Manufacture of regenerated cellulosic fiber by zinc free viscose process
First Claim
1. A process for the production of regenerated cellulose fibre having increased lustre and softness and having substantially "C" cross section with well developed skin which comprises soaking a rayon grade pulp in caustic soda solution of 17.5 to 18.5% to produce alkali cellulose having 33-34% cellulose and 15.55 to 16.00% sodium hydroxide, shredding the alkali cellulose, aging same to get a viscous solution having viscosity of 35-75 ball fall seconds, converting the alkali cellulose into cellulose xanthate by reaction with 28 to 33% carbon-di-sulphide, preparing a viscose solution from the xanthate by dissolving same in dilute caustic soda solution, said viscose solution having 6-11% cellulose and 52-60% caustic soda/cellulose, allowing the viscose solution to ripen and thereafter subjecting the ripened solution to spinning in a spin bath containing 6.5-12% sulphuric acid, 0.3-2.0% aluminium sulphate [(Al2 (SO4)3)] and 18-26% sodium sulphate followed by stretching the spun filament and thereafter, regenerating, desulphurizing, bleaching, finishing and drying the filament in a conventional manner.
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Accused Products
Abstract
A process for the production of rayon fibers. The viscose solution is spun into a spinbath which is acidic in character but has no zinc salt like conventional baths. The spin bath contains sulphuric acid, aluminum sulphate and sodium sulphate. The spinning is at temperatures of 35°-60° C. Usual stretching and post spinning operations are carried out as necessary. The regenerated cellulose fibers obtained are of novel cross-sections, namely of `c` cross section not achieved ever before. The fibers exhibit increased luster and softness.
8 Citations
2 Claims
- 1. A process for the production of regenerated cellulose fibre having increased lustre and softness and having substantially "C" cross section with well developed skin which comprises soaking a rayon grade pulp in caustic soda solution of 17.5 to 18.5% to produce alkali cellulose having 33-34% cellulose and 15.55 to 16.00% sodium hydroxide, shredding the alkali cellulose, aging same to get a viscous solution having viscosity of 35-75 ball fall seconds, converting the alkali cellulose into cellulose xanthate by reaction with 28 to 33% carbon-di-sulphide, preparing a viscose solution from the xanthate by dissolving same in dilute caustic soda solution, said viscose solution having 6-11% cellulose and 52-60% caustic soda/cellulose, allowing the viscose solution to ripen and thereafter subjecting the ripened solution to spinning in a spin bath containing 6.5-12% sulphuric acid, 0.3-2.0% aluminium sulphate [(Al2 (SO4)3)] and 18-26% sodium sulphate followed by stretching the spun filament and thereafter, regenerating, desulphurizing, bleaching, finishing and drying the filament in a conventional manner.
Specification
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- Resources
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Current AssigneeBirla Research Institute For Applied Science
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Original AssigneeIndubhai H. Parekh, Sunanda K.R. Moulik
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InventorsMoulik, Sunanda K. R., Parekh, Indubhai H.
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Primary Examiner(s)Tentoni, Leo B.
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Application NumberUS08/055,524Time in Patent Office544 DaysField of Search264/188, 264/195, 264/198, 264/177.13, 8/101, 106/165, 536/30, 536/60US Class Current264/177.13CPC Class CodesD01F 2/08 Composition of the spinning...
