CS214054B1 - Method of manufacturing tannic leather - Google Patents

Abstract

The invention relates to the leather industry, the field of three-component tanning. It describes a shortened method of tanning leather from decalcified hides, which are not pickled, but are treated dynamically directly after acidification in a bath consisting of 20 to 200% by weight of water and 0.1 to 5% by weight of cationic substances such as condensation products of organic acids with polyamines, condensation products of amines or aqueous dispersions of epoxy substances, calculated on the hide weight. The subsequent tanning of the hide thus treated takes place very quickly, depending on the thickness of the hide within 24 to 48 hours. The invention can be used in all tanneries producing three-component leathers.

Description

The subject of the invention is a method of producing three-component leathers in a shortened manner. The essence of this method is the use of cationic substances that affect the penetration of concentrated tanning substances, especially natural or synthetic tannins into the leather. The hide is treated with the above-mentioned cationic substances before the actual tanning process. This method allows the hide to be processed without the operation of pickling and pre-treatment.

The current methods of rapid tanning are based on various methods of treating the hide, which block the amino groups of collagen by their anionic effect, thus allowing rapid penetration of even concentrated tanning substances. Some methods use chromium tannins to treat the hide, but when they are used, the leather produced does not have all the characteristic properties of three-component leather. There is also a risk that a certain amount of chromium salts will enter the wastewater. All of the above rapid tanning methods require that the hide be delimed and pickled.

Some of the disadvantages of the tanning methods used so far are eliminated by the process according to the invention, the essence of which is that delimed, possibly soaked, hides are used. This hide is directly treated in a bath consisting of 20 to 200% by weight of water and 0.1 to 5% by weight of a cationic substance. All cationic tanning lubricants can be used as cationic substances, as well as condensation products of organic acids, β polyamines, condensation products of amines, or aqueous dispersions of epoxy substances. After washing the hides thus treated, they are tanned in a bath containing 20 to 200% by weight of water and a synthetic or natural tanning agent, or a mixture thereof.

The amount of water used for tanning depends on the type of equipment in which the tanning takes place. The amount of tannins used is governed by the desired properties of the resulting leather, in most cases it is less than in conventional tanning methods. The resulting leather is evenly tanned, tanning takes place in 12 to 48 hours depending on the weight class of the leather used.

The process according to the invention is further illustrated by the following examples, which are just some of the many possible variants.

Example 1.

The slivers treated in the usual operating manner are washed with a flow of water at 30 to 35 °C for 30 to 10 minutes in a conventional tannery barrel. The following sequence of operations is then carried out:

Descale: 80 X-weight of water 38 °C

X mass, ammonium sulfate 0.5 hours.

0.04 X mass of enzymatic mordant 0.5 hours

0.4 X mass of formic acid »

0.4% by weight sulfuric acid 1 hour

Washing: flow rate · vMou 25 °C _e 15 min.

Pretreatment: 50 X wt. water> 30 to 38 °C

X wt. quaternized with natural oils (Syntamin KY)

Tanning: 15% by weight of synthetic exchangeable tiχ ’ •'va 24 to 48 hours.

from Bulfone phenols and sulfate leaches (Kortan M)

214,054% by weight of natural tannin (Quobracho)

0.5% by weight of a mixture of sulphated fish meal with the addition of mineral oils (Lubricant M)

Washing: with water flow 28 °C 0.5 hour.

Further operations are carried out according to normal operating methods.

The percentage of use is calculated in % by weight per unit weight.

Example 2.

The pig fat prepared in the usual operating manner is further processed in the following way:

Washing: with water at 35 °C, flow rate 1 hour.

0.3% ethoxylated adduct of the above alcohols (Dubaryl) 0.5 hours.

until morning in peace

Washing: through water flow 35 to 38°C 10 minutes Descaling: 200% water 35 to 38°C 2% ammonium sulfate 0.5 hours 0.2% hydrogen peroxide 0.5 hours 0.4% formic acid 1 hour Washing: through water flow 28 to 30°C 15 minutes Pre-treatment: 50% water 28 to 30°C quaternized salt of natural oils 3 hours

(Syntamin KY)

Tanning: 15% by weight of synthetic exchange tannin 24 hours.

(Kortan M) from sulfonated phenols and sulfite leaches

Washing: running water 30 °C 0.5 hour.

Further operations are carried out according to normal operating practices.

The percentage of application is calculated in % by weight per unit weight.

Claims (1)

A process for the production of tanning leather from decalcified or decanted wort, which is only acidified with an inorganic or organic acid or a mixture thereof, to a pH value of the cut of the wort of 5 to 7, characterized in that. That the treated soil is treated dynamically in a bath consisting of 20 to 200% by weight. % water and 0.1 to 5 wt. cationic substances, which are cell quaternized salts of natural oils or alkylpolypropylenepolyamines, the number of amino groups of which is more than the number of propylene groups of 1 to 5 and the alkyl contains 12 to 24 carbons with saturated and unsaturated bonds and quaternized with inorganic and organic acids with one to eight carbon atoms; or an aqueous dispersion of epoxy substances followed by a mixture of synthetic and natural tannins or separate natural or synthetic tannins.