Claims
- 1. A process for preparing a phenolic cyanate resin of the formula: ##STR8## which process comprises reacting a base with a phenolic resin of the formula: ##STR9## to form the corresponding base salt of said phenolic, and reacting said base salt with cyanogen halide in an aprotic solvent at a temperature less than about 0.degree. C. to form said phenolic cyanate resin, wherein:
- q and r are the same or different and are whole numbers from 0 to 3, with the proviso that the sum of q and r at each occurrence is equal to 3;
- Z is --OH and --OCN or --OCN;
- o and p are the same or different at each occurrence and are positive whole numbers from 0 to 4, with the proviso that the sum of o and p at each occurrence is equal to 4; X is a divalent organic radical,
- R.sub.3 is the same or different at each occurrence and is a substitutent other than hydrogen which is unreactive under conditions necessary to cross link the cyanate moieties; and
- n is a positive whole number equal to or greater than 1; wherein said phenolic cyanate forms no or substantially no solids which are insoluble in tetrahydrofuran on storage at room temperature (about 20.degree. C.) for a period of more than 3 days.
- 2. The process of claim 1 wherein said temperature is less than about -5.degree. C.
- 3. The process of claim 2 wherein said temperature is less than about -10.degree. C.
- 4. The process of claim 3 wherein said temperature is less than about -15.degree. C.
- 5. The process of claim 1 wherein the mole % of carbamate functions is equal to or less than about 10 mole % based on the total moles of phenyl groups in said cyanate.
- 6. The process of claim 5 wherein said mole % is less than about 2 mole %.
- 7. The process of claim 6 wherein said mole % is less than about 1 mole %.
- 8. The process of claim 2 wherein said base is selected from the group consisting of tertiary amines, alkali metal hydroxides and alkali metal carbonates.
- 9. The process of claim 8 wherein said base is selected from the group consisting of tertiary amines.
- 10. The process of claim 9 wherein said tertiary amines are trialkyl amines.
- 11. The process of claim 10 wherein the weight % of dicyanamide is equal to or less than about 10 weight percent based on the total weight of the phenolic cyanate.
- 12. The process of claim 11 wherein the weight % of dicyanamide is less than about 5 weight %.
- 13. The process of claim 12 wherein the weight % of dicyanamide is less than about 2 weight %.
- 14. The process of claim 13 wherein the weight % of dicyanamide is less than about 1 weight %.
- 15. The process of claim 14 in which the resin is substantially free of dicyanamide.
- 16. The process of claim 1 wherein said period is from more than 3 days to 90 days.
- 17. The process of claim 16 wherein said period is about 90 days.
- 18. The process of claim 1 wherein said period is more than about 90 days.
- 19. The process of claim 1 wherein the completely cured phenolic triazine of said phenolic cyanate exhibits a weight loss equal to or less than about 16 wgt % based on the total weight of the phenolic triazine on heating said phenolic triazine from about 20.degree. C. to about 500.degree. C. at a rate of 10.degree. C./min in an argon atmosphere.
- 20. The process of claim 19 wherein said weight loss is equal to or greater than about 14 wgt. %.
- 21. The process of claim 20 wherein said weight loss is equal to or less than about 13 wgt. %.
- 22. A process of claim 1 wherein a completely cured product of said phenolic cyanate exhibits a weight loss equal to or less than about 6 wgt. based on the total weight of the completely cured product on heating said product from about 20.degree. C. to a temperature of about 450.degree. C. at a rate of 10.degree. C./min in an argon atmosphere.
- 23. A process of claim 21 wherein said weight loss is equal to or less than about 2.5 wgt %.
- 24. The process of claim 1 wherein a completely cured product of the phenolic cyanate exhibits no weight loss on heating said product from about 20.degree. C. to 400.degree. C. at a rate of 10.degree. C./min in an argon atmosphere.
- 25. The process of claim 1 wherein said phenolic cyanate resin forms no or substantially no solids which are insoluble in tetrahydrofuran on storage of said resin for a period of from more than 3 days to about 90 days at room temperature (about 20.degree. C.), and wherein the completely cured product of said resin exhibits a weight loss equal to or less than about 16 wgt. % based on the total weight of the completely cured product on heating said product from about 20.degree. C. to about 500.degree. C. at a rate of 10.degree. C./min in an argon atmosphere.
- 26. The process of claim 1 wherein --X-- is substituted or unsubstituted methylene or 1,4-phenyldimethylene, wherein permissible substituents are alkyl having 1 to about 10 carbon atoms, halogen or furyl.
- 27. A process of claim 26 wherein --X-- is methylene, alkyl substituted methylene or 1,4-phenyldimethylene.
- 28. A process of claim 1 wherein n is from 1 to about 20.
- 29. A process of claim 27 wherein n is from about 1 to about 10.
- 30. A process of claim 29 wherein n is from about 3 to about 10.
- 31. A process of claim 29 wherein:
- o is 0 or 1;
- p is 2 or 4;
- q is 0 or 1; and
- r is 2 or 3.
- 32. A process of claim 31 wherein:
- o is 0; and
- p is 4;
- q is 0; and
- r is 3.
- 33. A process of claim 31 wherein R.sub.3 is alkyl.
- 34. A process of claim 33 wherein R3 is methyl.
- 35. A process of claim 34 wherein Z is substantially 100% --OCN.
- 36. A process of claim 10 wherein:
- Z is substantially 100% --OCN;
- o and q are 0;
- p is 4; and
- r is 3.
- 37. A process of claim 36 wherein said phenolic cyanate resin forms no or substantially no solids which are insoluble in tetrahydrofuran on storage of said resin for a period of from more than 3 days to about 90 days, and wherein the completely cured product of said resin exhibits a weight loss equal to or less than about 16 wgt % based on the total weight of the completely cured product on heating said product from about 20.degree. C. to about 500.degree. C. at a of 10.degree. C./min in an argon atmosphere.
- 38. A process of claim 37 wherein --X-- is methylene, alkyl substituted methylene or 1,4-phenyl dimethylene.
- 39. A process of claim 38 wherein n is from 1 to about 10.
- 40. A process of claim 39 wherein --X-- is methylene.
- 41. A process of claim 40 wherein said base is a trialkylamine, and said cyanate resin contains less than about 1% by wgt of dialkylcyanamide based on the total weight of the resin.
- 42. The process of claim 41 wherein said cyanate resin contains less than about 1% by wgt of the cyanated phenol precursor of said phenolic cyanate.
- 43. The process of claim 35 wherein said temperature is equal to or less than about -5.degree. C.
Parent Case Info
This application is a division of application Ser. No. 357,637, filed May 26, 1989, now U.S. Pat. No. 4,970,276 which, in turn, is a continuation of application Ser. No. 041,018, filed Mar. 3, 1987, now abandoned, based on PCT/US 8700123, filed Jan. 16, 1987, which, in turn, is a continuation-in-part of application Ser. No. 821,658, filed Jan. 23, 1986, now abandoned.
US Referenced Citations (18)
Foreign Referenced Citations (7)
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Divisions (1)
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Number |
Date |
Country |
Parent |
357637 |
May 1989 |
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Continuations (1)
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Number |
Date |
Country |
Parent |
41018 |
Mar 1987 |
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Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
821658 |
Jan 1986 |
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