Patent ID: 6933050

Claim:
A phosphorus containing epoxy resin composition (a) comprising a phosphorus containing epoxy resin (A) and a hardener, said phosphorus containing epoxy resin (A) comprising the reaction product of a phosphorus containing organic compound (B) and at least an epoxy resin (C); wherein the epoxy equivalent of phosphorous containing epoxy resin (A) is 300-500 g/eq wherein (B) is the reaction product of organic phosphorus compounds (b) having one active hydrogen atom bonded to a phosphorus atom and a quinone compound, said reaction product containing an unreacted component, said reaction product formed with a molar ratio of (b) to quinone of 1.25:1 to 2:1 and containing an excess of organic phosphorous compounds (b) as said unreacted component, wherein (C) is selected from the group, consisting of resins represented by formula 1, formula 2 and formula 3 wherein the content of said epoxy resins (C) comprises from 20 to 45 wt. % of (A), wherein R 1 is a hydrogen atom and/or a phenyl group, m is an integer including 0, wherein R 2 is a hydrogen atom and/or a phenyl group, n is an integer including 0, wherein R 3 is a hydrogen atom and/or a phenyl group, l is an integer including 0, wherein X is selected from the group consisting of —CH 2 —, —O—, —CO—, —SO 2 —, —S—, —CH(C 6 H 5 )—, —C(C 6 H 5 ) 2 —, a bond and a structure represented by formula 4