Process for the production of a multicoat finish, and an aqueous paint

• US 5,334,420 A
• Filed: 09/16/1992
• Issued: 08/02/1994
• Est. Priority Date: 03/30/1990
• Status: Expired due to Term

• Current Assignee: BASF AG (BASF SE)
• Original Assignee: BASF AG (BASF SE)
• Inventors: Grabbe, Michael, Mayenfels, Peter, Hartung, Michael
• Primary Examiner(s): Marquis, Melvyn L.
• Assistant Examiner(s): AYLWARD, DAVID E
• Application Number:
  US07/927,510
• Time in Patent Office: 685 Days
• Field of Search: 523/415, 427/407.1, 427/409, 427/412, 427/412.1, 524/521, 525/63
• US Class Current: 427/407.1
• CPC Class Codes: B05D 2401/20 Aqueous dispersion or solution
• CPC Class Codes: B05D 2401/40 where the carrier is not clearly specified
• CPC Class Codes: B05D 2451/00 Type of carrier, type of coating (Multilayers)
• CPC Class Codes: B05D 7/532 the two layers being cured or baked together, i.e. wet on wet
• CPC Class Codes: C08G 18/0823 containing carboxylate salt groups or groups forming them
• CPC Class Codes: C08G 18/6715 Unsaturated monofunctional alcohols or amines
• CPC Class Codes: C08G 18/675 Low-molecular-weight compounds
• CPC Class Codes: C08G 18/68 Unsaturated polyesters
• CPC Class Codes: C09D 175/14 Polyurethanes having carbon-to-carbon unsaturated bonds
• CPC Class Codes: C09D 175/16 having terminal carbon-to-carbon unsaturated bonds

Abstract

The invention relates to a process for the production of a multicoat finish, in which an aqueous basecoat is used which contains as binder a polymer which can be obtained by polymerizing in an organic solvent

(A) ethylenically unsaturated monomers in the presence of

(B) a polyurethane resin containing polymerizable double bonds

and converting the resultant reaction product to an aqueous dispersion.

Claims

1. A process for the production of a multicoat finish on a substrate surface, in which

(1) a pigmented aqueous basecoat is applied to the substrate surface,

(2) a polymer film is formed from the composition applied in stage (1),

(3) a transparent topcoat is applied to the basecoat obtained in this way and subsequently

(4) the basecoat is baked together with the topcoat, wherein the basecoat comprises as binder a polymer which can be obtained by polymerizing in an organic solvent or in a mixture of organic solvents

(A) ethylenically unsaturated monomers or a mixture of ethylenically unsaturated monomers in the presence of

(B) a polyurethane resin which has a number average molecular weight of 200 to 30,000, preferably of 1,000 to 5,000, and which contains on a statistical average 0.05 to 1.1, preferably 0.2 to 0.9, particularly preferably 0.3 to 0.7 polymerizable double bonds per molecule,

and converting the reaction product obtained in this way to an anionically stabilized aqueous dispersion.

2. The process as claimed in claim 1 wherein the polymer prepared from (A) and (B) has an acid value of 5 to 200, preferably of 10 to 40, particularly preferably of 15 to 30, a hydroxyl value of 0 to 100, preferably of 20 to 80, and a number average molecular weight of 2,000 to 20,000, preferably of 5,000 to 12,000.

3. The process as claimed in claim 1 wherein the polymer prepared from (A) and (B) has a molecular wight distribution Q=M_w :

M_n of 5 to 90, preferably of 10 to 30.

4. The process as claimed in claim 1 wherein the polymer can be obtained by using the components (A) and (B) in a weight ration of 1:

10 to 10;

1, preferably 1;

2 to 2;

1, particularly preferably 1;

1.

5. The process as claimed in claim 1 wherein the polyurethane resin which contains polymerizable double bonds, introduced into the molecules of the polyurethane resin by incorporation of compounds which contain, in addition to a polymerizable double bond, at least two groups reactive toward NCO groups, is used as the component (B).

6. The process as claimed in claim 1 wherein the polyurethane resin which contains allyl ether groups as polymerizable double bonds is used as the component (B).

7. The process as claimed in claim 1 wherein the polyurethane resin which has trimethylolpropane monoallyl ether incorporated is used as the component (B).

8. The process as claimed in claim 1 wherein the polymer can be obtained by using as the component (B) a polyurethane resin which has an acid value of 0 to 2.0.

9. An aqueous paint which contains as binder a polymer which can be obtained by polymerizing in an organic solvent or in a mixture of organic solvents

(A) ethylenically unsaturated monomers or a mixture of ethylenically unsaturated monomers in the presence of

(B) a polyurethane resin which has a number average molecular weight of 200 to 30,000, preferably of 1,000 to 5,000, and which contains on statistical average 0.05 to 1.1, preferably 0.2 to 0.9, particularly preferably 0.3 to 0.7 polymerizable double bonds per molecule

and converting the reaction product obtained in this way to an anionically stabilized aqueous dispersion.

10. The paint as claimed in claim 9, wherein the polymer prepared from (A) and (B) has an acid value of 5 to 200, preferably of 10 to 40, particularly preferably of 15 to 30, a hydroxyl value of 0 to 100, preferably of 20 to 80, and a number average molecular weight of 2,000 to 20,000, preferably of 5,000 to 12,000.

11. The paint as claimed in claim 9 wherein the polymer prepared from (A) and (B) has a molecular weight distribution Q=M_W :

M_n of 5 to 90, preferably of 10 to 30.

12. The paint as claimed in claim 9 wherein the polymer can be obtained by using the components (A) and (B) in a weight ratio of 1:

10 to 10;

1, preferably 1;

2 to 2;

1, particularly preferably 1;

1.

13. The paint as claimed in claim 9, wherein a polyurethane resin which contains polymerizable double bonds, introduced into the molecules of the polyurethane resin by incorporation of compounds which contains, in addition to a polymerizable double bond, at least two groups reactive toward NCO groups, is used as the component (B).

14. The paint as claimed in claim 9 wherein the polyurethane resin which contains allyl ether groups as polymerizable double bonds is used as the component (B).

15. The paint as claimed in claim 9 wherein the polyurethane resin which has trimethylolpropane monoallyl ether incorporated is used as the component (B).

16. The paint as claimed in claim 9 wherein the polymer can be obtained by using as the component (B) a polyurethane resin which has an acid value of 0 to 2.0.