JP6188216B2 - Coating composition and coated article - Google Patents

Description

  The present invention relates to a coating composition and a coated article that can form a coating film having good tactile sensation and excellent chemical resistance even when a coating film is formed on one surface of a substrate.

Electrical and electronic equipment-related parts such as personal computer casings, automotive interior parts such as instrument panels, center consoles, dashboards, door trims, etc., life-related parts such as chair legs, armrests, handrails, window frames, door knobs, and furniture building materials A matte paint film is usually formed by applying a matte paint to plastic products in applications such as parts from the viewpoint of design such as profound feeling and luxury. In recent years, such matte coatings have been required to have a better touch feeling. For example, in Patent Document 1, a soft two-component urethane paint having resin beads in a main agent paint is applied to plastic parts. Has proposed a method for forming a coating film having a leather-like texture and appearance on the plastic surface.

  Further, in Patent Document 2, a specific two-component curable polyurethane coating composition having urethane resin beads and an organic matting agent has a tactile sensation and an appearance that are compatible with softness, moistness, and smoothness. It is disclosed that it is possible to form a coating film having scratch resistance, oil-fat resistance, and the like. Further, Patent Document 3 discloses a two-component urethane on a plastic substrate surface for the purpose of reducing sweat resistance and gloss unevenness. A method for forming a multilayer film is proposed in which a primer coating film layer is formed using a paint, and then a top coating film layer is formed using a two-pack type urethane paint containing an inorganic matting agent and urethane resin beads. .

Japanese Patent Laid-Open No. 9-253577 JP-A-2005-139273 JP2008-006421

  However, although a tactile sensation can be obtained by the above-mentioned method, all of them have insufficient chemical resistance when a coating film is formed on one surface of the base material. For example, hand cream, lotion used for sun protection, liquid foundation, etc. When the composition for external use containing an ultraviolet absorber, an antiseptic and an emulsifier is left on the coating film surface, poor adhesion of the coating film, a decrease in appearance, a decrease in hardness, and the like may occur.

  An object of the present invention is to provide a coating composition and a coated article that can form a coating film having good tactile sensation and excellent chemical resistance even when a coating film is formed on one surface of a substrate. That is.

As a result of intensive studies in order to solve the above-mentioned problems, the present inventors have developed a coating composition comprising a specific hydroxyl group-containing acrylic resin, a main component containing a hydroxyl group-containing polyester resin and resin beads, and a polyisocyanate curing agent. It has been found that the above problems can be solved by using a product, and the present invention has been completed.

  That is, the present invention is a coating composition comprising a main component containing a hydroxyl group-containing acrylic resin (A), a hydroxyl group-containing polyester resin (B) and a resin bead (C), and a polyisocyanate curing agent, the hydroxyl group-containing acrylic resin (A) includes a hydroxyl group-containing acrylic resin (A1) having a hydroxyl value of 100 to 250 mgKOH / g, a weight average molecular weight of 5,000 to 50,000, and a glass transition temperature of −25 ° C. or less, and resin beads (B) The present invention relates to a coating composition characterized by containing 20 to 80% by mass based on the total solid mass in the main agent, and a coated article obtained by coating the substrate surface with the coating composition.

  According to the coating composition of the present invention, even when a coating film is formed on the substrate surface with a single coat, it has a good tactile sensation and the hand cream or the lotion used for sun protection remains attached to the coating film surface. Even if it is left as it is, it is possible to form a coating film that does not cause poor adhesion of the coating film, a decrease in appearance, a decrease in hardness, or the like, that is, has excellent chemical resistance.

  The coating composition of the present invention comprises a main component containing a hydroxyl group-containing acrylic resin (A), a hydroxyl group-containing polyester resin (B) and resin beads (C), and a polyisocyanate curing agent.

  The hydroxyl group-containing acrylic resin (A) used in the present invention is usually obtained by copolymerizing a hydroxyl group-containing polymerizable unsaturated monomer and other copolymerizable polymerizable unsaturated monomers by a known polymerization method such as solution polymerization. Can be manufactured by.

  Examples of the hydroxyl group-containing polymerizable unsaturated monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6- Monoesterified products of polyhydric alcohols such as hydroxyhexyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol (meth) acrylate and (meth) acrylic acid, and the polyhydric alcohol and (meth) acrylic acid A compound obtained by ring-opening polymerization of ε-caprolactone, and the like, can be used, and these can be used alone or in combination of two or more. Of these, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate are preferably used from the viewpoints of the feel and chemical resistance of the obtained coating film. it can.

Other copolymerizable 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, 2-ethylhexyl acrylate, cyclohexyl (meth) acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate, isobornyl (meth) acrylate, stearyl (meth) acrylate (Meth) acrylic acid alkyl esters such as; (meth) acrylic acid, maleic acid, maleic anhydride and other carboxyl group-containing polymerizable unsaturated monomers; N, N-dimethylaminoethyl (meth) acrylate, N, -Aminoalkyl (meth) acrylates such as diethylaminoethyl (meth) acrylate and N, N-dimethylaminopropyl (meth) acrylate; acrylamide, methacrylamide, N, N-dimethylaminoethyl (meth) acrylamide, N, N-diethylamino (Meth) acrylamide or a derivative thereof such as ethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N-methylolacrylamide, N-methylolacrylamide methyl ether, N-methylolacrylamide butyl ether; 2- (methacryloyloxy) ) Quaternary ammonium base-containing monomers such as ethyltrimethylammonium chloride and 2- (methacryloyloxy) ethyltrimethylammonium bromide; (Meth) acrylamide-alkanesulfonic acid such as chloramido-2-methylpropanesulfonic acid, sulfoalkyl (meth) acrylate such as 2-sulfoethyl (meth) acrylate; acrylonitrile, methacrylonitrile, vinyl acetate, styrene, vinyltoluene, α -Methylstyrene; Polyvinyl compounds such as allyl methacrylate; -Hydrolysis of-(meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane, γ- (meth) acryloyloxypropylmethyldimethoxysilane Reactive silyl group-containing polymerizable unsaturated monomers and the like, and these can be used alone or in combination of two or more. Of these, alkyl esters of (meth) acrylic acid in which the alkyl moiety has 4 to 8 carbon atoms can be suitably used, particularly from the viewpoint of the feel of the coating film obtained and chemical resistance.
In the present specification, “(meth) acrylate” means acrylate or methacrylate, and “(meth) acrylic acid” means acrylic acid or methacrylic acid. “(Meth) acryloyl” means acryloyl or methacryloyl, and “(meth) acrylamide” means acrylamide or methacrylamide.

  The copolymerization of the polymerizable unsaturated monomer is preferably a copolymerization by a solution polymerization method. For example, a mixture of the polymerizable unsaturated monomer and the radical polymerization initiator is dissolved or dispersed in an organic solvent. Examples of the polymerization method include heating at 80 ° C. to about 200 ° C. with stirring for about 1 to 10 hours.

  In the present invention, the hydroxyl group-containing acrylic resin (A) has a hydroxyl value of 100 to 250 mgKOH / g, preferably 150 to 200 mgKOH / g, and a weight average molecular weight of 5,000, from the viewpoint of the touch and chemical resistance of the resulting coating film. It contains a hydroxyl group-containing acrylic resin (A1) having a viscosity of ˜50,000, preferably 8,000 to 30,000, a glass transition temperature of −25 ° C. or lower, preferably −30 to −70 ° C.

In the present specification, the glass transition temperature Tg of the hydroxyl group-containing acrylic resin is a value calculated by the following formula.
1 / Tg (K) = W1 / T1 + W2 / T2 +... Wn / Tn
Tg (° C.) = Tg (K) -273
In the formula, W1, W2,... Wn are mass fractions of the respective monomers, and T1, T2... Tn are glass transition temperatures Tg (K) of the homopolymers of the respective monomers.
In addition, the glass transition temperature of the homopolymer of each monomer is POLYMER HANDBOOK Fourth Edition, J. MoI. Brandrup, E .; h. Immergut, E .; A. The glass transition temperature of a monomer not described in the literature, which is a value according to Grulk (1999), was synthesized by synthesizing a homopolymer of the monomer so that the weight average molecular weight was about 50,000, and its glass transition The value when the temperature is measured by differential scanning thermal analysis is used.

  Further, in this specification, the weight average molecular weight and the number average molecular weight are the retention time (retention capacity) measured using a gel permeation chromatograph (GPC), and the retention time of standard polystyrene with a known molecular weight measured under the same conditions ( It is a value obtained by converting to the molecular weight of polystyrene by (retention capacity). 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 ml / min, detector: RI.

  The hydroxyl group-containing polyester resin (B) used in the present invention can be usually obtained by esterifying a polybasic acid and a polyhydric alcohol with an excess of hydroxyl groups by a method known per se.

  A polybasic acid is a compound having two or more carboxyl groups in one molecule. For example, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, diphenylmethane-4,4 Aromatic polybasic acids such as' -dicarboxylic acid and anhydrides thereof; alicyclic dicarboxylic acids such as hexahydroisophthalic acid, hexahydroterephthalic acid, hexahydrophthalic acid and tetrahydrophthalic acid and anhydrides; adipic acid, sebacin Aliphatic polybasic acids such as acid, suberic acid, succinic acid, glutaric acid, maleic acid, chloromaleic acid, fumaric acid, dodecanedioic acid, pimelic acid, azelaic acid, itaconic acid, citraconic acid and dimer acid and their anhydrides Lower alkyl esters such as methyl esters and ethyl esters of these dicarboxylic acids Trimellitic acid, trimellitic anhydride, pyromellitic acid, pyrometic anhydride, trimesic acid, methylcyclohexenticarboxylic acid, tetrachlorohexene polybasic acid, and polybasic acids having three or more valences such as anhydrides thereof .

  The polyhydric alcohol is a compound having two or more hydroxyl groups in one molecule. For example, ethylene glycol, propylene glycol, diethylene glycol, trimethylene glycol, tetraethylene glycol, triethylene glycol, dipropylene glycol, 1,4- Butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-butanediol, 3-methyl-1,2-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1 , 4-pentanediol, 2,4-pentanediol, 2,3-dimethyltrimethylene glycol, tetramethylene glycol, 3-methyl-4,3-pentanediol, 3-methyl-4,5-pentanediol, 2, 2,4-trimethyl-1,3-pentanediol, 1 Dihydric alcohols such as 6-hexanediol, 1,5-hexanediol, 1,4-hexanediol, 2,5-hexanediol, neopentyl glycol, and hydroxypivalic acid neopentyl glycol ester; these dihydric alcohols Lactones such as ε-caprolactone added thereto; ester diols such as bis (hydroxyethyl) terephthalate; alkylene oxide adducts of bisphenol A, polyether diols such as polyethylene glycol, polypropylene glycol, and polybutylene glycol ; Α-olefin epoxides such as propylene oxide and butylene oxide, Cardura E10 [manufactured by Shell Chemical Co., Ltd., trade name, glycidyl ester of synthetic hyperbranched saturated fatty acid], etc. Epoxy compounds; trivalent or higher alcohols such as glycerin, trimethylolpropane, trimethylolethane, diglycerin, triglycerin, 1,2,6-hexanetriol, pentaerythritol, dipentaerythritol, sorbitol, mannitol; Polylactone polyols obtained by adding a lactone such as ε-caprolactone to an alcohol having a valency or higher; 1,4-cyclohexanedimethanol, tricyclodecane dimethanol, hydrogenated bisphenol A, hydrogenated bisphenol F, hydrogenated bisphenol A, and Examples thereof include alicyclic polyhydric alcohols such as hydrogenated bisphenol F.

  Introduction of a hydroxyl group can be performed, for example, by using a polyhydric alcohol having 3 or more hydroxyl groups in one molecule.

  Moreover, you may use a monobasic acid, an oil component (this fatty acid is also included), etc. as needed at the time of reaction of the said polybasic acid and a polyhydric alcohol. Examples of the monobasic acid include benzoic acid and t-butylbenzoic acid, and examples of the oil component include castor oil, dehydrated castor oil, safflower oil, soybean oil, linseed oil, tall oil, coconut oil, and the like. These fatty acids etc. are mentioned, These can be used 1 type or 2 or more types. Furthermore, the polyester resin may be modified with an epoxy compound such as butyl glycidyl ether, alkylphenyl glycidyl ether, or neodecanoic acid glycidyl ester, if necessary.

  In the present invention, the hydroxyl group-containing polyester resin (B) has a hydroxyl value of 50 to 200 mgKOH / g, preferably 50 to 150 gKOH / g, and a number average molecular weight of 2,000 from the viewpoints of the touch and chemical resistance of the resulting coating film. It is desirable to contain ˜20,000, preferably 2,000 to 10,000 hydroxyl group-containing polyester resin (B1).

  Furthermore, in the present invention, from the viewpoint of improving the chemical resistance of the coating film obtained, the hydroxyl group-containing polyester resin (B1) is obtained by a reaction between a polyhydric alcohol containing a cyclic polyol compound (b1) having a nurate structure and a polybasic acid. The hydroxyl group-containing polyester resin (B1-1) is desirable.

  Examples of the cyclic polyol compound (b1) having a nurate structure include tris (hydroxyalkyl) isocyanurate such as tris (hydroxyethyl) isocyanurate, tris (hydroxypropyl) isocyanurate and tris (hydroxybutyl) isocyanurate, the tris Ε-caprolactone modified form of (hydroxyalkyl) isocyanurate, tris (hydroxyethyl) isocyanurate, diol compound and dicarboxylic acid, and the hydroxyl group in tris (hydroxyethyl) isocyanurate and diol compound is converted to a carboxyl group in dicarboxylic acid. Esterified tris (hydroxyethyl) isocyanurate obtained by reacting in excess, and polyisocyanate compound having nurate structure and diolization And things, hydroxyl groups in the diol compound is the reaction product obtained by reacting with excess state to isocyanate groups in the polyisocyanate compounds and the like having a isocyanurate structure. These can be used alone or in combination of two or more.

  Among these, from the viewpoint of chemical resistance of the resulting coating film, tris (2-hydroxyethyl) isocyanurate and ε-caprolactone modified form of tris (2-hydroxyethyl) isocyanurate are preferable, and tris (2-hydroxy More preferred is ethyl) isocyanurate.

  The content ratio of the cyclic polyol compound (b1) having a nurate structure in the hydroxyl group-containing polyester resin (B1-1) is from 1 to 75 mol% based on the total amount of alcohol components from the viewpoint of chemical resistance of the resulting coating film. Is preferably within the range of 10 to 60 mol%.

  The use ratio of the hydroxyl group-containing acrylic resin (A) and the hydroxyl group-containing polyester resin (B) is 40/60 to 90/10 based on the total solid content of both from the viewpoint of the feel of the coating film and chemical resistance. , Preferably, it is in the range of 50/50 to 90/10. Further, the content of the hydroxyl group-containing acrylic resin (A1) is based on the total solid content of the hydroxyl group-containing acrylic resin (A) and the hydroxyl group-containing polyester resin (B) from the viewpoint of the feel of the coating film and chemical resistance obtained. It is desirable to be in the range of 50 to 90% by mass, preferably 60 to 80% by mass. Furthermore, the content of the hydroxyl group-containing polyester resin (B1) is based on the total solid content of the hydroxyl group-containing acrylic resin (A) and the hydroxyl group-containing polyester resin (B) from the viewpoint of the feel of the coating film obtained and chemical resistance. Desirably, the content is in the range of 10 to 60% by mass, preferably 20 to 50% by mass, and the content of the hydroxyl group-containing polyester resin (B1-1) is a hydroxyl group from the viewpoint of the touch and chemical resistance of the resulting coating film. Based on the total solid content of the containing acrylic resin (A) and the hydroxyl group-containing polyester resin (B), it is 10 to 50% by mass, preferably 20 to 40% by mass.

  In the present invention, a film-forming resin component other than the hydroxyl group-containing acrylic resin (A) and the hydroxyl group-containing polyester resin (B) may be appropriately contained in the main agent as long as it does not affect the coating performance such as touch feeling. The content is desirably 40% by mass or less, particularly 30% by mass or less, based on the total solid content mass with the hydroxyl group-containing polyester resin (A).

  Examples of the resin beads (C) used in the present invention include polyethylene resin beads, polypropylene resin beads, acrylic resin beads, urethane resin beads, polyester resin beads, polyamide resin beads, polystyrene resin beads, silicone resin beads, melamine resin beads, Examples include fluororesin beads, polybutadiene resin beads, polyethylene resin beads, polyacrylonitrile resin beads, phenol resin beads, and nylon resin beads, and these can be used alone or in combination of two or more. These may be hollow or solid. In addition, amorphous crosslinked rubber particles and the like can also be used as the resin beads (C). Among these, urethane resin beads can be preferably used from the viewpoint of the touch of the formed coating film, particularly the moist feeling.

  The resin beads (C) desirably have an average particle diameter of 0.1 to 30 μm, preferably 0.5 to 15 μm from the viewpoint of finish. Here, the average particle diameter is a median diameter (d50) of a volume-based particle size distribution measured by a laser diffraction scattering method, and can be measured using, for example, a microtrack particle size distribution measuring apparatus manufactured by Nikkiso Co., Ltd.

  Content of the said resin bead (C) is 20-80 mass% on the basis of the total solid content mass in a main ingredient, Preferably it is the range of 30-70 mass%. Outside this range, the tactile sensation and smoothness of the formed coating film are insufficient, which is not preferable.

  The polyisocyanate curing agent used in the present invention contains a polyisocyanate compound (D).

  Examples of the polyisocyanate compound (D) include aliphatic polyisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, dimer acid diisocyanate and lysine diisocyanate; burette type adducts of these aliphatic polyisocyanates, isocyanurate rings Adducts, allophanate type adducts, uretdione type adducts; alicyclic diisocyanates such as isophorone diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), methylcyclohexane-2,4- or -2,6-diisocyanate; Of alicyclic diisocyanates of burette type, isocyanurate cycloadducts; xylylene diisocyanate, tetramethylxylylene diiso Aromatic diisocyanate compounds such as anate, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate, 1,4-naphthalene diisocyanate; burette type adducts of these aromatic diisocyanates, isocyan Nurate ring adducts; hydrogenated MDI and derivatives of hydrogenated MDI; isocyanates at the hydroxyl groups of polyols such as ethylene glycol, propylene glycol, 1,4-butylene glycol, dimethylolpropionic acid, polyalkylene glycol, trimethylolpropane, hexanetriol Urethane adducts obtained by reacting polyisocyanate compounds in an excess ratio of groups; burette type adducts of these urethanized adducts, isocyanurates Adducts and the like. Among these, a burette type adduct or an isocyanurate cycloadduct of aliphatic polyisocyanate can be preferably used from the viewpoint of the touch and chemical resistance of the resulting coating film.

  The amount of the polyisocyanate compound (D) used is such that the isocyanate group (NCO) contained therein has a hydroxyl group (OH) in the hydroxyl group-containing acrylic resin (A) and hydroxyl group-containing polyester resin (B). It is appropriate that the equivalent ratio of NCO / OH is selected so that it is usually in the range of 0.5 to 2.0, preferably 0.8 to 1.5.

  In the coating composition of the present invention, if necessary, addition of a coloring pigment, extender pigment, curing catalyst, organic solvent, ultraviolet absorber, light stabilizer, antioxidant, surface conditioner, pigment dispersant, etc. The agents can be combined with the main agent and / or polyisocyanate curing agent in an appropriate combination.

  Color pigments include white pigments such as titanium oxide; black pigments such as carbon black, acetylene black, lamp black, bone black, graphite, iron black, aniline black; yellow iron oxide, titanium yellow, monoazo yellow, condensed azo yellow, Yellow pigments such as azomethine yellow, bismuth vanadate, benzimidazolone, isoindolinone, isoindoline, quinophthalone, benzidine yellow, permanent yellow; orange pigments such as permanent orange; red iron oxide, naphthol AS azo red, ansanthrone, anthra Red pigments such as quinonyl red, perylene maroon, quinacridone red pigment, diketopyrrolopyrrole, watching red, permanent red; cobalt purple, quinacridone violet, dioxazine bio Tsu bets like purple pigments; cobalt blue, phthalocyanine blue, blue pigments such as vat blue; etc. green pigment such as phthalocyanine green and the like.

  When the above-mentioned color pigment is used, the content thereof is suitably 1 to 60% by mass, preferably 2 to 50% by mass, based on the total solid content in the main agent.

  Examples of extender pigments include barita powder, precipitated barium sulfate, barium carbonate, calcium carbonate, gypsum, clay, silica, white carbon, diatomaceous earth, talc, magnesium carbonate, alumina white, gloss white, and mica powder.

  When the extender pigment is used, the content thereof is suitably in the range of 1 to 60% by mass, preferably 2 to 50% by mass based on the total solid content in the main agent.

  Examples of the curing catalyst include tin octylate, dibutyltin di (2-ethylhexanoate), dioctyltin di (2-ethylhexanoate), dioctyltin diacetate, dibutyltin dilaurate, dibutyltin oxide, and dioctyltin. Organometallic compounds such as oxide, dibutyltin fatty acid salt, lead 2-ethylhexanoate, zinc octylate, zinc naphthenate, fatty acid zinc, cobalt naphthenate, calcium octylate, copper naphthenate, tetra (2-ethylhexyl) titanate 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. The amount of the curing catalyst used is usually in the range of 0.001 to 2 parts by mass, preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the resin solid content in the coating composition.

  The organic solvent is not particularly limited, and conventionally known paint solvents such as hydrocarbon-based, ester-based, ether-based, alcohol-based, and ketone-based solvents can be used.

  The coating composition of the present invention is provided as a two-component paint comprising a main component containing a hydroxyl group-containing acrylic resin (A), a hydroxyl group-containing polyester resin (B) and resin beads (C), and a polyisocyanate curing agent, It is mixed immediately before use, and the viscosity is adjusted with an organic solvent as required, and then used for coating.

  In the present invention, a coated article can be obtained by coating the base material surface with the coating composition. The substrate is not particularly limited. For example, a polyolefin resin typified by polyethylene, polypropylene, etc .; polyethylene terephthalate resin, polybutylene terephthalate (PBT) resin, polycarbonate (PC) resin, polycarbonate-polybutylene terephthalate ( PC / PBT) thermoplastic polyester resins; acrylonitrile-styrene resins, acrylonitrile-butadiene-styrene (ABS) resins, styrene resins such as acrylonitrile-styrene-acrylate (ASA) resins; other polymethyl methacrylate resins, acrylic resins , Vinylidene chloride, polyamide resin, polyphenylene ether resin, polyoxymethylene resin, polyurethane resin, epoxy resin, etc. or their hybrids Plastics such as de resin and fiber reinforced plastic (Fiber-Reinforced Plastics), more can be mentioned metal or ceramic. These material surfaces may be appropriately subjected to degreasing treatment or surface treatment as necessary. Furthermore, after forming the undercoat film on the substrate surface, the coating composition of the present invention may be applied.

  The method for applying the coating composition of the present invention is not particularly limited. For example, it can be applied by air spray, airless spray, rotary atomizing coater, dip coating, brush or the like.

  The coating film by the coating composition of this invention can be normally 3-100 micrometers in cured film thickness, Preferably it can be in the range of 3-50 micrometers.

  Although the heating conditions in the coating-film formation method of the coating composition of this invention are not specifically limited, It can carry out by hold | maintaining for 10 to 90 minutes at 50-100 degreeC, Preferably 50-90 degreeC. When the plastic material is deformed by heat, for example, when an ABS resin or the like is used, the heating condition is preferably maintained at 50 to 80 ° C. for 10 to 90 minutes.

  The coating film obtained by the coating composition of the present invention obtained as described above is desirable because the soft feel value of the cured coating film having a thickness of 40 μm is in the range of 0 to 1.0 from the point of silky smoothness. In this specification, the soft feel value is a numerical value capable of quantifying a texture that feels soft when the coating film is touched like a fingertip. Specifically, the soft feel value means a value obtained by calculation from various measured values according to the following formula.

SF value = 0.13 [2.34 (log (MIU + MMD) −2.73) +0.03 [−0.91 log (Ra × MMD) −1.55] +0.11 [−6.36 logq max−3. 55] +0.68 [−1.11 log HU + 1.61]
Where SF value is an abbreviation for soft feel value, and MIU, MMD, Ra, q max and HU are the friction coefficient, friction coefficient average deviation, arithmetic average roughness, surface differential heat, and universal hardness, respectively. Means. The friction coefficient MIU and the friction coefficient average deviation MMD are values obtained from the surface friction resistance value measured using a friction tester KES-SE (trade name, manufactured by Kato Tech Co., Ltd.). The surface differential heat q max is a value measured by a precise rapid thermophysical property measuring apparatus KES-F7 (trade name, manufactured by Kato Tech Co., Ltd.). The arithmetic average roughness Ra is a value measured by a surface roughness meter SURFCOM 101 (trade name, manufactured by Tokyo Seimitsu Co., Ltd.). The universal hardness HU is a value measured by a hardness meter FISHCHER H100 (trade name, manufactured by Fisher Instruments).

  The method for measuring the soft feel value is disclosed in “Kazumi Yasuda et al., Quantitative Evaluation of Texture in Paint, Coating Engineering Vol. 36, No. 2, p. 40 (2001)”.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further in detail, this invention is not limited only to these Examples. Note that “part” and “%” indicate “part by mass” and “% by mass”, respectively, unless otherwise specified.

Production and production example 1 of hydroxyl group-containing acrylic resin (A) solution
A reaction vessel equipped with a stirrer, thermometer, reflux condenser, thermostat and dropping pump was charged with 60 parts of propylene glycol monomethyl ether acetate and heated to 145 ° C. with stirring while blowing nitrogen gas. A mixture of a monomer and a polymerization initiator consisting of 50.0 parts of ethyl-hexyl acrylate, 50.0 parts of 4-hydroxy-butyl acrylate, and 2.0 parts of 2,2′-azobis (2-methylbutyronitrile) is reacted. The solution was dropped into the vessel at a constant rate over 3 hours using a dropping pump. Thereafter, a mixture of 0.5 part of 2,2′-azobis (2-methylbutyronitrile) and 10 parts of propylene glycol monomethyl ether acetate was added dropwise over 1 hour. After completion of the dropwise addition, the reaction was terminated by aging for 3 hours at the same temperature. The obtained acrylic resin (A-1) solution was a uniform transparent solution having a solid content of 60%. The acrylic resin had a weight average molecular weight of about 20,000, a hydroxyl value of 195 mg KOH / g, and a glass transition temperature of -57 ° C.

Production Examples 2-7
In the said manufacture example 1, the same operation as manufacture example 1 is performed except making the mixture of a monomer and a polymerization initiator into the composition shown in Table 1, and acrylic resin (A-2)-(A -7) A solution was obtained. Table 1 shows the weight average molecular weight, hydroxyl value, and glass transition temperature of each acrylic resin obtained.
(Note 1) “Cardura E10P”: Japan Epoxy Resin, trade name, neodecanoic acid monoglycidyl ester (Note 2) “Acryester SL”: Mitsubishi Rayon, trade name, hydrocarbon group having 12 and 13 carbon atoms A methacrylate mixture having

Production Example 8 of Hydroxyl-Containing Polyester Resin (B) Solution 8
In a reaction vessel equipped with a stirrer, thermometer, rectification column and water separator, 134.8 parts of hexahydrophthalic anhydride, 82.4 parts of 1,6-hexanediol, 3.1 parts of neopentyl glycol, and isocyanuric 71.3 parts of acid tris (2-hydroxyethyl) was charged and heated to 140 ° C. in a nitrogen atmosphere.

  Then, it heated up to 200 degreeC over 1.5 hours, and it was made to react under reflux, adding xylene and distilling water off. After cooling when the desired acid value was reached, it was diluted with butyl acetate to obtain a polyester resin (B-1) solution having a solid content of 50%. The number average molecular weight of this polyester resin (B-1) was 2,200, and the hydroxyl value was 106 mgKOH / g.

Production Example 9
In a reaction vessel equipped with a stirrer, thermometer, rectification column and water separator, 69.3 parts of hexahydrophthalic anhydride, 73.0 parts of adipic acid, 106.2 parts of 1,6-hexanediol, and isocyanuric acid 26.1 parts of tris (2-hydroxyethyl) was charged and heated to 140 ° C. in a nitrogen atmosphere.

  Then, it heated up to 200 degreeC over 1.5 hours, and it was made to react under reflux, adding xylene and distilling water off. After cooling to the desired acid value, the solution was cooled and then diluted with butyl acetate to obtain a polyester resin (B-2) solution having a solid content of 50%. The number average molecular weight of this polyester resin (B-2) was 3,200, and the hydroxyl value was 55 mgKOH / g.

Production Example 10
In a reaction vessel equipped with a stirrer, thermometer, rectifying column and water separator, 69.3 parts of hexahydrophthalic anhydride, 73.0 parts of adipic acid, 106.2 parts of 1,6-hexanediol, and trimethylol 13.4 parts of propane was charged and heated to 140 ° C. in a nitrogen atmosphere.

  Then, it heated up to 200 degreeC over 1.5 hours, and it was made to react under reflux, adding xylene and distilling water off. When the desired acid value was reached, the mixture was cooled and then diluted with butyl acetate to obtain a polyester resin (B-3) solution having a solid content of 50%. The number average molecular weight of this polyester resin (B-3) was 3,000, and the hydroxyl value was 55 mgKOH / g.

Production Example 11
In a reaction vessel equipped with a stirrer, thermometer, rectifying column and water separator, 134.8 parts hexahydrophthalic anhydride, 82.4 parts 1,6-hexanediol, 3.1 parts neopentyl glycol, 36.6 parts of methylolpropane was charged and the temperature was raised to 140 ° C. in a nitrogen atmosphere.

  Then, it heated up to 200 degreeC over 1.5 hours, and it was made to react under reflux, adding xylene and distilling water off. When the desired acid value was reached, the mixture was cooled and then diluted with butyl acetate to obtain a polyester resin (B-4) solution having a solid content of 50%. The number average molecular weight of this polyester resin (B-4) was 2,200, and the hydroxyl value was 106 mgKOH / g.

Production Examples 1-19 and Comparative Examples 1-5 of Coating Composition
In accordance with the composition shown in Table 2, after dispersing the carbon black by a known dispersion method with the polyester resin (B) and the dispersant, the remaining components are blended in a container, mixed and stirred to a solid content of about 40%. Each main ingredient was made. A polyisocyanate curing agent was added to this main ingredient according to the composition shown in Table 2, and mixed uniformly to prepare each coating composition No. 1 to 24, and a viscosity of 25 seconds / Ford Cup # 4/20 with a diluent solvent. Viscous to ℃. Table 2 shows the solid content, and (Note 3) to (Note 11) in Table 2 are as follows.

(Note 3) Urethane resin beads (C-1): manufactured by Dainichi Seika Kogyo Co., Ltd., “RHU-5070D”, average particle diameter 7 μm
(Note 4) Urethane resin beads (C-2): manufactured by Negami Kogyo Co., Ltd., “P-800T”, average particle diameter 6 μm
(Note 5) Acrylic resin beads (C-3): “AFX-8” manufactured by Sekisui Plastics Co., Ltd., average particle size: 8 μm
(Note 6) Hollow foamed resin particles (C-4): “461-20” manufactured by EXPANCEL, average particle diameter: 8 μm
(Note 7) Cross-linked rubber particles (C-5): D.I. O. “Deogrip Micro S” manufactured by G company, average particle size 10 μm
(Note 8) Dispersant: Lubrizol Corporation, “Solspers 37500”
(Note 9) Curing catalyst: “Neostan U-100” manufactured by Nitto Kasei Co., Ltd.
(Note 10) Polyisocyanate (D-1): Asahi Kasei Chemicals, “Duranate 24A-90E”, Burette body (Note 11) Polyisocyanate (D-2): Sumitomo Bayer Urethane, “Sumidule N3300”, Nurate body.

Preparation of test coating plate Subsequently, the ABS plate (degreased) was air-sprayed with each coating composition No. 1 to 24 having a viscosity adjusted as described above so that the cured film thickness was about 40 μm, and 30 ° C. at 30 ° C. Each test coating plate was obtained by heating and curing for minutes.

Each obtained test coating board was used for the following performance test. The results are also shown in Table 2.
(* 1) Pencil hardness: Measured according to JIS K 5600-5-4. A pencil lead is applied at an angle of about 45 ° to the coating surface of each test coating plate, and the pencil is moved forward at a uniform speed by about 10 mm while pressing firmly against the coating surface to such an extent that the core does not break. This operation was repeated 5 times at different locations, and the hardness symbol of the hardest pencil that did not leave a pencil lead mark on the coating film was defined as pencil hardness.
(* 2) Adhesion: Make a cut line with a cutter so that it reaches the substrate surface of each test coating plate, make 100 squares of 2mm x 2mm size, and stick adhesive cellophane tape on the surface. The number of residual coatings in the squares after peeling it off rapidly at 20 ° C. was examined. The case where no peeling occurred was marked with ○, and the case where one square or more was peeled off was marked with ×.
(* 3) Moist feeling: In order to evaluate the touch feeling of the coating surface of each test coating plate, the moist feeling when touched with a finger was evaluated according to the following criteria.
○: When the cured coating film is touched by hand, it has elasticity Δ: When the cured coating film is touched by hand, it is slightly elastic ×: When the cured coating film is touched by hand, there is almost no elasticity .
(* 4) Soft feel value (SF value): The soft feel value (SF value) of the coating film of each test coating plate was measured according to the above-described calculation formula.
(* 5) Chemical resistance: A chemical (COPATONE SPF50) was dropped on the coating surface of each test coating plate, spread and left at 50 ° C for 3 hours, and then the surface chemical was wiped off. ) Pencil hardness and (* 2) adhesion were evaluated.
Appearance of coating film ○: No abnormality ×: Itchy, discolored, with marks, etc.

The present invention relates to parts related to electrical and electronic equipment such as PC casings, automobile interior parts such as instrument panels, center consoles, dashboards and door trims, chair parts, armrests, handrails, window frames, door knobs and other life related parts. The present invention is industrially useful because it can provide a coating composition applicable to plastic products and metal products in applications such as furniture and building material-related parts.

Claims (4)

A coating composition comprising a main component containing a hydroxyl group-containing acrylic resin (A), a hydroxyl group-containing polyester resin (B) and resin beads (C), and a polyisocyanate curing agent,
The hydroxyl group-containing acrylic resin (A) contains a hydroxyl group-containing acrylic resin (A1) having a hydroxyl value of 100 to 250 mgKOH / g, a weight average molecular weight of 5,000 to 50,000, and a glass transition temperature of −25 ° C. or less.
A coating composition comprising 20 to 80% by mass of resin beads (B) based on the total solid content in the main agent.   The coating composition according to claim 1, wherein the hydroxyl group-containing polyester resin (B) comprises a hydroxyl group-containing polyester resin (B1) having a hydroxyl value of 50 to 200 mgKOH / g and a number average molecular weight of 2,000 to 20,000.   The hydroxyl group-containing polyester resin (B1-1) obtained by a reaction between a polyhydric alcohol containing a cyclic polyol compound (b1) having a nurate structure and a polybasic acid is used as the hydroxyl group-containing polyester resin (B1). Paint composition. A coated article obtained by coating the base material surface with the coating composition according to any one of claims 1 to 3.