Patent ID: 6398820
Filing Date: 2002-06-04
Classification: C11D

Abstract:
A process for washing laundry comprising:1) forming a wash liquor comprising: (A) a washing alkali component comprising: (A1) an anionic surfactant and a water-soluble silicate; (A2) an alkali metal hydroxide and a complexing agent; or (A3) the anionic surfactant and water-soluble silicate of (A1) and an alkali metal hydroxide, a complexing agent, or a mixture of an alkali metal hydroxide and a complexing agent; and (B) a surfactant component comprising a nonionic surfactant selected from the group consisting of C8-18 fatty alcohol alkoxylates containing at least 5 alkoxy groups, C8-18 fatty alcohol ethoxylates containing at least 7 ethoxy groups, C8-18 fatty alcohol ethoxylate/propoxylates containing at least 4 ethoxy groups and at least 2 propoxy groups in the molecule, and mixtures thereof; 2) contacting said wash liquor with laundry in a standard washing machine for institutional laundries; and 3) treating wastewater containing the wash liquor after laundry contact by membrane filtration, wherein the throughflow rate is reduced by less than 10 percent over an operating time of 120 hours.