GB596405A - Improvements in the washing of textiles and in detergents therefor - Google Patents

Abstract

White textile materials are washed in an aqueous bath containing a detergent and a very small proportion of a substantive blue-fluorescent compound which is a derivative of a di - aminobenzoyl - amino - stilbene sulphonic acid formed by the substitution of one of the hydrogen atoms in each of the -NH2 radicals attached to the terminal rings by an organic radical which does not contain an -NH2 radical directly attached to an aromatic nucleus and which would not itself render the substituted compound formed unstable to light and oxygen, and which does not itself possess any tinctorial properties. Advantageously, the aqueous bath contains not more than 0.05 per cent of the blue-fluorescent compound, and suitably between 0.01 and 0.001 per cent, calculated on the weight of the materials. Specified compounds are: derivatives of a di-aminobenzoylamino-stilbene sulphonic acid formed by the substitution of at least one of the hydrogen atoms in each of the amino radicals attached to the terminal rings by an organic radical which does not contain an amino radical directly attached to an aromatic nucleus, which would not itself render the substituted compound formed unstable to light and oxygen, and which is of a non-chromogenic nature, e.g. methyl, benzoyl or acetyl, as in the following: 4 : 41 - di - p - methylaminobenzoyl - amino-stilbene-2 : 21-disulphonic acid 4 : 41-di-p - benzoylaminobenzoylamino - stilbene - 2 : 21 - disulphonic acid, 4 : 41 - di - p - acetylamino - benzoylamino - stilbene - 2 : 21 - disulphonic acid and the corresponding m- or o-compounds; 4 : 41-di-p-ureidobenzoylamino-stilbene-2 : 21-disulphonic acid or salts of these acids. In an example, a wash liquor containing about 0.4 per cent of soap product consisting of ordinary soap in which is incorporated proportions ranging from about 0.003 to 0.06 per cent of 4 : 41-di-p-acetylaminobenzoylamino-stilbene-2 : 21-disulphonic acid is used to wash white cotton and linen material either at about 40 DEG C. or at the boil. A detergent contains a small proportion of the order defined, of a substantive blue-fluorescent compound of the kind specified. Specified compounds are the acids named above and their salts which are advantageously incorporated in the detergent in a proportion of less than 1.0 per cent by weight, and suitably between 0.001 and 0.1 per cent. Soapy and non-soapy detergents are specified. The Provisional Specification describes also a modification of the invention in which the blue-fluorescent compounds are added to a pre-soaking or "break" solution instead of to the actual detergent solution. Specifications 522,672, 584,436 and 584,484 are referred to.