Patent ID: 7862749

Claim:
A free-flowing, non-viscous liquid flame retardant additive composition for blending with other ingredients to obtain a composition useful for producing flame retarded rigid polyurethanes, said additive composition consisting essentially of or formed by mixing together components consisting essentially of: A) at least one organic halogen-containing reactive flame retardant in which the halogen is bromine, chlorine or both; and B) at least one liquid aliphatic polyepoxide of the formula: R(Ep) n ; wherein R is a straight chain or branched chain aliphatic moiety which consists of carbon, hydrogen, and optionally, one or more ether oxygen atoms and/or one or more epoxy oxygen atoms; Ep is a terminal epoxy group: and n is a whole or fractional number in the range 2 to about 6; and optionally C) at least one organic phosphorus-containing flame retardant selected from the group consisting of C1) at least one organic phosphate ester and C2) at least one organic phosphonate ester: said additive composition having: (i) when C) is not present, an A):B) weight ratio in the range of about 97.7:2.3 to about 67:33; (ii) when C) is present other than a combination of C1) and C2), an A):B):C) weight ratio in the range of about 85:2:13 to about 30:15:55; and (iii) when C) is present as a combination of C1) and C2), an A):B):C1):C2) weight ratio in the range of about 85:2:12:1 to about 30:15:45:10.