Patent ID: 9585248
Date: 2017-02-28
CPC Classifications: B32B,C08G,C08J,C08L,C09D,H05K,Y10T

Claim:
1. A prepreg consisting of a fibrous base material and a resin composition varnish wherein the resin composition comprises at least one curable resin selected from the group consisting of epoxy resin, phenolic resin, imide resin, cyanate ester resin, vinyl ester resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, unsaturated polyester resin, and melamine-urea co-condensed resin; a curing agent, a second resin having an inorganic filler, and a solvent; wherein the resin composition becomes a cured product that exhibits force response behavior such that an area surrounded by a tensile stress-strain curve f1(x), when an amount of strain is increased from 0% to 0.3% by pulling at 999 μm/min while plotting the amount of strain on the x axis and tensile stress on the y axis, and also surrounded by the x axis, is greater than an area surrounded by a stress-strain curve f2(x), when the amount of strain is decreased from 0.3%, and also surrounded by the x axis, and the amount of change in the amount of strain when tensile stress is 0, before and after applying tensile stress, is 0.05% or less.