Barrier coat for open tool molding

• US 20040038059A1
• Filed: 06/20/2003
• Published: 02/26/2004
• Est. Priority Date: 08/01/2002
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Kia, Hamid G., Mitchell, Harry A., Wathen, Terrence J., Buffa, Mark A.
• Granted Patent: US 7,226,665 B2
• Time in Patent Office: Days
• US Class Current: 428/515
• CPC Class Codes: B29C 70/003 characterised by the matrix material, e.g. material composition or physical properties
• CPC Class Codes: B29C 70/025 with particular filler
• CPC Class Codes: B29C 70/30 Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core
• CPC Class Codes: B29C 70/305 Spray-up of reinforcing fibres with or without matrix to form a non-coherent mat in or on a mould B29C41/365, B29C70/32, B29C70/34, B29C70/502, B29C70/508 take precedence; coating a former by spraying plastics B29C41/08
• CPC Class Codes: B32B 17/04 bonded with or embedded in a plastic substance
• CPC Class Codes: B32B 27/00 Layered products comprising a layer of synthetic resin fibrous or filamentary layer made of a synthetic resin B32B5/02; particulate layer made of a synthetic resin B32B5/16; foamed layer made of a synthetic resin B32B5/18
• CPC Class Codes: B32B 27/12 next to a fibrous or filamentary layer
• CPC Class Codes: B32B 27/40 comprising polyurethanes
• CPC Class Codes: B32B 5/26 another layer next to it also being fibrous or filamentary relative arrangement of fibres or filaments of different layers B32B5/12
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/31565 Next to polyester [polyethylene terephthalate, etc.]
• CPC Class Codes: Y10T 428/31794 Of cross-linked polyester
• CPC Class Codes: Y10T 428/31855 Of addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31909 Next to second addition polymer from unsaturated monomers

Abstract

A multilayer composite contains a gel coat layer, a laminate layer, and a barrier layer disposed between the gel coat and the laminate layer. The laminate contains from 40-80% by weight paste and from 20-60% by weight reinforcing fibers. The barrier coat also comprises a cured polyester resin, and contains reinforcing fibers shorter than those in the laminate layer. The barrier layer has sufficient flexibility to avoid cracking during demolding and handling. Preferably, the barrier layer exhibits an elongation at break of more than 1%, and more preferably about 2% or more. The resin of the barrier layer can contain up to about 25% by weight of the resin of an isophthalic acid based polyester resin. The composites can be made using an open tool molding process.

Claims

1. A multilayer composite article comprising:

a gel coat layer comprising a thermosetting resin;

a fiber reinforced laminate layer comprising first fibers having a first length; and

a barrier layer disposed between the gel coat layer and the laminate layer;

wherein the barrier layer comprises second fibers dispersed in a polyester resin, said second fibers having a second length shorter than the first length.

2. A multilayer composite according to claim 1, wherein the polyester resin comprises up to 25% of an isophthalic acid resin, based on the total weight of the polyester resin.

3. A multilayer composite according to claim 1, wherein the polyester resin comprises 75-100% by weight of a dicyclopentadiene resin, based on the total weight of the polyester resin.

4. A multilayer composite according to claim 1, wherein the polyester resin comprises 75-99% by weight dicyclopentadiene resin and 1-25% by weight isophthalic resin.

5. A multilayer composite according to claim 1, wherein the second length is 1 mm or less.

6. A multilayer composite according to claim 1, wherein the second length is 0.5 mm or less.

7. A multilayer composite according to claim 1, wherein the second length is 0.4 mm or less.

8. A multilayer composite according to claim 1, wherein the gel coat is ½

-2 mm thick, the barrier coat is 1-3 mm thick, and the laminate layer is 2-5 mm thick.

9. A multilayer composite according to claim 1, wherein the barrier coat comprises up to 45% by weight milled glass fibers of length less than 1 mm and 50-95% by weight resin comprising dicyclopentadiene resin and isophthalic acid ratio in a ratio of at least 4:

1.

10. A multilayer composite according to claim 1, wherein the barrier coat further comprises polymeric hollow microspheres.

11. An automotive body panel comprising:

a gel coat layer;

a laminate layer; and

a barrier coat disposed between the gel coat and the laminate layer,

wherein the barrier coat comprises a polyester resin and reinforcing fibers of length 1 mm or less.

12. A body panel according to claim 11, wherein the barrier coat exhibits an elongation at break of at least 1%.

13. A body panel according to claim 11, wherein the barrier coat exhibits an elongation at break of at least 2%.

14. A body panel according to claim 11, wherein the barrier coat comprises dicyclopentadiene resin and isophthalic resin in a ratio of 4:

1 and higher.

15. A body panel according to claim 11, wherein the laminate layer comprises a dicyclopentadiene resin and glass fibers of 6 mm in length or greater.

16. A body panel according to claim 15, wherein the laminate further comprises hollow polymeric microspheres.

17. A body panel according to claim 11, wherein the laminate layer, the barrier coat, or both further comprise a pigment.

18. A body panel according to claim 17, wherein the pigment comprises carbon black.

19. A body panel according to claim 11, wherein the barrier coat comprises reinforcing glass fibers of length 0.5 mm or less.

20. A barrier coat composition comprising:

a resin component comprising;

80-100 parts of dicyclopentadiene resin and up to 20 parts of an isophthalic acid resin, and

a reinforcing fiber component comprising fibers having a length of 1 mm or less.

21. A composition according to claim 20, wherein the reinforcing fiber component comprises fibers having a length of 0.5 mm or less.

22. A composition according to claim 20, wherein the fibers have a length of about 0.4 mm.

23. A composition according to claim 20, wherein the fibers have a length of about 0.025 mm.

24. A composition according to claim 20, wherein the composition exhibits an elongation at break of 1% or greater.

25. A composition according to claim 20, wherein the composition exhibits an elongation at break of 2% or greater.

26. A composition according to claim 20, wherein the barrier coat further comprises a filler selected from the group consisting of hollow glass microspheres and polymeric hollow microspheres.

27. A composition according to claim 20, wherein the resin comprises up to 40% by weight styrene monomer.

30. A method for preparing a composite article by spray up operation, comprising the steps of:

applying a gel coat into a mold;

applying a barrier coat over the gel coat in the mold; and

applying a laminate formula over the barrier coat, wherein the laminate formula contains 20-60% by weight of first reinforcing fibers having a first length of 6 mm or greater and 40-80% by weight of a paste comprising a laminate coat polyester resin;

wherein the barrier coat comprises second fibers having a length less than the first length dispersed in a barrier coat polyester resin.

31. A method according to claim 30, wherein the gel coat applied to a thickness of 0.2 to 2 mm, the barrier coat is applied to a thickness of 0.5 to 5 mm, and the laminate layer is applied to a thickness of 1-10 mm.

32. A method according to claim 30, wherein the thickness of the composite article is from 2 to 15 mm.

33. A method according to claim 30, wherein the composite article is an automotive body panel.

34. A method according to claim 30, wherein the laminate formula fiber comprises polymeric hollow microspheres.

35. A method according to claim 30, wherein the first reinforcing fiber comprise glass fibers of 12 mm or greater in length or a second fibers comprise glass fibers of 1 mm or less in length.

36. A method according to claim 30, wherein the barrier coat polyester resin comprises 75-100 parts of a dicyclopentadiene resin and 1-25 parts of an isophthalic acid resin.

37. A method of producing an automotive body panel comprising the steps of:

applying a gel coat composition to mold surface;

applying a barrier coat composition to the gel coat in the mold;

applying a fiber reinforced laminate composition comprising fibers having a first length onto the barrier coat and the mold;

curing at 50°

C. or less; and

removing the cured article from the mold,

wherein the barrier coat comprises polyester resin and glass fibers having a second length shorter than the first length.

38. A method according to claim 37, wherein the gel coat comprises a thermosetting resin.

39. A method according to claim 37, wherein the barrier coat exhibits elongation at break of 1% or greater.

40. A method according to claim 37, wherein the barrier coat exhibits elongation at break of 2% or greater.

41. A method according to claim 37, wherein the barrier coat comprises 100 parts of a polyester, including up to 20 parts of an isophthalic acid polyester resin.

42. A method according to claim 41, wherein the barrier coat comprises a dicyclopentadiene resin.

43. A method according to claim 42, wherein the barrier coat comprises glass fibers having a length of 1 mm or less.

44. A method according to claim 37, wherein the barrier coat comprises glass fibers having a length of 0.5 mm or less.

45. A method according to claim 37, comprising the steps of applying the gel coat to a thickness of 0.5-2 mm, applying the barrier coat to a thickness of 1-3 mm, and applying the laminate coat to a thickness of 2-5 mm.