JP3101904B2 - Paint composition and paint finishing method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable coating composition containing a hydroxyl group and an isocyanate group protected in the form of a siloxy group, and more particularly to a scratch-resistant coating composition containing a specific polyisocyanate compound as an essential component. The present invention relates to a coating composition excellent in heat resistance, low-temperature curability, and acid resistance, and a coating finishing method using the same as a top clear. The compositions and methods of the present invention are particularly suitable for use in automotive refinishing.

[0002]

2. Description of the Related Art At present, in the field of automobile repair, two-component acrylic lacquer is used in combination with acrylic polyol and polyfunctional isocyanate curing agent in terms of workability, room temperature curability, finishability and weather resistance. Mold paints are widely used. However, acrylic lacquer has problems such as inferior finish compared to the two-pack type. In the two-pack type, the workability is inferior because the main agent and the curing agent must be combined at the painting site. There is a problem that the excess or deficiency affects the coating film performance and that a large amount of a diluting solvent must be used because the viscosity of the base resin is high due to hydroxyl group hydrogen bonding. To solve these problems, a one-pack type resin composition comprising a siloxy group-containing vinyl polymer instead of a conventional hydroxyl group-containing vinyl polymer and a polyfunctional isocyanate curing agent is used. Although such a method has been proposed (for example, JP-A-3-250016, JP-A-5-5057, etc.), such a resin composition sufficiently satisfies the anti-scratch property recently required for automobile repair. In some cases, the solvent used was inferior in dilution stability and clouded during storage.

[0003]

The object of the present invention is to provide a coating composition which is of a one-part type, has a low viscosity, and is excellent in scratch resistance, storage stability, low-temperature curability and acid resistance. It is to provide.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve such problems, and as a result, have found that a coating composition obtained by mixing a specific polyisocyanate compound with a siloxy group-containing resin is used. They have found that they are extremely effective, and have completed the present invention. The present invention provides: “(a) at least two siloxy groups per molecule;
And weight containing at least one alkoxysilyl group
A resin having an average molecular weight of 1,000 to 200,000 , (b)
Diisocyanate compound and number average molecular weight 500 to 1.5
A coating composition comprising, as essential components, a polyisocyanate compound obtained by reacting polycaprolactone diol and / or triol of No. 00, and (c) a siloxy group dissociation catalyst. 2 . The resin (a) is a vinyl monomer containing a siloxy group, a vinyl monomer containing an alkoxysilyl group, and another vinyl monomer copolymerizable with these monomers. The coating composition according to claim 1, which is a resin obtained by copolymerizing 3 . The resin (a) can be copolymerized with 10 to 60 % by weight of a vinyl monomer containing a siloxy group, 3 to 35 % by weight of a vinyl monomer containing an alkoxysilyl group, and these monomers. Any one of the above items 1 to 2 , which is a resin copolymerized with 5 to 87 % by weight of other vinyl monomers.
The coating composition described in the item. 4 . (B) a polyisocyanate compound as the component is a polyisocyanate compound obtained by reacting at 8-40 in an equivalent ratio of the diisocyanate compound and polycaprolactone diols and / or triols NCO / OH, either no counts 1 to 3 wherein The coating composition according to claim 1. "
About.

[0005]

Hereinafter, the present invention will be described in detail. In the present invention, the siloxy group has the following formula (I)

[0006]

Embedded image

Wherein R ₁ , R ₂ and R ₃ may be the same or different and each represents an alkyl group having 1 to 18 carbon atoms, a phenyl group or an allyl group.

In the present invention, the resin (a) containing at least two siloxy groups in one molecule is usually a vinyl monomer having the siloxy group and another vinyl monomer copolymerizable therewith. It can be obtained by copolymerizing a monomer with a conventional method such as a solution polymerization method in the presence of a radical polymerization initiator. The resin (a) may be a resin further containing at least one alkoxysilyl group from the viewpoint of improving acid resistance and low-temperature curability, and usually a vinyl monomer having a siloxy group and this monomer. Or a vinyl monomer having a siloxy group, a vinyl monomer having an alkoxysilyl group, and another vinyl monomer copolymerizable with these. It is obtained by copolymerizing a monomer with a monomer.

Representative examples of the siloxy group-containing vinyl monomer include, for example, trimethylsiloxyethyl (meth) acrylate, trimethylsiloxypropyl (meth) acrylate, trimethylsiloxybutyl (meth) acrylate, and triethylsiloxyethyl (meth). )
Examples include trialkylsiloxyalkyl (meth) acrylates such as acrylate, triethylsiloxypropyl (meth) acrylate, and triethylsiloxybutyl (meth) acrylate. However, the present invention is not limited to this. Any compound can be used as long as it is converted into a siloxy group with the silylating agent. That is, hydroxyethyl (meth) acrylate with ε-caprolactone added thereto, compounds obtained by converting polyoxyalkylene glycol (meth) acrylates into siloxy groups with silylating agents such as trimethylchlorosilane and t-butyldimethylchlorosilane, etc. Can also be used.

In the present invention, the alkoxysilyl group has the following (II)

[0011]

Embedded image

(Wherein, R ₄ is an alkyl group having 1 to 6 carbon atoms or a phenyl group, R ₅ is an alkyl group having 1 to 4 carbon atoms,
Represents an alkoxysilyl group, and n is 2 or 3).

Representative examples of alkoxysilyl group-containing vinyl monomers include, for example, vinyltrimethoxysilane, vinyltriethoxysilane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) silane
Acryloyloxypropyldimethoxymethylsilane,
γ- (meth) acryloyloxypropyltriethoxysilane, styrylethyltrimethoxysilane, vinyltris (2-methoxyethoxy) silane, vinyltriacetooxysilane, and the like.

Representative examples of other vinyl monomers copolymerizable with the above-mentioned vinyl monomer having a reactive functional group include, for example, styrene, α-methylstyrene, vinyltoluene, and α-chloro. Vinyl aromatic compounds such as styrene; methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, (n-, i-, t-)
Butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n
-Carbon number of acrylic acid or methacrylic acid such as octyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and cyclohexyl (meth) acrylate;
Alkyl or cycloalkyl esters of 4; acrylic acid or methacrylic acid such as methoxybutyl (meth) acrylate, methoxyethyl (meth) acrylate, and ethoxybutyl (meth) acrylate having 2 to 1 carbon atoms;
8 perfluoroalkylethyl (meth) acrylate, perfluoroisononylethyl (meth) acrylate, perfluorooctylethyl (meth) acrylate, and other perfluoroalkyl (meth) acrylates; CF ₂ ＣＦCF ₂ , CHF = CF
₂ , a general formula CX such as CH ₂ = CF ₂ , CC ₁ F = CF _2
2 ＣCX ₂ (wherein X is the same or different and H, C
It represents I, Br, F, an alkyl group or a haloalkyl group.
However, at least one F is contained in the formula. And a so-called macromonomer which is a polymer of one and / or more of these monomers and has a copolymerizable double bond at one end. Examples thereof include a monomer copolymerizable with a vinyl monomer having a group. These can be appropriately selected and used according to desired physical properties.

Solvents used in the solution polymerization of the monomer mixture include, for example, alkylbenzene derivatives such as benzene, toluene and xylene; ethyl acetate, propyl acetate, amyl acetate, methoxybutyl acetate, methyl acetoacetate, ethyl acetoacetate, Acetate solvents such as methyl cellosolve acetate, cellosolve acetate, diethylene glycol monomethyl ether acetate, carbitol acetate;
Ether solvents such as dioxane, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol diethyl ether; acetone,
Examples thereof include ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, and these can be used alone or as a mixture of two or more.

Examples of the radical polymerization initiator include benzoyl peroxide, di-t-butyl hydroperoxide, t-butyl hydroperoxide, cumyl peroxide,
Peroxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, t-butylperoxybenzoate, lauryl peroxide, acetyl peroxide, t-butylperoxy-2-ethylhexanoate; α, α'-azo Examples include azo compounds such as bisisobutyronitrile, α, α'-azobis-2-methylbutyronitrile, azobisdimethylvaleronitrile, and azobiscyclohexanecarbonitrile.

The proportion of each of the above monomers is from 5 to 99% by weight, preferably from 10 to 6% by weight, of a siloxy group-containing vinyl monomer.
0% by weight, alkoxysilyl group-containing vinyl monomer 0
A suitable range is 94% by weight, preferably 3 to 35% by weight, and 1 to 95% by weight, preferably 5 to 87% by weight of other vinyl monomers.

The resin (a) obtained by a usual radical solution polymerization method using the above-mentioned vinyl monomer, solvent and polymerization initiator has a weight average molecular weight of 1,000 to 200,000.
0, more preferably in the range of 2,000 to 100,000. When the weight average molecular weight is less than 1,000, satisfactory drying properties are hardly obtained, and the weather resistance and durability of the obtained coating film tend to decrease. On the other hand, 200,
If it is larger than 000, the finished appearance is undesirably reduced.

In the present invention, the polyisocyanate compound (b) is obtained by reacting a diisocyanate compound with polycaprolactone diol and / or triol. Representative examples of the diisocyanate compound used as the component (b) include, for example, aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate; and hydrogenated xylylene diisocyanate and isophorone diisocyanate. And organic diisocyanates such as organic diisocyanates such as cycloaliphatic diisocyanates. The polycaprolactone diol and / or triol used for the component (b) has a number average molecular weight of 50.
It is desirable to be in the range of 0 to 1500. If the number average molecular weight is less than 500, sufficient flexibility cannot be imparted to a coating film using the component (b) as a curing agent, while if it exceeds 1500, N
This is undesirable because the CO content tends to be low and the coating film performance tends to be poor. The reaction between the diisocyanate compound and polycaprolactone diol and / or triol is as follows:
It is appropriate to carry out with an NCO / OH equivalent ratio of 8 to 40. Examples of the polyisocyanate compound thus obtained include commercially available products such as "Duranate E-402-90T" and "Duranate E-405-80T" (manufactured by Asahi Kasei Corporation).

As the resin component of the present invention, only the resin (a) and the compound (b) are sufficient, but if necessary, a resin containing a siloxy group and an isocyanate group in one molecule, or A resin (d) containing an alkoxysilyl group and an isocyanate group in the molecule, and at least one compound (e) containing two or more siloxy or alkoxysilyl groups in one molecule. , May be appropriately selected and added to the components (a) and (b).

A resin having a siloxy group and an isocyanate group in one molecule, which is used as the component (d);
Alternatively, a resin containing an alkoxysilyl group and an isocyanate group in one molecule is usually a vinyl monomer having each of these reactive functional groups, and another vinyl monomer copolymerizable with these. Similarly to the resin (a), it can be obtained by copolymerization in the presence of a radical polymerization initiator by a conventional method such as a solution polymerization method. The siloxy group or alkoxysilyl group-containing vinyl monomer and other vinyl monomers copolymerizable therewith are appropriately selected from the monomers listed in the structural unit of the resin (a). Typical examples of the isocyanate group-containing vinyl monomer that can be used include, for example, isocyanate ethyl (meth) acrylate, isocyanate propyl (meth) acrylate, and meta-isopropenyl-α, α-dimethylbenzyl isocyanate. However, the present invention is not limited thereto, and an adduct of a hydroxyl group-containing vinyl monomer such as hydroxyethyl (meth) acrylate and a polyfunctional isocyanate compound such as isophorone diisocyanate can also be used. The amount of the component (d) used is desirably 20% by weight or less in terms of the solid content with respect to the component (b) from the viewpoint of scratch resistance.

As the compound having at least two siloxy groups in one molecule, which is used as the component (e), the hydroxyl group of a compound having at least two hydroxyl groups in one molecule may be converted with a known silylating agent. Any compound that has been converted to a siloxy group can be used. Representative examples of these compounds include dihydric alcohols such as ethylene glycol, propylene glycol, 1,2-butanediol, 1,3-butanediol, and 2,3-butanediol; Polylactone diols obtained by adding a lactone such as ε-caprolactone to a polyhydric alcohol; trihydric or higher alcohols such as glycerin, trimethylolpropane, and pentaerythritol; lactone such as ε-caprolactone And the like. Compounds obtained by converting polylactone polyols, etc., to which silyl groups have been added into siloxy groups with a silylating agent such as trimethylchlorosilane or t-butyldimethylchlorosilane, respectively. The component (e) is obtained by copolymerizing the siloxy group-containing vinyl monomers listed in the description of the resin (a) with other vinyl monomers such as styrene and (meth) acrylates. Resin can be used.

Further, used as the above component (e),
Examples of the compound containing at least two alkoxysilyl groups in one molecule include the alkoxysilyl group-containing vinyl monomers listed in the description of the resin (a) and other vinyl compounds such as styrene and (meth) acrylates. Resins obtained by copolymerization with a system monomer can be used.

The above-mentioned resins (a), (b), (d) and (e) can be obtained by mixing these resins with a non-aqueous dispersion type resin (Non-aqueous resin).
aqueenous dispersion (NAD)
May be used. The mixing ratio of the above resins (a) and (b) (and (d) (e)
Component) can be appropriately selected depending on the content of the reactive functional group contained in the resin composition. The siloxy group content in the composition of the present invention is the total amount of the siloxy group-containing vinyl monomer used in the resin (a) and the siloxy group-containing compound of the compound (e) in the resin composition. 5 to 60% by weight based on the solid content, and more preferably 10 to 50%
Preferably it is in the range of weight%. The content is 5
If the amount is less than 10% by weight, the crosslink density of the coating film tends to be low, and the physical properties of the coating film tend to be poor. On the other hand, even if it exceeds 60% by weight, no further improvement in performance can be expected.

The siloxy groups in the composition of the present invention are hydrolyzed by moisture in the air after coating to form hydroxyl groups. Therefore, the composition amounts of the polyisocyanate compound (b) and the isocyanate group-containing vinyl monomer resin and (a) and the siloxy group-containing compound used in the resin composition are as follows:
Hydroxyl groups generated from isocyanate groups and siloxy groups in all resin compositions are NCO / OH = 0.5 to 2.
It is preferable to set the range to 0.

In the present invention, when an alkoxysilyl group is introduced into a resin composition for improving low-temperature curability and acid resistance, the content of the alkoxysilyl group in the composition is controlled by the amount of the alkoxysilyl group-containing vinyl monomer used. The amount of the monomer and the compound (e) as an alkoxysilyl group-containing compound is preferably in the range of 0 to 40% by weight, more preferably 3 to 30% by weight, based on the total solids in the resin composition. .
If the content is more than 40% by weight, the cured coating film tends to be brittle.

The siloxy groups in the composition of the present invention are hydrolyzed by moisture in the air after coating to form hydroxyl groups. In order to promote this hydrolysis reaction, the siloxy group dissociation catalyst (c) is an essential component in the present invention. Representative examples of the compound used as the siloxy group dissociation catalyst (c) include, for example, phosphoric acid and its acidic ester and phosphite; sulfonic acid such as paratoluenesulfonic acid and naphthalenedisulfonic acid and its amine salt; Examples thereof include carboxylic acids such as trichloroacetic acid and trifluoroacetic acid and acidic compounds such as amine salts thereof. When the composition of the present invention is stored for a long period of time, it is desirable to store the catalyst in a container separate from the resin component.

The amount of the siloxy group dissociation catalyst (c) to be added is preferably in the range of 0.01 to 10% by weight, more preferably 0.1 to 5% by weight, based on the solid content of the resin composition. . If the amount is less than 0.01% by weight, the curability decreases,
If it exceeds 10% by weight, the water resistance of the coating film tends to be poor.
The composition of the present invention comprises the above-described resin component and a siloxy group dissociation catalyst, and further includes a known and commonly used urethanization catalyst such as an organotin compound such as dibutyltin dilaurate to promote a reaction between a generated hydroxyl group and an isocyanate group. It may be added in advance.

In order to prevent hydrolysis of siloxy groups and to ensure long-term storage stability, a water-binding agent for capturing moisture may be added to the composition of the present invention. Trialkyl orthoformates such as trimethyl orthoformate, triethyl orthoformate and tributyl orthoformate as water binders; trialkyl orthoacetates such as trimethyl orthoacetate, triethyl orthoacetate and tributyl orthoacetate; and phenyl isocyanate and p-chlorophenylisocyanate , P-
Monoisocyanate compounds such as toluenesulfonyl isocyanate, and commercially available products such as "Additive TI" (manufactured by Sumitomo Bayer Urethane Co., Ltd.) can be used.

Further, in order to improve the physical properties, a cellulose resin such as cellulose acetate butyrate or an epoxy resin may be blended and used. Further, if necessary, pigments (eg, aluminum paste, pearl powder, graphite, metallic pigments such as MIO, organic and inorganic coloring pigments such as titanium oxide and carbon black, extender pigments, etc.), organic solvents, ultraviolet absorbers, It may contain paint additives such as an antioxidant, a surface conditioner, and a dispersant. The composition of the present invention thus obtained can be used as a one-pack type coating material which can be applied only by adjusting the coating viscosity with a diluting solvent.

In the present invention, a base coat paint containing a metallic pigment and / or a color pigment is applied, and then a clear coat paint is applied thereon. The present invention provides a paint finishing method using the coating composition of the present invention. As base coat paint,
Any conventionally known base coat paint containing a metallic pigment and / or a color pigment can be used without any particular limitation, and a lacquer paint containing no crosslinking agent or a curable paint containing a crosslinking agent such as a polyisocyanate compound can be appropriately selected. As a method of applying the base coat paint and the clear coat paint of the present invention, a method known in the field of painting such as spray coating, brush coating, and roller coating can be used.
The base coat has a dry film thickness of about 5 to 60 μm, preferably about 10 to 50 μm, and the clear coat has a dry film thickness of 10 to 10 μm.
The coating is performed on the order of 80 μm, preferably on the order of 20 to 50 μm. As the base coat paint, a lacquer paint containing no crosslinking agent or an acrylic urethane paint containing a crosslinking agent is used.

[0032]

The present invention will be described below in detail with reference to examples. Production of reactive functional group-containing resin

Production Example 1 A reactor was equipped with a thermometer, a thermostat, a stirrer, a reflux condenser, and a dropping pump. 60 parts by weight of xylene was charged and heated to 110 ° C. while stirring. While maintaining 103 parts by weight of the mixture of the polymerization initiator and the polymerization initiator at 110 ° C., the mixture was dropped at a constant rate over 3 hours using a dropping pump. After completion of the dropwise addition, the temperature was maintained at 110 ° C. for 1 hour, and the stirring was continued. Thereafter, a solution prepared by dissolving 0.5 part by weight of an additional polymerization initiator in 5 parts by weight of xylene was added dropwise at a constant rate over 1 hour, and the reaction was terminated at 110 ° C. for 1 hour. The obtained siloxy group- and alkoxysilyl group-containing resin solution was a uniform and transparent solution having a nonvolatile content of 60% by weight and a Gardner viscosity MN. The weight average molecular weight of this resin was 15,000.

Production Examples 2 to 5 The same procedure as in Production Example 1 was carried out except that the mixture of the monomer and the polymerization initiator and the additional polymerization initiator were used as shown in Table 1, and the reactive functional groups were used. A group-containing resin solution was obtained.
Table 2 shows the property values of the obtained resin and resin solution.

[0035]

[Table 1]

(Note) Polymerization initiator: α, α'-azobis-2-methylbutyronitrile Additional polymerization initiator: α, α'-azobis-2-methylbutyronitrile

[0037]

[Table 2]

Examples 1 to 5 and Comparative Examples 1 to 3 The reactive functional group-containing resin solution and catalyst obtained in Production Examples,
Further, the polyisocyanate compounds * 1 to * 3 were mixed and stirred in the composition shown in Table 3 to prepare a clear paint. However, Comparative Example 3 was used as a two-liquid type.

[0039]

[Table 3]

(Note) * 1 Duranate E-405-80T: manufactured by Asahi Kasei Corporation, 80% non-volatile content, 7.1% NCO content,
Polycaprolactone polyol-modified polyisocyanate * 2 Sumidur N-3500: manufactured by Sumitomo Bayer Urethane Co., Ltd., nonvolatile content 100%, NCO content 2
1.6%, isocyanurate type of hexamethylene diisocyanate. * 3 Barnock DN-955: manufactured by Dainippon Ink and Chemicals, 75% non-volatile content, 6% NCO content, alkylenediol-modified polyisocyanate * 4 Dissociation catalyst: diisopropyl phosphate * 5 Urethane-forming catalyst: dibutyltin Dilaurate * 6 Water binder: Trimethyl orthoacetate Next, these clear paints were applied to a thinner having a composition of toluene / xylene / ethyl acetate / butyl acetate = 50/20/10/20/13/14 seconds (Ford cup # 4/2
After adjusting the viscosity to 5 ° C) and applying a clear paint for new cars on a tin plate at room temperature (20 ° C), baking and drying, the resulting coating was spray-coated to a dry film thickness of 40 µm. Table 4 shows the performance test results of the test coated plates thus obtained.

[0041]

[Table 4]

The test method is as follows.

(1) Scratch resistance Dalmac cleanser (Yamasan Shoten) and water were mixed at a ratio of 3: 2 to prepare an abrasive. The tester used was a dye fastness friction tester FR-11 (manufactured by Suga Test Instruments Co., Ltd.). After applying the clear paint for a new car and then baking and drying the coated paint of each example, the coated paint dried at 20 ° C. for 7 days was used as a test plate, and an abrasive was applied to the flannel, and a load of 500 g was applied. The coated surface of the coated plate was rubbed back and forth 20 times. Thereafter, the coated surface was washed with running water and air-dried, and then the 20-degree specular reflectance (20 ° G value) of the coated surface was measured. According to the following equation, 20 ° G
The gloss retention was calculated, and the scratch resistance was evaluated from the value.

[0044]

(Equation 1)

：: 20 ° G gloss retention of 30% or more Δ: 20 ° G gloss retention of 10% or more and less than 30% ×: 20 ° G gloss retention of less than 10%

(2) Acid resistance 40% sulfuric acid was spotted on the coated plate prepared in the same manner as in (1), and the coated surface after heating at 85 ° C. for 30 minutes was evaluated. ：: There is almost no change in the coated surface. エ ッ チ ン グ: Etching has occurred. ×: Significant etching has occurred.

(3) Accelerated weathering resistance The coated plate prepared in the same manner as in (1) was tested with a sunshine weatherometer for 1000 hours, and it was confirmed whether or not the coated surface had changed. ：: There is almost no change on the coated surface.

(4) Gasoline resistance A coated plate prepared in the same manner as in (1) was fixed horizontally, and about 5 cc of regular type gasoline was impregnated into gauze (50 × 50 mm) folded in four, and 3 g Let stand for minutes. Thereafter, the gauze was removed, and the condition of the coated surface after gasoline was wiped off with another gauze was evaluated. ：: There is almost no change in the coated surface ×: Gloss is reduced and softened on the coated surface

(5) Dilution stability In each case, the clear paint was prepared using xylene / ethyl acetate = 90/10
Diluted to 300% using a dilution thinner at 5 ° C.
The paint condition when sealed and stored for 7 days was visually evaluated. ：: No abnormality △: Some white turbid matter is observed ×: White turbid matter is observed or two layers are separated

Examples 6 to 13 and Comparative Examples 4 to 8 Further, "Magiclon" (aminoacrylic resin paint, manufactured by Kansai Paint Co., Ltd.) was applied on the electrodeposited mild steel plate and baked at 140 ° C. for 20 minutes. The coated surface treated with a fine polishing compound was used as a plate to be coated.
The metallic base paints A to D shown in (1) are viscously adjusted with a thinner having the same composition as described above, spray-coated so as to have a dry film thickness of 15 to 20 μm, and left at room temperature for 10 minutes. The paint was spray-coated on the metallic base coating film in a combination shown in Table 5 so as to have a dry film thickness of 40 μm. Table 5 shows the performance test results of the obtained test coated plates.

[0051]

[Table 5]

(Note) * 7 Metallic base paint A: “Acrylic 1101
Metallic base ”, nitrocellulose-modified acrylic lacquer, manufactured by Kansai Paint Co., Ltd. * 8 Metallic base paint B:“ Acrylic 2101
Metallic base ", cellulose acetate butyrate-modified acrylic lacquer, manufactured by Kansai Paint Co., Ltd. * 9 Metallic base paint C:" Retan PG2K1 "
01 metallic base ", two-component acrylic urethane paint, manufactured by Kansai Paint Co., Ltd. * 10 Metallic base paint D:" Standox 5
97 Fine Silver ”, one-pack type lacquer, manufactured by Herberts * 11 Clear lacquer E:“ Aclick 2026G
L Clear ", a cellulose acetate butyrate-modified acrylic lacquer, manufactured by Kansai Paint Co., Ltd. The test methods are as described above and below.

(6) Adhesion After applying each of the metallic base paint and the clear paint of Example on the above-mentioned coated plate, the coated plate dried at 20 ° C. for 7 days was used as a test plate. A cellophane tape was stuck thereon, and the degree of peeling when rapidly peeled off was evaluated. A sample without any peeling was marked with “○”.

(7) Water resistance A test plate prepared in the same manner as in (6) was immersed in tap water (20 ° C.) for 7 days, and the coated surface was visually evaluated for blistering, gloss, and whitening. ：: No abnormality △: Some gloss is seen ×: Swelling, gloss and whitening are seen

(8) Finishing property of the coating film The smoothness and the feeling of holding of the coating film were visually evaluated. ○: good, △:
Somewhat bad.

[0056]

According to the present invention, a two-component composition comprising a combination of a conventional acrylic polyol and a polyfunctional isocyanate curing agent is obtained by forming a resin composition containing a siloxy group-containing resin and a specific polyisocyanate compound as essential components. One-pack type, low-viscosity that cannot be obtained with a one-pack composition consisting of a mold or a siloxy group-containing vinyl polymer and a general polyfunctional isocyanate curing agent, and becomes cloudy during storage due to the solvent used It is possible to obtain a coating composition with good dilution stability and excellent scratch resistance, and further, when an alkoxysilyl group is introduced into the resin composition, it has very good acid resistance and low-temperature curability. An excellent coating composition can be obtained. In addition, by the coating finishing method using the composition of the present invention as a clear coat, in addition to the workability of a conventional clear lacquer, a performance equal to or higher than that of a two-part urethane-curable clear can be realized, and it is particularly useful for repairing automobiles.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-62879 (JP, A) JP-A-62-253670 (JP, A) JP-A-2-189377 (JP, A) JP-A-7- 145325 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 1/00-201/10 C08G 18/00-18/87 C08G 71/00-71/04

Claims (4)

(57) [Claims] 1. A resin having a weight average molecular weight of 1,000 to 200,000 containing at least two siloxy groups and at least one alkoxysilyl group in one molecule .
(B) Diisocyanate compound and number average molecular weight 500 to
A coating composition comprising, as essential components, a polyisocyanate compound obtained by reacting 1,500 polycaprolactone diol and / or triol, and (c) a siloxy group dissociation catalyst. 2. The resin (a) is a vinyl monomer containing a siloxy group, a vinyl monomer containing an alkoxysilyl group, and other vinyl copolymerizable with these monomers. The coating composition according to claim 1, which is a resin copolymerized with a system monomer. 3. A resin (a) comprising 10 to 60 % by weight of a siloxy group-containing vinyl monomer, 3 to 35 % by weight of an alkoxysilyl group-containing vinyl monomer, Other vinyl monomers copolymerizable with the polymer 5 to 87
The coating composition according to any one of claims 1 to 2 , wherein the coating composition is a resin obtained by copolymerizing the resin composition with the resin composition by weight. 4. The polyisocyanate compound of component (b) is a diisocyanate compound and polycaprolactone diol and / or triol in an NCO / OH equivalent ratio of 8%.
The coating composition according to any one of claims 1 to 3 , wherein the coating composition is a polyisocyanate compound obtained by reacting at least one of (a) to (c).