CA2219303A1 - Method for formation of multi-layer coating film - Google Patents
Method for formation of multi-layer coating film Download PDFInfo
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- CA2219303A1 CA2219303A1 CA002219303A CA2219303A CA2219303A1 CA 2219303 A1 CA2219303 A1 CA 2219303A1 CA 002219303 A CA002219303 A CA 002219303A CA 2219303 A CA2219303 A CA 2219303A CA 2219303 A1 CA2219303 A1 CA 2219303A1
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- coating
- color base
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D1/00—Processes for applying liquids or other fluent materials
- B05D1/36—Successively applying liquids or other fluent materials, e.g. without intermediate treatment
- B05D1/38—Successively applying liquids or other fluent materials, e.g. without intermediate treatment with intermediate treatment
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/50—Multilayers
- B05D7/56—Three layers or more
- B05D7/57—Three layers or more the last layer being a clear coat
- B05D7/577—Three layers or more the last layer being a clear coat some layers being coated "wet-on-wet", the others not
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- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
- Paints Or Removers (AREA)
Abstract
A method of multilayer coating, comprising the steps of applying a cationic electrodeposition paint to a metallic object, heating and curing the paint, applying a first color base coat for covering the metallic surface, applying a second color base coat having transparency on the first coat before it is substantially cured, heating and curing both of the first and second color base coats, applying then a clear paint, and heating and curing it. According to this method, it is possible to form a multilayer paint coat that shows improvement in appearance, design, decorativeness, corrosion proofness, weatherability, chipping resistance and other physical properties.
Description
.i~i "~ , J~
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l)ESCR I PT I ON
METHOD FOR FORMAT I ON OF MULT I -LAYER l,OAT I NG
FILM
Technical Field The presenl: invention relates to a method for forming a multi-layer coating film, which can be applied at a low cost and whiich can form, on a metal-m;~de sub-10 strate, especially an automobile body panel, a multi-layer coating film superior in finish appearan~_e, aes-thetic e~fect, corrosion resistance, wheatheral~ility, chipping resistance, physical properties, etc.
15 Bac~ground Art Body panels of automobiles, bicycles, electric appliances, etc. wherein fine appearance is an important requirement, have hitherto been subjected to finish coating with an orgar-ic solvent type thermosetting 20 coating capable of forming a coating fi Im superior in smoothness, distinctness of image gloss, weatherability, etc. Usually, the coating process for such a body panel comprises applying a cationic electrocoating for provid-ing of corrosion resistance, then applying an intermedi-ate coating for providing of weatherability and chippingresistance, heat-curing each of the resulting two coat-ing films, applying, as a top coat for providing of aesthetic effect, a thermosetting coating containing a coloring pigment and~'or a metallic pigment (the thermo-setting coating is hereinafter referred to as 'colorbase coating"), air-drying the resulting coating film, then applying thereon a thermosetting clear coating, and heat-curing the formed two coating films simul-taneously (this coating steps is a so-called two-coat one-bake 35 method).
In recent years, the requirements for resource ~ CA 02219303 1997-10-24 saving, reduction in number of operational steps, pollu-tion control and lower applica~ion cost have bc~come stronger. Hence, it is desired to develop a coating method not requiring the step for application of inter-mediate coating.
D i sc I osure of the I n~ent i on The present inventors made an intensive study with an aim of developing a coating ~ethod whinvh can be 10 applied at a low coslt, which can form a coating film greatly superior in 'Finish appearance, aesthetic effect, corrosion resistance, weatherability, chipping resist-ance, etc., and which is advantageous in resource saving and pollution control.
As a resul1t, the present inventors found out that the above aim can be achieved using no in-termediate coating, by using a cationic electrocoating, two kinds of color base coatings of different functions, and a clear coating. The present invention has been completed 20 based on the.finding Thus, according to the present inven-tion, = there is provided a rnethod for forming a multi-layer coating film, which iis characterized by applyil1g a cationic electrocoatiing (A) on a metal-made material to 25 be coated, heat-curing the resulting electrocoating film, applying, on the heat-cured electrocoating fiIm, a first color base coat~ing (B) having a sublayer--hiding powder, applying, on the resulting coating film without substantially curing the film, a second color l~ase 30 coating (C) having transparency, heating the two fiIms of the first color base coating and the second color base coating to cure them, then applying a clear coating (D), and heat-curing the resulting clear coating film.
The feature of the present invention lies in 35 that the two color base coatings (B) and (C) both as top coat can be applied on the film of an ordinary cationic ~ CA 02219303 1997-10-24 e~ectrocoating by a -two-coat one-bake method, without applying an ordinary intermediate coating on said fiIm.
In the present method, the top coat is di-rectly applied on the baked and cured fiIm of a cationic electrocoating without applying an intermediate coating on said fiIm; nevertheless, it has been found that there occurs 110 weather-in~uced peeling (the weather-induced peeling is a phenomenon in which a light passes through a top coat fiIm and photochemically deterioratl~s an 10 electrocoating film as sublayer and, as a result, inter-coat adhesion failure occurs between the two fiIms during outdoor exposure) because the first color base coating (B) has a sublayer-hiding power. Moreover, according to the pre~;ent method, here can be obtained an advantage that the application cost of can be made lower because the step of app I y i ng an intermediate coating can be eliminated.
The presenl: method also has a feature that sin~e the second color base coating (C) has a color and 20 transparency, the coating fiIm obtained can have excel-lent finish appearance of fattiness, smoothness, dis-tinctness of image gloss, depth feeling, high luster, strong metallic feeling, no mottling, etc.
Therefore, combined use of the first color 25 base coating (B) and the second color base coating (C) according to the present invention enables forr1ation of a novel multi-layer c:oating film having an aesthetic effect which has been uncbtainable heretofore.
The present method has a further advantage 30 tha-t since a clear coating is applied on the heat-cured fiIm of the color bas;e coating, there can be used, as the clear coating, a clear coating of any type such as solvent type, aqueous' type, powder type or the like.
The coating method of the present invention is hereinafter describecl in more detail.
.. .
' Metal-made material to be coated There is no particular restriction as to the material to be coated according to the present method, as long as the material is a metal product to ~hich cationic electrodeposition is applicable. As the mate-rial to be coated, tl~ere can be mentioned, for example, iron, copper, aluminum, tin, zinc, other metals, alloys containing these metals, and articles which are plate~
or vapor-deposited with these metals. Specific examples 10 of the rnaterial to be coated include body panels of automobiles such as passenger cars, trucks, autobicy-cles, buses and the like, formed using members made of the above metals. Preferably, these materials to be coated are beforehand subjected to a chemical treatment 15 with a phosphoric acid salt, a chromic acid salt or the = like.
Cationic electrocoatin~ (A) The cationic electrocoating (A) used in the present method is a coating to be directly applied on 20 the above-mentioned nnetal-made material to be coated.
There is no strict restriction as to the type of the cationic electrocoating (A), and there can be used one of various cationic electrocoatings which are Icnown per se. Specific examples of the cationic electrocoating (A) include coatings which contain, as a main component, a water-soluble or water-dispersible resin obtained by neutralizing, with a neutralizing agent, a resin having a base value of generally about 30-200, such as epoxy resin, acrylic resin, polybutadiene resin or the like (all of these resins are modified with an amino group-containing compound) and which further contain, as necessary, a crosslinking agent (e.g. a blocked polyiso-cyanate or an alicyclic epoxy resin), a coloring pig-ment, a rust-preventive pigment, an extender pigrnent, a hydrophilic organic solvent, etc. As the neutralizing agent, there can be used, for example, an organic acid .
such as acetic acid, hydroxylacetic acid7 propionic acid, bu-tyric acid, lactic acid, glycine or th,e like; or an inorganic acid such as sulfuric acid, hydrochloric acid, phosphoric acid or the like. The amount o~ the neutralizing agent used is appropriately about 0.1-0.4 in terms of neutralization equivalent relative to the base value of the resin.
The ~ationiic electrocoating (A) is diluted with a deionized water or the like so that the solid 10 content becomes abou~t 5-40% by weight, preferably about 10-30% by weight; an~ can be electrodeposited by an ordinary method with the pH being kept at 5-8, prefera-bly ~.5-7. The resulting coating fiIm can be cured at about 140-210~C, prelFerably at about 160-190~C The 15 thickness of the coaiting fiIm is preferably about 10-60 ~m, part;cularly abolJt 15-40 ~m as cured.
First color base coatin~ (B) The first <,olor base coating (B) is ;3 coating to be applied on the heat-cured film of the above-men-20 tioned cationic electrocoating and has a subla~er-hiding power. There is no strict restriction as to the type of the first color base coating (B), and there can be used, for example, a per se known thermosetting coating of aqueous type or organic solvent type, containing a base 25 material resin, a curing agent, a pigment and water and/or an organic sollvent.
The base material resin constitutes -the main component of the coating fiIm formed by the first color base coating (B) and is appropriately a resin for coat-ing which is excellent in weatherability, transparency, etc. and which is soluble or dispersible in wa-ter or organic solvents. There can be mentioned, for example, an acrylic resin, a polyester resin, an epoxy resin and a urethane resin.
As the acrylic resin, there can be mentioned, for example, a resin having an acid value of about 0-100, preferably abou~ 5-30 and a hydroxyl value of about 20-200, preferably about 40-120, which is obtained by copolymerizing an a,~3-ethylenically unsaturate~ car-boxylic acid, a func~tional group (e.g. hydroxyl group, amide group or methylol group)-containing (meth)acrylic acid ester, and other copolymerizable monomer(s) [e.g.
functional group-free (meth)acrylic acid ester, substi-tuted or unsubstituted styrene andJor olefin).
As the polyester resin, there can be used a resin obtained by subjecting a polybasic acid, a poly-hydric alcohol and a modified oil to ordinary ~ondensa-tion. As the epoxy resin, there can be mentioned, for example, an epoxy eslter resin obtained, for ex,~mple, by a process which comprises reacting epoxy group with an 15 unsatura-ted fatty acid to synthesize an epoxy ester and adding an ~,~-unsaturated acid to the unsaturated group of the epoxy ester, or by a process which comprises esterifying the hydroxyl group of epoxy ester INi th a polybasic acid such as phthalic acid or trimellitic 20 acid.
As the urethane resin, there can be mentioned a high-molecular resin obtained by reacting thle above-mentioned acrylic resin, polyester resin or epoxy resin with a diisocyanate compound. The resin is us~ed mainly 25 as a water-dispersible resin.
When an aqueous type coating is used as the first color base coating (B), there can be useld, as the base material resin 1thereof, a resin having a !hydro-philic group (for example, a carboxyl group, a hydroxyl 30 group, a methylol group, an amino group, a sulfonic acid group or a polyoxyethylene bond, most typically a car-boxyl group) of an arnount sufficient to make t!he resin water-soluble or water-dispersible. The resin can be made water-soluble or water-dispersible by neutralizing 35 the hydrophilic group to convert it into an allkali salt.
In that case, the amount of the hydrophilic grDup (for CA Oi219303 1997-10-24 .
example, carboxyl group) is not particularly restricted and can be appropria~tely determined depending ~pon to what extent the resin is made water-soluble or water-dispersible; however, the amount can be generally about 10 or more, preferabily 10-100, more preferably 15-50 in terms of acid value. As the aIkaline substance used for neutralization, there can be mentioned, for example, sodi um hydroxide and various amines.
The base material resin can be made ivater-10 dispersible also by subjecting the above-mentioned monomer components to emulsion polymerization in the presence of a surfacl:ant or a water-soluble resin, or by dispersing the base material resin in water in the presence of, for example, an emulsifier. In this method 15 of making water-dispersible the base material resin, the resin need not contain the above-mentioned hydrophilic group, or can contain the hydrophilic group in an amount smaller than that carried by the water-soluble resin.
Meanwhile, when an organic solvent type coat-ing is used as the first color base coating (B), the coating can be prepared by dissolving or dispersing the above-mentioned base material resin (this resin need not contain the hydrophilic group but may contain it) and other coating components in an organic solvent. As the 25 organic solvent, there can be used those ordinarily used in coatings. There can be mentioned, for example, hydrocarbon types such as toluene, xylene, hexane, heptane and the like; ester types such as ethyl acetate, butyl acetate, ethylene glycol monomethyl ether acetate, 30 diethylene glycol monoethyl ether acetate, diet;hylene glycol monobutyl acetate and the like; ether types such as ethylene glycol monomethyl ether, ethylene ~;lycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol dibutyl ether and the like; alcohol 3~ types such as butanol, propanol, octanol, cyclohexanol, diethylene glycol and the like; and ketone types such as ,, ~
methyl ethyl ketone, methyl isobutyl ketone, cyclohexa-none, isophorone and the like.
The form of the organic solvent type coating includes a solution form, a high-solid form, a non-aqueous dispersion f~rm, etc.
The curing agent usable in the first color base coating (B) is to crosslink and cure the base material resin three-dimensionally by heating. Specifi-cally, an amino resin is appropriate which is obtained 10 by subjecting melamine, benzoguanamine, urea or the like to condensation or co-condensation with formaldehyde and, as necessary, subiecting the resulting condensate or co-condensate to, for example, etherification with a lower monohydric alcchol. A polyisocyanate compound or 15 a blocked polyisocyanate compound is also appropriate.
The pigment usable in the first color base coating (B) is to allow the coating fiIm formed by the first CIDl or base coating (B) to have a sublayer-hiding power. Specific examples of the pigment are met~llic 20 pigments such as aluminum powder, bronze powder, copper powder, tin powder, lead powder, zinc powder, iron phosphide, pearl-lik,e metal-coated mica powderr mica-like iron oxide and the like; rust-preventive pigments such as zinc chromat,e, strontium chromate, calcium 25 chromate, lead cyanamide, calcium plumbate, zinc phos-phate and the like; ,coloring pigments such as titanium dioxide, carbon blacLk, Phthalocyanine Blue, Phthalo-cyanine ~reen, Carbazole Violet, anthrapyridine, Azo Orange, Yellow, Flav,anthrone Yellow, Isoindoline Yellow, 30 Azo Yellow, Indanthrone Blue, Di Brom Anthanthron Red, Perylene Red, Azo Red, Anthraquinone Red, Ouinacr;done Red, Violet and the like; and extender pigments such as barium oxide powder, precipitated barium sulfate, barium carbonate, gypsum, clay, silica, white carbon, diato-35 maceous earth, talc, magnesium carbonate, alumina white,gloss wh i te, satin white, mica powder and the like.
~ CA 02219303 1997-10-24 ~. .
These pigments can be used singly or in combination of two or more kinds.
Desirably, the first color base coating (B) contains, as the pigment component, a metallic pigment and/or a coloring pigment selected from the above-men-tioned pigments.
The first color base coating (B) can further contain a dye. as necessary. Desirably, the dye is one superior in light resistance, solubility in water and 10 organic solvent, etc. As specific examples of the dye, there can be mentioned azo dyes such as monoazo dye, polyazo dye, metal complex azo dye, pyrazolone azo dye, stilbene azo dye and thiazole azo dye; anthraquinone dyes such as anthraquinone derivative and anthrone 15 derivative; indigoid dyes such as indigo derivative and thioind;go derivative; phthalocyanine dyes; carbonium dyes such as diphenylmethane dye, triphenylmethane dye, xanthene dye and acridine dye; quinoneimine dyes such as azine dye, oxazine d!~e and thiazine dye; methine dyes 20 such as polymethine (or cyanine) dye and azimethine dye;
quinoline dyes; nitro dyes; nitron dyes; benzol~uinone or naphthoquinone dyes; naphthalimide dyes; and Perinone dyes. ~hese dyes can be used singly or in combination of two or more kinds.
The proporl:ions of the above individual compo-nents in the first color base coating (B) are not strictly restricted and can be determined appropriately depending upon, for example, the purpose of the use of the coated article. However, the preferable proportions 30 of the base material resin and the curing agent are 60-90% by weight, partic:ularly 70-8~Yo by weight (i:he for-mer) and 40-10% by we! ight, particularly 30-1~% by weight (the latter) based on the total weight of the l:wo compo-nents.
The pigment can be used in an appropriate combination depending; upon the desired level of sub-layer-hiding power, the desired color of the base coat-ing (B), etc. The suitable amount of the pigment used is such that the transmittance of light having a wave-length within a range of 400-700 nm of a cured fi Im of 30 ~m in thickness which was formed from the first color base coating is generally 5% or less. preferably 3% or less. The specific amount of the pigment used differs depending upon the kind of the pigment and cannot be determined in a particular range, but can be generally 1-250 parts by weight, preferably 5-150 parts by weight per 100 parts by weight of the resin solid content (the total amount of the base material resin and the curing agent).
Incidentally, in the present specification, 15 the light transmittance of coating fiIm is an avèrage spectral transmittance obta;ned when a coating is ap-plied on a glass shelet so as to give a fiIm of particu-lar thickness as cur,ed, the resulting coating fi Im is cured, the resulting material is immersed in a hot water 20 of 60-70~C, the coating fiIm is peeled from the glass sheet and dried, and the dried fiIm is subjected to measurement by a recording spectrophotometer (Model EPS-3T, a product of Hit;achi, Ltd.) using a light having a wavelength of 400-700 nm.
The first color base coating (B) can be ap-plied according to an ordinary method. The coating (B) can be applied, for Isxample, by adding, to the coating, deionized water and/or an organic solvent and, as neces-sary, a~ditives such as thickener, antifoaming agent and 30 the like to adiust the solid content to 10-70% by weight, preferably 1~ 5% by weight and the viscosity to 10-60 seconds, particularly 12-30 seconds (Ford Cup #4/20~C~ in the case of a solvent type coating and to 200-5,000 cp/6 rpm, I~articularly 300-3,000 cp/6 rpm (B
35 type viscometer) in ~the case of a water-soluble or water-dispersible coating, and applying, by spray coat-ing or the like, the resulting material on the cured coating fiIm of the cationic electrocoating (A) so as to form a coating fiIm of, for example, about 5-60 ~m, preferably about 8-2!5 ~m in thickness as cured. In the present method, it ;!S preferred that the first color base coating (B) is applied, the resulting coating film is air-dried at room temperature by air blowing or the like without substan-tially curing the fiIm, and then the second color base co;ating (C) is applied.
10 Second color base C0;3ti n~ (C) The color base coating (C) is a coating to be applied on the film of the first color base coating (B) and has transparency. The kind of the coating (C) is not strictly restricted. As the coating (C), there can 15 be used a per se kno~Nn thermosetting coating of aqueous type or organic solvent type containing a base material resin, a curing agen-t, a pigment and water and./or an organic solvent.
Each individual component of the coating (C) 20 can be selected from the specific examples of each component mentioned in the first color base coating (B).
The second color base coating (C) can as weli contain a dye as necessary. As the dye, there can be used at least one of the specific examples mentioned in 25 the first color base coating (B).
In the second color base coating (C), the proportions of the individual components are not strictl~ restricted and can be determined appropriately depending upon the purpose of the use of the coated 30 article. However, the proportions of the base material resin and the curing agent can be generally 60--90% by weight, particularly 70-85% by weight (the forrner) and generally 40-10% by ~eight, particularly 30-15'~ by weight (the latter) all based on the total weight of the 35 two components.
The second color base coating (C) preferably .. ~
contains, as the pign1ent component, a metallic pigment and/or a coloring pig~ment. Desirably, the total content of the pigment is relatively low so that the film formed by the second color base coating (C) can have transpar-ency and the color of the first color base coating canbe seen through said film. It is generally pr~erable that the total content of the pigment is lower than the total content of the pigment in the first color base coating (B).
Specifically, the desired amount of the pig-ment used is such that the transmittance of li~,ht having a wavele~gth within a range of 400-700 nm of a cured fiIm of 30 ~m in thickness which was formed from the second color base coating is 6-95%, particularly 10-90%, 15 more particularly 20-80% The amount o~ the pigment used differs depending upon the kind of the pigment and cannot be specified in a particular range; however, it is preferable that the amount is generally 0,01-100 parts by weight, particularly 0.1-80 parts by weight per 100 parts by weight of the resin solid content (the total amount of the base material resin and the curing agent) and that the amount is smaller than that in the first color base coating (B).
The second ~_olor base coating (C) can be 25 applied according to an ordinary method. The coating (C) can be applied, for example, by adding, to the coating, deionized wa-ter and/or an organic solvent and, as necessary, additives such as thickener, antifoaming agent and the like to adjust the sol;d content -to 1O-7O~D
30 by weight, preferably 20-60% by weight and the viscosity to 10-60 seconds, particularly 13-40 seconds (Ford Cup ~4/20~C) in the case of a solvent type coating and to 200-~,000 cp/6 rpm, particularly 300-3,000 cp/6 rpm ~B
type viscometer) in the case of a water-soluble or 35 water-dispersible coat:ing, and apply;ng, by spray coat-ing or the like, the resulting material so as to form a -coating fiIm of, for example, about 10-70 ~m, particu-larly about 15-50 ~m in thickness as cured. In the present method, it is preferred as mentioned previously that the first color base coating (B) is applied, the resulting coating fiIm is air-dried at room temperature by air blowing or the like withou~ substantially curing the fiIm, and then the second color base coatil1g (C) is applied. After the appl ication of the second color base coating (C), heating is conducted at a temperature of 10 about 80-170~C, prefe~rably about 120-160~C for about 3-40 minutes, preferablly about 10-30 minutes, whereby the first color base coaling (B) and the second color base coating (C) can be cured simultaneously. For the heat-ing, there can be used a method ordinarily use~, such as hot-air heating, infrared heating, high-frequency heat-ing or the like.
Clear coatin~ (D) According 1:o the present invention, é~ clear coating ~D) can be applied on the film of the second 20 color base coating ((') so that the multi-layer coating fiIm formed is further improved in aesthetic e1fect, finish appearance, weat-herability, chemical resistance, water resistance, moisture resistance, etc. As the clear coating (D), there can be used a coating capable 25 of forming a colorless or color transparent fiIm.
Specifically, there c:an be used a per se known thermo-setting coating of walter-soluble or water-dispersible type, organic solvent: type or powder type, cont:aining a base material resin alnd a curing agent as the main 30 components and furthe~r containing, as necessary, a coloring pigment, a metallic pigment, a dye, et;c. in such amounts that the~ transparency of the coating fiIm formed is not substamt;ally impaired.
The base material resin and curing aeent usable in the water-soluble or water-dispersible coating and the organic solvent type coating, and the organic ~ CA 02219303 1997-10-24 solvent usable in the organic solvent type coa-ting can be selected from the specific examples mentione~d in the first color base coating (B). The proportions of the base material resin and the curing agent are preferably those also mentioned in the first color base coating.
The water-soluble or water-dispersible clear coating or the organic solvent type clear coating can be applied according to an ordinary method, by adding, to the coating, deionized water and/or an organic solvent 10 and, as necessary, aclditives such as thickener, anti-foaming agent and the like to adjust the sol;d content to about 10-9~% by wei ght, preferably about 30--80% by weight and the viscosity to 10-70 seconds, pre1~erably 15-40 seconds (Ford Cup #4/20~C) in the case ol: a sol-15 vent type coating ancl to 200-5,000 cp/6 rpm, preferably 300-3,000 cp/6 rpm (E~ type viscometer) in the case of a water-soluble or water-dispersible coating, and apply-ing, by spray coating: or the like, the resulting mate-rial so as to form a coating fiIm of, for exam~le, about 10-70 ~m, particularly about 15-50 ~m in thickness as cured. The coating fiIm formed can be cured by heating at a temperature of about 80-170~C, preferably about 120-t60~C for about 20-40 minutes. For the heating, there can be used a method ordinarily used, suc:h as hot-25 air heating, infrared heating, high-frequency heating or the like.
Meanwhile, the powder coating usable as the clear coating (D) is composed mainly of a base material resin and a curing agent as the main components. As the 30 base material resin, there can be mentioned, for exam-ple, an acrylic resin, a polyester resin, a fluoro-plastic, an urethane resin and their modifications (e.g.
a graft polymer) all having at least one crosslinkable functional group selected from hydroxyl group, carboxyl 3~ group, glycidyl group, etc. These resins are merely illustrations and the base material resin is not re-~ CA 02219303 1997-10-24 stricted thereto. The base material resin preferably has a glass transition temperature of generally 40~C or more, particularly 50-120~C, more particularly 6~-100~C.
There is no particular restriction as to the composi-tion, molecular weight, etc. of the base material resin,and they can be appropriately selected depending ~pon the purpose of the use of the coated article.
The curing agent is a component used to three-dimensionally crosslink and cure the base material resin 10 by heating. As the curing agent, there can be used. for example, an alkoxymethylolmelamine, a blocked polyiso-cyanate compound, an epoxy compound, an isocyanurate compound or an aliphatic dibasic acid.
The proportions of the base material resin and 15 the curing agent are most preferably such that the above-merttioned functional group of the base material resin and the functional group of the curing agent become about equimoliar.
The powder coating may further contain, as 20 necessary, additives for coating, such as fluidity-controlling agent, ultraviolet absorber, light stabi-lizer and the like.
The powder coating can be obtained ordinarily by meIt-kneading the above components, cooling the melt-kneaded material, and grinding it into appropriateparticle diameters.
The method by which the powder coatirtg is applied, is not partiicularly restricted, and there can be used an appropriai:e appliGation method for l)owder 30 coating, such as electrostatic spray coating, -Fluidized dip coating or the like.
The fiIm thickness at which the powder coating is applied, is not particularly restricted, ei1her;
however, the fiIm thickness is generally appropriate to 35 be 20-200 ~m. It is preferable to apply the powder coating at a fiIm thickness of particularly 20--120 ~m SQ
as to give a finished coating fiIm superior in smooth-ness, distinctness oIF image gloss, Juster, fattiness, etc. The curing tem~)erature of the fiIm of the powder coating can be taken at the curing temperature of the powder coating, for example, about 120-180~C, preferably about 130-170~C.
Exam~les The present invention is hereinafter described 10 more specificaIIy by way of ExampIes. In the follow-ings, ~parts" and "%" refer to "parts by weight" and a%
by weight~, respectiveIy.
I. Pre~aration of samoIes 1) Cationic eIectrocoatin~ (A) (A-1) "Electron ~g200"(product of Kansai Paint Co., Ltd., trade name, poIyamine-modified epoxy resin-blocked poIyisocyanate type) was diluted with deionizel~ water or the Iike so as to give a soIid content of about t6% by 20 weight. The resuIting material was eIectrodeposited by an ordinary method whiIe the pH was maintained at 5.5-8Ø The thickness of the coatin~ fiIm formed was about 20 ~m in terms of cured fiIm thickness. The coating fiIm was cured at about 175~C.
25 2) Second coIor base coatin~s (B) 50% acrYIic resin soIution (S-1) 30 parts ol: methyI methacryIate, 59 parts of ethyl acryIate, 10 parts of hydroxyethyI acryIate and 1 part of acrylic acid were polymerized by an ordinary 30 process, in the presence of a poIymerization initiator, a, a' -azobisisobutyronitriIe, in a mixed solvent of xyIene/n-butanol = 7()/30, whereby was obtained an acryl-ic resin soIution (S--1 ) having a weight-average moIecu-lar weight of 25,000 and a resin solid content of 50%.
20% aqueous acrvlic resin dis~ersion (W-1) In a reactor were placed 140 parts o-F de-ionized water, 2.5 parts of 30% UNewcol 707SFn (surfac-tant, product of Nipl)on Nyukazai Co., Ltd.) an~ 1 part of a monomer mixture (1) shown below. The reactor contents were stirred in a nitrogen gas current. There-to ~as added 3 parts of a 3% aqueous ammonium persulfate solution at 60~C. The resulting mixture was heated to 80~~. Into the reactor was fed, in 4 hours by the use 10 of a metering pump, a monomer emulsion consisting of 79 parts of the following monomer mixture (1), 2.5 parts of 30% UNewcol 707SF~, 4 parts of a 3% aqueous amlnonium persulfate solution and 42 parts of deionized ~Hater.
The resulting mixture was then subjected to aging for 1 hour. Into the reaclor were dropwise and simultaneously fed, at 80~C in 1.5 hours, 20.~ parts of a monomer mixture (2) shown bellow and 4 parts of a 3% aqueous ammonium persulfate solution. The resulting mixture was then subjected to agiing for 1 hour, then diluted with 30 20 parts of deionized water, and fiItered through a 200-mesh nylon cloth at 30~C. To the fiItrate was added deionized water, and the resulting mixture was adjusted to pH 7.5 using dimethylaminoethanol to obtain a 20%
aqueous acrylic resin dispersion (W-1) having an average 25 particle diameter of 0.1 ~m and a nonvolatile content of 20%.
Monomer mixture (1) Methyl methacrylate 55 part~;
Styrene 10 parts n-Butyl acrylate 9 part~;
.A~;~;L~
l)ESCR I PT I ON
METHOD FOR FORMAT I ON OF MULT I -LAYER l,OAT I NG
FILM
Technical Field The presenl: invention relates to a method for forming a multi-layer coating film, which can be applied at a low cost and whiich can form, on a metal-m;~de sub-10 strate, especially an automobile body panel, a multi-layer coating film superior in finish appearan~_e, aes-thetic e~fect, corrosion resistance, wheatheral~ility, chipping resistance, physical properties, etc.
15 Bac~ground Art Body panels of automobiles, bicycles, electric appliances, etc. wherein fine appearance is an important requirement, have hitherto been subjected to finish coating with an orgar-ic solvent type thermosetting 20 coating capable of forming a coating fi Im superior in smoothness, distinctness of image gloss, weatherability, etc. Usually, the coating process for such a body panel comprises applying a cationic electrocoating for provid-ing of corrosion resistance, then applying an intermedi-ate coating for providing of weatherability and chippingresistance, heat-curing each of the resulting two coat-ing films, applying, as a top coat for providing of aesthetic effect, a thermosetting coating containing a coloring pigment and~'or a metallic pigment (the thermo-setting coating is hereinafter referred to as 'colorbase coating"), air-drying the resulting coating film, then applying thereon a thermosetting clear coating, and heat-curing the formed two coating films simul-taneously (this coating steps is a so-called two-coat one-bake 35 method).
In recent years, the requirements for resource ~ CA 02219303 1997-10-24 saving, reduction in number of operational steps, pollu-tion control and lower applica~ion cost have bc~come stronger. Hence, it is desired to develop a coating method not requiring the step for application of inter-mediate coating.
D i sc I osure of the I n~ent i on The present inventors made an intensive study with an aim of developing a coating ~ethod whinvh can be 10 applied at a low coslt, which can form a coating film greatly superior in 'Finish appearance, aesthetic effect, corrosion resistance, weatherability, chipping resist-ance, etc., and which is advantageous in resource saving and pollution control.
As a resul1t, the present inventors found out that the above aim can be achieved using no in-termediate coating, by using a cationic electrocoating, two kinds of color base coatings of different functions, and a clear coating. The present invention has been completed 20 based on the.finding Thus, according to the present inven-tion, = there is provided a rnethod for forming a multi-layer coating film, which iis characterized by applyil1g a cationic electrocoatiing (A) on a metal-made material to 25 be coated, heat-curing the resulting electrocoating film, applying, on the heat-cured electrocoating fiIm, a first color base coat~ing (B) having a sublayer--hiding powder, applying, on the resulting coating film without substantially curing the film, a second color l~ase 30 coating (C) having transparency, heating the two fiIms of the first color base coating and the second color base coating to cure them, then applying a clear coating (D), and heat-curing the resulting clear coating film.
The feature of the present invention lies in 35 that the two color base coatings (B) and (C) both as top coat can be applied on the film of an ordinary cationic ~ CA 02219303 1997-10-24 e~ectrocoating by a -two-coat one-bake method, without applying an ordinary intermediate coating on said fiIm.
In the present method, the top coat is di-rectly applied on the baked and cured fiIm of a cationic electrocoating without applying an intermediate coating on said fiIm; nevertheless, it has been found that there occurs 110 weather-in~uced peeling (the weather-induced peeling is a phenomenon in which a light passes through a top coat fiIm and photochemically deterioratl~s an 10 electrocoating film as sublayer and, as a result, inter-coat adhesion failure occurs between the two fiIms during outdoor exposure) because the first color base coating (B) has a sublayer-hiding power. Moreover, according to the pre~;ent method, here can be obtained an advantage that the application cost of can be made lower because the step of app I y i ng an intermediate coating can be eliminated.
The presenl: method also has a feature that sin~e the second color base coating (C) has a color and 20 transparency, the coating fiIm obtained can have excel-lent finish appearance of fattiness, smoothness, dis-tinctness of image gloss, depth feeling, high luster, strong metallic feeling, no mottling, etc.
Therefore, combined use of the first color 25 base coating (B) and the second color base coating (C) according to the present invention enables forr1ation of a novel multi-layer c:oating film having an aesthetic effect which has been uncbtainable heretofore.
The present method has a further advantage 30 tha-t since a clear coating is applied on the heat-cured fiIm of the color bas;e coating, there can be used, as the clear coating, a clear coating of any type such as solvent type, aqueous' type, powder type or the like.
The coating method of the present invention is hereinafter describecl in more detail.
.. .
' Metal-made material to be coated There is no particular restriction as to the material to be coated according to the present method, as long as the material is a metal product to ~hich cationic electrodeposition is applicable. As the mate-rial to be coated, tl~ere can be mentioned, for example, iron, copper, aluminum, tin, zinc, other metals, alloys containing these metals, and articles which are plate~
or vapor-deposited with these metals. Specific examples 10 of the rnaterial to be coated include body panels of automobiles such as passenger cars, trucks, autobicy-cles, buses and the like, formed using members made of the above metals. Preferably, these materials to be coated are beforehand subjected to a chemical treatment 15 with a phosphoric acid salt, a chromic acid salt or the = like.
Cationic electrocoatin~ (A) The cationic electrocoating (A) used in the present method is a coating to be directly applied on 20 the above-mentioned nnetal-made material to be coated.
There is no strict restriction as to the type of the cationic electrocoating (A), and there can be used one of various cationic electrocoatings which are Icnown per se. Specific examples of the cationic electrocoating (A) include coatings which contain, as a main component, a water-soluble or water-dispersible resin obtained by neutralizing, with a neutralizing agent, a resin having a base value of generally about 30-200, such as epoxy resin, acrylic resin, polybutadiene resin or the like (all of these resins are modified with an amino group-containing compound) and which further contain, as necessary, a crosslinking agent (e.g. a blocked polyiso-cyanate or an alicyclic epoxy resin), a coloring pig-ment, a rust-preventive pigment, an extender pigrnent, a hydrophilic organic solvent, etc. As the neutralizing agent, there can be used, for example, an organic acid .
such as acetic acid, hydroxylacetic acid7 propionic acid, bu-tyric acid, lactic acid, glycine or th,e like; or an inorganic acid such as sulfuric acid, hydrochloric acid, phosphoric acid or the like. The amount o~ the neutralizing agent used is appropriately about 0.1-0.4 in terms of neutralization equivalent relative to the base value of the resin.
The ~ationiic electrocoating (A) is diluted with a deionized water or the like so that the solid 10 content becomes abou~t 5-40% by weight, preferably about 10-30% by weight; an~ can be electrodeposited by an ordinary method with the pH being kept at 5-8, prefera-bly ~.5-7. The resulting coating fiIm can be cured at about 140-210~C, prelFerably at about 160-190~C The 15 thickness of the coaiting fiIm is preferably about 10-60 ~m, part;cularly abolJt 15-40 ~m as cured.
First color base coatin~ (B) The first <,olor base coating (B) is ;3 coating to be applied on the heat-cured film of the above-men-20 tioned cationic electrocoating and has a subla~er-hiding power. There is no strict restriction as to the type of the first color base coating (B), and there can be used, for example, a per se known thermosetting coating of aqueous type or organic solvent type, containing a base 25 material resin, a curing agent, a pigment and water and/or an organic sollvent.
The base material resin constitutes -the main component of the coating fiIm formed by the first color base coating (B) and is appropriately a resin for coat-ing which is excellent in weatherability, transparency, etc. and which is soluble or dispersible in wa-ter or organic solvents. There can be mentioned, for example, an acrylic resin, a polyester resin, an epoxy resin and a urethane resin.
As the acrylic resin, there can be mentioned, for example, a resin having an acid value of about 0-100, preferably abou~ 5-30 and a hydroxyl value of about 20-200, preferably about 40-120, which is obtained by copolymerizing an a,~3-ethylenically unsaturate~ car-boxylic acid, a func~tional group (e.g. hydroxyl group, amide group or methylol group)-containing (meth)acrylic acid ester, and other copolymerizable monomer(s) [e.g.
functional group-free (meth)acrylic acid ester, substi-tuted or unsubstituted styrene andJor olefin).
As the polyester resin, there can be used a resin obtained by subjecting a polybasic acid, a poly-hydric alcohol and a modified oil to ordinary ~ondensa-tion. As the epoxy resin, there can be mentioned, for example, an epoxy eslter resin obtained, for ex,~mple, by a process which comprises reacting epoxy group with an 15 unsatura-ted fatty acid to synthesize an epoxy ester and adding an ~,~-unsaturated acid to the unsaturated group of the epoxy ester, or by a process which comprises esterifying the hydroxyl group of epoxy ester INi th a polybasic acid such as phthalic acid or trimellitic 20 acid.
As the urethane resin, there can be mentioned a high-molecular resin obtained by reacting thle above-mentioned acrylic resin, polyester resin or epoxy resin with a diisocyanate compound. The resin is us~ed mainly 25 as a water-dispersible resin.
When an aqueous type coating is used as the first color base coating (B), there can be useld, as the base material resin 1thereof, a resin having a !hydro-philic group (for example, a carboxyl group, a hydroxyl 30 group, a methylol group, an amino group, a sulfonic acid group or a polyoxyethylene bond, most typically a car-boxyl group) of an arnount sufficient to make t!he resin water-soluble or water-dispersible. The resin can be made water-soluble or water-dispersible by neutralizing 35 the hydrophilic group to convert it into an allkali salt.
In that case, the amount of the hydrophilic grDup (for CA Oi219303 1997-10-24 .
example, carboxyl group) is not particularly restricted and can be appropria~tely determined depending ~pon to what extent the resin is made water-soluble or water-dispersible; however, the amount can be generally about 10 or more, preferabily 10-100, more preferably 15-50 in terms of acid value. As the aIkaline substance used for neutralization, there can be mentioned, for example, sodi um hydroxide and various amines.
The base material resin can be made ivater-10 dispersible also by subjecting the above-mentioned monomer components to emulsion polymerization in the presence of a surfacl:ant or a water-soluble resin, or by dispersing the base material resin in water in the presence of, for example, an emulsifier. In this method 15 of making water-dispersible the base material resin, the resin need not contain the above-mentioned hydrophilic group, or can contain the hydrophilic group in an amount smaller than that carried by the water-soluble resin.
Meanwhile, when an organic solvent type coat-ing is used as the first color base coating (B), the coating can be prepared by dissolving or dispersing the above-mentioned base material resin (this resin need not contain the hydrophilic group but may contain it) and other coating components in an organic solvent. As the 25 organic solvent, there can be used those ordinarily used in coatings. There can be mentioned, for example, hydrocarbon types such as toluene, xylene, hexane, heptane and the like; ester types such as ethyl acetate, butyl acetate, ethylene glycol monomethyl ether acetate, 30 diethylene glycol monoethyl ether acetate, diet;hylene glycol monobutyl acetate and the like; ether types such as ethylene glycol monomethyl ether, ethylene ~;lycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol dibutyl ether and the like; alcohol 3~ types such as butanol, propanol, octanol, cyclohexanol, diethylene glycol and the like; and ketone types such as ,, ~
methyl ethyl ketone, methyl isobutyl ketone, cyclohexa-none, isophorone and the like.
The form of the organic solvent type coating includes a solution form, a high-solid form, a non-aqueous dispersion f~rm, etc.
The curing agent usable in the first color base coating (B) is to crosslink and cure the base material resin three-dimensionally by heating. Specifi-cally, an amino resin is appropriate which is obtained 10 by subjecting melamine, benzoguanamine, urea or the like to condensation or co-condensation with formaldehyde and, as necessary, subiecting the resulting condensate or co-condensate to, for example, etherification with a lower monohydric alcchol. A polyisocyanate compound or 15 a blocked polyisocyanate compound is also appropriate.
The pigment usable in the first color base coating (B) is to allow the coating fiIm formed by the first CIDl or base coating (B) to have a sublayer-hiding power. Specific examples of the pigment are met~llic 20 pigments such as aluminum powder, bronze powder, copper powder, tin powder, lead powder, zinc powder, iron phosphide, pearl-lik,e metal-coated mica powderr mica-like iron oxide and the like; rust-preventive pigments such as zinc chromat,e, strontium chromate, calcium 25 chromate, lead cyanamide, calcium plumbate, zinc phos-phate and the like; ,coloring pigments such as titanium dioxide, carbon blacLk, Phthalocyanine Blue, Phthalo-cyanine ~reen, Carbazole Violet, anthrapyridine, Azo Orange, Yellow, Flav,anthrone Yellow, Isoindoline Yellow, 30 Azo Yellow, Indanthrone Blue, Di Brom Anthanthron Red, Perylene Red, Azo Red, Anthraquinone Red, Ouinacr;done Red, Violet and the like; and extender pigments such as barium oxide powder, precipitated barium sulfate, barium carbonate, gypsum, clay, silica, white carbon, diato-35 maceous earth, talc, magnesium carbonate, alumina white,gloss wh i te, satin white, mica powder and the like.
~ CA 02219303 1997-10-24 ~. .
These pigments can be used singly or in combination of two or more kinds.
Desirably, the first color base coating (B) contains, as the pigment component, a metallic pigment and/or a coloring pigment selected from the above-men-tioned pigments.
The first color base coating (B) can further contain a dye. as necessary. Desirably, the dye is one superior in light resistance, solubility in water and 10 organic solvent, etc. As specific examples of the dye, there can be mentioned azo dyes such as monoazo dye, polyazo dye, metal complex azo dye, pyrazolone azo dye, stilbene azo dye and thiazole azo dye; anthraquinone dyes such as anthraquinone derivative and anthrone 15 derivative; indigoid dyes such as indigo derivative and thioind;go derivative; phthalocyanine dyes; carbonium dyes such as diphenylmethane dye, triphenylmethane dye, xanthene dye and acridine dye; quinoneimine dyes such as azine dye, oxazine d!~e and thiazine dye; methine dyes 20 such as polymethine (or cyanine) dye and azimethine dye;
quinoline dyes; nitro dyes; nitron dyes; benzol~uinone or naphthoquinone dyes; naphthalimide dyes; and Perinone dyes. ~hese dyes can be used singly or in combination of two or more kinds.
The proporl:ions of the above individual compo-nents in the first color base coating (B) are not strictly restricted and can be determined appropriately depending upon, for example, the purpose of the use of the coated article. However, the preferable proportions 30 of the base material resin and the curing agent are 60-90% by weight, partic:ularly 70-8~Yo by weight (i:he for-mer) and 40-10% by we! ight, particularly 30-1~% by weight (the latter) based on the total weight of the l:wo compo-nents.
The pigment can be used in an appropriate combination depending; upon the desired level of sub-layer-hiding power, the desired color of the base coat-ing (B), etc. The suitable amount of the pigment used is such that the transmittance of light having a wave-length within a range of 400-700 nm of a cured fi Im of 30 ~m in thickness which was formed from the first color base coating is generally 5% or less. preferably 3% or less. The specific amount of the pigment used differs depending upon the kind of the pigment and cannot be determined in a particular range, but can be generally 1-250 parts by weight, preferably 5-150 parts by weight per 100 parts by weight of the resin solid content (the total amount of the base material resin and the curing agent).
Incidentally, in the present specification, 15 the light transmittance of coating fiIm is an avèrage spectral transmittance obta;ned when a coating is ap-plied on a glass shelet so as to give a fiIm of particu-lar thickness as cur,ed, the resulting coating fi Im is cured, the resulting material is immersed in a hot water 20 of 60-70~C, the coating fiIm is peeled from the glass sheet and dried, and the dried fiIm is subjected to measurement by a recording spectrophotometer (Model EPS-3T, a product of Hit;achi, Ltd.) using a light having a wavelength of 400-700 nm.
The first color base coating (B) can be ap-plied according to an ordinary method. The coating (B) can be applied, for Isxample, by adding, to the coating, deionized water and/or an organic solvent and, as neces-sary, a~ditives such as thickener, antifoaming agent and 30 the like to adiust the solid content to 10-70% by weight, preferably 1~ 5% by weight and the viscosity to 10-60 seconds, particularly 12-30 seconds (Ford Cup #4/20~C~ in the case of a solvent type coating and to 200-5,000 cp/6 rpm, I~articularly 300-3,000 cp/6 rpm (B
35 type viscometer) in ~the case of a water-soluble or water-dispersible coating, and applying, by spray coat-ing or the like, the resulting material on the cured coating fiIm of the cationic electrocoating (A) so as to form a coating fiIm of, for example, about 5-60 ~m, preferably about 8-2!5 ~m in thickness as cured. In the present method, it ;!S preferred that the first color base coating (B) is applied, the resulting coating film is air-dried at room temperature by air blowing or the like without substan-tially curing the fiIm, and then the second color base co;ating (C) is applied.
10 Second color base C0;3ti n~ (C) The color base coating (C) is a coating to be applied on the film of the first color base coating (B) and has transparency. The kind of the coating (C) is not strictly restricted. As the coating (C), there can 15 be used a per se kno~Nn thermosetting coating of aqueous type or organic solvent type containing a base material resin, a curing agen-t, a pigment and water and./or an organic solvent.
Each individual component of the coating (C) 20 can be selected from the specific examples of each component mentioned in the first color base coating (B).
The second color base coating (C) can as weli contain a dye as necessary. As the dye, there can be used at least one of the specific examples mentioned in 25 the first color base coating (B).
In the second color base coating (C), the proportions of the individual components are not strictl~ restricted and can be determined appropriately depending upon the purpose of the use of the coated 30 article. However, the proportions of the base material resin and the curing agent can be generally 60--90% by weight, particularly 70-85% by weight (the forrner) and generally 40-10% by ~eight, particularly 30-15'~ by weight (the latter) all based on the total weight of the 35 two components.
The second color base coating (C) preferably .. ~
contains, as the pign1ent component, a metallic pigment and/or a coloring pig~ment. Desirably, the total content of the pigment is relatively low so that the film formed by the second color base coating (C) can have transpar-ency and the color of the first color base coating canbe seen through said film. It is generally pr~erable that the total content of the pigment is lower than the total content of the pigment in the first color base coating (B).
Specifically, the desired amount of the pig-ment used is such that the transmittance of li~,ht having a wavele~gth within a range of 400-700 nm of a cured fiIm of 30 ~m in thickness which was formed from the second color base coating is 6-95%, particularly 10-90%, 15 more particularly 20-80% The amount o~ the pigment used differs depending upon the kind of the pigment and cannot be specified in a particular range; however, it is preferable that the amount is generally 0,01-100 parts by weight, particularly 0.1-80 parts by weight per 100 parts by weight of the resin solid content (the total amount of the base material resin and the curing agent) and that the amount is smaller than that in the first color base coating (B).
The second ~_olor base coating (C) can be 25 applied according to an ordinary method. The coating (C) can be applied, for example, by adding, to the coating, deionized wa-ter and/or an organic solvent and, as necessary, additives such as thickener, antifoaming agent and the like to adjust the sol;d content -to 1O-7O~D
30 by weight, preferably 20-60% by weight and the viscosity to 10-60 seconds, particularly 13-40 seconds (Ford Cup ~4/20~C) in the case of a solvent type coating and to 200-~,000 cp/6 rpm, particularly 300-3,000 cp/6 rpm ~B
type viscometer) in the case of a water-soluble or 35 water-dispersible coat:ing, and apply;ng, by spray coat-ing or the like, the resulting material so as to form a -coating fiIm of, for example, about 10-70 ~m, particu-larly about 15-50 ~m in thickness as cured. In the present method, it is preferred as mentioned previously that the first color base coating (B) is applied, the resulting coating fiIm is air-dried at room temperature by air blowing or the like withou~ substantially curing the fiIm, and then the second color base coatil1g (C) is applied. After the appl ication of the second color base coating (C), heating is conducted at a temperature of 10 about 80-170~C, prefe~rably about 120-160~C for about 3-40 minutes, preferablly about 10-30 minutes, whereby the first color base coaling (B) and the second color base coating (C) can be cured simultaneously. For the heat-ing, there can be used a method ordinarily use~, such as hot-air heating, infrared heating, high-frequency heat-ing or the like.
Clear coatin~ (D) According 1:o the present invention, é~ clear coating ~D) can be applied on the film of the second 20 color base coating ((') so that the multi-layer coating fiIm formed is further improved in aesthetic e1fect, finish appearance, weat-herability, chemical resistance, water resistance, moisture resistance, etc. As the clear coating (D), there can be used a coating capable 25 of forming a colorless or color transparent fiIm.
Specifically, there c:an be used a per se known thermo-setting coating of walter-soluble or water-dispersible type, organic solvent: type or powder type, cont:aining a base material resin alnd a curing agent as the main 30 components and furthe~r containing, as necessary, a coloring pigment, a metallic pigment, a dye, et;c. in such amounts that the~ transparency of the coating fiIm formed is not substamt;ally impaired.
The base material resin and curing aeent usable in the water-soluble or water-dispersible coating and the organic solvent type coating, and the organic ~ CA 02219303 1997-10-24 solvent usable in the organic solvent type coa-ting can be selected from the specific examples mentione~d in the first color base coating (B). The proportions of the base material resin and the curing agent are preferably those also mentioned in the first color base coating.
The water-soluble or water-dispersible clear coating or the organic solvent type clear coating can be applied according to an ordinary method, by adding, to the coating, deionized water and/or an organic solvent 10 and, as necessary, aclditives such as thickener, anti-foaming agent and the like to adjust the sol;d content to about 10-9~% by wei ght, preferably about 30--80% by weight and the viscosity to 10-70 seconds, pre1~erably 15-40 seconds (Ford Cup #4/20~C) in the case ol: a sol-15 vent type coating ancl to 200-5,000 cp/6 rpm, preferably 300-3,000 cp/6 rpm (E~ type viscometer) in the case of a water-soluble or water-dispersible coating, and apply-ing, by spray coating: or the like, the resulting mate-rial so as to form a coating fiIm of, for exam~le, about 10-70 ~m, particularly about 15-50 ~m in thickness as cured. The coating fiIm formed can be cured by heating at a temperature of about 80-170~C, preferably about 120-t60~C for about 20-40 minutes. For the heating, there can be used a method ordinarily used, suc:h as hot-25 air heating, infrared heating, high-frequency heating or the like.
Meanwhile, the powder coating usable as the clear coating (D) is composed mainly of a base material resin and a curing agent as the main components. As the 30 base material resin, there can be mentioned, for exam-ple, an acrylic resin, a polyester resin, a fluoro-plastic, an urethane resin and their modifications (e.g.
a graft polymer) all having at least one crosslinkable functional group selected from hydroxyl group, carboxyl 3~ group, glycidyl group, etc. These resins are merely illustrations and the base material resin is not re-~ CA 02219303 1997-10-24 stricted thereto. The base material resin preferably has a glass transition temperature of generally 40~C or more, particularly 50-120~C, more particularly 6~-100~C.
There is no particular restriction as to the composi-tion, molecular weight, etc. of the base material resin,and they can be appropriately selected depending ~pon the purpose of the use of the coated article.
The curing agent is a component used to three-dimensionally crosslink and cure the base material resin 10 by heating. As the curing agent, there can be used. for example, an alkoxymethylolmelamine, a blocked polyiso-cyanate compound, an epoxy compound, an isocyanurate compound or an aliphatic dibasic acid.
The proportions of the base material resin and 15 the curing agent are most preferably such that the above-merttioned functional group of the base material resin and the functional group of the curing agent become about equimoliar.
The powder coating may further contain, as 20 necessary, additives for coating, such as fluidity-controlling agent, ultraviolet absorber, light stabi-lizer and the like.
The powder coating can be obtained ordinarily by meIt-kneading the above components, cooling the melt-kneaded material, and grinding it into appropriateparticle diameters.
The method by which the powder coatirtg is applied, is not partiicularly restricted, and there can be used an appropriai:e appliGation method for l)owder 30 coating, such as electrostatic spray coating, -Fluidized dip coating or the like.
The fiIm thickness at which the powder coating is applied, is not particularly restricted, ei1her;
however, the fiIm thickness is generally appropriate to 35 be 20-200 ~m. It is preferable to apply the powder coating at a fiIm thickness of particularly 20--120 ~m SQ
as to give a finished coating fiIm superior in smooth-ness, distinctness oIF image gloss, Juster, fattiness, etc. The curing tem~)erature of the fiIm of the powder coating can be taken at the curing temperature of the powder coating, for example, about 120-180~C, preferably about 130-170~C.
Exam~les The present invention is hereinafter described 10 more specificaIIy by way of ExampIes. In the follow-ings, ~parts" and "%" refer to "parts by weight" and a%
by weight~, respectiveIy.
I. Pre~aration of samoIes 1) Cationic eIectrocoatin~ (A) (A-1) "Electron ~g200"(product of Kansai Paint Co., Ltd., trade name, poIyamine-modified epoxy resin-blocked poIyisocyanate type) was diluted with deionizel~ water or the Iike so as to give a soIid content of about t6% by 20 weight. The resuIting material was eIectrodeposited by an ordinary method whiIe the pH was maintained at 5.5-8Ø The thickness of the coatin~ fiIm formed was about 20 ~m in terms of cured fiIm thickness. The coating fiIm was cured at about 175~C.
25 2) Second coIor base coatin~s (B) 50% acrYIic resin soIution (S-1) 30 parts ol: methyI methacryIate, 59 parts of ethyl acryIate, 10 parts of hydroxyethyI acryIate and 1 part of acrylic acid were polymerized by an ordinary 30 process, in the presence of a poIymerization initiator, a, a' -azobisisobutyronitriIe, in a mixed solvent of xyIene/n-butanol = 7()/30, whereby was obtained an acryl-ic resin soIution (S--1 ) having a weight-average moIecu-lar weight of 25,000 and a resin solid content of 50%.
20% aqueous acrvlic resin dis~ersion (W-1) In a reactor were placed 140 parts o-F de-ionized water, 2.5 parts of 30% UNewcol 707SFn (surfac-tant, product of Nipl)on Nyukazai Co., Ltd.) an~ 1 part of a monomer mixture (1) shown below. The reactor contents were stirred in a nitrogen gas current. There-to ~as added 3 parts of a 3% aqueous ammonium persulfate solution at 60~C. The resulting mixture was heated to 80~~. Into the reactor was fed, in 4 hours by the use 10 of a metering pump, a monomer emulsion consisting of 79 parts of the following monomer mixture (1), 2.5 parts of 30% UNewcol 707SF~, 4 parts of a 3% aqueous amlnonium persulfate solution and 42 parts of deionized ~Hater.
The resulting mixture was then subjected to aging for 1 hour. Into the reaclor were dropwise and simultaneously fed, at 80~C in 1.5 hours, 20.~ parts of a monomer mixture (2) shown bellow and 4 parts of a 3% aqueous ammonium persulfate solution. The resulting mixture was then subjected to agiing for 1 hour, then diluted with 30 20 parts of deionized water, and fiItered through a 200-mesh nylon cloth at 30~C. To the fiItrate was added deionized water, and the resulting mixture was adjusted to pH 7.5 using dimethylaminoethanol to obtain a 20%
aqueous acrylic resin dispersion (W-1) having an average 25 particle diameter of 0.1 ~m and a nonvolatile content of 20%.
Monomer mixture (1) Methyl methacrylate 55 part~;
Styrene 10 parts n-Butyl acrylate 9 part~;
2-Hydroxyel:hyl acrylate 5 parts Methacrylic: acid 1 part Monomer m;xture (2) Methyl methacrylate 5 part~, n-Butyl acrylate 7 part~;
2-Hydroxyet:hyl acrylate5 part~;
Methacrylic; acid 3 parts 30% "Newcol 707SF" 0.5 part 27% aqueousi melamine resin disPersion (M-1) Into a 2-liter four-necked flask equipped with a thermometer, a stirrer and a reflux condenser were placed 126 parts of melamine, 22~ parts of 80% parafor-maldehyde (product of Mitsui Toatsu Chemicals, Inc.) and ~92 parts of n-butanol. The mixture was adjusted to pH
9.~-10.0 using a 10% aqueous sodium hydroxide solution 10 and then subjected to a reaction at 80~C for 1 hour.
Thereto was added 88~1 parts of n-butanol. The resulting mixture was adjusted to pH ~.5-6.0 using a ~% ~;ulfuric acid solution and subjected to a reaction at 80~C for 3 hours. After the completion of the reaction, 1:he reac-15 tion mixture was neut:ralized with a 20% aqueous sodiumhydroxicJe solution to pH 7.0-7 5. Then, vacuum concen-tration was conducted at 60-70~C to remove n-butanol.
The residue was filtered to obtain a hydrophobic mela-mine resin. Nonvolatile content = 80%; dilution in 20 water-methanol mixed solvent (weight ratio: 3Ij/6~) =
2-Hydroxyet:hyl acrylate5 part~;
Methacrylic; acid 3 parts 30% "Newcol 707SF" 0.5 part 27% aqueousi melamine resin disPersion (M-1) Into a 2-liter four-necked flask equipped with a thermometer, a stirrer and a reflux condenser were placed 126 parts of melamine, 22~ parts of 80% parafor-maldehyde (product of Mitsui Toatsu Chemicals, Inc.) and ~92 parts of n-butanol. The mixture was adjusted to pH
9.~-10.0 using a 10% aqueous sodium hydroxide solution 10 and then subjected to a reaction at 80~C for 1 hour.
Thereto was added 88~1 parts of n-butanol. The resulting mixture was adjusted to pH ~.5-6.0 using a ~% ~;ulfuric acid solution and subjected to a reaction at 80~C for 3 hours. After the completion of the reaction, 1:he reac-15 tion mixture was neut:ralized with a 20% aqueous sodiumhydroxicJe solution to pH 7.0-7 5. Then, vacuum concen-tration was conducted at 60-70~C to remove n-butanol.
The residue was filtered to obtain a hydrophobic mela-mine resin. Nonvolatile content = 80%; dilution in 20 water-methanol mixed solvent (weight ratio: 3Ij/6~) =
3.6%; weight-average molecular weight = 800.
The melamine resin was placed in a vessel under stirring so that the solid content became 25 parts. Thereto was added 20 parts of an aqueous acrylic resin solution (a 50~, aqueous solution a resin made from n-butyl acrylate, met:hyl methacrylate, styrene, 2-hy-droxyethyl methacrylate and acrylic acid). While the resulting mixture was stirred using Disper of 1,000-1,500 rpm, 80 parts of deionized water was slo~vly added 30 thereto. Thereafter, stirring was conducted for 30 minutes to obtain an aqueous melamine resin dispersion (M-1) having a solid content of 27% and an average particle diameter of 0.11 ~m.
(B-1) ~0% acrylic: resin solution (S-1) 1~{) parts 88% Cymel 370 (Note 1) 2~ parts Pigment component-1 (Note 2) 30 parts Dibutyl acid phosphate 0.3 part The mixture of the above materials wa's sub-iected to viscosity adjustment with a mixed solvent con-sisting of 30 parts of toluene, 2CI parts of isol~utylalcohol, 30 parts of ~cellosolve acetate and 20 Darts of ~utyl cellosolve, so ;as to have a viscosity of 20 sec-onds (Ford Cup ~4/20~(,), whereby a first color base coating (B-1) of solv,ent type was obtained. The pigment 10 content of the coating (B-1) was 26.5 parts by weight per 100 parts by weight of the resin solid content (the base material resin and the curing agent~; the total content of the metallic pigment and/or the coloring pigment was 6.5 parts by weight per 100 parts by weight of the resin solid content (the base material resin and the curing agent); and the light transmittance of the coating fiIm formed was 0.1% or less when measured for a a cured fiIm of 30 ~m thickness.
(Note 1) 88% Gymel 370: trade name of Mitsui Cy-anamicl Ltd., contains 55% (as solid con-tent) of a mono-ring substance of meth-oxylat:ed methylol-melamine containing both methoxy group and methylol group.
(Note 2) Pigment component-2: a pigment component consisting of 10 parts of "Alumipaste N-1700Nl." (product of Toyo Aluminum K.K., trade name, aluminum content = 65%) and 20 par-ts of barium sulfate.
~B-2) 20% aqueous acrylic resin dispersion (W-1) 32~ parts 27% aqueous melamine resin dispersion (M-1) 131 parts Pigment component-2 (Note 3) 10 parts ~eionized water 171 parts "Acrysol ASE-60"(Note 4) 3 parts Dimethylaminoethanol 0.3 part The mixture of the above materials was sub-iected to viscosity adjustment with deionized uater so as to have a viscosity of 30 seconds (Ford Cup #4/20~C), to obtain a first color base coating (B-2) of aqueous type. The pigment content of the coating (B-2) was ~.5 parts by weight per 100 parts by weight of the resin solid content (the base material resin and the curing agent); the total content of the metallic pigment and/or 10 the coloring pigment was 6.5 parts by weight pe!r 100 parts by weight of the resin solid content (thel base material resin and the curing agent); and the light transmittance of the coating film formed was 0.1% or less when measured for a cured film of 30 ~m thickness.
(Note 3) Pigment component-2: "Alumipas~te N-1700NI" (trade name, product of Toyo Alu-minum K.K., aluminum content = ~5%).
(Note 4) Acrysol ASE-60: trade name, product of Rohm and Haas Co., thickener.
(B-3) 50% acrylic resin solution (S-1) 1~CI parts 88% Cymel 370 (Note 1) 2~, parts Pigment component-3 (Note ~) 21, parts ~ibutyl acid phosphate 0.3 part The mixture of the above materials wals sub-jected to viscosity a,djustment with a mixed solvent con-sisting of 30 parts a,f toluene, 20 parts of isobutyl alcohol, 30 parts of cellosolve acetate and 20 parts of butyl cellosolve, so as to have a viscosity of 20 sec-30 onds (Ford Cup #4/20~lC), whereby a first color base coating (B-3) of sol~ent type was obtained. The pigment content of the coating (B-3) was 23 parts by we:ight per 100 parts by weight a,f the resin solid content (the base materia~ resin and thle curing agent); the total content 3~ of the metallic pigment and/or the coloring Pi~iment was 3 parts by weight per ~00 parts by weight of the resin solid content (the base material resin and the curing agent); and the light transmittance of the coating film formed was 0.1% or less when measured for a cur~ed fiIm of 30 ~m thickness.
(Note 5) Pigment component-3: a pigment component consisting of 3 parts of carbon black and 20 parts of barium sulfate.
(E-1) (for com~arison) 50% acrylic resin solution (S-1) 150 parts 88% Cymel 370 (Note 1) 28 parts Pigment component-4 (Note 6) 28 parts Dibutyl aci~ phosphate 0.3 part The mixture of the above materials was sub-jected to viscosity a,djustment with a mixed solvent con-sisting of 30 parts of toluene, 20 parts of isobu~yl alcohol, 30 parts of cellosolve acetate and 20 parts of butyl cellosolve, so ;as to have a viscosity of 20 sec-onds (Ford Cup #4J20~(,), whereby a color base coating (E-1) of solvent type for comparison was obtained. The pigment ccontent of th,e coating (E-1) was 28 parts by weight per 100 parts Iby weight of the resin solid con-tent (the base materiial resin and the curing agent); the total content of the metallic pigment and/or the color-ing pigment was 8 parts by weight per 100 parts by 25 weight of the resin solid content (the base material resin and the curing ;agent); and the light transmittance of the coating fiIm formed was 0.1% or less when mea-sured for a cured fih~ of 30 ~m thickness.
(Note 6) Pigment component-4: a pigment component consisting of 3 parts of carbon black, 5 parts of S'lnfinite Color YBG-06-SK3"
(pearlescent pigment, product of Shiseido Co., Ltd., trade name) and 20 parts of barium sulfate.
3) Second color base coatin~s (C) (C--1 ) 50% acrylic resin solution (S-1) 150 ~arts 88% Cymel 370 (Note 1) 28 parts Pigment comlponent-5 (Note 7) 3 parts Dibutyl aci~d phosphate 0.3 part The mixture of the above materials was sub-jected to viscosity adjustment with a mixed solvent con-sisting of 30 parts of toluene, 20 parts of isobutyl 10 alcohol, 30 parts of cellosolve acetate and 20 parts of butyl cellosolve, so as to have a viscosity of 20 sec-onds (Ford Cup #4/20&,), whereby a second color base coating (C-1) of solvent type was obtained. The pigment content of the coating ~C-1) was 2.2 parts by weight per 100 parts by weight of the resin solid content (the base material resin and the curing agent); the total content of the metallic pigment and/or the coloring pigment was 2.2 parts by weight per 100 parts by weight of the resin solid content ~the base material resin and the curing 20 agent); and the l;ght transmittance of the coating fiIm formed was 10% when measured for a cured fiIm af 30 ~m thickness.
(Note 7) Pigment component-5: "Alumipaste 891K"
(trade name), product of Toyo Aluminum K.K., aluminum content = 72%.
(C-2) 20% aqueous acrylic resin dispersion (W-1) 32~i parts 27% aqueous melamine resin dispersion ~M-1) 131 parts Pi~ment component-5 (Note 7)3, parts Deionized water 171 parts "Acrysol ASE-60" (Note 4) 3, parts Dimethylaminoethanol Cl.3 part The mixture of the above materials wals sub-jected to viscosity adjustment with deionized ~later so as to have a viscosit;y of 30 seconds (Ford Cup #4/20~C), to obtain a second color base coating (C-2) of aqueous type. The pigment content of the coating tC-2) was 2.2 par-~s b~ weight per 100 parts by weight of the resin solid content (the balse material resin and the curing agent); the total content of the metallic pigme~nt and/or the coloring pigment was 2.2 parts by weight per 100 parts by weight of the resin solid content (the base material resin and the curing agent); and the liight 10 transmittance of the coating film formed was 7()% when measured for a cured fiIm of 30 ~m thickness.
(C-3) 50% acrylic: resin solution (S-1) 150 parts 88% Cymel 370 (Note 1) 2~ parts Pigment component-6 (Note 8) 11.5 parts Dibutyl acid phosphate ().3 part The mixture of the above materials WélS sub-jected to viscosity adjustment with a mixed solvent con-sisting of 30 parts of toluene, 20 parts of isobutyl 20 alcohol, 30 parts of cellosolve acetate and 20 parts of butyl cellosolve, so as to have a viscosity of 2a sec-onds (Ford Cup #4/20'~C) ~ whereby a second colol base coating (C-3) of sol~ent type was obtained. The pigment content of the coating (C-3) was 1.5 parts by ~eight per 100 part:s by weight of the resin solid content (the base material resin and the curing agent); the total content of the metallic pigment and/or the coloring pigment was 1.5 parts by weight per 100 parts by weight of the resin solid content (the base material resin and the curing 30 agent); and the light transmittance of the coa-ting film formed was 10% when measured for a cured fiIm of 30 ~m thickness.
(Note 8) Pigment component-~: "Infinite Color YGB-06-SK3" (pearlescent pigment, product of Shiseido Co., Ltd., trade name).
. CA 02219303 1997-10-24 ~ .
The melamine resin was placed in a vessel under stirring so that the solid content became 25 parts. Thereto was added 20 parts of an aqueous acrylic resin solution (a 50~, aqueous solution a resin made from n-butyl acrylate, met:hyl methacrylate, styrene, 2-hy-droxyethyl methacrylate and acrylic acid). While the resulting mixture was stirred using Disper of 1,000-1,500 rpm, 80 parts of deionized water was slo~vly added 30 thereto. Thereafter, stirring was conducted for 30 minutes to obtain an aqueous melamine resin dispersion (M-1) having a solid content of 27% and an average particle diameter of 0.11 ~m.
(B-1) ~0% acrylic: resin solution (S-1) 1~{) parts 88% Cymel 370 (Note 1) 2~ parts Pigment component-1 (Note 2) 30 parts Dibutyl acid phosphate 0.3 part The mixture of the above materials wa's sub-iected to viscosity adjustment with a mixed solvent con-sisting of 30 parts of toluene, 2CI parts of isol~utylalcohol, 30 parts of ~cellosolve acetate and 20 Darts of ~utyl cellosolve, so ;as to have a viscosity of 20 sec-onds (Ford Cup ~4/20~(,), whereby a first color base coating (B-1) of solv,ent type was obtained. The pigment 10 content of the coating (B-1) was 26.5 parts by weight per 100 parts by weight of the resin solid content (the base material resin and the curing agent~; the total content of the metallic pigment and/or the coloring pigment was 6.5 parts by weight per 100 parts by weight of the resin solid content (the base material resin and the curing agent); and the light transmittance of the coating fiIm formed was 0.1% or less when measured for a a cured fiIm of 30 ~m thickness.
(Note 1) 88% Gymel 370: trade name of Mitsui Cy-anamicl Ltd., contains 55% (as solid con-tent) of a mono-ring substance of meth-oxylat:ed methylol-melamine containing both methoxy group and methylol group.
(Note 2) Pigment component-2: a pigment component consisting of 10 parts of "Alumipaste N-1700Nl." (product of Toyo Aluminum K.K., trade name, aluminum content = 65%) and 20 par-ts of barium sulfate.
~B-2) 20% aqueous acrylic resin dispersion (W-1) 32~ parts 27% aqueous melamine resin dispersion (M-1) 131 parts Pigment component-2 (Note 3) 10 parts ~eionized water 171 parts "Acrysol ASE-60"(Note 4) 3 parts Dimethylaminoethanol 0.3 part The mixture of the above materials was sub-iected to viscosity adjustment with deionized uater so as to have a viscosity of 30 seconds (Ford Cup #4/20~C), to obtain a first color base coating (B-2) of aqueous type. The pigment content of the coating (B-2) was ~.5 parts by weight per 100 parts by weight of the resin solid content (the base material resin and the curing agent); the total content of the metallic pigment and/or 10 the coloring pigment was 6.5 parts by weight pe!r 100 parts by weight of the resin solid content (thel base material resin and the curing agent); and the light transmittance of the coating film formed was 0.1% or less when measured for a cured film of 30 ~m thickness.
(Note 3) Pigment component-2: "Alumipas~te N-1700NI" (trade name, product of Toyo Alu-minum K.K., aluminum content = ~5%).
(Note 4) Acrysol ASE-60: trade name, product of Rohm and Haas Co., thickener.
(B-3) 50% acrylic resin solution (S-1) 1~CI parts 88% Cymel 370 (Note 1) 2~, parts Pigment component-3 (Note ~) 21, parts ~ibutyl acid phosphate 0.3 part The mixture of the above materials wals sub-jected to viscosity a,djustment with a mixed solvent con-sisting of 30 parts a,f toluene, 20 parts of isobutyl alcohol, 30 parts of cellosolve acetate and 20 parts of butyl cellosolve, so as to have a viscosity of 20 sec-30 onds (Ford Cup #4/20~lC), whereby a first color base coating (B-3) of sol~ent type was obtained. The pigment content of the coating (B-3) was 23 parts by we:ight per 100 parts by weight a,f the resin solid content (the base materia~ resin and thle curing agent); the total content 3~ of the metallic pigment and/or the coloring Pi~iment was 3 parts by weight per ~00 parts by weight of the resin solid content (the base material resin and the curing agent); and the light transmittance of the coating film formed was 0.1% or less when measured for a cur~ed fiIm of 30 ~m thickness.
(Note 5) Pigment component-3: a pigment component consisting of 3 parts of carbon black and 20 parts of barium sulfate.
(E-1) (for com~arison) 50% acrylic resin solution (S-1) 150 parts 88% Cymel 370 (Note 1) 28 parts Pigment component-4 (Note 6) 28 parts Dibutyl aci~ phosphate 0.3 part The mixture of the above materials was sub-jected to viscosity a,djustment with a mixed solvent con-sisting of 30 parts of toluene, 20 parts of isobu~yl alcohol, 30 parts of cellosolve acetate and 20 parts of butyl cellosolve, so ;as to have a viscosity of 20 sec-onds (Ford Cup #4J20~(,), whereby a color base coating (E-1) of solvent type for comparison was obtained. The pigment ccontent of th,e coating (E-1) was 28 parts by weight per 100 parts Iby weight of the resin solid con-tent (the base materiial resin and the curing agent); the total content of the metallic pigment and/or the color-ing pigment was 8 parts by weight per 100 parts by 25 weight of the resin solid content (the base material resin and the curing ;agent); and the light transmittance of the coating fiIm formed was 0.1% or less when mea-sured for a cured fih~ of 30 ~m thickness.
(Note 6) Pigment component-4: a pigment component consisting of 3 parts of carbon black, 5 parts of S'lnfinite Color YBG-06-SK3"
(pearlescent pigment, product of Shiseido Co., Ltd., trade name) and 20 parts of barium sulfate.
3) Second color base coatin~s (C) (C--1 ) 50% acrylic resin solution (S-1) 150 ~arts 88% Cymel 370 (Note 1) 28 parts Pigment comlponent-5 (Note 7) 3 parts Dibutyl aci~d phosphate 0.3 part The mixture of the above materials was sub-jected to viscosity adjustment with a mixed solvent con-sisting of 30 parts of toluene, 20 parts of isobutyl 10 alcohol, 30 parts of cellosolve acetate and 20 parts of butyl cellosolve, so as to have a viscosity of 20 sec-onds (Ford Cup #4/20&,), whereby a second color base coating (C-1) of solvent type was obtained. The pigment content of the coating ~C-1) was 2.2 parts by weight per 100 parts by weight of the resin solid content (the base material resin and the curing agent); the total content of the metallic pigment and/or the coloring pigment was 2.2 parts by weight per 100 parts by weight of the resin solid content ~the base material resin and the curing 20 agent); and the l;ght transmittance of the coating fiIm formed was 10% when measured for a cured fiIm af 30 ~m thickness.
(Note 7) Pigment component-5: "Alumipaste 891K"
(trade name), product of Toyo Aluminum K.K., aluminum content = 72%.
(C-2) 20% aqueous acrylic resin dispersion (W-1) 32~i parts 27% aqueous melamine resin dispersion ~M-1) 131 parts Pi~ment component-5 (Note 7)3, parts Deionized water 171 parts "Acrysol ASE-60" (Note 4) 3, parts Dimethylaminoethanol Cl.3 part The mixture of the above materials wals sub-jected to viscosity adjustment with deionized ~later so as to have a viscosit;y of 30 seconds (Ford Cup #4/20~C), to obtain a second color base coating (C-2) of aqueous type. The pigment content of the coating tC-2) was 2.2 par-~s b~ weight per 100 parts by weight of the resin solid content (the balse material resin and the curing agent); the total content of the metallic pigme~nt and/or the coloring pigment was 2.2 parts by weight per 100 parts by weight of the resin solid content (the base material resin and the curing agent); and the liight 10 transmittance of the coating film formed was 7()% when measured for a cured fiIm of 30 ~m thickness.
(C-3) 50% acrylic: resin solution (S-1) 150 parts 88% Cymel 370 (Note 1) 2~ parts Pigment component-6 (Note 8) 11.5 parts Dibutyl acid phosphate ().3 part The mixture of the above materials WélS sub-jected to viscosity adjustment with a mixed solvent con-sisting of 30 parts of toluene, 20 parts of isobutyl 20 alcohol, 30 parts of cellosolve acetate and 20 parts of butyl cellosolve, so as to have a viscosity of 2a sec-onds (Ford Cup #4/20'~C) ~ whereby a second colol base coating (C-3) of sol~ent type was obtained. The pigment content of the coating (C-3) was 1.5 parts by ~eight per 100 part:s by weight of the resin solid content (the base material resin and the curing agent); the total content of the metallic pigment and/or the coloring pigment was 1.5 parts by weight per 100 parts by weight of the resin solid content (the base material resin and the curing 30 agent); and the light transmittance of the coa-ting film formed was 10% when measured for a cured fiIm of 30 ~m thickness.
(Note 8) Pigment component-~: "Infinite Color YGB-06-SK3" (pearlescent pigment, product of Shiseido Co., Ltd., trade name).
. CA 02219303 1997-10-24 ~ .
4) Clear coatin~s (D~
(D-1) 25 parts of methyl methacrylate, 25 parts of ethyl acrylate, 36.~ parts of n-butyl acrylate, 12 parts of 2-hydroxyethyl acrylate. 1.5 parts of acrylic acid and 2.5 parts of a polymerization initiator (~,~'-azo-bisisobutyronitrile) were polymerized in xylene to obtain an acrylic resin solution having a resin solid content of 60%. The resin had a hydroxyl value of 58 10 and an acid value of 12. The resin was mixed nith "U-Van 20SE" (hydrophobic melamine resin, product of Mitsui Toatsu Chemicals. Inc., nonvolatile content = ~10%, weight-average molecular weight = 3,000-4,000) in a solid content weight ratio of 75:25~ The resulting 15 mixture was subjected to viscosity adjustment vuith an organic solvent to a viscosity of 25 seconds (Ford Cup #4/20~C), to obtain a clear coating (D-1) of solvent type.
(D-2) 20% aqueous acrylic resin dispersion (W-1) 32~i parts 27% aqueous melamine resin dispersiorl (M-1) 131 parts Deionized vuater 171 parts "Acrysol AS,E-60" (Note 4) 3 parts Dimethylaminoethanol ~1.3 part The mixture~ of the above materials was sub-jected to viscosity adjustment with deionized vJater so as to have a viscosit:y of 30 seconds (Ford Cup #4~20~C), 30 to obtain a clear coating (D-2) of aqueous type.
(D-3) Into a flask were fed 40 parts of mel:hyl methacrylate, 30 part:s of n-butyl methacrylate, 30 parts of glycidyl methacrylate, 10 parts of styrene, 1 part of 35 tert-butyl peroxide i'polymerization initiator) and 2 parts of potassium oleate soap (surfactant). They were heat-polymerized by suspension polymerization. The resulting copolymer (glass transition temperature =
about 60~C) was dried. 100 parts of the copolymer was melt-kneaded with 25 parts of decamethylenedicarboxylic acid and 1 part of a film surface conditioner bly the use of a heated kneader at 120~C for 10 minutes. Ihe kneaded material was cooled and then ground by the use of a grinder to obtain a clear coating (D-3) o~: powder type having particle diameters of about 20-150 ~m.
Il. Examoles and Comoarative Examoles Examples 1-5 A steel plate, which had been subiected to a surface treatment with "Bonderite #3030~' (product of Nihon Parkerizing Company Limited, zinc phosphate treat-15 ment agent), was immersed in a bath of the cationicelectrocoating (A-1), and electrodeposition was con-ducted according to an ordinary method. The thickness of the coating fiIm formed was about 20 ~m as cured.
The electrocoated steel plate was pulled up from the 20 bath, water-washed, alnd heated to about 175~C 1:o cure the electrocoating fiIm. Then, on the cured electro-coating film was applied, by air spraying, the first color base coating (E,-1) or (B-3) of solvent type having a viscosity (Ford Cu~ #4/20~C) of 20 seconds or the 25 first color base coat:ing (B-2) of aqueous type having a viscosity (Ford Cup ~4/20~C) of 30 seconds so as to give a coating fiIm of about 20 ~m thickness as cured. The resulting material W21S allowed to stand at room tempera-ture for about 10 minutes.
Then, on the uncured fiIm of the first color base coating was applied, by air spraying, the second color base coating (C-1) or (C-3) of solvent t!~pe having a viscosity (Ford CUFI #4/20~C) of 20 seconds or the second color base coclting (C-2) of aqueous type having a viscosity (Ford Cup ~4/20~C) of 30 seconds so as to give a coating film of about 30 ~m thickness as cured. The resulting material was allowed to stand at room tempera-ture for about 10 minutes and then heated at 140~C for 30 minutes to crosslink and cure the films of the first color base coating and the second color base cc,ating simultaneously.
Then, on the cured fiIm of the second color base coating was applied, by air spraying, the clear coating (D-1) of sol~ent type having a viscosity (Ford Cup #4/2Q~C) of 25 seconds or the clear coating (D-2) of 10 aqueous type having al viscosity ~Ford Cup #4/2C1~C) of 25 seconds so as to give a coating fiIm of about 4-0 ~m thickness as cured, or was applied, by electrostatic powder coating, the clear coating (D-3) of powcler type so as to give a coating fiIm of 50 ~m thickness as cured. The resultinF; material was allowed to s;tand at room temperature for about 10 minutes and then heated under the baking conclitions shown in Table 1 appearing later, to give rise t:o crosslinking and curing.
Gomparative ExamDle 1 On the cured electrocoating film obtained above was applied, by air spraying, a solvent t:ype intermediate coating "TP-37" (product of Kansai Paint Co., Ltd., trade name~) having a viscosity (For Cup #4/20~C) of 20 seconcls so as to give a fiIm of about 30 2~ ~m thickness as cureal. The resulting material was allowed to stand at room temperature for about 10 min-utes and then heated at 140~C for 30 minutes.
Then, on thle cured fiIm of the intermediate coating was applied, by air spray;ng, the first; color base coating (B-1) of solvent type having a viscosity (For Cup #4/20~C) of 20 seconds so as to give a fiIm of about 1~ ~m thickness; as cured. The resulting material was allowed to stand at room temperature for about 10 minutes.
Then, on the uncured fiIm of the fir~it color base coating was applied, by air spraying, the clear -coating (D-1) of solvent type having a viscosit.y (For Gup #4/20~C) of 25 seconds so as to give a film of about 40 ~m thickness as cu,red. The resulting material was allowed to stand at room temperature for about 1C min-utes and then heated at 140~C for 30 minutes to cross-link and cure the fiIms of the first color base coating and the second color base coating simultaneously.
ComParative Exam~le 2 On the cured electrocoating fiIm obt~lined 10 above was applied, by air spraying, the ~irst c:olor base coating ~C-1) of solvent type having a viscosit:y (For Cup #4/20~C) of 20 seconds so as to give a film of about 18 ~m thickness as cured. The resuiting material was allowed to stand at room temperature for about 10 min-utes. Then, on the uncured fiIm of the second colorbase coating (C-1) wals applied, by air sprayin~jr, the clear coating (D-1) c~f solvent type having a viscosity (For Cup #4/20~C) of 25 seconds so as to give a fiIm of about 40 ~m thickness; as cured. The resulting material 20 was allowed to stand at room temperature for about 10 minutes and then heat:ed at 140~C for 30 minutes to give rise to crosslinking and curing.
Comparative ExamPle 3 An operation was conducted in the sanle manner 25 as in Example 1 except that (C-1) was used as 1:he first color base coating arld (B-1) was used as the second color base coating.
Com~arative Examole 4~
An operation was conducted in the same manner 30 as in Comparative Example 1 except that (E-1) was used as the first color base coating.
Ill. Performance test results The multi-layer coating films obtained in the above Examples and Comparative Examples were subjected 35 to performance tests. The results thereof are shown in Table 1.
Test methods Flat-area Finis~
Measured b!) the use of a tester for ~istinct-ness of image gloss, Model PGD-IV (marketer: J,~PAN
COLOUR RESEARCH INSTITUTE~. A larger value indicates higher distinctness of image gloss.
Outdoor durabilitv A coated plate was subjected to accelerated exposure for 200 hours in a sunshine weatherometer (light amount: 1,101~ KJoule/mZ.hr) and then immersed in hot water of 40~C for 24 hours. This procedure was taken as 1 cycle and repeated 25 times (25 cycles).
Then, at the surface of the resulting plate were formed 100 squares each of .2 mm x 2 mm according to ~IS K 5400 15 8.5.2 (cross-cut test method); a tape was sticked there-on and peeled; the e:xtent of peeling appearing in squares was examined according to the following stan-dard.
O : There is no intercoat adhesion failure.
X : There is partial or complete peeling be-tween the electrocoating fiIm and the base coating fiIm.
ChiP~in~ resistance Using a gravelometer (product of a Panel Co.), 25 500 g of No. 7 crushed stones were sprayed onto a coat-ing film at an angle of 45~ at an air pressure of 0.3 MPa at -20~C to apply an impact to the coating film.
Then, a pressure-sensitive tape was sticked onto the coating film and quickly peeled, after which ti~e extent 30 of fiIm peeling in the vicinity of the scars generated by the ;mpact was examined.
O : There is no or substantially no film peeling in the vicinity of scars.
A : There is distinct film peeling in the vicinity of scars.
X : There is striking film peeling in the ..
vicinity of scars.
Brilliance feelin~
A coated plate was visually examined according to the following standard.
~: Very good brilliance feeling.
O : Good brilliance feeling.
X: Poor brilliance feeling.
Intensitv of interference color A C* value at an incident angle of 45~ and a receiving angle of 115~ was measured using MA68 of X-Rite Co. A larger value indicates a higher aesthetic effect.
FliP-flo~ l~roPerty Alignment of aluminum was examined by the use of "Alcope" (name of metallic feeling tester produced by 15 Kansai Paint Co.. Ltd.). A larger value indicates superior aluminum alignment ..
..
_ 30 3 c~ o o ~m @) ~7 ~ ~3) ~t O O <I O
r ~ I l l l l l cl Q ~ ~ ~ ~ O X X ~ I _ F Z F
3 ~ I ~ ~ I ~ - o O ~ ~ I -- X
~ I I I I ~ ~ I (~ o O ~) I co ~OD
-- ~ ~ I I I I ~ I @) O I (~ 1 Vll o o ~
CO
~!C ~3 '~~ ~ ~ ~ I ~ ~ I~ C,~ I ~ ~ Vll o o ~ o O I ~ C~~ I~ e~~ ~ O O ~ I _~l~
-- -- ~ ~ I I I I '' ~ 0 ~ Vll o o ~ ll_ @) 2:~
a~
C~ o o ---2, ~ 2 E
bOI bO 0 .bO C'~J
---Ci --- O --- O X
â) ~ o --- ~ o ---a~ o--- q~ - O~
o o ~ ~ ~ ~ ~ ~ r~
o, O~o o ~ ~o O ~
bO 0 bO 0 . --bO ~-- bO ~ -- bO ~ ~
Q -- E Q --- E Q E
~~'--~, ~._ ~, ~ -- o ci~
8 ~ ~ 8 ~ ~ ~n m i~ cn m ~ c~ ~ m L~ ~D O
o o ~ o o I I a~ ~
o o --- o o --- O ~ ~D ~ _ -- bO ~ -- ~O ~ ~ C ~ O O bO :~ O bO ~
Q --- F Q _ E0 Q .IJ O O ~D ~ ~ 0 ~ (D O
r ~ -- E Y -- ~ o-- ~ bO ~ D --- ~
cn m L~ c~ mn5 ~ O ~o~ m c~ 8 ~~ ' o 88 -~ Q ~D O ~ ~-O ~ o o t~ ~ ~ O ~. Q c~
D bO ~ ~ O ~n ~S ~ bO ~ ~ C) bO ~ O --- -- 0 ~ _~
O ~ ~ O ~ ~ ~ o Q o Q-- ~ I ~D
S --- --- O ~ ~ Q -- ~D ~ .~--- a~ --._.--~ -- ~ ~ ~ --- -- ~ --- o QQ~ o~ Q~ ~ o Q ~ L~ O o m ~ ~ Z
cc O o cc O E O ~ o sd~s ~lu ! ~eo~ ucl ! ~n I ~A3 Industrial Applicability The present method is a coating method which is applied at a low ,_ost, which gives a coating fiim very superior in finish appearance, aesthetic leffect, corrosion resistance, weatherability, chipping resist-ance, etc. and which is advantageous in resource saving and pollution control; and can be extensively ~tilized in coating of automobiles, bicycles, electric appli-ances, etc.
(D-1) 25 parts of methyl methacrylate, 25 parts of ethyl acrylate, 36.~ parts of n-butyl acrylate, 12 parts of 2-hydroxyethyl acrylate. 1.5 parts of acrylic acid and 2.5 parts of a polymerization initiator (~,~'-azo-bisisobutyronitrile) were polymerized in xylene to obtain an acrylic resin solution having a resin solid content of 60%. The resin had a hydroxyl value of 58 10 and an acid value of 12. The resin was mixed nith "U-Van 20SE" (hydrophobic melamine resin, product of Mitsui Toatsu Chemicals. Inc., nonvolatile content = ~10%, weight-average molecular weight = 3,000-4,000) in a solid content weight ratio of 75:25~ The resulting 15 mixture was subjected to viscosity adjustment vuith an organic solvent to a viscosity of 25 seconds (Ford Cup #4/20~C), to obtain a clear coating (D-1) of solvent type.
(D-2) 20% aqueous acrylic resin dispersion (W-1) 32~i parts 27% aqueous melamine resin dispersiorl (M-1) 131 parts Deionized vuater 171 parts "Acrysol AS,E-60" (Note 4) 3 parts Dimethylaminoethanol ~1.3 part The mixture~ of the above materials was sub-jected to viscosity adjustment with deionized vJater so as to have a viscosit:y of 30 seconds (Ford Cup #4~20~C), 30 to obtain a clear coating (D-2) of aqueous type.
(D-3) Into a flask were fed 40 parts of mel:hyl methacrylate, 30 part:s of n-butyl methacrylate, 30 parts of glycidyl methacrylate, 10 parts of styrene, 1 part of 35 tert-butyl peroxide i'polymerization initiator) and 2 parts of potassium oleate soap (surfactant). They were heat-polymerized by suspension polymerization. The resulting copolymer (glass transition temperature =
about 60~C) was dried. 100 parts of the copolymer was melt-kneaded with 25 parts of decamethylenedicarboxylic acid and 1 part of a film surface conditioner bly the use of a heated kneader at 120~C for 10 minutes. Ihe kneaded material was cooled and then ground by the use of a grinder to obtain a clear coating (D-3) o~: powder type having particle diameters of about 20-150 ~m.
Il. Examoles and Comoarative Examoles Examples 1-5 A steel plate, which had been subiected to a surface treatment with "Bonderite #3030~' (product of Nihon Parkerizing Company Limited, zinc phosphate treat-15 ment agent), was immersed in a bath of the cationicelectrocoating (A-1), and electrodeposition was con-ducted according to an ordinary method. The thickness of the coating fiIm formed was about 20 ~m as cured.
The electrocoated steel plate was pulled up from the 20 bath, water-washed, alnd heated to about 175~C 1:o cure the electrocoating fiIm. Then, on the cured electro-coating film was applied, by air spraying, the first color base coating (E,-1) or (B-3) of solvent type having a viscosity (Ford Cu~ #4/20~C) of 20 seconds or the 25 first color base coat:ing (B-2) of aqueous type having a viscosity (Ford Cup ~4/20~C) of 30 seconds so as to give a coating fiIm of about 20 ~m thickness as cured. The resulting material W21S allowed to stand at room tempera-ture for about 10 minutes.
Then, on the uncured fiIm of the first color base coating was applied, by air spraying, the second color base coating (C-1) or (C-3) of solvent t!~pe having a viscosity (Ford CUFI #4/20~C) of 20 seconds or the second color base coclting (C-2) of aqueous type having a viscosity (Ford Cup ~4/20~C) of 30 seconds so as to give a coating film of about 30 ~m thickness as cured. The resulting material was allowed to stand at room tempera-ture for about 10 minutes and then heated at 140~C for 30 minutes to crosslink and cure the films of the first color base coating and the second color base cc,ating simultaneously.
Then, on the cured fiIm of the second color base coating was applied, by air spraying, the clear coating (D-1) of sol~ent type having a viscosity (Ford Cup #4/2Q~C) of 25 seconds or the clear coating (D-2) of 10 aqueous type having al viscosity ~Ford Cup #4/2C1~C) of 25 seconds so as to give a coating fiIm of about 4-0 ~m thickness as cured, or was applied, by electrostatic powder coating, the clear coating (D-3) of powcler type so as to give a coating fiIm of 50 ~m thickness as cured. The resultinF; material was allowed to s;tand at room temperature for about 10 minutes and then heated under the baking conclitions shown in Table 1 appearing later, to give rise t:o crosslinking and curing.
Gomparative ExamDle 1 On the cured electrocoating film obtained above was applied, by air spraying, a solvent t:ype intermediate coating "TP-37" (product of Kansai Paint Co., Ltd., trade name~) having a viscosity (For Cup #4/20~C) of 20 seconcls so as to give a fiIm of about 30 2~ ~m thickness as cureal. The resulting material was allowed to stand at room temperature for about 10 min-utes and then heated at 140~C for 30 minutes.
Then, on thle cured fiIm of the intermediate coating was applied, by air spray;ng, the first; color base coating (B-1) of solvent type having a viscosity (For Cup #4/20~C) of 20 seconds so as to give a fiIm of about 1~ ~m thickness; as cured. The resulting material was allowed to stand at room temperature for about 10 minutes.
Then, on the uncured fiIm of the fir~it color base coating was applied, by air spraying, the clear -coating (D-1) of solvent type having a viscosit.y (For Gup #4/20~C) of 25 seconds so as to give a film of about 40 ~m thickness as cu,red. The resulting material was allowed to stand at room temperature for about 1C min-utes and then heated at 140~C for 30 minutes to cross-link and cure the fiIms of the first color base coating and the second color base coating simultaneously.
ComParative Exam~le 2 On the cured electrocoating fiIm obt~lined 10 above was applied, by air spraying, the ~irst c:olor base coating ~C-1) of solvent type having a viscosit:y (For Cup #4/20~C) of 20 seconds so as to give a film of about 18 ~m thickness as cured. The resuiting material was allowed to stand at room temperature for about 10 min-utes. Then, on the uncured fiIm of the second colorbase coating (C-1) wals applied, by air sprayin~jr, the clear coating (D-1) c~f solvent type having a viscosity (For Cup #4/20~C) of 25 seconds so as to give a fiIm of about 40 ~m thickness; as cured. The resulting material 20 was allowed to stand at room temperature for about 10 minutes and then heat:ed at 140~C for 30 minutes to give rise to crosslinking and curing.
Comparative ExamPle 3 An operation was conducted in the sanle manner 25 as in Example 1 except that (C-1) was used as 1:he first color base coating arld (B-1) was used as the second color base coating.
Com~arative Examole 4~
An operation was conducted in the same manner 30 as in Comparative Example 1 except that (E-1) was used as the first color base coating.
Ill. Performance test results The multi-layer coating films obtained in the above Examples and Comparative Examples were subjected 35 to performance tests. The results thereof are shown in Table 1.
Test methods Flat-area Finis~
Measured b!) the use of a tester for ~istinct-ness of image gloss, Model PGD-IV (marketer: J,~PAN
COLOUR RESEARCH INSTITUTE~. A larger value indicates higher distinctness of image gloss.
Outdoor durabilitv A coated plate was subjected to accelerated exposure for 200 hours in a sunshine weatherometer (light amount: 1,101~ KJoule/mZ.hr) and then immersed in hot water of 40~C for 24 hours. This procedure was taken as 1 cycle and repeated 25 times (25 cycles).
Then, at the surface of the resulting plate were formed 100 squares each of .2 mm x 2 mm according to ~IS K 5400 15 8.5.2 (cross-cut test method); a tape was sticked there-on and peeled; the e:xtent of peeling appearing in squares was examined according to the following stan-dard.
O : There is no intercoat adhesion failure.
X : There is partial or complete peeling be-tween the electrocoating fiIm and the base coating fiIm.
ChiP~in~ resistance Using a gravelometer (product of a Panel Co.), 25 500 g of No. 7 crushed stones were sprayed onto a coat-ing film at an angle of 45~ at an air pressure of 0.3 MPa at -20~C to apply an impact to the coating film.
Then, a pressure-sensitive tape was sticked onto the coating film and quickly peeled, after which ti~e extent 30 of fiIm peeling in the vicinity of the scars generated by the ;mpact was examined.
O : There is no or substantially no film peeling in the vicinity of scars.
A : There is distinct film peeling in the vicinity of scars.
X : There is striking film peeling in the ..
vicinity of scars.
Brilliance feelin~
A coated plate was visually examined according to the following standard.
~: Very good brilliance feeling.
O : Good brilliance feeling.
X: Poor brilliance feeling.
Intensitv of interference color A C* value at an incident angle of 45~ and a receiving angle of 115~ was measured using MA68 of X-Rite Co. A larger value indicates a higher aesthetic effect.
FliP-flo~ l~roPerty Alignment of aluminum was examined by the use of "Alcope" (name of metallic feeling tester produced by 15 Kansai Paint Co.. Ltd.). A larger value indicates superior aluminum alignment ..
..
_ 30 3 c~ o o ~m @) ~7 ~ ~3) ~t O O <I O
r ~ I l l l l l cl Q ~ ~ ~ ~ O X X ~ I _ F Z F
3 ~ I ~ ~ I ~ - o O ~ ~ I -- X
~ I I I I ~ ~ I (~ o O ~) I co ~OD
-- ~ ~ I I I I ~ I @) O I (~ 1 Vll o o ~
CO
~!C ~3 '~~ ~ ~ ~ I ~ ~ I~ C,~ I ~ ~ Vll o o ~ o O I ~ C~~ I~ e~~ ~ O O ~ I _~l~
-- -- ~ ~ I I I I '' ~ 0 ~ Vll o o ~ ll_ @) 2:~
a~
C~ o o ---2, ~ 2 E
bOI bO 0 .bO C'~J
---Ci --- O --- O X
â) ~ o --- ~ o ---a~ o--- q~ - O~
o o ~ ~ ~ ~ ~ ~ r~
o, O~o o ~ ~o O ~
bO 0 bO 0 . --bO ~-- bO ~ -- bO ~ ~
Q -- E Q --- E Q E
~~'--~, ~._ ~, ~ -- o ci~
8 ~ ~ 8 ~ ~ ~n m i~ cn m ~ c~ ~ m L~ ~D O
o o ~ o o I I a~ ~
o o --- o o --- O ~ ~D ~ _ -- bO ~ -- ~O ~ ~ C ~ O O bO :~ O bO ~
Q --- F Q _ E0 Q .IJ O O ~D ~ ~ 0 ~ (D O
r ~ -- E Y -- ~ o-- ~ bO ~ D --- ~
cn m L~ c~ mn5 ~ O ~o~ m c~ 8 ~~ ' o 88 -~ Q ~D O ~ ~-O ~ o o t~ ~ ~ O ~. Q c~
D bO ~ ~ O ~n ~S ~ bO ~ ~ C) bO ~ O --- -- 0 ~ _~
O ~ ~ O ~ ~ ~ o Q o Q-- ~ I ~D
S --- --- O ~ ~ Q -- ~D ~ .~--- a~ --._.--~ -- ~ ~ ~ --- -- ~ --- o QQ~ o~ Q~ ~ o Q ~ L~ O o m ~ ~ Z
cc O o cc O E O ~ o sd~s ~lu ! ~eo~ ucl ! ~n I ~A3 Industrial Applicability The present method is a coating method which is applied at a low ,_ost, which gives a coating fiim very superior in finish appearance, aesthetic leffect, corrosion resistance, weatherability, chipping resist-ance, etc. and which is advantageous in resource saving and pollution control; and can be extensively ~tilized in coating of automobiles, bicycles, electric appli-ances, etc.
Claims (14)
1. A method for forming a multi-layer coating film, which is characterized by applying a cationic electrocoating on a metal-made material to be coated, heat-curing the resulting electrocoating film, applying, on the heat-cured electrocoating film, a first color base coating having a sublayer-hiding powder, applying, on the resulting coating film without substantially curing the film, a second color base coating having transparency, heating the two films of the first color base coating and the second color base coating to cure them, then applying is clear coating, and heat-curing the resulting clear coating film.
2. A method according to Claim 1, wherein the first color base coating contains a metallic pigment and/or a coloring pigment.
3. A method according to Claim 1, wherein the first color base coating has a light transmittance of 5%
or less when made into a cured film of 30 µm thickness.
or less when made into a cured film of 30 µm thickness.
4. A method according to Claim 1, wherein the first color base coating has a light transmittance of 3%
or less when made into a cured film of 30 µm thickness.
or less when made into a cured film of 30 µm thickness.
5. A method according to Claim 1, wherein the first color base coating contains pigment(s) in an amount of 1-250 parts by weight per 100 parts by weight of the resin solid content.
6. A method according to Claim 1, wherein the first color base coating is applied so as to give a cured film of 5-60 µm thickness.
7. A method according to Claim 1, wherein the second color base coating contains a metallic pigment and/or a coloring pigment.
8. A method according to Claim 1, wherein the second color base coating has a light transmittance of 6-95% when made into a cured film of 30 µm thickness.
9. A method according to Claim 1, wherein the second color base coating has a light transmittance of 10-90% when made into a cured film of 30 µm thickness.
10. A method according to Claim 1, wherein the second color base coating contains pigment(s) in an amount of 0.01-100 parts by weight per 100 parts by weight of the resin solid content.
11. A method according to Claim 1, wherein the second color base coating is applied so as to give a cured film of 10-70 µm thickness.
12. A method according to Claim 1, wherein the two films of the first color base coating and the second color base coating are heated at a temperature of 80-170°C to cure them.
13. A method according to Claim 1, wherein the clear coating is a water-soluble coating, a water-dispersible coating, an organic solvent type coating or a powder coating.
14. A coated article obtained by a method set forth in Claim 1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP127333/1995 | 1995-04-27 | ||
| JP12733395 | 1995-04-27 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2219303A1 true CA2219303A1 (en) | 1996-10-31 |
Family
ID=14957335
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002219303A Abandoned CA2219303A1 (en) | 1995-04-27 | 1996-04-25 | Method for formation of multi-layer coating film |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0823289B1 (en) |
| KR (1) | KR100412963B1 (en) |
| CA (1) | CA2219303A1 (en) |
| DE (1) | DE69623949T2 (en) |
| WO (1) | WO1996033814A1 (en) |
Families Citing this family (25)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11207255A (en) * | 1998-01-23 | 1999-08-03 | Kansai Paint Co Ltd | Method for multiple-layer top coating |
| WO1999052066A1 (en) | 1998-04-02 | 1999-10-14 | Swisscom Ag | Method for loading data onto chip cards and devices adapted thereto |
| US6248225B1 (en) | 1998-05-26 | 2001-06-19 | Ppg Industries Ohio, Inc. | Process for forming a two-coat electrodeposited composite coating the composite coating and chip resistant electrodeposited coating composition |
| US6423425B1 (en) | 1998-05-26 | 2002-07-23 | Ppg Industries Ohio, Inc. | Article having a chip-resistant electrodeposited coating and a process for forming an electrodeposited coating |
| US6180181B1 (en) | 1998-12-14 | 2001-01-30 | Ppg Industries Ohio, Inc. | Methods for forming composite coatings on substrates |
| CN100542691C (en) * | 2002-02-13 | 2009-09-23 | Ppg工业俄亥俄公司 | In substrate, form the paint line and the method for multi-layer composite coatings |
| DE60335979D1 (en) * | 2002-02-13 | 2011-03-24 | Ppg Ind Ohio Inc | RUBBER COATING ON A CARRIER |
| CN1460561B (en) * | 2002-02-28 | 2012-01-04 | 关西涂料株式会社 | Paint-applying method for car body |
| US20040028823A1 (en) * | 2002-08-08 | 2004-02-12 | Wilfried Dutt | Multi-layer coating process to achieve a highly saturated color appearance on a vehicle |
| JP5048337B2 (en) * | 2004-11-16 | 2012-10-17 | 日本ペイント株式会社 | Water-based colored paint, hydrophobic melamine resin aqueous dispersion and method for producing the same, water-based paint composition, and multilayer coating film forming method |
| US20060121205A1 (en) * | 2004-12-04 | 2006-06-08 | Basf Corporation | Primerless integrated multilayer coating |
| DE102005012056A1 (en) | 2005-03-16 | 2006-09-28 | Basf Coatings Ag | Multicoat paint systems, process for their preparation and their use in the automotive industry |
| US7910211B2 (en) † | 2005-06-20 | 2011-03-22 | E.I. Du Pont De Nemours And Company | Process for the production of multi-layer coatings |
| AU2006273254A1 (en) * | 2005-07-27 | 2007-02-01 | Nippon Paint Co., Ltd. | Water-based metallic coating composition and method of forming multilayered coating film |
| KR100694419B1 (en) * | 2005-10-10 | 2007-03-12 | 엘지전자 주식회사 | Method for high grossy painting using color primer mixture |
| DE102009007630A1 (en) * | 2009-02-05 | 2010-08-12 | Basf Coatings Ag | Coating agent for corrosion-resistant coatings |
| DE102009007629A1 (en) * | 2009-02-05 | 2010-08-12 | Basf Coatings Ag | Coating agent for corrosion-resistant coatings |
| DE102009007632A1 (en) | 2009-02-05 | 2010-08-12 | Basf Coatings Ag | Coating agent for corrosion-resistant coatings |
| JP5227881B2 (en) * | 2009-04-24 | 2013-07-03 | マツダ株式会社 | Multilayer coating structure |
| JP5663949B2 (en) * | 2010-05-18 | 2015-02-04 | マツダ株式会社 | Multilayer coating structure |
| BR112014005780A2 (en) * | 2011-09-13 | 2017-03-28 | Honda Motor Co Ltd | Multilayer coating film and multilayer coating film forming method |
| JP2014004552A (en) * | 2012-06-26 | 2014-01-16 | Kansai Paint Co Ltd | Method for forming multiple-layered coating film and coated product |
| JP2015066865A (en) * | 2013-09-30 | 2015-04-13 | マツダ株式会社 | Laminated coating film and coated article |
| KR101994073B1 (en) | 2019-03-13 | 2019-06-27 | 조현호 | Jigs for surface treatment of steering linkage equipment for vehicles |
| KR102532388B1 (en) | 2022-12-29 | 2023-05-15 | 주식회사 엠브이 | Painting method for injection products for vehicles |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5814266B2 (en) * | 1975-12-19 | 1983-03-18 | 三井東圧化学株式会社 | Metallic materials |
| US4755418A (en) * | 1985-08-12 | 1988-07-05 | Basf Corporation | Nonyellowing cathodic electrocoat |
| JPS62216671A (en) * | 1986-03-17 | 1987-09-24 | Nippon Paint Co Ltd | Metallic coating method |
| JP2614468B2 (en) * | 1987-11-26 | 1997-05-28 | 関西ペイント株式会社 | Top coat finish method |
| JPH0312263A (en) * | 1989-06-12 | 1991-01-21 | Nissan Motor Co Ltd | Method for forming urushi like film |
| JP2866415B2 (en) * | 1989-12-22 | 1999-03-08 | 関西ペイント株式会社 | Painting method |
| CA2104974C (en) * | 1990-02-09 | 2001-03-13 | San Chung Yuan | Method of improving the properties of coated reinforced thermoplastic articles and products obtained thereby |
| JPH04161274A (en) * | 1990-10-24 | 1992-06-04 | Kansai Paint Co Ltd | Method for painting steel plate |
| JPH05194811A (en) * | 1992-01-22 | 1993-08-03 | Dainippon Ink & Chem Inc | Resin composition and finish coating method using the same |
| JPH05269432A (en) * | 1992-03-27 | 1993-10-19 | Kansai Paint Co Ltd | Formation of coating film |
-
1996
- 1996-04-25 EP EP96912227A patent/EP0823289B1/en not_active Expired - Lifetime
- 1996-04-25 WO PCT/JP1996/001119 patent/WO1996033814A1/en active IP Right Grant
- 1996-04-25 CA CA002219303A patent/CA2219303A1/en not_active Abandoned
- 1996-04-25 DE DE69623949T patent/DE69623949T2/en not_active Expired - Fee Related
- 1996-04-25 KR KR1019970706888A patent/KR100412963B1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| DE69623949D1 (en) | 2002-10-31 |
| EP0823289A1 (en) | 1998-02-11 |
| KR19980703484A (en) | 1998-11-05 |
| KR100412963B1 (en) | 2004-04-03 |
| EP0823289A4 (en) | 1999-06-09 |
| DE69623949T2 (en) | 2003-02-20 |
| EP0823289B1 (en) | 2002-09-25 |
| WO1996033814A1 (en) | 1996-10-31 |
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