| 摘要 |
<p>1,215,481. Polyimide containing laminates. NATIONAL RESEARCH DEVELOPMENT CORP. 11 April, 1968 [13 April, 1967; 1 Dec., 1967], Nos. 17116/67 and 54823/67. Heading B5N. [Also in Division C3] Soluble fusible prepolymers are prepared by reacting an aromatic tetracarboxy compound with an N,N<SP>1</SP>-diacyl derivative of an aromatic diprimary amine, in bulk or in a diluent which is a monocarboxylic acid or anhydride, with elimination of carboxylic acids or esters. Acetylation of the diamine may be effected in situ in the diluent prior to addition of the carboxy reactant. Numerous reactants are specified. The prepolymer, or a solution thereof, e.g. in tetrahydrofuran, acetic acid or anhydride, chloroform, acetone or ethylacetate, may be used to impregnate a matrix of filler or fibre reinforcing materials, e.g. glass fibre, asbestos, carbon fibre, or polyimide powder, which is then cured with further heat and pressure. Laminates may be prepared by pressing layers of impregnated fibre at 200‹ to 300‹ C. and 200 to 1000 p.a.i. with post-cure at up to 450‹ C. Alternatively the fibres may be covered with the initial reactants. Reference is made to Specification 570,858.</p> |
