| 摘要 |
<p>1488573 Curable amino-prepolymer compositions CIBA-GEIGY AG 3 Jan 1975 [4 Jan 1974] 293/75 Heading C3R A heat-curable composition comprises (a) a prepolymer terminated substantially only by primary amino groups and derived from monomer units which can be polymerized to a polymer which is thermally stable at 250‹ C. (i.e. it neither loses its mechanical properties nor suffers chemical degradation), and (b) a cyanamide of a polyfunctional secondary amine, the ratio of NH 2 groups in (a) to cyanamide groups in (b) being from 2 : 1 to 1 : 5. It is stated that (b) is a reactive flux for the prepolymers which lowers their softening temperature permitting them to be used in conventional plastics processing techniques, e.g. autoclave and vacuum bag laminating or compression or injection moulding, but participates in the curing by chain-extending and cross-linking them without by-products causing voids. The thermallystable recurring units in (a) may be those of a polyamide-imide, polyimide, aromatic polyamide, polybenzimidazole, polypyrrone, polythiadiazole, polyquinoxaline, polybenzothiazole, polyarylenesulphone or polyphenylene sulphide or of a precursor thereof, e.g. a polyamideacid. Numerous examples of such components are given; (b) is preferably N,N<SP>1</SP>-dicyanopiperazine or tris-(N-cyanoanilino)-s-triazine. Reference is made to Specification 1,425,241.</p> |
