High pH value fast leather tanning method

Abstract

The invention discloses a high pH value fast leather tanning method. The high pH value fast leather tanning method mainly comprises the following steps: pre-treating bare leather, penetrating by using chrome tanning agent, extracting alkali and the like. Organic acids and salts of organic acid are used in the pre-treating step of the bare leather to reduce pH value of the bare leather around the isoelectric point so as to form effective masking, or organic acids and salts of organic acid are used to reduce pH value of the bare leather to 6+ / -0.2 and 0.4-0.6wt% masking agent is added to the bare leather to form effective masking. In the chrome tanning step, positive chrome ions in the chrome tanning agent combine with peptide chain carboxyl ions R-COO- to form coordinate bonds to complete leather tanning. The high pH value fast leather tanning method provided in the invention has advantages such as short tanning time, is free of traditional acid etching process, and has small discharge of waste water with high chloride ion content, high use ratio of chrome tanning agent, high quality of finished leather and the like.

Description

technical field [0001] The present invention relates to a kind of leather tanning method, more specifically relate to a kind of high pH value fast leather tanning method. Background technique [0002] The traditional tanning production process uses water as the medium to process raw hides into finished leather through chemical, physical and mechanical actions. The chemical treatment process of leather production is carried out in a wide pH range, such as: soaking, liming, deliming, softening, pickling, tanning, neutralization, etc., repeated liming, deliming, pickling In the process of processing, alkali extraction, etc., the repeated action of acid, alkali and salt makes the content of salt in tannery wastewater very high; at the same time, the repeated action of acid, alkali and salt also causes the cortex to be damaged to varying degrees. [0003] In the above process, pickling is an indispensable process for the leather tanning process. The main purposes of the traditio...

AI Technical Summary

Problems solved by technology

[0008] It can be seen from the above that the pickling process is very critical for smooth and high-quality tanning of bare hides. However, in the pickling process, the acid swelling of the pickling is suppressed due to the use of 5-8 wt% sodium chloride of the skin weight ( acid swelling), the use of a large amount of salt, on the one hand, caused the dehydration of the bare hide, making the finished leather flat and not plump; The acid-soluble protein and salt-soluble protein in the bare hide enter the water body during the acid process, which will also increase the COD and BOD pollution load in the wastewater

[0009] In addition, in the traditional leather tanning process, the pickling and tanning process usually takes at least 20 hours, and the working hours are long and the process is complicated