Cotton fabrics for the standard artificial soiling recommended by JOCS are used for the treatment under conventional industrial conditions. Their properties, however, are different markedly from lot to lot owing to the finishing conditions. Accordingly, authors investigated the quality change of the fabrics during oxidative bleaching by sodium hypochlolite solution. The change of copper number and average polymerization degree (fluidity), as well as the tensile and tear strength of bleached fabrics were determined.
Results obtained are as follows :
1) With the increases in copper number and/or fluidity of oxidized cellulose, the fabrics become to be easily soiled and the artificially soiled fabrics are easily desoiled as well.
2) Copper number and fluidity of oxidized cellulose are intimately related to the tear and tensile strength. Chemical damage of the fabrics caused by bleaching can also be detected from these measurements.
The authors found a clue to control the bleaching condition in order to supply standard cotton fabrics of constant properties.