METHOD OF PRODUCING SOIL RESISTANT ACRYLIC FIBERS

摘要

1,246,014. Producing soil resistant polyacrylonitrile fibres. MONSANTO CO. 16 Jan., 1969 [16 Jan., 1968], No. 2580/69. Heading B5B. Polyacrylonitrile textile fibres are treated to render them soil resistant by applying to the wet spun fibres a first finish composition, containing compounds selected from the group consisting of textile lubricants, softeners, antistats, and mixtures thereof, heating and partially drying the fibres, applying to the partially dried hot fibres a soil resistant finish composition containing a zirconium salt in an acidic aqueous solution, and finally drying the fibres to a moisture content of less than 0À5%. The fibres may be partially dried by applying to them sufficient heat to increase their surface temperature to a level higher than about 70‹ C. The partially dried fibres may have a moisture content of less than about 55% and more than about 5%. The fibres may contain at least 80% acrylonitrile. They may consist of a copolymer of at least about 80% acrylonitrile and up to about 20% of at least one other vinyl monomer such as vinyl acetate. The second finish composition may contain, in addition to the zirconium acetate, sulphamic acid. In an example, a spinning solution comprised of 26 parts by weight of a polymer consisting of 93% acrylonitrile and 7% vinyl acetate, 74 parts of dimethyl-acetamide solvent, and 0À45% based on polymer weight of TiO 2 delusterant is wet spun into an aqueous coagulation bath containing 55% of the solvent and maintained at 40‹ C. The filaments are withdrawn from the bath, simultaneously washed free from solvent with boiling water and stretched at a stretch ratio of 6. The filaments are then passed through a bath of an aqueous solution of a conventional finish comprising 66% by weight of a lubricating agent containing 60% sorbitan monopalmitate and 40% of castor oil fatty acid with 200 moles of ethylene oxide and 34% of an antistatic agent consisting of soya dimethylaminoethyl etho sulphate. After leaving the finish bath and being stripped of excess finish, the filaments are passed around drying rolls heated to about 150‹ C. with steam. The moisture content of the filaments is thereby reduced to about 20% and their surface temperature increased to about 83‹ C. As the tow of filaments proceeds from the last drying roll it is sprayed with a second finish containing in aqueous solution a combination of the first finish and a soil-resistant finish comprised of zirconium acetate and sulphamic acid. The moisture content of the tow is then reduced to about 0À2% by passing it over further drying rolls.