Claims
- 1. A coating composition applied to a substrate comprising an alkyd resin based topcoat and a water-dilutable coating for the production of a heat-curable coating containing a binder comprising an epoxide resin-modified, water-dilutable polyester produced by the reaction of:
- (A) a polyester having a number average molecular weight of less than 2000, an acid number of from 35 to 240, and an OH number of from 56 to 320, prepared by the reaction of:
- (a.sub.1) a polycarboxylic acid containing at least three carboxyl groups, or a derivative thereof;
- (a.sub.2) a polyol containing at least one carboxyl group other than components (a.sub.1), (a.sub.3) and (a.sub.4);
- (a.sub.3) a polycarboxylic acid containing two carboxyl groups, or a reactive derivative thereof, other than component (a.sub.2), and
- (a.sub.4) a polyol other than component (a.sub.2),
- such that at least 10 mol % of the sum of components (a.sub.1), (a.sub.2), (a.sub.3) and (a.sub.4) contains at least one (cyclo)aliphatic structural element having at least six carbon atoms, and wherein the (a.sub.1) and (a.sub.3) components are co-condensed via at least two carboxyl groups, and
- (B) from 0.3 to 1.5 equivalents per polyester molecule of an epoxide resin based on a bisphenol and having an epoxide equivalent weight of from 170 to 1,000, or a derivative thereof having at least one epoxide group per molecule,
- said reaction conducted under conditions in which essentially only carboxyl groups react with epoxide groups to produce an epoxide resin-modified polyester which is water-dilutable after at least part of the free carboxyl groups are neutralized.
- 2. A coating composition according to claim 1 wherein from 30 to 70 mol % of the sum of polyester components (a.sub.1), (a.sub.2), (a.sub.3) and (a.sub.4) contains at least one (cyclo)aliphatic structural element having at least 6 carbon atoms.
- 3. A coating composition according to claim 1 wherein polyester (A) has a number average molecular weight of from 500 to 1,500.
- 4. A coating composition according to claim 1 wherein polyester (A) has an acid number of from 50 to 120.
- 5. A coating composition according to claim 1 wherein polyester (A) is reacted with 0.5 to 1.5 equivalents of epoxide resin (B) per polyester molecule.
- 6. A coating composition according to claim 1 wherein epoxide resin (B) has an epoxide equivalent weight of from 170 to 500.
- 7. A coating composition according to claim 1 wherein epoxide resin (B) is a bisphenol A-based epoxide resin.
- 8. A coating composition according to claim 1 wherein (a.sub.1) or (a.sub.3) comprises at least one polymeric fatty acid.
- 9. A coating composition according to claim 8 wherein the polymeric fatty acid is a dimeric fatty acid.
- 10. A coating composition according to claim 1 further comprising a pigment.
- 11. A coating composition according to claim 1 further comprising water.
- 12. A coating composition according to claim 1 wherein polyester (A) is reacted with 0.3 to 1.5 equivalents per polyester molecule of a reaction product containing at least one epoxide group per molecule and formed from an epoxide resin based on a bisphenol having an epoxide equivalent weight of from 170 to 500 and a monocarboxylic or polycarboxylic acid having a (cyclo)aliphatic structural element containing at least 6 carbon atoms.
- 13. A coating composition according to claim 12 wherein polyester (A) is reacted with 0.3 to 1.5 equivalents per polyester molecule of a reaction product containing at least one epoxide group per molecule and formed from an epoxide resin based on a bisphenol and a monocarboxylic or polycarboxylic acid having a (cyclo)aliphatic structural element containing at least 6 carbon atoms.
- 14. A coating composition according to claim 1 wherein the alkyd resin of the topcoat is derived from saturated and unsaturated fatty acids and the topcoat further contains a melamine resin partially etherified with n-butanol.
- 15. A coating composition according to claim 14 wherein the topcoat is pigmented.
Priority Claims (2)
Number |
Date |
Country |
Kind |
36 36 368.5 |
Oct 1986 |
DEX |
|
PCT/EP87/00624 |
Oct 1987 |
WOX |
|
Parent Case Info
This application is a division of application Ser. No. 08/132,003, filed on Oct. 5, 1993, now U.S. Pat. No. 5,380,565, which is a division of application Ser. No. 07/964,169 filed Oct. 21, 1992, now U.S. Pat. No. 5,272,187, which is a continuation of application Ser. No. 07/617,459 filed Nov. 21, 1990, now U.S. Pat. No. 5,183,835, which is a continuation of application Ser. No. 07/350,626 filed Apr. 25, 1989, now abandoned.
US Referenced Citations (5)
Foreign Referenced Citations (7)
Number |
Date |
Country |
0077023 |
Apr 1983 |
EPX |
2309596 |
Nov 1976 |
FRX |
2377434 |
Aug 1978 |
FRX |
53-90334 |
Aug 1978 |
JPX |
61-43664 |
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JPX |
1275768 |
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GBX |
1558303 |
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GBX |
Divisions (2)
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Number |
Date |
Country |
Parent |
132003 |
Oct 1993 |
|
Parent |
964169 |
Oct 1992 |
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Continuations (2)
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Number |
Date |
Country |
Parent |
617459 |
Nov 1990 |
|
Parent |
350626 |
Apr 1989 |
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