JP2008163204A - Base coating composition and coating composition containing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base coating composition which has a high non-volatile content when adjusted to a viscosity suitable for coating, preferably contains only a small amount of a regulated volatile organic compound, and is suitable for forming a coating film excellent in physical properties such as finishability and hardness, and to provide a coating composition containing the same. <P>SOLUTION: The base coating composition comprises an acrylic polyol (A), a polyester polyol (B) having a weight average molecular weight of 2,000-50,000, a hydroxyl value of 0.5-200 mgKOH/g, and a glass transition temperature of -70 to 0°C, and an organic solvent (C). The acrylic polyol (A) comprises styrene (a), a bridged alicyclic hydrocarbon group-containing polymerizable unsaturated monomer (b), and a hydroxyl group-containing polymerizable unsaturated monomer (c) as constituent monomer components, wherein the sum of (a) and (b) is 30 mass% or more of the constituent monomer components. The amount of (B) in the composition is 1-70 mass% based on the sum of (A) and (B). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  Conventionally, acrylic lacquers, acrylic urethane paints, aminoacrylic resin paints, etc. for painting and repairing exterior panels and parts of automobiles, painting and repairing industrial machines, buildings, structures, furniture (including steel) In particular, in the field of automotive repair coatings, acrylic urethane coatings containing a hydroxyl group-containing acrylic resin and a polyisocyanate compound are mainly used from the viewpoint of room temperature drying and durability.

  For hydroxyl group-containing acrylic resins used in this field, styrene is specified from the point of gloss of the final coating film, and isobornyl (meth) acrylate or tricyclodecanyl (meth) acrylate is specified from the point of polishing May be copolymerized in quantity.

  For example, Patent Document 1 discloses that the weight average molecular weight is 2000 or more and less than 20000 having a monomer component composed of styrene, isobornyl (meth) acrylate, a hydroxyl group-containing polymerizable unsaturated monomer, and other polymerizable unsaturated monomers. The weight average molecular weight is in the range of 20000 to 100,000, comprising as a constituent component a monomer component comprising a copolymer of styrene, isobornyl (meth) acrylate, a hydroxyl group-containing polymerizable unsaturated monomer, and other polymerizable unsaturated monomers. A coating composition containing a copolymer and a curing agent is described.

  Patent Document 2 discloses at least one monomer selected from styrene, isobornyl (meth) acrylate and tricyclodecanyl (meth) acrylate, an alkyl ester having 8 to 20 carbon atoms of methacrylic acid, and the number of carbon atoms of acrylic acid. A monomer component composed of at least one monomer selected from alkyl esters of 4 to 20 and other polymerizable unsaturated monomers not having a carboxyl group is used as a constituent component, and the weight average molecular weight and hydroxyl group weight within a specific range. A coating composition containing a coalescence and a polyisocyanate is described.

  According to these coating compositions, a coating film having high gloss and excellent abrasiveness can be formed, and the anti-modulation resistance is excellent. Therefore, the coating composition can be suitably used as a repair clear coating.

  By the way, as the coating specifications using the top coating in this field, for example, one-coat painting finish in which only the base coat paint is applied and two-coat finish in which the clear paint is applied after the base coat paint is applied are known.

  Base coat paints for finishing one coat are usually made of a copolymer of styrene for the purpose of giving gloss to the paint film. For this reason, it is known that cellulose components such as cellulose acetate butyrate are often blended.

  In general, this styrene copolymer resin and cellulose acetate butyrate have very poor compatibility, and paints containing both of these components have a problem that the pigment dispersibility and storage stability (pigment easily aggregates) are reduced. It is necessary to prepare primary color paints for toning according to the base coat paint for finishing one coat and the base coat for finishing two coats.

  In recent years, two-coat paint finishes are becoming mainstream in the self-repair field, but for white paint colors, there is much demand for one-coat paint finishes, and an assortment of white base coat paints for one-coat finishes is required. Yes. However, in the toning of the white paint color, it usually adjusts a slight yellowishness or blueness, and the primary color paint by the base coat paint for the 2-coat finish paint is used for the toning of the white base paint for the 1-coat finish. It was desired that it could be used as a seed.

  With regard to the above-mentioned problems, the applicant of the present invention disclosed in Patent Document 3 that a vinyl resin having a specific weight average molecular weight comprising a monomer component composed of styrene, a hydroxyl group-containing polymerizable unsaturated monomer, and other polymerizable unsaturated monomers as constituent components. And a specific coating composition for finishing one coat containing a specific cellulose acetate butyrate-modified vinyl resin and a polyisocyanate compound. According to this composition, even if a primary color paint based on a base coat paint for 2-coat finishing blended with cellulose acetate butyrate is used as a color type, a coating film having a high gloss feeling is formed without causing any trouble at the time of toning. However, there is a problem that the paint viscosity is high and the non-volatile content of the paint adjusted to a viscosity suitable for painting is low.

  In recent years, the impact of volatile organic compounds on the environment has become a problem, and organic solvents such as toluene and xylene that have been conventionally blended in the field of paints are regulated substances (for example, environmental pollutants). The actual situation is that they are registered as emission transfer registration (POLLUTANT RELEASE AND TRANSFER REGISTER, etc.), and that these organic solvents are required to be reduced or substantially free.

  Regarding such problems, for example, Patent Document 4 discloses a paint comprising a base paint and a diluent containing at least one organic solvent selected from a cellulose derivative, an acrylic resin, a polyester resin, an ester organic solvent, and a ketone organic solvent. A composition is described. According to such a coating composition, it is substantially free of regulated volatile organic compounds, is considered for the environment and the human body, and has storage stability, finish, drying, hardness, adhesion, etc. It is possible to form an excellent coating film, but when the composition is used for a monocoat finish, the finish and hardness of the formed coating film may not be sufficient. In addition to the above-described high solidification of the paint during coating, development of a product that is environmentally friendly and has excellent coating film properties such as finish and hardness of the formed coating film is required.

JP 2000-273393 A JP 2001-2979 A JP 2003-13000 A JP 2006-152259 A

  The object of the present invention is to provide a coating film having a high non-volatile content when adjusted to a viscosity suitable for coating, preferably a low content of regulated volatile organic compounds, and excellent physical properties such as finish and hardness. It is an object of the present invention to provide a base coating composition suitable for forming and a coating composition containing the same.

  As a result of intensive studies on the above-described problems, the present inventors have found that a specific acrylic polyol having a styrene and a bridged alicyclic hydrocarbon group-containing polymerizable unsaturated monomer and a hydroxyl group-containing polymerizable unsaturated monomer as a constituent component and a specific The present inventors have found that a base coating composition containing a polyester polyol having a property value at a specific blending ratio has a low viscosity relative to the coating non-volatile content, and has reached the present invention.

That is, the present invention
1. Acrylic polyol (A), polyester polyol (B) having a weight average molecular weight of 2,000 to 50,000, a hydroxyl value of 0.5 to 200 mgKOH / g, and a glass transition temperature in the range of −70 to 0 ° C. and organic The acrylic polyol (A) contains the solvent (C), and the styrene (a), the bridged alicyclic hydrocarbon group-containing polymerizable unsaturated monomer (b), and the hydroxyl group-containing polymerizable unsaturated monomer (c) are constituent monomers. The total amount of the polymerizable unsaturated monomer (b) having styrene (a) and a bridged alicyclic hydrocarbon group as a component is 30% by mass or more in the constituent monomer component, and the polyester polyol (B) The amount is in the range of 1 to 50% by weight based on the total amount of acrylic polyol (A) and polyester polyol (B). Paint composition,
2. The base coating composition according to 1, wherein the organic solvent (C) contains a ketone-based organic solvent in an amount of 1 to 50% by mass in the organic solvent (C) as part of its components.
3. The base coating composition according to 1 or 2, further comprising a pigment (D),
4). 4. The base coating composition according to 3, wherein the pigment (D) contains an extender pigment as a part of its components in the range of 0.5 to 80% by mass in the total pigment (D).
5. A two-component coating composition obtained by further blending a curing agent containing polyisocyanate (E) with the base coating composition according to any one of items 1 to 4,
6). The coating composition according to item 5, wherein the non-volatile content during coating is 50% by mass or more,
7). A coating method comprising applying the base coating composition or the coating composition according to any one of items 1 to 6 to a surface to be coated;
About.

  According to the base coating composition of the present invention, since the viscosity is low and the non-volatile content at the time of coating with a viscosity suitable for coating can be increased, a coating film can be formed efficiently and at the time of coating. It has the advantage that the amount of organic solvent released is small. Moreover, the coating film formed using the base coating composition of the present invention is excellent in gloss and coating film properties.

  The acrylic polyol (A) used in the present invention comprises styrene (a), a polymerizable unsaturated monomer (b) having a bridged alicyclic hydrocarbon group, and a hydroxyl group-containing polymerizable unsaturated monomer (c) as constituent monomer components. It is contained as

  In the present invention, the acrylic polyol (A) is a polymerizable unsaturated monomer (b) having a styrene (a) and a bridged alicyclic hydrocarbon group based on the total amount of monomer components constituting the acrylic polyol (A). In view of the gloss and hardness of the coating film formed using the base coating composition of the present invention, the total amount is 30% by mass or more, and the amount is particularly 45% by mass or more. Is preferred.

  In the acrylic polyol (A), the amount of styrene (a) used is in the range of 5 to 60% by mass, preferably 10 to 50% by mass, based on the monomer component constituting the acrylic polyol (A). Is preferable from the point of gloss of the coating film formed using the base coating composition of the present invention.

  Examples of the polymerizable unsaturated monomer (b) having a bridged alicyclic hydrocarbon group include compounds having a bridged alicyclic hydrocarbon group having 10 to 20 carbon atoms and a polymerizable unsaturated group. As typical examples of the bridged alicyclic hydrocarbon group having 10 to 20 carbon atoms, an isobornyl group, a tricyclodecanyl group, an adamantyl group, and the like can be given. Specific examples of the monomer include isobornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, adamantyl (meth) acrylate, 3,5-dimethyladamantyl (meth) acrylate, and 3-tetracyclododecyl (meth) acrylate. These can be used alone or in combination of two or more.

  The amount of the polymerizable unsaturated monomer (b) having a bridged alicyclic hydrocarbon group is 5 to 50% by mass, preferably 10 to 40% by mass, based on the monomer component constituting the acrylic polyol (A). % Within the range is preferable from the viewpoint of the gloss of the coating film formed using the base coating composition of the present invention.

  Examples of the hydroxyl group-containing polymerizable unsaturated monomer (c) include 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 2,3-dihydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth). Monoesterified product of polyhydric alcohol and acrylic acid or methacrylic acid such as acrylate or polyethylene glycol mono (meth) acrylate; ring-opening polymerization of ε-caprolactone to monoesterified product of polyhydric alcohol and acrylic acid or methacrylic acid Compounds such as “Placcel FA-1”, “Placcel FA-2”, “Placcel FA-3”, “Plaxel FA-4”, “Plaxel FA-5”, “Plaxel FM-1”, “Plaxel FM” -2 "," Placcel FM-3 "," Placque " "Lu FM-4", "Placcel FM-5" (all of which are manufactured by Daicel Chemical Co., Ltd., trade names) and the like. Can be used in combination.

  The amount of the hydroxyl group-containing polymerizable unsaturated monomer (c) used is 5 to 40% by mass, preferably 10 to 30% by mass, based on the monomer component constituting the acrylic polyol (A). The coating film formed by using the base coating composition of the present invention is desirable from the viewpoint of hardness and finish.

  In the said acrylic polyol (A), as a monomer component which comprises this acrylic polyol (A), another polymerizable unsaturated monomer (d) can be included as a part of the component. Such other polymerizable unsaturated monomer (d) can be copolymerized with the above monomers (a), (b) and (c), and other than the monomers (a), (b) and (c). Examples thereof include polymerizable unsaturated monomers such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) ) Acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate , N-nonyl (meth) acrylate, n-decyl (meth) acrylate, n-do Sil (meth) acrylate, n-tetradecyl (meth) acrylate, n-hexadecyl (meth) acrylate, n-octadecyl (meth) acrylate, stearyl (meth) acrylate, “isostearyl acrylate” (manufactured by Osaka Organic Chemical Co., Ltd.), etc. (Meth) acrylate having an alkyl group; (meth) acrylate having a cycloalkyl group such as cyclohexyl (meth) acrylate; carboxyl group-containing polymerizability such as (meth) acrylic acid, maleic acid, crotonic acid, and β-carboxyethyl acrylate Unsaturated monomer; Epoxy group-containing polymerizable unsaturated monomer such as glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate; N, N-dimethylaminoethyl (meth) acrylate, N, N-diethyl Aminoalkyl (meth) acrylates such as aminoethyl (meth) acrylate and N, N-dimethylaminopropyl (meth) acrylate; acrylamide, methacrylamide, N, N-dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (Meth) acrylamide or a derivative thereof such as (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N-methylol acrylamide, N-methylol acrylamide methyl ether, N-methylol acrylamide butyl ether; acrylonitrile, methacrylonitrile, Examples include vinyl acetate, Veova monomer (manufactured by Shell Chemical Co., Ltd.), vinyl toluene, and α-methylstyrene. These compounds can be used alone or in combination of two or more.

  In the present invention, the acrylic polyol (A) has a weight average molecular weight of 2,000 to 40,000, preferably 6,000 to 15,000. This is preferable from the viewpoint of workability.

  In this specification, the weight average molecular weight is a value obtained by converting the weight average molecular weight measured by gel permeation chromatograph (“HLC8120GPC” manufactured by Tosoh Corporation) based on the weight average molecular weight of polystyrene. Columns are “TSKgel G-4000H × L”, “TSKgel G-3000H × L”, “TSKgel G-2500H × L”, “TSKgel G-2000H × L” (both manufactured by Tosoh Corporation, trade names) ), Mobile phase: tetrahydrofuran, measurement temperature: 40 ° C., flow rate: 1 cc / min, detector: RI.

  Moreover, as a glass transition temperature of acrylic polyol (A), it is 30-90 degreeC, Preferably it exists in the range of 40-80 degreeC of the hardness of the coating film formed using the base coating composition of this invention. This is preferable from the viewpoint.

In this specification, the glass transition temperature (absolute temperature) is a value calculated by the following formula.
1 / Tg = W ₁ / T ₁ + W ₂ / T ₂ +... W _n / T _{n
Wherein, W 1, W 2 ··· W} n is the weight percent of each monomer [= (amount / monomer total weight of each monomer) × _{100], T 1, T 2 ··· T} n each It is the glass transition temperature (absolute temperature) of the homopolymer of the monomer. In addition, the glass transition temperature of the homopolymer of each monomer is a value according to Polymer Hand Book (4th Edition), and the glass transition temperature of a homopolymer of a monomer not described in the document is a weight average of the homopolymer of the monomer. Using a sample synthesized with a molecular weight of about 50,000, the glass transition temperature of the sample is measured using a differential scanning thermal analysis “DSC-50Q type” (trade name, manufactured by Shimadzu Corporation). After removing the solvent by vacuum suction, measure the change in calorie in the range of -100 ° C to + 100 ° C at a rate of temperature rise of 3 ° C / min, and use the first baseline change point on the low temperature side. .

  The polyester polyol (B) in the present invention can be produced by subjecting a polybasic acid and a polyhydric alcohol to a condensation reaction according to a conventional method.

  Examples of the polybasic acid include adipic acid, succinic acid, isophthalic acid, terephthalic acid, phthalic anhydride, maleic anhydride, trimellitic acid, hexahydrophthalic anhydride, sodium 5-sulfoisophthalate, and the like. Examples thereof include ethylene glycol, propylene glycol, glycerin, trimethylolpropane, neopentyl glycol, 1,6-hexanediol, pentaerythritol, sorbitol and the like. Furthermore, monobasic acids such as dehydrated castor oil fatty acid, linseed oil fatty acid, soybean oil fatty acid and tol oil fatty acid, benzoic acid, and fats and oils can be used as a copolymerization component.

  In the present invention, the polyester polyol (B) has a weight average molecular weight in the range of 2,000 to 50,000, preferably in the range of 5,000 to 25,000.

  When the weight average molecular weight of the polyester polyol (B) is less than 2,000, the drying property of the coating film formed using the base coating composition of the present invention may be remarkably deteriorated. As the viscosity of the composition increases, the coating workability of the coating composition including the base coating composition decreases or the non-volatile content at the time of coating decreases, which is not preferable.

  Further, the hydroxyl value of the polyester polyol (B) is preferably in the range of 0.5 to 200 mgKOH / g, and particularly preferably in the range of 40 to 140 mgKOH / g.

  If the hydroxyl value of the polyester polyol (B) is less than 0.5 mgKOH / g, the adhesion and water resistance of the coating film formed using the base coating composition of the present invention to the coated surface may be reduced. If it exceeds 200 mgKOH / g, the viscosity of the base coating composition increases, and the coating workability of the coating composition containing the base coating composition decreases or the non-volatile content during coating decreases, which is not preferable.

  The glass transition temperature of the polyester polyol (B) is in the range of −70 to 0 ° C., preferably in the range of −65 to −10 ° C.

  When the glass transition temperature of the polyester polyol (B) is less than −70 ° C., the drying property of the coating film formed using the base coating composition of the present invention is deteriorated. The coating workability of the coating composition containing the composition is undesirably lowered.

  The glass transition temperature of the polyester polyol (B) is determined by taking a sample into a measuring cup using a differential scanning thermal analysis “DSC-50Q type” (trade name, manufactured by Shimadzu Corporation) and removing the solvent by vacuum suction. The change in calorie is measured in the range of −100 ° C. to + 100 ° C. at a rate of temperature increase of 3 ° C./min, and the first baseline change point on the low temperature side is used.

  The organic solvent (C) contained in the base coating composition of the present invention is blended mainly from the viewpoint of production stability of the base coating composition, and conventionally known organic solvents can be used without limitation.

  In the present invention, it is possible to improve the compatibility between the resins contained in the base coating composition and the drying property of the formed coating film, so that as the organic solvent (C), for example, an ester organic solvent and a ketone organic It is suitable to use at least one organic solvent selected from solvents.

  Examples of the ester organic solvent in the organic solvent (C) include ethyl acetate, butyl acetate, isobutyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate, 3-methoxybutyl acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, Ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate, and the like. Examples of ketone organic solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, ethyl isoamyl ketone, diisobutyl ketone, methyl hexyl ketone, isophorone. These can be used alone or in combination of two or more.

  In the said organic solvent (C), when a ketone organic solvent is used especially, the viscosity of a base coating composition can be reduced, and a ketone organic solvent is 1-50 mass% in an organic solvent (C), especially 2-2%. It is preferable to contain 40% by mass.

  The organic solvent (C) can be mixed at any stage of the production of the base coating composition, or can be blended as a reaction solvent or a dilution solvent in the production of the resin contained in the coating.

  The base coating composition of the present invention contains the acrylic polyol (A), polyester polyol (B) and organic solvent (C), and the blending amount of the polyester polyol (B) is acrylic polyol (A) and polyester polyol. It is within the range of 1 to 70% by mass, preferably within the range of 5 to 55% by mass, based on the total amount of (B).

  When the blending amount of the polyester polyol (B) is less than 1% by mass, the viscosity of the coating composition containing the base coating composition of the present invention is increased and the coating workability is deteriorated or the non-volatile content at the time of coating is decreased. It is not preferable. On the other hand, if it exceeds 70% by mass, the drying property of the coating film formed using the base coating composition of the present invention is lowered, which is not preferable.

  The base coating composition of this invention can contain an organometallic compound as needed. Examples of the organometallic compound include tin octylate, dibutyltin di (2-ethylhexanoate), dioctyltin di (2-ethylhexanoate), dioctyltin diacetate, dibutyltin dilaurate, dibutyltin oxide, Dioctyltin oxide, dibutyltin fatty acid salt, lead 2-ethylhexanoate, zinc octylate, zinc naphthenate, fatty acid zincs, cobalt naphthenate, calcium octylate, copper naphthenate, tetra (2-ethylhexyl) titanate, etc. These may be used alone or in combination of two or more. These may be used in combination with known urethane curing catalysts such as tertiary amines and phosphoric acid compounds, if necessary.

  By including the organometallic compound, there is an effect of improving the drying property of the coating film in the case where a polyisocyanate curing agent described later is blended.

  The amount used is usually in the range of 0.01 to 10 parts by weight, preferably 0.02 to 5 parts by weight, based on 100 parts by weight of the total amount of resins contained in the base coating composition.

  As the pigment (D) used in the base coating composition, pigments such as luster pigments, colored pigments and extender pigments which are usually used in the paint field can be used without particular limitation.

  For example, metallic pigments such as aluminum powder, bronze powder, copper powder, tin powder, iron phosphide; mica, metal oxide coated mica powder, metal iron oxide coated alumina flake, metal oxide coated silica flake, mica Pearl luster-like pigments such as iron oxide, etc. Coloring pigments include white pigments such as titanium oxide; black pigments such as carbon black, acetylene black, lamp black, bone black, graphite, iron black, and aniline black Yellow pigments such as yellow iron oxide, titanium yellow, monoazo yellow, condensed azo yellow, azomethine yellow, bismuth vanadate, benzimidazolone, isoindolinone, isoindoline, quinophthalone, benzidine yellow, permanent yellow, etc .; permanent orange, etc. Red pigments such as red iron oxide, naphthol AS azo red, ansanthrone, anthraquinonyl red, perylene maroon, quinacridone red pigment, diketopyrrolopyrrole, watching red, permanent red; cobalt purple, quinacridone violet, di Purple pigments such as oxazine violet; blue pigments such as cobalt blue, phthalocyanine blue, and selenium blue; green pigments such as phthalocyanine green; and so on. Examples of extender pigments include zinc powder, barium sulfate, barium carbonate, and calcium carbonate. , Gypsum, clay, silica, white carbon, diatomaceous earth, talc, magnesium carbonate, alumina white, gloss white, mica powder and the like.

  When the pigment is blended in the base coating composition of the present invention, the blending amount can be appropriately adjusted according to the type of pigment, and is generally 1 based on the total mass of the resin contained in the base coating composition. It is appropriate to set it in the range of ˜250 mass%, preferably 2 to 240 mass%.

  In addition, it is preferable that the pigment (D) contains an extender pigment as a part of its components, because it can reduce the viscosity of the base coating composition and improve the workability of coating while improving the workability.

  Specific examples of extender pigments that can be used for such a purpose are as described above. Among them, the average particle diameter is 0.1 to 2 μm, particularly 0.15 to 1.0 μm. It is suitable from the viewpoint of workability and the color tone of the formed coating film.

  In the present specification, the particle size of each extender pigment is the average value of the lengths of line segments passing through the centers of the particles photographed in an image obtained by observation with an electron microscope. It is set as the average value of the particle diameter obtained in this way.

  The shape of the particles is not particularly limited, but a spherical shape is desirable because the viscosity of the base coating composition does not become too high and the non-volatile content can be designed high.

  In this specification, the term spherical includes not only a perfect sphere but also a slightly flat sphere, a sphere having a partially flat surface and / or a protrusion, and may be symmetric or asymmetric. .

  The amount of the extender is suitably in the range of 0.5 to 80% by mass, particularly 1 to 60% by mass in the total pigment (D).

  The base coating composition of the present invention further comprises, if necessary, a resin other than the above (A) and (B), a thickener, an ultraviolet absorber, a light stabilizer, an antioxidant, a surface conditioner, and a pigment dispersion. Additives for paints such as an agent and a curing catalyst can be blended.

  The base coating composition of the present invention obtained as described above can be applied after adjusting to a viscosity suitable for coating with a diluted thinner, but it is a two-component type by blending a curing agent containing polyisocyanate (E). It is suitable to use as a coating composition. In this case, it is desirable that the base coating composition and the curing agent component are mixed immediately before use, and if necessary, adjusted to a viscosity suitable for coating with a diluted thinner and used for coating.

  Examples of the polyisocyanate (E) applicable in such cases include compounds having two or more isocyanate groups in the molecule, and specific examples thereof include hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, dimer acid diisocyanate, Aliphatic diisocyanate compounds such as lysine diisocyanate; burette-type adducts, isocyanurate cycloadducts of these diisocyanate compounds; isophorone diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), methylcyclohexane-2,4- (or 2 , 6-) diisocyanate, 1,3- (or 1,4-) di (isocyanatomethyl) cyclohexane, 1,4-cyclohexane diisocyanate, 1,3-cyclopentanediiso Alicyclic diisocyanate compounds such as anate and 1,2-cyclohexane diisocyanate; bullet type adducts and isocyanurate cycloadducts of these diisocyanate compounds; xylylene diisocyanate, metaxylylene diisocyanate, tetramethyl xylylene diisocyanate, Tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, 1,4-naphthalene diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, (m-or p-) phenylene diisocyanate, 4,4'-biphenylene diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, bis (4-isocyanatofe Nyl) sulfone, aromatic diisocyanate compounds such as isopropylidenebis (4-phenylisocyanate); bullet type adducts, isocyanurate cycloadducts of these diisocyanate compounds; triphenylmethane-4,4 ′, 4 ″ ″ -Triisocyanate, 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene, 4,4′-dimethyldiphenylmethane-2,2 ′, 5,5′-tetraisocyanate, etc. Polyisocyanate compounds having three or more isocyanate groups in one molecule; burette type adducts, isocyanurate cycloadducts of these polyisocyanate compounds; ethylene glycol, propylene glycol, 1,4-butylene glycol, dimethylolpropion Acid, polyalkylene Urethane adducts made by reacting polyisocyanate compounds in excess ratio of isocyanate groups to hydroxyl groups of polyols such as coal, trimethylolpropane, hexanetriol, etc .; bullet type addition of these urethanized adducts And polyisocyanate compounds such as isocyanurate cycloadducts.

  The blending ratio of the base coating composition and the curing agent component containing polyisocyanate is generally 0.1% in terms of an equivalent ratio of NCO / OH with respect to the hydroxyl group in the resin contained in the base coating composition. It is appropriate to be within a range of 2 to 3.0, preferably 0.5 to 1.5.

  The base coating composition of the present invention and the coating composition containing the base coating composition can be of a high solid type, and the amount of volatile substances emitted during coating can be reduced. Specifically, the coating material non-volatile content at the time of coating can be 50 mass% or more, especially 60 mass% or more.

  In this specification, the non-volatile content at the time of coating was measured by weighing 1.0 g of a sample immediately before coating, adjusted to a viscosity suitable for coating under conditions of a temperature of 20 ° C. and a humidity of 60%, to a heating temperature of 105 ° C., It can be determined by removing the evaporation component in 3 hours and calculating the remaining amount as a mass percentage.

  The base coating composition and the coating composition containing the same are iron, aluminum, brass, copper plate, stainless steel plate, tin plate, galvanized steel plate, alloyed zinc (Zn-Al, Zn-Ni, Zn-Fe, etc.) A) Metals such as plated steel sheets; surface-treated metals obtained by subjecting these metal surfaces to chemical conversion treatment such as phosphate treatment and chromate treatment; directly or directly on the material to be coated such as plastic, wood, concrete, mortar, etc. Can be applied to the cured or uncured coating surface of the coated material coated with primer and / or intermediate coating and / or top coating coloring base on the coating material. An excellent coating film can be formed.

  Specific examples of the coated surface include, but are not limited to, vehicles such as passenger cars, trucks, buses, motorcycles, and trains; aircraft; buildings; home appliances.

  The coating means is not particularly limited, such as spray coating, electrostatic coating, brush coating, roller coating, and the drying method may be any of heat drying, forced drying, and room temperature drying.

  Further, in the coating method of the present invention, the base coating composition of the present invention and the coating composition containing the same are used for monocoating finishes only by coating, thereby being excellent in gloss, finish, hardness, etc. However, if necessary, a conventionally known clear paint can be applied onto the formed coating film to form a 2-coat finish.

  Hereinafter, the present invention will be described in more detail with reference to examples. Here, “parts” and “%” mean “parts by mass” and “% by mass”, respectively.

Production of copolymer solution Production Example 1
A reaction vessel equipped with a stirrer, thermometer, reflux condenser, thermostat and dropping pump was charged with 60 parts of butyl acetate, heated to 125 ° C. with stirring, and a mixture of the following monomer and polymerization initiator: Was dropped at a constant rate over 3 hours using a dropping pump. After completion of the dropwise addition, the reaction was terminated by aging for 2 hours at the same temperature. The obtained copolymer solution (A1) had a non-volatile content of 60%, the copolymer had a weight average molecular weight of 10,000 and a glass transition temperature of 73 ° C.
Styrene 40 parts isobornyl acrylate 25 parts isobutyl methacrylate 2 parts 2-ethylhexyl acrylate 5 parts 2-hydroxyethyl methacrylate 28 parts t-butylperoxy-2-ethylhexanoate 6.1 parts.

Production Example 2
In the said manufacture example 1, the copolymer solution (A2) was obtained like the said manufacture example 1 except having set the dripped material as the following composition. The obtained copolymer solution (A2) had a nonvolatile content of 60%, a weight average molecular weight of 10,000, and a glass transition temperature of 43 ° C.
Styrene 40 parts isobornyl acrylate 20 parts 2-ethylhexyl acrylate 13.5 parts 2-hydroxyethyl methacrylate 19 parts 2-hydroxyethyl acrylate 7.5 parts t-butylperoxyhexanoate 6.1 parts.

Production Example 3
A reaction vessel equipped with a stirrer, thermometer, reflux condenser, thermostat and dropping pump was charged with 60 parts of butyl acetate, heated to 115 ° C. with stirring, and a mixture of the following monomers and polymerization initiator: Was dropped at a constant rate over 3 hours using a dropping pump. After completion of the dropwise addition, the reaction was terminated by aging for 2 hours at the same temperature. The obtained copolymer solution (A3) had a nonvolatile content of 55%, the copolymer had a weight average molecular weight of about 26000, and a glass transition temperature of 43 ° C.
Styrene 40 parts Isobornyl acrylate 20 parts n-butyl acrylate 21 parts 2-hydroxyethyl methacrylate 19 parts t-butyl peroxyhexanoate 1.7 parts.

Production Example 4
A copolymer solution (A4) was obtained in the same manner as in Production Example 1 except that the dropped product had the following composition in Production Example 1. The obtained copolymer solution (A4) had a nonvolatile content of 60%, a weight average molecular weight of 10,000, and a glass transition temperature of 55.4 ° C.
Styrene 10 parts isobornyl acrylate 15 parts isobutyl methacrylate 42 parts 2-ethylhexyl acrylate 5 parts 2-hydroxyethyl methacrylate 28 parts t-butyl peroxy-2-ethylhexanoate 6.1 parts.

Production Example 5
The following components were charged in a reactor equipped with a heating apparatus, a thermometer, a stirrer, a rectifying column, and a reflux condenser attached with a water separator, and heated to 160 ° C. to 230 ° C. over 3 hours.
Hexahydrophthalic anhydride 26.7 parts Adipic acid 28 parts Neopentyl glycol 5.3 parts 1,6-hexanediol 40 parts This was kept at 230 ° C. for 1 hour, and the resulting condensed water (7.4 parts) was added. It was distilled off using a rectifying column. Subsequently, 5 parts of butyl acetate was added, butyl acetate and condensed water were refluxed, and water was removed using a water separator. After 2 hours from the addition of butyl acetate, the acid value was measured, and when the acid value became 2 or less, it was cooled to 120 ° C., diluted with butyl acetate to a non-volatile content of 70%, and the polyester resin solution (B1 ) The resin of the resin solution had a weight average molecular weight of 20,000, a hydroxyl value of 55, and a glass transition temperature of −60 ° C.

Production Example 6
In Production Example 5, a polyester resin solution (B2) was obtained in the same manner as Production Example 5 except that the composition was changed to the following composition.
Hexahydrophthalic anhydride 33 parts Adipic acid 16 parts Neopentyl glycol 30 parts 1,6-hexanediol 21 parts The resin resin has a weight average molecular weight of 20,000, a hydroxyl value of 53, and a glass transition temperature of- It was 10 ° C.

Production Example 7
In Production Example 5, a polyester resin solution (B3) was obtained in the same manner as Production Example 5 except that the composition was changed to the following composition.
Hexahydrophthalic anhydride 34 parts Adipic acid 13 parts Neopentyl glycol 28 parts 1,6-Hexanediol 25 parts The resin solution has a weight average molecular weight of 12,000, a hydroxyl value of 120, and a glass transition temperature of- It was 12 ° C.

Production Example 8
In Production Example 5, a polyester resin solution (B4) was obtained in the same manner as Production Example 5 except that the composition was changed to the following composition.
Hexahydrophthalic anhydride 24 parts Adipic acid 24 parts Neopentyl glycol 13 parts 1,6-hexanediol 39 parts The resin solution has a weight average molecular weight of 13,000, a hydroxyl value of 120, and a glass transition temperature of- It was 55 ° C.

Production of pigment dispersion paste Production Examples 9 to 18
Each copolymer solution and resin solution obtained in the above production examples were blended in the blending amounts shown in Table 1, and further a titanium oxide pigment having an average particle size of 0.25 to 0.3 μm, a pigment dispersant (“BYK161”, Trade names, BYK-chemie), extender pigments (spherical precipitated barium sulfate with an average particle size of 0.6 μm, spherical calcium carbonate with an average particle size of 0.6 μm, scaly talc), butyl acetate are listed in Table 1. After stirring for about 20 minutes with a disper, the mixture was dispersed with a sand mill to obtain each pigment dispersion paste.

Preparation of 1-coat finish white paint Examples 1-22 and Comparative Examples 1-4
Each component is prepared by mixing the components shown in Table 2 below, and after adding a curing agent (Note 2) according to Table 2, the diluted thinner (Note 3) causes the nonvolatile content to be 65% by mass. The white paint was prepared respectively. Table 2 shows the viscosity of each diluted white paint. Each diluted white paint was spray-coated on a process board coated with a new car white paint at a temperature of 20 ° C. so as to have a dry film thickness of 60 μm to obtain each test coated board. These were evaluated by the following methods and standards. The evaluation results are shown in Table 2.

Evaluation Criteria (* 1) Paint Viscosity: Each diluted white paint was adjusted to 20 ° C., filled into an iwata cup, and the time until the entire amount was discharged was measured using a stopwatch.
(* 2) Feeling of painting: Feeling of painting at the time of spray painting (◎: very good, ○: good, △: slightly inferior, x: inferior)
(* 3) Finishability: The gloss of each test coated plate was visually determined. (◎: Very good gloss, ○: Good gloss, △: Inferior gloss, ×: Very low gloss and poor)
(* 4) Dryability: Each diluted white paint obtained above is applied to a glass plate with a doctor blade in a constant temperature and humidity chamber at a temperature of 20 ° C. and a humidity of 75% so that the coating film thickness is 100 μm. Then, the touch drying time until the paint did not touch the finger when touched with a finger was measured (◎: drying time less than 5 minutes, ○: drying time 5 minutes or more and less than 10 minutes, Δ: 10 or more and less than 15 minutes. , X: 15 minutes or more)
(* 5) Water resistance: Each test coated plate was allowed to stand in a constant temperature and humidity chamber at a temperature of 20 ° C. and a humidity of 75% for 7 days, and then the coated surface state after being immersed in tap water at 20 ° C. for 7 days was examined ( : No abnormality, Δ: glossy, ×: blistering).
(* 6) Adhesiveness: Each test coated plate immersed in tap water in (* 5) above is immediately wiped off with a cloth and cut to reach the substrate with 100 2 mm square grids to the substrate. A tape peel test was performed (◯: 90 or more remaining grids, Δ: 50 to 89 remaining grids, ×: 50 or fewer remaining grids).
(Note 1) “STANN BL”: Sankyo Co., Ltd., dibutyltin dilaurate (Note 2) “Duranate TPA100”: Asahi Kasei Co., Ltd., polyisocyanate (Note 3) “Retan PG Eco thinner 20”: Kansai Paint , Dilution thinner

Claims (7)

Acrylic polyol (A), polyester polyol (B) having a weight average molecular weight of 2,000 to 50,000, a hydroxyl value of 0.5 to 200 mgKOH / g, and a glass transition temperature in the range of −70 to 0 ° C. and organic A monomer containing a solvent (C), wherein the acrylic polyol (A) comprises styrene (a), a bridged alicyclic hydrocarbon group-containing polymerizable unsaturated monomer (b), and a hydroxyl group-containing polymerizable unsaturated monomer (c). The total amount of the polymerizable unsaturated monomer (b) having styrene (a) and a bridged alicyclic hydrocarbon group as a component is 30% by mass or more in the constituent monomer component, and the polyester polyol (B) The bait is characterized in that the blending amount is in the range of 1 to 70% by mass based on the total amount of the acrylic polyol (A) and the polyester polyol (B). The coating composition. The base coating composition according to claim 1, wherein the organic solvent (C) contains a ketone-based organic solvent in an amount of 1 to 50 mass% in the organic solvent (C) as a part of the component. The base coating composition according to claim 1 or 2, further comprising a pigment (D). The base coating composition according to claim 3, wherein the pigment (D) contains an extender pigment as a part of its components in the range of 0.5 to 80% by mass in the total pigment (D). A two-component coating composition obtained by further blending a base coating composition according to any one of claims 1 to 4 with a curing agent containing polyisocyanate (E). The coating composition according to claim 5, wherein a non-volatile content at the time of coating is 50% by mass or more. A base coating composition or a coating composition according to claim 1 is applied to a surface to be coated.