Discussion of the tanning technology without picking based on Zr-Al-Ti complex tanning agent

• 1、Xingye Leather Technology Co., Ltd., Jinjiang 362261, China
• 2、ational Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065, China

Abstract：The tanning teechnology without picking of cattle hide upper leather that carried out with Zr-Al-Ti complex tanning agent was studied. Different pre-tanning materials were first screened in the study, and then orthogonal experiment was designed, in which using the crust shrinkage temperature and COD content in waste tanning liquor as evaluation indexes, the effect of tanning agent dosage, basifying final pH, raising temperature and ratating time after adding liquor ratio on evaluation indexes was discussed. Results show that the following optimum conditions: pre-tanning with 2% phenolic syntan, the dosage of Zr-Al-Ti complex tanning agent is 30%, basifying final pH is 4.3-4.5, raising temperature to 45℃ and ratating time after adding liquor ratio is 3h, the shrinkage temperature of the wet-white leather can reach 87℃, the hand feeling is plump soft, and the tear strength is similar to chrome tanned leather. In addition, the contents of COD and chloride ion in waste tanning liquor are significantly decreased, especially chloride ion content is only 270 mg/L and significantly reduce the 65 times compared with the conventional chrome tanning.

Keywords： tanning without picking Zr-Al-Ti complex tanning agent phenolic syntan pre-tanning orthogonal experiment method