| 摘要 |
Novel polymer blends are disclosed comprising about 10 to 95 percent by weight of a copolyimide (A) prepared from benzophenone-3,3',4,4'-tetracarboxylic acid dianhydride and a mixture of 4,4'-methylenebis(phenyl isocyanate) and toluene diisocyanate (2,4- or 2,6-isomer or mixtures thereof) with the isocyanates used in a molar percent ratio from about 10/90 to 30/70 respectively; and from about 90 to 5 percent by weight of a copolyamideimide (B) prepared from 4,4'-methylenebis(phenyl isocyanate) and a mixture of trimellitic anhydride and isophthalic acid with the acid components used in a molar percent ratio from about 70/30 to 90/10 respectively. The novel blends may be used in the form of their dry blend or in solution and the films produced therefrom are characterized by improved elongation and tear strength values over those for the copolyimide (A) alone. Furthermore, the softening point of the blends is increased over the copolyamideimide alone.
|
