| 摘要 |
<p>Condensation products, suitable for plumping or filling tanned leather (see Group VIII), are made by reacting a water-soluble salt of sulphurous acid with a condensation product of dicyandiamide and formaldehyde, in aqueous solution and at a pH above 7, for a period of time adequate (in the absence of other substances) to cause the condensation product to become precipitable by water on dilution, and with a watersoluble salt of inorganic sulphonic acid and/or with a water-soluble salt of a sulphuric acid ester of an aliphatic alcohol containing at least 10 carbon atoms; the proportion of the salt of the sulphonic acid or the sulphuric acid ester being that required to cause the otherwise water-precipitable condensation to be non-precipitable p on dilution and the proportion of the sulphurous acid salt being from 0,010-,5 mol per mol of dicyandiamide. Condensation may be effected in the presence of a mono- or polyhydric alcohol or a mono- or poly-saccharide. The salts of sulphurous acid, sulphonic acid and esters of sulphuric acid may be added before, during or after the condensation of the dicyandiamide and the formaldehyde. The pH of above 7 may be maintained by the addition of sodium hydroxide or borax. Specified salts of sulphurous acid are the alkali metal and the ammonium sulphites, bisulphites and metabisulphites. Specified sulphonic acids (a) formaldehyde condensation products of naphthalene-, phenol- or naphtholsulphonic acids or the corresponding sulphomethylated compounds; (b) sulphonated or sulphoalkylated condensation products of formaldehyde with phenols, naphthols, naphthalene or xylene which condensation products may contain sulphite waste liquor, urea or melamine; or (c) betanaphthalene sulphonic acid, sulphonated p, p1-dihydroxy-diphenylsulphone or waste sulphite liquor; and (d) dyestuffs containing sulphonic acid groups. Specified sulphuric acid esters are octadecyl sulphonate sulphonated castor oil and sodium lauryl sulphate. Specified alcohols and saccharides are methyl-, ethyl- and isopropyl-alcohol; glycol, glycerol, sorbitol and 1 : 2 : 6-hexanetriol; and glucose, starch and molasses. Specification 772,440 is referred to.</p> |
