The effect of fiber damage caused by repeated washing on the sebum yellowing

Abstract

With the growing awareness of sustainability among consumers, "reducing damage to clothing and extending its lifespan" has become one of the key objectives in laundry. Additionally, the proliferation of coin-operated laundromats and laundry services has led to increased use of large-capacity drum-type washing machines, which impose significant mechanical stress on clothing. Against this backdrop, we deemed it necessary to investigate the impact of large-capacity washing on fiber damage, particularly its influence on sebum yellowing, which is a contributing factor to clothing disposal.

In this report, we evaluated the relationship between the damage to appearance and physical properties of test cloth made of cotton, polyester, and nylon caused by repeated washing in a large-capacity washing machine (drum-type, 15 kg capacity) and the yellowing caused by model sebum components (squalene). The results revealed that in cotton cloth, an increase in washing cycles led to an expansion of fiber surface area due to fibrillation, which in turn increased reactivity with oxygen, thereby heightening squalene yellowing. On the other hand, in polyester and nylon cloth, the degree of yellowing decreased with an increase in the number of washes. Analysis utilizing sublimation transfer printing suggested that an increase in amorphous areas due to washing promotes the penetration of sebum components into synthetic fibers, thereby suppressing contact with oxygen and inhibiting squalene yellowing.