GB679182A - Improvements in and relating to the production of artificial threads from viscose - Google Patents

Abstract

Viscose is extruded into a coagulating bath and the so-formed thread is subjected without a break to a series of treatments and to drying and winding on to a package, one of the treatments prior to drying comprising the application to the surface of the untwisted thread of an adhesive which improves the bonding of the threads to rubber in the manufacture of composite textile-rubber articles. Suitable adhesives include aqueous solutions or dispersions of heat-hardening resin-forming condensates of phenols and aldehydes, solutions of trimethylolphenol and dimethylolcresol, a solution of the alkali-soluble condensation product of a phenol and sulphur, a solution of the permanently fusible, alkali-soluble condensate of an aldehyde and a mono- or di-hydric phenol, a solution of a protein such as casein or a solution containing two or more of these compounds. The threads may be stretched after leaving the coagulating bath. If desired a lubricant (mineral oil, sulphonated mineral oil or cetyl sodium sulphate) <PICT:0679182/IV (a)/1> may be applied simultaneously with the adhesive or to the dried coated thread before winding on to the package. As shown, suitable apparatus comprises a spinning jet 2 through which viscose is extruded into a coagulating bath 3. The untwisted filaments are drawn by a godet 4, then through a treatment bath 5 to a second godet rotating at a higher peripheral speed than godet 4. In the bath 5 a treatment liquid such as hot dilute acid passes in countercurrent to the thread 7. The thread is then led to reel 8 on which it is treated with an acid wash supplied by pipe 18, any excess being collected in the drip tray 19 beneath the reel. The thread then passes to reel 9, on which it is washed with water, to reel 10, where no treatment is applied, any surplus liquid being allowed to drip off into tray 22, and to reel 11, where the solution or dispersion of the adhesive is applied by pipe 23. The thread is finally dried on reel 13 heated internally by steam supplied through the hollow driving spindle 25, and wound on the capspinning device 14. The drying roller may be supplied with a scraper to remove any adhesive deposited thereon. In an example (all parts by weight) viscose containing 7.4 per cent of cellulose is extruded into a coagulating bath containing 9.5 per cent of sulphuric acid, 4.0 per cent zinc sulphate and 20 per cent sodium sulphate. The 500-filament untwisted thread obtained is led through a bath containing 1.5 per cent sulphuric acid, 3 per cent sodium sulphate and 0.4 per cent zinc sulphate at 95 DEG C. and stretched 86 per cent. The stretched thread is led to the first of a series of thread-advancing reels, on which it is washed with an aqueous solution containing 1 per cent sulphuric acid, 2.5 per cent sodium sulphate and 0.1 per cent zinc sulphate. On the second reel it is washed with water at 50 DEG C. No treatment is given on the third reel. On the fourth reel it is treated with a 2 per cent solution of the permanently-fusible, alkali-soluble condensation product of resorcinol and formaldehyde. The coated thread is dried on steam heated rollers and lubricated by contact with a wick coated with mineral oil and then collected on a cap spinning device. Details are given of a test for estimating the adhesion of the treated cords to rubber. Specifications 413,414, [Group IX], 467,500, 477,380, 501,603, 581,616, 598,147 and 618,705, [Group V], and U.S.A. Specification 2,294,870 are referred to. The Provisional Specification refers also to Specification 632,109, [Group IV (c)].