| 摘要 |
Fabrics or fleeces made from regenerated cellulose filaments or fibres made by (1) the process of the Parent Specification, the salt being of Fe or Pb, are thereafter (2) reacted in the presence of OH- ions with a salt of a heavy metal having greater affinity for S= in alkaline environment than Fe or Pb; and (3) the Fe or Pb hydroxides are then reconverted by S= to the sulphide; these reactions being repeated any number of times. In step (1) viscose containing a dissolved compound of As or Sb is extruded into a bath containing H2SO4, Na2SO4, and optionally ZnSO4; the filaments or fibres are then treated with aqueous Fe or Pb salts which react with the As or Sb sulphides to form Fe or Pb sulphides. With PbS, the salt in reaction (2) may be of Hg, Ag or Cu whereas with FeS, salts of Pb, Sn, Cd, Co, Ni and Zn may also be used. Preferably the salt in step (2) is of a metal with an amphoteric hydroxide, e.g. Cd, Zn, Cu or Ag. The reaction (2) may be performed in ammoniacal solution, the salts used being ammonium or amine complexes. Strong base/weak acid buffer salts, e.g. sodium acetate, may be present, and the heavy metal salts may be acetates. In step (3), the source of S= may be H2S gas or sulphide solutions. The heavy-metal content of the treated material may be more than 50% by weight. The textiles obtained, which are water-repellent, may be used for protective clothing for high energy radiation. |
