Soil Remaining on Fabrics after Laundering as Evaluated by Response Surface Methodology

Abstract

Response surface methodology was used to visualize the interactive effects of detergent concentration, agitation time, and wash temperature on removal of soil from fabrics. Plots of the whiteness index of fabrics after repeated soiling and laundering indicated that maximum whiteness occurred at approximately 0.20% detergent concentration. The wash temperature required for maximum whiteness varied with fabric type. Changes in length of agitation time within the limits of the study had a minor effect on soil removal. Labeled components of synthetic sebum could be completely removed from acrylic and nylon fabrics. Both polar and nonpolar components became trapped in the cotton fibers. Removal of nonpolar triolein from polyester was incomplete and decreased as wash temperature increased. Particulate soil, as measured by x-ray fluorescence of silicon, could be completely removed from all fabrics except the acrylic.Detergent concentration, wash temperature, and agitation time are variables that are easily controlled in the home laundering process and are known to affect soil removal from fabrics. Because each of these variables or factors influences molecular activity within the wash system, one expects the response function for one factor is not independent of the levels of the other factors. Most soil removal studies to date have looked at the effects of varying only one factor at a time; however, when factors are interrelated, using response surface methodology provides a more accurate picture than varying factors independently.In this study we examined and described the combined effects of detergent concentration, agitation time, and wash temperature on soil removal from four fabrics of different fiber types. We used multiple regression analyses and computer plotting capabilities to determine and visualize the relative importance of the factors and the combinations of factors providing optimum soil removal. We measured soil remaining on the fabrics after laundering in a general manner by determining the fabric whiteness. We obtained information on specific components of the soil remaining using radioactive labeling and x-ray fluorescence techniques. experimental DESIGN A central composite second order rotatable design with three variables was used for this experiment [2].

Response Surface Methodology

“…tainment volume, radiation heat transfer coefficient, and sodium oxide fraction on fraction leakage. Prato and Morris (1984) studied the effect of detergent concentration, agtation time, and washing time on the amount of soil removed Erou, fabric. In order to underscore the natural application of RSM and second order composite designs in human factors engineering type experiments, Simon (1970) illustrates with a study involving three display panel-type variables and their effect on target recognition for airline pilots.…”

Optimisation of Detergent Ingredients for Stain Removal Using Statistical Modelling

“…Since it is not possible to examine all variables simultaneously in a single test, detergency tests are designed to evaluate a limited number of variables. The main challenge of detergency evaluation is to define meaningful test conditions and develop procedures representing natural soiling and practical washing conditions [3].…”