JPH0423593B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application and Problems to be Solved by the Invention] The present invention relates to a novel and useful metallic finishing method, and more particularly, the present invention relates to a novel and useful metallic finishing method. A metallic coating that is particularly applicable to elastic materials (elastoplastics), which consists of using a paint containing the curing agent as an essential base resin component (film-forming component) for both the base coat and the clear coat. Concerning finishing methods. [Prior Art] In recent years, various plastics have been adopted in the automobile industry for the purpose of improving safety and reducing weight. However, when plastics are generally used as exterior panels of automobiles, they are often coated to improve weather resistance or give them an aesthetic appearance. The coating film used in this case not only needs to have excellent durability, appearance, and chemical resistance, especially as a top coat for automobiles, but also needs to have mechanical properties such as flexibility and impact resistance at low temperatures. They are also required to be of excellent quality. Furthermore, when using thermosetting resin paint,
The coating must be capable of being thermally cured at a temperature below the temperature limit of the plastic to which it is applied. By the way, at present, a method of using isocyanate-modified polyester resin as a thermosetting resin paint for elastic plastics has been proposed, but since the main component of such paint is polyester, it is difficult to create a metallic finish. In particular, it has insufficient durability and chemical resistance to be used as a clear coat finishing method in a two-coat one-bake system, and is therefore considered difficult to put into practical use. On the other hand, when thermosetting acrylic resins, which are currently used to paint automobile steel plates, are applied to this type of elastic plastic coating, although they have good durability and chemical resistance, they have poor flexibility at low temperatures. In order to improve these mechanical properties, the glass transition point (Tg) of acrylic resin is lowered, or plasticizers are added to improve the durability. This results in a significant decrease in chemical resistance and makes it unsuitable for practical use. In the end, conventional paints generally have difficulty in balancing durability and chemical resistance with flexibility and impact resistance, and the emergence of resins with a good balance of these properties. is awaited. [Means for Solving the Problems] However, as a result of intensive research in view of the above-mentioned circumstances, the present inventors have found that, in particular, in the metallic finishing of elastic plastic substrates using the two-coat, one-bake method, the base coat and clear coat Appearance, durability, and chemical resistance are improved by applying a specific thermosetting resin paint containing an ε-caprolactone-modified hydroxyl group-containing copolymer and its curing agent as essential components to each coat. They discovered that a coating film with excellent flexibility and impact resistance at low temperatures can be obtained, and completed the present invention. That is, in the present invention, a paint (base coat) containing a thermosetting resin as a base resin component (film-forming component) is applied, which is a mixture of metallic powder and, if necessary, a coloring pigment. In the metallic finishing method, which consists of applying a paint (clear coat) containing the same type of thermosetting resin as the base resin (film-forming component), and then curing it by heating, the essential resins of these base coats and clear coats are Each component has a structural formula in the molecule. [However, n in the formula shall be an integer of 1 or 2 or more. ] Contains a side chain represented by 5 to 60% by weight,
Furthermore, the hydroxyl group-containing copolymer (A) has a number average molecular weight of 7,000 to 20,000 and a Tg of -40°C to 0°C.
[ε-caprolactone modified hydroxyl group-containing copolymer (A)]
and the curing agent (B) for the ε-caprolactone-modified hydroxyl group-containing copolymer (A) in an amount of 10 to 80 parts by weight of the curing agent (B) per 100 parts by weight of the copolymer (A). The object of the present invention is to provide a metallic finishing method which is particularly applicable to elastic plastics, and which consists of using a mixture in proportions of 1. Here, the above-described ε-caprolactone-modified hydroxyl group-containing copolymer (A) is, for example,
The method using polycaprolactone-modified hydroxyalkyl acrylic acid ester disclosed in Japanese Patent Publication No. 182536, or the method disclosed in JP-A-18254-
It is disclosed in Publication No. 13359. It can be prepared by a known method such as adding ε-caprolactone to a previously obtained hydroxyl group-containing copolymer. At that time, it is used to prepare the hydroxyl group-containing copolymer (A). Typical examples of copolymerizable unsaturated monomers include styrene, α-methylstyrene, p
- Aromatic vinyl monomers such as tert-butylstyrene or vinyltoluene; methyl (meth)acrylate, ethyl (meth)acrylate, n-
Propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate,
tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, dibromopropyl (meth)acrylate, tribromophenyl (meth)acrylate or alkoxylalkyl (meth)acrylate various (meth)acrylates such as; diesters of unsaturated dicarboxylic acids such as maleic acid, fumaric acid or itaconic acid with monohydric alcohols; vinyl ester)
Various vinyl esters such as “viscoat”
8F, 8FM, 3F or 3FM” [Osaka Organic Chemical Co., Ltd.]
fluorine-containing acrylic monomer], perfluorocyclohexyl (meth)acrylate, Jeeperfluorocyclohexyl fumarate or N-
Fluorine-containing compounds such as (per)fluoroalkyl group-containing vinyl esters, vinyl ethers, (meth)acrylates, or unsaturated polycarboxylic acid esters such as i-propyl perfluorooctane sulfonamide ethyl (meth)acrylate; Or vinyl monomers without so-called functional groups (polar groups) such as (meth)acrylonitrile, vinyl chloride, vinylidene chloride, vinyl fluoride, or olefins such as vinylidene fluoride; 2-hydroxyethyl (meth)acrylate , 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 3-chloro- 2-hydroxyethyl (meth)
hydroxyalkyl esters of α,β-ethylenically unsaturated carboxylic acids such as acrylate, di-2-hydroxyethyl fumarate, mono-2-hydroxyethyl-monobutyl fumarate or polyethylene glycol mono(meth)acrylate; ) α,β-ethylene, such as unsaturated mono- or dicarboxylic acids such as acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid or citraconic acid, as well as monoesters of these dicarboxylic acids with monohydric alcohols; unsaturated carboxylic acids; the above α,β-ethylenically unsaturated hydroxyalkyl esters and maleic acid, succinic acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, benzenetricarboxylic acid, benzenetetracarboxylic acid, carboxyl group-containing vinyl monomers, such as ``Himic acid'' (product of Hitachi Chemical Co., Ltd.), adducts of polycarboxylic acids such as tetrachlorophthalic acid or dodecynylsuccinic acid with anhydrides; or vinyl monomers obtained in this manner. Monomers and monoglycidyl esters or butyl glycidyl ethers of monohydric carboxylic acids such as "Carduura E" (glycidyl esters of branched synthetic resin acids manufactured by Siel, Netherlands), coconut oil fatty acid glycidyl esters or octylic acid glycidyl esters. , adducts with monoepoxy compounds such as ethylene oxide or propylene oxide; methylol group-containing compounds such as N-methylol acrylamide, hydroxyl group-containing vinyl monomers such as hydroxyethyl vinyl ester; or glycidyl (meth)acrylate, (β-methyl ) glycidyl (meth)acrylate, (meth)allyl glycidyl ether, or a hydroxyl group-containing vinyl monomer such as α,β-ethylenically unsaturated carboxylic acid or mono-2-(meth)acryloyloxymonoethyl phthalate as described above; "Epicron 200, 400, 850 or 1050" for various unsaturated carboxylic acids such as equimolar adducts with polycarboxylic acid anhydrides such as
[Epoxy resin manufactured by Dainippon Ink and Chemicals Co., Ltd.]
"Epicote 828, 1001 or 1004" (epoxy resin manufactured by Schiel in the Netherlands), "Araldite
6071 or 6084” (epoxy resin manufactured by Ciba Geigy, Switzerland) or “Chitsonox 221”
Adducts obtained by adding various epoxy compounds (epoxy resins) such as [epoxy resin manufactured by Chitsuso Co., Ltd.]; and (meth)acrylamide,
N,N-dimethyl(meth)acrylamide, N
- Carboxylic acid amide group-containing monomers such as alkoxymethylated (meth)acrylamide, diacetone (meth)acrylamide or N-methylol (meth)acrylamide; p-styrenesulfonamide, N-methyl-p-styrene Sulfonamide or N,N-dimethyl-p
- Monomers containing sulfonic acid amide groups such as styrene sulfonamide; N, such as N,N-dimethylaminoethyl (meth)acrylate or N,N-diethylaminoethyl (meth)acrylate;
Activities capable of reacting with acid anhydride groups such as N-dialkylaminoalkyl (meth)acrylates, polycarboxylic acid anhydrides (acid anhydride group-containing monomers) as mentioned above, and N,N-dimethylaminopropylamine. Tertiary amino group-containing monomers such as adducts with compounds having both a hydrogen group and a tertiary amino group; cyano group-containing monomers such as (meth)acrylonitrile; or general formula [However, R ₁ in the formula is a hydrogen atom or a methyl group,
R ₂ or R ₃ represents a hydrogen atom, a C ₁ to C ₈ alkyl group, an aryl group, or a C ₇ to _{C 12} aralkyl group, and A represents a C ₁ to _{C 14} alkylene group. ] Dialkyl [(meth)acryloyloxyalkyl] phosphates or (meth) represented by
Acryloyloxyalkyl acid phosphates; or general formula [R ₁ , R ₂ , R and A in the formula are as described above. ] Dialkyl [(meth)acryloyloxyalkyl] phosphites or (meth) represented by
Examples include acryloyloxyalkyl acid phosphites, and alkylene oxide adducts of the above-mentioned (meth)acryloyloxyalkyl acid phosphates or acid phosphites; or glycidyl (meth)acrylate and methyl Glycidyl (meth)
Examples include esterification products of the above-mentioned epoxy group-containing vinyl monomers such as acrylates, and phosphoric acid or phosphorous acid, or acidic esters thereof. When carrying out the method of the present invention, the unsaturated monomers listed above are often used in combination from the viewpoint of performance as a fuel (composition). Furthermore, the side chain represented by the above-mentioned structural formula [ ] present in the molecule of the hydroxyl group-containing copolymer (A) is based on ε-caprolactone, and through modification with this ε-caprolactone, the copolymer is (A) is introduced into the molecule of the copolymer (A), and the presence rate of such side chains is 5 to 60% by weight based on the total amount of the copolymer (A);
A suitable range is preferably 10 to 50% by weight. If it is less than 5% by weight, the flexibility and impact resistance at low temperatures of the resulting coating will decrease, while if it exceeds 60% by weight, the hardness and impact resistance of the resulting coating will decrease. Both are unfavorable because chemical resistance and the like will deteriorate. Furthermore, the number average molecular weight of the hydroxyl group-containing copolymer (A) is suitably within the range of 7,000 to 20,000; if it is less than 7,000, the resulting coating film tends to have insufficient weather resistance; Exceeding the above is undesirable since the finished appearance during painting will deteriorate. Furthermore, the Tg of the hydroxyl group-containing copolymer (A) measured by a dilatometer is -40°C to 0
It is necessary to ensure that the temperature is within the range of -40℃.
When using a copolymer with a Tg lower than °C,
The hardness of the coating film becomes insufficient, and the weather resistance also decreases.Conversely, if the temperature exceeds 0℃, the flexibility and impact resistance of the resulting coating film at low temperatures decreases. Both of these are undesirable because they result in On the other hand, when carrying out the method of the present invention, the curing agent
The aminoaldehyde resin used as (B) is an amino group-containing compound such as melamine, urea, acetoguanamine, benzoguanamine, steroguanamine or spiroguanamine;
A condensation product obtained by reacting an aldehyde compound such as formaldehyde, paraformaldehyde, acetylaldehyde or glyoxal by a conventional method, or a so-called modified product obtained by etherifying each of these condensation products with a monohydric alcohol. In addition to these typical products, any material used for paints can be applied. Furthermore, when carrying out the method of the present invention, the above-mentioned isocyanate compounds can also be used as the curing agent (B), and representative examples include tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate. Aliphatic diisocyanates such as isophorone diisocyanate, methylcyclohexane-2,4-(or 2,6-)
Diisocyanate, cycloaliphatic diisocyanate such as 4,4'-methylenebis(cyclohexyl isocyanate) or 1,3-di(isocyanatomethyl)cyclohexane, or addition of each of these diisocyanates with polyhydric alcohol or low molecular weight polyester, water, etc. products (isocyanate prepolymers), or polymers of each of the diisocyanates listed above, and furthermore, isocyanate binders or (co)polymers of each of the diisocyanates listed above (including oligomers). etc. can be mentioned. Furthermore, polyisocyanates listed above may be blocked with known blocking agents such as methyl ketoxime or caprolactam, depending on the base material and curing conditions.
It can be used as an isocyanate compound. The amount of the aminoaldehyde resin or isocyanate compound to be used as the curing agent (B) is preferably within the range of 10 to 80 parts by weight based on 100 parts by weight of the hydroxyl group-containing copolymer (A). It is. If the amount is less than 10 parts by weight, the coating film tends to be insufficiently crosslinked, resulting in decreased weather resistance, hardness, and solvent resistance.On the other hand, if it exceeds 80 parts by weight, the flexibility and resistance at low temperatures may deteriorate. Both are unfavorable as they result in decreased drug properties. In addition, when carrying out the method of the present invention, other types of hydroxyl group-containing (co-)containing materials, such as those commonly used in this type of thermosetting resin paint, may be used as necessary.
There is no problem in mixing the polymers to form a base coat or clear coat. Typical examples of other hydroxyl group-containing (co)polymers mentioned here include hydroxyl group-containing acrylic resins, alkyd resins, and polyester resins (oil-free, alkyd resins), but these (co)polymers Mainly from the viewpoint of coating film performance, it is desirable to use them in combination whenever necessary. Furthermore, when carrying out the method of the present invention, a curing catalyst can be used if necessary. In that case, when an aminoaldehyde resin is used as the curing agent (B), the curing catalyst may include p-toluenesulfonic acid, dinonylnaphthalenedisulfonic acid, dodecylbenzenesulfonic acid,
Phosphoric acid, phosphoric acid ester, hydrochloric acid, or those whose acid groups are blocked with amines,
It is appropriate to use a dicarboxylic acid such as phthalic acid or halogenated phthalic acid half esterified with a C ₁ to _{C 4} monohydric alcohol (semi-esterified product), and on the other hand, the above-mentioned curing agent
When an isocyanate compound is used as (B), it is appropriate to use dibutyltin diacetate, dibutyltin dilaurate, triethylamine or diethanolamine as the curing catalyst. The amount of the curing catalyst to be used is within the range commonly used for each compound.
In particular, it may be selected appropriately depending on the baking temperature and baking time of the paint. Furthermore, in carrying out the present invention, the aforementioned metallic powder to be blended into the base coat and the aforementioned coloring pigments to be further blended as needed are the same as those used in conventional paints. Typical examples include aluminum powder, copper powder, mica powder, or mica powder coated with titanium oxide as metallic powders, and titanium oxide, carbon black, and cyanine as coloring pigments. There are blue and cyanine green. Furthermore, the base coat or clear coat may contain other commonly known additive components such as plasticizers, antioxidants, ultraviolet absorbers, leveling agents, surfactants, or cellulose esters, if necessary. Of course, this is a good thing. In the method of the present invention, that is, the metallic finishing method using a two-coat one-bake method, first, a base coat containing the above-mentioned hydroxyl group-containing copolymer (A) and a curing agent (B) as essential film-forming components is applied using a known and commonly used method. Adjust the viscosity at 20℃ using a diluting solvent using food cup No. 4 within a range of 10 to 20 seconds, and apply this to a dry film thickness of 10 to 20 seconds on the substrate.
Either directly apply the primer to a thickness of 30 μm, or apply it to a base material where a primer coating has been previously formed so that the dry film thickness is 10 to 30 μm.
Next, after being left at room temperature for several minutes (setting), a clear coat containing the above-mentioned hydroxyl group-containing copolymer (A) and curing agent (B) as essential film-forming components was applied to a food cup No. 1 at 20°C. Adjust the viscosity according to .4 to be within the range of 20 to 40 seconds,
The dry film thickness is
After applying multiple coats to a thickness of 20 to 50 μm, and then allowing it to stand at room temperature for several minutes (setting), it is cured at a temperature of 60 to 180 °C when aminoaldehyde resin is used as the curing agent (B). , on the other hand,
When using isocyanate compounds, the temperature ranges from room temperature to
It is baked at a temperature of 140° C. for 10 to 40 minutes, and in this way the metallic finish that is the object of the present invention is achieved. At that time, RIM is a typical base material.
Urethane or glass fiber reinforced RIM urethane,
Various elastic plastics such as polypropylene modified with rubber, polycarbonate modified with rubber, ABS-polycarbonate or RIM nylon, unsaturated polyester as SMC or BMC, glass fiber reinforced nylon, glass fiber reinforced polybutylene terephthalate or ABS. There are various types of rigid plastics such as resins. Furthermore, typical coating methods that can be used to carry out the method of the present invention include spray coating and electrostatic coating. [Example] Next, the present invention will be specifically explained using reference examples, examples, and comparative examples. In the following, all parts and percentages are based on weight unless otherwise specified. Reference Example 1 [Preparation example of hydroxyl group-containing copolymer (A)] In a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas inlet tube, 800 g of xylene was added.
200 parts of butyl acetate and 134 parts of ε-caprolactone were charged and heated to 120°C. 20 parts of di-tert-butyl peroxide
A mixture of 10 parts and 2 parts of azobisisobutyronitrile was added dropwise over 5 hours. After the dropwise addition was completed, the reaction was continued by maintaining the same temperature for 4 hours, then 0.1 part of zinc salt of acetylacetone was added to the system, and the reaction was further continued at the same temperature for 8 hours to obtain the desired compound. A solution of polymer (A) was obtained. The Tg of the copolymer (A) thus obtained was -20°C, and the number average molecular weight ( _o ) of the copolymer (A) measured by osmotic pressure was 15,000. Hereinafter, this will be abbreviated as copolymer (A-1). Reference Example 2 [Example of Preparation of Hydroxyl Group-Containing Copolymer (A)] Into the same reactor as in Reference Example 1, 800 parts of xylene and 200 parts of butyl acetate were charged and heated to 120°C, and 200 parts of methyl methacrylate was charged. parts, 500 parts of ethyl acrylate, 280 parts of "TONE M-100" (a hydroxyl group-containing monomer derived from ε-caprolactone, manufactured by Union Carbide, USA), 20 parts of acrylic acid, di-tert -butyl peroxide 10
A mixture of 1 part and 2 parts of azobisisobutyronitrile was added dropwise over 5 hours, and the reaction was continued by maintaining the same temperature for an additional 5 hours after the dropwise addition was completed. A solution of the desired copolymer (A) having , and _o of 13,000 was obtained. Hereinafter, this will be abbreviated as copolymer (A-2). Reference Example 3 [Example of preparation of hydroxyl group-containing copolymer (A)] The same procedure as in Reference Example 1 was carried out, except that the raw material composition was changed as shown below, and Tg was -16°C and _o was 16000.
A solution of copolymer (A) was obtained. ε-caprolactone 270 parts Methyl methacrylate 150 Ethyl acrylate 210 N-butyl acrylate 200 2-hydroxyethyl acrylate 150 Acrylic acid 20″ 1000 Reference example 4 [Hydroxyl group-containing copolymer (A) Preparation Example] In a reactor similar to Reference Example 1, "Swazol #1000" [aromatic hydrocarbon mixture manufactured by Maruzen Oil Co., Ltd.]
700 parts of styrene, 300 parts of butyl acetate, and 150 parts of ε-caprolactone were heated to 120°C, and 100 parts of styrene, 200 parts of n-butyl methacrylate,
380 parts of 2-ethylhexyl acrylate, 150 parts of 2-hydroxyethyl acrylate, 20 parts of acrylic acid, 10 parts of di-tert-butyl peroxide.
A mixture of 1 part and 4 parts of azobisisobutyronitrile was added dropwise over a period of 5 hours, and after the addition was completed, the same temperature was maintained for another 4 hours, and then 0.1 part of zinc salt of acetylacetone was added to the system. The reaction was continued by maintaining the same temperature for 5 hours, and a solution of the desired copolymer (A) with a Tg of -28°C and an _o of 10,000 was obtained. Hereinafter, this will be referred to as a copolymer (A-
4). Reference Example 5 [Example of Preparation of Hydroxyl Group-Containing Copolymer (A)] Into the same reactor as in Reference Example 1, 700 parts of "Swazol #1000" and 300 parts of butyl acetate were charged, heated to 120°C, and styrene 100 parts of n-butyl methacrylate, 200 parts of lauryl acrylate, 300 parts of "TONE M-100", 20 parts of methacrylic acid, 10 parts of di-tert-butyl peroxide.
A mixture consisting of 1 part and 4 parts of azobisisobutyronitrile was added dropwise over 5 hours, and the reaction was continued by maintaining the same temperature for 5 hours after the dropwise addition was completed.
Target copolymer with Tg-25℃ and _o of 11000
Solution (A) was obtained. Hereinafter, this will be described as a copolymer (A
-5). Reference Example 6 [Example of preparation of hydroxyl group-containing copolymer for comparison] The same procedure as Reference Example 2 was carried out except that the unsaturated monomer composition was changed as shown below, and the Tg was -18 °C, and
A solution of a control copolymer having an M _o of 14,000 was obtained. Methyl methacrylate 180 parts Ethyl acrylate 500 n-butyl acrylate 150 2-hydroxyethyl acrylate 150 acrylic acid 20'' 1000 Hereinafter, this will be abbreviated as copolymer (A'-1). Reference Example 7 [Preparation example of hydroxyl group-containing copolymer for comparison] The same procedure as Reference Example 4 was carried out except that the unsaturated monomer composition was changed as shown below, and the Tg was -30°C, and
A solution of a control copolymer having an M _o of 10,000 was obtained. Styrene 100 parts n-butyl methacrylate 200 Lauryl methacrylate 530 2-hydroxyethyl acrylate 150 Acrylic acid 20 1000 Hereinafter, this will be abbreviated as copolymer (A'-2). Reference Example 8 [Preparation example of a hydroxyl group-containing copolymer for comparison] A control copolymer with a Tg of 5°C and _{an o} of 10000 was prepared in the same manner as in Reference Example 3, except that the raw material composition was changed as shown below. A combined solution was obtained. Styrene 100 parts n-butyl methacrylate 580 2-hydroxyethyl acrylate 150 ε-caprolactone 150 methacrylic acid 20 1000 Hereinafter, this will be abbreviated as copolymer (A'-3). Reference Example 9 [Preparation example of hydroxyl group-containing copolymer for comparison] Except for changing the polymerization initiator composition as shown below,
In the same manner as Reference Example 3, Tg is -30℃ and _o is
A solution of a control copolymer designated 5400 was obtained. Azobisisobutyronitrile 5 parts tert-butylperoxy-2-ethylhexanate 20 Hereinafter, this will be abbreviated as copolymer (A'-4). Reference Example 10 [Example of preparation of hydroxyl group-containing copolymer for comparison] In a reaction vessel equipped with a stirrer, a thermometer, and a water separation device, 40 parts of isophthalic acid and 24.5 parts of adipic acid were added.
1 part, 43 parts of neopentyl glycol and 7 parts of trimethylolpropane to give an acid value of about 8.
Then, heating was continued while removing water in a temperature range of 150 to 230 °C until the Gardner-Holdt viscosity measured at 20 °C was F for a xylene solution with a hydroxyl value of about 100 and a solid content of 60%. . Next, 100 parts of the polyester polyol thus obtained were mixed with 75.5 parts of "Swazol #1000", 32.3 parts of cellosolve acetate and 7.8 parts of hydrogenated xylylene diisocyanate to obtain a reaction mixture, and then this mixture was heated to 80°C for 10 minutes. After heating for an hour, it was cooled to 60°C and 10 parts of n-butanol was added.
Non-volatile content is 50% and Gardner-Holdt viscosity is N-
A solution of a hydroxyl group-containing isocyanate-modified polyester having an acid value of 3.7 was obtained. Hereinafter, this will be abbreviated as copolymer (A'-5). Examples 1 to 5 and Comparative Examples 1 to 5 First, hydroxyl group-containing copolymers (A-1) to (A-3) and (A'-1) obtained in Reference Examples 1 to 3 and Reference Example 6, etc. Using a diluting solvent, mix at the composition ratio shown in Table 1.
Viscosity by food cup #4 at °C is 13~
It was adjusted to 14 seconds and used as a base coat.

[Table] Next, Reference Examples 4, 5, 6, 7, 8, 9 and 10
Copolymers (A-4), (A-5), obtained in
(A'-2), (A'-3), (A'-4) and (A'-
5) etc., in the composition ratio shown in Table 2, and then adjusted with a diluting solvent so that the viscosity of the food cup #4 at 20°C is 255 to 27. I did it. Using each of the base coats thus obtained, spray painting was carried out in a conventional manner, and after being left at room temperature for 3 minutes, a clear coat was applied and cured under the conditions shown in Table 3. The spray conditions for such painting are a discharge pressure of 4
Kg/cm ² and the discharge amount was 400 ml/mm, and the base coat and clear coat thicknesses were approximately 20 μm and approximately 20 μm, respectively.
This was done so that the thickness was 30 μm. The results of a comparison of various performances of the respective cured coating films thus obtained are summarized in Table 3.

【table】

【table】

〔Effect of the invention〕

As is clear from the results shown in Table 3,
It is known that the metallic finish coating obtained according to the method of the present invention is excellent in appearance, durability, chemical resistance, flexibility at low temperatures, and weather resistance in a well-balanced manner.

Claims (1)

[Scope of Claims] 1. A paint (base coat) containing a thermosetting resin as a base resin component (film-forming component), which is a mixture of metallic powder and a coloring pigment if necessary, is applied, and then this coating is applied. In the metallic finishing method, which consists of applying a paint (clear coat) containing the same thermosetting resin as the base resin component (film-forming component) to the painted surface, and then curing it by heating, the above-mentioned base coat and Each of the essential resin components of the clear coat has (A) a structural formula in the molecule. [However, n in the formula shall be an integer of 1 or 2 or more. ] Contains a side chain represented by 5 to 60% by weight,
Moreover, a hydroxyl group-containing copolymer having a number average molecular weight of 7,000 to 20,000 and a glass transition point of -40°C to 0°C, and (B) a curing agent, are 100% of the hydroxyl group-containing copolymer (A). It is characterized in that the mixture is used in a ratio of 10 to 80 parts by weight of the curing agent (B) to parts by weight. Metallic finishing method. 2. The method according to claim 1, characterized in that the curing agent (B) is an aminoaldehyde resin. 3. The method according to claim 2, wherein the curing agent (B) is an isocyanate compound.