Abstract
Formulations of compact and supercompact heavy-duty detergents, which are being used widely around the world, differ from those of conventional heavy-duty detergents. Significant differences in composition exist between the compact detergents and the conventional detergents. The compact detergents have a higher content of surfactants, oxygen bleach and enzymes than the conventional detergents. We have studied to find the most effective washing conditions of artificially soiled cloths with a commercial, supercompact, heavy-duty detergent and a drum type washing machine which is becoming the preferred type in Korea. Moreover, we have studied the washing performance with an impeller type washing machine, which has heretofore been the most popular type in East Asia. With the drum-type washing machine, washing performances improved as the washing temperatures went up and the washing times were lengthened. Though the rate of soil removal with a double recommended dosage was higher than with the recommended amount at $20^{\circ}C$, the effects of the higher dosage decreased as the washing temperatures increased. Finally, the washing performances with the two different dosages were the same at $60^{\circ}C$. The washing performances at $40^{\circ}C$ with the recommended dosage for 90 minutes were the same as with the double recommended dosage for 45 minutes. The soil removal efficiencies with the impeller-type washing machine were much lower than those of the drum-type washing machine. The reasons for this were the higher bath ratio that led to the lower concentration of wash liquor, the shorter washing time, and the lower washing temperature.