Coated plate-like titanic acid particles, their production method and use

Abstract

Provided are: coated flaky titanic acid particles, which can form a design coating film with a good silky texture and shadowed appearance when flaky titanic acid is applied to an organic solvent-based paint and, which can also sufficiently suppress discoloration (yellowing) of the coating film even in a relatively severe environment, such as prolonged exposure to ultraviolet light; and a production method therefor.　The surface of the flaky titanic acid particles has an oxide and / or hydroxide of aluminum, and an anionic surfactant present thereon. Preferably, the anionic surfactant is a hydrocarbon-based anionic surfactant having 5 or more carbon atoms in the main chain or a fluorinated anionic surfactant having 4 or more carbon atoms. Said production method comprises: a step for maintaining an aqueous slurry, which contains flaky titanic acid particles and an aluminum source, at a temperature of 50-95°C inclusive and at a pH of 5-12 inclusive to treat the surface of the flaky titanic acid particles with an oxide and / or hydroxide of aluminum; and a subsequent step for mixing the obtained flaky titanic acid and an anionic surfactant in a solution.

Description

[Technical Field]

[0001] The present invention relates to coated plate-like titanic acid particles, a method for producing the same, and uses thereof. [Background technology]

[0002] Brilliant paints that impart design features to the surface of articles are known. Examples of brilliant paints include brilliant pigments in which a titanium oxide coating layer is applied to the surface of a scaly substrate such as natural mica, synthetic mica, or scaly alumina. Conventional brilliant pigments have a strong brilliance (metallic shine) and a granular appearance (a design in which each particle appears to sparkle independently).

[0003] In recent years, designs that have a more luxurious feel, such as a silky look, with a deep, subdued, and delicate luster like silk with reduced particle content (a seamless, smooth design like silk), have been proposed. Plate-like titanic acid is known as a brilliant pigment that imparts a silky look (for example, Patent Document 1).

[0004] Plate-like titanic acid particles have hydrophilic surfaces and can be easily applied to water-based paints. However, their application to organic solvent-based paints is not easy, but various studies are being conducted. For example, Patent Document 2 describes an organic solvent dispersion containing platy titanic acid, an organic solvent, and a primary amine having a linear hydrocarbon group with six or more carbon atoms. In an organic solvent-based paint using such an organic solvent dispersion, the platy titanic acid can be stably dispersed in the paint. Therefore, a glossy coating film formed using this organic solvent-based paint can sufficiently ensure a silky feel and a sense of shadow (the difference between the brightness of highlights and shades when light hits the coating film), creating a unique design. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 159923 [Patent Document 2] Japanese Patent Application Publication No. 2020-23419 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the technology described in Patent Document 2 above has concerns about discoloration (yellowing) of the coating film due to prolonged exposure to ultraviolet light, etc. While yellowing of the coating film can be suppressed without using the above-mentioned primary amine, in this case the dispersion effect of the platy titanic acid in the organic solvent is lost, resulting in insufficient shading of the coating film. For these reasons, there is a need for a technology that can more reliably achieve both a silky feel and shading effect, as well as preventing discoloration (yellowing) of the coating film, when using platy titanic acid in organic solvent-based paints. [Means for solving the problem]

[0007] The present inventors have conducted extensive research in light of the above-mentioned problems of the prior art. They have found that the dispersion stability of plate-like titanate particles in an organic solvent can be sufficiently ensured by adding an aluminum oxide and / or hydroxide and a specific surfactant to the surface of the plate-like titanate particles. Furthermore, they have found that the above-mentioned problems can be solved by preparing an organic solvent-based paint using this organic solvent dispersion and applying it to an object to form a coating film, thereby completing the present invention.

[0008] That is, the present invention is (1) Coated plate-like titanic acid particles in which aluminum oxide and / or hydroxide and an anionic surfactant are present on the surface of the plate-like titanic acid particles; (2) The coated plate-like titanate particles according to (1), wherein the anionic surfactant is a hydrocarbon-based anionic surfactant having 5 or more carbon atoms in the main chain and / or a fluorine-based anionic surfactant having 4 or more carbon atoms. (3) The coated plate-like titanate particles according to (1) or (2), wherein the anionic surfactant is present on the aluminum oxide and / or hydroxide on the surface of the plate-like titanate particles. (4) The coated plate-like titanate particles according to any one of (1) to (3), wherein the content of the anionic surfactant is 0.01% by mass or more and 30% by mass or less relative to the plate-like titanate. (5) The coated plate-like titanate particles according to any one of (1) to (4), wherein the content of the aluminum oxide and / or hydroxide is 1% by mass or more and 30% by mass or less in terms of Al2O3 relative to the plate-like titanate. (6) A decorative pigment containing the coated plate-like titanate particles according to any one of (1) to (5). (7) An organic solvent dispersion containing the coated plate-like titanate particles according to any one of (1) to (5) and an organic solvent. (8) A coating composition comprising the coated plate-like titanate particles according to any one of (1) to (5) and a resin component. (9) A plastic composition comprising the coated plate-like titanate particles according to any one of (1) to (5) and a resin component. (10) A method for producing coated plate-like titanic acid particles, which comprises a step of mixing, in a solution, plate-like titanic acid having aluminum oxide and / or hydroxide present on the particle surface with an anionic surfactant; (11) The method for producing coated plate-like titanate particles according to (10), wherein the anionic surfactant is a hydrocarbon-based anionic surfactant having a main chain carbon number of 5 or more and / or a fluorine-based anionic surfactant having a main chain carbon number of 4 or more. (12) A method for producing coated plate-like titanate particles according to (10) or (11), which comprises a step of causing the aluminum oxide and / or hydroxide to be present on the surface of plate-like titanate particles, and the step comprises maintaining the temperature of an aqueous slurry containing the plate-like titanate particles and an aluminum source at 50°C or higher and 95°C or lower, and maintaining the pH of the aqueous slurry at 5 or higher and 12 or lower. And so on. [Effects of the Invention]

[0009] According to the present invention, plate-like titanic acid can be applied to organic solvent-based paints, and a designable coating film with both a silky feel and a good sense of shading can be realized. Moreover, discoloration (yellowing) of the coating film is sufficiently suppressed even when placed in a relatively severe environment, such as exposure to ultraviolet light for a long period of time, so that the plate-like titanic acid particles are useful as particles to be blended into organic solvent-based automotive paints and plastics. DETAILED DESCRIPTION OF THE INVENTION

[0010] The coated plate-like titanate particles of the present invention have aluminum oxide and / or hydroxide and an anionic surfactant present on the particle surface of the plate-like titanate particles, preferably aluminum oxide and / or hydroxide and a hydrocarbon-based anionic surfactant having a main chain of 5 or more carbon atoms and / or a fluorine-based anionic surfactant having 4 or more carbon atoms present on the particle surface of the plate-like titanate particles. The phrase "presence of the aluminum oxide and / or hydroxide or the anionic surfactant on the particle surface" of the plate-like titanate refers to a state in which the aluminum oxide and / or hydroxide or the anionic surfactant is present by coating the particle surface of the plate-like titanate particles, adhering or adsorbing to the particle surface of the plate-like titanate particles, or reacting with the particle surface of the plate-like titanate particles. The aluminum oxide and / or hydroxide or the anionic surfactant may coat the entire particle surface of the plate-like titanate particles, or may be present on at least a portion of the particle surface of the plate-like titanate particles. In this application, in accordance with the above definition, plate-like titanate particles having aluminum oxide and / or hydroxide and anionic surfactant present on the surface thereof are called coated plate-like titanate particles, and are distinguished from the plate-like titanate particles that constitute them (i.e., the plate-like titanate particles before aluminum oxide and / or hydroxide and anionic surfactant are present on the surface).

[0011] The coated plate-like titanate particles of the present invention and the plate-like titanate particles that constitute them have a "plate-like" shape. The term "plate-like" encompasses shapes such as thin flakes, sheets, flakes, and scales, and refers to a shape in which the ratios of width and length to thickness are relatively large.

[0012] "Titanic acid" refers to a compound composed of Ti, O, and H atoms, and may contain impurities derived from the manufacturing method of titanic acid, as well as various trace elements (e.g., Li, Na, K, Rb, Cs, etc.). Plate-like titanic acid can have a variety of crystalline structures, but titanic acid with a layered crystalline structure is preferred. Various layered crystalline structures exist, but for example, titanic acid with a lepidocrocite structure, in which TiO octahedra share edges to form sheets extending two-dimensionally along the a- and c-axes, with cations contained between the sheets, can be used. The crystalline structure of titanic acid can be confirmed by powder X-ray diffraction.

[0013] The plate-like titanate particles preferably have a median diameter (D50) in the range of 10 μm to 40 μm, more preferably 15 μm to 30 μm, in the volume particle size distribution measured by laser diffraction / scattering. This makes it easier to obtain a coating film that exhibits a good sense of shading and a silky feel. The plate-like titanate particles preferably have a cumulative 10% particle diameter (D10) in the volume particle size distribution measured by laser diffraction / scattering. This makes it possible to sufficiently reduce the proportion of fine particles, thereby preventing a decrease in the sense of shading of the coating film.

[0014] The plate-like titanate particles preferably have a cumulative 90% particle size (D90) of 70 μm or less, more preferably 60 μm or less, in the volume particle size distribution measured by the laser diffraction / scattering method. This sufficiently reduces the proportion of coarse particles present, thereby suppressing the appearance of a grainy texture in the coating film. The particle size distribution of the plate-like titanate particles measured by the laser diffraction / scattering method is measured using a laser diffraction / scattering particle size distribution analyzer (LA-950, manufactured by Horiba, Ltd.) with a refractive index set to 2.50.

[0015] The average thickness of the plate-like titanate particles is preferably in the range of 0.05 μm to 0.4 μm, more preferably in the range of 0.05 μm to 0.3 μm. The average thickness is determined by preparing a coating film containing the plate-like titanate particles, cutting the coating film with a microtome, observing the cross section with an electron microscope, and averaging the thickness measurements of 50 or more randomly selected particles.

[0016] The coated plate-like titanate particles of the present invention have aluminum oxide and / or hydroxide on the surface of the plate-like titanate particles. The aluminum oxide and / or hydroxide may coat the surface of the plate-like titanate particles or may be scattered in island-like patterns on the surface of the plate-like titanate particles. Aluminum oxide is sometimes called alumina. Aluminum hydroxide includes alumina hydrate and hydrous alumina. Examples of the crystalline structure of aluminum hydroxide include boehmite, gibbsite, pseudoboehmite, and bayerite. Multiple types of aluminum hydroxides with different crystalline structures may be mixed. Of course, aluminum oxide and hydroxide may be mixed. The crystalline structure of aluminum can be confirmed by powder X-ray diffraction. It is understood that the aluminum oxide and / or hydroxide function as a scaffold for adsorbing anionic surfactants to the surface of the plate-like titanate particles.

[0017] The content of aluminum oxide and / or hydroxide is preferably 1% by mass to 30% by mass, calculated as Al2O3, relative to the platy titanate. A content of 1% by mass or more is preferred from the viewpoint of allowing a sufficient amount of anionic surfactant to be adsorbed onto the surface of the platy titanate particles via the aluminum oxide and / or hydroxide. Increasing the content of aluminum oxide and / or hydroxide increases the adsorption of the anionic surfactant, but above a certain level (specifically, approximately 30% by mass), the effect (specifically, improving the dispersibility of the coated platy titanate particles in organic solvents) plateaus. Therefore, from the viewpoint of efficient content, a content of 30% by mass or less is preferred. The content of the aluminum oxide and / or hydroxide is more preferably 3% by mass to 25% by mass, and even more preferably 5% by mass to 20% by mass, calculated as Al2O3, relative to the platy titanate.

[0018] The coated plate-like titanate particles of the present invention have an anionic surfactant present on the surface of the plate-like titanate particles in addition to an aluminum oxide and / or hydroxide. More preferably, a hydrocarbon-based anionic surfactant with a main chain of 5 or more carbon atoms and / or a fluorine-based anionic surfactant with a main chain of 4 or more carbon atoms is present. The anionic surfactant is a surfactant having an anionic hydrophilic group. The anionic hydrophilic group acts on the basic sites of the aluminum oxide and / or hydroxide, adsorbing or reacting with them, thereby being present on the surface of the plate-like titanate particles via the aluminum oxide and / or hydroxide. In this state, the anionic surfactant is present on the aluminum oxide and / or hydroxide on the surface of the plate-like titanate particles. Furthermore, some of the anionic surfactant may be present directly on the surface of the plate-like titanate particles by adsorbing or reacting with them. The hydrophobic group (e.g., hydrocarbon group or fluoroalkyl group) of the anionic surfactant is understood to increase the affinity for organic solvents, thereby improving the dispersibility of the coated plate-like titanate particles in organic solvents.

[0019] The anionic surfactant is not particularly limited as long as it can act on the basic points of aluminum oxide and / or hydroxide. Depending on the chemical structure of the hydrophilic portion (hydrophilic group), surfactants such as carboxylic acid type, sulfonic acid type, sulfate ester type, and phosphate ester type can be used as such anionic surfactants. Depending on the hydrophobic group contained in the anionic surfactant, it can be classified into hydrocarbon-based anionic surfactants having a hydrocarbon group and fluorine-based anionic surfactants having a fluoroalkyl group.

[0020] The hydrocarbon-based anionic surfactant preferably has 5 or more carbon atoms in its molecular structure (the backbone portion with the largest carbon number). While the main chain is primarily composed of carbon atoms, it may contain atoms other than carbon (such as oxygen, nitrogen, or sulfur atoms). The main chain may also contain double bonds between carbon atoms or benzene rings. While the main chain may have side chains (branch portions with fewer carbon atoms than the main chain), it is preferable for the surfactant to have no side chains (linear chains). The hydrocarbon-based anionic surfactant preferably has 8 or more carbon atoms in its main chain, and more preferably 12 or more carbon atoms in its main chain. This enhances the affinity of the platelet titanic acid with organic solvents, further improving the dispersibility of the coated platelet titanic acid particles in organic solvents. The hydrocarbon-based anionic surfactant preferably has 20 or less carbon atoms in its main chain, and more preferably has 18 or less carbon atoms in its main chain.

[0021] Specific examples of hydrocarbon-based anionic surfactants that can be used include the following: The hydrocarbon-based anionic surfactants can be used alone or in combination of two or more.

[0022] (1) Carboxylic acid type Caproic acid, heptanoic acid, caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, margaric acid, stearic acid, oleic acid, and sodium or potassium salts thereof.

[0023] (2) Sulfonic acid type Examples of suitable sulfonates include sodium hexanesulfonate, sodium heptylsulfonate, sodium octylsulfonate, sodium norylsulfonate, sodium decylsulfonate, sodium undecylsulfonate, sodium laurylsulfonate, sodium tridecylsulfonate, sodium myristylsulfonate, sodium pentasulfonate, sodium cetylsulfonate, sodium heptadecylsulfonate, sodium stearylsulfonate, dodecylbenzenesulfonic acid, sodium dodecylbenzenesulfonate, and potassium salts thereof, disodium laureth sulfosuccinate, and diethylhexyl sodium sulfosuccinate.

[0024] (3) Sulfate ester type Examples of suitable hydroxypropyl ethers include sodium hexyl sulfate, sodium heptyl sulfate, sodium octyl sulfate, sodium noryl sulfate, sodium decyl sulfate, sodium undecyl sulfate, sodium lauryl sulfate, sodium tridecyl sulfate, sodium myristyl sulfate, sodium pentadecyl sulfate, sodium cetyl sulfate, sodium heptadecyl sulfate, sodium stearyl sulfate, polyoxyethylene lauryl ether sodium sulfate, polyoxyethylene tridecyl ether sodium sulfate, polyoxyethylene myristyl ether sodium sulfate, polyoxyethylene pentadecyl ether sodium sulfate, polyoxyethylene cetyl ether sodium sulfate, polyoxyethylene heptadecyl ether sodium sulfate, polyoxyethylene cetyl ether sodium sulfate, polyoxyethylene stearyl ether sodium sulfate, polyoxyethylene oleyl ether sodium sulfate, and potassium salts thereof, ammonium lauryl sulfate, and ammonium laureth sulfate.

[0025] (4) Phosphate ester type Hexyl phosphate, heptyl phosphate, octyl phosphate, noryl phosphate, decyl phosphate, isodecyl phosphate, undecyl phosphate, lauryl phosphate, tridecyl phosphate, myristyl phosphate, pentadecyl phosphate, cetyl phosphate, heptadecyl phosphate, stearyl phosphate, oleyl phosphate, and their sodium or potassium salts, 2-ethylhexyl acid phosphate, isodecyl acid phosphate, isotridecyl acid phosphate, isostearyl acid phosphate, lauryl acid phosphate, myristyl acid phosphate, cetyl acid phosphate, stearyl acid phosphate phosphate, oleyl acid phosphate, tetracosyl acid phosphate, bis(2-ethylhexyl) phosphate, polyoxyethylene lauryl ether phosphate, polyoxyethylene tridecyl ether phosphate, polyoxyethylene myristyl ether phosphate, polyoxyethylene pentadecyl ether phosphate, polyoxyethylene cetyl ether phosphate, polyoxyethylene heptadecyl ether phosphate, polyoxyethylene cetyl ether phosphate, polyoxyethylene stearyl ether phosphate, polyoxyethylene oleyl ether phosphate, and sodium or potassium salts thereof.

[0026] The content of the hydrocarbon-based anionic surfactant is preferably 0.01% by mass or more and 30% by mass or less, more preferably 0.5% by mass or more and 30% by mass or less, and even more preferably 5% by mass or more and 25% by mass or less, relative to the platy titanic acid. This level of content allows a sufficient amount of anionic surfactant (hydrocarbon chain of anionic surfactant) to be present on the surface of the platy titanic acid particles. As a result, the coated platy titanic acid particles, in which such anionic surfactant is present on the surface of the platy titanic acid particles, are well dispersed in organic solvents or organic solvent-based paints, achieving a good silky feel and a good sense of shadow.

[0027] The fluorine-based anionic surfactant is an anionic surfactant having a fluoroalkyl group in which hydrogen atoms in the alkyl chain are substituted with fluorine atoms. The number of fluorine atoms substituted in the fluoroalkyl group is not particularly limited, but a perfluoroalkyl group in which all hydrogen atoms are substituted with fluorine is preferred. While a side chain (a branch having fewer carbon atoms than the main chain) may be present in the main chain, a side chain-free (linear) surfactant is preferred. The fluorine-based anionic surfactant preferably has 4 or more carbon atoms, more preferably 6 or more carbon atoms. This increases the affinity of the platelet titanic acid with organic solvents, further improving the dispersibility of the coated platelet titanic acid particles in organic solvents. On the other hand, the fluorine-based anionic surfactant preferably has 8 or less carbon atoms.

[0028] Specific examples of fluorine-based anionic surfactants that can be used include the following. The fluorine-based anionic surfactants can be used alone or in combination of two or more. They can also be used in combination with the hydrocarbon-based anionic surfactants described above.

[0029] (1) Carboxylic acid type Perfluorobutanoic acid, perfluoropentanoic acid, perfluorohexanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorolauric acid, and sodium or potassium salts thereof.

[0030] (2) Sulfonic acid type Perfluorobutanesulfonic acid, perfluoropentanesulfonic acid, perfluorohexanesulfonic acid, perfluorooctane sulfonic acid, perfluorononanesulfonic acid, perfluorolaurinsulfonic acid, and lithium, sodium or potassium salts thereof.

[0031] (3) Phosphate ester type Perfluorohexyl phosphate, perfluorooctyl phosphate, perfluorolauryl phosphate and their sodium or potassium salts, 2-(perfluorohexyl)ethyl phosphate diethanolamine salt, etc.

[0032] The content of the fluorine-based anionic surfactant is preferably 0.01% by mass or more and 30% by mass or less, and more preferably 0.05% by mass or more and 10% by mass or less, relative to the platy titanic acid. This level of content allows a sufficient amount of anionic surfactant (fluoroalkyl group of anionic surfactant) to be present on the surface of the platy titanic acid particles. As a result, the coated platy titanic acid particles, in which such anionic surfactant is present on the surface of the platy titanic acid particles, are well dispersed in organic solvents or organic solvent-based paints, achieving a good silky feel and a good sense of shadow.

[0033] The coated plate-like titanate particles of the present invention as described above can be used as a design pigment, and by incorporating them into paint to form a coating film, a design coating film with both a silky feel and a good sense of shading can be realized. Moreover, even when placed in a relatively severe environment, such as exposure to ultraviolet light for a long period of time, discoloration (yellowing) of the coating film can be sufficiently suppressed, so that the coated plate-like titanate particles can withstand long-term use outdoors. Furthermore, the coated plate-like titanate particles of the present invention can be used as a filler, and in particular, their plate-like shape can be used to form a protective layer on the surface of an object.

[0034] The coated plate-like titanate particles of the present invention can be mixed with an organic solvent to form an organic solvent dispersion using a conventional stirrer, a dispersing machine such as a colloid mill, a ball mill, or a bead mill, a shaker, a paint conditioner, a shaker, a disperser, or the like.

[0035] The organic solvent can be appropriately selected depending on the application. For example, Alcohol-based (ethanol, isopropyl alcohol, 2-butanol, glycerin, ethylene glycol, propylene glycol, etc.), Esters (ethyl acetate, propyl acetate, glycerin fatty acid esters, etc.), Polyethers (polyethylene glycol, polytetramethylene oxide, etc.), Carboxylic acids (acetic acid, propionic acid, lauric acid, stearic acid, lactic acid, etc.), Hydrocarbons (hexane, heptane, octane, decane, liquid paraffin, etc.), Aromatic hydrocarbons (benzene, toluene, xylene, naphthalene, etc.), Amides (dimethyl sulfoxide, acetanilide, etc.), Ketones (acetone, diethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), Halogen-based (methylene chloride, chloroform, tetrachloroethylene, etc.), Examples include carbonates (ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, etc.). Other examples include acetonitrile, mineral spirits, diesel, kerosene, crude oil, salad oil, soybean oil, castor oil, fluorine-modified oil, and lacquer thinner. These can be used alone or in combination. Organic compounds containing reactive functional groups, such as methyl acrylate and methyl methacrylate, are also suitable.

[0036] In the organic solvent dispersion of the present invention, the content of the coated plate-like titanate particles can be appropriately set, preferably from about 1 to 50% by mass, more preferably from about 5 to 40% by mass.

[0037] In addition to the coated plate-like titanate particles and the organic solvent, the organic solvent dispersion of the present invention may contain various additives such as dispersants, surface conditioners (leveling agents, wettability improvers), antifoaming agents, colorants, extenders, antifungal agents, curing aids, thickeners, and anti-settling agents, as well as fillers, as third components, within a range that does not impair the effects of the present invention. Dispersants include: (1) Surfactants ((a) anionic (carboxylates, carboxylate ester salts, sulfate ester salts, sulfonates, phosphates, phosphate ester salts, etc.), (b) cationic (alkylamine salts, alkylamine type, etc.), (c) nonionic (ether type, alcohol ester type, ether ester type, ester type, nitrogen-containing type, etc.), etc. (2) Silicone-based dispersants (such as alkyl-modified polysiloxanes and polyoxyalkylene-modified polysiloxanes). The surface conditioner controls the surface tension of the organic solvent dispersion to prevent defects such as repelling and craters, and examples thereof include acrylic surface conditioners, vinyl surface conditioners, silicone surface conditioners, and fluorine surface conditioners. The amount of the third component added can be adjusted appropriately. For example, when the surfactant or silicone dispersant is used as the dispersant, the amount is preferably about 0.005% by mass to about 5.0% by mass, and more preferably about 0.01% by mass to about 2.0% by mass, based on the mass of the coated plate-like titanate particles. The silicone surface conditioner can be used as the surface conditioner, and the amount is preferably about 0.005% by mass to about 5.0% by mass, and more preferably about 0.01% by mass to about 2.0% by mass, based on the mass of the coated plate-like titanate particles.

[0038] The coating composition of the present invention includes, in addition to the coating composition, what is called an ink composition, which contains the above-mentioned coated plate-like titanate particles and a resin component. Specifically, the following resin components can be appropriately used. (1) Inorganic resins ((a) polymerizable silicon compounds (hydrolyzable silanes or their hydrolysis products or their partial condensates, organopolysiloxanes, etc.), (b) metal alkoxides, etc.) (2) Organic resins (alkyd resins, acrylic resins, polyester resins, epoxy resins, amino resins, fluorine resins, modified silicone resins, urethane resins, vinyl resins, etc.) These resin components may be organic solvent-soluble or non-aqueous dispersion (NAD), and the curing method may be heat-curing, room temperature-curing, ultraviolet-curing, electron beam-curing, or the like, without any particular limitation. The content of the coated platy titanate particles in the coating composition can be appropriately set, and the content of the coated platy titanate particles in the coating composition is preferably about 1% by mass or more and 50% by mass or less, and more preferably about 5% by mass or more and 40% by mass or less.

[0039] In addition to the coated platelet titanate particles and resin component, the coating composition of the present invention may contain the above-mentioned organic solvent, and depending on the purpose, various additives such as colorants such as organic pigments, inorganic pigments, and dyes, extenders, surfactants, plasticizers, curing aids, drying agents, antifoaming agents, thickeners, emulsifiers, flow adjusters, anti-skinning agents, color-separation inhibitors, UV absorbers, and anti-fungal agents, as well as fillers. These raw materials can be mixed according to known recipes to form a coating composition. Furthermore, a two-component coating can be prepared in which the curing agent, curing aid, and curable resin component are prepared as separate curing liquids and mixed during application.

[0040] By applying the coating composition of the present invention to a substrate by a known method, a coating film can be obtained that exhibits a good silky feel and a sense of shading, and also has excellent yellowing resistance. Specifically, common methods such as spin coating, spray coating, roller coating, dip coating, flow coating, knife coating, electrostatic coating, bar coating, die coating, brush coating, and dripping can be used without limitation. The tool used to apply the coating composition can be appropriately selected from known tools such as a spray gun, roller, brush, bar coater, doctor blade, etc.

[0041] The plastic composition of the present invention contains the coated plate-like titanate particles of the present invention and a resin component. Examples of the resin component include, but are not limited to, the following. Furthermore, two or more of the following resin components can be used in combination to improve physical properties such as impact resistance, scratch resistance, chemical resistance, and flowability.

[0042] Resin components used in the plastic composition include: (1) General-purpose plastics ((a) polyolefin resins (polyethylene, polypropylene, etc.), (b) polyvinyl chloride resins, (c) acrylonitrile butadiene styrene resins, (d) polystyrene resins, (e) methacrylic resins, (f) polyvinylidene chloride resins, etc.), (2) Engineering plastics ((a) polycarbonate resin, (b) polyethylene terephthalate resin, (c) polyamide resin, (d) polyacetal resin, (e) modified polyphenylene ether, (f) fluororesin, etc.), (3) Super engineering plastics ((a) polyphenylene sulfide resin (PPS), (b) polysulfone resin (PSF), (c) polyethersulfone resin (PES), (d) amorphous polyarylate resin (PAR), (e) liquid crystal polymer (LCP), (f) polyetheretherketone resin (PEEK), (g) polyamideimide resin (PAI), (h) polyetherimide resin (PEI)), Examples include:

[0043] The blending ratio of the coated plate-like titanate particles to the resin component is not particularly limited, but is usually preferably 1 part by mass to 80 parts by mass, more preferably 1 part by mass to 60 parts by mass, relative to 100 parts by mass of the resin component, and in the case of a masterbatch, is preferably 10 parts by mass to 900 parts by mass, more preferably 50 parts by mass to 500 parts by mass. Depending on the application, various additives known to those skilled in the art, such as reinforcing materials such as glass fibers, stabilizers, dispersants, lubricants, antioxidants, UV absorbers, and fillers, may also be added.

[0044] These plastic compositions are obtained by blending the coated platelet titanate particles with a molten resin component using a kneader, which may be a commonly used kneader, such as a single-screw extruder, a twin-screw extruder, an intensive mixer such as a Banbury mixer, or a roll molding machine.

[0045] The plastic composition containing the coated platelet titanate particles obtained in the kneader can be molded by known methods. In particular, molding by a method that applies a load that orients the coated platelet titanate particles in the resin can enhance the designability attributable to the coated platelet titanate particles. Examples of such molding methods include blow molding and compression molding. The molded product may also be heated and stretched. This method can also enhance the designability attributable to the coated platelet titanate particles.

[0046] The method for producing the coated plate-like titanate particles of the present invention will be described below. The coated plate-like titanate particles of the present invention are produced by causing aluminum oxide and / or hydroxide to be present on the surface of plate-like titanate particles and then treating them with an anionic surfactant. The plate-like titanate used as the raw material can be produced, for example, as follows.

[0047] (Production of plate-shaped titanic acid particles) First, a metal titanate powder is produced. The raw materials for the metal titanate powder are a carbonate or hydroxide of an alkali metal, such as lithium, sodium, potassium, rubidium, or cesium, and titanium oxide. The carbonate or hydroxide of two different alkali metals (M and M') is used as the alkali metal carbonate or hydroxide. The carbonate or hydroxide of two different alkali metals (M and M') and titanium oxide are mixed, preferably in a molar ratio of M / M' / Ti of 3 / 1 / 5 to 3 / 1 / 11, and fired at approximately 1050°C to 1200°C. Other firing conditions, such as the heating and cooling rate, firing time, and firing atmosphere, are not particularly limited and may be set appropriately. If necessary, the fired product is crushed to obtain a metal titanate powder.

[0048] The obtained mixed alkali metal titanate powder has Ti in the host skeleton. 4+ A compound of the formula M in which a part of the sites is replaced with an alkali metal ion different from the interlayer alkali metal x [M' x / 3 Ti 2-x / 3]O4 (where M and M' are different alkali metals, and x is 0.50 to 1.0). The value of x in the composition formula can be controlled by changing the mixing ratio of the starting materials.

[0049] Next, the metal titanate powder is suspended in an aqueous solvent, and then an acid solution is added to extract the metal ions (the metal ions in the metal titanate are ion-exchanged with the cations in the acid), thereby producing layered titanic acid. The aqueous acid solution can be an inorganic acid such as hydrochloric acid or sulfuric acid, or an organic acid such as acetic acid or oxalic acid.

[0050] The layered titanic acid is a compound in which metal ions between layers are replaced with hydrogen ions and Ti in the host skeleton is 4+ Formula H with some substitution of the sites 4x / 3 Ti 2-x / 3 A compound having an orthorhombic layer structure represented by the formula O4·nH2O (wherein x is 0.50 to 1.0 and n is 0 to 2) is preferred. It is not necessary for all metal ions to be replaced with hydrogen ions, and some metal ions may remain as long as the effects of the present invention are achieved.

[0051] Next, the layered titanic acid is mixed with an aqueous solution (a solution mainly composed of water) to prepare a slurry, and a water-soluble basic organic compound is then mixed with this. In the present invention, "water-soluble" means that 10 g or more of the basic organic compound dissolves in 100 g of water. Through this process, the basic organic compound is inserted between the layers through an exchange reaction between the hydrogen ions contained in the layered titanic acid and the basic organic compound, swelling and / or peeling off at least some of the layers to obtain plate-like titanic acid particles.

[0052] There are no particular limitations on the water-soluble basic organic compound, and one or more of any basic organic compounds can be appropriately selected and used. Examples include (1) quaternary ammonium hydroxide compounds (tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, etc.), (2) amine compounds having an alkyl group having 5 or less carbon atoms (propylamine, diethylamine, etc.), and (3) alkanolamine compounds (ethanolamine, aminomethylpropanol, etc.). Among these, alkanolamine compounds are preferred, and aminomethylpropanol is more preferred.

[0053] The degree of exfoliation of the layered titanic acid can be controlled by appropriately setting conditions such as the type and amount of the basic organic compound used, the concentration of the layered titanic acid slurry, the temperature and pH of the slurry when the two are brought into contact, the mixing speed and time, etc. This allows the thickness of the obtained plate-like titanic acid particles to be controlled to a desired thickness.

[0054] The slurry thus obtained in which the plate-like titanic acid particles are dispersed (i.e., plate-like titanic acid slurry) can be subjected to solid-liquid separation by a known method, and further washed and dried as necessary. For example, the plate-like titanic acid slurry can be centrifuged to separate the precipitate and the solution, and then dried to obtain a solid content. Alternatively, the plate-like titanic acid slurry can be spray-dried to obtain a solid content. Furthermore, a solid content can be obtained by combining several known methods for separating and washing solid content.

[0055] The obtained solid content can be pulverized as needed. The above-mentioned known pulverizers can be used for pulverization. From the viewpoint of maintaining the shape of the plate-like titanate particles (the dimensions and size of the flake surfaces), equipment with a weak pulverizing force is preferred. Examples of such pulverizers include a hammer mill and a pin mill.

[0056] (Hydrous alumina treatment) Aluminum hydroxide (hydrated alumina) is made to exist on the surface of plate-like titanic acid particles. This treatment can be carried out in an aqueous solution. For example, a slurry in which plate-like titanic acid particles are dispersed in an aqueous solution (i.e., a plate-like titanic acid aqueous slurry) is prepared, and an aluminum compound (aluminum source) is added as a raw material to this slurry. The pH of the slurry is further adjusted to precipitate aluminum hydroxide (hydrated alumina) from the aluminum source, which can be made to exist on the surface of the plate-like titanic acid particles.

[0057] The aluminum source used as the raw material can be one that precipitates aluminum hydroxide (hydrated alumina) upon neutralization, such as sodium aluminate or aluminum sulfate. The amount of the aluminum source added is preferably 1% by mass or more and 30% by mass or less, more preferably 3% by mass or more and 25% by mass or less, and even more preferably 5% by mass or more and 20% by mass or less, calculated as Al2O3.

[0058] The pH of the aqueous slurry when the aluminum source is neutralized is preferably in the range of 5 to 12, more preferably 6 to 9. Various acids and bases can be used to adjust the pH of the slurry. For example, when sodium aluminate is used as the aluminum source, sulfuric acid or hydrochloric acid can be used. When aluminum sulfate is used as the aluminum source, sodium hydroxide or aqueous ammonia can be used.

[0059] When neutralizing the aluminum source, the order of adding the aluminum source and the acid or base is not particularly limited. For example, an aluminum compound may be added to the aqueous plate-like titanic acid slurry in advance, and then the acid or base may be added thereto to adjust the pH of the slurry. Alternatively, the aluminum source and the acid or base may be added simultaneously to the plate-like titanic acid slurry while maintaining the pH of the slurry at a predetermined value.

[0060] The temperature of the slurry during neutralization of the aluminum source is preferably maintained between 50°C and 95°C, and more preferably between 70°C and 90°C. Maintaining the temperature within this range allows aluminum hydroxide (hydrated alumina) to be more densely coated on the surface of the plate-like titanic acid particles. This is preferable because the anionic surfactant is more easily adsorbed onto the surface of the plate-like titanic acid particles after the subsequent anionic surfactant treatment. The temperature of the slurry is preferably raised to the above-mentioned predetermined temperature before starting the neutralization of the aluminum source. After the neutralization of the aluminum source is complete, the slurry may be left (aged) for several minutes to several hours while maintaining the above-mentioned predetermined temperature.

[0061] The slurry after the above treatment is subjected to solid-liquid separation by a known method as needed, and further dried and calcined as needed. Spray drying can be used as a method for simultaneously performing solid-liquid separation and drying. Depending on the drying and calcination temperatures, aluminum hydroxide (hydrated alumina) changes to aluminum oxide (alumina). For example, when the drying temperature is set to about 200°C, part of the aluminum hydroxide (hydrated alumina) changes to oxide (alumina), resulting in a mixture of aluminum oxide and hydroxide. Furthermore, when calcined at a higher temperature (for example, 300°C or higher), most of the aluminum hydroxide (hydrated alumina) changes to oxide (alumina).

[0062] (Treatment with anionic surfactant) Plate-like titanate particles treated with aluminum oxide and / or hydroxide are treated with the anionic surfactant. This treatment can also be carried out in solution. For example, the plate-like titanate having the aluminum oxide and / or hydroxide on its surface (i.e., the aluminum oxide and / or hydroxide present on the particle surface) is mixed with an anionic surfactant in solution. Preferably, the plate-like titanate having the aluminum oxide and / or hydroxide on its surface is mixed with a hydrocarbon-based anionic surfactant having 5 or more carbon atoms in its main chain and / or a fluorine-based anionic surfactant having 4 or more carbon atoms in its main chain in solution. An anionic surfactant may be added to the plate-like titanate slurry (i.e., a slurry in which plate-like titanate particles whose particle surfaces have been treated with aluminum oxide and / or hydroxide are dispersed) and mixed for a predetermined period of time. Alternatively, the plate-like titanate particles or plate-like titanate slurry may be added to a solution of an anionic surfactant and mixed for a predetermined period of time to form a slurry. Water or a mixture of water and an organic solvent can be used as the solvent. Some anionic surfactants do not dissolve easily in water. In such cases, a mixed solution of water and an organic solvent such as ethanol can be used as the solvent.

[0063] As described above, the hydrocarbon-based anionic surfactant used in this treatment may be a carboxylic acid type, sulfonic acid type, sulfate ester type, phosphate ester type, etc., and the fluorine-based anionic surfactant may be a carboxylic acid type, sulfonic acid type, phosphate ester type, etc. The amount of the anionic surfactant added is preferably 0.01% by mass or more and 30% by mass or less, more preferably 0.5% by mass or more and 30% by mass or less, and even more preferably 5% by mass or more and 25% by mass or less, based on the plate-like titanic acid.

[0064] The temperature of the slurry when treated with an anionic surfactant may be room temperature (10 to 30°C), the same temperature as that used in the hydrous alumina treatment, or heated (30 to 95°C). Whether at room temperature or heated, the anionic surfactant can be sufficiently adsorbed onto or reacted with the surface of the plate-like titanic acid particles treated with aluminum oxide and / or hydroxide. The mixing time of the slurry can be appropriately set within a range of several minutes to several hours.

[0065] The plate-like titanate particles, the particle surfaces of which have been treated with aluminum oxide and / or hydroxide and further treated with an anionic surfactant as described above, may be centrifuged or subjected to solid-liquid separation, and may be washed, dried, or otherwise processed as needed by known methods, to obtain the coated plate-like titanate particles of the present invention. [Example]

[0066] The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to these examples.

[0067] (Production of plate-shaped titanic acid particles) The plate-like titanic acid particles used in the examples and comparative examples were produced as follows.

[0068] (Production Example 1) Titanium oxide (Ishihara Sangyo Kaisha, Ltd. Titanium oxide A-100), potassium carbonate, and lithium carbonate (both reagents manufactured by Kanto Chemical Co., Ltd.) were thoroughly mixed in an agate mortar in a mass ratio of 100:40:9.2, and then fired in air at 1150°C for 5 hours to produce potassium lithium titanate (K) with an orthorhombic lepidocrocite structure. 0.8 Li 0.27 Ti 1.73 O4) was synthesized. The obtained lithium potassium titanate was crushed in an agate mortar to obtain lithium potassium titanate powder.

[0069] The obtained lithium potassium titanate powder was mixed with four times the mass of 1.1 N sulfuric acid aqueous solution and stirred for 30 minutes to carry out ion exchange, thereby obtaining a layered titanic acid solid. The obtained layered titanic acid solid was filtered and washed to obtain a layered titanic acid cake.

[0070] The obtained layered titanic acid cake was dispersed again in pure water to a concentration of 8.5 mass % in terms of TiO2 to obtain a layered titanic acid dispersion. The layered titanic acid dispersion was mixed with ammonia water to adjust the pH to 8.7, and then 21.4 g of a 90 mass % aqueous solution of 2-amino-2-methyl-1-propanol (0.3 neutralization equivalents to the hydrogen ions contained in the layered titanic acid) was added per 100 g of TiO2, and the mixture was stirred at room temperature for 1 hour to obtain a plate-like titanic acid dispersion.

[0071] A mesh with 10 μm openings was attached to a slurry cleaner (SS95×250 manufactured by Accor Japan Co., Ltd.), and a solution obtained by diluting the obtained plate-like titanic acid dispersion two-fold with pure water was passed through it at a rate of 18 L / hour, and the plate-like titanic acid dispersion on the mesh was collected.

[0072] The plate-like titanic acid dispersion on the mesh was diluted three times and centrifuged using a centrifuge (SJ10F, manufactured by Mitsubishi Chemical Engineering Co., Ltd.) The resulting precipitate (plate-like titanic acid cake) was spray-dried using a spray dryer (L-8i, manufactured by Okawara Chemical Engineering Co., Ltd.) under conditions of an inlet temperature of 190°C and an outlet temperature of 85°C, to obtain plate-like titanic acid powder A as plate-like titanic acid particles.

[0073] The particle size of this plate-like titanic acid powder A was measured, and the median diameter (D50) in the volume particle size distribution was 20.4 μm, the cumulative 10% particle diameter (D10) was 10.1 μm, and the cumulative 90% particle diameter (D90) was 39.1 μm. The measurement conditions were as follows: Measurement equipment: Laser diffraction / scattering particle size distribution measurement equipment (HORIBA, Ltd., LA-950) Refractive index: 2.50

[0074] Example 1 (1) Hydrous alumina treatment The plate-like titanic acid powder A from the above Production Example was dispersed in pure water to a solids content of 10% by mass to form a slurry, and the temperature of the slurry was raised to 90°C. Next, the pH of the slurry was adjusted to 7.0 with sulfuric acid (4.6 normal). After that, a sodium aluminate aqueous solution equivalent to 10% by mass of Al2O3 relative to the plate-like titanic acid and sulfuric acid (1.1 normal) were simultaneously added so that the pH of the slurry was maintained at 7.0 to 7.5 to neutralize the sodium aluminate. The slurry was further aged for 1 hour to treat the plate-like titanic acid with hydrous alumina (aluminum hydroxide). This slurry was centrifuged at 10,000 rpm for 10 minutes to obtain plate-like titanic acid cake B.

[0075] (2) Treatment of anionic surfactants Lauryl phosphoric acid (20% by mass relative to the plate-like titanic acid) was dissolved in a 5:3 mixture of pure water and ethanol by mass, and plate-like titanic acid cake B was mixed with this solution at room temperature to a solids content of 15% by mass to prepare a slurry. After stirring for 30 minutes, the slurry was centrifuged at 10,000 rpm for 10 minutes to obtain plate-like titanic acid cake C. Next, pure water was added to plate-like titanic acid cake C to prepare a slurry with a solids content of 5% by mass. The slurry was spray-dried using a spray dryer (L-8i manufactured by Okawara Kakoki Co., Ltd.) under conditions of an inlet temperature of 190°C and an outlet temperature of 85°C, to obtain a powder of coated plate-like titanic acid particles of Example 1.

[0076] (Examples 2 and 3) The powder of coated plate-like titanate particles of Example 2 and the powder of coated plate-like titanate particles of Example 3 were obtained in the same manner as Example 1, except that in the alumina treatment step (1) of Example 1, the amount of sodium aluminate aqueous solution added was 3 mass% or 6 mass% in terms of Al2O3.

[0077] (Examples 4 and 5) Powders of coated plate-like titanate particles of Example 4 and powders of coated plate-like titanate particles of Example 5 were obtained in the same manner as Example 1, except that in the anionic surfactant treatment step (2) of Example 1, the amount of lauryl phosphate added was 5% by mass and 10% by mass relative to the plate-like titanate.

[0078] Example 6 The powder of coated plate-like titanate particles of Example 6 was obtained in the same manner as Example 1, except that in the alumina treatment step (1) of Example 1, the temperature of the slurry was raised to 60°C instead of 90°C.

[0079] (Examples 7 to 9) Powders of coated plate-like titanic acid particles of Examples 7 to 9 were obtained in the same manner as in Example 1, except that in the anionic surfactant treatment step (2) of Example 1, 10 mass% of 2-ethylhexyl acid phosphate (JP-508 manufactured by Johoku Chemical Industry Co., Ltd.), alkyl (C12, C14, C16, C18) acid phosphate (JP-512 manufactured by Johoku Chemical Industry Co., Ltd.), or isotridecyl acid phosphate (JP-513 manufactured by Johoku Chemical Industry Co., Ltd.) was added relative to the plate-like titanic acid instead of lauryl phosphoric acid.

[0080] Example 10 In the anionic surfactant treatment step (2) of Example 1, instead of lauryl phosphate, 20% by mass of sodium lauryl phosphate relative to the plate-like titanic acid was dissolved in pure water, and plate-like titanic acid cake B was mixed with the purified water to obtain a slurry with a solid content of 15% by mass. After stirring for 30 minutes, the slurry was centrifuged at 10,000 rpm for 10 minutes to obtain plate-like titanic acid cake D. Next, pure water was added to plate-like titanic acid cake D to prepare a slurry with a solid content of 8% by mass. The slurry was spray-dried using a spray dryer (L-8i manufactured by Okawara Kakoki Co., Ltd.) under conditions of an inlet temperature of 190°C and an outlet temperature of 85°C, to obtain a powder of coated plate-like titanic acid particles of Example 10.

[0081] (Examples 11 to 15) Powders of coated plate-like titanic acid particles of Examples 11 to 15 were obtained in the same manner as in Example 10, except that in the anionic surfactant treatment step (2) of Example 10, instead of sodium lauryl phosphate, 10 mass% of sodium laurate, sodium lauryl sulfate, polyoxyethylene alkyl (12-15) ether phosphate (Phosphanol (registered trademark) RS-710, manufactured by Toho Chemical Industry Co., Ltd.), polyoxyethylene lauryl ether phosphate (Phosphanol (registered trademark) RD-510Y, manufactured by Toho Chemical Industry Co., Ltd.), or polyoxyethylene lauryl ether phosphate (Phosphanol (registered trademark) RB-410, manufactured by Toho Chemical Industry Co., Ltd.) was added, relative to the plate-like titanic acid.

[0082] (Examples 16 to 18) Powders of coated plate-like titanic acid particles of Examples 16 to 18 were obtained in the same manner as Example 1, except that in the anionic surfactant treatment step (2) of Example 1, instead of lauryl phosphate, 5 mass% of a perfluoroalkyl acid salt (Surflon (registered trademark) S-211 manufactured by AGC Seimi Chemical Co., Ltd.), perfluorobutyl sulfonic acid, and a perfluoroalkyl phosphate ester (FPE-50 manufactured by AGC Seimi Chemical Co., Ltd.) were added relative to the plate-like titanic acid.

[0083] Example 19 The powder of coated plate-like titanic acid particles of Example 19 was obtained in the same manner as Example 1, except that in the anionic surfactant treatment step (2) of Example 1, 0.05 mass% of perfluoroalkyl phosphate ester was added relative to the plate-like titanic acid instead of lauryl phosphate.

[0084] (Comparative Example 1) Untreated plate-like titanic acid powder A that had not undergone the above-mentioned "(1) hydrous alumina treatment" step and "(2) anionic surfactant treatment" step was used as a sample of Comparative Example 1.

[0085] (Comparative Example 2) Pure water was added to the plate-like titanic acid cake B to prepare a slurry with a solid content of 8% by mass. The slurry was spray-dried using a spray dryer (L-8i, manufactured by Okawara Kakoki Co., Ltd.) under conditions of an inlet temperature of 190°C and an outlet temperature of 85°C. This resulted in a sample of Comparative Example 2 in which the particle surfaces of the plate-like titanic acid were treated with hydrous alumina (aluminum hydroxide) (i.e., the above-mentioned "(2) anionic surfactant treatment" step was not performed).

[0086] (Comparative Example 3) Lauryl phosphoric acid (20% by mass relative to the amount of plate-like titanic acid) was dissolved in a 5:3 mixture of pure water and ethanol, and plate-like titanic acid powder A was mixed therewith to a solid content of 15% by mass. After stirring for 30 minutes, the mixture was centrifuged at 10,000 rpm for 10 minutes to obtain plate-like titanic acid cake E. Pure water was then added to plate-like titanic acid cake E to prepare a slurry with a solid content of 8% by mass. This slurry was spray-dried using a spray dryer (L-8i, manufactured by Okawara Kakoki Co., Ltd.) under conditions of an inlet temperature of 190°C and an outlet temperature of 85°C. This resulted in a sample of Comparative Example 3 in which the particle surfaces of untreated plate-like titanic acid (i.e., not subjected to the above-mentioned "(1) hydrous alumina treatment" step) were treated with lauryl phosphoric acid.

[0087] Comparative Example 4 A sample of Comparative Example 4 was obtained in the same manner as in Example 10, except that 20% by mass of tetrabutylphosphonium (cationic surfactant) was added instead of sodium lauryl phosphate in the anionic surfactant treatment step (2) of Example 10.

[0088] (Comparative Example 5) 0.05 g of n-octylamine was dissolved in 0.3 g of a butyl acetate / xylene (1:1 mass ratio) mixed solution, and 0.50 g of plate-like titanic acid powder A was added and mixed to obtain an organic solvent dispersion of plate-like titanic acid particles, which was the sample of Comparative Example 5.

[0089] [Table 1]

[0090] (Preparation of coating film for evaluation) The powder of coated platelet titanate particles from Examples 1 to 19 or the samples from Comparative Examples 1 to 5 were placed in a 20 ml screw tube bottle as a pigment, and 6.9 g of an acrylic resin paint (manufactured by Nippon Paint Co., Ltd., nax® Admira® Alpha 280 corrective clear and 901 binder in a mass ratio of 3.6:1) was added to adjust the pigment mass / resin nonvolatile mass (P / B) to 0.25. The mixture was mixed for 5 minutes in a paint shaker to prepare a paint. The prepared paint was applied to a PET film (manufactured by Toray Industries, Inc., Lumirror® T60) using an 8 mil doctor blade and forced dried at 60°C for 30 minutes to prepare the evaluation coatings for Examples 1 to 19 and Comparative Examples 1 to 5.

[0091] (Evaluation of silky feeling (dense feeling, granular feeling)) The silkiness of the produced coating films was evaluated visually. Two indicators of silkiness were used: denseness and granularity. Denseness refers to a seamless, smooth design like silk, and was evaluated on a three-point scale from 1 to 3, with the densest being the most dense. Granularity refers to a design in which each particle appears to shine and sparkle individually, and was evaluated on a three-point scale from 1 to 3, with 1 being no granularity and 3 being a strong sparkle. Therefore, a score of 1 for both denseness and granularity indicates the highest silkiness. The evaluation results are shown in Table 2. It was confirmed that all of Examples 1 to 19 exhibited the highest silkiness.

[0092] [Table 2]

[0093] (Evaluation of shadow effect) A white black and white chart paper was placed on the back of the prepared coating film, and a multi-angle colorimeter (BYK BYK-mac (registered trademark) i) was used to irradiate the light source from a direction of -45°, and the lightness (L * The average L value was calculated from the three measurements.* Search for highlight L * 15° From Shade L * 110° Subtract ΔL * The results of the evaluation are shown in Table 3.

[0094] (Evaluation of yellowing resistance) The prepared coating film was irradiated with 3mW / cm 2 using a black light fluorescent lamp (FL20SBLB, manufactured by Panasonic Corporation). 2 After that, a black light with a light intensity of 15° was applied to the back of the prepared coating film, and a light source was irradiated from a direction of -45° using a multi-angle colorimeter (BYK BYK-mac (registered trademark) i) to measure the chromaticity (b * ) values ​​were measured. The average b * 15° After irradiating the black light, * 15° b before black light irradiation * 15° Subtracting Δb * 15° was calculated. Also, Δb * 110° is the average of three measurements * 110° After irradiating the black light, * 110° b before black light irradiation * 110° The evaluation results are shown in Table 3.

[0095] [Table 3]

[0096] As shown in Table 3, the coated plate-like titanate particles of each Example were all treated with hydrous alumina (aluminum hydroxide) and further treated with an anionic surfactant having a hydrocarbon group with 5 or more carbon atoms in the main chain or a fluorine-based anionic surfactant having a fluoroalkyl chain with 4 or more carbon atoms. When a coating film was formed using the coated plate-like titanate particles of such Examples, ΔL * The value of ΔL in this test system is large (specifically, * The value of Δb is 40 or more, and it was confirmed that the image shows a sufficient sense of shadow even when visually inspected. * 15° and Δb * 110° The value of Δb * 15° and Δb * 110° The values ​​of both were 2 or less), and it was confirmed by visual inspection that yellowing of the coating film was suppressed.

[0097] Furthermore, when the results of Example 1 and Example 6 are compared, the higher the temperature during the hydrous alumina treatment, the shorter ΔL * This is believed to be because the high temperature during treatment causes the hydrous alumina to more densely cover the surface of the plate-like titanate, promoting the adsorption of the anionic surfactant, and thereby improving the dispersion stability of the coated plate-like titanate particles in the organic solvent-based paint.

[0098] In contrast, as shown in Table 3, when using untreated plate-like titanic acid (Comparative Example 1) that was not subjected to the above-mentioned "(1) hydrous alumina treatment" and "(2) anionic surfactant treatment", when using plate-like titanic acid that was only subjected to the hydrous alumina treatment (i.e., only the above-mentioned "(1) hydrous alumina treatment" was performed, and not the above-mentioned "(2) anionic surfactant treatment") (Comparative Example 2), or when using plate-like titanic acid that was only subjected to the treatment with an anionic surfactant having a linear hydrocarbon group with 12 carbon atoms (i.e., only the above-mentioned "(1) hydrous alumina treatment" was performed, and not the above-mentioned "(2) anionic surfactant treatment") (Comparative Example 3), yellowing of the coating film hardly occurred, but ΔL * The value of ΔL in this test system is small (specifically, * The value of was less than 40), and it was confirmed that the visual sense of shadow was insufficient. A similar tendency was observed even when using plate-like titanic acid that had been treated with another surfactant (cationic, with a linear chain containing four carbon atoms) in addition to the hydrous alumina treatment, as in Comparative Example 4. This is understood to be because the treatments in Comparative Examples 1 to 4 did not sufficiently hydrophobize the surface of the plate-like titanic acid particles, and therefore the dispersion stability of the plate-like titanic acid particles in the organic solvent-based paint could not be ensured.

[0099] In addition, as in Comparative Example 5, when an organic solvent dispersion containing plate-like titanic acid and an amine compound having a long-chain hydrocarbon group was used, ΔL * Although the value of Δb is large and the visual sense of shadow is sufficient, * 15° and Δb * 110° The values ​​of both were large, and yellowing of the coating film was confirmed visually. This is understood to be due to the amine compound contained in the organic solvent dispersion causing the yellowing of the coating film.

[0100] (Preparation of paint for adhesion evaluation) A 225 ml mayonnaise bottle was charged with 3 g of each of the coated platelet titanate particle powders from Examples 16 to 19 as pigments, and 33.4 g of acrylic resin paint (Nippon Paint Co., Ltd., nax® Admira® Alpha 280 Correction Clear and 901 Binder, mass ratio 3.6:1) was added to achieve a pigment mass / resin nonvolatile mass (P / B) ratio of 0.25. After mixing for 5 minutes with a paint shaker, the paint viscosity was adjusted to 10 seconds using a viscosity cup (ANEST IWATA Corporation, NK-2 Cup) with thinner (Nippon Paint Co., Ltd., nax® Admira® Alpha 500 Standard Thinner). A curing agent (Nippon Paint Co., Ltd., nax® Ultra Hardener) was added to prepare a paint for adhesion evaluation.

[0101] (Preparation of coating film for adhesion evaluation) The surface of a 35mm x 150mm x 0.8mm steel plate was sanded with sandpaper (#400), and then an acrylic urethane resin paint (manufactured by Nippon Paint Co., Ltd., nax (registered trademark) Urethane Primer Pro V1 White, nax (registered trademark) #20 Ultra Hardener Standard, nax (registered trademark) Multi #20 Standard Urethane Thinner NEO (2 stones) in a mass ratio of 10:1.5:3) was applied with an Anest Iwata Corporation spray gun (KIWAMI-1-14KP6) under conditions of 0.15MPa hand pressure, 2.0 rotations of discharge rate, full air volume, and full pattern width, so that the coating thickness was 50μm. After setting for 10 minutes or more, the plate was forced to dry at 60 ° C for 40 minutes and then sanded with sandpaper (#400). Next, the above-mentioned paint for adhesion evaluation was applied to a spray gun (W-101-138BGC) manufactured by Anest Iwata Corporation under the conditions of a hand pressure of 0.15 MPa, a discharge rate of 1.5 revolutions, an air volume fully open, and a pattern width fully open, so that the coating film thickness was 30 μm, and after setting for 30 minutes or more, it was forced dried at 60 ° C. for 30 minutes. To this, a clear paint (manufactured by Kansai Paint Co., Ltd., Retan (registered trademark) PG80III026 clear, Retan (registered trademark) PG80III026 clear hardener, Retan (registered trademark) PG thinner standard type in a mass ratio of 10:1:4) was applied to a spray gun (KIWAMI-1-14KP6) manufactured by Anest Iwata Corporation under the conditions of a hand pressure of 0.15 MPa, a discharge rate of 2.0 revolutions, an air volume fully open, and a pattern width fully open, so that the coating film thickness was 40 μm. After setting for 30 minutes or more, the coating was forced dried at 60°C for 12 hours to prepare a coating film for adhesion evaluation.

[0102] (Evaluation of Adhesion) The adhesion of the coating was evaluated using a cross-cut test. A cutter knife was placed perpendicularly on the coating surface for adhesion evaluation, and 11 equally spaced parallel lines were drawn down to the substrate. Eleven equally spaced parallel lines were then drawn intersecting these parallel lines, resulting in 100 squares surrounded by four straight lines. The parallel lines were spaced 2 mm apart. Adhesive tape (Nichiban Cellotape (registered trademark) L Pack 24, manufactured by Nichiban Co., Ltd.) was evenly pressed onto the surface of the test piece where the cross-cuts had been made, ensuring no air bubbles were present. Holding one end of the adhesive tape, the tape was peeled off the test piece at a 45° angle from the vertical plane of the coating. The number of squares within a 2 mm square where the coating had peeled off by 50% or less was counted to evaluate initial adhesion. A higher initial adhesion value indicates better adhesion. Next, pure water was placed in a thermostatic water bath and maintained at 40°C, with at least half of the coated steel sheet submerged in water. After 168 hours of immersion, the sheet was removed from the bath, and any water droplets or contaminants were wiped off with a cloth. The sheet was then left for 12 hours, after which the cross-cut test was carried out in the same manner. The results are shown in Table 4.

[0103] [Table 4]

[0104] As shown in Table 4, it was confirmed that the coating film formed using coated plate-like titanate particles treated with hydrous alumina (aluminum hydroxide) and a fluorine-based anionic surfactant with a main chain of four or more carbon atoms exhibits high initial adhesion and water-resistant adhesion to the substrate.

[0105] From the above, it can be seen that the coated plate-like titanate particles of this example are treated with hydrous alumina (aluminum hydroxide) and further treated with an anionic surfactant having a main chain carbon number of 5 or more, or a fluorine-based anionic surfactant having a fluoroalkyl chain having a carbon number of 4 or more, and therefore, in organic solvent-based paints using these, it is possible to achieve both a sufficient silky feel and shading effect as well as excellent yellowing resistance. In particular, coated plate-like titanate particles treated with a fluorine-based anionic surfactant having a fluoroalkyl chain with four or more carbon atoms can ensure adhesion to the substrate and water resistance when used to form a coating film. [Industrial Applicability]

[0106] According to the present invention, plate-like titanic acid can be applied to organic solvent-based paints, and decorative coating films with both a silky feel and a good sense of shading can be realized. Moreover, discoloration (yellowing) of the coating film is sufficiently suppressed even when placed in a relatively severe environment, such as long-term exposure to ultraviolet light. Therefore, by blending the coated plate-like titanic acid particles of the present invention, particularly in organic solvent-based paints, it is possible to provide practical articles with unique designs that have never been seen before.

Claims

1. Coated plate-like titanic acid particles, in which aluminum oxide and / or hydroxide and an anionic surfactant are present on the surface of the plate-like titanic acid particles.

2. The coated plate-like titanate particles according to claim 1, wherein the anionic surfactant is a hydrocarbon-based anionic surfactant having a main chain carbon number of 5 or more and / or a fluorine-based anionic surfactant having a main chain carbon number of 4 or more.

3. 3. The coated plate-like titanate particles according to claim 1, wherein the anionic surfactant is present on the aluminum oxide and / or hydroxide on the surface of the plate-like titanate particles.

4. 4. The coated plate-like titanate particles according to claim 1, wherein the content of the anionic surfactant is 0.01% by mass or more and 30% by mass or less based on the mass of the plate-like titanate.

5. The content of the aluminum oxide and / or hydroxide relative to the plate-like titanate is ２ O ３ The coated plate-like titanate particles according to any one of claims 1 to 4, wherein the content of the coated plate-like titanate particles is 1% by mass or more and 30% by mass or less in terms of the total mass of the coated plate-like titanate particles.

6. A decorative pigment comprising the coated plate-like titanate particles according to any one of claims 1 to 5.

7. 6. An organic solvent dispersion comprising the coated plate-like titanate particles according to claim 1 and an organic solvent.

8. A coating composition comprising the coated plate-like titanate particles according to any one of claims 1 to 5 and a resin component.

9. A plastic composition comprising the coated plate-like titanate particles according to any one of claims 1 to 5 and a resin component.

10. A method for producing coated plate-like titanic acid particles, comprising the step of mixing, in a solution, plate-like titanic acid having aluminum oxide and / or hydroxide present on the particle surface with an anionic surfactant.

11. The method for producing coated plate-like titanate particles according to claim 10, wherein the anionic surfactant is a hydrocarbon-based anionic surfactant having a main chain carbon number of 5 or more and / or a fluorine-based anionic surfactant having a main chain carbon number of 4 or more.

12. 12. The method for producing coated plate-like titanate particles according to claim 10 or 11, comprising a step of causing the aluminum oxide and / or hydroxide to be present on the surface of plate-like titanate particles, the step comprising maintaining the temperature of an aqueous slurry containing the plate-like titanate particles and an aluminum source at 50°C or higher and 95°C or lower, and maintaining the pH of the aqueous slurry at 5 or higher and 12 or lower.

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