JP2001262013A - Finishing method for coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a finishing method for coating wherein a two-component aqueous surface-adjusting material and a topcoat material are used and whereby a coating film having good finished appearance and excellent in resistance and durability is obtained. SOLUTION: Just before used, an aqueous surface-adjusting material which forms a coating film having a pigment content of 20-70 vol.% and an elongation (at -10 deg.C) of 20% or higher is prepared by mixing a base coating material I-1 containing a pigment and a water-dispersible resin having a hydroxy value of 5 to 100 mgKOH/g, a glass transition temperature of -50 to 0 deg.C, and a wt. average mol.wt. of 20,000-400,000 with a compound cross-linker II-1 having at least two isocyanate groups in a molar ratio of hydroxy groups of I-1 to isocyanate groups of II-1 of 1-0.05-3.0. After the surface-adjusting material is applied, a topcoat material is applied. The topcoat material is prepared by mixing, just before used, an emulsion-base coating material I-2 prepared by the emulsion copolymerization of a mixture comprising 5-60 wt.% cycloalkyl-group-containing polymerizable unsaturated monomer, 5-30 wt.% hydroxy-group-containing polymerizable unsaturated monomer, 10-90 wt.% other polymerizable unsaturated monomer, and an ultraviolet absorber/a light stabilizer with a cross-linker II-2, which is similar to cross-linker II-1, in a molar ratio of hydroxy groups of I-2 to isocyanate groups of II-2 of 0.2-2.0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an exterior coating for a multi-layer coating having a good finished appearance, high durability and high durability using a specific undercoating material and a top coating. The present invention relates to a very useful paint finishing method.

[0002]

2. Description of the Related Art Conventionally, a multi-layer finish coating, in which a decorative unevenness pattern or the like is finished by using a coating material such as a base coat material, a main material, and a top coat material, is generally used for painting a building wall or the like. It has been done. Examples of such a finish coating method include a synthetic resin emulsion-based multi-layer finishing method and a cement-based or polymer-cement-based multi-layer finishing method depending on the type of a main material for pattern formation. In each case, the man-hours and finishes had advantages and disadvantages.

In order to solve the conventional problems, the present applicant has applied a two-layer finish coating method in which an elastic base adjustment material having excellent adhesion to a surface to be coated is applied, and then an overcoat is applied. A proposal has been made (for example, JP-A-6-190332). According to this method, it is possible to simplify a conventional coating process, and to form a highly durable coating film having a good finished appearance and capable of following cracks on a substrate. became.

[0004] However, the above-mentioned base adjustment material has an insufficient elongation in a low-temperature atmosphere, so that it may not be able to follow the crack of the base material in a low-temperature environment such as a cold region, and the coating may be cracked. there were. In order to provide sufficient elasticity even in a low-temperature environment, the undercoating material must have a reduced crosslink density of the coating film, and in this case, there is a problem that water resistance and durability are reduced. On the other hand, in recent years, a coating film having higher weather resistance has also been required for the overcoating film.

[0005]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a two-part type isocyanate-cured coating material having a specific composition is used as a base adjustment material and a top coating material. As a result, they have found that high elasticity and a high crosslinking density can be achieved at the same time even in a low-temperature environment, and that a coating film with high weather resistance can be formed, and the present invention has been completed.

That is, according to the present invention, (A) a hydroxyl value of 5 to 100 mgKOH / g, a glass transition temperature of -50 to 0
At least two isocyanate groups per molecule in a water-dispersible resin having a weight-average molecular weight of 20,000 to 400,000 and a pigment (B) containing a pigment (I-1). A crosslinking agent (II-1) containing a compound containing
Immediately before use, the isocyanate group contained in the crosslinking agent (II-1) is 0.05 to 3.0 mol with respect to 1 mol of the hydroxyl group contained in the base paint (I-1). An aqueous paint obtained by mixing, the pigment has a volume concentration of 20 to 70% in the formed coating film, and the formed coating film has an elongation of -10 ° C.
(C) (a) 5 to 60% by weight of a polymerizable unsaturated monomer having a cycloalkyl group, and (b) a hydroxyl group. A monomer mixture comprising 5 to 30% by weight of a polymerizable unsaturated monomer and (c) 10 to 90% by weight of another polymerizable unsaturated monomer; and (d) an ultraviolet absorber and / or photostable. Paint (I-2) containing a copolymer emulsion containing an ultraviolet absorber and / or a light stabilizer as a main component, which is obtained by emulsion polymerization of a mixture with a base material, and at least two base coats per molecule. The crosslinking agent (II-2) containing the above-mentioned compound containing an isocyanate group is contained in the crosslinking agent (II-2) with respect to 1 mol of the hydroxyl group contained in the base coating material (I-2). Immediately before use so that the isocyanate group to be used is in the range of 0.2 to 3.0 mol. It is intended to provide a paint finishing method in which a two-component aqueous topcoat is applied.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The two-part aqueous base conditioner used in the method of the present invention comprises one molecule of a base paint (I-1) containing (A) a water-dispersible resin and (B) a pigment. It is an aqueous coating obtained by mixing a crosslinking agent (II-1) containing a compound containing at least two or more isocyanate groups immediately before use.

The water-dispersible resin (A) used for the base coating material (I-1) in the two-component aqueous base conditioner has a hydroxyl value of 5 to 100 mgKOH / g, preferably 10 to 50 mgKOH / g.
mg KOH / g, glass transition temperature -50 to 0 ° C, preferably -40 to 0 ° C, weight average molecular weight 20,000 to 4
00,000, preferably 20,000 to 300,00
Acrylic, polyester, polyurethane, silicone, fluorine, etc. polyol resins, preferably hydroxyl-containing polymerizable unsaturated monomers and other polymerizable unsaturated copolymerizable therewith. It is an emulsion of an acrylic copolymer obtained by emulsion-polymerizing a monomer mixture containing a monomer in the presence of an emulsifier.

The water-dispersible resin (A) has a hydroxyl value of 5 m
If it is less than gKOH / g, the crosslinking point is poor and the physical properties of the coating film are insufficient. On the other hand, if it exceeds 100 mgKOH / g, the initial water resistance is lowered and the viscosity of the coating material is increased, so that the coating workability is also undesirably reduced.

When the glass transition temperature of the water-dispersible resin (A) is lower than -50 ° C., the strength and water resistance of the formed film are reduced. This is not preferable because cracks and the like of the base material cannot be followed and cracks and the like easily occur. When the weight-average molecular weight of the water-dispersible resin (A) is less than 20,000, the formed film is inferior in weather resistance and water resistance.
If it exceeds 0, it is inferior in compatibility with other paint components and has a film forming property.
It is not desirable because the curability decreases.

The hydroxyl group-containing unsaturated monomer used for producing the preferred acrylic copolymer includes, for example, 2-
C1-C6 hydroxyalkyl esters of acrylic acid or methacrylic acid such as hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether Ters; equimolar adducts of polyetherpolyols such as ethylene glycol and the like (polycarbonates having 2 to 20 carbon atoms) and polyethylene glycol and unsaturated carboxylic acids such as (meth) acrylic acid; Monoethers of a polyether polyol such as polyethylene glycol and a hydroxyl group-containing monomer such as 2-hydroxyethyl (meth) acrylate are mentioned.
The species or two or more species can be appropriately selected and used.

Other polymerizable unsaturated monomers used in the production of the copolymer include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, and n-butyl (meth) acrylate. G, i-butyl (meth) acryle
Acrylic acid such as tert-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate; C1-C24 alkyl ester or cycloalkyl ester of methacrylic acid; unsaturated carboxylic acid such as (meth) acrylic acid, sulfoethyl (meth) acrylate and its sodium or ammonium salt; dimethylaminoethyl (meth) acryle -(Meth) acrylamide;
Vinyl aromatic compounds such as styrene, α-methylstyrene and vinyltoluene; vinyl acetate, vinyl chloride, vinyl ether, (meth) acrylonitrile; alkoxy such as vinyltrimethoxysilane and γ- (meth) acryloyloxypropyltrimethoxysilane A silyl group-containing monomer; perfluorobutylethyl (meth) acrylate,
Perfluoroalkyl (meth) acrylates such as perfluorooctylethyl (meth) acrylate; fluoroolefins; and one or more of these can be appropriately selected and used.

The water-dispersible resin (A) is contained in the vehicle component of the base coating material (I-1) in a solid content of at least 20% by weight, preferably at least 50% by weight, more preferably at least 80% by weight.
% By weight or more. If the content is less than 20% by weight, it is not preferable because sufficient coating properties such as water resistance and durability cannot be obtained.

Other resin emulsions optionally used as a vehicle component of the base paint (I-1) include, for example, vinyl acetate emulsion, acrylic resin emulsion, vinegar-acrylic emulsion, ethylene-vinegar. Bi emulsion, silicone acrylic emulsion,
Epoxy resin emulsions, urethane resin emulsions, alkyd resin emulsions, polyurethane emulsions and the like, as well as water-soluble resins used in combination, water-soluble acrylic resins, polyvinyl alcohol, natural or synthetic rubber latex, and the like. Can be used by appropriately selecting one or more kinds.

The pigment (B) used in the base paint (I-1) includes, for example, coloring pigments such as titanium oxide, carbon black and red iron oxide, calcium carbonate, talc, mica, clay, silica, and the like. Examples include extender pigments such as diatomaceous earth, silica sand, and pearlite, and aggregates, which can be appropriately selected and used.

The pigment (B) is blended so that the pigment has a volume concentration of 20 to 70%, preferably 30 to 60%, in the coating film to be formed. There is a need. Here, "Pigment volume concentration (PV
"C)" is the volume ratio of the pigment to the solid content of the mixture of the resin and the pigment. If the PVC content is less than 20%, the resulting coating film has a poor feeling of holding, and the substrate adjustment ability is reduced.
If the VC is more than 70%, the denseness of the coating film obtained is reduced, and if a top coat is applied on the coating film, suction unevenness of the top coating material is liable to occur, and a good finished appearance cannot be obtained. This is not preferred because the physical properties of the film also deteriorate.

The base paint (I-1) may further contain a pigment dispersant, a curing catalyst, an antifoaming agent, a thickener, a film-forming auxiliary, a preservative, an antifreezing agent, an organic solvent, if necessary. And the like.

Among them, as the curing catalyst, a conventionally known curing catalyst can be used without particular limitation, for example, triethylamine,
Amine catalysts such as tripropylamine, tributylamine, diethanolamine and triethanolamine; dibutyltin dilaurate, dibutyltin oxide, tin octylate, lead naphthenate, and cobalt naphthenate can be used; For example, polyethers, copolymers of polysiloxane and polyether, condensates of polysiloxane and silicic acid, and metal soaps can be used.

The crosslinking agent (II
-1) represents at least two or more isocyanates in one molecule.
And a compound containing a cross-linking agent (II
As -1), a polyisocyanate compound containing at least two or more isocyanate groups in one molecule is added to the base paint (I-1) as it is or by using it together with a surfactant and stirred. The polyisocyanate compound is preferably used after being modified with a surfactant or the like from the viewpoint of water dispersibility. As such a modified product, any one obtained by introducing a hydrophilic chain by a conventionally known method can be used without particular limitation. For example, (i) a reaction product of an alkoxypolyalkylene glycol and a polyisocyanate compound, (Ii) a mixture of an emulsifier obtained by reacting a polyisocyanate compound with an alkoxypolyalkylene glycol and a dialkanolamine, and a polyisocyanate compound;
And (iii) a reaction product or mixture of the above (i) or (ii) with a silane coupling agent having a hydroxyl group or an amino group at one end and an alkoxysilyl group at the other end, and the like. It can be appropriately selected and used.

Examples of the polyisocyanate compound include aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and isophorone diisocyanate. Alicyclic diisocyanates such as 4.4'-methylenebis (cyclohexyl isocyanate) and isophorone diisocyanate; xylylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate; And aromatic diisocyanates such as polyphenylmethane diisocyanate (hereinafter referred to as polymeric MDI); and similar compounds such as isocyanurates and burettes. These may be used alone or in combination of two or more. Can be used.

The reaction product (i) of the above polyisocyanate compound with an alkoxypolyalkylene glycol is
A water-dispersible polyisocyanate which is reacted so that the residual isocyanate content becomes 20 to 30% by weight. Specifically, the above-mentioned polyisocyanate compound and alkoxypolyalkylene glycol are mixed with isocyanate. −
And the equivalent ratio of g-hydroxyl group is 3 to 30, preferably 10 to 25.
It is appropriate to make the reaction to a degree. The alkoxypolyalkylene glycol has a general formula of R ₁ O—
(R ₂ O) _n -H (where R ₁ is an alkyl group, R ₂ is an alkylene group, and n is 2 to 100),
For example, methoxypolymethylene ether glycol, methoxypolyethylene ether glycol, ethoxypolyethylene ether glycol, ethoxypolybutylene ether
Terglycol and the like.
Those having a range of 000, preferably 400 to 2,000 can be used.

A mixture (ii) of an emulsifier obtained by reacting the above-mentioned polyisocyanate compound with an alkoxypolyalkylene glycol and a dialkanolamine, and a polyisocyanate compound are water-dispersible polyisocyanate compositions. It is suitable that the emulsifier and the polyisocyanate compound are mixed so that the isocyanate content is 3 to 50% by weight, preferably 5 to 30% by weight. You may leave.

The emulsifier comprises a polyisocyanate compound and an alkoxypolyalkylene glycol, which is an isocyanate compound.
And the equivalent ratio of (g) group / hydroxyl group is 3 to 30, preferably 10 to 2
After the reaction, the unreacted polyisocyanate compound is removed, and then the dialkanolamine is converted to an isocyanate group / amino group equivalent ratio of 0.5-2, preferably 0.8-1. It is obtained by reacting to about 0.2. As the alkoxypolyalkylene glycol used in the production of the emulsifier, the same ones as described in the above (i) can be used. As the dialkanolamine, for example, dimethanolamine, diethanolamine, diisopropanolamine, diethanolaniline Etc. can be used.

The reaction product or mixture (iii) of the above (i) or (ii) with a silane coupling agent having a hydroxyl group or an amino group at one end and an alkoxysilyl group at the other end is the above (i) Or (ii) a hydroxyl group or an amino group of a silane coupling agent is added to an isocyanate group of a water-dispersible hydrolyzed polyisocyanate.
And the residual isocyanate content obtained by reacting at an equivalent ratio of tri-hydroxyl group or amino group of 3 to 30 is 3
５０50% by weight, preferably 5-30% by weight, of reaction products or mixtures. If the content is less than 3% by weight, the water resistance of the resulting coating film is inferior.

Examples of the silane coupling agent include N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-aminopropyl Triethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane and the like. Further, the alkoxy polyalkylene glyco-
The same thing as the above (i) can be used as the file.

Among the above (i) to (iii), the crosslinking agent (II-
As (1), (iii) in which hydrophilicity and hydrophobicity are balanced from the viewpoint of stability particularly when dispersed in water is preferable.

As described above, the two-part aqueous base conditioner comprises the above base paint (I-1) and a crosslinking agent (II-1),
These are the isocyanates contained in the crosslinking agent (II-1) per mole of hydroxyl groups contained in the base paint (I-1).
Group is 0.05 to 3.0 mol, preferably 0.1 to 2.
Mix immediately before use so that it will be 5 mol, and use for use.

The elongation percentage of the coating film formed by the two-component aqueous base conditioner must be 20% or more, preferably 30 to 100% in a -10 ° C. atmosphere.
30% or more, preferably 50 to 300% in a 0 ° C atmosphere
It is desirable that Here, the elongation percentage of the coating film is measured using a universal tensile tester equipped with a thermostat (Autograph AG2 manufactured by Shimadzu Corporation).
000B) at -10 ° C and 20 ° C at a tensile speed of 200 mm / min. The sample used for the measurement was prepared in accordance with JIS A 6909. If the elongation is less than these, it is not preferable because it cannot follow cracks in the substrate.

Next, the two-pack aqueous topcoat used in the method of the present invention comprises a polymerizable unsaturated monomer having a cycloalkyl group (a), a hydroxyl group-containing polymerizable unsaturated monomer (b) and other polymerizable monomers. A UV absorber and / or a light stabilizer obtained by emulsion polymerization of a mixture of a monomer mixture composed of the unsaturated monomer (c) and a UV absorber and / or a light stabilizer (d). A base coating composition (I-2) containing a copolymer emulsion (C) as a main component, containing a crosslinking agent (II-2) containing a compound containing at least two or more isocyanate groups in one molecule. , A water-based paint mixed immediately before use.

Examples of the polymerizable unsaturated monomer (a) having a cycloalkyl group include cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, and t-butylcyclohexyl (meth) acrylate. , Cyclododecyl (meth) acrylate and the like, and one or more of them can be appropriately selected and used.

Examples of the hydroxyl group-containing polymerizable unsaturated monomer (b) include 2-hydroxyethyl (meth) acrylic acid.
C1-C6 hydroxyalkyl esters of acrylic acid or methacrylic acid, such as 2-hydroxypropyl (meth) acrylate; hydroxyalkyl vinyl ethers, such as hydroxyethyl vinyl ether; ethylene glycol Equimolar adducts of polyether polyols such as polyethylene glycol (2-20 carbon atoms) and unsaturated carboxylic acids such as (meth) acrylic acid; polyethers such as polyethylene glycol And monoethers of terpolyol and a hydroxyl group-containing monomer such as 2-hydroxyethyl (meth) acrylate. One or more of these can be appropriately selected and used.

Other polymerizable unsaturated monomers (c) include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate,
i-butyl (meth) acrylate, t-butyl (meth)
Acrylate, 2-ethylhexyl (meth) acrylate
C1-C24 alkyl esters of acrylic acid or methacrylic acid, such as tert-lauryl (meth) acrylate and isobornyl (meth) acrylate; unsaturated carboxylic acids, such as (meth) acrylic acid, and sulfoethyl (meth) Acrylate and its sodium or ammonium salt;
Dimethylaminoethyl (meth) acrylate, (meth)
Acrylamide; styrene, α-methylstyrene, vinyl aromatic compounds such as vinyltoluene; vinyl acetate, vinyl chloride, vinyl ether, (meth) acrylonitrile;
Alkoxysilyl group-containing monomers such as vinyltrimethoxysilane and γ- (meth) acryloyloxypropyltrimethoxysilane; perfluorobutylethyl (meth)
Acrylates, perfluoroalkyl (meth) acrylates such as perfluorooctylethyl (meth) acrylate; and fluoroolefins.
The species or two or more species can be appropriately selected and used.

Each content in the above monomer mixture is represented by (a)
Is 5 to 60% by weight, preferably 5 to 30% by weight, (b)
Is in the range of 5 to 30% by weight, preferably 5 to 20% by weight, and (c) is in the range of 10 to 90% by weight, preferably 50 to 90% by weight. When the content of (a) is less than 5% by weight, a coating film having sufficiently high weather resistance cannot be obtained.
When the content is more than 5% by weight, cracks easily occur in the coating film with the passage of time. When the content of the monomer (b) is less than 5% by weight, the properties of the coating film become insufficient. It is not preferable because the initial water resistance of the coating film is reduced and the viscosity of the coating material is increased, so that the coating workability may be reduced.

UV absorber and / or light stabilizer (d)
Is added simultaneously during the emulsion polymerization of the monomer mixture,
It is contained in the obtained emulsion particles by being soaked therein, and thus exhibits its effect without being eluted by rainwater or the like after the formation of the coating film.

As the ultraviolet absorber and / or light stabilizer (d), conventionally known ones can be used.
Examples of the ultraviolet absorber include salicylic acid derivatives such as phenyl salicylate, p-octylphenyl salicylate and 4-t-butylphenyl salicylate; 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 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-octadecyloxybenzophenone, 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
Benzophenones such as -methacryloxy-2-hydroxypropoxy) benzophenone; benzotriazoles such as 2- (2'-hydroxy-5'-methylphenyl) benzotriazole and others (anilide oxalate, cyanoacrylate, etc.) The light stabilizer is a hindered amine derivative, specifically, bis- (2,2 ′, 6,6′-tetramethyl-
4-piperidinyl) sebate, 4-benzoyloxy-2,2 ', 6,6'-tetramethylpiperidine and the like, and one or more of these can be appropriately selected and used.

The UV absorber and / or light stabilizer (d) is used in an amount of 0.1 to 5 parts by weight, preferably 0 to 5 parts by weight, based on 100 parts by weight of the monomer mixture in solid content. 0.5 to 3 parts by weight, the light stabilizer is 0.1 to 3 parts by weight,
Preferably, the amount is in the range of 0.5 to 2 parts by weight.

Emulsion polymerization of a mixture of the above monomer mixture and an ultraviolet absorber and / or a light stabilizer (d) can be carried out by a conventionally known method. For example, a polymerization initiator is used in the presence of an emulsifier. Can be done. Examples of the emulsifier include anionic surfactants and nonionic surfactants, and examples of the polymerization initiator include persulfates and peroxides.

The copolymer emulsion (C) obtained as described above has a weight average molecular weight of 1,000 to 200,000.
0, the glass transition temperature is preferably in the range of -10 to 80 ° C, and the particle size of the emulsion is 100 to 2
It is desirable to be within the range of 00 nm.

In the present invention, after the emulsion polymerization of the copolymer emulsion (C) obtained as described above, one or both of an alkoxysilane compound and a low-molecular-weight organosiloxane compound are added and a condensation reaction is performed. To be a siloxane composite copolymer emulsion,
It is preferable from the viewpoint of imparting further high weather resistance to the obtained coating film.

The alkoxysilane compound and the organosiloxane compound are represented by the general formulas RnSi (OR1) 4-n and RmSiO (4-m) / 2, respectively.

In the above formula, n represents an integer of 0 to 3, m represents an average value of 1 to 3, and R represents an organic group having 1 to 8 carbon atoms, such as a methyl group, an ethyl group, and n-propyl. Group, alkyl group such as i-propyl group, γ-chloropropyl group, vinyl group, 3,3,3
-Trifluoropropyl group, γ-glycidoxypropyl group,
γ-methacryloxypropyl group, γ-mercaptopropyl group, phenyl group, 3,4-epoxycyclohexylethyl group, γ-aminopropyl group and the like. Also R1
Is an alkyl group having 1 to 5 carbon atoms or an acyl group having 1 to 4 carbon atoms, for example, a methyl group, an ethyl group, an n-propyl group,
Examples thereof include an n-butyl group, a sec-butyl group, a tert-butyl group, and an acetyl group. If the carbon number of R or R1 is too large, the water solubility becomes low, and the absorptivity to the emulsion particles decreases, which is not preferable.

Specific examples of the above alkoxysilane compounds include, for example, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrisilane. Methoxysilane, n-propyltriethoxysilane, i-propyltrimethoxysilane, i-propyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane,
γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, phenyltrimethoxysilane,
Phenyltriethoxysilane, γ-aminopropyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, and the like, among which methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane,
Phenyltriethoxysilane and the like are preferred.

Specific examples of the organosiloxane compound include, for example, “MKC silicate MS-51” (manufactured by Mitsubishi Chemical Corporation), “MKC silicate MS-56” (manufactured by Mitsubishi Chemical Corporation),
Organosiloxane oligomers such as "ethyl silicate 48" (manufactured by Tama Chemical Co., Ltd.); and cyclic compounds such as octamethylcyclotetrasiloxane or decamethylcyclopentasiloxane, tetramethylcyclotetrasiloxane, and tetravinyltetramethylcyclotetrasiloxane. . These alkoxysilane compounds and organosiloxane compounds can be used alone or in combination of two or more.

The amount of the alkoxysilane compound and organosiloxane compound to be subjected to the condensation reaction in the presence of the emulsion particles is 0.1 to 200 parts by weight, preferably 10 to 80 parts by weight, per 100 parts by weight of the solid content of the emulsion particles.
A range of parts by weight is suitable. If less than 0.1 parts by weight,
The expected performance is not sufficiently exhibited. On the other hand, if it exceeds 200 parts by weight, the polymerization stability becomes extremely poor, which is not preferable.

As a method for allowing the emulsion particles to absorb the alkoxysilane compound and the organosiloxane compound, the emulsion particles are easily dispersed by adding the alkoxysilane compound and the organosiloxane compound to an aqueous dispersion in which the emulsion particles are dispersed, and stirring the emulsion particles well. Achieved. The addition method is a method in which the whole amount is added all at once, or a part or the whole amount is added continuously or intermittently. In order to avoid the reaction proceeding in a state where the absorption of the alkoxysilane compound and the organosiloxane compound is not sufficient, the emulsion particles have a pH of 4 to 10, preferably a pH of 4 to 10.
Adjust to 5-9, temperature is 90 ° C or less, preferably 70 ° C
Or less, more preferably 50 ° C. or less, particularly preferably 3 ° C.
It is desirable to add and absorb the alkoxysilane compound and the organosiloxane compound under the condition of 0 ° C. or lower.

The condensation reaction of the alkoxysilane compound and the organosiloxane compound absorbed in the emulsion particles can be easily controlled by changing the reaction temperature and the hydrogen ion concentration, and the degree of polymerization of the polysiloxane can be controlled. The condensation reaction can be carried out at a temperature of 30 ° C. or higher, preferably 50 ° C. or higher, more preferably 70 ° C. or higher. When the emulsion particles have an alkoxysilyl group, the grafting reaction between the copolymer of the emulsion particles and the polysiloxane proceeds simultaneously under the above conditions.

The base paint (I-2) contains the above-mentioned copolymer emulsion (C) as a main component, and if necessary, is fused with the above-mentioned copolymer emulsion (C) in a dispersed state. A copolymer emulsion (D) containing a hydroxyl group that is difficult to mix is blended so that (D) is 2 to 30 parts by weight, preferably 5 to 15 parts by weight, based on 100 parts by weight of the resin solid content (C). be able to. Two-part isocyanate
In a water-curable water-based paint, after the main agent and the cross-linking agent are mixed, the cross-linking agent component permeates into the emulsion particles in the base paint over time, and the cross-linking takes precedence within the particles. The emulsion (D)
Due to the presence of the particles, the crosslinking agent component described below that soaks into the particles of the copolymer emulsion (C) is added to the emulsion (D).
In addition, since a crosslinking reaction takes place, a chain is formed between the emulsion particles and gelation occurs, and the pot life can be visualized and misuse can be prevented.

From the viewpoint of water resistance and weather resistance, the emulsion (D) specifically has a particle diameter of (D-1) 1/2 or less of the copolymer emulsion (C) and a weight average molecular weight. At least one of an acrylic copolymer emulsion, (D-2) silicon-based emulsion, and (D-3) fluorine-based emulsion which is 100,000 or more larger than the copolymer emulsion (C) can be selected.

Acrylic copolymer emulsion (D-1)
Are small particles having a particle size of 1/2 or less, preferably 1/3 or less of the emulsion (C), and having a weight average molecular weight of 10% lower than that of the resin of the emulsion (C).
It is desired that the difference be greater than 10,000, preferably greater than 200,000. If the difference between the particle diameter and the weight average molecular weight is less than this, it is not desirable because the emulsion (C) is easily fused even in a dispersed state and a chain between emulsion particles cannot be formed.

The above acrylic copolymer emulsion (D-
1) is usually obtained by emulsion-polymerizing a monomer mixture containing a hydroxyl group-containing polymerizable unsaturated monomer and another polymerizable unsaturated monomer copolymerizable therewith in the presence of an emulsifier. . The hydroxyl group-containing polymerizable unsaturated monomer and another polymerizable unsaturated monomer copolymerizable therewith can be appropriately selected from those listed in the description of the copolymer emulsion (C), Usually, it is desirable that the monomer composition of the copolymer emulsion (C) is different.

Examples of the silicon-based emulsion (D-2) include a silicone-based emulsion having an alkoxysilyl group introduced therein, and include an alkoxysilyl-group-containing polymerizable unsaturated monomer and a hydroxyl-group-containing polymerizable unsaturated monomer. An emulsion of an alkoxysilyl group-containing copolymer obtained by copolymerizing a monomer mixture containing a polymer and another copolymerizable polymerizable unsaturated monomer is preferable. The alkoxysilyl group-containing polymerizable unsaturated monomer, the hydroxyl group-containing polymerizable unsaturated monomer, and other copolymerizable polymerizable unsaturated monomers are listed in the description of the copolymer emulsion (C). It can be appropriately selected from among them.

The above silicon emulsion (D-2)
Is preferably smaller than the particle diameter of the copolymer emulsion (C) in the range of 50 to 200 μm.

The fluorine-based emulsion (D-3) includes, for example, a polymerizable unsaturated monomer containing a fluorine group such as a fluoroalkyl group, a polymerizable unsaturated monomer containing a hydroxyl group, and other copolymerizable polymers. An emulsion of a fluorine group-containing copolymer obtained by copolymerizing a monomer mixture containing a unsaturated monomer is preferable. The fluorine-containing polymerizable unsaturated monomer, the hydroxyl-containing polymerizable unsaturated monomer, and other copolymerizable polymerizable unsaturated monomers are listed in the description of the copolymer emulsion (C). Can be selected as appropriate.

The fluorine-based emulsion (D-3) is
It is desirable that the particle size is in the range of 50 to 200 μm and smaller than the particle size of the copolymer emulsion (C).

The base paint (I-2) may further contain, if necessary, pigments such as coloring pigments and extenders, pigment dispersants, film-forming auxiliaries, curing catalysts, defoamers, thickeners. , A preservative, an antifreezing agent, an organic solvent and the like.

The crosslinking agent (II-
2) includes a compound containing at least two or more isocyanate groups in one molecule, and the crosslinking agent (II-
2) can be appropriately selected from those listed in the description of the crosslinking agent (II-1).

As described above, the two-pack aqueous topcoat comprises the above base paint (I-2) and a crosslinking agent (II-2), which are contained in the base paint (I-2). Immediately before use, the isocyanate group contained in the crosslinking agent (II-2) is mixed in an amount of 0.2 to 3.0 mol, preferably 0.5 to 2.5 mol per 1 mol of the hydroxyl group. Serve for use.

In the method of the present invention, the two-component aqueous base coat obtained as described above is applied as an elastic base paint on the surface to be coated, and then the two-pack aqueous topcoat obtained as described above is applied thereon. It is a paint finishing method to finish.

The surface to be coated can be applied to the surface of a conventionally known substrate or the surface of an old coating film. The substrate is not particularly limited, but may be, for example, a concrete surface, a mortar surface, or a slate plate. , PC board, ALC board, concrete block surface, wood, stone, plastic, metal, etc. As the old coating film, acrylic resin, acrylic urethane resin, polyurethane resin based on these substrates , Fluororesin, silicon acrylic resin, vinyl acetate resin, etc. It is preferable that each of them is appropriately subjected to substrate adjustment and, if necessary, primer coating.

[0060] In the method of finishing the coating of the present invention, the two-pack type aqueous base conditioner is applied to the surface to be coated with a roller, an air spray,
An elastic base coating layer is formed by coating using a known coating tool such as an airless spray, a ricin gun, a universal gun, a brush, and the like, and then the above-mentioned two-pack aqueous topcoat is formed on the coated surface in the same manner as described above. To form a top coat layer by coating with a coating tool.

In the method of the present invention, the application amount of the two-component aqueous base conditioner is suitably 0.2 to 1.5 kg / m ² , preferably 0.3 to 1.3 kg / m ² . It is preferable that the paint is applied so that the surface to be coated is formed into a smooth surface or a smooth uneven surface (pattern such as citron skin or creter). The amount of the two-component water-based top coat is suitably about 0.1 to 0.5 kg / m ² .

[0062]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. “Parts” and “%” are “parts by weight” respectively.
And "% by weight".

Production Example 1 of Copolymer Emulsion 309 parts of deionized water was placed in a two-liter four-necked flask equipped with a stirrer, a thermometer, a reflux tube, and a nitrogen inlet tube.
1.1 parts of col707SF (manufactured by Nippon Emulsifier Co., anionic surfactant, nonvolatile content: 30%) was added, and the mixture was replaced with nitrogen and kept at 85 ° C. with stirring. To this, 21 parts of the pre-emulsion obtained by emulsifying the following composition and 0.32 parts of ammonium persulfate were added, and 20 minutes after the addition, the remaining pre-emulsion was added dropwise over 4 hours.

Deionized water 325 parts Newcol 707SF 43.3 Methyl methacrylate 24 Styrene 24 N-butyl methacrylate 530 2-Ethylhexyl methacrylate 33 2-Hydroxyethyl methacrylate 32.5〃 Acrylic acid 6.5〃 Ammonium persulfate 1.5〃 After maintaining at 85 ° C. for 2 hours from the end of dropping, the temperature was lowered to 40 ° C. Adjust the pH to 8.5 with aqueous ammonia and adjust the solid content to 50.
%, A weight average molecular weight of 120,000, and a glass transition temperature of -40 ° C. to obtain a copolymer emulsion (A).

Production Example 2 309 parts of deionized water was placed in a two-liter four-necked flask equipped with a stirrer, a thermometer, a reflux tube, and a nitrogen inlet tube.
After adding 0.8 part of col707SF (manufactured by Nippon Emulsifier Co., anionic surfactant, nonvolatile content: 30%), the mixture was replaced with nitrogen and kept at 82 ° C. with stirring. To this, 21 parts of the pre-emulsion obtained by emulsifying the following composition and 0.25 parts of ammonium persulfate were added, and 20 minutes after the addition, the remaining pre-emulsion was dropped over 4 hours.

Deionized water 85 parts Newcol 707SF 0.5 {Styrene 20} Cyclohexyl methacrylate 15} Methyl methacrylate 22 {N-butyl methacrylate 17} 2-Ethylhexyl acrylate 15} 2-Hydroxyethyl Methacrylate 10 〃 Acrylic acid 1 〃 Octyl mercaptan 1 〃 “TINUVIN 384-2” (Note 1) 2 〃 “TINUVIN 123” (Note 2) 1 ア ン モ ニ ウ ム Ammonium persulfate 0.25〃 82 hours at the end of dropping at 82 ° C. After that, the temperature was lowered to 40 ° C. The pH was adjusted to 8.5 with aqueous ammonia to obtain a copolymer emulsion (C-1) having a solid content of 51%, a weight average molecular weight of 120,000 and a particle diameter of 170 nm. (Note 1) "TINUVIN 384-2": a benzotriazole-based ultraviolet absorber manufactured by Ciba Specialty Chemicals, Inc. (Note 2) "TINUVIN 123": a light stabilizer manufactured by Ciba Specialty Chemicals, Manufacturing Example 3 In Manufacturing Example 2, The same operation as in Production Example 2 was carried out except that the amount of the monomer and the amount of the catalyst in the pre-emulsion were as described below, and a copolymer emulsion (C-2) having a solid content of 52%, a weight average molecular weight of 120,000 and a particle diameter of 170 nm was used. ) Got.

Deionized water 85 parts Newcol 707SF 0.5 {Styrene 20} Cyclohexyl methacrylate 25} Methyl methacrylate 12 {N-butyl methacrylate 17} 2-Ethylhexyl acrylate 15} 2-Hydroxyethyl Methacrylate 10 〃 Acrylic acid 1 〃 Octyl mercaptan 1 〃 “TINUVIN 384-2” (Note 1) 2 〃 “TINUVIN 123” (Note 2) 1 ア ン モ ニ ウ ム Ammonium persulfate 0.4 製造 Production example 4 The obtained copolymer emulsion (C-
1) With 100 parts kept at 25 ° C., the pH of the system was adjusted to 7 with aqueous ammonia, 20 parts of methyltrimethoxysilane was added, and the mixture was stirred for about 1 hour. Thereafter, the temperature of the reaction vessel was raised to 80 ° C., and the reaction was carried out for 3 hours to obtain a polysiloxane composite copolymer emulsion (C-3).
Obtained polysiloxane composite copolymer emulsion
(C-3) has a solid content of 47% and a weight average molecular weight of 12
The average particle size was 170 nm.

Production Example 5 Production Example 3 was repeated except that phenyltrimethoxysilane was used instead of methyltrimethoxysilane.
In the same manner as in the above, a polysiloxane composite copolymer emulsion (C-4) was obtained. The obtained polysiloxane composite copolymer emulsion (C-4) had a solid content of 52%, a weight average molecular weight of 120,000 and an average particle diameter of 170 nm.

Production Example 6 The same operation as in Production Example 2 was carried out except that the amount of the pre-emulsion monomer and the amount of catalyst were changed as follows, and the solid content was 50%, the weight average molecular weight was 150,000, and the particle size was A 170 nm copolymer emulsion (C-5) was obtained.

Deionized water 85 parts Newcol 707SF 0.5 {Styrene 20} Methyl methacrylate 20 {i-butyl methacrylate 27} 2-Ethylhexyl methacrylate 22 {2-Hydroxyethyl methacrylate 10} Acrylic Acid 1 octyl mercaptan 1 Ammonium persulfate 0.6 Preparation of cross-linking agent In a four-necked flask equipped with a stirrer, thermometer, reflux tube, and nitrogen inlet tube, methoxypolyethylene ether glycol 225 having a number average molecular weight of 550 was placed. And 871 parts of 1,6-hexamethylene diisocyanate. The mixture was purged with nitrogen and reacted at 70 ° C. for 6 hours. The resulting reaction solution was applied to a thin film distillation apparatus to remove unreacted 1,6-hexamethylene diisocyanate, thereby obtaining a monoisocyanate compound having methoxypolyethylene ether glycol.

Next, 37 parts of diethanolamine was placed in a similar separate flask, and the flask was purged with nitrogen and air-cooled.
A reaction temperature of 70 parts of the monoisocyanate compound having methoxypolyethylene ether glycol obtained in
The solution was gradually dropped so as not to exceed ° C. After dropping, about 1
After stirring at 70 ° C. for a time, it was confirmed that the isocyanate group had disappeared, and an emulsifier was obtained.

In a separate flask, 42 parts of this emulsifier and 358 parts of “Takenate D170HN” (trimer of 1,6-hexamethylene diisocyanate, manufactured by Takeda Pharmaceutical Co., Ltd.) were added, and N-β was further added. -(Aminoethyl) -γ-aminopropyltrimethoxysilane (12 parts) is added and stirred at 70 ° C. for 6 hours to give water-dispersible polyisocyanate.
I got it. The isocyanate content is 17.7% and the viscosity is 80
It was 0 cps.

Preparation of Aqueous Paint for Base Adjustment Material Copolymer emulsion (A) 200 obtained in Production Example 1 above
Parts, 270 parts of calcium carbonate (specific gravity 2.7), thickener (2.5% aqueous solution of hydroxyethyl cellulose) 25
Parts, an antifoaming agent ("SN Deformer-A63", manufactured by San Nopco) and 5 parts of a dispersant ("Nopco Santo K", manufactured by San Nopco) are mixed, stirred and mixed to form a base. Paint was obtained.

To the obtained base paint, 10 parts of the crosslinking agent obtained in the above preparation example was blended, and stirred to obtain an aqueous paint for a base adjustment material. PVC of the obtained water-based paint is 50%, -1.
The elongation of the formed coating film in a 0 ° C. atmosphere is 80%.

As a water base paint for a base preparation material, “ARES HOLDER GII” (Kansai Paint Co., Ltd., water base preparation material) was prepared. The water-based paint has a PVC of 20%, -1.
The elongation percentage of the formed coating film in a 0 ° C atmosphere is 18 to 22%.

Preparation of a two-pack type water-based top coating material The following ingredients were placed in a 4-liter stainless steel container,
The mixture was stirred with a disperser for 30 minutes to obtain a pigment dispersion paste. 960 parts of tap water "Nopco Santo K" (manufactured by San Nopco, pigment dispersant) 48 "Adecanol VH420" (manufactured by Asahi Denka Co., Ltd., thickener) 16 "SN Deformer-A63" (manufactured by San Nopco, Anti-foaming agent) 32 titanium white 3520 ethanol 288 Next, in a 1-liter stainless steel container, the pigment dispersion paste and each of the copolymer emulsions obtained in Production Examples 2 to 6,
Further, other components shown in Table 1 were sequentially blended and mixed with stirring to obtain each base paint. In addition, (Note 3) in Table 1,
(Note 4) is as follows. In the obtained base paint,
The crosslinkers obtained in the above preparation examples were blended as shown in Table 1 and stirred to obtain water-based overcoat paints a to e.

Further, "Ares Aqualetan" (a water-based acrylic urethane resin-based top coating, manufactured by Kansai Paint Co., Ltd.) was prepared as the water-based top coating f. (Note 3) "Polydurex G-659": a silicone-modified acrylic resin emulsion having a weight average molecular weight of 300,000, solid content 45%, particle size 120 nm, manufactured by Asahi Kasei Corporation (Note 4) "SX-997": Nippon Synthetic Rubber Co., Ltd. Acrylic resin emulsion with a weight average molecular weight of 300,000, solid content 3
5%, particle size 60 nm

[0078]

[Table 1]

Coating Examples 1 to 4 and Comparative Examples 1 to 3 Each of the water-based paints for base adjustment materials obtained above (a crosslinking agent was mixed with the base paint and allowed to stand for 1 hour) was adjusted to a coating-appropriate viscosity with water. Thereafter, it was coated on a mortar plate (90 × 300 × 20 mm) with a sand roller so as to have an application amount of about 1.0 kg / m ^2, and dried at 20 ° C. and 75% RH for 1 day. Next, each of the aqueous topcoats obtained above was spray-coated twice on the base coat in the combinations shown in Table 2 so that the coating amount was 150 g / m ^2. It was dried on a day to obtain a painted finished plate. Each of the resulting coated plates was subjected to the following performance tests. Table 2 shows the results. (* 1) Finished appearance: The finished appearance of the coating surface of each painted plate was visually evaluated.

：: Glossy and uniformly finished without unevenness Δ: Uniformly finished without unevenness but slightly lower gloss ×: Not uniformly finished due to unevenness in suction of top coat paint, etc. (* 2) Water resistance Properties: Each coated plate was submerged in a 20 ° C. environment, and the appearance of the coating film after 7 days was visually evaluated.

：: No abnormality ×: Any one or more of peeling, cracking, blistering, swelling, remarkable discoloration, and decrease in gloss are recognized. (* 3) Stained appearance: Each painted plate was inspected in Hiratsuka-shi, Kanagawa. After monthly outdoor exposure, the degree of soiling of the coating film was visually evaluated.

：: Almost no dirt observed Δ: Slight dirt observed ×: Dirt was noticeable (* 4) Elongation rate of formed coating film: JIS using aqueous paint for base adjustment material and aqueous topcoat paint A test piece was prepared according to A6909. The elongation percentage of the multilayer coating film (dry coating film) was measured using an autograph AG2000B type tensile tester (manufactured by Shimadzu Corporation) in a -10 ° C atmosphere at a tensile speed of 200 mm /
And measured according to the following criteria.

：: Elongation rate is 20% or more Δ: １５ 15% or more and less than 20% ×: 未 満 less than 15% (* 5) Repeated hot / cold test: JIS for each coated plate
According to the hot / cold repetition test of A-6909, immersion in <20 ° C. water for 18 hours to cooling in a −20 ° C. thermostat for 3 hours to 50 hours
During the 10-cycle test, in which the heating was carried out in a thermostat at 5 ° C. for 5 hours as one cycle, the state of the coating film surface later was visually observed.

：: No abnormalities after 10 cycles Δ: Cracks and cracks occurred in 7 to 9 cycles X: Cracks and cracks occurred in 1 to 6 cycles (* 6) Weather resistance: Each painted plate was sunshine weatherometer 60-G when exposed for 2000 hours at
The gloss retention was evaluated.

：: 80% or more ×: less than 80%

[0086]

According to the present invention, a specific two-pack type water-based paint is used as a base adjustment material to form a base coating film that achieves both high elasticity and high crosslinking density even in a low-temperature environment. By coating a two-part aqueous coating composition having a monomer composition of and a copolymer emulsion containing an ultraviolet absorber and / or a light stabilizer in emulsion particles, weather resistance, durability, A coating film having extremely excellent gloss can be formed.

[0087]

[Table 2]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B05D 7/24 302 B05D 7/24 302Y 303 303E C08F 2/24 C08F 2/24 Z 2/44 2/44 B 8/42 8/42 220/00 220/00 220/18 220/18 220/26 220/26 C08G 18/62 C08G 18/62 C09D 175/04 C09D 175/04 183/04 183/04 201/06 201/06 (72) Inventor Toshihiro Hamamura 4-171-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa F-term (reference) in Kansai Paint Co., Ltd. 4D075 AE06 CA32 DC01 EA06 EA13 EA27 EB38 EB43 EC11 EC47 4J011 AA05 BB01 KA02 KA10 KB07 KB22 PA27 PA30 PA33 PA43 PA45 PB24 PC02 PC06 4J034 CA02 CA13 CB02 CB08 CC01 CC08 CD04 DA01 DB01 DC50 DG03 DG05 DG14 DP18 HA01 HA02 HA07 HA11 HB08 HC03 HC12 HC17 HC46 HC52 HC61 HC64 HC67 HC71 HC73 JA42 JA43 KA01 KB04 KC17 KD12 KE02 MA01 MA02 MA04 QA01 QA03 RA07 4J038 CD092 CG002 DG181 DG191 DG261 DL031 DL032 KA03 KA08 MA10 MA13 MA14 PB05 PC02 PC04 PC08 4J100 AB02R AB03R AB04R AC03R AC21R AE02R AG03R08 AL08 AL03 AL08 AL08 AL02 BA77R BB18R BC04P CA05 CA31 DA01 DA25 EA06 EA09 FA18 HA35 HA61 HC78 HC80 JA01

Claims (3)

[Claims] (1) A hydroxyl value of 5 to 100 mg is applied to a surface to be coated.
Base paint (I-1) containing water-dispersible resin having KOH / g, glass transition temperature of -50 to 0 ° C., weight average molecular weight of 20,000 to 400,000 and (B) pigment
A crosslinking agent (II-1) containing a compound containing at least two or more isocyanate groups in one molecule, and a crosslinking agent per 1 mol of a hydroxyl group contained in the base paint (I-1). The isocyanate group contained in (II-1) is from 0.05 to
A water-based paint mixed immediately before use so as to have a concentration of 3.0 mol, wherein the pigment has a pigment volume concentration of 2 in the formed coating film.
0 to 70%, and the elongation of the formed coating film is 2
0% or more of a two-component aqueous base conditioner is applied, and then (C) (a) 5 to 60% by weight of a polymerizable unsaturated monomer having a cycloalkyl group, and (b) hydroxyl group-containing polymerization. A monomer mixture comprising 5 to 30% by weight of a polymerizable unsaturated monomer and 10 to 90% by weight of (c) another polymerizable unsaturated monomer;
(D) a base paint containing a copolymer emulsion containing an ultraviolet absorber and / or a light stabilizer as a main component, which is obtained by emulsion polymerization of a mixture with an ultraviolet absorber and / or a light stabilizer (I- 2) a crosslinking agent (II-2) containing a compound containing at least two or more isocyanate groups in one molecule;
The isocyanate group contained in the crosslinking agent (II-2) is in the range of 0.2 to 3.0 mol per 1 mol of the hydroxyl group contained in the base paint (I-2). A paint finishing method in which a two-pack type water-based topcoat is mixed just before use. 2. The copolymer emulsion (C) is added with one or both of an alkoxysilane compound and a low molecular weight organosiloxane compound after the emulsion polymerization and subjected to a condensation reaction to form a polysiloxane composite copolymer emulsion. 2. The method according to claim 1, wherein the coating is performed. 3. A copolymer emulsion (D) having a hydroxyl group which is difficult to be fused in a dispersed state with the copolymer emulsion (C) is obtained by adding (D) to 100 parts by weight of resin solid content (C). Claims to be contained in an amount of 2 to 30 parts by weight.
The paint finishing method described in 1.