Fasern und Faeden und ihre Herstellung

摘要

1,259,788. Poly(p-phenylene terephthalamide) films. E. I. DU PONT DE NEMOURS & CO. 24 Dec., 1968 [27 Dec., 1967], No. 61488/68. Heading B5B. [Also in Division C3] Fibres of a synthetic polycarbonamide comprise a homopolymer or copolymer containing at least one type of recurring unit having the general formula wherein Ar 1 and Ar 2 may be p-phenylene, 2 (or 3)-chloro-p-phenylene, 2,6(or 3,5)-dichloro-pphenylene and 2,5(or 3,6)-dichloro-p-phenylene. The fibres have an initial modulus in excess of 170 grams per denier and an orientation angle of up to 40 degrees. The fibres may already have these properties before they are treated after the spinning step, or may have the properties imparted to them by heating them while they are under tension or being drawn. In the latter treatments the fibres are stretched at a draw ratio of 1À01 to 1À5, e.g. using a pin or plate and are heated within the range of about 200- 650‹ C., preferably 300-600‹ C., e.g. in a nitrogen atmosphere. The fibres may be formed by dry or wet spinning (by conventional methods) a dope comprising a polymer of the type defined above having an inherent viscosity of 1 to 2À6, an organic liquid and an inorganic salt in such proportions that the dope is optically anisotropic. In wet-spinning, suitable coagulants include water, ethylene glycol, glycerol, mixtures of water and N,N,N1,N1-tetramethyl urea, isopropanol, mixtures of water and alcohol, and aqueous salt baths. The salt may be lithium chloride or calcium chloride. The dope may comprise 5-25% by weight of the polymer, 0À5-8% by weight of lithium chloride or calcium chloride, and from 67 to 94À5% by weight of one or more of the following liquids: hexamethylphosphoramide, N-methylpyrrolidone-2,N,N-dimethyl-acetamide, N,N,N1,N1-tetramethylurea and tetramethylene sulphoxide. The terms "initial modulus" and "orientation angle" are defined.