Abstract: A transparent polyimide film, prepared from a copolymerized polyamide acid according to a chemical cyclization method, is provided. The copolymerized polyamide acid requires at least a semi-aromatic polyamide acid, and the semi-aromatic polyamide acid is formed by reacting cyclobutane-1,2,3,4-tetracarboxylic dianhydride (CBDA) and 2,2?-bis(trifluoromethyl)diaminodiphenyl (TFMB). The molar number of dianhydrides of the semi-aromatic polyamide acid is more than 20% of the total molar number of anhydrides of the copolymerized polyamide acid, so that the transparent polyimide film has a light transmittance greater than 80%, a chroma b* less than 5, and a CTE less than 35 ppm/° C.

Abstract: A transparent polyimide film manufacturing method includes following steps: producing a polyimide film having a tensile modulus of elasticity greater than 5.4 GPa ((N/m2)×109), a light transmittance greater than 85%, and a chromaticity b* less than 2; providing an ether-free dianhydride and a diamine to form an ether-free polyamic acid; reacting the ether-free polyamic acid with an aromatic cyclic dianhydride to form a copolymerized polyamic acid; and chemically cyclizing the copolymerized polyamic acid to form a transparent polyimide film.

Abstract: The instant disclosure provides a thermal-curable adhesive composition and adhesive sheet. The thermal-curable adhesive composition has a rate of change of adhesion ranging from 80% to 98% and defined by the following equation: V=[(V0?V1)/V0]×100, wherein V is the rate of change of adhesion of the thermal-curable adhesive composition, V0 is the adhesion of the thermal-curable adhesive composition under room temperature, and V1 is the adhesion of the thermal-curable adhesive composition after being heated to a predetermined temperature then cooled to the room temperature.

Abstract: The instant disclosure relates to a method for manufacturing a transparent polyimide film, including providing a polyamic acid solution having a fluorine content more than 12%; adding a dehydrating agent and a catalyst into the polyamic acid solution, the dehydrating agent having an equivalent number equal to or larger than 3; and baking the polyamic acid solution under a temperature ranging from 250 to 350° C. for performing a chemical imidization process so that the transparent polyimide film is obtained. The transparent polyimide film has an elongation rate of more than 30% and a b* value in a CIELAB coordinate of less than 3.5.

Abstract: The instant disclosure provides a polyimide composite film for a flexible display and a method for manufacturing the same. The composite film can be attached to a supporting carrier and includes a double-sided tape, a releasing layer and a transparent polyimide film. The double-sided tape includes a substrate, a surface of the substrate has an adhesive disposed thereon, and the other surface of the substrate has a releasing agent disposed thereon. A releasing layer is attached to the adhesive on the substrate and is removable from the substrate so that the substrate is attachable to the supporting carrier through the adhesive. The method includes providing a transparent polyimide film; providing the double-sided tape mentioned above; and removing the releasing layer on the releasing agent of the substrate for adhering the transparent polyimide film to the releasing agent.

Abstract: A method of making a graphite film is provided. The method is characterized in that a polyimide film is used as a precursor, and a carbonizing heat treatment is performed, in which the carbonizing temperature ranges from 500 to 800 degrees Celsius and the heating rate is equal to or lower than 2 degrees Celsius per minute. The highest carbonizing temperature is equal to or higher than 1000 degrees Celsius. The method is also characterized in that the graphitizing temperature ranges from 2200 degrees temperature to the highest graphitizing temperature in which the average heating rate is equal to or lower than 3 degrees Celsius per minute. The highest graphitizing temperature is equal to or higher than 2500 degrees Celsius.