JPH0461969A - Topcoating method - Google Patents

Abstract

PURPOSE:To obtain a painted article excellent in scratch resistance, acid resistance and weatherability by applying topcoat paint containing a specific fluorine- containing polymer and a specific isocyanate component as essential components to cure the same. CONSTITUTION:Topcoating paint containing a fluorine-containing polymer (A) containing at least two hydroxyl groups in one molecule thereof on an average and an isocyanate compound (B) having an isocyanurate ring obtained by reacting a diisocyanate compound and 10-40C diol in the presence of an isocyanuration catalyst as essential components is applied to an article to be coated having an undercoat paint film formed thereto. The topcoat paint may be applied in such a state that undercoat paint is uncured or cured. After painting, the painted article is dried at room temp. for 3 days or dried at 60-300 deg.C for several sec-60min to form a cured film.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel and useful topcoating method. More specifically, the present invention provides a specific coating comprising a hydroxyl group-containing fluorine-containing vinyl polymer and an isocyanurate ring-containing isocyanate compound as essential components on a coated object on which a coating film of an undercoat is formed. The present invention relates to a coating method that uses a top coat to form a top coat that has long-term weather resistance, scratch resistance, and chemical resistance.

[Conventional technology]

Until now, the top coating methods for automobile bodies, etc.
Topcoats using melamine alkyd resins and melamine acrylic resins have been used.

However, the coating films obtained by applying these top coats tend to lose their gloss or fade in color during long-term use.

In order to solve these problems, a method using a fluororesin as a top coat has also been proposed.

(Unexamined Japanese Patent Publication No. 197074/1983 or Unexamined Japanese Patent Publication No. 1983-
264175).

According to these methods, a coating film with extremely excellent long-term weather resistance can be obtained, but the scratch resistance is not sufficient.

The term "scratch resistance" as used herein refers to durability against scratches caused by conventional hair dusters, automatic car wash brushes, etc., and is particularly strongly required for dark-colored paint films.

Furthermore, in recent years, paint film damage due to acid rain, which is thought to be caused by sulfur oxides and nitrogen oxides released into the atmosphere, has become a problem, and countermeasures are required.

As one of the countermeasures, changing the curing agent from melamine resin to isocyanate compound can greatly improve the acid resistance, but on the other hand, the scratch resistance will deteriorate, making it impractical. It wasn't.

[Problem to be solved by the invention]

In this way, as long as conventional techniques such as those mentioned above were followed, it was never possible to obtain a top coat that had both long-term weather resistance and scratch resistance, as well as chemical resistance. .

For this reason, the present inventors have begun intensive research in search of a top coat that has both such long-term weather resistance and scratch resistance, and also has chemical resistance.

Therefore, the object of the present invention is to provide a top coat paint which solves all the problems in the prior art as described above, has extremely excellent long-term weather resistance, and is also excellent in acid resistance and scratch resistance. The purpose is to provide a novel coating method using.

[Means to solve the problem]

Therefore, as a result of intensive studies mainly in line with the problems to be solved by the invention as described above, the present inventors have developed a method that contains a specific fluorine-containing polymer and a specific isocyanate compound as essential components. The present inventors discovered that by applying and curing a top coat of the following, it is possible to obtain a coated product with extremely high scratch resistance, as well as excellent acid resistance and weather resistance, and have thus completed the present invention. Ta.

That is, the present invention applies a fluorine-containing vinyl polymer (A) containing an average of at least two hydroxyl groups per molecule as an essential component to a coated object on which an undercoat film is formed. , a diisocyanate compound and a carbon number of 10 to 4
The object of the present invention is to provide a method for applying a top coat comprising an isocyanate compound (B) having an isocyanurate ring, which is obtained by reacting diol 0 in the presence of an isocyanurate-forming catalyst.

First, the above-mentioned undercoat is an organic solvent type, non-aqueous dispersion type, water soluble type or A general term for water-dispersed paints, including solvents,
Of course, it may contain additives and modifiers.

To exemplify only typical examples of the resin composition, a main resin such as an acrylic resin, an alkyd resin, a polyester resin, an epoxy resin, a cellulose resin, or a vinyl resin, and an amine resin or a polyisocyanate compound, etc. There are thermosetting and room-temperature curing types that consist of a curing agent.

Of course, a thermoplastic resin composition that does not use a curing agent can also be used, but any curable resin composition is preferred from the viewpoint of long-term weather resistance.

Next, the above-mentioned top coating paint will be explained. The above-mentioned hydroxyl group-containing fluorine-containing vinyl polymer (A) is
- It has two or more hydroxyl groups on average in its molecule, and if the number of hydroxyl groups contained is less than two, it is not preferred because the durability of the coating film will decrease.

The hydroxyl group-containing dental fluorinated vinyl polymer (A) contains 15 to 75% by weight of the fluorinated vinyl monomer (a-1).
and 5 to 40% of the hydroxyl group-containing vinyl monomer (a-2)
5 to 85% by weight of other monomer (a-3) copolymerizable with
A typical example is one obtained by copolymerizing these.

If the amount of the fluorine-containing vinyl monomer (a-1) used is less than the above range, the durability of the coating film will decrease, whereas if it exceeds the above range, Both of these methods are undesirable, since they result in a decrease in painting workability.

In addition, if the amount of the hydroxyl group-containing vinyl monomer (a-2) is less than the above range, the solvent resistance and durability of the coating film will decrease; If it exceeds the range, the flexibility of the coating film will deteriorate, which is not preferable.

Typical examples of the dental fluorinated vinyl monomer (a-1) include vinylbutylene, vinylidenebutylidene, trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, and promotrifluoroethylene. Ethylene, pentafluoropropylene or
Fluorine-containing α-olefins such as hexafluoropropylene; or perfluoroalkyl perfluorovinyl ethers such as trifluoromethyl trifluorovinyl ether, pentafluoroethyl trifluorovinyl ether or heptafluoroprobyl trifluorovinyl ether; Alkyl vinyl ether (however, the number of carbon atoms in the alkyl group is 1 to 1)
It is within the range of 8. ), among others,
Use of fluorinated vinyl, tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, (per)fluoroalkyl vinyl ether in which the alkyl group has 1 to 18 carbon atoms, or perfluoroalkyl trifluorovinyl ether in which the alkyl group has Cl-C18. is desirable.

Particularly representative examples of the hydroxyl group-containing vinyl monomer (a-2) include 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 2-hydroquine furopyl vinyl ether, and 4-hydroxypropyl vinyl ether.
- Vinyl ethers having a hydroxyl group such as hydroxybutyl vinyl ether, 3-hydroxybutyl vinyl ether, 2-hydroxy-2-methylpropyl vinyl ether, 5-hydroxypentyl vinyl ether, or 6-hydroxyethyl vinyl ether; these various vinyl ethers and ε - Addition reaction product with caprolactone; 2-hydroxyethyl (meth)allyl ether,
3-hydroxypropyl (meth)allyl ether, 2-
Hydroquine propyl (meth)allyl ether, 4-hydroxybutyl (meth)allyl ether, 3-hydroxybutyl (meth)allyl ether, 2-hydroxy-2-
Hydroxyl group-containing allyl ethers such as methylpropyl (meth)allyl ether, 5-hydroxypentyl (meth)allyl ether or 6-hydroxyhexyl (meth)allyl ether; addition reaction of these various allyl ethers with ε-caprolactone Product; 2-hydroxyethyl (meth)acrylate, 2-hydroquinpropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4 - Hydroxyl group-containing (meth)acrylates such as hydroxybutyl (meth)acrylate, polyethylene glycol mono(meth)acrylate or polypropylene glycol mono(meth)acrylate; or addition of various (meth)acrylates listed above with ε-caprolactone Main reaction components, etc.

Examples of the other copolymerizable monomer (a-3) include methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, and imbutyl. Vinyl ether, tert-butyl vinyl ether, n-pentyl vinyl ether, n-hexyl vinyl ether, n-octyl vinyl ether,
Alkyl vinyl ethers or substituted alkyl vinyl ethers such as 2-ethylhexyl vinyl ether, chloromethyl vinyl ether, chloroethyl vinyl ether, benzyl vinyl ether or phenylethyl vinyl ether; cycloalkyl vinyl ethers such as cyclopentyl vinyl ether, cyclopentyl vinyl ether, methyl cyclohexyl vinyl ether;
Vinyl-2,2-dimethylpropanoate, vinyl-2
, 2-dimethylbutanoate, vinyl-2,2-dimethylpentanoate, vinyl-2,2-dimethylhexanoate, vinyl-2-ethyl-2methylbutanoate,
Vinyl-2-ethyl-2methylpentanoate, vinyl-3-chloro 2,2-dimethylpropanoate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl caproate, vinyl caprylate, capric acid Vinyl, vinyl laurate, C9 aliphatic vinyl carboxylate, C1O branched aliphatic vinyl carboxylate, C
1l branched aliphatic vinyl carboxylate or vinyl aliphatic carboxylate such as vinyl stearate; vinyl cyclohexanecarboxylate, vinyl methylcyclohexanecarboxylate, vinyl benzoate or vinyl p-tert-butylbenzoate. , vinyl esters of carboxylic acids having a cyclic structure; acrylic esters such as methyl acrylate, ethyl acrylate, butyl acrylate or cyclohexyl acrylate; such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate or benzyl methacrylate Methacrylic acid esters; α-olefins such as ethylene, propylene or butene-1; various halogenated olefins excluding fluoroolefins such as vinyl chloride or vinylidene chloride;
Aliphatic vinyl compounds such as styrene, α-methylstyrene or vinyltoluene; vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinylmethyljethoxysilane, vinyltris(
β-methoxyethoxy) silane, allyltrimethoxysilane, trimethoxysilylethyl vinyl ether, triethquinsilylethyl vinyl ether, methyldimethoxysilylethyl vinyl ether, trimethoxysilylpropyl vinyl ether, triethoxysilylpropyl vinyl ether, methyljethoxysilylpropyl vinyl ether, Monomers containing hydrolyzable silyl groups such as γ-(meth)acryloyloxypropyltrimethoxysilane, γ(meth)acryloyloxypropyltriethoxysilane or γ-(meth)acryloyloxypropylmethyldimethoxysilane; N- Amino group-containing amide unsaturated monomers such as dimethylaminoethyl (meth)acrylamide, N-diethylaminoethyl (meth)acrylamide, N-dimethylaminopropyl (meth)acrylamide or N-diethylaminepropyl (meth)acrylamide; dimethylamino Ethyl (meth)
acrylate or dialkylaminoalkyl (meth)acrylates such as diethylaminoethyl (meth)acrylate; tert-butylaminoethyl (meth)acrylate, tert-butylaminopropyl (meth)acrylate, aziridinylethyl (meth)acrylate, Amine group-containing monomers such as pyrrolidinylethyl (meth)acrylate or piperidinylethyl (meth)acrylate; or carboxyl group-containing monomers such as (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid or fumaric acid. Quantities, etc.

From the viewpoint of increasing the polymerization yield of the fluorine-containing vinyl polymer (A) itself, it is desirable to use alkyl vinyl ethers, cycloalkyl vinyl ethers, hydroxyl group-containing vinyl ethers, and carboxylic acid vinyl esters, Further, the type and amount of the monomer to be used may be determined as appropriate from the viewpoint of coating workability and coating performance such as weather resistance.

To prepare the fluorine-containing vinyl polymer (A) component, using a radical polymerization initiator, emulsion polymerization, suspension polymerization,
The polymerization reaction may be carried out by making full use of known techniques such as bulk polymerization or solution polymerization. Examples of such radical polymerization initiators include diacyl peroxides such as acetyl peroxide or benzoyl peroxide; methyl ethyl ketone peroxide or cyclohexanone peroxide. Ketone peroxides such as hydrogen peroxide, t-butyl hydroperoxide or cumene hydroperoxide; dialkyl peroxides such as di-t-butyl peroxide or dicumyl peroxide;
Alkyl peroxy esters such as t-butylperoxyacetate or t-butylperoxybivalate; azo compounds such as azobisisobutyronitrile or azobisisovaleronitrile; or potassium persulfate or ammonium persulfate. Particularly representative are persulfates.

As the polymerization reaction method, there are various known methods as described above, but among these, bulk polymerization and solution polymerization are preferable.Furthermore, it is preferable to use the resulting copolymer as it is, for example, in a solution-type paint. From the standpoint of being usable as a resin composition for use, solution polymerization is particularly desirable.

Typical solvents used in preparing the fluorine-containing vinyl polymer by the solution polymerization method include:
Aromatic hydrocarbons such as benzene, toluene or xylene; aliphatic hydrocarbons such as n-pentane, n-hexane or n-octane; such as cyclopentane, cyclohexane, methylcyclohexane or ethylcyclohexane Alicyclic hydrocarbons; mixed hydrocarbons such as mineral spirits; methanol, ethanol, n-
Propertool, Impropertool, n-butanol, isobutanol, t-butanol, n-pentanol,
Alcohols such as impentanol, n-hexanol, n-octatool, 2-ethylhexanol, cyclohexanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether or propylene glycol monoethyl ether dimethoxyethane, tetrahydrofuran, dioxane, diisopropyl ether or di-
Ethers such as n-butyl ether; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, methyl amyl ketone, cyclohexanone or isophorone; methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-propyl acetate, acetic acid Esters such as isopropyl, n-butyl acetate, isobutyl acetate, amyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate or ethylene glycol monobutyl ether acetate; or chloroform, methylene chloride, carbon tetrachloride, trichloroethane or tetra These include chlorinated hydrocarbons such as chloroethane, as well as N-methylpyrrolidone, dimethylformamide, dimethylacetamide, or ethylene carbonate.

These organic solvents may be used alone or in combination of two or more.

In order to prepare the fluorine-containing vinyl polymer (A) from the various monomer components listed above by a solution polymerization method, all monomers, a polymerization initiator, and a solvent are charged in a reactor at once and polymerized. Alternatively, monomers other than the fluorine-containing vinyl monomers and a polymerization initiator are added continuously or in portions to a reactor containing the fluorine-containing vinyl monomers and a solvent. Furthermore, a method can be applied in which all monomers and a polymerization initiator are added continuously or in portions to a reactor containing only a solvent.

The above description has focused on solvent-soluble fluorine-containing vinyl polymers, but of course, the polymers may also be in the form of so-called non-aqueous dispersions, which are dispersed in solvents, or partially It may also contain particles that have been gelled.

Next, an isocyanurate ring-containing isocyanate compound (
B) will be explained, but the isocyanate compound (
Particularly representative diisocyanate compounds as essential raw material components in B) include 1,4-tetramethylene diisocyanate and 1.4-tetramethylene diisocyanate. Alkylene diisocyanates having 2 to 8 carbon atoms such as 6-hexamethylene diisocyanate; 1,3- or 1,4-diisocyanate cyclohexane, 1,3- or 1,4-bis(isocyanate methyl)-cyclohexane Cycloalkylene diisocyanates having 6 to 8 carbon atoms such as; 1,
Aralkylene diisocyanates having 7 to 8 carbon atoms such as 3- or 1,4-xylylene diisocyanate; or 2゜2.4- or 2,4.4-trimethylhexamethylene diisocyanate, impropylidene-
bis(4-cyclohexyl isocyanate) or 3
Examples include diisocyanate compounds having 9 or more carbon atoms, such as methyl-isocyanate-3,5,5-trimethylcyclohexyl isocyanate, and mixtures thereof.

Note that the use of a diisocyanate compound having 9 or more carbon atoms is undesirable from the standpoint of resin design, as it undesirably lowers the isocyanate content of the isocyanurate ring-containing polyisocyanate derived therefrom, and is also economically undesirable from a practical standpoint. Because it is impossible to avoid the disadvantages of
It is desirable that the amount used be kept at 50% or less, preferably 30% or less.

The diol, which is the other raw material component of the isocyanate compound (B) of the present invention, usually has 10 to 10 carbon atoms.
40, preferably this is 1
2 to 30.

If the carbon number of the diol is less than 10, the flexibility of the coating film obtained from the top coating of the present invention tends to decrease,
On the other hand, when it exceeds 40, the isocyanate compound (B
) is undesirable because it unnecessarily lowers the isocyanate content.

Such carbon number used in the method of the present invention is 10
The diol of ˜40 usually has an alkylene chain or a cycloalkylene chain, and may have a substituent such as a hydrocarbon group.

Particularly representative of such diols are 1.10
-Decanediol, 1,12-dodecanediol, 2-
Dimeric hydrogenated product of hydroxybalmityl alcohol, 2-hydroxystearyl alcohol, 12-hydroxystearyl alcohol, oleyl alcohol, or 2,2-bis(4-hydroxycyclohexyl)propane (commonly known as hydrogenated bisphenol A) or a mixture thereof.

It goes without saying that the mixing or combined use of small amounts of monoalcohols, triols, etc. with these diols is permissible as long as the properties of the isocyanate compound (B) are not significantly impaired.

The isocyanurate ring-containing isocyanate compound (B
), the diols listed above are
1 to 40% of the total weight of diisocyanate,
Preferably, it is used in a range of 2 to 30%.

Furthermore, as the above-mentioned isocyanurate catalyst, it is appropriate to use a compound that has a low electron density and contains atoms (groups) with strong cationic properties, and among these, particularly representative ones include N, N, , N-trimethyl-2-hydroxypropylammonium tN+laterbutyl benzoate [I], sodium ethylate or sodium propionate, and in particular, the following formula (1,)CH.

CH.

The use of the catalyst of the form shown is suitable for producing the isocyanate compound (B) because it is easy to purify.

Note that the catalyst is usually prepared as a diluted solution with an organic solvent.
10 to 1100 pp per diisocyanate compound,
Preferably, an amount within the range of 20 to 500 ppm is used.

In this way, the isocyanurate ring-containing isocyanate compound (B) used in the present invention is obtained.

Furthermore, this isocyanate compound (B) also includes a blocked isocyanate compound obtained by reacting the polyisocyanate obtained by the above method with a compound as shown below, which is generally known as a blocking agent. Included.

Among such blocking agents, only representative ones include chioxime compounds such as methyl ethyl ketone oxime or methyl isobutyl ketone oxime; lactam compounds such as δ-cafrolactam; amide compounds such as acetanilide or octylic acid anilide;
Alternatively, various compounds having so-called active hydrogen atoms, such as alcohols such as isopropyl alcohol or n-butyl alcohol; Furthermore, compounds that generate active hydrogen atoms due to tautomerism, such as acetylacetone and ethyl acetoacetate, can also be used as blocks. Examples of agents include:

Isocyanate compounds other than the isocyanate compound (B) can be used in the top coat in the method of the present invention, if necessary.

Examples of particularly representative isocyanate compounds other than the isocyanate compound (B) include aliphatic diisocyanates such as hexamethylene diisonanate or trimethylhexamethylene diisocyanate; Cycloaliphatic diisocyanates such as; or organic diisocyanate compounds such as aromatic diisocyanates such as tolylene diisocyanate or 4,4'-diphenylmethane diisocyanate;
Polyester polyols) or adducts with water, furthermore, polymers of organic diisocyanate compounds as listed above (including isocyanurate type polyisocyanate compounds), isocyanate biuret compounds, etc. Representative examples of blocked isocyanate compounds include those obtained by blocking the various isocyanate compounds listed above with known and commonly used blocking agents.

To prepare the desired top coat using the hydroxyl group-containing fluorine-containing vinyl polymer (A), which is an essential component of the top coat, and the isocyanate compound (B), these are prepared in accordance with a conventional method. Simply mix both components.

The blending ratio of these isocyanate compounds (B) and the fluorine-containing vinyl polymer (A) is OH/NC0.
=0.5 to 2.0 (equivalence ratio) is preferable from the viewpoint of coating film performance.

That is, the number of NC○ groups is 0, 5 for 1 equivalent of hydroxyl group.
If the amount is less than 1, it is difficult to obtain a sufficient coating film performance, and if the number of NC○ groups exceeds 2°0 per equivalent of hydroxyl group, the coating film tends to become brittle and easily colored. Undesirable.

In addition, when preparing a top coat using the above-mentioned fluorine-containing vinyl polymer (A) and isocyanate compound (B), a known and commonly used curing catalyst can be used as necessary. .

Particularly representative curing catalysts include various organometallic compounds such as dibutyltin dilaurate, dibutyltin diacetate, silver dioctylate or cobalt naphthenate;
or 1,4-diazabicyclo-(2,2,2)-octane or 1,8-diazabicyclo-(5,4,0)
- There are various amine compounds such as undecene-7.

Additionally, colored pigments and/or metal powders can be used if necessary.

Furthermore, as necessary, various resins and solvents, fluidity regulators, color separation inhibitors, antioxidants, ultraviolet absorbers,
It goes without saying that various known and commonly used additives such as light stabilizers or silane coupling agents can be added.

Typical examples of the various resins mentioned above include cellulose resins such as nitrocellulose or cellulose acetate butyrate, vinyl chloride/vinyl acetate copolymer resins,
Examples include ketone resins, petroleum resins, acrylic polymers, oil-free alkyd resins, alkyd resins, and epoxy resins, and acrylic resins are particularly suitable from the viewpoint of compatibility.

As the solvents, the same various solvents as those used in preparing the fluorine-containing vinyl polymer (A) described above, and mixtures thereof can be used.

Coating in the method of the present invention is carried out in the same manner as conventional methods using the above-mentioned undercoat and topcoat.

That is, an undercoat is adjusted to a predetermined viscosity on an object that has been surface-treated or, if necessary, coated with a primer or surfacer, etc., and then a dry film thickness of 5-5 is applied to the object.
Paint to a thickness of 40 μm.

Next, the top coat paint is adjusted to a predetermined viscosity and applied so that the dry film thickness becomes 5 to 60 μm.

As a method for coating both the undercoat paint and the topcoat paint, a conventional method such as roll coater air spray, airless spray, or electrostatic coating may be used.

In the present invention, the top coat may be applied while the undercoat is in an uncured state, or may be applied while the undercoat is in a cured state.

After painting, store at room temperature for 3 days or at 60-300°C.
A cured coating film can be obtained by drying at a temperature of about several seconds to about 60 minutes.

However, when a blocked isocyanate compound is used, it is dried at a temperature of 140°C or higher.

〔Example〕

Next, the present invention will be specifically explained using reference examples, examples, applied examples, and comparative applied examples.
All parts and percentages are by weight unless otherwise specified.

Reference Example 1 [Preparation example of fluorine-containing vinyl polymer (A)] 390 parts of vinyl p-tert-butylbenzoate was placed in a 2-liter stainless steel autoclave that was sufficiently purged with nitrogen. 1.00 parts of C9 (vinyl ester of branched aliphatic carboxylic acid, manufactured by Shell), 110 parts of 4-hydroxybutyl vinyl ether, 430 parts of n-butyl acetate, and azobisinvaleronitrile (ABNV). Part 15, tert-
10 parts of butyl peroxyoctoate (TBPO) and 3 parts of 1,2°2.6.6-pentamethylpiperidine
I prepared a section.

Then, 4 of the liquefied and collected chlorotrifluoroethylene
00 parts were compressed and reacted at 60°C for 15 hours with stirring, and when the non-volatile content (NV) reached 67%, it was cooled to room temperature and 318 parts of xylene was added, and the NV was 55%.
A solution of the desired copolymer was obtained. Hereinafter, this will be abbreviated as A-1.

Reference Example 2 (same as above) NV was made in the same manner as in Reference Example 1, except that the monomer composition was changed to: When it reached 68%, it was cooled to room temperature and 60 parts of xylene was added to obtain a solution of the desired copolymer with an NV of 55%.Hereinafter, this will be abbreviated as A-2.

Reference Example 3 (same as above) Monomer composition: cyclohexyl vinyl ether 160 parts ethyl vinyl ether 200 parts 4-hydroxybutyl
1501/Vinyl ether chlorotrifluoroethylene The procedure was repeated in the same manner as in Reference Example 1 except that 49011 was used, and when the NV reached 68%, the mixture was cooled to room temperature and 346 parts of xylene was added to achieve a NV of 55%. A polymer solution was obtained. Below, this is A
It is abbreviated as -3.

Reference Example 4 [Example of Preparation of Isocyanate Compound (B)] A container equipped with a stirrer, a nitrogen gas introduction tube, an air cooling tube, and a thermometer.
3.50 ml of "Desmodur H" (hexamethylene diisocyanate, manufactured by Bayer AG, West Germany) was placed in a 5-liter glass four-piece flask under a nitrogen gas atmosphere.
0g and "Crosanol" (manufactured by Henkel, West Germany, 12-hydroxystearyl alcohol; purity approximately 8
0%) was charged.

Next, the flask was placed in an oil bath and the temperature was raised to 65°C without stirring, so that the contents of the flask became a homogeneous liquid.

Subsequently, the temperature was maintained at the same temperature for 2 hours, and then the temperature was lowered to 55°C.

As an isocyanuration catalyst, 3.4 g of a 20% butyl cellosolve solution of N,N,N-trimethyl-N-2-hydroxypropyl alumonium balatasharybutyl benzoate represented by the above formula CI) was added in portions, After a subsequent reaction at a temperature of 60°C for 3 hours, a 7% xylene solution of monochloroacetic acid was added.3.
4 g was added to deactivate the isocyanurate catalyst, and the isocyanurate reaction was completed.

After cooling the reaction mixture to room temperature, 1,000 g of it was subjected to molecular distillation to obtain 549.4 g (conversion rate 55.0%) of an isocyanate compound having an isocyanurate ring as a distillation residue and hexamethylene diisocyanate as a distillate. 450.0 g (recovery rate: 45.0%) of this product was obtained.

The obtained isocyanurate ring-containing isocyanate compound was diluted with xylene to a concentration of 80% to obtain 687.2 g of a transparent isocyanate compound solution.

The isocyanate compound solution thus obtained had an isocyanate content of 11.9%. Below, this is B
Reference Example 5 (same as above), abbreviated as -1, instead of hexamethylene diisocyanate as a diisocyanate compound, 3,290 g of hexamethylene diisocyanate and 210 g of "Takene" 500J (xylylene diisocyanate manufactured by Takeda Pharmaceutical Co., Ltd.) were used, 4 of the same isocyanurate catalyst solution as Reference Example 4.
The isocyanurate reaction was carried out in the same manner as in Reference Example 4 except that 7 g was used.
．． 219g was obtained.

1,003 g of the resulting reaction mixture was subjected to molecular distillation, and the distillation residue was 522 g of isocyanurate ring-containing isocyanate compounds (cyclization rate 52.1%, distillate 480 g, recovery rate 47°9%). I got it.

Then, the obtained isocyanate compound was diluted with xylene.
The solution was diluted to a concentration of 5% to obtain 696 g of a transparent isocyanate compound solution.

The isocyanate compound solution thus obtained had an isocyanate content of 10.3%. Below, this is B
It is abbreviated as -2.

Reference Example 6 (same as above) The reaction was carried out in the same manner as in Reference Example 5, except that isophorone diisonanate (manufactured by Huels, USA) was used instead of xylylene diisocyanate as the diisocyanate compound. ,2
18g was obtained.

1,000 g of the obtained reaction mixture was subjected to molecular distillation, and the distillation residue was 532.5 g of isocyanurate ring-containing isocyanate compound (conversion rate 53.3%).
I got it.

Then, the obtained isocyanate compound was diluted with xylene.
Diluted to a concentration of 5% to obtain 707 g of a transparent isocyanate compound solution.

The polyisocyanate solution thus obtained had an isocyanate content of 11.0%. Below, this will be referred to as B-
It is abbreviated as 3.

Reference Example 7 (same as above) Instead of hexamethylene diisocyanate as a diisocyanate compound, 2,100 g of hexamethylene diisocyanate, 1 of rTakenate 600J (1,3-bis(isocyanate methyl)-cyclohexane manufactured by Shikinichi Yakuhin Co., Ltd.)゜400g was used, except that 3.9g of the same isocyanurate catalyst liquid as in Reference Example 4 was used.
The isocyanurate reaction was carried out in the same manner as in Reference Example 4 to obtain 4,215 g of a reaction mixture in which the catalyst had expired.

1,001 g of the obtained reaction mixture was subjected to molecular distillation, and the distillation residue was 541.7 g of isocyanurate ring-containing isocyanate compound (conversion rate 54.2%).
I got it.

Then, the obtained isocyanate compound was diluted with xylene.
Diluted to 5% concentration to obtain 722.3 g of a transparent isocyanate compound solution.

The isocyanate compound solution thus obtained had an isocyanate content of 10.7%. Below, this is B
It is abbreviated as -4.

Reference Example 8 (same as above) Using the same reaction apparatus as Reference Example 4, "Takenate 600"
using 3,500 g of 12-hydroxystearyl alcohol and 6.6 g of the catalyst solution of Reference Example 1.
The reaction mixture was treated in the same manner as in Reference Example 4, except that the isocyanurate reaction was carried out at 70°C, to obtain 3°750 g of a reaction mixture in which the catalyst had expired.

1,001 g of the resulting reaction mixture was subjected to molecular distillation to yield 401.7 g of an isocyanate compound having an isocyanurate ring as a distillation residue (conversion rate 49.2%).
) was obtained. The isocyanate content of the isocyanate compound was 17.1%.

Next, 195 g of this isocyanate compound, 77 g of methyl ketoxime, 50 g of xylene, and 40 g of cellosolve acetate were charged into a 500 ml glass flask equipped with a stirrer, a thermometer, a nitrogen gas inlet tube, and an exhaust port, and then urethane was added. Add 5.0 g of dibutyltin diacetate as a reaction catalyst and
After raising the temperature to 0°C and maintaining the same temperature for 3.5 hours, it was confirmed by chemical analysis that no unreacted isocyanate groups were present, and the reaction was terminated.

The target blocked isocyanate compound thus obtained is a viscous liquid with an NV of 75° and 4%, and
The effective isocyanate content was 9.3χ. below,
This is abbreviated as B-5.

Reference Example 9 (Example of Preparation of Undercoat Paint) The following proportions were mixed according to the usual paint manufacturing method, and mixed with a diluting solvent in Ford cup Nn4 from 11 to
The viscosity was adjusted to 12 seconds and used as an undercoat.

"Pesocolite 57-1054J [hydroxyl-containing polyester resin manufactured by Inu Nippon Ink Chemical Industry Co., Ltd.; non-volatile content 70%]""Super Beckamine L-117-60J (same company f
f n-butylated melamine resin; non-volatile content 60%) rcAB-381-0,5J (cellulose acetate butyrate manufactured by Eastman Kodak, USA) 72 parts 42 parts 25 parts rEPOLEN N-10J (manufactured by the same company) Alpaste 1860YLJ [Aluminum paste manufactured by Toyo Aluminum Co., Ltd.; non-volatile content 65%] 15 parts 23 parts 177 parts or less The paint thus obtained is abbreviated as BC-1.

Reference Example 10 (Same as above) A paint compounded according to a normal paint manufacturing method in the following proportions was diluted with a diluting solvent in Ford Cup No. 4.
The viscosity was adjusted so that it lasted for 3 to 14 seconds, and an undercoat paint was prepared.

[Acridic 47-7124 (Hydroxy group-containing acrylic resin manufactured by Dainippon Ink and Chemicals Co., Ltd.; nonvolatile content 50%)] [Super Beckamine L-117-60J 160 parts 33 parts "Alpaste 1860YLJ [First Gen Blue NKJ [Dog] Cyanine Blue manufactured by Nippon Ink Chemical Industry Co., Ltd.] 23 parts 2 parts 218 parts or less, the paint thus obtained is abbreviated as BC-20 Reference Example 11 (Same as above) The compounded material according to the paint manufacturing method is diluted with Ford Cup Na4 using a diluting solvent.
The viscosity was adjusted to ~12 seconds and used as an undercoat paint.

"Acridic 47-567" [Hydroxyl group-containing acrylic resin manufactured by Dainippon Ink and Chemicals Co., Ltd.; non-volatile content 50%] "Parnock DN-950J (100 parts and 18 parts of polyisocyanate compound manufactured by the same company; non-volatile content 75%) ) “Tie Bake CR-93J 60 copies [
Titanium oxide 3 manufactured by Ishihara Sangyo Co., Ltd. 1 8 parts or less, this paint is abbreviated as BC-4.

Reference Examples 12 to 16 and Comparative Reference Examples 1 to 3 (Preparation Example of Top Coating Paint) Using the fluorine-containing vinyl polymers obtained in Reference Examples 1 to 3 and the isocyanate compounds obtained in Reference Examples 4 to 8, ,
Various top coats were prepared according to the formulations shown in Table 1, and xylene/[Tsurpetz 100J (petroleum solvent manufactured by Exxon, USA)/butyl acetate/cellosolve acetate = 40/20/20/20 (mixed by weight) ratio)
It was diluted to 23 seconds with Ford Cup N004 using a mixed solvent.

For comparison purposes, conventional fluorine-containing resin topcoat paints and acrylic resin topcoat paints were also prepared in the same manner.

Footnotes to Table 1 1) Isocyanate compounds manufactured by Nippon Polyurethane Industries, Ltd. Note 2) Blocked isocyanate compounds manufactured by the same company Note 3) Isocyanate compounds manufactured by Dainippon Ink Chemical Co., Ltd. Note 4) Dainippon Ink Hydroxyl group-containing acrylic resin manufactured by Kagaku Kogyo Co., Ltd. Note 5) Butylated melamine resin manufactured by the same company Note 6) Ultraviolet absorber manufactured by Ciba Geigy of Switzerland Note 7) Light stabilizer manufactured by the same company Examples 1 to 5 and Comparative Examples 1 to 3 A cationic electrodeposited coating and a polyester melamine surfacer were applied to a mild steel plate, and then an undercoat as shown in Table 2 was applied using air spray so that the dry film thickness was 20 μm. did.

Next, after setting for 5 minutes, a top coat was applied by air spray so that the dry film thickness was 35 μm. After leaving it at room temperature for 20 minutes,
The bake was allowed to dry for 30 minutes at °C.

A coating film performance test was conducted using each test piece thus obtained. The results are summarized in the same table.

〔Effect of the invention〕

As described above, according to the method of the present invention, it is possible to provide a novel coating method that uses a top coat that has extremely excellent long-term weather resistance and is also resistant to acid and scratches. Of course, by applying and curing a top coat that contains a specific fluorine-containing polymer and a specific isocyanate compound as essential components, it is possible to achieve extremely high scratch resistance as well as chemical resistance. It is also possible to provide an extremely novel and useful coating method that provides a coated product with excellent properties, particularly acid resistance and weather resistance.

Claims (1)

[Scope of Claims] 1. A fluorine-containing vinyl polymer (A) containing an average of at least two hydroxyl groups in one molecule, and a diisocyanate on a substrate on which a coating film of an undercoat is formed. Painting a top coat comprising as an essential component an isocyanate compound (B) having an isocyanurate ring obtained by reacting the compound and a diol having 10 to 40 carbon atoms in the presence of an isocyanurate catalyst. A method of painting consisting of applying pressure. 2. The fluorine-containing vinyl polymer (A) described above contains 15 to 75% by weight of the fluorine-containing vinyl monomer (a-1) and 5 to 40% by weight of the hydroxyl group-containing vinyl monomer (a-2). The coating method according to claim 1, which is obtained by copolymerizing 5 to 85% by weight of the other copolymerizable monomer (a-3). 3. The above-mentioned fluorine-containing vinyl monomer (a-1) is tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, vinyl fluoride, vinylidene fluoride, an alkyl group having 1 to 18 carbon atoms (per ) fluoroalkyl vinyl ether, and (per)fluoroalkyl trifluorovinyl ether in which the alkyl group has 1 to 18 carbon atoms.
The coating method according to claim 1 or 2, wherein the coating method is of seeds. 4. The other copolymerizable monomer (a-3) described above is
The coating method according to claim 1 or 2, wherein the coating method is at least one selected from the group consisting of alkyl vinyl ethers, cycloalkyl vinyl ethers, and carboxylic acid vinyl esters. 5. The isocyanate compound (B) having an isocyanurate ring described above is composed of an alkylene diisocyanate having 2 to 8 carbon atoms, a cycloalkylene diisocyanate having 6 to 8 carbon atoms, and an aralkylene diisocyanate having 7 to 8 carbon atoms. The coating method according to claim 1, which is obtained by reacting a diisocyanate selected from the group with a diol having 10 to 40 carbon atoms in the presence of an isocyanurate catalyst.