Verbesserte Polyxylylenadipinamidfasern und Verfahren zu ihrer Herstellung

摘要

1,231,629. Producing polyxylyleneadipamide filaments. TOYO BOSEKI K.K. 19 Dec., 1968 [19 Dec., 1967], No. 60528/68. Heading B5B. A process for the production of hot stretched polyxylyleneadipamide filaments comprises melt-spinning a condensation polymer of metaxylylenediamine with adipic acid, of a mixed meta / para - xylylenediamine containing less than 30 mol. per cent of the para compound with adipic acid, to form filaments, quenching the freshly extruded hot filaments with a stream of cooling gas having a velocity of less than 1À0 m./sec. to obtain unstretched filaments, the birefringence (#n) of which satisfies the relationship : in which X represents the molar percentage of the para compound in the diamine mixture, and the unstretched filaments are then stretched at an elevated temperature. The birefringence (#n) may be controlled by carrying out the melt-spinning step under conditions which satisfy the formula in which V represents the take-up velocity of the unstretched filaments in m./min., Q represents the rate of extrusion of the molten polymer in grams per mm2. (of the sum of the crosssectional areas of the extrusion orifices of the spinneret) per minute, V/Q is 12 to 120, Mw represents the average molecular weight of the polymer within the range 15,000 to 30,000 and T represents the spinning temperature in ‹C. The melt-spinning temperature (T ‹C.) may satisfy the formula The filaments may be stretched while maintaining their water content below 4%, e.g. at about 3%. The molten polymer to be spun may contain 10 to 1000 p.p.m. of hypophosphorous acid or of a metal salt thereof and/or may contain 0À05 to 0À7 mol./kg., based upon the weight of the polymer, of a monohydric or a polyhydric aliphatic alcohol, a phenol, a cycloalkanol or a saccharide or of any mixture thereof. The polymer to be melt-spun may satisfy the relationship in which # rel represents the relative viscosity of the polymer at 25‹ C. with respect to a solution of 1 gram of the polymer in 100 ml. of 96% sulphuric acid, and r is the mol. ratio of a xylylenediammonium adipate salt component in the polymer and is defined as follows: In addition the polymer may satisfy the formula (Ts/T100) = 0À70 in which Ts represents the area below and T100 is the area below the transmission curve plotted against the wavelength between 340 to 800 mÁ as measured in a 10 mm. quartz cell with respect to the polyxylyleneadipamide solution (concentration 20 g./ 100 ml. solvent; formic acid). The term "viscosity stabilizer is defined as a chain modifier or terminator such as a mono basic or a mono acidic amine, a dibasic acid or a diacidic diamine.