SU48993A1 - The method of tanning cheese fine leather or fur - Google Patents

Description

The old way of tanning with tee cheese, as well as furs by treating geels and skins with bread kvass, is incompatible with modern tasks, industrialization and chemicalization of the leather industry. As is known, the active principle in bread kvass are organic acids formed during the fermentation of carbohydrates, and the addition of table salt has the purpose, in addition to its preservative action, to prevent the skin from swelling (the so-called major) from the action of acids. In such juices, complex enzymatic and bacterial processes take place, and often putrefactive, causing damage to the skin. Accurate control of all these processes is almost impossible. It is not necessary to say that flour, as a foodstuff, is absolutely inexpedient to use for technical purposes.

When the active principle of bread kvass was clarified, they began to use a direct treatment with acid and table salt, which was called pickling, usually using hydrochloric or sulfuric acid, to replace the ferment. This method began to be used in fur and sheepskin and fur production and

pei / is recommended only for non-responsible raw materials. A major disadvantage of this pickling process is that the acid comes in close contact with the leather tissue, so that complete washing of the acid does not seem to be possible. A sufficiently large amount of free mineral acid remaining in the skin cannot but reflect adversely on the strength of the skin or fur, especially during long-term storage, since such an adverse effect is well-known and provided for by the Voivod standards which allow sulfuric acid in the amount of not more than 0 ,four%. As is known, pickling is also used as a preparatory operation for tanning, with the aim of separating leather fibers to their dehydration for the free penetration of tannins. But here, too, the presence of free mineral acid, which precipitates tannin, and the like, is also a significant drawback. The proposed method, which has all the advantages of the bread and pickle methods, but is devoid of their disadvantages, aims at obtaining the raw material by treating the salt with alkali metal mineral salts without using the free acid. These salts can be neutral or acidic, both strong and weak acids, and strong and weak bases of KASO., NagCO, (NH,), SO ,, NaHSO., NaC, NagSaO ;; Other.

If, after the usual soaking-up operations, the cheddis is subjected to the action of a solution of any of the indicated salts of a corresponding concentration, then after drying such a scum loses its goviform parchment appearance. The fibers are disconnected and not glued. The skin has a pleasant white color, is full and to a much greater degree approaches the real skin than the peel treated with bread kvass, and further fattening and kneading operations are also greatly facilitated. The skins very well fit and are very durable, and in appearance, soft and soft, they are superior to normal cheese. The term of salt treatment by this method in vats lasts .8–20 hours instead of 8–12 days of treatment with bread juices.

An exemplary method of operation for the vat is as follows: a solution of hyposulphite or 15-40, an ammonium sulphate solution or 10- (1 soda solution or; ke solution of some other salt of the appropriate concentration) is prepared in a vat 20-40; one is dipped in a vat and left until complete impregnation with a solution Depending on the type of raw material and the desired degree of impregnation, the processing time is from 8 to 20 hours.

The subject matter of the invention.

The method of tanning raw leather or fur with preliminary conventional peeling and dezizolivaniem, characterized in that the wet hide or fur is treated with average composition of sodium or ammonium salts of mineral acids, such as; (. NaaSO4, Na.CO. ,, Na.jSOs, etc.