The Effect of Wash Temperature on Removal of Particulate and Oily Soil from Fabrics of Varying Fiber Content

Abstract

In the laundry process relatively high wash temperatures have traditionally been used for optimum soil removal. The use of lower wash temperatures could result in a substantial reduction in the amount of energy used in laundering. One of the purposes of this study was to determine soil removal at a range of wash temperatures with detergents of different formulations from cotton, polyester, and cotton/polyester fabrics. A second purpose was to evaluate the use of x-ray fluorescence analysis as a quantitative measure for determining particulate soil removal from fabrics. The samples were soiled by application of clay and either unlabeled or doubly-labeled synthetic sebum. Removal of oily soil was determined by measuring the radioactivity of the samples. Clay removal was measured by x-tay fluorescence analyses of iron and silicon, and overall soil removal was measured by changes in reflectance. Both clay and oily soil appeared to be best removed from cotton fabrics by higher wash temperatures. Low wash temperatures were best in removing the nonpolar fraction (triolein) of oily soil from polyester. Use of phosphate-built anionic detergents generally resulted in better soil removal than other types, regardless of wash temperature. Wash temperatures as low as 10°C gave acceptable soil-removal levels. Iron content varied with clay-particle size, thus silicon was the preferred indicator of clay content of fabrics.