A flame retardant polymer composition comprising: a) a thermoset or thermoplastic polymer; b) from 1% to 50%, by weight based on the total weight of the flame retardant polymer composition, of a flame retardant material obtained by a process comprising heating at temperatures of 200°C or higher from 0.01 hour to 20 hours one or more than one compound of formula wherein R is C 1-12 alkyl, C 6-10 aryl, C 7-18 alkylaryl, or C 7-18 arylalkyl, wherein said alkyl, aryl, alkylaryl, or arylalkyl are unsubstituted or are substituted by halogen, hydroxyl, amino, C 1-4 alkylamino, di-C 1-4 alkylamino, C 1-4 alkoxy, carboxy or C 2-5 alkoxycarbonyl; M is a metal, y is a number of from 1 to 4 so that M (+)y is a metal cation where (+)y represents the charge formally assigned to the cation, and p is a number of from 1 to 4, said flame retardant material comprising one or more compounds of formula: wherein R is C 1-12 alkyl, C 6-10 aryl, C 7-18 alkylaryl, or C 7-18 arylalkyl, wherein said alkyl, aryl, alkylaryl, or arylalkyl are unsubstituted or are substituted by halogen, hydroxyl, amino, C 1-4 alkylamino, di-C 1-4 alkylamino, C 1-4 alkoxy, carboxy or C 2-5 alkoxycarbonyl; M is a metal; q is a number of from 1 to 7; r is a number from 0 to 5; y is a number of from 1 to 7; and n is1 or 2, provided that 2(q) +r = n(y); and c) one or more compounds selected from the group consisting of hydrotalcite clays, calcium or zinc borate, calcium or zinc oxide and calcium or zinc hydroxide. a) a thermoset or thermoplastic polymer; b) from 1% to 50%, by weight based on the total weight of the flame retardant polymer composition, of a flame retardant material obtained by a process comprising heating at temperatures of 200°C or higher from 0.01 hour to 20 hours one or more than one compound of formula wherein R is C 1-12 alkyl, C 6-10 aryl, C 7-18 alkylaryl, or C 7-18 arylalkyl, wherein said alkyl, aryl, alkylaryl, or arylalkyl are unsubstituted or are substituted by halogen, hydroxyl, amino, C 1-4 alkylamino, di-C 1-4 alkylamino, C 1-4 alkoxy, carboxy or C 2-5 alkoxycarbonyl; M is a metal, y is a number of from 1 to 4 so that M (+)y is a metal cation where (+)y represents the charge formally assigned to the cation, and p is a number of from 1 to 4, said flame retardant material comprising one or more compounds of formula: wherein R is C 1-12 alkyl, C 6-10 aryl, C 7-18 alkylaryl, or C 7-18 arylalkyl, wherein said alkyl, aryl, alkylaryl, or arylalkyl are unsubstituted or are substituted by halogen, hydroxyl, amino, C 1-4 alkylamino, di-C 1-4 alkylamino, C 1-4 alkoxy, carboxy or C 2-5 alkoxycarbonyl; M is a metal; q is a number of from 1 to 7; r is a number from 0 to 5; y is a number of from 1 to 7; and n is1 or 2, provided that 2(q) +r = n(y); and R is C 1-12 alkyl, C 6-10 aryl, C 7-18 alkylaryl, or C 7-18 arylalkyl, wherein said alkyl, aryl, alkylaryl, or arylalkyl are unsubstituted or are substituted by halogen, hydroxyl, amino, C 1-4 alkylamino, di-C 1-4 alkylamino, C 1-4 alkoxy, carboxy or C 2-5 alkoxycarbonyl; M is a metal, y is a number of from 1 to 4 so that M (+)y is a metal cation where (+)y represents the charge formally assigned to the cation, and p is a number of from 1 to 4, said flame retardant material comprising one or more compounds of formula: wherein R is C 1-12 alkyl, C 6-10 aryl, C 7-18 alkylaryl, or C 7-18 arylalkyl, wherein said alkyl, aryl, alkylaryl, or arylalkyl are unsubstituted or are substituted by halogen, hydroxyl, amino, C 1-4 alkylamino, di-C 1-4 alkylamino, C 1-4 alkoxy, carboxy or C 2-5 alkoxycarbonyl; M is a metal; q is a number of from 1 to 7; r is a number from 0 to 5; y is a number of from 1 to 7; and n is1 or 2, provided that 2(q) +r = n(y); and R is C 1-12 alkyl, C 6-10 aryl, C 7-18 alkylaryl, or C 7-18 arylalkyl, wherein said alkyl, aryl, alkylaryl, or arylalkyl are unsubstituted or are substituted by halogen, hydroxyl, amino, C 1-4 alkylamino, di-C 1-4 alkylamino, C 1-4 alkoxy, carboxy or C 2-5 alkoxycarbonyl; M is a metal; q is a number of from 1 to 7; r is a number from 0 to 5; y is a number of from 1 to 7; and n is1 or 2, provided that 2(q) +r = n(y); and c) one or more compounds selected from the group consisting of hydrotalcite clays, calcium or zinc borate, calcium or zinc oxide and calcium or zinc hydroxide.