Patent ID: 6277495
Filing Date: 2001-08-21
Classification: B32B,C08G,C08J,G02B,H05K,Y10T

Abstract:
A polyimide film having a birefringence less than 0.01, said polyimide film being made from a polyimide copolymer comprising:a block component and a random component which are molecularly bonded;said block component comprising a segment derived from an aromatic diamine compound of a rigid structure and an aromatic tetracarboxylic acid compound;said random component comprising a segment derived from an aromatic diamine compound of a flexible structure and at least two types of aromatic tetracarboxylic acid compounds;said aromatic diamine compound of a rigid structure being present in an amount from 12 mol % to 30 mol % of the total aromatic diamines used to make said polyimide copolymer; andsaid aromatic diamine compound of a flexible structure being present in an amount from 70 mol % to 88 mol % of the total aromatic diamines used to make said polyimide copolymer.