Patent ID: 7550194
Filing Date: 2009-06-23
Classification: B32B,C08G,C08L,C09K,Y10T

Abstract:
1. A film comprising polyimide, the polyimide comprising a repeat unit obtained by contacting a first dianhydride component and a first diamine component, the repeat unit being represented by the formula, wherein n represents the number of repeating units and n is an integer between 10 and 100,000, wherein the repeat unit is present at a mole percent between and including 95 and 50 mole percent, based upon the total moles of repeat units in the polyimide film, the film further comprising a fumed filler selected from a group consisting of dicalcium phosphate, silicon dioxide, alumina, and titanium dioxide, wherein the polyimide is also derived from a second diamine component, wherein the first diamine component and the second diamine component comprising a total diamine component, wherein the second diamine component is reacted into the polyimide in an amount between and including 5 and 50 mole percent, and of the total diamine component reacted into the polyimide, and wherein the second diamine component is selected from a group consisting of trans-1,4-diaminocyclohexane and diaminocyclooctane, wherein the polyimide is also derived from a second dianhydride component wherein the first dianhydride component and the second dianhydride component comprise a total dianhydride component, wherein the second dianhydride component is incorporated into the polyimide in an amount between and including 5 and 50 mole percent of the total dianhydride component, and wherein the second dianhydride component is selected from the group consisting of 1,2,3,4 -cyclobutanetetracarboxylic acid dianhydride; bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylicdianhydride; and 9,9-disubstituted xanthene dianhydrides, wherein the polyimide film has an in-plane coefficient of thermal expansion (CTE) between and including and 20 ppm/° C., wherein the polyimide has a glass transition temperature(Tg) of between and including 250° and 500° C., wherein the film has a thickness between and including and 200 microns, wherein the film has a average light transmittance percent between 65.0 and 99.0 when the film is exposed to light between the wavelengths of 380 to 770 nanometers, and wherein the film is made by a cast chemical conversion process, the process employing the use of a dehydrating agent and a catalyst to increase the rate of chemical reaction of the polyamic acid to polyimide, the process forming a gel film, said gel film being heated to further imidize the film.