Patent ID: 9578734
Date: 2017-02-21
CPC Classifications: B32B,C08G,C08J,C08L,H05K,Y10T

Claim:
1. A prepreg formed by drying a fabric substrate impregnated with a resin composition by means of heating until the resin composition is in a semi-cured state, the resin composition comprising: (A) an epoxy resin and a phenolic curing agent; and (B) a polymer having structures represented by the following formulae (I) and (II), no unsaturated bond between carbon atoms, an epoxy value falling within a range of 0.2 to 0.7 ep/kg, and a weight-average molecular weight falling within a range of 260,000 to 850,000: and, wherein: X:Y=0:1 to 0.35:0.65, R the fabric substrate is a fabric in which a warp thread and a weft thread are woven so as to be almost perpendicular to each other, at least one of the epoxy resin and the phenolic curing agent has a naphthalene skeleton, and a ratio of a loss elastic modulus to a storage elastic modulus in each of temperature ranges of not greater than 60° C. and not less than 231° C. of the prepreg is 0.05 or more when the resin composition is in a fully-cured state.