JPS60250067A - Clear coating composition for top coat - Google Patents

Abstract

PURPOSE:To provide a microgel-contg. coating compsn. which can be used within a wide range of combination without loss of the transparency of coating film, prepd. by blending a film-forming polymer, an organic solvent, a crosslinking agent and a crosslinking polymer in fine particles having a specified refractive index. CONSTITUTION:The coating compsn. contains (A) a film-forming polymer with a functional group capable of reacting with a crosslinking agent, (B) a volatile organic solvent as diluent for (A), (C) a crosslinking agent dissolved in (B) and (D) a crosslinked polymer in fine particles which are insoluble in a mixt. of (A), (B) and (C) but are dispersible in the system under a stabilized condition. (D) accounts for 0.2-20% of the total solid weight of (A), (C) and (D). The compsn. is obtained by emulsion polymerization of an ethylenically unsatd. monomer and a crosslinking comonomer in such amts. that the relation between the refractive index of (D) [nDd] and that of (A) [nDa] may satisfy the equation.

Description

DETAILED DESCRIPTION OF THE INVENTION Limb Blood Field The present invention relates to a top coat clear paint composition used as a top coat for painting automobile bodies, for example.

'and. For example, as a painting method for automobile bodies, a clear coat is applied by a wet-on-wet method on a base coat containing colored pigments and/or metallic pigments, and the entire coating film is simultaneously baked or cured at room temperature, so-called two-coat one-bake painting. is being widely implemented. Furthermore, it is widely practiced to apply a clear topcoat to form a transparent coating film on aluminum or stainless steel materials for the purpose of retaining the color tone of the material itself and imparting corrosion resistance and aesthetics.

In order to obtain a high finished appearance in these methods, especially in two-coat systems, one method is to apply a thick clear coating. However, ordinary clear paint compositions have poor sagging properties and cannot be applied thickly in one coat. That is, in one stage painting, the coating thickness is at most 20 to 30 microns. 1 stage 2
Thick coating is possible if the thickness is more than one stage, but this is difficult to implement because it not only increases the number of steps and lowers productivity, but also requires modification of the existing line.

Therefore, in recent years, crosslinked polymer fine particles (hereinafter referred to as "microgel"), which are insoluble in these systems and which impart structural viscosity to paints, have been added to the usual system consisting of a film-forming polymer, a crosslinking agent, and a diluent. Paints with added additives have attracted attention as paints that have improved sagging performance and can be coated thickly with fewer coats. For example, JP-A-41-9
See No. 7026, etc.

In the paint containing microgel, it is essential for the microgel to be insoluble in its dispersion medium (generally consisting of a film-forming polymer, a crosslinking agent, and their solvent) in order to exhibit its characteristics. Naturally, the particles are dispersed in a non-uniformly dispersed state within the coating film formed from the coating material. At this time, if the optical refractive index of the microgel is different from that of the surrounding film-forming polymer, diffuse reflection of light will occur at the interface, and the entire coating will appear white and opaque. The purpose of the clear top coat is to improve the appearance quality by being transparent, so if it becomes opaque it will actually deteriorate the appearance.

This is why JP-A-49-97026 cited above requires that the refractive index of the microgel be substantially the same as that of the main film-forming polymer. However, the microgel used there is N
It is manufactured using a method called the AD method. In other words, the NAD method involves combining an ethylenically unsaturated monomer and a crosslinkable copolymer in the presence of a stabilizer in a non-aqueous organic solvent that dissolves the aliphatic hydrocarbon ring but does not dissolve the polymer. However, in order to prevent the polymer from dissolving, the monomers constituting the microgel are limited to those having a solubility parameter comparable to that of the non-aqueous organic solvent used. Therefore, the fluctuation width of the refractive index is also within a relatively narrow range, and the type of film-forming polymer that can be used in combination with this is also limited.

The object of the present invention is to overcome these drawbacks of the prior art and
An object of the present invention is to provide a clear paint composition for top coating containing microgels that can be combined in a wide variety of ways without impairing the transparency of the formed coating film.

Solution: The clear top coating composition of the present invention comprises (a) a film-forming polymer having a functional group capable of reacting with a crosslinking agent, and (b) a volatile organic liquid diluent supporting the polymer. and (C1 a crosslinking agent dissolved in the organic liquid diluent, +
d) The polymer + al and diluent (bl and crosslinking agent (C1)
and crosslinked polymer fine particles that are insoluble in the mixed system with the acid system and stably dispersed in the acid system.

The crosslinked polymer fine particles (dl, or microgel) are composed of the polymer (al), the crosslinking agent (C1), and the microgel fd.
+ accounts for 0.2 to 20% by weight of the total solids weight.

The present invention provides the microgel (dl is its refractive index nDd
is in relation to the refractive index nDa of the polymer (al),
It is a microgel obtained by emulsion polymerization of an ethylenically unsaturated monomer and a crosslinkable comonomer, the type and amount of which are selected in advance so as to satisfy the relationship 1nDd-nDal≦0.05. It is characterized by

The microgel contained in the composition of the present invention is produced by emulsion polymerizing an ethylenically unsaturated monomer with a crosslinkable comonomer in an aqueous medium to create a fine particle copolymer, and then removing water. Ru. Unlike the aliphatic hydrocarbons used in the NAD method, water has a high solubility parameter of about 23, which is significantly different from the solubility parameter of ordinary organic polymers, so it does not dissolve most organic polymers. Therefore, microgels that cannot be produced by the NAD method because they dissolve or swell in non-aqueous organic solvents can be produced by emulsion polymerization, and microgels with different refractive indexes over a relatively wide range can be obtained. Therefore, according to the present invention, it is possible to combine a wide range of film-forming polymers and microgels without impairing transparency, and it is possible to provide compositions that satisfy various required performances.

Furthermore, in recent years, attention has been focused on reducing the amount of solvent in paints to reduce the amount of solvent used to make them high solids due to requests for resource conservation and anti-pollution measures.The clear paint composition of the present invention makes it possible to achieve high solids paints without adversely affecting the performance of the finished coating. do.

Film-forming polymer (81) having a functional group capable of reacting with a crosslinking agent used in the present invention is generally known. These include acrylic copolymers, polyesters, alkyds, etc. has a functional group such as a hydroxyl group or a carboxyl group that can react with a crosslinking agent, and has the protective properties necessary as a clear top coat, such as cracking, whitening, etc.
It must exhibit weather resistance, solvent resistance, chemical resistance, impact resistance, etc. against peeling and gloss reduction, and it must also have a decorative function. Therefore, the acid value is usually between 0.5 and 40.
, preferably 2 to 30, and a hydroxyl number of 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.

Acrylic copolymers are composed of an alkyl ester of allylic acid or methacrylic acid, optionally other ethylenically unsaturated monomers that can be copolymerized therewith, and a monomer having 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-hydroxypropyl (meth)acrylic acid, N-(butoxymethyl)-
(meth)acrylamide, glycidyl (meth)acrylate, etc.

Additionally, a monomer that can act as a catalyst for the crosslinking reaction between the polymer 81 and the crosslinking agent can be incorporated into the acrylic polymer; for example, acrylic acid and methacrylic acid are commonly used, but sulfonate Acid groups can be introduced into the polymer using group-containing monomers such as 2-sulfoethyl methacrylate and acidic butyl maleate.

Even if the film-forming polymer used in the present invention (al is an organic liquid diluent) and the crosslinking agent (C1) are dissolved in the mixed system, or even if they are stably dispersed without being melted, some may be melted and the remainder may be dispersed.

As the polymerization method, known solution 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, formaldehyde condensates of aminoplast resins, that is, nitrogen-containing compounds such as urea, thiourea, melamine, and benzoguanamine, and lower alkyl ethers (alkyl The number of carbon atoms in the group is 1 to 4).

The blending amount of the crosslinking agent is based on the film-forming polymer (al
and crosslinking agent (5 to 50% by weight, preferably 10 to 40% by weight of the total solid content of BL).

The microgel (d) used in the present invention is obtained by emulsion polymerizing an ethylenically unsaturated monomer and a crosslinkable comonomer in an aqueous medium by a known method to create an elmudgeon containing crosslinked polymer fine particles. It is obtained by removing water by solvent substitution, azeotropy, centrifugation, filtration, drying, etc. Emulsion polymerization may be carried out using known emulsifiers and/or dispersants, but it is preferable to use emulsifiers having amphoteric ionic groups. When a microgel is added to a coating composition, its structural viscosity varies depending on the particle size, so it is important to obtain a uniform particle size. However, by using an emulsifier with a zwitterionic group, a microgel with a uniform particle size can be obtained. This is because it is easy to obtain.

Examples of ethylenically unsaturated monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Alkyl esters of acrylic acid or methacrylic acid and other monomers having ethylenically unsaturated bonds that can be copolymerized with them, such as styrene, α-methylstyrene, vinyltoluene, t-butylstyrene, ethylene, propylene, acetic acid Vinyl, vinyl propionate, acrylonitrile, methacrylate trile, dimethylaminoethyl (meth)acrylate, etc. Two or more types of these monomers may be used.

Crosslinkable comonomers are monomers and/or monomers having two or more radically polymerizable ethylenically unsaturated bonds in the molecule.
Alternatively, it contains two types of ethylenically unsaturated group-containing monomers each carrying groups that can react with each other.

Monomers having two or more radically polymerizable ethylenically unsaturated groups in the molecule include polymerizable unsaturated monocarboxylic acid esters of polyhydric alcohols, polymerizable unsaturated alcohol esters of polybasic acids, and There are aromatic compounds substituted with one or more vinyl groups, examples of which include the following compounds.

Ethylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, L3-butylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, 1,4-butanediol diacrylate, Neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, pen erythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, glycerol dimethacrylate, glycerol Diacrylate, glycerol allyloxy dimethacrylate, LL, 1-1-lishydroxymethylethane diacrylate, 1. LL-trishydroxymethylethane triacrylate, LLI-trishydroxymethylethane dimethacrylate, 1.1
．． 1-trishydroxymethylethane trimethacrylate, I, Ll-1-lishydroxymethylpropane diacrylate, Ll, 1-trishydroxymethylpropane triacrylate, 1.1.1-trishy[roxymethylpropane dimethacrylate, 1.1 .1-) Lishydroxymethylpropane trimethacrylate, triallyl cyanurate, trially, lysocyanurate, triallyl trimellitate, diallyl terephthalate, diallyl phthalate and divinylbenzene.

Furthermore, in place of the monomer having two or more radically polymerizable ethylenically unsaturated groups in the molecule as a monomer for crosslinking purposes, or optionally together with them, each carries a group capable of reacting with each other. It is also possible to use monomers with some ethylenically unsaturated groups. For example, glycidyl group-containing ethylenically unsaturated monomers such as glycidyl methacrylate and glycidyl acrylate, acrylic acid,
Carboxyl group-containing ethylenically unsaturated monomers such as methacrylic acid and crotonic acid; 2-hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxytyl acrylate, hydroxybutyl methacrylate, allyl alcohol, meth Examples include hydroxyl group-containing ethylenically unsaturated monomers such as allyl alcohol, and isocyanate group-containing ethylenically unsaturated monomers such as vinylnesocyanate and isopropenyl isocyanate. However, in addition to these, any combination of two ethylenically unsaturated monomers each carrying a group capable of reacting with each other can be used.

The monomer constituting the microgel may include a monomer having a functional group that can react with a crosslinking agent, such as a carboxyl group-containing monomer such as acrylic acid,
Methacrylic acid, crotonic acid, itaconic acid, maleic acid,
fumaric acid, hydroxyl group-containing monomers such as 2-hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate,
Allyl alcohol, methacrylic alcohol, and nitrogen-containing alcohols include acrylic acid amide and methacrylic acid amide.

The refractive index (nDd) of the crosslinked polymer fine particles is 1nDd - nDa with respect to the refractive index (nDa) of the film-forming resin.
It should be in the range 1=0.05, preferably in the range 0.03. If it exceeds this range, the clear coating will become cloudy and the finished appearance will be poor. The refractive index of the film-forming resin is determined by AbbeRefractome after forming the film-forming resin into a film with a thickness of 30 to 50 μm.
er (manufactured by TAGO Co., Ltd.) at 20° C. using α-bromonaphthalene as a medium.

The refractive index nDd of crosslinked polymer fine particles (microgel) is determined by the following formula.

nDd = ΣC1n], Cznz −・φ−Cmnm
However, the CIl C2... button indicates the weight fraction of each monomer constituting the microgel (C1+Cz+...Cn=1
), and ns, nz...nm are the refractive indexes at 20° C. of a single polymer of each monomer.

The microgel used in the present invention may have a uniform structure or
Alternatively, the particle may have a multilayer structure with a layer structure within the particle.

In the case of a multilayer structure, the final surface layer is prepared so that the difference in refractive index of the entire microgel with the surrounding film-forming polymer in the coating is in the range of 1 nDd - nDa l ≦ 0, 0'5, The inner layer can be a so-called functionally divided microgel, such as a layer for providing other functions, for example, structural viscosity.

The blending amount of this microgel is determined by the amount of film-forming polymer (a
), the crosslinking agent (C), and the microgel (d) in a total solid content of 0.2 to 20% by weight, preferably 1 to 15% by weight. If the amount of microgel is too small, the clear composition tends to sag, and in the case of sea urchin/notonwesoto coating, it penetrates into the hair coat composition too much, 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 and a high finished appearance will not be obtained.

The organic liquid diluent 1b) used in the present invention can be any organic liquid or liquid mixture commonly used as a solvent for polymers in conventional coating compositions, such as hexane,
aliphatic hydrocarbons such as heptane, aromatic hydrocarbons such as toluene or xylene, petroleum fractions of various boiling point ranges consisting primarily of aliphatic hydrocarbons but containing some aromatic hydrocarbons, butyl acetate, ethylene glycol dicarbonate, esters such as acetate, 2-ethoxyethyl acetate,
Ketones such as acetone and methyl isobutyl ketone, and alcohols such as butyl alcohol. It goes without saying that these should be selected appropriately depending on the type of film-forming polymer (al) or the supporting form of the polymer (al) in the diluent (b), that is, whether it is in the form of a solution or a dispersion. Furthermore, when a polyisocyanate compound is used as the crosslinking agent (C), it is a matter of course that it must not have an active hydrogen group that reacts with it.

In addition to the above-mentioned +a+ or dl components, the composition of the present invention includes other commonly used components, such as viscosity modifiers such as organic montmorillonite, polyamide, and polyethylene wax,
Surface conditioning agents for silicone and organic polymers, ultraviolet viewing agents,
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 a resin (al and a diluent (bl) is mixed and prepared, and a crosslinking agent (C) and a microgel (dl) are added thereto. It can be prepared by mixing (mixing) and adjusting the viscosity to an appropriate level with a diluent, if necessary.

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 onto an object to be coated by a conventional method, or applied wet-on-wet onto a formed hair coat film, and cured at room temperature or by heating to achieve a transparent, high-quality appearance. A clear coating or a two-coat coating can be formed.

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

Example 134 parts of bishydroxyethyl taurine, 130 parts of neopentyl glycol, 236 parts of azelaic acid, 186 parts of phthalic anhydride and 27 parts of xylene were added to a 21 Colchen equipped with a stirrer, a nitrogen inlet tube, a temperature control device, a condenser, and a decanter. Prepare and raise the temperature. Water produced by the reaction is azeotroped with xylene and removed.

The temperature was raised to 190'C over about 2 hours from the start of reflux, stirring and dehydration were continued until the acid value equivalent to carboxylic acid reached 145, and then the mixture was cooled to 140C.

The temperature was then maintained at 140°C and the "Cardura E10"
314 parts of persatic acid glycidyl ester (manufactured by Shell) were added dropwise over 30 minutes, and stirring was continued for 2 hours to complete the reaction. The resulting polyester resin has an acid value of 59. The hydroxyl value was 90 and MH1054.

1-1 Preparation of microgel Example 2 (1-layer powder) Into 11 reaction vessels equipped with a stirrer, a cooler, and a temperature control device, 232 parts of deionized water, 10 parts of the polynystyl resin obtained from the above (Al) and 0.75 parts of dimethylethanolamine was charged and dissolved while stirring while maintaining the temperature at 80°C, and a solution in which 4.5 parts of azobiscyanovaleric acid was dissolved in 45 parts of deionized water and 4.3 parts of dimethylethanolamine was prepared. Then 70.7 parts of methyl methacrylate, n-
Butyl acrylate 94.2 parts, methylene 70.7 parts,
A mixed solution consisting of 30 parts of 2-hydroxyl 7-acrylate and 4.5 parts of ethylene glycol dimethacrylate was added dropwise over 60 minutes. After the dropwise addition, 1.5 parts of asohiscyanovaleric 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 with a pH of 7.2 and a viscosity of 92 cps (25° C.) is obtained. This emulsion was spray dried to obtain a microgel. The particle size was 0.8μ.

The refractive index of the microgel was calculated using the above formula, and was found to be 1.
It was 510. However, the following values were used for the refractive index of a single polymer of each monomer.

Polymethyl methacrylate = 1.489 polystyrene
-1.591 Ethylene glycol dimethacrylate = 1.506 Poly n-butyl acrylate-1- = 1.4662-Hydroxyethyl methacrylate-) = 1.5121-2 Micronor゛[2<1 layer powder)! A microgel was produced in the same manner as in Example 1-1 using the same formulation and conditions except for the polymerized monomer. Monomer composition: 189 parts of methyl methacrylate, n-
The contents were 54 parts of butyl acrylate and 2 parts of ethylene glycol dimethafrylate.

The refractive index of the microgel was determined in the same manner as I-1.
．． It was 486. The powder particle size was 1.2μ.

1-3 Microgel 3 (1-layer powder) A microgel was produced in the same manner as in 1-1 using the same formulation and conditions except for the polymerized monomer. Monomer composition: 243 parts of n-butyl acrylate, 2 parts of ethylene glycol dimethacrylate
There were 7 parts.

The refractive index was 1.470. The powder particle size was 1.0μ.

1-4 Microl 4 (Single-layer solvent substitution) The same procedure as in rt was carried out, except for the polymerizable monomer, using the same formulation and the same conditions until the emulsion polymerization was completed. However, after that, the dispersion was replaced with a quijirole solution using azeotropy to obtain a quijirole dispersion with a microgel particle size of 0.2 μm and a microgel content of 40% by weight in the solution. The polymerizable monomer composition at this time was 216 parts of styrene, 27 parts of n-butyl acrylate, and 27 parts of ethylene glycol dimethacrylate, and the refractive index was 1.571.

1-5 Microgel ゛ 5 (Two-layer solvent replacement) I-1
Using the same apparatus as above, 232 parts of deionized water, 10 parts of the polyester resin obtained from (al) and 0.75 parts of dimethylethanolamine were placed in a reaction vessel, and dissolved while stirring while maintaining the temperature at 80°C. Then, a solution prepared by dissolving 1.0 part of azobiscyanovaleric acid in 20 parts of deionized water and 0.260 parts of dimethylethanolamine is added.Next, a mixed solution consisting of 108 parts of methyl methacrylate and 27 parts of ethylene glycol dimethacrylate is added. was added dropwise over a period of 60 minutes.Then, the first stage reaction was completed by keeping the temperature at BO℃ for 60 minutes, and 0.5 part of azobis(Schiff)valeric acid, 25 parts of deionized water, and 0.3 parts of dimethylethanolamine were added thereto. Add the solution dissolved in one part. Subsequently, 9.5 parts of styrene, 20 parts of methyl methacrylate, 1 part of n-butyl acrylate
4 parts of ethylene glycol dimethacrylate and 6 parts of ethylene glycol dimethacrylate were added dropwise over a period of 60 minutes. After dropping, add 1.5 parts of azobiscyanovaleric acid to 1 part of deionized water.
5 parts of dimethylethanolamine and 1.4 parts of dimethylethanolamine were added and stirred for 60 minutes at 80°C to complete the two-step reaction. As a result, the non-volatile content was 45%, the pH was 7.2, and the viscosity was 1.
An emulsion with a particle diameter of 0.2 p is obtained at 0.05 cps (25° C.).

This emulsion was subjected to solvent substitution for Qysilol in the same manner as in Production Example 1-4 to obtain a Qysilol dispersion with a microgel content of 40% by weight. The microgel particle size in this solution is 0.
It was 25μ. The refractive index of the microgel as a whole is 1
．． 527, the refractive index of the interior (core) produced in the first stage reaction was 1.492, and the refractive index of the exterior (shell) produced in the second stage was 1.559.

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: methacrylic acid 1.8 parts methyl methacrylate 39.4 parts ethyl acrylate 43.6 parts isobutyl methacrylate 3.2 parts 2-hydroxyethyl acrylate-z2. om azobisisobutyronitrile 20 parts out of 1.5 parts were added and heated while stirring to raise the temperature. While refluxing, the remaining 81.5 parts of the mixed solution was added dropwise over 3 hours, and then a solution consisting of 0.3 parts of azobisisobutyronitrile and 10 parts of quidylol was added dropwise over 30 minutes. After stirring and refluxing the reaction solution for another 2 hours to increase the conversion rate to resin,
After the reaction was completed, the non-volatile content was 50% and the number average molecular weight was 180.
00 acrylic resin varnish was obtained.

A 35μ thick acrylic resin film was made from this varnish, and the refractive index was 1.4 using the Abbe refractive index meter.
It was 79.

Using the same equipment as in Production Example 11-1, 57 parts of xylene,
Charge 6 parts of n-butanol, then make a solution of the following composition: 30.0 parts of styrene, 45.2 parts of ethylhexyl methacrylate, 5.5 parts of ethylhexyl acrylate, 16.2 parts of 2-hydroxyethyl methacrylate, 3.1 parts of methacrylic acid. 20 parts out of 4.0 parts of azobisisobutyronitrile were added and heated while 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 azobisisobutyronitrile 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 nonvolatile content of 50% and a number average molecular weight of 3,400 was obtained.

When the refractive index was measured, it was 1.521.

IF-3 Polyester 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 Azelaic acid 236 parts Phthalic anhydride 186 parts . The temperature was then cooled to 140'c and Cardura E-10
314 parts of epoxy resin (manufactured by Shell) were added and stirring was continued for 2 hours to complete the reaction.

The resulting resin had an acid value of 9. Hydroxyl value 90. The number average molecular weight was 1050. 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.

The refractive index of the dried film of this product was measured with an Abbe refraction needle and found to be 1.532.

■ Rikan Group 11 The following compositions were weighed into a stainless steel container and stirred using an experimental stirrer to prepare paints for each production example.

Production Example If-1 Varnish 100 parts 100 parts Microgel particle powder of 1-3 -3.6 parts Modaflow (manufactured by Monsanto) 0.2 parts 0.2 parts Microgel content 4.8% m-222? IJ2A-de knee 1-2i [1-25th production example n-2 worth 100 parts 100 parts knee huff
2O-5E-6055 parts 55 parts Microgel particles of 1-3 9.2 parts - Microgel particles of T-2 --9,2
Part Production Example n-3 Varnish 100 parts ioo Part 1-3 Microgel particles 2.5 parts -r-i Microgel particles
-2.5 parts Azitol YL-480 (manufactured by Hoechst) 0.2 parts 0.
2 parts Production example 11-2 Varnish 100 parts 100 parts 1-3
Microkel particles 7 parts = Dispersion of 1-5 - 17.5 parts Para-toluenesulfonic acid 161913m-5 Chestnut 1 [1-5 Production example n-2 Varnish 100 parts Dispersion of 1-5 10 parts Modaflow 0. 1 part I-6 - 21L material - Futjishio Y-Otori, ±4 and I Yuhan 205E-60 15 parts Modaflow 0.3 parts Titanium oxide R-5N (manufactured by Sakai Chemical Co., Ltd.) 90 parts in a dispersion container The mixture was weighed, mixed and dispersed using a paint conditioner, and 1 part of Super Hesocamine G-821-603 and 1 part of Toray Silicone Sl+-290 were added to prepare a paint.

On the fruiting tray ↓ Paint production example 111-1-1 (Example I) and l1l
-1-2 (Comparative Example 1) clear paint was mixed with the following mixed solvent (hereinafter referred to as clear thinner) xylene 50 Swasol 1000 (Maruzen Sekiyu) 50 No. 4
Dilution was adjusted to 25 seconds/20°C using a food cup. Then, on the solvent-degreased aluminum plate material, use Air Spray Gun Wider #71 (manufactured by Iwata Toki Co., Ltd.) to paint a dry film of 35μ in one coat, leave it at room temperature for about 10 minutes, and then dry it at 140℃. Bake in a pot for 30 minutes.

In Comparative Example 1, in which a microgel having a refractive index significantly different from that of the film-forming resin was used, the clear coating film became cloudy and rough, and there was no impression of an aluminum base. In comparison, in Example 1, a transparent coating film with good skin appearance was obtained.

Actual No. 12 and Ratio 412 The base paint of Production Example 111-6 was diluted with the following mixed solvent (hereinafter referred to as base thinner) Cellosolve Acetate 50 Butyl acetate 30 Xylene 20 No., 4 food cups for 15 seconds at 20°C. It was adjusted. Also, paint production example 111-2-L I[l-2
-2 clear paint was diluted to 720°C for 25 seconds with clear thinner using an M4 Ford cup. Therefore, the diluted base paint was applied in two coats to a dry film thickness of 20 μm on two solvent-degreased tin plates, and then left at room temperature for 3 minutes. Next, Ill-2-1 (Comparative Example 2) was applied wet-on-wet onto the base film.

The clear diluted paint of l1l-2-2 (Example 2) was applied in the same manner as in Example 1 to form a dry film of 35 μm on each base film.
I set it to Then, after leaving it at room temperature for 5 minutes,
It was baked for 30 minutes in a dryer at 0°C.

A clear film using microgel with a refractive index difference of 0.05 or less was transparent even in a two-coat, one-bake film, and the metallic feel of the base was still visible, giving a good finish. On the other hand, in Comparative Example 2, the coating appeared cloudy and yellowed.
I couldn't change the metallic feel.

-3 and External l Production Example 111-3-1 (Comparative Example 3) and lT[-3
-2 (Example 3) with clear thinner, IIIo, 4
Diluted in a food cup for 25 seconds/20°C, Example 1
A film was obtained on an aluminum plate in the same manner as above and evaluated. The film using microgels with similar refractive index was transparent and good.

-' 4 and 4 Manufacturing Example ■-7 Base solid color paint was treated with base thinner in an N1114 food cup for 18 seconds at 20°C.
A base film was prepared in the same manner as in Example 2. Next, Production Example 111-4-1 (Comparative Example 4) and l
-4-2 (Example 4) Paint? Positive 4 with clear thinner
Diluted in a Ford cup for 25 seconds/20°C, Example 2
In the same manner as above, wet-on-wet (interval 3 minutes) was applied to the solid color base film, and 45% was applied to the dry film.
μ was set, coated, exposed at room temperature for 5 minutes, and then baked at 140° C. for 30 minutes to obtain a 2-coat, 1-hex solid coating.

Example 4 had a transparent and good coating film appearance, but Comparative Example 4 was opaque and had a rough texture, and the appearance was more like a 1-coat solid than a 2-coat coat. 2 with paint thinner
5 seconds/20°C/N [1,4 diluted in a food cup, applied on an aluminum plate in the same manner as in Example 1, left at room temperature for 10 minutes, and then force-dried at 100°C for 30 minutes to obtain a clear film. . A transparent coating film with a textured feel was obtained.

The results of Examples and Comparative Examples are shown in the table below.

Procedural amendment 1, Indication of the case 1982 Patent Application No. to7zt'i' 2, Name of the invention Clear paint composition for top coating 3, Person making the amendment Relationship to the case Patent applicant name Title Nippon Paint Co., Ltd. 4, Agent Address: Koei Building, 2-40-4 Awajicho, Higashi-ku, Osaka Name (6036) Patent Attorney Takuo Akaoka... 5 Date of amendment order 6 Number of inventions increased by amendment None Contents of amendment 1 , page 16, line 17 of the specification, r=0.05. J is corrected as [≦0.05J, and rO,03J is corrected as [≦0.03J.

2. On page 34, line 13, the phrase "5 minutes after the sensing device" is corrected to "after being left for 5 minutes."

3. Replace page 30 with the attached sheet.

1-3 Microgel particles 2.5 parts - 1-1 Microgel particles 2.5 parts Aditol XL-480 (manufactured by Hoechst) 0.2 parts 0.
2 parts Production example n-2 Fes 120 parts 120 parts Microgel particles of 1-3 7 parts - Dispersion of 1-5 -17.5 parts Para-toluenesulfonic acid 1 part IB Production Example n-2 Varnish 100 parts Dispersion of 1-5 10 parts Modaflow 0.1 part

Claims (1)

[Scope of Claims] (11(al) a film-forming polymer having a functional group capable of reacting with a crosslinking agent, (b) a volatile organic liquid diluent supporting the polymer, (C1 the organic liquid A crosslinking agent dissolved in a diluent and (
dl The above polymer (al, diluent (b) and crosslinking agent (C1)
and crosslinked polymer fine particles that are insoluble in the mixed system and stably dispersed in the system, and the crosslinked polymer fine particles +dl include the polymer (a), the crosslinking agent (C), and the crosslinked polymer fine particles. The crosslinked polymer fine particles +dl account for 0.2 to 20% by weight of the total solid weight of the polymer fine particles Td), and the crosslinked polymer fine particles +dl have a refractive index nDd of 1n in relation to the refractive index nDa of the polymer +a).
It is obtained by emulsion polymerization of an ethylenically unsaturated monomer and a crosslinkable comonomer, the type and amount of which are selected in advance so as to satisfy the relationship Dd-nDal≦0.05. Clear paint composition for top coat with characteristics. (2) The composition according to claim 1, wherein the film-forming polymer (al is an acrylic copolymer having a hypoxyl group and/or a carboxyl group). (3) The film-forming polymer (al is a diluent (b
(4) The film-forming polymer fat is dissolved in a mixed system of a diluent fb and a crosslinking agent (C).
3. The composition according to claim 1 or 2, which is insoluble and stably dispersed in a mixed system of (C) and crosslinking agent (C). (5) A patent claim in which the film-forming polymer (al) is partially insoluble and stably dispersed in the mixed system of the diluent (bl) and the crosslinking agent (C), 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 aminoplast resin. (7) The crosslinking agent is an aminoplast resin. The composition according to any one of claims 1 to 5, which is a polyisocyanate.