| 摘要 |
Crimped regenerated cellulose staple fibres of improved absorbency and resistance to loss of interfibre volume are made by reacting cellulose pulp containing not more than 0,05% by weight of ether-extractable solids, preferably 0,01%-0,05%, with caustic soda containing not more than 0,8% by weight of hemicellulose, preferably not more than 0,7%, xanthating, dissolving the cellulose xanthate in caustic soda free of hemicellulose to form viscose, regenerating the viscose in a bath comprising between 5% and 8%, preferably 6,5%-7,0%, by weight of sulphuric acid to form filaments, stretching the filaments between 60% and 85%, preferably 70%-80%, in the bath, and cutting the filaments to staple fibre length, preferably between 1 and 2 inches, and especially about 1 1/8 inches. The regenerating bath may also contain about 15%-22% by weight of sodium or potassium sulphate and about 0,75%-1,5% of zinc sulphate. The staple fibres may be washed in fresh water and bleached in a solution of a soluble hypochlorite in amount sufficient to yield 0,1%-0,3% by weight of available chlorine at pH 9-12. A solution containing 0,175% of sodium hypochlorite may be used for this purpose. The staple fibres may be finished in a solution containing 0,01%-0,3% by weight of a polyoxyethylene monoether of sorbitan monolaurate containing about 20 ethylene oxide units per mole. A preferred finishing solution contains 0,18% by weight of the said sorbitan derivative and about 0,4% of sodium bisulphite at a pH of about 5,0. Regenerated cellulose staple fibres are obtained having a denier of 1 to 5,5 and crimps comprising helical bends numbering per inch at least 19 times the square root of the reciprocal of their denier, and capable of retaining their crimps when wet and relaxed. Such fibres have, per 1,5 grams, an interfibre volume of at least 1,75 cubic inches in the dry state and of at least 1,00 cubic inch in the wet state, both measurements being made when the fibres are subjected to a pressure of 0,5 pounds per square inch. The fibres can absorb between 26 and 35 times their weight of water. Desirably, the number of crimps per inch is 19 to 35 times the square root of the reciprocal of the denier, preferably 24 to 32 and especially 26 to 28 times, these lastmentioned fibres being able to absorb 26 to 28 times their weight of water. Specification 800,199 is referred to. |
