phosphates with formula 1, wherein R1, R2, R3 and R4 represent a phenyl-group, m1, m2, m3 and m4 are all 1, X is a phenylene group and n has an average value of about 1.4.Phosphate-2 a mixture of several oligomeric phosphates with the same structure as phosphate-1, but with an average value of n of approximately 2.8.TPP-1 triphenyl phosphateTPP-2 a 40/60