JP5988428B2 - Multi-component organic solvent-based undercoating composition and repair coating method using the same - Google Patents

Description

  The present invention relates to an organic solvent-based primer coating composition particularly useful for repair coating of automobiles and the like, and a repair coating method using the same.

  In general, repair coating of automobile skins, etc., is performed by removing the old paint film at the damaged part or sanding, then applying a plating putty on the spot with a spatula, etc., drying and polishing the putty surface. Apply the resin putty with a spatula to cover the old paint film around the part, polish the putty surface after drying, then apply primer surfacer coating and top coating sequentially on this, etc. Consists of.

  The putty-primer surfacer painting process is a process to remove the distortion of the damaged part and prepare the car body to its original shape. The putty type is applied to shallow scratches such as dots and lines. In addition, since each coated surface is polished step by step using a plurality of water-resistant papers having different grain sizes, a great amount of labor and time are spent.

  Therefore, the present applicant can spray-coat a coating composition containing an acrylic resin having a specific weight average molecular weight, a specific amount of pigment, resin fine particles, a large amount of polyisocyanate compound, and a specific amount of curing catalyst. It is found that it has a thick film forming property that can conceal the defective part (paper eyes due to insufficient polishing, etc.), and it is proposed that the putty process and polishing work can be greatly simplified by using this as a primer surfacer did.

  By the way, the conventional automobile repair painting process is a three-coat two-bake in which after the primer surfacer coating, drying and polishing are performed, the color base coating is applied to the polished surface, and the resulting color base coating is dried after clear coating. It has become mainstream. In this case, the primer surfacer painting process is not only a painting process, but also a drying process and a polishing process, and thus a lot of work time is spent.

  Therefore, when a solvent-based or water-based color base is applied wet-on-wet after conventional primer surfacer coating, the final finish is not satisfactory, and primer surfacer adhesion strength is also difficult, There is a need for the development of an undercoating composition that does not affect the appearance of the overcoating of the next process or the performance as a repair coating even if the drying or polishing process is reduced or omitted.

JP 2002-173632 A

  An object of the present invention is to provide an undercoating composition and an undercoating composition which can form an undercoating film having moderate adhesion strength and smoothness, and can reduce the time required for the entire coating including the overcoating in the next step. The purpose of this invention is to provide a repair coating method using the above.

  As a result of intensive studies on the above-mentioned problems, the present inventors have determined that a specific pigment composition, particularly talc, as a composition obtained by combining a main ingredient component containing an acrylic polyol and a pigment and a curing agent component containing a polyisocyanate compound. By using a small amount, the inventors have found that the adhesive strength to the top coat film is excellent, and that a satisfactory finish can be obtained even when a color base paint in the next step is applied.

That is, the present invention
1. A multi-component organic solvent-based undercoat coating composition obtained by mixing a main component (I) and a curing agent component (II),
The main agent component (I) contains the acrylic polyol (A), the pigment composition (B) and the organic solvent (C), the curing agent component (II) contains a polyisocyanate compound,
The pigment composition (B) contained in the main component (I) contains talc, barium sulfate and calcium carbonate as a part of the components, and the content of the pigment composition (B) is acrylic polyol (A) solid content 100 The amount of talc contained in the pigment composition (B) is in the range of 50 to 500 parts by mass based on 100 parts by mass, and 0.01 to 55 parts by mass based on 100 parts by mass of the acrylic polyol (A) solid content. range near parts is, the main agent component (I) is are those further comprising an amide-based viscosity modifier, the amount of acrylic polyol (a) 100 parts by weight of the solid content of the active ingredient of the amide-based viscosity modifier Undercoat paint composition characterized by being in a range of 0.1 to 15 parts by mass as a reference ,
2. The undercoat paint composition according to 1, wherein the pigment composition (B) further comprises a color pigment,
3. In addition to the main component (I) and the curing agent component (II), the polyol component (III) is a multi-component system, wherein the polyol component (III) contains a polyol compound, and the pigment content is polyol. The undercoat coating composition according to item 1 or 2, wherein the composition is less than 50 parts by mass based on 100 parts by mass of the compound solids or substantially free of pigment.
4). 4. The base coating composition according to any one of items 1 to 3 is applied to a repair site that may be putty-coated, and a colored base coating is applied in a state where the coating film by the base coating composition is uncured. A repair coating method characterized by including a step of coating the composition;
5. 4. The undercoat paint composition according to any one of items 1 to 3 is applied to a repaired part which may be putty-coated, and the topcoat colored paint is applied in a state where the coating film by the undercoat paint composition is uncured. The present invention relates to a repair coating method characterized by comprising a step of applying a composition, applying a top clear paint in an uncured state of the overcoat coloring paint composition, and drying.

  Since the undercoat paint composition of the present invention has an appropriate thickness, is excellent in smoothness, and can form an undercoat film having high adhesion strength to the topcoat film, this is applied as an undercoat, By applying a solvent-based or water-based top coating composition, it is possible to form a repair coating film having an excellent appearance with little influence of the base. It is also possible to wet-on-wet the base coating composition and the top coating composition to obtain a repaired coating with a natural appearance, greatly reducing the total work time and energy required for repair coating. It can be omitted.

  The undercoat coating composition of the present invention is a multi-component composition obtained by mixing the main component (I) and the curing agent component (II). Hereinafter, it demonstrates in order.

  First, the main component (I) will be described.

<Acrylic polyol (A)>
In the present invention, as the acrylic polyol (A) that is contained in the main component (I) and can be a polyurethane film forming component together with the polyisocyanate compound described later, conventionally known ones can be used without limitation, and the organic solvent dilutability. For example, it may be a copolymer of a polymerizable unsaturated monomer containing a hydroxyl group-containing polymerizable unsaturated monomer as an essential component and containing at least one (meth) acryloyl group monomer.

  Examples of the hydroxyl group-containing polymerizable unsaturated monomer include hydroxyalkyl (meth) such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate. Acrylate, ε-caprolactone modified form of the above hydroxyalkyl (meth) acrylate, hydroxyl group-containing (meth) acryloyl monomer such as polyoxyethylene chain-containing (meth) acrylate having a hydroxyl group at the molecular end; These can be used alone or in combination of two or more.

  Examples of the polymerizable unsaturated monomer copolymerized with the hydroxyl group-containing polymerizable unsaturated monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl. Linear or branched alkyl (meth) acrylates such as (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate; cyclohexyl (Meth) acrylate, cycloaliphatic alkyl (meth) acrylate such as isobornyl (meth) acrylate; Aralkyl (meth) acrylate such as benzyl (meth) acrylate; 2-methoxyethyl (meth) acrylate, 2-ethoxy Alkoxyalkyl (meth) acrylates such as ethyl (meth) acrylate; perfluoroalkyl (meth) acrylates; N, N-dialkylaminoalkyl (meth) acrylates such as N, N-diethylaminoethyl (meth) acrylate; (meth) Acrylamide; allyl (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, trimethylolpropane tri (Meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, pentaerythrito Rudi (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerol di (meth) acrylate, 1,1,1-trishydroxymethylethanedi (meth) acrylate, 1,1,1-trishydroxymethylethanetri (meta ) (Meth) acryloyl monomer having at least two polymerizable unsaturated groups in one molecule such as acrylate, 1,1,1-trishydroxymethylpropane tri (meth) acrylate ;; (meth) acrylic acid; acetoacetoxy Carbonyl group-containing (meth) acryloyl monomers such as ethyl (meth) acrylate and diacetone (meth) acrylamide; glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate Epoxy group-containing (meth) acryloyl monomers such as 3,4-epoxycyclohexylethyl (meth) acrylate and 3,4-epoxycyclohexylpropyl (meth) acrylate; Isocyanato group-containing (meth) such as isocyanatoethyl (meth) acrylate Acrylyl monomer; alkoxysilyl group-containing (meth) acryloyl monomer such as γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltriethoxysilane; dicyclopentenyloxyethyl (meth) acrylate, dicyclopentenyloxypropyl (meth) Examples include acrylate, dicyclopentenyl (meth) acrylate and other oxidatively curable group-containing (meth) acryloyl monomers. These may be used alone or in combination of two or more. It is possible to use.

  Examples of other polymerizable unsaturated monomers that can be copolymerized other than (meth) acryloyl monomers include (meth) acrylonitrile; vinyl ester compounds such as vinyl acetate and vinyl propionate; styrene, α-methylstyrene, and the like. Vinyl aromatic compounds; polyvinyl compounds having at least two polymerizable unsaturated groups in one molecule such as triallyl isocyanurate, diallyl terephthalate, and divinylbenzene; carboxyls such as maleic acid, crotonic acid, and β-carboxyethyl acrylate Group-containing polymerizable unsaturated monomer; (meth) acrolein, formylstyrene, carbonyl group such as vinyl alkyl ketone having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone, etc.), acetoacetoxy allyl ester, etc. Containing polymerization Unsaturated unsaturated monomers; Epoxy group-containing polymerizable unsaturated monomers such as allyl glycidyl ether; Isocyanato group-containing polymerizable unsaturated monomers such as m-isopropenyl-α, α-dimethylbenzyl isocyanate; Vinyltrimethoxysilane, vinyltriethoxy An alkoxysilyl group-containing polymerizable unsaturated monomer such as silane; an epoxy group-containing polymerizable unsaturated monomer or an oxidation-curable group-containing polymerizable unsaturated monomer such as a reaction product of a hydroxyl group-containing polymerizable unsaturated monomer and an unsaturated fatty acid These may be used alone or in combination of two or more.

  The acrylic polyol (A) has a weight average molecular weight in the range of 5,000 to 80,000, preferably 6,000 to 70,000, and a solid content hydroxyl value of 200 mgKOH / It is suitable that it is not more than g, preferably in the range of 50 to 150 mg / KOH.

  In this specification, the weight average molecular weight is a value obtained by converting the weight average molecular weight measured by gel permeation chromatograph (“HLC8120GPC” manufactured by Tosoh Corporation) based on the weight average molecular weight of polystyrene. Columns are “TSKgel G-4000H × L”, “TSKgel G-3000H × L”, “TSKgel G-2500H × L”, “TSKgel G-2000H × L” (both manufactured by Tosoh Corporation, trade names) ), Mobile phase: tetrahydrofuran, measurement temperature: 40 ° C., flow rate: 1 ml / min, detector: RI.

  It is suitable that the acrylic polyol (A) is contained in the resin solids contained in the main component (I) at 75% by mass or more, preferably 85% by mass or more.

<Pigment composition (B)>
In the present invention, the pigment composition (B) contained in the main component (I) contains talc, barium sulfate and calcium carbonate as extender pigments.

  In the present invention, as talc, barium sulfate and calcium carbonate, those known as extender pigments in the paint field and the like can be used, which may be synthetic or natural, and the surface may be changed as necessary. It may be processed. Moreover, there is no restriction | limiting also in the shape and magnitude | size.

  Moreover, content of the talc contained in a pigment composition (B) exists in the range of 0.01-55 mass parts on the basis of 100 mass parts of acrylic polyol (A) solid content contained in a main ingredient component (I). It is characterized by that.

  In the present invention, the undercoating composition contains talc, and the adhesion strength of the undercoating film formed when the talc content is within this range is significantly improved, so that the overcoating in the next process is wet.・ It can be turned on and wet.

  In this invention, as preferable content of the talc based on 100 mass parts of acrylic polyol (A) solid content, it is 0.1-35 mass parts, Preferably it is 0.5-30 mass parts.

  Moreover, when the said pigment composition (B) further contains barium sulfate and calcium carbonate in addition to talc as an extender, the finished external appearance when the top coat which is the next process is applied can be good.

As a preferable blending amount based on 100 parts by weight of solid content of acrylic polyol (A) of barium sulfate and calcium carbonate,
Barium sulfate is 20 to 200 parts by mass, more preferably 30 to 150 parts by mass, and calcium carbonate is 30 to 250 parts by mass, and more preferably 50 to 200 parts by mass.

  Moreover, the said pigment composition (B) can contain well-known pigments, such as extender pigments other than talc, barium sulfate, and calcium carbonate, a coloring pigment, and a rust preventive pigment as needed.

  Among these, other extender pigments include, for example, barium carbonate, aluminum silicate, gypsum, clay, silica, white carbon, diatomaceous earth, magnesium carbonate, alumina white, gloss white, mica powder and the like.

  Examples of the color pigment include white pigments such as titanium dioxide; black pigments such as carbon black, acetylene black, lamp black, bone black, graphite, iron black, and aniline black; yellow iron oxide, titanium yellow, monoazo yellow, Yellow pigments such as condensed azo yellow, azomethine yellow, bismuth vanadate, benzimidazolone, isoindolinone, isoindoline, quinophthalone, benzidine yellow, permanent yellow; orange pigments such as permanent orange; red iron oxide, naphthol AS azo red, Ansanthrone, Anthraquinonyl Red, Perylene Maroon, Quinacridone Red Pigment, Diketopyrrolopyrrole, Watching Red, Permanent Red, etc. Red Pigment; Cobalt Purple, Quinacridone Violet, Geo Purple pigments such as sajin violet; Blue pigments such as cobalt blue, phthalocyanine blue and selenium blue; Green pigments such as phthalocyanine green; Metallic pigments such as aluminum powder, bronze powder, copper powder, tin powder, iron phosphide and zinc powder; Examples thereof include pearlescent pigments such as metal oxide-coated mica powder and mica-like iron oxide, and these pigments can be used alone or in combination of two or more.

  When the undercoating composition of the present invention contains a color pigment, the color pigment has a mass of 1 or more and less than 100 parts by mass, preferably 5 to 80 parts by mass, based on a total of 100 parts by mass of talc, barium sulfate and calcium carbonate. More preferably, it is in the range of 15 to 35 parts by mass from the viewpoint of thick coatability and the finished appearance of the top coat.

  In the present invention, the content of the pigment composition (B) is 50 to 500 masses of the pigment composition (B) based on 100 mass parts of the acrylic polyol (A) resin solid content contained in the main component (I). Part, preferably in the range of 100 to 400 parts by weight, is suitable from the viewpoint of the adhesion strength of the undercoat film and the finished appearance after top coating.

<Organic solvent (C)>
In the present invention, examples of the organic solvent (C) include organic compounds having a molecular weight in the range of 58 to 220, particularly 72 to 200, and those known in the paint field can be used without limitation. For example, it is desirable to include at least one organic solvent selected from an ester organic solvent and a ketone organic solvent.

  Examples of such ester organic solvents include ethyl acetate, butyl acetate, isobutyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate, 3-methoxybutyl acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate. , Diethylene glycol monoethyl ether acetate and the like, and examples of ketone organic solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethyl isoamyl ketone, diisobutyl ketone, methyl hexyl ketone, and isophorone. It can be used alone or in combination of two or more.

  The amount of at least one organic solvent selected from such ester organic solvents and ketone organic solvents is 5% by mass or more, particularly 20% by mass, based on the total organic solvent contained in the primer coating composition of the present invention. It is desirable to be above.

  In the present invention, other organic solvents other than the ester organic solvents and ketone organic solvents include n-butane, n-hexane, n-heptane, n-pentane, n-octane, n-nonane, n-decane, linear alkanes such as n-undecane, n-dodecane, n-tridecane, n-tetradecane, n-pentadecane, n-hexadecane, n-heptadecane; 2-methylbutane, 2,2-dimethylpropane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, 2-methylhexane, 3-methylhexane, 2,3-dimethylpentane, 2,4-dimethylpentane, 2,2,3-trimethyl Pentane, 2,2,4-trimethylpentane, 3,4-diethylhexane, 2,6-dimethyloctane, 3,3-di Tyloctane, 3,5-dimethyloctane, 4,4-dimethyloctane, 3-ethyl-3-methylheptane, 2-methylnonane, 3-methylnonane, 4-methylnonane, 5-methylnonane, 2-methylundecane, 3-methylundecane Branched alkanes such as 2,2,4,6,6-pentamethylheptane; cyclopentane, t-decalin, cyclohexane, methylcyclohexane, ethylcyclohexane, 1,2-dimethylcyclohexane, 1,3-dimethylcyclohexane, 1 , 4-dimethylcyclohexane, propylcyclohexane, isopropylcyclohexane, 1,2-methylethylcyclohexane, 1,3-methylethylcyclohexane, 1,4-methylethylcyclohexane, 1,2,3-trimethylcyclohexane, 1,2 Aliphatic hydrocarbon organic solvents such as cyclic alkanes such as 4-trimethylcyclohexane and 1,3,5-trimethylcyclohexane; aromatic hydrocarbon organic solvents such as toluene and xylene; dioxane, tetrahydrofuran, ethylene glycol monomethyl ether, Ethylene glycol monoethyl ether, ethylene glycol mono n-propyl ether, ethylene glycol monoisopropyl ether, ethylene glycol mono n-butyl ether, ethylene glycol monoisobutyl ether, ethylene glycol mono tert-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol Mono n-propyl ether, diethylene glycol monoisopropyl ether, Diethylene glycol mono n-butyl ether, diethylene glycol monoisobutyl ether, diethylene glycol mono tert-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono n-propyl ether, propylene glycol monoisopropyl ether, dipropylene glycol monomethyl ether, dipropylene Ether organic solvents such as glycol monoethyl ether, dipropylene glycol mono n-propyl ether, dipropylene glycol monoisopropyl ether, methanol, isopropanol, tert-butanol, secondary butanol, isobutanol, n-butanol, 2-ethylhexanol, n-Octanol, Ben It can be exemplified an alcohol-based organic solvent such as alcohol.

  The organic solvent (C) can be blended as a polymerization solvent and dilution solvent in the production of the acrylic polyol (A), or for dilution in the production of the main component (I).

<Main ingredient component (I)>
As the main component (I), in addition to the acrylic polyol (A), the pigment composition (B) and the organic solvent (C), a viscosity modifier, a curing catalyst, cellulose acetate butyrate and a modified product thereof, a polyester resin, Additives for coating materials such as modifying resins other than acrylic polyol (A) such as alkyd resins and polyurethane resins, pigment dispersants, surface conditioners, and resin particles can be appropriately blended.

  Of these, conventionally known viscosity modifiers can be used, but amide viscosity modifiers are particularly preferred.

  By using an amide-based viscosity modifier, the storage stability of the main component (I) and the coating workability of the primer coating composition of the present invention are improved, and the adhesion strength to the top coating film of the primer coating composition Has the effect of improving.

  As such an amide-based viscosity modifier, those known in the paint field can be used without limitation, and the synthesis method, materials used, etc. are not particularly limited, and commercially available products can also be used.

  Specifically, fatty acid monoamides synthesized by dehydration of fatty acid ammonium salts or ammonolysis of fats and oils (esters); condensation reaction of fatty acid amide and formaldehyde, heat condensation reaction of monocarboxylic acid and diamine, or dibasic acid and monoamine Fatty acid diamide (bisamide) synthesized by heat condensation reaction with diamine; obtained by polycondensation of dibasic acid and diamine, polycondensation of diamine derivative and dibasic acid, dimerization of diamine and dibasic acid derivative or unsaturated fatty acid And fatty acid polyamides obtained by polycondensation of dimer acid or ring-opening polymerization of lactam.

  Such an amide viscosity modifier may be diluted with a diluent medium such as an organic solvent. In the present invention, the content of the active ingredient (component other than the dilution medium) of the amide-based viscosity modifier is 0.1 to 15 parts by mass, preferably 100 parts by mass of the solid content of the acrylic polyol (A), preferably Is preferably in the range of 0.5 to 8 parts by mass.

  Further, as the curing catalyst, a conventionally known urethanization catalyst can be applied without particular limitation. For example, bismuth nitrate, lead oleate, tin octylate, dibutyltin dilaurate, dibutyltin bis (acetylacetonate), titanium tetrachloride, Examples thereof include metal compounds such as dibutyl titanium chloride, tetrabutyl titanate, iron trichloride, and zinc octylate, and tertiary amines.

  The curing catalyst may be contained in any of the main agent component (I), the curing agent component (II), and the clear composition (III) described later. The content is 0.01 to 10 parts by mass, preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the solid content of the acrylic polyol (A), and the curability of the composition of the present invention and the main ingredient component. It is suitable from the viewpoint of suppressing increase in viscosity after mixing (I) and curing agent component (II).

  The main ingredient component (I) can have a low viscosity relative to the solid content concentration, and can exhibit excellent coating workability. Specifically, the viscosity in the storage state (sealed can state) can be in the range of 75 to 140 KU, particularly 80 to 120 KU.

  In this specification, it is assumed that the viscosity of the sample adjusted to 25 ° C. is measured with a Stormer viscometer.

<Polyisocyanate compound (D)>
In the present invention, the polyisocyanate compound (D) is a polyisocyanate compound having 2 or more, preferably 3 isocyanate groups in one molecule. Specific examples thereof include hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, xylylene diisocyanate, meta-tetramethylxylylene diisocyanate, tolylene diisocyanate, 4,4 ′. -Polyisocyanate compounds such as diphenylmethane diisocyanate and lysine diisocyanate, or adducts of these polyisocyanates with polyhydric alcohols, low molecular weight polyester resins or water, or the cyclization weight of each polyisocyanate as described above. Examples thereof include an isocyanate and a biuret body, and these may be used alone or in combination of two or more.

<Curing agent component (II)>
In the present invention, the curing agent component (II) contains the polyisocyanate compound (D), and an organic solvent; paint additives such as a viscosity modifier, a curing catalyst, and a surface modifier are blended as necessary. can do.

<Polyol component (III)>
The undercoat coating composition of the present invention is obtained by mixing the main component (I) and the curing agent component (II) immediately before coating, and if necessary, the polyol component (III) may be further combined. it can.

  By constituting the undercoating composition with a multi-component system of main component (I), curing agent component (II) and polyol component (III), the storage stability of each component is good and the undercoating composition of the present invention is used. Even if the undercoat paint film formation process with the composition and the top coat coloring paint composition coating process, which is the next process, are applied wet-on-wet, or the polishing process is omitted or shortened, a coating film with excellent finished appearance can be obtained. Has the effect of forming.

  In the present invention, as the polyol component (III), a polyol compound is essential, and other components are included as necessary. Examples of the polyol compound include acrylic polyol, polyester polyol, polyurethane polyol, cellulose acetate butyrate and Conventionally known polyol compounds such as modified products thereof can be mentioned, and these polyol compounds can be used alone or in combination of two or more.

  As the polyol compound, an acrylic polyol is suitable from the viewpoint of miscibility with the main component (I). The acrylic polyol (E) contained in the polyol component (III) can be appropriately selected from those exemplified in the description of the acrylic polyol (A) described above, and the polyol compound (A) can be selected from the polyol compound (A). ) May be used.

  In the present invention, the polyol component (III) is different from the main component (I) in that the blending amount of the pigment is less than 50 parts by mass based on 100 parts by mass of the solid content of the polyol compound. In the polyol component (III), the amount of the pigment based on the polyol compound solid content of 100 parts by mass is less than 20 parts by mass, preferably less than 0.5 parts by mass, or substantially free of pigment. This is suitable from the viewpoint of the finished appearance in the wet-on-wet coating process.

  The solid content concentration of the polyol component (III) is generally adjusted to 10 to 70% by mass, preferably 20 to 60% by mass.

  Further, the polyol component (III) contains the curing catalyst from the viewpoint of the undercoat / topcoat adhesion during wet-on-wet coating with the topcoat in the next step and the curability of the formed undercoat. It is desirable.

  The content of the curing catalyst is in the range of 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the solid content of the polyol compound contained in the polyol component (III). Is suitable.

  Further, the polyol component (III) can contain coating additives such as an organic solvent, a viscosity modifier, a pigment dispersant, a surface modifier, and resin particles as necessary.

  As an organic solvent, it can select from the compound illustrated by description of the said organic solvent (C) suitably, and can use it.

<Undercoat paint composition>
In the present invention, the main agent component (I) and the hardener component (II) are mixed with 0.8 equivalent of an isocyanate group in the hardener component (II) with respect to 1 equivalent of a hydroxyl group in the main agent component (I). It is suitable to mix | blend so that it may become a ratio of 4.0 equivalent, preferably 1.0-3.5 equivalent.

  Further, when the undercoat coating composition of the present invention is composed of the main agent component (I), the curing agent component (II) and the polyol component (III), it is contained in the main agent component (I) and the polyol component (III). It is suitable to blend so that the isocyanate group in the curing agent component (II) is 0.5 to 3.0 equivalent, preferably 0.7 to 2.5 with respect to 1 equivalent of the hydroxyl group.

  Further, when the undercoat composition of the present invention is a three-component system of component (I), component (II) and component (III), the mass of polyol component (III) based on 100 parts by mass of the main component is 10 to 10 parts. It is suitable to be in the range of 80 parts by weight, preferably 15-60 parts by weight.

  The composition of the present invention thus obtained is a two-component composition or a three-component composition in which each component is stored separately. In general, each component is mixed immediately before coating, and if necessary, a diluted thinner is used. The viscosity is adjusted before use.

  The present invention further provides a repair coating method using the above composition for base coating.

  The repair coating film applicable to the method of the present invention includes, for example, a coating film coated on an outer plate part of an automobile or a household electric appliance, and this may be an undercoating film or an intermediate coating film (may be omitted) ) And a top coat film in many cases. The coating film may be either a solid type or a metallic type. These coating films may be three-dimensional crosslinked cured coating films or non-crosslinked coating films.

  In the method of the present invention, first, a damaged portion of the coating film is scraped off, and sanding is performed around the damaged portion as necessary, and then degreased as necessary. The present composition can be directly applied to the degreased portion if it is a line scar or a scratch, etc., and depending on the damage, the composition of the present invention can be applied after filling the scraped portion with various putty. . The putty can be filled by a method known per se by using a spatula. Examples of the putty include conventionally known plating putty and resin putty, and examples thereof include nitrified cotton, acrylic resin, epoxy acrylate resin, unsaturated polyester resin, and urethane resin. When the putty is applied, it is preferable to dry the putty and then polish the putty surface. However, since the composition of the present invention has a good base concealing property, the polished surface may be rough.

  For the coating of the composition of the present invention, a conventionally known coating method can be adopted, and spray coating is particularly suitable. The coating film thickness is in the range of 50 to 500 μm in terms of dry film thickness, and thick film coating is possible.

  Drying conditions are, for example, 5 to 40 ° C., preferably 10 to 30 ° C., and can be performed for 20 to 120 minutes, particularly 30 to 90 minutes.

  According to the present invention, even if the coating formed by the undercoat coating composition is uncured and overcoating in the next step, it has the advantage of having little influence on the finished appearance of the topcoat, It does not exclude drying and polishing of the undercoat film.

  The top coat may be a conventionally known coating such as a one-coat finish using only a colored base paint formed by blending a metallic pigment and / or a colored pigment, or a two-coat finish using the colored base paint and a clear paint. Can be mentioned.

  As the colored base paint, organic solvent-based and water-based top-coat paints that are usually used for repair can be used without any particular restrictions, and they are applied by known coating means such as spray painting, electrostatic painting, brush painting, roller painting, etc. be able to.

  In the case where the colored base paint is applied a plurality of times, steps such as flash-off (the coated film is allowed to stand at room temperature), air blowing, preheating, etc. may be provided between the respective coatings as necessary.

  Drying after the completion of the application of the colored base paint is not particularly limited, and may be in an uncured state when the top clear is reapplied. In general, it is preferable to dry for 5 to 60 minutes, for example, at a temperature of 20 to 100 ° C. The film thickness can be appropriately adjusted according to the state of the surface to be coated, but generally a dry film thickness of 5 to 100 μm, particularly 10 to 60 μm is suitable.

  As the top clear coating, conventionally known ones can be used without any particular limitation. For example, acrylic resin or fluorine resin containing a crosslinkable functional group such as a hydroxyl group is the main agent, and block polyisocyanate, polyisocyanate, melamine resin, or the like is a curing agent. Curable paints contained as lacquer paints mainly composed of cellulose acetate butyrate modified acrylic resin, etc. can be suitably used, and if necessary, pigments, fiber derivatives, additive resins, UV absorbers, It can contain paint additives such as a light stabilizer, a surface conditioner, and a curing catalyst.

  The top clear coating is preferably dried at a temperature of 20 to 100 ° C., preferably 40 to 100 ° C., for 5 to 60 minutes. The film thickness can be appropriately adjusted according to the state of the surface to be coated, but generally a dry film thickness of 5 to 100 μm, particularly 10 to 60 μm is suitable.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to only these examples. In the following examples, “part” and “%” mean “part by mass” and “% by mass”, respectively.

<Manufacture of two-component undercoat coating composition>
Example 1
30 parts of acrylic resin solution (Note 1) with a solid content of 55%, 10 parts of butyl acetate, 1.9 parts of pigment dispersant, 10 parts of titanium white, 1 part of talc, 15 parts of barium sulfate, 29 parts of calcium carbonate, dibutyltin 0.1 part of dilaurate and 3 parts of amide thickener (fatty acid amide, amide viscosity modifier, active ingredient 20%) were sequentially blended, mixed and stirred, and dispersed for 30 minutes to obtain a main ingredient component. 40 parts of a polyisocyanate compound (“Sumijour N3390EA”, trade name, manufactured by Sumika Bayer Urethane Co., Ltd.) as a curing agent is mixed with 100 parts of the main component immediately before use to obtain a coating composition for undercoat (A-1). It was.
(Note 1) Acrylic resin solution A reaction vessel was charged with 52 parts of butyl acetate, heated to 110 ° C. with stirring, 10 parts of styrene, 10 parts of methyl methacrylate, 5 parts of n-butyl methacrylate, 60 parts of i-butyl methacrylate. A monomer mixture of 1 part of methacrylic acid, 14 parts of 2-hydroxyethyl methacrylate and 2.3 parts of azobisisobutyronitrile and a monomer mixture of polymerization initiator at 110 ° C. or lower using a dropping pump over 3 hours It was dripped at a constant speed. After completion of dropping, the temperature was kept at 110 ° C. for 60 minutes and stirring was continued. Thereafter, a solution prepared by dissolving 0.5 part of azobisisobutyronitrile in 7 parts of butyl acetate as an additional catalyst was dropped at a constant rate over 60 minutes. And after completion | finish of dripping, it hold | maintained at 110 degreeC for 60 minutes, and reaction was complete | finished. The obtained hydroxyl group-containing acrylic resin solution was a uniform yellow transparent solution having a nonvolatile content of 55%, and the weight average molecular weight of the resin was 18000 and the hydroxyl value was 60 mgKOH / g.

Examples 2-6 and Comparative Examples 1-4
In the said Example 1, except having set it as the compounding composition of Table 1, it is the same as Example 1, and each coating composition for undercoats (A-2)-(A-6) and (A-16)-(A- 19) was obtained.

<Manufacture of three-component undercoat coating composition>
Examples 7-15
In the formulation shown in Table 1, the main component, the curing agent component, and the clear composition were mixed immediately before use to obtain the respective undercoat coating compositions (A-7) to (A-15).

(Note 2) 3547.5 parts of deionized water and 40 parts of “Latemul S-120A” (manufactured by Kao Corporation, sulfosuccinic acid-based allyl group-containing anionic reactive emulsifier, 50% aqueous solution) are added to the resin fine particle reaction vessel. The temperature was raised to 90 ° C. with stirring. Next, 20% of an aqueous solution obtained by dissolving 12.5 parts of “VA-086” (manufactured by Wako Pure Chemical Industries, Ltd., water-soluble azoamide polymerization initiator) in 500 parts of deionized water was added thereto. After 15 minutes, 5% of a monomer mixture consisting of 300 parts of styrene, 400 parts of methyl methacrylate, 200 parts of n-butyl acrylate, and 100 parts of 1,6-hexanediol diacrylate was added and stirred for 30 minutes. Thereafter, dropping of the remaining monomer mixture and aqueous polymerization initiator solution was started, dropping of the monomer mixture was performed for 3 hours, and dropwise addition of the polymerization initiator aqueous solution was performed for 3.5 hours, and the temperature was maintained at 90 ° C. After completion of the dropwise addition of the polymerization initiator aqueous solution, the mixture was kept at 90 ° C. for 30 minutes, cooled to room temperature, and taken out using a filter cloth to obtain an aqueous gelled fine particle polymer aqueous dispersion having a solid content of 20%. Its particle size was 72 nm. This was dried on a stainless steel pad to obtain resin fine particles.

(Note 3) Clear composition 40 parts of an acrylic resin solution (Note 1), 59.7 parts of butyl acetate, 0.2 part of dibutyltin dilaurate and 0.1 part of a surface conditioner are mixed in a stirring and mixing container. Thus, a clear composition was obtained.

<Performance test>
(*) Adhesion test Each of the undercoat paint compositions obtained in the above Examples and Comparative Examples was spray-coated on a 300 × 100 × 0.8 mm mild steel plate so that the dry film thickness was 60 μm, and then 20 ° C. , Air spray so that the dry film thickness is 15 μm on the cured coating film dried for 60 minutes, lettan PG Hybrid Eco # 202 Sun Metallic Base (product name, one-pack type automotive coating top coating, manufactured by Kansai Paint Co., Ltd.) Painted with. On the uncured coating film left at room temperature for 5 minutes after coating, lettan PG Eco HX (Q) clear (trade name, two-pack top clear paint for automobile repair, manufactured by Kansai Paint Co., Ltd.) as a dry film thickness of 40 μm It was painted with air spray. After leaving at room temperature for 10 minutes, it was heated at 60 ° C. for 20 minutes using a hot-air circulating drying oven to obtain a test plate. A cross cut test based on JIS K5600 was performed on this test coated plate. Specifically, 100 cuts reaching the material in a grid pattern at intervals of 2 mm in the vertical and horizontal directions are put on the coating film, and an adhesive tape having an adhesion force (120 gf / 10 mm) is applied. And this adhesive tape was peeled off instantaneously, the quantity of the coating film piece which peeled and adhered to the adhesive tape was investigated, and the following reference | standard evaluated.
○: No peeling between the primer coating and the metallic base coating,
Δ: Less than 10% peeling between the undercoat coating and the metallic base coating
X: 10% or more of peeling between the undercoat coating film and the metallic base coating film.

(*) “LUC Poly Putty” (unsaturated polyester putty, manufactured by Kansai Paint Co., Ltd.) was placed on a mild steel plate having a finished appearance of 300 × 100 × 0.8 mm with a spatula to a thickness of about 2 mm, and 60 ° C. at 60 ° C. After drying for a minute, the coated surface is polished so that the surface is smoothed with P120 air sharpening paper, and then each primer coating composition obtained in Examples and Comparative Examples on the coated surface is used as a primer surfacer. Prepared to be 50% solid content when diluted with diluted thinner, spray-coated to a dry film thickness of about 50 μm, and then allowed to stand at 20 ° C. for 10 minutes. # 202 Sun Metallic Base (trade name, 1-pack type automotive repair top coat, manufactured by Kansai Paint Co., Ltd.) was applied by air spray to a dry film thickness of 15 μm. On the uncured coating film left at room temperature for 5 minutes after coating, lettan PG Eco HX (Q) clear (trade name, two-pack top clear paint for automobile repair, manufactured by Kansai Paint Co., Ltd.) as a dry film thickness of 40 μm It was painted with air spray. After leaving at room temperature for 10 minutes, it was heated at 60 ° C. for 20 minutes using a hot-air circulating drying oven to obtain a test plate. Thereafter, the appearance of each test coated plate was observed from the direction of the skew (diagonal direction) and evaluated according to the following evaluation criteria. ◎: Excellent gloss and smoothness on the coating surface. Absent,
○: Glossiness and smoothness of the coating surface are good, and neither suction marks nor prassuff marks are observed.
Δ: Glossiness and smoothness of the coating surface are slightly poor, and neither suction marks nor prassuff marks are observed.
X: The glossiness and smoothness of the coating surface are poor, and either a suction mark or a prassuff mark is observed.

Claims (5)

A multi-component organic solvent-based undercoat coating composition obtained by mixing a main component (I) and a curing agent component (II),
The main agent component (I) contains the acrylic polyol (A), the pigment composition (B) and the organic solvent (C), the curing agent component (II) contains a polyisocyanate compound,
The pigment composition (B) contained in the main component (I) contains talc, barium sulfate and calcium carbonate as a part of the components, and the content of the pigment composition (B) is acrylic polyol (A) solid content 100 The amount of talc contained in the pigment composition (B) is in the range of 50 to 500 parts by mass based on 100 parts by mass, and 0.01 to 55 parts by mass based on 100 parts by mass of the acrylic polyol (A) solid content. range near parts is, the main agent component (I) is are those further comprising an amide-based viscosity modifier, the amount of acrylic polyol (a) 100 parts by weight of the solid content of the active ingredient of the amide-based viscosity modifier Undercoat paint composition characterized by being in the range of 0.1 to 15 parts by mass as a reference . The undercoat paint composition according to claim 1, wherein the pigment composition (B) further comprises a color pigment. In addition to the main component (I) and the curing agent component (II), the polyol component (III) is a multi-component system, wherein the polyol component (III) contains a polyol compound, and the pigment content is polyol. The undercoat paint composition according to claim 1 or 2, which is less than 50 parts by mass based on 100 parts by mass of the compound solids or substantially free of pigment. A base coating composition according to any one of claims 1 to 3 is applied to a repair site that may be putty-coated, and a colored base coating is applied in a state where the coating film of the base coating composition is uncured. A repair coating method comprising a step of coating a composition. The undercoat paint composition according to any one of claims 1 to 3 is applied to a repaired part that may be putty-coated, and the topcoat colored paint is applied in a state where the coating film of the undercoat paint composition is uncured. A repair coating method comprising a step of applying a composition, applying a top clear paint in an uncured state of the top coat coloring paint composition, and drying.