A Small-scale Washing Test That Reproduces the Mechanical Forces Occurring Inside a Commercial Washing Machine

Abstract

there are reports of testing the detergency performance of developed surfactants and microemulsions with a tergotometer 12−14) and examining the redeposition prevention effect of new polymers using a tergotometer 15) . There is also a proposal 16) for a test method using a tergotometer to estimate the amount of microfibers released from fabrics. Other studies have investigated the removal pesticides adhered to gloves using a launderometer 17) but a tergotometer is commonly used in studies focused on washing machines.A tergotometer has been used to study the interaction between temperature, pH, surfactant concentration, and agitation on laundry detergency as well 18−20) . However, when screening new synthetic substances or conducting detailed detergency tests on the compounding ratio and concentration effects of ingredients, a tergotometer is larger than desired. Therefore, a cleaning system that is smaller and can provide the same mechanical force is required.Therefore, in this study, a tube rotator, universal shaker, high-speed shaker, and magnetic stirrer were used to construct a system that can estimate the cleaning performance Abstract: A small-scale washing test model was proposed to reproduce the mechanical forces occurring inside a household washing machine in Japan. Washing tests were conducted using household washing machines, a tergotometer, and four types of small-scale washing test models using JIS-designated artificially soiled fabric. As a result of conducting washing tests in 10 households during winter and summer, we determined that the mechanical force of the washing machine was equivalent to 90-100 rpm agitation by a tergotometer. Similar detergency was obtained by rotating a 50 mL centrifuge tube with a tube rotator. Then, a centrifuge tube containing 35 mL of detergent solution, ten 1/4-inch stainless steel balls, and three 20 × 20 mm soiled fabrics was rotated at 50 rpm. Probability density functional theory analysis did not identify any kinetic problems, which means that the properties of the applied mechanical forces are similar to those occurring in the tergotometer and tube rotator test.