Washing wool with surfactants and a non-toxic solvent microemulsion: influence of water hardness

Abstract

In this work, detersive power (soil removal) was studied after washing a soiled wool fabric with addition of a non-toxic solvent microemulsion to conventional washing detergent formulations with the aim of improving the performance of the conventional washing. The non-toxic solvent used was dimethyl sulfoxide micro-dispersed with an amphoteric surfactant as emulsifier. The fabric was washed with biodegradable non-ionic surfactants such as an alcohol ethoxylate (AE) with 7 mE.O. and an alkyl polyglucoside with 1.4 glucoside groups (APG). The fabric used was EMPA 107 wool (soiled with standard impurities). The non-ionic surfactants were used separately and in mixture in varying proportions for the washes. Given the large amount of impurities in the wool fabric, sodium carbonate and sodium chloride were used to attain a suitable pH to avoid damaging the wool. The fabric was washed at low temperature with water of different hardness (20º hf, 30º hf and 40º hf). In addition, the sequestering agent DTPMP was used to obtain an improvement of detersive power at the hardness of 40º hf