Patent ID: 8062750
Filing Date: 2011-11-22
Classification: C08G,H05K,Y10T

Abstract:
1. An epoxy resin composition for a prepreg used in manufacturing a printed wiring board, said composition comprising: (A) a multifunctional epoxy resin having on average 2.8 or more epoxy groups per molecule; (B) a reaction product of a phosphorous compound, a bifunctional epoxy resin, and an optional multifunctional epoxy resin, wherein the phosphorous compound has on average 1.8 to 3 phenolic hydroxyl groups per molecule and on average 0.8 or more phosphorous atoms per molecule, the bifunctional epoxy resin has on average 1.8 to 2.6 epoxy groups per molecule, and the optional multifunctional epoxy resin has on average 2.8 or more epoxy groups per molecule; (C) a curing agent selected from dicyandiamide, a multifunctional phenolic compound or a combination thereof; and (D) an inorganic filler blend comprising a first inorganic filler having a thermal decomposition temperature (weight loss by 5%) at 400° C. or above and at least one additional inorganic filler different from said first inorganic filler; wherein the reaction product (B) is formulated and reacted with a ratio of epoxy equivalent of the bifunctional epoxy to hydroxy equivalent of the phosphorous compound ranging from 1.2 to less than 3, and a ratio of epoxy equivalent of the optional multifunctional epoxy resin to hydroxy equivalent of the phosphorous compound ranging from 0.05 to less than 0.8; wherein the reaction product (B) is provided in an amount of 20% to 55% by mass based on the total amount of epoxy resin, including (A) and (B), present in the epoxy resin composition; wherein the bifunctional epoxy resin is selected from epoxy resins represented by formula (1), formula (2), formula (3) or formula (4); wherein the inorganic filler blend (D) is provided in an amount of 110 to less than 200 parts by mass per 100 parts by mass of resin solids; and wherein the first inorganic filler is provided in an amount of 20 to less than 180 parts by mass per 100 parts by mass of resin solids.