| 摘要 |
<p>A textile fibre drafting element, e.g. a drafting apron, spinning roll or roll cover, has a surface of a rubber-like conjugated diene polymer or copolymer which has been modified by reaction with an aqueous solution of sulphuric acid containing dichromate ions, the concentration of the sulphuric acid being at least 1 per cent. but not sufficient to effect substantial deterioration of the rubber-like material, and its dichromate ion concentration being at least 0.01 mol. per litre. The treatment may be carried out before or, preferably, after vulcanization. Specified rubber-like materials, are polychloroprene, polyisoprene, polybutadiene, and copolymers of butadiene with styrene, acrylonitrile or acrylic esters. Specified dichromate ion substances are potassium dichromate, ammonium dichromate and sodium dichromate. It is preferred that the aqueous solution contains 1 to 25 per cent. sulphuric acid and from 0.01 to 0.5 mols. per litre of dichromate ion. Specification 643,666 is referred to.</p> |
