Low-dosage DCCA-Protease Process For Wool Anti-Felting Finishing

In order to reduce the influence of DCCA on the environment of the existing anti - felting process of DCCA-protease, a DCCA-protease process of pretreatmenting with low-dosage DCCA is selected firstly [ Modified process: the concentration of DCCA is 1% (o.w.f), protease is 2.5% (o.w.f) ]. And after the process, MTG is used for a strengh repairing for the wool to lower the damage caused by the modified DCCA-protease process.Through comparting the properties of wool treated with current high DCCA - low protease process [ the concentration of DCCA is 3.5% (o.w.f), protease is 2.5% (o.w.f) ] and modified low DCCA - high protease process, it was found that though the shrinkage of wool treated with the modified treatment is slightly higher than that of current process, but it is already got the requirement of "machine washable". Further more, the modified treatment is better in holding the strength of wool. After the process of the modifided one, the strength loss is 27.23%, much better than the current one of 36.47%. The two different processes cause different changes to the wool, such as the wettability of wool, whiteness, dye ability, style and so on.By comparing the properties of wool before and after the MTG to the modified DCCA - protease process, it was studied that the breaking strength of single wool fabric is significantly increased with the dosage of MTG. When the concentration of MTG is 6% (o.w.f), the strength loss is dropped from 27.23% to 18.15%. In addition, properties such as wettability, whiteness, dye ability, style are also influenced by MTG.The mechanism of modifided DCCA - protease for anti - felting and MTG for strenghening were studied through the speed of protein reduction, the weight loss, amino acid analysis, scanning electron microscopy and the analysis of FTIR. The results showed that low concentration DCCA [ 1% (o.w.f) ] also has strong modification effect to the surface of wool. Pretreatment with low concentration of DCCA can significantly improve the speed of protein dissolving caused by protease, and reduction rate is high. Amino acid analysis shows the same result. The results of SEM show that the scales on the surface of wool have been stripped depleted by the DCCA - protease process of low concentration DCCA. FTIR shows that pretreatment of DCCA oxidized the cystine disulfide to cysteine sulfonate and cysteic acid. And the cross-linking of MTG can change the secondary structure of keratin.