JP7078331B2 - Paint composition - Google Patents

Description

The present invention relates to a coating composition capable of forming a coating film having excellent chipping resistance, adhesiveness, and gasoline resistance.

Generally, an automobile body has a metal material that forms a body and a plastic material that forms a bumper or the like. Since the polarities of metal materials and plastic materials are completely different, paints for metal materials do not easily adhere to plastic materials, and automobile bodies usually have separate undercoat paints (also called primer paints) for metal materials and plastic materials. It is painted.

However, if the metal material and the plastic material can be painted with the same undercoat paint, cost reduction can be expected in the manufacture of automobile bodies.

As a method for improving the adhesion to metal materials and plastic materials, for example, Patent Document 1 describes (A) a styrene / isoprene block copolymer or a hydrogenated product thereof, a monoolefin dicarboxylic acid and its anhydride, and a mono. A modified copolymer obtained by graft-copolymerizing at least one modified monomer selected from a monoalkyl ester of an olefin dicarboxylic acid so as to contain 0.05 to 20% by weight, (B) a polyester resin, and (C). A primer composition comprising an organic solvent is disclosed.

However, the primer composition disclosed in Patent Document 1 is resistant to gasoline and the chipping phenomenon in which the coating film is peeled off due to the collision of pebbles with the coated surface of the outer panel of the automobile body, that is, the chipping resistance. It was not considered.

Further, Patent Document 2 describes at least one modified single amount selected from a monoolefin dicarboxylic acid and its anhydride, and a monoalkyl ester of the monoolefin dicarboxylic acid in a styrene / isoprene block copolymer or a hydrogenated product thereof. It is characterized by containing a modified graft copolymer (A) and an organic solvent (B), which are obtained by adding a monoepoxy compound (b) to a graft copolymer (a) obtained by graft-copolymerizing a body, as main components. The coating composition to be used is disclosed.

However, the coating composition disclosed in Patent Document 2 does not consider gasoline resistance.

Japanese Unexamined Patent Publication No. 6-5702 Japanese Unexamined Patent Publication No. 6-57201

The present invention has been made in consideration of these points, and provides a coating composition capable of forming a coating film having excellent chipping resistance, adhesiveness, and gasoline resistance with respect to metal materials and plastic materials. The purpose is.

As a result of diligent studies to achieve the above object, the present inventors have obtained chlorinated and / or non-chlorinated polyolefin (A), acrylic-modified styrene-based thermoplastic elastomer (B), epoxy resin (C), and the like. It has been found that the above problems can be solved by using a coating composition containing the blocked polyisocyanate compound (D) and the pigment (E), and the present invention has been completed.

That is, the present invention provides the following coating composition.
Item 1.
A coating composition comprising a chlorinated and / or non-chlorinated polyolefin (A), an acrylic modified styrene-based thermoplastic elastomer (B), an epoxy resin (C), a blocked polyisocyanate compound (D), and a pigment (E).
Item 2.
The acrylic-modified styrene-based thermoplastic elastomer (B) includes an acrylic portion and a styrene-based thermoplastic elastomer portion.
The glass transition temperature of the acrylic portion of the acrylic-modified styrene-based thermoplastic elastomer (B) is 20 to 100 ° C., and the solid content mass ratio between the acrylic portion and the styrene-based thermoplastic elastomer portion is 5: 5 to 9. Item 1. The coating composition according to Item 1, wherein the ratio is 1.
Item 3.
Item 2. The coating composition according to Item 1 or 2, wherein the epoxy resin (C) is a polysulfide-modified epoxy resin (C1).
Item 4.
Item 6. The coating composition according to any one of Items 1 to 3, wherein the blocked polyisocyanate compound (D) is an active methylene-based blocked polyisocyanate compound.
Item 5.
A coating method comprising coating an object to be coated with the coating composition according to any one of Items 1 to 4, and then applying a topcoat coating material to the coated surface.
Item 6.
The coating composition according to any one of Items 1 to 4 is applied to the object to be coated, a base coat paint is applied on the uncured coated surface, and a clear coat paint is further applied on the uncured coated surface. A painting method that involves painting and curing.

According to the coating composition of the present invention, a coating film having excellent chipping resistance, adhesiveness, and gasoline resistance is formed for both metal and plastic materials without using a special primer. It becomes possible.

Hereinafter, the coating composition of the present invention will be described in more detail.

The coating composition of the present invention comprises a chlorinated and / or non-chlorinated polyolefin (A), an acrylic modified styrene-based thermoplastic elastomer (B), an epoxy resin (C), a blocked polyisocyanate compound (D), and a pigment (E). ) Is included.

Chlorinated and / or non-chlorinated polyolefin (A)
In the present invention, the chlorinated and / or non-chlorinated polyolefin (A) includes chlorinated polyolefin (A1), non-chlorinated polyolefin (A2), acrylic-modified chlorinated polyolefin (A3) and acrylic-modified non-chlorinated polyolefin (A4). ) Are included, and these can be used alone or in combination of two or more.

The chlorinated polyolefin resin (A1) is a chlorinated polyolefin, and the base polyolefin is, for example, a radical homopolymer of at least one olefin selected from ethylene, propylene, butene, methylbutene, isoprene and the like. Alternatively, examples thereof include copolymers and radical copolymers of the olefins with vinyl acetate, butadiene and the like. The chlorinated polyolefin can generally have a weight average molecular weight in the range of about 30,000 to 200,000, particularly about 50,000 to 150,000.

The chlorine content of the chlorinated polyolefin resin (A1) is in the range of about 10 to 40% by weight. When the chlorine content is within this range, the solubility in the solvent does not decrease, so that atomization during spray coating is sufficient, and the solvent resistance of the coating film does not decrease. The chlorine content is preferably in the range of about 12 to 35% by weight.

As the chlorinated polyolefin resin (A1), chlorinated polyethylene, chlorinated polypropylene, chlorinated ethylene-propylene copolymer, chlorinated ethylene-vinyl acetate copolymer and the like are preferable.

The chlorinated polyolefin resin (A1) may be acid-modified. Examples of the acid-modified chlorinated polyolefin include unsaturated carboxylic acids (preferably unsaturated mono- or di-carboxylic acids) such as maleic acid, fumaric acid, itaconic acid, and (meth) acrylic acid, or anhydrous of these unsaturated carboxylic acids. Those obtained by graft-polymerizing using a substance according to a method known per se can be used, and those modified with maleic anhydride are particularly preferable.

When the chlorinated polyolefin (A1) is used in the coating composition of the present invention, the content thereof is 5 to 50% by mass, preferably 10 to 30% by mass based on the total resin solid content in the coating composition. More preferably, it is 12 to 25% by mass, which is preferable from the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the obtained coating film.

As the non-chlorinated polyolefin resin (A2), for example, at least one olefin selected from olefins having 2 to 10 carbon atoms, particularly 2 to 4 carbon atoms, such as ethylene, propylene, butylene, hexene, octene, and decene () Co) A polyolefin obtained by polymerization, or an unsaturated carboxylic acid (preferably unsaturated mono- or di-carboxylic acid) such as maleic acid, fumaric acid, itaconic acid, (meth) acrylic acid, or these. Those obtained by graft polymerization using an anhydride of unsaturated carboxylic acid according to a method known per se can be used, and those modified with maleic anhydride are particularly preferable. Further, the unsaturated carboxylic acid or acid anhydride-modified polyolefin may be amine-modified or alcohol-modified. As the amine and alcohol, known ones can be used alone or in combination of two or more.

When the non-chlorinated polyolefin resin (A2) is used in the primer coating composition of the present invention, the content thereof is 5 to 50% by mass, preferably 10 to 10 to 50% by mass based on the total resin solid content in the coating composition. 30% by mass, more preferably 12 to 25% by mass, is preferable from the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the obtained coating film.

The acrylic-modified chlorinated polyolefin (A3) is a chlorinated polyolefin modified with an acrylic resin, and contains an acrylic portion and a chlorinated polyolefin portion.

As a method for obtaining the acrylic-modified chlorinated polyolefin (A3), for example, α, β-unsaturated carboxylic acid and / or an acid anhydride thereof is graft-polymerized with the polyolefin to obtain an acid-modified polyolefin (a1), and then the acid-modified polyolefin (a1) is obtained. The acid-modified polyolefin (a1) is chlorinated to form an acid-modified chlorinated polyolefin (a2), and then a polymerizable unsaturated monomer containing a hydroxyl group-containing (meth) acrylic acid ester is graft-polymerized in the presence of a polymerization initiator. The acid-modified chlorinated polyolefin (a2) is reacted with a hydroxyl group-containing (meth) acrylic acid ester to esterify the acid-modified chlorinated polyolefin (a2), and a double bond is introduced into the acid-modified chlorinated polyolefin (a2) to double the acidity. After obtaining the bond-introduced chlorinated polyolefin, there is a method of graft-copolymerizing a polymerizable unsaturated monomer with the double-bond-introduced chlorinated polyolefin to modify the acid.

In addition, in this specification, "(meth) acrylate" means acrylate or methacrylate, and "(meth) acrylic acid" means acrylic acid or methacrylic acid.

As the polyolefin, for example, at least one olefin selected from olefins having 2 to 10 carbon atoms, particularly 2 to 4 carbon atoms such as ethylene, propylene, butylene, hexene, octene, and decene is (co) polymerized. Examples thereof include the obtained resin.

Examples of the α, β-unsaturated carboxylic acid and / or its acid anhydride include unsaturated carboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, and (meth) acrylic acid, or unsaturated carboxylic acids thereof. Among them, maleic acid and maleic anhydride are particularly preferable. These can be used alone or in combination of two or more.

Examples of the hydroxyl group-containing (meth) acrylic acid ester include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and polypropylene glycol (meth) acrylate. Examples thereof include (meth) acrylic acid esters having individual hydroxyl groups, and 2-hydroxyethyl (meth) acrylates are particularly preferable. These can be used alone or in combination of two or more.

Examples of the polymerizable unsaturated monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, and 2-ethylhexyl. Alkyl esters of (meth) acrylic acids such as (meth) acrylates, lauryl (meth) acrylates, stearyl (meth) acrylates; (meth) acrylic acids, glycidyl (meth) acrylates, 2-hydroxyethyl (meth) acrylates, (meth). ) Acrylic monomers such as acrylamide and (meth) acrylonitrile; further examples include styrene, and butyl (meth) acrylate, hexyl (meth) acrylate and cyclohexyl (meth) acrylate are particularly preferable. These can be used alone or in combination of two or more.

The graft copolymerization and esterification reactions can be carried out by methods known per se.

As the polymerization initiator, a peroxide-based initiator such as benzoyl peroxide or an azo-based initiator such as azobisisobutyronitrile can be preferably used.

In the present invention, the acrylic-modified chlorinated polyolefin (A3) has a glass transition temperature of the acrylic portion of 20 to 100 ° C., preferably 25 to 90, from the viewpoint of chipping resistance, adhesion, and gasoline resistance of the obtained coating film. ° C., more preferably 30 to 85 ° C., and the solid content mass ratio of the acrylic moiety to the chlorinated polyolefin moiety is 8: 2 to 2: 8, preferably 6.5: 3.5 to 2.5: 7. 5, more preferably 6: 4 to 3: 7 is preferable from the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the obtained coating film.

In the acrylic-modified chlorinated polyolefin (A3) and the acrylic-modified non-chlorinated polyolefin (A4), the glass transition temperature of the acrylic portion can be adjusted by the composition of the polymerizable unsaturated monomer.

In the present specification, the glass transition temperature Tg is a value calculated by the following formula.
1 / Tg (K) = W1 / T1 + W2 / T2 + ... Wn / Tn
Tg (° C) = Tg (K) -273
In the formula, W1, W2, ... Wn is the mass fraction of each monomer, and T1, T2 ... Tn is the glass transition temperature Tg (K) of the homopolymer of each monomer.
The glass transition temperature of the homopolymer of each monomer is determined by POLYMERHANDBOOKFourthEdition, J. Mol. Brandrup, E.I. h. Immunogut, E.I. A. The value according to Grulke ed. (1999), and the glass transition temperature of a monomer not described in the document is obtained by synthesizing a homopolymer of the monomer so that the weight average molecular weight is about 50,000, and the glass transition thereof. Use the value when the temperature is measured by differential scanning thermal analysis.

In the coating composition of the present invention, the content of the acrylic-modified chlorinated polyolefin (A3) is 5 to 50% by mass, preferably 10 to 30% by mass, more preferably 10 to 30% by mass, based on the total resin solid content in the coating composition. Is preferably 12 to 25% by mass from the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the obtained coating film.

The acrylic-modified non-chlorinated polyolefin (A4) is a non-chlorinated polyolefin modified with an acrylic resin, and contains an acrylic portion and a non-chlorinated polyolefin portion.

As a method for obtaining an acrylic-modified non-chlorinated polyolefin (A4), for example, after graft-polymerizing α, β-unsaturated carboxylic acid and / or an acid anhydride thereof with a polyolefin to obtain an acid-modified polyolefin (a1). , A method of graft-polymerizing a polymerizable unsaturated monomer containing a hydroxyl group-containing (meth) acrylic acid ester in the presence of a polymerization initiator to carry out acrylic modification, or a hydroxyl group-containing (meth) acrylic acid in the acid-modified polyolefin (a1). After the ester is reacted to esterify and a double bond is introduced into the acid-modified polyolefin (a1) to obtain a double bond-introduced polyolefin, a polymerizable unsaturated monomer is graft-copolymerized with the double-bond-introduced polyolefin. There are methods such as acrylic modification.

As the hydroxyl group-containing (meth) acrylic acid ester and the polymerizable unsaturated monomer, those listed in the item of the acrylic-modified chlorinated polyolefin (A3) can be used.

The graft copolymerization and esterification reaction can be carried out by the method described in the item of the acrylic modified chlorinated polyolefin (A3).

In the present invention, the acrylic-modified non-elemental polyolefin (A4) has a glass transition temperature of the acrylic portion of 20 to 100 ° C., preferably 25 to 25, from the viewpoint of chipping resistance, adhesion, and gasoline resistance of the obtained coating film. The temperature is 90 ° C., more preferably 30 to 85 ° C., and the solid content mass ratio between the acrylic portion and the non-chlorinated polyolefin portion is 7: 3 to 2: 8, preferably 6.5: 3.5 to 2.5 :. 7.5, more preferably 6: 4 to 3: 7, is preferable from the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the obtained coating film.

In the coating composition of the present invention, the content of the acrylic-modified non-elemental polyolefin (A4) is 5 to 50% by mass, preferably 10 to 30% by mass, more preferably 10 to 30% by mass, based on the total resin solid content in the coating composition. It is preferably 12 to 25% by mass from the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the obtained coating film.

Acrylic modified styrene-based thermoplastic elastomer (B)
In the present invention, known acrylic-modified styrene-based thermoplastic elastomers (B) can be used without limitation.
Including acrylic part and styrene-based thermoplastic elastomer part,
The glass transition temperature of the acrylic portion of the acrylic-modified styrene-based thermoplastic elastomer (B) is 20 to 100 ° C., preferably 25 to 90 ° C., more preferably 30 to 80 ° C., and the acrylic portion and the styrene-based heat. The solid content mass ratio with the thermoplastic elastomer portion is preferably 1: 9 to 9: 1, preferably 5: 5 to 8.7: 1.3, and more preferably 7: 3 to 8.5: 1.5. Suitable.

As a method for obtaining an acrylic-modified styrene-based thermoplastic elastomer (B), for example,
[I] A method of acrylic modification from a styrene-based thermoplastic elastomer (b1) by a hydrogen extraction reaction;
[II] A styrene-based thermoplastic elastomer (b3) having an acid group is obtained by graft-polymerizing an α, β-unsaturated carboxylic acid and / or an acid anhydride (b2) thereof on a styrene-based thermoplastic elastomer (b1). After that, a method of graft-copolymerizing a polymerizable unsaturated monomer in the presence of a polymerization initiator to modify the acrylic;
[III] A hydroxyl group-containing (meth) acrylic acid ester is reacted with the styrene-based thermoplastic elastomer (b3) having an acid group to esterify, and a double bond is introduced into the styrene-based thermoplastic elastomer (b3) having an acid group. After obtaining a double-bonded styrene-based thermoplastic elastomer (b4), a polymerizable unsaturated monomer is graft-copolymerized with the double-bonded-introduced styrene-based thermoplastic elastomer (b4) to perform acrylic modification;
And so on.

The acrylic modified styrene-based thermoplastic elastomer (B) can be used alone or in combination of two or more.

Examples of the styrene-based thermoplastic elastomer (b1) include a block and a random copolymer of styrene and an olefin and / or a conjugated diene: for example, a styrene-olefin and / or a conjugated diene block copolymer (styrene-olefin and / or a conjugated diene). Diblock copolymers, triblock copolymers, etc .; styrene-olefins and / or conjugated diene-styrene triblock copolymers, tetrablock copolymers, etc.), styrene-conjugated diene random copolymers, and these. Hydrogen additives, as well as mixtures of two or more of these.

Examples of the olefin constituting the copolymer include ethylene, propylene, 1-butene, 3-methyl-1-butene, 4-methyl-1-pentene and 3-methyl having 2 to 12 or more carbon atoms. -1-Pentene, 1-heptene, 1-hexene, 1-octene, 1-decene, 1-dodecene and other C4-C20 α-olefins alone or in combination of two or more, and as a conjugated diene, Examples thereof include those of C4 to C20, for example, butadiene, isoprene, and a combination system thereof.

Specific examples of the styrene-based thermoplastic elastomer (b1) include styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), and styrene-ethylene-ethylene-. Blocks of styrene and olefins such as propylene-styrene block copolymers (SEEPS) and random copolymers; styrene-isoprene-styrene block copolymers (SIS), styrene-butadiene-styrene block copolymers (SBS), Blocks and random copolymers of styrene and conjugated diene, such as random copolymers of styrene-butadiene; and hydrogenated additives of these copolymers [eg, hydrogenated SEBS, hydrogenated SBS, hydrogenated SIS]; and these. A mixture of two or more of the above can be mentioned. The styrene-based thermoplastic elastomer (b1) may be partially hydrogenated or completely hydrogenated.

In particular, in the present invention, the styrene-based thermoplastic elastomer (b1) is a styrene-ethylene-butylene-styrene block copolymer from the viewpoint of chipping resistance, adhesion, and gasoline resistance of the obtained coating film. (SEBS), especially hydrogenated SEBS, is preferred.

The method for preparing the hydrogenated additive of the styrene-based thermoplastic elastomer (b1) is not particularly limited and can be appropriately selected from known methods. For example, hydrogen gas is introduced in the presence of a so-called hydrogenated catalyst. The method etc. can be mentioned.

The styrene-based thermoplastic elastomer (b1) preferably has a styrene content of 10 to 50% by mass, particularly 15 to 45% by mass, based on the mass of the copolymer.

Further, the weight average molecular weight [polystyrene conversion value by gel permeation chromatography] (hereinafter abbreviated as Mw) is preferably in the range of 5,000 to 700,000, more preferably 5,000 to 300,000, particularly 10 000 to 200,000 is preferable.

The α, β-unsaturated carboxylic acid or its anhydride (b2) is usually added to the styrene-based thermoplastic elastomer (b1) by graft polymerization. Examples of the α, β-unsaturated carboxylic acid-based compound include (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, citraconic acid and their acid anhydrides, α, β-unreachable. Alkyl esterified products of saturated carboxylic acids, and the like. Specific examples of the alkyl esterified product of α, β-unsaturated carboxylic acid include maleic acid dialkyl esters such as maleic acid dimethyl ester and maleic acid diethyl ester; maleic acid monomethyl ester and maleic acid monoethyl ester such as maleic acid. Examples include acid monoalkyl esters. The α, β-unsaturated carboxylic acid or its anhydride (b2) can be used alone or in combination of two or more.

In particular, in the present invention, the α, β-unsaturated carboxylic acid or its anhydride (b2) is maleic acid or anhydrous from the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the obtained coating film. Maleic acid, itaconic acid, and itaconic anhydride are preferred.

The amount of α, β-unsaturated carboxylic acid or its anhydride (b2) used in the graft polymerization is 0.5 to 20% by mass, particularly 1 to 15% by mass, based on the mass of the styrene-based thermoplastic elastomer (b1). % Is preferable.

The styrene-based thermoplastic elastomer (b3) having an acid group has an acid value of 1 to 20 mgCH ₃ ONa / g, preferably 3 to 18 mgCH, from the viewpoint of chipping resistance, adhesion, and gasoline resistance of the obtained coating film. It is preferably ₃ ONa / g, more preferably 5 to 15 mgCH3ONa / g.

The styrene-based thermoplastic elastomer (b3) having an acid group is a styrene-ethylene-butylene-styrene copolymer having an acid group from the viewpoint of chipping resistance, adhesion, and gasoline resistance of the obtained coating film. Is preferable.

The styrene / (ethylene + butylene) ratio of the styrene-ethylene-butylene-styrene copolymer having an acid group is 5/95 to 50 from the viewpoint of chipping resistance, adhesion, and gasoline resistance of the obtained coating film. It is preferably / 50, preferably 7/93 to 45/55, and more preferably 10/90 to 40/60.

As the hydroxyl group-containing (meth) acrylic acid ester and the polymerizable unsaturated monomer that react with the styrene-based thermoplastic elastomer (b3) having an acid group, those listed in the item of the acrylic modified chlorinated polyolefin (A3) are used. be able to.

In the coating composition of the present invention, the content of the acrylic modified styrene-based thermoplastic elastomer (B) is 3 to 50% by mass, preferably 5 to 25% by mass, based on the total resin solid content in the coating composition. More preferably, it is 7 to 20% by mass, which is preferable from the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the obtained coating film.

Further, the coating composition of the present invention may be used in combination with a styrene-based thermoplastic elastomer other than the acrylic-modified styrene-based thermoplastic elastomer (B), if necessary. Examples of such a styrene-based thermoplastic elastomer include the styrene-based thermoplastic elastomer (b3) having an acid group.

Commercially available products of the styrene-based thermoplastic elastomer (b3) having an acid group include, for example, trade names "Tough Tech M1943", "Tough Tech M1913", "Tough Tech, M1911" manufactured by Asahi Kasei Corporation, and trade names manufactured by Kraton Polymer Japan Co., Ltd. Examples thereof include "KRATON FG1901G" and "KRATON FG1924G". These can be used alone or in combination of two or more.

In the coating composition of the present invention, the content of the component (b3) when the styrene-based thermoplastic elastomer (b3) having an acid group is used is 15 to 60 based on the total resin solid content in the coating composition. The mass%, preferably 20 to 55% by mass, and more preferably 25 to 50% by mass are preferable from the viewpoint of chipping resistance, adhesion, and gasoline resistance of the obtained coating film.

Epoxy resin (C)
In the present invention, as the epoxy resin (C), known ones can be used without limitation.

Examples of the epoxy resin include bisphenol A type epoxy resin; bisphenol F type epoxy resin; novolak type epoxy resin; hydrogenated bisphenol A type epoxy resin; ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and propylene. Glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane polyglycidyl ether, hexahydrophthalic acid diglycidyl ester, glycerin polyglycidyl ether, diglycerin An aliphatic type epoxy resin such as polyglycidyl ether and polyglycerin polyglycidyl ether; a biphenyl type epoxy resin; a dicyclopentadiene type epoxy resin; a polysulfide modified epoxy resin (C1); and the like can be mentioned. These can be used alone or in combination of two or more.

Further, the epoxy resin (C) has an epoxy equivalent of 110 to 500, preferably 130 to 350, and more preferably 150 to 250, from the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the formed coating film. It is preferable that it is within the range of.

Further, the epoxy resin (C) has a molecular weight in the range of 170 to 2,800, preferably 200 to 800, from the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the coating film to be formed. Is preferable. Further, the epoxy resin preferably has a hydroxyl group from the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the formed coating film.

In particular, it is preferable to use the polysulfide-modified epoxy resin (C1) from the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the obtained coating film.

The polysulfide-modified epoxy resin (C1) is a bisphenol type epoxy resin having an organic group containing a bisphenol skeleton and a polysulfide skeleton (—RS—S—) in the molecular backbone.

Examples of the organic group containing the bisphenol skeleton include bisphenol A type epoxy resin, bisphenol AD type epoxy resin, halogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, halogenated bisphenol F type epoxy resin and the like. .. Among them, the bisphenol F type epoxy resin is particularly suitable from the viewpoint of gasoline resistance and adhesiveness of the obtained coating film.

The polysulfide-modified epoxy resin (C1) has a number average molecular weight in the range of 110 to 4,500, preferably 900 to 3,500, and has an epoxy equivalent of 110 to 500 g / equivalent, preferably 130 to 400 g / equivalent. More preferably, it is preferable from the viewpoint of gasoline resistance and adhesiveness of the coating film obtained in the range of 150 to 350 g / equivalent.

The polysulfide-modified epoxy resin (C1) having a viscosity at 25 ° C. of 3000 poise or less, preferably 100 to 300 poise, is preferable from the viewpoint of ease of handling.

Commercially available products of the polysulfide-modified epoxy resin (C1) include "FLEP-10", "FLEP-50", "FLEP-60", "FLEP-65", "FLEP-80", "FLEP-120X", "FLEP-125X", and ". Examples thereof include FLEP-410C, FVD-103X, FVD-105X, and FVD-423C (trade names, all manufactured by Toray Fine Chemical Industries, Ltd.).

Examples of commercially available epoxy resins other than the polysulfide-modified epoxy resin (C1) include "jER827", "jER828", "jER828EL", "jER828XA", "jER834" (all manufactured by Japan Epoxy Resin), and " EPICLON840 "," EPICLON840-S "," EPICLON850 "," EPICLON850-S "," EPICLON850-CRP "," EPICLON850-LC "(all manufactured by DIC)," Epototo YD-127 "," Epototo YD-128 " (Above, manufactured by Toto Kasei Co., Ltd.), "Rica Resin BPO-20E", "Rica Resin BEO-60E" (above, manufactured by Shin Nihon Rika Co., Ltd.) and other bisphenol A type epoxy resins; "jER806", "jER807" (above, Bisphenol F type epoxy resin such as "EPICLON 830", "EPICLON 830-S", "EPICLON 835" (all manufactured by DIC), "Epototo YDF-170" (manufactured by Toto Kasei Co., Ltd.); "jER152" (Manufactured by Japan Epoxy Resin), etc. Novorak type epoxy resin; "jERYX8000", "jERYX8034" (above, manufactured by Japan Epoxy Resin), "Epototo ST-3000" (manufactured by Toto Kasei Co., Ltd.), "Rica Resin HBE-100" "(Shin Nihon Rika Co., Ltd.)" Denacol EX-252 "(above, Nagase Chemtex Co., Ltd.)," SR-HBA "(Sakamoto Yakuhin Kogyo Co., Ltd.), etc. , "YED216M", "YED216D" (all manufactured by Japan Epoxy Resin), "Epototo YH-300", "Epototo YH-301", "Epototo YH-315", "Epototo YH-324", "Epototo YH-" 325 ”(above, manufactured by Toto Kasei Co., Ltd.),“ Denacol EX-211 ”,“ Denacol EX-212 ”,“ Denacol EX-212L ”,“ Denacol EX-214L ”,“ Denacol EX-216L ”,“ Denacol EX- 313 ”,“ Denacol EX-314 ”,“ Denacol EX-321 ”,“ Denacol EX-321L ”,“ Denacol EX-411 ”,“ Denacol EX-421 ”,“ Denacol EX-512 ”,“ Denacol EX-521 ” , "Denacol EX-611", "Denacol EX-612", "Denacol EX-614", "Denacol EX-614B", "Denacol EX-622", "Denacol EX-810", "Denacol EX-811", "Denacol EX-850", "Denacol EX-850L", "Denacol EX-851", "Denacol EX-821", " Denacol EX-830, "Denacol EX-832", "Denacol EX-841", "Denacol EX-861", "Denacol EX-911", "Denacol EX-941", "Denacol EX-920", "Denacol EX" -931 "(above, manufactured by Nagase ChemteX)," SR-NPG "," SR-16H "," SR-16HL "," SR-TMP "," SR-PG "," SR-TPG "," SR-4PG ”,“ SR-2EG ”,“ SR-8EG ”,“ SR-8EGS ”,“ SR-GLG ”,“ SR-DGE ”,“ SR-DGE ”,“ SR-4GL ”,“ SR- Examples thereof include aliphatic epoxy resins such as "4GLS" and "SR-SEP" (all manufactured by Sakamoto Pharmaceutical Co., Ltd.).

In the coating composition of the present invention, the content of the epoxy resin (C) is 1 to 30% by mass, preferably 5 to 25% by mass, and more preferably 7 to 7 to 30% by mass based on the total resin solid content in the coating composition. 22% by mass is preferable from the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the obtained coating film.

When the polysulfide-modified epoxy resin (C1) is used in the coating composition of the present invention, the content thereof is 1 to 30% by mass, preferably 5 to 25% by mass, based on the total resin solid content in the coating composition. %, More preferably 7 to 22% by mass, is preferable from the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the obtained coating film.

Blocked polyisocyanate compound (D)
In the present invention, known blocked polyisocyanate compounds (D) can be used without limitation.

The blocked polyisocyanate compound (D) is a polyisocyanate compound in which an isocyanate group is blocked by a blocking agent.

A polyisocyanate compound is a compound having at least two isocyanate groups in one molecule. Examples of the polyisocyanate compound include aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic aliphatic polyisocyanates and aromatic polyisocyanates, and derivatives of these polyisocyanates. These can be used alone or in combination of two or more.

Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylenediocyanate, 2,3-butylenediocyanate, and 1,3. -Isocyanates such as butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, diisocyanate dimerate and methyl 2,6-diisocyanatohexanate (common name: lysine diisocyanate), and aliphatic diisocyanates, as well. , 2,6-Diisocyanatohexanoic acid 2-isocyanatoethyl, 1,6-diisocyanato-3-isocyanatomethylhexane, 1,4,8-triisocyanatooctane, 1,6,11-triisocyanatoundecane , 1,8-Diisocyanato-4-isocyanatomethyloctane, 1,3,6-triisocyanatohexane and 2,5,7-trimethyl-1,8-diisocyanato-5-isocyanatomethyloctane. Isocyanate, etc. can be mentioned.

Examples of the alicyclic polyisocyanate include 1,3-cyclopentenediisocyanate, 1,4-cyclohexanediisocyanate, 1,3-cyclohexanediisocyanate, and 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate (common name). : Isophorone diisocyanate), methyl-2,4-cyclohexanediisocyanate, methyl-2,6-cyclohexanediisocyanate, 1,3- or 1,4-bis (isocyanatomethyl) cyclohexane (common name: hydrogenated xylylene diisocyanate) or The mixture, alicyclic diisocyanates such as methylenebis (1,4-cyclohexanediyl) diisocyanate (common name: hydrogenated MDI) and norbornan diisocyanate, and 1,3,5-triisocyanatocyclohexane, 1,3,5- Trimethylisocyanatocyclohexane, 2- (3-isocyanatopropyl) -2,5-di (isocyanatomethyl) -bicyclo (2.2.1) heptane, 2- (3-isocyanatopropyl) -2,6- Di (isocyanatomethyl) -bicyclo (2.2.1) heptane, 3- (3-isocyanatopropyl) -2,5-di (isocyanatomethyl) -bicyclo (2.2.1) heptane, 5- (2-Isocyanatoethyl) -2-isocyanatomethyl-3- (3-isocyanatopropyl) -bicyclo (2.2.1) heptane, 6- (2-isocyanatoethyl) -2-isocyanatomethyl- 3- (3-Isocyanatopropyl) -bicyclo (2.2.1) heptane, 5- (2-isocyanatoethyl) -2-isocyanatomethyl-2- (3-isocyanatopropyl) -bicyclo (2. 2.1) -Alicyclic triisocyanates such as heptane and 6- (2-isocyanatoethyl) -2-isocyanatomethyl-2- (3-isocyanatopropyl) -bicyclo (2.2.1) heptane, And so on.

Examples of the aromatic aliphatic polyisocyanate include methylenebis (1,4-phenylene) diisocyanate (trivial name: MDI), 1,3- or 1,4-xylylene diisocyanate or a mixture thereof, ω, ω'-diisocyanato-. Aromatic aliphatic diisocyanates such as 1,4-diethylbenzene and 1,3- or 1,4-bis (1-isocyanato-1-methylethyl) benzene (trivial name: tetramethylxylylene diisocyanate) or mixtures thereof, and 1,3. , 5-Aromatic aliphatic triisocyanates such as triisocyanatomethylbenzene can be mentioned.

Examples of the aromatic polyisocyanate include m-phenylenedi isocyanate, p-phenylenedi isocyanate, 4,4'-diphenyldiisocyanate, 1,5-naphthalenedi isocyanate, 2,4- or 2,6-tolylene diisocyanate or a mixture thereof. , 4,4'-toluidin diisocyanate and aromatic diisocyanates such as 4,4'-diphenyl ether diisocyanate, triphenylmethane-4,4', 4''-triisocyanate, 1,3,5-triisocyanatobenzene and 2 , 4,6-Triisocyanatotoluene and other aromatic triisocyanates, and 4,4'-diphenylmethane-2,2', 5,5'-tetraisocyanate and other aromatic tetraisocyanates. ..

Examples of the polyisocyanate derivative include dimer, trimmer, biuret, allophanate, uretdione, uretoimine, isocyanurate, oxadiazine trione, and polymethylene polyphenyl polyisocyanate (crude MDI, polypeptide MDI) of the polyisocyanate compound. And crude TDI and the like.

As the polyisocyanate compound, an alicyclic diisocyanate and a derivative of the alicyclic diisocyanate are preferable, and an alicyclic diisocyanate is more preferable, from the viewpoint of chipping resistance, adhesion, and gasoline resistance of the obtained coating film.

The blocked polyisocyanate compound (D) can be obtained, for example, by adding a blocking agent to the isocyanate group of the above polyisocyanate compound. The blocked polyisocyanate compound is stable at room temperature, but when heated to the baking temperature of the coating film (usually about 90 to about 200 ° C.), the blocking agent may dissociate and regenerate free isocyanate groups. It is desirable that it is a thing. Blocking agents that meet these requirements include, for example, phenolic compounds such as phenol, cresol, xylenol, nitrophenol, ethylphenol, hydroxydiphenyl, butylphenol, isopropylphenol, nonylphenol, octylphenol, and methyl hydroxybenzoate; Oximes such as δ-valerolactam, γ-butyrolactam, β-propiolactam; aliphatic alcohols such as methanol, ethanol, propyl alcohol, butyl alcohol, amyl alcohol and lauryl alcohol; ethylene glycol monomethyl ether, ethylene glycol monoethyl Ethers such as ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, and methoxymethanol; benzyl alcohol; glycolic acid; glycolic acid esters such as methyl glycolate, ethyl glycolate, and butyl glycolate. System; Lactic acid ester system such as lactic acid, methyl lactate, ethyl lactate, butyl lactate; Alcohol system such as methylol urea, methylol melamine, diacetone alcohol, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate; formumamide oxime, acetamide oxime, Oxime systems such as acetooxime, methylethylketooxime, diacetylmonooxime, benzophenone oxime, cyclohexaneoxime; dimethyl malonate, diethyl malonate, diisopropyl malate, din-butyl malonate, diethyl methylmalonate, benzylmethyl malonate, malon Malonic acid dialkyl esters such as diphenyl acid, methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate, n-propyl acetoacetate, benzyl acetoacetate, acetylacetate acetate such as phenylacetate, active methylene such as acetylacetone; butyl mercaptan , T-butyl mercaptan, hexyl mercaptan, t-dodecyl mercaptan, 2-mercaptobenzothiazole, thiophenol, methylthiophenol, ethylthiophenol and other mercaptans; Acid amides such as amides and benzamides; succinic acid imides , Imid-based phthalates, imide-based maleates; amine-based such as diphenylamine, phenylnaphthylamine, xylidine, N-phenylxylidine, carbazole, aniline, naphthylamine, butylamine, dibutylamine, butylphenylamine; imidazole, 2-ethyl Imidazoles such as imidazole; Pyrazoles such as 3,5-dimethylpyrazole; Ureas such as urea, thiourea, ethyleneurea, ethylenethiourea, diphenylurea; Carbamate esters such as phenyl N-phenylcarbamate; Ethyleneimine , Imine-based such as propyleneimine; blocking agents such as sodium bisulfate and sulfite-based such as potassium bisulfate. Among these, polyisocyanate blocked with an active methylene-based blocking agent is particularly preferable from the viewpoints of low-temperature curability, chipping resistance of the obtained coating film, adhesiveness, and gasoline property.

In the coating composition of the present invention, the content of the blocked polyisocyanate compound (D) is 1 to 20% by mass, preferably 5 to 15% by mass, based on the total mass of the resin solid content in the coating composition. However, it is suitable from the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the obtained coating film.

Pigment (E)
In the present invention, known pigments (E) can be used without limitation, and for example, coloring pigments, extender pigments, conductive pigments and the like can be used.

Examples of coloring pigments include titanium oxide, carbon black, chrome yellow, ocher, yellow iron oxide, Hansa ello, pigment halo, chrome orange, chrome vermillion, permanent orange, amber, permanent red, brilliant carmine, fast violet, and methyl violet. Examples thereof include rake, ultramarine blue, dark blue, cobalt blue, phthalocyanine blue, pigment green, naphthol green, and aluminum paste, and among these coloring pigments, titanium oxide and carbon black are particularly preferable. These can be used alone or in combination of two or more.

In the coating composition of the present invention, the content of the titanium oxide is 100 to 150% by mass, preferably 110 to 140% by mass, based on the total mass of the resin solid content in the coating composition. It is suitable from the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the film.

Examples of the extender pigment include talc, silica, calcium carbonate, barium sulfate, zinc oxide (zinc oxide) and the like. These can be used alone or in combination of two or more.

The conductive pigment is not particularly limited as long as it can impart conductivity to the formed coating film, and may be in the form of particles, flakes, or fibers (including whiskers). be able to. Specific examples thereof include conductive carbon such as conductive carbon, carbon nanotubes, carbon nanofibers and carbon microcoils; and metal powders such as silver, nickel, copper, graphite and aluminum. In addition, antimony-doped tin oxide, phosphorus-doped tin oxide, tin oxide / antimony-coated acicular titanium oxide, antimony oxide, zinc antimonate, indium tin oxide; on the whisker surface of carbon or graphite. Pigment coated with tin oxide or the like; a flake-shaped mica surface coated with a conductive metal oxide such as tin oxide or antimony-doped tin oxide; a conductive pigment composed of titanium oxide particles containing tin oxide and phosphorus on the surface. And so on. These can be used alone or in combination of two or more. Of these, conductive carbon can be particularly preferably used.

In the coating composition of the present invention, it can be obtained that the content of the conductive carbon is 1 to 10% by mass, preferably 2 to 7% by mass, based on the total mass of the resin solid content in the coating composition. It is suitable from the viewpoint of chipping resistance, adhesion, and gasoline resistance of the coating film.

Other Ingredients The coating composition of the present invention comprises the chlorinated and / or non-chlorinated polyolefin (A), acrylic-modified styrene-based thermoplastic elastomer (B), epoxy resin (C), blocked polyisocyanate compound (D), and the like. And the pigment (E) is an essential component, and a resin component such as a polyester resin, an acrylic resin, a phenol resin and a polycarbonate resin can be contained.

From the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the obtained coating film, the polyester resin is preferably a hydroxyl group-containing polyester resin, and the acrylic resin is preferably a hydroxyl group-containing acrylic resin. Is.

The hydroxyl group-containing polyester resin can be obtained, for example, by subjecting a polybasic acid and a polyhydric alcohol to an esterification reaction with an excess of hydroxyl groups by a method known per se. Polybasic acid is a compound having two or more carboxyl groups in one molecule, for example, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, 1,4-cyclohexanedicarboxylic acid, pyro. Examples thereof include merit acid, itaconic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, dimer acid, hymic acid, succinic acid, het acid, and anhydrides thereof. Polyhydric alcohol is a compound having two or more hydroxyl groups in one molecule, and is, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, butylene glycol, hexanediol, 2-ethyl-2-. Examples thereof include butyl-1,3-propanediol, cyclohexanedimethanol, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol, and sorbitol. The introduction of hydroxyl groups can be carried out, for example, by using a polyhydric alcohol having three or more hydroxyl groups in one molecule in combination. Further, as the polyester resin, a fatty acid-modified polyester resin modified with fatty acids such as soybean oil fatty acid, castor oil fatty acid, and dehydrated castor oil fatty acid can also be used. Further, the polyester resin may be modified with an epoxy compound such as butyl glycidyl ether, alkylphenyl glycidyl ether, neodecanoic acid glycidyl ester, if necessary.

The hydroxyl group-containing polyether resin has a hydroxyl value in the range of 10 to 150 mgKOH / g, particularly in the range of 50 to 85 mgKOH / g, and an acid value of 50 mgKOH / g from the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the obtained coating film. It is appropriate that the amount is g or less, particularly in the range of 1 to 30 mgKOH / g, and the number average molecular weight is in the range of 1,500 to 100,000, particularly 2,000 to 30,000.

When the hydroxyl group-containing polyester resin is used in the coating composition of the present invention, the amount used is 5 to 15% by mass, preferably 7 to 20% by mass, based on the total resin solid content in the coating composition. However, it is suitable from the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the obtained coating film.

The hydroxyl group-containing acrylic resin is usually obtained by using a hydroxyl group-containing polymerizable unsaturated monomer, a (meth) acrylic acid alkyl ester-based monomer, and if necessary, other polymerizable unsaturated monomers, using a known polymerization method, for example, a solution polymerization method or the like. Can be obtained by polymerization.

The hydroxyl group-containing polymerizable unsaturated monomer is a compound having a hydroxyl group and a polymerizable unsaturated group, and is, for example, (meth) such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate. ) A monoesterified product of acrylic acid and a diol having 2 to 10 carbon atoms, and a modified ε-caprolactone of a compound having these hydroxyl groups, a (meth) acryloyl group and a polymerizable unsaturated group can be mentioned.

Examples of the (meth) acrylic acid alkyl ester-based monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and hexyl (meth) acrylate. Examples include monoesters of (meth) acrylic acid and monoalcohol having 1 to 20 carbon atoms, such as -2-ethylhexyl acrylate, lauryl (meth) acrylate, and stearyl (meth) acrylate. can.

The other polymerizable unsaturated monomer is a compound having a polymerizable unsaturated group other than the hydroxyl group-containing polymerizable unsaturated monomer and the (meth) acrylic acid alkyl ester-based monomer, and is, for example, (meth) acrylic acid and maleic acid. Such as carboxyl group-containing polymerizable unsaturated monomer; (meth) glycidyl acrylate and the like epoxy group-containing polymerizable unsaturated monomer; (meth) acrylamide, acrylonitrile, styrene, vinyl acetate, vinyl chloride and the like can be mentioned.

The hydroxyl value-containing acrylic resin has a hydroxyl value of 10 to 100 mgKOH / g, particularly in the range of 50 to 90 mgKOH / g, and an acid value of 0 to 0, from the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the obtained coating film. It is suitable that the weight average molecular weight is in the range of 50 mgKOH / g, particularly 2 to 30 mgKOH / g, and the weight average molecular weight is in the range of 2,000 to 100,000, particularly 3,000 to 50,000.

When the hydroxyl group-containing acrylic resin is used in the coating composition of the present invention, the amount used is 5 to 20% by mass, preferably 7 to 15% by mass, based on the total resin solid content in the coating composition. However, the obtained coating film is suitable from the viewpoint of chipping resistance, adhesiveness, and gasoline resistance of the obtained coating film.

As the phenol resin and the polycarbonate resin, known ones can be used.

The coating composition of the present invention can further contain a curing agent other than the blocked polyisocyanate compound (D), if necessary. Examples of such a curing agent include polyisocyanate compounds and melamine resins.

Examples of the polyisocyanate compound include the polyisocyanate compounds listed in the column of the blocked polyisocyanate compound (D).

As an example of a typical commercially available polyisocyanate compound, "Barnock D-750, -800, DN-950, -970 or 15-455" (manufactured by DIC Co., Ltd., trade name, BURNOCK \ Barnock or Barnock). Is a registered trademark), "Death Module L, N, HL, or N3390" (manufactured by Bayer Actien Gezel Shaft, trade name, Death Module is a registered trademark), "Sumijour N3300, N3390EA" (manufactured by Sumitomo Chemical Co., Ltd., product name) , SUMIDUR \ Sumijuru is a registered trademark) "Takenate D-102, -202, -110 or -123N" (manufactured by Mitsui Kagaku Co., Ltd., trade name, Takenet \ TAKENATE is a registered trademark), "Coronate EH, L, HL or 203 ”(manufactured by Nippon Polyurethane Industry Co., Ltd., trade name, colonate is a registered trademark) or“ Duranate 24A-90CX ”(manufactured by Asahi Kasei Co., Ltd., trade name, DURANATE is a registered trademark), etc. Will be.

As the melamine resin, an alkyl etherified melamine resin etherified with an alkyl group such as methyl, ethyl, n-butyl, isobutyl, hexyl, and 2-ethylhexyl is particularly preferable. These melamine resins may further have a methylol group, an imino group, or the like. The melamine resin usually has a number average molecular weight in the range of 500 to 5,000, particularly preferably 800 to 3,000.

Examples of commercially available melamine resins include butylated melamine resins (Mitsui Toatsu Co., Ltd., Uban 20SE-60, Uban 225, Dainippon Ink Co., Ltd. Super Beccamin G840, Super Beccamin G821, etc.) and methylated melamine resins (such as Dainippon Ink Co., Ltd.). Mitsui Sianamid Co., Ltd. Cymel 303, Sumitomo Chemical Sumimar M-100, Sumimar M-40S, etc.), Methyl etherified melamine resin (Mitsui Sianamid Co., Ltd. Cymel 303, Cymel 325, Cymel 327, Cymel 350, Cymel 370, 3 Nikalac MS17, Nikarak MS15, Symont's Regimin 741, Sumitomo Chemical's Sumimar M55, etc.), methylated, butylated mixed etherified melamine resin (Symel 253, Symel 202, Symel 238, Symel 254 made by Mitsui Sianamid Co., Ltd.) , Cymel 272, Cymel 1130, Sumitomo Chemical's Sumimar M66B, etc.), methylated, isobutylated mixed etherified melamine resin (Mitsui Sianamid Co., Ltd.'s Cymel XV805, Sanwa Chemical's Nicarac MS95, etc.) and other melamine resins can be used. can.

The coating composition of the present invention further contains, if necessary, an organic solvent, a silane coupling agent, a curing catalyst, a thickener, a defoaming agent, a surface conditioner, a coating additive such as a film-forming auxiliary, and the like. can do.

The organic solvent is not particularly limited as long as it can be dissolved or dispersed by mixing the above-mentioned resin components, and is, for example, an aliphatic hydrocarbon solvent, an aromatic hydrocarbon solvent, an alcohol solvent, or an ester solvent. , Solvents such as ketone solvents can be mentioned.

Examples of the silane coupling agent include 2- (3,4 epoxycyclohexyl) ethyltrialkoxysilane, 3-glycidoxypropyltrialkoxysilane, 3-glycidoxypropylmethyldialkoxysilane, and N-2- (amino). Ethyl) -3-aminopropylmethyldialkoxysilane, N-2- (aminoethyl) -3-aminopropyltrialkoxysilane, 3-aminopropyltrialkoxysilane, 3-aminopropylmethyldialkoxysilane, 3-mercaptopropyl Methyldialkoxysilane, 3-mercaptopropyltrialkoxysilane, N-phenyl-3-aminopropyltrialkylsilane, 3-ureidopropyltrialkylsilane, 3-chloropropyltrialkoxysilane, bis (trialkylsilylpropyl) tetrasulfide , 3-Ixylpropyltrialkoxysilane and the like. These can be used alone or in combination of two or more.

Examples of the curing catalyst include quaternary salt catalysts such as tetraethylammonium bromide, tetrabutylammonium bromide, tetraethylammonium chloride, tetrabutylphosphonium bromide, and triphenylbenzylphosphonium chloride; amines such as triethylamine and tributylamine. be able to.

The object to be coated The object to be coated to which the coating composition of the present invention can be applied is not particularly limited, and is, for example, an outer panel of an automobile body such as a passenger car, a truck, a motorcycle, or a bus; an automobile part; a mobile phone. , The outer panel of household electric products such as audio equipment, etc., but metal materials from the viewpoint of taking advantage of the characteristics of the coating composition of the present invention, which has excellent adhesion to both metal materials and plastic materials. And an object to be coated containing a plastic material is preferable.

Examples of the metal material include iron, aluminum, brass, copper, tin, stainless steel, zinc-plated steel, and zinc alloy (for example, Zn-Al, Zn-Ni, Zn-Fe, etc.) plated steel and the like.

The surface of the metal material may be subjected to surface treatment such as phosphate treatment, chromate treatment, composite oxide treatment, etc., and an undercoat coating film with an undercoat paint may be formed on the surface. You may. Examples of the undercoat paint include an electrodeposition paint, and among them, a cationic electrodeposition paint is preferable.

As the plastic material, for example, a polyolefin obtained by (co) polymerizing one or more of olefins having 2 to 10 carbon atoms such as ethylene, propylene, butylene, and hexene is particularly suitable, but other than that. , Polycarbonate, ABS resin, urethane resin, polyamide and the like. Examples of molded products made of these plastic materials include automobile outer panels such as bumpers, spoilers, grills, and fenders; and outer panels of home appliances. Prior to painting the coating composition of the present invention, these plastic molded products can be appropriately subjected to degreasing treatment, washing treatment and the like by a method known per se. Further, the coating composition of the present invention can also be suitably used for molding processing materials such as molding processing films and molding processing sheets containing these plastic materials.

In the coating of the coating composition of the present invention, an air spray, an airless spray, a dip coating, a brush or the like is applied to the object to be coated so that the dry film thickness is usually within the range of 1 to 20 μm, preferably 3 to 15 μm. It is preferable to use it. After coating the composition, the obtained coating film surface can be set at room temperature for about 30 seconds to 60 minutes, if necessary, or at about 60 to about 140 ° C., preferably about 70 to about 120 ° C. It can be cured by heating at a temperature of about 20 to 40 minutes.

In the present invention, the top coat paint can be applied to the coating film surface by the coating composition of the present invention. As the top coat paint, a colored paint or a clear paint may be used independently, or the colored paint may be used as a base coat paint to sequentially paint the base coat paint and the clear paint. The base coat coating film by the above base coat paint may be one layer or two or more layers. When the base coat coating film has two or more layers, the same type of base coat paint may be applied twice or more, or different base coat paints may be applied repeatedly. Further, as a colored base coat coating film layer, for example, a white base paint and an interference pearl color base paint may be sequentially coated on the coating film made of the coating composition of the present invention to form a multi-layer film.

As the coloring paint, those known per se can be used, and usually, an organic solvent and / or water is used as a main solvent, and coloring components such as coloring pigments, bright pigments and dyes, a substrate resin, a cross-linking agent and the like are used. Those containing the resin component of can be used.

Examples of the base resin used in the coloring paint include resins having a reactive functional group such as a hydroxyl group, an epoxy group, a carboxyl group, and a silanol group, such as an acrylic resin, a polyester resin, and an alkyd resin. .. Examples of the cross-linking agent include amino resins such as melamine resins and urea resins having reactive functional groups capable of reacting with the above functional groups, (blocking) polyisocyanates, polyepoxides, polycarboxylic acids and the like.

The colored paint contains paint additives such as extender pigments, curing catalysts, ultraviolet absorbers, coating surface conditioners, rheology control agents, antioxidants, defoamers, waxes, and preservatives, if necessary. be able to.

The colored coating film has a dry film thickness in the range of usually 5 to 50 μm, preferably 5 to 30 μm, and more preferably 10 to 20 μm on the coating film of the uncured or cured coating film composition of the present invention. The resulting coating film surface can be set at room temperature for about 1 to 60 minutes, or preheated at a temperature of about 40 to about 80 ° C. for about 1 to 60 minutes, if necessary. Alternatively, it can be cured by heating at a temperature of about 60 to about 140 ° C., preferably about 80 to about 120 ° C. for about 20 to 40 minutes. In the present invention, it is particularly preferable to perform clear coating without curing the colored base paint after coating.

The clear paint contains, for example, a resin component such as a substrate resin and a cross-linking agent, an organic solvent, water, and the like, and if necessary, an ultraviolet absorber, a light stabilizer, a curing catalyst, a coating surface adjusting agent, and the like. An organic solvent-based or water-based heat-curable paint containing paint additives such as leology control agents, antioxidants, defoamers, and waxes, and the underlying paint can be visually recognized through the formed clear paint. It is possible to use a material having a degree of transparency that can be used.

The substrate resin includes, for example, an acrylic resin, a polyester resin, an alkyd resin, a fluororesin, a urethane resin, and a silicon-containing resin containing at least one reactive functional group such as a hydroxyl group, a carboxyl group, a silanol group, and an epoxy group. Examples thereof include resins such as, and a hydroxyl group-containing acrylic resin is particularly preferable. The cross-linking agent contains a melamine resin, a urea resin, a (block) polyisocyanate compound, an epoxy compound, a carboxyl group-containing compound, an acid anhydride, and an alkoxysilane group having a reactive functional group capable of reacting with these functional groups. Examples thereof include compounds, and polyisocyanate compounds are particularly preferable.

The above-mentioned clear paint is applied on an uncured or cured colored base coating film so that the dry film thickness is usually within the range of 10 to 65 μm, preferably 20 to 60 μm, and the obtained coating film is obtained. If necessary, the surface is set at room temperature for about 1 to 60 minutes, or preheated at a temperature of about 40 to about 80 ° C. for about 1 to 60 minutes, and then about 60 to about 140 ° C., preferably about 70 to about 70 to. This can be done by heating and curing at a temperature of about 120 ° C. for about 20 to 40 minutes.

According to the coating composition of the present invention, it is possible to form a coating film having excellent chipping resistance, adhesiveness, and gasoline resistance with respect to metal materials and plastic materials. The reason why such an excellent coating film can be formed is that the acrylic-modified styrene-based thermoplastic elastomer (B) has a compatibility between a component that contributes to adhesion to a metal material and a component that contributes to adhesion to a plastic material. It is considered that it contributes as an improving component. Further, since the acrylic-modified styrene-based thermoplastic elastomer (B) has rubber elasticity, it is presumed that the obtained coating film has excellent chipping resistance.

Since the coating composition of the present invention has excellent adhesion to metal materials and plastic materials as described above, it is presumed that a coating film having excellent chipping resistance and gasoline resistance can be obtained.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to these examples. In addition, both "part" and "%" are based on the mass standard. The film thickness of the coating film is based on the cured coating film.

Example 1 of Preparation of Paint Composition
Acrylic-modified chlorinated polypropylene (A-1) (toluene solution of acrylic-modified chlorinated polypropylene obtained by grafting methyl methacrylate on maleic acid-modified chlorinated polypropylene having a chlorine content of 17% and a molecular weight of 110,000, an acrylic portion Tg: 75 ° C, acrylic part / polyolefin part ratio: 50/50) 30 parts (solid content), "LGC-010" (trade name, manufactured by Toray Fine Chemical Co., Ltd., acrylic modified SEBS, Tg of acrylic part: 40 ° C. , Acrylic part / SEBS part ratio: 80/20, SEBS part styrene / (ethylene + butylene) weight ratio = 20/80) 50 parts (solid content), "FLEP-50" (trade name, manufactured by Torefine Chemical Co., Ltd.) , Polysulfide modified bisphenol F type epoxy resin, epoxy equivalent: 320, viscosity: 260 Pa · s) 10 parts (solid content), "Duranate MF-K60X" (trade name, manufactured by Asahi Kasei Co., Ltd., active methylene block polyisocyanate compound) 10 parts (Solid content), "Ketchen Black EC300J" (trade name, manufactured by Lion Specialty Chemicals, conductive carbon black pigment) 5 parts (solid content), and "Typure R-902 +" (trade name, manufactured by Chemours). , Titanium oxide) 130 parts (solid content), tetrabutylammonium bromide 0.5 parts mixed in a mixed solvent of xylene / toluene = 1/1, and the viscosity measured using Ford Cup # 4 at 20 ° C. A coating composition (X-1) for 13 seconds was obtained.

Examples 2 to 16 and Comparative Examples 1 to 6
In Example 1, each coating composition (X-2) to (X-22) was obtained in the same manner as in Example 1 except that the compounding composition was as shown in Table 1.

The composition in Table 1 is a solid content display, and each component in Table 1 is as follows.

"NP-3003" trade name, manufactured by Toyobo Co., Ltd., acrylic-modified non-chlorinated polyolefin, Tg of acrylic part: 85 ° C, ratio of acrylic part / polyolefin part: 70/30, solid content 20%,
"Supercron 851L" brand name, manufactured by Nippon Paper Industries, Inc., maleic anhydride-modified chlorinated polypropylene, chlorination rate 19%, solid content 20%,
"Unistor P-902" (trade name, manufactured by Mitsui Chemicals, Inc., hydroxyl group-containing non-chlorinated polyolefin, Mn5000 or higher, hydroxyl value 50 mgKOH / g, solid content 22%,
"KRATON FG1924G" trade name, manufactured by Kraton, acid-modified SEBS, acid value 5 mgCH3ONa / g, styrene / (ethylene + butylene) weight ratio = 13/87,
"Tough Tech M1943" trade name, manufactured by Asahi Kasei Corporation, acid-modified SEBS, acid value 10 mgCH3ONa / g, styrene / (ethylene + butylene) weight ratio = 20/80,
"Tough Tech MP10" trade name, manufactured by Asahi Kasei Corporation, amine-modified SEBS, styrene / (ethylene + butylene) weight ratio = 30/70,
"Tough Tech H1052" brand name, manufactured by Asahi Kasei Corporation, hydrogenated SEBS, styrene / (ethylene + butylene) = 20/80,
"Asaprene T-437" trade name, manufactured by Asahi Kasei Corporation, SBS, styrene / butadiene weight ratio = 30/70,
"Denacol EX-252" brand name, manufactured by Nagase Chemtex, hydrogenated bisphenol A type epoxy resin,
"Baihijour BL5235" trade name, manufactured by Sumika Covestro Urethane, an oxime block polyisocyanate compound.

Preparation of test coating plate Test plate 1
As a plastic material, "TSOP-1 (TC-6)" (trade name, manufactured by Japan Polychem Corporation, 350 mm x 10 mm x 2 mm) was prepared. Then, the surface of the plastic material was wiped with gauze soaked in isopropyl alcohol and degreased.

The coating compositions (X-1) to (X-22) prepared above are spray-coated on the test plate so as to have a dry film thickness of 10 μm, set at room temperature for 3 minutes, and then used as a coloring base paint. "Soflex 420" (trade name, manufactured by Kansai Paint Co., Ltd., solvent-based topcoat base coat paint, silver paint color) was electrostatically coated so as to have a dry film thickness of 15 μm. Next, as a clear paint, "Soflex # 500 Clear" (manufactured by Kansai Paint Co., Ltd., trade name, acrylic urethane-based organic solvent type clear paint) is electrostatically coated so that the dry film thickness is 30 μm, and 5 at room temperature. After leaving it for a minute, it was heated in an oven at 80 ° C. for 30 minutes to obtain a test coating plate on which a multi-layer coating film was formed. Various coating film performance tests described below were performed on the multi-layer coating film.

Test plate 2
As a plastic material, "TSOP-1 (TC-6)" (trade name, manufactured by Japan Polychem Corporation, 350 mm x 10 mm x 2 mm) was prepared. Then, the surface of the plastic material was wiped with gauze soaked in isopropyl alcohol and degreased.

The coating compositions (X-1) to (X-22) prepared above are spray-coated on the test plate so as to have a dry film thickness of 10 μm, set at room temperature for 3 minutes, and then “ZU-10”. (Product name, manufactured by Kansai Paint Co., Ltd., acrylic resin / melamine resin-based organic solvent type intermediate coating paint) was electrostatically coated so as to have a dry film thickness of 15 μm.

After setting at room temperature for 3 minutes, electrostatically apply "Soflex 420" (trade name, manufactured by Kansai Paint Co., Ltd., solvent-based topcoat basecoat paint, silver paint) as a coloring base paint so that the dry film thickness is 15 μm. I painted it.

Next, as a clear paint, "Soflex # 500 Clear" (manufactured by Kansai Paint Co., Ltd., trade name, acrylic urethane-based organic solvent type clear paint) is electrostatically coated so that the dry film thickness is 30 μm, and 5 at room temperature. After leaving it for a minute, it was heated in an oven at 80 ° C. for 30 minutes to obtain a test coating plate on which a multi-layer coating film was formed. Various coating film performance tests described below were performed on the multi-layer coating film.

Test plate 3
As a metal material, a cold-rolled steel sheet (450 mm × 300 mm × 0.8 mm) treated with zinc phosphate was prepared, and a thermosetting epoxy resin-based cationic electrodeposition coating composition (trade name “Electron GT-10”) was prepared thereto. (Kansai Paint Co., Ltd.) was electrodeposited to a thickness of 20 μm and heated at 170 ° C. for 30 minutes to cure.

The coating compositions (X-1) to (X-22) prepared above are spray-coated on the test plate so as to have a dry film thickness of 10 μm, set at room temperature for 3 minutes, and then “ZU-10”. (Product name, manufactured by Kansai Paint Co., Ltd., acrylic resin / melamine resin-based organic solvent type intermediate coating paint) was electrostatically coated so as to have a dry film thickness of 15 μm. Next, "Soflex 420" (trade name, manufactured by Kansai Paint Co., Ltd., solvent-based topcoat base coat paint, silver paint color) was electrostatically coated so as to have a dry film thickness of 15 μm. Next, as a clear paint, "Soflex # 500 Clear" (manufactured by Kansai Paint Co., Ltd., trade name, acrylic urethane-based organic solvent type clear paint) is electrostatically coated so that the dry film thickness is 30 μm, and 5 at room temperature. After leaving it for a minute, it was heated in an oven at 80 ° C. for 30 minutes to obtain a test coating plate on which a multi-layer coating film was formed. Various coating film performance tests described below were performed on the multi-layer coating film.

Coating performance test Chipping resistance: A test coating plate is installed on the sample holding table of a stepping stone tester (trade name "QGR Granite Meter" (manufactured by Q Panel)), and from the test plate at -20 ° C. 100 g of granite crushed stone having a particle size of No. 6 was collided with a test plate at an angle of 90 degrees with compressed air of 480 to 520 kPa from a distance of 30 cm. Then, the obtained test plate was washed with water, dried, and applied to the coated surface. A cloth adhesive tape (manufactured by Nichiban Co., Ltd.) was attached. Then, the tape was peeled off and evaluated based on the area where the electrodeposited surface and the base member were exposed (abbreviated as peeled area).
A: The ratio of the peeling area to the test coating area is less than 3% B: The ratio of the peeling area to the test coating area is less than 3 to 6% C: The ratio of the peeling area to the test coating area is less than 6 to 10% D: The test coating plate The ratio of the peeled area to the area is 10% or more.

Water resistance: Immerse the test coating plate in warm water at 40 ° C for 240 hours, pull it up, dry it at 20 ° C for 12 hours, and then cut the multi-layer coating film of the test coating plate in a grid pattern with a cutter so that it reaches the substrate. Make 100 2mm x 2mm goban eyes. Subsequently, an adhesive cellophane tape was attached to the surface thereof, and the residual state of the Goban-mesh coating film after the tape was rapidly peeled off at 20 ° C. was examined, and the water resistance was evaluated according to the following criteria.
A: 100 Goban-grained coating films remain and no small edge of the coating film is generated at the edge of the notch of the cutter. B: 100 Goban-grained coating films remain but the coating film is small at the edge of the notch of the cutter. The number of remaining C: Goban-grained coating films with borders is 99 to 90.
D: The number of remaining Goban-grain coating films is 89 or less.

Moisture resistance: The test coating plate is allowed to stand in a constant temperature room at room temperature of 50 ° C. and relative humidity of 95% for 240 hours, and then allowed to stand at 20 ° C. for 12 hours, so that the multi-layer coating film of the test coating plate reaches the substrate. Cut in a grid pattern with a cutter to make 100 Goban eyes with a size of 2 mm x 2 mm. Subsequently, an adhesive cellophane tape was attached to the surface thereof, and the residual state of the Goban-mesh coating film after the tape was rapidly peeled off at 20 ° C. was examined, and the moisture adhesion resistance was evaluated according to the following criteria.
A: 100 Goban-grained coating films remain and no small edge of the coating film is generated at the edge of the notch of the cutter. B: 100 Goban-grained coating films remain but the coating film is small at the edge of the notch of the cutter. The number of remaining C: Goban-grained coating films with borders is 99 to 90.
D: The number of remaining Goban-grain coating films is 89 or less.

Gasoline resistance: The appearance of the coating film after immersing the test plate in Nisseki silver gasoline at 20 ° C. for 1 hour was evaluated according to the following criteria.
A: No abnormality at all,
B: Blisters or peeling with a diameter of less than 1 mm have occurred.
C: Blisters or peeling with a diameter of 1 mm or more and less than 2 mm D: Blisters or peeling with a diameter of 2 mm or more have occurred.

Paint stability: The paint composition prepared above was placed in a 100 mL glass container and stored in a closed container at 35 ° C. for 35 days. The subsequent condition was judged according to the following criteria.
A: Good without change from before storage B: Slight layer separation is observed, but returns to the original state with stirring C: Complete layer separation is observed, but returns to the original state with stirring.
D: Complete layer separation is observed and cannot be used as a paint.

Claims (4)

The object to be coated contains chlorinated and / or non-chlorinated polyolefin (A), acrylic-modified styrene-based thermoplastic elastomer (B), epoxy resin (C), blocked polyisocyanate compound (D), and pigment (E). A coating method comprising painting a coating composition , applying a base coat paint on the uncured surface, and then applying a clear coat paint on the uncured surface and curing . The acrylic-modified styrene-based thermoplastic elastomer (B) includes an acrylic portion and a styrene-based thermoplastic elastomer portion.
The glass transition temperature of the acrylic portion of the acrylic-modified styrene-based thermoplastic elastomer (B) is 20 to 100 ° C., and the solid content mass ratio between the acrylic portion and the styrene-based thermoplastic elastomer portion is 1: 9 to 9. The coating method according to claim 1, wherein the ratio is 1. The coating method according to claim 1 or 2, wherein the epoxy resin (C) is a polysulfide-modified epoxy resin (C1). The coating method according to any one of claims 1 to 3, wherein the blocked polyisocyanate compound (D) is an active methylene-based blocked polyisocyanate compound.