| 摘要 |
1,147,515. Laminates; polyamide acid films. E. I. DU PONT DE NEMOURS & CO. 6 Dec., 1966 [6 Dec., 1965 ; 10 March, 1966], No. 54477/66. Headings B5B and B5N. [Also in Division C3] Glass fibre laminates and self-supporting films may be prepared using a composition comprising 1-60% by weight of a polyamide acid in an organic liquid which is either (1) acetone or dimethyl phthalate, (2) a mixture of (i) a polar solvent or swelling agent and (ii) a miscible non- solvent which is more volatile than the solvent and contains a carbonyl or thiocarbonyl group, or (3) a mixture of (1) and (2). In Example 1 a polyamide acid from bis(aminophenyl) methane and benzophenone tetracarboxylic acid dispersed in acetone is applied in stripes to glass fabric which has been previously impregnated with a polyimide from benzophenone tetracarboxylic acid diester and m-phenylene diamine. When plies of this fabric are laminated the product may be pulled out to a honeycomb structure. In Example 2 the acetone is replaced by a mixture of N-methyl-pyrrolidone and methyl isobutyl ketone. In Example 3 the dispersion of Example 2 is cast on a smooth substrate, dried and heat cured to form a selfsupporting film. In Example 4 a polyamide acid from benzophenone tetracarboxylic anhydride and bis(aminophenyl) methane dissolved in dimethyl o-phthalate is cast on a copper substrate and dried to smooth uniform film. |
