Effects Of Different Pretreatment On Shrink-Resistance And Other Properties Of Wool With Protease Finishing

Being of gentle working condition, high efficiency and environmental protection, enzyme has been widely used as biologic catalyzer in textile industry, However, the complicated structure and the compact cuticle of wool make it different for solo protease treatment to exert a good effect. Therefore, pretreatment such as oxidation or reduction is necessary.Shrinkage, Weight loss, dyeing properties, wettability, whiteness, fabric style, anti-fuzzing and pilling characteristics as well as micro analysis such as Allworden reaction, SEM, infrared spectrum analysis were all accessed to compare the different effects of oxidation and chlorination on the following protease's hydrolyzation .It shows that compound finishing of H₂O₂ followed by protease confers obvious weight loss but no improvement in shrink-resistance. However, samples treated by compound finishing of DCCA followed by protease obtain both obvious weight loss and notable shrink-resistance. Comparison of the two different finishing flows indicates that DCCA confers better effect on wool's shrink-resistance.The two different pretreatments have brought great influence on other performances of samples treated by protease. The dye-uptaking of samples treated by DCCA and protease remains stable, but K/S increase to certain degree. While for the samples treated by H₂O₂ and protease, such two dyeing properties both decrease a bit.Comparing with samples treated by solo protease, wool color change of sample treated by H₂O₂ and protease has decreased more. As for samples treated by DCCA and protease, color remains the same as that of solo protease finishing. What's more, DCCA confers good anti- pilling than H₂O₂ does. The only advantage of H₂O₂ pretreatment is the whiteness of sample has been improved more than that of DCCA. SEM, Allworden and the result of wettability show the compact scale hasn't been destroyed by compound finishing of H₂O₂ followed by protease. Contrarily, wool fiber treated by compound finishing of DCCA and protease has became rather smooth, whose scale has been peeled obviously. Analysis of fabric style also proves that DCCA could further reduce wool's surface roughness, which has been reduced to certain degree by solo protease finishing. In contrast, roughness of samples treated by H₂O₂ pretreatment increased a little. Infrared spectrum analysis indicates that, comparing with H₂O₂, more disulfide bonds of cystine can be oxidized to cysteine sulfonate and cysteic acid by DCCA, thus providing more reaction sites for protease hydrolyzation. Therefore, the effect of protease can extend well in large area on the wool surface but limit in depth after DCCA finishing, while it is just the reverse after H₂O₂ finishing.