GB1075981A - Process for relaxing synthetic or artificial filamentary material - Google Patents

Abstract

1,075,981. Relaxing filamentary material. AMERICAN CYANAMID CO. March 3, 1965 [Aug. 17, 1964], No. 9125/65. Heading B5B. Synthetic or artificial filamentary material is continuously relaxed by continuously exposing an upwardly moving endless length of the material to turbulent flow of heated gas moving upwardly in the direction of travel of the material in a confined zone at a velocity sufficient to produce adequate turbulence for uniform and effective heat transfer but not sufficient to disarrange or to elongate the material. Such exposure is for a time and at a temperature sufficient to relax but not sufficient to degrade the material. The filamentary material preferably is fed upwardly into the lower portion of the confined zone at a linear velocity which is higher than the linear velocity at which it is removed from the upper portion of the zone, the gas velocity preferably being such as to eliminate tension on the filaments leaving the zone. The material preferably is dry and may be lubricated before being fed into the confined zone; to minimize darkening of the material, antioxidants (examples of which are listed in the Specification) may be applied to the material prior to relaxation. After leaving the confined zone, the filamentary material may be quenched, for example by cold or ambient air or by water, to prevent restretching. The heated gas may, for example, be air; the filamentary material, which may be in the form of a multifilament tow, may be made from polyamides, polyesters, cellulose triacetate or acrylonitrile polymers. Dry acrylic fibres may be relaxed satisfactorily by exposure for from 0À1 to 30, preferably from 0À5 to 5, seconds to a gas heated to a temperature between 250‹ and 600‹ F., preferably between 400‹ and 550‹ F. The relaxation treatment may take place in apparatus described, illustrated and claimed in Specification 1,075,982.