洗濯による洗剤残留とその移染  [in Japanese] Mobility of Detergent Residue on Clothes to Contacting Substrates  [in Japanese]

It is known that a certain amounts of the detergents remain on the clothes even after rinsing out. The detergent residue on the clothes is gradually transfered to the substrates contacting directly with the cloth. This process should be one of the cause of skin irritation. In this paper, I described the relationship between the amounts of detergent residues on cotton clothes after rinsing and their mobility to cotton and silk clothes. The clothes were washed with the commercial detergents at the concentrations followed by the manifucture's suggested diluting guidelines, and then the washed clothes were rinsed with 30 times volume of water by the batch method. (1) After three times of rinsing, 1.5 mg detergent was still remained on 1 g of the cotton cloth. (2) Contacting with wet silk cloth, the detergent residue bound on the rinsed cotton cloth was transfered to the silk cloth linearly up to 1 hr and 11% of the residue was transfered to the wet silk cloth in 1 hr. When contacting with wet cotton cloth, 28% of the residue was transfered. (3) The higher detergent concentration for washing cause the more amount of residue and the more amounts of residue result the easier tranfer. (4) The mobility depend upon the moisture of the substrates to be transfered. These results show that it is hard to remove the detergents completely from washed clothes and a fair amount of detergent residue is easily transferable to the contacted substrates. From these results, it is suggest the possibility of the transfer of the detergent residue from underwears or diapers to skin. So, it could be recommended to wash the diapers for the babies with hypersensitivity using soaps in stead of synthetic detergents.