Disclosed is a polymer material of low relative permittivity obtained
through copolymerization of a monomer composition that contains, as
monomers, a fumaric diester and an epoxy group-having (meth)acrylate. The
polymer material bonds or adheres well to metal conductor layers, and,
after crosslinked, it is patternable. In addition, it has good electric
properties of low relative permittivity, low dielectric loss tangent and
good electric insulation, and has good heat resistance.
