Method of preparing protein polypeptide retanning agent

Abstract

The invention provides a method for preparing a protein polypeptide re-tanning agent. The method comprises the following steps: chrome leather waste is placed into an aqueous solution dissolved with calcium lignosulphonate and sodium hydroxide, subjected to hydrolysis reaction at a temperature of between 100 and 110 DEG C, and subjected to temperature reduction after hydrolysis reaction; and the pH value of the mixture is adjusted to between 6.5 and 7.5, and the protein polypeptide re-tanning agent is obtained, wherein the mass ratio of the chrome leather waste to the calcium lignosulphonate to the sodium hydroxide is 3.5-4.0 to 1.6-1.9 to 1. The method has the advantages that the adequate hydrolysis technology is adopted, and products obtained by hydrolysis of collagen are more stable and more simple and convenient to use, and are difficult to delaminate; and due to addition of the calcium lignosulphonate, the method is favorable for dispersing the chrome leather waste into a sodium hydroxide aqueous solution, promoting hydrolysis of the chrome leather waste, making the hydrolysis reaction tend to be consistent, causing the molecular weight of hydrolysis products to be controlledwithin a small range between 5,000 and 10,000, realizing uniform hydrolysis of the collagen of the chrome leather waste, and making the final products stable, difficult to delaminate and having better re-tanning function.

Description

(1) Technical field [0001] The invention relates to a preparation method of an environmentally friendly novel protein polypeptide retanning agent. (2) Background technology [0002] The leather industry is a pillar industry in my country's light industry. In recent years, with the rapid development of the leather and shoe-making industries, it has become a major leather-making country in the world and one of the most active and promising markets for leather trade. [0003] Although my country's leather chemical materials are developing rapidly, there are many low-level repetitions, few innovations or high-level ones, unstable quality, weak corporate innovation capabilities, and low manufacturing process levels. Compared with countries, there are obvious gaps such as poor quality, poor brand and price difference, so in-depth research on the combination mechanism of various leather chemicals and leather collagen fibers, and various mechanical properties, thermodynamic properti...

AI Technical Summary

Problems solved by technology

[0006] Chinese patent CN200710030087.7 ​​provides a method for preparing a protein polypeptide retanning agent from chrome leather waste. It uses ammonium lignosulfonate as a modifier and undergoes hydrolysis at room temperature to obtain a hydrolyzate. Due to the low temperature, the Insufficient hydrolysis results in large molecular weight of protein and polypeptide, and its molecular weight is in the range of 30,000 to 40,000. The large molecular weight of protein and polypeptide is difficult to fill into the cortex, and the retanning effect is not ideal.

The molecular weight of the protein polypeptide prepared by this patent method is about 5,000 to 10,000, which is suitable for retanning requirements and can achieve the best retanning effect; if the molecular weight is lower than 5,000, the protein polypeptide can be easily filled into the cortex Medium, resulting in hardened cortex after retanning and poor hand feeling