Water-dispersible coating compositions and process

• US 4,511,682 A
• Filed: 05/29/1984
• Issued: 04/16/1985
• Est. Priority Date: 06/28/1983
• Status: Expired due to Term

• Current Assignee: Union Carbide Corporation Old Ridgebury Road Danbury CT 06817
• Original Assignee: Union Carbide Corporation (Dow, Inc.)
• Inventors: Burns, Richard J., Mayer, Walter P.
• Primary Examiner(s): GRIFFIN, RONALD
• Application Number:
  US06/614,799
• Time in Patent Office: 322 Days
• Field of Search: 525/109, 525/110, 525/117, 525/119, 525/170, 525/185, 523/501, 523/202, 523/402, 523/423, 524/505, 524/539, 524/590
• US Class Current: 523/402
• CPC Class Codes: C08G 81/021 Block or graft polymers containing only sequences of polymers of C08C or C08F
• 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: C09D 127/06 Homopolymers or copolymers of vinyl chloride
• CPC Class Codes: C09D 131/04 Homopolymers or copolymers of vinyl acetate
• CPC Class Codes: C09D 135/02 Homopolymers or copolymers of esters C09D135/06, C09D135/08 take precedence
• CPC Class Codes: C09D 187/005 Block or graft polymers not provided for in groups C09D101/00 - C09D185/04

Abstract

Stable, water-dispersible block copolymer coating compositions are produced from water-indispersible organic polymers having a plurality of hydroxyl groups and water-dispersible organic polymer having a plurality of carboxylic acid anhydride groups by controlled esterification.

Claims

1. A process for preparing water-dispersible, block copolymer coating compositions, which process comprises:

(1) forming a reaction mixture comprising (i) a water-indispersible, film-forming, organic polymer having an average of at least three hydroxyl groups per molecule (hereinafter referred to as "Reactant A"), (ii) an organic polymer, other than an ethylene-maleic anhydride copolymer, which has an average of at least two carboxylic acid anhydride groups per molecule and which, after hydrolysis and neutralization of at least some of the anhydride groups with a base, is dispersible in water, (hereinafter referred to as "Reactant B"), and (iii) an esterification catalyst;

(2) reacting hydroxyl groups of Reactant A and anhydride groups of Reactant B to form ester groups and carboxy groups, such reaction being conducted to the extent necessary to produce a film-forming composition which, after neutralization of at least some of the carboxy groups with a base, is dispersible in a primarily aqueous medium having a pH over 5; and

(3) controlling said reaction to prevent gelation of the composition by incorporating in said reaction mixture water or a low molecular weight organic compound containing one or two groups reactive with said anhydride groups.

2. A process as claimed in claim 1 wherein the reaction mixture also contains an organic solvent and the product in said composition is dissolved in said solvent to form a varnish.

3. A process as claimed in claim 2 wherein the organic solvent is a water soluble dialkyl ketone.

4. A process as claimed in claim 1 wherein Reactant A is a vinyl chloride/vinyl acetate/hydroxyalkyl acrylate terpolymer having 2 to about 6 carbons in the hydroxyalkyl moiety.

5. A process as claimed in claim 1 wherein Reactant B is a styrene/maleic anhydride copolymer.

6. A process as claimed in claim 2 wherein the organic solvent is partially stripped from the varnish and exchanged for a monoalkyl glycol ether having 1 to about 6 carbons in the alkyl moiety.

7. A process as claimed in claim 6 wherein the stripped organic solvent is acetone and the monoalkyl glycol ether is monobutyl ether of ethylene glycol.

8. A process as claimed in claim 1 wherein the catalyst is a trialkylamine having 1 to about 4 carbons in the alkyl moiety.

9. A process as claimed in claim 2 wherein the block copolymer varnish is contacted with an aqueous solution containing a base and an organic solvent whereby a stable aqueous dispersion is obtained.

10. A process as claimed in claim 9 wherein the base is dimethylethanolamine and the organic solvent is an alkyl glycol ether having 2 to about 4 carbons in the alkyl moiety.

11. A process as claimed in claim 9 wherein the aqueous dispersion is mixed with a water-soluble crosslinking agent.

12. A process as claimed in claim 11 wherein the crosslinking agent is hexamethoxymethylmelamine.

13. A process as claimed in claim 1 wherein the reaction is controlled to prevent gelation by incorporating water in said reaction mixture.

14. A process as claimed in claim 1 wherein the reaction is controlled to prevent gelation by incorporating in the reaction mixture a low molecular weight organic compound having a molecular weight no greater than 200.

15. A process as claimed in claim 1 wherein the reaction is controlled to prevent gelation by incorporating in the reaction mixture a low molecular weight organic compound having a molecular weight no greater than 120.

16. A process as claimed in claim 1 wherein the reaction is controlled to prevent gelation by incorporating in the reaction mixture a monohydric alcohol.

49. A process as claimed in claim 1 wherein Reactant I and Component I form basic aqueous dispersions wherein the dispersed particles have an average particle size greater than five microns or more than ten percent by weight of Reactant I or Component I is filtered out with a 325 mesh screen and wherein Reactant II, Component II and the block copolymer coating composition form a basic solution wherein the dispersed particles have an average particle size less than five microns and less than ten percent by weight of the salt formed from Reactant B, Component II or the composition is filtered out with a 325 mesh screen.

50. A process as claimed in claim 1 wherein Reactant A is a vinyl chloride/vinyl acetate/vinyl alcohol terpolymer.

51. A process as claimed in claim 1 wherein Reactant A is a vinyl chloride/vinyl acetate/vinyl alcohol/maleic acid quadripolymer.

17. A block copolymer coating composition comprising:

(A) a water-indispersible, film-forming, organic polymer component having an average of at least three hydroxyl groups per molecule (hereinafter referred to as "Component I") and

(B) an organic polymer component, other than a component derived from an ethylene-maleic anhydride copolymer, which has an average of at least two carboxylic acid groups per molecule and which, after neutralization of at least some of the carboxy groups with a base, is dispersible in water (hereinafter referred to as "Component II"),

said composition;

(a) containing an average of from 0.1 to 3.1 ester group(s) per mole of Component I, which ester group(s) link at least some of Component I to at least some of Component II; and

(b) being dispersible in a primarily aqueous medium having a pH over 5 after neutralization of at least some of the carboxy groups with a base.

18. A composition as claimed in claim 17 wherein Component I is a hydrophilic addition polymer having a number average molecular weight from 500 to 35,000 or 50,000.

19. A composition as claimed in claim 17 wherein Component I is a hydrophilic addition polymer having a number average molecular weight from 3,000 to 35,000 or 50,000.

20. A composition as claimed in claim 17 wherein Component I is a hydrophobic addition polymer having a number average molecular weight from 500 to 20,000.

21. A composition as claimed in claim 17 wherein Component I is a hydrophobic addition polymer having a number average molecular weight from 3,000 to 15,000.

22. A composition as claimed in claim 17 wherein Component I is an epoxy polymer or a phenoxy polymer having a number average molecular weight from 500 to 50,000.

23. A composition as claimed in claim 17 wherein Component I is an epoxy polymer or a phenoxy polymer having a number average molecular weight from 3,000 to 40,000.

24. A composition as claimed in claim 17 wherein Component II has a number average molecular weight from 300 to 30,000.

25. A composition as claimed in claim 17 wherein Component II has a number average molecular weight from 800 to 2,500.

26. A solution comprising a composition as claimed in claim 17 and a solvent therefor selected from the group consisting of ketone, hydrocarbons, esters and chlorinated hydrocarbons.

27. A solution comprising a composition as claimed in claim 17 and a solvent therefor selected from the group consisting of acetone, methylethyl ketone, ethylpropyl ketone, methylbutyl ketone and ethylbutyl ketone.

28. A solution comprising a composition as claimed in claim 17 and a solvent therefor selected from the group consisting of glycols and ethers.

29. A solution comprising a composition as claimed in claim 17 and a solvent therefor selected from the group consisting of monobutylethylene glycol, monopropylethylene glycol, monoethylethylene glycol, monomethylethylene glycol, monomethyldiethylene glycol and monoethyldiethylene glycol.

30. A composition as claimed in claim 17 containing an average of from 0.5 to 2 ester groups per molecule of Component I.

31. A water-dispersible salt-containing coating composition, which composition is a block copolymer composition comprising:

(A) a water-dispersible, film-forming, organic polymer component having an average of at least three hydroxyl groups per molecule (hereinafter referred to as "Component I"), and

(B) a water-dispersible organic polymer component, other than a component derived from an ethylene-maleic anhydride copolymer, which has an average per molecule of at least two salt groups derived from carboxylic acid groups and a base (hereinafter referred to as "Component II"),

said composition containing an average of from 0.1 to 3.1 ester group(s) per mole of Component I, which ester group(s) link at least some of Component I to at least some of Component II.

32. An aqueous dispersion comprising a major amount of water and minor amount of a salt-containing coating composition as claimed in claim 31.

33. An aqueous dispersion comprising a major amount of water, a minor amount of composition as claimed in claim 31 and a minor amount of an organic solvent for said compositions.

34. An aqueous dispersion containing from 15 to 55 weight percent of a composition as claimed in claim 31, from 40 to 84 weight percent of water and from 0 to 35 weight percent of an organic solvent for said composition.

35. An aqueous dispersion containing from 20 to 35 weight percent of a composition as claimed in claim 31, from 50 to 70 weight percent of water and from 5 to 25 weight percent of an organic solvent for said composition.

36. A curable mixture comprising a composition as claimed in claim 31 and a cross-linking agent.

37. A curable mixture as claimed in claim 36 wherein the cross-linking agent is a melamine-formaldehyde resin, a urea-formaldehyde resin or a polyaziridine resin.

38. A curable mixture that is an aqueous dispersion comprising a major amount of water and minor amounts of a composition as claimed in claim 31 and a cross-linking agent.

39. A curable mixture that is an aqueous dispersion comprising a major amount of water and minor amounts of a composition as claimed in claim 31, a cross-linking agent for said composition and an organic solvent for said composition.

40. A solid substrate coated with a coating produced thereon by curing a mixture as claimed in claim 36.

41. A solid substrate as claimed in claim 40 where the substrate is a metal.

42. A process for coating solid substrate which comprises applying to the substrate a film of a curable mixture as defined in claim 36 and curing said mixture on said substrate.

43. A dispersion as claimed in claim 32 wherein the dispersed particles have an average particle size less than 5 microns and less than ten percent by weight of the salt-containing coating composition is filtered out with a 325 mesh screen.

44. An aqueous dispersion as claimed in claim 32 wherein the dispersed particles have an average particle size less than one micron and less than two percent by weight of the salt-containing composition is filtered out with a 325 mesh screen.

45. A dispersion as claimed in claim 32 wherein the dispersed particles have an average particle size less than five microns and less than ten percent by weight of the salt-containing coating composition is filtered out with a 325 mesh screen.

46. An aqueous dispersion as claimed in claim 32 wherein the dispersed particles have an average particle size less than one micron and less than two percent by weight of the salt-containing composition is filtered out with a 325 mesh screen.

47. A dispersion as claimed in claim 32 having a pH from six to nine.

48. A dispersion as claimed in claim 32 having a pH from seven to eight.