WO2020067459A1

WO2020067459A1 - Coating material composition, method for forming coating film, and coated article

Info

Publication number: WO2020067459A1
Application number: PCT/JP2019/038236
Authority: WO
Inventors: 弘二吉川; 橋本　学; 了中谷
Original assignee: 大日本塗料株式会社
Priority date: 2018-09-28
Filing date: 2019-09-27
Publication date: 2020-04-02
Also published as: JP2020055900A; JP6977226B2; CN112703232A

Abstract

The present invention relates to: a coating material composition containing acrylic polyol (A), polyether polyol (B) having a number-average molecular weight of 1,000 or less and a hydroxyl value exceeding 100 mgKOH/g, and a polyisocyanate compound (C); a method for forming a coating film using this coating material composition; and a coated article.

Description

Coating composition, coating film forming method, and coated body

The present invention relates to a coating composition, particularly to a coating composition capable of forming a coating film having excellent lactic acid resistance and oleic acid resistance, a method for forming a coating film using the coating composition, and a coated body.

内装 Plastic materials such as polycarbonate resin and acrylonitrile-butadiene-styrene (ABS) resin are often used for automotive interior parts (eg, instrument panel, center console, dashboard, door trim, etc.). These interior parts have excellent design properties such as finish and glossiness, and also have resistance to fingerprints and sweat (lactic acid resistance and oleic acid resistance) due to contact with human hands and skin. It is also required. Therefore, a coating composition capable of forming a coating film having lactic acid resistance and oleic acid resistance has been desired.

Patent Document 1 discloses a hydroxyl group-containing resin and a coloring component as a coating film forming method capable of forming a multi-layer coating film having excellent adhesion, sweat resistance (oleic acid resistance and lactic acid resistance) and excellent finish on an object to be coated. To form a base coating film by applying a colored base coating composition containing the following to the substrate, and then having a weight average molecular weight of 3,000 to 20,000 and a hydroxyl value within the range of 100 to 200 mg KOH / g. Hydroxyl-containing acrylic resin (A), polyisocyanate compound (C), curing catalyst (D), and a surface conditioner containing silicon-based surface conditioner (E-1) and acrylic-based surface conditioner (E-2) as essential components A clear coating composition containing (E) and having a glass transition temperature of 90 ° C. or more when cured under specific conditions and a molecular weight between crosslinks of the cured coating of 900 g / mol or less is applied. Shit Method for forming a coating film comprising forming a yer coating is disclosed. Patent Literature 2 discloses a weight-average plastic coating composition which can provide a coating film having excellent adhesion to a plastic material, stain resistance (oleic acid resistance and lactic acid resistance) and finish even with one coat. A hydroxyl group-containing acrylic resin (A) having a molecular weight of 3,000 to 20,000 and a hydroxyl value in the range of 100 to 200 mgKOH / g, a polyisocyanate compound (B), a curing catalyst (C), and a silicon-based surface conditioner ( D-1) and a surface conditioner (D) having an acrylic surface conditioner (D-2) as an essential component, and the glass transition temperature of the cured coating film when cured under specific conditions is 100 ° C. or higher, A coating composition for plastics in which the cured coating has a molecular weight between crosslinks of 900 g / mol or less is disclosed.

Patent Document 3 discloses a coating composition that forms a coating film having excellent car wash resistance, acid resistance, and weather resistance, has a hydroxyl value of 80 to 220 mgKOH / g, a glass transition temperature of -50 ° C or higher, and 0 ° C. A hydroxyl group-containing resin (A) containing a unit derived from 4-hydroxybutyl (meth) acrylate in an amount of 25 to 55% by mass, a hydroxyl value of 80 to 220 mgKOH / g and a glass transition temperature of 0 There is disclosed a coating composition comprising, as essential components, a hydroxyl group-containing resin (B) at a temperature of ５０50 ° C. and a crosslinking agent (C) comprising a polyisocyanate compound.

However, the coating compositions described in Patent Documents 1 to 3 do not always have sufficient lactic acid resistance, and when applied to the surface of a glittering coating film containing a glittering pigment, such as a metal-like coating film, a fingerprint is produced.・ If sweat or the like touches for a long time, discoloration of the glittering coating film tends to be conspicuous.

JP-A-2015-66543 JP 2014-19714 A JP 2009-46642 A

The present invention has an adhesive property to an object to be coated, has no tackiness (stickiness), and is excellent in oleic acid resistance and lactic acid resistance. It is an object of the present invention to provide a coating composition capable of suppressing discoloration over a long period of time even when applied to the surface of a glitter coating film containing a glitter pigment. Another object of the present invention is to provide a method for forming a coating film using the coating composition, and a coated body.

The present invention relates to the following items.
[1] An acrylic polyol (A), a polyether polyol (B) having a number average molecular weight of 1,000 or less and a hydroxyl value exceeding 100 mgKOH / g, and a polyisocyanate compound (C). Paint composition.
[2] The above item [1], wherein the polyether polyol (B) is a polyether polyol (B) having a number average molecular weight of 100 to 1000 and a hydroxyl value of 200 to 700 mgKOH / g. ] The coating composition as described in [1].
[3] The coating composition according to item [1] or [2], wherein the acrylic polyol (A) is an acrylic polyol (A) having a hydroxyl value of 50 to 200 mgKOH / g.
[4] The content of the above items [1] to [3], wherein the content ratio of the acrylic polyol (A) and the polyether polyol (B) is 50/50 to 90/10 (mass ratio). The coating composition according to any one of the above.
[5] The coating composition according to any of the above items [1] to [4], further comprising a silicon-based surface conditioner (D).
[6] A step of applying the coating composition according to any one of the above items [1] to [5] to an object to be coated, and curing the coating composition applied to the object to form a coating film. And a step of forming a coating film.
[7] The method for forming a coating film according to the above item [6], wherein the object to be coated has a glitter coating film containing a glitter pigment formed on a surface.
[8] The above item [6] or [7], wherein the object to be coated is a resin base material or a resin base material having a glitter coating film containing a glitter pigment formed on the surface. 3. The method for forming a coating film according to item 1.
[9] A coated body having a coating film formed by curing the coating composition according to any one of [1] to [5].

ADVANTAGE OF THE INVENTION According to this invention, it has adhesiveness with a to-be-coated material, has no tackiness (stickiness), and also can form a coating film excellent in oleic acid resistance and lactic acid resistance. Even when applied to the surface of a glittering coating film containing a glittering pigment, a coating composition capable of suppressing discoloration for a long period of time can be provided. According to the present invention, it is also possible to provide a method for forming a coating film using the coating composition, and a coated body.

The coating composition of the present invention contains, in addition to the acrylic polyol (A) and the polyisocyanate compound (C), a polyether polyol (B) having a number average molecular weight of 1,000 or less and a hydroxyl value exceeding 100 mgKOH / g. . By adding such a polyether polyol (B) having a relatively low number average molecular weight and a relatively high hydroxyl value, a coating film (cured film) obtained from the acrylic polyol (A) and the polyisocyanate compound (C) ) Has excellent properties, that is, while maintaining the adhesion to the object to be coated, a tacky feeling, and oleic acid resistance, the crosslink density of the obtained coating film is increased, and the penetration of lactic acid into the coating film is suppressed. Lactic acid resistance can be improved. As a result, by using the coating composition of the present invention, it is possible to form a coating film having adhesiveness to an object to be coated, having no tackiness, and having excellent oleic acid resistance and excellent lactic acid resistance. be able to.

The coating film (cured film) obtained from the coating composition of the present invention is excellent not only in oleic acid resistance but also in lactic acid resistance, and is excellent in resistance to fingerprints, sweat and the like. Even when applied to the surface of a glittering coating film containing a glittering pigment, the discoloration can be suppressed for a long period of time.

The coating composition of the present invention contains an acrylic polyol (A), a polyether polyol (B) having a number average molecular weight of 1,000 or less and a hydroxyl value exceeding 100 mgKOH / g, and a polyisocyanate compound (C). It is a thing.

The “hydroxyl value” in the present invention is the number of mg of potassium hydroxide required to completely acetylate the hydroxyl group in 1 g of a sample with acetic anhydride and then neutralize it. The “number average molecular weight” in the present invention is a number average molecular weight in terms of standard polystyrene measured by a GPC method (gel permeation chromatography).

The acrylic polyol (A) used in the present invention is not particularly limited, but usually has a hydroxyl value of preferably 50 to 200 mgKOH / g, more preferably 75 to 150 mgKOH / g. When the hydroxyl value of the acrylic polyol (A) is within this range, a coating film having more excellent properties can be obtained.

アクリル Although the acrylic polyol (A) is not particularly limited, it is usually preferable that the number average molecular weight is 1500 to 15,000 from the viewpoint of the properties of the obtained coating film.

The acrylic polyol (A) is a hydroxyl group-containing (meth) acrylic polymer (acrylic polymer or methacrylic polymer). For example, one or more hydroxyl group-containing (meth) acrylate monomers and a hydroxyl group-free (meth) Copolymers with one or more acrylate monomers are included. If necessary, another polymerizable unsaturated monomer may be copolymerized. Here, (meth) acrylate means acrylate or methacrylate.

The hydroxyl group-containing (meth) acrylate monomer is not particularly limited, but includes, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl Monoesters of (meth) acrylic acid such as (meth) acrylate and a dihydric alcohol, and (meth) acrylates having a polyoxyethylene chain whose molecular terminal is a hydroxyl group are exemplified.

The (meth) acrylate monomer not containing a hydroxyl group is not particularly limited, but includes, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and n-butyl (meth) acrylate. ) Acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, dodecyl (meth) A) alkyl or cycloalkyl (meth) acrylate such as acrylate, tridecyl (meth) acrylate, octadecyl (meth) acrylate, cyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate , Isobornyl (meth) acrylate, adamantyl (meth) acrylate, allyl (meth) acrylate, 1,6-hexanediol di (meth) acrylate, glycidyl (meth) acrylate.

The other polymerizable unsaturated monomer which may be copolymerized is not particularly limited, but examples thereof include a vinyl group-containing aromatic compound such as styrene, α-methylstyrene and vinyl toluene, and a vinyl group-containing compound such as vinyl acetate. , (Meth) acrylic acid and the like.

市販 As the acrylic polyol (A), a commercially available product may be used. Examples of commercially available products include the Acridic (registered trademark) series of DIC Corporation, and the Acryset (registered trademark) series of Nippon Shokubai Co., Ltd.

The acrylic polyol (A) may be used alone or in combination of two or more.

ポリ The polyether polyol (B) used in the present invention has a number average molecular weight of 1,000 or less and a hydroxyl value of more than 100 mgKOH / g.

数 The number average molecular weight of the polyether polyol (B) is 1,000 or less, preferably 800 or less, more preferably 700 or less. When the number average molecular weight of the polyether polyol (B) is 1,000 or less, preferably 800 or less, the compatibility of the polyether polyol (B) with the acrylic polyol (A) is good, and a coating film having excellent properties is obtained. Obtainable. Although the lower limit of the number average molecular weight of the polyether polyol (B) is not particularly limited, it is usually preferably 100 or more.

The hydroxyl value of the polyether polyol (B) is more than 100 mgKOH / g, preferably 200 mgKOH / g or more, more preferably 230 mgKOH / g or more. In one embodiment, the hydroxyl value of the polyether polyol (B) is preferably 250 mgKOH / g or more, and particularly preferably 300 mgKOH / g or more. When the hydroxyl value of the polyether polyol (B) is more than 100 mgKOH / g, preferably 200 mgKOH / g or more, and more preferably 230 mgKOH / g or more, the crosslink density of the resulting coating film can be sufficiently increased, and excellent lactic acid resistance can be obtained. A coating film having properties can be obtained. Although the upper limit of the hydroxyl value of the polyether polyol (B) is not particularly limited, it is usually preferably 700 mgKOH / g or less.

Examples of the polyether polyol (B) include, but are not particularly limited to, propylene glycol, ethylene glycol, glycerin, trimethylolpropane, aliphatic diamines such as triethanolamine, pentaerythritol, and ethylenediamine; aromatic diamines, sorbitol, Polymers obtained by addition polymerization of one or more polyfunctional alcohols or amines such as sucrose) with one or more alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran.

市販 A commercially available polyether polyol (B) may be used. Examples of commercially available products include Sannics PP200, PP400, PP600, PP950, PP1000, GP250, GP400, GP600, GP700, GP1000, TP400, AP470, EP900, SP750, etc., manufactured by Sanyo Chemical Industries, Ltd.

The polyether polyol (B) may be used alone or in combination of two or more.

In the coating composition of the present invention, the content ratio of the acrylic polyol (A) and the polyether polyol (B) is not particularly limited, and the content of the acrylic polyol (A) and the type of the polyether polyol (B) may be different. However, it is usually preferably 50/50 to 90/10 (mass ratio), more preferably 60/40 to 88/12 (mass ratio). If the ratio of the polyether polyol (B) to the total amount of the acrylic polyol (A) and the polyether polyol (B) is less than 10% by mass, the effect of improving lactic acid resistance may not be sufficiently obtained. is there. If the ratio of the polyether polyol (B) to the total amount of the acrylic polyol (A) and the polyether polyol (B) is more than 50% by mass, the resulting coating film may have poor tackiness, appearance, and the like. There is.

The coating composition of the present invention may be any other hydroxyl group-containing compound which reacts with an isocyanate group of the polyisocyanate compound (C) to form a urethane bond, such as a polyester polyol or polycarbonate, as long as the effects of the present invention are not impaired. It may further contain a polyol or the like. Usually, the content is preferably 15% by mass or less based on the total amount of the hydroxyl group-containing compound including the acrylic polyol (A) and the polyether polyol (B).

The polyisocyanate compound (C) used in the present invention is a compound having two or more isocyanate groups in one molecule, and is not particularly limited. For example, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, 2,6 Aliphatic diisocyanates such as diisocyanatomethylcaproate; 1,3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate; -Isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,4-bis ( Alicyclic diisocyanates such as isocyanatomethyl) cyclohexane and 1,3-bis (isocyanatomethyl) cyclohexane; m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4- or 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, dianisidine diisocyanate, 4,4'-diif Aromatic diisocyanates such as nyl ether diisocyanate; 1,3- or 1,4-xylylene diisocyanate, ω, ω'-diisocyanate-1,4-diethylbenzene, 1,3- or 1,4-bis (α, α- Aromatic diisocyanates such as dimethylisocyanatomethyl) benzene; triphenylmethane-4,4 ', 4' '-triisocyanate, 1,3,5-triisocyanatebenzene, 2,4,6-triisocyanatetoluene and the like Triisocyanate; tetraisocyanate such as 4,4'-diphenyldimethylmethane-2,2 ', 5,5'-tetraisocyanate; polymerized polyisocyanate such as dimer or trimer of tolylene diisocyanate and polyphenylpolymethylene And polyisocyanates. Of these, aliphatic diisocyanates and alicyclic diisocyanates are preferred from the viewpoint of the properties of the obtained coating film, and particularly from the viewpoint that the coating film is unlikely to yellow.

市販 A commercially available polyisocyanate compound (C) may be used. Examples of commercially available products include the Vernock (registered trademark) series of DIC Corporation, the Duranate (registered trademark) series of Asahi Kasei Chemicals Corporation, and the Sumidur (registered trademark) series of Sumika Covest Low Urethane Co., Ltd.

As the polyisocyanate compound (C), one type may be used alone, or two or more types may be used in combination.

In the coating composition of the present invention, the content of the polyisocyanate compound (C) is not particularly limited, but is usually the hydroxyl group in the hydroxyl group-containing compound containing the acrylic polyol (A) and the polyether polyol (B). The molar ratio of the amount of isocyanate groups in the polyisocyanate compound (C) to the amount of (NCO mol% / OH mol%) is preferably 0.8 to 1.5, and 0.9 to 1.3. Is more preferable. When the content of the polyisocyanate compound (C) is within this range, the amount of unreacted hydroxyl groups and isocyanate groups decreases, so that a coating film having more excellent properties can be obtained.

塗料 The coating composition of the present invention preferably further contains a silicon-based surface conditioner (D). By adding the silicon-based surface conditioner (D), the contact angle of lactic acid on the coating film surface can be reduced, the penetration of lactic acid into the coating film can be further suppressed, and the lactic acid resistance can be further improved.

The silicon-based surface conditioner (D) used in the present invention is not particularly limited, and examples thereof include organopolysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, and methylalkylpolysiloxane, and modified poly obtained by modifying organopolysiloxane. Siloxane, for example, polyether-modified polysiloxane such as polyether-modified dimethylpolysiloxane; polyester-modified polysiloxane such as polyester-modified dimethylpolysiloxane; polyester-modified methylalkylpolysiloxane; aralkyl-modified polysiloxane such as aralkyl-modified methylalkylpolysiloxane; Is mentioned. Polyether-modified (meth) acryloyl group-containing dimethylpolysiloxane, polyester-modified (meth) acryloyl group-containing dimethylpolysiloxane and the like are also included.

市販 A commercially available silicon-based surface conditioner (D) may be used. Commercially available products include, for example, DC11PA, ST80PA, DC3074, DC3037, SR2402 manufactured by Dow Corning Toray Co., Ltd .; KP-321, KP-324, KP-327, KR-9218, X-40- manufactured by Shin-Etsu Chemical Co., Ltd. 9220; TSR165, XR-31B1763 manufactured by Toshiba Silicone Co., Ltd .; BYK-341, BYK-344, BYK-306, BYK-307, BYK-325, BYK-315, BYK-320, BYK-322 manufactured by BYK Japan KK , BYK-323, BYK-300, BYK-302, BYK-330, BYK-333, BYK-335, BYK-370, BYK-SILCLEAN 3700; DISPARLON 1711, 1751N, 1761, LS-0 manufactured by Kusumoto Kasei Co., Ltd. 1, LS-050; manufactured by Kyoeisha Chemical Co., Ltd. POLYFLOW KL-400HF, KL-401, KL-402, KL-403, KL-404, and the like.

The silicon-based surface conditioner (D) generally has a weight average molecular weight of preferably from 1,000 to 120,000, and more preferably from 8,000 to 15,000, in view of compatibility and properties of the obtained coating film. More preferably, there is.

As the silicon-based surface conditioner (D), one type may be used alone, or two or more types may be used in combination.

In the coating composition of the present invention, the content of the silicone-based surface conditioner (D) is not particularly limited, but usually, the hydroxyl group-containing compound 100 containing the acrylic polyol (A) and the polyether polyol (B) is used. The amount is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass with respect to parts by mass.

The coating composition of the present invention may contain, in addition to or in place of the silicon-based surface conditioner (D), other surface-conditioning agents such as an acrylic surface conditioner, silicone Modified acrylic surface conditioners, fluorine surface conditioners, vinyl surface conditioners, and the like can also be included.

塗料 The coating composition of the present invention generally preferably contains a solvent from the viewpoint of coating workability, and is preferably an organic solvent type coating composition.

溶剤 The solvent used in the present invention is not particularly limited, and may be appropriately selected from those commonly used in the field of paint. The solvent used is preferably one that can dissolve and compatibilize the resin in the coating composition. Examples of the solvent include aromatic hydrocarbons such as toluene and xylene, esters such as ethyl acetate, butyl acetate, isobutyl acetate, 2-ethylhexyl acetate, 3-methoxybutyl acetate and cyclohexyl acetate, methyl ethyl ketone and methyl isobutyl. Ketones, cyclohexanone, ketones such as isophorone, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, glycol ethers such as diethylene glycol monoethyl ether acetate, ethers, alcohols, glycols, Examples include acetates and mineral spirits.

The solvent may be used alone or in combination of two or more.

The content of the solvent in the coating composition of the present invention, in other words, the solid content in the coating composition is not particularly limited, and from the viewpoint of coating workability, may be appropriately selected so as to have an appropriate viscosity. it can.

If necessary, the coating composition of the present invention may contain various additives commonly used in other coating compositions, such as curing accelerators (for example, tin-based curing accelerator, amine-based curing accelerator, lead-based Curing accelerators), antioxidants (eg, phenolic antioxidants, hindered phenolic antioxidants, etc.), light stabilizers (eg, hindered amine light stabilizers, benzoate light stabilizers, etc.), ultraviolet absorption Agents (eg, benzotriazole-based UV absorber, triazine-based UV absorber, benzophenone-based UV absorber, etc.), coloring agents (eg, pigments, dyes), slip agents, and the like.

The coating composition of the present invention can be prepared by mixing the respective components, and even if it is a one-pack type coating composition, the main components [acrylic polyol (A), polyether polyol (B), solvent, etc.] And a curing agent [polyisocyanate compound (C)] at the time of coating.

塗料 The coating composition of the present invention can form a coating film, for example, by applying it to an object to be coated and curing it. The coated body of the present invention has a coating film formed by curing the coating composition of the present invention.

The coating (application) of the coating composition is not particularly limited, and can be performed by a known method, for example, spray coating (air spray coating, airless spray coating), dip coating, roll coater coating, or the like. .

硬化 The curing conditions of the coating composition are not particularly limited, either, and can be appropriately selected according to the components contained in the coating composition. For example, curing can be performed by holding the coating composition applied to the object to be coated at a temperature of 50 to 150 ° C. for 5 to 90 minutes and baking.

(4) After coating the coating composition of the present invention and before curing by heating, the coating composition applied to the object to be coated may be dried by leaving it for a predetermined time or performing preliminary heating as necessary.

The material to be coated with the coating composition of the present invention is not particularly limited in its material, for example, iron, aluminum, copper, brass, stainless steel, metal or alloy such as tin or galvanized steel, polyethylene resin, Polypropylene resin, polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polycarbonate (PC) resin, acrylonitrile-styrene (AS) resin, acrylonitrile-butadiene-styrene (ABS) resin, acrylonitrile-styrene-acrylate (ASA) Resins (plastics) such as resins, acrylic resins, polyamide resins, vinylidene chloride resins, polyphenylene ether resins, polyoxymethylene resins, polyurethane resins, and epoxy resins. In one embodiment, the substrate is preferably a resin substrate.

形状 The shape of the object to be coated is not particularly limited, and examples thereof include a film shape and a plate shape. Further, the shape is not limited to a planar shape, but may be a shape (formed body) processed two-dimensionally or three-dimensionally.

The object to be coated with the coating composition of the present invention may be one obtained by applying a base coating composition to a substrate and forming an undercoat film on the surface, if desired.

As described above, the coating film formed from the coating composition of the present invention is not only oleic acid-resistant, but also excellent in lactic acid resistance and excellent in resistance to fingerprints, sweat and the like. It can be particularly preferably applied to an object to be coated on which a glitter coating containing a glitter pigment is formed, for example, a resin substrate having a glitter coating containing a glitter pigment formed on the surface. it can.

光 The glittering coating film and other undercoating films can also be formed according to a known method.

膜厚 The thickness of the coating film (cured film) formed from the coating composition of the present invention is not particularly limited, and can be appropriately selected depending on the use and the like. The thickness of the coating film (cured film) of the present invention is, for example, preferably 1 to 100 μm, and more preferably 10 to 50 μm.

Hereinafter, the present invention will be described in more detail with reference to examples. Note that the present invention is not limited to these examples.

において In Examples and Comparative Examples, measurement and evaluation were performed by the following methods.

<Evaluation of tackiness (stickiness)>
The tackiness (stickiness) of the coating film was confirmed by touching with hands and evaluated according to the following criteria.
：: There is no tackiness (stickiness) at all.
Δ: Tackiness (stickiness) is present immediately after the coating film is dried, but the tackiness disappears after 2 hours.
×: Tackiness (stickiness) is observed immediately after the coating film is dried and also after 12 hours.

<Evaluation of adhesion to coated object>
The adhesion of the coating film to the substrate was measured by an adhesion tester manufactured by Elcometer. In addition, in accordance with JIS-K5600-5-6: 1999 "Adhesion (cross-cut method)", a grid-like cut is made in the coating at intervals of 2 mm, and the adhesion is evaluated by a tape peeling test. Was. Each criterion was set as follows.
：: Class 0 (the peeling rate of the coating film after evaluation is 0%)
Δ: Category 1 (peeling rate of coating film after evaluation is more than 0% to 5% or less)
×: Category 2 to 5 (peeling rate of coating film after evaluation exceeds 5%)

<Evaluation of lactic acid resistance>
After 72 hours from the formation of the coating film, 0.2 ml of a 10% by mass aqueous solution of lactic acid was dropped on the coating film and left at 80 ° C. for 24 hours. The appearance of the coating film was visually observed and evaluated according to the following criteria.
：: no swelling of the coating film. (Good)
×: Swelling of the coating film was observed. (Bad)

<Evaluation of oleic acid resistance>
72 hours after the formation of the coating film, 0.2 ml of a 10% by mass aqueous solution of oleic acid was dropped on the coating film and left at 80 ° C for 24 hours. The appearance of the coating film was visually observed and evaluated according to the following criteria.
：: no swelling of the coating film. (Good)
×: Swelling of the coating film was observed. (Bad)

<Example 1>
(Preparation of undercoat paint composition)
30 parts by mass of an acrylic polyol solution (WNL-200 manufactured by DIC Corporation, solid content concentration: 50% by mass, hydroxyl value of resin solids: 40 mg KOH / g, Tg: 60 ° C.), cellulose acetate butyrate solution (CAB381-20 manufactured by Eastman) Butyl acetate solution; solids concentration 10% by mass) 40 parts by mass, aluminum pigment dispersion (Toyo Aluminum Co., Ltd. aluminum paste BP-Z485, solids concentration 50% by mass) 4 parts by mass, higher fatty acid amide dispersant (Kyoeisha) An undercoat paint composition was prepared by uniformly mixing 2 parts by mass of FLOWNON HR-4AF manufactured by Chemical Co., Ltd. (solid content concentration: 20% by mass) and 24 parts by mass of butyl acetate (solvent).

(Preparation of Top Coating Composition 1)
74 parts by mass of an acrylic polyol solution (Acrydic AU-7002 manufactured by DIC Corporation, solid content concentration: 55% by mass, hydroxyl value of resin solids: 110 to 120 mgKOH / g), polyether polyol (Sannics manufactured by Sanyo Chemical Industry Co., Ltd.) TP400, 10 parts by mass of hydroxyl value of resin solids: 395 mgKOH / g, number average molecular weight: 400), 1 part by mass of silicon-based surface modifier (BYK331 manufactured by BYK Japan KK), hindered amine light stabilizer (BASF TINUVIN123) (TN123)) 1 part by mass, 1 part by mass of a triazine-based ultraviolet absorber (TINUVIN400 (TN400) manufactured by BASF), a lead-based curing accelerator (butyl acetate solution of TOS-TK-1 manufactured by Osaka Shinyaku Co., Ltd. 1% by mass)) 2 parts by mass, and butyl acetate ( Agent) 11 parts by weight were uniformly mixed to prepare a main agent of the coating composition.

To the prepared base material, 51.3 parts by mass of a polyisocyanate compound (MFA-75B manufactured by Asahi Kasei Chemicals Corporation, active ingredient: 75% by mass, NCO: 13.7% by mass) as a curing agent was added, mixed uniformly, and overcoated. Paint composition 1 was prepared. The molar ratio of the amount of isocyanate groups in the polyisocyanate compound to the amount of hydroxyl groups in the acrylic polyol and polyether polyol (NCO mole% / OH mole%) is 1.1.

(Formation of coating film)
The prepared undercoat paint composition was applied on an ABS base material using an air spray so as to have a dry film thickness of about 10 to 15 μm, and dried at 80 ° C. for 30 minutes to form an undercoat paint film. . This undercoat film is a glitter coating film containing a glitter pigment (aluminum pigment).

Next, on the undercoat film formed on the base material, the prepared topcoat paint composition 1 was applied using an air spray so that the dry film thickness was about 30 μm, and left at room temperature for 10 minutes. The coating was formed by drying at 80 ° C. for 30 minutes.

Then, the tackiness, adhesion to a substrate, lactic acid resistance, and oleic acid resistance of the formed coating film were evaluated by the above method. Table 1 shows the results.

<Examples 2 to 15, Comparative Example 1>
Overcoat compositions 2 to 16 were prepared in the same manner as in the preparation of the overcoat composition 1 of Example 1 except that the raw materials and the composition were changed as shown in Tables 1 and 2. The numerical values in Tables 1 and 2 are parts by mass. Then, a coating film was formed in the same manner as in Example 1 except that the prepared top coating compositions 2 to 16 were used instead of the top coating composition 1.

Then, the tackiness, adhesion to a substrate, lactic acid resistance, and oleic acid resistance of the formed coating film were evaluated by the above method. The results are shown in Tables 1 and 2.

原料 The raw materials for the topcoat composition are shown below.

[Acrylic polyol (A component)]
“Acrydic AU-7002” (manufactured by DIC Corporation, solid content 55% by mass, hydroxyl value of solid content (acrylic polyol): 110 to 120 mgKOH / g) (abbreviation in the table: AU-7002)
“Acrydic VU-191” (manufactured by DIC Corporation, solid content 55% by mass, hydroxyl value of solid content (acrylic polyol): 60 mgKOH / g) (abbreviation in table: VU-191)
“Acridic A859-B” (manufactured by DIC Corporation, solid content: 75% by mass, hydroxyl value of solid content (acrylic polyol): 137 mgKOH / g) (abbreviation in the table: A859-B)

[Polyether polyol (component B)]
"Sannicks TP400" (manufactured by Sanyo Chemical Industries, Ltd., resin component 100% by mass, number average molecular weight of resin component (polyether polyol): 400, hydroxyl value of resin component (polyether polyol): 395 mg KOH / g) (Table) (Abbreviation in the middle: TP400)
“Sunnics GP250” (manufactured by Sanyo Chemical Industries, Ltd., resin component 100% by mass, number average molecular weight of resin component (polyether polyol): 250, hydroxyl value of resin component (polyether polyol): 670 mg KOH / g) (Table) (Abbreviation in the middle: GP250)
“Sannicks GP700” (manufactured by Sanyo Chemical Industries, Ltd., resin component 100% by mass, number average molecular weight of resin component (polyether polyol): 700, hydroxyl value of resin component (polyether polyol): 240 mgKOH / g) (Table (Abbreviation in the middle: GP700)
"Sannicks PP400" (manufactured by Sanyo Chemical Industries, Ltd., resin component 100% by mass, number average molecular weight of resin component (polyether polyol): 400, hydroxyl value of resin component (polyether polyol): 280 mg KOH / g) (Table) (Abbreviation in the middle: PP400)

[Polyisocyanate compound (component C)]
"Duranate MFA-75B" (manufactured by Asahi Kasei Chemicals Corporation, isocyanurate-modified hexamethylene diisocyanate, NCO concentration 13.7% by mass, non-volatile content 75% by mass) (abbreviation in the table: MFA-75B)

[Other additives]
"BYK331" (manufactured by Big Chemie, silicon-based surface conditioner)
"TINUVIN123" (manufactured by BASF, hindered amine light stabilizer) (abbreviation in the table: TN123)
“TINUVIN400” (manufactured by BASF, hydroxyphenyltriazine (HPT) -based ultraviolet absorber) (abbreviation in the table: TN400)
"Lead-based curing accelerator" (curing catalyst, butyl acetate solution of TOS-TK-1 manufactured by Osaka Shinyaku Co., Ltd. (active ingredient: 0.1% by mass))

As is clear from Tables 1 and 2, excellent properties of a coating film obtained from an acrylic polyol and a polyisocyanate compound by adding a polyether polyol having a low number average molecular weight and a high hydroxyl value, that is, Lactic acid resistance can be improved while maintaining the adhesion to the object to be coated, a tacky feeling, and oleic acid resistance.

According to the present invention, there is provided a coating composition capable of forming a coating film having adhesion to an object to be coated, having no tackiness (stickiness), and being excellent in oleic acid resistance and lactic acid resistance. be able to. The coating composition of the present invention can form a coating film having not only oleic acid resistance but also excellent lactic acid resistance, such as a metallic coating film, even when applied on the surface of a glitter coating film containing a glitter pigment. The discoloration can be suppressed over a long period of time. The coating composition of the present invention can be suitably used for parts to be touched by human hands and skin, for example, interior parts of automobiles and exteriors of electric appliances such as mobile phones and audio equipment.

Claims

Acrylic polyol (A),
A polyether polyol (B) having a number average molecular weight of 1,000 or less and a hydroxyl value of more than 100 mgKOH / g;
A coating composition comprising a polyisocyanate compound (C).
The coating according to claim 1, wherein the polyether polyol (B) is a polyether polyol (B) having a number average molecular weight of 100 to 1000 and a hydroxyl value of 200 to 700 mgKOH / g. Composition.
塗料 The coating composition according to claim 1, wherein the acrylic polyol (A) is an acrylic polyol (A) having a hydroxyl value of 50 to 200 mgKOH / g.
The acrylic polyol (A) is an acrylic polyol (A) having a hydroxyl value of 50 to 200 mgKOH / g,
The coating according to claim 1, wherein the polyether polyol (B) is a polyether polyol (B) having a number average molecular weight of 100 to 1000 and a hydroxyl value of 200 to 700 mgKOH / g. Composition.
The coating composition according to any one of claims 1 to 4, wherein the content ratio of the acrylic polyol (A) and the polyether polyol (B) is 50/50 to 90/10 (mass ratio). Stuff.
The coating composition according to any one of claims 1 to 4, further comprising a silicone-based surface conditioner (D).
The content ratio of the acrylic polyol (A) and the polyether polyol (B) is 50/50 to 90/10 (mass ratio),
The coating composition according to any one of claims 1 to 4, further comprising a silicon-based surface conditioner (D).
Applying the coating composition according to any one of claims 1 to 7 to an object to be coated;
Curing the coating composition applied to the object to form a coating film.
The method for forming a coating film according to claim 8, wherein the coating material has a glitter coating film containing a glitter pigment formed on a surface thereof.
The method for forming a coating film according to claim 8, wherein the object to be coated is a resin base material or a resin base material having a glitter coating containing a glitter pigment formed on a surface thereof.
(8) A coated body having a coating film formed by curing the coating composition according to any one of (1) to (7).