POLYAMIC ACID SOLUTION, POLYIMIDE FILM, AND METHOD FOR CONTROLLING PROPERTIES OF POLYIMIDE FILM

摘要

PROBLEM TO BE SOLVED: To obtain a polyamic acid soln. which is useful for producing a polyimide film of which the refractive index or thermal expansion coefficient can be controlled without detriment to the light transmittance and which exhibits a remarkably decreased birefringence by using a polyamic acid and fine silicon dioxide particles having specified particle sizes as the main ingredients and by adjusting the content of the particles. ;SOLUTION: Fine silicone dioxide particles having particle sizes of 0.5-50 nm, pref. 5-50 nm, and a polyamic acid, pref. a fluorinated polyamic acid [e.g. one prepd. by reacting 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride with 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl], are used as the main ingredients. The amt. of the silicone dioxide particles incorporated into a polyimide film is required to be 50 wt.% or lower in terms of mechanical strengths and to be 1 wt.% or higher in terms of controlling the properties.;COPYRIGHT: (C)1999,JPO