| 摘要 |
1,175,555. Coating. SUMITOMO ELECTRIC INDUSTRIES Ltd. 18 Jan., 1967 [25 Jan., 1966; 11 June, 1966], No. 2589/67. Heading B2K. [Also in Division C3J Polyamide-imide solutions are prepared by heating a tricarboxylic acid anhydride with a diisocyanate or mixture thereof with a higher poly-isocyanate in a solvent for the polyamideimide. Various solvents and diluents are specified. In Examples solutions are prepared from trimellitic anhydride and diphenylmethane-4, 4<SP>1</SP>-disocyanate, with or without a commercial polymethylene polyphenylene isocyanate, or a mixture of 2, 4 and 2, 6 tolylene diisocyanate in various solvents. The solutions are useful for heat-resisting insulating varnishes, films, magnet wires, laminated boards and laminated tubes. In Examples the products are used to cast flexible transparent film on to enamel copper wire by application to 1 mm wire which is then passed at 8 m/minute through an electric furnace at 450‹C. |
