JP2023157445A - Coating composition and multilayer coating film formation method - Google Patents

Abstract

To provide a coating composition which enables formation of a coating film that is excellent in decontamination property, and decontamination property after outdoor exposure.SOLUTION: A coating composition contains a hydroxyl group-containing resin (A), a crosslinking agent (B), reactive functional group-containing organopolysiloxane (C), and a silica particle (D) dispersion to which a hydroxyl group-containing acrylic resin (d2) is bonded, and an ultraviolet absorber (d31) and/or a hindered amine-based photostabilizer (d32) is bonded. The hydroxyl group-containing resin (A) contains a resin (A') having a hydroxyl group and an alkoxysilyl group.SELECTED DRAWING: None

Description

The present invention relates to a coating composition and a method for forming a multilayer coating film.

Paints applied to objects such as automobile bodies, trucks, motorcycles, buses, automobile parts, railway vehicles, industrial equipment, buildings, and structures are required to have excellent coating film appearance. Furthermore, in recent years, there has been a demand for stain removability such as the ability to easily remove graffiti caused by oil-based ink or the like on paint films.

For example, Patent Document 1 describes a matting agent (A) in which organic fine particles are dispersed in an organic solvent, a copolymer (B) having an organosiloxane chain in the main chain or side chain, and a fluororesin (C). It is disclosed that the coating composition containing the patent provides a coating film appearance with reduced gloss and is excellent in removing stains from lacquers, oil-based inks, and the like.

Japanese Patent Application Publication No. 2008-127424

Although the technique described in Patent Document 1 has excellent contamination removal properties, the contamination removal properties after outdoor exposure may not be sufficient.

An object of the present invention is to provide a coating composition that can form a coating film with excellent stain removal properties and stain removal properties after outdoor exposure.

As a result of extensive studies to achieve the above object, the present inventors have discovered a hydroxyl group-containing resin (A), a crosslinking agent (B), a reactive functional group-containing organopolysiloxane (C), and a hydroxyl group-containing acrylic resin. According to a coating composition containing a dispersion of silica particles (D) to which (d2) is bound and an ultraviolet absorber (d31) and/or a hindered amine light stabilizer (d32) is bound, the above-mentioned objective can be achieved. We found that it is possible to achieve

That is, the present invention relates to the following <1> to <16>.
<1> Hydroxyl group-containing resin (A),
crosslinking agent (B),
a reactive functional group-containing organopolysiloxane (C), and
A coating composition containing a silica particle (D) dispersion bound to a hydroxyl group-containing acrylic resin (d2) and bound to an ultraviolet absorber (d31) and/or a hindered amine light stabilizer (d32).
<2> The coating composition according to <1>, wherein the hydroxyl group-containing resin (A) includes a resin (A') having a hydroxyl group and an alkoxysilyl group.
<3> The coating composition according to <1> or <2>, wherein the hydroxyl group-containing resin (A) contains a hydroxyl group-containing acrylic resin (A1).
<4> The coating composition according to any one of <1> to <3>, wherein the crosslinking agent (B) contains a polyisocyanate compound (B1).
<5> The ultraviolet absorber (d31) and/or the hindered amine light stabilizer (d32) are bonded to the hydroxyl group-containing acrylic resin (d2), and the ultraviolet absorber (d31) and/or the hindered amine light stabilizer (d32) The coating composition according to any one of <1> to <4>, wherein the hydroxyl group-containing acrylic resin (d2) to which the dirt amine light stabilizer (d32) is bonded is bonded to the silica particles (D).
<6> The silica particle (D) dispersion contains a reaction product of the silica particle (d1) having a polymerizable unsaturated group and the polymerizable unsaturated monomer mixture (d2-1), and The monomer mixture (d2-1) contains, as at least a part of its components, a hydroxyl group-containing polymerizable unsaturated monomer, a polymerizable unsaturated monomer bound to an ultraviolet absorber (d31), and a hindered amine light stabilizer (d32). ) is bonded to at least one polymerizable unsaturated monomer selected from polymerizable unsaturated monomers.
<7> The polymerizable unsaturated monomer to which the ultraviolet absorber (d31) is bonded and the polymerizable unsaturated monomer to which the hindered amine light stabilizer (d32) is bonded in the polymerizable unsaturated monomer mixture (d2-1). The coating composition according to <6>, wherein the total proportion of saturated monomers is within the range of 0.5 to 40% by mass based on the total amount of the polymerizable unsaturated monomer mixture (d2-1).
<8> The coating composition according to <6> or <7>, wherein the polymerizable unsaturated monomer mixture (d2-1) further contains an alkoxysilyl group-containing polymerizable unsaturated monomer.
<9> The coating composition according to any one of <6> to <8>, wherein the polymerizable unsaturated monomer mixture (d2-1) further contains a polysiloxane chain-containing polymerizable unsaturated monomer.
<10> The mass ratio of the silica particles having a polymerizable unsaturated group (d1) and the polymerizable unsaturated monomer mixture (d2-1) is 20/80 in the ratio of (d1)/(d2-1). The coating composition according to any one of <6> to <9>, which is within the range of 90/10.
<11> The ultraviolet absorber (d31) and/or the hindered amine light stabilizer (d32) are bonded to the silica particles (D) independently of the hydroxyl group-containing acrylic resin (d2), < The coating composition according to any one of 1> to <10>.
<12> The silica particle (D) dispersion is a silica particle (d1') to which an ultraviolet absorber (d31) and/or a hindered amine light stabilizer (d32) is bonded and has a polymerizable unsaturated group. and a polymerizable unsaturated monomer mixture (d2-1'), and the polymerizable unsaturated monomer mixture (d2-1') contains a hydroxyl group-containing polymerizable unsaturated monomer as at least a part of its components. Polymerization in which the polymerizable unsaturated monomer mixture (d2-1') containing a saturated monomer is bonded to a polymerizable unsaturated monomer to which an ultraviolet absorber (d31) is bonded and a hindered amine light stabilizer (d32). The coating composition according to <11>, which does not contain a sexually unsaturated monomer.
<13> The coating composition according to <12>, wherein the polymerizable unsaturated monomer mixture (d2-1') further contains an alkoxysilyl group-containing polymerizable unsaturated monomer.
<14> The coating composition according to <12> or <13>, wherein the polymerizable unsaturated monomer mixture (d2-1') further contains a polysiloxane chain-containing polymerizable unsaturated monomer.
<15> Silica particles (d1') to which the ultraviolet absorber (d31) and/or hindered amine light stabilizer (d32) are bonded and have a polymerizable unsaturated group, and the polymerizable unsaturated monomer mixture Any one of <12> to <14>, wherein the mass ratio with (d2-1') is within the range of 20/80 to 90/10 in terms of the ratio of (d1')/(d2-1') The coating composition described in .
<16> A method for forming a multi-layer coating film by sequentially coating an object with at least one layer of colored paint and at least one layer of clear coat paint, wherein <1 as the uppermost layer of clear coat paint. A method for forming a multilayer coating film, the method comprising coating the coating composition according to any one of >> to <15>.

According to the coating composition of the present invention, a coating film with excellent stain removal properties and stain removal properties after outdoor exposure can be formed.

The present invention will be described in detail below, but these are just examples of preferred embodiments, and the present invention is not limited to these details.

The coating composition of the present invention (hereinafter sometimes abbreviated as "the present coating") comprises a hydroxyl group-containing resin (A); a crosslinking agent (B); a reactive functional group-containing organopolysiloxane (C); and a hydroxyl group-containing resin (A); This is a coating composition containing a silica particle (D) dispersion bound to an acrylic resin (d2) and bound to an ultraviolet absorber (d31) and/or a hindered amine light stabilizer (d32).

Hydroxyl group-containing resin (A)
The hydroxyl group-containing resin (A) is a resin having at least one hydroxyl group in one molecule. As the hydroxyl group-containing resin (A), a wide variety of known resins can be used, such as hydroxyl group-containing acrylic resins, hydroxyl group-containing polyester resins, hydroxyl group-containing polyurethane resins, hydroxyl group-containing acrylic-modified polyester resins, hydroxyl group-containing polyether resins, and hydroxyl group-containing polycarbonates. Examples include resins such as resins, hydroxyl group-containing epoxy resins, and hydroxyl group-containing alkyd resins.

Among them, the hydroxyl group-containing resin (A) is selected from the hydroxyl group-containing acrylic resin (A1), the hydroxyl group-containing polyester resin, and the hydroxyl group-containing polyurethane resin from the viewpoint of the stain removal property of the formed coating film after outdoor exposure. It is preferable that at least one is included, and it is more preferable that a hydroxyl group-containing acrylic resin (A1) is included.

Furthermore, as the hydroxyl group-containing resin (A), resins (A') having hydroxyl groups and alkoxysilyl groups may be used, such as acrylic resins having hydroxyl groups and alkoxysilyl groups, and polyester resins having hydroxyl groups and alkoxysilyl groups. . These can be used alone or in combination of two or more.

Hydroxyl group-containing acrylic resin (A1)
The hydroxyl group-containing acrylic resin (A1) can be obtained, for example, by copolymerizing a hydroxyl group-containing polymerizable unsaturated monomer and other polymerizable unsaturated monomers (polymerizable unsaturated monomers other than the hydroxyl group-containing polymerizable unsaturated monomer). I can do it.

The hydroxyl group-containing polymerizable unsaturated monomer is a compound having one or more hydroxyl groups and one or more polymerizable unsaturated bonds in one molecule. Examples of the hydroxyl group-containing polymerizable unsaturated monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Monoesterified product of (meth)acrylic acid and dihydric alcohol having 2 to 8 carbon atoms; ε-caprolactone modified product of monoesterified product of (meth)acrylic acid and dihydric alcohol containing 2 to 8 carbon atoms; ( Adducts of meth)acrylic acid and epoxy group-containing compounds (for example, "Cardura E10P" (trade name, manufactured by Hexion, neodecanoic acid glycidyl ester); N-hydroxymethyl (meth)acrylamide; allyl alcohol; Examples include (meth)acrylate having a polyoxyethylene chain in which is a hydroxyl group.

As other polymerizable unsaturated monomers that can be copolymerized with the hydroxyl group-containing polymerizable unsaturated monomer, for example, monomers shown in (1) to (8) below can be used. These polymerizable unsaturated monomers can be used alone or in combination of two or more.

(1) Acid group-containing polymerizable unsaturated monomer An acid group-containing polymerizable unsaturated monomer is a compound having one or more acid groups and one or more polymerizable unsaturated bonds in one molecule. Examples of the monomer include carboxyl group-containing monomers such as (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid and maleic anhydride; sulfonic acid group-containing monomers such as vinylsulfonic acid and 2-sulfoethyl (meth)acrylate. Acidic acids such as 2-(meth)acryloyloxyethyl acid phosphate, 2-(meth)acryloyloxypropyl acid phosphate, 2-(meth)acryloyloxy-3-chloropropyl acid phosphate, 2-methacryloyloxyethyl phenyl phosphate, etc. Examples include phosphoric acid ester monomers. These can be used alone or in combination of two or more. When using an acid group-containing polymerizable unsaturated monomer, it is preferable to use an amount such that the acid value of the hydroxyl group-containing acrylic resin (A1) is within the range of 0.5 to 15 mgKOH/g, and 1 to 10 mgKOH/g. It is preferable to set the amount within the range.

(2) Esterified products of acrylic acid or methacrylic acid and monohydric alcohol having 1 to 20 carbon atoms. Specifically, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, ) acrylate, iso-butyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, isomyristyl (meth)acrylate, stearyl (meth)acrylate, isostearyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name), lauryl (meth)acrylate, tridecyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, etc. .
(3) Alkoxysilyl group-containing polymerizable unsaturated monomer The alkoxysilyl group-containing polymerizable unsaturated monomer is a compound having one or more alkoxysilyl groups and one or more polymerizable unsaturated bonds in one molecule. Examples of the alkoxysilyl group-containing polymerizable unsaturated monomer include vinyltrimethoxysilane, vinyltriethoxysilane, acryloxyethyltrimethoxysilane, methacryloxyethyltrimethoxysilane, acryloxypropyltrimethoxysilane, and methacryloxypropyltrimethoxysilane. Examples include methoxysilane, acryloxypropyltriethoxysilane, methacryloxypropyltriethoxysilane, and vinyltris(β-methoxyethoxy)silane.

The above-mentioned alkoxysilyl group-containing polymerizable unsaturated monomers include vinyltrimethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-methacryloxypropyl Trimethoxysilane is preferred, and γ-methacryloxypropyltrimethoxysilane is more preferred.

Commercially available products can be used as the alkoxysilyl group-containing polymerizable unsaturated monomer. Examples of the commercially available products include "KBM-1003", "KBE-1003", "KBM-502", "KBM-503", "KBE-502", "KBE-503", "KBM-5103", " KBM-5803” (manufactured by Shin-Etsu Chemical Co., Ltd.), “Y-9936,” “A-174” (manufactured by Momentive Performance Materials Japan LLC), “OFS-6030,” “Z- 6033'' (manufactured by Dow Corning Toray Co., Ltd.).

(4) Aromatic vinyl monomer Specific examples include styrene, α-methylstyrene, vinyltoluene, and the like.

By using an aromatic vinyl monomer as a constituent component, the glass transition temperature of the resulting resin increases, and a hydrophobic coating film with a high refractive index can be obtained, which improves the finished appearance by improving the gloss of the coating film. It is possible to obtain the improvement effect of

When an aromatic vinyl monomer is used as a constituent component, its blending ratio is preferably within the range of 3 to 50% by mass, and preferably within the range of 5 to 40% by mass, based on the total amount of monomer components. More preferred.

(5) Glycidyl group-containing polymerizable unsaturated monomer A glycidyl group-containing polymerizable unsaturated monomer is a compound having one or more glycidyl groups and one or more polymerizable unsaturated bonds in one molecule. Acrylate, glycidyl methacrylate, etc. can be mentioned.

(6) Polymerizable unsaturated bond-containing nitrogen atom-containing compound For example, (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-[3-(dimethylamino)propyl](meth)acrylamide, N-butoxymethyl Examples include (meth)acrylamide, diacetone (meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate, vinylpyridine, vinylimidazole, acrylonitrile, and methacrylonitrile.

(7) Polysiloxane chain-containing polymerizable unsaturated monomer The polysiloxane chain-containing polymerizable unsaturated monomer is a compound having one or more polysiloxane chains and one or more polymerizable unsaturated bonds in one molecule. Specifically, siloxane group-containing mono(meth)acrylate monomers and the like can be mentioned. Commercially available products can be used as the polysiloxane chain-containing polymerizable unsaturated monomer. Such commercial products include, for example, "Silaplane FM-0721", "Silaplane FM-0711", "Silaplane FM-0725" (manufactured by JNC), "X-22-174ASX", "X- Examples include "22-174BX", "KF-2012", "X-22-2426", "X-22-2404", and "X-22-2475" (all manufactured by Shin-Etsu Chemical Co., Ltd.).

(8) Other vinyl compounds Examples include vinyl acetate, vinyl propionate, vinyl chloride, vinyl versatate, and the like. Examples of versatile vinyl esters include commercially available products such as "Beova 9" and "Beova 10" (trade names, manufactured by Mitsubishi Chemical Corporation).

As other polymerizable unsaturated monomers, one or more of the monomers shown in (1) to (8) above can be used.

In the present invention, the polymerizable unsaturated monomer refers to a monomer having one or more (for example, 1 to 4) polymerizable unsaturated groups. A polymerizable unsaturated group means an unsaturated group that can undergo radical polymerization. Examples of such polymerizable unsaturated groups include vinyl group, (meth)acryloyl group, (meth)acrylamide group, vinyl ether group, allyl group, propenyl group, isopropenyl group, and maleimide group.

Moreover, in this specification, "(meth)acrylate" means acrylate or methacrylate. "(Meth)acrylic acid" means acrylic acid or methacrylic acid. Moreover, "(meth)acryloyl" means acryloyl or methacryloyl. Moreover, "(meth)acrylamide" means acrylamide or methacrylamide.

The hydroxyl value of the hydroxyl group-containing acrylic resin (A1) is preferably within the range of 70 to 200 mgKOH/g, and preferably 80 to 185 mgKOH/g, from the viewpoint of stain removability after outdoor exposure of the formed coating film. More preferably, it is within the range of 90 to 170 mgKOH/g.

Further, the weight average molecular weight of the hydroxyl group-containing acrylic resin (A1) is preferably within the range of 2,000 to 50,000, and preferably within the range of 3,000 to 30,000, from the viewpoint of stain removability after outdoor exposure of the formed coating film. It is more preferably within the range, and even more preferably within the range of 4,000 to 10,000.

In addition, in this specification, the average molecular weight is a value calculated based on the molecular weight of standard polystyrene from a chromatogram measured by gel permeation chromatography. As a gel permeation chromatograph, "HLC8120GPC" (manufactured by Tosoh Corporation) was used. Four columns were used: "TSKgel G-4000HXL", "TSKgel G-3000HXL", "TSKgel G-2500HXL", and "TSKgel G-2000HXL" (all manufactured by Tosoh Corporation, product names). The measurement was carried out under the following conditions: mobile phase: tetrahydrofuran, measurement temperature: 40°C, flow rate: 1 mL/min, detector: RI.

In addition, the glass transition temperature of the hydroxyl group-containing acrylic resin (A1) is preferably within the range of -50 to 60°C, from the viewpoint of stain removal properties after outdoor exposure of the formed coating film, and 10 to 60°C. The temperature is more preferably within the range of 50°C, and even more preferably within the range of 20 to 45°C.

In this specification, the glass transition temperature (°C) of the acrylic resin was calculated using the following formula.

1/Tg(K)=W1/T1+W2/T2+...Wn/Tn
Tg (℃) = Tg (K) - 273
In the formula, W1, W2,...Wn are the mass fractions of each monomer, and T1, T2...Tn are the glass transition temperatures Tg (K) of the homopolymer of each monomer.
Note that the glass transition temperature of the homopolymer of each monomer is as described in POLYMER HANDBOOK Fourth Edition, J. Brandrup, E. h. Immergut, E. A. The glass transition temperature of monomers that are not described in this document are those obtained by synthesizing a homopolymer of the monomer with a weight average molecular weight of approximately 50,000, and calculating its glass transition temperature. This is the value measured by Seiko Electronics Industries "DSC220U" (differential scanning calorimeter). For the measurement, 50 mg of the sample was weighed out into a special sample dish, dried at 130°C for 3 hours, and then heated from -50°C to 150°C at a rate of 10°C/min in an inert gas. This was done by reading the temperature at the inflection point of the obtained calorific value change curve.

The copolymerization method for copolymerizing the above monomer mixture to obtain the hydroxyl group-containing acrylic resin (A1) is not particularly limited, and any known copolymerization method can be used. Among them, a solution polymerization method in which polymerization is carried out in the presence of a polymerization initiator can be suitably used.

Examples of organic solvents used in the above solution polymerization method include aromatic solvents such as toluene, xylene, and "Swasol 1000" (manufactured by Cosmo Oil Co., Ltd., trade name, high boiling point petroleum solvent); ethyl acetate, butyl acetate. , propyl propionate, butyl propionate, 1-methoxy-2-propyl acetate, 2-ethoxyethyl propionate, 3-methoxybutyl acetate, ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, and other ester solvents. Ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and methyl amyl ketone; Alcohol solvents such as 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, and 2-ethylhexanol. .

These organic solvents can be used alone or in combination of two or more, but from the viewpoint of solubility of the acrylic resin, it is preferable to use ester solvents and aromatic solvents.

Examples of the polymerization initiator that can be used in the copolymerization of the hydroxyl group-containing acrylic resin (A1) include 2,2'-azobisisobutyronitrile, benzoyl peroxide, di-t-butyl peroxide, and di-t- Known radical polymerization initiators such as amyl peroxide, t-butyl peroctoate, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), etc. can be mentioned.

The hydroxyl group-containing acrylic resin (A1) can be used alone or in combination of two or more.

The hydroxyl group-containing acrylic resin (A1) preferably contains a secondary hydroxyl group-containing acrylic resin (A1') from the viewpoint of the finished appearance of the formed coating film.

The secondary hydroxyl group-containing acrylic resin (A1') is, for example, a secondary hydroxyl group-containing polymerizable unsaturated monomer as one type of the hydroxyl group-containing polymerizable unsaturated monomer in the method for producing the hydroxyl group-containing acrylic resin (A1). It can be manufactured by using

Examples of the above-mentioned secondary hydroxyl group-containing polymerizable unsaturated monomers include carbon atoms of alkyl groups in ester moieties such as 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 3-hydroxybutyl (meth)acrylate. A polymerizable unsaturated monomer having 2 to 8, preferably 3 to 6, more preferably 3 or 4 secondary hydroxyl groups; (meth)acrylic acid and an epoxy group-containing compound (for example, "Cardura E10P" (trade name) , neodecanoic acid glycidyl ester (manufactured by Hexion), etc.These can be used alone or in combination of two or more.Among them, from the viewpoint of the finished appearance of the coating film formed, etc. 2-hydroxypropyl (meth)acrylate can be suitably used.

In the secondary hydroxyl group-containing acrylic resin (A1'), the content ratio of the secondary hydroxyl group-containing polymerizable unsaturated monomer is determined based on the total amount of copolymerizable monomer components, from the viewpoint of the finished appearance of the coating film formed. , preferably within the range of 5 to 45% by mass, more preferably within the range of 10 to 40% by mass.

In the secondary hydroxyl group-containing acrylic resin (A1'), the content ratio of the secondary hydroxyl group-containing polymerizable unsaturated monomer in the total amount of the hydroxyl group-containing polymerizable unsaturated monomer is determined by the water resistance of the formed coating film, From the viewpoint of finished appearance etc., it is preferably within the range of 30 to 100% by mass, more preferably within the range of 35 to 100% by mass, and even more preferably within the range of 40 to 100% by mass. .

Further, the hydroxyl group-containing acrylic resin (A1) preferably contains an acrylic resin (A1'') having a hydroxyl group and an alkoxysilyl group, from the viewpoint of stain removal properties of the formed coating film after outdoor exposure.

For example, in the method for producing the hydroxyl group-containing acrylic resin (A1), the acrylic resin (A1'') having a hydroxyl group and an alkoxysilyl group is used as one of the other polymerizable unsaturated monomers. It can be produced by using a polymerizable unsaturated monomer (3).

The above acrylic resin (A1'') having a hydroxyl group and an alkoxysilyl group has an alkoxysilyl group, so that in addition to the crosslinking bond between the hydroxyl group and the crosslinking agent (B), the condensation reaction between the alkoxylyl groups and the alkoxysilyl group Since a crosslinking bond is generated by the reaction between the hydroxyl group and the hydroxyl group, it is possible to improve the contamination removability and curability of the formed coating film after outdoor exposure.

In the acrylic resin (A1'') having a hydroxyl group and an alkoxysilyl group, the content ratio of the alkoxysilyl group-containing polymerizable unsaturated monomer is determined from the viewpoint of stain removability after outdoor exposure of the formed coating film, etc. It is preferably within the range of 3 to 60% by mass, more preferably within the range of 5 to 50% by mass, and preferably within the range of 5 to 30% by mass, based on the total amount of copolymerization monomer components. is even more preferable.

In addition, the hydroxyl group-containing acrylic resin (A1) is selected from the above-mentioned secondary hydroxyl-containing acrylic resin (A1') or the above-mentioned acrylic resin having a hydroxyl group and an alkoxysilyl group, from the viewpoint of stain removability after outdoor exposure of the formed coating film. It is preferable that the resin (A1'') contains an acrylic resin (A1'') having a secondary hydroxyl group and an alkoxysilyl group.

The acrylic resin (A1''') having a secondary hydroxyl group and an alkoxysilyl group may be used, for example, as one of the other polymerizable unsaturated monomers in the method for producing the secondary hydroxyl group-containing acrylic resin (A1'). can be produced by using the alkoxysilyl group-containing polymerizable unsaturated monomer (3).

In the acrylic resin (A1''') having a secondary hydroxyl group and an alkoxysilyl group, the content ratio of the secondary hydroxyl group-containing polymerizable unsaturated monomer is determined from the viewpoint of the finished appearance of the coating film formed, etc. It is preferably within the range of 5 to 45% by mass, more preferably 10 to 40% by mass, based on the total amount of monomer components.

In addition, in the acrylic resin (A1''') having a secondary hydroxyl group and an alkoxysilyl group, the content ratio of the secondary hydroxyl group-containing polymerizable unsaturated monomer in the total amount of the hydroxyl group-containing polymerizable unsaturated monomer is From the viewpoint of water resistance, finished appearance, etc. of the coating film, it is preferably within the range of 30 to 100% by mass, more preferably within the range of 35 to 100% by mass, and in the range of 40 to 100% by mass. It is more preferable that the range is within

In addition, in the acrylic resin (A1''') having a secondary hydroxyl group and an alkoxysilyl group, the content ratio of the alkoxysilyl group-containing polymerizable unsaturated monomer is determined by the contamination removability of the formed coating film after outdoor exposure. From the viewpoint of finish appearance, etc., the amount is preferably 3 to 60% by mass, more preferably 5 to 50% by mass, and within the range of 5 to 30% by mass, based on the total amount of copolymerized monomer components. It is even more preferable that there be.

In the coating composition of the present invention, when the hydroxyl group-containing resin (A) contains the hydroxyl group-containing acrylic resin (A1), the content of the hydroxyl group-containing acrylic resin (A1) is determined after outdoor exposure of the formed coating film. From the viewpoint of stain removability, water resistance, finished appearance, etc., the amount should be within the range of 40 to 95 parts by mass based on 100 parts by mass of the total solid content of the hydroxyl group-containing resin (A) and the crosslinking agent (B). It is preferably in the range of 50 to 85 parts by weight, more preferably in the range of 55 to 75 parts by weight.

Furthermore, in the coating composition of the present invention, when the hydroxyl group-containing resin (A) contains the acrylic resin (A1''') having the secondary hydroxyl group and alkoxysilyl group, The content of the acrylic resin (A1''') is determined based on the hydroxyl group-containing resin (A) and crosslinking agent (B) from the viewpoint of stain removability after outdoor exposure of the formed coating film, water resistance, finished appearance, etc. It is preferably within the range of 40 to 95 parts by mass, more preferably within the range of 50 to 85 parts by mass, and preferably within the range of 55 to 75 parts by mass, based on 100 parts by mass of total solid content. is even more preferable.

The hydroxyl group-containing polyester resin can be produced by a conventional method, for example, by an esterification reaction between a polybasic acid and a polyhydric alcohol. The polybasic acid is a compound having two or more carboxyl groups in one molecule, such as phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, tetrahydrophthalic acid, hexa Examples include hydrophthalic acid, maleic acid, fumaric acid, itaconic acid, trimellitic acid, pyromellitic acid, and anhydrides thereof. Further, the polyhydric alcohol is a compound having two or more hydroxyl groups in one molecule, and examples thereof include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,5-pentanediol. Diol, 1,6-hexanediol, 2,2-diethyl-1,3-propanediol, neopentyl glycol, 1,9-nonanediol, 1,4-cyclohexanediol, hydroxypivalic acid neopentyl glycol ester, 2- Diols such as butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethylpentanediol, hydrogenated bisphenol A; and trimethylolpropane, trimethylol Trivalent or higher polyol components such as ethane, glycerin, and pentaerythritol; and 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, 2,2-dimethylolpentanoic acid, and 2,2-dimethylol Examples include hydroxycarboxylic acids such as hexanoic acid and 2,2-dimethyloloctanoic acid.

In addition, alpha-olefin epoxides such as propylene oxide and butylene oxide, and monoepoxy compounds such as "Cardura E10P" (manufactured by Hexion, trade name, glycidyl ester of synthetic highly branched saturated fatty acids) can be reacted with acids. Compounds may also be incorporated into polyester resins.

When introducing a carboxyl group into a polyester resin, it can also be introduced by, for example, adding an acid anhydride to a hydroxyl group-containing polyester to half-esterify it.

The hydroxyl value of the hydroxyl group-containing polyester resin is preferably within the range of 80 to 250 mgKOH/g, more preferably within the range of 100 to 200 mgKOH/g.

The weight average molecular weight of the hydroxyl group-containing polyester resin is preferably within the range of 500 to 3,500, more preferably within the range of 500 to 2,500.

In the coating composition of the present invention, when containing a hydroxyl group-containing polyester resin, the content of the hydroxyl group-containing polyester resin is based on 100 parts by mass of the total solid content of the hydroxyl group-containing resin (A) and the crosslinking agent (B). It is preferably within the range of 1 to 30 parts by weight, more preferably within the range of 2 to 25 parts by weight, and even more preferably within the range of 3 to 20 parts by weight.

Examples of the hydroxyl group-containing polyurethane resin include hydroxyl group-containing polyurethane resins obtained by reacting a polyol compound and a polyisocyanate compound.

Examples of the polyol compound include low molecular weight compounds such as dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, and hexamethylene glycol, trihydric alcohols such as trimethylolpropane and glycerin, and polyhydric alcohols such as pentaerythritol. alcohols and the like. Examples of high molecular weight polyols include polyether polyols, polyester polyols, acrylic polyols, and epoxy polyols. Examples of polyether polyols include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like. Examples of polyester polyols include the above-mentioned dihydric alcohols, alcohols such as dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol, and dibasic acids such as adipic acid, azelaic acid, and sebacic acid. Examples include polycondensates of polycondensates, lactone-based ring-opening polymer polyols such as polycaprolactone, polycarbonate diols, and the like. Further, carboxyl group-containing polyols such as 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid can also be used.

As the polyisocyanate compound to be reacted with the above-mentioned polyol compound, for example, the polyisocyanate compounds described in the description section of the crosslinking agent (B) below can be used.

The hydroxyl value of the hydroxyl group-containing polyurethane resin is preferably within the range of 80 to 250 mgKOH/g, more preferably within the range of 100 to 200 mgKOH/g.

The weight average molecular weight of the hydroxyl group-containing polyurethane resin is preferably within the range of 500 to 10,000, more preferably within the range of 1,000 to 5,000.

In the coating composition of the present invention, when containing a hydroxyl group-containing polyurethane resin, the content of the hydroxyl group-containing polyurethane resin is based on 100 parts by mass of the total solid content of the hydroxyl group-containing resin (A) and the crosslinking agent (B). It is preferably within the range of 1 to 30 parts by weight, more preferably within the range of 2 to 25 parts by weight, and even more preferably within the range of 3 to 20 parts by weight.

In addition, in the coating composition of the present invention, the content of the hydroxyl group-containing resin (A) is determined from the viewpoint of stain removability, water resistance, and finished appearance of the formed coating film after outdoor exposure. It is preferably within the range of 40 to 95 parts by mass, more preferably within the range of 50 to 85 parts by mass, based on 100 parts by mass of the total solid content of A) and the crosslinking agent (B), and is more preferably within the range of 55 to 85 parts by mass. More preferably, the amount is within the range of 75 parts by mass.

Crosslinking agent (B)
The crosslinking agent (B) is a compound having a functional group that can react with the hydroxyl group in the hydroxyl group-containing resin (A).

As the crosslinking agent (B), specifically, for example, polyisocyanate compounds, blocked polyisocyanate compounds, amino resins, etc. can be suitably used. Among these, from the viewpoint of stain removability and finished appearance of the formed coating film after outdoor exposure, it is preferable that the crosslinking agent (B) contains a polyisocyanate compound and/or an amino resin. It is particularly preferable to contain.

The above polyisocyanate compound is a compound having at least two isocyanate groups in one molecule, such as an aliphatic polyisocyanate compound, an alicyclic polyisocyanate compound, an araliphatic polyisocyanate compound, an aromatic polyisocyanate compound. , derivatives of the polyisocyanate compound, and the like.

Examples of the aliphatic polyisocyanate compounds include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1, Aliphatic diisocyanate compounds such as 3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, dimer acid diisocyanate, methyl 2,6-diisocyanatohexanoate (common name: lysine diisocyanate) 2-isocyanatoethyl 2,6-diisocyanatohexanoate, 1,6-diisocyanato-3-isocyanatomethylhexane, 1,4,8-triisocyanatooctane, 1,6,11-triisocyanatoundecane , 1,8-diisocyanato-4-isocyanatomethyloctane, 1,3,6-triisocyanatohexane, 2,5,7-trimethyl-1,8-diisocyanato-5-isocyanatomethyloctane, etc. Examples include isocyanate compounds.

Examples of the alicyclic polyisocyanate compound include 1,3-cyclopentene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (commonly used name: isophorone diisocyanate), 4-methyl-1,3-cyclohexylene diisocyanate (common name: hydrogenated TDI), 2-methyl-1,3-cyclohexylene diisocyanate, 1,3- or 1,4-bis(isocyanate) Alicyclic diisocyanate compounds such as natomethyl)cyclohexane (common name: hydrogenated xylylene diisocyanate) or mixtures thereof, methylenebis(4,1-cyclohexanediyl) diisocyanate (common name: hydrogenated MDI), norbornane diisocyanate; 1,3 , 5-triisocyanatocyclohexane, 1,3,5-trimethylisocyanatocyclohexane, 2-(3-isocyanatopropyl)-2,5-di(isocyanatomethyl)-bicyclo(2.2.1)heptane, 2-(3-isocyanatopropyl)-2,6-di(isocyanatomethyl)-bicyclo(2.2.1)heptane, 3-(3-isocyanatopropyl)-2,5-di(isocyanatomethyl) )-bicyclo(2.2.1)heptane, 5-(2-isocyanatoethyl)-2-isocyanatomethyl-3-(3-isocyanatopropyl)-bicyclo(2.2.1)heptane, 6- (2-isocyanatoethyl)-2-isocyanatomethyl-3-(3-isocyanatopropyl)-bicyclo(2.2.1)heptane, 5-(2-isocyanatoethyl)-2-isocyanatomethyl- 2-(3-isocyanatopropyl)-bicyclo(2.2.1)-heptane, 6-(2-isocyanatoethyl)-2-isocyanatomethyl-2-(3-isocyanatopropyl)-bicyclo(2 .2.1) Alicyclic triisocyanate compounds such as heptane can be mentioned.

Examples of the araliphatic polyisocyanate compound include methylene bis(4,1-phenylene) diisocyanate (common name: MDI), 1,3- or 1,4-xylylene diisocyanate or a mixture thereof, ω,ω'-diisocyanate. -Aroaliphatic diisocyanate compounds such as 1,4-diethylbenzene, 1,3- or 1,4-bis(1-isocyanato-1-methylethyl)benzene (common name: tetramethylxylylene diisocyanate) or mixtures thereof; 1 , 3,5-triisocyanatomethylbenzene and other aromatic aliphatic triisocyanate compounds.

Examples of the aromatic polyisocyanate compound include m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 2,4-tolylene diisocyanate (common name: 2,4 Aromatic diisocyanate compounds such as -TDI) or 2,6-tolylene diisocyanate (common name: 2,6-TDI) or mixtures thereof, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate; triphenylmethane - Aromatic triisocyanate compounds such as 4,4',4''-triisocyanate, 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene; 4,4'-diphenylmethane-2 , 2',5,5'-tetraisocyanate and other aromatic tetraisocyanate compounds.

Examples of derivatives of the polyisocyanate compounds include dimers, trimers, biurets, allophanates, uretdione, uretoimines, isocyanurates, oxadiazinetriones, polymethylene polyphenyl polyisocyanates (crude MDI, polymeric MDI), crude TDI, etc.

The above polyisocyanate compounds and derivatives thereof may be used alone or in combination of two or more.

As the above-mentioned polyisocyanate compound, at least one selected from aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds, and derivatives thereof is used from the viewpoint of stain removability after outdoor exposure of the formed coating film. It is preferable to use an aliphatic polyisocyanate compound and/or a derivative thereof from the viewpoint of high solidification of the resulting coating composition, finished appearance of the formed coating film, and stain removability after outdoor exposure. More preferred.

As the aliphatic polyisocyanate compound and/or its derivative, from the viewpoint of high solidity of the resulting coating composition, finished appearance of the formed coating film, etc., aliphatic diisocyanate compound and/or its isocyanurate are particularly preferred. It is preferable to use hexamethylene diisocyanate and/or its isocyanurate form.

When the coating composition of the present invention contains the above-mentioned polyisocyanate compound as the crosslinking agent (B), the content of the polyisocyanate compound is determined in terms of the finished appearance of the formed coating film and the stain removability after outdoor exposure. From this point of view, it is preferably within the range of 5 to 60 parts by mass, and within the range of 15 to 50 parts by mass, based on 100 parts by mass of the total solid content of the hydroxyl group-containing resin (A) and crosslinking agent (B). It is more preferable that the amount is within the range of 20 to 45 parts by mass.

The blocked polyisocyanate compound that can be used as the crosslinking agent (B) is a compound in which the isocyanate groups of the polyisocyanate compound are blocked with a blocking agent.

Examples of the blocking agent include phenols such as phenol, cresol, xylenol, nitrophenol, ethylphenol, hydroxydiphenyl, butylphenol, isopropylphenol, nonylphenol, octylphenol, and methyl hydroxybenzoate; ε-caprolactam, δ-valerolactam, Lactams such as γ-butyrolactam and β-propiolactam; aliphatic alcohols such as methanol, ethanol, propyl alcohol, butyl alcohol, amyl alcohol, lauryl alcohol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono Ethers such as butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, methoxymethanol; benzyl alcohol, glycolic acid, methyl glycolate, ethyl glycolate, butyl glycolate, lactic acid, methyl lactate, ethyl lactate, lactic acid Alcohols such as butyl, methylol urea, methylol melamine, diacetone alcohol, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate; formamide oxime, acetamid oxime, acetoxime, methyl ethyl ketoxime, diacetyl monoxime, benzophenone oxime, cyclohexane oxime, etc. Oxime series; active methylene series such as dimethyl malonate, diethyl malonate, ethyl acetoacetate, methyl acetoacetate, acetylacetone; butyl mercaptan, t-butyl mercaptan, hexyl mercaptan, t-dodecyl mercaptan, 2-mercaptobenzothiazole, thio Mercaptans such as phenol, methylthiophenol and ethylthiophenol; acidamides such as acetanilide, acetanisidide, acetotoluide, acrylamide, methacrylamide, acetamide, stearamide and benzamide; succinimide, phthalimide, maleimide, etc. Imide series; diphenylamine, phenylnaphthylamine, xylidine, N-phenylxylidine, carbazole, aniline, naphthylamine, butylamine, dibutylamine, butylphenylamine, etc.; amine series; imidazole series, such as imidazole, 2-ethylimidazole; urea, thiourea , urea types such as ethylene urea, ethylene thiourea, and diphenyl urea; carbamate ester types such as phenyl N-phenylcarbamate; imine types such as ethylene imine and propylene imine; sulfite types such as sodium bisulfite and potassium bisulfite; Examples include azole compounds. Examples of the azole compounds include pyrazole, 3,5-dimethylpyrazole, 3-methylpyrazole, 4-benzyl-3,5-dimethylpyrazole, 4-nitro-3,5-dimethylpyrazole, 4-bromo-3, Pyrazole or pyrazole derivatives such as 5-dimethylpyrazole and 3-methyl-5-phenylpyrazole; imidazole or imidazole derivatives such as imidazole, benzimidazole, 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole; 2-methylimidazoline and imidazoline derivatives such as 2-phenylimidazoline.

Among these, preferred blocking agents include oxime-based blocking agents, active methylene-based blocking agents, pyrazole or pyrazole derivatives.

When blocking (reacting the blocking agent), a solvent can be added as necessary. The solvent used in the blocking reaction is preferably one that is not reactive with isocyanate groups, such as acetone, ketones such as methyl ethyl ketone, esters such as ethyl acetate, and N-methyl-2-pyrrolidone (NMP). Examples include solvents such as:

When the coating composition of the present invention contains the above-mentioned blocked polyisocyanate compound as the crosslinking agent (B), the content of the blocked polyisocyanate compound is determined depending on the finished appearance of the formed coating film and the contamination after outdoor exposure. From the viewpoint of removability etc., it is preferably within the range of 5 to 60 parts by mass, and 15 to 50 parts by mass, based on 100 parts by mass of the total solid content of the hydroxyl group-containing resin (A) and crosslinking agent (B). More preferably, the amount is within the range of 20 to 45 parts by mass.

When the coating composition of the present invention contains the polyisocyanate compound and/or the blocked polyisocyanate compound as the crosslinking agent (B), the blending ratio is determined to remove contamination after outdoor exposure of the formed coating film. From the viewpoint of properties and finished appearance, etc., the equivalent ratio (NCO/OH ) is preferably in the range of usually 0.5 to 2, particularly 0.8 to 1.5.

As the amino resin that can be used as the crosslinking agent (B), a partially methylolated amino resin or a fully methylolated amino resin obtained by a reaction between an amino component and an aldehyde component can be used. Examples of the amino component include melamine, urea, benzoguanamine, acetoguanamine, steroguanamine, spiroguanamine, and dicyandiamide. Examples of the aldehyde component include formaldehyde, paraformaldehyde, acetaldehyde, and benzaldehyde.

Furthermore, the methylol group of the above-mentioned methylolated amino resin may be partially or completely etherified with an appropriate alcohol. Examples of the alcohol used for etherification include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, 2-ethylbutanol, 2-ethylhexanol, and the like.

As the amino resin, melamine resin is preferred. As the melamine resin, for example, an alkyl etherified melamine resin in which the methylol group of a partially or completely methylolated melamine resin is partially or completely etherified with the above-mentioned alcohol can be used.

Examples of the alkyl etherified melamine resin include methyl etherified melamine resins in which the methylol groups of partially or fully methylolated melamine resins are partially or completely etherified with methyl alcohol; methylol groups of partially or fully methylolated melamine resins; butyl etherified melamine resin, which is partially or completely etherified with butyl alcohol; methyl-butyl mixed etherification, where the methylol groups of partially or fully methylolated melamine resin are partially or completely etherified with methyl alcohol and butyl alcohol Melamine resin or the like can be suitably used.

Further, the weight average molecular weight of the melamine resin is preferably within the range of 400 to 6,000, more preferably within the range of 500 to 5,000, and even more preferably within the range of 800 to 4,000.

Commercially available products can be used as the melamine resin. Examples of commercially available melamine resins include "Cymel 202," "Cymel 203," "Cymel 238," "Cymel 251," "Cymel 303," "Cymel 323," "Cymel 324," and "Cymel 325." , "Cymel 327", "Cymel 350", "Cymel 385", "Cymel 1156", "Cymel 1158", "Cymel 1116", "Cymel 1130" (all manufactured by Olnex Japan), "Yuban 120", Examples include "Yuban 20HS", "Yuban 20SE60", "Yuban 2021", "Yuban 2028", "Yuban 28-60" (all manufactured by Mitsui Chemicals).

The melamine resins described above can be used alone or in combination of two or more.

When the coating composition of the present invention contains the above-mentioned amino resin as the crosslinking agent (B), the content of the amino resin is determined from the viewpoint of stain removability and finished appearance of the formed coating film after outdoor exposure. , preferably within the range of 1 to 60 parts by mass, and preferably within the range of 3 to 40 parts by mass, based on 100 parts by mass of the total solid content of the hydroxyl group-containing resin (A) and the crosslinking agent (B). More preferably, the amount is in the range of 5 to 30 parts by mass.

The above crosslinking agents (B) can be used alone or in combination of two or more.

Reactive functional group-containing organopolysiloxane (C)
The reactive functional group-containing organopolysiloxane (C) is an organopolysiloxane containing a reactive functional group at the terminal and/or side chain of the molecule.

The above-mentioned reactive functional group-containing organopolysiloxane (C) may be capable of self-crosslinking reaction, and may react with the reactive functional groups of the above-mentioned hydroxyl group-containing resin (A), crosslinking agent (B) and/or silica particles (D). It may be possible to perform both a self-crosslinking reaction and a reaction with the reactive functional group of the hydroxyl group-containing resin (A), the crosslinking agent (B), and/or the silica particles (D).

Examples of the reactive functional group-containing organopolysiloxane (C) include alkoxysilyl group-containing organopolysiloxane, amino group-containing organopolysiloxane, isocyanate group-containing organopolysiloxane, hydroxyl group-containing organopolysiloxane, and epoxy group-containing organopolysiloxane. Examples include siloxane, carboxyl group-containing organopolysiloxane, etc. Among them, alkoxysilyl group-containing organopolysiloxane, amino group-containing organopolysiloxane, etc. It preferably contains at least one selected from siloxane, isocyanate group-containing organopolysiloxane, and hydroxyl group-containing organopolysiloxane, and preferably contains an alkoxysilyl group-containing organopolysiloxane.

Commercial products of the alkoxysilyl group-containing organopolysiloxane include, for example, "SR2406," "SR2410," "SR2420," "SR2416," "SR2402," and "AY42-161" (Toray Dow Corning Silicone Co., Ltd.). ), "FZ-3704", "FZ-3511" (manufactured by Nippon Unicar), "KC-89S", "KR-500", "X-40-9225", "X-40-9246", "X-40-9250", "KR-217", "KR-9218", "KR-213", "KR-510", "X-40-9227", "X-40-9247", "X -41-1053", "X-41-1056", "X-41-1805", "X-41-1810", "X-40-2651", "X-40-2308", "X-40 -9238'', ``X-40-2239'', ``X-40-2327'', ``KR-400'', ``X-40-175'', ``X-40-9740'' (manufactured by Shin-Etsu Chemical Co., Ltd.) , "Silmer TMS C50", "Silmer TMS Di-10", "Silmer TMS Di-50" (manufactured by SILTECH), and other commercially available products are applicable.

The reactive functional group-containing organopolysiloxane (C) preferably contains a hydrocarbon group such as a methyl group or a phenyl group from the viewpoint of stain removal properties of the formed coating film.

The number average molecular weight of the above-mentioned reactive functional group-containing organopolysiloxane (C) is within the range of 200 to 10,000 from the viewpoint of stain removability after outdoor exposure of the formed coating film and finished appearance. It is preferably within the range of 400 to 5,000, more preferably within the range of 500 to 2,000.

The content of the above-mentioned reactive functional group-containing organopolysiloxane (C) is determined from the viewpoints of stain removability of the formed coating film, stain removability after outdoor exposure, transparency, curability, etc. ) and the crosslinking agent (B), based on the total solid content of 100 parts by mass, it is preferably within the range of 0.01 to 10 parts by mass, and more preferably within the range of 0.05 to 1 part by mass. , more preferably within the range of 0.1 to 0.4 parts by mass.

Silica particle (D) dispersion Silica particle (D) dispersion has a hydroxyl group-containing acrylic resin (d2) bound to it, and a UV absorber (d31) and/or a hindered amine light stabilizer (d32) bound to it. It is a dispersion of silica particles. The silica particle (D) dispersion will be explained in more detail below.

Raw material silica particles Silica particles (D) Raw material silica particles for forming a dispersion include a hydroxyl group-containing acrylic resin (d2), an ultraviolet absorber (d31) and/or a hindered amine light stabilizer (d32). Any silica particles that can form bonds can be used without any particular restrictions. Examples of such silica particles include dry silica, wet silica, silica gel, calcium ion exchange silica fine particles, colloidal silica, etc. In particular, those having hydroxyl groups and/or alkoxy groups on the particle surface and dispersing Colloidal silica, which is fine silica particles dispersed in a medium, is preferred.

Examples of the dispersion medium include water; alcohol solvents such as methanol, ethanol, isopropanol, n-propanol, isobutanol, and n-butanol; polyhydric alcohol solvents such as ethylene glycol; ethylene glycol monoethyl ether, and ethylene glycol. Examples include polyhydric alcohol derivatives such as monobutyl ether and propylene glycol monomethyl ether; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and diacetone alcohol. The dispersion medium is preferably a lower alcohol solvent having 3 or less carbon atoms or a lower polyhydric alcohol derivative. This is because it is easy to remove in the solvent removal step in the production of silica particles having polymerizable unsaturated groups.

As the colloidal silica, commercially available products can be used. Such commercial products include, for example, "IPA-ST", "MEK-ST", "NBA-ST", "XBA-ST", "DMAC-ST", "PGM-ST", "ST-UP", "ST-OUP", "ST-20", "ST-40", "ST-C", "ST-N", "ST-O", "ST-50", "ST-OL" (all (manufactured by Nissan Chemical Industries, Ltd.), etc.

The average primary particle diameter of the raw material silica particles is preferably 5 to 100 nm, more preferably 5 to 50 nm. If the average primary particle diameter is less than 5 nm, when the present dispersion is used in combination with other organic materials, the effect of improving mechanical properties etc. may be reduced. When the average primary particle diameter exceeds 100 nm, transparency may be impaired.

As used herein, "average primary particle size" means the median diameter (d50) of a volume-based particle size distribution, and the volume-based particle size distribution is measured by a laser diffraction/scattering method. In the present invention, the volume-based particle size distribution of the present dispersion was measured using a laser diffraction/scattering particle size distribution measuring device "Microtrac NT3300" (trade name, manufactured by Nikkiso Co., Ltd.). At that time, the sample concentration was adjusted to fall within a predetermined transmittance range set in the device.

The silica particle (D) dispersion is made of silica particles in which raw silica particles, a hydroxyl group-containing acrylic resin (d2), and an ultraviolet absorber (d31) and/or a hindered amine light stabilizer (d32) are combined. The dispersion is a dispersion, and its constituent elements, hydroxyl group-containing acrylic resin (d2), ultraviolet absorber (d31), and hindered amine light stabilizer (d32), will be explained below, and then these constituent elements and The mode of bonding with silica particles will be explained.

Hydroxyl group-containing acrylic resin (d2)
The hydroxyl group-containing acrylic resin (d2) can be formed by polymerizing a hydroxyl group-containing polymerizable unsaturated monomer.

The hydroxyl group-containing polymerizable unsaturated monomer is a compound having one or more hydroxyl groups and one or more polymerizable unsaturated groups in one molecule, and examples of the hydroxyl group-containing polymerizable unsaturated monomer include 2-hydroxyethyl ( Monomers of (meth)acrylic acid and dihydric alcohol having 2 to 8 carbon atoms, such as meth)acrylate, 2-hydroxypropyl(meth)acrylate, 3-hydroxypropyl(meth)acrylate, and 4-hydroxybutyl(meth)acrylate. Esterified product; ε-caprolactone modified product of the monoesterified product of the (meth)acrylic acid and a dihydric alcohol having 2 to 8 carbon atoms; (meth)acrylic acid and an epoxy group-containing compound (for example, "Cardura E10P" (product) N-hydroxymethyl (meth)acrylamide; allyl alcohol; and (meth)acrylate having a polyoxyethylene chain with a hydroxyl group at the end of the molecule. be able to.

In addition, in forming the hydroxyl group-containing acrylic resin (d2), as in the case of the hydroxyl group-containing acrylic resin (A1) as the hydroxyl group-containing resin (A), other materials that can be copolymerized with the hydroxyl group-containing polymerizable unsaturated monomer are used. The polymerizable unsaturated monomer may be added to copolymerize with the hydroxyl group-containing polymerizable unsaturated monomer. Examples of such other polymerizable unsaturated monomers include specific examples of compounds having one or more polymerizable unsaturated groups in one molecule ( 1) to (8) can be mentioned.

UV absorber (d31)
As the ultraviolet absorber (d31), conventionally known ones can be used, such as benzotriazole absorbers, triazine absorbers, salicylic acid derivative absorbers, benzophenone absorbers, and the like. Further, the ultraviolet absorber (d31) may have a polymerizable unsaturated group.

Specific examples of the benzotriazole absorbent include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-5'-t-butylphenyl)benzotriazole, 2- (2'-hydroxy-3',5'-di-t-butylphenyl)benzotriazole, 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-t-amylphenyl)benzo Triazole, 2-(2'-hydroxy-4'-octoxyphenyl)benzotriazole, 2-{2'-hydroxy-3'-(3'',4'',5'',6''-tetrahydrophthalimide Examples include methyl)-5'-methylphenyl}benzotriazole, 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, and the like.

Specific examples of the triazine absorbent include 2,4-bis(2,4-dimethylphenyl)-6-(2-hydroxy-4-isooctyloxyphenyl)-1,3,5-triazine, 2 -[4((2-hydroxy-3-dodecyloxypropyl)-oxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2- [4-((2-hydroxy-3-tridecyloxypropyl)-oxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2 -(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine and the like.

Specific examples of the salicylic acid derivative absorbent include phenyl salicylate, p-octylphenyl salicylate, 4-tert-butylphenyl salicylate, and the like.

Specific examples of the benzophenone absorbent include 4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, and 2-hydroxy-4-methoxy-2'-carboxybenzophenone. , 2-hydroxy-4-methoxy-5-sulfobenzophenone trihydrate, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-octade Siloxybenzophenone, sodium 2,2'-dihydroxy-4,4'-dimethoxy-5-sulfobenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 5-chloro- 2-hydroxybenzophenone, resorcinol monobenzoate, 2,4-dibenzoylresorcinol, 4,6-dibenzoylresorcinol, hydroxydodecylbenzophenone, 2,2'-dihydroxy-4(3-methacryloxy-2-hydroxypropoxy)benzophenone, etc. can be mentioned.

Examples of commercially available UV absorbers include "Tinuvin900," "Tinuvin928," "Tinuvin348-2," "Tinuvin479," "Tinuvin405," and "Tinuvin400" (manufactured by BASF, product name, Tinuvin is a registered trademark). ), "RUVA-93" (trade name, manufactured by Otsuka Chemical Co., Ltd.), and the like.

Hindered amine light stabilizer (d32)
As the hindered amine light stabilizer (d32), conventionally known ones such as hindered piperidine compounds can be used. Further, the hindered amine light stabilizer (d32) may have a polymerizable unsaturated group.

Examples of the hindered amine light stabilizer (d32) include bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis(2,2,6,6-tetramethyl-4-piperidinyl) ) sebacate, bis(N-methyl-2,2,6,6-tetramethyl-4-piperidinyl) sebacate, 4-benzoyloxy-2,2',6,6'-tetramethylpiperidine, bis(1,2 , 2,6,6-pentamethyl-4-piperidyl) {[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl}butyl malonate; poly{[6 -(1,1,3,3-tetramethylbutyl)imino-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidyl)imino]hexa Oligomeric types such as methylene [(2,2,6,6-tetramethyl-4-piperidyl)iminol]; 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol and succinic acid Polyester bond type products such as polyesterified products; polymerizable unsaturated products such as 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, 2,2,6,6-tetramethyl-4-piperidyl methacrylate, etc. Examples include those having groups.

Examples of commercially available hindered amine light stabilizers include "Tinuvin765", "Tinuvin770DF", "Tinuvin144", "Tinuvin622SF", "Tinuvin152" (manufactured by BASF, trade name, Tinuvin is a registered trademark), " ADK STAB LA-52", "ADK STAB LA-57", "ADK STAB LA-63P", "ADK STAB LA-72", "ADK STAB LA-77Y", ADK STAB LA-81", "ADK STAB LA-82", "ADK STAB LA-" 87'' (manufactured by ADEKA Co., Ltd., trade name, ADEKA STAB is a registered trademark).

Hydroxyl group-containing acrylic resin (d2), ultraviolet absorber (d31), hindered amine light stabilizer (d32), and silica particle bonding raw material silica particles, hydroxyl group-containing acrylic resin (d2), and ultraviolet absorber (d31) ) and/or a hindered amine light stabilizer (d32), a silica particle (D) dispersion can be obtained. The mode of bonding between the raw material silica particles and the hydroxyl group-containing acrylic resin (d2), the ultraviolet absorber (d31), and/or the hindered amine light stabilizer (d32) is as long as they are bonded by covalent bonds. Although there are no particular limitations, it may include, for example, combinations in the following embodiments (1), (2), and (3).
(1): The ultraviolet absorber (d31) and/or the hindered amine light stabilizer (d32) are bonded to the hydroxyl group-containing acrylic resin (d2), and such hydroxyl group-containing acrylic resin (d2) is Embodiment in which the ultraviolet absorber (d31) and/or hindered amine light stabilizer (d32) is bonded to the silica particles via the hydroxyl group-containing acrylic resin (d2),
(2): An embodiment in which the ultraviolet absorber (d31) and/or the hindered amine light stabilizer (d32) and the hydroxyl group-containing acrylic resin (d2) are each independently bonded to the silica particles,
(3): An embodiment in which the above (1) and (2) are combined, in which the ultraviolet absorber (d31) and/or the hindered amine light stabilizer (d32) are bonded to the hydroxyl group-containing acrylic resin (d2). and the hydroxyl group-containing acrylic resin (d2) is bonded to silica particles to which an ultraviolet absorber (d31) and/or a hindered amine light stabilizer (d32) is bonded,
can be mentioned.

In addition, when bonding the ultraviolet absorber (d31), the hindered amine light stabilizer (d32), and the hydroxyl group-containing acrylic resin (d2) to the silica particles, they may be modified with a silane coupling agent, etc. as necessary. Silica particles can be used.

The above aspects (1) to (3) will be explained below.

Embodiment (1): Embodiment in which the hydroxyl group-containing acrylic resin (d2) bound to the ultraviolet absorber (d31) and/or the hindered amine light stabilizer (d32) is bound to the silica particles.The silica particle (D) dispersion is , an embodiment in which the ultraviolet absorber (d31) and/or the hindered amine light stabilizer (d32) is bonded to the hydroxyl group-containing acrylic resin (d2), and the hydroxyl group-containing acrylic resin (d2) is bonded to the silica particles. can be obtained as a silica particle dispersion.

The silica particle (D) dispersion in this embodiment is, for example, prepared by combining silica particles (d1) having a polymerizable unsaturated group with a polymerizable unsaturated monomer to which a hydroxyl group-containing polymerizable unsaturated monomer and an ultraviolet absorber (d31) are bonded. And/or it can be obtained by reacting with a polymerizable unsaturated monomer mixture (d2-1) containing a polymerizable unsaturated monomer to which a hindered amine light stabilizer (d32) is bonded.

Silica particles having polymerizable unsaturated groups (d1)
Silica particles (d1) having a polymerizable unsaturated group can be obtained, for example, by mixing and heating raw material silica particles, an organic solvent, and a monomer having a polymerizable unsaturated group and a hydrolyzable silyl group. Silica particles having polymerizable unsaturated groups can be used. Further, it is also possible to use the silica particles (d1) having a polymerizable unsaturated group to which an amine is further added.

The organic solvent is preferably a hydrophilic organic solvent, and examples of the hydrophilic organic solvent include alcoholic organic solvents such as methanol, ethanol, isopropanol, n-butanol, and isobutanol; ethers such as dioxane and tetrahydrofuran. Organic solvents: ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono n-propyl ether, ethylene glycol monoisopropyl ether, ethylene glycol mono n-butyl ether, ethylene glycol monoisobutyl ether, ethylene glycol mono tert-butyl ether, diethylene glycol Monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, diethylene glycol monoisopropyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol monoisobutyl ether, diethylene glycol mono-tert-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol Glycol ether organic solvents such as mono-n-propyl ether, propylene glycol monoisopropyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol monoisopropyl ether; ethyl acetate , butyl acetate, isobutyl acetate, 3-methoxybutyl acetate, and other ester organic solvents, which can be used alone or in combination of two or more.

As the organic solvent, alcohols and/or glycol ethers are preferable. Among these, alcohols having a boiling point of 64 to 132°C, particularly 82 to 118°C, and glycol ethers having a boiling point of 120 to 208°C, particularly 120 to 192°C, are more preferable, and those having 2 carbon atoms are preferred. More preferred are alcohols having 1 to 8 carbon atoms, especially 3 to 5 carbon atoms, and glycol ethers having 3 to 5 carbon atoms, especially 3 to 4 carbon atoms.

The monomer having a polymerizable unsaturated group and a hydrolyzable silyl group is, for example, 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 2-(meth)acryloyloxy Ethyltrimethoxysilane, 2-(meth)acryloyloxyethyltriethoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, 2-(meth)acryloyloxyethylmethyldimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane , allyltrimethoxysilane, allyltriethoxysilane, a polymerizable unsaturated group obtained by reacting a functional group other than the hydrolyzable silyl group of various silane coupling agents with a functional group other than the unsaturated group of an unsaturated compound. and monomers having a hydrolyzable silyl group.

The silica particles (d1) having a polymerizable unsaturated group are obtained by heating and mixing raw silica particles, an organic solvent, and a monomer having a polymerizable unsaturated group and a hydrolyzable silyl group. More specifically, raw silica particles dispersed in a dispersion medium, an organic solvent, and a monomer having a polymerizable unsaturated group and a hydrolyzable silyl group are mixed, and from this mixture, the organic solvent and the dispersion medium for the silica particles are mixed. (including lower alcohols produced by hydrolyzing monomers having polymerizable unsaturated groups and hydrolyzable silyl groups) is azeotropically distilled under normal pressure or reduced pressure, and the dispersion medium is replaced with the above organic solvent. It can be produced by carrying out a dehydration condensation reaction under heating while or after substitution.

The nonvolatile concentration of the dispersion during the reaction is preferably in the range of about 5 to about 50% by weight. When the nonvolatile content concentration is less than about 5% by mass, that is, when the solvent exceeds about 95% by mass, the reaction time between the silica particles and the monomer having a polymerizable unsaturated group and a hydrolyzable silyl group becomes long, resulting in a decrease in production efficiency. There are cases. On the other hand, if the nonvolatile content concentration exceeds about 50% by mass, there is a risk that the product will gel.

By these manufacturing methods, the silicon atoms on the surface of the raw material silica particles and the silicon atoms of the monomer having a polymerizable unsaturated group and a hydrolyzable silyl group are bonded via an oxygen atom, and a siloxane bond is formed. It is possible to obtain a dispersion of silica particles (d1) having a polymerizable unsaturated group, in which the silica particles and a monomer having a polymerizable unsaturated group and a hydrolyzable silyl group are chemically bonded.

The blending ratio of the monomer having a polymerizable unsaturated group and a hydrolyzable silyl group when obtaining the above-mentioned silica particles (d1) having a polymerizable unsaturated group is 0.2 parts by mass with respect to 100 parts by mass of silica particles. It is preferably within the range of ~95 parts by mass, more preferably within the range of 0.5 parts by mass to 50 parts by mass, even more preferably within the range of 1.0 parts by mass to 20 parts by mass. . If the proportion of the monomer having a polymerizable unsaturated group and a hydrolyzable silyl group is less than 0.2 parts by mass, the produced silica particles (d1) having a polymerizable unsaturated group will be unstable in the dispersion medium. It may be inferior. If the proportion of the monomer having a polymerizable unsaturated group and a hydrolyzable silyl group is more than 95 parts by mass, the monomer having a polymerizable unsaturated group and a hydrolyzable silyl group will remain unreacted in the reaction with the raw material silica particles. It may remain.

In addition, when obtaining silica particles (d1) having a polymerizable unsaturated group, if necessary, an alkoxysilane having an alkyl group having 1 or more carbon atoms is added to the silica particles having a polymerizable unsaturated group and a hydrolyzable silyl group. The raw material silica particles may be reacted with the monomer. By reacting an alkoxysilane having an alkyl group with one or more carbon atoms, the water resistance of the resulting coating film may be improved. Examples of the alkoxysilane having an alkyl group having one or more carbon atoms include methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, and dodecyltrimethoxysilane. Examples include silane and the like, as well as compounds in which the methoxy group in these exemplified compounds is replaced with an ethoxy group (eg, methyltriethoxysilane).

As the dispersion of silica particles (d1) having polymerizable unsaturated groups, polymerizable unsaturated groups obtained by adding an amine are used from the viewpoints of storage stability and contamination removability of the formed coating film after outdoor exposure. It is preferable to use a dispersion of silica particles (d1) having a saturated group, and more preferably a dispersion of silica particles (d1) having a polymerizable unsaturated group obtained by adding a tertiary amine.

The above-mentioned tertiary amine may be used without particular restriction as long as it has a molecular weight of 120 to 380, preferably 130 to 350, more preferably 150 to 300, and has an alkyl group and/or aryl group at the end. I can do it. The tertiary amine is preferably an alkyl group in which at least one of the alkyl groups possessed by the tertiary amine has 3 or more carbon atoms, preferably 4 to 12 carbon atoms, and more preferably 5 to 10 carbon atoms, from the viewpoint of storage properties and the like. It is. Among these, from the viewpoint of storage properties and the like, it is particularly preferable that at least one of the alkyl groups possessed by the tertiary amine is a linear alkyl group.

Examples of the above tertiary amine include linear tertiary amines such as tripropylamine, tributylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, and tri-n-octylamine; Branched tertiary amines such as branched tritridecylamine such as triisopropylamine, triisobutylamine, and tri-2-ethylhexylamine; dimethyloctylamine, dimethyldodecylamine, dimethyloctadecylamine, hexyldiethylamine, octyldiethylamine, diethyldodecylamine, etc. Tertiary amines having mixed hydrocarbon groups; alicyclic tertiary amines such as dimethylcyclohexylamine and tricyclohexylamine; tertiary amines having aromatic ring substituents such as dimethylbenzylamine and tribenzylamine; and the like. One type or a combination of two or more types of these may be used.

A conventionally known method can be used to add the tertiary amine to the dispersion of silica particles (d1) having polymerizable unsaturated groups. The amount of the tertiary amine to be used is determined from the viewpoint of storage stability and contamination removability after outdoor exposure of the coating film formed when it is blended into the paint, etc. It is preferably within the range of 0.1 to 5.0 parts by mass, more preferably within the range of 1.5 to 3.0 parts by mass, based on 100 parts by mass of the solid content of d1). More preferably, the amount is 7 to 2.5 parts by mass.

A polymerizable unsaturated monomer to which the silica particles (d1) having a polymerizable unsaturated group obtained above are combined with a hydroxyl group-containing polymerizable unsaturated monomer and an ultraviolet absorber (d31) as at least a part of its components. and a polymerizable unsaturated monomer mixture (d2-1) containing at least one polymerizable unsaturated monomer selected from polymerizable unsaturated monomers to which a hindered amine light stabilizer (d32) is bonded. A silica particle dispersion (D) is obtained in which a hydroxyl group-containing acrylic resin (d2) to which an absorber (d31) and/or a hindered amine light stabilizer (d32) is bonded is bonded to silica particles. The polymerizable unsaturated monomer mixture (d2-1) will be explained below.

Polymerizable unsaturated monomer mixture (d2-1)
The polymerizable unsaturated monomer mixture (d2-1) to be subjected to the reaction with the silica particles (d1) having a polymerizable unsaturated group contains, as at least a part of its components, a hydroxyl group-containing polymerizable unsaturated monomer, and It contains at least one polymerizable unsaturated monomer selected from a polymerizable unsaturated monomer to which an ultraviolet absorber (d31) is bonded and a polymerizable unsaturated monomer to which a hindered amine light stabilizer (d32) is bonded.

As the hydroxyl group-containing polymerizable unsaturated monomer, the hydroxyl group-containing polymerizable unsaturated monomer described in relation to the hydroxyl group-containing acrylic resin (d2) can be used.

Further, other polymerizable unsaturated monomers copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer may be added to the polymerizable unsaturated monomer mixture (d2-1). Examples of such other polymerizable unsaturated monomers include specific examples of compounds having one or more polymerizable unsaturated groups in one molecule (1) described in relation to the hydroxyl group-containing acrylic resin (A1). ) to (8) can be mentioned.

Other polymerizable unsaturated monomers that can be copolymerized with the above-mentioned hydroxyl group-containing polymerizable unsaturated monomers include alkoxysilyl group-containing polymerizable monomers from the viewpoint of stain removability and curability of the formed coating film after outdoor exposure. Preferably, it contains unsaturated monomers.

Since the polymerizable unsaturated monomer mixture (d2-1) contains the alkoxysilyl group-containing polymerizable unsaturated monomer, in addition to the crosslinking between the hydroxyl group and the crosslinking agent (B), the condensation reaction between the alkoxylyl groups and the alkoxy Since a crosslinking bond is generated by the reaction between a silyl group and a hydroxyl group, it is possible to improve the stain removability and curability of the formed coating film after outdoor exposure.

As the alkoxysilyl group-containing polymerizable unsaturated monomer, for example, the alkoxysilyl group-containing polymerizable unsaturated monomer described in relation to the hydroxyl group-containing acrylic resin (A1) can be used.

When the polymerizable unsaturated monomer mixture (d2-1) contains the alkoxysilyl group-containing polymerizable unsaturated monomer, its formulation is determined from the viewpoint of stain removability and curability of the formed coating film after outdoor exposure. The proportion is preferably within the range of 3 to 60% by mass, more preferably within the range of 5 to 55% by mass, based on the total amount of the polymerizable unsaturated monomer mixture (d2-1), and is more preferably within the range of 5 to 55% by mass. It is more preferably within the range of 50% by mass.

Other polymerizable unsaturated monomers copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer may include polysiloxane chain-containing polymerizable unsaturated monomers from the viewpoint of stain removability of the formed coating film. preferable.

As the polysiloxane chain-containing polymerizable unsaturated monomer, for example, the polysiloxane chain-containing polymerizable unsaturated monomer described in relation to the hydroxyl group-containing acrylic resin (A1) can be used.

When the polymerizable unsaturated monomer mixture (d2-1) contains the polysiloxane chain-containing polymerizable unsaturated monomer, from the viewpoint of stain removability of the formed coating film, etc., the proportion of the polymerizable unsaturated monomer is It is preferably within the range of 0.5 to 40% by mass, more preferably within the range of 1 to 30% by mass, and 1.5 to 20% by mass based on the total amount of the monomer mixture (d2-1). More preferably, it is within the range of .

As the polymerizable unsaturated monomer to which the ultraviolet absorber (d31) is bonded, an ultraviolet absorber having a polymerizable unsaturated group can be used, and a commercially available product is, for example, "RUVA-93" (manufactured by Otsuka Chemical Co., Ltd., trade name: ) etc. can be suitably used.

In addition, examples of the polymerizable unsaturated monomer to which the ultraviolet absorber (d31) is bonded include a polymerizable unsaturated monomer having a reactive group, and an ultraviolet absorber having a functional group capable of reacting with the reactive group. It can be obtained by reacting. Specifically, for example, the ultraviolet absorber (d31) is bonded by reacting a polymerizable unsaturated monomer having an isocyanate group with an ultraviolet absorber having an active hydrogen group such as a hydroxyl group or an amino group, preferably a hydroxyl group. A polymerizable unsaturated monomer can be obtained.

Furthermore, as the polymerizable unsaturated monomer to which the hindered amine light stabilizer (d32) is bonded, a hindered amine light stabilizer having a polymerizable unsaturated group can be used. LA-82'', ``ADK STAB LA-87'' (manufactured by ADEKA Co., Ltd., trade name, ADEKA STAB is a registered trademark), etc. can be suitably used.

In addition, examples of the polymerizable unsaturated monomer to which the hindered amine light stabilizer (d32) is bonded include a polymerizable unsaturated monomer having a reactive group and a functional group capable of reacting with the reactive group. It can be obtained by reacting with a hindered amine light stabilizer. Specifically, for example, by reacting a polymerizable unsaturated monomer having an isocyanate group with a hindered amine light stabilizer having an active hydrogen group such as a hydroxyl group or an amino group, preferably a hydroxyl group, a hindered amine type light stabilizer can be produced. A polymerizable unsaturated monomer to which a light stabilizer (d32) is bonded can be obtained.

The proportion of the hydroxyl group-containing polymerizable unsaturated monomer in the polymerizable unsaturated monomer mixture (d2-1) is within the range of 4.5 to 60% by mass based on the total amount of the polymerizable unsaturated monomer mixture (d2-1). It is preferably within the range of 10 to 50% by weight, even more preferably 15 to 45% by weight.

When the polymerizable unsaturated monomer mixture (d2-1) contains a polymerizable unsaturated monomer bound to an ultraviolet absorber (d31), from the viewpoint of stain removal properties of the formed coating film, etc., the blending ratio is as follows: It is preferably within the range of 0.5 to 40% by mass, more preferably within the range of 1 to 20% by mass, and 1 to 15% by mass based on the total amount of the polymerizable unsaturated monomer mixture (d2-1). It is more preferable that the amount is within the range of % by mass.

In addition, when the polymerizable unsaturated monomer mixture (d2-1) contains a polymerizable unsaturated monomer bound to a hindered amine light stabilizer (d32), from the viewpoint of stain removability of the formed coating film, etc. The blending ratio thereof is preferably within the range of 0.5 to 40% by mass, more preferably within the range of 1 to 20% by mass, based on the total amount of the polymerizable unsaturated monomer mixture (d2-1). It is preferably in the range of 1 to 15% by mass, and more preferably in the range of 1 to 15% by mass.

Furthermore, the total proportion of the polymerizable unsaturated monomer to which the ultraviolet absorber (d31) is bonded and the polymerizable unsaturated monomer to which the hindered amine light stabilizer (d32) is bonded in the polymerizable unsaturated monomer mixture (d2-1). is preferably within the range of 0.5 to 40% by mass, more preferably within the range of 1 to 40% by mass, based on the total amount of the polymerizable unsaturated monomer mixture (d2-1), and It is more preferably within the range of 35% by mass.

In addition, the hydroxyl value of the hydroxyl group-containing acrylic resin (d2) produced from the polymerizable unsaturated monomer mixture (d2-1) is 20 to It is preferably within the range of 215 mgKOH/g, more preferably within the range of 40 to 200 mgKOH/g, and even more preferably within the range of 60 to 170 mgKOH/g.

Formation of silica particle (D) dispersion The silica particle (D) dispersion is made by combining the silica particles (d1) having the polymerizable unsaturated group and the polymerizable unsaturated monomer mixture (d2-1) in the presence of a solvent. It can be obtained by carrying out a polymerization reaction as described below. The polymerization method is not particularly limited, and any known polymerization method can be used, but in particular, polymerization is carried out in an organic solvent in the presence of an appropriate catalyst, polymerization initiator, etc. A solution polymerization method can be preferably used.

Examples of the organic solvent used in the above solution polymerization method include benzene, toluene, xylene, ethylbenzene, "Swazol 1000", "Swazol 1500" (trade name, manufactured by Maruzen Petrochemical Co., Ltd., high boiling point petroleum solvent), etc. Aromatic compounds, hydrocarbon solvents such as pentane, hexane, heptane, octane, cyclohexane, cycloheptane, mineral spirit; halogenated hydrocarbons such as trichlorethylene, tetrachlorethylene; ethyl acetate, n-butyl acetate, isobutyl acetate Ester solvents such as , ethyl propionate, methyl cellosolve acetate, butyl carbitol acetate, ethylene glycol monomethyl ether acetate, diethylene glycol monobutyl ether acetate, ethyl 3-ethoxypropionate; ketones such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, etc. Alcohol-based solvents such as methanol, ethanol, isopropanol, n-butanol, sec-butanol, isobutanol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether; n-butyl ether, dioxane, Examples include ether solvents such as dibutyl ether and ethylene glycol dimethyl ether; dimethyl sulfoxide, dimethyl formamide, N-methylpyrrolidone, and water. These organic solvents can be used alone or in combination of two or more. Among these, aromatic solvents and ester solvents are preferred from the viewpoint of the appearance of the formed coating film, and ester solvents are more preferred.

The polymerization initiator that can be used in the above polymerization is not particularly limited, and examples include benzoyl peroxide, paramenthane hydroperoxide, cumene hydroperoxide, lauroyl peroxide, cyclohexanone peroxide, 3,3,5-trimethyl Cyclohexanone peroxide, methylcyclohexanone peroxide, tert-butylperoxypivalate, 1,1'-bis(tert-butylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)-3,3,5 -Trimethylcyclohexane, n-butyl-4,4-bis(tert-butylperoxy)valerate, 2,2'-di(tert-butylperoxy)butane, tert-butylhydroxyperoxide, 2,5-dimethylhexane -2,5-dihydroperoxide, di-tert-butyl peroxide, di-n-propyl peroxydicarbonate, tert-hexyl peroxy-2-ethylhexanoate, 1,3-bis(tert-butyl peroxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, diisopropylbenzene peroxide, tert-butylcumyl peroxide, decanoyl peroxide, lauroyl peroxide, Benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, bis(tert-butylcyclohexyl) peroxydicarbonate, tert-butylperoxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, Peroxide polymerization initiator such as hydrogen peroxide; 1,1-azobis(cyclohexane-1-carbonitrile), azocumene, 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2' -Azobis(2-methylbutyronitrile), 2,2'-azobisisobutyronitrile, 2,2'-azobis-(4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2,2'-azobis (2-methylpropionate), 2,2'-di(2-hydroxyethyl)azobisisobutyronitrile, 4,4'-azobis(4-cyanovaleric acid), 2-(tert-butylazo)- 2-cyanopropane, 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(2-methylpropane), dimethyl 2,2'-azobis(2-methylpropionate) , 2,2'-azobis-(N-butyl-2-methylpropionamide) and other azo polymerization initiators; persulfate-based initiators such as potassium persulfate and sodium persulfate; peroxide and reducing agent. Examples include radical polymerization initiators known per se, such as redox type initiators.

The amount of the radical polymerization initiator used is preferably in the range of 0.1 to 20 parts by mass, and 1 to 10 parts by mass, based on 100 parts by mass of the polymerizable unsaturated monomer mixture (d2-1). It is more preferable. If the amount of the radical polymerization initiator is less than 0.1 parts by mass, the proportion of unreacted polymerizable unsaturated monomers that do not react with the silica particles (d1) having polymerizable unsaturated groups may increase. If the amount of the radical polymerization initiator is more than 20 parts by mass, aggregation of particles may occur due to polymerization of silica particles to which the hydroxyl group-containing acrylic resin (d2) is bonded.

In addition, in the silica particle (D) dispersion, unreacted polymerizable unsaturated monomers or polymerizable unsaturated monomers that reacted with each other but did not react with the silica particles (d1) having a polymerizable unsaturated group It does not matter if the polymer contains other polymers. The mixing ratio of the silica particle (d1) dispersion having the polymerizable unsaturated group and the polymerizable unsaturated monomer mixture (d2-1) is determined from the viewpoint of stain removability after outdoor exposure of the formed coating film, etc. , the mass ratio is preferably within the range of (d1)/(d2-1) = 20/80 to 90/10, more preferably within the range of 30/70 to 80/20, and 40/60. More preferably, the ratio is within the range of 60/40.

When the reaction of the silica particles (d1) having a polymerizable unsaturated group and the polymerizable unsaturated monomer mixture (d2-1) is carried out in a solvent, the silica particles (d1) having a polymerizable unsaturated group and the polymerizable unsaturated monomer mixture (d2-1) The total mass concentration of the monomer mixture (d2-1) is preferably in the range of 10% by mass to 90% by mass, more preferably in the range of 20% by mass to 70% by mass. If the total mass concentration is less than 10% by mass, the reaction time may become longer and production efficiency may decrease. If the total mass concentration is higher than 90% by mass, the viscosity of the reaction system may become high and stirring may become difficult.

The reaction is preferably carried out with stirring while replacing the gas phase in the reaction vessel with an inert gas, from the viewpoint of suppressing inhibition of the polymerization reaction by oxygen and improving the reaction rate. The reaction temperature and reaction time can be appropriately selected depending on the type of polymerizable unsaturated monomer mixture (d2-1), etc., but the reaction temperature is preferably within the range of about 0°C to about 250°C. Preferably, the time is within the range of 1 to 72 hours. The reaction can usually be carried out under normal pressure, but can also be carried out under increased pressure or reduced pressure.

In the above reaction, the polymerization rate of the polymerizable unsaturated monomer mixture (d2-1) is preferably about 90% or more, more preferably about 95% or more. If the polymerization rate of the polymerizable unsaturated monomer mixture (d2-1) is less than about 90%, the stain removability of the formed coating film after outdoor exposure may be poor, and the resulting silica particles (D) When using the dispersion, odor caused by the unreacted polymerizable unsaturated monomer mixture (d2-1) may become a problem. The amount of unreacted polymerizable unsaturated monomer mixture (d2-1) can be reduced by extending the reaction time. If the amount of unreacted polymerizable unsaturated monomer mixture (d2-1) is small, it can be reduced by further carrying out the polymerization reaction by adding a radical polymerization initiator. Further, the solvent of the obtained silica particle (D) dispersion may be replaced with another solvent such as water, if desired.

In addition, the glass transition temperature Tg of the hydroxyl group-containing acrylic resin bonded to the silica particle (D) dispersion obtained by the above manufacturing method is determined from the viewpoint of stain removability after outdoor exposure of the formed coating film, etc. The temperature is preferably within the range of -40 to 40°C, and more preferably within the range of -30 to 30°C.

Embodiment (2): Embodiment in which the ultraviolet absorber (d31) and/or the hindered amine light stabilizer (d32) is bonded to the silica particles independently of the hydroxyl group-containing acrylic resin (d2) Silica particle (D) dispersion The body is obtained as a silica particle dispersion in which the ultraviolet absorber (d31) and/or the hindered amine light stabilizer (d32) are bonded to the silica particles independently of the hydroxyl group-containing acrylic resin (d2). You can also do it.

The silica particle (D) dispersion of this embodiment is, for example, a silica particle (d1' ), which contains a hydroxyl group-containing polymerizable unsaturated monomer and does not contain a polymerizable unsaturated monomer to which an ultraviolet absorber (d31) is bonded and a polymerizable unsaturated monomer to which a hindered amine light stabilizer (d32) is bonded. It can be obtained by reacting with a polymerizable unsaturated monomer mixture (d2-1').

Silica particles (d1') to which an ultraviolet absorber (d31) and/or hindered amine light stabilizer (d32) are bonded and have a polymerizable unsaturated group
The silica particles (d1') to which a UV absorber (d31) and/or a hindered amine light stabilizer (d32) are bonded and which have a polymerizable unsaturated group are, for example, UV absorbing groups and/or hindered amine light stabilizers (d32). It can be obtained by reacting a compound having an amine-based photostabilizing group and a hydrolyzable silyl group, and a monomer having a polymerizable unsaturated group and a hydrolyzable silyl group with raw material silica particles.

Examples of the compound having an ultraviolet absorbing group and/or a hindered amine photostabilizing group and a hydrolyzable silyl group include a silane coupling agent having a reactive group and a compound capable of reacting with this reactive group. It can be obtained by reacting an ultraviolet absorber and/or a hindered amine light stabilizer having a functional group. For example, by reacting a silane coupling agent having an isocyanate group with an ultraviolet absorber (d31) or a hindered amine light stabilizer (d32) having an active hydrogen group such as a hydroxyl group or an amino group, ultraviolet absorption can be achieved. A compound having a functional group and/or a hindered amine type photostabilizing group and a hydrolyzable silyl group can be obtained.

Examples of the silane coupling agent suitably used include 3-(trimethoxysilyl)propyl isocyanate, 3-(triethoxysilyl)propyl isocyanate, and the like. In addition, commercially available products include, for example, "SILIQUEST A-Link25" or "SILIQUEST A-Link35" (manufactured by Momentive Performance Materials, trade name, SILIQUEST is a trademark. A silane coupling agent having an isocyanate group.), "KBE- 9007N" (manufactured by Shin-Etsu Silicone Co., Ltd., trade name, 3-(triethoxysilyl)propyl isocyanate).

In addition, examples of the UV absorber (d31) or hindered amine light stabilizer (d32) that can be suitably used include, for example, an ultraviolet absorber (d31) having a hydroxyl group or a hindered amine light stabilizer (d32). Stabilizers (d32) and the like can be mentioned. In addition, commercially available products include, for example, "TinuvinPS", "Tinuvin99-2", "Tinuvin326", "Tinuvin384-2", "Tinuvin900", "Tinuvin928", "Tinuvin1130", "Tinuvin400", "Tinuvin in405”, “ "Tinuvin460", "Tinuvin477", "Tinuvin479", "UVA-903KT", "UVA-935LH" (manufactured by BASF, product name, Tinuvin is a registered trademark. Ultraviolet absorber with hydroxy group.), "Tinuvin111FDL" , "Tinuvin 144", "Tinuvin 152" (same as a hindered amine light stabilizer having a hydroxy group), and the like.

Moreover, commercially available products can also be used as such compounds having an ultraviolet absorbing group and/or a hindered amine photostabilizing group and a hydrolyzable silyl group. Examples of such commercial products include "TMPS-E" (manufactured by Shin-Etsu Silicone Co., Ltd., a hindered amine photostabilizing group-containing silane).

A compound having an ultraviolet absorbing group and/or a hindered amine photostabilizing group and a hydrolyzable silyl group as described above, and a monomer having a polymerizable unsaturated group and a hydrolyzable silyl group are added to the raw material silica particles. By reacting with, it is possible to obtain silica particles (d1') to which an ultraviolet absorber (d31) and/or a hindered amine light stabilizer (d32) are bonded and which have a polymerizable unsaturated group.

The monomer having a polymerizable unsaturated group and a hydrolyzable silyl group used to obtain the silica particles (d1') includes a polymerizable unsaturated group and a hydrolyzable silyl group used to obtain the silica (d1). Monomers similar to those having can be used.

A compound having an ultraviolet absorbing group and/or a hindered amine light stabilizing group and a hydrolyzable silyl group, and a monomer having a polymerizable unsaturated group and a hydrolyzable silyl group are reacted with raw silica particles. There are no particular limitations on the method, and any commonly used treatment method using a silane coupling agent can be appropriately selected. For example, a method may be mentioned in which a solution containing a compound having an ultraviolet absorbing group and/or a hindered amine photostabilizing group and a hydrolyzable silyl group is added to a slurry containing raw material silica particles and stirred. can.

Polymerizable unsaturated monomer mixture (d2-1')
By reacting the silica particles (d1') obtained as described above with a polymerizable unsaturated monomer mixture (d2-1') containing a hydroxyl group-containing polymerizable unsaturated monomer as at least a part of its components, A silica particle (D) dispersion can be obtained.

The polymerizable unsaturated monomer mixture (d2-1') contains a polymerizable unsaturated monomer bound to an ultraviolet absorber (d31) and a polymerizable unsaturated monomer bound to a hindered amine light stabilizer (d32). do not have.

The hydroxyl group-containing polymerizable unsaturated monomer contained in the polymerizable unsaturated monomer mixture (d2-1') is the same hydroxyl group-containing polymerizable unsaturated monomer as that used in the polymerizable unsaturated monomer mixture (d2-1). Monomers can be used. In addition, the polymerizable unsaturated monomer mixture (d2-1') includes other polymerizable unsaturated monomers that can be copolymerized with the hydroxyl group-containing polymerizable unsaturated monomer, similar to the polymerizable unsaturated monomer mixture (d2-1). Monomers may also be added.

Other polymerizable unsaturated monomers that can be copolymerized with the above-mentioned hydroxyl group-containing polymerizable unsaturated monomers include alkoxysilyl group-containing polymerizable monomers from the viewpoint of stain removability and curability of the formed coating film after outdoor exposure. Preferably, it contains unsaturated monomers.

Since the polymerizable unsaturated monomer mixture (d2-1') contains the above-mentioned alkoxysilyl group-containing polymerizable unsaturated monomer, in addition to the crosslinking between the hydroxyl group and the crosslinking agent (B), the condensation reaction between the alkoxylyl groups and Since a crosslinking bond is generated by the reaction between an alkoxysilyl group and a hydroxyl group, it is possible to improve the stain removability and curability of the formed coating film after outdoor exposure.

As the alkoxysilyl group-containing polymerizable unsaturated monomer, for example, the alkoxysilyl group-containing polymerizable unsaturated monomer described in relation to the hydroxyl group-containing acrylic resin (A1) can be used.

When the polymerizable unsaturated monomer mixture (d2-1') contains the alkoxysilyl group-containing polymerizable unsaturated monomer, from the viewpoint of stain removability and curability of the formed coating film after outdoor exposure, its The blending ratio is preferably within the range of 3 to 60% by mass, more preferably within the range of 5 to 55% by mass, based on the total amount of the polymerizable unsaturated monomer mixture (d2-1'), It is more preferably within the range of 5 to 50% by mass.

Other polymerizable unsaturated monomers copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer may include polysiloxane chain-containing polymerizable unsaturated monomers from the viewpoint of stain removability of the formed coating film. preferable.

As the polysiloxane chain-containing polymerizable unsaturated monomer, for example, the polysiloxane chain-containing polymerizable unsaturated monomer described in relation to the hydroxyl group-containing acrylic resin (A1) can be used.

When the polymerizable unsaturated monomer mixture (d2-1') contains the polysiloxane chain-containing polymerizable unsaturated monomer, from the viewpoint of stain removability of the formed coating film, etc., the proportion of the polymerizable unsaturated monomer mixture (d2-1') It is preferably within the range of 0.5 to 40% by mass, more preferably within the range of 1 to 30% by mass, and 1.5 to 20% by mass based on the total amount of the saturated monomer mixture (d2-1'). It is more preferable that the amount is within the range of % by mass.

The proportion of the hydroxyl group-containing polymerizable unsaturated monomer in the polymerizable unsaturated monomer mixture (d2-1') is in the range of 4.5 to 60% by mass based on the total amount of the polymerizable unsaturated monomer mixture (d2-1'). It is preferably within the range of 10 to 50% by mass, more preferably within the range of 15 to 45% by mass.

In addition, the hydroxyl value of the hydroxyl group-containing acrylic resin (d2) produced from the polymerizable unsaturated monomer mixture (d2-1') is 20 It is preferably in the range of ~215 mgKOH/g, more preferably in the range of 40 to 200 mgKOH/g, even more preferably in the range of 60 to 170 mgKOH/g.

Formation of silica particle (D) dispersion The silica particle (D) dispersion has the above-mentioned ultraviolet absorber (d31) and/or hindered amine light stabilizer (d32) bonded thereto, and has a polymerizable unsaturated group. It can be obtained by subjecting the silica particles (d1') and the polymerizable unsaturated monomer mixture (d2-1') to a polymerization reaction in the presence of a solvent. The polymerization method is not particularly limited, and for example, a polymerization method similar to the polymerization reaction of silica particles having a polymerizable unsaturated group (d1) and a polymerizable unsaturated monomer mixture (d2-1) is used. be able to.

Silica particles (d1') to which the ultraviolet absorber (d31) and/or hindered amine light stabilizer (d32) are bonded and have a polymerizable unsaturated group, and the polymerizable unsaturated monomer mixture (d2- 1'), the mass ratio of (d1')/(d2-1') = 20/80 to 90/10 from the viewpoint of contamination removability after outdoor exposure of the formed coating film, etc. It is preferably within the range, more preferably within the range of 30/70 to 80/20, and even more preferably within the range of 40/60 to 60/40.

In addition, the glass transition temperature Tg of the hydroxyl group-containing acrylic resin (d2) bonded to the silica particle (D) dispersion obtained by the above production method is determined by the contamination removability of the formed coating film after outdoor exposure. From this point of view, the temperature is preferably within the range of -40 to 40°C, and more preferably within the range of -30 to 30°C.

Embodiment (3): An embodiment in which the above embodiments (1) and (2) are combined. Raw material silica particles, hydroxyl group-containing acrylic resin (d2), ultraviolet absorber (d31) and/or hindered amine light stabilizer ( The embodiment of the bonding with d32) is a combination of the above embodiments (1) and (2), in which the ultraviolet absorber (d31) and/or the hindered amine light stabilizer (d32) contains a hydroxyl group. An embodiment in which the acrylic resin (d2) is bonded, and the hydroxyl group-containing acrylic resin (d2) is bonded to silica particles to which an ultraviolet absorber (d31) and/or a hindered amine light stabilizer (d32) is bonded. It may be.

The silica particle (D) dispersion of this embodiment is, for example, the one described in relation to the above embodiment (2) in which "the ultraviolet absorber (d31) and/or the hindered amine light stabilizer (d32) are bonded, and the polymerizable non-polymerizable The silica particles having a saturated group (d1') are replaced with the hydroxyl group-containing polymerizable unsaturated monomer and the ultraviolet absorber (d31) bonded polymerizable unsaturated monomer and/or hindered amine explained in relation to the above aspect (1). It can be obtained by reacting with a polymerizable unsaturated monomer mixture (d2-1) containing a polymerizable unsaturated monomer to which a light stabilizer (d32) is bonded. Selection of each component, reaction conditions, etc. can be carried out in accordance with the detailed explanation regarding the above aspects (1) and (2).

The content of the silica particle (D) dispersion to which the hydroxyl group-containing acrylic resin (d21) is bound, and the ultraviolet absorber (d31) and/or hindered amine light stabilizer (d32) is From the viewpoint of the contamination removability of the membrane, the contamination removability after outdoor exposure, transparency, water resistance, finished appearance, etc., 0 based on 100 parts by mass of the total solid content of the hydroxyl group-containing resin (A) and the crosslinking agent (B). It is preferably within the range of .1 to 25 parts by weight, more preferably within the range of 0.5 to 20 parts by weight, and even more preferably within the range of 1 to 15 parts by weight.

Coating composition The hydroxyl group-containing resin (A) obtained as above, the crosslinking agent (B), the reactive functional group-containing organopolysiloxane (C), and the hydroxyl group-containing acrylic resin (d21) are combined, and The coating composition of the present invention can be obtained by mixing a dispersion of silica particles (D) bound with an ultraviolet absorber (d31) and/or a hindered amine light stabilizer (d32).

The coating composition of the present invention may further contain resins other than the hydroxyl group-containing resin (A), coloring pigments, glitter pigments, dyes, etc., as necessary, and may further contain extender pigments, ultraviolet absorbers, light absorbers, etc. A stabilizer, a catalyst, an antifoaming agent, a viscosity modifier, a rust preventive agent, a surface modifier, an organic solvent, etc. can be contained as appropriate.

Examples of resins other than the hydroxyl group-containing resin (A) include, for example, acrylic resins that do not contain hydroxyl groups, polyester resins that do not contain hydroxyl groups, polyurethane resins that do not contain hydroxyl groups, and polyether resins that do not contain hydroxyl groups.

Examples of the coloring pigment include titanium oxide, zinc white, carbon black, cadmium red, molybdenum red, chrome yellow, chromium oxide, Prussian blue, cobalt blue, azo pigment, phthalocyanine pigment, quinacridone pigment, isoindoline pigment, and threne pigment. , perylene pigments, and the like.

Examples of the glittering pigment include aluminum pigments, mica pigments, mica pigments coated with titanium oxide, aluminum oxide pigments coated with titanium oxide, and the like.

Examples of the extender pigment include talc, clay, kaolin, baryta, barium sulfate, barium carbonate, calcium carbonate, and alumina white.

Each of the above pigments can be used alone or in combination of two or more.

When the coating composition of the present invention is used as a clear coating and contains a pigment, the amount of the pigment is preferably an amount that does not impede the transparency of the resulting coating, For example, it is preferably within the range of 0.1 to 20% by mass, more preferably within the range of 0.3 to 10% by mass, and 0.5 to 10% by mass, based on the total solid content in the coating composition. It is more preferably within the range of 5% by mass.

Further, when the coating composition of the present invention is used as a colored coating and contains a pigment, the amount of the pigment blended is 1 to 200% by mass based on the total solid content in the coating composition. It is preferably within the range, more preferably within the range of 2 to 100% by mass, and even more preferably within the range of 5 to 50% by mass.

As used herein, "solids" refers to nonvolatile components such as resins, crosslinking agents, and pigments contained in a coating composition that remain after drying the coating composition at 110° C. for 1 hour. For this reason, for example, the total solid content of the coating composition is determined by weighing the coating composition into a heat-resistant container such as an aluminum foil cup, spreading the coating composition on the bottom of the container, and then drying it at 110 ° C. for 1 hour. It can be calculated by weighing the mass of the components in the coating composition remaining after drying and determining the ratio of the mass of the components remaining after drying to the total mass of the coating composition before drying.

As the ultraviolet absorber, conventionally known ones can be used, such as ultraviolet absorbers such as benzotriazole absorbers, triazine absorbers, salicylic acid derivative absorbers, and benzophenone absorbers. I can do it. These can be used alone or in combination of two or more.

Specific examples of the benzotriazole absorbent include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-5'-t-butylphenyl)benzotriazole, 2- (2'-hydroxy-3',5'-di-t-butylphenyl)benzotriazole, 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-t-amylphenyl)benzo Triazole, 2-(2'-hydroxy-4'-octoxyphenyl)benzotriazole, 2-{2'-hydroxy-3'-(3'',4'',5'',6''-tetrahydrophthalimide Examples include methyl)-5'-methylphenyl}benzotriazole, 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, and the like.

Specific examples of the triazine-based absorbent include 2,4-bis(2,4-dimethylphenyl)-6-(2-hydroxy-4-isooctyloxyphenyl)-1,3,5-triazine, 2- [4((2-hydroxy-3-dodecyloxypropyl)-oxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[ 4-((2-hydroxy-3-tridecyloxypropyl)-oxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2- Examples include (2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine.

Specific examples of the salicylic acid derivative absorbent include phenyl salicylate, p-octylphenyl salicylate, 4-tert-butylphenyl salicylate, and the like.

Specific examples of the benzophenone absorbent include 4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, and 2-hydroxy-4-methoxy-2'-carboxybenzophenone. , 2-hydroxy-4-methoxy-5-sulfobenzophenone trihydrate, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-octade Siloxybenzophenone, sodium 2,2'-dihydroxy-4,4'-dimethoxy-5-sulfobenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 5-chloro- 2-hydroxybenzophenone, resorcinol monobenzoate, 2,4-dibenzoylresorcinol, 4,6-dibenzoylresorcinol, hydroxydodecylbenzophenone, 2,2'-dihydroxy-4(3-methacryloxy-2-hydroxypropoxy)benzophenone, etc. can be mentioned.

Further, as commercial products of the ultraviolet absorber, for example, "TINUVIN 900", "TINUVIN 928", "TINUVIN 384-2", "TINUVIN 479", "TINUVIN 405", "TINUVIN 400", (manufactured by BASF) , trade name, TINUVIN is a registered trademark), "RUVA 93" (manufactured by Otsuka Chemical Co., Ltd., trade name), and the like.

When the coating composition of the present invention contains an ultraviolet absorber, the amount of the ultraviolet absorber to be blended is preferably in the range of 0.1 to 10% by mass based on the total solid content in the coating composition. It is preferably in the range of 0.2 to 5% by weight, more preferably in the range of 0.3 to 3% by weight.

As the light stabilizer, conventionally known ones can be used, and examples thereof include hindered amine light stabilizers.

Examples of the above-mentioned hindered amine compounds include bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis(N -Methyl-2,2,6,6-tetramethyl-4-piperidinyl) sebacate, 4-benzoyloxy-2,2',6,6'-tetramethylpiperidine, bis(1,2,2,6,6 Monomer types such as -pentamethyl-4-piperidyl) {[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl}butylmalonate; poly{[6-(1,1, 3,3-tetramethylbutyl)imino-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2 , 6,6-tetramethyl-4-piperidyl)iminol]; oligomer-type products such as 4-hydroxy-2,2,6,6-tetramethyl-1-piperidine ethanol and succinic acid, etc. Examples include polyester bond type.

Examples of commercially available light stabilizers include "TINUVIN 123," "TINUVIN 152," "TINUVIN 292" (manufactured by BASF, trade name, TINUVIN is a registered trademark), and "HOSTAVIN 3058" (manufactured by Clariant, trade name). Examples include "Adeka Stab LA-82" (manufactured by ADEKA Co., Ltd., trade name, Adeka Stab is a registered trademark).

When the coating composition of the present invention contains a light stabilizer, the amount of the light stabilizer is within the range of 0.1 to 10% by mass based on the total solid content in the coating composition. It is preferably in the range of 0.2 to 5% by mass, more preferably in the range of 0.3 to 3% by mass.

As the catalyst, conventionally known ones can be used. For example, when the coating composition of the present invention contains the polyisocyanate compound and/or blocked polyisocyanate compound as the crosslinking agent (B). The coating composition of the present invention may contain a urethanization reaction catalyst.

Specific examples of the urethanization reaction catalyst include tin octylate, dibutyltin diacetate, dibutyltin di(2-ethylhexanoate), dibutyltin dilaurate, dioctyltin diacetate, and dioctyltin di(2-ethylhexanoate). -ethylhexanoate), dibutyltin oxide, dibutyltin sulfide, dioctyltin oxide, dibutyltin fatty acid salt, lead 2-ethylhexanoate, zinc octylate, zinc naphthenate, zinc fatty acids, bismuth octoate, 2-ethyl Organometallic compounds such as bismuth hexanoate, bismuth oleate, bismuth neodecanoate, bismuth versatate, bismuth naphthenate, cobalt naphthenate, calcium octylate, copper naphthenate, and tetra(2-ethylhexyl) titanate; tertiary amines, etc. These can be used alone or in combination of two or more.

When the coating composition of the present invention contains the above-mentioned urethanization reaction catalyst, the amount of the urethanization reaction catalyst is in the range of 0.005 to 2% by mass based on the total solid content of the coating composition of the present invention. It is preferably within the range of 0.01 to 1% by mass, and more preferably within the range of 0.01 to 1% by mass.

In addition, when the coating composition of the present invention contains the above-mentioned urethanization reaction catalyst, from the viewpoint of storage stability, curability, etc., the coating composition of the present invention may contain acetic acid, propionic acid, butyric acid, isopentanoic acid, hexanoic acid, 2-ethylbutyric acid, naphthenic acid, octylic acid, nonanoic acid, decanoic acid, 2-ethylhexanoic acid, isooctanoic acid, isononanoic acid, lauric acid, palmitic acid, stearic acid, oleic acid, linoleic acid, neodecanoic acid, versatic acid, Organic acids such as isobutyric anhydride, itaconic anhydride, acetic anhydride, citraconic anhydride, propionic anhydride, maleic anhydride, butyric anhydride, citric acid anhydride, trimellitic anhydride, pyromellitic anhydride, phthalic anhydride; hydrochloric acid, phosphorus It may contain inorganic acids such as acids; metal coordinating compounds such as acetylacetone and imidazole compounds.

Further, when the coating composition of the present invention uses the melamine resin as the crosslinking agent (B), the coating composition of the present invention uses p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid as the curing catalyst. sulfonic acids such as monobutyl phosphoric acid, dibutyl phosphoric acid, mono(2-ethylhexyl) phosphoric acid, di(2-ethylhexyl) phosphoric acid, etc.; salts of these acids with amine compounds, etc. can.

When the coating composition of the present invention contains the curing catalyst for the melamine resin, the amount of the curing catalyst for the melamine resin is 0.1 to 2% by mass based on the total solid content of the coating composition of the present invention. It is preferably within the range of , more preferably within the range of 0.2 to 1.7 mass %, and even more preferably within the range of 0.3 to 1.4 mass %.

In a preferred embodiment, the coating composition of the present invention is an organic solvent type coating composition in which the solvent is mainly an organic solvent.

Examples of the organic solvent include toluene, xylene, aromatic solvents such as "Swasol 1000" (manufactured by Cosmo Oil Co., Ltd., trade name, high boiling point petroleum solvent); ethyl acetate, butyl acetate, propylpropyl ate, butyl propionate, 1-methoxy-2-propyl acetate, 2-ethoxyethyl propionate, ethyl-3-ethoxy propionate, 3-methoxybutyl acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether Ester solvents such as acetate and propylene glycol monomethyl ether acetate; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and methyl amyl ketone; alcohol solvents such as isopropanol, n-butanol, isobutanol, and 2-ethylhexanol; I can do it. These can be used alone or in combination of two or more.

Coating method The objects to be coated to which the coating composition of the present invention is applied are not particularly limited, and include, for example, outer panels of automobile bodies such as passenger cars, trucks, motorcycles, and buses; automobile parts; mobile phones; Exemplary examples include outer panels of household electrical appliances such as audio equipment, among which outer panels of automobile bodies and automobile parts are preferred.

The material of the object to be coated is not particularly limited, and examples thereof include iron, aluminum, brass, copper, tinplate, stainless steel, galvanized steel, alloyed zinc (Zn-Al, Zn-Ni, Zn-Fe, etc.) Metal materials such as plated steel; Resins such as polyethylene resin, polypropylene resin, acrylonitrile-butadiene-styrene (ABS) resin, polyamide resin, acrylic resin, vinylidene chloride resin, polycarbonate resin, polyurethane resin, epoxy resin, etc. and various types of FRP; inorganic materials such as glass, cement, and concrete; wood; and fibrous materials (paper, cloth, etc.), among which metal materials and plastic materials are preferred.

The object to be coated may be one in which the metal surface of the metal material or a car body molded from the metal material is subjected to a surface treatment such as phosphate treatment, chromate treatment, or complex oxide treatment. Furthermore, the object to be coated may be one in which an undercoat film such as various electrodeposited paints is formed on the metal base material, car body, etc., and an intermediate coat film is formed on the undercoat film. It may be something that has been done. Alternatively, a primer coating film may be formed on a plastic base material such as a bumper. Further, the intermediate coating film and the primer coating film may be uncured.

The coating method of the coating composition of the present invention is not particularly limited, and examples include coating methods such as air spray coating, airless spray coating, rotary atomization coating, and curtain coating. A wet coating film can be formed. In these coating methods, electrostatic charge may be applied if necessary. Among these, air spray coating, airless spray coating and rotary atomization coating are particularly preferred. The coating amount of the coating composition of the present invention is generally preferably such that the cured film thickness is 10 to 60 μm, particularly 25 to 50 μm.

In addition, when performing air spray painting, airless spray painting, and rotary atomization painting, the viscosity of the coating composition of the present invention is adjusted to a viscosity range suitable for the painting, usually Ford Cup No. It is preferable to adjust the viscosity as appropriate using a solvent such as an organic solvent so that the viscosity ranges from 15 to 60 seconds, particularly from 20 to 40 seconds, at 20° C. using a 4 viscometer.

Curing of a wet coating film formed by applying the coating composition of the present invention to an object to be coated can be performed by heating, and heating can be performed by a known heating means, such as a hot air oven or an electric furnace. A drying oven such as an infrared induction heating oven can be used. The heating temperature is not particularly limited, but is preferably within the range of 60 to 160°C, more preferably within the range of 80 to 140°C. The heating time is not particularly limited, but is preferably within the range of 10 to 60 minutes, more preferably within the range of 15 to 30 minutes.

The coating composition of the present invention is a coating composition that can form a coating film with excellent stain removal properties, and in particular can maintain excellent stain removal properties over a long period of time even when exposed to an outdoor environment. Since it is a coating composition that can form a coating film, it can be particularly suitably used as a top clear coat coating. The coating composition of the present invention can be particularly suitably used as a coating for automobiles.

It should be noted that although it is not necessarily clear why this paint can provide a coating film that maintains excellent contamination removal properties over a long period of time even when exposed to outdoor environments, the hydroxyl group-containing resin (A) When the hydroxyl groups in the hydroxyl group-containing acrylic resin (d2) bonded to the silica particles (D) react with the crosslinking agent (B), the hydroxyl groups in the hydroxyl group-containing resin (A) and the crosslinking agent (B) A coating film in which the silica particles (D) are firmly bonded is formed in the crosslinked coating film that is formed, and a relatively large amount of the silica particles (D) are present on the surface side of the coating film during the drying process of the coating film. The ultraviolet absorber (d31) and/or hindered amine light stabilizer (d32) present in a relatively large amount on the surface side of the coating film and bound to the silica particles (D) are transferred to the coating film. It is relatively abundant on the surface side of the film, and the ultraviolet absorption function and/or light stabilization function on the surface side of the paint film increases, and the reactive functional group-containing organopolysiloxane (C) is A relatively large amount migrates to the surface side of the coating film, and the reactive functional groups of the reactive functional group-containing organopolysiloxane (C) migrate to the surface side of the coating film, and the reactive functional groups of the reactive functional group-containing organopolysiloxane (C) are hydroxyl group-containing resin (A), The reactivity is increased by a crosslinking reaction with the crosslinking agent (B) and/or the silica particles (D) and/or a self-crosslinking reaction by the reactive functional group itself of the reactive functional group-containing organopolysiloxane (C). The functional group-containing organopolysiloxane (C) is present in a cross-linked state near the coating surface, and the ultraviolet absorber (d31) and/or hindered amine photostabilizer bonded to the silica particles (D). The agent (d32) is firmly bonded to the crosslinked coating film formed by the hydroxyl group-containing resin (A) and the crosslinking agent (B), thereby suppressing its outflow from the coating film due to rain, etc. It is assumed that the deterioration of the coating film is effectively suppressed over a long period of time.

Method for forming a multilayer coating film The method for forming a multilayer coating film in which the coating composition of the present invention is applied as a top clear coat coating includes sequentially applying at least one layer of colored coating material and at least one layer of clear coating to the object to be coated. A method for forming a multilayer coating film by applying a paint can be mentioned, which includes applying the coating composition of the present invention as the uppermost clear coat coating.

Specifically, for example, after forming an undercoat film with an electrodeposition paint and curing the undercoat film, an intermediate coat film is formed on the undercoat film with an intermediate coat paint, and the intermediate coat film is cured. After the film is cured, a colored paint is applied on the intermediate coat film, and if necessary, 40% After preheating at ~90°C for about 3 to 30 minutes and applying the coating composition of the present invention as a clear coat paint onto this uncured colored paint film, the colored paint film and clear coat paint film are combined. A two-coat, one-bake method in which the two coats are cured together; an undercoat film is formed with an electrodeposition paint, and after the undercoat film is cured, an intermediate coat film is formed on the undercoat film with an intermediate paint; In order to accelerate the volatilization of the solvent in the intermediate coating as necessary without curing the intermediate coating, for example, preheating is performed at 40 to 90°C for about 3 to 30 minutes, and this uncured A colored paint is applied onto the intermediate coating film, and the coating is heated, for example, at 40 to 90°C for 3 to 30 minutes in order to accelerate the volatilization of the solvent in the colored paint as necessary without curing the paint film. After applying the coating composition of the present invention as a clear coat paint onto this uncured colored paint film, the intermediate coat film, colored paint film, and clear coat paint film are cured together. A three-coat, one-bake method for forming a multilayer coating film can be mentioned.

As the intermediate coating used above, conventionally known thermosetting intermediate coatings can be used, and specifically, for example, acrylic resin, polyester resin, alkyd resin, urethane resin, etc. A coating material can be used in which a crosslinking agent such as an amino resin, a polyisocyanate compound, or a blocked polyisocyanate compound is appropriately combined with a reactive functional group contained in the base resin. The reactive functional group contained in the base resin is preferably a hydroxyl group.

Further, as the intermediate coating paint, for example, a water-based paint, an organic solvent-based paint, or a powder paint can be used. Among these, water-based paints are preferred from the viewpoint of reducing environmental impact and improving the finished appearance of the paint film.

Furthermore, as the coloring paint used above, conventionally known normal thermosetting coloring paints can be used, and specifically, for example, base materials such as acrylic resin, polyester resin, alkyd resin, urethane resin, etc. It is possible to use a coating material in which a resin is appropriately combined with a crosslinking agent such as an amino resin, a polyisocyanate compound, a blocked polyisocyanate compound, and a reactive functional group contained in the base resin. The reactive functional group contained in the base resin is preferably a hydroxyl group.

Further, as the colored paint, for example, a water-based paint, an organic solvent-based paint, or a powder paint can be used. Among these, water-based paints are preferred from the viewpoint of reducing environmental impact and improving the finished appearance of the paint film.

In the above method for forming a multilayer coating film, when two or more layers of clear coat are applied, the coating composition of the present invention may be used as the clear coat coating other than the uppermost layer, and the coating composition of the present invention may be used as a clear coat coating of the present invention. Coating paint may also be used.

Hereinafter, the present invention will be explained in more detail with reference to Production Examples, Examples, and Comparative Examples. However, the present invention is not limited to these. In each example, "parts" and "%" are based on mass unless otherwise specified. Further, the film thickness of the coating film is based on the cured coating film.

Production example 1 of hydroxyl group-containing resin (A)
In a reaction vessel equipped with a thermometer, thermostat, stirring device, reflux condenser, nitrogen inlet tube, and dropping device, 27 parts of “Swazol 1000” (trade name, manufactured by Cosmo Oil Co., Ltd., aromatic organic solvent) and propylene glycol monomethyl were added. Charge 5 parts of ether acetate and stir at 150°C while blowing nitrogen gas, and add 22 parts of styrene, 18 parts of 2-hydroxypropyl acrylate, 4 parts of 4-hydroxybutyl acrylate, 55 parts of isobutyl methacrylate, and 1.5 parts of acrylic acid. A monomer mixture consisting of 0 parts and 1.5 parts of ditertiaryamyl peroxide (polymerization initiator) was added dropwise at a uniform rate over 4 hours. Thereafter, the mixture was aged at 150° C. for 1 hour, cooled, and further diluted by adding 34 parts of butyl acetate to obtain a secondary hydroxyl group-containing acrylic resin (A1'-1) solution with a solid content concentration of 60% by mass. The obtained secondary hydroxyl group-containing acrylic resin (A1'-1) had a hydroxyl value of 93 mgKOH/g, an acid value of 6.7 mgKOH/g, a weight average molecular weight of 8,000, and a glass transition temperature of 44.3°C. Ta.

Manufacturing example 2
In a reaction vessel equipped with a thermometer, thermostat, stirring device, reflux condenser, nitrogen inlet tube, and dropping device, 27 parts of “Swazol 1000” (trade name, manufactured by Cosmo Oil Co., Ltd., aromatic organic solvent) and propylene glycol monomethyl were added. Charge 5 parts of ether acetate, stir at 150°C while blowing nitrogen gas, and add 17 parts of styrene, 28.5 parts of 2-hydroxypropyl acrylate, 10.5 parts of 4-hydroxybutyl acrylate, 43 parts of isobutyl methacrylate, A monomer mixture consisting of 1.0 parts of acrylic acid and 1.5 parts of ditertiary amyl peroxide (polymerization initiator) was added dropwise at a uniform rate over 4 hours. Thereafter, the mixture was aged at 150° C. for 1 hour, cooled, and further diluted by adding 34 parts of butyl acetate to obtain a secondary hydroxyl group-containing acrylic resin (A1'-2) solution with a solid content concentration of 60% by mass. The obtained secondary hydroxyl group-containing acrylic resin (A1'-2) had a hydroxyl value of 164 mgKOH/g, an acid value of 6.7 mgKOH/g, a weight average molecular weight of 8,000, and a glass transition temperature of 27.9°C. Ta.

Manufacturing example 3
In a reaction vessel equipped with a thermometer, thermostat, stirring device, reflux condenser, nitrogen introduction pipe, and dropping device, 30 parts of "Swazol 1000" (trade name, manufactured by Cosmo Oil Co., Ltd., aromatic organic solvent) and n-butanol were added. I prepared 10 copies. The charge solution was stirred at 125°C while blowing nitrogen gas into the reaction vessel, and 15 parts of γ-methacryloxypropyltrimethoxysilane, 22 parts of styrene, 18 parts of 2-hydroxypropyl acrylate, and 4 parts of 4-hydroxybutyl acrylate were added to the solution. A monomer mixture consisting of 41 parts of isobutyl methacrylate and 4.5 parts of 2,2'-azobis(2-methylbutyronitrile) (polymerization initiator) was added dropwise at a uniform rate over 4 hours. Then, after aging at 125°C for 30 minutes, 0.5 part of 2,2'-azobis(2-methylbutyronitrile) and "Swazol 1000" (trade name, manufactured by Cosmo Oil Co., Ltd., aromatic organic solvent) A solution consisting of 5.0 parts was added dropwise at a uniform rate over 1 hour. Thereafter, it was aged at 125°C for 1 hour and then cooled, further diluted with 8 parts of isobutyl acetate, and an acrylic resin (A1'''-1 ) solution was obtained. The alkoxysilyl group content of the obtained acrylic resin (A1'''-1) having secondary hydroxyl groups and alkoxysilyl groups was 0.6 mmol/g, the hydroxyl value was 93 mgKOH/g, and the weight average molecular weight was 8,000. The glass transition temperature was 33.2°C.

Production example 4
In a reaction vessel equipped with a thermometer, thermostat, stirring device, reflux condenser, nitrogen introduction pipe, and dropping device, 30 parts of "Swazol 1000" (trade name, manufactured by Cosmo Oil Co., Ltd., aromatic organic solvent) and n-butanol were added. I prepared 10 copies. The charge solution was stirred at 125° C. while blowing nitrogen gas into the reaction vessel, and 15 parts of γ-methacryloxypropyltrimethoxysilane, 10 parts of styrene, 28.5 parts of 2-hydroxypropyl acrylate, and 4-hydroxybutyl acrylate were added. A monomer mixture consisting of 10.5 parts of isobutyl methacrylate, 36 parts of isobutyl methacrylate, and 4.5 parts of 2,2'-azobis(2-methylbutyronitrile) (polymerization initiator) was added dropwise at a uniform rate over 4 hours. Then, after aging at 125°C for 30 minutes, 0.5 part of 2,2'-azobis(2-methylbutyronitrile) and "Swazol 1000" (trade name, manufactured by Cosmo Oil Co., Ltd., aromatic organic solvent) A solution consisting of 5.0 parts was added dropwise at a uniform rate over 1 hour. Thereafter, the mixture was aged at 125°C for 1 hour, cooled, and further diluted with 8 parts of isobutyl acetate. ) solution was obtained. The alkoxysilyl group content of the obtained acrylic resin (A1'''-2) having secondary hydroxyl groups and alkoxysilyl groups was 0.6 mmol/g, the hydroxyl value was 164 mgKOH/g, and the weight average molecular weight was 8,000. The glass transition temperature was 15.6°C.

Production of a compound having an ultraviolet absorbing group and a hydrolyzable silyl group Production Example 5
"SILIQUEST A-Link 25 Silane" (trade name, manufactured by Momentive Performance Materials, 3-isocyanatepropyltriethoxysilane, solid content 100 %), 137.7 parts of "Tinuvin 405" (trade name, manufactured by BASF, ultraviolet absorber having a hydroxyl group, solid content 100%) and 207.7 parts of butyl acetate, and the mixture was mixed and stirred at room temperature. Thereafter, a reaction was carried out at 80° C. for 3 hours using a mantle heater to obtain a compound (s-1) having an ultraviolet absorbing group and a hydrolyzable silyl group and having a solid content concentration of 50% by mass.

Manufacturing example 6
"SILIQUEST A-Link 35 Silane" (trade name, manufactured by Momentive Performance Materials, 3-isocyanatepropyltrimethoxysilane, solid content 100 %), 165.9 parts of "Tinuvin 405" (trade name, manufactured by BASF, ultraviolet absorber having a hydroxyl group, solid content 100%) and 235.9 parts of butyl acetate, and the mixture was mixed and stirred at room temperature. Thereafter, a reaction was carried out at 80° C. for 3 hours using a mantle heater to obtain a compound (s-2) having an ultraviolet absorbing group and a hydrolyzable silyl group and having a solid content concentration of 50% by mass.

Production of a compound having a hindered amine photostabilizing group and a hydrolyzable silyl group Production Example 7
"SILIQUEST A-Link 25 Silane" (trade name, manufactured by Momentive Performance Materials, 3-isocyanatepropyltriethoxysilane, solid content 100 %), 203.4 parts of "Tinuvin 152" (trade name, manufactured by BASF, hindered amine light stabilizer with hydroxyl group, solid content 100%) and 273.4 g of butyl acetate, and the mixture was mixed and stirred at room temperature. Thereafter, a reaction was carried out at 80° C. for 3 hours using a mantle heater to obtain a compound (s-3) having a hindered amine photostabilizing group and a hydrolyzable silyl group and having a solid content concentration of 50% by mass.

Production example 8
"SILIQUEST A-Link 35 Silane" (trade name, manufactured by Momentive Performance Materials, 3-isocyanatepropyltrimethoxysilane, solid content 100 %), 245.1 parts of "Tinuvin 152" (trade name, manufactured by BASF, hindered amine light stabilizer having a hydroxyl group, solid content 100%), and 315.1 g of butyl acetate, and the mixture was mixed and stirred at room temperature. Thereafter, a reaction was carried out at 80° C. for 3 hours using a mantle heater to obtain a compound (s-4) having a hindered amine photostabilizing group and a hydrolyzable silyl group and having a solid content concentration of 50% by mass.

Production of silica particles (d1) having polymerizable unsaturated groups Production Example 9
In a separable flask equipped with a reflux condenser, a thermometer, and a stirrer, "PGM-ST" (trade name, manufactured by Nissan Chemical Industries, Ltd., silica average primary particle diameter: 15 nm, silica concentration: 30% by mass, dispersion medium: propylene) was added. After adding 333 parts of glycol monomethyl ether (solid content 100 parts) and 10 parts of deionized water, 10 parts of "KBM-503" (trade name, manufactured by Shin-Etsu Chemical Co., Ltd., γ-methacryloyloxypropyltrimethoxysilane) ( A dehydration condensation reaction was carried out with stirring at 80° C. for 3 hours, and then 0.03 part of tetra-n-butylammonium fluoride was added and the reaction was further carried out with stirring for 1 hour. After the reaction was completed, 30 parts of propylene glycol monomethyl ether was added, and then volatile components were distilled off under reduced pressure to obtain a silica particle dispersion (d1-1) having a polymerizable unsaturated group with a solid content of 40%. .

Production example 10
In a separable flask equipped with a reflux condenser, a thermometer, and a stirrer, "Snowtex O-40" (trade name, manufactured by Nissan Chemical Industries, Ltd., silica average primary particle diameter: 20 to 25 nm, silica concentration: 40% by mass, After adding 250 parts of dispersion medium (water) (solid content 100 parts) and 250 parts of propylene glycol monomethyl ether, "KBM-503" (trade name, manufactured by Shin-Etsu Chemical Co., Ltd., γ-methacryloyloxypropyltrimethoxysilane) 10 (solid content: 10 parts), and a dehydration condensation reaction was carried out with stirring at 80°C for 3 hours. Thereafter, 0.03 part of tetra-n-butylammonium fluoride was added and the reaction was further carried out with stirring for 1 hour. Ta. After the reaction was completed, 200 parts of propylene glycol monomethyl ether was added, and then volatile components were distilled off under reduced pressure to obtain a silica particle dispersion (d1-2) having a polymerizable unsaturated group with a solid content of 40%. .

Production of silica particles (d1') to which an ultraviolet absorber (d31) and/or a hindered amine light stabilizer (d32) is bonded and which has a polymerizable unsaturated group Production Example 11
In a separable flask equipped with a reflux condenser, a thermometer, and a stirrer, "PGM-ST" (trade name, manufactured by Nissan Chemical Industries, Ltd., silica average primary particle diameter: 15 nm, silica concentration: 30% by mass, dispersion medium: propylene) was added. After adding 333 parts of glycol monomethyl ether (solid content 100 parts) and 10 parts of deionized water, 10 parts of "KBM-503" (trade name, manufactured by Shin-Etsu Chemical Co., Ltd., γ-methacryloyloxypropyltrimethoxysilane) ( 10 parts of solid content) and 20 parts of the compound (s-1) having an ultraviolet absorbing group and a hydrolyzable silyl group obtained in Production Example 5 (10 parts of solid content) were added, and the mixture was stirred at 80°C for 3 hours. After that, 0.03 part of tetra-n-butylammonium fluoride was added and the reaction was further continued for 1 hour with stirring. After the reaction is completed, 30 parts of propylene glycol monomethyl ether is added, and then volatile components are distilled off under reduced pressure to obtain a product with a solid content of 40%, to which the ultraviolet absorber (d31) is bound and which has a polymerizable unsaturated group. A silica particle dispersion (d1'-1) was obtained.

Production examples 12 to 15
In the same manner as in Production Example 11 except for the formulation shown in Table 1, a UV absorber (d31) and/or a hindered amine light stabilizer (d32) with a solid content of 40% was combined and a polymerizable non-polymerizable Silica particle dispersions (d1'-2) to (d1'-5) having saturated groups were obtained.

(Note 1) "TMPS-E": Trade name, manufactured by Shin-Etsu Chemical Co., Ltd., compound having a hindered amine photostabilizing group and a hydrolyzable silyl group, active ingredient 95% or more.

Production example 16
In a separable flask equipped with a reflux condenser, a thermometer, and a stirrer, "Snowtex O-40" (trade name, manufactured by Nissan Chemical Industries, Ltd., silica average primary particle diameter: 20 to 25 nm, silica concentration: 40% by mass, After adding 250 parts of dispersion medium (water) (solid content 100 parts) and 250 parts of propylene glycol monomethyl ether, "KBM-503" (trade name, manufactured by Shin-Etsu Chemical Co., Ltd., γ-methacryloyloxypropyltrimethoxysilane) 10 (solid content 10 parts), 20 parts (solid content 10 parts) of the compound (s-1) having an ultraviolet absorbing group and a hydrolyzable silyl group obtained in Production Example 5, and the hindered amine type obtained in Production Example 7 20 parts (solid content: 10 parts) of compound (s-3) having a photostabilizing group and a hydrolyzable silyl group were added, and a dehydration condensation reaction was carried out with stirring at 80°C for 3 hours. 0.03 part of -n-butylammonium was added, and the mixture was further reacted with stirring for 1 hour. After the reaction was completed, 200 parts of propylene glycol monomethyl ether was added, and volatile components were distilled off under reduced pressure to obtain an ultraviolet absorber (d31) and hindered amine light stabilizer (d32) with a solid content of 40%. A dispersion of silica particles (d1'-6) having bonded and polymerizable unsaturated groups was obtained.

Production of silica particle (D) dispersion bound to hydroxyl group-containing acrylic resin (d2) and bound to ultraviolet absorber (d31) and/or hindered amine light stabilizer (d32) Production Example 17
A separable flask equipped with a reflux condenser, a thermometer, a stirrer, and a nitrogen gas inlet was charged with 135 parts of propylene glycol monomethyl ether, and the temperature was raised to 100° C. under nitrogen gas ventilation. After reaching 100°C, 275 parts (solid content 110 parts) of the dispersion of silica particles having polymerizable unsaturated groups (d1-1) obtained in Production Example 9, 30 parts of 2-hydroxyethyl methacrylate, and "RUVA- 93'' (trade name, manufactured by Otsuka Chemical Co., Ltd., polymerizable unsaturated monomer bonded with ultraviolet absorber (d31)) 5 parts (solid content 5 parts), 21.5 parts of styrene, 8.5 parts of 2-ethylhexyl acrylate, "X-22-174ASX" (trade name, manufactured by Shin-Etsu Chemical Co., Ltd., polysiloxane chain-containing polymerizable unsaturated monomer) 5 parts (solid content 5 parts), "KBM-503" (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) , γ-methacryloyloxypropyltrimethoxysilane) 30 parts (solid content 30 parts), "V-59" (trade name, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 2,2'-azobis(2-methylbutyronitrile)) 2.5 parts of the mixture (solid content: 2.5 parts) was added dropwise over 2 hours. Next, after aging at 100°C for 1 hour, a mixed solution of 0.83 parts of "V-59" and 20 parts of propylene glycol monomethyl ether was added dropwise over 0.5 hours, and the mixture was further aged for 2 hours. The polymerization rate determined from nonvolatile components was 99%. Thereafter, ethoxyethyl propionate was added and the solvent was replaced by azeotropic distillation under reduced pressure to obtain a silica particle dispersion (D-1) with a measured nonvolatile content of 40%.
Production examples 18-47
Silica particle dispersions (D-2) to (D-31) were obtained in the same manner as Production Example 17 except that the formulations shown in Table 2 were used. Among these, in the silica particle dispersion (D-30), the ultraviolet absorber (d31) and the hindered amine light stabilizer (d32) are not bonded, so the hydroxyl group-containing acrylic resin (d2) is bonded, And it does not correspond to a silica particle (D) dispersion to which an ultraviolet absorber (d31) and/or a hindered amine light stabilizer (d32) is bonded. Further, since the silica particle dispersion (D-31) does not have the hydroxyl group-containing acrylic resin (d2) bonded thereto, this also does not fall under the above-mentioned silica particle (D) dispersion.

(Note 2) "ADEKA STAB LA-82": Product name, manufactured by ADEKA Co., Ltd., a polymerizable unsaturated monomer bound to a hindered amine light stabilizer (c22),
(Note 3) "ADEKA STAB LA-87": Product name, manufactured by ADEKA Co., Ltd., a polymerizable unsaturated monomer bound to a hindered amine light stabilizer (c22).

Production example 1 of coating composition
120 parts (solid content 72 parts) of the acrylic resin (A1'''-1) solution having secondary hydroxyl groups and alkoxysilyl groups obtained in Production Example 3, "Sumidur N3300" (trade name, manufactured by Sumitomo Covestro Urethane Co., Ltd.) , isocyanurate cycloadduct of hexamethylene diisocyanate, solid content 100%) 28 parts (solid content 28 parts), "Silmer TMS Di10" (trade name, manufactured by SILTECH, amino group-containing organopolysiloxane, solid content 100) %) 0.2 parts (solid content 0.2 parts), 25 parts (solid content 10 parts) of the silica particle dispersion (D-1) obtained in Production Example 17, "NACURE 4167" (trade name, KING INDUSTRIES) "Tinuvin 400" (trade name, manufactured by BASF, benzotriazole ultraviolet absorber, solid content 100%) 1. 5 parts (solid content 1.5 parts), "Tinuvin123" (trade name, manufactured by BASF, hindered amine light stabilizer without hydroxyl group, solid content 100%) 1.5 parts (solid content 1.5 parts) and "BYK-300" (trade name, manufactured by BYK Chemie Co., Ltd., surface conditioner, active ingredient 52%) 0.38 parts (solid content 0.2 parts) were mixed uniformly, and further, butyl acetate was added, and 20 Ford Cup No. Paint composition No. 4 was adjusted so that the viscosity was 30 seconds. I got 1.

Examples 2 to 45, Comparative Examples 1 to 3
In Example 1, coating composition No. 1 was prepared in the same manner as in Example 1 except that the formulation of each component was changed to the formulation shown in Table 3 below. 2~No. I got 48.

Evaluation of paint composition (preparation of painted plates for testing)
A cold-rolled steel sheet that had been subjected to zinc phosphate chemical conversion treatment was electrodeposited with "Electron GT-10" (trade name, manufactured by Kansai Paint Co., Ltd., cationic electrodeposition paint) to a dry film thickness of 20 μm, and then heated at 170°C. Heating was performed for 30 minutes to form a cured electrodeposited coating. “WP-522H” (trade name, manufactured by Kansai Paint Co., Ltd., polyester resin/amino resin water-based intermediate coating paint) was applied onto the electrodeposited film using a rotary atomization type electrostatic coating machine to form a cured film. Electrostatic coating was applied to a thickness of 30 μm, and after standing for 5 minutes, preheating was performed at 80° C. for 3 minutes to form an uncured intermediate coating film. "WBC-713T" (trade name, manufactured by Kansai Paint Co., Ltd., acrylic melamine resin water-based base coat paint, white paint color) was applied onto the uncured intermediate coat using a rotary atomizing electrostatic coating machine. Then, electrostatic coating was applied so that the cured film thickness was 15 μm, and after being left for 5 minutes, preheating was performed at 80° C. for 3 minutes to form an uncured base coat film.

Next, coating composition No. 1 obtained in Example 1 was applied onto the uncured base coat film. 1 was electrostatically coated using a rotary atomizing type electrostatic coating machine to form a clear coat film to a dry film thickness of 40 μm, and the film was left for 7 minutes. Next, the test coated board of Example 1 was prepared by heating at 140° C. for 30 minutes to heat and cure the uncured intermediate coat film, the uncured base coat film, and the uncured clear coat film. .

Manufacture of test coated plates of Examples 2 to 45 and Comparative Examples 1 to 3 The above coating composition No. In the preparation of test coated board No. 1, coating composition No. 1 was prepared. 1 and paint composition No. 1, respectively. Coating composition No. 2 to 48 was used. Coated test panels of Examples 2 to 45 and Comparative Examples 1 to 3 were produced in the same manner as the test coated panels of Example 1.

Each coated test plate obtained above was evaluated by the following test method. The evaluation results are shown in Table 3 together with the paint composition.

(Test method)
Contamination Removal Properties A 20 mm x 20 mm square was drawn using an oil-based marker "Magic Ink Extra Thick MGD-T1 Black" (trade name, manufactured by Teranishi Kogyo Co., Ltd., black oil-based marker) on each of the test painted plates obtained above to smear the stains. . After that, let it stand for 1 minute, observe the condition, then wipe off the contaminated area using dry "Cellleaf WA-25C" (trade name, manufactured by Ozu Sangyo Co., Ltd., non-woven fabric wiper), and observe the above area. , was evaluated using the following criteria. A and B are passing levels.
A: The ink is repelled and there is no color residue after wiping it off.
B: Ink is repelled over 40% or more of the contaminated area, and there is almost no color remaining after wiping.
C: Ink is repelled in less than 40% of the contaminated area, and color remains even after wiping.
D: Ink is not repelled and color remains even after wiping.

Contamination Removal Properties After Outdoor Exposure Each test coated plate obtained above was mounted facing south at an angle of 4 degrees from the vertical on Okinoerabu Island, Kagoshima Prefecture, and exposed outdoors for 12 months. Thereafter, a 20 mm x 20 mm square was drawn with an oil marker "Magic Ink Extra Thick MGD-T1 Black" (trade name, manufactured by Teranishi Kogyo Co., Ltd., black oil marker) on each test coated plate after outdoor exposure to contaminate it. After that, let it stand for 1 minute, observe the condition, then wipe off the contaminated area using dry "Cellleaf WA-25C" (trade name, manufactured by Ozu Sangyo Co., Ltd., non-woven fabric wiper), and observe the above area. , was evaluated using the following criteria. A and B are passing levels.
A: The ink is repelled and there is no color residue after wiping it off.
B: Ink is repelled over 40% or more of the contaminated area, and there is almost no color remaining after wiping.
C: Ink is repelled in less than 40% of the contaminated area, and color remains even after wiping.
D: Ink is not repelled and color remains even after wiping.

(Note 4) “Cymel 202”: Product name, manufactured by Allnex Japan Co., Ltd., melamine resin, solid content 80%,
(Note 5) "XR31-B1410": Product name, manufactured by Momentive Performance Materials Japan LLC, alkoxysilyl group-containing organopolysiloxane, solid content 100%,
(Note 6) "KR-500": Product name, manufactured by Shin-Etsu Chemical Co., Ltd., organopolysiloxane containing alkoxysilyl groups, solid content 100%,
(Note 7) "KR-510": Product name, manufactured by Shin-Etsu Chemical Co., Ltd., organopolysiloxane containing alkoxysilyl groups, solid content 100%,
(Note 8) "KF-8010": Product name, manufactured by Shin-Etsu Chemical Co., Ltd., amino group-containing organopolysiloxane, solid content 100%,
(Note 9) "Silmer NH Di8": Product name, manufactured by SILTECH, amino group-containing organopolysiloxane, solid content 100%,
(Note 10) "BYK-333": Trade name, manufactured by BYK Chemie, surface conditioner, 100% active ingredient.

Although the embodiments and examples of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and various modifications can be made based on the technical idea of the present invention.

Claims (16)

hydroxyl group-containing resin (A),
crosslinking agent (B),
a reactive functional group-containing organopolysiloxane (C), and
A coating composition containing a silica particle (D) dispersion bound to a hydroxyl group-containing acrylic resin (d2) and bound to an ultraviolet absorber (d31) and/or a hindered amine light stabilizer (d32). The coating composition according to claim 1, wherein the hydroxyl group-containing resin (A) includes a resin (A') having a hydroxyl group and an alkoxysilyl group. The coating composition according to claim 1 or 2, wherein the hydroxyl group-containing resin (A) contains a hydroxyl group-containing acrylic resin (A1). The coating composition according to any one of claims 1 to 3, wherein the crosslinking agent (B) contains a polyisocyanate compound (B1). The ultraviolet absorber (d31) and/or the hindered amine light stabilizer (d32) are bonded to the hydroxyl group-containing acrylic resin (d2), and the ultraviolet absorber (d31) and/or the hindered amine light stabilizer (d32) The coating composition according to any one of claims 1 to 4, wherein the hydroxyl group-containing acrylic resin (d2) to which the light stabilizer (d32) is bound is bound to the silica particles (D). The silica particle (D) dispersion contains a reaction product of the silica particle (d1) having a polymerizable unsaturated group and the polymerizable unsaturated monomer mixture (d2-1), and d2-1) is bonded with a hydroxyl group-containing polymerizable unsaturated monomer, a polymerizable unsaturated monomer bonded with an ultraviolet absorber (d31), and a hindered amine light stabilizer (d32) as at least a part of its components. The coating composition according to claim 5, comprising at least one polymerizable unsaturated monomer selected from the above polymerizable unsaturated monomers. The polymerizable unsaturated monomer to which the ultraviolet absorber (d31) is bonded and the polymerizable unsaturated monomer to which the hindered amine light stabilizer (d32) is bonded in the polymerizable unsaturated monomer mixture (d2-1). The coating composition according to claim 6, wherein the total proportion is within the range of 0.5 to 40% by mass based on the total amount of the polymerizable unsaturated monomer mixture (d2-1). The coating composition according to claim 6 or 7, wherein the polymerizable unsaturated monomer mixture (d2-1) further contains an alkoxysilyl group-containing polymerizable unsaturated monomer. (Effect: Contamination removal)
The coating composition according to any one of claims 6 to 8, wherein the polymerizable unsaturated monomer mixture (d2-1) further contains a polysiloxane chain-containing polymerizable unsaturated monomer. The mass ratio of the silica particles having a polymerizable unsaturated group (d1) and the polymerizable unsaturated monomer mixture (d2-1) is 20/80 to 90/ in the ratio of (d1)/(d2-1). The coating composition according to any one of claims 6 to 9, which is within the range of 10. Claims 1 to 3, wherein the ultraviolet absorber (d31) and/or the hindered amine light stabilizer (d32) are bonded to the silica particles (D) independently of the hydroxyl group-containing acrylic resin (d2). 10. The coating composition according to any one of 10. The silica particle (D) dispersion is polymerized with silica particles (d1') to which an ultraviolet absorber (d31) and/or a hindered amine light stabilizer (d32) is bonded and which has a polymerizable unsaturated group. and the polymerizable unsaturated monomer mixture (d2-1') contains a hydroxyl group-containing polymerizable unsaturated monomer as at least a part of its components. and the polymerizable unsaturated monomer mixture (d2-1') is a polymerizable unsaturated monomer to which a UV absorber (d31) is bonded and a hindered amine light stabilizer (d32). 12. The coating composition according to claim 11, which is monomer-free. The coating composition according to claim 12, wherein the polymerizable unsaturated monomer mixture (d2-1') further contains an alkoxysilyl group-containing polymerizable unsaturated monomer. The coating composition according to claim 12 or 13, wherein the polymerizable unsaturated monomer mixture (d2-1') further contains a polysiloxane chain-containing polymerizable unsaturated monomer. Silica particles (d1') to which the ultraviolet absorber (d31) and/or hindered amine light stabilizer (d32) are bonded and have a polymerizable unsaturated group, and the polymerizable unsaturated monomer mixture (d2- The paint according to any one of claims 12 to 14, wherein the mass ratio with 1') is within the range of 20/80 to 90/10 as a ratio of (d1')/(d2-1'). Composition. A method for forming a multi-layer coating film by sequentially coating an object with at least one layer of colored paint and at least one layer of clear coat paint, wherein the clear coat paint is the uppermost layer. A method for forming a multilayer coating film, the method comprising coating the coating composition according to any one of the above.