JP2019085463A - Multicomponent-based primer composition - Google Patents

Abstract

To provide a primer composition suitable for forming a coated film good in finish skin of a coating patch part.SOLUTION: There is provided an organic solvent type multicomponent-based primer composition obtained by mixing a main agent component (I) and a hardening agent component (II), in which the main agent component (I) contains acrylpolyol (A1), a pigment composition (A2) and an organic solvent (A3), the hardening agent component (II) contains a polyisocyanate compound, the pigment composition (A2) contained in the main agent component (I) contains a loading pigment as a part of the component, the main agent component (I) and/or the hardening agent component (II) contains a silica fine particle (A4) of 5 to 80 pts.mass based on 100 pts.mass of an acrylpolyol (A1) nonvolatile component.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a multicomponent primer coating composition which is particularly suitable for substrate formation for coating large scale machines.

  A large vehicle such as a railway vehicle or a truck or bus can bear a heavy load, so there is a thickness of a constituent base compared to a general passenger car. In the case of coating such a large vehicle as a substrate, there is a problem that the heat is not sufficiently transmitted to the substrate in the heating furnace and the coating film becomes insufficiently cured. For this reason, in the coating of a large vehicle, the heat-curable coating composition generally used in the coating of ordinary passenger cars, industrial products and the like can not be used.

  Also, since large vehicles generally have a long service life, they are repainted at regular intervals to maintain and improve the appearance.

  Accordingly, for the coating of large vehicles, a coating composition capable of forming a cured coating film under mild drying conditions is used in both cases of new coating and recoating.

  Patent Documents 1 to 5 disclose an undercoat coating composition using a two-component urethane coating composition containing an acrylic polyol as a base resin and a polyisocyanate compound as a curing agent.

  Patent documents 1 to 5 have excellent adhesion to a substrate or a top coating film for repair by using the paint composition described as a paint for forming a substrate for automobile repair coating, and a coating film in which roughness is suppressed is obtained. As it is obtained, it is described that a repair coating having a natural appearance with less influence of the substrate can be obtained.

  However, when a paint composition that can be cured under these mild drying conditions is applied to the coating of a large vehicle, the paint after mixing of the two liquids solidifies in the middle of the coating because the time required for the coating becomes long. It may not be usable. In addition, since the painted area becomes wide, the finished skin also decreases. Particularly, there is a problem that the rough surface appears notably in the painted joint between the coating and the coating, and the overall finish is lacking.

  On the other hand, in Patent Document 6, a multilayer having an excellent appearance on a coated object such as a construction machine by applying different two-component urethane coating compositions having specific property values by wet-on-wet coating. It is stated that a coating can be provided.

  However, although the method described in Patent Document 6 is effective for omitting the coating time, it improves the rough surface which occurs in the application of the coating to be necessarily produced in the coating of the coated object over a wide area such as a large vehicle or construction machine. It has not been

Japanese Patent Application Laid-Open No. 2002-173632 Unexamined-Japanese-Patent No. 2014-047272 JP, 2015-096594, A JP, 2016-188284, A JP 2017-82197 A Patent No. 6177983 gazette

  An object of the present invention is to provide a primer coating composition suitable for forming a coating film having a good finish on the finish of a seam.

  The inventors of the present invention have found that it is important to control the viscosity of the paint mist to be applied to the coating portion when examining the surface roughness of the coating portion.

  FIG. 1 is an image view of a cross-sectional view of the splice portion, and FIG. 2 is a view of the splice portion viewed from above.

  As shown in FIG. 1, in the joint portion, the first-applied coated film and the second-applied coated film partially overlap. In the overlapping portion, the first coated film and the second coated film are both thinner than the surroundings, and although the same paint is applied, the completely different coating state from the surroundings It has become.

  Therefore, if the surface of the thin film portion of the first coated film is roughened at the joint portion, the film of the thin film applied thereon is directly affected by the lower layer. It is, of course, necessary to use a paint which is excellent in coating surface smoothness when it is applied to a thin film as well as a thick film.

  Then, it is also necessary that the paint mist applied to the boundary of the coated portion in the second coating becomes smooth and immediately conforms to the lower coat.

  In order to improve the smoothness of the coating film, a method of reducing the viscosity of the paint can be considered. However, simply lowering the viscosity of the paint does not necessarily improve the finished skin of the coated portion, and the storage stability of the paint tends to be further deteriorated.

  The present inventors diligently studied the above-mentioned problems. Then, by combining a silica fine particle in a specific amount with a paint composition containing an acrylic polyol and a polyisocyanate, an undercoat film can be obtained in which surface roughening of the applied portion is well suppressed during normal coating, thin film coating, and the like. I found out.

That is, the present invention
An organic solvent type multi-component primer coating composition obtained by mixing main component (I) and curing agent component (II),
The main component (I) contains an acrylic polyol (A1), a pigment composition (A2) and an organic solvent (A3),
The curing agent component (II) contains a polyisocyanate compound, and
The pigment composition (A2) contained in the main ingredient component (I) contains an extender pigment as a part of the component,
A primer coating composition, wherein the main component (I) and / or the curing agent component (II) contains 5 to 80 parts by mass of silica fine particles (A4) based on 100 parts by mass of the acrylic polyol (A1) non volatile matter, The present invention relates to a method for forming a primer coating film, which uses a coating composition for base coating, and a method for coating a large machine, which comprises the steps of coating the primer coating composition on a large machine and forming a primer coat.

  The primer composition of the present invention is excellent in storage stability for both the main agent and the curing agent, and the coating composition obtained by mixing the two is excellent in coating workability and can be sufficiently cured even under mild drying conditions.

  The primer coating composition of the present invention has a suitable pot life and can use the paint after mixing the two liquids for a long time, so it coats a substrate having a wide coating area such as a large machine such as a truck or a bath. Even if it is practical enough. In addition, it is possible to suppress a decrease in the finish skin of the seamed part, which occurs when the coated area is wide, and to form an undercoat film having a natural appearance that is entirely free from discomfort.

  Since the undercoat film formed by the method of the present invention has less overall surface roughness, it is possible to reduce or omit the number of man-hours required for the coating work by the paint manufacturer. Therefore, by using the undercoating composition of the present invention, the total work time required for forming the undercoating film for applying the topcoating to be applied thereon can be largely omitted.

  The primer coating composition of the present invention is a multicomponent composition obtained by mixing the main component (I) containing an acrylic polyol (A1) and the curing agent component (II) containing a polyisocyanate compound. Hereinafter, each component contained in this invention composition is demonstrated in order.

<Acryl polyol (A1)>
In the present invention, examples of the acrylic polyol (A1) include a hydroxyl group-containing copolymer of a polymerizable unsaturated monomer containing at least one (meth) acryloyl group-containing monomer.

  As the (meth) acryloyl group-containing monomer, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) Linear or branched alkyl (meth) acrylates such as acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate; cyclohexyl (meth) Alicyclic alkyl (meth) acrylates such as acrylate and isobornyl (meth) acrylate; aralkyl (meth) acrylates such as benzyl (meth) acrylate; 2-methoxyethyl (meth) acrylate, 2- Alkoxyalkyl (meth) acrylates such as xylethyl (meth) acrylate; hydroxy such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate Alkyl (meth) acrylate, hydroxyl group-containing (meth) acryloyl monomer such as polyoxyethylene chain-containing (meth) acrylate having a molecular terminal hydroxyl group; "Placcel FA-1", "Placcel FA-2", "Placcel FA-2D “,“ Placcel FA-3 ”,“ Placcel FA-4 ”,“ Placcel FA-5 ”,“ Placcel FM-1 ”,“ Placcel FM-2 ”,“ Placcel FM-2D ”,“ Placcel FM-3 ” , "Plaxel FM-4", " Lactone modified hydroxyalkyl (meth) acrylates such as "Laccel FM-5" (all manufactured by Daicel Chemical Co., Ltd., trade names); perfluoroalkyl (meth) acrylates; N such as N, N-diethylaminoethyl (meth) acrylate N-dialkylaminoalkyl (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, pentaerythritol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerol di (meth) acrylate, 1,1,1-trishydroxymethylethane di (meth) acrylate, 1,1,1- (Meth) acryloyl monomers having at least two polymerizable unsaturated groups in one molecule, such as trishydroxymethylethane tri (meth) acrylate, 1,1,1-trishydroxymethylpropane tri (meth) acrylate; ) Acrylic acid; Carbonyl group-containing (meth) acryloyl monomers such as acetoacetoxyethyl (meth) acrylate and diacetone (meth) acrylamide; Glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxy Epoxy group-containing (meth) acryloyl monomers such as chlorohexyl methyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, 3,4-epoxycyclohexylpropyl (meth) acrylate; isocyanatoethyl (meth) acrylate etc Isocyanato group-containing (meth) acryloyl monomers; alkoxysilyl group-containing (meth) acryloyl monomers such as γ-methacryloyloxypropyltrimethoxysilane and γ-methacryloyloxypropyltriethoxysilane; dicyclopentenyloxyethyl (meth) acrylate, di- And oxidation-curable group-containing (meth) acryloyl monomers such as cyclopentenyloxypropyl (meth) acrylate and dicyclopentenyl (meth) acrylate. Respectively alone or in combination of two or more can be used.

  Further, in the acrylic polyol (A1), other polymerizable unsaturated monomers other than the (meth) acryloyl group-containing monomer can also be used as a copolymerization component. As such other polymerizable unsaturated monomers, for example, (meth) acrylonitrile; vinyl ester compounds such as vinyl acetate and vinyl propionate; vinyl aromatic compounds such as styrene and α-methylstyrene; triallyl isocyanurate and diallyl terephthalate And polyvinyl compounds having at least two polymerizable unsaturated groups in one molecule such as divinyl benzene; carboxyl group-containing polymerizable unsaturated monomers such as maleic acid, crotonic acid, β-carboxyethyl acrylate and the like; allyl alcohol etc. (Meth) acrolein, formyl styrene, vinyl alkyl ketone having 4 to 7 carbon atoms (eg, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone, etc.), carbonyl group such as acetoacetoxy allyl ester Containing polymerizable unsaturated monomer; epoxy group containing polymerizable unsaturated monomer such as allyl glycidyl ether; isocyanato group containing polymerizable unsaturated monomer such as m-isopropenyl-α, α-dimethylbenzyl isocyanate; vinyltrimethoxysilane, vinyl Alkoxysilyl group-containing polymerizable unsaturated monomer such as triethoxysilane; epoxy-containing polymerizable unsaturated monomer or reaction product of hydroxyl group-containing polymerizable unsaturated monomer and unsaturated fatty acid, etc. Saturated monomer etc. are mentioned and these can be used individually or in combination of 2 or more types, respectively.

  The acrylic polyol (A1) has a weight average molecular weight of 5,000 to 80,000, preferably 6,000 to 70,000, and a hydroxyl value of 200 mg KOH / g or less, preferably 30 to 150 mg / KOH. Among them, the acid value is suitably in the range of 1 to 30 mg KOH / g, preferably 3 to 15 mg KOH / g. This is because the adhesion of the undercoating film is improved.

  In the present specification, the weight average molecular weight is a value obtained by converting the weight average molecular weight measured by a gel permeation chromatograph (manufactured by Tosoh Corp. "HLC 8120 GPC") with reference to the weight average molecular weight of polystyrene. The columns are “TSKgel G-4000H × L”, “TSKgel G-3000H × L”, “TSKgel G-2500H × L”, “TSKgel G-2000H × L” (all are manufactured by Tosoh Corp., trade names) Tetrahydrofuran, measurement temperature: 40 ° C., flow rate: 1 ml / min, detector; RI conditions were used.

  Further, as the above-mentioned acrylic polyol (A1), lactone-modified acrylic polyol is suitable from the viewpoint of adhesion of the undercoating film.

  Examples of the polymerizable unsaturated monomer used to lactone-modify the acrylic polyol include lactone-modified hydroxyalkyl (meth) acrylates as listed above, and the copolymerization ratio thereof is used for the production of the acrylic polyol. The amount is preferably in the range of 1 to 50% by mass, preferably 5 to 30% by mass, based on the total polymerizable unsaturated monomer used, from the viewpoint of the abrading property of the undercoating film to the topcoating film.

<Pigment composition (A2)>
In the present invention, the pigment composition (A2) contained in the main ingredient (I) contains an extender pigment.

  As the extender pigment, those known in the paint field can be used without limitation, for example, clays such as kaolinite, halloysite, pyroferrite or sericite; calcium carbonate, barium sulfate, barium carbonate, barium carbonate, aluminum silicate, gypsum, Examples thereof include talc, white carbon, diatomaceous earth, magnesium carbonate, alumina white, gloss white, mica powder and the like.

  The content of the extender pigment is suitably in the range of 50 to 500 parts by mass, preferably 100 to 400 parts by mass based on 100 parts by mass of the acrylic polyol (A1) non volatile matter contained in the main ingredient component (I) ing.

  In the present specification, the non-volatile content means a residue from which volatile components are removed, and the residue may be solid or liquid at normal temperature.

  It is suitable to include at least one selected from the group consisting of barium sulfate, talc, clay and calcium carbonate from the viewpoint of adhesion to the substrate and top coat as the extender pigment.

When the above is used as a part of the extender pigment, from the viewpoint of the adhesion of the undercoat film, etc., based on 100 parts by mass of the acrylic polyol (A1) nonvolatile matter,
The amount of barium sulfate is in the range of 30 to 250 parts by weight, in particular 50 to 200 parts by weight,
The amount of talc is 135 parts by mass or less, 100 parts by mass or less, particularly less than 50 parts by mass,
The amount of clay is adjusted in the range of 0.1 to 100 parts by weight, in particular 20 to 80 parts by weight, and the amount of calcium carbonate is adjusted in the range of 0.1 to 100 parts by weight, especially 20 to 80 parts by weight preferable.

  The pigment composition (A2) preferably contains a rust preventive pigment in addition to the extender pigment. This improves the water resistance and adhesion to the substrate of the primer coating formed from the primer composition of the present invention.

  Such anti-corrosive pigments include, for example, zinc compounds such as zinc and zinc oxide; magnesium phosphate, magnesium ammonium phosphate coprecipitate, magnesium monohydrogen phosphate, magnesium dihydrogen phosphate, magnesium calcium phosphate , Magnesium phosphate / cobalt co-precipitate, magnesium phosphate / nickel co-precipitate, magnesium phosphite, magnesium phosphite / calcium co-precipitate, calcium phosphate, calcium phosphite, ammonium phosphate, calcium monohydrogen phosphate, phosphorus Calcium dihydrogen phosphate, calcium phosphate fluoride, aluminum phosphate, aluminum hydrogen phosphate, aluminum tripolyphosphate, aluminum tripolyphosphate dihydrogen aluminum, magnesium tripolyphosphate, aluminum tripolyphosphate dihydrogen magnesium Treated metals, phosphate-based metal salts such as magnesium oxide-treated products of zinc tripolyphosphate; metal ion-exchanged silica; vanadium pentoxide, calcium vanadate, magnesium vanadate and ammonium metavanadate, manganese oxide and vanadium oxide Vanadium compounds such as calcined products, calcined products of calcium phosphate and vanadium oxide, and the like: Aluminum molybdate, calcium molybdate, aluminum phosphomolybdate, cobalt hydroxide and the like can be mentioned, and one or a combination of these can be used. Can be used.

  A zinc compound is suitable as the above-mentioned rust preventive pigment from the viewpoint of adhesion to the substrate.

  The preferable content of the rust preventive pigment is in the range of 1 to 100 parts by mass, preferably 5 to 50 parts by mass, based on 100 parts by mass of the acrylic polyol (A1) nonvolatile matter.

  In addition, the pigment composition (A2) may contain known pigments such as an extender pigment other than talc and a color pigment as needed.

  Examples of color pigments 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, condensed azo Yellow pigments such as yellow, azomethine yellow, bismuth vanadate, benzimidazolone, isoindolinone, isoindoline, quinophthalone, benzidine yellow, permanent yellow, etc. Orange pigments such as permanent orange, etc. Red iron oxide, naphthol AS azo red, ansanthrone , Red pigments such as anthraquinonil red, perylene maroon, quinacridone red pigment, diketopyrrolopyrrole, watching red, permanent red etc; cobalt purple, quinacridone violet, dioxadi Purple pigments such as violet; blue pigments such as cobalt blue, phthalocyanine blue, and slen blue; green pigments such as phthalocyanine green; metallic pigments such as aluminum powder, bronze powder, copper powder, tin powder, iron phosphide, etc .; metal oxide coating Examples thereof include pearlescent pigments such as mica powder and mica-like iron oxide, and these pigments can be used alone or in combination of two or more.

  From the viewpoint of finished appearance and the like, the preferred content of the color pigment is suitably in the range of 1 to 200 parts by mass, preferably 5 to 100 parts by mass, based on 100 parts by mass of the acrylic polyol (A1) non volatile matter. ing.

<Organic solvent (A3)>
Examples of the organic solvent (A3) in the present invention include organic compounds having a molecular weight of 58 to 220, particularly 72 to 200, and any known ones in the paint field can be used without limitation. For example, it is desirable to include at least one organic solvent selected from ester organic solvents and ketone organic solvents.

  As such an ester organic solvent, for example, 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 And diethylene glycol monoethyl ether acetate and the like, and examples of the ketone organic solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethyl isoamyl ketone, diisobutyyl ketone, methyl hexyl ketone, isophorone and the like. It can be used alone or in combination of two or more.

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

  In the present invention, the organic solvents other than the above 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 and the like; 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-dimethane Chill octane, 3,5-dimethyl octane, 4,4-dimethyl octane, 3-ethyl-3-methylheptane, 2-methylnonane, 3-methylnonane, 4-methylnonane, 5-methylnonane, 2-methylundecane, 3-methylundecane, 3-methylundecane Branched alkanes such as 2,2,4,6,6-pentamethylheptane; cyclopentane, t-decaline, 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 (C1) can be blended as a polymerization solvent or a dilution solvent in the production of the acrylic polyol (A1), or as a dilution in the production of the main ingredient (I).

<Silica fine particles (A4)>
The primer coating composition of the present invention contains silica fine particles (A4).

  By including the silica fine particles (A4), an effect is obtained that an undercoating film can be formed which is excellent in coating workability and excellent in appearance of the coated portion when coated on a coated object having a wide coated area. There is.

  Examples of the fine silica particles (A4) include silicon dioxide compounds such as hydrous silicon dioxide, natural crystalline silica, amorphous silica, anhydrous silica, fumed silica, colloidal silica, silica beads, etc. Two or more can be used in combination.

  As fine silica particles (A4), those having an oil absorption of 320 ml / 100 g or less, particularly 5 to 300 ml / 100 g, and an average particle diameter of 1.0 to 10.0, particularly 3.0 to 7.5 μm are used It is appropriate to do.

  In the present specification, the oil absorption amount is determined by measurement according to the oil method of boiled linseed according to JIS K 5101. Further, the average particle diameter can be determined by measuring the number average particle diameter using a laser diffraction / scattering method (for example, “Microtrack MT 3000” (manufactured by Microtrack Bell Inc.)).

  In the present invention, the fine silica particles (A4) may be contained in any of the main component (I) and / or the curing agent component (II), but it is suitably contained in the main component (I). The amount thereof is in the range of 5 to 80 parts by mass, preferably 20 to 40 parts by mass, based on 100 parts by mass of the acrylic polyol (A1) nonvolatile matter.

<Main agent component (I)>
As the main ingredient (I) constituting the undercoat composition of the present invention, in addition to the acrylic polyol (A1), the pigment composition (A2) and the organic solvent (A3), a viscosity modifier, a curing catalyst, cellulose acetate And additives for coating materials such as pigment dispersants, surface conditioners, resin particles, etc., as well as modifying resins other than acrylic polyols (A1) such as rate and its modified products, polyester resin, alkyd resin, polyurethane resin etc. .

  Among these, as a viscosity modifier, for example, an amide-based viscosity modifier, a polyethylene-based viscosity modifier, a layered viscosity mineral and the like can be mentioned. It is preferred to use a viscosity modifier.

  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 with formaldehyde, thermal condensation reaction of monocarboxylic acid with diamine, or dibasic acid with monoamine Fatty acid diamide (bisamide) synthesized by heat condensation reaction with; 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 Fatty acid polyamides obtained by the polycondensation of dimer acids, or the ring-opening polymerization of lactams.

  Such an amide-based viscosity modifier may be diluted with a dilution medium such as an organic solvent. In the present invention, the content of the active component (component other than the dilution medium) of the amide-based viscosity modifier is preferably 0.1 to 15 parts by mass, preferably 100 parts by mass of the non volatile matter of the acrylic polyol (A1). Is preferably in the range of 0.5 to 8 parts by mass.

  In particular, in the present invention, it is desirable to use the silica fine particles (A4) and an amide-based viscosity modifier in combination, from the viewpoint of the coating appearance and the storage stability of the splice portion. When both are used in combination, it is suitable that the ratio of the silica fine particles (A4) is high from the viewpoint of the coating film appearance of the spliced part as the combination ratio, and the total amount of the silica fine particles (A4) and the amide-based viscosity modifier It is suitable that the mass of the silica fine particles (A4) with respect to 100 parts by mass be in the range of 75 to 100 parts by mass, preferably 85 to 95 parts by mass.

  Moreover, as a curing catalyst, a conventionally known urethanization catalyst can be applied without particular limitation.

  Specific examples of the urethanization catalyst include dioctyltin dilaurate, dioctyltin dineodecanoate, dioctyltin bis (2-ethylhexyl maleate), dibutyltin dioctanoate, dibutyltin dilaurate, dibutyltin distearate, dioctyl Tin oxide or a condensate of dibutyltin oxide and silicate, dibutyltin diacetate, dibutyltin diacetylacetonate, dibutyltin bis (ethyl maleate), dibutyltin bis (butyl maleate), dibutyltin bis ( 2-ethylhexyl maleate), dibutyltin bis (oleyl maleate), stannas octoate, tin stearate, di-n-butyltin laurate oxide, dibutyltin bisisononyl 3-mercaptopropionate, dioctyl tin Bisisononyl 3-mercap Propionate, octylbutyltin bisisononyl-3-mercaptopropionate, dibutyltin bisisooctylthioglucolate, dioctyltin bisisooctylthioglucolate, octylbutyltin bisisooctylthioglucolate , Tin compounds such as tin dioctylate and tin distearate: calcium compounds such as calcium neodecanoate, calcium naphthenate and calcium octylate; triethylamine, tributylamine, dimethylbenzylamine, N-methylmorpholine, N-ethylmorpholine, N-cyclohexyl morpholine, N, N, N ', N'- tetramethylethylenediamine, N, N, N', N'- tetramethylbutanediamine or N, N, N ', N'- tetramethylhexanediamine, Pentamethyldiech N-triamine, bis (dimethylaminopropyl) urea, 1, 4-dimethylpiperazine, 1,2-dimethylimidazole, 1-azobicyclo [3.3.0] octane, 1,4-diazobicyclo [2.2.2] Octane, alkanolamine compounds, amine compounds such as triethanolamine, triisopropanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, dimethylethanolamine and the like; and the like can be mentioned.

  These can be used alone or in combination of two or more, but it is particularly suitable to use a tin compound and a calcium compound in combination from the viewpoint of the curability of the undercoat film and the viscosity increase inhibition after mixing with two liquids. .

  The curing catalyst may be contained in any of the main component (I) and the curing agent component (II), but when it is contained in the main component (I), the content of the curing catalyst is acrylic polyol (A1) Within the range of 0.01 to 10 parts by mass, preferably 0.1 to 5 parts by mass based on 100 parts by mass of the non-volatile content, the curability of the composition of the present invention and the main component (I) and the curing agent component (II) ) It is suitable from the viewpoint of suppression of viscosity rise after mixing.

  The main ingredient component (I) has a non-volatile content concentration in the storage state (sealed state) in the range of 60 to 85%, particularly 70 to 80%, and a thixotropic index of less than 4.50, particularly 1.00. It is suitable to be in the range of ~ 3.00.

  The storage stability is good when the nonvolatile matter concentration of the main agent component (I) and the thixotropic index are in this range, and the viscosity increase of the coating solution after mixing with the curing agent component (II) described later is moderate. Yes, and has excellent paintability. In addition, in the joint portion, there is an effect that the coated paint mist is well-adapted to the undercoat film as a base, and the undercoat film having an overall excellent appearance with no sense of incongruity with the surroundings can be obtained.

  In this specification, the thixotropic index of the main ingredient (I) adjusts the sample to 25 ° C., and the viscosity at a rotation speed of 6 rpm and 60 rpm with a single cylindrical rotation viscometer (B-type viscometer) It is the value which measured each and calculated ratio (viscosity at 6 rpm) / (viscosity at 60 rpm).

<Hardener component (II)>
In the present invention, the curing agent component (II) contains a polyisocyanate compound.

<Polyisocyanate compound>
The polyisocyanate compound is a polyisocyanate compound having two or more isocyanate groups in one molecule, and specific examples thereof include, for example, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, hydrogenated xyli Polyisocyanate compounds such as diisocyanate, xylylene diisocyanate, meta-tetramethyl xylylene diisocyanate, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, lysine diisocyanate, or these polyisocyanates and polyhydric alcohols, low molecular weight Examples include adducts with polyester resin or water, etc., or cyclized polymers of each polyisocyanate as described above, and further, isocyanate / biuret etc. , They may be used in combination of two or more kinds may be used in combination.

  The curing agent component (II) can optionally contain an additive for a paint such as an organic solvent; a viscosity control agent, a curing catalyst, a surface control agent and the like.

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

  The storage stability of each component is good, and the primer coating composition of the present invention has a good composition by comprising the primer composition as a multicomponent system of main component (I), curing agent component (II) and polyol component (III). Even if the step of forming the undercoating film by the composition and the step of coating the top-coating colored paint composition, which is the next step, are coated by wet on wet, or even if the polishing step is omitted or shortened, It is possible to form.

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

  An acrylic polyol is suitable as the above-mentioned polyol compound from the viewpoint of compatibility with the main component (I). The lactone-modified acrylic polyol may be used as the acrylic polyol contained in the polyol component (III).

  In the present invention, the polyol component (III) differs from the main component (I) in that the blending amount of the pigment is smaller than that of the main component (I). In the polyol component (III), the compounding amount of the pigment based on 100 parts by mass of the polyol compound nonvolatile content is suppressed to less than 20 parts by mass, preferably less than 0.5 parts by mass, or the pigment is substantially contained. Nothing is suitable from the perspective of the finished appearance in the wet on wet painting process.

  The concentration of the non-volatile component of the polyol component (III) is generally adjusted in the range of 10 to 70% by mass, preferably 20 to 60% by mass.

  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) is 30 based on 100 parts by mass of main agent component (I) It is suitable to be in the range of -150 parts by weight, preferably 50-120 parts by weight.

<Undercoat paint composition>
In the present invention, 0.5 to 3.0 equivalents of the isocyanate group in the curing agent component (II) are based on 1 equivalent of the hydroxyl group contained in the main ingredient (I) and the polyol component (III) used as needed. It is suitable to blend so that the ratio is preferably 0.7 to 2.5 equivalents. By setting the equivalent ratio of the hydroxyl group and the isocyanate group within this range, the viscosity increase after mixing the main ingredient (I) and the curing agent (II) is appropriately suppressed, and the undercoat paint excellent in coating workability It is because a composition is obtained.

  The composition of the present invention thus obtained is a two-component or three-component composition in which each component is stored separately, and generally, the components are mixed immediately before coating, and the viscosity is adjusted using a dilution thinner as necessary. Adjusted for use.

<Painting method>
The present invention further provides a coating method using the above primer coating composition for base coating.

  The substrate surface applicable to the method of the present invention is not particularly limited, and iron, aluminum, brass, copper, stainless steel, tinplate, galvanized steel, alloyed zinc (Zn-Al, Zn-Ni, Zn-Fe, etc.) ) Metal materials such as plated steel; polyethylene resin, polypropylene resin, acrylonitrile-butadiene-styrene (ABS) resin, polyamide resin, acrylic resin, vinylidene chloride resin, polycarbonate resin, polyurethane resin, resin such as epoxy resin, various FRPs, etc. Plastic materials; and painted surfaces coated on these.

  The coated material to which the method of the present invention is applied is not particularly limited, but it is necessary to apply the coating many times and it is necessary to obtain a cured coating film excellent in adhesion and abrasiveness without heating to high temperatures. For the reason, when applied to a large machine, the effects of the present invention can be maximized.

  Examples of the large-sized machine in the present specification include large-sized vehicles such as trucks, buses, fire trucks, dump trucks, container cars, trailers, tank lorries, and mixer cars; Shinkansen, trains, monorails, freight cars, electric locomotives, Rail vehicles such as diesel locomotives; construction machines such as tractors, road rollers, scrapers, forklifts, cranes etc .; aircrafts such as airplanes, gliders, helicopters etc.

  For the coating of the composition of the present invention, conventionally known coating methods can be employed, and spray coating is particularly preferred. As a coating film thickness, the inside of the range of 50-500 micrometers is mentioned by a dry average film thickness, and a thin film as well as a thick film coating is also possible.

  The primer coating composition of the present invention can cope with a wide range of drying conditions regardless of the season (summer / winter), humidity, presence or absence of drying equipment, and the like.

  In the case of natural drying, it can be left for 1 hour or more, particularly for 2 to 12 hours.

  On the other hand, forced drying can be performed for 5 to 120 minutes, particularly 10 to 90 minutes, at 40 to 80 ° C. using equipment such as a drying booth and a heater.

  Although natural drying or forced drying is preferable in the method of the present invention, it is also possible to carry out heat drying if necessary.

  When the method of the present invention is applied to the above-mentioned large-sized machine, any of new coating and re-coating may be used.

  For example, when repainting a large-sized machine that already has a coating, such as repainting a used large-sized vehicle, if necessary, apply primer coats to a large-sized machine to be coated. The putty may be shaped and then the primer coating composition of the present invention may be applied and overcoated thereon.

  In the top coating, conventionally known coatings such as 1-coat finish using only a top-coating color paint composition containing a metallic pigment and / or color pigment, or 2-coat finish using the color paint and clear paint Can be mentioned.

  As the top coat coloring paint composition, top coats of an organic solvent type, a water type or the like can be used without any particular limitation, and it can be coated by known coating means such as spray coating and electrostatic coating.

  In the case where the top-coating color coating composition is applied a plurality of times, if necessary, steps such as flash-off (after-coating coating is allowed to stand at normal temperature), air blow, preheating, etc. may be provided between each coating.

  There is no particular limitation on the drying after the application of the top coat color coating composition is finished, and it may be in the uncured state when the top clear is overcoated. In general, it is preferable to dry at, for example, 20 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 in general, the dry film thickness is suitably in the range of 5 to 100 μm, in particular 10 to 60 μm.

  As the top clear paint, a conventionally known one can be used without particular limitation, and for example, a curable paint containing an acrylic resin or fluorine resin as a main agent containing a crosslinkable functional group such as a hydroxyl group and a polyisocyanate as a curing agent Lacquers based on cellulose acetate butyrate-modified acrylic resin can be suitably used, and pigments, cellulose derivatives, additive resins, UV absorbers, light stabilizers, surface conditioners, and the like, if necessary. Paint additives such as curing catalysts can be included.

  Drying of the top clear paint is preferably carried out, for example, 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 in general, the dry film thickness is suitably in the range of 5 to 100 μm, in particular 10 to 60 μm.

  Hereinafter, the present invention will be more specifically described by way of examples. However, the present invention is not limited to only these examples. In the following examples, "parts" and "%" mean "parts by mass" and "% by mass", respectively.

<Production of two-component primer coating composition>
Example 1
7.5 parts of butyl acetate, 2 parts of methyl isobutyl ketone, 0.3 parts of a pigment dispersant, 8 parts of titanium white, 5.7 parts of talc, 30.5 parts of an acrylic resin solution (note 1) having a nonvolatile content of 55% 7.5 parts of clay, 24 parts of barium sulfate, 5.7 parts of silica (average particle diameter 6.7 μm, oil absorption 225, density 2.0), 5.7 parts of zinc oxide, 0.05 parts of dibutyltin dilaurate, 2 0.5 parts of calcium ethylhexanoate and 0.4 parts of an amide thickener (fatty acid amide, amide viscosity modifier) were sequentially mixed, mixed and stirred, and dispersed for 30 minutes to obtain a main ingredient . A coating composition for undercoating is mixed with 3.5 parts of a polyisocyanate compound ("Duranate TKA-100", trade name, NCO% manufactured by Asahi Kasei Co., Ltd .: 21.7%) as a curing agent to the main agent component immediately before use A-1) was obtained.

(Note 1) Acrylic resin solution (1)
Into a reaction vessel, 52 parts of butyl acetate is charged, and the temperature is raised to 110 ° C. while stirring, and 15 parts of styrene, 10 parts of methyl methacrylate, 10 parts of n-butyl methacrylate, 20 parts of t-butyl methacrylate, 2--2- methacrylate Monomer and polymerization initiator consisting of 19 parts of ethylhexyl, 15 parts of 2-hydroxyethyl methacrylate, Plaxcel FA-2D (trade name, product of Daicel Chemical Industries, reaction product of caprolactone and hydroxyethyl acrylate), 1 part of acrylic acid The monomer mixture was dropped at a constant rate over 3 hours using a dropping pump at 110.degree. C. or less. After completion of the dropwise addition, the temperature was maintained at 110 ° C. for 60 minutes and stirring was continued. Thereafter, as an additional catalyst, 0.5 parts of azobisisobutyronitrile dissolved in 7 parts of butyl acetate was dropped at a constant rate over 60 minutes. And after completion | finish of dripping, it kept 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 with a nonvolatile content of 55%, and the resin had a weight average molecular weight of 14000 and a hydroxyl value of 81 mg KOH / g.
(Note 2) Acrylic resin solution (2)
A reaction vessel is 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, 1 part of methacrylic acid, 2 A monomer mixture of a monomer consisting of 14 parts of hydroxyethyl methacrylate and 2.3 parts of azobisisobutyronitrile and a polymerization initiator was added dropwise at a constant rate over 3 hours using a dropping pump at 110 ° C. or less. After completion of the dropwise addition, the temperature was maintained at 110 ° C. for 60 minutes and stirring was continued. Thereafter, as an additional catalyst, 0.5 parts of azobisisobutyronitrile dissolved in 7 parts of butyl acetate was dropped at a constant rate over 60 minutes. And after completion | finish of dripping, it kept at 110 degreeC for 60 minutes, and reaction was complete | finished. The obtained hydroxyl group-containing acrylic resin solution had a nonvolatile content of 55% and was a uniform yellow transparent solution, and the resin had a weight average molecular weight of 18,000 and a hydroxyl value of 60 mg KOH / g.

Examples 2 to 11 and Comparative Examples 1 to 2
Coating compositions (A-2) to (A-11) and (A-13) to (A-) in the same manner as in Example 1 except that the composition shown in Table 1 is used in Example 1 above. 14) I got it.

<Production of Three-Component Primer Coating Composition>
Example 12
The main agent component, the curing agent component, and the clear composition (III) were mixed immediately before use according to the composition described in Table 1 to obtain a primer coating composition (A-12).

(Note 3) Clear composition (III)
40 parts of acrylic resin solution (1) (Note 1), 59.7 parts of butyl acetate, 0.2 parts of dibutyltin dilaurate, and 0.1 part of a surface conditioner are mixed in a stirring and mixing container, and are mixed by stirring to form a clear composition. I got a thing.

<Performance test>
(*) Thixotropic index value of main ingredient component The thixotropic index value of each main ingredient component used in the undercoat compositions (A-1) to (A-14) obtained in the above examples and comparative examples is described in the specification. It measured by the method of.
(*) Storage stability of main ingredient components Each main ingredient component used for undercoat coating compositions (A-1) to (A-14) obtained in the above Examples and Comparative Examples is enclosed in a 250 ml round can, 40 ° C. The contents were visually evaluated after 1 month storage.
◎: No change,
○: Slight pigment settling is confirmed, but it returns to the original by stirring,
Δ: There is pigment settling, and even if it is stirred, it does not return,
X: Significant pigment settling was observed and separated.

(*) Coating section Assuming a coating coating intended for large-sized machines with a coating area, a tin plate of 1000 × 1600 × 0.3 mm is the article to be coated, and each primer coating composition is drawn under the conditions of 35 ° C. Partially paint as shown in 3 and then paint the remaining portion to paint the first layer with the splice portion 1. After leaving it for 10 minutes or more at normal temperature, the second layer coating is divided into two steps so that a place different from the first layer becomes a coating joint as shown in FIG. 3 on the first undercoating film. It coat-painted and it was made to dry at 20 degreeC for 1 hour or more, and the evaluation paint board for the paint joint part nudge property was obtained. The painted surface of the central portion of the coated joints 1 and 2 of the test plate obtained was visually evaluated, and evaluated according to the following criteria.
:: The smoothness of the coated surface of the coated portions 1 and 2 is very good,
○: The smoothness of the coated surface of the coated portions 1 and 2 is good,
:: The painted surfaces of the coating portions 1 and 2 both stand out,
X: The paint mist does not conform to the coating portion 2 and dust is generated.

(*) Pot life Each paint composition obtained in the above Examples and Comparative Examples in which all the components are uniformly mixed is diluted by Iwata viscosity cup to be 11 to 15 seconds and left at 20 ° C. The time until was measured and evaluated by the following evaluation criteria.
◎: 120 minutes or more
○: 60 minutes or more and less than 120 minutes,
:: 30 minutes or more and less than 60 minutes,
X: less than 30 minutes.

(*) Put "LUC Polypate" (made by Kansai Paint Co., Ltd., unsaturated polyester putty) on a mild steel plate with a finished appearance of 300 x 100 x 0.8 mm with a spatula to a thickness of about 2 mm, 60 at 20 ° C After drying for a minute, the coated surface is ground with a P120 air-sharpened paper to smooth the surface, and the primer compositions obtained in the examples and comparative examples on the coated surface are used as a primer surfacer. It is prepared by dilution thinner so as to be 50% of non-volatile matter at the time of coating, and it is spray coated so that it has a dry film thickness of about 60 μm and then it is dried at 20 ° C for 60 minutes. The solvent-based metallic base paint was applied by air spray so as to have a dry film thickness of 15 μm. After coating, a commercially available organic solvent-type two-component urethane-curable coating was applied by air spray so as to have a dry film thickness of 40 μm on the uncured coating which was left at room temperature for 10 minutes. After leaving it for 10 minutes at room temperature, it was heated at 60 ° C. for 20 minutes using a hot air circulating drying oven to obtain a test plate. Then, the external appearance of each test paint board was observed from a squash direction (oblique direction), and the following evaluation criteria evaluated.
◎: The glossiness and the smoothness of the coated surface are very good, and neither suction nor plasaf marks are recognized,
○: Glossy feeling, coated surface smoothness is good, neither suction nor Prasaf marks are recognized, Δ: Glossy feeling, coated surface smoothness is slightly poor, neither suction nor Prasaff marks are recognized ,
X: Glossy feeling, coating surface smoothness is poor, and either suction or plasaf marks are observed.

(*) Adhesion Test A cross-cut test according to JIS K5600 was performed on the test coated plate obtained in the finished appearance test described above. Specifically, 100 cuts reaching the material in a grid pattern are made at intervals of 2 mm in the vertical and horizontal directions on the coating film, and an adhesive tape with an adhesive force (120 gf / 10 mm) is attached. And this adhesive tape was peeled off instantaneously, it peeled and the quantity of the coating film piece which adhered to the adhesive tape was investigated, and the following references | standards evaluated.
◎: no peeling between the primer coating and the metallic base coating,
○: Peeling number less than 5% between primer coating and metallic base coating,
:: Peeling number 5% or more and less than 10% between the primer coating and the metallic base coating
X: Peeling number 10% or more between the primer coating and the metallic base coating.

FIG. 1 is an image view of a cross-sectional view of a coating portion produced when a paint is applied to a substrate having a wide coating area. FIG. 2 is an image view from above of a coating portion produced when a paint is applied to an object to be coated having a wide area. FIG. 3 is a schematic view for explaining a test coating plate for evaluation of coating portion najimi property used in the embodiment of the present invention.

Claims (7)

An organic solvent type multi-component primer coating composition obtained by mixing main component (I) and curing agent component (II),
The main component (I) contains an acrylic polyol (A1), a pigment composition (A2) and an organic solvent (A3),
The curing agent component (II) contains a polyisocyanate compound, and
The pigment composition (A2) contained in the main ingredient component (I) contains an extender pigment as a part of the component,
An undercoat composition, wherein the main component (I) and / or the curing agent component (II) comprises fine silica particles (A4) in an amount of 5 to 80 parts by mass based on 100 parts by mass of the acrylic polyol (A1) non-volatile content. The primer composition according to claim 1, wherein the pigment composition (A2) further comprises a rust preventive pigment. The primer composition according to claim 1 or 2, further comprising an amide-based viscosity modifier. The primer composition according to any one of claims 1 to 3, further comprising a curing catalyst. The primer composition according to any one of claims 1 to 4, wherein the main component (I) has a thixotropic index of 4.0 or less.   A primer coating formation method using the primer coating composition according to any one of claims 1 to 5 for base coating. A method for coating a large-sized machine, comprising the steps of applying the primer coating composition according to any one of claims 1 to 5 to a large-sized machine to form a primer coating.

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