Process for fiacao in merger with articles formed of polymeric refratario, article conformed; and fiber polymer of acrylonitrile

摘要

1452400 Melt spinning refractory polymers AMERICAN CYANAMID CO 22 Jan 1974 [5 Feb 1973 2 March 1973 23 March 1973 10 April 1973 5 July 1973] 02985/74 Heading B5B Shaped articles including filaments and films, are prepared by extruding a single phase fusion melt of a refractory polymer esp. acrylonitrile, but also other high melting point polymers, and a melt assistant i.e. a substance which is capable, when used under pressure sufficient to prevent boiling at temperatures above its atmospheric boiling point, of reducing the melting point of the refractory polymer to a temperature below the degradation range of the polymer, other than normal solvents for the polymer, at a temperature Tf which is above the single phase melt melting point temperature M and also above the boiling point at atmospheric pressure of said melt assistant through a spinnerette directly into a pressurized solidification zone wherein the following conditions obtain (1) there is a partial pressure of melt assistant such that the composition profile across the crosssection of the nascent extrudate so produced remains relatively flat: (2) the concentration of melt assistant retained in said nascent extrudate remains at a value at least 70% of the concentration of melt assistant in said single phase fusion melt, and (3) the temperature of the nascent extrudate is below said temperature Tf but not lower than 20‹ C. below said temperature M. Preferred melt assistants are 1-4C-alkanols, acetonitrile, formic or acetic acids, water or a dilute solution of an inorganic salt in water, the solution being too dilute to act as a solvent for acrylonitrile. Thus a blended mixture of polymer and melt assistant is extruded through a spinnerette 12 into a pressurized chamber 13 and the filaments 21 are drawn under tension by a rotary godet or thread advancing rolls 22 and then wound up on yarn package 30 or relaxed in a steam chamber 33 prior to wind up.