JP2019167390A - Coating composition - Google Patents

Abstract

To provide a coating composition that can form a coating film having excellent chipping resistance, adhesion and gasoline resistance to both of metal material and plastic material.SOLUTION: A coating composition contains chlorinated and/or non-chlorinated polyolefin (A), acryl-modified styrenic thermoplastic elastomer (B), epoxy resin (C), block polyisocyanate compound (D), and pigment (E).SELECTED DRAWING: None

Description

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

  In general, an automobile body has a metal material forming a body and a plastic material forming a bumper or the like. Since the polarities of metal materials and plastic materials are completely different, paints for metal materials are difficult to 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 coated with the same undercoat, cost reduction can be expected in the production of an automobile body.

  As a technique for improving adhesion to a metal material and a plastic material, for example, Patent Document 1 discloses (A) a styrene / isoprene block copolymer or a hydrogenated product thereof, a monoolefin dicarboxylic acid and an anhydride thereof, and a monovalent compound. A modified copolymer obtained by graft copolymerization so as to contain 0.05 to 20% by weight of at least one modified monomer selected from monoalkyl esters of olefin dicarboxylic acid, (B) a polyester resin, and (C) A primer composition containing an organic solvent is disclosed.

  However, the primer composition disclosed in Patent Document 1 is about gasoline resistance and resistance to chipping phenomenon in which a coating film peels off when a pebbles collides with a painted surface of an automobile body outer plate, that is, chipping resistance. It was not considered.

  Patent Document 2 discloses that a styrene / isoprene block copolymer or a hydrogenated product thereof, at least one modified monomer selected from a monoolefin dicarboxylic acid and its anhydride, and a monoalkyl ester of a monoolefin dicarboxylic acid. It contains a modified graft copolymer (A) obtained by adding a monoepoxy compound (b) to a graft copolymer (a) obtained by graft copolymerization, and an organic solvent (B) as main components. A coating composition is disclosed.

  However, the coating composition disclosed in Patent Document 2 has not been considered for gasoline resistance.

JP-A-6-57202 JP-A-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, adhesion, and gasoline resistance to metal materials and plastic materials. For the purpose.

  As a result of intensive studies to achieve the above object, the present inventors have made chlorinated and / or non-chlorinated polyolefin (A), acrylic-modified styrenic thermoplastic elastomer (B), epoxy resin (C), By using the coating composition containing the block polyisocyanate compound (D) and the pigment (E), it has been found that the above problems can be solved, 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 styrenic thermoplastic elastomer (B), an epoxy resin (C), a block polyisocyanate compound (D), and a pigment (E).
Item 2.
The acrylic-modified styrenic thermoplastic elastomer (B) includes an acrylic part and a styrenic thermoplastic elastomer part,
The glass part transition temperature of the acrylic part of the acrylic modified styrenic thermoplastic elastomer (B) is 20 to 100 ° C., and the solid content mass ratio of the acrylic part and the styrenic thermoplastic elastomer part is 5: 5-9. Item 1. The coating composition according to Item 1, wherein
Item 3.
Item 3. The coating composition according to Item 1 or 2, wherein the epoxy resin (C) is a polysulfide-modified epoxy resin (C1).
Item 4.
Item 4. The coating composition according to any one of Items 1 to 3, wherein the block polyisocyanate compound (D) is an active methylene-based block polyisocyanate compound.
Item 5.
Item 5. A coating method comprising applying a coating composition according to any one of Items 1 to 4 to an object to be coated, and then applying a top coating to the coated surface.
Item 6.
The coating composition according to any one of Items 1 to 4 is applied to an object to be coated, a base coat paint is applied to the uncured coating surface, and a clear coat paint is applied to the uncured coating surface. A method of painting, including painting and curing.

  According to the coating composition of the present invention, a coating film having excellent chipping resistance, adhesion, and gasoline resistance can be formed on metal materials and plastic materials without using a dedicated 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 styrenic thermoplastic elastomer (B), an epoxy resin (C), a block polyisocyanate compound (D), and a pigment (E ).

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). These can be used alone or in combination of two or more.

  The chlorinated polyolefin resin (A1) is a chlorinated product of polyolefin, and the polyolefin used as the substrate is, for example, a radical homopolymer of at least one olefin selected from ethylene, propylene, butene, methylbutene, isoprene and the like. Alternatively, a copolymer and a radical copolymer of the olefin with vinyl acetate, butadiene, or the like can be given. The chlorinated polyolefin can generally have a weight average molecular weight in the range of about 30,000 to 200,000, especially 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. If the chlorine content is within this range, the solubility in the solvent does not decrease, so 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 such as maleic acid, fumaric acid, itaconic acid, (meth) acrylic acid (preferably unsaturated mono- or di-carboxylic acid) or anhydrous anhydrides of these unsaturated carboxylic acids. Those obtained by graft polymerization according to a method known per se can be used, and those modified with maleic anhydride are preferred.

  In the coating composition of the present invention, when the chlorinated polyolefin (A1) is used, its content 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, the content is 12 to 25% by mass from the viewpoints of chipping resistance, adhesion, and gasoline resistance of the obtained coating film.

  Examples of the non-chlorinated polyolefin resin (A2) include 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 ( Polyolefins obtained by co) polymerization, and the polyolefins with unsaturated carboxylic acids (preferably unsaturated mono- or di-carboxylic acids) such as maleic acid, fumaric acid, itaconic acid, (meth) acrylic acid, or the like Those obtained by graft polymerization using an unsaturated carboxylic acid anhydride according to a method known per se can be used, and those modified with maleic anhydride are particularly preferred. 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.

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

  The acrylic-modified chlorinated polyolefin (A3) is obtained by modifying a chlorinated polyolefin with an acrylic resin, and includes an acrylic portion and a chlorinated polyolefin portion.

  As a method for obtaining the acrylic-modified chlorinated polyolefin (A3), for example, an α, β-unsaturated carboxylic acid and / or an acid anhydride thereof is graft copolymerized with the polyolefin to obtain an acid-modified polyolefin (a1). The acid-modified polyolefin (a1) is chlorinated to give an acid-modified chlorinated polyolefin (a2), and then in the presence of a polymerization initiator, a polymerizable unsaturated monomer containing a hydroxyl group-containing (meth) acrylic acid ester is graft-polymerized. A method of performing acrylic modification, esterifying by reacting the acid-modified chlorinated polyolefin (a2) with a hydroxyl group-containing (meth) acrylic ester to introduce double bonds into the acid-modified chlorinated polyolefin (a2). After obtaining a bond-introduced chlorinated polyolefin, a grafted unsaturated monomer is grafted onto the double-bond-introduced chlorinated polyolefin. There are methods such as polymerization and acrylic modification.

  In the present specification, “(meth) acrylate” means acrylate or methacrylate, and “(meth) acrylic acid” means acrylic acid or methacrylic acid.

  Examples of the polyolefin include (co) polymerizing 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. Examples of the resin to be obtained include.

  Examples of the α, β-unsaturated carboxylic acid and / or acid anhydride thereof include unsaturated carboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, and (meth) acrylic acid, or unsaturated carboxylic acids thereof. The anhydrides of these are mentioned, and maleic acid and maleic anhydride are particularly preferred. 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, polypropylene glycol (meth) acrylate and the like. (Meth) acrylic acid ester having one hydroxyl group is mentioned, and 2-hydroxyethyl (meth) acrylate is 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 acid such as (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate; (meth) acrylic acid, glycidyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth ) Acrylic monomers such as acrylamide and (meth) acrylonitrile; and styrene and the like. Among them, butyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate Door is preferable. These can be used alone or in combination of two or more.

  The graft copolymerization and esterification reaction can be performed by a method known per se.

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

  In the present invention, the acrylic-modified chlorinated polyolefin (A3) has a glass transition temperature of 20 to 100 ° C., preferably 25 to 90, from the viewpoint of chipping resistance, adhesion, and gasoline resistance of the resulting coating film. ° C, more preferably 30 to 85 ° C, and the mass ratio of the solid content of the acrylic part to the chlorinated polyolefin part 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, adhesion, and gasoline resistance of the resulting 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 are the mass fractions of the respective monomers, and T1, T2... Tn are the glass transition temperatures Tg (K) of the homopolymers of the respective monomers.
The glass transition temperature of the homopolymer of each monomer is described in POLYMERHANDBOOKFourth Edition, J. MoI. Brandrup, E .; h. Immergut, E .; A. The glass transition temperature of a monomer not described in this document, which is a value according to Grulk ed. (1999), was synthesized such that the monomer homopolymer had a weight average molecular weight of about 50,000, and its glass transition. The value when the temperature is measured by differential scanning thermal analysis is used.

  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 based on the total resin solid content in the coating composition. Is preferably from 12 to 25% by mass from the viewpoint of chipping resistance, adhesion and gasoline resistance of the resulting coating film.

  The acrylic-modified non-chlorinated polyolefin (A4) is obtained by modifying a non-chlorinated polyolefin with an acrylic resin, and includes an acrylic portion and a non-chlorinated polyolefin portion.

  As a method for obtaining the acrylic-modified non-chlorinated polyolefin (A4), for example, after α-, β-unsaturated carboxylic acid and / or acid anhydride thereof is graft-copolymerized to polyolefin, acid-modified polyolefin (a1) is obtained. 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 perform acrylic modification, or a hydroxyl group-containing (meth) acrylic acid to the acid-modified polyolefin (a1). After esterification and esterification, a double bond is introduced into the acid-modified polyolefin (a1) to obtain a double bond-introduced polyolefin. Then, a polymerizable unsaturated monomer is graft-copolymerized on 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 mentioned in the item of the acrylic-modified chlorinated polyolefin (A3) can be used.

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

  In the present invention, the acrylic-modified unmodified polyolefin (A4) has a glass transition temperature of 20 to 100 ° C., preferably 25 to 25 ° C., from the viewpoint of chipping resistance, adhesion, and gasoline resistance of the resulting coating film. 90 ° C., more preferably 30 to 85 ° C., and the solid content mass ratio of the acrylic part to the non-chlorinated polyolefin part 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, adhesion, and gasoline resistance of the resulting coating film.

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

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

As a method for obtaining the acrylic-modified styrenic thermoplastic elastomer (B), for example,
[I] A method of acrylic modification by a hydrogen abstraction reaction from a styrene-based thermoplastic elastomer (b1);
[II] Styrenic thermoplastic elastomer (b3) having an acid group is obtained by graft copolymerization of α, β-unsaturated carboxylic acid and / or acid anhydride (b2) with styrene thermoplastic elastomer (b1). And then acrylic-modifying by graft copolymerizing a polymerizable unsaturated monomer in the presence of a polymerization initiator;
[III] A hydroxyl group-containing (meth) acrylic ester is reacted with the styrenic thermoplastic elastomer (b3) having an acid group for esterification to introduce a double bond into the styrene thermoplastic elastomer (b3) having an acid group. A double bond-introduced styrene-based thermoplastic elastomer (b4), and then graft-copolymerizing a polymerizable unsaturated monomer on the double-bond-introduced styrene-based thermoplastic elastomer (b4) for acrylic modification;
Etc.

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

  Examples of the styrenic thermoplastic elastomer (b1) include blocks and random copolymers of styrene and olefins and / or conjugated dienes: for example, styrene-olefins and / or conjugated diene block copolymers (styrene-olefins and / or conjugated dienes). Diblock copolymers, triblock copolymers, etc .; styrene-olefin and / or conjugated diene-styrene triblock copolymers, tetrablock copolymers, etc.), styrene-conjugated diene random copolymers, and these And hydrogenated products of these, as well as mixtures of two or more of these.

  Examples of the olefin constituting the copolymer include those having 2 to 12 or more carbon atoms, such as ethylene, propylene, 1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, and 3-methyl. As a conjugated diene, a C4-C20 α-olefin such as -1-pentene, 1-heptene, 1-hexene, 1-octene, 1-decene, 1-dodecene, etc. C4 to C20, such as butadiene, isoprene, and combinations 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 and random copolymers of styrene and olefins such as propylene-styrene block copolymer (SEEPS); styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene-styrene block copolymer (SBS), Blocks and random copolymers of styrene and conjugated dienes, such as random copolymers of styrene-butadiene; and hydrogenated products of these copolymers (eg hydrogenated SEBS, hydrogenated SBS, hydrogenated SIS); and these A mixture of two or more of That. The styrenic 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 resulting coating film. (SEBS), particularly hydrogenated SEBS is preferred.

  The method for preparing the hydrogenated product of the styrenic 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 hydrogenation catalyst. The method etc. are mentioned.

  As the styrene-based thermoplastic elastomer (b1), those having a styrene content of 10 to 50% by mass, particularly 15 to 45% by mass based on the mass of the copolymer are preferred.

  Further, the weight average molecular weight [polystyrene equivalent 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, especially 10 1,000 to 200,000 are preferred.

  The α, β-unsaturated carboxylic acid or anhydride (b2) is usually added to the styrenic thermoplastic elastomer (b1) by graft polymerization. Examples of the α, β-unsaturated carboxylic acid compounds include (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, citraconic acid and acid anhydrides thereof, α, β-unsaturated. And alkyl esterified products of saturated carboxylic acids. Specific examples of alkyl esterified products of α, β-unsaturated carboxylic acids 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 and the like. 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, as the α, β-unsaturated carboxylic acid or anhydride (b2), maleic acid, anhydride, and gasoline resistance are obtained from the viewpoint of chipping resistance, adhesion, and gasoline resistance. Maleic acid, itaconic acid and itaconic anhydride are preferred.

  The amount of the α, β-unsaturated carboxylic acid or 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 styrenic thermoplastic elastomer (b1). % Is preferred.

The styrenic 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 resulting coating film. ₃ ONa / g, more preferably 5-15 mg CH3ONa / 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 resulting coating film. It 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 resulting coating film. / 50, preferably 7/93 to 45/55, more preferably 10/90 to 40/60.

  As the hydroxyl group-containing (meth) acrylic acid ester and polymerizable unsaturated monomer to be reacted with the styrene-based thermoplastic elastomer (b3) having an acid group, those mentioned 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 styrenic 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 from the viewpoint of chipping resistance, adhesion and gasoline resistance of the resulting coating film.

  In the coating composition of the present invention, a styrenic thermoplastic elastomer other than the acrylic-modified styrenic thermoplastic elastomer (B) can be used in combination as required. Examples of such a styrene-based thermoplastic elastomer include the styrene-based thermoplastic elastomer (b3) having the acid group.

  As a commercial item of the styrene-type thermoplastic elastomer (b3) which has an acid group, for example, trade names “Tuff Tech M1943”, “Tuff Tech M1913”, “Tuff Tech M1911” manufactured by Asahi Kasei Co., Ltd., trade names manufactured by Kraton Polymer Japan Co., Ltd. “KRATON FG1901G”, “KRATON FG1924G” and the like. 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 using the styrenic thermoplastic elastomer (b3) having an acid group is 15 to 60 on the basis of the total resin solid content in the coating composition. The mass%, preferably 20 to 55 mass%, more preferably 25 to 50 mass% is suitable from the viewpoint of chipping resistance, adhesion and gasoline resistance of the resulting coating film.

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

  Examples of the epoxy resin include bisphenol A type epoxy resin; bisphenol F type epoxy resin; novolac type epoxy resin; hydrogenated bisphenol A type epoxy resin; ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, 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 Aliphatic types such as polyglycidyl ether and polyglycerin polyglycidyl ether Epoxy resins; biphenyl type epoxy resin; dicyclopentadiene type epoxy resin; polysulfide-modified epoxy resin (C1); and the like. These can be used alone or in combination of two or more.

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

  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, adhesion, and gasoline resistance of the coating film to be formed. Is preferred. Moreover, it is preferable that this epoxy resin has a hydroxyl group from a viewpoint of the chipping resistance of the coating film formed, adhesiveness, and gasoline resistance.

  In particular, it is preferable to use the polysulfide-modified epoxy resin (C1) from the viewpoints of chipping resistance, adhesion, 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 (—R—S—S—) in the molecular main chain.

  Examples of the organic group containing a bisphenol skeleton include a bisphenol A type epoxy resin, a bisphenol AD type epoxy resin, a halogenated bisphenol A type epoxy resin, a bisphenol F type epoxy resin, and a halogenated bisphenol F type epoxy resin. . Among these, bisphenol F type epoxy resin is preferred from the viewpoint of gasoline resistance and adhesion of the coating film obtained.

  The polysulfide-modified epoxy resin (C1) has a number average molecular weight of 110 to 4,500, preferably 900 to 3,500, and 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 to be in the range of 150 to 350 g / equivalent.

  As the polysulfide-modified epoxy resin (C1), those having a viscosity at 25 ° C. of 3000 poises or less, preferably 100 to 300 poises are preferable from the viewpoint of easy handling.

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

  Examples of commercially available epoxy resins other than the polysulfide-modified epoxy resin (C1) include, for example, “jER828,” “jER828,” “jER828EL,” “jER828XA,” “jER834” (above, manufactured by Japan Epoxy Resin Co., Ltd.), “ “EPICLON 840”, “EPICLON 840-S”, “EPICLON 850”, “EPICLON 850-S”, “EPICLON 850-CRP”, “EPICLON 850-LC” (manufactured by DIC), “Epototo YD-127”, “Epototo YD-128” ”(Above, manufactured by Toto Kasei Co., Ltd.),“ Lika Resin BPO-20E ”,“ Lika Resin BEO-60E ”(above, Shin Nippon Rika Co., Ltd.), etc .;“ jER806 ”,“ jER807 ”(above, Japan Bisphenol F type epoxy resin such as “EPICLON 830”, “EPICLON 830-S”, “EPICLON 835” (manufactured by DIC), “Epototo YDF-170” (manufactured by Tohto Kasei Co., Ltd.); Novolak type epoxy resin such as “Japan Epoxy Resin Co., Ltd.”; “jERYX8000”, “jERYX8034” (manufactured by Japan Epoxy Resin Co., Ltd.), “Epototo ST-3000” (manufactured by Tohto Kasei Co., Ltd.), “Rikaresin HBE-100” ( Hydrogenated bisphenol A type epoxy resins such as “Denacol EX-252” (manufactured by Nagase ChemteX), “SR-HBA” (manufactured by Sakamoto Pharmaceutical Co., Ltd.); YED216M ”,“ YED216D ”(above, Japan “Xepotine YH-300”, “Epototo YH-301”, “Epototo YH-315”, “Epototo YH-324”, “Epototo YH-325” (above, manufactured by Toto Kasei), “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 "(manufactured by Nagase ChemteX Corporation)," 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-4GLS", "SR-SEP" (or, BanHajime Yakuhin Kogyo Co., Ltd.) aliphatic epoxy resins such as, and the like.

  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, more preferably 7 to 7% by mass based on the total resin solid content in the coating composition. It is suitable that it is 22 mass% from the point of the chipping resistance of the coating film obtained, adhesiveness, and gasoline resistance.

  In the coating composition of the present invention, when the polysulfide-modified epoxy resin (C1) is used, 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, from the viewpoint of chipping resistance, adhesion and gasoline resistance of the resulting coating film.

Block polyisocyanate compound (D)
In the present invention, any known block polyisocyanate compound (D) can be used without limitation.

  The blocked polyisocyanate compound (D) is a polyisocyanate compound in which isocyanate groups are blocked with a blocking agent.

  The polyisocyanate compound is a compound having at least two isocyanate groups in one molecule. Examples of the polyisocyanate compound include aliphatic polyisocyanates, alicyclic polyisocyanates, araliphatic 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-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3. -Aliphatic diisocyanates such as butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, dimer acid diisocyanate and methyl 2,6-diisocyanatohexanoate (common name: lysine diisocyanate), and 2,6-diisocyanatohexanoic acid 2-isocyanatoethyl, 1,6-diisocyanato-3-isocyanatomethylhexane, 1,4,8-triisocyanatoocta 1,6,11-triisocyanatoundecane, 1,8-diisocyanato-4-isocyanatomethyloctane, 1,3,6-triisocyanatohexane and 2,5,7-trimethyl-1,8-diisocyanato- And aliphatic triisocyanates such as 5-isocyanatomethyloctane.

  Examples of the alicyclic polyisocyanate include 1,3-cyclopentene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (common name) : Isophorone diisocyanate), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,3- or 1,4-bis (isocyanatomethyl) cyclohexane (common name: hydrogenated xylylene diisocyanate) or Mixtures thereof, alicyclic diisocyanates such as methylene bis (1,4-cyclohexanediyl) diisocyanate (common name: hydrogenated MDI) and norbornane diisocyanate, and 1,3,5-tri Socyanatocyclohexane, 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-isocyanate) Natoethyl) -2-isocyanatomethyl-3- (3-isocyanatopropyl) -bicyclo (2.2.1) heptane, 5- (2-isocyanatoethyl) -2-isocyanate Tomethyl-2- (3-isocyanatopropyl) -bicyclo (2.2.1) -heptane and 6- (2-isocyanatoethyl) -2-isocyanatomethyl-2- (3-isocyanatopropyl) -bicyclo (2.2.1) Alicyclic triisocyanates such as heptane, and the like.

  Examples of the araliphatic polyisocyanate include methylene bis (1,4-phenylene) diisocyanate (common 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 (common name: tetramethylxylylene diisocyanate) or mixtures thereof and 1,3 , 5-triisocyanatomethylbenzene and other araliphatic triisocyanates.

  Examples of the aromatic polyisocyanate include m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 2,4- or 2,6-tolylene diisocyanate, or a mixture thereof. Aromatic diisocyanates such as 4,4′-toluidine diisocyanate and 4,4′-diphenyl ether diisocyanate, triphenylmethane-4,4 ′, 4 ″ -triisocyanate, 1,3,5-triisocyanatobenzene and 2 Aromatic triisocyanates such as 4,4,6-triisocyanatotoluene, aromatic tetraisocyanates such as 4,4′-diphenylmethane-2,2 ′, 5,5′-tetraisocyanate, and the like. .

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

  The polyisocyanate compound is preferably an alicyclic diisocyanate or a derivative of the alicyclic diisocyanate, and more preferably an alicyclic diisocyanate from the viewpoint of chipping resistance, adhesion, and gasoline resistance of the resulting coating film.

  The block polyisocyanate compound (D) can be obtained, for example, by adding a blocking agent to the isocyanate group of the polyisocyanate compound. The block polyisocyanate compound is stable at ordinary temperature, but when heated to the baking temperature of the coating film (usually about 90 to about 200 ° C.), the blocking agent can be dissociated to regenerate free isocyanate groups. It is desirable to be a thing. Examples of the blocking agent satisfying such requirements include phenols such as phenol, cresol, xylenol, nitrophenol, ethylphenol, hydroxydiphenyl, butylphenol, isopropylphenol, nonylphenol, octylphenol, and methyl hydroxybenzoate; ε-caprolactam, Lactams such as δ-valerolactam, γ-butyrolactam, β-propiolactam; aliphatic alcohols such as methanol, ethanol, propyl alcohol, butyl alcohol, amyl alcohol, lauryl alcohol; ethylene glycol monomethyl ether, ethylene glycol monoethyl Ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol Ethers such as ethyl ether, propylene glycol monomethyl ether and methoxymethanol; benzyl alcohol; glycolic acid; glycolic acid esters such as methyl glycolate, ethyl glycolate and butyl glycolate; lactic acid, methyl lactate, ethyl lactate and butyl lactate Lactic acid ester system: methylol urea, methylol melamine, diacetone alcohol, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and other alcohol systems; formamide oxime, acetamide oxime, acetoxime, methyl ethyl ketoxime, diacetyl monooxime, benzophenone oxime, Oximes such as cyclohexane oxime; dimethyl malonate, diethyl malonate, diisopropyl malonate, dimalonate Malonic acid dialkyl esters such as n-butyl, diethyl methylmalonate, benzylmethyl malonate, diphenyl malonate, methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate, n-propyl acetoacetate, benzyl acetoacetate, phenyl acetoacetate, etc. Active methylenes such as acetoacetate, acetylacetone, etc .; mercaptans such as butyl mercaptan, t-butyl mercaptan, hexyl mercaptan, t-dodecyl mercaptan, 2-mercaptobenzothiazole, thiophenol, methylthiophenol, ethylthiophenol; acetanilide , Acetanisids, acetolides, acrylamides, methacrylamides, acetic acid amides, stearic acid amides, benzamides and other acid amides; succinimides, Imide systems such as taric acid imide and maleic acid imide; amine systems such as diphenylamine, phenylnaphthylamine, xylidine, N-phenylxylidine, carbazole, aniline, naphthylamine, butylamine, dibutylamine, butylphenylamine; imidazole, 2-ethylimidazole Imidazoles such as; pyrazoles such as 3,5-dimethylpyrazole; ureas such as urea, thiourea, ethyleneurea, ethylenethiourea, diphenylurea; carbamate esters such as phenyl N-phenylcarbamate; ethyleneimine, Examples thereof include blocking agents such as imines such as propylene imine; sulfites such as sodium bisulfite and potassium bisulfite. Of these, polyisocyanates blocked with an active methylene-based blocking agent are particularly preferred from the viewpoints of low-temperature curability, chipping resistance of the resulting coating film, adhesion, and gasoline properties.

  In the coating composition of the present invention, the content of the block polyisocyanate compound (D) is 1 to 20% by mass, preferably 5 to 15% by mass, based on the total resin solid content in the coating composition. Is preferable from the viewpoint of chipping resistance, adhesion, and gasoline resistance of the resulting coating film.

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

  Examples of color pigments include titanium oxide, carbon black, chrome lead, ocher, yellow iron oxide, Hansa Yellow, pigment yellow, chrome orange, chrome vermillion, permanent orange, amber, permanent red, brilliant carmine, fast violet, and methyl violet. Examples include lake, ultramarine blue, bitumen, cobalt blue, phthalocyanine blue, pigment green, naphthol green, and aluminum paste. Among these colored 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 resin solid mass in the coating composition. It is suitable from the viewpoint of chipping resistance, adhesion and gasoline resistance of the film.

  Examples of extender pigments include talc, silica, calcium carbonate, barium sulfate, and zinc white (zinc oxide). 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 coating film to be formed, and any pigment, flake, or fiber (including whisker) shape can be used. be able to. Specifically, for example, conductive carbon such as conductive carbon, carbon nanotube, carbon nanofiber, and carbon microcoil; metal powder such as silver, nickel, copper, graphite, and aluminum can be used. In addition, tin oxide doped with antimony, tin oxide doped with phosphorus, acicular titanium oxide coated with tin oxide / antimony, antimony oxide, zinc antimonate, indium tin oxide; on the whisker surface of carbon or graphite A pigment coated with tin oxide or the like; a pigment coated with a conductive metal oxide such as tin oxide or antimony-doped tin oxide on a flaky mica surface; a conductive pigment comprising titanium oxide particles containing tin oxide and phosphorus on the surface; Etc. 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, the content of the conductive carbon is 1 to 10% by mass, preferably 2 to 7% by mass, based on the total resin solid mass in the coating composition. It is preferable from the viewpoint of chipping resistance, adhesion, and gasoline resistance of the coating film.

Other components The coating composition of the present invention comprises the chlorinated and / or non-chlorinated polyolefin (A), the acrylic-modified styrenic thermoplastic elastomer (B), the epoxy resin (C), the block polyisocyanate compound (D), And pigment (E) as essential components, and can contain resin components such as polyester resin, acrylic resin, phenol resin and polycarbonate resin.

  From the viewpoint of chipping resistance, adhesion, and gasoline resistance of the resulting 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. It 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. A 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 include merit acid, itaconic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, dimer acid, hymic acid, succinic acid, het acid, and anhydrides thereof. The polyhydric alcohol is a compound having two or more hydroxyl groups in one molecule, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, butylene glycol, hexanediol, 2-ethyl-2- Examples include butyl-1,3-propanediol, cyclohexanedimethanol, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitol and the like. Introduction of a hydroxyl group can be performed by using, for example, a polyhydric alcohol having 3 or more hydroxyl groups in one molecule. Further, as the polyester resin, a fatty acid-modified polyester resin modified with a fatty acid such as soybean oil fatty acid, castor oil fatty acid, dehydrated castor oil fatty acid or the like can also be used. Moreover, the polyester resin may be modified with an epoxy compound such as butyl glycidyl ether, alkylphenyl glycidyl ether, or neodecanoic acid glycidyl ester, if necessary.

  The hydroxyl group-containing polyether resin has a hydroxyl value of 10 to 150 mgKOH / g, particularly 50 to 85 mgKOH / g, and an acid value of 50 mgKOH / g from the viewpoint of chipping resistance, adhesion and gasoline resistance of the resulting coating film. It is suitable that it is not more than g, particularly in the range of 1 to 30 mg KOH / g, and the number average molecular weight is in the range of 1,500 to 100,000, particularly 2,000 to 30,000.

  In the coating composition of the present invention, when the hydroxyl group-containing polyester resin is used, the amount used thereof is 5 to 15% by mass, preferably 7 to 20% by mass, based on the total resin solid content in the coating composition. Is preferable from the viewpoint of chipping resistance, adhesion, and gasoline resistance of the resulting coating film.

  A hydroxyl group-containing acrylic resin is usually a hydroxyl group-containing polymerizable unsaturated monomer, a (meth) acrylic acid alkyl ester monomer, and other polymerizable unsaturated monomers as required, using a known polymerization method such as a solution polymerization method. Can be obtained by polymerization.

  The hydroxyl group-containing polymerizable unsaturated monomer is a compound having a hydroxyl group and a polymerizable unsaturated group. For example, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate (meta) ) Monoesterified products of acrylic acid and diols having 2 to 10 carbon atoms, and ε-caprolactone modified products of these compounds having a hydroxyl group, a (meth) acryloyl group, and a polymerizable unsaturated group.

  Examples of (meth) acrylic acid alkyl ester monomers include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, ( Examples include monoesterified products of (meth) acrylic acid and monoalcohols having 1 to 20 carbon atoms such as (meth) acrylic acid-2-ethylhexyl, (meth) lauryl acrylate, and stearyl (meth) acrylate. it 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 monomer, and examples thereof include (meth) acrylic acid and maleic acid. Examples thereof include carboxyl group-containing polymerizable unsaturated monomers such as: epoxy group-containing polymerizable unsaturated monomers such as glycidyl (meth) acrylate; (meth) acrylamide, acrylonitrile, styrene, vinyl acetate, vinyl chloride and the like.

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

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

  Known phenol resins and polycarbonate resins can be used.

  The coating composition of this invention can contain hardening | curing agents other than a block polyisocyanate compound (D) as needed further. Examples of such curing agents include polyisocyanate compounds and melamine resins.

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

  Typical examples of commercially available polyisocyanate compounds are “Bernock D-750, -800, DN-950, -970 or 15-455” (manufactured by DIC Corporation, trade name, BURNOCK \ Barnock or Burnock). Is a registered trademark), “Death Module L, N, HL, or N3390” (Bayer Aktiengesellschaft), “Semijour N3300, N3390EA” (trade name, manufactured by Sumitomo Chemical Co., Ltd.) SUMIDUR \ Sumijour is a registered trademark) "Takenate D-102, -202, -110 or -123N" (Mitsui Chemicals, trade name, Takenet \ TAKENATE is a registered trademark), "Coronate EH, L, HL or 203 "(Nippon Polyurethane Industry Co., Ltd., trade name, Coronet Doo is a registered trademark) or "Duranate 24A-90CX" (manufactured by Asahi Kasei Co., Ltd., product name, Deyurane - door \DURANATE is a registered trademark) and the like.

  As the melamine resin, an alkyl etherified melamine resin etherified with an alkyl group such as methyl, ethyl, n-butyl, isobutyl, hexyl, 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 800 to 3,000.

  Examples of commercially available products of the melamine resin include butylated melamine resins (Mitsui Toatsu Co., Ltd., Uban 20SE-60, Uban 225, Dainippon Ink Super Becamine G840, Super Becamine G821, etc.), methylated melamine resins ( Mitsui Cyanamid Co., Ltd., Cymel 303, Sumitomo Chemical's Sumimar M-100, Sumimaru M-40S, etc.), methyl etherified melamine resin (Mitsui Cyanamid Co., Ltd. Cymel 303, Cymel 325, Cymel 327, Cymel 350, Cymel 370, Three Nikalac MS17, Nicarak MS15 from Sumika Chemical Co., Ltd., Resimin 741 from Cymont, Summar M55 from Sumitomo Chemical, etc., methylated, butylated mixed etherified melamine resin (Symel 253, Mitsui Cyanamid Co., Ltd.) 02, Cymel 238, Cymel 254, Cymel 272, Cymel 1130, Sumitomo Chemical Sumimar M66B, etc.), methylated, isobutylated mixed etherified melamine resins (Mitsui Cyanamid Co., Ltd., Cymel XV805, Sanwa Chemical Nicarac MS95, etc.), etc. The melamine resin can be used.

  The coating composition of the present invention further contains additives for coatings such as an organic solvent, a silane coupling agent, a curing catalyst, a thickening agent, an antifoaming agent, a surface conditioner, and a film-forming aid, if necessary. can do.

  The organic solvent is not particularly limited as long as it can mix and dissolve or disperse the above-described resin components. For example, aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, alcohol solvents, ester solvents And solvents such as ketone solvents.

  Examples of the silane coupling agent include 2- (3,4 epoxy cyclohexyl) ethyl trialkoxysilane, 3-glycidoxypropyltrialkoxysilane, 3-glycidoxypropylmethyl dialkoxysilane, N-2- (amino Ethyl) -3-aminopropylmethyl dialkoxysilane, N-2- (aminoethyl) -3-aminopropyltrialkoxysilane, 3-aminopropyltrialkoxysilane, 3-aminopropylmethyl dialkoxysilane, 3-mercaptopropyl Methyl dialkoxysilane, 3-mercaptopropyltrialkoxysilane, N-phenyl-3-aminopropyltrialkoxysilane, 3-ureidopropyltrialkoxysilane, 3-chloropropyltrialkoxysilane, bis (trialkoxy) Rirupuropiru) tetrasulfide, 3-isocyanate propyl trialkoxysilane can be exemplified. These can be used alone or in combination of two or more.

  Examples of curing catalysts 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.

Coating material The coating material to which the coating composition of the present invention can be applied is not particularly limited. For example, an outer plate portion of an automobile body such as a passenger car, a truck, a motorcycle, a bus, etc .; an automobile part; a mobile phone Examples of the outer plate portion of household electrical products such as audio equipment can be mentioned. From the point of taking advantage of the characteristics of the coating composition of the present invention having excellent adhesion to both metal materials and plastic materials, metal materials. And an article to be coated containing a plastic material.

  Examples of the metal material include iron, aluminum, brass, copper, tinplate, stainless steel, galvanized steel, and zinc alloy (eg, Zn—Al, Zn—Ni, Zn—Fe, etc.) plated steel.

  The metal material may have a surface subjected to a surface treatment such as a phosphate treatment, a chromate treatment, or a complex oxide treatment, and an undercoat film is formed on the surface of the metal material. May be. Examples of the undercoat paint include electrodeposition paints, and among them, cationic electrodeposition paints are preferable.

  As the plastic material, for example, polyolefins obtained by (co) polymerizing one or more of olefins having 2 to 10 carbon atoms such as ethylene, propylene, butylene and hexene are particularly suitable. , Polycarbonate, ABS resin, urethane resin, polyamide and the like. Examples of molded products made of these plastic materials include automobile outer plate parts such as bumpers, spoilers, grills, and fenders; and outer plate parts of home appliances. Prior to the coating of the coating composition of the present invention, these plastic molded products can be appropriately subjected to degreasing treatment, washing treatment, etc. by a method known per se. Moreover, the coating composition of this invention can be used conveniently also with respect to shaping | molding process materials, such as a film for shaping | molding processes and a sheet | seat for shaping | molding processes containing these plastic materials.

  The coating of the coating composition of the present invention is carried out by applying air spray, airless spray, dip coating, brush, etc., so that the dry film thickness is usually in the range of 1 to 20 μm, preferably 3 to 15 μm. It is suitable to use. After application of the composition, the resulting coated surface can be set at room temperature for about 30 seconds to 60 minutes, if necessary, or about 60 to about 140 ° C, preferably about 70 to about 120 ° C. It can be cured by heating at a temperature for about 20 to 40 minutes.

  In the present invention, the top coating material can be applied to the coating surface of the coating composition of the present invention. As the top-coat paint, a colored paint or a clear paint may be used alone, or a base coat paint and a clear paint may be sequentially applied using the colored paint as a base coat paint. The base coat film by the base coat paint may be one layer or two or more layers. When there are two or more base coat films, the same kind of base coat paint may be applied twice or more, or different base coat paints may be applied repeatedly. In addition, a multilayer film may be formed by sequentially applying, for example, a white base paint and an interference pearl color base paint as a colored base coat film layer on the paint film of the paint composition of the present invention.

  As the colored paint, those known per se can be used. Usually, an organic solvent and / or water as a main solvent, a colored component such as a colored pigment, a bright pigment and a dye, a base resin, a crosslinking agent, etc. The thing containing the resin component of this can be used.

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

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

  The colored paint is a dry film thickness on the coating film of the present uncured or cured present paint composition, usually 5 to 50 μm, preferably 5 to 30 μm, more preferably 10 to 20 μm. The coating surface to be obtained can be set at room temperature for about 1 to 60 minutes, if necessary, or preheated at a temperature of about 40 to about 80 ° C. for about 1 to 60 minutes, 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.

  Examples of the clear paint include a resin component such as a base resin and a crosslinking agent, an organic solvent, water, and the like. Further, if necessary, an ultraviolet absorber, a light stabilizer, a curing catalyst, a coating surface conditioner, An organic solvent-based or water-based thermosetting paint that contains paint additives such as rheology control agents, antioxidants, antifoaming agents, and waxes. It is possible to use one having transparency to the extent that it can be performed.

  Examples of the base resin include acrylic resin, polyester resin, alkyd resin, fluororesin, urethane resin, and 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. In particular, a hydroxyl group-containing acrylic resin is suitable. As said crosslinking agent, it has a reactive functional group which can react with these functional groups, melamine resin, urea resin, (block) polyisocyanate compound, epoxy compound, carboxyl group-containing compound, acid anhydride, alkoxysilane group-containing Examples of the compound include polyisocyanate compounds.

  The clear coating is applied on an uncured or cured colored base coating so that the dry film thickness is usually within the range of 10 to 65 μm, preferably 20 to 60 μm. 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 It can be carried out 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, a coating film having excellent chipping resistance, adhesion and gasoline resistance can be formed on metal materials and plastic materials. The reason why such an excellent coating film can be formed is that the acrylic modified styrenic thermoplastic elastomer (B) has compatibility between the component contributing to adhesion to the metal material and the component contributing to adhesion to the plastic material. It is conceivable to contribute as an improving component. Further, since the acrylic-modified styrene 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 more specifically with reference to examples and comparative examples. However, the present invention is not limited to only these examples. “Part” and “%” are based on mass. Moreover, the film thickness of a coating film is based on a cured coating film.

Preparation Example 1 of Coating Composition
Acrylic modified chlorinated polyolefin (A-1) (Toluene solution of acrylic modified chlorinated polypropylene obtained by grafting methyl methacrylate and the like onto maleic acid modified chlorinated polypropylene having a chlorine content of 17% and a molecular weight of 110,000, acrylic part Tg of 75 ° C., ratio of acrylic part / polyolefin part: 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. , Ratio of acrylic part / SEBS part: 80/20, styrene / (ethylene + butylene) weight ratio of SEBS part = 20/80) 50 parts (solid content), “FLEP-50” (trade name, manufactured by Toray Fine 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 Corporation, active methylene block polyisocyanate compound) 10 parts (solid content), “Ketjen Black EC300J” (trade name, 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 of the mixture was mixed with a mixed solvent of xylene / toluene = 1/1 to obtain a coating composition (X-1) having a viscosity measured at 20 ° C. using Ford Cup # 4 of 13 seconds.

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

  In addition, the mixing | blending of 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, acrylic part Tg: 85 ° C., acrylic part / polyolefin part ratio: 70/30, solid content 20%,
"Supercron 851L" trade name, manufactured by Nippon Paper Industries Co., Ltd., maleic anhydride modified chlorinated polypropylene, chlorination rate 19%, solid content 20%,
“Unistole P-902” (trade name, manufactured by Mitsui Chemicals, hydroxyl group-containing non-chlorinated polyolefin, Mn 5000 or more, hydroxyl value 50 mgKOH / g, solid content 22%,
“KRATON FG1924G” trade name, manufactured by Kraton, acid-modified SEBS, acid value 5 mg CH 3 ONa / g, styrene / (ethylene + butylene) weight ratio = 13/87,
“Tuftec M1943” trade name, manufactured by Asahi Kasei Corporation, acid-modified SEBS, acid value 10 mg CH 3 ONa / g, styrene / (ethylene + butylene) weight ratio = 20/80,
“Tuftec MP10” trade name, manufactured by Asahi Kasei Corporation, amine-modified SEBS, styrene / (ethylene + butylene) weight ratio = 30/70,
“Tuftec H1052” trade name, manufactured by Asahi Kasei Co., Ltd., 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” trade name, manufactured by Nagase ChemteX Corporation, hydrogenated bisphenol A type epoxy resin,
"Baihijoule BL5235" trade name, manufactured by Sumika Covestro Urethane Co., Ltd., 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 Nippon Polychem, 350 mm × 10 mm × 2 mm) was prepared. The surface of the plastic material was degreased by wiping with gauze containing isopropyl alcohol.

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

Test plate 2
As a plastic material, “TSOP-1 (TC-6)” (trade name, manufactured by Nippon Polychem, 350 mm × 10 mm × 2 mm) was prepared. The surface of the plastic material was degreased by wiping with gauze containing isopropyl alcohol.

  The coating compositions (X-1) to (X-22) prepared above were 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”. (Trade name, manufactured by Kansai Paint Co., Ltd., acrylic resin / melamine resin organic solvent type intermediate coating) was electrostatically applied so as to have a dry film thickness of 15 μm.

  After setting for 3 minutes at room temperature, “SOFLEX 420” (trade name, manufactured by Kansai Paint Co., Ltd., solvent-based top coat paint, silver paint color) is electrostatically applied so that the dry film thickness is 15 μm. Painted.

  Next, “Soflex # 500 clear” (trade name, acrylic urethane organic solvent-type clear paint manufactured by Kansai Paint Co., Ltd.) is applied as a clear paint so as to have a dry film thickness of 30 μm. After leaving for a minute, it was heated in an oven at 80 ° C. for 30 minutes to obtain a test coating plate on which a multilayer coating film was formed. Various coating film performance tests described below were conducted on the multilayer coating film.

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

The coating compositions (X-1) to (X-22) prepared above were 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”. (Trade name, manufactured by Kansai Paint Co., Ltd., acrylic resin / melamine resin organic solvent type intermediate coating) was electrostatically applied so as to have a dry film thickness of 15 μm. Next, “SOFLEX 420” (trade name, manufactured by Kansai Paint Co., Ltd., solvent-based overcoat base coat paint, silver paint color) was electrostatically applied so as to have a dry film thickness of 15 μm. Next, “Soflex # 500 clear” (trade name, acrylic urethane organic solvent-type clear paint manufactured by Kansai Paint Co., Ltd.) is applied as a clear paint so as to have a dry film thickness of 30 μm. After leaving for a minute, it was heated in an oven at 80 ° C. for 30 minutes to obtain a test coating plate on which a multilayer coating film was formed. Various coating film performance tests described below were conducted on the multilayer coating film.

Film performance test Chipping resistance: A test coating plate was placed on a specimen holder of a stepping stone testing machine (trade name “QGR GRvelometer” (manufactured by Q Panel Co., Ltd.). 100 g of granite crushed stone of particle size 6 was made to collide with the test plate at an angle of 90 ° with compressed air of 480 to 520 kPa from a distance of 30 cm, and then the obtained test plate was washed with water and dried. A cloth adhesive tape (manufactured by Nichiban Co., Ltd.) was attached, and the tape was peeled off and evaluated based on the area where the electrodeposition surface and the base member were exposed (abbreviated as peeled area).
A: Ratio of peeled area to test coating board area is less than 3% B: Ratio of peeling area to test coating board area is less than 3 to 6% C: Ratio of peeling area to test coating board area is less than 6 to 10% D: Test coating board The ratio of the peeled area to the area is 10% or more.

Water-resistant adhesion: Immerse the test coating plate in warm water at 40 ° C for 240 hours, pull it up and dry it at 20 ° C for 12 hours, then cut the multilayer coating film of the test coating plate into a grid shape with a cutter so as to reach the substrate, Make 100 2mm x 2mm gobangs. Subsequently, an adhesive cellophane tape was attached to the surface, and the remaining state of the goby eye coating 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 Gobang eye coats remain, and no small chipping of the paint film occurs at the cutting edge of the cutter. B: 100 Gobang eye coats remain, but the coating film is small at the cutting edge of the cutter. C: The remaining number of galvanic coatings is 99 to 90.
D: The remaining number of gobang eyes coating is 89 or less.

Moisture resistance adhesion: The test coating plate is allowed to stand in a constant temperature room at 50 ° C. and 95% relative humidity for 240 hours and then at 20 ° C. for 12 hours, so that the multilayer coating film of the test coating plate reaches the substrate. Cut into a grid with a cutter and make 100 gobangs of 2mm x 2mm. Subsequently, an adhesive cellophane tape was stuck on the surface, and the remaining state of the goby eye coating after the tape was rapidly peeled off at 20 ° C. was examined, and the moisture resistance adhesion was evaluated according to the following criteria.
A: 100 Gobang eye coats remain, and no small chipping of the paint film occurs at the cutting edge of the cutter. B: 100 Gobang eye coats remain, but the coating film is small at the cutting edge of the cutter. C: The remaining number of galvanic coatings is 99 to 90.
D: The remaining number of gobang eyes coating is 89 or less.

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

Coating stability: The coating composition prepared above was placed in a 100 mL glass container, and sealed and stored in a container at 35 ° C. for 35 days. The subsequent state was judged according to the following criteria.
A: Good with no change from before storage B: Some layer separation is observed, but returns to the original state when stirred. C: Complete layer separation is observed but returns to the original state when stirred.
D: Layer separation is completely observed and cannot be used as a paint.

Claims (6)

  A coating composition comprising a chlorinated and / or non-chlorinated polyolefin (A), an acrylic-modified styrenic thermoplastic elastomer (B), an epoxy resin (C), a block polyisocyanate compound (D), and a pigment (E). The acrylic-modified styrenic thermoplastic elastomer (B) includes an acrylic part and a styrenic thermoplastic elastomer part,
The glass part transition temperature of the acrylic part of the acrylic modified styrene thermoplastic elastomer (B) is 20 to 100 ° C., and the solid content mass ratio of the acrylic part and the styrene thermoplastic elastomer part is 1: 9 to 9 The coating composition according to claim 1, wherein The coating composition according to claim 1 or 2, wherein the epoxy resin (C) is a polysulfide-modified epoxy resin (C1).   The coating composition according to any one of claims 1 to 3, wherein the block polyisocyanate compound (D) is an active methylene-based block polyisocyanate compound.   A coating method comprising applying a coating composition according to any one of claims 1 to 4 to an object to be coated, and then applying a top coating to the coated surface.   A coating composition according to any one of claims 1 to 4 is applied to an object to be coated, a base coat paint is applied to the uncured coating surface, and a clear coat is applied to the uncured coating surface. A method of painting, including painting and curing a paint.