JPS6092365A - Wet-on-wet overcoating clear paint composition - Google Patents

Abstract

PURPOSE:To provide a paint which is poorly miscible with a base coat and can be thickly coated in one stage, by blending a film forming acrylic polymer contg. functional groups, a volatile org. soln. diluent, a crosslinking agent and a finely divided crosslinked polymer particle. CONSTITUTION:A paint consists of a film forming acrylic polymer (a) contg. functional groups reactive with a crosslinking agent described below, a volatile org. soln. diluent (b) carrying said polymer, a crosslinking agent (c) dissolved in said diluent, and a finely divided crosslinked polymer particle (d) having a particle size of 0.01-10mu which is insoluble in a mixture of the polymer (a), the diluent (b) and the crosslinking agent (c) and is stably dispersed therein in such a proportion that the quantity of said crosslinked polymer particle (d) accounts for 0.2-20wt% of the combined quantity (on a solid basis) of the polymer (a), the crosslinking agent (c) and the crosslinked polymer particle (d).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a clear top coat composition that is applied onto a base coat by a wet-on-wet method.

For example, as a coating method for the surface of an automobile body, a method is widely practiced in which a wet-on-wet clear top coat is applied onto a coating containing colored pigments and/or metallic pigments, and the coating is simultaneously baked or cured at room temperature.

This coating method provides an excellent finish - excellent appearance, high durability,
It is particularly suitable for automobile line painting as a method for efficiently obtaining high-quality coating films with high solvent resistance, high chemical resistance, and high ffi/I colorfastness.

In order to achieve high appearance quality with this method, the combination of the base coat paint and the clear top coat paint is important. In other words, when the base coat and clear top coat are mixed, the metallic pigment particles in the base coat This is because the finish may be poor due to poor alignment or loss of gloss.

For this reason, conventional methods have been to increase the molecular weight of the resin for the hate coat, or use different types of resins for the base coat and top coat.
For example, when acrylic resin is used as the resin for Tosopko 1~, methods are used to reduce the base coat and top coat by replacing or blending it with polyester or cellulose acetate butyrate as the base coat resin. . In addition, methods for reducing miscibility by changing coating conditions include applying the base coat in two coats, lengthening the length of the base coat and l-tub coat, and increasing the viscosity of the base coat.

] Both of the methods described in item 1 have drawbacks. In other words, the method of increasing the molecular weight of the resin for Hesco-1 is that spraying reduces the amount of non-volatile matter, and when using a different type of resin, the adhesion between the base coat and the Cree-1 coat decreases. death,
Furthermore, changing the coating conditions increases the number of required steps and reduces work efficiency.

The methods described in -1- are all... :This is a countermeasure for the 1-1 side. In contrast, the present invention proposes a method of reducing miscibility with the base coat by improving the clear coat side. The present invention not only achieves the objective of reducing miscibility with the base coat, but also allows for thicker coating of the clear coat. One way to improve the high-quality appearance achieved by the two-coat system is to apply a thick layer of L-Tsubukurire. For example, in a two-coat Mechlink coating using aluminum powder, there is approximately 10 to 50 tt of aluminum powder in the base coat composition, and there are parts that protrude from the base coat surface, so the top clear coating composition If they are not completely covered, they will exhibit the so-called flickering appearance well known in the art, resulting in poor quality. In particular, when trying to increase the particle size of aluminum powder to increase glitter and create a metallic feel, this drawback becomes noticeable and a thick coating of top clear is required. However, conventional top clear coating has mainly been carried out in one stage, and it has not been possible to apply a sufficiently thick coating due to the sagging performance of the top clear coating composition. In other words, with conventional top clear coating compositions, the coating thickness of 20 to 30 microns was the limit for a single coating of Tonobu Clear. If one stage is replaced by two or more stages, thick coating is possible, but this increases the number of steps, lowers productivity, and requires modification of the existing line, making it difficult to implement.

The present inventors have developed a clear top coat composition that is applied onto a base coat using a wet-on-wet method.
It has been found that by using crosslinked polymer fine particles, it is possible to reduce miscibility with the base coat and provide a composition that can be coated thickly in one stage.

According to the present invention, (al) a film-forming acrylic polymer having a functional group capable of reacting with a crosslinking agent; (C) a volatile organic liquid diluent carrying the polymer; (C) in the organic liquid diluent; a crosslinking agent dissolved in
(dl The above polymer (al, diluent fbl, crosslinking agent fc
The crosslinked polymer fine particles 7- (di is: The polymer (al), the crosslinking agent tc+, and the crosslinked polymer (C1
There is provided a wet-on-wet furnace clear coating composition, characterized in that C is contained in an amount of 0.2 to 20% by weight based on the total solid weight of the composition.

According to the present invention, the crosslinked polymer fine particles (hereinafter referred to as microgel j) are added to the composition for the top clear coat 1.
By the presence of , it is possible to coat thickly while maintaining durability, solvent resistance, and chemical resistance, and to suppress miscibility with the base coat composition. Structural viscosity develops due to the presence of microgels, and when shearing force is applied during spray coating, etc., this structure is lost and the coating can be applied without adversely affecting atomization, and as soon as the coating is applied, the structural viscosity is restored and the viscosity increases. This is because it does not cause sagging and transfers easily to the base coat composition.

Furthermore, in a cured film, volume shrinkage occurs, making it difficult to obtain plump skin, or what is known in the industry as a fleshy feeling, but in the case of the clear paint composition of the present invention, the addition of microgels provides a fleshy feeling. and improves the appearance of the paint film.

Furthermore, in recent years, due to requests for resource conservation and pollution control, the use of high-solid and 7-metal paints without reducing the amount of solvent in paints has been attracting attention. Enables high solids without adversely affecting sex. When converting a solution-type paint in which the film-forming resin is dissolved in a diluted solvent to a high solids, the common method is to lower the molecular weight of the film-forming resin to lower the viscosity and increase the non-volatile content of the coating. However, as a result, the viscosity of the coating upon application is lower than that of conventional coatings, resulting in a drawback that it is prone to sagging. When the clear coat composition is made into a high solid by this method, the viscosity of the coating composition during coating is low and it moves easily, increasing its permeability into the HESCO 1 composition. there were. According to the present invention, high solidity can be achieved without causing these drawbacks by adding microgel instead of reducing the molecular weight.

The film-forming acrylic polymer used in the present invention (Jll is generally known) having a functional group capable of reacting with a crosslinking agent. Protective properties required as a clear top coat, such as crank, whitening,
It must exhibit weather resistance, solvent resistance, chemical resistance, impact resistance, etc. against peeling and loss of gloss, and it must also have excellent decorative functions. Therefore, the acid value is usually between 0.5 and 40.
° Preferably 2 to 30, hydroxyl value 40 to 200. It is preferably 50 to 150. If the acid value or hydroxyl value is too low, the crosslinking density will be low and the strength of the coating film will be insufficient, while if it is too high, the water resistance will be insufficient, causing blistering and whitening.

Polymer (al is a compound having an alkyl ester of acrylic acid or methacrylic acid, optionally another ethylenically unsaturated monomer that can be copolymerized with it, and a functional group that can react with a crosslinking agent) It can be obtained by copolymerizing by a conventional method.

Examples of suitable (meth)acrylic acid alkyl esters include:
Includes methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate.

Examples of other ethylenically unsaturated monomers include vinyl acetate, acrylonitrile, styrene and vinyltoluene.

Examples of monomers having functional groups that can react with crosslinking agents include acrylic acid, methacrylic acid, 2-hydroxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, N-(butoxymethyl) - (meth)acrylamide, glycidyl (meth)acrylate, etc.

Furthermore, a monomer that can act as a catalyst for the crosslinking reaction between the acrylic polymer +a) and the crosslinking agent can be incorporated into the acrylic polymer, for example, acrylic acid and methacrylic acid are usually used. Acid groups can be introduced into the polymer by using a sulfonic group-containing monomer, such as 2-sulfoethyl methacrylate or acidic butyl maleate.

The film-forming acrylic polymer (a) used in the present invention
Even if 1 is dissolved in the mixed system of organic liquid diluent fhl and crosslinking agent (C1), or even if it is stably dispersed without dissolving, a part of it will dissolve and the rest will remain in the mixture in 11. You can leave it there.

As a polymerization method, the well-known i? Ei polymerization, non-aqueous dispersion polymerization, bulk polymerization, etc. can be used, and solvent replacement from emulsion polymerization can also be used.

Examples of crosslinking agents that can be used in the present invention include known polyisocyanates, aminoplast resins, formaldehyde condensates of nitrogen-containing compounds such as urea, diourea, melamine, and henzoguanamine, and lower grades of such condensates. Examples include alkyl ethers (the number of carbon atoms in the alkyl group is 1 to 4).

The appropriate amount of the crosslinking agent is 5 to 50% by weight, preferably 10 to 40% by weight of the solid content R1 of the film-forming acrylic polymer (a) and the crosslinking agent (b).

1 The microgel fdl used in the present invention contains the film-forming acrylic polymer 4al, an organic liquid diluent (b
These are fine particles of a crosslinked polymer having a particle size of 0.01 to 10 II, which are crosslinked to a certain extent so as to be insoluble in a mixed system consisting of fcl and a crosslinking agent fcl.

Conventional methods for producing such microgels include, for example,
A fine particle copolymer is produced by emulsion polymerizing the ethylenically unsaturated monomer with a crosslinked 171° comonomer in an aqueous medium, and water is removed by solvent displacement, azeotropy, centrifugation, filtration, drying, etc. copolymerization of an ethylenically unsaturated monomer and a crosslinkable comonomer in the presence of a stabilizer in a nonaqueous organic solvent that dissolves monomers such as aliphatic hydrocarbons but does not dissolve the polymer; A method called the NAD method for obtaining a dispersion of a fine particle copolymer by conducting a condensation reaction or a condensation reaction is known, but the method is not limited to the specific manufacturing method for the microgel L1 used in the present invention. This microgel is 0.01 to 10/!
The colloidal size ranges from 0.02 to 5μ.
It is desirable that the particle size is .

The blending amount of this microgel is the film-forming acrylic polymer (al), the crosslinking agent (C), and the microgel (
It accounts for 0.5 to 20% by weight, preferably 1 to 15% by weight of the total solid content of dl. If the amount of microgel is too small, the clear composition tends to sag and permeates into the base coat composition, making it impossible to achieve the intended purpose. On the other hand, if the amount is too large, the smoothness of the film will be impaired, making it impossible to obtain a high-quality finished appearance.

The organic liquid diluent (1)) used in the present invention can be any organic liquid or G; one-liquid mixture, such as a fatty acid such as hexane, heptane, etc., which is commonly used as a solvent for polymers in conventional coating compositions. group hydrocarbons, aromatic hydrocarbons such as toluene or xylene, petroleum fractions of various boiling point ranges consisting mainly of aliphatic hydrocarbons but containing some aromatic hydrocarbons, butyl acetate, ethylene glycol diacetate, 2- esters such as ethoxyethylaritate, ketones such as acetone and methyl isobutyl ketone, and alcohols such as butyl alcohol. Of course, these should be appropriately selected depending on the type of film-forming polymer (al) or the form of supporting the polymer ta+ in the diluent ibl, that is, whether it is in the form of a solution or a dispersion. When a polyisocyanate compound is used as the crosslinking agent (C1), it goes without saying that it must not have active hydrogen groups that react with it.

The composition of the present invention includes, in addition to the above (al to d+ components), other commonly used components, such as viscosity modifiers such as organic montmorillonite, polyamide, and polyethylene wax;
Silicone is also an organic polymer surface conditioning agent, ultraviolet absorber,
It can include hindered amines, hindered phenols, and the like.

Although the method for preparing the coating composition of the present invention is arbitrary, usually a varnish containing resin +81 and a diluent (BL) is prepared in advance, and the crosslinking agent FCL and microgel (DL) are added thereto and mixed well. If so, it can be prepared by adjusting the viscosity to an appropriate level with a diluent.

When polyisocyanate is used as a crosslinking agent, it should be stored in a separate container and mixed well before use.

The clear coating composition of the present invention can be applied wet-on-wet to a head coat film formed by a conventional method, and then cured at room temperature or by heating to simultaneously cure the head coat and top coat, resulting in a two-coat coating with a high finished appearance. A film can be formed.

Examples of the present invention are shown below, in which "parts" and "%" are by weight unless otherwise specified.

■Example of microgel production 1-A Notification from NAD (a) 1 match loss school 19 provisional construction.

A reaction vessel equipped with a stirrer, thermometer and reflux condenser was charged with the following raw materials: 1 methyl methacrylate.
．． 776 〃 Methacrylic acid 0.03611 Azodiisobutyroni-1-lyl 0. After purging the reaction vessel and its contents with inert gas, the temperature was raised to 100° C. and held at this temperature for 1 hour to produce a dispersed polymeric species.

After pre-mixing the following components, they were added to the reaction vessel in section 1 at a constant rate over 6 hours while heating and stirring at 100°C: Methyl methacrylate 32.459 parts Glycidyl methacrylate-1-0, 331 Meccrylic acid 0.331 Azo-diisobutyronitrile 0.203 Dimethylaminoethanol 0.070 Graph i-copolymer stabilizer solution (see below) 6.810 100.000 Contents of reaction vessel The material was held at 100'C for an additional 3 hours to remove the monomers from the insoluble polymer gel-like microparticles (1% of the total dispersion).
8-19%) and uncrosslinked polymer particles (19% of the total dispersion)
was completely converted into a dispersion containing

The Graph I copolymer stabilizer used in the above method was manufactured by the following method: 12-hydroxyste6-alinic acid with an acid value of approximately 31 to 34 mgKO■■/g (corresponding to a molecular weight of 1650 to 1800) The product was self-condensed until 100% and then reacted with an equivalent amount of glycidyl methacrylate. The resulting unsaturated polyester was mixed with a methyl methacrylate:acrylic acid (95:5) mixture in a 2:1 ratio (
(weight ratio).

(bl on board 1i1Jzu)? ＋l1JJ is shoulder A.
63.853 parts of the dispersion produced in step (al) was charged into the same reaction vessel as in the layered step fa).
It was heated to 5°C and the reaction vessel was purged with inert gas. The following ingredients were premixed and added at constant rates to the contents of the stirred reaction vessel over a period of 3 hours while maintaining the temperature at 115°C: Methyl methacrylate 3.
342 parts Hydroxyethyl acrylate 1.906 Methacrylic acid 0.496 Butyl acrylate 3.691 2-ethylhexyl acrylate 3.812 Antinone 5.712 Azodiisobutyronitrile 0.906 7 1st class - Octyl mercaptan 0.847 parts Kraft copolymer stabilizer solution (Step (see al.) 1.495 After completion of addition,
The contents of the reaction vessel were held at 115° C. for an additional 2 hours to ensure sufficient monomer conversion, and finally 13.940 parts of butyl acetate was added to bring the total to 100,00 parts. The total film-forming solids content of the dispersion thus obtained was 4
It was 5%. The content of insoluble gel polymer fine particles is 27
．． It was 0%.

The particle size was 0.08μ.

1-B Production example by emulsion polymerization ta+ Production of polyester resin having amphoteric groups 134 parts of bishydroxyethyl taurine and neopentyl were added to a 2β Kolbene equipped with a stirrer, a nitrogen inlet tube, a temperature control device, a condenser, and a decanter. 130 parts of glycol, 236 parts of azelaic acid, 186 parts of phthalic anhydride and 27 parts of xylene are charged and the temperature is raised. Water produced by the reaction is azeotroped with xylene and removed.

8. It takes about 2 hours from the start of reflux to raise the temperature to 190°C, continue stirring and dehydration until the acid value equivalent to carboxylic acid reaches 145, and then cool to 140°C.

The temperature was then maintained at 140°C, and 1-Kasula E1
314 parts of Perzatic acid glycidyl ester (manufactured by Shell) were added dropwise over 30 minutes, and stirring was continued for 2 hours to complete the reaction. The obtained polyester resin had an acid value of 59, a hydroxyl value of 90, and an M value of 1,054.

(bl N formation of microgels) In a 17! reaction vessel equipped with a stirrer, a cooler, and a temperature control device, 232 parts of deionized water, 10 parts of the polyester resin prepared in (a) above, and 0.0 parts of dimethylethanolamine.
75 parts were charged and dissolved while stirring while maintaining the temperature at 80°C, and a solution prepared by dissolving 4.5 parts of abviscyanovaleric acid in 45 parts of deionized water and 4.3 parts of dimethylethanolamine was added thereto. Then methyl methacrylate 70.7
parts, n-butyl acrylate 94.2 parts, styrene 70 parts
．． A mixed solution consisting of 7 parts of 2-hydroxyethyl acrylate, 30 parts of 2-hydroxyethyl acrylate, and 4.5 parts of ethyl alcohol dimethacrylate was added dropwise over a period of 60 minutes. After the dropwise addition, 1.5 parts of abbiscyanovaleric acid dissolved in 15 parts of deionized water and 1.4 parts of dimethylethanolamine was added.
When stirring was continued for 60 minutes at 0°C, the non-volatile content was 45%.
An emulsion having a pH of 7.2, a viscosity of 92 cps (at 25° C.) and a particle size of 0.156 μm was obtained. This emulsion was spray dried to obtain a microgel. Particle size is 0.8μ
Met.

rc Manufacture by solvent substitution from emulsion polymerization Microgel emulsion particles were obtained in the same manner as I-B, and substituted with Quijirole solution using azeotropy to obtain a microgel particle size of 0.2μ.
i'
;J.

(2) Production Example of Resin 11-1-1 Production of Acrylic Resin for Base Coat 80 parts of xylene and 10 parts of methyl isobutyl ketone were charged into a container equipped with a stirrer, a temperature control device, and a reflux condenser. Next, a solution of the following composition: Styrene 5.0 parts 0 Methacrylic acid 1.8 parts Methyl methacrylate 34.4 Ethyl acrylate 43.6 Isobutyl methacrylate 3.2 2-Hydroxyethyl acrylate 12.0 Azobisisobutylene 20 parts of 1.5 parts of ronitrile were added and heated while stirring to raise the temperature. While refluxing, the remaining 81.5 parts of the above mixed solution was added dropwise over a period of 3 hours, and then a solution consisting of 0.3 parts of azobisisobutyronitrile and 10 parts of quidylol was added dropwise over a period of 30 minutes. The reaction solution was further stirred and refluxed for 2 hours to increase the conversion rate to resin, and then the reaction was terminated to obtain an acrylic resin varnish with a nonvolatile content of 50% and a number average molecular weight of 18,000.

ll-1-2 Production of polyester for base coat The following raw materials were charged into a container equipped with a stirrer, a temperature control device, and a decanter, and heated while stirring.

Ethylene glycol 39 parts Neopentyl glycol 130 parts 1 Azelaic acid 236 parts Fucric anhydride 186 parts did. Thereafter, the temperature was cooled to 140° C., 314 parts of Cardura E-10 (epoxy resin, manufactured by Shell Co., Ltd.) was added, and stirring was continued for 2 hours to complete the reaction.

The obtained resin had an acid value of 9, a hydroxyl value of 9o, and a number average molecular weight of 1,050. This resin was diluted with xylene to a non-volatile content of 60% to obtain a polyester resin varnish having a Gardner viscosity of Y.

■-2 Production of film-forming resin for top clear coat -2-1 Using the same equipment as in Production Example n-1-1, 70 parts of xylene and 20 parts of n-butanol were charged, and then a solution of methacrylate with the following composition was added. Acid: 1.2 parts Styrene: 26.4 parts 2 Methyl methacrylate: 26.4 parts was added and heated while stirring to raise the temperature. While refluxing, the remaining 81.0 parts of the above mixed solution was added dropwise over 2 hours, and then 0.3 part of azobisisobutyroni-1-lyl and 10 parts of xylene were added.
of the solution was added dropwise over 30 minutes. The reaction solution was further stirred and refluxed for 2 hours to complete the reaction, and the nonvolatile content was reduced to 50%.
, an acrylic 1/1 fat varnish having a number average molecular weight of B000 was obtained.

l-2-2 Using the same equipment as Production Example Tl-1, -1, xylene 5
7 parts, n-butanol 6 parts, and then a solution of the following composition: styrene 30.0 parts ethylhexyl methacrylate 1-45, 2 parts ethylhexyl acrylate 1-5, 5 parts 2-hydroxyethyl methacrylate 16 .2 parts 3 methacrylic acid 3.1 parts Azobisisobutyronitrile 20 parts out of 4.0 parts were added and heated with stirring to raise the temperature. While refluxing, the remaining 84 parts of the above mixed solution were added dropwise over 2 hours, and then 0.5 part of abbisisobutyronitrile and 2 parts of xylene were added.
A solution consisting of 3 parts and 14 parts of n-butanol was added dropwise over 20 minutes.

The reaction solution was further stirred and refluxed for 2 hours to complete the reaction,
An acrylic resin varnish with a non-volatile content of 50% and a number average molecular weight of 1i 3400 was used.

n-2-3 (for clear) 12-hydroxystearic acid is self-condensed in a conventional manner to adjust the polyester so that the acid value becomes 15, and then glycidyl methacrylate is condensed with the remaining carboxyl groups of the polyether to stabilize it. A prepolymer was obtained. Subsequently, methyl methacrylate, glycidyl methacrylate and the stabilizer prepolymer were copolymerized in an ethyl acetate/butyl acetate-2/1 (weight ratio) solution in a weight ratio of 50:4:46, and then butyl acetate was copolymerized in a 2/1 (weight ratio) solution. A copolymer solution with a solids content of 33% was obtained. Next, the following mixture: above copolymer solution 08.982 parts methacrylic acid 0.440 dimethyl coconut amine 0.057 l/p-3rd
0.006 grade butylcatechol is heated at 111°C to reduce the acid value to 1 or less.

Furthermore, 0.683 parts of p-nitrobenzoic acid and 0.032 parts of dimethyl coconut amine were added, and the mixture was reacted at 111°C until the acid value of the mixture became 1 or less to obtain a stabilizer polymer solution. . This stabilizer polymer solution 4.8
parts, 1-16.7 parts of methyl methacrylate, 1.25 parts of azobisisobutyronitrile, and hexane/heptane = 1
/1 (weight ratio) 201, 6 parts of the mixed solution was quickly added to the solution heated to 80°C and maintained at that temperature for 25 to 30 minutes to form a seed particle dispersion of polymethyl methacrylate. The following mixture is then fed into this seed dispersion at reflux temperature over a period of 3 hours.

Styrene 114.9 parts 5 Methyl methacrylate 50.8 parts Hydroxyethyl acrylate 38.3 Butyl methacrylate 74.2 2-ethylhexyl acrylate 76.7 Methacrylic acid 10.0 The above stabilizer solution 110.8 Primary octyl mercapkun 1.2〃Azobisisobutyronitrile 2.6〃After the addition is completed, leave it for another 30 minutes or more, then divide 3.2 parts of azobisisobutyronitrile into 4 equal parts. at reflux temperature in 30 minute intervals. After the completion of the polymerization, the polymerization was maintained under reflux for 2 hours to complete the polymerization.

The solution containing the dispersed polymer and solution polymer thus obtained was cooled to 65°C, and
．． 0 parts, aromatic hydrocarbon (boiling point 190-210°C range)
A mixed solution consisting of 35.2 parts of isopropanol, 10.2 parts of isopropanol, and 43.8 parts of n-butanol is added. Finally 3
After cooling to 0°C, 28.8 parts of isopropanol, 46.3 parts of n-butanol, and aliphatic hydrocarbon (boiling point range 100~
120"C) 48.06 parts, aromatic hydrocarbon (boiling range 160-180°C) 43
．． Dilute with a mixed solution consisting of 9 parts. The resulting dispersion had a solid content of M42%.

■, Paint composition for base coat! lII! Construction l11-
1. Acrylic Silver Mekrysoku Paint Materials having the following composition were weighed into a stainless steel container and stirred with an experimental stirrer to prepare a paint composition.

Production Example IT-1-1 Varnish 100 parts 11F-2 Polyester white paint Resin Production Example Tl-1-2 Polyester FES 100 parts Titanium oxide R-5N (manufactured by Sakai Kagaku Co., Ltd.) 90 parts 7 nT-3 Acrylic silver metallic paint The following coating material 1 was obtained in the same manner as mi-i.

Production example n-Ll Acrylic Feswani 100 parts Aluminum paste 11.09 M8] 3 parts Desmodule N-7
Parts 5, 28, 8 IV I-Preparation of paint for Tsubu clear coat Weigh each of the following compositions in a stainless steel container, stir with a laboratory stirrer,
The paint for each production example was adjusted.

rv-t rV-1-11V-1-2 Production example Tl-2-1 Fes 100 parts 100 parts Knee pants 20SE-6036 parts 38 parts Microgel particles to I-8.1 parts rv-21V-2-I TV -2-2 Production example n-2-2 Varnish 100 parts 100 parts Knee pants 205E-6027, 8 parts 27.8 parts 8 TV-3TV-3-11V-3-2 Production example n-2-2 Fes 100 parts 100 Desmodur N-7516, 7 parts 16.7 parts rc microgel particle dispersion solution - 17, 5 parts IV-41V-/l-11V-4-2 Production Example 11-2-3 Dispersion 100 parts 100 parts Kneepan 205R - 6045 parts 46 parts I-B microgel particles - 6.2 parts The base paint of Paint Production Example 1-1 was mixed with the following mixed solvent (hereinafter referred to as base thinner) cellosolve acetate.
The mixture was diluted with 50 parts butyl acetate, 30 parts xylene and 20 parts at 20° C. in an M4 Ford cup for 15 seconds.

In addition, the top clear paints of paint production examples TV-1-1 and rV-1-2 were mixed with the following mixed solvent (hereinafter referred to as top clear thinner) 9 xylene 50 Swasol 1000 (Maruzen Sekiyu) 50 to 11k1
．． Dilution was adjusted to 25 seconds/20°C using 4 food cups.

Then, prepare two tin plates each that have been treated with solvent degreasing.
Place one sheet vertically and one horizontally, and apply 1 layer of base paint.
A dry film was applied in several coats to a thickness of 15 μm, and then left at room temperature for 3 minutes to form a base film. Then, the above-mentioned diluted top clear paint was applied in one coat on the base film in the following combination using Wesoton on Weso 1~. At this time, a dry clear film was applied at a gradient of 20 to 60 μm on the vertical tin plate, and a 35 μm thick dry film was applied on the horizontal tin plate. Then, after being left at room temperature for 5 minutes, it was baked in a dryer at 140° C. for 30 minutes. At this time, the vertical tin plate was baked vertically, and the horizontal tin plate was baked horizontally.

Comparative Example 1 Example 1 Base film m-i m-1 Top clear film TV-1-I IV-1-20 Regarding aluminum orientation, gloss, and texture, horizontal tin plate "2/2 coat/1. The sagging property of the clear was determined by the critical thickness at which the clear film would not sag using 2 coats/1 hake film on a vertical tin plate.

In a system in which no microgel was included in the clear, the orientation of aluminum was poor, and the gloss, sagging properties, and texture were poor.

(Under the same conditions as Example 1, dilute and adjust the base paint M-2 and top clear paints TV-2-1 and TV-2-2, and perform the painting baking process with the following combinations.) Removed 2 coats/1 bake solid film.

Comparative Example 2 Example 2 Base film T[l-21ff-2 Top clear film TV-2-I TV-2-2 As a result of the same determination as in Example 1, the molecular weight of the base and clear film-forming resins was lowered. However, all systems in which microgel was blended with clear were good. The results are shown in the table.

ηH skin ■ 1 Base grade 111-3 and clear paint TV-3-1
and TV-3-2 were diluted and painted in the same manner as in Example 1 using the following combinations, and then force-dried at 80° C. for 30 minutes to obtain a cured film.

Comparative Example 3 Example 3 Base film ITI-3l1l-3 1 to Tsubukuryar film TV-3- ] TV-3-2
By adding microgel to the clear, the aluminum alignment of the base coat and the gloss of the two-coat film were good, and the sagging properties of the clear film were significantly improved.

↓ Under the same conditions as Example 1, base coating m-1 and clear paints IV-4-1 and IV-4-2 were diluted and painted in the following combination, and then 140' C for 20 minutes to obtain a cured film.

Comparative Example 4 Example 4 Base film +11-I TIT-1 Top clear film IV-4-I TV-4-2 Even when the film-forming polymer for the top clear film was dispersed in two forms, it was deformed by the addition of microgel particles. Gives finished appearance and sagging performance.

(Left below) 3 Procedural Amendment November 3, 1980 Director General of the Patent Office 2. Title of the invention: "Wet-on-wet" two-coat clear paint composition 3.
Relationship with the case of the person making the amendment Name of the patent applicant: Nippon Paint Co., Ltd. 4, Spontaneity of the agent 6, Number of inventions increased by the amendment: None 7, Contents of the amendment to the specification subject to the amendment 1, Page 3, line 20 Correct "base coat" to "base coat".

2. Insert the following on page 8, line 11, after "reducing the viscosity by".

[Alternatively, when maintaining a high molecular weight, reduce the viscosity by dispersing the film-forming resin in a diluting solvent to form a non-aqueous dispersion.'' 3, page 8, lines 18 to 19 Delete "to".

4. On page 14, line 9, correct "silicone too" to "silicone ya."

5. Insert "(manufactured by Bayer)" after "Desmodule N-75J" on page 28, line 5.

6. Replace the table on page 34 with a separate sheet.

■

Claims (1)

[Scope of Claims] (]) A topcoat clear coating composition to be applied on a base coat by wet-on-wet, comprising a film-forming acrylic polymer having a functional group capable of reacting with a ta+ crosslinking agent; ) a volatile organic liquid diluent supporting the polymer; (C) a crosslinking agent dissolved in the organic liquid diluent;
+dl The above polymer (81 and diluent (bl and crosslinking agent (c)
crosslinked polymer fine particles having a particle size of 0.01 to 10μ, which are insoluble in the mixed system with 1 and stably dispersed in the acid system, and the crosslinked polymer fine particles (di is the polymer !a+, crosslinking agent (Cl and crosslinked polymer fine particles Td
0.2 to 20% by weight of the total solids weight of the composition. (2) The composition according to claim 1, wherein the film-forming acrylic polymer +al is an acrylic copolymer having hydroxyl groups and/or carboxyl groups. (3) The composition according to claim 1 or 2, wherein the film-forming acrylic polymer +8) is dissolved in a mixed system of a diluent (bl) and a crosslinking agent (Cl). The composition according to claim 1 or claim 2, wherein a film-forming acrylic polymer (al is insoluble in a mixed system of diluent (BL) and crosslinking agent (Cl)) is stably dispersed. (5) The film-forming acrylic polymer (Al is partially insoluble and stably dispersed in the mixed system of the diluent (BL) and the crosslinking agent (Cl), and the remainder is dissolved. The composition according to claim 1 or 2. (6) The composition according to any one of claims 1 to 5, wherein the crosslinking agent is an aminoplus 1 resin. A composition according to any one of claims 1 to 5, wherein the crosslinking agent is polyisocyanate-1.