Preparation method of dual-purpose hide for hair and leather by formaldehyde-free chrome-free tanning

Abstract

The invention discloses a preparation method of dual-purpose hide for hair and leather by formaldehyde-free chrome-free tanning. The method mainly comprises the following improved operation steps: degreasing: degreasing by using a mixed solution of sodium chloride, sodium carbonate, TS-80 degreaser and JA-50 degreaser; pickling: carrying out secondary pickling by using sodium chloride, HAC penetrant, formic acid, 535 acidic softening enzyme, sulfuric acid and TS-80 degreaser; and tanning and retanning: carrying out tanning and retanning by using a tanning agent containing an aluminum tanning agent and a tanning extract, a fatty aldehyde tanning agent is used for primary tanning before tanning, and no aluminum tanning agent or alum is used in the tanning and retanning process of the raw hide subjected to primary tanning. By using the formaldehyde-free chrome-free tanning process, the product is free of heavy metals or free formaldehyde; the degreasing procedure is reinforced, thereby avoiding using the dry washer; and the spreading process is used instead of the traditional bath tanning process in the tanning and retanning procedure, thereby saving abundant water and reducing the use of the tanning extract.

Description

Technical field [0001] The embodiment of the present invention relates to the field of wool leather processing. More specifically, the embodiment of the present invention relates to a method for preparing a formaldehyde-free and chrome-free tanned dual-purpose leather. Background technique [0002] The dual-purpose fur of wool and leather has been studied since the 1970s, but the technology is immature. Chrome tanning is mainly used, and the suede effect of the tanned leather is poor. Entering the 21st century, my country's tanning technology has made great progress, both in production technology and production equipment have been significantly improved, but the production process is still mainly chrome tanning, supplemented by other processes, or chrome tanning + aldehyde tanning (More), chrome tanning + tannin tanning (less), and it is mainly used for sheep skin, because the sheep skin is thicker and slightly softer, it is suitable for dual-purpose wool leather. The dual-use of...

AI Technical Summary

Problems solved by technology

However, due to its adhesion, the hair is yellowed, and because the molecular structure of Tara extract is relatively large, the absorption rate of skin board is relatively low, and the water-bath tanning method will use more Tara extract, which will cause waste and increase production costs. It is necessary to study a method to replace the water bath tanning method, so as to achieve the purpose of saving Tara extract and reducing costs

[0008] Formaldehyde is one of the important materials in the chemical industry. It has a wide range of uses. It is used in the processes of synthetic resin, leather, pesticide, fumigation and anticorrosion. From the perspective of histology, formaldehyde is a good fixer. It has the advantages of less tissue shrinkage, less damage, good preservation of inherent substances, uniform fixation, strong penetrating power, hardening of tissue and improving tissue elasticity. Therefore, formaldehyde has a good effect on tanning fur leather. However, formaldehyde has Toxicity, its harm to the human body mainly includes the following aspects: 1. Stimulation: Formaldehyde belongs to the protoplasm poisonous substance, which can combine with protein and has an irritating effect on the skin and mucous membranes. When inhaled at high concentrations, severe respiratory edema will occur, which directly affects breathing. 2. Fatal effect: direct skin contact with formaldehyde can cause allergic dermatitis, pigmentation, necrosis, and can induce bronchial asthma when inhaling high concentration of formaldehyde; 3. Mutagenic effect: high concentration formaldehyde is a genotoxic substance , animal experiments show that inhalation of high concentrations can cause nasopharyngeal tumors; 4. Typical consequences: headache, dizziness, fatigue, nausea, chest tightness, eye pain, palpitations, memory loss and autonomic disorders, etc. Long-term inhalation by pregnant women may cause fetal malformation or Stillbirth, long-term inhalation by men may lead to sperm deformity and death