| 摘要 |
1,240,666. Laminate. MINNESOTA MINING & MFG. CO. 11 Nov., 1969 [12 Nov., 1968], No. 55150/69. Addition to 1,240,665. Heading B5N. [Also in Division H1] The metal-polyimide composites claimed in the parent Specification, which comprise layers of metal and of a polymer obtained by curing a composition comprising a solution in a volatile solvent of a mixture of separately prepared polyamide acids the first being prepared from a tetracarboxylic acid and the second, which provides up to 90% total solids, from a tricarboxylic acid, with the polymer portion of the composite forming a flexible adherent dielectric film which is self-supporting if the metal is etched away, is modified by having a heatresistant porous web-like backing carried by and at least partially embedded in at least one of the polymer layers of the composite. Specified web-like backings are glass fibre or cloth and polyamide, e.g. polymetaphenylene diamine isoterephthalamide, fibre or cloth. In examples, starched 2 mil. glass cloth or polyamide cloth is dipped in the polyamide acid solution and laminated to the oxidized surface of electrolytic copper foil. |
