JPH08269165A - Low-solvent type resin composition, coating composition made from the same and its coating and baking method - Google Patents

Abstract

PURPOSE: To obtain a low-solvent type resin composition suitable as an intermediate coating for automobile body, bumper, etc., a solid color coating, a clear coating, a base coating, etc., especially giving a coating film having excellent resistances to acid, gasoline, water, weather and chipping, and capable of remarkably reducing the amount of organic solvent to be used in the coating material. CONSTITUTION: This coating composition contains a coating binder consisting of (1) an oligomer (resin) containing 1.5-5.0mol/kg-resin of hydroxyl group and/or blocked hydroxyl group and having a number-average molecular weight of 700-3,000 and a weight-average molecular weight of 700-6,000 and (2) a compound containing plural cycloaliphatic epoxy groups in one molecule and having a molecular weight of 230-800. The molar ratio of the oligomer/cycloaliphatic epoxy group compound is 1/(0.7-20) and the content of the organic solvent in the coating composition is 5-40wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an intermediate coating suitable for coating automobile bodies, bumpers, etc.
The present invention relates to a low solvent type coating composition which can be suitably used as a solid color coating material, a clear coating material, a base coat and the like. In particular, the present invention can form a coating film excellent in chipping resistance, acid resistance, water resistance, gasoline resistance, weather resistance, and further thick film property, and can significantly reduce the amount of organic solvent used. The present invention relates to a low solvent type resin composition, a low solvent type coating composition using the same as a binder, and a suitable coating method for the low solvent type coating composition.

[0002]

2. Description of the Related Art Generally, in an organic solvent type paint, an organic solvent used in the organic solvent type paint is volatilized and released into the atmosphere during a coating process such as a baking process, which is a cause of deteriorating the global environment. ing. In recent years, intermediate coatings or top coatings for automobile outer panels and the like have been coated with a combination of polyester polyol and melamine resin, and a large amount of organic solvent is exhausted to the atmosphere from this coating line. When this exhausted organic solvent is burnt, a large amount of carbon dioxide is generated, accelerating the global warming phenomenon. Therefore, various attempts have hitherto been made to reduce the amount of organic solvent used. For example, in order to reduce the amount of organic solvent, a high solid content coating composition in which a polyester polyol is blended with a low molecular weight melamine resin, and an acrylic high solid content coating composition have been proposed (for example, Japanese Patent Laid-Open Publication No. Sho. 61-
9461 and JP-A-55-123660). However, with these coating compositions, it is difficult to reduce the amount of organic solvent to, for example, 40% or less, and the degree of reduction of the amount of organic solvent is insufficient from the viewpoint of environmental protection. Further, in a system in which a low molecular weight melamine resin is blended with a polyol, there is a problem that water stains and etching are caused by acid rain. In addition, there has been a problem such that the sagging on the vertical surface is remarkable due to the decrease in viscosity when coating the paint.

On the other hand, for the purpose of reducing the amount of organic solvent, a water-based paint that does not use or substantially does not use an organic solvent,
Although powder coatings and the like have been widely studied, water-based coatings have poor water resistance, and the amount of organic solvent is still required to be about 20%. Further, in powder coating, since it is necessary to use a resin having an extremely high glass transition temperature, the coating tends to be brittle, and the requirements for scratch resistance and chipping resistance required for top coating and intermediate coating are satisfied. There was a problem such as not being able to do it. Therefore, there has been a strong demand for a coating composition capable of further significantly reducing the amount of organic solvent while improving coating properties such as acid resistance, chipping resistance, water resistance, gasoline resistance, weather resistance, and thick film property. .

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a low solvent type resin composition having good coating properties and capable of greatly reducing the amount of organic solvent used, and the low solvent type resin composition as a binder. Low solvent type coating composition to be used,
Furthermore, it aims at providing the coating method suitable for coating the low solvent type coating composition. Means for Solving the Problems The present inventors have conducted extensive studies to achieve the above object, and as a result, as a coating binder, (1) a specific vinyl-polymerized oligomer having a hydroxyl group or a blocked hydroxyl group, a resin such as a polyester oligomer (hereinafter, simply , "Oligomer") and (2) an alicyclic epoxy group-containing compound having an alicyclic epoxy group in one molecule and having a molecular weight of 230 to 800, thereby effectively achieving the above object. The present invention has been accomplished and the present invention has been achieved. That is, the present invention is: (1) It contains hydroxyl groups and / or blocked hydroxyl groups of 1.5 to 5.0 mol / kg resin and has a number average molecular weight of 700 to 3
And an alicyclic epoxy group-containing compound containing a plurality of alicyclic epoxy groups in one molecule and having a molecular weight of 230 to 800, and an oligomer having a weight average molecular weight of 700 to 6000. Contains the above-mentioned oligomer /
The alicyclic epoxy group compound has a molar ratio of 1 / 0.7 to 1 /
1. The low solvent type resin composition, wherein the amount is 20 and the amount of the organic solvent is 5 to 40%. (1) It contains hydroxyl groups and / or blocked hydroxyl groups of 1.5 to 5.0 mol / kg resin and has a number average molecular weight of 700 to 3
And an alicyclic epoxy group-containing compound having a weight average molecular weight of 700 to 6000 and (2) a plurality of alicyclic epoxy groups in one molecule and a molecular weight of 230 to 800, ( 3) a cationic polymerization catalyst,
A low solvent type coating composition, characterized in that the molar ratio of the oligomer / the alicyclic epoxy group compound is 1 / 0.7 to 1/20, and the amount of the organic solvent is 5 to 40%. Things, 3. 3. A coating method, which comprises coating the surface of an article to be coated with the low-solvent type coating composition described in 2 above, and then thermally curing the composition to form a coating film on the surface of the article to be coated; A method for coating the surface of an article to be coated with the low-solvent type coating composition according to 2 above, which extends in the usual vertical direction on the surface of the article to be rotatably supported about a substantially horizontal axis. On the surface, the coating material is applied to a film thickness that causes sagging, then, before the sagging of the coating material applied to the surface of the coating object is caused by gravity, the coating object starts to rotate around a substantially horizontal axis, and Rotation is at least such a speed that the surface of the coating object shifts from a substantially vertical state to a substantially horizontal state before the sagging of the applied paint is caused by gravity, and at a speed slower than the speed at which the sagging of the paint is caused by the centrifugal force due to the rotation. The present invention relates to a coating method characterized by rotating.

The present invention will be described in detail below. The oligomer containing a hydroxyl group or a blocked hydroxyl group used in the present invention has a hydroxyl group amount or a blocked hydroxyl group of 1.5
~ 5.0 mol / kg resin, number average molecular weight is 700 ~
3,000, and the weight average molecular weight is 700 to 6000.
Is. When the amount of hydroxyl groups or blocked hydroxyl groups is less than 1.5 mol / kg resin, crosslinking becomes insufficient and properties such as gasoline resistance are deteriorated. On the other hand, when the amount of the hydroxyl group or the blocked hydroxyl group is more than 5.0 mol / kg resin, the viscosity becomes too high and it becomes difficult to produce the low solvent type resin composition of the present invention. The amount of hydroxyl groups or blocked hydroxyl groups is preferably 2 to 4 mol / kg resin. When the number average molecular weight of the oligomer is less than 700, the amount of functional groups introduced into one molecule is less than 2,
Crosslinking becomes insufficient, and gasoline resistance and the like decrease. On the other hand, when the number average molecular weight is more than 3000,
Viscosity increases. The preferred number average molecular weight is 800 to 2
500, and particularly preferably 350 to 1100. The weight average molecular weight of the oligomer is 700 to 600 for the same reason as in the case of the number average molecular weight.
0, and the preferable weight average molecular weight is 800 to 500.
0.

The weight average molecular weight / number average molecular weight of the oligomer used in the present invention is preferably 1.0 to 2.0.
And particularly preferably 1.0 to 1.7. If the weight average molecular weight / number average molecular weight ratio is greater than 2.0,
Since too many oligomers having too large a molecular weight and oligomers having too small a molecular weight are contained in a relatively large amount, problems arise when the molecular weight is too large or too small. On the other hand, the lower limit is theoretically 1.0, and an oligomer having uniform properties can be obtained. And, the smaller the molecular weight of the oligomer is within the scope of the present invention, the closer it can be to this theoretical value. The hydroxyl group of the oligomer is
---- A functional group represented by OH. On the other hand, the blocked hydroxyl group is a functional group obtained by blocking the above hydroxyl group with a blocking group derived from a blocking agent, and the blocked hydroxyl group represented by the following structure is preferred. --OZ (1) Here, Z is a blocking group derived from the blocking agent bonded to the hydroxyl group. As Z, a block group represented by the following formula can be mentioned as a preferable example. [1] Silyl Block Group As the silyl block group, a silyl block group represented by the following formula (2) can be exemplified.

[0007]

Embedded image R ^{1 to} R ³ in the above formula (2) are an alkyl group or an aryl group. The alkyl group includes a linear or branched alkyl group having 1 to 10 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a s-butyl group,
t-butyl group, pentyl group, hexyl group, etc., with 1 carbon atom
Particularly preferred are ~ 8 lower alkyl groups. The aryl group includes a phenyl group which may have a substituent, a naphthyl group, an indenyl group and the like, and a phenyl group is particularly preferable. As the silyl block group represented by the formula (2),
Trimethylsilyl group, diethylmethylsilyl group, ethyldimethylsilyl group, butyldimethylsilyl group, butylmethylethylsilyl group, dimethylphenylsilyl group, methylethylphenylsilyl group, diethylphenylsilyl group, diphenylmethylsilyl group, diphenylethylsilyl group, etc. Is mentioned. In particular, the smaller the molecular weight of R ^{1 to} R ^3, the smaller the volatile components, which is preferable for reducing the amount of organic solvent. As a blocking agent for forming such a silyl block group, halogenated silane can be preferably used. The halogen atom contained in the halogenated silane is preferably a chlorine atom or a bromine atom. Specific blocking agents include, for example, trimethylsilyl chloride, diethylmethylsilyl chloride, ethyldimethylsilyl chloride, dimethylphenylsilyl chloride, methylethylphenylsilyl chloride, diphenylmethylsilyl chloride and the like, and further dimethylbutylsilyl bromide and methyl. Examples thereof include ethylbutylsilyl bromide and methylbutylphenylsilyl bromide. [2] Vinyl ether block group As the vinyl ether block group, a vinyl ether block group represented by the following formula (3) is exemplified.

[0008]

Embedded image R ¹ , R ² and R ³ in the above formula (3) are each a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms. R ⁴ is a hydrocarbon group having 1 to 18 carbon atoms, and R ³ and R ⁴ may be bonded to each other to form a heterocycle having Y as a hetero atom. Y is an oxygen atom or a sulfur atom. Formula (3) above
Examples of the hydrocarbon group therein include an alkyl group, a cycloalkyl group, an aryl group and the like. As the alkyl group, for example, a lower alkyl group having 1 to 8 carbon atoms such as methyl group, ethyl group, propyl group, butyl group, s-butyl group, t-butyl group, pentyl group and hexyl group is particularly preferable. . Examples of the cycloalkyl group include a cyclopentyl group and a cyclohexyl group. The aryl group includes a phenyl group which may have a substituent, a naphthyl group, an anthracene group and the like, and a phenyl group is particularly preferable. Such vinyl ether blocking groups can be formed by reacting an aliphatic vinyl ether or thioether or a cyclic vinyl ether or thioether with a hydroxyl group. Examples of the aliphatic vinyl ether include methyl vinyl ether, ethyl vinyl ether, isopropyl vinyl ether, n-propyl vinyl ether, isobutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether and the like, or a vinyl thioether corresponding thereto. Examples of the cyclic vinyl ether include 2,3-dihydrofuran, 3,4-dihydrofuran, 2,3-dihydro-2H-pyran, 3,4-dihydro-2H-pyran and 3,4-dihydro-2-methoxy. -2H-pyran,
3,4-dihydro-4,4-dimethyl-2H-pyran-
2-one, 3,4-dihydro-2-ethoxy-2H-pyran, 3,4-dihydro-2H-pyran-2-carboxylic acid sodium and the like can be mentioned.

Of the above-mentioned block groups, a silyl block group is preferable because it can lower the viscosity and improve the sagging resistance.
As the oligomer (or resin) used in the present invention,
Oligomers such as vinyl polymerized oligomers and polyester oligomers can be used without limitation. The hydroxyl group-containing vinyl-polymerized oligomer can be produced by copolymerizing a vinyl-polymerizable monomer having a hydroxyl group, alone or, if necessary, with any other vinyl-polymerizable monomer. On the other hand, the blocked hydroxyl-containing vinyl polymerized oligomer is a vinyl-polymerized monomer containing a blocked hydroxyl group, which is used alone or as a copolymer with any other vinyl-polymerizable monomer as necessary, or the hydroxyl-containing vinyl polymerized above. It can also be produced by blocking the oligomer with the above blocking agent. As the hydroxyl group-containing vinyl polymerizable monomer, a vinyl polymerizable monomer having a hydroxyl group and a radical polymerizable unsaturated bond group can be mentioned as a preferable monomer. Examples of the radical-polymerizable unsaturated bond group include a radical-polymerizable vinyl bond represented by CHR ¹ = CR ^2- (wherein R ¹ and R ² are each a hydrogen atom, an alkyl group or a single bond). It can be preferably mentioned. Here, the alkyl group includes an alkyl group having a straight chain or a branched chain,
Examples thereof include a methyl group, an alkyl group having 1 to 20 carbon atoms such as an ethyl group, a propyl group, and a butyl group.

Examples of the hydroxyl group-containing vinyl polymerizable monomer having such a hydroxyl group and a radical polymerizable unsaturated bond group include monomers represented by the following formula (4).

[0011]

Embedded image In the formula, R ¹ is a hydrogen atom or a methyl group, R ² is a divalent alkylene group, and Y is —COO—, —CO—, —O—, —N.
HCO- or a single bond. In particular, a hydroxyl group-containing acrylic oligomer in which Y is a -COO- bond is preferable. As the divalent alkylene group, for example, a linear or branched alkylene group having 1 to 18 carbon atoms, for example, a methylene group, an ethylene group, a propylene group,
Examples thereof include butylene group, hexylene group, heptylene group, octylene group, nonylene group, decylene group, undecylene group, dodecylene group and tridecylene group. Examples of the hydroxyl group-containing vinyl polymerizable monomer represented by the above formula include 2-hydroxyethyl (meth) acrylate and 2
-Or 3-hydroxypropyl (meth) acrylate,
2-, 3- or 4-butyl (meth) acrylate etc. are mentioned. Furthermore, as the hydroxyl group-containing vinyl polymerizable monomer, a hydroxyl group-containing vinyl polymerizable monomer obtained by modifying the monomer represented by the above formula with a lactone can also be used. As such a hydroxyl group-containing vinyl polymerizable monomer, for example, a monomer represented by the following formula (5) can be mentioned.

[0012]

[Chemical 4] Here, R ¹ , R ² and Y are as described above. n is 2
7, preferably 2-5, m is 1-10, preferably 2-8. Specific examples of the lactone-modified vinyl polymerizable monomer (lactone adduct) represented by the above formula (5) include Praxel FM-1 and FM-2 manufactured by Daicel Chemical Industries, Ltd.
Examples thereof include FM-3, FM-4, FM-5, FA-1, FA-2, FA-3, FA-4 and FA-5. Here, FM is a methacrylate-based lactone-modified hydroxyl-containing vinyl-polymerizable monomer, and FA is an acrylate-based lactone-modified hydroxyl-containing vinyl-polymerizable monomer. Also, the numbers are the amount of lactone added. For example, FA-1 is an acrylate-based hydroxyl group-containing vinyl polymerizable monomer to which one lactone molecule is added. Examples of such a lactone-modified hydroxyl group-containing vinyl polymerizable monomer include a methacrylic monomer represented by the following formula (6).

[0013]

Embedded image In the formula, n is 2 to 7 and m is 1 to 10. For example, Praxel FM-1, FM-2, FM-3, and FM-4 are monomers corresponding to this formula, and specifically have a structure represented by the following formula.

[0014]

[Chemical 6]

[0015]

[Chemical 7] The hydroxyl group-containing vinyl polymerizable oligomer can be prepared directly or indirectly by copolymerizing the hydroxyl group-containing vinyl polymerizable monomer alone or with another copolymerizable monomer. The vinyl polymerized oligomer can be prepared, for example, as follows. Method 1: A method in which a vinyl-polymerizable monomer having a short hydroxyl group position from a vinyl group is polymerized once (along with other vinyl-polymerizable monomers as necessary) and then reacted with a lactone. Method 2: A vinyl polymerizable monomer containing a carboxyl group is reacted with an epoxy group-containing compound, and then a vinyl polymerizable monomer containing a secondary hydroxyl group produced by the reaction between a carboxyl group and an epoxy group is prepared. A method of polymerizing the above with other vinyl polymerizable monomers, and a method of adding a lactone to the obtained hydroxyl group-containing vinyl polymerized oligomer to prepare a vinyl polymerized oligomer.

The carboxyl group-containing vinyl polymerizable monomer used here is, for example, a compound in which the hydroxyl group is a carboxyl group in the above formula (4), for example,
(Meth) acrylic acid etc. can be mentioned. As the epoxy group-containing compound, for example, a compound having an epoxy group having no vinyl-polymerizable unsaturated group can be used without particular limitation. For example, epoxides of aliphatic hydrocarbons having unsaturated bonds, especially α
-Epoxide of olefin, glycidyl ether,
Glycidyl ester and the like can be preferably used. As the epoxide of the α-olefin epoxide, an epoxide having 3 to 25 carbon atoms is preferable. For example, propylene oxide, AOEX24 (epoxide mixture of α-olefin having 12 and 14 carbon atoms) and AOEX68 (epoxide mixture of α-olefin having 16 and 18 carbon atoms) (above, manufactured by Daicel Chemical Industries)
And the like. Examples of the glycidyl ether include butyl glycidyl ether, phenyl glycidyl ether, decyl glycidyl ether, cresyl glycidyl ether, and the like. Further, examples of glycidyl ester include Khajura E10 and PES.
10 (above, epoxy group resin made by Yuka Shell) can be mentioned. Method 3: generated by reacting a vinyl polymerizable monomer containing an epoxy group with a compound containing a carboxyl group
A method in which a vinyl-polymerizable monomer containing a primary hydroxyl group is polymerized with another vinyl-polymerizable monomer as necessary, and a method in which a lactone is added to the obtained hydroxyl-containing vinyl-polymerized oligomer to prepare the same.

Here, as the vinyl-polymerizable monomer having an epoxy group, the monomer having a hydroxyl group as an epoxy group in the above (4) can be preferably used. Examples of such an epoxy group-containing vinyl polymerizable monomer include glycidyl (meth) acrylate. Further, as the compound containing a carboxyl group, various compounds can be used without particular limitation as long as they are compounds containing a carboxyl group having no vinyl-polymerizable unsaturated group. Examples of such compounds include, for example, fatty acids such as capric acid and caprylic acid,
A half ester obtained by reacting an alcohol with an acid anhydride such as phthalic anhydride or succinic anhydride can be preferably used. Here, as the alcohol, an alcohol having one hydroxyl group or a polyol having a plurality of hydroxyl groups can be used. Examples of the alcohol having one hydroxyl group include methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol and the like. Examples of the polyol include ethylene glycol, propylene glycol, 1,
5-hexanediol, 1,6-hexanediol, neopentyl glycol, cyclohexanedimethanol and other diols, trimethylolpropane, trimethylolethane, trihydric alcohols such as glycerin, pentaerythritol, diglycerin and other 4 Examples include hydric alcohols. Method 4: A method in which a vinyl-polymerizable monomer containing a carboxyl group or an epoxy group is polymerized with another vinyl-polymerizable monomer, if necessary, and then a compound containing an epoxy group or a carboxyl group is reacted, and the resulting hydroxyl group. A method for preparing a vinyl polymerized oligomer by adding a lactone to a vinyl polymerized oligomer containing vinyl. Method 5: A vinyl polymerizable monomer containing an epoxy group is reacted with a reaction product of a polyol, a lactone, an acid anhydride or a dibasic acid, and the obtained vinyl polymerizable monomer containing a hydroxyl group is added, if necessary. A method for preparing a vinyl polymerized oligomer by polymerizing with other vinyl polymerizable monomer.

As the polyol, the above-mentioned polyol can be used. Examples of the acid anhydride include phthalic anhydride, alkyl phthalic anhydride such as 4-methylphthalic anhydride, hexahydrophthalic anhydride, and 3-hydrophthalic anhydride.
Examples thereof include alkylhexahydrophthalic anhydride such as methylhexahydrophthalic anhydride and 4-methylhexahydrophthalic anhydride, succinic anhydride, and tetrahydrophthalic anhydride. In particular, it is preferable to use alkyl phthalic anhydride or alkylhexahydrophthalic anhydride because of the ease of synthesis. Examples of the dibasic acid include alkylphthalic acid such as phthalic acid and 4-methylphthalic acid, alkylhexahydrophthalic acid such as hexahydrophthalic acid, 3-methylhexahydrophthalic acid and 4-methylhexahydrophthalic acid,
Examples thereof include succinic acid and tetrahydrophthalic acid. Method 6: A vinyl-polymerizable monomer containing an epoxy group is polymerized with another vinyl-polymerizable monomer, if necessary, to produce an epoxy-group-containing vinyl polymerized oligomer, and then a polyol, a lactone, or an acid anhydride. , A method of reacting a dibasic acid to prepare a vinyl polymerized oligomer. Method 7: A hydroxyl group-containing vinyl polymerizable monomer obtained by reacting a polyester polyol obtained by reacting a polyol with a lactone, and a vinyl polymerizable monomer containing an isocyanate group, together with other vinyl polymerizable monomers, if necessary. A method for preparing a vinyl polymerized oligomer containing a hydroxyl group by polymerizing.

Here, as the isocyanate group-containing vinyl polymerizable monomer, those in which the hydroxyl group in the above formula (4) is an isocyanate group can be used. Specific examples include isocyanate ethyl (meth) acrylate. Method 8: Isocyanate group-containing vinyl polymerizable monomer is polymerized together with other vinyl polymerizable monomer as necessary, and the obtained isocyanate group-containing vinyl polymerized oligomer is reacted with a polyol or a compound in which a lactone is added to a polyol. And a method for preparing a vinyl polymerized oligomer. In addition to the above methods, various applications are conceivable, but the range is obvious to those skilled in the art. Examples of the blocked hydroxyl group-containing vinyl polymerizable monomer used for producing the blocked hydroxyl group-containing vinyl polymerizable oligomer include vinyl polymerizable monomers in which the hydroxyl group is the blocked hydroxyl group (--OZ) in the above formula (4), A vinyl polymerizable monomer obtained by blocking the lactone-modified hydroxyl group-containing vinyl polymerizable monomer can be preferably used. The blocked hydroxyl-containing vinyl-polymerizable oligomer can be obtained by copolymerizing the above-mentioned blocked hydroxyl-containing vinyl-polymerizable monomer alone or with another copolymerizable vinyl-polymerizable monomer. It can also be produced by blocking the hydroxyl group-containing vinyl polymerized oligomer produced as described above.

The vinyl polymerizable monomer can be polymerized by a known conventional means. For example, the polymerization can be performed by anionic polymerization, ionic polymerization such as cationic polymerization, or radical polymerization. In the present invention, radical polymerization is preferred from the viewpoint of ease of polymerization. However, in the case of producing a vinyl polymerized oligomer having a low molecular weight, a mercaptan such as mercaptoethanol, thioglycerol, lauryl mercaptan or a chain transfer agent is used in the polymerization so that the vinyl polymerized oligomer having a low molecular weight can be produced. Method, 60 ~
It is desirable to adopt a method of reacting at 180 ° C., a method of reacting at a low monomer concentration, or the like. Also,
The molecular structure of the vinyl polymerized oligomer is not particularly limited,
For example, various structures such as a linear shape, a comb shape, a block shape, a star shape, and a star burst shape can be used. Radical polymerization is preferably performed in solution. As the solvent used for such radical solution polymerization,
Any solvent conventionally used for polymerizing vinyl-polymerizable monomers such as acrylic monomers can be used without limitation. Examples of such a solvent include toluene, xylene, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, Solvesso (manufactured by Exxon) and the like.

As the radical reaction initiator used in radical solution polymerization, a reaction initiator conventionally used in radical polymerization can be used without limitation. Examples of such a reaction initiator include peroxides such as benzoyl peroxide, lauroyl peroxide, t-butyl hydroperoxide, t-butyl peroxy-2-ethylhexanol, azobis valeronitrile, and azobis. Examples thereof include azo compounds such as isobutyronitrile and azobis (2-methylpropionitrile). In the production of the hydroxyl group- or blocked hydroxyl group-containing vinyl polymerized oligomer used in the present invention, another polymerizable monomer that can be optionally used together with the hydroxyl group- or blocked hydroxyl group-containing vinyl polymerizable monomer, for example, α, Examples of the β-ethylenically unsaturated monomer include the following monomers. (1) Acrylic acid or methacrylic acid ester: For example,
Methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, methacrylic acid Alkyl groups having 1 to 18 carbon atoms of acrylic acid or methacrylic acid such as butyl, hexyl methacrylate, octyl methacrylate, and lauryl methacrylate;
Methoxybutyl acrylate, methoxybutyl methacrylate, methoxyethyl acrylate, methoxyethyl methacrylate, ethoxybutyl acrylate, ethoxybutyl methacrylate, etc. Acrylic acid or methacrylic acid ester having 2 to 18 carbon atoms; alkoxyalkyl ester; allyl Acrylic acid or methacrylic acid alkenyl ester such as acrylate or allyl methacrylate having 2 to 8 carbon atoms; Acrylic acid or methacrylic acid alkenyloxy such as allyloxyethyl acrylate or allyloxyethyl methacrylate having 3 to 18 carbon atoms Alkyl ester. (2) Vinyl compounds: for example, vinyl acetate, hexafluoropropylene, tetrafluoropropylene, styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene. (3) Polyolefin compound: For example, butadiene,
Isoprene, chloroprene. (4) Allyl ethers: hydroxyethyl allyl ether and the like. (5) Others: For example, methacrylamide, acrylamide, diacrylamide, dimethacrylamide, acrylonitrile, methacrylonitrile, methyl isopropenyl ketoin, vinyl acetate, vinyl propionate, vinyl pivalate, acrylic acid, methacrylic acid, N, N. -Dialkylaminoalkyl (meth) acrylate, perfluorovinyl ether such as trifluoromethyl vinyl ether, vinyl ether such as hydroxyethyl vinyl ether and hydroxybutyl vinyl ether.

The proportion of the hydroxyl group- or blocked hydroxyl group-containing monomer unit (main chain monomer unit having a hydroxyl group- or blocked hydroxyl group-containing graft moiety) in the vinyl polymerized oligomer containing a hydroxyl group or a blocked hydroxyl group is preferably: It is 50 to 100%, particularly preferably 70 to 100%. When the content of the hydroxyl group or the blocked hydroxyl group-containing monomer unit is less than 50%,
When the glass transition temperature is low, the hardness is not obtained, which is not preferable. On the other hand, the polyester oligomer used in the present invention is an oligomer having a hydroxyl group or a blocked hydroxyl group and an ester bond in the molecule. Examples of preferable polyester oligomers include star type or star burst type polyester oligomers. Here, the star type means that when a polyhydric alcohol or a polyhydric epoxy compound is used as a starting material, these functional groups at the end of the extension portion radially extended from the center (virtual center) of the molecule. In addition, an acid anhydride, a monoepoxy compound, or a lactone or a monocarboxylic acid having a hydroxyl group reacts with each other to further extend the radial extension and have a star shape. What is the starburst type?
From the middle of the extension that extends radially from the center like this,
It has a branched shape. When a hydroxyl group- or blocked hydroxyl group-containing polyester oligomer having such a shape is used, the viscosity of the oligomer becomes low and the coating film obtained becomes tough. The length of the radially extending portion can be freely adjusted by the molar ratio at the time of reaction and the structure of the reactant.

The star type or star burst type hydroxyl group- or blocked hydroxyl group-containing polyester oligomer which can be preferably used in the present invention can be produced, for example, by the following method. Method 1 For a polyol having 3 to 6 hydroxyl groups in one molecule, 1
By sequentially reacting an acid anhydride having one acid anhydride group in the molecule, a lactone and a monoepoxy compound having one epoxy group in the molecule in various combinations, a star type hydroxyl group-containing polyester oligomer is obtained. It is formed. Further, by using a monoepoxy compound having a hydroxyl group instead of the monoepoxy compound, it is possible to produce a starburst type hydroxyl group-containing polyester oligomer in which a branch is formed at the terminal of a radial extension. Specifically, the following modes are possible. (1) In 1 mol of a polyol having 3 to 6 hydroxyl groups,
0.3-1.5 moles of acid anhydride are reacted, then 2-10
A method of reacting 0.3 mol to 1.5 mol of a monoepoxy compound or a monoepoxy compound having a hydroxyl group with (2) 1 mol of a polyol having 3 to 6 hydroxyl groups. 3 to 1.5 mol of acid anhydride is reacted, and then 0.3 to 1.5 mol of monoepoxy compound or monoepoxy compound having a hydroxyl group is reacted, and further 2
A method of reacting 10 to 10 mol of lactone, and further (3) 3
2 to 10 per mol of polyol having 6 hydroxyl groups
There is a method of reacting mol of lactone, then reacting with 0.3 to 1.5 mol of acid anhydride and further reacting with 0.3 to 1.5 mol of monoepoxy compound or monoepoxy compound having a hydroxyl group. is there.

When the above reaction is carried out at 100 to 180 ° C., the acid anhydride group reacts with the hydroxyl group of the polyol to form an ester bond formed by the reaction with the hydroxyl group, and an extended portion having a carboxyl group at the terminal. Form. Lactone preferentially reacts with a hydroxyl group rather than a carboxyl group, and an ester bond formed by reacting with the hydroxyl group,
An extension having a hydroxyl group formed at the end is formed. The epoxy group of the monoepoxy compound reacts preferentially with the carboxyl group over the hydroxyl group to form an extension having an ester bond. At this time, a secondary hydroxyl group formed by the reaction of the carboxyl group and the epoxy group is formed. The secondary hydroxyl group is useful for improving the adhesion to the subsequently applied coating film and improving the chipping resistance. Is. The length of the radial extension of the star-type or starburst-type polyester oligomer can be freely adjusted by considering the above-mentioned characteristics of the functional group in the raw material reactant to be used and the structure of the reactant. Also, the number of radial extensions can be freely adjusted by the number of hydroxyl groups of the polyol used. The structure of the hydroxyl group-containing polyester oligomer obtained by this method 1 (1) includes, for example, one represented by the following formula (7). In addition,
In this example, a polyol having four hydroxyl groups is used as the polyol. When the number of hydroxyl groups is 3, the number of radial extension portions is 3, and when the number of hydroxyl groups is 6, the number of extension portions is 6.

[0025]

Embedded image In the formula, R ^{1 to} R ³ are ester bonds generated by the reaction between the hydroxyl group of the polyol and the intramolecular ester group of the lactone. R ⁴ is an ester bond generated by the reaction between the hydroxyl group of the polyol and the acid anhydride group. R ⁵ is an ester bond formed by the reaction between a carboxyl group derived from an acid anhydride and an epoxy group of a monoepoxy compound.
The extension from R ⁵ that branches from the portion having an OH group is a hydrocarbon portion derived from a monoepoxy compound. When a polyester oligomer is produced using a monoepoxy compound having a hydroxyl group as the monoepoxy compound, a starburst type polyester oligomer represented by the following formula (8) is obtained.

[0026]

[Chemical 9] In the formula, R ^{1 to} R ⁵ are as defined above. Method 1 (2)
In comparison with Method 1 (1), the order of the reaction between the lactone and the monoepoxy compound is reversed. However, since the reactivity between the lactone and the monoepoxy compound is selective, the method (1) Along with the polyester oligomer having the same structure as described above, a hydroxyl group-containing polyester oligomer having a different structure represented by the following formula (9) is obtained.

[0027]

[Chemical 10] In the formula, R ^{1 to} R ⁵ are as defined above. Also, R ⁶ is
It is an ester bond generated by the reaction between a hydroxyl group derived from a monoepoxy compound and a lactone. In Method 1 (3), when the amount of lactone used is increased, for example, a hydroxyl group-containing polyester oligomer represented by the following formula (10) is produced.

[0028]

[Chemical 11] In the formula, R ^{1 to} R ⁴ are ester bonds generated by the reaction between the hydroxyl group of the polyol and the intramolecular ester group of the lactone. R ⁵ is an ester bond generated by the reaction between the hydroxyl group derived from the lactone and the acid anhydride group. R ⁶ is an ester bond formed by the reaction between a carboxyl group derived from an acid anhydride and an epoxy group of a monoepoxy compound. The extension that branches from R ⁶ to the portion having an OH group is a hydrocarbon portion derived from a monoepoxy compound. When a monoepoxy compound containing a hydroxyl group is used as the monoepoxy compound, a polyester oligomer branched at the end of the radial extension is produced. On the other hand, when the amount of lactone used is small, for example, a polyester oligomer represented by the following formula (11) is formed.

[0029]

[Chemical 12] In the formula, R ^{1 and} R ² are ester bonds generated by the reaction between the hydroxyl group of the polyol and the intramolecular ester group of the lactone. R ³ is an ester bond generated by the reaction between the hydroxyl group of the polyol and the acid anhydride group. R ⁴ is an ester bond formed by the reaction between a carboxyl group derived from an acid anhydride and an epoxy group of a monoepoxy compound. R ⁴
Therefore, the extension portion branched from the portion having the OH group is a hydrocarbon portion derived from the monoepoxy compound. If a monoepoxy compound containing a hydroxyl group is used as the monoepoxy compound in the same manner as described above, a hydroxyl group-containing polyester oligomer in which the terminal of the radial extension is branched is produced. When the lactone is used in an amount around equivalent to the hydroxyl group of the polyol, the hydroxyl group-containing polyester oligomer represented by the formula (7) obtained by the method 1 is also produced. Method 2 In this method, 1 mole of a polyepoxy compound having 3 to 6 epoxy groups is reacted with 2 to 6 moles of a hydroxy acid having a hydroxyl group and a carboxyl group, and then 2
It is a method of reacting 10 mol of lactone. Method 2
In the case of using a large amount of lactone, for example, a polyester oligomer represented by the following formula (12) can be mentioned.

[0030]

[Chemical 13] In the formula, R ^{1 to} R ⁴ are ester bonds formed by the reaction between the epoxy group and the carboxyl group of the hydroxy acid. R ⁵ , R ⁷ , R ⁹ and R ¹¹ are ester bonds formed by the reaction between the hydroxyl group derived from the hydroxy acid and the intramolecular ester bond of the lactone. R ⁶ , R ⁸ , R ¹⁰ and R ¹² are ester bonds formed by the reaction between the secondary hydroxyl group formed by the reaction between the epoxy group and the carboxyl group of the hydroxy acid and the intramolecular ester bond of the lactone. This polyester oligomer is a typical starburst type polyester oligomer. On the other hand, when the lactone is used in a small amount, for example, a polyester oligomer represented by the following formula (13) is obtained.

[0031]

Embedded image In the formula, R ^{1 to} R ⁴ are ester bonds formed by the reaction between the epoxy group and the carboxyl group of the hydroxy acid. R ^{5 to} R ⁸ are ester bonds formed by the reaction between the hydroxyl group derived from the hydroxy acid and the intramolecular ester bond of the lactone. This polyester oligomer is a kind of star type polyester oligomer. Method 3 This method is a method in which 1 mol of a polyepoxy compound having 3 to 6 epoxy groups is reacted with 2 to 6 mol of a fatty acid, and then reacted with 2 to 10 mol of a lactone. In this method, when the lactone is used in an approximately equivalent amount to the epoxy group, for example, a polyester oligomer having a structure represented by the following formula (14) is obtained.

[0032]

[Chemical 15] In the formula, R ^{1 to} R ⁴ are ester bonds formed by the reaction between the epoxy group and the carboxyl group of fatty acid. R ⁵ ~
R ⁸ is an ester bond formed by the reaction between the secondary hydroxyl group generated by the reaction between the epoxy group and the carboxyl group of the fatty acid and the intramolecular ester bond of the lactone. Here, the rod-shaped extension part branched from R ^{1 to} R ⁴ is a hydrocarbon part derived from a fatty acid. This polyester oligomer is almost a star type polyester oligomer. In addition, when using a small amount of lactone, the length of the extension part extended by lactone becomes short. On the other hand, when a large amount of lactone is used, the extension part by lactone becomes long. The polyols used in the above reaction include triol, tetraol, pentaol, and hexaol. As the triol, for example, glycerin, trimethylolethane, trimethylolpropane,
Examples include trishydroxymethylaminomethane and 1,2,6-hexanetriol. Examples of tetraols include pentaerythritol, diglycerin, lyxose, and sorbitol. Examples of pentaol include mannose. Examples of hexaol include inositol. In particular, it is preferable to use triol or tetraol because of the ease of synthesis.

The amount of the polyol used is generally 3 to 40 based on the weight of the hydroxyl group-containing polyester oligomer.
%, Preferably 3 to 30%. Examples of the acid anhydride include phthalic anhydride, alkyl phthalic anhydride such as 4-methylphthalic anhydride, hexahydrophthalic anhydride, 3-methylhexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride and the like. Examples thereof include alkylhexahydrophthalic anhydride, succinic anhydride, and tetrahydrophthalic anhydride. In particular, it is preferable to use alkyl phthalic anhydride or alkylhexahydrophthalic anhydride because of the ease of synthesis. The amount of acid anhydride used is generally 3 to 30%, preferably 3 to 20%, based on the weight of the hydroxyl group-containing polyester oligomer. Examples of the lactone include ε-caprolactone,
Examples include β-propiolactone, γ-butyrolactone, and δ-valerolactone. From the viewpoint of ease of synthesis, it is preferable to use ε-caprolactone as the lactone. As described above, the amount of lactone used is preferably 31 to 85%, and particularly preferably 31 to 80% based on the weight of the hydroxyl group-containing polyester oligomer in view of the relationship with the amount of lactone modification.

As the monoepoxy compound, an epoxide of an aliphatic hydrocarbon having an unsaturated bond, particularly an epoxide of an α-olefin, a glycidyl ether, a glycidyl ester or the like can be preferably used. α
-The epoxide of olefin has 3 to 25 carbon atoms.
The epoxides of are preferred. For example, propylene oxide, AOEX24 (epoxide mixture of α-olefin having 12 and 14 carbon atoms) and AOEX68 (16 and 1 carbon atoms).
Epoxide mixture of α-olefin of 8) (above, manufactured by Daicel Chemical Industries) and the like. Examples of the glycidyl ether include butyl glycidyl ether, phenyl glycidyl ether, decyl glycidyl ether, cresyl glycidyl ether, and the like.
Examples of the glycidyl ester include Khajura E10 and PES10 (all manufactured by Yuka Shell Epoxy). The number of carbon atoms in the monoepoxy compound is preferably 4 to 22 from the viewpoint of easiness of synthesis and physical properties of the coating film obtained. Particularly preferred monoepoxy compound has 4 carbon atoms.
~ 15. The hydroxyl group-containing monoepoxy compound is obtained by further introducing a hydroxyl group into the above monoepoxy compound. Specifically, 1,2-epoxyhexanol, 1,
2-epoxyoctanol, 1,2-epoxydecanol, hydroxybutyl glycidyl ether, hydroxyoctyl, glycidyl ether, hydroxyphenyl glycidyl ether, hydroxybutyl glycidyl ester, hydroxycyclohexyl glycidyl ester and the like can be mentioned.

However, the monoepoxy compound and the hydroxyl group-containing monoepoxy compound may be used in combination. Examples thereof include a mixture of a monoepoxy compound having an aliphatic hydrocarbon group having 4 to 22 carbon atoms and a hydroxyl group-containing monoepoxy compound which may or may not have such an aliphatic hydrocarbon group. To be As such a hydroxyl group-containing monoepoxy compound, a hydroxyl group-containing monoepoxy compound having 3 to 15 carbon atoms is used. Specifically, glycidol can be preferably used. When used in combination, the amount of the hydroxyl group-containing monoepoxy compound used is 2 to 100%, preferably 4 to 90%, based on the weight of the mixture of the monoepoxy compounds. The amount of the monoepoxy compound or the hydroxyl group-containing monoepoxy compound used is generally from 5 to 45%, preferably from 5 to 30%, based on the weight of the hydroxyl group-containing polyester oligomer. The hydroxy acid is not particularly limited as long as it has a hydroxyl group and a carboxyl group in the molecule. Examples of such a hydroxy acid include pivalic acid, 12-
Preferred examples include linear or branched hydroxyalkyl acids such as hydroxystearic acid, and reaction products obtained by reacting a polyol with a compound having an acid anhydride group. Examples of the polyol used in this case include ethylene glycol, propylene glycol, 1,5-hexanediol, 1,6-hexanediol, neopentyl glycol, cyclohexanedimethanol, and other diols, trimethylolpropane, and trimethylolpropane. Trihydric alcohols such as methylolethane and glycerin, pentaerythritol,
Examples thereof include tetrahydric alcohols such as diglycerin.
As the compound having an acid anhydride group, the acid anhydride described above can be mentioned as a preferable example.

The amount of hydroxy acid used is generally from 5 to 7 based on the weight of the hydroxyl group-containing polyester oligomer.
It is 0%, preferably 10 to 60%. Examples of the polyepoxy compound having 3 to 6 or more epoxy groups in one molecule include trisglycidyl isocyanurate, trisglycidylpropyl isocyanurate, and the like.
Examples thereof include tetraglycidyl metaxylenediamine, tetraglycidyl-1,3-bisaminomethylcyclohexane, tetraglycidyl diaminodiphenylmethane, triglycidyl p-aminophenol, and diglycidyl aniline. The amount of polyepoxy compound used is generally 5-40%, preferably 10-30%, based on the weight of the hydroxyl group-containing polyester oligomer. As the fatty acid, a fatty acid having 4 to 22 carbon atoms, and more preferably 4 to 15 carbon atoms is used. Examples of such fatty acids include butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, onanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, and heptadecanoic acid. used.

The amount of fatty acid used is generally 5 to 70%, based on the weight of the hydroxyl group-containing polyester oligomer.
It is preferably 10 to 60%. The aliphatic hydrocarbon group having 4 to 22 carbon atoms which is not derived from lactone is preferably derived from a monoepoxy compound, a hydroxyl group-containing monoepoxy compound, a hydroxy acid or a fatty acid. Therefore, in order to reliably introduce such an aliphatic hydrocarbon group into the polyester oligomer, it is necessary to use a compound containing an aliphatic hydrocarbon group having 4 to 22 carbon atoms. The polyester oligomer containing a blocked hydroxyl group can be easily prepared by blocking the above-mentioned polyester oligomer containing a hydroxyl group.
As the reaction conditions used for preparing the above-mentioned hydroxyl group- or blocked hydroxyl group-containing polyester oligomer, the conventionally known conditions used for the esterification reaction are adopted.
Usually, in this synthesis, a catalyst that promotes the reaction of lactone, a catalyst that promotes the reaction of a carboxyl group and an epoxy group, and the like are used. As the lactone reaction catalyst, for example, phosphoric acid monoesters, Bronsted acids such as hydrochloric acid and sulfuric acid, titanate compounds such as tetrabutyl titanate, and organic tin compounds such as dibutyltin dilaurate and dimethyltin dichloride can be preferably used. .

The reaction between the carboxyl group and the epoxy group is
Although it is possible without a catalyst, in order to shorten the reaction time, as a catalyst, for example, imidazole such as 1-methylimidazole and dimethylimidazole, quaternary phosphonium salts such as tetrabutylphosphonium bromide and tetralaurylphosphonium chloride, tetraammonium Bromide and quaternary ammonium salts such as tetraammonium chloride and trilauryl ammonium acetate are preferably used. These catalysts are used in catalytic amounts. Specifically, in the case of a lactone reaction catalyst,
For example, the amount of lactone used is 0.0001 to 1
0% by weight, preferably 0.0001 to 1% by weight, and in the case of a reaction catalyst of a carboxyl group and an epoxy group, for example, 0.001 to 10% by weight, preferably
It is 0.001 to 5% by weight. The reaction temperature is generally 100.
-200 degreeC, Preferably it is 120-180 degreeC. The reaction time is 30 minutes to 48 hours, preferably 3 to 1
2 hours. The glass transition temperature (Tg) of the polyester oligomer used in the present invention is preferably -35 ° C to
The temperature is 40 ° C, particularly preferably -30 to 20 ° C. −35
When the glass transition temperature is lower than 0 ° C, the coating film becomes too soft and the gasoline resistance and the like are lowered too much, which is not preferable. on the other hand,
When the glass transition temperature is higher than 40 ° C., the viscosity becomes too high, which is also not preferable.

In the polyester oligomer used in the present invention, the reaction amount (lactone modification amount) of lactone in one molecule is 31 to 85%, and a straight chain or branched chain having 4 to 22 carbon atoms which is not derived from lactone. It is preferred to include an aliphatic chain consisting of chains. If the lactone modification amount is less than 31%, the solubility is likely to decrease, the viscosity of the oligomer increases, and the polyester oligomer has poor flexibility, so the coating film becomes brittle when formed. , Chipping resistance and the like are likely to decrease.
On the other hand, when the lactone modification amount is more than 85%, the coating film becomes too soft and the gasoline resistance is deteriorated, which is also not preferable. The preferred lactone modification amount is 31 to 80.
%, Particularly preferred is 31-75%. Furthermore, when there is no aliphatic hydrocarbon group having 4 to 22 carbon atoms that is not derived from lactone, the compatibility between the hydroxyl group-containing polyester oligomer and the curing agent tends to be poor, and crosslinking is difficult to occur, resulting in poor coating performance. The finished appearance tends to deteriorate significantly. Particularly preferred carbon number of the aliphatic hydrocarbon group is 4 to
15 and more preferably 4 to 12 carbon atoms. The aliphatic hydrocarbon group is a monovalent or divalent aliphatic hydrocarbon group, which may be linear or branched.
Examples of the monovalent aliphatic hydrocarbon group include saturated or unsaturated aliphatic hydrocarbon groups such as alkyl groups, alkenyl groups and alkynyl groups. Examples of such monovalent aliphatic hydrocarbon groups include n-butyl group, s-butyl group, t-butyl group, n-pentyl group, s-pentyl group, hexyl group, n-heptyl group, s -Alkyl groups such as heptyl group, octyl group, nonyl group, decyl group, and undecyl group, and n-
Alkenyl such as butenyl, s-butenyl, t-butenyl, n-pentenyl, s-pentenyl, hexenyl, n-heptenyl, s-heptenyl, octenyl, nonenyl, decenyl, uncenyl Group, further n-butynyl group, s-butynyl group, t-butynyl group, n-pentynyl group, s-pentynyl group, hexynyl group, n-heptynyl group,
Examples thereof include alkynyl groups such as s-heptynyl group, octynyl group, nonynyl group, decynyl group, and uncesinyl group. As a preferable alkyl group, specifically, n
-Butyl, s-butyl, n-pentyl, s-pentyl,
Hexyl, n-heptyl, s-heptyl, octyl, nonyl, denyl, undecyl and the like can be mentioned.

On the other hand, as the divalent aliphatic hydrocarbon group,
Examples thereof include saturated or unsaturated aliphatic hydrocarbon groups such as alkylene groups, alkenylene groups and alkynylene groups. Examples of such a divalent aliphatic hydrocarbon group include an alkylene group such as a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an ethylethylene group and an ethylpropylene group, a butenylene group and a pentenylene group. ,
Hexenylene group, heptenylene group, octenylene group, nonenylene group, decenylene group, undecenylene group, dodecenylene group, tridecenylene group, tetradecenylene group, etc. alkenylene group, butynylene group, pentynylene group, hexynylene group, heptynylene group, octynylene group, And alkynylene groups such as undecynylene group, dodecynylene group, tridecynylene group and tetradecynylene group. The polyester oligomer used in the present invention can be used in combination with a hydroxyl group-containing polyester oligomer whose lactone modification amount is not within the range of the present invention. When used in combination, the amount of the polyester oligomer of the present invention used is 20 based on the total weight of the mixture.
˜99.9%, preferably 30-99.9%. As the functional group of the oligomer, a hydrolyzable silyl group obtained by blocking the hydroxyl group of the silanol group with a hydrolyzable group may be used together. The silanol group optionally used in the present invention has the following formula:

[0041]

Embedded image (In the formula, R ¹ and R ² , which may be the same or different, are a hydroxyl group, an alkyl group, an alkoxy group, a —NR ¹ R ² group (provided that R ¹
And R ² is an alkyl group or an aryl group), —NR ¹ CO
R ² (provided that R ¹ and R ² are alkyl groups or aryl groups), —COR ¹ group (provided that R ¹ is an alkyl group or aryl group), —OCOR ¹ group (provided that R ¹ Is an alkyl group or an aryl group), an aryl group, a -ONR ¹ R ² group (provided that R ¹
And R ² is an alkyl group or an aryl group), —ONCR ¹
R ² group (provided that R ¹ and R ² are an alkyl group or an aryl group). ). In the above formula, the alkyl group includes a linear or branched alkyl group having 1 to 10 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group,
Examples thereof include s-butyl group, t-butyl group and pentyl group.
Examples of the alkoxy group include those having an alkyl group portion similar to the above alkyl group. The aryl group particularly includes a substituted or unsubstituted phenyl group, and examples of the substituent include a halogen atom, an alkyl group, an alkoxy group and the like. Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom or an iodine atom. The alkyl group as a substituent includes a linear or branched alkyl group having 1 to 10 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, s- Examples thereof include a butyl group, a t-butyl group and a pentyl group. Moreover, as the alkoxy group as a substituent, the same alkyl group as the above-mentioned alkyl group can be mentioned. Examples of preferable substituents include a halogen atom such as a fluorine atom and a lower alkyl group having 1 to 5 carbon atoms. Further, the hydrolyzable silyl group is a silanol group blocked by a hydrolyzable group,
The general formula is as follows.

[0042]

[Chemical 17] In the above formula (16), R ¹ and R ² are the same as those in formula (15), and R ³ is an alkyl group, a —NR ¹ R ² group (provided that R ¹ and R ²
R ² is an alkyl group or aryl group), —COR ¹ group (provided that R ¹ is an alkyl group or aryl group), aryl group, —NR ¹ R ² group (provided that R ¹ and R ² Is an alkyl group or an aryl group), -NCR ¹ R ² group (provided that R ¹ and R
² is an alkyl group or an aryl group). ). The vinyl polymerized oligomer (I) having such a silanol group or a hydrolyzable silyl group polymerizes (copolymerizes) a vinyl polymerizable monomer such as an acrylic monomer having such a silanol group or a hydrolyzable silyl group. It can be manufactured. As such a monomer, various monomers can be appropriately selected and used. For example, as a typical monomer having a silanol group or a hydrolyzable silyl group, for example, a monomer having a silanol group or a hydrolyzable silyl group and a radical polymerizable unsaturated bond is suitable.
As the radical-polymerizable unsaturated bond, a vinyl-polymerizable monomer whose hydroxyl group is a silanol group or a hydrolyzable silyl group in the above formula (4) can be preferably used.

Specific examples of such vinyl-polymerizable monomers include, for example, γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane and γ- (meth) acryloxypropyl. Tripropoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropylmethyldiethoxysilane, γ- (meth)
Acryloxypropylmethyldipropoxysilane, γ-
(Meth) acryloxybutylphenyldimethoxysilane, γ- (meth) acryloxyphenyldiethoxysilane, γ- (meth) acryloxyphenyldipropoxysilane, γ- (meth) acryloxypropyldimethylmethoxysilane, γ- (meth ) Acryloxypropyldimethylethoxysilane, γ- (meth) acryloxypropylphenylmethylmethoxysilane, γ- (meth) acryloxypropylphenylmethylethoxysilane, γ- (meth) acryloxypropyltrisilanol, γ- (meth) Acryloxypropylmethyldihydroxysilane,
γ- (meth) acryloxybutylphenyldihydroxysilane, γ- (meth) acryloxypropyldimethylhydroxysilane, γ- (meth) acryloxypropylphenylmethylhydroxysilane and the like can be mentioned.

The amount of silanol groups and / or hydrolysable silyl groups optionally used is preferably up to 3.5 mol / kg resin, preferably 0.1 to 2.0 mol / kg resin. If this amount exceeds 3.5 mol / kg-resin, the amount of alcohol volatilized by removing the alkoxy groups increases, the coating film after crosslinking becomes brittle, and cracks easily occur, which is not preferable. In the present invention, the alicyclic epoxy group-containing compound used together with the above-mentioned oligomer containing a hydroxyl group or a blocked hydroxyl group contains a plurality of alicyclic epoxy groups in one molecule and has a molecular weight of 230 to 800. The alicyclic epoxy group is a 5- or 6-membered alicyclic hydrocarbon group (which may include a bridged hydrocarbon) in which an oxygen atom is epoxy-bonded between adjacent carbon atoms of the ring. Is. When the amount of the alicyclic epoxy group in the alicyclic epoxy group-containing compound is less than 2 per molecule, the crosslinking becomes insufficient and a coating film having desired properties cannot be formed. A preferable amount of the functional group is 2 to 5, particularly preferably 2 to 1 per molecule.
It is 4. If the number of alicyclic epoxy groups is less than 2, it is not preferable because crosslinking does not occur. On the other hand, when the number is more than 5, the viscosity becomes too high and the coating film becomes brittle, which is not preferable.

When the molecular weight of the alicyclic epoxy group-containing compound is less than 230, the volatility is increased and the crosslinking is insufficient, so that a coating film having desired properties cannot be formed.
On the other hand, when the molecular weight exceeds 800, the viscosity of the coating material becomes too high, and it is not possible to sufficiently achieve low solvent. The preferred molecular weight is 230-600. The compound containing an alicyclic epoxy group can be used without particular limitation as long as it satisfies the above conditions. As a preferable alicyclic epoxy group-containing compound, an alicyclic epoxy group-containing compound represented by the following formula (17) is preferable.

[0046]

Embedded image Here, X and Y are independently an alicyclic epoxy group,
m, n, and l are independently 0 or an integer of 1-5.
Preferred examples of the alicyclic epoxy group-containing compound represented by the above formula include the following.

[0047]

[Chemical 19] Specific compounds include Celoxide 2021, Celoxide 2081, and Celoxide 2083 (all manufactured by Daicel Chemical Industries, Ltd.). In the coating material of the present invention, the molar ratio of oligomer / alicyclic epoxy group-containing compound is 1 / 0.7 to 1-20. When this ratio is less than 1 / 0.7, it becomes difficult to reduce the amount of the organic solvent to 40% or less due to the low solvent. On the other hand, when this ratio exceeds 1/20, the crosslink density becomes excessive, and the chipping resistance, weather resistance, etc. are reduced. The preferred ratio is 1/1 to 1/20,
A particularly preferred ratio is 1/1 to 1/15. The cationically polymerizable catalyst used in the coating material of the present invention has a function of opening the alicyclic epoxy group to promote polymerization. As such a cationically polymerizable catalyst, the following catalysts can be preferably used. Such catalysts can be divided into those containing silicon atoms and those not containing silicon atoms. (1) Cationic Polymerization Catalyst Containing Silicon Atom As such a cationic polymerization catalyst, an organometallic chelate is used. The organometallic chelate typically includes an organoaluminum chelate, an organozirconium chelate and an organotitanium chelate, and particularly, a compound capable of forming a keto / enol tautomer is a coordination that forms a stable chelate ring. The compound included as a child can be mentioned. The organometallic chelate also acts as a dissociation catalyst when using a hydrolyzable silyl group.

Examples of the compound capable of forming the keto-enol tautomer include β-diketones such as acetylacetone, acetoacetic acid esters such as ethyl acetoacetate, malonic acid esters such as ethyl malonate and propyl malonate, and diacetone. A ketone having a hydroxyl group at the β-position such as alcohol, an aldehyde having a hydroxyl group at the β-position such as methyl salicylate, and the like can be used. Particularly, β-diketone and acetoacetic acid ester are preferable. Organometallic chelates can generally be synthesized by reacting the keto-enol tautomer with a metal alcoholate, such as an aluminum alcoholate, a titanium alcoholate or a zirconium alcoholate. As the organic aluminum chelate, for example, 1 mol of the aluminum alcoholate represented by the following formula is usually mixed with about 3 mol or less of the compound capable of forming the keto-enol tautomer, and the mixture is heated if necessary. By doing so, it can be easily prepared.

[0049]

Embedded image In the above formula, R ¹ , R ² and R ³ may be the same or different,
A linear or branched alkyl or alkenyl group having 1 to 18 carbon atoms. As such an alkyl group,
For example, methyl group, ethyl group, propyl group, butyl group,
s-butyl group, t-butyl group, pentyl group, hexyl group,
Examples thereof include a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group and an octadecyl group. Examples of the alkenyl group include a vinyl group and an allyl group. Examples of the aluminum alcoholate represented by the above formula include aluminum trimethoxide, aluminum triethoxide, aluminum tri-2-propoxide, aluminum triisopropoxide, aluminum tributoxide and the like. The organotitanium chelate is prepared, for example, by mixing the compound capable of forming the keto-enol tautomer in an amount of about 4 mol or less with 1 mol of titanium of the titanate represented by the following formula, and if necessary, It is obtained by heating by heating.

[0050]

[Chemical 21] R ¹ , R ² , R ³ , R ⁴ and R ⁵ in the above formula are represented by the above formula (1
It is the same as R ¹ , R ² and R ³ in 8). Also, n is
An integer of 0 to 20 is shown. Specific compounds represented by the above formula (19) in which n is 0 include, for example, tetramethyl titanate, tetraethyl titanate, tetra n-propyl titanate, tetraisopropyl titanate, tetraisobutyl titanate, tetra n-butyl titanate and tetra t -Butyl titanate, tetra n-pentyl titanate,
Tetra n-lauryl titanate and the like can be mentioned. Particularly, tetraisopropyl titanate, tetraisobutyl titanate and tetra n-butyl titanate are preferable. Also,
Specific compounds in which n in the above formula (27) is 1 or more include, for example, tetraisopropyl titanate, tetraisobutyl titanate and tetra n-butyl titanate 2
Monomers to 11-mers can be used. The organic zirconium chelate is obtained by, for example, mixing the compound capable of forming the keto-enol tautomer with 1 mol of zirconium of the zirconate represented by the following formula in an amount of usually 4 mol or less, and if necessary, It can be produced by heating.

[0051]

[Chemical formula 22] R ¹ , R ² , R ³ , R ⁴ and R ⁵ and n in the above formula are the same as those in the above formula (19). Is. Specific compounds in which n is 0 in the above formula include, for example,
Tetramethyl zirconate, tetraethyl zirconate, tetra n-propyl zirconate, tetraisopropyl zirconate, tetraisobutyl zirconate, tetra n-butyl zirconate, tetra t-butyl zirconate, tetra n-pentyl zirconate, tetra n- Examples thereof include lauryl zirconate. Particularly, tetraisopropyl zirconate, tetraisobutyl zirconate and tetra n-butyl zirconate are preferable. Further, as a specific compound in which n in the above formula (20) is 1 or more,
For example, tetraisopropyl zirconate, tetraisobutyl zirconate, and tetra n-butyl zirconate dimer to 11mer monomers can be used.
As the cationically polymerizable catalyst containing the above silicon atom,
Organoaluminum chelate catalysts are preferable in terms of excellent curability of the paint.

The metal alcoholate used for forming the above-mentioned organometallic chelate can also be used as a preferable cationic catalyst. Of these, aluminum alcoholate is particularly preferable. (2) Cationic Polymerization Catalyst Not Containing Silicon Atom (i) Protonic Acid or Protonic Acid Neutralized with Lewis Base Examples of the protonic acid include phosphoric acid, phosphoric acid mono- or diesters, polyphosphoric acid esters and boric acid. , Boric acid mono- or diester, trifluoroacetic acid and the like. As the alcohol constituting the ester group of the protonic acid ester, n-propanol, n-butanol,
Examples thereof include primary alcohols such as n-hexanol and n-octanol, or secondary alcohols such as isopropanol, s-butanol and s-hexanol. Examples of the Lewis base include ammonia, monoethylamine, triethylamine, pyridine, piperidine, aniline, morpholine, cyclohexylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, and other amines, trialkylphosphines, triarylphosphines, and the like. Phosphine, triaryl phosphite, and the like.

(Ii) Lewis acid or Lewis acid neutralized with Lewis base Examples of the Lewis acid include boron trifluoride, boron trifluoride diethyl ether complex, aluminum trichloride,
Examples thereof include iron trichloride, tin tetrachloride, zinc dichloride, titanium tetrachloride and the like. On the other hand, examples of the Lewis base used to neutralize the Lewis acid include those listed above. (iii) Phosphoric acid ester The phosphoric acid ester represented by the following formula (21) may be mentioned.

[0054]

[Chemical formula 23] In the above formula, R ¹ is an alkyl group having 3 to 10 carbon atoms,
A cycloalkyl group having 5 to 10 carbon atoms and an aryl group having 6 to 20 carbon atoms, and m is 1 or 2. The alkyl group as R ¹ includes a linear or branched alkyl group, for example, propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, n-pentyl group, hexyl Group, heptyl group, octyl group and the like. The cycloalkyl group as R ¹ includes a linear or branched cycloalkyl group, for example, a cyclopentyl group, a 2-methylcyclopentyl group, a cyclohexyl group,
A cyclopentyl group and the like are included. The aryl group as R ¹ includes a phenyl group or a naphthyl group which may have a substituent. The range of the substituents is the same as that of R ^{1 in} formula (28). Specific compounds include, for example, primary alcohols such as n-propanol, n-butanol, n-hexanol and n-octanol, or secondary alcohols such as isopropanol, s-butanol, s-hexanol and cyclohexanol.
Mention may be made of phosphoric acid mono- or diesters of primary alcohols.

(Iv) Onium Salt Examples of onium salts include those represented by the following formula. _{^{[R 1 3 NR 2] +}} X - (22) [R 1 3 PR 2] + X - (23) [R 1 2 OR 2] + X - (24) [R 1 2 SR 2] + X - ( 25) In each of the above formulas, R ¹ is an alkyl group, an alkenyl group,
An aryl group, an alkaryl group, an alkanol group or a cycloalkyl group, wherein two R ^1's are bonded to each other to form N,
A heterocycle having P, O or S as a hetero atom may be formed. The alkyl group as R ¹ has, for example, 1 carbon atom.
To 12 linear or branched alkyl groups are included, for example, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, n-pentyl group, hexyl group. Group, heptyl group, octyl group and the like. The alkenyl group as R ¹ has 3 to 12 carbon atoms.
The straight-chain or branched alkenyl group is included, and examples thereof include a propenyl group, a butenyl group, and a pentenyl group.

The aryl group as R ¹ is, for example,
A substituted or unsubstituted phenyl group or naphthyl group is included. Examples of the substituent include a halogen atom and a carbon number of 1
A C8 alkyl group, a C5-7 cycloalkyl group or a C1-8 alkoxy group. Examples of the alkaryl group as R ¹ include those formed of the above alkyl group and aryl group. The alkanol group as R ¹ includes, for example, an alkanol group which may have a branch having 1 to 12 carbon atoms, and includes, for example, ethanol group, propanol group, n-butanol group, s-butanol group, t -Butanol group, n-pentanol group, s-pentanol group and the like can be mentioned. The cycloalkyl group as R ¹ has, for example, 5 to 10 carbon atoms which may have a branch.
A cycloalkyl group of, for example, a cyclopentyl group, a 2-methylcyclopentyl group, a cyclohexyl group,
A cyclopentyl group and the like are included. Examples of X ⁻ include SbF ₆ ⁻ , AsF ₆ ⁻ , PF ₆ ⁻ or BF ₄ ⁻ .
Among the above cationically polymerizable catalysts, those obtained by neutralizing a protonic acid with a Lewis base, those obtained by neutralizing a Lewis acid with a Lewis base, and the compounds represented by the above formulas (22) to (25) are thermal latent cations. Called a polymerizable catalyst, for example 50-200 ℃
By heating to a temperature, a cationically polymerizable catalyst is formed and the curing of the resin is catalyzed. When such a heat-latent cationically polymerizable catalyst is used, the curing reaction will not be catalyzed unless it is heated. Therefore, even if it is stored as one liquid, it may thicken or gel during long-term storage. Easy to handle.

As such a heat-latent cationically polymerizable catalyst, preferred are quaternary ammonium salts,
Included are sulfonium salts, phosphonium salts and iodonium salts. Examples of the quaternary ammonium salt include N, N-
Dimethyl-N-benzylanilinium antimony hexafluoride, N, N-Dimethyl-N-benzylanilinium boron tetrafluoride, N, N-Dimethyl-N-benzylpyridinium antimony hexafluoride, N, N-diethyl-N -Benzyltrifluoromethanesulfonic acid, N, N-dimethyl-N- (4-methoxybenzyl) pyridinium antimony hexafluoride, N, N-diethyl-N
Examples include-(4-methoxybenzyl) pyridinium antimony hexafluoride and N, N-diethyl-N- (4-methoxybenzyl) toludinium antimony hexafluoride. Examples of the sulfonium salt include triphenylsulfonium boron tetrafluoride, triphenylsulfonium antimony hexafluoride, triphenylsulfonium hexafluoroarsenide, ADEKA CP-66 (manufactured by Asahi Denka Kogyo), ADEKA CP-77 (Asahi Denka Kogyo) Manufactured), tri (4-methoxyphenyl) sulfonium hexafluoroarsenic, diphenyl (4-phenylthiophenyl) sulfonium hexafluoroarsenic, and the like.

Examples of the phosphonium salt include ethyltriphenylphosphonium antimony hexafluoride and tetrabutylphosphonium antimony hexafluoride. Examples of the iodonium salt include diphenyliodonium hexafluoroarsenic, di4-chlorophenyliodonium hexafluoroarsenic, di4-bromophenyliodonium hexafluoroarsenic, di-p-triiodonium hexafluoroarsenic, and phenyl (4-methoxy). (Phenyl) iodonium arsenic hexafluoride and the like. The above cationically polymerizable catalyst is used in a catalytic amount in the low solvent type coating composition of the present invention.
Specifically, with respect to 100 parts by weight of the total solid content of the coating composition (I) of the present invention, 0.01 to 30 parts by weight, preferably 0.1 to 1 is used.
Used in an amount of 0 parts by weight. When the amount of the cationically polymerizable catalyst is too small, the coating film and the curability are deteriorated. On the other hand, when the amount is too large, the coating film is cured before coating or the coating film is discolored. Is deteriorated, which is not preferable. When a heat-latent cationically polymerizable catalyst is used, it is usually 50 to 200 ° C, preferably 60 to 17 ° C.
By heating at 0 ° C. for 2 minutes to 1 hour, for example, the curing of the resin composition can be promoted. However, when the coating composition is used as a two-pack type, the two-pack type is mixed immediately before use, so it is not necessary to consider the curing of the resin so much. There is no particular.

In the present invention, a curing agent which reacts with a hydroxyl group derived from an oligomer can be added. As such a curing agent, any curing agent conventionally used in a curing system of an oligomer having a hydroxyl group can be used without particular limitation. As such a curing agent, for example, an isocyanate curing agent such as polyisocyanate or isocyanate prepolymer, or an amino resin curing agent such as melamine resin, benzoguanamine resin or urea resin is used. As the polyisocyanate, a polyisocyanate having a plurality of isocyanate groups is used. The number of isocyanate groups is generally 2-6, preferably 2-4. Diisocyanate is particularly preferably used as the polyisocyanate. Examples of such a diisocyanate include xylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, 1,4-tetramethylene diisocyanate, and 1,1.
0-decamethylene diisocyanate, 1,18-octadecamethylene diisocyanate, lysine diisocyanate, lysine triisocyanate and the like can be mentioned. Hexamethylene diisocyanate is preferred as these diisocyanates.

Examples of the isocyanate prepolymer include polymers of polyisocyanates and addition reaction products of polyisocyanates with water or polyhydric alcohols. Examples of the polyisocyanate polymer include a polyisocyanate compound in which a plurality of polyisocyanates are bonded to form a ring. Preferred examples of such a cyclic polyisocyanate include isocyanurates having an isocyanuric ring. Polyisocyanate reacts with water or a polyhydric alcohol to give an addition reactant having a plurality of isocyanate groups.
The burette is formed from the reaction of polyisocyanate with water. The polyhydric alcohol used here is 2
Alcohols having a valence of 3 or more, or 4 or more are listed,
For example, ethylene glycol, propylene glycol,
1,3-butylene glycol, 2-methylpropanediol, 1,4-butyryl glycol, neopentyl glycol, 1,6-hexane glycol, 1,2-dodecanediol, glycerin, trimethylolpropane, trimethylolethane, penta Examples thereof include erythritol, dipentaerythritol, hydroxypivalic acid neopentyl glycol ester, 1,4-cyclohexanedimethanol, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, and 1,4-hydroxyhydroquinone.

A preferred specific isocyanate prepolymer is hexamethylene diisocyanate prepolymer which is a cyclic polymer (for example, Pernock 901S).
(Manufactured by Dainippon Ink) and Duranate TPA-100 (manufactured by Asahi Kasei). As the amino resin type curing agent,
Melamine resins are preferred. Melamine resins are produced by the polymerization of melamine and formaldehyde, the production methods of which are well known to those skilled in the art. As such a melamine resin, a melamine resin containing 50 to 100% of a mononuclear melamine represented by the following formula (22) is particularly preferable.

[0062]

[Chemical formula 24] (In the formula, R ^{1 to} R ⁶ are independently a hydrogen atom, a methylol group or an alkyl group having 1 to 5 carbon atoms.) Here, the mononuclear melamine is more than 50% in the melamine resin. If it is blended in a small amount, the viscosity of the coating material becomes too large, which is not preferable. Formula (2
When the alkoxy group in 2) has more than 5 carbon atoms, the viscosity becomes too high, which is not preferable. The preferred carbon number is 1 to 4. Specifically, as such an alkoxy group, a methoxy group, an ethoxy group, a propoxy group,
Examples thereof include butoxy group and isobutoxy group. As the embodiment of the mononuclear melamine, R ^{1 to} R ⁶ in the above formula (22) are all alkoxy groups, a mixture of hydrogen atoms and methylol groups, a mixture of hydrogen atoms and alkoxy groups. And a mixture of a methylol group and an alkoxy group, and a mixture of a hydrogen atom, a methylol group and an alkoxy group. Specifically, Cymel 325, Cymel 327, and Cymel 370, which are commercially available from Mitsui Cyanamid (all of the above, in formula (22), R ^{1 to} R ⁶ are methylol groups, and the mononuclear melamine content is , 70%), and Cymel 303 (in the formula (22), R ^{1 to} R ⁶ are all alkoxy groups, and the mononuclear melamine content is 80%).

The mononuclear melamine represented by the formula (22) is different from the binuclear or more melamine of the type in which two or more melamines are mutually bound by formaldehyde, but in the above formula (22) As long as the amount of the mononuclear melamine shown is 50% or more, a melamine resin containing such a binuclear or higher melamine (polynuclear melamine resin) may be used in combination. The melamine resin containing 50 to 100% of the mononuclear melamine can be easily prepared by those skilled in the art. Generally, the amount of polynuclear melamine resin is adjusted to less than 50% or completely by reacting melamine represented by the formula (22) with formaldehyde and then fractionating by gel permeation chromatography. Can be removed. When an isocyanate prepolymer is used as a curing agent, the isocyanate prepolymer is generally in the range of 0.6-1. To 1 mol of the hydroxyl group of the hydroxyl group-containing polyester oligomer of the present invention.
4 mol, preferably 0.8 to 1.2 mol, particularly preferred
Used in an amount of 0.9-1.1 mol. When a melamine resin is used as the curing agent, the melamine resin is 20 to 14 relative to the weight of the hydroxyl group-containing polyester oligomer.
It is used in an amount of 0%, preferably 40-100.

As the curing agent, mononuclear melamine is 50 to 50%.
A melamine resin of 100% is particularly preferable for the purpose of lowering the viscosity. In the low solvent resin composition of the present invention, the above isocyanate prepolymer and melamine resin may be mixed and used. As a blending ratio in that case, the amount of the melamine resin is generally 0.1 to 99.9% by weight, preferably 0.1 to 5.0% by weight. The low-solvent coating composition of the present invention contains the above components, and if necessary,
Various pigments conventionally used in the field of paints (for example, color pigments and brighteners), anti-sagging agents or anti-settling agents, reverig agents, dispersants, defoamers, UV absorbers,
A light stabilizer, an antistatic agent, a thinner and the like can be appropriately mixed and prepared. Examples of the pigment or glittering agent include titanium oxide, carbon black, precipitated barium sulfate, calcium carbonate, talc, kaolin, silica, mica, aluminum, red iron oxide, lead chromate, lead molybdate, chromium oxide, cobalt aluminate, Azo pigments, phthalocyanine pigments, anthraquinone pigments and the like can be preferably used.

As the anti-sagging agent or the anti-settling agent, for example, bentonite, castor oil wax, amide wax, microgel (for example, MG100S (manufactured by Dainippon Ink and Chemicals)) and the like can be preferably used. As the leveling agent, for example, KF69, Kp321 and Kp301 (above,
Silicon-based materials such as Shin-Etsu Chemical), Modaflow (manufactured by Mitsubishi Monsanto), BYK358, 301 (manufactured by Big Chemie Japan), and Dia-Aid AD9001 (manufactured by Mitsubishi Rayon) can be preferably used. Examples of the dispersant include Anti-Terra U or Anti-Terra P and Disperbyk-10.
1 (above, manufactured by Big Chemie Japan) or the like can be preferably used. Examples of defoaming agents include BYK-O
(Manufactured by Big Chemie Japan) and the like can be preferably used. Examples of ultraviolet absorbers include Tinuvin 90.
Benzotriazole-based UV absorbers such as 0, TINUVIN 384, and TINUVIN P (manufactured by Ciba Geigy), and oxalic anilide UV absorbers such as SANDVA-3206 (manufactured by Sando) can be preferably used.

As the light stabilizer, for example, Tinuvin 123
Hindered amine light stabilizers such as Sankyo (manufactured by Sankyo) and Sandbar 3058 (manufactured by Sand) can be preferably used. Examples of the thinner include toluene, xylene,
Aromatic compounds such as ethylbenzene, alcohols such as methanol, ethanol, propanol, butanol, isobutanol, acetone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, isophorone, N-
A ketone such as methylpyrrolidone, an ester compound such as ethyl acetate, butyl acetate, methyl cellosolve, or a mixture thereof can be used. As the antistatic agent, for example, Esocard C25 (manufactured by Lion Armor) or the like can be preferably used. The low-solvent type coating composition of the present invention is particularly an intermediate coating used for coating automobile bodies, bumpers, etc., a solid color coating,
It is useful for clear paints and base coat paints. In particular, the low solvent type coating composition of the present invention is particularly excellent as a clear coating or an intermediate coating. Further, the low-solvent type coating composition of the present invention can be sequentially applied as an intermediate coating composition, a base coating composition and a clear coating composition, or can be applied as a solid color coating composition and a clear coating composition. Furthermore, the low-solvent type coating composition of the present invention is used as an intermediate coating composition, and a base coat coating composition and a clear coating composition consisting of a conventionally known organic solvent-based coating composition or an aqueous coating composition are applied on the composition by wet-on-wet. be able to. Further, the low-solvent type coating composition of the present invention can be used as a base coat coating, and a conventionally known clear coating can be applied thereon. Further, a conventionally known base coat paint may be applied, and then a clear paint as the low solvent type paint composition of the present invention may be applied thereon by wet on wet. In this case, as the base coat paint,
For example, it is preferable to use a coating composition containing a melamine resin and an oligomer having a hydroxyl group and having a weight average molecular weight of 6000 or less. Such a base coat paint composition may be an organic solvent type paint or an aqueous paint. Further, the base coat coating composition preferably has a coating solid content of 35% by weight or more, particularly 40% by weight or more.

The low-solvent type coating composition of the present invention can reduce the viscosity of the coating composition although the amount of the organic solvent is small. That is, it is possible to maintain the viscosity suitable for coating, although the solid content of the coating can be significantly reduced as compared with the conventional case. For example, the amount of organic solvent can be 40% or less, preferably 35% or less, and particularly preferably 30% or less. The lower limit is 5%. In the application of the low solvent type coating composition of the present invention, even if it is applied thickly, sagging does not occur, and in order to improve the surface smoothness, it is applied while rotating the object to be coated around a horizontal axis. It is preferable. For example, as disclosed in Japanese Patent Laid-Open No. 63-178871, for example, an object to be coated such as a car body is fixed from a vertical direction and the body is rotated horizontally while the low solvent type of the present invention is used. Apply a coating composition,
Alternatively, even when baked or dried, the coating can be applied to a thickness equal to or greater than the limit thickness (threshold film thickness) at which sagging when stationary occurs. The rotation is preferably continuous rotation and has a large sagging prevention effect. More specifically, it is a method for coating the surface of an article to be coated with the low-solvent type coating composition of the present invention, in which a normal upper and lower surface of the article to be coated rotatably supported about a substantially horizontal axis is provided. On the surface extending in the direction, paint is applied to a film thickness that causes sagging, and then the sagging of the paint applied to the surface of the object is started to rotate about the horizontal axis before the sagging occurs due to gravity. , And the speed at which the surface of the object to be coated transitions from a substantially vertical state to a substantially horizontal state before at least the rotation of the applied coating is caused by gravity, Rotate at a slow speed.

The rotation speed is generally 0.2 to 120 rpm, preferably 5 to 20 rpm. When the rotation speed is less than 0.2 rpm, the effect of preventing sagging is small, which is not preferable. On the other hand, if it is higher than 120 rpm, conversely, sagging tends to occur due to centrifugal force, which is not preferable. Note that, for example, they may be reversed in the order of 90 ° → 135 ° → 160 °. In this way, after coating while rotating the object to be coated around the horizontal axis, while maintaining its rotation, the paint is set vertically (usually without a heating device) or baked (with a heating device). Meanwhile, a coating film is formed by moving the object to be coated. The set (dry) is
Generally 5 to 30 minutes, preferably 5 to 15 minutes, at room or ambient temperature. The baking is performed at 60 to 200 ° C., preferably 80 to 160 ° C. for 1 to 60 minutes, preferably 1
It is preferable to carry out for 0 to 40 minutes. The low solvent type coating composition of the present invention can be applied with a coating by hot spraying while further reducing the amount of solvent. Such a hot spray is, for example, a process from a tank storing a low solvent type coating composition to a step immediately before spraying at a predetermined temperature, generally 30 to 80 ° C., preferably 35.
It can be carried out by keeping the temperature at 70 ° C.

In the low solvent type coating composition of the present invention,
The characteristics of the coating film to be formed, for example, various characteristics such as gasoline resistance, chipping resistance, acid resistance, water resistance, and the appearance of the coating film are excellent, and the amount of organic solvent is Can also be much lower. For example, the amount of organic solvent is 40% or less, preferably 3
It can be reduced to 5% or less, more preferably 30% or less. Therefore, the problem of environmental pollution due to the release of the organic solvent can be significantly reduced.

[0070]

EXAMPLES The present invention will be described in more detail with reference to synthesis examples, reference examples, applied examples, etc., but the scope of the present invention is not limited by these examples. In addition,
In the following, parts and% are by weight unless otherwise specified.

[0071]

[Synthesis example] 1. Vinyl polymerization oligo containing hydroxyl group or blocked hydroxyl group
Synthesis of Mer's Synthetic Vinyl Polymerization Oligomers A-1 to A-24 In a four-necked flask equipped with a stirrer, a thermometer, an inert gas inlet and a dropping device, as shown in Table 1 below,
200 parts of xylene was charged and the temperature was raised to 140 ° C.
Then, as shown in Table 1, Praxel FM-1, 61
Parts, styrene, 24 parts, n-butyl acrylate, 15 parts, lauryl methacrylate, 10 parts and perbutyl-O (peroxide, manufactured by NOF CORPORATION), 8 parts were added dropwise over 3 hours, and further 6 hours. React to react with vinyl polymerization oligomer A
A solution of -1 was prepared. The oligomer A-1 was adjusted to the solid content shown in Table 1 by distilling off xylene under reduced pressure. Similarly, vinyl polymerized oligomers A-2 to 24 were prepared according to the raw material composition shown in Table 1. The characteristics of the obtained vinyl polymerized oligomer are shown in Table 1. In addition, since A-10 has a number average molecular weight and a weight average molecular weight of greater than 3000 and 6000, respectively,
Since -18 has a number average molecular weight of less than 700, A-
Since 19 has a weight average molecular weight of more than 6000,
-22 because the amount of functional groups is greater than 5, and A-
No. 24 is a reference example because the amount of functional groups is less than 1.5.

[0072]

[Table 1] Table 1 Vinyl polymerization oligomer A-1 A-2 A-3 A-4 A-5 A-6 A-7 Characteristic solid content% 100 70 100 100 180 100 90 Number average molecular weight (Mn) 1300 2700 800 1200 2500 920 1100 Weight average molecular weight (Mw) 2300 5700 1500 2500 5300 1750 2700 Functional group amount (mol / kg resin) OH group * 2.5 1.8 3.2 1.5 BOH group * 2.5 1.8 3.2 1.0 Si group * Raw material mixed xylene 200 150 250 200 200 200 200 Praxel FM-1 61 43.9 78 36.6 (Daicel Chemical Industries) Trimethylsiloxy 50.2 64.3 20.1 Ethyl methacrylate Monomer A * 38.7 Styrene 24 30 17 20 26.3 13.7 13.3 n-Butyl acrylate 5 16.1 19.8 25 12 20 A-187 * ( Nippon Yunika) Lauryl methacrylate 10 10 5 10 10 10 10 Perbutyl O 8 4 10 8 10 8 Azobisisobutyl 4 Nitrile Azobisvaleronitrile 5 Note) The OH group represents a hydroxyl group. The BOH group represents a blocked hydroxyl group. The Si group represents a hydrolyzable silyl group. Monomer A is 1-methyl-2-ethoxy-isopropoxyethyl methacrylate represented by the following formula.

[0073]

[Chemical 25] A-187 is 3-trimethoxysilylpropyl methacrylate represented by the following formula.

[0074]

[Chemical formula 26]

[0075]

[Table 2]

[0076]

[Table 3] Table 1 (continued) Vinyl polymerized oligomer A-11 A-12 A-13 A-14 A-15 A-16 A-17 Characteristics Solid content 80 70 100 80 70 100 80 Number average molecular weight (Mn) 1500 2600 1100 1300 2200 1000 1300 Weight average molecular weight (Mw) 3300 5800 2000 2700 4600 1800 2500 Functional group amount (mol / kg resin) OH group 2.5 1.8 3.2 1.5 BOH group 2.5 1.8 3.2 1.0 Raw material mixed xylene 200 150 200 200 150 200 200 Praxel FM-1 61 43.9 78 36.6 Trimethylsiloxy 50.2 64.3 20.1 Ethyl methacrylate Monomer A 38.7 Styrene 24 30 17 20 26.3 13.7 13.3 Butyl acrylate 15 26.1 5 29.8 35 22 22 Perbutyl O 7 4 9 8 9 7 Azobisisobutyro 4 Nitrile Azobisvaleronitrile 5

[0077]

[Table 4] Table 1 (continued) Vinyl polymerized oligomer A-18 A-19 A-20 A-21 A-22 A-23 A-24 Characteristic solid content% 100 70 70 100 70 70 90 Number average molecular weight (Mn) 500 2500 3500 800 2500 3700 1000 Weight average molecular weight (Mw) 1200 6500 1300 1700 5500 7800 2500 Functional group amount (mol / kg resin) OH group 2 2 2.5 1.2 6 2 1 BOH group raw material blended xylene 300 150 100 250 150 100 200 Praxel FM-1 48.8 48.8 61 29 Styrene 31.2 31.2 25 40 10 40 40 Butyl acrylate 20 20 14 31 12 20 40 2-Hydroxyethyl 78 methacrylate Trimethylsiloxy 40 20 Ethyl methacrylate Perbutyl O 12 4 0.6 10 2 0.5 10 2. Polyester ori containing hydroxyl groups or blocked hydroxyl groups
Gomer's synthetic polyester oligomers P-1 to P-8 were synthesized in a four-necked flask equipped with a stirrer, an inert gas inlet, a dropping funnel, and a thermometer. Put in 10
The temperature was raised to 0 ° C. Next, 100 parts of succinic anhydride was added dropwise over 5 minutes, and then the mixture was reacted at 100 ° C for 1 hour. Then, a mixed solution of 684 parts of ε-caprolactone and 0.1 part of tetrabutyl titanate was added dropwise over 10 minutes, and then a further 15
The reaction was carried out at 0 ° C for 8 hours. Then, a mixed solution of 130 parts of butyl glycidyl ether and 1 part of dimethylimidazole was added dropwise over 10 minutes, and the reaction was continued for 6 hours at that temperature to complete the synthesis, and the solvent-free polyester oligomer P
-1 was obtained. Similarly, polyester oligomers P-2 to 8 were synthesized based on the raw material composition shown in Table 1 below (P-4 and P-5 were synthesized in xylene. That is, 1000 parts of xylene was mixed with pentaerythritol. I prepared it.). Obtained polyester oligomers P-1 to 8
Table 2 also shows the characteristics of.

[0078]

[Table 5] Table 2 Polyester oligomer P-1 P-2 P-3 P-4 P-5 Characteristics Solid content (%) 100 80 100 80 70 Number average molecular weight (Mn) 1100 2050 850 2700 2900 Weight average molecular weight (Mw ) 1300 2450 970 3300 4200 functional group content (mol / kg resin) OH groups 3.8 2.0 3.6 1.5 2.1 material blending trimethylolpropane 134 134 pentaerythritol 136 136 136 .epsilon.-caprolactone 684 456 342 butyl glycidyl 130 390 ether succinic anhydride 100 400 300 Cardura E10 1000 (Yuka shell) .epsilon.-caprolactone 456 tetrabutyl titanate 0.1 0.1 0.1 0.1 1-methylimidazole 1 1 1 1 1 phthalic anhydride 592 Cardura E10 1000 .epsilon.-caprolactone 456 trimellitic anhydride 572 Cardura E10 1500 .epsilon. Caprolactone 1342

[0079]

[Table 6] Table 2 (continued)

Preparation of paint 1. Preparation of intermediate coating material (1) Preparation of intermediate coating material raw materials Using the above oligomers, intermediate coating materials N1 to N5 and HN1 to 5 (HN series are comparative coating materials) according to the raw material formulations shown in Tables 3 and 4 (comparative coating materials) below. Was prepared). (2) Preparation of intermediate coating material The prepared intermediate coating material raw materials N1 to 5 and HN1 to 5 were dissolved in Solvesso 100 (manufactured by Exxon) / cyclohexane (8 /
In 2), it was diluted with Ford Cup No. 4 (25 ° C) for 25 seconds. 2. Preparation of Solid Color Paint (1) Preparation of Solid Color Paint Raw Material Using the above oligomers, solid color paint raw materials S1 to 5 and HS1 to 5 (HS) according to the raw material composition shown in Table 5 and Table 6 (Comparative paint) below. Series are comparative paints). (2) Preparation of solid color paint
(Manufactured by Exxon) / cyclohexane (8/2) and diluted with Ford cup No. 4 (25 ° C.) for 25 seconds. 3. Preparation of clear coating material (1) Preparation of clear coating material Using the above oligomers, clear coating materials C1 to C1
12 and HC1-9 (HC series is a comparative paint)
Was prepared. (2) Preparation of clear coating material Prepared clear coating material C1-12 and HC1-9
Was diluted with Solvesso 100 (manufactured by Exxon) using Ford cup No. 4 (25 ° C.) for 25 seconds.

4. Preparation of base coat paint (1) Preparation of base coat paint raw materials Using the above oligomers, the base coat paint raw materials B1 to 7 and HB1 to 4 (HB series are compared according to the raw material composition shown in Table 9 and Table 10 (Comparative paint) below. Paint) was prepared. (2) Preparation of base coat paints Prepared base coat paint raw materials B1 to 7 and HB1 to 4
Was diluted with toluene / methyl ethyl ketone (7/3) in Ford cup No. 4 (25 ° C.) for 14 seconds.

Confirmation of paint performance (1) Intermediate coating material The intermediate coating material prepared above was applied to the electrodeposition plate using a wiper 77 as a coating gun so that the film thickness after drying was 30 μm, and the coating temperature was 140 ° C. It was baked for 30 minutes. After coating OTO520-1 (Silver base coat made by Nippon Paint Co., Ltd.) on it so that the film thickness after drying becomes 15 μm, the film thickness after drying OTO563 clear paint (Nippon Paint Co., Ltd.) becomes 30 μm. And then baked at 140 ° C. for 30 minutes. (2) Solid color paint OTO850 (manufactured by Nippon Paint Co., Ltd.) is coated on the electrodeposition plate and baked at 140 ° C. for 30 minutes, and then the solid color paint prepared above is used by using a wiper 77 as a coating gun. It was coated so that the film thickness after drying would be 30 μm, and baked at 140 ° C. for 30 minutes. (3) Clear paint OTO850 (manufactured by Nippon Paint Co., Ltd.) was applied on the electrodeposition plate so that the film thickness after drying would be 30 μm, and the temperature was maintained at 140 ° C. for 30 minutes.
It was baked for minutes. Then, OTO520-1 (Silver base coat made by Nippon Paint Co., Ltd.) was coated on it so that the film thickness after drying would be 15 μm, and after setting for 10 minutes,
The thickness of the clear coating prepared above is 30μm after drying.
And was baked at 140 ° C. for 30 minutes. (4) Base coat paint OTO850 (manufactured by Nippon Paint Co., Ltd.) was coated on the electrodeposition plate so that the film thickness after drying would be 30 μm, and the temperature was maintained at 140 ° C. for 30 minutes.
It was baked for minutes. Then, the base coat paint prepared above is applied on it using a wiper 77 so that the film thickness after drying becomes 30 μm, and after setting for 10 minutes,
After coating OTO563 clear paint (Nippon Paint Co., Ltd.) to a film thickness of 30 μm after drying, 140
Baked at 30 ° C for 30 minutes.

[0083]Performance evaluation method (1) Water resistance test Each coated plate was immersed in warm water at 60 ° C for 10 days and cross-cut.
A tape peeling test (adhesion test) was performed. Water resistance test
In ◎, if there is no peeling of paint, ◎, peeling is 5 in area
Those with less than 5% were evaluated as ◯, and those with 5% or more were evaluated as x. (2) Adhesion test Put a cross cut on each coated plate with a knife and put it in the
Adhesion test by sticking and peeling
Was. In this test, the one that showed adhesiveness is ○,
Those that are not marked with x. (3) Thermal cycle test After putting a cross-cut on each coated plate with a knife,
Time, 1 hour at room temperature, 1 hour at -20 ° C, 1 hour at room temperature
10 cycles are repeated with 1 cycle as
The occurrence was confirmed. In this test,
Those that did not occur were indicated as ○, and those that did not occur were indicated as ×. (4) Coating solid content Limitable to coat with hot spray at 25 ℃ and 60 ℃
The solvent content (%) in field viscosity was measured. Where the solvent
◎ if the content is 15% or less and paintable
◯: paintable at 30% or less, 40% or more from 30%
The ones that can be painted below are marked with △, and those with more than 40% are marked with ×.
Was displayed. (5) Chipping resistance Each coated plate is placed in a diamond shot tester at an angle of 20 °.
And then add 0.02 g of diamond to 200 at -20 ° C.
Collision at a speed of km / H and the peeling area (mm²)
It was measured. Where the peeling area is 1 mm²◎,
1 mm²2 mm or more ²Less than ○, 2 mm²3 mm or more²Not yet
Full of △ △ 3mm²The above is indicated by x. (6) Weather resistance The gloss of the coating film after being subjected to an accelerated weather resistance tester for 3000 hours.
The retention rate was measured. Here, the gloss retention rate is 85% or more.
◎, 70% or more and less than 85% ○, 70% not
The thing of fullness was expressed by X. (7) Acid resistance pH 3% H₂SO_FourAdd 0.2 ml of the aqueous solution dropwise
Then, after drying for 30 minutes at 40 ℃, the coating film
If there is no trace of etching, etching, etc.,
Those with such traces were marked with x. (8) Gasoline resistance Tilt the coated plate at 45 ° and put gasoline (Nisseki Silva
1) was poured and left to dry. This one cycle
After 10 cycles of the
Observed at. Here, those that do not change are ○, discoloration and class
The occurrence of the crack was marked as x.

[0084]

[Table 7] Table 3 Medium coating N1 N2 N3 N4 N5 Taipaque CR-95 50 50 80 70 100 (Ishihara Sangyo) P-1 50 P-2 50 P-3 50 P-4 50 P-5 50 Celoxide 2021 23.9 30 75.6 141 (Daicel Chemical Industries) Celoxide 2081 65.9 (Daicel Chemical Industries) Celoxide 2083 37 (Daicel Chemical Industries) San-Aid SIL100 2 3 (Sanshin Chemical) Trimethoxyphenyl 2 2 Silane Trisacetylacetonato 2 2 3 Aluminum A-10 5 A-11 Bigetol OK 1 1 1 1 1 1 (Big Chemie Japan) KP321 (Shin-Etsu Chemical) Tinuvin 384 (Ciba Geigy) Sandbar 3058 (Sand) A-14 A-17 Oligomer / alicyclic epo 1/1 1/3 1/2 1/10 1/17 alkoxy group-containing compound film properties chipping resistance ◎ ◎ ○ ◎ ◎ water resistance ○ ○ ○ ○ ○ thermal cyclability ○ ○ ○ ○ ○ paint solids 25 ℃ ◎ ◎ ○ ◎ ◎ 60 ℃ ◎ ◎ ◎ ◎

[0085]

[Table 8] Table 4 Comparative intermediate coating paint HN-1 HN-2 HN-3 HN-4 HN-5 Taipaque CR95 50 50 100 50 300 P-6 50 P-7 50 P-8 50 P-1 50 50 Celoxide 2021 42 24 550 Celoxide 2083 21 73 Viketol OK 1 1 1 1 1 (Big Chemie Japan) San-Aid SLI100 3 3 3 3 5 KP321 Tinuvin 384 (Ciba Geigy) Sandbar 3058 (Sand) Oligomer / alicyclic epo 1/1 1/1 1 / 5 1 / 0.5 1/23 Xy group-containing compound Coating film characteristics Chipping resistance × ○ ○ ○ × Water resistance × ○ × ○ ○ Heat cycle property × ○ × ○ ○ Coating solid content 25 ° C ◎ × ◎ × ◎ 60 ° C ◎ △ ◎ ○ ◎

[0086]

[Table 9] Table 5 Solid color paint S1 S2 S3 S4 S5 S6 S7 S8 Taipaque CR-95 50 50 80 70 100 50 100 100 P-1 50 P-2 50 P-3 50 P-4 50 P-5 50 Celoxide 2021 23.9 30 45 75.6 157 38.8 50.4 50.9 Celoxide 2081 18.3 Celoxide 2083 San-Aid SIL 100 2 3 2 3 Trimethoxyphenyl 22 2 Silane Trisacetylacetonato 2 2 3 Aluminum A-10 5 A-11 50 Viketol OK KP 321 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 Tinuvin 384 1 1 1 1 1 1 1 1 Sandbar 3058 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 A-14 50 A-17 50 Oligomer / alicyclic epo 1/1 1/3 1/2 1/10 1 / 11 1/3 1/4 1/5 Xy group-containing compound Coating film characteristics Water resistance ◎ ○ ○ ○ ○ ○ ○ ○ Acid resistance ○ ○ ○ ○ ○ ○ ○ ○ Weather resistance ○ ○ ○ ○ ○ ○ ○ ○ Solid content 25 ℃ ◎ ◎ ◎ ◎ ◎ ◎ ○ ◎ ◎ 60 ℃ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ Gasoline resistance ○ ○ ○ ○ ○ ○ ○ ○

[0087]

[Table 10] Table 6 Comparative solid color paints HS-1 HS-2 HS-3 HS-4 HS-5 Typepaque CR95 50 50 50 50 300 P-6 50 P-7 50 P-8 50 P-1 50 50 Celoxide 2021 42 24 550 Celoxide 2083 21 73 Biquetol OK 1 1 1 Sun-Aid SLI100 3 3 3 3 5 KP321 0.01 0.01 0.01 0.01 0.01 Tinuvin 384 1 1 1 1 1 Sandbar 3058 0.5 0.5 0.5 0.5 0.5 Oligomer / Resin Epo 1/1 1/1 1/5 1 / 0.5 1/23 Xy group-containing compound Coating film characteristics Acid resistance ○ ○ ○ ○ ○ Water resistance ○ ○ ○ ○ ○ Gasoline resistance × ○ × ○ ○ Weather resistance × ○ ○ ○ × Coating solid content 25 ℃ ◎ × ◎ × ◎ 60 ℃ ◎ △ ◎ ○ ◎

[0088]

[Table 11] Table 7 Clear paint C1 C2 C3 C4 C5 C6 C7 C8 A-1 100 A-2 100 A-3 100 A-4 100 A-5 100 A-6 100 A-7 100 A-8 100 A- 9 A-10 Celoxide 2021 31.5 190 32.2 156 91 121 283 32 Celoxide 2081 26.4 San-Aid SLI100 3 5 7 Tomelitoxy 3 5 7 3 Phenylsilane Trisacetylaceto 3 5 7 3 3 Natoaluminum KP321 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Tinuvin 384 2 5 2 5 5 5 2 2 Sandbar 3058 1 2 1 2 2 2 1 1 Oligomer / alicyclic Epo 1/1 1/12 1 / 0.8 1/5 1/6 1/3 1/10 1/2 Xy group included Compound coating properties Water resistance ○ ○ ○ ○ ○ ○ ○ ○ Acid resistance ○ ○ ○ ○ ○ ○ ○ ○ Weather resistance ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ Coating solid content 25 ℃ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ○ 60 ℃ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ Gasoline resistance ○ ○ ○ ○ ○ ○ ○ ○ ○

[0089]

[Table 12] Table 7 (continued)

[0090]

[Table 13] Table 8Comparative clear paint HC1 HC2 HC3 HC4 HC5 HC6 HC7 HC8 HC9 A-18 100 A-19 100 A-20 100 A-21 100 A-22 100 A-23 100 A-24 100 A-3 100 A-2 100 Celoxide 2021 25 64 16 105 34 8 1008 Celoxide 2083 83 84 Sun Aid SIL100 2 4 3 2 4 4 2 4 10 KP321 0.05 0.05 0.05 0.05 0.1 0.05 0.05 0.05 0.5 Tinuvin 384 2 3 3 2 4 4 2 2 10 Sandbar 3058 1 1 1 1 2 2 1 1 5 Oligomer / alicyclic Epo 1/1 1/2 1/2 1/1 1/2 1/2 1/3 1 / 0.5 1/25 Xy group-containing compound Coating properties Acid resistance ○ ○ ○ ○ ○ ○ ○ ○ ○ Water resistance ○ ○ ○ ○ ○ ○ ○ ○ ○ Gasoline resistance × ○ ○ × ○ ○ × ○ ○ Weather resistance × ○ ○ × ○ ○ × ○ × Paint solids 25 ℃ ◎ × × ◎ × × ◎ × ◎ 60 ° C ◎ △ ○ ◎ △ △ ◎ △ ◎

[0091]

[Table 14] Table 9 Base coat paint B-1 B-2 B-3 B-4 B-5 B-6 B-7 FR-606C 10 10 10 10 10 10 10 (Asahi Kasei) Toluene 10 10 10 10 10 10 10 A-2 A-3 A-11 50 A-12 50 A-13 50 A-14 50 A-15 50 A-16 50 A-17 50 A-18 A-19 Celoxide 2081 9.2 57 18.3 Celoxide 2021 6.3 126 40 40 38 MG-100 5 5 5 5 5 5 5 (Dainippon Ink and Chemicals) Tinuvin 384 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Sandbar 3058 0.2 0.2 0.2 0.2 0.2 0.2 0.2 KP321 0.01 0.01 0.01 0.01 0.01 0.01 0.01 Sun Aid SIL 100 3 5 7 5 Trimethoxy 3 3 3 Phenylsilane Trisacetylaceto 3 3 3 Natoaluminium Celoxide 2083 Oligomer / alicyclic Epo 1/1 1/5 1/2 1/1 1/5 1/2 1/3 Xy group-containing compound coating Characteristics Chipping resistance ◎ ◎ ◎ ○ ○ ○ ◎ Water resistance ○ ○ ○ ○ ○ ○ ○ Thermal cycle resistance ○ ○ ○ ○ ○ ○ ○ Paint solids 25 ℃ △ △ ◎ △ ◎ ◎ ◎ ◎ 60 ℃ ○ ○ ◎ ○ ◎ ◎ ◎ ◎ Gasoline resistance ○ ○ ○ ○ ○ ○ ○

[0092]

[Table 15] Table 10 Comparative base coat paint HB-1 HB-2 HB-3 HB-4 FR-606C 10 10 10 10 Toluene 10 10 10 10 A-2 50 A-3 5 A-18 50 A-19 50 Celoxide 2021 12.5 4 50 MG-100 5 5 5 5 Tinuvin 384 0.5 0.5 0.5 0.5 Sandbar 3058 0.2 0.2 0.2 0.2 KP321 0.01 0.01 0.01 0.01 Sun-Aid SLI100 3 3 3 3 Celoxide 2023 42 Oligomer / Resin Epo 1/1 1/2 1 / 0.5 1/25 Xy group-containing compound Coating film characteristics Chipping resistance × ○ ○ × Water resistance × ○ ○ ○ Heat cycle property ○ ○ ○ ○ Coating solid content 25 ° C ◎ × × ◎ 60 ° C ◎ △ △ ◎ Gasoline resistance × ○ ○ ×

[0093]

As can be seen from the above data, the coating composition of the present invention has excellent chipping resistance, water resistance, gasoline resistance, weather resistance, acid resistance, and further,
It is possible to form a coating film having excellent coating film characteristics such as thick film property, and it is possible to significantly reduce the amount of organic solvent used.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Kubota 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Motor Corporation

Claims (4)

[Claims] (1) 1.5-5.0 mol / kg of a resin containing a hydroxyl group and / or a blocked hydroxyl group and having a number average molecular weight of 7
0 to 3000 and a weight average molecular weight of 700 to 60
00, and (2) an alicyclic epoxy group-containing compound having a plurality of alicyclic epoxy groups in one molecule and having a molecular weight of 230 to 800, the oligomer / the alicyclic group A low-solvent type resin composition characterized in that the epoxy group compound has a molar ratio of 1 / 0.7 to 1/20 and an organic solvent amount of 5 to 40%. (1) A hydroxyl group and / or a blocked hydroxyl group of 1.5-5.0 mol / kg resin is contained, and the number average molecular weight is 7
0 to 3000 and a weight average molecular weight of 700 to 60
00, an alicyclic epoxy group-containing compound having a plurality of alicyclic epoxy groups in one molecule and having a molecular weight of 230 to 800, and (3) a cationic polymerization catalyst. , The molar ratio of the oligomer / the alicyclic epoxy group compound is 1 / 0.7 to 1
/ 20 and the amount of organic solvent is 5 to 40%, which is a low solvent type coating composition. 3. A coating which comprises coating the surface of an article to be coated with the low solvent type coating composition according to claim 2 and then thermally curing the composition to form a coating film on the surface of the article. Method. 4. A method for coating the surface of an article to be coated with the low solvent type coating composition according to claim 2, wherein the surface of the article to be coated is rotatably supported about a substantially horizontal axis. On the surface that normally extends in the vertical direction, apply paint to a film thickness that causes sagging,
Then, before the sagging of the paint applied to the surface of the object to be coated is caused by gravity, the object to be coated is started to rotate about a substantially horizontal axis, and the rotation is at least before the sagging of the applied material is caused by the force of gravity. In addition, the coating method is characterized in that the surface of the article to be coated is rotated at a speed at which the surface changes from a substantially vertical state to a substantially horizontal state and at a speed slower than the speed at which the coating sags due to the centrifugal force due to the rotation.