抄録
The rate of removal of fatty soils from polyester and cellulose fabrics was studied by means of a radioactive-tracer technique in an attempt to find out the cause which decreases a whiteness of polyester fabrics during progressive washings.
Six redioactive typical fatty compounds such as stearic acid-l-C14, oleic acid-l-C14, tristearin-l-C14, stearyl alcohol-1-C14, cholesterol-4-C14, and octadecane-1-C14 were chosen from those obtained through Brown's chemical analysis of soils contained in those worn clothings.
Small samples of polyester and cellulose fabrics were soaked in the respective benzene solutions of C14 labeled compounds described above, dried at room temperature to evaporate the solvent, then washed at 50°C with the aqueous detergent solution at different times and dried.
Radioactivities of washed and unwashed fabric samples were then measured by means of Geiger-Müller end window counter. Thus, having corrected for the background count, the ratio of the count of the washed sample to that of the unwashed sample provids a measure of the proportion of the labeled fatty compound retaining on the sample.
By a contact method autoradiographs have also been made of several kinds of samples which were washed for 20 times after soiling.
The results obtained are as follows: (i) Soils on polyester fabrics are more difficult to be removed than those on cellulose fabrics. (ii) The rate of removal considerably differs with the types of fatty soils. Namely the rate increases in the order: tristearin stearyl alcohol cholesterol stearic acid oleic acid octadecane
