SHEET MATERIAL AND WIRING BOARD

摘要

A sheet material (1) which comprises an adhesive layer (2) and a high-strength layer (3) superposed on this adhesive layer (2). The adhesive layer (2) is made of an epoxy resin which is a thermosetting material. The high-strength layer (3) is made of a polyimide which does not soften at a temperature to be used for thermally curing the epoxy resin, has a tensile strength at break higher than that of the thermosetting material after cure, has a tensile strength at break as measured at 23°C of 100 MPa or higher and an elongation at break as measured at 23°C of 10% or higher and has an a/b ratio of 2.5 or lower, wherein a is the tensile strength at break as measured at -65°C and b is the tensile strength at break as measured at 150°C.