JP2002035676A - Coating finishing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating finishing method using a coating material having small organic solvent content, free from the problem about the storage stability of the coating material and capable of preventing the generation of a mixed layer of the under coating with the top coating in a multilayer coating system. SOLUTION: A colored base coating material composition containing (A) a polyorthoester prepared by the reaction of and orthoester (a), a glycol compound (b) with a polyol (c), (B) at least one kind of a hardening agent selected from an amino resin hardening agent and a polyisocyanate that may be blocked and (C) pigments selected from color pigments and bright pigments is applied, and a water based clear coating material is applied on the unhardened color base coating film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for finishing a colored base paint and a water-based clear paint on a wet-on-wet basis.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand for reduction of organic solvents in coatings due to the problems of the global environment, coating work environment and resource depletion.
Various techniques, such as aqueous conversion, are being studied. In the multilayer coating system for the outer surface of cans, similar investigations have been made for each of the colored base paint of the undercoat layer and the clear paint of the top coat layer.From the viewpoint of improving productivity, the colored base paint and the clear paint are used. Painted wet on wet,
A two-coat one-bake system for baking and curing at a time has also been studied. When applying a colored base paint and clear paint wet-on-wet, there are major problems with coating workability, such as the tendency for mixed layers of the upper and lower layers to occur, and for the baking of the upper and lower layers to occur at the same time. A method of using a solvent-based high-solid paint as a coloring base paint and an aqueous paint as a clear paint has been studied.

At present, as a paint for the outer surface of a can, a combination of a hydroxyl group-containing resin (hereinafter sometimes referred to as a polyol) such as an acrylic resin or a polyester resin and a curing agent such as an amino resin or a polyisocyanate compound is widely used. . When trying to make the above-mentioned colored base paint high solid, usually, the molecular weight of the base resin and the curing agent is reduced. However, lowering the molecular weight of the polyol, which is the base resin, causes a decrease in the physical properties of the coating film. In order to compensate for this, there is a problem in that when the curability is improved by increasing the number of hydroxyl groups, the storage property of the paint is reduced. The increased hydroxyl group increases the polarity of the polyol, so that a layer of the polyol and the water-based clear coating is easily formed, and the pigment in the colored base coating is agglomerated so that the original color of the pigment cannot be exhibited.

[0004] The main object of the present invention is to provide a multi-layer coating system in which the amount of organic solvent in the coating is small, there is no problem in the storage stability of the coating, and there is no mixing between the colored base coating and the aqueous clear coating. It is to provide a finishing method.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, by blocking the hydroxyl groups in the polyol used for the colored base coating with an orthoester, the low molecular weight of the polyol has been reduced. It has been found that the storage stability of the coating composition can be prevented from deteriorating due to the formation of a solid (high solidification), and that the mixed layer with the water-based clear coating composition can be solved, and the present invention has been completed. That is, the present invention relates to [A] (a)

[0006]

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In the formula, R ¹ is a hydrogen atom or a group having 1 to 1 carbon atoms.
Orthoesters represented by (b) α-glycol and β, wherein R ³ is the same or different and each represents an alkyl group having 1 to 4 carbon atoms.
-At least one glycol compound selected from glycols, and (c) a number average molecular weight of 90 to 50,000.
And the hydroxyl value is within a range of 20 to 1,850 mgK.
A polyorthoester obtained by reacting a polyol in the range of OH / g, [B] at least one curing agent selected from an amino resin curing agent and an optionally blocked polyisocyanate compound, and [C] A paint finishing method, which comprises applying a colored base coating composition containing a pigment selected from a coloring pigment and a bright pigment, and then applying an aqueous clear coating on the uncured colored base coating film. Is provided.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the method of the present invention will be described in more detail.

In the method of the present invention, a colored base coating composition which is a solvent type high solid coating is applied as a lower layer,
After applying an aqueous clear paint as an upper layer in a wet-on-wet manner, the above-mentioned colored base coating composition for simultaneously baking and curing both layers is a polyorthoester [A], a curing agent [B] and a pigment [ C] as an essential component.

Polyorthoester [A] Polyorthoester [A] is a reaction product of orthoester (a), glycol compound (b) and polyol (c) described below.

Orthoester (a) The orthoester (a) is represented by the following formula (1)

[0012]

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In the formula, R ¹ is a hydrogen atom or a group having 1 to 1 carbon atoms.
And R ³ is the same or different and each represents an alkyl group having 1 to 4 carbon atoms.

In the above formula (1), the alkyl group having 1 to 4 carbon atoms represented by R ¹ or R ² is linear or branched, for example, methyl, ethyl, n-propyl, isopropyl, Examples thereof include n-butyl, isobutyl, and t-butyl groups.

Specific examples of the orthoester (a) include:
For example, methyl orthoformate, ethyl orthoformate, propyl orthoformate, butyl orthoformate, methyl orthoacetate,
Examples thereof include ethyl orthoacetate, methyl orthopropionate, ethyl orthopropionate, methyl orthobutyrate, and ethyl orthobutyrate. Of these, methyl orthoformate, ethyl orthoformate, methyl orthoacetate, and methyl orthoacetate are preferred. . These can be used alone or in combination of two or more.

Glycol Compound (b) The glycol compound (b) is at least one glycol compound selected from α-glycol and β-glycol having two hydroxyl groups in one molecule.

As the α-glycol, particularly, the following formula (2)

[0018]

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Where R^Three, R^Four, R^FiveAnd R⁶Are the same or different
Are hydrogen or carbon atoms each having 1 to 24 carbon atoms.
Alkyl group, aralkyl group having 7 to 24 carbon atoms or
Nyl group or a part of these groups is replaced by oxygen atom
Represents a group consisting of ^Three, R^Four, R^FiveAnd R⁶Represented by
The total number of carbon atoms in the group is from 0 to 24, preferably from 0 to 10
And R^FourAnd R^FiveAre directly linked
Together with a carbon atom to form a cyclic structure
And the compound represented by

In the above formula (2), the alkyl group having 1 to 24 carbon atoms represented by R ³ , R ⁴ , R ⁵ and R ⁶ is linear, branched or cyclic; Ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, pentyl, hexyl, n-octyl, 2-ethylhexyl, decyl, dodecyl, octadecyl, cyclohexyl, methylcyclohexyl, cyclohexylmethyl, cyclohexylethyl and the like be able to.

In the above formula (2), the aralkyl group having 7 to 24 carbon atoms represented by R ³ , R ⁴ , R ⁵ and R ⁶ is preferably a phenyl-substituted alkyl group. Is, for example, a benzyl or phenethyl group.

In the above formula (2), a group in which a part of the alkyl group, aralkyl group or phenyl group represented by R ³ , R ⁴ , R ⁵ and R ⁶ is substituted by an oxygen atom is methoxy. Alkoxyalkyl groups such as methyl, ethoxymethyl, propoxymethyl, butoxymethyl;
Alkanoyloxyalkyl groups such as acetoxymethyl and acetoxyethyl; phenoxymethyl and phenoxyethyl groups;

R ³ , R ⁴ , R ⁵ and R ⁶ in the above formula (2) are preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

Thus, typical examples of the above α-glycol include, for example, ethylene glycol, 1,2-propylene glycol, 1,2-butylene glycol, 2,3
-Butylene glycol, 1,2-hexanediol,
Hydrolysis products of 1,2-dihydroxycyclohexane, pinacol, and long-chain alkyl monoepoxide; fatty acid monoglycerides (α-form) such as glycerin monoacetate (α-form) and glycerin monostearate (α-form); 3-ethoxypropane-1 , 2-diol, 3-phenoxypropane-1,2-diol and the like.
Of these, ethylene glycol, 1,2
-Propylene glycol, 1,2-hexanediol are preferred.

On the other hand, as the β-glycol, particularly, the following formula (3)

[0026]

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Wherein R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ and R
¹² is the same or different and each is a hydrogen atom or an alkyl group having 1 to 24 carbon atoms, an aralkyl group or a phenyl group having 7 to 24 carbon atoms, or a group in which a part of these groups is substituted with an oxygen atom And R ⁷ , R ⁸ , R ⁹ ,
The total number of carbon atoms of the groups represented by R ¹⁰ , R ¹¹ and R ¹² is in the range of 0 to 24, and R ⁷ and R ⁹ , or R ⁷ ,
As R ⁹ and R ¹¹ , a compound represented by the following formula (1), which may form a cyclic structure together with the carbon atom to which they are directly bonded, can be suitably used.

In the above formula (3), R ⁷ , R ⁸ , R ⁹ ,
1 carbon atom which can be represented by R ¹⁰ , R ¹¹ and R ¹²
As the alkyl group of the formula (2) to (24),
^{As the} alkyl group which can be represented by ³ , R ⁴ , R ⁵ and R ⁶ , those described above can be similarly mentioned.

In the above formula (3), R ⁷ , R ⁸ , R ⁹ ,
7 carbon atoms which can be represented by R ¹⁰ , R ¹¹ and R ¹²
As the aralkyl group of to 24, a phenyl-substituted alkyl group is preferable, and specifically, for example, benzyl,
And a phenethyl group.

In the above formula (3), R ⁷ , R ⁸ , R ⁹ ,
An alkyl group represented by R ¹⁰ , R ¹¹ and R ¹² ;
Examples of the group in which a part of an aralkyl group or a phenyl group is substituted with an oxygen atom include, for example, an alkoxyalkyl group such as methoxymethyl, ethoxymethyl, propoxymethyl and butoxymethyl; an alkanoyloxyalkyl group such as acetoxymethyl and acetoxyethyl Phenoxymethyl, phenoxyethyl and the like.

In the above formula (3), R ⁷ , R ⁸ , R ⁹ ,
Examples of the cyclic structure that R ¹⁰ , R ¹¹ and R ¹² can form together with the carbon atom to which they are directly bonded include a cyclohexyl group and a cyclopentyl group.

In the above formula (3), R ⁷ , R ⁸ , R ⁹ , R
^10, R ¹¹ and R ¹² are, among others, is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

Thus, typical examples of β-glycol include, for example, neopentyl glycol, 2-methyl-
1,3-propanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-butanediol,
2-ethyl-1,3-hexanediol, 2,2-diethyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-butyl-2-ethyl-1,3 -Propanediol, 2-phenoxypropane-1,3-diol, 2-methyl-2-phenylpropane-1,3-diol, 1,3-propylene glycol, 1,3-butylene glycol, dimethylolpropionic acid, Methylolbutanoic acid, 2-ethyl-1,3
-Octanediol, 1,3-dihydroxycyclohexane; and fatty acid monoglycerides (β-form) such as glycerin monoacetate (β-form) and glycerin monostearate (β-form). Of these, neopentyl glycol, 2-methyl-1,3
-Propanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-butanediol, 2-ethyl-1,3-hexanediol, 2,2-diethyl-
1,3-propanediol, 2,2,4-trimethyl-
1,3-pentanediol, 2-butyl-2-ethyl-
1,3-propanediol is preferred.

Polyol (c) The polyol as the component (c) is a compound other than the above-mentioned glycol compound (b) having two or more hydroxyl groups in one molecule.

Examples of the hydroxyl group-containing compound (c) include compounds having two hydroxyl groups other than α-glycol and β-glycol or compounds having three or more hydroxyl groups in one molecule. Is 90-50,0
00, preferably in the range of from 130 to 15,000, and has a hydroxyl value of from 20 to 1,850, preferably from 40 to 1,850.
Those within the range of 1,650 are preferred.

Compounds having two hydroxyl groups other than α-glycol and β-glycol include, for example, 1,4
-Butanediol, 1,4-dihydroxycyclohexane, 1,5-pentanediol, 1,6-hexanediol, 2,5-hexanediol, 3-methyl-1,5
-Pentanediol, 1,4-dimethylolcyclohexane, tricyclodecanedimethanol, 2,2-dimethyl-3-hydroxypropyl-2,2-dimethyl-3-
Hydroxypropionate [this corresponds to the ester of hydroxypivalic acid and neopentyl glycol], bisphenol A, bisphenol F, bis (4
-Hydroxyhexyl) -2,2-propane, bis (4
-Hydroxyhexyl) methane, 3,9-bis (1,1
-Dimethyl-2-hydroxyethyl) -2,4,8,1
0-tetraoxaspiro [5,5] undecane, diethylene glycol, triethylene glycol, polyethylene glycol of tetra or higher, dipropylene glycol,
Tripropylene glycol, tetra- or higher polypropylene glycol, copolymers having hydroxyl groups at both ends obtained by copolymerizing ethylene oxide and propylene oxide, linear polyesters having hydroxyl groups at both ends such as polycaprolactone diol, polycarbonate diol And a carboxylic acid adduct of diepoxide.

Examples of the compound having three or more hydroxyl groups include glycerin, diglycerin, triglycerin, pentaerythritol, dipentaerythritol, sorbitol, mannitol, trimethylolethane, trimethylolpropane, and ditrimethylolpropane. , Tris (2-hydroxyethyl) isocyanurate, gluconic acid and the like.

Also, various polymers containing two or more hydroxyl groups in one molecule can be suitably used. For example, polyester resins, alkyd resins, polyether resins, acrylic resins, ketone resins, phenol resins, epoxy resins Resins, epoxy ester resins, urethane resins, polyvinyl alcohol which is a saponified product of polyvinyl acetate, and natural sugars such as glucose can be used. Among them, acrylic resin, polyester resin, alkyd resin, epoxy resin and epoxy ester resin are suitable, and they can be used alone or in combination of two or more.

Production of polyorthoester [A] In producing the polyorthoester which is the component [A] in the colored base paint used in the method of the present invention, the orthoester (a), the glycol compound (b) and the polyol (c) Is not particularly limited, but the amount of the orthoester (a) is 0.01 to 10 mol per 1 equivalent of the hydroxyl group in the polyol (c),
Preferably 0.05-5 mol, more preferably 0.1 mol.
~ 2 mol, and the glycol compound (b)
Is used in a proportion within the range of 0.01 to 10 mol, preferably 0.05 to 5 mol, and more preferably 0.1 to 2 mol, from the viewpoint of easy control of molecular weight. It is.

The polyorthoester [A] can be obtained by subjecting the above three components (a), (b) and (c) to a condensation reaction. For example, the above three components are optionally subjected to a condensation reaction in the presence of an organic solvent and an acid catalyst, usually at room temperature to 250 ° C, preferably at a temperature in the range of 70 to 200 ° C for about 1 to 20 hours. Thereby, it can be suitably manufactured.

In the production of the polyorthoester [A], the alkoxyl group of the orthoester (a) undergoes an exchange reaction with the alcohol compound of the glycol compound (b) and the polyol (c). At that time, the orthoester (a) usually reacts preferentially with α-glycol or β-glycol, which is a glycol compound (b) having an adjacent hydroxyl group, to form a cyclic structure. That is, the glycol compound (b) reacts preferentially with two functional groups (alkoxyl groups) of the trifunctional orthoester (a) to cyclize. The remaining one alkoxy group of the orthoester (a) can react with the polyol (c). Thus, since the polyorthoester [A] does not involve a bridge between molecules in the production thereof, the molecular weight and the viscosity can be suppressed. On the other hand, in the absence of the glycol compound (b), the orthoester (a)
When the polyol and the polyol (c) are directly reacted, a cross-linking reaction occurs between the molecules, and the molecular weight and the viscosity of the product increase steadily. Polyorthoester [A] in the composition of the present invention
Is a compound in which an increase in molecular weight or viscosity is suppressed by reacting an orthoester (a) and a polyol (c) with the addition of a glycol compound (b).

The polyorthoester [A] of the present invention has a structure in which the hydroxyl group in the polyol (c) component is blocked with the orthoester as described above. In the case of increasing the solidification of paint by lowering the molecular weight of the polyol (c) component, it is necessary to increase the number of hydroxyl groups to increase the curability in order to compensate for the decrease in coating film performance. In addition to blocking the hydroxyl group, the decrease in the storage stability of paint can be suppressed, and the increase in polarity due to an increase in the number of hydroxyl groups can also be suppressed by blocking the hydroxyl groups. It is also possible to suppress the mixed layer of the undercoat / overcoat when coated with the above.

Curing Agent [B] At least one curing agent selected from the group consisting of the amino resin curing agent and the polyisocyanate compound which may be blocked, which is the component [B] used in the method of the present invention, is used in the composition of the present invention. The cured product can be formed by reacting an orthoester group of the polyorthoester [A] in the product with a hydroxyl group generated by hydrolysis.

Examples of the amino resin that can be used as the curing agent [B] include a methylolated amino resin obtained by reacting an amino component such as melamine, urea, benzoguanamine, acetoguanamine, steroganamin, spiroguanamine, dicyandiamide and an aldehyde with an aldehyde. No.
Examples of the aldehyde include formaldehyde, paraformaldehyde, acetaldehyde, and benzaldehyde. Further, those obtained by etherifying the methylolated melamine resin with one or more alcohols are also included in the amino resin. Examples of the alcohol used for etherification include monohydric alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, 2-ethylbutanol, and 2-ethylhexanol. . Among these, a melamine resin obtained by etherifying at least a part of the methylol group of the methylolated melamine resin with a C1-4 monohydric alcohol is preferable.

Specific examples of the melamine resin include, for example, Cymel 300, 303, 325, 327,
350, 730, 736, and 738 (all of which are manufactured by Mitsui Cytec), Melan 522, and 523
[The above are all manufactured by Hitachi Chemical Co., Ltd.], Nicaraq MS00
1, the same MX430, the same MX650 (all of which are manufactured by Sanwa Chemical Co., Ltd.), Sumimar M-55, the same M-100,
M-40S [all, all manufactured by Sumitomo Chemical Co., Ltd.], REMININ 740, 747 [all, manufactured by Monsanto Co., Ltd.]
Methyl etherified melamine resin such as Uban 20S
E, 225 (all manufactured by Mitsui Toatsu Co., Ltd.), Super Beckamine J820-60, L-117-60, L-109-65, 47-508-60, L-11
Butyl etherified melamine resins such as 8-60 and G821-60 (all of which are manufactured by Dainippon Ink and Chemicals, Ltd.); Cymel 202, 232, 266, and XV-5
14, 1130 [all of which are manufactured by Mitsui Cytec Co., Ltd.], Nicaraq MX45, MX500, MX60
Methyl ethers and butyl ethers such as 0, MS35, MS95 [all, manufactured by Sanwa Chemical Co., Ltd.], REZIMIN 753, 755 [all, manufactured by Monsanto], Sumimar M-66B [manufactured by Sumitomo Chemical Co., Ltd.] And a mixed etherified melamine resin.

Specific examples of the benzoguanamine resin include, for example, Mycoat 102, 105, and 106.
[These are all made by Mitsui Cytec Co., Ltd.], Nikarac S
B-201, SB-203, SB-301, SB
Methyl-etherified benzoguanamine resins such as -303 and SB-401 [all, manufactured by Sanwa Chemical Co.]; mixed etherified benzoguanamine resins of methyl ether and ethyl ether such as Cymel 1123 [all, manufactured by Mitsui Cytec] A mixed etherified benzoguanamine resin of methyl ether and butyl ether such as Nikarac SB-255, SB-355, BX-37, and BX-4000 [all of which are manufactured by Sanwa Chemical Co., Ltd.]; , Manufactured by Mitsui Cytec Co., Ltd.]. These melamine resins and benzoguanamine resins can be used alone or in combination of two or more.

Examples of the polyisocyanate compound usable as the curing agent [B] include an isocyanate group (NCO group)
Is not blocked (hereinafter may be abbreviated as "non-blocked polyisocyanate compound"),
And those in which the isocyanato group is blocked (hereinafter, referred to as
"May be abbreviated as" blocked polyisocyanate compound ").

Examples of the non-blocked polyisocyanate compound include aliphatic diisocyanates such as lysine diisocyanate, hexamethylene diisocyanate and trimethylhexane diisocyanate; hydrogenated xylylene diisocyanate, isophorone diisocyanate, methylcyclohexane-2,4 (or 6)-
Cycloaliphatic diisocyanates such as diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate) and 1,3- (isocyanatomethyl) cyclohexane; aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate and diphenylmethane diisocyanate An organic polyisocyanate itself such as a trivalent or higher polyisocyanate such as lysine triisocyanate, or an adduct of each of these organic polyisocyanates with a polyhydric alcohol, a low molecular weight polyester resin or water; Examples of such a cyclized polymer of each organic diisocyanate (for example, isocyanurate), a biuret-type adduct, and the like.

The blocked polyisocyanate compound is
The non-blocked polyisocyanate compound is obtained by blocking an isocyanato group with a blocking agent. Examples of the blocking agent include phenols such as phenol, cresol and xylenol; ε-caprolactam; lactams such as δ-valerolactam, γ-butyrolactam, β-propiolactam; methanol, ethanol, n- or i-propyl. Alcohol, n
Alcohols such as-, i- or t-butyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, benzyl alcohol; formamidoxime; Oximes such as acetoaldoxime, acetoxime, methyl ethyl ketoxime, diacetyl monooxime, benzophenone oxime, and cyclohexane oxime; and active methylene systems such as dimethyl malonate, diethyl malonate, ethyl acetoacetate, methyl acetoacetate, and acetylacetone. . By mixing the non-blocked polyisocyanate with the blocking agent, the isocyanate group of the polyisocyanate can be easily blocked.

These polyisocyanate compounds can be used alone or in combination of two or more.

Pigment [C] The pigmented base coating composition of the present invention contains pigments selected from general coloring pigments and bright pigments.

Examples of the above color pigments include white pigments such as titanium oxide, zinc white, lead white, basic lead sulfate, lead sulfate, lithopone, zinc sulfide, and antimony white; carbon black;
Black pigments such as acetylene black, lamp black, bone black, graphite, iron black, and aniline black; yellow pigments such as naphthol yellow S, Hansa yellow, pigment yellow L, benzidine yellow, and permanent yellow; chrome orange, chrome vermillion, and permanent orange Brown pigments such as iron oxide and amber; red pigments such as red iron red, permanent red and quinacridone red pigments; purple pigments such as cobalt purple, fast violet and methyl violet lakes, ultramarine blue, navy blue and cobalt Blue pigments such as blue, phthalocyanine blue and indigo; and green pigments such as chrome green, pigment green B and phthalocyanine green.

Examples of the glitter pigment include aluminum powder, bronze powder, copper powder, tin powder, lead powder, zinc powder, iron phosphide, glitter mica powder coated with a metal compound, mica-like iron oxide, and the like. Is mentioned. Aluminum powder used mainly has an average particle diameter of 7
It is preferably about 30 μm, and the surface may be untreated or may have been subjected to a surface treatment such as an oleic acid treatment, a stearic acid treatment, or a resin coating treatment. Also,
The aluminum powder may be either a non-leafing type or a leafing type, and a colored aluminum powder having a colored surface may also be used.

In addition to the above-mentioned coloring pigments and glitter pigments,
Inorganic fine particles can be used as necessary for improving the coating workability and the like. As the type of the inorganic fine particles, for example, silica fine particles, barium sulfate, calcium carbonate,
Examples include talc, mica, and clay.

The hydroxyl group-containing polymer [D] The top coat used in the method of the present invention contains the polyorthoester [A], the curing agent [B] and the pigments [C] as essential components. Thus, a hydroxyl group-containing polymer [D] can be contained.

The hydroxyl group-containing polymer [D] has a hydroxyl value of 3 to 300 mgKOH / g, preferably 5 to 2 mgKOH / g.
00 mg KOH / g and a number average molecular weight of 1,000
0 to 50,000, preferably 2,000 to 20,000
Those in the range of 0 are suitable. Examples of the resin type of the hydroxyl group-containing polymer [D] include acrylic resin, silicone acrylic resin, polyester resin, alkyd resin,
Silicone polyester resin, epoxy resin, epoxy ester resin, fluorine resin and the like can be mentioned. Among them, acrylic resin, polyester resin, alkyd resin, epoxy resin, epoxy ester resin can be preferably used, and It is also possible to use a combination of the above resins.

In the coating composition used in the method of the present invention, the proportions of the polyorthoester [A], the curing agent [B], the pigments [C] and the hydroxyl group-containing polymer [D] are not particularly limited. Although it is not done, [A],
Usually, based on 100 parts by weight of the total solid content of the components [B] and [D], it is generally appropriate that the solid content of each component is within the following range. [A] component: 20 to 95 parts by weight, preferably 40 to 90 parts by weight
Parts by weight, [B] component: 5 to 60 parts by weight, preferably 10 to 40 parts by weight, [C] component: 5 to 200 parts by weight, preferably 20 to 14 parts by weight
0 parts by weight. [D] Component: 0 to 75 parts by weight, preferably 0 to 50 parts by weight.

The coating composition used in the method of the present invention contains the above components [A], [B], [C] and, if necessary, the component [D]. A catalyst, organic resin fine particles, an organic solvent, a curing catalyst, an ultraviolet absorber, a coating surface adjusting agent, an antioxidant, a fluidity adjusting agent, a wax and the like can be appropriately contained.

The acid catalyst is a catalyst for promoting a reaction of deblocking an orthoester group to regenerate a hydroxyl group, and is not particularly limited.
Sulfuric acid, nitric acid; methanesulfonic acid, ethanesulfonic acid, paratoluenesulfonic acid, dodecylbenzenesulfonic acid,
Sulfonic acid compounds such as dinonylnaphthalenesulfonic acid and dinonylnaphthalenedisulfonic acid; neutralized products of the above sulfonic acid compounds with bases such as amines; the above sulfonic acid compound and n-propanol, n-butanol, n-hexanol, n -Octanol, isopropanol, 2
-Butanol, 2-hexanol, 2-octanol,
No. 1 such as cyclohexanol and tert-butanol
Esterified products with primary, secondary or tertiary alcohols;
Β-hydroxyalkylsulfonic acid esters obtained by reacting the above sulfonic acid compound with an oxirane group-containing compound such as glycidyl acetate or butyl glycidyl ether; formic acid, acetic acid, propionic acid, butyric acid, 2-ethylhexanoic acid, octanoic acid Carboxylic acids such as monobutyl phosphate, dibutyl phosphate, monoisopropyl phosphate,
Diisopropyl phosphate, monooctyl phosphate, dioctyl phosphate, monodecyl phosphate, didecyl phosphate, metaphosphoric acid, orthophosphoric acid, pyrophosphoric acid, trimethyl phosphate,
Organic phosphoric acid compounds such as triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate, tris-chloroethyl phosphate, triphenyl phosphate and tricresyl phosphate; and Lewis acids.

The organic resin fine particles are adsorbed on the surface of an aluminum pigment or the like and have the effect of improving the surface to improve coating workability, and are added as necessary.
The average particle diameter of the organic resin fine particles is 1 nm to 1 μm,
Preferably, about 50 to 500 nm is suitable. Examples of resin species of the organic resin fine particles include polyethylene, polypropylene, polytetrafluoroethylene; nylon such as nylon 11 and nylon 12; modified polyethylene such as carboxylic acid-modified polyethylene; modified polypropylene such as maleated polypropylene; silicone rubber; acrylic resin,
Examples include urethane resins and phenol resins. Among these, acrylic resins are preferred, and among them, in the presence of a reactive emulsifier having a polymerizable unsaturated group such as an allyl group, a water-soluble polymerization initiator such as a water-soluble azoamide compound is used as a polymerization initiator. Then, an internal part obtained by emulsion polymerization of a polymerizable unsaturated monomer component containing a polyfunctional monomer such as divinylbenzene or 1,6-hexanediol di (methacrylate) containing two or more polymerizable unsaturated groups. Crosslinked organic resin microparticles are preferred.

As the above-mentioned organic solvent used in the method of the present invention, those which can dissolve or disperse each component in the coating material can be used. For example, heptane, toluene, xylene,
Hydrocarbon solvents such as octane and mineral spirit; ester solvents such as ethyl acetate, n-butyl acetate, isobutyl acetate, ethylene glycol monomethyl ether acetate and diethylene glycol monobutyl ether acetate; methyl solvents such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone and cyclohexanone Ketone solvents: methanol, ethanol, isopropanol,
alcohol-based solvents such as n-butanol, sec-butanol, isobutanol; ether-based solvents such as n-butyl ether, dioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether; swazol 310, swazol 1000, swazol 1500
(These are all made by Cosmo Oil Co., Ltd.), SHELLSOL
A (Shellsol A, manufactured by Shell Chemical Co., Ltd.) and the like. These organic solvents can be used alone or in combination of two or more.

The above curing catalyst, which is blended as required,
It promotes the curing reaction of the composition of the present invention.

When the curing agent [B] is an amino resin such as a melamine resin or a benzoguanamine resin, particularly when the curing agent [B] is a low molecular weight methyl etherified or mixed etherified amino resin of methyl ether and butyl ether,
As the curing catalyst, a phosphoric acid compound, a sulfonic acid compound, or a neutralized amine thereof is suitably used. Representative examples of the sulfonic acid compound include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, and dinonylnaphthalenedisulfonic acid. The amine in the amine neutralized product may be any of a primary amine, a secondary amine, and a tertiary amine.

When the curing agent [B] is a blocked polyisocyanate compound, a curing catalyst which promotes the dissociation of the blocking agent of the blocked polyisocyanate compound as the curing agent is suitable. For example, tin octylate, dibutyltin di (2-ethylhexanoate), dioctyltin di (2-ethylhexanoate), dioctyltin diacetate, dibutyltin dilaurate, dibutyltin oxide, dioctyltin oxide, 2-ethyl An organic metal catalyst such as lead hexanoate may be used.

Water-based clear paint As the clear paint applied on the coating film coated with the colored base coating composition of the present invention, a known water-based clear paint can be used. Examples of the resin type of the aqueous clear paint include, for example, an acrylic resin, a silicone acrylic resin, a polyester resin, a silicone polyester resin, an acryl-modified epoxy resin, and a polyester-modified epoxy resin as a base resin. Resin, polyisocyanate compound,
Epoxy group-containing compounds and the like can be mentioned, and the form of the resin may be either a water-dispersed type or a water-soluble type. The top clear paint may be a color clear paint. Further, if necessary, an organic solvent, a curing catalyst, an ultraviolet absorber, a coating surface adjusting agent, an antioxidant, a fluidity adjusting agent, a wax and the like can be appropriately contained.

The amount of the organic solvent (including the neutralized amine) contained in the aqueous clear paint is preferably 30% by weight or less in the paint.

Coating Finishing Method The coating finishing method of the present invention comprises coating the above-mentioned colored base coating composition of the present invention on a base material, and then applying an aqueous clear coating composition on the uncured colored base coating film by wet-on-coating. It is to be painted wet.

The base material to be coated in the coating and finishing method of the present invention includes, for example, tin, aluminum, tin-free steel, iron, zinc, copper, galvanized steel sheet,
Metal sheets such as alloy-plated steel sheets of zinc and other metals; Chemically treated metal sheets obtained by subjecting these metals to phosphate treatment or chromate treatment; Polyesters such as polyethylene terephthalate to these metal sheets or chemically treated metal sheets Resin, polyolefin resin such as polyethylene and polypropylene,
Resin film-laminated metal plates formed by laminating resin films such as polyamide resin, epoxy resin, and polyvinyl chloride; molded products such as cans formed by processing these metal plates, chemical conversion-treated metal plates or resin film-laminated metal plates; Wood, plastics, concrete and the like can be mentioned.

As the coated surface of the above-mentioned base material, the surface of a metal plate, a chemical conversion-treated metal plate or a resin film laminated metal plate which is formed into a can after coating and becomes an outer surface of the can is particularly suitable.

The colored base coating composition in the method of the present invention is applied on a substrate by a method such as roll coater coating, spray coating, brush coating, bar coating, roller coating, offset printing, silk screen printing and the like. Can be. The coating film thickness may be appropriately selected within a range in which a good coating film appearance can be obtained, and is usually in a range of about 1 to 20 μm as a dry coating film thickness. A range of 1 to 8 μm is preferred.

On the other hand, the water-based clear paint applied on a wet-on-wet basis after the colored base paint composition has been applied must be applied so as not to disturb the lower colored base layer as much as possible. Suitable methods include coater coating, spray coating, die coater coating, and curtain flow coating. The coating film thickness may be appropriately selected within a range in which a good coating film appearance can be obtained.
A range where the dry coating thickness is about 1 to 20 μm is suitable.

The conditions for baking the coating film are not particularly limited as long as the coating film is cured, but are usually not limited.
Suitably, it is in the range of from 150 to 300 ° C. for from 10 seconds to 20 minutes.

[0073]

The present invention will be described more specifically below with reference to examples and comparative examples. In the following, “parts” and “%” mean “parts by weight” and “% by weight”, respectively.

Synthesis of Polyol Synthesis Example 1 Production of Polyester Solution A reactor equipped with a stirrer, a cooler, a temperature controller, a water separator, a rectification tower, a nitrogen inlet tube and a solvent recovery device was charged with 1,6.
161 parts of hexanediol, 351 parts of 1,4-dimethylolcyclohexane, 146 parts of trimethylolpropane
Part, adipic acid 114 parts, hexahydrophthalic anhydride 3
After the reaction vessel was charged with 00 parts and 243 parts of isophthalic acid, and the atmosphere in the reaction vessel was replaced with nitrogen, the temperature was raised to 170 ° C to 230 ° C.
The temperature was raised to a constant rate over 3 hours while removing condensed water over 3 hours, and then maintained at 230 ° C. for 1 hour. Thereafter, 50 parts of xylene was added, the reaction was further continued for 3 hours while removing condensed water by a water separator while maintaining the temperature at 230 ° C., and then cooled, and 464 parts of xylene were added to obtain a non-volatile content of about 69%. A polyester solution (R-1) having Gardner viscosity (20 ° C.) X was obtained. The obtained resin (solid content) has a resin acid value of 6.5 mgKOH / g and a hydroxyl value of 120 mgKOH.
/ G, number average molecular weight 1,800, weight average molecular weight 5,2
00.

Synthesis Example 2 Production of Acrylic Resin Solution A reactor equipped with a stirrer, a cooler, a temperature controller, a nitrogen inlet tube and a dropping funnel was charged with 983 parts of xylene and 240 parts of 3-methoxybutyl acetate. The inside was replaced with nitrogen and heated to 135 ° C. In this, styrene 600 parts, isobutyl methacrylate 63
6 parts, 552 parts of 2-ethylhexyl acrylate, 2-
A mixture consisting of 612 parts of hydroxyethyl methacrylate and 192 parts of azobisisobutyronitrile was added dropwise over 4 hours. After completion of the dropwise addition, the mixture was aged at 135 ° C. for 30 minutes, and then a mixed solution consisting of 168 parts of xylene and 12 parts of azobisisobutyronitrile was added dropwise over 1 hour. About 63%, Gardner viscosity (20 ° C) U + acrylic resin solution (R-
2) was obtained. The obtained resin (solid content) has a hydroxyl value of 11
It was 0 mgKOH / g, number average molecular weight was 1,900, and weight average molecular weight was 4,300.

Synthesis of Organic Resin Fine Particles Synthesis Example 3 1 equipped with a stirrer, thermometer, cooling pipe and heating mantle
In a liter flask, 3536.5 parts of deionized water and an aqueous solution of “eleminol JS-2” (manufactured by Sanyo Chemical Industries, Inc., a sulfosuccinic acid-based allyl group-containing anionic reactive emulsifier,
(Solid content: 39%), and the mixture was heated to 90 ° C. while stirring. Among them, “VA-086” (Wako Pure Chemical Industries, Ltd., water-soluble azoamide polymerization initiator, 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) -propionamide]) 12.5 20% of an aqueous solution of which parts were dissolved in 500 parts of deionized water was added. After 15 minutes while maintaining the inside of the flask at 90 ° C., 50 parts of a mixture of 470 parts of styrene, 470 parts of n-butyl acrylate and 60 parts of 1,6-hexanediol diacrylate were used.
After stirring for 30 minutes, dropping of the remaining total amount of the monomer mixture (950 parts) and the remaining total amount of the aqueous solution of “VA-086” was started. The dropping of the monomer mixture was performed over 3 hours, and the dropping of the aqueous solution of “VA-086” was performed over 3.5 hours. After the dropping of the aqueous solution of “VA-086” was completed, the mixture was heated for 30 minutes and maintained at 90 ° C., cooled to room temperature, taken out using a filter cloth, and dispersed in an aqueous gelled organic resin fine particle aqueous solution having a solid content of 20%. I got The particle diameter of the organic resin fine particles in the aqueous dispersion was about 69 nm as measured by Nanoizer N-4 manufactured by Coulter Corporation. This aqueous dispersion was dried in a 60 ° C. electric hot air dryer on a stainless steel vat to obtain organic resin fine particles [1] as solid resin powder.

[0077] Preparation Example polyorthoesters 1 stirrer, condenser, reactor having a temperature control device and a solvent recovery apparatus, 424 parts of methyl orthoacetate, 2-butyl-2-ethyl-1,3-propane 640 parts of a diol, 136 parts of pentaerythritol and 4 parts of a 90% formic acid aqueous solution were charged, and the mixture was maintained at about 85 ° C. for 1 hour while distilling off methanol produced by the alcohol exchange reaction. afterwards,
The temperature was raised to 190 ° C. over 2 hours to recover 365 parts of methanol to obtain a colorless and transparent liquid polyorthoester A. The resulting polyorthoester A has a solid content of 100
%, Gardner viscosity X ⁺ and weight average molecular weight 1540.

Production Example 2 106 parts of methyl orthoformate, 160 parts of 2-butyl-2-ethyl-1,3-propanediol and 160 parts of polyester were placed in a reactor equipped with a stirrer, a cooler, a temperature controller and a solvent recovery unit. 968 parts of solution (R-1) (solid content: 668
Was maintained at about 85 ° C. for 1 hour while distilling off methanol produced by the alcohol exchange reaction. Thereafter, the temperature was raised to 190 ° C. over 2 hours to recover 91 parts of methanol, and the colorless and transparent liquid polyorthoester B was recovered.
I got The obtained polyorthoester B has a solid content of 74.
%, Gardner viscosity Z, and weight average molecular weight 6950.

Production Example 3 360 parts of methyl orthoacetate, 312 parts of neopentyl glycol and Plaxel 305 (polycaprolactone polyol manufactured by Daicel Chemical Industries, Ltd.) ) 550 parts and 3 parts of a 90% formic acid aqueous solution were charged and maintained at about 85 ° C. for 1 hour while distilling off methanol produced by the alcohol exchange reaction. Thereafter, the temperature was raised to 190 ° C. over 2 hours to recover 267 parts of methanol to obtain a colorless, transparent and liquid polyorthoester C. The obtained polyorthoester C had a solid content of 100%, a Gardner viscosity of S, and a weight average molecular weight of 1640.

Production Example 4 A reactor equipped with a stirrer, a cooler, a temperature controller and a solvent recovery device was charged with 120 parts of methyl orthoacetate, 160 parts of 2-butyl-2-ethyl-1,3-propanediol, 1349 parts of the solution (R-2) (850 parts of solid content) and 2 parts of a 90% formic acid aqueous solution were charged, and the mixture was heated to about 85 ° C. while distilling off methanol produced by the alcohol exchange reaction.
Hold for hours. Thereafter, the temperature was raised to 190 ° C. over 2 hours to recover 92 parts of methanol to obtain a colorless, transparent and liquid polyorthoester D. The obtained polyorthoester D had a solid content of 68%, a Gardner viscosity of UV, and a weight average molecular weight of 5620.

Production Example 5 of Aqueous Clear Paint Production Example 30 30 parts of ethylene glycol monobutyl ether was charged into a reactor equipped with a stirrer, a cooler, a temperature controller and a nitrogen gas injection tube, and heated to 120 ° C. While maintaining the same temperature, 30 parts of styrene, 20 parts of methyl methacrylate, 2-ethylhexyl methacrylate 1
8 parts, 18 parts of Praxel FM3 (manufactured by Daicel Chemical Industries, lactone-modified methacrylate, solid content 100%), 2 parts
A mixture of 10 parts of hydroxyethyl methacrylate, 4 parts of acrylic acid and 10 parts of azobisisobutyronitrile as a polymerization initiator was added dropwise over 3 hours. Further, after aging at the same temperature for 1 hour, a mixed solution of 1 part of azobisisobutyronitrile and 10 parts of ethylene glycol monobutyl ether was added dropwise over 1 hour, and aged at the same temperature for 3 hours.
An acrylic resin solution having a solid content of 71% was obtained.

To 39 parts of the acrylic resin solution obtained above, 15 parts of Cymel 325 (manufactured by Mitsui Cytec, methyl etherified melamine resin, solid content: 80%), 9 parts of ethylene glycol monobutyl ether, N, N-dimethylamino 1.4 parts of ethanol was added and mixed with stirring. Next, Nacure 4167 (Nailure 4167, manufactured by King Industries, a phosphoric acid-based catalyst, active ingredient 2)
(5%) 3.2 parts (active ingredient 0.8 part) was added and uniformly stirred and mixed, and then deionized water was gradually charged with stirring to obtain an aqueous clear coating material having a solid content of 40%. The organic solvent content of the resulting water-based clear paint was 25%.

Preparation of Colored Base Coating Composition Preparation Example 1 Nikalac MX-45 (manufactured by Sanwa Chemical Co., methyl / butyl mixed etherified melamine resin, solid content 100%) was added to 50 parts of the polyorthoester A obtained in Preparation Example 1. An appropriate amount of an organic solvent mixed solution a having a ratio of 50 parts and Swazole # 1500 (manufactured by Cosmo Oil Co., Ltd., high-boiling aromatic hydrocarbon solvent) / cyclohexanone / 3-methoxybutyl acetate = 40/30/30 for viscosity adjustment Mix and mix well, A
5 parts of EROSIL200 (Aerosil 200, manufactured by Nippon Aerosil Co., Ltd., finely divided silica) and 5 parts of the organic resin fine particles [1] of Synthesis Example 3 were added and mixed with stirring until the liquid became uniform. Next, aluminum paste 5640NS (Toyo Aluminum Co., Ltd., non-leafing aluminum, solid content 80 parts) 1
Add 14 parts, stir and mix.
43 (Nailure 5543, manufactured by King Industries, sulfonate-based acid catalyst solution, active ingredient 25%) 4
After adding 1 part (1 part of the active ingredient), the above-mentioned organic solvent mixed solution a was appropriately added and diluted, and the viscosity was adjusted to 2 Pa · s (25 ° C.) to obtain a coating composition. The solids content of this coating composition was 68%.

Preparation Examples 2 to 20 Preparation of each coating composition was carried out in the same manner as in Preparation Example 1 except that the composition was changed as shown in Tables 1 and 2 below. In Preparation Example 12, polyorthoester C was used. In Preparation Example 20, Praxel 305 (manufactured by Daicel Chemical Industries, Ltd., polycaprolactone polyol, solid content: 100%) was used as an IR pigment which was a red pigment.
GAZIN Red A2BN (Irgazine Red
A2BN, manufactured by Ciba Specialty Chemicals)
Was subjected to sand mill dispersion and used. Also, the Elitel UE-3200 of the sixth and ninth embodiments and the AR of the eighth embodiment
About UFON UH-2010, what was previously diluted with the above-mentioned organic solvent mixed solution a until the solid content became 30% was used. Here, Preparation Examples 13 to 20 were produced for comparison.

Storage Stability of Paint Each paint obtained in Preparation Examples 1 to 20 was subjected to the following pot life test. The test results are shown in Tables 1 and 2 below.

Pot life: 100 cc of each coating composition
, Sealed and left in a dark place at 30 ° C. for 24 hours, and the fluidity after storage was evaluated based on the following criteria.

：: Has fluidity, X: Has no fluidity.

Preparation of Test Coated Plates Examples 1 to 12 and Comparative Examples 1 to 8 Each of the colored base coating compositions obtained in the above preparation examples was prepared to a thickness of 0.1%.
A bar coater was applied to a PET steel sheet obtained by thermocompression bonding a homo-PET (polyethylene terephthalate) sheet having a thickness of 12 μm to a 20-mm tin-free steel sheet so that the dry film thickness became 3 μm. The obtained water-based clear paint was roll-coated so that the dry film thickness became 5 μm, passed through a tunnel-type conveyor oven at an ambient temperature of 210 ° C. for 2 minutes, and baked to obtain a test coated plate. The obtained test coated plate was tested according to the following test method.

The test results are shown in Tables 1 and 2 below.

Test method : Pigment aggregation state: The pigment aggregation state of the test coated plate was visually evaluated based on the following criteria.

：: No pigment aggregation is observed, and the original color feeling of the pigment is exhibited. Δ: Slight pigment aggregation is observed. X: Remarkable pigment aggregation is observed, and the pigment has no original color feeling.

DuPont impact workability: JIS K5400
According to the Dupont-type impact resistance test specified in the above, the point diameter of the point of impact is 1/2 inch, the drop weight is 500 g, and the drop distance is 3
Under the condition of 0 cm, impact processing was performed from the back side of the coating surface of the test coated plate. The state of cracking of the coating film after the test was visually evaluated based on the following criteria.

：: no cracking of the coating film was observed, Δ: slight cracking of the coating film was observed, ×: cracking of the coating film was remarkable.

[0094]

[Table 1]

[0095]

[Table 2]

The values of the formulations in Tables 1 and 2 indicate the amount of the solid content or the amount of the active ingredient, and the notes have the following meanings, respectively. (Note 1) Cymel 1123: Mitsui Cytec Co., Ltd., methyl / ethyl mixed etherified benzoguanamine resin, solid content 100% (Note 2) Duranate TPA-100: Asahi Kasei Corporation, hexamethylene diisocyanate polyisocyanate compound, solid content 100 % (Note 3) Duranate TPA-B80X: hexamethylene diisocyanate block polyisocyanate compound, manufactured by Asahi Kasei Corporation, solid content 80% (Note 4) Alpaste 5640NS: manufactured by Toyo Aluminum, non-leafing aluminum paste, average particle size 14
μm, solid content 70% (Note 5) Friend Color 500SI: Showa Aluminum Powder Co., Ltd., colored aluminum pigment, average particle size 17 μm, solid content 54% (Note 6) Iriogin 302 (Iriodin 302):
Gold colored pearl pigment, manufactured by Merck Japan Ltd., particle size 5 to 25 μm, solid content 100% (Note 7) Elitel UE-3200: Unitika, polyester resin, average molecular weight 16,000, hydroxyl value 6, solid content 100 (Note 8) Takerac U-502: manufactured by Takeda Pharmaceutical Co., Ltd., alkyd resin, average molecular weight 2,340, hydroxyl value 52, solid content 100% (Note 9) ARUFON UH-2010 (Alphon U)
H-2010): Toa Gosei Co., Ltd., acrylic resin, average molecular weight 10,000, hydroxyl value 90, solid content 100%

[0097]

The paint finishing method of the present invention comprises the steps of:
A high-solid solvent type colored base coating composition is applied, and then an aqueous clear coating is applied wet-on-wet. The hydroxyl group in the polyol resin used for the colored base coating is blocked by orthoester. As a result, it is possible to form a comprehensive coating film having an excellent appearance without a decrease in the storage stability of the coating due to high solidification and without mixing even when the aqueous clear coating is applied wet-on-wet. .

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 175/08 C09D 175/08 (72) Inventor Yoshizumi Matsuno 4-171-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Prefecture Kansai Paint Co., Ltd. (72) Inventor Hirohiko Aida 4-17-1, Higashiyawata, Hiratsuka-shi, Kanagawa F Kansai Paint Co., Ltd. F-term (reference) 4D075 AE10 CA47 DB01 DC42 EA06 EA43 EB22 EB33 EB35 EB52 EC11 EC37 4J038 CD092 CG002 DA142 DA162 DA172 DA192 DB002 DD002 DD122 DG001 DG051 DG111 DG131 DG151 DG161 DG191 DG271 DG301 GA02 GA03 HA026 HA036 HA216 HA286 HA356 HA376 HA446 HA536 HA546 JC29 JC39 KA03 KA08 MA07 MA10 NA26 NA27 PA15 PC02 PC08

Claims (10)

[Claims] [A] (a) (a) The following formula (1) In the formula, R ¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and three R ^{2 s} are the same or different and each represent an alkyl group having 1 to 4 carbon atoms. , (B) at least one glycol compound selected from α-glycol and β-glycol, and (c) a number average molecular weight in the range of 90 to 50,000 and a hydroxyl value of 20 to 1,850 mg KOH / g. At least one selected from the group consisting of: a polyorthoester obtained by reacting a polyol within the range of (B), [B] an amino resin curing agent, and a polyisocyanate compound which may be blocked.
A coloring base coating composition containing a kind of curing agent, and [C] a pigment selected from a coloring pigment and a glittering pigment, and then coating an aqueous clear coating on the uncured coloring base coating film. A paint finishing method characterized by that. 2. The method according to claim 1, wherein the orthoester (a) is at least one compound selected from methyl orthoformate, ethyl orthoformate, methyl orthoacetate and ethyl orthoacetate. . 3. The method according to claim 1, wherein the polyol (c) is at least one polyol resin selected from an acrylic resin, a polyester resin, an alkyd resin, an epoxy resin and an epoxy ester resin. 4. The method according to claim 1, wherein the hydroxyl group in the polyol (c) is blocked by a 5- or 6-membered orthoester composed of the orthoester (a) and the glycol compound (b). The coating finishing method according to claim 1. 5. The colored base coating composition further comprises 3 to 3
A hydroxyl value in the range of 00 mg KOH / g and 1,000
The coating finishing method according to any one of claims 1 to 4, further comprising a hydroxyl group-containing polymer [D] having a number average molecular weight in the range of from 50,000 to 50,000. 6. The method according to claim 5, wherein the hydroxyl group-containing polymer [D] is at least one polymer selected from acrylic resins, polyester resins, alkyd resins, epoxy resins and epoxy ester resins. 7. The compounding ratio of the polyorthoester [A], the curing agent [B], the pigments [C] and the hydroxyl group-containing polymer [D] in the colored base coating composition is [A], [B].
And (D) based on a total of 100 parts by weight of the solid content of the component,
The component (A) is 20 to 95 parts by weight, and the component (B) is 5 to 60 parts by weight.
The coating finishing method according to any one of claims 1 to 6, wherein the component (C) is in a range of 5 to 200 parts by weight, and the component (D) is in a range of 0 to 75 parts by weight. 8. The method according to claim 1, wherein the colored base coating composition further contains an acid catalyst. 9. The method according to claim 1, wherein the colored base coating composition further contains organic resin fine particles. 10. The method according to claim 1, wherein the aqueous clear paint has an organic solvent content of 30% by weight or less in the paint.