Abstract: The present invention features phosphorus containing epoxy resin compositions useful for imparting flame retardant properties to prepregs, resin-clad metal foils, and laminate boards constructed therefrom. The phosphorus containing epoxy resin composition (a) comprises a phosphorus containing epoxy resin (A) and a hardener. The phosphorus containing epoxy resin (A) has an epoxy equivalent of 300-500 g/eq. and comprises the reaction product of a phosphorus containing organic compound (B) and at least one epoxy resin (C). Phosphorus containing compound (B) is the reaction product of organic phosphorus compounds (b) having one active hydrogen atom bonded to a phosphorus atom and a quinone compound, wherein the molar ratio of (b) to quinone is from 1.25:1 to 2:1. This molar excess of (b) yields a phosphorus containing compound (B) that comprises both the reaction product of (b) and quinone, as well as un-reacted (b).

Abstract: The present invention is to provide a phosphorus containing epoxy resin compositions, comprising an epoxy resin composition (a) in which a phosphorus containing epoxy resin (A) and a hardener are contained, wherein said phosphorus containing epoxy resin (A) is a phosphorus containing resin composition prepared by reacting phosphorus containing organic compounds (B) obtained by the reaction in the range of molar ratio of 1.01 to 2 moles of organic phosphorus compounds (b) having one active hydrogen atom bonded to phosphorus atom and 1 mole of quinone compound with at least one kind of epoxy resins (C) selected from the groups composed of general formula 1, general formula 2 or general formula 3 so as the content of said epoxy resins (C) to be from 20 to 45 wt.

Abstract: The present invention is to provide a phosphorus containing epoxy resin compositions, comprising an epoxy resin composition (a) in which a phosphorus containing epoxy resin (A) and a hardener are contained, wherein said phosphorus containing epoxy resin (A) is a phosphorus containing resin composition prepared by reacting phosphorus containing organic compounds (B) obtained by the reaction in the range of molar ratio of 1.01 to 2 moles of organic phosphorus compounds (b) having one active hydrogen atom bonded to phosphorus atom and 1 mole of quinone compound with at least one kind of epoxy resins (C) selected from the groups composed of general formula 1, general formula 2 or general formula 3 so as the content of said epoxy resins (C) to be from 20 to 45 wt.