Flame retardant phosphonate additives for thermoplastics
The invention is directed to a phosphonate composition having flame retardant properties. The phosphonate composition of the invention has the general formula: wherein R 1 and R 2 are independently C 1 –C 4 alkyl, R 3 is H or C 1 –C 4 alkyl, and R 4 is linear or branched C9–C22 alkyl, C9–C22 cycloalkyl, C9–C22 aryl or C9–C22 aralkyl and n=0 or 1. The invention is also directed to a method of producing the phosphonate composition having flame retardant properties.
1. A phosphonate composition having the general formula:
wherein
R 1 and R 2 are independently C 1 –C 4 alkyl,
R 3 is H or C 1 –C 4 alkyl, and
R 4 is linear or branched C9–C22 alkyl, C9–C22 cycloalkyl, C9–C22 aryl or C9–C22 aralkyl and
n=0 or 1.
2. The composition of claim 1 wherein R1 and R2 are methyl groups, R 3 is ethyl, R 4 is substituted or un-substituted C10–C18 alkyl.
3. The composition of claim 2 wherein R 4 is C10 or C12 alkyl.
4. The composition of claim 1 wherein R 1 and R 2 are methyl groups, R 3 is ethyl, R 4 is substituted or un-substituted C10–C12 cycloalkyl.
5. The composition of claim 4 wherein R 4 is 4-t-butylcyclohexyl.
6. The composition of claim 4 wherein R 4 is camphyl.
7. A flame retarded thermoplastic resin composition comprising a phosphonate having flame retardant properties, said phosphonate having the general formula
wherein
R 1 and R 2 are independently C 1 –C 4 alkyl,
R 3 is H or C 1 –C 4 alkyl, and
R 4 is linear or branched C9–C22 alkyl, C9–C22 cycloalkyl, C9–C22 aryl or C9–C22 aralkyl and
n=0or 1.
8. The composition of claim 7 wherein R 1 and R 2 are methyl groups, R 3 is ethyl, R 4 is substituted or un-substituted C10–C18 alkyl.
9. The composition of claim 8 wherein R 4 is C10 or C12 alkyl.
10. The composition of claim 7 wherein R 1 and R 2 are methyl groups, R 3 is ethyl, R 4 is substituted or un-substituted C10–C12 cycloalkyl.
11. The composition of claim 10 wherein R 4 is 4-t-butylcyclohexyl.
12. The composition of claim 10 wherein R 4 is camphyl.
13. A method of producing a flame retardant phosphonate composition of the general formula (IV):
wherein
R 1 and R 2 are independently C 1 –C 4 alkyl,
R 3 is H or C 1 –C 4 alkyl, and
R 4 is linear or branched C9–C22 alkyl, C9–C22 cycloalkyl, C9–C22 aryl or C9–C22 aralkyl and
n=0 or 1:
wherein said method comprises the steps of:
1) first reacting trimethylolalkane of general formula (I), wherein R 3 is H or C1–C4 alkyl with a phosphite of the general formula P(OR) 3 , wherein R is alkyl, aryl or aralkyl, in a molar ratio sufficient to produce a cyclic phosphite of general formula (II)
2) second reacting said cyclic phosphite of the general formula (II) with a phosphonate of general formula (III),
wherein R 1 and R 2 are independently C 1 –C 4 alkyl and R 4 is linear or branched C9–C22 alkyl, C9–C22 cycloalkyl, C9–C22 aryl or C9–C22 aralkyl, in a molar ratio sufficient to produce said flame retardant phosphonate composition of said general formula (IV).
14. The method of claim 13 wherein said step of reacting trimethylolalkane of general formula (I) with said phosphite the general formula P(OR) 3 is performed at temperatures of from about 50° C. to about 200° C. in the presence or absence of a transesterification catalyst.
15. The method of claim 14 wherein the said step is performed at temperatures of from about 80° C. to about 160° C.
16. The method of claim 14 wherein the said step is performed in the presence of a transesterification catalyst.
17. The method of claim 16 wherein the acid catalyst is methyl acid phosphate.
18. The method of claim 13 wherein said trimethylolalkane comprises trimethylolpropane.
19. The method of claim 13 wherein said phosphite of the general formula P(OR) 3 comprises trimethyl phosphite.
20. The method of claim 13 wherein said phosphite of the general formula P(OR) 3 comprises triphenyl phosphite.
21. The method of claim 13 wherein said step of reacting said cyclic phosphite of the general formula (II) with a phosphonate of general formula (III) is performed at temperatures of about 150° C. to about 250° C. in the presence or absence of a alkyl halide catalyst and or a color inhibitor.
22. The method of claim 21 wherein the said step is performed in the presence of an alkyl halide catalyst.
23. The method of claim 22 wherein the alkyl halide catalyst is butyl bromide.
24. The method of claim 22 wherein the alkyl halide catalyst is octyl bromide.
25. The method of claim 22 wherein the alkyl halide catalyst is methyl iodide.
26. The method of claim 21 wherein the said step is performed in the presence of a color inhibitor.
27. The method of claim 26 wherein the color inhibitor is N-methylethanol amine.
28. The method of claim 21 wherein the said step is performed at temperatures of about 180° C. to about 220° C.
29. The method of claim 21 wherein said phosphonate of general formula (III) is dimethyl decylphosphonate.
30. The method of claim 21 wherein said phosphonate of general formula (III) is dimethyl laurylphosphonate.
31. The method of claim 21 wherein said phosphonate of general formula (III) is dimethyl (4-t-butylcyclohexyl) phosphonate.
32. The method of claim 21 wherein said phosphonate of general formula (III) is dimethyl camphylphosphonate.