| 摘要 |
PROBLEM TO BE SOLVED: To provide a novel polyimide resin binder which can be applied to give a nonwoven fabric which has heat resistance and such high shape retention that it undergoes no marked reduction in tensile strength even when left in an atmosphere of 200°C or higher and which can be used in a state of an aqueous solution when it is mixed with heat-resistant fibers and to provide a heat-resistant nonwoven fabrics using the same. SOLUTION: Provided is a binder resin which can be applied to form a heat-resistant nonwoven fabric and comprises a polyimide obtained from a water-soluble polyimide precursor containing a polyamic acid obtained from a tetracarboxylic acid component containing not less than 50% 2,3,3',4'-biphenyltetracarboxylic acid component and an aromatic diamine and 1,2-dimethylimidazole and/or 1-methyl-2-ethylimidazole in an amount of at least 0.9 mol per mol of the carboxyl groups of the polyamic acid. COPYRIGHT: (C)2008,JPO&INPIT |
