The method of tanning hides

 

(57) Abstract:

The inventive skin is treated with a solution of tannic composition with the following components concentration, g/l: chrome tanning agent in terms of Cr2O310; poly-2-oxypropylene chloride 0,005 - 0,01. table 2.

The invention relates to chemical treatment of skins, and tanned hides, and is intended for use in the leather industry for tanning skins from Astrakhan, sheepskin, goat and other skins.

There is a method of tanning skins using tanning composition on the basis of the reaction products of Polyoxymethylene with a secondary amine and alcohol, and after the reaction in the form of tertiary amino groups and ether groups [1].

There is a method of tanning skins using tanning composition on the basis of salts of trivalent chromium and a polycarboxylic acid, after reaction in the form of ether, urethane or amide [2].

Known methods of tanning skins have some drawbacks, namely the duration of the tanning process due to the absence in the structure of the active hydroxyl and ionogenic groups, as well as trudnodokazuemosti composition due to the formation of new substances in pria physico-mechanical characteristics of hides, skins, in the known method in the solution of the tanning composition on the basis of chrome tanning agent and a polymeric agent as a polymeric agent used polyhexamethylenediamine chloride with the concentration of the components in the following ratios, l:

Chrome tanning agent in terms of Cr2O310

Poly-2-oxoprop - Ammoni chloride 0,005-0,01

Introduction to tanning composition of the polymeric agent containing in its structure the active hydroxyl and ionogenic groups leads to the formation of khromosomnymi compounds a large number of cross-linking, "cross-linking" molecular chains of collagen. Tanning khromosomnymi compounds increases the speed of diffusion tanning particles of tanning solution and increases their content in the material, which leads to the reduction of the process time tanning and improvement of physical-mechanical characteristics of the skin.

P R I m e R 1. The polymeric agent is prepared as follows. In a three-neck flask pour 40,52 ml (0,595 mol) of 25% aqueous ammonia and with vigorous stirring to a solution of ammonia in small portions over 5-10 min add 25 ml (0,305 mol) of epichlorohydrin. The reaction mixture is heated to 80-90aboutC. After cooling is giving 1 h at 35aboutTo obtain product is a light brown color. Received the product a few times treated with acetone or isopropyl alcohol to remove unreacted substances. Yield, % 95 Content of chlorine % 26

Produced elm-

bone of 0.5% solution in water, DL/g 0,39; Exchange capacity of 0.1 n AgNO3, mg-equiv/g of 4,9;

Given viscosity in 0.1 KCl, DL/g 0,09

In the prepared chromic extract volume of 100 l containing 10 g/l of chromium (III) oxide at room temperature add a freshly prepared solution of poly-2-oxypropylene chloride containing 0.5 g of polymer. Intensively mix the components of the solution for 15 min and the process of tanning, which ends in 6 hours after the tanning process the samples processed according to the current plant technology and then the prepared samples are subjected to physical and mechanical tests. Check the end of the tanning process is carried out by sensing the temperature of the welding skins (PL.1).

Karakul skins have the following physical characteristics: tensile strength, EASC/mm20,96; elongation, %, 32.

P R I m m e R 2. In the prepared chromic extract volume of 100 l containing the example 1, containing 1 g of polymer, and the process of tanning samples Karakul skins, which ends after 6 hours the End of the tanning process and the subsequent processing is carried out as indicated in example 1.

Karakul skins have the following physical characteristics: tensile strength, kgf/mm2, 0,90; elongation, %, 29.

The study of the speed of penetration of the tanning agents into the tissue of the skin showed that in the known method the maximum value of the chromium oxide is reached after 12 h, when used in tanning solution polymer agent, in the proportions stated in the proposed method, the maximum value of the chromium oxide is achieved after 5 h, which indicates the acceleration of the process of tanning is more than 2 times due to the complexation of polymer chains oxide of chromium.

The results of physico-mechanical tests 25 samples Karakul skins subjected to the process of tanning on the proposed method are presented in table.2.

As can be seen from the above experiments, technical and economic efficiency of the invention is provided by the intensification of the process of tanning, improvement of physico-mechanical characteristics of the skin. P IS P> The METHOD of TANNING hides and SKINS by treating them with a solution of tannic structure on the basis of chrome tanning agent and a polymeric agent, characterized in that the polymeric agent is used poly-2-oxypropylene chloride with the following components concentration, g/l:

Chrome tanning agent in terms of Cr2O3- 10

Poly-2-oxypropylene chloride - 0,005 - 0,01

 

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