RU1818351C - Process for preparation protein tanning liquor for natural leather - Google Patents

Abstract

SUMMARY OF THE INVENTION: leather chips are treated with a solution of sulfuric acid in ten stages, and in the first stage, processing is carried out in the following ratio, wt.%: Leather chips 9.5-10.5; water 8.5-9.3; sulfuric acid 9.6-10.8, and at each subsequent stage the remaining chips are added to the mixture in equal portions up to 100 wt.%, after which a 25% solution of ammonium hydroxide is introduced into the homogeneous mass to a pH of 3.2- 3.7. 2 tab.

Description

The invention relates to light industry and can be used in the process of processing leather chips for using the resulting product as a tanning and filling reagent for producing leathers for upper and lower shoes. The aim of the invention is to simplify the process while improving the quality of the filler.

This is achieved in that the treatment of leather chips with a sulfuric acid solution is carried out in ten stages, wherein, in the first stage, chips, water and a sulfuric acid solution with a density of 1.84 g / cm3 are mixed in the following ratio, wt.%: Leather chips 9, 5-10.5 Water 8.5-9.3 Sulfuric acid 9.6-10.8, and at each subsequent stage, the remaining chips are added in equal portions to 100 wt.%, After which 25 are added to the homogeneous mass % solution of ammonium hydroxide to pH 3.2-3.7.

A significant difference of the proposed technical solution is the preparation of the product without any additional processing and its use as a blowing and selective-filling reagent. The claimed method is simpler and cheaper than described in the prototype. In addition, the selected mode of processing leather chips allows to obtain a product with a sufficiently high concentration of tanning chromium compounds.

The method is carried out as follows.

1 kg of chips with a moisture content of 40%, obtained by planing a tanned semi-finished product intended for the production of leather for upper shoes, 8.5-9.3 liters of water and a solution of sulfuric acid with a density of 1.84 g / cm3 in the amount of are loaded into a container of thermal insulation material 9.6-10.8 kg; stirred and allowed to stand for 15 minutes. After that, with an interval of 15 minutes with periodic stirring in a container equal to portions00

ate

ABOUT

in nine steps, load the rest of the chips. After the chips are completely dissolved, a 25% solution of ammonium hydroxide is introduced into the container to a pH of 3.2-3.7.

Table 1 shows examples of the method at the optimal ratios of the parameters of the chip dissolution process. Table 2 shows some of the properties of the obtained protein filler, which has tanning properties, as well as the properties of the leather semi-finished product treated with this product under the following conditions: the processing object is pickled goblet from the mill, the process parameters are 39.6% by weight of the product ; LCD 0.7; temperature 18-20 ° C; duration 2 hours

As can be seen from the tables (Examples 1-3), the amount of chips dissolved in the first stage equal to 9.5-10.5% is optimal. This is due to the fact that an increase in the fraction of chips in the first stage while maintaining the flow of water and acid will lead to a noticeable slowdown in the dissolution of chips in this stage due to the uneven distribution of acid in the mass of not completely flooded chips. To increase the flow of water and acid is impractical, because this will lead to a decrease in the mass fraction of tanning chromium compounds in the product and to additional material costs for sulfuric acid and ammonium hydroxide. Reducing the amount of soluble chips in the first stage of dissolution will increase the processing time in subsequent stages or increase their number.

Conducting the dissolution of leather chips in ten stages is caused, on the one hand, by the condition of obtaining a product with a maximum content of tanning chromium compounds, and, on the other hand, by the desire to achieve a minimum duration of the chip dissolution process.

The implementation of the proposed method allows to obtain a product from leather chips with a filling and tanning effect. In addition to increasing the weld temperature of the salt by 17-18 ° C, the treatment of the product with the product helps to obtain a semi-finished product with a uniform

its thickness and density in topographic sections. This in turn will have a positive effect on the output of the finished product area.

The use of the proposed method for producing a protein filler with tanning properties provides the following advantages in comparison with existing methods;

saving reagents introduced into the dermis

for filling and retanning of the leather semi-finished product. The expected economic effect will be 17.65 p. per 100 m of leather for upper shoes from cattle hides,

improving the quality of finished products by improving the hygienic properties of the skin, its grinding ability, adhesion of the coating to the skin, reducing perfume,

obtaining leather with uniform density and thickness, uniform coloring along topographic areas (during drum dyeing), reducing the consumption of raw materials, reducing the consumption of tanning compounds

chromium in the production of kodi, reducing the amount of unsold waste, which is an additional source of the environment.

FORMULA AND SECTION

A method of obtaining a protein filler with tanning properties for natural leathers, comprising treating the leather chips with a solution of sulfuric acid with a density of 1.84 g / cm until a homogeneous

mass, characterized in that, in order to simplify the method while improving the quality of the filler, the treatment of leather chips with a solution of sulfuric acid is carried out in ten stages, and

in the first stage, chips, water and a solution of sulfuric acid are mixed in the following ratio, wt.%:

Tannery shavings 9.5-10.5 Water 8.5-9.3

Sulfuric acid 9.6-10.8.

and at each subsequent stage, the remaining chips are added to the mixture in equal portions up to 100 wt.%, after which a 25% solution of ammonium hydroxide is introduced into the homogeneous mass to a pH of 3.2-3.7.

Table 1

table 2