JPH08318211A - Coating method for top coat - Google Patents

Abstract

PURPOSE: To contrive enhancement of adhesivity to an undercoating paint film and blistering resistance by applying both one package base coating paint which contains an oxazoline group-containing vinyl-based polymer as an essential component and a crosslinking type top coating clear paint and hardening the paints. CONSTITUTION: A coating face is formed by applying one package base coating paint and furthermore a crosslinking type clear paint is applied to the coating face and hardened. In this case, as the one package base coating paint, an oxazoline group-containing vinyl-based polymer is used as an essential component. As the crosslinking type clear paint, resin composition obtained by blending a polyisocyanate compound with a hydroxyl group-containing resin is used as a main component. Further, a cellulose derivative such as cellulose acetate or cellulose butyrate may be added to the base coating component. An acrylic resin containing a hydroxyl group, a fluororesin containing a hydroxyl group or a polyester resin containing a hydroxyl group are used as the hydroxyl group-containing resin. A paint film obtained herein is used for a top coat to repair an automobile because adhesivity and water resistance, etc., are especially excellent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel and useful top coating method. More specifically, the present invention applies a one-pack type base coat paint containing an oxazoline group-containing vinyl polymer as an essential base resin component, and then a hydroxyl group-containing resin, and a resin composition comprising a polyisocyanate compound. It is extremely practical that it can be used for applications such as automobile repair topcoat, which can form a coating film with excellent adhesion and water resistance, especially by coating and crosslinking the crosslinkable topcoat clear paint as the main component. High-quality top coating method.

[0002]

2. Description of the Related Art In automobile repair coating, a so-called wet-on-wet method is adopted as a top coating method.

That is, various cross-linking resins such as hydroxyl group-containing acrylic resin and hydroxyl group-containing polyester resin, and a polyisocyanate compound are the main components, and a metal powder and / or a coloring pigment are mixed therein. Immediately after applying the two-component base coat paint, as a topcoat, various crosslinkable resins such as hydroxyl group-containing acrylic resin, hydroxyl group-containing fluororesin, hydroxyl group-containing polyester resin or hydroxyl group-containing alkyd resin, and polyisocyanate compound It is a clearing method, that is, a coating method in which a two-component clear paint containing as a main component is applied and simultaneously cured.

The purpose of such a clear finish is, among other things, various coating film properties such as durability and chemical resistance,
That is to improve the appearance of the coating film.

However, since the base coat paint used in such a top coating method is a two-pack type, its handling is complicated and complicated, and in addition, the stability of the paint is poor. .

Further, the appearance of the coating film is not preferable because there are problems such as metallic unevenness (metallic unevenness) and deterioration of gloss. As one of the means for solving this problem, a method of using a so-called one-pack base coat paint in a form in which a cellulose acetate butyrate and a melamine resin are mixed with a hydroxyl group-containing acrylic resin or a hydroxyl group-containing polyester resin, etc. Although this coating method is also known, the coating stability and the appearance of the coating film are improved, but they have a drawback that they are inferior in adhesion to a base coating film and blister resistance.

[0007]

However, the present inventors have solved the drawbacks of the conventional techniques as described above, and further improved the adhesion to the underlying coating and the blister resistance. In addition, in order to find a very useful topcoating method that is excellent in the appearance of the coating film, we have earnestly started research.

[0008] Therefore, the problem to be solved by the present invention is an extremely practical topcoating method which is excellent in adhesion to a base coat and blister resistance, and is also excellent in appearance of the coat. Is to provide.

[0009]

Means for Solving the Problems Accordingly, the present inventors have:
In accordance with the problems to be solved by the invention as described above, as a result of extensive and intensive studies, it comprises a specific oxazoline group-containing vinyl polymer as an essential component.
It consists of coating a specific one-part base coat paint and a specific cross-linking clear top coat by a wet-on-wet method and curing it. Especially, adhesion to the underlying coating and blister resistance And so on,
In addition, the present invention has been completed here by finding an extremely practical topcoating method which is particularly excellent in the appearance of the coating film.

That is, basically, as one of the inventions, the present invention applies a one-pack type base coat paint (I) containing a metal powder and / or a coloring pigment onto an article to be coated,
Then, in the top coat coating method of coating the cross-linked clear coating (II) on the coated surface to cross-link,

While the oxazoline group-containing vinyl polymer (A) is used as an essential component in the one-pack type base coat paint (I), the hydroxyl group-containing resin (B) is used as the cross-linkable clear paint (II). ), A resin composition obtained by blending the polyisocyanate compound (C) as a main component is used to form a desired coating film. There

Secondly, as the above-mentioned one-pack type base coat paint (I), a resin composition obtained by mixing a cellulose derivative (D) with an oxazoline group-containing vinyl polymer (A) is used as a main component. On the other hand, by using the resin composition obtained by blending the polyisocyanate compound (C) with the hydroxyl group-containing resin (B) as the main component as the above-mentioned crosslinkable clear coating (II), the purpose is The present invention aims to provide a novel topcoating method which comprises forming a coating film.

The present invention will be described in detail below.

That is, in the top coating method of the present invention, generally, the one-component base coat paint (I) is first applied, and then the cross-linked clear paint (II) is further applied to the coated surface thus formed. Then, it is cured.

The oxazoline group-containing vinyl polymer used in the above-mentioned one-pack type base coat paint (I) is, for example, a polymerizable unsaturated monomer having an oxazoline group, and if necessary, other The copolymerizable unsaturated monomer of the form (1) can be obtained by radical polymerization according to a conventional method with various known and commonly used polymerization initiators such as peroxides or azo compounds. Is a vinyl polymer of

Alternatively, a polymerizable unsaturated group is first introduced by addition-reacting various carboxyl group-containing unsaturated monomers such as (meth) acrylic acid with the vinyl polymer. Next, other copolymerizable polymerizable unsaturated monomers are referred to as those obtained by graft-polymerizing by a conventional method, and the above-mentioned ones are particularly representative examples. It is a thing.

Polymerizable unsaturated monomer having oxazoline group (polymerizable unsaturated monomer containing oxazoline group)
As just a typical example,
2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-
Examples include oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline and 2-isopropenyl-5-ethyl-2-oxazoline.

Further, as the above-mentioned other polymerizable unsaturated monomers which can be copolymerized, only representative ones will be exemplified. Styrene, tert-butylstyrene, α-methylstyrene or vinyltoluene. Various aromatic vinyl monomers such as;

Methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, tert-butyl (Meth) acrylate, 2
-Various (meth) acrylates such as ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, dibromopropyl (meth) acrylate or alkoxyalkyl (meth) acrylate;

2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3
-Hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate or polypropylene glycol mono (meth) acrylate Various hydroxyl group-containing (meth) acrylates such as;

Alternatively, the above-mentioned hydroxyl group-containing (meta)
Addition reaction products of acrylates and ε-caprolactone; such as dimethylaminoethyl (meth) acrylate or diethylaminoethyl (meth) acrylate,
Various dialkylaminoalkyl (meth) acrylates;

Tert-Butylaminoethyl (meth) acrylate, tert-butylaminopropyl (meth)
Various amino group-containing monomers such as acrylate; N
-Dimethylaminoethyl (meth) acrylamide, N-
Various amino group-containing amide unsaturated monomers such as diethylaminoethyl (meth) acrylamide, N-dimethylaminopropyl (meth) acrylamide or N-diethylaminopropyl (meth) acrylamide;

Various epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate and β-methylglycidyl (meth) acrylate; vinyl acetate, vinyl benzoate, "Veova" (vinyl ester manufactured by Shell Co., Netherlands) ) Such as vinyl esters; various unsaturated carboxylic acids such as fumaric acid or itaconic acid,
Diesters with monohydric alcohols;

2,3-carbonate propyl (meth) acrylate, 2-methyl-2,3-carbonate propyl (meth) acrylate, 4-methyl-3,4-carbonate butyl (meth) acrylate, 3-methyl-3,
4-carbonate butyl (meth) acrylate, 5-ethyl-5,6-carbonate hexyl (meth) acrylate, 2,3-carbonate propyl vinyl ether,
Methyl-2,3-carbonate propylmalate,

4-vinyloxycarbonylmethyl-2-
Oxo-1,3-dioxolane, 4-methyl-4-vinyloxycarbonylmethyl-2-oxo-1,3-dioxolane, 4- (1-propenyl) oxycarbonylmethyl-2-oxo-1,3-dioxolane, 4 -Vinyloxymethyl-2-oxo-1,3-dioxolane, 4-
(1-Propenyl) oxymethyl-2-oxo-1,3
-Various cyclocarbonate group-containing vinyl monomers such as dioxolane; or vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane or vinylmethyldiethoxysilane,

Vinyl tris (β-methoxyethoxy) silane, allyltrimethoxysilane, trimethoxysilylethyl vinyl ether, triethoxysilylethyl vinyl ether, methyldimethoxysilylethyl vinyl ether, trimethoxysilylpropyl vinyl ether, triethoxysilylpropyl vinyl ether, methyldiethoxy Silylpropyl vinyl ether, γ- (meth) acryloyloxypropyltrimethoxysilane, γ-
Various hydrolyzable silyl group-containing vinyl monomers such as (meth) acryloyloxypropyltriethoxysilane or γ- (meth) acryloyloxypropylmethyldimethoxysilane;

1-methoxyethyl acrylate, 1-ethoxyethyl acrylate, 1-benzyloxyethyl acrylate, 1-cyclohexyloxyethyl acrylate, (1-methoxy-1-methyl) ethyl acrylate, 2-acryloyloxytetrahydrofuran, 2
-Acryloyloxytetrahydropyran, 1-acryloyloxy-1-methoxycyclohexane, 1-methoxyethyl methacrylate, 1-ethoxyethyl methacrylate, 1-isobutoxyethyl methacrylate, 1
-Benzyloxyethyl methacrylate,

1-cyclohexyloxyethyl methacrylate, (1-methoxy-1-methyl) ethyl methacrylate, 2-methacryloyloxytetrahydrofuran, 1-methacryloyloxy-1-methoxycyclohexane, 1-ethoxyethyl crotonate, 2-crot Noyloxytetrahydrofuran, 2-crotonoyloxytetrahydropyran, vinyl 5- (2-ethoxyethoxy) carbonylpentanoate, 5-vinyloxycarbonylpentanoyloxytetrahydrofuran or monobutyl-mono-1-ethoxyethylmalate. Vinyl-based monomers containing a hemiacetal ester group or a hemiketal ester group;

Trimethylsiloxyethyl (meth) acrylate, trimethylsiloxypropyl (meth) acrylate, trimethylsiloxybutyl (meth) acrylate, triethylsiloxyethyl (meth) acrylate,
Various siloxy group-containing vinylic monomers such as tributylsiloxypropyl (meth) acrylate or triphenylsiloxyalkyl (meth) acrylate; or (meth) acrylonitrile, vinyl ethers or vinyl chloride or vinylidene chloride, etc., There are various so-called vinyl-based monomers.

Further, if necessary, as a so-called copolymerizable unsaturated group-containing resin, an unsaturated double bond (hereinafter, also referred to as an unsaturated bond) copolymerizable with unsaturated monomers.
An unsaturated group-containing polyester resin or an unsaturated group-containing alkyd resin having; or an acrylic resin system having an unsaturated bond copolymerizable with an unsaturated monomer, etc. It is also possible to copolymerize.

The oxazoline group-containing vinyl polymer is about 5 to 10 of the oxazoline group-containing unsaturated monomer.
0% by weight and, if necessary, the above-mentioned copolymerizable,
A typical example is one obtained by copolymerizing 0 to about 95% by weight of another polymerizable unsaturated monomer.

The above-mentioned other polymerizable unsaturated monomers may be added, if necessary, from the viewpoints of coating film workability, drying property, weather resistance and gasoline coating resistance. This means that the amount of each component used and the combination thereof may be appropriately determined.

If the amount of the oxazoline group-containing unsaturated monomer used is less than about 5% by weight, it is difficult to obtain sufficient adhesion of the coating film, which is not preferable. .

When preparing the oxazoline group-containing vinyl polymer, a radical polymerization initiator is used.
Respectively, the polymerization reaction may be carried out by making full use of various conventionally known various techniques or means such as solution polymerization, bulk polymerization, suspension polymerization or emulsion polymerization.

[0039] To exemplify only the typical radical polymerization initiators to be used at that time, various diacyl peroxides such as acetyl peroxide or benzoyl peroxide, and the like, Is

Various ketone peroxides such as methyl ethyl ketone peroxide or cyclohexanone peroxide; or various hydroperoxides such as hydrogen peroxide, tert-butyl hydroperoxide or cumene hydroperoxide;
Or

Various dialkyl peroxides such as di-tert-butyl peroxide or dicumyl peroxide; alkyl peroxyesters such as tert-butyl peroxyacetate or tert-butyl perbutyl pivalate;

Or various azo compounds such as azobisisobutyronitrile or azobisisovaleronitrile, and further various persulfates such as potassium persulfate or ammonium persulfate. .

The polymerization reaction method is as described above.
There are various known and commonly used methods, and among them, it is preferable to use bulk polymerization or solution polymerization, and further, in the form of the obtained copolymer as it is, for example, a resin for solution type coating. From the viewpoint of being usable as a composition, the solution polymerization method is particularly preferable.

According to such a solution polymerization method, only representative ones of the solvents used for preparing the oxazoline group-containing vinyl copolymer will be exemplified. For example, benzene, toluene or xylene can be used.
Various aromatic hydrocarbons; various aliphatic hydrocarbons such as n-pentane, n-hexane or n-octane; various alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclohexane or ethylcyclohexane Kinds; various mixed hydrocarbons such as mineral spirits;

Methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, n-pentanol, isopentanol, n-hexanol, n-octanol, 2
-Ethylhexanol, cyclohexanol, cyclohexanol, ethylene glycol monomethyl ether,
Various alcohols such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether or propylene glycol monoethyl ether;

Dimethoxyethane, tetrahydrofuran,
Dioxane, diisopropyl ether or di-n-
Various ethers such as butyl ether; acetone,
Various ketones such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, methyl amyl ketone, cyclohexanone or isophorone; methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, amyl acetate, ethylene Various esters such as glycol monomethyl ether acetate or ethylene glycol monobutyl ether acetate, and N-
Such as methylpyrrolidone, dimethylformamide, dimethylacetamide or ethylene carbonate.

Of course, these organic solvents listed above may be used alone or in combination of two or more.

From the various monomer components as listed above,
To prepare the oxazoline group-containing vinyl polymer by the solution polymerization method, all the monomers, the polymerization initiators and the solvents are charged into a reaction vessel at once and polymerized, or only the solvents are used. In a reaction vessel charged with, all the monomers and the polymerization initiators are added continuously or in a divided manner to polymerize,
Various methods can be applied.

Further, the oxazoline group-containing vinyl polymer may be a so-called non-aqueous dispersion type in which it is dispersed in a solvent.

The oxazoline group-containing vinyl polymer thus obtained has a weight average molecular weight of about 3,000.
0 to about 300,000, especially 5,0
It is desirable to manage so as to fall within the range of 0-250,000.

When it is less than 3,000,
The solvent resistance of the coating film tends to decrease, while
If it exceeds 300,000, the workability of coating tends to be difficult, and thus it is not preferable in any case.

Next, only representative examples of the above-mentioned cellulose derivative (D), which is another constituent component used in combination with the above-mentioned vinyl polymer (A) containing an oxazoline group, will be exemplified. , Nitrocellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, methyl cellulose, ethyl cellulose, benzyl cellulose and the like, among which nitrocellulose or cellulose acetate butyrate is preferable.

The blending ratio of the cellulose derivative (D) to the oxazoline group-containing vinyl polymer (A) is 100 parts by weight of the oxazoline group-containing vinyl polymer (A). The range in which the cellulose derivative (D) is about 5 to about 250 parts by weight is suitable from the viewpoint of various properties of the coating film.

That is, when the amount of the cellulose derivative (D) is less than 5 parts by weight with respect to 100 parts by weight of the oxazoline group-containing vinyl polymer (A), sufficient coating film performance is inevitable. In addition, it is difficult to obtain a product having a shape with a certain amount, and on the other hand, when it is used in excess of 250 parts by weight, the coating workability and the coating appearance are liable to deteriorate. Absent.

When the desired one-pack type base coat coating composition is prepared using the above-mentioned oxazoline group-containing vinyl polymer (A) and the cellulose derivative (D), further, if necessary, It can also be said that a plasticizer is used.

Specific examples of the above-mentioned plasticizers include, but are not limited to, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, diheptyl phthalate, dioctyl phthalate, didecyl phthalate, Various phthalates such as diisodecyl phthalate, ditridecyl phthalate, butylbenzyl phthalate; various phthalates such as diisodecyl succinate, dioctyl adipate, diisodecyl adipate, dioctyl azelate, dibutyl sebacate, dioctyl sebacate Aliphatic dibasic acid esters;

Various phosphates such as tributyl phosphate, trioctyl phosphate, tricresyl phosphate, triphenyl phosphate; various dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid and phthalic acid. Acids, ethylene glycol,
1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol or 1,4-butanediol, 1,6-hexanediol or diethylene glycol or triethylene glycol, Various polyesters obtained by reaction with various glycols; or epoxidized soybean oil or epoxidized fatty acid ester.

The amount of the plasticizer used is 100 parts by weight of the total amount of the oxazoline group-containing vinyl polymer (A) and the cellulose derivative (D).
It is desirable from the viewpoint of various performances of the coating film that the amount of the plasticizer is 0 to about 40 parts by weight.

That is, the total amount of the oxazoline group-containing vinyl polymer (A) and the cellulose derivative (D) is 100.
When the amount of the plasticizer exceeds about 40 parts by weight with respect to parts by weight, the drying property and the finished appearance are likely to deteriorate, which is not preferable.

The one-pack type base coat paint used in the present invention can be used as it is as a clear paint, and various metal powders such as aluminum, gold, silver, copper or brass, or inorganic pigments and organic pigments can be used. ,
It can also be used in the form of using various coloring pigments such as organic dyes or scaly mica powder.

Further, if necessary, various resins, solvents, etc., flow regulators, color separation inhibitors, antioxidants, ultraviolet absorbers, light stabilizers, silane coupling agents, etc. Needless to say, various known and commonly used additives can be added.

Examples of the above various resins include ketone resins, petroleum resins, acrylic polymers, oil-free alkyd resins, alkyd resins, and epoxy resins.

As the above-mentioned solvents, the same various solvents as those used for preparing the oxazoline group-containing vinyl polymer (A) or a mixture thereof can be used.

Next, the above-mentioned cross-linkable clear paint (I
I) will be described in detail.

The above-mentioned hydroxyl group-containing resin (B) used in the crosslinkable clear paint basically refers to a crosslinkable resin having at least two hydroxyl groups in one molecule. Above all, it is desirable to use a hydroxyl group-containing acrylic resin, a hydroxyl group-containing fluororesin or a hydroxyl group-containing polyester resin. Needless to say, these hydroxyl group-containing resins may be used alone or in combination of two or more kinds.

The above-mentioned hydroxyl group-containing acrylic resin is obtained by combining hydroxyl group-containing vinyl monomers and other copolymerizable vinyl monomers according to a conventional method such as peroxides or azo compounds. A typical example is the one obtained by radical polymerization with various known and commonly used polymerization initiators.

As only specific examples of such hydroxyl group-containing vinyl monomers, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) are listed. ) Acrylate, 2-hydroxybutyl (meth)
Various hydroxyl group-containing (meth) acrylates such as acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate or polypropylene glycol mono (meth) acrylate; or These are addition reaction products of the above-mentioned various (meth) acrylates and ε-caprolactone.

And, only by exemplifying particularly representative ones of the above-mentioned other copolymerizable vinyl monomers, styrene, tert-butylstyrene, α-
Various aromatic vinyl monomers such as methylstyrene or vinyltoluene; methyl (meth) acrylate,
Ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate,
n-butyl (meth) acrylate, iso-butyl methacrylate, tert-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate or lauryl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, dibromopropyl Various (meth) acrylates such as (meth) acrylate or alkoxyalkyl (meth) acrylate
Acrylates;

Various carboxyl group-containing monomers such as (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid or fumaric acid, or various polyvalent carboxyl groups such as itaconic acid, maleic acid or fumaric acid Monoesters of contained monomers and monoalkyl alcohols having 1 to 18 carbon atoms; N-dimethylaminoethyl (meth) acrylamide, N-diethylaminoethyl (meth) acrylamide, N-dimethylaminopropyl (meth) acrylamide Or various amino group-containing amide unsaturated monomers such as N-diethylaminopropyl acrylamide;

Various epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate or β-methylglycidyl (meth) acrylate; vinyl acetate, vinyl benzoate or "Veoba" (Vinyl, manufactured by Shell Co., Netherlands) Various vinyl esters such as (trade name of ester); various unsaturated carboxylic acids such as fumaric acid or itaconic acid, and various such as methyl alcohol (methanol) ethyl alcohol (ethanol) or butyl alcohol (butanol) Diesters with monohydric alcohols;

Dialkyl (meth) acryloyloxyalkyl phosphates, (meth) acryloyloxyalkyl acid phosphates, dialkyl (meth)
Acryloyloxyalkyl phosphites and (meth)
Acryloyloxyalkyl phosphites; various cyano group-containing vinyl monomers such as (meth) acrylonitrile; vinyl ethers; and various vinyl halides such as vinyl chloride or vinylidene chloride.

Further, if necessary, as a so-called copolymerizable unsaturated group-containing resin, for example, a so-called copolymerizable unsaturated monomer containing each of the above-mentioned various vinyl monomers may be used. An oil or fatty acid-modified form of a so-called alkyd resin having a polymerizable unsaturated double bond;

Alternatively, an unsaturated bond-containing polyester resin having an unsaturated double bond that is copolymerizable with the polymerizable unsaturated monomer; or, an unsaturated bond-containing polyester resin that is copolymerizable with the polymerizable unsaturated monomer. It is also possible to copolymerize such copolymerizable unsaturated group-containing resins with an acrylic resin having a saturated double bond.

Next, the hydroxyl group-containing fluororesin means, for example, a fluoroolefin, a hydroxyl group-containing vinyl monomer, and another copolymerizable vinyl monomer, and the peroxides or the azo compound are produced by a conventional method. Typical examples are those obtained by radical polymerization with various known and commonly used polymerization initiators such as the above.

As the above-mentioned fluoroolefins, only typical ones are exemplified. Vinyl fluoride, vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, chlorotrifluoroolefin, bromotrifluoroethylene, pentafluoro. Various fluorine-containing α-olefins such as propylene or hexafluoropropylene;

Or various compounds such as various perfluoroalkyl perfluorovinyl ethers such as trifluoromethyl trifluorovinyl ether or pentafluoroethyl trifluorovinyl ether, among which hexafluoropropylene, tetrafluoro The use of ethylene, chlorotrifluoroethylene, vinyl fluoride or vinylidene fluoride is preferred.

Further, only representative examples of the hydroxyl group-containing vinyl monomer are given as examples: 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 2-hydroxypropyl ether, 4
Various hydroxy group-containing vinyl ethers such as -hydroxybutyl vinyl ether, 3-hydroxybutyl vinyl ether, 2-hydroxy-2-methylpropyl vinyl ether, 5-hydroxypentyl vinyl ether or 6-hydroxyhexyl vinyl ether;

In addition to the addition reaction products of various vinyl ethers and ε-caprolactone as described above, 2-hydroxyethyl (meth) allyl ether, 3-hydroxypropyl (meth) allyl ether, 2-hydroxypropyl (meth) allyl ether, 4-hydroxybutyl (meth) allyl ether, 3
-Hydroxybutyl (meth) allyl ether, 2-hydroxy-2-methylpropyl (meth) allyl ether,
Various hydroxyl group-containing allyl ethers such as 5-hydroxypentyl (meth) allyl ether or 6-hydroxyhexyl (meth) allyl ether;

Various allyl ethers as listed above,
and an addition reaction product with ε-caprolactone,
Furthermore, as described above, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3
Various hydroxy group-containing (meth) acrylates such as -hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate or polypropylene glycol mono (meth) acrylate; These are addition reaction products of the various (meth) acrylates listed above and ε-caprolactone.

And, only by exemplifying particularly representative ones of the above-mentioned other copolymerizable vinyl monomers, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether and n-butyl are given. Vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, n
-Pentyl vinyl ether, n-hexyl vinyl ether, n-octyl vinyl ether or 2-ethylhexyl vinyl ether, chloromethyl vinyl ether,
Various alkyl vinyl ethers or substituted alkyl vinyl ethers such as chloroethyl vinyl ether, benzyl vinyl ether or phenylethyl vinyl ether;

Or cyclopentyl vinyl ether,
Various cycloalkyl vinyl ethers such as cyclohexyl vinyl ether or methyl cyclohexyl vinyl ether; vinyl-2,2-dimethylpropanoate, vinyl-2,2-dimethylbutanoate, vinyl-2,2-dimethylpentanoate, vinyl -2,2-
Dimethyl hexanoate, vinyl-2-ethyl-2-methylbutanoate, vinyl-2-ethyl-2-methylpentanoate, vinyl-3-chloro-2,2-dimethylpropanoate,

Vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl caproate, vinyl caprylate, vinyl caprate or vinyl laurate,
Various aliphatic vinyl carboxylates such as C ₉ aliphatic vinyl carboxylates, C ₁₀ branched aliphatic vinyl carboxylates, C ₁₁ branched aliphatic vinyl carboxylates or vinyl stearate;

Various vinyl esters of carboxylic acids having a cyclic structure, such as vinyl cyclohexanecarboxylate or vinyl methylcyclohexanecarboxylate or vinyl benzoate or vinyl p-tert-butylbenzoate; methyl acrylate, ethyl acrylate, butyl acrylate. Or various acrylic acid esters such as cyclohexyl acrylate; various methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate or benzyl methacrylate;

Ethylene, propylene or butene-1
, Various kinds of α-olefins, such as vinyl chloride or vinylidene chloride, various kinds of halogenated olefins other than fluoroolefins, such as styrene, α-methylstyrene or vinyltoluene, various aromatic vinyl compounds, vinyl Trimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinylmethyldiethoxysilane, vinyltris (β-methoxyethoxy) silane, allyltrimethoxysilane,

Trimethoxysilyl vinyl ether, triethoxysiethyl vinyl ether, methyldimethoxysilylethyl vinyl ether, trimethoxysilylpropyl vinyl ether, triethoxysilylpropyl vinyl ether, methyldiethoxysilylpropyl vinyl ether, γ- (meth) acryloyloxypropyltrimethoxysilane Various compounds having a hydrolyzable silyl group, such as γ- (meth) acryloyloxypropyltriethoxysilane or γ- (meth) acryloyloxypropylmethyldimethoxysilane;

Various amino group-containing amide systems such as N-dimethylaminoethyl (meth) acrylamide, N-diethylaminoethyl (meth) acrylamide, N-dimethylaminopropyl (meth) acrylamide or N-diethylaminopropyl (meth) acrylamide. Unsaturated monomers; various dialkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate or diethylaminoethyl (meth) acrylate;

Tert-Butylaminoethyl (meth) acrylate, tert-butylaminopropyl (meth)
Various amino group-containing monomers such as acrylate, aziridinylethyl (meth) acrylate, pyrrolidinylethyl (meth) acrylate or piperidinylethyl (meth) acrylate; or (meth) acrylic acid,
Examples include various carboxyl group-containing monomers such as crotonic acid, itaconic acid, maleic acid or fumaric acid.

The above-mentioned hydroxyl group-containing polyester resin is typified by that obtained by esterifying a polybasic acid component and a glycol component according to a conventional method.

Specific examples of such polybasic acid components include only phthalic acid, isophthalic acid, terephthalic acid, methylterephthalic acid, trimellitic acid or pyromellitic acid or their anhydrides. , Various aromatic dicarboxylic acids; hexahydrophthalic acid, tetrahydrophthalic acid, methylhexahydrophthalic acid or methyltetrahydrophthalic acid or their anhydrides,

Various alicyclic dicarboxylic acids; or various aliphatic dicarboxylic acids such as succinic acid, maleic acid, adipic acid, azelaic acid, sebacic acid or dodecanedioic acid or their anhydrides; Are benzoic acid, para-tertiary benzoic acid or versatic acid.

On the other hand, if only typical examples of the glycol component are given, ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, neopentyl. Glycol, triethylene glycol, cyclohexanedimethanol, hydrogenated bisphenol A or glycerin,

In addition to trimethylolethane, trimethylolpropane, pentaerythritol and the like, further, "CARDURA E" [branched (branched) aliphatic monoepoxy compound manufactured by Shell Co. of the Netherlands] and the like. Various monoepoxy compounds can also be used as the glycol component.

Further, an oil component may be used as one of the resin-forming components in the polyester resin, but from the viewpoint of weather resistance, coconut oil,
The use of hydrogenated coconut oil, octylic acid, isononanoic acid and the like is desirable, and if necessary, rice bran oil fatty acid, tall oil fatty acid, soybean oil, castor oil or dehydrated castor oil can also be appropriately used.

The hydroxyl group-containing resin (B) thus obtained has a solid content hydroxyl value (hereinafter abbreviated as a hydroxyl value) within a range of about 30 to about 300 from the viewpoint of coating film performance. Are also suitable.

That is, when the hydroxyl value of the hydroxyl group-containing resin (B) is less than about 30, the solvent resistance of the coating film tends to be inevitably deteriorated, while about 3
If the value exceeds 00 and becomes too high, the drying property and the like are inevitably deteriorated, and thus either case is not preferable.

Next, the cross-linkable clear coating composition (I
The above-mentioned polyisocyanate compound (C) used in I) refers to, for example, one having at least two isocyanate groups in one molecule.
Of these, only typical ones are listed, and various aromatic diisocyanates such as tolylene diisocyanate or diphenylmethane diisocyanate;

Various aliphatic diisocyanates such as hexamethylene diisocyanate or trimethylhexane diisocyanate; organic diisocyanate compounds such as various alicyclic diisocyanates such as xylylene diisocyanate or isophorone diisocyanate;

With these organic diisocyanate compounds,
Examples thereof include polyhydric alcohols, low molecular weight polyester resins, adducts with water, and the like, or polymers of the organic diisocyanate compounds described above (including isocyanurate type polyisocyanate compounds).

Needless to say, these polyisocyanate compounds may be used alone or in combination of two or more kinds.

Such polyisocyanate compound (C)
The compounding ratio of the above-mentioned hydroxyl group-containing resin (B) is preferably in the range of NCO / OH = about 0.5 to about 2.0 (equivalent ratio) from the viewpoint of various properties of the coating film. .

When preparing the crosslinkable clear coating composition (II) used in the present invention, various known and commonly used curing catalysts can be used, if necessary.

As only such typical curing catalysts, dibutyltin dilaurate,
Various organometallic compounds such as dibutyltin diacetate, tin dioctylate or cobalt naphthenate; or 1,4-diazabicyclo- (2,2,2) -octane or 1,8-diazabicyclo- (5,4,0) ) -Undecene-7 and various amine compounds.

Furthermore, if necessary, various known conventional materials such as various resins and solvents, flow regulators, antioxidants, ultraviolet absorbers, light stabilizers, silane coupling agents and the like can be used. Of course, it is possible to add the additives.

[0100] To give only a representative example of the various resins mentioned above, various fibrin-based resins such as nitrocellulose or cellulose acetate butyrate, and further, a ketone resin can be used. ,
It is a petroleum resin, a silicone resin or an epoxy resin, and also includes organic silicates and the like.

Further, the above-mentioned solvents include various solvents or a mixture thereof, which are used for preparing the above-mentioned vinyl polymer (A) containing an oxazoline group, as described above, These various compounds are exemplified as particularly representative ones.

In order to form a desired coating film according to the overcoating method of the present invention, for example, a primer or a surfacer is applied on the surface-treated object to be coated, or if necessary, in advance. On the coated object, or on the coated object with the top coating,

The one-pack type base coat paint (I) is applied as it is, in a form diluted with a diluting solvent, if necessary, by a conventional method, and then crosslinked clear paint (II). ) May be coated according to a conventional method and crosslinked under desired conditions.

Needless to say, the top coat film of the present invention obtained in this manner is particularly excellent in durability and appearance of the coat film. Needless to say, a conventional one-component base coat paint composition is used. Compared to the method, it is particularly excellent in adhesion to the underlying coating film and water resistance.

Therefore, as described in detail above, the overcoating method of the present invention is a highly practical coating method particularly for various coatings such as automobile top coats and automobile repairs.

Further, the top coating method of the present invention can be applied very effectively to applications other than those described above, for example, coating methods for building exteriors, building materials or heavy corrosion protection. You can do it.

[0107]

EXAMPLES Next, the present invention will be explained more specifically by reference examples, examples and comparative examples, but the present invention is by no means limited to these illustrative examples. Not like that.

In the following, all parts and% are based on weight unless otherwise specified.

Reference Example 1 [Preparation Example of Oxazoline Group-Containing Vinyl Polymer (A)] In a four-necked flask equipped with a stirrer, a thermometer, a condenser and a nitrogen introducing tube, 400 parts of toluene and n-acetic acid were added. It was charged with 100 parts of butyl and kept at 100 ° C.

Then, a mixture of 250 parts of methyl methacrylate, 120 parts of n-butyl methacrylate and 50 parts of n-butyl acrylate, and 80 parts of 2-isopropenyl-2-oxazoline was added thereto, and polymerization was initiated. A mixture of 3 parts of tert-butyl peroxy octoate and 1 part of tert-butyl peroxybenzoate, respectively, as an agent was added dropwise over 4 hours.

After the dropping was completed, the reaction was continued at the same temperature for 8 hours to obtain a solution of the target resin (A) having a nonvolatile content of 50%. Hereinafter, this is a resin (A-1)
Abbreviated.

Reference Example 2 (same as above) The vinyl monomer to be used was methyl methacrylate 2
50 parts, 100 parts of n-butyl methacrylate and n
-Change with 100 parts of butyl acrylate, and 2-
A reaction was performed in the same manner as in Reference Example 1 except that the amount of isopropenyl-2-oxazoline used was changed to 50 parts to give a solution of the target resin (A) having a nonvolatile content of 50%. Obtained. Hereinafter, this is a resin (A-
2) is abbreviated.

Reference Example 3 [One-component base coat paint (I)]
Preparation Example] A mixture prepared according to a usual paint preparation method with the following composition ratios was diluted with a solvent for dilution to Ford Cup NO. By adjusting the viscosity to 12 seconds, the intended one-component base coat paint was obtained.

Resin (A-1) obtained in Reference Example 1 100 parts “CAB551-0.2” 25 parts (trade name of cellulose acetate butyrate manufactured by US Eastman Kodak Company) “CAB531-1” 25 Part (trade name of cellulose acetate butyrate manufactured by US Eastman Kodak Company) "Disparlon 4200-10" 4 parts [trade name of polyethylene wax manufactured by Kusumoto Kasei Co., Ltd.] "Alpaste 7160N" 30 parts [Toyo Product name of aluminum paste manufactured by Aluminum Co., Ltd.] ────────────────────────────────── 184 parts

Hereinafter, this is abbreviated as BC-1.

Reference Example 4 (Same as above) Ford cup NO. By adjusting the viscosity to 12 seconds, the intended one-component base coat paint was obtained.

Resin (A-2) obtained in Reference Example 2 100 parts “CAB551-0.2” 25 parts “CAB531-1” 25 parts “Disparlon 4200-10” 4 parts “Alpaste 7160N” 30 parts ───────────────────────────────── 184

Hereinafter, this is abbreviated as BC-2.

Reference Example 5 [Preparation Example of Crosslinkable Clear Paint (II)] Ford cup NO. In step 4, the viscosity was adjusted to 20 seconds to obtain the desired crosslinkable clear paint.

"Acridic 54-630" 100 parts [Product name of hydroxyl group-containing acrylic resin manufactured by Dainippon Ink and Chemicals; non-volatile content = 60%] "Burnock DN-980" 26 parts [Dainippon Ink Co., Ltd. Product name of polyisocyanate compound manufactured by Kagaku Kogyo Co., Ltd .; nonvolatile content = 75%] "Tinuvin 900" 1 part (trade name of UV absorber manufactured by Ciba-Geigy, Switzerland) "Sanol LS-765" 1 part [Product name of light stabilizer manufactured by Sankyo Co., Ltd.] ───────────────────────────────── 128 parts

Hereinafter, this is abbreviated as CC-1.

Reference Example 6 (Same as above) [0122] Ford cup NO. In step 4, the viscosity was adjusted to 20 seconds to obtain the desired crosslinkable clear paint.

"Fluoronate K-704" 100 parts [Product name of fluorine-containing fluororesin manufactured by Dainippon Ink and Chemicals, Inc .; nonvolatile content = 60%] "Bernock DN-990S" 12 parts [Dainippon Ink and Chemicals, Inc. Trade name of polyisocyanate compound manufactured by Kogyo Co., Ltd .; nonvolatile content = 100%] "Tinuvin 900" 1 part "Sanol LS-765" 1 part ───────────────── ──────────────── 114 copies

Hereinafter, this is abbreviated as CC-2.

Reference Example 7 (Same as above) [0125] Ford cup NO. In step 4, the viscosity was adjusted to 20 seconds to obtain the desired crosslinkable clear paint.

“Beckol CB-931” 100 parts [trade name of hydroxyl group-containing alkyd resin manufactured by Dainippon Ink and Chemicals, Inc .; nonvolatile content = 65%] “Bernock DN-980” 31 parts “Tinuvin 900” 1 Part "Sanol LS-765" 1 part ───────────────────────────────── 133 parts

Hereinafter, this is abbreviated as CC-3.

Reference Example 8 (Preparation Example of Acrylic / Melamine Base Coat Paint) A mixture prepared according to a conventional paint preparation method at the following compounding ratio was diluted with Ford Cup NO. By adjusting the viscosity to 12 seconds, the intended acrylic / melamine-based base coat paint was obtained.

“Acridic A-322” 100 parts [Product name of hydroxyl group-containing acrylic resin manufactured by Dainippon Ink and Chemicals; non-volatile content = 50%] “Super Beckamine L-117-60” 21 parts [Product name of n-butylated melamine resin manufactured by Dainippon Ink and Chemicals, Inc .; nonvolatile content = 60%] "Alpaste 7160N" 16 parts ───────────────── ──────────────── 137 copies

Hereinafter, this is abbreviated as BC-3.

Reference Example 9 (Preparation Example of Acrylic / Melamine-Based Clear Paint) A mixture prepared by the usual paint preparation method at the following blending ratio was diluted with a solvent for Ford Cup NO. By adjusting the viscosity to 4 for 20 seconds, the intended acrylic / melamine-based clear paint was obtained.

"Acridic A-345" 100 parts [Product name of hydroxyl group-containing acrylic resin manufactured by Dainippon Ink and Chemicals, Inc .; nonvolatile content = 55%] "Super Beckamine L-117-60" 40 parts "Tinubin 900" 1 part "Sanol LS-765" 1 part ───────────────────────────────── 142 parts

Hereinafter, this is abbreviated as CC-4.

Reference Example 10 (Preparation Example of Control Resin) The vinyl monomer to be used was methyl methacrylate 2
80 parts, 170 parts of n-butyl methacrylate and n
The reaction was carried out in the same manner as in Reference Example 1 except that the content of butyl acrylate was changed to 50 parts.
A 0% control solution of the resin was obtained. Hereinafter, this is abbreviated as a control resin (A-3).

Reference Example 11 (Preparation example of one-component base coat paint for control) A mixture prepared by an ordinary paint preparation method so as to have the following proportions was diluted with Ford Cup NO.
The viscosity was adjusted to 4 seconds for 12 seconds to obtain a one-pack type base coat paint.

Control resin (A-3) obtained in Reference Example 10 100 parts “CAB551-0.2” 25 parts “CAB531-1” 25 parts “Disparlon 4200-10” 4 parts “Alpaste 7160N” 30 ──────────────────────────────── 184

Hereinafter, this is abbreviated as BC-4.

Examples 1 to 6 and Comparative Examples 1 and 2 On a mild steel plate, a cationic electrodeposition coating film and a polyester / melamine type surfacer were applied, and the acrylic / melamine type base coat obtained in Reference Example 8 was applied. Paint (BC-
3) was applied by air spraying so that the dry film thickness was 15 to 20 μm.

Next, after setting for 5 minutes, the acrylic melamine clear coating composition (CC-4) obtained in Reference Example 9 was air sprayed to give a dry film thickness of 35 to 40 μm. After coating wet-on-wet, it was left at room temperature for 20 minutes and then baked and dried at 140 ° C. for 30 minutes.

Further, after 24 hours, the thus obtained coated plate was polished with # 2000 paper, and then each one-component base coat paint (I) obtained in Reference Example 3, 4 or 11 was used. By air spray
The coating was applied so that the dry film thickness was 20 to 30 μm.

Then, after setting for 15 minutes, the crosslinkable clear coating composition (II) obtained in Reference Example 5, 6 or 7 was air sprayed to give a dry film thickness of 50 to 50
After coating with wet-on-wet so as to have a thickness of 60 μm, it was dried at 60 ° C. for 30 minutes and then left at room temperature for 1 week.

After that, each of the thus-obtained test pieces was subjected to various coating performance evaluation / judgment tests. The results are summarized in Table 1.

[0143]

[Table 1]

<< Footnotes in Table 1 >> 1) Gloss value: It was expressed as a 60 degree specular reflectance (%).

2) Vividness: Judged visually.

A: Very good B: Somewhat bad X: Bad

3) Adhesiveness: 100 at 2 mm intervals
A checkerboard was put in, and the presence or absence of peeling due to cellophane tape peeling was visually determined.

∘: No peeling was observed at all △: Some peeling was observed ×: Remarkably peeling

4) Water resistance: Immersion in warm water of 40 ° C. for 72 hours, and immediately after taking out, visually judging the presence or absence of blisters on the coated surface (ASTM).
D-714) and the adhesiveness after standing at room temperature for 24 hours were visually determined.

[0150]

[Table 2]

[0151]

INDUSTRIAL APPLICABILITY As described in detail above, the present invention is particularly excellent in adhesion to a base coating film and blister resistance, and in addition to being excellent in appearance of a coating film. Therefore, a useful coating method can be provided.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B05D 7/24 302 B05D 7/24 302F 302R 303 303C

Claims (4)

[Claims] 1. A one-pack type base coat paint (I) containing a metal powder and / or a coloring pigment is applied onto an object to be coated, and then the cross-linked clear paint (II) is applied to the coated surface.
The above-mentioned one-component type base coat paint (I)
As the vinyl polymer (A) containing an oxazoline group,
While being used as an essential component, the above-mentioned cross-linkable clear coating (II) can be used as a hydroxyl group-containing resin (B).
A coating method is characterized in that a coating film is formed by using as a main component a resin composition obtained by mixing the polyisocyanate compound (C) with the above. 2. A one-pack type base coat paint (I) containing a metal powder and / or a coloring pigment is applied onto an object to be coated, and then the cross-linked clear paint (II) is applied to the coated surface.
The above-mentioned one-component type base coat paint (I)
As the oxazoline group-containing vinyl polymer (A),
While the resin composition obtained by blending the cellulose derivative (D) is used as a main component, a hydroxyl group-containing resin (B) is used as the above-mentioned crosslinkable clear coating (II).
A coating method is characterized in that a coating film is formed by using as a main component a resin composition obtained by mixing the polyisocyanate compound (C) with the above. 3. The hydroxyl group-containing resin (B) is at least one selected from the group consisting of hydroxyl group-containing acrylic resin, hydroxyl group-containing fluororesin and hydroxyl group-containing polyester resin, according to claim 1 or 2. Top coating method described. 4. The topcoat coating method according to claim 2, wherein the cellulose derivative (D) is cellulose acetate butyrate or nitrocellulose.