SU795502A3 - Method of making leather or fur hode - Google Patents

Description

one

The invention relates to the leather and fur industry and can be used to obtain leather or fur skins.

Known sposbb, in which raw skin or raw skins are soaked in an environment whose predominant component is water, and prepared as usual for pickling, then skin or skins by centrifuging, squeezing or draining partially free from them. water and in a liquid medium are exposed to picnic and tannic chemicals and, if necessary, treated with a fatty substance, then, in the manufacture of leather, the skin thus withdrawn is used for the purpose of additional processing or doubleting They are applied to neutralizing chemicals in a liquid medium, if necessary, tanning chemicals, as well as fatty substances.

In the practical implementation of this known method of making leather, the present time has been applied; exclusively aquatic. The same applies to fur skins l.

A disadvantage of the known method is that the removal of the aqueous media that are used for processing and those still containing chemicals, as well as the water used for the intermediate washing processes, creates a strong environmental pollution. Special problems are created by wastewater containing chromium, which is formed by tanning or tanning leather and fur skins that are resistant to high temperatures. Since this wastewater is produced in large quantities, this requires a large, economically unjustified HHbix waste disposal costs. In addition, the disadvantage is that a significant amount of chemicals does not participate in the manufacturing process, but is diverted from

0 STOCHNY1.1I waters.

There is a known method that involves the operations of fatting, degreasing, dyeing l and tanning 2 in organic solvent environments: in solutions that mix with water alcohols and ketones, for example, acetone. Since the skin and skins are hydrophilic and contain water, it was thought that when using organic dissolving media it was necessary to restrict only those that are mixed with water, and that only in this way are these dissolving media and chemicals dissolved in them penetrating into the tanned material. But this method of tanning has not found practical application because of the flammability of mixing them with water and dissolving water. As a result, the necessary expenses for their recovery are necessary.

The aim of the invention is to provide a method for manufacturing leather and fur skins, which drastically reduces the amount of harmful or difficult to convert into harmless wastewater and significantly saves chemicals.

This is achieved due to the fact that tanning and / or retanning are carried out in an organic medium that is not miscible with solvent and water, while the water content of raw hides is 50-80 wt.%, In the skin - 30-80 wt.%. Halogenated hydrocarbons, preferably chlorine or fluorine derivatives, are used as the organic solvent.

In accordance with the invention, it is provided that skin or pre-tanned skin with a water content of from 50 to .80 wt.% Or skins with a water content of 30 to 80 wt.% Are also subjected to organic, not mixing deis with water dissolving environment exposed to pickling chemicals. It is also possible to expose pre-hardened skin and hardened skins with the above water content, in an organic, water-immiscible, dissolving medium, to neutralizing chemicals. In the dissolving medium used, it is also possible to carry out drying and dyeing.

Leather or pre-hardened skins are exposed to picke and tannic chemicals without replacing the dissolving medium. It is preferable to use water-insoluble solvents, such as trichlorethylene and tetrachlorethylene. Famous chemicals used in old methods of making leather and fur skins can be used for pickling and tanning. The same applies to neutralizing chemicals. For the spitting and tanning performed in accordance with the invention, as well as for other processes, in particular, for retanning, fattening and dyeing, it is preferable to use apparatus similar to the known apparatus for degreasing hides and skins with solvents.

Tanning chemicals, as well as other necessary chemicals, in particular peak ones, are not previously dissolved in water, but added directly to the dissolving medium.

On the other hand, the applied chemicals, dissolved or suspended (dispersed) in an organic dissolving medium, can be added to the dissolving medium used in the method. The advantages of the invention are preserved in principle even when the chemicals used are first dissolved in water and a warm medium is added to the solution, and the amount of water used to pre-dissolve all chemicals entering the dissolving medium is determined so that the total amount of water in the process, it was a maximum of 400 weights of dry tanning material. According to the invention, chemicals insoluble in an organic dissolving medium that is not miscible with water are used for tanning or retanning. In principle, in the used dissolving medium, pickling and tanning of pickled and tannic chemicals dissolved in it can be carried out, in this case, the advantages of full use of chemicals are lost, as well as a significant reduction in the process. So. As used in the method according to the invention, especially when tanning, the dissolving medium is not withdrawn, but instead remains in the process (at the end of tanning it is pumped into a spare tank or distillation cube), any pollution of the environment by the wastewater of tannery is eliminated. The dissolving medium after the tanning process contains only the minimum amount of water and tanning chemicals and does not contain tannin chromium residue. Therefore, the applied chemicals are completely disposed of and the dissolving medium can be disposed of completely or at low cost. It is only when using chemicals that are soluble in the dissolving medium, residues of chemicals remain in it, which also do not enter the environment.

With appropriate process management, the method according to the invention allows to obtain dressed fur hides. With proper use, the pile is clean and not tangled. The skin and the fur of the skin do not differ in appearance or touch from the classically well-skinned leather or tanned fur.

In the following examples, all weight data in percent refers to the weight of skin centrifugation or fur materials.

Example 1. Dressing sheepskin.

Degrease the fur material and equalize the water content.

Nebula skins soaked in water and centrifuged to 55% of water content, soaked in water

Treat for 10 minutes with cold trichlorethylene in the proportion of 1 to the material, 3 l of trichlorethylene; The treatment is carried out in a wool-washing machine used in dry cleaning and in the leather and fur industry. Finally, trichlorethylene is transferred into a tank or a boiling cube, and the skins are centrifuged for some time.

Pickling.

Skins pretreated in this way are treated for 20 minutes in the described machine in the proportion of 1 kg of material, 7 liters of trichlorethylene and 2.3% of table salt (add undissolved), and I adjust the drum speed for the whole tanning and pickling process by the type of skins. Pickling lasts 60 min with the addition of 85% undiluted formic acid.

Tanning.

Not replacing the dissolving medium, 3.1% 4/12-base chrome tanning agent with 26% oxide content is added in undissolved form. The exposure time is 1 hour, after 15 minutes the dissolving medium does not contain a chrome tanning agent, which dissolves in the remaining water of the leather. The pile is completely clean. After that, 2.8% of synthetic tanning agent is added and the skins are processed for another 30 minutes. After this time, the dissolving medium, which still contains a minimum amount of water, as well as traces of tannic and picel chemical, but not containing chromium, is pumped either into a special tank for recycling or into a still cube. Finally, the skins are centrifuged for 3 minutes.

Evaporation of solvent and grease.

In the same machine, dissolving media (trichlorethylene) is converted into steam for 20 minutes. In conclusion, the skins are taken out of the machine and, for 1 hour at 45 ° C, fattened in the ratio of 1:15 (relative to the weight of the centrifugation) with 10 g / l of synthetic anionic fatty substance. Further operations — drying, breaking up, ironing — are carried out in the usual way.

The resulting skins have a shrinkage temperature (boiling point), in quality they correspond to fur hides dressed in the usual way, however, they are completely free of chromium in the pile.

PRI mme R 2. Dressing hides of red foxes (aluminous tanning).

Degrease the fur material and equalize the water content.

The soaked, washed and centrifuged fur material is treated according to example 1.

Pickling.

Trichlorethylene is added to the centrifuged fur material in proportions of 1 kg of centrifuged material, 6.5 liters of trichlorethylene and -2.3% of table salt. After 20 minutes, 1.1% formic acid (85%) and 1.1% glycolic acid are added.

(57%). Depending on the design of the machine, the speed can be either low (for a 50-pound car about 10 rpm) or at

 a fast rotating drum (for a 50 kg machine at about 24 rpm), the machine works with pauses.

Tanning

Not a replacement solvent medium

0, 5.6% potassium alumina is added; the drum rotates as if it had been pecked for 1 hour. Then 2.6% of liquid synthetic tanning material was added, followed by 30 minutes of rotation.

Neutralization.

Not replacing the dissolving medium, 2.5% sodium bicarbonate is added; the drum rotates continuously for 15 minutes. The dissolving medium, which also contains the minimum amount of water and tanning and pickling chemicals, is pumped into the tank for recycling or into the still cube.

c. Centrifugation of the hides continues for 3 min.

Evaporation of the solvent and fattening.

Evaporation of the solvent is carried out in a machine at 40-50 seconds for

0 25 min Then the machine is emptied; a typical fat ratio is achieved by 300 g / l synthetic anionic fatty substance. Further operations are performed.

5 in the usual way.

Temperature; hooray shrinkage of the hides treated in this manner Approximately 80 ° C, i.e. in contrast to treatment in the aquatic environment, with significantly lower costs of tanning chemicals, much better extraction of hides is achieved. The quality of fur skins. Corresponds to the quality of dressed in the usual way skins.

Example 3. Dressing skins

gnenka.

50 kg of soaked, washed, fleshy and centrifuged skins of a nest with a content of about 50% are treated in the machine described in

Example 1, 400 L of dissolving medium consisting of tetrachlorethylene containing 50 g / L of triolein for 5 minutes. 900 g are then added through an automatic dosing device.

formic acid (85%), dissolved in water in a 1: 1 ratio. After another 5 minutes of treatment, 600 g of 4/12 basic chrome tanning agent will be automatically added with a 26% content of chromium oxide dissolved in 1.5 liters of water during boiling. Processing lasts 40 min. After this, 1250 g of liquid 50% anionic synthetic tanning agent are also automatically added. Processing time 60 min. After that, the dissolving medium is pumped into the tank or still-water. The skins for some time are centrifuged by evaporation in a machine with the remainder of the dissolving medium removed and finally dried in a tumble dryer. The skins can be processed further in the usual way, and depending on the purpose of using the finished skins, they can be supplemented in an aqueous medium. The shrinkage temperature of the skins obtained to the boiling point, in terms of the quality of the skins, correspond to the skins made in the conventional manner. Pile practically does not contain chrome.

PRI me R 4. Dressing muskrats (aluminous tanning).

50 kg of soaked, washed, fleshy and centrifuged muskrat skins with a water content of about 60% are mixed in a machine of the type described in example 1 for 5 minutes with heating 400 l of dissolving medium consisting of trichlorethylene. Then 1.4% formic acid (85%) and 1.0% glycolic acid (57%) are added. Mix for 20 minutes. After this, 4.8% of aluminum-alum alumina (powder) is added, treated for 20 minutes and finally 2.8% of synthetic tanning agent (for example, Tannit AK, Example 1) is added and treated for 20 minutes. Neutralization is carried out with 2.8% sodium bicarbonate for 20 minutes. After this, the dissolving medium, which still contains a minimum amount of water, as well as tannic and pickling chemicals, is pumped to the tank for reuse. The skins are centrifuged for 3 minutes and, finally, by heating the air to 40-50 ° C, the dissolving medium is removed in the machine for 20 minutes. Then, the wet skins are removed from the machine and, after direct or intermediate drying in a tumble dryer, 300 g / l of synthetic anionic fatty substance are greased in a known manner. The finishing of the skins (molding, degreasing, cleansing) is done by ordinary methods. The shrinkage temperature of the skins thus isolated is approximately 0 ° C; in spite of the significant savings of pickle and tannic chemicals, the skins are better than the usual method with an aqueous medium,

Example 5. Bottling of chromium salts in alum marmots skins

50 kg of alum marmots with a 1:30 bath module (1 kg of skins - 30 l of water) are soaked with 2.5 g / l cm thickening agent, 50 g / l of boiled salmon and 0 g / l of fatty substance at 1-3 The centrifugation is followed by adjusting the water content in the skins to 40-50% and feeding it into a machine of the type described in Example 1 or into another appropriate apparatus with the addition of 800 liters of dissolving medium containing tetrachlorethylene, the medium being heated to for 10 minutes. Then, 1.25 kg of formic acid (85%), dissolved in 1.7 liters of water, is added, and the treatment time is 5 minutes. After this, 2.9 kg of 4/12 basic chrome tanning agent with 26% chromium oxide content is added and treated for 50 minutes. Then the dissolving medium is pumped into the spare tank for the purpose of re-disposal, the pelts are centrifuged for some time, then the medium is replaced with 400 liters of the same, but fresh dissolving medium. After 20 minutes, 2.4 kg of an anionic softening agent is added, mixed with 2 liters of water; process 10 min. After that, the dissolving medium is pumped into the second tank or the still cube, the pelts are centrifuged for 3 minutes, and then the residual dissolving medium is separated from them by heating the air to 70 s for 20 min. The skins removed from the machine are dyed and dried directly or after intermediate drying in the usual way by adding 5 g / l of anionic fatty substance. The shrinkage temperature of the finished skins is 100 ° C; the skins, despite significant chemical savings, are no different from skins that have been hardened in the usual way. The pile not only does not contain chrome, it is clean, fluffy and smooth.

Example 6. Treatment of sheepskin into leather for clothing.

All percentages refer to peak weight. After pickling, the sheepskin is washed for 30-60 minutes in 8% sodium chloride solution, then centrifuged or squeezed. To obtain a 60% water content, it is placed in a machine of the type described in Example 1, filled with a tetrachlorethylene dissolution medium in a ratio 1 kg mole and 10 liters of medium. Prior to this, 50 g / l of chloroparaffin with 40% chlorine and 10 g / l of fatty alcohol with a low ethoxy number (about 2-5 mol of ethylene oxide per 1 mol of alcohol) are added to the dissolving grease medium. The rojibe is stirred for 10 minutes, heating the dissolution medium to 350 ° C. Then add 2%

synthetic tanning agent dispersed in 5% trichlorethylene, and treated for 20 μC. Then 5% 4/12 basic chrome tanning is added with a 26% content of chromium dissolved in 10% water and stirred for 10 minutes. Thereafter, neutralization of 2% of the buffer salt in the pores should be carried out for 10 minutes. Retanning is carried out for 20 minutes with 10% synthetic tanning agent mixed with 10% tetrachlorethylene. The dissolving medium can be discharged into the working tank and reused. Then the skin is centrifuged for some time and dried in a machine at TOC for 10 minutes, freeing them from the dissolving medium. The skin that still contains water (water content of about 50%) is subjected to intermediate drying, then dyeing and greasing in a known manner. If, after intermediate drying, the skin still contains a significant amount of natural fats, it is possible to carry out a degreasing in a dissolving medium without hindrance. The resulting skin is heat resistant, uniform in color and different in special filling and face.

Claims (2)

Claims 1. A method of making leather or fur skins, comprising: . that the leather or skin is soaked in an environment whose predominant component is water, is prepared for pickling, then partially centrifuged, squeezed or drained, partially free from water, after which pickling is performed in a liquid medium, tanning and, if necessary, grinding, add neutralization and retanning characterized in that, with 10 in order to reduce the amount of wastewater, tanning and / or retanning is carried out in an organic water-immiscible solvent, with the water content in leather: 5 raw materials 50-80 wt.%, And in the skin of 3080 wt.%. 2. The method according to claim 1, characterized in that halogenated hydrocarbons are used as the organic solvent, preferably chlorine or fluorine derivatives. Sources of information taken into account in the examination 1. Stater F. Chemistry and technology of tanning, 4th ed., P. 319-320, 340. - 2. Weber X. Leather. 1969, pp. 8-11.