Claims
- 1. A process for making a prepreg which comprises the steps of:
- A. contacting a cloth mesh web or other fibrous reinforcing material with an intimately mixed with a composition which contains
- 1) a polyepoxide;
- 2) up to about 30 phr of a curing agent;
- 3) about 0.01 to 5.0 phr of boric acid;
- 4) 0.1 to 5.0 phr of a compound which catalyzes the reaction of the
- curing agent with the polyepoxide; and
- 5) at least one solvent; under conditions such that the reinforcing material is coated with the composition;
- heating the coated reinforcing material to evaporate the solvent and/or partially cure the composition, whereby a prepreg is formed.
- 2. The process of claim 1 wherein the catalyst contains a heterocyclic nitrogen compound or an ammonium, phosphonium or sulfonium compound.
- 3. The process of claim 2 wherein the catalyst contains a heterocyclic nitrogen compound.
- 4. The process of claim 3 wherein the composition contains about 0.1 to 2 phr catalyst.
- 5. The process of claim 1 wherein the composition contains no more than about 10 phr curing agent.
- 6. The process of claim 5 wherein the curing agent contains a polybasic acid or its anhydride, an amine-containing compound, a polyamide, or a melamine reaction product.
- 7. The process of claims 5 wherein the composition contains about 0.5 to about 4 phr curing agent.
- 8. The process of claim 7 wherein the curing agent contains dicyandiamide.
- 9. The process of claim 1 wherein the polyepoxide is an advanced epoxy resin.
- 10. The process of claim 1 wherein the concentration of boric acid is about 0.1 to about 2.0 phr.
- 11. The process of claim 1 wherein:
- (a) the curing agent contains a polybasic acid or its anhydride, an amine-containing compound, a polyamide, or a melamine reaction product, having a concentration of about 0.5 to 4 phr in the composition;
- (b) the catalyst is a heterocyclic nitrogen compound having a concentration of about 0.1 to 2 phr in the composition; and
- (c) the concentration of boric acid is about 0.1 to about 2.0 phr in the composition.
- 12. The process of claim 1 which further comprises the step of:
- C. heating a stack which contains layers of prepreg at elevated temperature and pressure for a time sufficient to cure the composition, whereby a laminate is formed.
- 13. The process of claim 12 wherein the catalyst contains a heterocyclic nitrogen compound or an ammonium, phosphonium or sulfonium compound.
- 14. The process of claim 13 wherein the catalyst contains a heterocyclic nitrogen compound.
- 15. The process of claim 14 wherein the composition contains about 0.1 to 2 phr catalyst.
- 16. The process of claim 12 wherein the curing agent contains a polybasic acid or its anhydride, an amine-containing compound, a polyamide, or a melamine reaction product.
- 17. The process of claim 16 wherein the composition contains about 0.5 to about 4 phr curing agent.
- 18. The process of claim 12 wherein the polyepoxide is an advanced epoxy resin.
- 19. The process of claim 12 wherein the concentration of boric acid is about 0.1 to about 2.0 phr.
- 20. The process of claim 12 wherein:
- (a) the curing agent contains a polybasic acid or its anhydride, an amine-containing compound, a polyamide, or a melamine reaction product, having a concentration of about 0.5 to 4 phr in the composition;
- (b) the catalyst is a heterocyclic nitrogen compound having a concentration of about 0.1 to 2 phr in the composition; and
- (c) the concentration of boric acid is about 0.1 to about 2.0 phr in the composition.
- 21. A prepreg which contains:
- (a) a reinforcing material which contains a cloth, a mesh, a web or fibers; and
- (b) a B-staged composition adhered to the reinforcing material, which contains:
- (1) a polyepoxide;
- (2) up to about 30 phr of a curing agent for the polyepoxide;
- (3) about 0.1 to 5.0 phr of boric acid; and
- (4) about 0.1 to 5.0 phr of a catalyst for the reaction of the polyepoxide and the curing agent.
- 22. The prepreg of claim 21 wherein the catalyst contains a heterocyclic nitrogen compound or an ammonium, phosphonium or sulfonium compound.
- 23. The prepreg of claim 22 wherein the catalyst contains a heterocyclic nitrogen compound.
- 24. The prepreg of claim 23 wherein the composition contains about 0.1 to 2 phr catalyst.
- 25. The prepreg of claim 21 wherein the composition contains no more than about 10 phr curing agent.
- 26. The prepreg of claim 25 wherein the curing agent contains a polybasic acid or its anyhydride, an amine-containing compound, a polyamide, or a melamine reaction product.
- 27. The prepreg of claim 25 wherein the composition contains about 0.5 to about 4 pr curing agent.
- 28. The prepreg of claim 27 wherein the curing agent contains dicyandiamide.
- 29. The prepreg of claim 21 wherein the polyepoxide is an advanced epoxy resin.
- 30. The prepreg of claim 21 wherein the concentration of boric acid is about 0.1 to about 2.0 phr.
CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation of application Ser. No. 08/171,938, filed Dec. 22, 1993, now abandoned, which is a division of application Ser. No. 07/848,499 filed Mar. 6, 1992 U.S. Pat. No. 5,308,895 which is a continuation -in-part of application Ser. No. 07/526,487 filed May 21, 1990 (now abandoned), all of which are incorporated herein by reference in their entirety.
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Entry |
H. Lee & K. Neville, Handbook of Epoxy Resins, (1967), p. 11-4. |
H. Lee & K. Neville, "Handbook of Epoxy Resins", 1967, pp. 11-1, 11-2, 11-11, 11-12, 11-18, 10-17. |
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Divisions (1)
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Number |
Date |
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Parent |
848499 |
Mar 1992 |
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Continuations (1)
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Date |
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171938 |
Dec 1993 |
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Continuation in Parts (1)
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Number |
Date |
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526487 |
May 1990 |
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