JP2002275414A - High solid content coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high solid content coating composition capable of forming a coating film excellent in a finished appearance, film hardness, resistance to acid rain, resistance to scratching, etc., and to provide a method for forming the coating film composed of plural layers by using the composition. SOLUTION: This high solid content coating composition contains a composition which comprises (A) a hydroxyl group-containing lactone-modified oligomer having a weight-average molecular weight of <=1,000 and a hydroxyl number of 200-800 in an amount of 5-30 wt.%, (B) a hydroxyl group-containing polymer having a weight-average molecular weight of 1,000-6,000 and a hydroxyl number of 50-200 in an amount of 5-50 wt.%, (C) a polyisocyanate compound in an amount of 30-70 wt.%, (D) a melamine resin in an amount of 3-30 wt.%, and (E) an alkoxysilyl group-containing compound in an amount of 1-30 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel high solids coating composition and a method for forming a multilayer coating film using the composition.

[0002]

2. Description of the Related Art In the field of paints, reducing the amount of organic solvents used has become an important issue from the viewpoints of environmental protection and resource saving against air pollution. As a countermeasure,
In organic solvent-based paints, there is a development of a so-called "high solid content paint composition" in which the amount of an organic solvent contained in the paint is reduced to increase the solid content concentration.

[0003] At present, most of the high solid content coating compositions which have been proposed are those in which a melamine resin is blended as a curing agent with a hydroxyl group-containing resin. However, when the viscosity is reduced by reducing the molecular weight in order to increase the solid content concentration in the coating material, there is a serious defect that the coating film performance is deteriorated. On the other hand, when a large number of crosslinkable functional groups such as hydroxyl groups are introduced in order to maintain the performance of the coating film in a low molecular weight state, the interaction between these functional groups increases the viscosity, which is not preferable. Then, it becomes difficult to reduce the viscosity.
In addition, when a large amount of melamine resin is blended, a large amount of by-products such as alcohol is generated during heat curing, so that the coating film has a defect that "blow" (foaming) is likely to occur.

[0004] Further, a top coat containing a melamine resin applied to an outer panel of an automobile used outdoors is liable to cause etching of the coating due to acid rain and stain-like stains, and also to cause scratches due to a car washing machine. It has a defect that it is easy to do. On the other hand, when a polyisocyanate compound is blended as a cross-linking agent, the viscosity of the melamine resin itself is lower than that of the melamine resin, so that high solidification is easily performed, and furthermore, acid rain resistance, car wash abrasion resistance and finish appearance (for example, Gloss, meat feeling, sharpness, etc.), but in the high concentration region where the solid content is 70% by weight or more,
There is a defect that the hardness of the cured coating film is not sufficient.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned deficiencies of the prior art, to reduce the viscosity of the paint and to show no decrease in the performance of the coating, and to further improve the finished appearance, the hardness of the coating, and the like. The present invention relates to a novel high solids coating composition which forms a coating film having excellent resistance to acid rain and scratches, and a method for forming a multilayer coating film using the composition. As a result of intensive studies, they have found that the purpose can be achieved by using a specific hydroxyl group-containing lactone-modified oligomer, a polyisocyanate compound, a melamine resin and an alkoxysilyl group-containing compound in combination, and further including a specific hydroxyl group-containing resin. The invention has been completed.

That is, according to the present invention, (A) the weight average molecular weight is 1000 or less, and the hydroxyl value is 200 to 80.
0-hydroxyl-containing lactone-modified oligomer: 5 to 30% by weight; (B) a hydroxyl-containing resin having a weight average molecular weight of 1,000 to 6000 and a hydroxyl value of 50 to 200: 5 to 50% by weight; (C) a polyisocyanate compound: 30 to 70% by weight, (D) melamine resin: 3 to 30% by weight and (E)
There is provided a high solids coating composition (hereinafter, referred to as "the present composition") comprising a composition comprising 1 to 30% by weight of an alkoxysilyl group-containing compound.

[0007] The present invention also relates to a colored coating film having one or more layers.
A multilayer coating film comprising at least one transparent coating film, wherein the uppermost transparent coating film is formed by the present composition (hereinafter, referred to as "the present method")
Is provided.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION First, the present composition will be described in detail.

The present composition is a high solids type coating composition, and preferably has a solids content of 70% by weight or more, especially 75 to 90% by weight, at the time of coating.

Component (A): a hydroxyl-containing lactone-modified oligomer having a weight average molecular weight of 1,000 or less and a hydroxyl value of 200 to 800.

The component (A) can be obtained, for example, by subjecting a polyvalent hydroxyl compound having two or more hydroxyl groups in one molecule to a lactone to a ring-opening esterification reaction.

The polyhydric hydroxyl compound is a compound having two or more hydroxyl groups in one molecule, for example, ethylene glycol, 1,2-propylene glycol, 1,2-butylene glycol, 2,3-butylene glycol. , 1,2
-Hexanediol, 1,2-dihydroxycyclohexane, pinacol, hydrolyzate of long-chain alkyl monoepoxide, aliphatic monoglyceride [for example, glycerin monoacetate (α-form), glycerin monostearate (α-form, etc.)], Α-glycols such as 3-ethoxypropane-1,2-diol and 3-phenoxypropane-1,2-diol; neopentyl glycol, 2-methyl-1,3-propanediol, 2-methyl- 2,4-
Pentanediol, 3-methyl-1,3-butanedio-
2-ethyl-1,3-hexanediol, 2,2-
Diethyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-butyl-2
-Ethyl-1,3-propanediol, 2-phenoxypropane-1,3-diol, 2-methyl-2-phenylpropane-1,3-diol, 1,3-propylene glycol, 1,3 -Butylene glycol, dimethylolpropionic acid, dimethylolbutanoic acid, 2-ethyl-1,3
-Octanediol, 1,3-didroxycyclohexane, aliphatic monoglyceride (for example, glycerin monoacetate (β-form) and glycerin stearate (β-form)
Β-glycol and the like.

Further, these α-glycols and β-glycols
Other than glycol, 1,4-butanediol, 1,4-
Dihydroxycyclohexane, 1,5-pentanediol, 1,6-hexanediol, 2,5-hexanediol, 3-methyl-1,5-pentanediol, 1,4
Dimethylolcyclohexane, tricyclodecanedimethanol, 2,2-dimethyl-3-hydroxypropyl-2,2-dimethyl-3-hydroxypropionate (which is composed of hydroxypivalic acid and neopentyl glyco- And bisphenol A, bisphenol F, bis (4-hydroxyhexyl)-
2,2-propane, bis (4-hydroxyhexyl) methane, 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, Diethylene glycol, triethylene glycol, tetra- or higher polyethylene glycol
, Copolymers having hydroxyl groups at both ends obtained by copolymerizing ethylene oxide and propylene oxide, linear polyesters having hydroxyl groups at both ends, carboxylic acid adducts of polycarbonate-todiol and diepoxide And the like can be applied as a polyvalent hydroxyl compound.

Further, glycerin, diglycerin, triglycerin, pentaerythritol, dipentaerythritol, sorbitol, mannitol, trimethylolethane, trimethylolpropane, ditrimethylolpropane, tris (2-hydroxy Ethyl) isocyanurate
G, gluconic acid, a polymer containing three or more hydroxyl groups
(For example, a polyester resin having three or more hydroxyl groups,
Polyether resins, acrylic resins, ketone resins, phenol resins, epoxy resins, urethane resins, natural sugars such as polyvinyl alcohol and glucose, which are saponified products of polyvinyl acetate resin, etc. Applicable as

Also, a hydroxyl-containing esterified product or polyester obtained by reacting these polyhydric hydroxyl compounds with a polybasic acid; a product obtained by subjecting an epoxy-containing compound or resin to a carboxyl-containing compound by an ester reaction; Oligomers such as products obtained by subjecting a hydroxyl group-containing compound to an ether reaction with a group-containing compound or a resin can also be used as the polyvalent hydroxyl group compound.

The lactones to be reacted with these polyhydric hydroxyl compounds are cyclic compounds having an ester group (—CO—O—) in the ring, and have 3 to 10, especially 4 to 7 ring members.
Is preferable, specifically, for example, β-propiolactone, γ-butyrolactone, δ-valerolactone, ε-caprolactone, enantholactone, 3-methyl-β-propiolactone, 3-methyl -Γ-butyrolactone, 3-methyl-δ-valerolactone, 3-methyl-ε-caprolactone, 4-methyl-ε-caprolactone, 3,3,5-trimethyl-ε-caprolactone and the like, particularly ε-caprolactone , 3-methyl-ε
-Caprolactone, 4-methyl-ε-caprolactone and the like are preferred.

The ring-opening esterification reaction between the polyhydric hydroxyl group compound and the lactone can be carried out by a known ring-opening esterification reaction. For example, the reaction temperature is 80 to 1
A temperature within the range of 80 ° C. is suitable, and a catalyst such as an organometallic compound such as tetraalkoxytitanium or an organotin compound, a Lewis acid, or a protonic acid can be used to promote this reaction. Is 0.005 per 100 parts by weight of the total of the polyhydric hydroxyl compound and the lactone.
~ 3 parts by weight are suitable.

The component (A) itself is already known and commercially available, for example, "TONE 0200"
Polyol "," TONE 0301 Polyo "
l "," TONE 0305 Polyol "(all of these are manufactured by Union Carbide, trade name)," Placcel 205 "," Placcel 303 "," Placcel 3 "
05 "(all of these are manufactured by Daicel Chemical Industries, trade name)
And so on.

The weight-average molecular weight of the hydroxyl-containing lactone-modified oligomer (A) is 1000.
Below, preferably 500-1000, hydroxyl value is 200
８００800, preferably 300-600. When the weight average molecular weight of the component (A) is larger than 1000, high solidification becomes difficult, and when the hydroxyl value is smaller than 200, the curability of the coating film becomes insufficient. None of them is preferred because the finished appearance and curability of the coating film are deteriorated due to poor compatibility with the above.

Component (B): a weight average molecular weight of 1,000 to
6000, a hydroxyl group-containing resin having a hydroxyl value of 50 to 200, and specifically, a polyester resin, an acrylic resin, and the like having a weight average molecular weight and a hydroxyl value within such ranges.

The hydroxyl group-containing polyester resin can be produced by subjecting a polybasic acid and a polyhydric alcohol to an esterification reaction under ordinary conditions.

The polybasic acid is a compound having two or more carboxyl groups in one molecule, for example, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, tetrahydrophthalic acid, Examples thereof include hexahydrophthalic acid, heptic acid, maleic acid, fumaric acid, itaconic acid, trimellitic acid, pyromellitic acid and anhydrides thereof.

The polyhydric alcohol is a compound having two or more hydroxyl groups in one molecule, for example, ethylene glycol
1,2-propylene glycol, 1,2-butylene glycol, 2,3-butylene glycol, 1,2-hexanediol, 1,2-dihydroxycyclohexane, 3-ethoxypropane-1, Α-glycols such as 2-diol and 3-phenoxypropane-1,2-diol; neopentyl glycol, 2-methyl-1,3-
Propanediol, 2-methyl-2,4-pentaneddiol, 3-methyl-1,3-butanediol, 2-ethyl-1,3-hexanediol, 2,2-diethyl-
1,3-propanediol, 2,2,4-trimethyl-
1,3-pentaneddiol, 2-butyl-2-ethyl-
1,3-propanediol, 2-phenoxypropane
1,3-diol, 2-methyl-2-phenylpropane-1,3-diol, 1,3-propylene glycol,
1,3-butylene glycol, 2-ethyl-1,3-octanediol, 1,3-didroxycyclohexane,
1,4-butanediol, 1,4-dihydroxycyclohexane, 1,5-pentanediol, 1,6-hexanediol, 2,5-hexanediol, 3-methyl-
1,5-pentanediole, 1,4-dimethylolcyclohexane, tricyclodecanedimethanol, 2,2-
Dimethyl-3-hydroxypropyl-2,2-dimethyl-3-hydroxypropionate (this is an esterified product of hydroxypivalic acid and neopentyl glycol), bisphenol A, bisphenol F, bis ( 4-hydroxyhexyl) -2,2-propane, bis (4-hydroxyhexyl) methane, 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,
4,8,10-tetraoxaspiro [5,5] undecane, diethylene glycol, triethylene glycol,
Glycerin, diglycerin, triglycerin, pentaerythritol, dipentaerythritol, sorbitol
Le, mannitol, trimethylol-ethane, trimethylo-
Lupropane, ditrimethylolpropane, tris (2-
(Hydroxyethyl) isocyanurate and the like.

The introduction of hydroxyl groups into the polyester resin can be carried out, for example, by using a polyhydric alcohol having three or more hydroxyl groups in one molecule.

The hydroxyl group-containing acrylic resin can be produced, for example, by copolymerizing a polymerizable monomer component containing a hydroxyl group-containing polymerizable monomer and an acrylic monomer by an ordinary method.

The hydroxyl group-containing polymerizable monomer is a compound having at least one hydroxyl group and at least one polymerizable unsaturated bond in one molecule, for example, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate -C2-C2 such as hydroxybutyl (meth) acrylate
Monoesters of glycol 20 and (meth) acrylic acid. The acrylic monomer is a monoester of (meth) acrylic acid and a monovalent alcohol having 1 to 22 carbon atoms, such as methyl acrylate, methyl methacrylate, ethyl acrylate, and ethyl acrylate. Methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, hexyl acrylate, hexyl methacrylate
Octyl acrylate, octyl methacrylate,
Lauryl acrylate, lauryl methacrylate, 2-
Ethylhexyl acrylate, 2-ethylhexyl methacrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate and the like can be mentioned.

In producing a hydroxyl group-containing acrylic resin,
Other polymerizable monomers other than these hydroxyl group-containing polymerizable monomers and acrylic monomers can be used in combination.

As other monomers, for example, methoxybutyl acrylate, methoxybutyl methacrylate,
(Meth) acrylic acid such as methoxyethyl acrylate and methoxyethyl methacrylate and an alkoxyester having 2 to 18 carbon atoms; N, N-dimethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate Ray
N, N-diethylaminoethyl acrylate, N, N
N-diethylaminoethyl methacrylate, Nt-butylaminoethyl acrylate, Nt-butylaminoethyl methacrylate, N, N-dimethylaminopropyl acrylate, N, N-dimethyl Aminoacrylic monomers such as aminopropyl methacrylate; acrylamide, methacrylamide, N-methylacrylamide,
Acrylamide-based monomers such as N-methylmethacrylamide, N-ethylacrylamide, N-ethylmethacrylamide, N-butylacrylamide, N-butylmethacrylamide, N-dimethylacrylamide, N-dimethylmethacrylamide; And glycidyl group-containing monomers such as glycidyl methacrylate;
Acrylic acid, methacrylic acid, maleic acid, itaconic acid,
Carboxyl group-containing polymerizable monomers such as fumaric acid, mesaconic acid and anhydrides and half esters thereof; styrene, α-methylstyrene, vinyltoluene, acrylonitrile, vinyl acetate, “Vova 9”, “Veoba” 10 "
(All manufactured by Yuka Shell Epoxy Co., Ltd., trade name), vinyl chloride and the like.

The weight average molecular weight of the component (B) represented by the polyester resin and the acrylic resin is 10
The hydroxyl value is within the range of from 00 to 6000, preferably from 2000 to 5200, the hydroxyl value is from 50 to 200, preferably from 80 to 150, and the acid value is not more than 15, especially from 4 to 10. When the weight average molecular weight of the component (B) is less than 1,000, the properties of the coating film deteriorate. When the weight average molecular weight is more than 6,000, high solidification becomes difficult. When the hydroxyl value is less than 50, the curability of the coating film deteriorates. If it is larger, the compatibility with other components is inferior, and the performance of the coating film is lowered based on the poor compatibility.

Component (C): Polyisocyanate compound The polyisocyanate compound is a compound having two or more free isocyanate groups (non-blocked) in one molecule, and a compound known per se is used. it can. For example, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, dimer acid diisocyanate,
Aliphatic polyisocyanate such as lysine diisocyanate
Alicyclic polyisocyanates such as hydrogenated xylylene diisocyanate, cyclohexylene diisocyanate, methylene bis (cyclohexyl isocyanate), and isophorone diisocyanate; tolylene diisocyanate Aromatic polyisocyanates such as phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate, and naphthalene diisocyanate : 2-isocyanatoethyl-2,6-diisocyanatocaproate, 3-isocyanatomethyl-1,6-
Trivalent or higher organic polyisocyanate compounds such as hexamethylene diisocyanate and 4-isocyanatomethyl-1,8-octamethylene diisocyanate (commonly called triaminononane triisocyanate); Dimer or trimer of a polyisocyanate compound having two or more isocyanate groups in one molecule; polyisocyanate having two or more isocyanate groups in one molecule
And urethanization reaction of the compound with a polyhydric alcohol, a low molecular weight polyester resin or water at an isocyanate group excess ratio, and the like.

In the component (C), a block polyisocyanate compound having an isocyanate group blocked can be used in combination with these non-blocked polyisocyanate compounds.

The block polyisocyanate compound is a compound obtained by blocking the isocyanate group of the above polyisocyanate compound with a blocking agent. As a blocking agent,
Examples include phenols, oximes, lactams, alcohols, mercaptans, active methylene compounds such as diethyl malonate, and the like. The ratio of these block polyisocyanate compounds is preferably not more than 50% by weight, particularly preferably not more than 30% by weight, based on the total amount of the non-blocked polyisocyanate compounds.

The weight average molecular weight of the component (C) is 2000
Hereinafter, the range of 200 to 1,000 is particularly preferable.

Component (D): Melamine resin.

It is used as a crosslinking agent together with the above-mentioned component (C), and includes a methylolated melamine resin obtained by reacting melamine with an aldehyde. Aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde and the like. Further, those obtained by etherifying this methylolated melamine resin with an appropriate alcohol can also be used. D
Examples of the alcohol used for tellurization include methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, and n-butyl alcohol.
, I-butyl alcohol, 2-ethylbutanol, 2
Monohydric alcohols having 1 to 10 carbon atoms, such as -ethylhexanol. The component (D) preferably has a weight average molecular weight in the range of 150 to 3000.

Component (E): an alkoxysilyl group-containing compound.

Compounds having one or more alkoxysilyl groups in one molecule are preferred, and the following compounds are preferred.

1) Dimethoxydimethylsilane, dimethoxydiethylsilane, dimethoxydiphenylsilane, diethoxydimethylsilane, trimethoxymethylsilane, trimethoxyethylsilane, trimethoxypropylsilane, trimethoxyphenylsilane, tetramethoxysilane, tetraethoxysilane, Non-functional alkoxysilane compounds such as tetrabutoxysilane and dimethoxydiethoxysilane, 2) γ-isocyanatopropyltrimethoxysilane,
γ-isocyanatopropylmethyldimethoxysilane,
silane coupling agents such as β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, 3) vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropylmethyldimethoxysilane, γ- ( (Meth) acryloyloxypropylmethyldiethoxysilane, γ
-An alkoxysilane compound having a polymerizable unsaturated group such as (meth) acryloyloxypropyltriethoxysilane, β- (meth) acryloyloxyethyltrimethoxysilane, and γ- (meth) acryloyloxybutylphenyldimethoxysilane; Nonfunctional alkoxysilane compound of 2), 2)
A siloxane bond-containing alkoxysilane compound obtained by partially condensing one or two or more kinds of alkoxysilyl group-containing compounds selected from the silane coupling agents of 3) and the polymerizable unsaturated group-containing alkoxysilane compounds of 3); Acrylic resins, polyester resins, alkyd resins, urethane resins, etc. modified with one or two or more selected from alkoxysilyl group-containing compounds of 4), 6) the polymerizable unsaturated group-containing alkoxysilane compounds of 3) above A polymer obtained by combining one or more kinds selected from the above and, if necessary, other polymerizable unsaturated monomers.

The component (E) has a weight average molecular weight of 1
It is preferably in the range of 50 to 50,000, particularly 500 to 10,000.

The composition of the present invention comprises (A) a hydroxyl-containing lactone-modified oligomer having a weight average molecular weight of 1,000 or less and a hydroxyl value of 200 to 800: 5 to 30% by weight, preferably 10 to 25% by weight; Weight average molecular weight of 1000
-6000, hydroxyl group-containing resin having a hydroxyl value of 50 to 200: 5 to 50% by weight, preferably 10 to 40% by weight,
(C) a polyisocyanate compound: 30 to 70% by weight,
Preferably 40 to 60% by weight, (D) melamine resin: 3
A composition comprising 30 to 30% by weight, preferably 7 to 25% by weight and (E) an alkoxysilyl group-containing compound: 1 to 30% by weight, preferably 3 to 15% by weight, is blended in an organic solvent and uniformly mixed. It can be prepared by mixing. These mixing ratios are based on the solid content ratio.

The composition of the present invention contains (A)
In addition to the components (B), (C), (D) and (E), it is also possible to further include (F) a curing catalyst and / or (G) a rheology control agent, if necessary.

Component (F): curing catalyst This is the component (A), component (B), (C),
It is useful for accelerating the crosslinking reaction of the coating film by the components (D) and (E). Specifically, tin octylate, dibutyltin di (2-ethylhexanoate), dioctyltin di (2-ethylhexanoate), dioctyltin diacetate, dibutyltin dilaurate, dibutyltin oxide, monobutyltin trioctate, Examples include organotin compounds such as lead 2-ethylhexanoate and zinc octylate. Further, acids such as paratoluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, butylphosphoric acid, octylphosphoric acid, and amine-neutralized products of these acids are preferred. (F) The amount of the curing catalyst used can be arbitrarily selected depending on the purpose of use, but (A), (B), (C), (D)
And 100 parts by weight of the total solid content of component (E)
005 to 3 parts by weight, particularly 0.01 to 3 parts by weight is suitable.

Component (G): rheology control agent By blending this component (G), the present composition can be imparted with thixotropic properties, whereby high shear can be obtained during spray coating such as spray coating or electrostatic coating. In the case where stress is applied, the viscosity is sufficiently reduced, and the spray coating operation can be easily performed.On the other hand, in the case where low shear stress is applied after coating on the surface to be coated, It is possible to increase the apparent viscosity. As a result, it is possible to prevent the occurrence of coating defects such as sagging and repelling when baking after painting on a vertical surface to be coated or upon baking after coating on the portion, and to form a coating film having a good finished appearance. The effect is obtained. Examples of such a rheology control agent include crosslinked polymer fine particles and polyurea compounds.

The crosslinked polymer fine particles can be obtained from the above (A)
(B), (C), (D) and (E) are little or no dissolution in the organic solvent and the like, and is an internally crosslinked particulate polymer that can be stably dispersed in the liquid composition of the present invention. .

As specific examples of the crosslinked polymer fine particles, there can be used an aqueous emulsion or a known intramolecularly crosslinked fine particle polymer obtained by an aqueous suspension polymerization method or a non-aqueous dispersion polymerization method. Among them, the aqueous emulsion or the finely divided polymer having an intramolecular crosslinked structure obtained by the aqueous suspension polymerization method is obtained by physical or chemical means such as evaporation or azeotropic distillation of water or precipitation or aggregation of the polymer (particles). , Can be separated in the form of a solid, or when physical or chemical means are applied, the medium of the target crosslinked polymer microparticles is replaced directly from water with another resin or organic solvent, etc. Can also.

As crosslinked polymer fine particles, JP-A-3-66
No. 770, a reactive emulsifier containing at least two radically polymerizable unsaturated groups in the molecule and another radically polymerizable unsaturated monomer in the molecule containing an allyl group. The crosslinked polymer fine particles obtained by emulsion polymerization in the presence of a polymer can be suitably used. In this case, the polymer fine particles are internally cross-linked by a polymerizable monomer having at least two unsaturated groups capable of radical polymerization in the molecule.

As the crosslinked polymer fine particles, poly (1
2-hydroxystearic acid) and a copolymer of a macromonomer (a) having an average of at least about one polymerizable unsaturated double bond per molecule and an ethylenically unsaturated monomer. And the solubility parameter (SP value) is 7.
5 to 9.2, and on average about 1.0 per molecule.
In the presence of a mixture with a macromonomer (b) having from about 1.5 to about 1.5 polymerizable unsaturated double bonds, each having at least two types of complementary functional groups capable of reacting and binding to each other. At least 0.5% by weight of vinyl monomer
The macromonomer (a), macromonomer (b) and the vinyl monomer are dissolved in the contained vinyl monomer mixture in an organic solvent in which the polymer of the vinyl monomer is substantially insoluble. And a dispersion liquid of gel polymer fine particles obtained by copolymerization and cross-linking reaction can be used. The crosslinked polymer fine particles themselves are known, and
This is disclosed in detail in Japanese Patent Publication No. 0110. The macromonomer (a) has a polymerizable unsaturated group-containing reaction product obtained by adding an epoxy group-containing polymerizable unsaturated unsaturated compound to a terminal carboxyl group of poly (12-hydroxystearic acid), and has an epoxy group. About one molecule per molecule obtained by adding a polymerizable unsaturated carboxylic acid to a pendant epoxy group-containing copolymer obtained by graft copolymerization or block copolymerization with a polymerizable unsaturated monomer mixture containing a polymerizable monomer. Macromonomers having from 1 to about 10 polymerizable unsaturated double bonds are preferred. In particular, the macromonomer (a)
Is preferably a macromonomer having one polymerizable unsaturated double bond in one molecule obtained by adding an epoxy group-containing polymerizable unsaturated unsaturated compound to a terminal carboxyl group of poly (12-hydroxystearic acid). It is. The macromonomer (b) preferably has a weight average molecular weight of 3,000 to 20,000 and a hydroxyl value of 45 to 150. The combination of complementary functional groups is, for example, an epoxy group / carboxyl group,
Alkoxysilyl group / hydroxyl group, epoxy group / phosphate group,
Examples include isocyanate groups / hydroxyl groups.

These crosslinkable polymer fine particles have a high crosslinking density and are substantially non-swellable and non-fusible even in an organic solvent having a high polymer dissolving power such as toluene or ethyl acetate. Moreover, when added to the present composition containing an organic solvent, the viscosity of the present composition hardly increases,
A solution (dispersion) having a high resin content, that is, a high solid content can be obtained. In the present composition containing the crosslinked polymer fine particles, both the fine particles and the binder resin form a cured coating film. The average particle diameter of the crosslinked polymer fine particles is 0.01
A range of about 2 to about 2 μm, particularly 0.05 to 0.5, is suitable. When the particle size is within this range, the sagging prevention effect of the coating film and the finished appearance of the coating film are excellent.

Further, a rheology control agent (G)
As a reaction product of a diisocyanate compound and benzylamine (see Japanese Patent Publication No. 60-23707).
Use of (a) or a polyurea compound in the form of solid particles comprising a reaction product of a polyisocyanate compound and an amine compound having one or more primary amino groups (see Japanese Patent Publication No. 7-81099) (b) Can be.

The reaction product (a) is obtained by reacting a diisocyanate compound with benzylamine. The diisocyanate compound is a compound having two isocyanate groups in one molecule and includes aliphatic, cycloaliphatic, and aromatic compounds.
It contains 40, preferably 4 to 20, carbon atoms, of which it is preferred to use symmetric aliphatic or cycloaliphatic diisocyanate compounds. Specifically, tetramethylene-1,4-diisocyanate, hexamethylene-1,6-diisocyanate, ω, ω′-
Dipropyl ether diisocyanate, thiodipropyl diisocyanate, cyclohexyl-1,4-diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, 1,5-dimethyl (2,4-ω-diisocyanatomethylbenzene), 1,5-dimethyl (2,
4-ω-diisocyanatoethylbenzene), 1,3,5
-Trimethyl (2,4-ω-diisocyanatomethylbenzene), 1,3,5-triethyl (2,4-ω-diisocyanatomethylbenzene), isophorone diisocyanate, dicyclohexyldimethylmethane-4,4′-diisocyanate 2,4-toluer diisocyanate,
2,6-toluene diisocyanate, diphenylmethane-4,4-diisocyanate and the like can be mentioned. Of these, hexamethylene-1,6-diisocyanate, toluene diisocyanate and the like are preferred.

In the reaction between the diisocyanate compound and benzylamine, it is preferable to use one of these two components in excess of the stoichiometric amount.
The ratio of the number of amino groups in benzylamine to the number of isocyanate groups in diisocyanate is preferably in the range of 0.7 to 1.5. The reaction between the two components is preferably performed, for example, in an inert gas atmosphere at a temperature of 10 to 150 ° C, particularly preferably 20 to 80 ° C. This reaction is preferably carried out in an inert solvent, for example, a solvent of an aliphatic hydrocarbon such as acetone, methyl ethyl ketone, benzene, toluene, xylene or petroleum ether. This reaction can also be carried out in the presence of the above components (A), (B), (C), (D) and (E).

The polyurea compound (b) in the form of solid particles is
It can be prepared by reacting a polyisocyanate compound with an amine compound having one or more primary amino groups.

The polyisocyanate compound is a compound having two or more isocyanate groups in one molecule, and includes monomers of the polyisocyanate compound and trimers of these isocyanurates.

As the monomer of the polyisocyanate compound, a polyisocyanate compound having 3 to 20, preferably 5 to 14, more preferably 8 to 12 carbon atoms, such as methylene diisocyanate, trimethylene diisocyanate, Methylene diisocyanate, hexamethylene diisocyanate, ω, ω ゜ dipropyl ether diisocyanate, thiodipropyl diisocyanate, cyclohexyl-1,4-diisocyanate, dicyclohexylmethane-4,4 ゜ -diisocyanate, 1,5-dimethyl-2,4-bis ( Isocyanatomethyl) -benzene, 1,5-dimethyl-2,4-bis (ω-isocyanatoethyl) -benzene, 1,3,5-
Trimethyl-2,4-bis (isocyanatomethyl) benzene, 1,3,5-triethyl-2,4-bis (isocyanatomethyl) benzene, a heterocycle sold under the trademark Desmodur TT of Bayer AG Examples thereof include diisocyanate, dicyclohexyldimethylmethane-4,4'-diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and diphenylmethane-4,4'-diisocyanate. If desired, heterocyclic trimers of two or three different diisocyanates may be used. Also, a mixture of the above heterocyclic triisocyanates can be used. Of these, hexamethylene diisocyanate is preferred. The isocyanurate trimerization of the monomer of these polyisocyanate compounds can be performed by a known method.

The secondary used to make the polyurea compound
Examples of suitable primary amines as components include benzylamine, ethylamine, n-propylamine, sec-
Propylamine, n-butylamine, sec-butylamine, tert-butylamine, n-pentylamine,
α-methylbutylamine, α-ethylpropylamine,
β-ethylbutylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine, aniline, hexamethylenediamine and the like. These primary amines generally contain up to 55 carbon atoms, preferably 1 to 24, more preferably 1 to 12 carbon atoms. Amines having one or more primary amino groups and one or more ether and / or hydroxyl groups can also be used, for example, ethanolamine, 6-aminohexanol, p-methoxybenzylamine, methoxypropylamine, , 4-dimethoxyphenylethylamine, 2,5-dimethoxyaniline, furfurylamine, tetrahydrofurfurylamine, bis (3-aminopropyl) polytetrahydrofuran (having a molecular weight of about 750).
Mixtures of the above amines can also be used.

In the reaction between the polyisocyanate compound and the primary amine for producing the polyurea compound, one of the polyisocyanate compound and the primary amine can be used in excess of the stoichiometric amount. For example, the ratio of the number of amino groups of the primary amine to the number of isocyanate groups of the polyisocyanate compound can be 0.7 to 1.5, preferably 0.9 to 1.1.

The reaction between the polyisocyanate compound and the primary amine can be generally carried out in any selected manner by mixing the reaction components and, if necessary, increasing the temperature. This reaction is preferably performed at a temperature of 10 ° C to 150 ° C, more preferably at a temperature of 20 ° C to 80 ° C. In general, the reactants can be mixed in any selected manner, but it is desirable to add the polyisocyanate compound to the primary amine, and it may be divided into several stages if necessary. Generally, the reaction is carried out in a solvent such as acetone, methyl isobutyl ketone, 1-methoxy-propanol-2,
It is performed in the presence of an aliphatic hydrocarbon such as benzene, toluene, xylene, or petroleum ether.

The amount of the component (G) can be arbitrarily selected depending on the purpose of use, but in terms of the solid content ratio, the components (A), (B), (C),
1 to 100 parts by weight of the total of components (D) and (E)
20 parts by weight, especially in the range of 2 to 10 parts by weight, are suitable.

The present composition comprises the above components (A), (B), (C), (D) and (E) as essential components, and further comprises (F) and (F) if necessary. Or)
(G) component can be included, in addition to this,
Furthermore, solid color pigments, metallic pigments, light interference pigments, extender pigments, ultraviolet absorbers, light stabilizers, anti-settling agents,
It is also possible to incorporate a coating surface adjuster and other paint additives, and the composition can be obtained by uniformly mixing these components with an organic solvent.

Examples of solid color pigments include quinacridone-based pigments such as quinacridone red; azo-based pigments such as pigment red; phthalocyanine-based organic pigments such as phthalocyanine blue, phthalocyanine green, and perylene red; and inorganic oxides such as titanium oxide and carbon black. Pigments; examples of metallic pigments include aluminum powder, vapor-deposited aluminum powder, aluminum oxide powder, nickel powder, copper powder, brass powder, and chromium powder; and interference color pigments include pearlescent pearls. Mica powder, pearlescent colored pearl mica powder and the like can be mentioned.

The present composition is used as an organic solvent type high solid content paint composition. Examples of the organic solvent include organic solvents for various paints, for example, aromatic or aliphatic hydrocarbon solvents, alcohol solvents, and ester solvents. Solvents, ketone solvents, ether solvents and the like can be used. The solid content concentration of the coating composition of the present invention at the time of coating is a high solid content of 70% by weight or more, preferably 75 to 90% by weight.

This composition contains (C) a polyisocyanate compound, which reacts relatively easily with the components (A) and (B) at room temperature. It is preferable to use the so-called two-pack type in which the components (A) and (B) are separated in advance. In the case of a two-pack type, each group may be mixed and used immediately before use. in this case,
The components other than the components (A), (B) and (C) are placed on either the component (A), the component (B) or the component (C) in consideration of the reactivity with the component (C). It is also possible to mix them or use them as the third component.

The present composition has a low viscosity so that it can be applied even when the solid content concentration at the time of application is 70% by weight or more. Therefore, the composition is easily applied by an airless spray, an air spray, a rotary atomization type coating method or the like. be able to. These coatings may be performed by applying static electricity. The present composition is excellent in atomization by these coating methods, and can form a coating film excellent in smoothness, sharpness, and feeling of holding.

The present composition is, for example, at 30 to 80 ° C.
Preferably, the coating can be performed after heating to 40 to 60 ° C. As the heating method, a composition (i) containing the components (A) and (B) and a composition (i) containing the component (C)
i) is heated and mixed, respectively, only the composition (i) is heated and then the composition (ii) is mixed, and only the composition (ii) is heated and then the composition (i). Mixing the
Heating after mixing the composition (i) and the composition (ii). This heating may further shorten the pot life of the present composition. Therefore, after heating, a two-liquid mixing device (for example, Precis, manufactured by GRACO)
It is possible to avoid the pot life problem by mixing uniformly using ion mix). For example, the composition (i) is charged into the A liquid tank and the composition (ii) is charged into the B liquid tank, and the A liquid tank is heated to 55 ° C. At that time, the liquid B tank is kept at room temperature. When the composition (i) and the composition (ii) are mixed using a two-liquid mixing device, the liquid temperature can be set to 40 ° C. In this case, the heating of the composition (i) and the composition (ii) may be performed in reverse. By heating in this manner, the viscosity of the present composition at the time of coating can be lowered, and as a result, the coatability of the present composition as a high solid content paint can be further improved.

The composition can be used as a solid paint, a metallic paint or an interference paint by blending various pigments such as a color pigment, a metallic pigment and an interference color pigment. In particular, the composition comprises
Since it is possible to form a cured coating film having excellent acid resistance, abrasion resistance, and finished appearance (for example, gloss, texture, and sharpness), at least one kind of colored paint and at least one
It is suitable to use the present composition as the uppermost clear paint in a method of forming a multilayer coating film by sequentially applying various clear paints.

Next, the present method, that is, a multi-layer coating film comprising one or more colored coating films and one or more transparent coating films, wherein the uppermost transparent coating film is formed by the present composition, The method for forming a multilayer coating film, which is characterized by the following, will be described.

In forming a multi-layer coating film by this method, the following method can be used as a method of using the present composition as the uppermost clear paint.

Method a: A coating method using the present composition as a clear paint in a two-coat system in which a colored paint and a clear paint are sequentially applied.

Method b: A coating method using the present composition as the second clear coating in a three-coat system in which a colored coating, a first clear coating, and a second clear coating are sequentially applied.

Method c: A coating method in which the present composition is used as a clear paint in a three-coat system in which a first colored paint, a second colored paint, and a clear paint are sequentially applied.

The methods a, b and c will be described in more detail.

In the above method a, the coloring paint may be
Solid color paints, metallic paints and interference color paints are included.

In the above colored paint, the resin component is, for example, an acrylic resin having a crosslinkable functional group (for example, a hydroxyl group, an epoxy group, a carboxyl group, an alkoxysilyl group, etc.), a vinyl resin, a polyester resin, an alkyd resin,
At least one kind of base resin such as urethane resin, and an alkyletherified melamine resin, urea resin, guanamine resin, cross-linked polyisocyanate compound, epoxy compound, carboxyl group-containing compound for crosslinking and curing the base resin And the like, and 50 to 90% of the base resin and 50 to 10% of the crosslinker component based on the total weight of both components.
It is preferable to use them together in a ratio of%. Pigments such as coloring pigments, metallic pigments, and interference color pigments, which are listed as known pigments that can be blended with the coating composition of the present invention, are blended with the coloring paint. These pigments can be used alone or in combination of two or more. Further, the coloring paint may be of an organic solvent type or an aqueous type.

In the method (a), a metal or plastic object to be coated, such as for an automobile, is applied directly, or an undercoat such as a cationic electrodeposition paint and, if necessary, an intermediate coat are applied.
After curing, the color paint is cured to a thickness of about 10 to 10 by a method such as airless spray, air spray, or rotary atomization (these may be electrostatically applied).
After coating so as to have a thickness of 50 μm, and curing by heating at about 100 to 180 ° C., preferably about 120 to 160 ° C. for about 10 to 40 minutes, or after leaving or preheating at room temperature for several minutes without curing. The clear paint of the present composition is cured to a film thickness of about 10 by the same coating method.
~ 70μm, about 100-180 ℃,
A two-coat, one-bake method (2C1B) or a two-coat, two-bake method (2C2B), which preferably comprises heating at about 120 to 160 ° C. for about 10 to 40 minutes for crosslinking and curing.
Can be performed.

In the method b, the same coloring paint as that described in the method a can be used as the coloring paint. The first clear coating is a coating for forming a transparent coating film, and a coating obtained by removing most or all of a pigment from a colored coating (the present coating composition may be used) can be used. Then, as the second clear paint, a clear paint composed of the present composition is used. Method b is a method a
In the same process as above, after applying and curing the colored paint,
Alternatively, after leaving or preheating at room temperature for several minutes without curing, the first clear paint is similarly applied on the colored coating by a coating method so that the film thickness becomes about 10 to 50 μm in the cured film thickness. 100-180 ° C, preferably about 120-
After heating and curing at 160 ° C for about 10 to 40 minutes,
Alternatively, after being left or preheated at room temperature for several minutes without curing, the second clear coating composition of the present composition is applied by a similar coating method so that the cured film thickness becomes about 10 to 50 μm. 100-180 ° C, preferably about 1
3 coats 1 bake method (3C1B) consisting of heating and curing at 20 to 160 ° C. for about 10 to 40 minutes, 3
It can be performed by a coat 2 bake method (3C2B) or a 3 coat 3 bake method (3C3B).

In the method c, as the first colored paint,
The same coloring paints as described in the section of the method a can be used. The second colored paint is applied on the painted surface of the first colored paint, and the color tone (solid color, metallic color, interference color) of the painted surface of the first colored paint can be visually recognized through the second colored paint film. A colored transparent paint having a small degree of hiding power is used. Therefore, the second
The hiding power of the colored coating film is usually smaller than that of the first colored coating film. A clear paint is applied on the second colored paint film. This clear paint is a paint for forming a transparent coating film, and the present composition is used. In method c, in the same process as method a, the first colored paint is applied and cured as a colored paint, or left or left at room temperature for a few minutes without curing before the first colored paint The second colored paint is applied so that the cured film thickness is about 10 to 50 μm, and is applied at about 100 to 180 ° C., preferably about 120 to 160 ° C.
After curing by heating at about 10 to 40 minutes at about 10 ° C., or after leaving or preheating at room temperature for several minutes without curing, the clear coating composed of the present composition is cured by a similar coating method. At about 100 to 180 ° C., preferably about 120 to 16 μm.
A three-coat, one-bake method (3C1B), a three-coat, two-bake method (3C2B) or a three-coat, three-bake method (3C) comprising heating and curing at 0 ° C. for about 10 to 40 minutes.
3B).

[0077]

The present invention relates to a so-called high solid content coating composition in which the amount of an organic solvent is reduced and the solid content is increased from the viewpoint of environmental protection and resource saving. In particular, the (A) hydroxyl-containing lactone-modified oligomer having a weight average molecular weight of 1,000 or less and a hydroxyl value of 200 to 800:
5 to 30% by weight, (B) weight average molecular weight of 1000 to 6
000 and a hydroxyl group-containing resin having a hydroxyl value of 50 to 200: 5 to 50% by weight, (C) a polyisocyanate compound: 30 to 70% by weight, and (D) a melamine resin: 3 to 30.
% By weight and (E) an alkoxysilyl group-containing compound: 1 to
The high solid content coating composition (the present composition) containing the composition consisting of 30% by weight enabled high solid differentiation without any deterioration in coating film performance. No waki (foaming) is generated on the coating film. Furthermore, as a top coating film for automobiles, it is possible to prevent etching of the coating film due to acid rain and occurrence of stain-like stains. This has the effect that almost no scratches are generated by the machine.

[0078]

EXAMPLES Examples and comparative examples according to the present invention will be described below. Parts and percentages are all by weight and the thickness of the coating is for the cured coating.

1. Preparation of Sample 1) (A) Component (A-1): Trimethylolpropane 40 was added to a reactor equipped with a stirrer, a cooler, a temperature controller and a nitrogen inlet tube.
0 parts, 100 parts of 2-butyl-2-ethyl-1,3-propanediol, 520 parts of ε-caprolactone and 0.2 part of dibutyltin dilaurate were charged, the atmosphere in the reaction vessel was replaced with nitrogen, and the mixture was stirred at 160 ° C. for 8 hours. By holding the mixture, a caprolactone-modified oligomer was obtained. It has a solids content of 93% and a Gardner viscosity (20
° C) XY, hydroxyl value: 560 mgKOH / g, number average molecular weight: 550, weight average molecular weight: 650.

2) Component (B) (B-1): 616 parts of ethyl-3-ethoxypropionate was placed in a reactor equipped with a stirrer, a cooler, a temperature controller, a nitrogen inlet tube and a dropping funnel. After charging, the inside of the reaction vessel was replaced with nitrogen, and heated to 150 ° C. In this, styrene 220 parts, isobutyl methacrylate 8
A mixture consisting of 80 parts, 242 parts of butyl acrylate, 330 parts of 2-ethylhexyl acrylate, 418 parts of 2-hydroxyethyl methacrylate, 88 parts of 2-hydroxyethyl acrylate, 22 parts of acrylic acid and 220 parts of azobisisobutyronitrile was charged for 5 hours. It dripped over. After dropping, the mixture was aged at 150 ° C. for 30 minutes to obtain an acrylic resin solution (B-1) having a solid content of 69% and Gardner viscosity (20 ° C.) PQ. The obtained acrylic resin (solid content) has a hydroxyl value of 100 mgKOH / g and an acid value of 7.2 m.
gKOH / g, number average molecular weight was 2050, and weight average molecular weight was 3070.

(B-2): A reactor equipped with a stirrer, a cooler, a temperature controller, a nitrogen inlet tube and a dropping funnel was charged with 616 parts of ethyl-3-ethoxypropionate.
The atmosphere in the reaction vessel was replaced with nitrogen, and the temperature was maintained at 150 ° C. by heating. Among them, 220 parts of styrene, 880 parts of isobutyl methacrylate, 330 parts of butyl acrylate,
A mixture consisting of 330 parts of ethylhexyl acrylate, 418 parts of 2-hydroxyethyl methacrylate, 22 parts of acrylic acid and 154 parts of azobisisobutyronitrile was added dropwise over 5 hours. After the completion of dropping, 30
Aged for 69 minutes, solid content 69%, Gardner viscosity (2
An acrylic resin solution (B-2) of 0 ° C.) T was obtained. The resulting acrylic resin (solid content) has a hydroxyl value of 82 mgKOH /
g, acid value 7.3 mgKOH / g, number average molecular weight 322
0, weight average molecular weight 5160.

(B-3): A reaction apparatus equipped with a stirrer, a cooler, a temperature controller, a nitrogen inlet tube and a dropping funnel was charged with 616 parts of ethyl-3-ethoxypropionate.
The atmosphere in the reaction vessel was replaced with nitrogen, and the temperature was maintained at 135 ° C. by heating. Among them, 220 parts of styrene, 880 parts of isobutyl methacrylate, 330 parts of butyl acrylate,
A mixture of 330 parts of ethylhexyl acrylate, 418 parts of 2-hydroxyethyl methacrylate, 22 parts of acrylic acid and 88 parts of azobisisobutyronitrile was added dropwise over 4 hours. After completion of the dropwise addition, the mixture was aged at 135 ° C. for 1 hour, and the solid content was 70% and the Gardner viscosity (20%)
C) Z acrylic resin solution (B-3) was obtained. The resulting acrylic resin (solid content) has a hydroxyl value of 82 mgKOH /
g, acid value 7.6 mgKOH / g, number average molecular weight 527
0, the weight average molecular weight was 10,800. (For comparison) 3) (G) component (G-1): A resin having an acid value of 30 and a number average molecular weight of about 1800, which is obtained by dehydrating and condensing 12-hydroxystearic acid under reflux of toluene with methanesulfonic acid as a catalyst. Glycidyl methacrylate was added to the terminal carboxyl group of the condensed polyester resin using dimethylaminoethanol as a catalyst to introduce a polymerizable double bond to obtain a macromonomer (a). It had a solids content of 70% and had about one polymerizable double bond based on the weight average molecular weight per molecule.

On the other hand, 174 parts of butyl acetate was placed in a flask and heated to reflux, and 70% of the macromonomer (a) was added thereto.
297 parts of a solution, 195.9 parts of methyl methacrylate, 18.5 parts of glycidyl methacrylate, 163.
A mixture consisting of 0 parts and 9.6 parts of 2,2-azobisisobutyronitrile was added dropwise at a uniform rate over 3 hours, followed by aging for 2 hours. Then, a mixture of 0.05 parts of pt-butylcatechol, 3.8 parts of methacrylic acid, and 0.5 part of dimethylaminoethanol was added to the flask, and the mixture was heated at 140 ° C. until the resin acid value reached 0.5. The reaction was carried out for 5 hours to obtain a macromonomer (b) having a solid content of 50%. The obtained macromonomer (b) is a graft polymer having a first segment made of poly 12-hydroxystearic acid and a second segment made of a copolymer of methyl methacrylate and glycidyl methacrylate. It had an average of four polymerizable unsaturated double bonds.

On the other hand, 153 parts of xylene were placed in a flask and heated to 125 ° C., and then 50 parts of 2-ethylhexyl acrylate, 23 parts of n-butyl acrylate, 25 parts of 2-hydroxyethyl acrylate, 2 parts of acrylic acid, t
A mixture of 4.5 parts of butyl peroctoate in 4 parts
The mixture was dropped over a period of time, and then aged for 2 hours. The obtained acrylic resin varnish had a solid content of 65% and a number average molecular weight of 7,000. This acrylic resin varnish 1
To 00 parts, 2 parts of glycidyl methacrylate, 0.01 part of 4-t-butylpyrocatechol, and 0.15 part of tetrabutylammonium bromide were added, and the mixture was stirred at 115 ° C. for 7 hours to introduce a copolymerized double bond into the molecule. As a result, a macromonomer (c) was obtained. The number of introduced double bonds in the macromonomer (c) is about 1.0 based on the weight average molecular weight per molecule.
The SP value is 8.70 and the hydroxyl value is 121 mgKOH
/ G.

A flask was charged with heptane 190, 20 parts of a 50% macromonomer (b) solution and 23 parts of a 65% macromonomer (c) solution, and at reflux temperature, 20 parts of a 50% macromonomer (b) solution, 65% 23 parts of macromonomer (c) solution, 50 parts of methyl methacrylate, 2-
50 parts of hydroxyethyl acrylate, 1.5 parts of glycidyl methacrylate, 0.8 part of methacrylic acid, 2,2
A mixture consisting of 2 parts of '-azobisisobutyronitrile was added dropwise over 5 hours, followed by aging for 2 hours. Then
0.1 part of dimethylaminoethanol was added, and the mixture was aged for 4 hours to obtain a non-aqueous dispersion of polymer fine particles. The obtained dispersion was a white dispersion having a solid content of 40%, and the particle diameter was about 160 nm (peak particle diameter). The particle diameter was measured using a "COULTER N4 submicron particle analyzer" manufactured by Coal Tar. The particles were insoluble in organic solvents such as acetone, ethyl acetate and xylene.

2. Examples and Comparative Examples The above components were used and mixed at the ratios shown in Table 1 to obtain high solids type coatings. The amounts of the components (A) to (G) are all solids ratios. The solid content is at the time of painting. These were subjected to the following performance tests. Table 2 shows the results.

[0087]

[Table 1]

(Note 1) "TONE0301 Polyol": trade name, lactone-modified oligomer manufactured by Union Carbide. Weight average molecular weight 700, hydroxyl value about 561 mg KO
H / g.

(Note 2) "Death module N3300":
An isocyanurate type of hexamethylene diisocyanate, manufactured by Sumitomo Bayer Urethane Co., Ltd.

(Note 3) “LT1”: trade name, 2-isocyanatoethyl-2,6-diisocyanatocaproate, manufactured by Kyowa Hakko Co., Ltd. Weight average molecular weight about 267.

(Note 4) "Cymel 325": trade name, imino-type melamine resin, manufactured by Mitsui Cyanamid Co., Ltd.

(Note 5) “Cymel 303”: trade name, manufactured by Mitsui Cyanamid Co., Ltd., a completely alkyl melamine resin.

(Note 6) Alkoxysilyl group-containing compound:
Alkoxysilyl group-containing vinyl monomer ("KBM50
3 "(trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) and a polymerizable monomer component containing hydroxyethyl methacrylate, and has a weight average molecular weight of 3,000 and a hydroxyl value of 82 mgKOH / g.

(Note 7) “N5543”: a trade name, a solution of an amine neutralized dodecylbenzenesulfonic acid, manufactured by King Industries, USA.

(Note 8) "Scat 24": trade name, tin catalyst, manufactured by Sankyoki Gosei Co., Ltd.

(Note 9) "Setalux C-7176VB-60": trade name, rheology modifier manufactured by Akzo. Polyurea compound. Non-aqueous dispersion.

[0097]

[Table 2]

(Note 10) Finishability: The appearance of the coated surface of the test coated plate was visually determined. ○ is good in smoothness, gloss and sharpness and no abnormality is recognized, △ is slightly inferior in smoothness, gloss and sharpness, × is one in smoothness, gloss and sharpness Significantly worse.

(Note 11) Hardness: means the two-cone hardness (20 ° C.) of the multilayer coating film of the test coated plate.

(Note 12) Scratch resistance: Polishing sand (Dalmac cleanser) was kneaded with water on the coated surface of the test coated plate, and was placed on the coated surface with a test machine terminal and a load of 0.5 kg was applied. After 25 reciprocations, evaluation was made visually. ◎ indicates that no change in gloss or the like was observed on the coated surface, ○ indicates that slight change was observed in the gloss of the coated surface, △ indicates that slight gloss was observed, and x indicates that gloss was significantly observed.

(Note 13) Acid resistance: 0.4 cc of a 30% sulfuric acid aqueous solution was dropped in spots on the surface of the multilayer coating film of the test plate.
Heat in a hot air dryer at 60 ° C for 15 minutes, then wash with water,
The coated surface was visually evaluated. ◎ indicates no change on the painted surface, ○ indicates very few spot marks on the painted surface, △
Indicates that spot marks are slightly observed, and X indicates that spots, whitening or blisters are remarkably observed in the spot marks.

Continued on the front page (72) Inventor Naoshi Isaka 4-171-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa F-term (reference) in Kansai Paint Co., Ltd. 4J038 CG001 CG002 DA162 DD001 DD002 DD111 DG262 DG302 DL022 DL032 GA03 JB24 JC13 JC20 JC39 KA03 MA14 MA15 NA01 NA03 NA04 NA11

Claims (3)

[Claims] (A) a hydroxyl-containing lactone-modified oligomer having a weight average molecular weight of 1,000 or less and a hydroxyl value of 200 to 800: 5 to 30% by weight; (B) a weight average molecular weight of 1,000 to 6000 and a hydroxyl value of 50 to 200 hydroxyl group-containing resin: 5 to 50% by weight, (C) polyisocyanate compound: 30 to 70% by weight, (D) melamine resin:
A high solids coating composition comprising a composition comprising 3 to 30% by weight and (E) 1 to 30% by weight of an alkoxysilyl group-containing compound. 2. The composition according to claim 1, further comprising (F) a curing catalyst and / or (G).
2. The method according to claim 1, further comprising a rheology control agent.
A high solids coating composition as described in the above. 3. A high solids coating composition according to claim 1 or 2, which is a multilayer coating comprising at least one colored coating and at least one transparent coating, wherein the uppermost transparent coating is a multilayer coating. A method for forming a multilayer coating film, comprising: