A METHOD OF DRY CLEANING ARTICLES USING DENSIFIED CARBON DIOXIDE

摘要

The present invention provides a method for the removal of stains from articles, especially fabric, using densified carbon dioxide. More particularly the invention is concerned with a method of dry cleaning an article comprising the successive steps of (a) contacting the article with a fluid dry cleaning composition containing densified carbon dioxide at a temperature between -20 and 60 ~C and a pressure between 1 and 100 MPa, so as to allow stains to dissolve and/or to disperse into the fluid dry cleaning composition and (b) separating the article and the fluid dry cleaning composition; wherein the fluid dry cleaning composition comprises an ionic surfactant in a concentration of between 0.01 and 15% by weight of the carbon dioxide and wherein during step a) at least 10%, preferably at least 30% of said ionic surfactant is present in an undissolved solid form. It was surprisingly discovered that the use of an ionic surfactant, e.g. a surfactant that contains a lipophilic alkyl residue and an amine, sulphate, phosphate and/or carboxylate residue, produces exceptionally good cleaning results if said surfactant is employed in an amount that exceeds its maximum solubility in the densified carbon dioxide composition and provided said surfactant is present during the cleaning operation in the form of undissolved solid particles.