Carboxyl-containing acrylate copolymer and epoxy resin

• US 5,691,419 A
• Filed: 02/01/1994
• Issued: 11/25/1997
• Est. Priority Date: 06/17/1991
• Status: Expired due to Term

• Current Assignee: BASF AG (BASF SE)
• Original Assignee: BASF AG (BASF SE)
• Inventors: Rotter, Olaf, Engelke, Stephan, Holst, Andreas, Brunnemann, Michael
• Primary Examiner(s): Sellers, Robert E.
• Application Number:
  US08/167,882
• Time in Patent Office: 1,393 Days
• Field of Search: 525/65, 525/108, 525/111, 525/117, 525/118, 525/119, 525/208, 525/209, 525/438
• US Class Current: 525/208
• CPC Class Codes: C08F 290/068 Polysiloxanes
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C08L 2666/14 Macromolecular compounds according to C08L59/00 - C08L87/00; Derivatives thereof
• CPC Class Codes: C09D 151/085 on to polysiloxanes
• CPC Class Codes: C09D 155/005 Homopolymers or copolymers obtained by polymerisation of macromolecular compounds terminated by a carbon-to-carbon double bond
• CPC Class Codes: G09G 3/2018 by time modulation using two or more time intervals

Abstract

A coating agent comprises a binding agentcontaining at least one acrylate copolymer (A) with carboxyl groups and/or at least one acrylate copolymer (B) with epoxide groups, the acrylate copolymers (A) and (B) being obtained by solution polymerization using less than 5% by weight based on the total weight of monomers of one or more polysiloxane macromonomers a₁ having a number-average molecular weight of 1000 to 40,000 and on average 0.5 to 2.5 ethylenically unsaturated double bonds per molecule; and one or more epoxy resins.

Claims

1. A coating agent which comprises, as the binding agent, at least one polymer containing carboxyl groups and, as the hardener, at least one epoxy resin having on average more than one epoxide group per molecule, wherein:

the binding agent comprises at least one acrylate copolymer (A) which comprises carboxyl groups and is prepared by solution polymerization using from 0.4 to 2.5% by weight, based on the total weight of the monomers, of one or more polysiloxane macromonomers a₁ having a number average molecular weight of 1000 to 40,000 and on average 0.5 to 2.5 ethylenically unsaturated double bonds per molecule, wherein copolymer A has a number average molecular weight of between 5000 and 25,000.

2. The coating agent according to claim 1, wherein the acrylate copolymer (A) is prepared using from 0.4 to 1% by weight, based on the total weight of the monomers, of one or more polysiloxane macromonomers A₁.

3. A coating agent according to claim 1, wherein the acrylate copolymer (A) is prepared using one or more polysiloxane macromonomers a₁ which is prepared by reaction of 70 to 99.999 mol % of a compound (1), represented by the formula (I) ##STR7## in which R₁ represents an aliphatic hydrocarbon group with 1 to 8 C atoms or a phenyl radical and R₂, R₃ and R₄ in each case represent a halogen radical or an alkoxy radical having 1 to 4 C atoms or a hydroxyl group, with 30 to 0.001 mol % of a compound (2), represented by the formula (II) ##STR8## in which R₅ represents a hydrogen atom or a methyl radical, R₆, R₇ and R₈ in each case represent halogen, OH or an alkoxy radical having 1 to 4 C atoms or an aliphatic hydrocarbon group having 1 to 8 C atoms, at least one of the radicals R₆, R₇ or R₈ being halogen, OH or an alkoxy group, and n represents an integer from 1 to 6.

4. A coating agent according to claim 1, wherein the acrylate copolymer (A) is prepared using one or more polysiloxane macromonomers a₁ having the formula ##STR9## wherein R₁ =H or CH₃

R₂, R₃, R₄ and R₅ =identical or different aliphatic hydrocarbon radicals having 1 to 8 C atoms, in particular or the phenyl radical,

n=2 to 5, and m=8 to 30.

5. A coating agent according to claim 4, wherein, in the formula for the polysiloxane macromonomers a₁, R₂, R₃, R₄ and R₅ =identical or different aliphatic hydrocarbon radicals selected from the group consisting of the methyl and phenyl radicals, and n=3.

6. A coating agent according to claim 1, wherein the acrylate copolymer (A) containing carboxyl groups is prepared by copolymerization of

a₁) 0.05 to 2.5% by weight, of one or more polysiloxane macromonomers a₁,

a₂) 0 to 40% by weight, of one or more ethylenically unsaturated monomers containing carboxyl groups,

a₃) 0 to 40% by weight, of one or more vinylaromatic hydrocarbons,

a₄) 0 to 99.95% by weight, of one or more ethylenically unsaturated monomers containing hydroxyl groups,

a₅) 0 to 30% by weight, of one or more monomers having at least two polymerizable, ethylenically unsaturated double bonds and

a₆) 0 to 80% by weight of one or more other ethylenically unsaturated copolymerizable monomers, wherein the sum of the parts by weight of components a₁ to a₆ is in each case 100% by weight and wherein the amounts of components a₂ and a₄ employed should not both simultaneously be zero, and when component a₄ is present, the copolymer obtained therewith is reacted with a carboxylic acid anhydride in an amount sufficient to produce a copolymer with an acid number of from 40 to 150 mg of KOH/g.

7. A coating agent according to claim 1, wherein the acrylate copolymer (A) containing carboxyl groups is prepared by copolymerization of

a₁) 0.05 to 0.5% by weight, of one or more polysiloxane macromonomers a₁,

a₂) 0 to 30% by weight, of one or more ethylenically unsaturated monomers containing carboxyl groups,

a₃) 0 to 30% by weight, of one or more vinylaromatic hydrocarbons,

a₄) 20 to 60% by weight, of one or more ethylenically unsaturated monomers containing hydroxyl groups,

a₅) 0 to 20% by weight, of one or more monomers having at least two polymerizable, ethylenically unsaturated double bonds and

a₆) 0 to 80% by weight of one or more other ethylenically unsaturated copolymerizable monomers, wherein the sum of the parts by weight of components a₁ to a₆ is in each case 100% by weight, and wherein the amounts of components a₂ and a₄ employed should not both simultaneously be zero, and when component a₄ is present, the copolymer obtained therewith is reacted with a carboxylic acid anhydride in an amount sufficient to produce a copolymer with an acid number of from 40 to 150 mg of KOH/g.

8. A coating agent according to claim 1, wherein the hardener, is selected from the group consisting of polar epoxides based on a reaction product of melamine resins with acrylamide with subsequent epoxidation of the acrylic double bond.

9. A process for the preparation of the coating agent according to claim 1, comprising the steps of mixing the acrylate copolymer(s) (A) and the epoxy resin(s) with one or more organic solvents to form a first mixture, and then optionally dispersing in the first mixture at least one member selected from the group consisting of pigments, fillers and further additives other than fillers.

10. A process according to claim 9, wherein characterized in that the acrylate copolymer (A) containing carboxyl groups is prepared by solution polymerization at temperatures of between 90°

and 160°

C. using one or more polymerization initiators, by

1.) initially introducing at least 10% by weight of the total amount of the polysiloxane macromonomer a₁ into the reaction vessel and

2.) metering in the other components and any remainder of the polysiloxane macromonomer a₁ which still exists.

11. The process according to claim 10, wherein 100% by weight of the total amount of the polysiloxane macromonomer and optionally at least 60% by weight of the total amount of a vinyl ester of aliphatic monocarboxylic acids which are branched in the α

-position and have 5 to 15 C atoms per molecule are initially introduced into the reaction vessel.

12. A process for coating substrates, wherein a coating agent according to claim 1 is applied.

13. The coating agents according to claim 1, comprising an automotive repair coating composition.

14. The coating agents according to claim 1, comprising a clear coat composition.

15. The coating agents according to claim 1, comprising a clear coat composition for multilayer metallic painting.

16. The coating agents according to claim 1, comprising a top coat coating composition.

17. The coating composition of claim 1, wherein the epoxy resin is an acrylate copolymer which comprises epoxide groups and is prepared by solution polymerization using between 0.05 and 2.5% by weight, based on the total weight of the monomers employed for the preparation of copolymer, of one or more polysiloxane macromonomers a₁ having a number-average molecular weight of 1000 to 40,000 and on average 0.5 to 2.5 ethylenically unsaturated double bonds per molecule, and having a number average molecular weight of between 800 and 2200 and an epoxide equivalent weight of between 250 and 550.

18. A coating agent according to claim 17, wherein characterized in that the acrylate copolymer comprising epoxide groups is prepared using one or more polysiloxane macromonomers a₁ which is prepared by reaction of 70 to 99.999 mol % of a compound (1), represented by the formula (I) ##STR10## in which R₁ represents an aliphatic hydrocarbon group with 1 to 8 C atoms or a phenyl radical and R₂, R₃ and R₄ in each case represent a halogen radical or an alkoxy radical having 1 to 4 C atoms or a hydroxyl group, with 30 to 0.001 mol % of a compound (2), represented by the formula (II). ##STR11## in which R₅ represents a hydrogen atom or a methyl radical, R₆, R₇ and R₈ in each case represent halogen, OH or an alkoxy radical having 1 to 4 C atoms or an aliphatic hydrocarbon group having 1 to 8 C atoms, at least one of the radicals R₆, R₇ or R₈ being halogen, OH or an alkoxy group, and n represents an integer from 1 to 6.

19. A coating agent according to claim 17, wherein characterized in that the acrylate copolymer comprising epoxide groups is prepared using one or more polysiloxane macromonomers a₁ having the formula ##STR12## where R₁ =H or CH₃

R₂, R₃, R₄ and R₅ =identical or different aliphatic hydrocarbon radicals having 1 to 8 C atoms, or the phenyl radical

n=2 to 5,

m=8 to 30.

20. A coating agent according to claim 1, wherein further characterized in that at least one copolymer (A) is prepared by solution polymerization using from 0.4 to less than 1.0% by weight, based on the total weight of monomers employed for the preparation of copolymer (A), of one or more polysiloxane macromonomers a₁.