Copper Chelants and Antioxidants in Laundry Detergent Formulations Reduce Formation of Malodor Molecules on Fabrics

Abstract

For consumers who use laundry detergents, a top unmet need is to reduce malodor that can persist on fabrics, even after washing and drying. A known source of odor is autoxidation of residual sebum on fabric, leading to the generation of an array of odiferous compounds. To prevent this oxidation process, two technologies were evaluated: (i) antioxidants to scavenge radicals and (ii) metal chelants to inhibit the involvement of copper ions as catalysts in the autoxidation process. Copper is a common component of sweat, soil, and municipal water supplies, especially where copper piping is involved, which is typical in many US homes and businesses. For the evaluations, swatches of fabric were treated with artificial sebum, then washed in commercial washing machines with tap water containing laundry detergent, and dried using commercial dryers. Copper added to the wash at a level representative of consumer homes substantially increased the formation of known malodor molecules. Copper chelants [in particular, diethylenetriamine (DETA)] added to the wash were effective in inhibiting the formation of malodor molecules. In combination with antioxidants [in particular, methyl 3-(3, 5-di-tert-butyl-4-hydroxyphenyl)propanoate (MtBHPP)], the inhibitory effect was greater. Even at low concentrations (<1%), DETA and MtBHPP were effective at inhibiting the generation of known malodor molecules on fabrics. As DETA and MtBHPP meet performance, cost, and stability considerations, they hold promise for use in high-quality commercial laundry detergent products designed to eliminate malodor on consumer fabrics.