A kind of preparation method of hydrolysis-resistant foamed bovine split leather

Abstract

The invention discloses a method for producing hydrolysis-resisting cattle hide split leather through a direct foaming technology. The method is characterized in that by means of pretreatment of positive ion polyurethane, a cattle hide split leather blank has higher interlaminar peeling strength, an adopted hydrolysis-resisting water-base polyurethane foaming coating is provided with a foam structure, thus, the influence on the air and water vapor permeability performance of natural leather is little, meanwhile, the leather body softness degree and the surface fine degree of the split leathercan be provided, and the hydrolysis-resisting foamed cattle hide split leather with the performance rivaling that of natural top-layer leather is obtained. The method can be adopted for replacing a traditional transferring coating method, expensive release paper resources are saved, the method can also replace a traditional wet method (solidifying method) based on solvent polyurethane, and pollution of an organic solvent is eliminated. The method can be widely used for manufacturing the cattle hide split leather, the quality and the additional value of cattle hide split leather products are improved, and the method is wide in application prospect.

Description

technical field [0001] The invention belongs to the field of leather manufacturing, in particular to a method for preparing hydrolysis-resistant foamed bovine split leather. Background technique [0002] Natural cowhide is generally thick and can be split into two or more layers. The top layer of leather is mostly used for the processing of high-grade natural leather products. Not as practical as the top layer of leather, but the second layer of leather is still natural leather, a natural hygroscopic and dimensionally stable genuine leather material. [0003] There are two traditional production methods for cow split leather. The first method is to grind the surface first, then spray the bottom layer, knead the middle layer, and finally emboss and soften it, and then spray the top layer. This production system has a thick coating and lacks bubble feeling and Resilience, poor air and moisture permeability, low production efficiency, and high cost; the second method is called...

AI Technical Summary

Problems solved by technology

[0003] There are two traditional production methods for cow split leather. The first method is to grind the surface first, then spray the bottom layer, knead the middle layer, and finally emboss and soften it, and then spray the top layer. This production system has a thick coating and lacks bubble feeling and Resilience, poor air and moisture permeability, low production efficiency, and high cost; the second method is called the transfer coating method, which is to first coat the polyurethane on the release paper, and then use the dry transfer coating technology to bond the polyurethane film On the surface of the ground split leather blank, the split leather with the surface similar to head leather is processed, also known as "two-layer transfer film leather". The cow split leather made by this method has poor hygiene performance (here generally refers to breathable and moisture-permeable leather). Poor) and feel hard; in addition, the release paper is expensive, the price is as high as 50 yuan / square meter, which seriously pushes up the production cost

[0004] In order to improve its breathability and moisture permeability, the wet coagulation process is favored by people. The production process is to grind the surface first, then coat the surface of the leather with solvent-based polyurethane, and then place it in about 18% dimethylformamide. Wet coagulation in (DMF) aqueous solution, after washing and drying, solvent-based polyurethane is used to coat the surface layer. The cow split leather produced by this production method has good foam feeling and resilience, and excellent hygienic performance. It is a large amount of waste water and waste gas containing DMF, which causes environmental pollution. At the same time, the residue of DMF solvent in the product will encounter trade barriers, which restricts the product from entering the high-end market. The foam coating is not firmly bonded to the leather base, and the peeling strength is not high

Images