Composite film comprising low-dielectric resin and paraoriented aromatic polyamide

摘要

Provided is a composite film comprising a continuous phase of para-oriented aromatic polyamide and a phase of low-dielectric resin, said film having a dielectric constant at 1 MHz of not more than 3.2 and a linear thermal expansion coefficient at 200 to 300 DEG C. of within +/-50x10-6/ DEG C. The composite film has characteristics such as a low dielectric constant, favorable mechanical strength, homogeneous structure, light weight, and a low linear thermal expansion coefficient, and the film is useful as a base substrate for a flexible printed circuit board.