Abstract: The invention provides a composition comprising a resin processable at temperatures upto 160.degree. C. having incorporated therein a flame retardant amount of a salt formed by reaction between dimethyl methyl phosphonate, monomethyl methyl phosphonate or methyl phosphonic acid, and a compound of the general formula (I) ##STR1## in which X is 0 or S; R.sup.1 is H, alkyl with 1 to 4 carbon atoms, alkenyl of up to 4 carbon atoms, CN, CONH.sub.2 or NH.sub.2, R.sup.2 is H, alkyl with 1 to 4 carbon atoms or alkenyl of up to 4 carbon atoms or R.sup.1 and R.sup.2 together with the nitrogen atom to which they are attached form a heterocyclic ring of up to 6 carbon atoms which may optionally contain another hetero atom and R is H, an alkyl group with 1 to 8 carbon atoms, an aryl group with 6 to 10 carbon atoms, a cycloalkyl group with 5 to 12 carbon atoms or a heterocyclic group with up to 9 ring carbon atoms, or, together with R.sup.1 forms an alkylene chain of 3 to 10 carbon atoms, or R is a group NHR.sup.

Abstract: The invention provides polyurethanes and polyisocyanurate having incorporated therein a flame retardant amount of a salt formed by reaction between dimethyl methyl phosphonate, monomethyl methyl phosphonate or methyl phosphonic acid, and a compound of the general formula (I). ##STR1## in which X is O, S or NH, R.sup.1 is H, alkyl with 1 to 4 carbon atoms, alkenyl of up to 4 carbon atoms, CN, CONH.sub.2 or NH.sub.2, R.sup.2 is H, alkyl with 1 to 4 carbon atoms or alkenyl of up to 4 carbon atoms or R.sup.1 and R.sup.2 together with the nitrogen atom to which they are attached form a heterocyclic ring of up to 6 carbon atoms which may optionally contain another hetero atom and R is H, an alkyl group with 1 to 8 carbon atoms, an aryl group with 6 to 10 carbon atoms, a cycloalkyl group with 5 to 12 carbon atoms or a heterocyclic group with up to 9 ring carbon atoms, or, together with R.sup.1 forms an alkylene chain of 3 to 10 carbon atoms, or R is a group NHR.sup.3 wherein R.sup.