Verfahren zur Aufhellung und zur Verhinderung der Vergilbung von Proteinfasern durch Sonnenlicht

摘要

1,178,933. Treating protein fibres. COMMONWEALTH SCIENTIFIC & INDUSTRIAL RESEARCH ORGANIZATION. 4 Oct., 1967 [4 Oct., 1966], No. 45218/67. Headings D1B and D1P. Protein fibres, e.g. wool or silk in the form of fabric or slubbing, are whitened and/or their sunlight yellowing is retarded by a process comprising the steps of (a) treating them with thiourea or a derivative thereof, e.g. N-methylthiourea, N,N'-dimethylthiourea, ethylenethiourea, a methylol thiourea or a disulphide of thiourea, and at least two of the steps of (b) treating them with formaldehyde or a source of formaldehyde, e.g. paraformaldehyde, dimethylol ethyleneurea, methylolated hydroxyethyl carbamate or tetrakis (hydroxymethyl) phosphonium chloride, (c) applying thereto a fluorescent brightening agent, e.g. a pyrazoline, stilbene, coumarin or triazine type brightening agent, or (d) bleaching them with a reductive bleaching agent e.g. sodium hydrosulphite or sodium formaldehyde sulphoxylate. The steps may be carried out sequentially or simultaneously. The fibres may be treated by heating them in the treating solution at or near the boiling point of water and drying, padding them with the solution and heating them in air at a temperature near the boiling point of water and subsequently drying, or padding them with the solution and drying in an air oven at or near 80‹C for 5-10 minutes. The fibres may previously have been bleached with hydrogen peroxide which may contain sodium pyrophosphate. They may also be treated with a solution of a polyvalent metal cation, e.g. by soaking for ¢-1 hour in a 0.5% by weight aqueous solution of aluminium sulphate, treated with a shrinkproofing resin, e.g. a polyacrylate, or shrinkresist agent, e.g. a permanganate, permonosulphate or dichloroisocyanuric acid or a salt thereof, or dyed in pastel colours. When applying thiourea and formaldehyde or a source thereof separately, the thiourea is preferably applied first and at least the thiourea applied from a solution of dilute formic acid at pH 1-2.