Coating composition and method for forming multi-layer coating
First Claim
1. A method of forming a multi-layer coating comprising the steps of applying a base coat composition to an article to be coated, applying a topcoat to the resultant base coat, and separately or simultaneously baking the resultant coats, wherein(A) said topcoat composition contains (a) a blend of at least one compound having a plurality of hydrosilyl groups and at least one compound having a plurality of alkenyl groups and (b) a catalytic amount of hydrosilylation catalyst,there being a sufficient amount of said at least one compound having a plurality of hydrosilyl groups which contain phosphoric groups and/or said at least one compound having a plurality of alkenyl groups which contain phosphoric groups to provide an amount of phosphoric groups in said topcoat composition of from 0.001-5 mol/kg on a solid basis based on said compounds in said blend,said at least one compound having a plurality of hydrosilyl groups being selected from the group consisting of (1) an organo-hydrogen polysiloxane having at least two hydrosilyl groups in one molecule represented by the following general formula:
- ##STR26## wherein R1 is an alkyl group having 1-6 carbon atoms, a phenyl group or a phenethyl group, R2 is a hydrogen atom, an alkyl group having 1-6 carbon atoms, a phenyl group or a phenethyl group, and a is a number of 2-200, and (2) a homopolymer or a copolymer which does not contain alkenyl groups of a hydrogen polysiloxane macromonomer having a structural unit represented by the following general formula;
##STR27## wherein R1 is an alkyl group having 1-6 carbon atoms, a phenyl group or a phenethyl group, R2 is a hydrogen atom, an alkyl group having 1-6 carbon atoms, a phenyl group or a phenethyl group and b is a number of 1-30, said structural unit further having at least one hydrosilyl group in one molecule and at least one (meth)acryloyloxyalkylene group in a siloxane skeleton or ends thereof, andsaid at least one compound having a plurality of alkenyl groups being selected from the group consisting of alkenyl group-containing polyether resins, alkenyl group-containing acrylic resins, alkenyl group-containing polyester resins, alkenyl group-containing polycarbonate resins and alkenyl group-containing epoxy resins; and
(B) said base coat composition containing (d) a cross-linking agent which does not interfere with the hydrosilylation reaction of said topcoat composition and being selected from the group consisting of amino resins, blocked polyisocyanate compounds and curing agents for epoxy resins, and (e) a functional resin reactable with said cross-linking agent which is at least one resin selected from the group consisting of acrylic resins, polyester resins and epoxy resins, which functional resin is organic solvent-borne or aqueous-borne.
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Abstract
A multi-layer coating comprising a base coat and a topcoat is formed on an article such as a chemically-treated steel plate by coating the article with a base coat composition containing (a) a cross-linking agent which does not interfere with the hydrosilylation reaction of a topcoat composition, and (b) a functional resin reactable with the cross-linking agent, and then with a topcoat composition containing (c) (i) a blend of a hydrosilyl group-containing compound and an alkenyl group-containing compound, and/or (ii) a self-crosslinkable resin, and (d) a catalytic amount of a hydrosilylation catalyst, followed by separate or simultaneous baking. The topcoat composition may contain functional groups (phosphoric groups and/or alkoxysilyl groups) or a functional group-containing compound.
74 Citations
20 Claims
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1. A method of forming a multi-layer coating comprising the steps of applying a base coat composition to an article to be coated, applying a topcoat to the resultant base coat, and separately or simultaneously baking the resultant coats, wherein
(A) said topcoat composition contains (a) a blend of at least one compound having a plurality of hydrosilyl groups and at least one compound having a plurality of alkenyl groups and (b) a catalytic amount of hydrosilylation catalyst, there being a sufficient amount of said at least one compound having a plurality of hydrosilyl groups which contain phosphoric groups and/or said at least one compound having a plurality of alkenyl groups which contain phosphoric groups to provide an amount of phosphoric groups in said topcoat composition of from 0.001-5 mol/kg on a solid basis based on said compounds in said blend, said at least one compound having a plurality of hydrosilyl groups being selected from the group consisting of (1) an organo-hydrogen polysiloxane having at least two hydrosilyl groups in one molecule represented by the following general formula: - ##STR26## wherein R1 is an alkyl group having 1-6 carbon atoms, a phenyl group or a phenethyl group, R2 is a hydrogen atom, an alkyl group having 1-6 carbon atoms, a phenyl group or a phenethyl group, and a is a number of 2-200, and (2) a homopolymer or a copolymer which does not contain alkenyl groups of a hydrogen polysiloxane macromonomer having a structural unit represented by the following general formula;
##STR27## wherein R1 is an alkyl group having 1-6 carbon atoms, a phenyl group or a phenethyl group, R2 is a hydrogen atom, an alkyl group having 1-6 carbon atoms, a phenyl group or a phenethyl group and b is a number of 1-30, said structural unit further having at least one hydrosilyl group in one molecule and at least one (meth)acryloyloxyalkylene group in a siloxane skeleton or ends thereof, andsaid at least one compound having a plurality of alkenyl groups being selected from the group consisting of alkenyl group-containing polyether resins, alkenyl group-containing acrylic resins, alkenyl group-containing polyester resins, alkenyl group-containing polycarbonate resins and alkenyl group-containing epoxy resins; and (B) said base coat composition containing (d) a cross-linking agent which does not interfere with the hydrosilylation reaction of said topcoat composition and being selected from the group consisting of amino resins, blocked polyisocyanate compounds and curing agents for epoxy resins, and (e) a functional resin reactable with said cross-linking agent which is at least one resin selected from the group consisting of acrylic resins, polyester resins and epoxy resins, which functional resin is organic solvent-borne or aqueous-borne. - View Dependent Claims (2, 3, 4, 5, 6)
- ##STR26## wherein R1 is an alkyl group having 1-6 carbon atoms, a phenyl group or a phenethyl group, R2 is a hydrogen atom, an alkyl group having 1-6 carbon atoms, a phenyl group or a phenethyl group, and a is a number of 2-200, and (2) a homopolymer or a copolymer which does not contain alkenyl groups of a hydrogen polysiloxane macromonomer having a structural unit represented by the following general formula;
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7. A method for forming a multi-layer coating comprising the steps of applying a base coat composition to an article to be coated, applying a topcoat to the resultant base coat, and separately or simultaneously baking the resultant coats, wherein
(A) said topcoat composition contains (a) a blend of at least one compound having a plurality of hydrosilyl groups and at least one compound having a plurality of alkenyl groups, (b) a catalytic amount of a hydrosilylation catalyst and (c) at least one compound selected from the group consisting of phosphoric acid and phosphates in an amount of 0.05-30 parts by weight on the basis of 100 parts by weight of solid resin components in the topcoat composition, said at least one compound having a plurality of hydrosilyl groups being selected from the group consisting of (1) an organo-hydrogen polysiloxane having at least two hydrosilyl groups in one molecule and represented by the following general formula: - ##STR28## wherein R1 is an alkyl group having 1-6 carbon atoms, a phenyl group or a phenethyl group, R2 is a hydrogen atom, an alkyl group having 1-6 carbon atoms, a phenyl group or a phenethyl group, and a is a number of 2-200, and (2) a homopolymer or a copolymer which does not contain alkenyl groups of a hydrogen polysiloxane macromonomer having a structural unit represented by the following general formula;
##STR29## wherein R1 is an alkyl group having 1-6 carbon atoms, a phenyl group or a phenethyl group, R2 is a hydrogen atom, an alkyl group having 1-6 carbon atoms, a phenyl group or a phenethyl group and b is a number of 1-30, said structural unit further having at least one hydrosilyl group in the molecule and at least one (meth)acryloyloxyalkylene group in a siloxane skeleton or ends thereof, andsaid compound having a plurality of alkenyl groups being selected from the group consisting of alkenyl group-containing polyether resins, alkenyl group-containing acrylic resins, alkenyl group-containing polyester resins, alkenyl group-containing polycarbonate resins and alkenyl group-containing epoxy resins; and (B) said base coat composition containing (d) a cross-linking agent which does not interfere with a hydrosilylation reaction of said topcoat composition and being selected from the group consisting of amino resins,m blocked polyisocyanate compounds and curing agents for epoxy resins, and (e) a functional resin reactable with said cross-linking agent which is at least one resin selected from the group consisting of acrylic resins, polyester resins and epoxy resins, which functional resin is solvent-borne or aqueous-borne. - View Dependent Claims (8, 9, 10)
- ##STR28## wherein R1 is an alkyl group having 1-6 carbon atoms, a phenyl group or a phenethyl group, R2 is a hydrogen atom, an alkyl group having 1-6 carbon atoms, a phenyl group or a phenethyl group, and a is a number of 2-200, and (2) a homopolymer or a copolymer which does not contain alkenyl groups of a hydrogen polysiloxane macromonomer having a structural unit represented by the following general formula;
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11. A method for forming a multi-layer coating comprising the steps of applying a base coat composition to an article to be coated, applying a topcoat to the resultant base coat, and separately or simultaneously baking the resultant coats, wherein
(A) said topcoat composition contains (a) at least one compound having a plurality of hydrosilyl groups and a plurality of alkenyl groups and (b) a catalytic amount of hydrosilylation catalyst, said at least one compound being a copolymer of: -
(1) a hydrogen polysiloxane macromonomer having a structural unit represented by the following general formula;
##STR33## wherein R1 is an alkyl group having 1-6 carbon atoms, a phenyl group or a phenethyl group, R2 is a hydrogen atom, an alkyl group having 1-6 carbon atoms, a phenyl group or a phenethyl group, and b is a number of 1-30, said structural unit having at least one hydrosilyl group in one molecule, and further having at least one (meth)acryloyloxy alkylene group in a siloxane skeleton or ends thereof, and(2) an alkenyl group-containing acrylic monomer; and (B) said base coat composition containing (d) a cross-linking agent which does not interfere with a hydrosilylation reaction of said topcoat composition and being selected from the group consisting of amino resins, blocked polyisocyanate compounds and curing agents for epoxy resins, and (e) a functional resin reactable with said cross-linking agent which is at least one resin selected from the group consisting of acrylic resins, polyester resins, epoxy resins, which functional resin is solvent-borne or aqueous-borne. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification