Claims
- 1. A cyanato group containing phenolic resin of the formula ##STR5## wherein n is o or an integer of 1 or more, R is the same or different and is selected from hydrogen and methyl groups, the resin having a residual amount of phenyl cyanate of less than 2% by weight and said resin having a gel time of greater than 1 minute at 155.degree. C.
- 2. A method to make a cyanato group containing phenolic resin of the formula ##STR6## wherein n is 0 or an integer of 1 or more, R is the same or different and is selected from hydrogen and methyl groups, comprising the steps of:
- reacting novolac resin and a trialkyl amine to form the trialkylammonium salt of novolac, followed by
- reacting the trialkylammonium salt with cyanogen halide in a cyclic ether at a temperature below about 31 5.degree. C. to form the cyanato group containing phenolic resin.
- 3. A resin according to claim 1 having a residual amount of phenyl cyanate of less than about 0.5% by weight.
- 4. The resin of claim 1 wherein the gel time is greater than 2 minutes.
- 5. The resin of claim 4 wherein the gel time is greater than 10 minutes.
- 6. The resin of claim 1 having a residual amount of cyanamide of less than about 2 percent by weight.
- 7. The resin of claim 1 having a residual amount of cyanamide of less than about 0.5 percent by weight.
- 8. A phenolic triazine resin derived from the cyanato group containing phenolic resin recited in claim 1.
- 9. A cyanato group containing phenolic resin of the formula ##STR7## wherein n is 0 or an integer of 1 or more, R is the same or different and is selected from hydrogen and methyl groups, the resin being capable of forming phenolic triazine resin having a char yield of at least about 50% by weight at 900.degree. C. as measured by thermal gravimetric analysis.
- 10. The resin of claim 9 having a gel time of greater than about 1 minute at 155.degree. C.
- 11. The resin of claim 10 having a gel time of greater than about 10 minutes at 155.degree. C.
- 12. The resin of claim 11 wherein no volatiles or substantially no volatiles are released from the resin during gel time measurements.
- 13. The resin of claim 9 having a residual amount of phenyl cyanate of less than about 2% by weight and a residual amount of cyanamide of less than about 2% by weight.
- 14. The resin of claim 13 having a residual amount of phenyl cyanate of less than about 0.5% by weight and a residual and of cyanand of less than about 0.5% by weight.
- 15. A phenolic triazine resin derived from the cyanato group containing phenolic resin recited in claim 9.
- 16. A cyanato group containing phenolic resin of the formula ##STR8## wherein n is 0 or an integer of 1 or more, R is the same or different and is selected from hydrogen and methyl groups, the resin having a residual amount of cyanamide of less than 2 percent by weight.
- 17. The resin of claim 16 wherein the residual amount of cyanamide is about 0% by weight.
- 18. A phenolic triazine resin derived from the cyanato group containing phenolic resin recited in claim 9.
- 19. The resin of claim 16 having gel time of more than about 1 minute at 155.degree. C.
- 20. The resin of claim 19 having a gel time of greater than about 10 minutes at 155.degree. C.
- 21. The resin of claim 20 wherein no volatiles or substantially no volatiles are released from the resin during gel time measurements.
- 22. The resin of claim 16 having a residual amount of phenyl cyanate of less than about 2% by weight.
- 23. The resin of claim 22 having a residual anal of phenyl cyanate of less than about 0.5% by weight.
- 24. A resin of claim 1, 2 or 9, wherein R is the same at each occurrence and is hydrogen.
- 25. A method as recited in claim 2 wherein the amount of phenolic cyanate and dialkyl cyanamide is less than about 2% by weight.
- 26. The method as recited in claim 2 wherein the step of reacting the trialkylammonium salt with the cyanogen halide at below about 31 5.degree. C. to -45.degree. C.
- 27. The method as recited in claim 26 wherein the step of reacting the trialklammonium salt with the cyanogen halide at below about -5.degree. C. to -30.degree. C.
- 28. The method as recited in claim 27 wherein the step of reacting the trialkylammonium salt with cyanogen halide at below about -15.degree. C. to -30.degree. C.
- 29. The method as recited in claim 2 wherein the cyclic ether solvent is selected from the group consisting of tetrahydrofuran, 1,4 dioxan, and furan.
- 30. The method as recited in claim 2 wherein the cyanogen halide is cyanogen bromide.
- 31. The method as recited in claim 2 wherein the trialkylamine is triethyl amine.
Parent Case Info
This application is a division, of application Ser. No. 104,700, filed Oct. 5, 1987 now U.S. Pat. No. 4,831,086.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
4831086 |
Das et al. |
May 1989 |
|
Divisions (1)
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Number |
Date |
Country |
Parent |
104700 |
Oct 1987 |
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