| 20090061096 | SMALL BLOCK COPOLYMER OF POLYIMIDE - A method of making a block polyimide copolymer containing a first small block copolymer segment and a second larger block segment includes the steps of (a) reacting a first aromatic acid dianhydride with an aromatic diamine in a molar ratio from about 10:100 to about 50:100, respectively, to obtain the small block copolymer, (b) reacting the small block copolymer and excess amount of diamine with a second acid dianhydride in such a quantity that a total aromatic acid dianhydride and a total aromatic diamine are equimolar to obtain a precursor solution containing the first small block copolymer segment and the second larger block segment, (c) forming a film, laminate, or coating on a substrate, and (d) cyclodehydrating the film, laminate, or coating by chemical or thermal imidization. | 03-05-2009 |
