of an ultraviolet-blocking coating agent (manufactured by Nippon Shokubai Co., Ltd., product name: Hals Hybrid UV-G101), 6 parts of toluene, and 2 parts of 6-[3-(6-isocyanatohexyl)-2,4-dioxo-1,3-diazetidin-1-yl]hexyl 6-isocyanatohexylcarbamate was applied to each coating with an applicator within 1 hour from the start of mixing so that the dried coating thickness would be 40 μm, and the mixture was dried in air at 23°C for 24 hours to form a coating, yielding a test panel with coating structure A.

[0328] Furthermore, the polymer emulsion particle-containing aqueous dispersion obtained in Example 8, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 10, the polymer emulsion particle-containing aqueous dispersion example obtained in Example 11, the polymer emulsion particle-containing aqueous dispersion obtained in Example 12, and the polymer emulsion particle-containing aqueous dispersion obtained in Example 13 were each applied with an applicator so that the thickness of the coating film after drying would be 40 μm, and after drying for 2 hours in a dryer at 80° C., an ultraviolet-cut coating agent (manufactured by Nippon Shokubai Co., Ltd., trade name: HALS Hybrid) was applied onto each coating film. A mixture of 10 parts of [UV-G101], 6 parts of toluene, 0.12 parts of a methine yellow dye, 0.1 part of an anthraquinone purple dye, 0.01 parts of an antioxidant [manufactured by ADEKA Corporation, trade name: Adeka STAB AO-412S], and 2 parts of 6-[3-(6-isocyanatohexyl)-2,4-dioxo-1,3-diazetidin-1-yl]hexyl 6-isocyanatohexylcarbamate was applied with an applicator within 1 hour from the start of mixing so that the thickness of the dried coating would be 40 μm. The mixture was then dried in air at 23°C for 24 hours to form a coating, yielding a test panel with Coating Structure B.

[0329] The color difference (L0, a0, b0) of the coating surface of the test plate obtained above was measured using a color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd., trade name: Spectroscopic Color Difference Meter SE-2000).

[0330] Next, after irradiating the test plate with ultraviolet light for 504 hours under the following ultraviolet irradiation conditions, the color difference (L1, a1, b1) of the coating surface of the test plate was measured, and the color change (ΔE) due to ultraviolet light irradiation was calculated using the formula: ΔE=[(L1-L0) 2 +(a1-a0) 2 +(b1-b0) 2 ] 1 / 2 was calculated based on the following.

[0331] As a result, for each test panel of Coating Film Configuration A, the viscosity was 9.8 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 2 was used, 3.1 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 4 was used, 2.4 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 5 was used, 2.1 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 6 was used, and 8.8 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 7 was used. The viscosity was 2.3 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 8 was used, 1.9 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 9 was used, 5.2 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 10 was used, 6.0 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 11 was used, 5.6 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 12 was used, and 5.5 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 13 was used. For the test panel of coating film configuration B, the color change (ΔE) was 1.9 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 8 was used, 0.9 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 10 was used, 1.7 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 11 was used, 2.1 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 12 was used, and 2.8 when the polymer emulsion particle-containing aqueous dispersion obtained in Example 13 was used. In contrast, the color change (ΔE) due to ultraviolet light irradiation was 27 when the polymer emulsion particle-containing aqueous dispersion obtained in Comparative Example 1 was used, and 29 when the polymer emulsion particle-containing aqueous dispersion obtained in Comparative Example 2 was used.

[0332] From the above results, it was confirmed that the aqueous dispersions containing polymer emulsion particles obtained in the examples were superior in weather resistance to the comparative examples.

[0333] [Ultraviolet irradiation conditions] Ultraviolet light was irradiated under the following conditions using a Metaling Weather Meter M6T manufactured by Suga Test Instruments Co., Ltd. Cycle: 16 hours of light, 6 hours of darkness Irradiation intensity: 0.50kWh BPT temperature: 63℃ during irradiation Relative humidity: 50% when illuminated, 98% when dark

Claims

1. The core-shell particles have an average particle size of 10 nm or more and 200 nm or less, a core containing a colorant and a polymer A, and a shell containing a visible light absorbing material and a polymer B, and contain a fatty acid ester having 18 or more carbon atoms.

2. 2. The core-shell particle of claim 1, wherein the colorant is a dye.

3. 3. The core-shell particle according to claim 2, wherein the solubility of the dye in 1000 g of water at room temperature (23° C.) is less than 10 g.

4. 4. The core-shell particle according to claim 1, wherein the polymer A and / or the polymer B is a (meth)acrylic polymer.

5. the polymer A is a polymer having a structure derived from the monomer A, 5. The core-shell particle according to claim 1, wherein the monomer A comprises an alkyl(meth)acrylate having an alkyl group having 4 to 8 carbon atoms.

6. The core-shell particle according to claim 5 , wherein the monomer A further comprises methyl (meth)acrylate.

7. An aqueous dispersion comprising the core-shell particles according to any one of claims 1 to 6.

8. A vehicle paint comprising the aqueous dispersion of claim 7.

9. A method for producing core-shell particles obtained through the following steps (1) to (3): A method for producing core-shell particles, wherein the following monomer A and monomer B contain an ethylenically unsaturated double bond-containing monomer: (1) Step 1: mixing a colorant, a monomer A, a fatty acid ester, a nonionic surfactant, and an aqueous medium, heating the resulting mixture under stirring to a temperature equal to or higher than the phase inversion onset temperature of the mixture and lower than the boiling point of the aqueous medium, and then cooling the mixture to a temperature lower than the phase inversion onset temperature of the mixture; (2) Step 2, after Step 1, in which monomer A is polymerized; (3) Step 3: After step 2, a visible light absorber and monomer B are added, and monomer B is polymerized.

10. The method for producing core-shell particles according to claim 9, wherein a nonionic surfactant is used in step 1.

11. The method for producing core-shell particles according to claim 9 or 10, wherein the nonionic surfactant is used in an amount of 1 part by mass or more and 60 parts by mass or less per 100 parts by mass of the total amount of the colorant, monomer A, fatty acid ester, and nonionic surfactant.

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