Patent GB-858534-A (GB)
Title: Improvements relating to the treatment of cellulose triacetate fibres
Inventor: WYLDE JOSEPH ROWLAND
IPC: D02G1/00
Filed: 1956-09-06
Abstract: A yarn or like textile product containing fibres of cellulose triacetate is subjected while the fibres are in a crimped condition or are being crimped and in the presence of a carboxylic ester of a di- or polyhydric alcohol to the action of heat.  The ester may be the ester of a fatty acid containing 1-4C or the ester may be an alkyletherester wherein the alkyl radical preferably contains 1-4C. Specified esters are diethylene glycol diacetate, diethylene glycol monoacetate, dipropylene glycol diacetate, glycerol diacetate, glycerol triacetate and diethylene glycol monoethyl-ether-acetate. Preferably the ester has a boiling point of above 190 DEG C.  Steam may be the source of heat and is preferably used in conjunction with an aqueous solution of a water-miscible ester.  A continuous filament yarn or tow may be passed through a bath containing an aqueous solution of diethylene glycol diacetate whence it is directed to the feed rollers of a heated stuffer box.  Alternatively, the yarn or tow may be impregnated with the ester directly or an aqueous solution thereof and subjected to the action of steam supplied to the interior of the stuffer box under pressure.  When the ester is insufficiently miscible with water for the desired strength of solution to be applied a volatile water-miscible liquid e.g. methyl, ethyl or isopropyl alcohol may be added to obtain homogeneity.  On emergence from a stuffer box tows of up to 10,000 denier may be drafted before being twisted into yarns. Instead of a stuffer box, crimping rollers having gear teeth may be used to impart crimp to the fibres of the yarns, the heat treatment being administered during their passage through the rollers and/or subsequently.  Again, the fibres may be heated while being distorted by means of co-operating racks, toothed belts, sets of interdigitating pins or like means.  The fibres of the yarn or like textile product may be subjected to a temporary twisting operation (e.g. false twist), the distortions imposed upon the fibres by such twist being set in the fibres by heat treatment and retained in the fibres after the twist has been removed.  After crimping, the yarn or like material containing the crimped fibres may be washed to remove the ester, subjected to such treatments as twisting, cutting or otherwise converting into staple fibres for spinning into yarn, weaving, knitting and netting and at any stage in such treatments may be dyed or otherwise. finished Examples are given.  Specifications 696,761, 845,752 and 852,729 are referred to.ALSO:A yarn or like textile product containing fibres of cellulose triacetate is subjected while the fibres are in a crimped condition or are being crimped and in the presence of a carboxylic ester of a di-or polyhydric alcohol to the action of heat.  The ester may be the ester of a fatty acid containing 1-4C or the ester may be an alkylether-ester wherein the alkyl radical preferably contains 1-4C. Specified esters are diethylene glycol diacetate, diethylene glycol monoacetate, dipropylene glycol diacetate, glycerol diacetate, glycerol triacetate and diethylene glycol monoethyl-ether-acetate. Preferably the ester has a boiling point above 190 DEG C.  Steam may be the source of heat and is preferably used in conjunction with an aqueous solution of a water-miscible ester.  A continuous filament yarn or tow may be passed through a bath containing an aqueous solution of diethylene glycol diacetate whence it is directed to the feed rollers of a heated stuffer box.  Alternatively, the yarn or tow may be impregnated with the ester directly or an aqueous solution thereof and subjected to the action of a steam supplied to the interior of the stuffer box under pressure.  When the ester is insufficiently miscible with water for the desired strength of solution to be applied a volatile water-miscible liquid, e.g. methyl, ethyl or isopropyl alcohol may be added to obtain homogeneity.  On emergence from a stuffer box tows of up to 10,000 denier may be drafted before being twisted into yarns.  Instead of a stuffer box, crimping rollers having gear teeth may be used to impart crimp to the fibres of the yarns, the heat treatment being administered during their passage through the rollers and/or subsequently.  Again, the fibres may be heated while being distorted by means of co-operating racks, toothed belts, sets of interdigitating pins or like means. The fibres of the yarn or like textile product may be subjected to a temporary twisting operation (e.g. false twist), the distortions imposed upon the fibres by such twist being set in the fibres by heat treatment and retained in the fibres after the twist has been removed.  After crimping, the yarn or like material containing the crimped fibres may be washed to remove the ester, subjected to such treatments as twisting, cutting or otherwise converting into staple fibres for spinning into yarn, weaving, knitting and netting and at any stage in such treatments may be dyed or otherwise finished. Examples are given.  Specifications 696,761, 845,752 and 852,729 are referred to.