Patent GB-604163-A (GB)
Title: Improvements in or relating to the production of artificial staple fibre
Filed: 1945-11-05
Abstract: A composition to be used for lubricating filaments of organic derivatives of cellulose comprises 75 per cent of a mineral oil of about 50-100 Saybolt viscosity together with 8-10 per cent of sulphonated vegetable oil such as olive or peanut oil, 7-8 per cent of unsulphonated vegetable oil, 3-4 per cent oleic acid, 2 per cent of a soap such as sodium oleate and 1 per cent water.ALSO:The production of staple fibres of an organic derivative of cellulose which are readily amenable to textile dressing comprises the application of one of the substantially non-aqueous sulphonated conditioning agents as claimed in Specification 574,072 to continuous filaments of the organic cellulose derivative which are already carrying a lubricating oil, and thereafter cutting the continuous filaments into staple fibre lengths.  The process is applicable to cellulose acetate, propionate and butyrate, mixed esters such as cellulose acetatepropionate and acetate-butyrate, and to cellulose ethers such as ethyl and benzyl cellulose.  The filaments are lubricated immediately on leaving the spinning cabinet by being led over a rotating wick dipping into the lubricant.  About 0.25 to 3 per cent of the lubricant may be applied to the filaments, but about 0.75 per cent (of the weight of the filaments) is preferable.  The lubricating agent may comprise 75 per cent of a mineral oil of about 50-100 Saybolt viscosity together with 8-10 per cent of sulphonated vegetable oil such as olive or peanut oil, 7-8 per cent of unsulphonated vegetable oil, 3-4 per cent oleic acid, 2 per cent of a soap such as sodium oleate and 1 per cent of water. The soap and water render the lubricating agent self-emulsifying so that it can be scoured easily from the fibres at a later stage in the processing. The lubricated filaments are gathered together into a tow and treated with the substantially non-aqueous sulphonated conditioning agent which may be sprayed directly on to it or may be fed on to it in the form of a controlled thin stream. The conditioning agent not only improves the handle of the filaments but prevents the generation of large amounts of static electricity.  It may be prepared by reacting 20 per cent oleum with a mixture of oleic acid, vegetable oil and mineral oil, and then adding a penetrating agent such as diamyl phenol.  Free acid is neutralized by the addition of aqueous alkali and triethanolamine, and in addition a fungicide such as sodium orthophenyl phenate may be added (see Specification 574,072). The conditioning agent is preferably employed at an elevated temperature. The filaments may be crimped immediately after treatment with the sulphonating agent.  In an example a 25 per cent solution of cellulose acetate of acetyl value about 54 per cent in 95 per cent aqueous acetone is dry spun to form a 120 denier, 40 filament yarn. The yarn leaving the base of the spinning cabinet passes over a rotating wick partly submerged in a vessel containing a lubricating agent comprising a mineral oil together with emulsifying agents which render the lubricant self-scouring when the yarn is immersed in water.  0.75 per cent of the lubricating agent is applied to the yarn.  A number of lubricated yarns are gathered into a tow of 30 ends and passed through a pair of rolls which forces the yarn into a crimping chamber.  A controlled stream of substantially non-aqueous sulphonated conditioning agent heated to 50 DEG  C. is fed on to the moving tow just prior to entering the crimping rolls, the rate of feed being such that about 0.45 per cent by weight of the finish is placed on the tow.  Back pressure in the chamber places a permanent crimp in the yarns.  The crimped tow is drawn from the chamber and cut into staple fibre by means of a centrifugal cutter.  The staple lengths are dried in a continuous drier at 95 DEG  C. to a final moisture content of about 6 per cent.