| 摘要 |
<p>1414651 Acrylonitrile fibres and films E I DU PONT DE NEMOURS & CO 16 Oct 1972 [14 Oct 1971] 47646/72 Heading B6B [Also in Division C3] An extrudable substantially single-phase polymer composition particularly useful for forming filaments and films comprises an acrylonitrile polymer containing at least 40% by weight acrylonitrile units and water, the water present being completely or partially in the form of a hydrate with the nitrile groups of the polymer. The composition is prepared by heating the polymer under at least autogenous pressure with sufficient water to hydrate at least 45% of all the nitrile groups or at least 80% of the coupled nitrile groups to a temperature at which hydration takes place. In examples polyacrylonitrile and copolymers of acrylonitrile with one or more of methylacrylate, sodium styrene sulphonate, styrene, ethylene, 2-methyl-5-vinyl pyridine and vinyl acetate are heated to temperatures from 140-205‹ C. and the compositions are extruded to form filaments and films. Films may be stretched by inflation using steam to produce the internal pressure, and the product has a layered structure in which an inner core of material containing voids is interposed between layers having no voids and the density which is higher than that of the core. Those filaments wherein the acrylonitrile polymer contains at least 80% by weight of acrylonitrile units form the subject of divisional Specification 1,414,652.</p> |
