2-component mixed paint composition

Abstract

To provide a two liquid mixed coating composition that has a sufficient service time, is less in variation of finishing appearance during the service time, and is provided also with water resistance.SOLUTION: A two-liquid mixed type coating composition in which a main agent and a curing agent are mixed before coating has the main agent containing a hydroxyl group-containing acrylic resin (A), a pigment component (B) and an oxime compound (C) and a curing agent containing a polyisocyanate compound (D), in which the hydroxyl group-containing acrylic resin (A) has a carboxyl group, and an amount of the oxime compound (C) is 0.1 to 10 pts.mass based on 100 pts.mass of a nonvolatile content of the resin component contained in the main agent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a two-component coating composition. [Background technology]

[0002] Two-component urethane resin paints, which use a hydroxyl-containing resin and a polyisocyanate compound, are typically packaged in two separate paint cans. One can contains the base agent, which contains the hydroxyl-containing resin, and the other contains the hardener, which contains the polyisocyanate compound. Painters then remove the contents of the base agent and hardener cans, measure and mix them, and use the resulting mixture as paint. The coating film formed from paint prepared in this way has excellent elasticity and flexibility, meeting market needs, and so two-component urethane resin paints are widely used in the paint industry.

[0003] However, because the chemical reaction between the hydroxyl-containing resin and polyisocyanate begins as soon as the paint contractor mixes the base resin and curing agent, leaving too much time between mixing and painting can significantly increase the viscosity of the mixture or cause gelation, resulting in a deterioration in the quality of the paint film. To prevent these problems, paint manufacturers set a pot life, the time the base resin and curing agent can be used after mixing, and impose usage limits on paint contractors. As a result, paint contractors must complete painting work within the set pot life, which requires them to complete the work as quickly as possible after mixing the base resin and curing agent at the painting site and to manage the amount of paint used.

[0004] Many attempts have been made to extend the usable life of two-component urethane resin coatings. For example, Patent Document 1 discloses a multi-component organic solvent-based urethane-curing coating resin composition that contains a sulfur-containing organotin catalyst in either or both of a base component containing an acrylic polyol or a curing agent component containing a polyisocyanate compound.

[0005] Furthermore, Patent Document 2 discloses a high solids coating composition containing a secondary hydroxyl group-containing acrylic resin as a base resin, a combination of an aliphatic polyisocyanate compound and an alkyl-etherified melamine resin as a crosslinking agent, and a sulfonic acid compound and / or a phosphoric acid compound. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-152215 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-165955 Summary of the Invention [Problem to be solved by the invention]

[0007] Thus, in order to extend the usable life of two-component urethane paints, methods have been adopted such as using specific curing catalysts or resins containing mildly reactive secondary hydroxyl groups. However, even if these methods can extend the usable life, when painting large areas such as the exterior walls of buildings, there is a problem in that there will be a difference in gloss between areas painted immediately after mixing and areas painted some time after mixing, resulting in a poor appearance.

[0008] An object of the present invention is to provide a two-component mixed coating composition which has a sufficient pot life, undergoes little change in finished appearance during the pot life, and also has water resistance. [Means for solving the problem]

[0009] The present inventors have conducted extensive research into the above-mentioned problems, and as a result have found that, in a two-component coating composition, adding a specific amount of an oxime compound to a specific hydroxyl group-containing acrylic resin not only enables the rate of viscosity increase after mixing with a polyisocyanate compound to be moderately adjusted, but also results in a coating film that exhibits little change in appearance even over time after mixing the two components.

[0010] That is, the present invention is characterized by the following items 1 to 9. Item 1. A two-component mixed coating composition in which the base agent and the curing agent are mixed before painting, The composition comprises a base material containing a hydroxyl group-containing acrylic resin (A), a pigment component (B), and an oxime compound (C), and a curing agent containing a polyisocyanate compound (D), the hydroxyl group-containing acrylic resin (A) has a carboxyl group, A two-component mixed coating composition, wherein the amount of the oxime compound (C) is within the range of 0.1 to 10 parts by mass based on 100 parts by mass of the nonvolatile content of the resin component contained in the main agent. Item 2. The two-component coating composition according to Item 1, wherein the amount of the carboxyl group-containing polymerizable unsaturated monomer is 0.1 to 10 parts by mass per 100 parts by mass of all polymerizable unsaturated monomer components used in producing the hydroxyl group-containing acrylic resin (A). Item 3. The two-component coating composition according to Item 1 or 2, wherein the pigment component (B) contains at least one type of inorganic particle (b) selected from barium sulfate, calcium carbonate, and silica. Item 4. The two-component coating composition according to Item 3, wherein the inorganic particles (b) have an average particle size within the range of 0.1 to 10 μm. Item 5. The two-component coating composition according to any one of Items 1 to 4, further comprising an amino group-containing acrylic resin (E). Item 6. The two-component coating composition according to any one of Items 1 to 5, further comprising an antifoaming agent (F). Item 7. The two-component coating composition according to any one of Items 1 to 6, further comprising a weak solvent as the organic solvent (G). Item 8. A method for forming a coating film, comprising applying the two-component mixed coating composition according to any one of Items 1 to 7 to a substrate surface. Item 9. A method for forming a coating film, comprising applying an undercoat paint to a substrate surface and then applying the two-component mixed coating composition according to any one of Items 1 to 7 as a topcoat paint. Regarding. [Effects of the Invention]

[0011] The two-component mixed coating composition of the present invention shows a gradual increase in viscosity after mixing the base agent and curing agent, and there is no noticeable difference in appearance between an area painted immediately after mixing and an area painted after some time has passed. This allows for the consistent production of a coating film with a finished appearance that is minimal overall, and the resulting coating film has good physical properties such as water resistance. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the two-component mixed coating composition of the present invention will be described in detail. In this specification, (meth)acrylate means acrylate or methacrylate, and the same applies to (meth)acryloyl, (meth)acrylic, etc.

[0013] The two-component coating composition of the present invention comprises a base material containing a hydroxyl group-containing acrylic resin (A), a pigment component (B) and an oxime compound (C), and a curing agent containing a polyisocyanate compound (D), wherein the hydroxyl group-containing acrylic resin (A) has a carboxyl group, and the oxime compound (C) is contained in an amount of 0.1 to 10 parts by mass based on 100 parts by mass of the nonvolatile content of the resin components contained in the base material.

[0014] Hydroxyl-containing acrylic resin (A): In the present invention, the hydroxyl group-containing acrylic resin (A) refers to a resin having hydroxyl groups in the resin and containing a polymerizable unsaturated monomer component containing a (meth)acryloyl group-containing compound as a copolymerization component. Here, the hydroxyl group-containing acrylic resin (A) also includes modified resins modified with resins other than acrylic resins, such as alkyd resins. Furthermore, the hydroxyl group-containing acrylic resin (A) may be a single resin or a mixture of multiple resins.

[0015] The hydroxyl group-containing acrylic resin (A) preferably has a hydroxyl value in the range of 10 to 150 mgKOH / g, more preferably 30 to 100 mgKOH / g, and a weight average molecular weight in the range of 10,000 to 80,000, more preferably 20,000 to 60,000.

[0016] In this specification, the hydroxyl value means the amount of potassium hydroxide equivalent to the hydroxyl group in 1 g of sample in mg, and the weight average molecular weight is the value obtained by converting the weight average molecular weight measured by gel permeation chromatography based on the weight average molecular weight of polystyrene. Gel permeation chromatography is performed using, for example, an "HLC8120GPC" (manufactured by Tosoh Corporation). Four columns, for example, "TSKgel G-4000HXL," "TSKgel G-3000HXL," "TSKgel G-2500HXL," and "TSKgel G-2000HXL" (all manufactured by Tosoh Corporation, trade names), are used under the following conditions: mobile phase: tetrahydrofuran, measurement temperature: 40°C, flow rate: 1 cc / min, and detector: RI.

[0017] Specific examples of the hydroxyl group-containing polymerizable unsaturated monomer that serves as the hydroxyl group source for the hydroxyl group-containing acrylic resin (A) include monoesters of (meth)acrylic acid with dihydric alcohols having 2 to 8 carbon atoms, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; ε-caprolactone-modified monoesters of (meth)acrylic acid with dihydric alcohols having 2 to 8 carbon atoms; N-hydroxymethyl (meth)acrylamide; allyl alcohol; (meth)acrylates having a polyoxyethylene chain whose molecular terminal is a hydroxyl group; and combinations thereof.

[0018] Examples of other polymerizable unsaturated monomers that can be copolymerized with the hydroxyl group-containing polymerizable unsaturated monomer 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, pentyl (meth)acrylate, hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, and dodecyl (meth)acrylate. alkyl (meth)acrylates having an alkyl group such as alkyl or cycloalkyl (meth)acrylates, such as acrylate (lauryl (meth)acrylate), tridecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, cyclododecyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, and tricyclodecanyl (meth)acrylate; Aromatic ring-containing polymerizable unsaturated monomers such as benzyl (meth)acrylate, styrene, α-methylstyrene, and vinyltoluene; Polymerizable unsaturated monomers having an alkoxysilyl group, such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, γ-(meth)acryloyloxypropyltrimethoxysilane, and γ-(meth)acryloyloxypropyltriethoxysilane; Fatty acid-modified polymerizable unsaturated monomers obtained by addition reaction of drying oil fatty acids and / or semi-drying oil fatty acids with epoxy group-containing polymerizable unsaturated monomers: Polysiloxane-containing (meth)acrylate; Carboxyl group-containing polymerizable unsaturated monomers such as (meth)acrylic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate, and itaconic acid; nitrogen-containing polymerizable unsaturated monomers such as (meth)acrylonitrile and (meth)acrylamide; Epoxy group-containing polymerizable unsaturated monomers such as glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, 3,4-epoxycyclohexylethyl (meth)acrylate, 3,4-epoxycyclohexylpropyl (meth)acrylate, and allyl glycidyl ether; alkoxy group-containing polymerizable unsaturated monomers such as N-methoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, alkoxyalkyl(meth)acrylates such as methoxyethyl(meth)acrylate, methoxypropyl(meth)acrylate, ethoxyethyl(meth)acrylate, and ethoxypropyl(meth)acrylate, and polyalkylene glycol monoalkoxy(meth)acrylates such as polyethylene glycol monomethoxy(meth)acrylate; Examples include carbonyl group-containing polymerizable unsaturated monomers such as acrolein, diacetone acrylamide, diacetone methacrylamide, acetoacetoxyethyl methacrylate, formyl styrene, and vinyl alkyl ketones having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone). These may be used alone or in combination of two or more.

[0019] The other polymerizable unsaturated monomers preferably include linear, branched, or cyclic alkyl group-containing (meth)acrylates such as n-butyl (meth)acrylate, iso-butyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate.

[0020] The polymerizable unsaturated monomer component can be polymerized by solution polymerization, and the resulting resin may be either a random type or a block type.

[0021] The hydroxyl-containing acrylic resin (A) contains a carboxyl group from the viewpoints of workability over time after mixing the base resin and curing agent and the finished appearance. Specifically, the other polymerizable unsaturated monomer preferably includes a carboxyl-containing polymerizable unsaturated monomer. In this case, the copolymerization amount of the carboxyl-containing polymerizable unsaturated monomer is preferably within a range of 0.1 to 10 parts by mass, particularly preferably within a range of 0.3 to 5 parts by mass, per 100 parts by mass of all polymerizable unsaturated monomer components used in producing the hydroxyl-containing acrylic resin (A).

[0022] Furthermore, when the hydroxyl group-containing acrylic resin (A) is a hydroxyl group-containing alkyd-modified acrylic resin, examples of the hydroxyl group-containing alkyd-modified acrylic resin include resins having, as copolymerization components, an acid component containing a drying oil fatty acid and / or a semi-drying oil fatty acid and a polycarboxylic acid, a polyhydric alcohol component, and a polymerizable unsaturated monomer component containing a (meth)acryloyl group-containing compound.

[0023] The above-mentioned hydroxyl group-containing acrylic resin (A) is preferably contained in the range of 5 to 80 parts by mass, more preferably 10 to 70 parts by mass, per 100 parts by mass of the nonvolatile resin component contained in the base resin.

[0024] In this specification, the nonvolatile content refers to the residue remaining after removing volatile components such as water and organic solvents from a sample, and can be calculated by multiplying the mass of the sample by the nonvolatile content concentration. The nonvolatile content concentration can be determined by dividing the mass of the residue obtained by drying approximately 3 grams of a sample at 105°C for 3 hours by the mass before drying.

[0025] Pigment content (B): The pigment component (B) used in the coating composition of the present invention can be any conventionally known pigment, including, for example, white pigments such as titanium dioxide and zinc oxide; blue pigments such as cyanine blue and indanthrene blue; green pigments such as cyanine green and verdigris; organic red pigments such as azo and quinacridone, red pigments such as red iron oxide; organic yellow pigments such as benzimidazolone, isoindolinone, isoindoline, and quinophthalone, yellow pigments such as titanium yellow and yellow lead; black pigments such as carbon black, graphite, and pine soot; luster pigments such as aluminum powder, copper powder, nickel powder, titanium oxide-coated mica powder, iron oxide-coated mica powder, and lustrous graphite; and extender pigments such as talc, clay, silica, kaolin, barium sulfate, barium carbonate, calcium carbonate, and alumina white. These can be used alone or in combination depending on the desired coating color.

[0026] The amount of pigment component (B) used can be adjusted appropriately depending on the type of pigment, but generally, the mass of pigment component (B) is preferably in the range of 30 to 200 parts by mass, more preferably in the range of 50 to 150 parts by mass, based on 100 parts by mass of the non-volatile mass of the resin component contained in the main agent.

[0027] Furthermore, the pigment component (B) preferably contains at least one type of inorganic particle (b) selected from barium sulfate, calcium carbonate, and silica as part of its components. By including the inorganic particle (b) in the pigment component (B), a coating film with a matte, subdued appearance can be obtained.

[0028] In the present invention, the inorganic particles (b) preferably have an average particle size in the range of 0.1 to 10 μm, and more preferably in the range of 0.5 to 5.0 μm. By using inorganic particles within this average particle size range, a coating film can be obtained that exhibits little change in the finished appearance after mixing the base agent and curing agent.

[0029] In this specification, the average particle size of the inorganic particles (b) refers to the average particle size including not only the particle size of primary particles but also the particle size of secondary particles (aggregates), and is the D50 value of the volumetric particle size distribution. The D50 value is the particle size at which the cumulative particle size distribution from the small particle size side in the volumetric particle size distribution becomes 50%. Examples of measurement methods include a method using a laser diffraction scattering method in accordance with JIS Z 8825. Examples of measurement devices using the laser diffraction scattering method include the MicrotracMT3300EXII manufactured by Nikkiso Co., Ltd.

[0030] In this case, as a pretreatment, the sample is added to a mixed solvent of acetone and isopropyl alcohol and dispersed by applying ultrasonic waves for 1 minute, and the sample concentration is adjusted to a concentration that falls within the predetermined transmittance range set in the device (for example, 0.800 to 0.930).

[0031] When the coating composition of the present invention contains inorganic particles (b), the content of the inorganic particles (b) is preferably in the range of 1 to 30 parts by mass, more preferably in the range of 5 to 20 parts by mass, based on 100 parts by mass of the nonvolatile resin component contained in the main agent.

[0032] Oxime Compound (C): In the present invention, the base agent contains an oxime compound (C). By including the oxime compound (C) in the base agent, the oxime reacts appropriately with the isocyanate group, and the increase in viscosity after mixing with the curing agent containing the polyisocyanate compound (D) becomes gradual, thereby minimizing changes in the finished appearance over time after mixing the base agent and curing agent.

[0033] Specific examples of the oxime compound (C) include formamide oxime, acetamide oxime, acetoxime, diacetyl monooxime, benzophenone oxime, cyclohexanone oxime, methyl ethyl ketoxime (MEK oxime), methyl isobutyl ketoxime (MIBK oxime), dimethyl ketoxime, diethyl ketoxime; and combinations thereof.

[0034] The content of the oxime compound (C) is in the range of 0.1 to 10 parts by mass, preferably 0.5 to 8.0 parts by mass, based on 100 parts by mass of the nonvolatile resin components contained in the base resin, from the viewpoint of water resistance, etc. When the content of the oxime compound (C) is 0.1 part by mass or more based on 100 parts by mass of the nonvolatile resin components contained in the base resin, the effects of the present invention are obtained, and when it is 10 parts by mass or less, the viscosity increase after mixing the base resin and curing agent is gradual, suppressing changes in the finished appearance and maintaining water resistance of the coating film.

[0035] Polyisocyanate compound (D): In the present invention, the polyisocyanate compound (D) is a compound having two or more free isocyanate groups per molecule, and conventionally known compounds can be used without limitation. Examples include aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds, araliphatic polyisocyanate compounds, aromatic polyisocyanate compounds, and derivatives of these polyisocyanate compounds. Examples of derivatives of polyisocyanate compounds include dimers, trimers, biurets, allophanates, carbodiimides, uretdione, uretimine, isocyanurates, oxadiazinetrione, polymethylene polyphenyl polyisocyanates (crude MDI, polymeric MDI), and crude TDI. These polyisocyanate compounds and their derivatives may be used alone or in combination of two or more.

[0036] In the present invention, the amount of polyisocyanate compound (D) used is usually such that the equivalent ratio of NCO groups derived from polyisocyanate compound (D) to 1 equivalent of hydroxyl groups of the resin contained in the base resin (NCO / OH ratio) is within a range of 0.5 to 2.0, and more preferably within a range of 0.5 to 1.5.

[0037] Amino group-containing acrylic resin (E): In the present invention, the base agent preferably contains an amino group-containing acrylic resin (E). By containing the amino group-containing acrylic resin (E) in the base agent, the workability over time after mixing the base agent and the curing agent is improved. Examples of the amino group-containing acrylic resin (E) include resins containing amino group-containing polymerizable unsaturated monomers and other polymerizable unsaturated monomers as copolymerization components.

[0038] Examples of the amino group-containing polymerizable unsaturated monomer include N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, N-tert-butylaminoethyl (meth)acrylate, N,N-dimethylaminobutyl (meth)acrylate, and N,N-dimethylaminopropyl (meth)acrylamide.

[0039] Other polymerizable unsaturated monomers include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, dodecyl (meth)acrylate, lauryl (meth)acrylate, alkyl (meth)acrylates having an alkyl group such as alkyl or cycloalkyl (meth)acrylates, such as alkyl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, cyclododecyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, and tricyclodecanyl (meth)acrylate; hydroxyl group-containing polymerizable unsaturated monomers such as monoesters of (meth)acrylic acid with dihydric alcohols having 2 to 8 carbon atoms, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate, ε-caprolactone-modified products of the monoesters of (meth)acrylic acid with dihydric alcohols having 2 to 8 carbon atoms, N-hydroxymethyl (meth)acrylamide, allyl alcohol, and (meth)acrylates having a polyoxyethylene chain with a hydroxyl group at the molecular terminal; Aromatic ring-containing polymerizable unsaturated monomers such as benzyl (meth)acrylate, styrene, α-methylstyrene, and vinyltoluene; Nitrogen-containing polymerizable unsaturated monomers such as (meth)acrylonitrile and (meth)acrylamide ; alkoxy group-containing polymerizable unsaturated monomers such as N-methoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, alkoxyalkyl(meth)acrylates such as methoxyethyl(meth)acrylate, methoxypropyl(meth)acrylate, ethoxyethyl(meth)acrylate, and ethoxypropyl(meth)acrylate, and polyalkylene glycol monoalkoxy(meth)acrylates such as polyethylene glycol monomethoxy(meth)acrylate; Examples include carbonyl group-containing polymerizable unsaturated monomers such as acrolein, diacetone acrylamide, diacetone methacrylamide, acetoacetoxyethyl methacrylate, formyl styrene, and vinyl alkyl ketones having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone). These may be used alone or in combination of two or more.

[0040] The other polymerizable unsaturated monomer components for producing the amino group-containing acrylic resin (E) preferably include a linear, branched, or cyclic alkyl group-containing (meth)acrylate such as n-butyl(meth)acrylate, iso-butyl(meth)acrylate, tert-butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, n-octyl(meth)acrylate, lauryl(meth)acrylate, stearyl(meth)acrylate, cyclohexyl(meth)acrylate, or isobornyl(meth)acrylate.

[0041] In the amino group-containing acrylic resin (E), the copolymerization amount of the amino group-containing polymerizable unsaturated monomer is suitably within a range of 1 to 30 parts by mass, particularly preferably within a range of 2 to 25 parts by mass, based on 100 parts by mass of all polymerizable unsaturated monomers used in the production of the amino group-containing acrylic resin (E).

[0042] In producing the amino group-containing acrylic resin (E), the polymerizable unsaturated monomer components may be polymerized by solution polymerization, and the resulting resin may be either a random type or a block type.

[0043] The content of the amino group-containing acrylic resin (E) is preferably within a range of 5 to 50 parts by mass, more preferably within a range of 10 to 40 parts by mass, per 100 parts by mass of the nonvolatile content of the resin component contained in the base resin.

[0044] Antifoaming agent (F): The coating composition of the present invention preferably contains an antifoaming agent (F). Examples of the antifoaming agent (F) include silicone-based antifoaming agents and non-silicone-based antifoaming agents. Silicon-based antifoaming agents are antifoaming agents containing a surface-active polysiloxane or a modified product thereof, while non-silicone-based antifoaming agents are antifoaming agents that do not contain polysiloxane or a modified product thereof. Examples of silicone-based antifoaming agents include polysiloxane, fluorine-modified siloxane, amino-modified siloxane, alkyl-modified siloxane, polyether-modified siloxane, higher fatty acid-modified siloxane, carboxyl-modified siloxane, and alcohol-modified siloxane. Examples of non-silicone-based antifoaming agents include higher alcohol-based, higher alcohol derivative-based, fatty acid-based, fatty acid derivative-based, paraffin-based, (meth)acrylic polymer-based, and mineral oil-based. In particular, from the viewpoint of the finished appearance when applying with a roller, it is preferable that the antifoaming agent (F) be a fluorine-modified silicone-based antifoaming agent.

[0045] The content of the antifoaming agent (F) is preferably in the range of 0.05 to 5.0 parts by mass, more preferably in the range of 0.1 to 3.5 parts by mass, relative to 100 parts by mass of the resin component contained in the base resin.

[0046] Organic solvent (G): Preferred organic solvents (G) contained in the two-component mixed coating composition of the present invention include weak solvents.

[0047] The term "weak solvent" is commonly used in this field and generally refers to a solvent with weak dissolving power, but is not strictly defined. However, examples include those classified as Type 3 organic solvents in the classification of organic solvents under the Industrial Safety and Health Act.

[0048] Specific examples thereof include gasoline, kerosene, coal tar naphtha (including solvent naphtha), petroleum ether, petroleum naphtha, petroleum benzine, turpentine oil, and mineral spirits (including mineral thinner, petroleum spirits, white spirits, and mineral turpentine), which may be used alone or in combination of two or more.

[0049] In addition, the organic solvent (G) may contain organic solvents other than weak solvents, such as aliphatic solvents such as n-butane, n-hexane, n-heptane, n-octane, cyclopentane, cyclohexane, and cyclobutane; aromatic solvents such as toluene and xylene; ketone solvents such as methyl isobutyl ketone; ether solvents such as n-butyl ether and dioxane; ester solvents such as ethyl acetate, n-butyl acetate, isobutyl acetate, ethylene glycol monomethyl ether acetate, and butyl carbitol acetate; and ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and diisobutyl ketone.

[0050] Two-component paint composition: The coating composition of the present invention is a two-component coating composition containing the above-mentioned hydroxyl-containing acrylic resin (A), pigment (B), and oxime compound (C) as the base component, and a polyisocyanate compound (D) as the curing agent component. The base component and / or curing agent may optionally contain the amino-containing acrylic resin (E), antifoaming agent (F), and organic solvent (G). In addition, the coating composition may optionally contain other resins besides the hydroxyl-containing acrylic resin (A) and the amino-containing acrylic resin (E), curing catalysts, anti-fouling agents, anti-fungal agents, anti-settling agents, pigment dispersants, UV absorbers, light stabilizers, coating surface conditioners, etc.

[0051] Among these, examples of the other resins include acrylic resins other than the hydroxyl group-containing acrylic resin (A), alkyd resins, fluororesins, polyurethane resins, epoxy resins, silicone resins, combinations of these resins, and modified resins formed by compounding these resins. When other resins are contained, the content of the other resins is preferably within a range of 40 parts by mass or less, more preferably 30 parts by mass or less, per 100 parts by mass of the nonvolatile mass of the resin components contained in the main resin.

[0052] The stain-reducing agent may be an organosilicate compound, and specific examples of the organosilicate compound include tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra-isopropoxysilane, tetra-n-butoxysilane, tetra-isobutoxysilane, and tetra-tert-butoxysilane; monomethoxytriethoxysilane, monomethoxytripropoxysilane, monoethoxytripropoxysilane, monomethoxytributoxysilane, monoethoxytributoxysilane, and monopropoxytributoxysilane; dimethoxydiethoxysilane, dimethoxydipropoxysilane, diethoxydipropoxysilane, dimethoxydibutoxysilane, and diethoxydibutoxysilane; and partial hydrolysis / condensation products thereof.

[0053] When a stain-reducing agent is used, the amount used is preferably within the range of 0.1 to 30 parts by mass, and more preferably within the range of 1.0 to 20 parts by mass, based on 100 parts by mass of the non-volatile mass of the resin component contained in the main agent.

[0054] Application of coating composition (method of forming coating film): The two-component paint composition of the present invention is prepared by mixing the base resin and curing agent by a user such as a paint contractor before application. After application, the composition can be cured at room temperature, but it can also be cured by forced drying or heat.

[0055] The substrate to which the coating composition of the present invention can be applied is not particularly limited, but examples include inorganic substrates such as concrete, mortar, slate, slate roofing tiles, and ceramic building materials; resin substrates such as plastics; and metal substrates such as iron, steel plate, zinc plating, stainless steel, and aluminum, and these substrates may have an old coating film formed thereon.

[0056] Specific examples of the object to be coated include buildings and steel structures.

[0057] The two-component mixed coating composition of the present invention is applied by conventional methods such as spray coating, roller coating, brush coating, flow coating, etc., after diluting the two-component mixed coating with thinner or the like to a viscosity suitable for application. The amount of coating can be adjusted as appropriate, but is generally 30 to 400 g / m 2 It is preferable that the range is 50 to 250 g / m 2 is within the range.

[0058] In the present invention, after a primer coating is applied to the surface of the substrate, the two-component mixed coating composition may be applied as a topcoat coating.

[0059] The undercoat paint may be a known paint such as a sealer, a primer, a surface conditioner, or an anti-rust paint, depending on the type of substrate. The shape of the undercoat paint film formed may be flat or uneven. [Example]

[0060] The present invention will now be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the following examples, "parts" and "%" mean "parts by mass" and "% by mass," respectively.

[0061] Preparation of hydroxyl-containing acrylic resin (A): (Production Example 1) A manufacturing flask equipped with a thermometer, thermostat, stirrer, reflux condenser, nitrogen inlet tube, and dropping device was charged with 30 parts of "Swasol 1500" (Note 1), and the temperature was raised to 115°C. While stirring in a nitrogen stream, the monomer composition and catalyst mixture liquid having the following composition was added dropwise over 3 hours and mixed. <Monomer composition> 30 parts styrene 30 parts iso-butyl methacrylate 28 parts 2-ethylhexyl acrylate 2-Hydroxyethyl methacrylate 10 parts 2 parts methacrylic acid <Catalyst mixture> "Swasol 1500" (Note 1) 30 copies 2,2'-Azobis(2,4-dimethylvaleronitrile) 0.5 parts

[0062] Next, 30.5 parts of the catalyst mixture solution with the above composition was added dropwise at the same temperature over 1 hour, and after aging at 115°C for 1 hour, "Swasol 1500" (Note 1) was added so that the nonvolatile content was 50%, to obtain a hydroxyl-containing acrylic resin (A-1) solution. The nonvolatile content (NV) of the obtained hydroxyl-containing acrylic resin (A-1) solution was 50% by mass, the hydroxyl value was 40 mgKOH / g, and the weight-average molecular weight of the resin was 20,000.

[0063] (Note 1) "Swasol 1500": Product name, manufactured by Maruzen Oil Co., Ltd., aromatic mixed solvent, boiling point 183-208°C.

[0064] (Examples 2 to 9) Hydroxyl group-containing acrylic resin (A-2) to (A-6) solutions and amino group-containing acrylic resin (E-1) to (E-3) solutions were obtained in the same manner as in Production Example 1 above, except that the composition of the monomer composition to be added dropwise was changed as shown in Table 1 below.

[0065] [Table 1]

[0066] The abbreviations in Table 1 are explained as follows: St: styrene iBMA: iso-butyl methacrylate 2EHA: 2-ethylhexyl acrylate HEMA: 2-hydroxyethyl methacrylate MAA: methacrylic acid nBMA: n-butyl methacrylate DMAEMA: N,N-dimethylaminoethyl methacrylate DMAPMA: N,N-dimethylaminopropyl methacrylate Fatty acid modified monomer: Monomer with 8 parts of coconut oil fatty acid added to 5 parts of glycidyl methacrylate Silicone monomer: 3-methacryloxypropyltrimethoxysilane

[0067] Preparation of two-component coating compositions: (Examples 1 to 25, Comparative Examples 1 to 4) Each base paint (main agent) was prepared by mixing the base paint components listed in Tables 2 to 4 below, and each curing agent was prepared by mixing the curing agent components listed in Tables 2 to 4 below. The two were then mixed to prepare glossy and matte two-component paint compositions (X-1) to (X-29), which were then subjected to the following evaluations. The evaluation results are shown in Tables 2 to 4. The values ​​in the tables are actual blends.

[0068] [Table 2]

[0069] [Table 3]

[0070] [Table 4]

[0071] (Notes 1) to (Notes 8) in Tables 2 to 4 are as follows: (Note 1) Silica (b1): Average particle size 4.0 μm (Note 2) Silica (b2): Average particle size 6.0 μm (Note 3) Silica (b3): ​​Average particle size 9.5 μm (Note 4) Barium sulfate: precipitated barium sulfate, average particle size 0.7 μm (Note 5) Calcium carbonate: average particle size 4.5 μm (Note 6) Defoamer: Product name "DOWSIL FS 1265 Fluid": Dow Corning Toray Co., Ltd., fluorosilicone defoamer (Note 7) "Duranate TSS100": Trade name, nurate-modified hexamethylene diisocyanate, manufactured by Asahi Kasei Chemicals Corporation, NCO content 17.6% (Note 8) "Ethyl Silicate 48": Product name, manufactured by Colcoat Co., Ltd., ethyl silicate derivative, active ingredient 95%

[0072] Preparation of test panels: A tinplate (600 x 450 x 0.8 mm) was spray-painted with "Zaurus EXII" (trade name, Kansai Paint, one-component weak solvent epoxy rust preventative paint) diluted 15% with mineral spirits to a wet film thickness of 75 microns. The next day, a first topcoat was applied to the painted surface by mixing each of the paint compositions shown in Tables 2 to 4 in the base paint / hardener ratio shown in Tables 2 to 4, further diluting it 5% with mineral spirits, and applying it with a roller at a coating weight of 100 g / m. 2 It was painted so that it would look like this.

[0073] After the first coat of topcoat paint was applied, a one-day interval was allowed, and the same paint as the first coat was prepared in the same way as the second coat of topcoat paint, and applied with a roller at a coating rate of 100 g / m. 2 It was painted so that it would look like this.

[0074] After the second top coat, a touch-up coat was applied by brushing on a portion of the surface one day apart. Two types of paint were used for the touch-up coat: one was a paint composition shown in Tables 2 to 4 immediately after mixing it at the base paint / hardener ratio shown in Tables 2 to 4, and the other was a paint mixed at the base paint / hardener ratio shown in Tables 2 to 4 and left for three hours in a 40°C / 50% humidity environment.

[0075] Evaluation test: (*1) Finishing properties After applying two coats of topcoat paint, the finish of the painted surface was visually evaluated, with "○" and "△" indicating that the paint was usable. ○: Good with no uneven gloss △: Slight unevenness in gloss occurs ×: Significant uneven gloss and poor finish

[0076] (*2) Workability Of the paints used for repair painting, the workability of the paint was evaluated after mixing the base paint and hardener and leaving it in an environment of 40°C and 50% humidity for 3 hours. "◎" and "○" are usable. ◎: Good workability 〇: The viscosity of the paint increases slightly compared to the paint immediately after mixing the base paint and hardener, but there is no problem with workability. △: The viscosity of the paint increases compared to the paint immediately after mixing the base paint and hardener, making it slightly difficult to work with. ×: The viscosity of the paint is significantly higher than that of the paint immediately after mixing the base paint and hardener, making it difficult to work with.

[0077] (*3) Change in gloss over time after mixing the hardener The difference in gloss between the repaired area painted immediately after mixing the base paint and hardener and the repaired area painted with the paint that had been left for 3 hours in an environment of 40°C and 50% humidity after mixing was evaluated visually. "◎" and "○" indicate practical use. ◎: No difference in gloss, no problem ○: Gloss is slightly reduced after 3 hours of mixing compared to immediately after mixing the base paint and hardener. △: Gloss decreases after 3 hours of mixing compared to immediately after mixing the base paint and hardener. ×: Gloss is significantly reduced after 3 hours of mixing compared to immediately after mixing the base paint and hardener.

[0078] (*4)Water resistance After two coats of topcoat paint were applied, the painted panels were immersed in tap water at 23°C for 7 days, and the condition of the painted surface was observed and evaluated according to the following criteria. "◎" and "○" indicate that the product is suitable for practical use. ◎: No blisters observed, good ○: Very few tiny blisters are observed △: Blisters are observed in some parts of the coating ×: Blisters are observed over the entire surface of the coating film

[0079] As can be seen from Tables 2 to 4, Examples 1 to 25 all had excellent workability and showed little change in gloss over time after mixing the base resin and curing agent. From Example 2 and Comparative Example 1, Comparative Example 1, in which the hydroxyl group-containing acrylic resin (A) did not contain a carboxyl group, also showed decreased workability and water resistance. Comparative Examples 2 and 4, which did not contain the oxime compound (C), showed decreased workability and a large difference in gloss over time. Comparative Example 3, which contained 15 parts by mass of the oxime compound (C), showed excellent workability but decreased water resistance.

Claims

1. A two-component paint composition in which a base agent and a curing agent are mixed before painting, The composition comprises a base material containing a hydroxyl group-containing acrylic resin (A), a pigment component (B), and at least one oxime compound (C) selected from formamide oxime, acetamide oxime, acetoxime, diacetyl monooxime, benzophenone oxime, cyclohexanone oxime, methyl ethyl ketoxime, methyl isobutyl ketoxime, dimethyl ketoxime, and diethyl ketoxime, and a curing agent containing a polyisocyanate compound (D), the hydroxyl group-containing acrylic resin (A) has a carboxyl group, A two-component mixed coating composition, wherein the amount of the oxime compound (C) is within the range of 0.1 to 10 parts by mass based on 100 parts by mass of the nonvolatile content of the resin component contained in the main agent.

2. 2. The two-component coating composition according to claim 1, wherein the amount of the carboxyl group-containing polymerizable unsaturated monomer is 0.1 to 10 parts by mass based on 100 parts by mass of all polymerizable unsaturated monomer components used in producing the hydroxyl group-containing acrylic resin (A).

3. 3. The two-component coating composition according to claim 1, wherein the pigment component (B) comprises at least one type of inorganic particle (b) selected from barium sulfate, calcium carbonate, and silica.

4. 4. The two-component coating composition according to claim 3, wherein the inorganic particles (b) have an average particle size in the range of 0.1 to 10 μm.

5. The two-component coating composition according to any one of claims 1 to 4, further comprising an amino group-containing acrylic resin (E).

6. The two-component coating composition according to any one of claims 1 to 5, further comprising an antifoaming agent (F).

7. The two-component coating composition according to any one of claims 1 to 6, further comprising a weak solvent as the organic solvent (G).

8. A method for forming a coating film, comprising applying the two-component mixed coating composition according to any one of claims 1 to 7 to a substrate surface.

9. A method for forming a coating film, comprising applying an undercoat paint to a substrate surface and then applying the two-component mixed coating composition according to any one of claims 1 to 7 as a topcoat paint.

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