GB566810A - Method of and preparations for improving the whiteness of materials - Google Patents

Abstract

A process for improving the whiteness of materials such as paper, textiles, starch or sugar, comprises treatment with a small proportion of a blue-fluorescent substance in admixture with a blueing agent. Specified fluorescent substances are hydroxy coumarins, e.g. umbelliferone or b -methyl-umbelliferone, 1-naphthylamine-4-sulphonic acid and sodium 2 - naphthylamine - 6 : 8 disulphonate and specified blueing agents are the customarily used ultramarine, indigo and alizarin dyestuffs. Materials such as textile yarns or fabrics or paper are advantageously treated with such a mixture applied in slightly alkaline aqueous solution in an amount corresponding to about 0.001 to 0.1 per cent of the blue-fluorescent substance per weight of the material to be treated. In an example, new white cotton fabrics are washed with soap ten times, rinsing three times in clean water after each wash, dried, ironed, rinsed in an aqueous blueing solution slightly alkaline, e.g. with borax or sodium carbonate containing 0.01 per cent of beta-methyl-umbelliferone and 0.004 per cent ultramarine, dried and ironed. Specification 522,672 is referred to.ALSO:A process for improving the whiteness of materials such as paper, textiles, starch or sugar, comprises treatment with a small proportion of a blue fluorescent substance in admixture with a blueing agent. Specified fluorescent substances are hydroxy coumarins, e.g. umbelliferone or b -methyl-umbelliferone, 1-naphthylamine-4-sulphonic acid and sodium 2 - naphthylamine - 6:8 - disulphonate and specified blueing agents are the customarily used ultramarine, indigo and alizarin dyestuffs. Materials such as textile yarns or fabrics or paper are advantageously treated with such a mixture applied in slightly alkaline aqueous solution in an amount corresponding to about 0.001 to 0.1 per cent of the blue-fluorescent substance per weight of the material to be treated. In an example, new white cotton fabrics are washed with soap ten times, rinsing three times in clean water after each wash, dried, ironed, rinsed in an aqueous blueing solution slightly alkaline, e.g. with borax or sodium carbonate containing 0.01 per cent of beta-methyl-umbelliferone and 0.004 per cent ultramarine dried and ironed. Specification 522,672, [Group VIII], is referred to.ALSO:A process for improving the whiteness of sugar comprises treatment with a small proportion of a blue - fluorescent substance in admixture with a blueing agent. Specified fluorescent substances are hydroxy coumarins, e.g. umbelliferone or b -methyl-umbelliferone, 1-naphthylamine-4-sulphonic acid and sodium 2 - naphthylamine - 6 : 8 disulphonate and specified blueing agents are the customarily used ultramine, indigo and alizarin dyestuffs. Specification 522,672 is referred to.