JP2001226634A - Coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating composition that is characterized in including a polysilsesquioxane having excellent adhesion to the substrate and also high weather resistance, heat resistance, and high hardness. SOLUTION: The objective coating composition is characterized in comprising (A) a polyalkylsilsesquioxane that has an alkoxy group of which >=30 mol.% is trialkylsilylated or hydroxyl on the chain terminals and has an organic group bearing an ethylenically double bond and an alkyl group on the side chains, (B) a poly(meth)acrylate and (C) a phosphoric ester of hydroxyalkyl (meth) acrylate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a resin composition used as a coating material for various substrates. Further, the present invention relates to a silicone resin composition used for the purpose of modifying the surface of various substrates, and more particularly to a silicone-based coating composition having excellent heat resistance and adhesion.

[0002]

2. Description of the Related Art Weather resistance is achieved by a coating method (coating).
Silicone resins and the like are used as materials for imparting heat resistance, water repellency and the like to various substrate surfaces. Silicone compounds and silicone resins have been attracting attention as environmentally friendly materials in recent years. Among them, polyalkylsilsesquioxane having a ladder structure is being spotlighted from the viewpoint of heat resistance and high hardness. .

For this purpose, a macromer having a double bond added to polyalkylsilsesquioxane (Japanese Patent Laid-Open No. 61-8 / 1986)
No. 0755) and a composition of a poly (meth) acrylate and a photopolymerization initiator (JP-A-3-281616).
Publication). The polyalkylsilsesquioxane having these double bonds has a problem in heat or storage stability because the terminal is an alkoxy group or a hydroxyl group. In particular, when most of the side chains of the polyalkylsilsesquioxane structure having a terminal alkoxy group or hydroxyl group are methyl groups, the stability is particularly poor, and gelation is likely to occur. To solve this problem, it has been proposed to trimethylsilylate a part or most of the terminal alkoxy group or hydroxyl group (JP-A-7-70321).

[0004] However, polyalkylsilsesquioxanes whose terminals are trimethylsilylated have poor adhesion to substrates, and in particular, have extremely poor adhesion to metals.

[0005]

An object of the present invention is to provide a coating comprising a polysilsesquioxane compound having high weather resistance, high heat resistance, high hardness and excellent adhesion to a substrate (substrate). It is to provide a composition.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to solve the above-mentioned problem of adhesion to a substrate, and as a result, have found that at least 30 mol% of trimethoxysilylated alkoxy or hydroxyl groups are terminated. Phosphoric acid of polyalkylsilsesquioxane (A), poly (meth) acrylate (B), and hydroxyalkyl (meth) acrylate having an organic group having an ethylenic double bond and an alkyl group in the side chain The present invention has been completed by obtaining an adhesive coating composition comprising the ester (C).

That is, the present invention relates to the following matters. [1] 30 mol% or more is trialkylsilylated,
The remainder has a terminal group that is an alkoxy group or a hydroxyl group,
Polyalkylsilsesquioxane (A) having an organic group having an ethylenic double bond and an alkyl group in a side chain (A), poly (meth) acrylate (B), and phosphate of hydroxyalkyl (meth) acrylate (C) A) a coating composition comprising:

[2] The composition according to claim 1, which contains a polymerization initiator (D).
A coating composition according to claim 1. [3] The coating composition according to [1] or [2], wherein 70 mol% or more of the alkyl groups of the polyalkylsilsesquioxane (A) are methyl groups. [4] The coating composition according to any of [1] to [3], wherein the hydroxyalkyl (meth) acrylate phosphate (C) is mono (meth) acryloxyethyl phosphate or di (meth) acryloxyethyl phosphate. .

[5] The polyalkylsilsesquioxane (A) is a repeating unit represented by the following general formula (1) and a terminal group represented by the following general formula (2):

Embedded image (Wherein, R ¹ and R ² each independently represent an alkyl group having 1 to 8 carbon atoms or an organic group having an ethylenic double bond, provided that 70 mol% or more represents a methyl group.) )

Embedded image (Wherein, R ¹ and R ² have the same meanings as above. R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or a trimethylsilyl group, provided that 30 mol%
The above represents a trimethylsilyl group. The adhesive coating composition according to [3] or [4], which is a compound represented by the following formula:

[6] The mixing ratio of polyalkylsilsesquioxane (A), poly (meth) acrylate (B) and phosphate of hydroxyalkyl (meth) acrylate (C) is 100: 1 by mass ratio. ~ 100: 1 ~
10. The coating composition according to [1] to [5], which is 10. [7] A paint containing the coating composition according to [1] to [6]. [8] A method for improving the surface of a substrate, comprising coating the substrate with the coating composition according to [1] to [6].

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The term (meth) acryl used herein means "acryl" and / or "methacryl".

In the polyalkylsilsesquioxane (A) used in the present invention, at least 30 mol% of the terminal groups are trimethylsilylated, and the remainder is an alkoxy group or a hydroxyl group, and an organic group having an ethylenic double bond; It has an alkyl group on the side chain.

Preferably, a repeating unit represented by the following general formula (1) and a terminal group represented by the following general formula (2):

Embedded image (In the formula, R ¹ and R ² each independently represent an alkyl group having 1 to 8 carbon atoms or an organic group having an ethylenic double bond, provided that 70 mol% or more represents a methyl group.) )

Embedded image (Wherein, R ¹ and R ² have the same meanings as above. R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or a trimethylsilyl group, provided that 30 mol%
The above represents a trimethylsilyl group. ).

The polyalkylsilsesquioxane (A) of the present invention can be obtained, for example, by trialkylsilylating a polyalkylsilsesquioxane compound having a terminal alkoxy group or a hydroxyl group. As the method, a conventionally known method may be used. For example, a method of reacting a trialkylsilanol with a polyalkylsilsesquioxane compound, a method of reacting a hexaalkyldisiloxane in a weakly acidic atmosphere, and the like can be used.

In the polyalkylsilsesquioxane (A) of the present invention, it is necessary that at least 30 mol% of the terminal hydroxyl groups or alkoxy groups be trialkylsilylated, and if it is less than 30%, it is storage-stable. Sex becomes poor. It is preferably at least 50%, and more preferably at least 99%.

The method for producing a polyalkylsilsesquioxane compound before trialkylsilylation is carried out by co-hydrolyzing a trialkoxysilane compound having a group having an ethylenic double bond and a trialkoxysilane compound having an alkyl group. Obtained by condensation. Instead of the trialkoxysilane compound having an alkyl group, co-hydrolytic condensation of a corresponding trichlorosilane compound may be used.

The poly (meth) acrylate (B) in the present invention is a (meth) acrylate of an organic polyhydric alcohol.

The organic polyhydric alcohol used in the present invention includes ethylene glycol, diethylene glycol,
2,2,4-trimethyl-1,3-pentanediol,
Dipropylene glycol, propylene glycol, polyethylene glycol having an average molecular weight of about 150 to about 600,
2,2-bis [4- (2-hydroxypropoxy) phenyl] propane, 2,3-butanediol, tetraethylene glycol, 2,2-bis (4-hydroxyphenyl) propane, glycerin, trimethylolpropane,
Polycaprolactone ester of trimethylolpropane including 1,4-butanediol and caprolactone, 2-
Ethyl-1,3-hexanediol, 1,5-pentanediol, tripropylene glycol, pentaerythritol, dipentaerythritol, 2,2-bis (4-
(Hydroxycyclohexyl) propane, 1,2,6-hexanetriol, 1,3-propanediol, 1,6
-Hexanediol and the like, and one or more of these can be used.

The amount (B) of the poly (meth) acrylate used in the present invention depends on the type of the polyalkylsilsesquioxane (A) and the poly (meth) acrylate (B) used. The amount is preferably 1 to 100 parts by mass with respect to 100 parts by mass of the silsesquioxane (A). If the amount is less than 1 part by mass, sufficient cross-linking cannot be obtained in the coating film, and the surface hardness becomes low. Also 100
When the amount is more than the mass part, the heat resistance deteriorates.

The hydroxyalkyl (meth) acrylate phosphate (C) of the present invention is an ester of hydroxyalkyl (meth) acrylate and phosphoric acid,
For example, (meth) acryloxyethyl phosphate, di (meth) acryloxyethyl phosphate, tri (meth) acryloxyethyl phosphate, (meth) acryloxypropyl phosphate, (meth) acryloxypropyl phosphate, tri ( (Meth) acryloxypropyl phosphate is preferred. One or more of these can be used. Also, a phosphoric acid ester of hydroxyalkyl (meth) acrylate (C)
Unreacted phosphoric acid may remain therein. The hydroxyalkyl (meth) acrylate phosphate (C) is copolymerized with the double bond of polyalkylsilsesquioxane (A) and poly (meth) acrylate (B) during curing to form a coating with good adhesion. It is thought to form a film.

The amount of the hydroxyalkyl (meth) acrylate phosphate (C) used in the present invention is as follows:
Although it depends on the type of the polyalkylsilsesquioxane (A), the amount is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the polyalkylsilsesquioxane (A). If the amount is less than 1 part by mass, sufficient adhesion to the coating film cannot be obtained. If the amount is more than 10 parts by mass, not only is it economically disadvantageous, but also the weather resistance of the film deteriorates.

The polyalkylsilsesquioxane (A) and the poly (meth) acrylate (B) in the present invention
And the mixing ratio of the hydroxyalkyl (meth) acrylate phosphate (C) is 100: 1 to 10 by mass.
0: 1 to 10 are preferred.

The polymerization initiator (D) in the present invention is a radical polymerization initiator that generates a radical by applying heat or a photopolymerization initiator that starts polymerization by irradiating light.

The radical polymerization initiator which generates a radical by heat includes an organic peroxide and an azo compound.

The organic peroxide used in the present invention includes ketone peroxides such as methyl ethyl ketone peroxide, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, and acetylacetone peroxide; -Bis (t-butylperoxy)
3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl-
4,4-bis (t-butylperoxy) valerate,
Peroxy ketals such as 2,2-bis (t-butylperoxy) butane; t-butyl hydroperoxide, cumene hydroperoxide, di-i-propylbenzene hydroperoxide, 2,5-dimethylhexane 2,
Hydroperoxides such as 5-dihydroperoxide and 1,1,3,3-tetramethylbutyl hydroperoxide; di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, α,
α'-bis (t-butylperoxy-i-propyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t Dibutyl peroxide such as -butylperoxy) hexine-3; acetyl peroxide, i-butyryl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,
5,5-trimethylhexanoyl peroxide, succinic peroxide, benzoyl peroxide, 2,4
Diacyl peroxides such as dichlorobenzoyl peroxide; di-i-propylperoxydicarbonate, di-2-ethylhexylperoxydicarbonate, di-n-propylperoxydicarbonate, bis- (4-t-butylcyclohexyl) ) Peroxydicarbonate, dimyristyl peroxydicarbonate, di-2-ethoxyethylperoxydicarbonate, dimethoxy-i-propylperoxydicarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, Peroxy dicarbonates such as diallyl peroxy dicarbonate; t-butyl peroxy acetate, t-butyl peroxy-i-butylate, t-butyl peroxy pivalate, cumyl peroxy neodecanoate, t-butyl perioate Shiraureto, t- butyl peroxybenzoate, cumylperoxy octate, t-hexyl peroxypivalate, peroxy esters such as cumyl peroxy neo-hexanoate; can be used. These may be used alone or in combination of two or more.

In the present invention, the polymerization initiator (D)
May be previously contained in the composition,
It may be added at the time of use.

The azo compounds used in the present invention include azobis-i-butyronitrile, azobismethylbutyronitrile, azobis- (2,4-dimethylvaleronitrile), and 2,2'-azobis- (4-methoxy-2). , 4-
Dimethyl valeronitrile), 1,1′-azobis- (cyclohexane-1-carbonitrile), dimethyl 2,2′-azobisisobutyrate and the like can be used. These may be used alone or in combination of two or more.

As the photopolymerization initiator used in the present invention, acetophenone, propiophenone, benzophenone,
Fluorenone, 3-methylacetophenone, 4,4'-
Dimethoxybenzophenone, 1-hydroxycyclohexylphenone, 2-hydroxyacetophenone, 2,2
-Dimethoxy-1,2-diphenylethan-1-one and the like. These may be used alone or in combination of two or more.

In the coating composition of the present invention, if necessary, a reactive diluent such as a (meth) acrylate monomer, a reactive polymer such as urethane acrylate, a solvent, a thermal condensation inhibitor, a coloring pigment, an extender pigment, Dyes, leveling agents and the like can be blended.

[0030] The coating method of the coating composition of the present invention includes spray coating, roll coating,
Any method such as flow coating and brush coating can be used.

Examples of the apparatus used for curing the composition of the present invention include ovens and infrared lamps for heat curing, and irradiation apparatuses such as ultraviolet fluorescent lamps and mercury lamps for light curing. The temperature, time, irradiation amount and the like in curing can be appropriately selected.

[0032]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Production Examples, Examples and Comparative Examples, but the present invention is not limited to the following Examples.

The physical properties in the examples and comparative examples were measured according to the following methods. (1) Formation of Coating Film Thermosetting Method The coating film thickness after curing by a spray method is 25 to 30 μm on the surface of an SS steel plate substrate previously degreased with a coating composition having a solid content concentration adjusted to 30% by mass. And aged at 120 ° C. for 2 hours to form a cured coating film.

Photocuring Method The coating composition having a solid content adjusted to 30% by mass is preliminarily degreased on the surface of an SS steel substrate so that the coating film thickness after curing by a spray method is 10 to 15 μm. It was applied and irradiated for 3 seconds at a distance of 10 cm using a 2 KW high-pressure mercury lamp to form a cured coating film. (2) Evaluation of Coating Film Adhesion A cross-cut peeling test was performed in accordance with JIS-5400.

Hardness Measurement was carried out with a pencil scratch tester in accordance with JIS-5401.

Heat Resistance The cured coating film was exposed in an oven at 200 ° C. for 48 hours, and evaluated by discoloration of the coating film after cooling at room temperature.

Production Example 1 [Production of polyalkylsilsesquioxane (A1)] γ-methacryloxypropyltrimethoxysilane was placed in a 300 ml flask equipped with a thermometer, a stirrer, a nitrogen inlet tube and a reflux condenser. 84g (100mmo
l), 160.48 g of methyltriethoxysilane (90
0 mmol) and 54.06 g (3,000 mmol) of pure water.
l) was charged, and the solution temperature was maintained at 5 ° C. while stirring under a nitrogen stream. Then, a 3.6 mass% hydrochloric acid aqueous solution 1
After 0.13 g was added dropwise over 30 minutes, the solution temperature was raised to 10
C. for 60 minutes. The solution was heated to 70.degree.
Reaction for 0 minutes, then hexamethylsiloxane 2
4.9 g (153.35 mmol) was added and the silylation reaction was performed at 70 ° C. for 180 minutes. The obtained reaction solution was cooled to 40 ° C., and 13.2 g of a 4.25% by mass aqueous potassium hydroxide solution was added to neutralize the inside of the system, and the system was allowed to stand at room temperature for 12 hours. The lower layer portion of the liquid separated into two layers was collected, and 100 g of butyl acetate was added to the lower layer solution.
After concentrating at 0 ° C./266 hPs and distilling out 100 g of the liquid, 350 g of butyl acetate was further added at room temperature and stirred for 60 minutes. 0.8 μm of the resulting solution
The mixture was filtered through a filter of m to obtain 440 g of a colorless and transparent solution. The number average molecular weight of the obtained organopolysilsesquioxane is determined by GPC (Gel Permeation Ch).
It was 3,500 as measured by a chromatographic method. As a result of the GPC analysis, no peak derived from the raw material silane monomer was detected, and it was considered that the obtained organopolysilsesquioxane contained no unreacted monomer. Also, 1H-, 13C- and 29Si-
From the analysis of the NMR spectrum, the molar ratio of the side chain γ-methacryloxypropyl group and methyl group was equal to the molar ratio of the charged silane monomer, and was 1: 9. This polyalkylsilsesquioxane is hereinafter abbreviated as polymer (A1).

Production Example 2 [Production of polyalkylsilsesquioxane (A2)] Using the same apparatus as for the polymer (A1), 74.51 g of γ-methacryloxypropyltrimethoxysilane (3
00 mmol), 124.8 methyltriethoxysilane.
Except for 2 g (700 mmol), it was produced under the same conditions as in Production Example 1. The number average molecular weight of the obtained organopolysilsesquioxane was 2,500 as measured by GPC. As a result of the GPC analysis, no peak derived from the raw material silane monomer was detected, and it was considered that the obtained organopolysilsesquioxane contained no unreacted monomer. 1H-, 13C- and 29Si-NMR
From the analysis of the spectrum, the molar ratio of the side chain γ-methacryloxypropyl group and methyl group was equal to the molar ratio of the charged silane monomer, and was 3: 7. This polyalkylsilsesquioxane is hereinafter abbreviated as polymer (A2).

Production Example 3 [Production of polyalkylsilsesquioxane (A3)] Using the same apparatus as for the polymer (A1), 22.35 g (90 m) of γ-methacryloxypropyltrimethoxysilane was used.
mol), 160.48 g of methyltriethoxysilane
(900 mmol), phenyltrimethoxysilane 1.
Except for 98 g (10 mmol), the number average molecular weight of the organopolysilsesquioxane produced under the same conditions as in Production Example 1 was 3,000 as measured by GPC. As a result of the GPC analysis, no peak derived from the raw material silane monomer was detected, and it was considered that the obtained organopolysilsesquioxane contained no unreacted monomer. From the analysis of the 1H-, 13C- and 29Si-NMR spectra, the molar ratio of the side chain γ-methacryloxypropyl group, methyl group and phenyl group was 9: 90: 1, which was equal to the molar ratio of the charged silane monomer. . This polyalkylsilsesquioxane is hereinafter abbreviated as polymer (A3).

Example 1 Using the polymer (A1) produced by the above method, 10 parts by mass of trimethylolpropane trimethacrylate and monomethacryloxyethyl phosphate (100 parts by mass of the resin solid content of the polymer (A1)) 3 parts by mass of Kyoeisha Yushi Kagaku Kogyo Co., Ltd .: light ester PM) and 2 parts by mass of benzoyl peroxide as a thermal polymerization initiator were diluted with isopropyl alcohol so that the resin concentration became 30% by mass, A coating composition was obtained.

Using the coating composition, a coating film was formed by a thermosetting method, and the adhesion, hardness and heat resistance were evaluated.

Example 2 Using the polymer (A2) produced by the above method, 10 parts by mass of trimethylolpropane trimethacrylate and 10 parts by mass of pentaerythritol triacrylate per 100 parts by mass of the resin solid content of the polymer (A2). And 5 parts by mass of monomethacryloxyethyl phosphate (manufactured by Kyoeisha Yushi Kagaku Kogyo KK) and 3 parts by mass of benzoyl peroxide as a thermal polymerization initiator, and a resin concentration of 30 parts by mass with isopropyl alcohol. % To obtain a coating composition.

Using the coating composition, a coating film was formed by a thermosetting method and evaluated for adhesion, hardness and heat resistance. Table 1 shows the results.

Example 3 Using the polymer (A3) produced by the above method, 5 parts by mass of trimethylolpropane trimethacrylate and monoacryloxyethyl phosphate (100 parts by mass of the resin solid content of the polymer (A3)) 5 parts by mass of Kyoeisha Yushi Kagaku Kogyo Co., Ltd .: Light Ester PA) and 5 parts by mass of azobisisobutyronitrile as a thermal polymerization initiator are mixed so that the resin concentration becomes 30% by mass with isopropyl alcohol. After dilution, a coating composition was obtained.

The coating composition was used to form a coating film by a thermosetting method, and the adhesion, hardness and heat resistance were evaluated.

Example 4 Using the polymer (A1) produced by the above method, 10 parts by mass of trimethylolpropane trimethacrylate and monomethacryloxyethyl phosphate (100 parts by mass of the resin solid content of the polymer (A1)) 3 parts by mass of Kyoeisha Yushi Kagaku Kogyo Co., Ltd .: Light Ester PM) and 3 parts by mass of 1-hydroxycyclohexylphenone as a photopolymerization initiator are mixed and diluted with isopropyl alcohol so that the resin concentration becomes 30% by mass. Thus, a coating composition was obtained.

Using the coating composition, a coating film was formed by a photocuring method, and the adhesion, hardness and heat resistance were evaluated.

Example 5 Using the polymer (A3) produced by the above method, 10 parts by mass of pentaerythritol tetraacrylate and 100 parts by mass of resin solid content of the polymer (A3), monoacryloxyethyl phosphate (Kyoeisha fats and oils) 8 parts by mass of light ester PA manufactured by Chemical Industry Co., Ltd. and 1-hydroxycyclohexylphenone 8 as a photopolymerization initiator
A part by weight was mixed and diluted with isopropyl alcohol so that the resin concentration became 30% by mass to obtain a coating composition.

Using the coating composition, a coating film was formed by a photocuring method, and the adhesion, hardness and heat resistance were evaluated.

Comparative Example 1 A coating composition was obtained in the same manner as in Example 1 except that the polyalkylsilsesquioxane was not blended.

Using the coating composition, a coating film was formed by a thermosetting method, and the adhesion, hardness and heat resistance were evaluated.

Comparative Example 2 A coating composition was obtained in the same manner as in Example 1 except that trimethylolpropane triacrylate, which was a poly (meth) acrylate, was not used.

Using the coating composition, a coating film was formed by a thermosetting method, and the adhesion, hardness and heat resistance were evaluated.

Comparative Example 3 A coating composition was obtained in the same manner as in Example 1, except that monomethacryloxyethyl phosphate, which is a phosphoric acid ester of hydroxyalkyl (meth) acrylate, was not used.

Using the coating composition, a coating film was formed by a thermosetting method, and the adhesion, hardness and heat resistance were evaluated.

Comparative Example 4 Example 1 was repeated except that benzoyl peroxide, which was a polymerization initiator caused by heat or light, was not used.
A coating composition was obtained in the same manner as described above.

Using the coating composition, a coating film was formed by a thermosetting method, and the adhesion, hardness and heat resistance were evaluated.
However, the curability was poor and the adhesion could not be measured. Table 1 shows the measurement results.

[Table 1]

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshiaki Nagao Haseji, Higashi-Nagahara, Kato-cho, Kawanuma-gun, Fukushima Prefecture F-term in the Showa Denko KK Higashi-Nagahara Plant (reference) 4J038 FA112 FA152 FA211 GA03 GA15 KA03 NA12 NA14

Claims (8)

[Claims] 1. A polyalkylsilsesquiester having a terminal group in which at least 30 mol% is trialkylsilylated and the remainder is an alkoxy group or a hydroxyl group, and an organic group having an ethylenic double bond and an alkyl group in a side chain. Oxane (A),
Poly (meth) acrylate (B) and hydroxyalkyl (meth) acrylate phosphate (C)
A coating composition comprising: 2. The coating composition according to claim 1, comprising a polymerization initiator (D). 3. Polyalkylsilsesquioxane (A)
3. The coating composition according to claim 1, wherein 70% by mole or more of the alkyl group is a methyl group. 4. 4. The method according to claim 1, wherein the hydroxyalkyl (meth) acrylate phosphate (C) is mono (meth) acryloxyethyl phosphate or di (meth) acryloxyethyl phosphate. Coating composition. 5. Polyalkylsilsesquioxane (A)
Is a repeating unit represented by the following general formula (1) and a terminal group represented by the following general formula (2): (Wherein, R ¹ and R ² each independently represent an alkyl group having 1 to 8 carbon atoms or an organic group having an ethylenic double bond, provided that 70 mol% or more represents a methyl group.) ) (Wherein, R ¹ and R ² have the same meanings as above. R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or a trimethylsilyl group, provided that 30 mol%
The above represents a trimethylsilyl group. The coating composition according to claim 3, which is a compound represented by the formula: 6. The compounding ratio of the polyalkylsilsesquioxane (A), the poly (meth) acrylate (B) and the phosphate of the hydroxyalkyl (meth) acrylate (C) is 100: 1 to 1 by mass. 100: 1 ~
The coating composition according to any one of claims 1 to 5, which is 10. 7. A paint comprising the coating composition according to claim 1. 8. A method for improving the surface of a substrate, comprising coating the substrate with the coating composition according to claim 1.