Recycling ammonium hydroxide-treated water in the production of polyacrylonitrile fibers

摘要

1,027,132. Vinyl polymer filaments. MONSANTO CO. Aug. 17, 1964 [Aug. 27, 1963], No. 33521/64. Heading B5B. In a process for the preparation of fibres from vinyl polymers wherein a vinyl polymer is dissolved in a solvent and the resulting homogeneous solution is extruded into a coagulating medium to form fibres, the fibres are washed with an acid-contaminated aqueous solution that has been treated with ammonium hydroxide. Such a solution may be water used. in the coagulation of the fibres, containing, before treatment, 0À01-0À10% by weight of acetic acid. Enough ammonium hydroxide may be added to give a pH of 7À0-10À0. The vinyl polymer may be polyacrylonitrile, copolymers and blends thereof containing as little as 35% acrylonitrile, or copolymers or blends containing a major amount of other vinyl compounds such as vinyl chloride, vinylidene chloride, and styrene. The ammonia may be added to the acid-contaminated water at any time prior to the washing of the fibre, and may be added as ammonia gas, liquid ammonia, or in any form that will result in the formation of ammonium hydroxide. The dye receptivity of the fibres is improved, and corrosion of textile processing equipment caused by contact with the fibres is reduced.