Method of treatment of animals' skins

FIELD: material processing.

SUBSTANCE: method provides degreasing and/or drying of animals' skins. According to method, skins, being subject to degreasing and/or drying, are brought in contact with one or more extractants. At least one dissolvent, selected from group consisting of dimethyl ether, methylal, dioxolane, diethyl ether and methyl ethyl ketone, is used as single dissolvent. Sheep, cows', goat's or pig's skins are subject to degreasing and drying. Process is carried out in stator or rotor reactor under pressure of 1-12 bar and at temperature between 5°C and 40°C.

EFFECT: improved efficiency of cleaning; improved ecological safety of process.

14 cl, 1 dwg, 4 ex

 

The present invention relates to a method of treating skins of animals. More specifically the present invention relates to a method of degreasing and/or drying animal skins, hides and skins. Skins, processed according to the method of the invention may be used in the usual way, for example, for the production of tanned leather.

Along with ways that use perchloroethane or trichloropropane solvents, one of the most commonly used methods of degreasing wet skins is that these skins organic solvents and nonionic and/or anionic detergent in the drum in an aqueous medium to emulsify fats.

DE-OS 2522902, for example, describes degreasers containing nonionic and/or anionic surface-active agent (surfactant) as auxiliary substances in the solvent is alcohol-based.

WO 93/18188 describes the application of a degreasing means on the basis of non-ionic emulsifiers of the type alkoxysilanes fatty alcohol for degreasing of hides and skins. These nonionic emulsifiers contain a mixture of ethoxylates C12-C18fatty alcohol, on average, more than 6 ethoxy (EO) groups in the molecule and (b) of these ethoxylates of fatty alcohols with more than 3 EO groups in the molecule, and (i) fatty alcohols of component (a) and (b) have ideascale less than 10 and (ii) component (b) is present in the amount of 2-10 wt.% in the calculation for the sum of (a) and (b).

However, the main drawback of these methods is that the resulting wastewater will contain detergents, fats and salts that are difficult to decompose biochemically and/or recycling. Another disadvantage is that the result achieved by this method is not as effective as the result achieved by methods using perforirovannykh or trichloropropane solvents.

Another way degreasing wet skins is that these skins hydrocarbons, such as oil derivatives, white spirit and Nonylphenol. The drawback of these methods degreasing is that water is not soluble in the used solvent. Therefore, the skin should be dried in a separate step of the way. In addition, these methods degreasing produce highly contaminated wastewater containing fats, hair, meat, salt and hydrocarbons. On the other hand, dry skin is usually chlorinated degreasing solvents, such as PER (tetrachlorethylene) and TRI (trichloroethylene). However, as we know, these solvents are harmful to human health and harm the environment.

Methods of drying hides and skins described, for example, in U.S. patent 3444625. This document relates to the ways in which water is removed from the slurry skins extraction with organic solvents, e.g. who, such as formal, acetone, chloroform or dichloromethane. The disadvantage of these methods is that the skins should be degreased in a separate stage.

The present invention is to provide an effective alternative to the known method of removing neutral fat contained in dry or wet skin; moreover, this method is less toxic and/or less polluting to the environment, and also has the additional advantage that the water contained in the skins, can be extracted together with fat.

The objective of the invention is solved by the provision of a method of degreasing and/or drying of the skins of animals, including the state of contact of skin with one or more extracting solvents. The term "extracting solvent" means an organic solvent that can dissolve both fats and water. Note that the term "skins" often refers to the skins of small animals such as pig, cow or sheep, while the term "hides" refers to the skins of large animals, such as cow or horse. However, the term "skins" is also used in the technique in a General sense to describe all of the skins of animals, as it will be used next.

Extracting the solvent of the present invention contains at least one solvent selected from the group consisting of dimethyl ether (DME), met Lala, dioxolane, diethyl ether and methyl ethyl ketone. For reasons of their easy recovery and security are preferably used such solvents, which are gaseous at atmospheric pressure at room temperature. Preferably using a mixture of extracting solvent, which comprises at least 10 wt.%, more preferably at least 15 wt.% and most preferably at least 25 wt.% DME calculated on the total amount of extracting solvent. Preferably the mixture of extracting solvents, along with DME, includes at least one extracting solvent selected from the group consisting of metella, dioxolane, diethyl ether, methyl ethyl ketone, ethanol, propanol and isopropanol, and more preferably at least one extracting solvent selected from the group consisting of metella, dioxolane, diethyl ether and methyl ethyl ketone. Even more preferably used a mixture of matilla and dimethyl ether. However, it is most preferable as the extracting solvent used dimethyl ether.

Although less preferred, but the above extracting solvents or mixtures of extracting solvents can also be used as a mixture with one or more solvents, the mixture is Vasilisa with fats, such as esters, including methyl acetate, ethyl acetate and propyl; hydrocarbons, including n-pentane, isopentane, cyclopentane, hexane, cyclohexane, heptane, white spirit and petroleum ether; glycols, such as 2-ethoxyethanol and 2-butoxyethanol; or halogenated hydrocarbons, including CHF2CH2CF3, CF3CHFCF3, CF3Br and CF3CH2F. Preferably the compounds comprise at least 35 wt.%, more preferably at least 50 wt.% and most preferably at least 70 wt.% extracting solvent according to the present invention based on the total number of the used solvents. More preferably the mixture contains at least 10 wt.% DME calculated on the total number of used solvents.

Dimethyl ether (DME) is gaseous under standard atmospheric conditions. It can be easily Origen cooled to -25°at atmospheric pressure or compression to a pressure above about 5 atmospheres at room temperature. Liquefied dimethyl ether has the advantage that it easily dissolves the majority of the fats and dissolves about 6.3 wt.% water at 20°C. It has a specific weight 0,661, which is the density of a substance divided by the density of water and the latent heat of vaporization 96,6 cal/g

The way is about the present invention can be applied as the initial stage, to remove fat and/or water from fresh hides, skins or wet skins, but it can also be the stage degreasing in a subsequent method of tanning. Thus, hides, which can be used in the method according to the present invention, can be any skins, which are also suitable for conventional degreasing and/or drying.

Note that the term "skins"used in the document is intended to outline fresh, wet and dry skins of animals. The term "fresh skin" means skin, obtained directly from the slaughterhouse, while the term "wet skin" means skin, which has already passed through one or more of the processes of obtaining tanned skin, such as pickling, maturation, soaking in lime water, dehairing, sink, cutting hair, waxing or scraping meat. The term "dry skin" means skin that has undergone chemical preservation, such as, for example, processed salt, and/or physical preservation, such as, for example, drying, cooling or freezing.

Thus, skins, suitable for processing by the method of the present invention include skins that were not processed salt or preservatives and are obtained from the evisceration of animals, or of ways of converting the skins; hides, salt freshly cut, polyserve skin, i.e. the skin, to which were partially dried and, possibly, cool, or polulegalnye skins, ie skins, which have undergone some ways to get tanned leather, tanned skin, i.e. skin that has undergone all stages of the tanning process, except stages degreasing and/or drying; the skins that are manufactured items, which should be subjected to a similar method, called dry cleaning; and skins obtained from enterprise tanned sheep skin, which may degrease the skin before or after pickling.

The word "tanning"used in the description, is used in its usual meaning, i.e. to indicate the General method of conversion of raw animal skins in the skin.

Skins, subject to removal by the method of the present invention, preferably chosen from the group consisting of sheep, cows, goats and pigs. Skins of sheep, goats or pigs should be degreased in a larger proportion than cowhide. Note that the experts it is clear that the term cowhide also includes ox-hides.

Way similar to the way when dealing with a fresh, dry, providername or tanned skins. The fact that the skins can be chemicals, such as salt, acid or alkaline detergents usually do not impact adversely on the way degreasing and/or drying the above ex is rigorously solvents and, therefore, these skins can be used in the method of degreasing and/or drying of the present invention. Moreover, specialists in this field of technology are aware that the method according to the present invention is open to changes, in accordance with the special situations in the tanning business, where a method should be carried out, or in the processing of special skins subjected to degreasing and/or drying.

The method of extraction according to the present invention can be performed in any reactor or vessel, usually used in the methods of degreasing of hides and skins. In the preferred embodiment, this method is performed under pressure in a conventional reactor, in which the content is in a static condition and which contains an appropriate system for wetting the skins. In the so-called static reactor skins can be folded at the bottom of the reactor or in a basket, which is then injected into the reactor. However, some of the pollution originating from parts of the reactor that are not available any cleaning, and pipe may stick to the skin. In addition, some amount of water and/or dirt may accumulate in the folds. Therefore, in a preferred embodiment of the present invention skins are placed in the reactor in a vertical position, while the surface is wetted down one is m or more extracting solvents, or in another situation where they can be completely wetted by one or more extracting solvents.

In another preferred embodiment, the method is performed in a conventional rotary reactor. The advantage of the rotary reactor is that the boundary surface between the skin and extracting solvent (solvents) is improved due to rotational, oscillatory or vibratory motion, thereby reducing the extraction time and activating the process.

The total amount of extracting solvent (solvents)used in the method of degreasing and/or drying of the present invention, the applied pressure and the temperature in the reactor is selected from a calculation of the total weight of the skins, content of fat to be removed, the water content in the skin revealed by the analysis of whether the solvents, miscible with fat, and possible previous treatments. For example, pressure to be applied depends on how the dosage extracting solvent and the number (quantity) and type (s) used extracting solvent (solvents). However, usually apply a pressure from 1 to 12 bar, preferably less than 10 bar and most preferably less than 8 bar.

In order to remove the fat most effectively, in the reactor support temperature is preferably below 50&#HWS, more preferably below 45°and most preferably below 40°C. the Applied temperature is preferably above 5°C, more preferably above 10°and most preferably above 15°C. This temperature is usually achieved by adjusting the temperature of the steam cycle in the reactor or by heating or cooling the reactor. High extractive efficiency of one or more extracting solvents according to the present invention can operate in a wide temperature range, but is preferably applied temperature above room temperature. Most preferably applied at temperatures ranging from 20 to 35°C. in order to obtain reproducible results, the temperature is usually maintained within the range of 5% of the set temperature.

Before adding one or more of the extracting solvent in the reactor and in order to guarantee safety, it is preferable to apply appropriate measures such as the introduction of the inert atmosphere in the reactor prior to contacting the skin with one or more extracting solvents, possibly in combination with one or more solvents, miscible with fat. More preferably, the reactor remains under inert atmosphere during the greater part or all of the degreasing and/or drying. In the preferred embodiment, for this purpose, when enaut CO 2or N2or other inert or extinguishing gas. Maintaining a constant pressure by means of inert gas during the extraction process provides additional security, and it adds energy in the process.

During the degreasing and/or drying processing one or more of the extracting solvent, possibly in combination with one or more solvents, miscible with fat, according to the present invention can continuously dosed into the reactor, and refers to the fact that during a certain period of time, the combined solvent is continuously added to the reactor. Dosing extracting solvent (solvents) in the reactor may also be performed periodically during the operation; in this case, the expert is able to choose the optimal time intervals and the optimal amount of extracting solvent (solvents) and possibly optimal quantities of solvent (solvents), mixed with fat to be normal dosage experimentation. The combination of these methods is also possible. Examples of combinations of such methods include, for example, the way in which the extracting solvent (solvents) and possibly solvent (solvents), mixed with fat, first add continuously, then add stopping the pad from sliding the t, and then add continuously. However, continuous operation of the dosage should be preferred. In a particularly preferred variant of extracting solvent (solvents) and possibly solvent (solvents), mixed with fat, add, while the liquid containing extracting solvent (solvents), it is possible that the solvent (solvents), mixed with fat, water and fat, which is hereinafter referred to as the extraction liquid is removed from the reactor. In an even more preferred embodiment, the extraction fluid selected so clear. Most preferably obtained extracting solvent (solvents) and, perhaps, received the solvent (solvents), mixed with fat, then recycle to the reactor.

It is desirable to maintain a certain degree of moisture of the skin, for example, to maintain flexibility of the skin, or if it is useful for the following stages of the method of manufacturing of leather, a small amount of water may be added to the extracting solvent (solvents) and/or solvent (solvents), mixed with fat, if used. In a particularly preferred embodiment, the desired amount of water added to the extracting solvent (solvents), which recycle to the reactor. Thus, by changing the value of the amount of water in the solvent (the solvent) the degree of drying can be easily adjusted, and get the skin the desired degree of humidity.

Preferably the method includes removing the extracting solvent (solvent)containing residues of fat and/or water from the reactor and transporting them in the first vessel, the heated solvent (solvents) in the first vessel, transporting the vapor phase formed during this heating, the second vessel, a vapor condensation in the second vessel, and the flow of diluent (s), regenerated thus, in the reactor. The method may further include removing the liquid phase from the first vessel and transporting it in a third vessel, instant boiling or evaporation of the extracting solvent (solvent)contained in the liquid phase, the flow extracting solvent (solvents) in the second vessel directly or through the fourth vessel.

When the skin was degreased and dried to the desired degree, the extraction liquid is removed from the reactor, preferably in a closed circuit. Usually this fluid will contain residues of fat and proteins. Preferably the liquid allocate extracting solvent (solvents) and most preferably recycle in the process. Received the skins will contain a certain amount of adsorbed extracting solvent (solvents) and possibly solvent (p is Stroiteley), miscible with fat. This solvent (solvents) are removed by applying temperature and/or vacuum control or Stripping with an inert gas. Preferably, this solvent (solvents), adsorbed skin is evaporated and then regenerate. Most preferably the combined solvents, regenerated thus, recycle to the reactor. The method will be considered complete if the total amount of solvents, still absorbed by the skin, is less than 5 g per 1 kg of processed hides, skins, more preferably less than 2 g, even more preferably less than 1 g, and most preferably less than 0.5 g per kg of processed hides and skins, as determined by sampling the vaporized gases.

If DME is used as extracting solvent or as one of the extracting solvent used in the method of degreasing and/or drying of the present invention, the presence of water and its solubility in DME improves the security of the method in relation to Flammability, since the minimum and maximum values of reduced Flammability. Due to its high diffusion coefficient DME easily penetrates the skin, dissolving the fat contained in it, with the formation of an extraction fluid, which, along with water and fats, will mostly contain proteins without polluting of Titkov.

Preferably the skins are in contact with one or more extracting solvents and possibly solvents, miscible with fat, according to the present invention for a certain period of time. The desired extraction time depends on the content of fat and water in the skins, the difficulties of their extraction and the desired result. Typically, the extraction time is less than 10 hours, more preferably less than 8 hours, even more preferably less than 4 hours and most preferably less than 1 hour. Preferably the skins in contact with the extracting solvent (solvents) and possibly solvents, miscible with fat, for more than 10 minutes, more preferably more than 20 minutes and most preferably more than 30 minutes. In the preferred embodiment, there is a possibility of sampling extraction fluid during the extraction process to determine the point at which the skin sufficiently degreased and/or dried using conventional methods such as, for example, the method of Karl Fischer (Karl Fisher) to determine the percentage of water content or determination of fat and water evaporation of the extracting solvent (solvents) and then weighing the residue, thus obtained. Usually, when a well-known type of skins to be processed, i.e. the breed of the animal, is also the area where the animal came, and his food, the specialist can easily find out the fat content in the skin. For example, the specialist is known that the skin of the Spanish Merino sheep usually contains about 12% fat, while the skin of the Australian and English sheep usually contains more than 30% fat. In addition, it is known that pork skins have a high fat content.

The method according to the present invention can be obtained almost completely dry and clean skin. The method according to the present invention allows to degrease the skin to the percentage of more than 50 wt.%, more preferably more than 75 wt.%, even more preferably more than 90 wt.% and most preferably more than 98 wt.% in calculating the total amount of fat originally present in the fresh skins. The method according to the present invention allows to dry skins, which are not subjected to pre-drying, to the percentage of preferably more than 30 wt.%, more preferably more than 50 wt.%, even more preferably more than 75 wt.% and most preferably more than 90 wt.% in calculating the total amount of water initially present in the fresh skins. For some purposes, however, it is necessary to maintain a certain level of humidity skins (see above).

As discussed above, the required number extragonadal the diluent (s), to achieve a satisfactory percentage of degreasing and/or drying, depends on the type (types) of extracting solvent (solvents), fat and water in the skins to be processed, used or not extracting solvent (solvents) in combination with solvents, miscible with fat, according to the invention and the extent to which I wish to degrease and/or dry skin. However, in General, the application 40 litres of extracting solvent (solvents) for 1 kg of skins to be degreased and/or drying, more preferably 20 liters, and most preferably less than 5 liters per 1 kg of skins subjected to degreasing and/or drying, will be enough to get the skins, which is almost dry, i.e. removed more than 90 wt.% water, based on the amount of water contained in the fresh skin, and is absolutely clean, i.e. removed more than 98% fat, based on the amount of fat contained in fresh clothing. Note, however, that the longer the extraction time, the less solvent to achieve the desired results.

Preferably used is at least 0.5 liters per 1 kg of skins subjected to degreasing and/or drying, more preferably at least 0.75 liters, and most preferably at least 1 liter of extracting solvent (solvents) for 1 kg W the ur, subjected to degreasing and/or drying.

The present invention is illustrated by the following non-limiting examples. Next, a preferred example of a suitable configuration of the reactor and together existing recirculating system for carrying out the process of the present invention shown in the attached drawing and will be described below.

Example 1

One fresh sheep's clothing and one fresh goatskin obtained from slaughterhouse recent rend stuck with the remnants of wool, and dirty (unwashed and untreated), were placed on the bottom of the metal basket, which serves as a support for the sample, the sheets 30×30 cm Then the basket was introduced in a static reactor with a capacity of 140 liters under the pressure of 4.1 bar. Then the reactor was injected gas CO2. The reactor was purged of dimethyl ether (DME) to remove air and CO2and created a vacuum. All equipment is weighed. The equipment weighed 357 kg and calculated that the combined weight of the skins was 2240, Then added 53 kg of liquid DME with a speed of 17 kg/min Measured temperature, the reactor was heated to 27°C and kept for 1 hour at this temperature. During this hour approximately 17 kg/min extraction liquid containing DME was removed from the bottom of the reactor and then recycled to the top of the reactor by a pump with a flow rate of 17 kg/min Thus, the skin is nogometna were washed with DME. After 1 hour of DME were unloaded from the reactor, introducing a CO2and the combined gases are taken in the breathing zone. Skins are then weighed. In the first weighing skins weighed 1790 due to the presence of adsorbed DME. After 6 hours of adsorbed DME was evaporated, and the skins weighed 1640, This means the total loss of weight 640 g of water and fat, which is 28.6% of the weight of raw hides and skins.

Analyzing an extraction liquid during the process, it is possible to calculate not only the number of remote water and the quantity of the removed fat. It is found that the extraction of fat was effective, i.e., removed more than 99% of the fat contained in the skins.

Example 2

Wet sheepskin and wet goatskin called "bilateral" (pure, without meat, nedobity), with wool, cut for evaluation, were placed on the underside of the metal basket, which serves as a support for the sample, the sheets 30×30 cm, and then the basket was introduced in a static reactor with a capacity of 140 liters. Skins together weighed 2180, he Used the method described in example 1. However, recycling is not conducted. Instead, spend 4 wash 15 kg of DME in the chain pump. Each time the input DME pumped with a speed of 17 kg/min After 60 min of DME was unloaded from the reactor, and the skin was weighed. In the first weighing skins weighed 1630 due to the presence of adsorbed DME. After 12 hours of adsorb the integration of DME was evaporated, and skins weighed 1270 This means the total loss of weight 910 g of water and fat, which is 41.7% of the weight of raw hides and skins.

Dried and fat-free skins obtained by the methods of examples 1 and 2 were almost dry, but some water still present in the folds. In examples 3 and 4 skins were hung, and their surfaces were specialise from top to bottom.

Example 3

Two dry two-way hides, sheep and goat, (pure, without meat, dry, nedobity), with wool, cut for evaluation were introduced in a static reactor with a capacity of 140 liters. They hung in a vertical position and supported by the edges of the metal basket. Folds that could accumulate dirt and/or water, was absent. Skins together weighed 1230 Applied the method described in example 2. Consequently, spent 4 wash 15 kg of DME in the chain pump, and dimethyl ether present in the reactor, each time was replaced. Input DME pumped with a speed of 17 kg/min New quantities of dimethyl ether was introduced approximately every 15 minutes, and samples were taken circulating DME. After 60 minutes (while leveling) DME were unloaded from the reactor. Then created a vacuum for 2 hours, and the skins were weighed. In the first weighing skins weighed 1030 g due to the presence of adsorbed DME. After 2 hours of adsorbed DME was evaporated, and the skins weighed 1040 g, as and for the hygroscopic properties adsorbirovannoi a certain amount of atmospheric moisture. This means the total loss of weight 190 g of water and fat that is 15,44% of the weight of raw hides and skins. The skins were almost dry.

The analysis of these skins method soxlet standard IUC-4/ISO 4048 using methylene chloride showed that the treated goat and sheep skins contained less than 1 and 2% fat, respectively.

For these skins had a higher extraction efficiency than wet skins of example 2.

Example 4

Two small pieces of wet cowhide, i.e. pickled cow hides and cow hide (clean and without meat, wet, obezbashennye, nedobity) weight 560 g and 700 g, respectively, were hung in a vertical position near the bottom metal baskets because of their small size, and supported by the edges of the basket. Then a metal basket was introduced in a static reactor with a capacity of 140 liters. Folds that could accumulate dirt and/or water, was absent. Used the method described in example 2. Consequently, spent 4 wash 15 kg of DME in the chain pump, and dimethyl ether present in the reactor, each time was replaced, as if it was entered from the possible installation of recirculatory. Input DME pumped with a speed of 17 kg/min After 60 minutes (while leveling) DME were unloaded from the reactor. Then created a vacuum for 10 minutes, and the skins were weighed. In the first weighing skins weighed the 270 g and 340 g respectively. After 2 hours, the weight of both skins was still the same. This means the total loss of weight 290 g and 360 g, respectively, water and fat that 48.2% and 51.4%, respectively.

The analysis of these skins method soxlet standard IUC-4/ISO 4048 using methylene chloride showed that the treated cowhide contained less than 1% fat.

A preferred example of a suitable configuration of the reactor and together existing recirculating system for carrying out the process of the present invention shown in the attached drawing.

This configuration includes a static or rotary reactor, known in fact and sometimes called a "digester"to bear skins subjected to degreasing and/or drying. The reactor 1 includes an input 2 for fresh extracting solvent (solvents) and exit 3 for an extraction liquid containing, for example, excess fat, and proteins, and water. Output 3 is connected by a pipeline with a reboiler 4, equipped with a heating element (not shown). The bottom of reboiler 4 is connected to the evaporative drum 5, while the top of reboiler 4 is connected with the top of the reservoir condenser 6 to the regenerated extracting solvent (solvents), as will be explained below. Although the top of the evaporative drum 5, in principle, can be connected directly or with ver the om reboiler 4, or with the top of the collector 6, preferably combined with additional vessel, in this example, the regeneration vessel 7. Such vessel may be used, for example, to check whether there is water or residues in extracting the solvent coming from the evaporative drum 5. To close the loop, the bottom of the manifold 6 is connected to the input 2 of the reactor 1. Next, each vessel 6 and 7 is provided with a pipe for the removal of the regenerated solvent (solvents), which must be recycled.

If an extraction liquid contains DME, recirculating system usually works like this: skin degreasing and/or dried in the reactor 1 at about 25°and 4 bar; liquid contents of the reactor 1 is pumped into the reboiler 4, where the extracting solvent (solvents) is distilled at a slightly higher temperature and pressure, for example, approximately 35°and 6 bar; vapor phase formed during the distillation, flows in the collector 6, where it condenses to a liquid at about 25°and 4 bar; regenerated extracting the solvent (the solvent) is fed into the reactor 1.

If the number of extracted fat and remote water in the reboiler 4 exceeds a predefined threshold, for example 50% of the content of reboiler 4, extracted fat and water is pumped into ispai is entrusted drum 5. In the evaporation drum 5 extracting solvent (solvents) boil or quickly evaporated, for example, at 45°and 8 bar, and the resulting vapor phase enters the regeneration vessel 7, where it condenses in conditions similar to the conditions in the reservoir 6. Condensed extracting solvent (the solvent) is injected into the reservoir 6, and fat residues and water removed from the bottom of the evaporator drum and is collected in barrels.

Found that the method described above is particularly effective for the recovery and recycling of DME and other extracting solvents.

1. Method of degreasing and/or drying of the skin which comprises contacting the skin subjected to degreasing and/or drying, with one or more extracting solvents containing at least one solvent selected from the group consisting of dimethyl ether, matilla, dioxolane, diethyl ether and methyl ethyl ketone.

2. The method according to claim 1, in which the extracting solvent is dimethyl ether or a mixture of solvents containing dimethyl ether.

3. The method according to claim 2, in which the solvent mixture contains at least 10 wt.% dimethyl ether in the calculation of the total amount of solvent.

4. The method according to any one of the preceding paragraphs, in which the skins are selected from the group consisting whom her sheep, cow, goat and pork skins.

5. The method according to claim 1 or 2, in which one or more extracting solvent used in a mixture with one or more miscible with fats solvents selected from the group consisting of esters such as methyl acetate, ethyl acetate and propyl; hydrocarbons such as n-pentane, isopentane, cyclopentane, hexane, cyclohexane, heptane, white spirit and petroleum ether; glycols, such as 2-ethoxyethanol and 2-butoxyethanol; and halogenated hydrocarbons such as CHF2CH2CF3, CF3CHFCF3, CF3Br and CF3CH2F.

6. The method according to claim 1 or 2, which is carried out in a static or rotary reactor.

7. The method according to claim 1 or 2, which is performed under a pressure from 1 to 12 bar and at a temperature between 5 and 40°C.

8. The method according to claim 1 or 2, in which the skins are in contact with one or more extracting solvents during the period of time between 10 minutes and 10 hours

9. The method according to claim 1 or 2, in which the skins to degrease the percentage of more than 50 wt.% in calculating the total amount of fat originally present in the fresh skins, and/or dried to a percentage greater than 30 wt.% in calculating the total amount of water initially present in the fresh skins.

10. The method according to claim 1 or 2, comprising the stage of: the location of the skins subjected to degreasing and/or the drying, in the reactor, the reactor inert atmosphere and contacting these skins with one or more extracting solvents, measuring these extracting solvents or continuously, or periodically, or in combinations thereof, in a reactor.

11. The method according to claim 1 or 2, in which one or more extracting solvents emit after contact with the skins and then recycle.

12. The method according to claim 11, which includes stages: the removal of the extracting solvent (solvent)containing residues of fat and/or water from the reactor and transporting diluent (s) in the first vessel, the heated solvent (solvents) in the first vessel, transporting the vapor phase formed during this heating, the second vessel, a vapor condensation in the second vessel and the flow of diluent (s), regenerated thus, in the reactor.

13. The method according to item 12, which includes an additional stage: removal of liquid phase from the first vessel and transporting it in a third vessel, instant boiling or evaporation of the extracting solvent (solvent)contained in the liquid phase, the flow extracting solvent (solvents) in the second vessel directly or through the fourth vessel.

14. The method according to claims 1 or 2, which is used from 0.5 to 40 l extracting solvents n is kg of skins.



 

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2 cl, 4 tbl, 6 ex

FIELD: fur industry.

SUBSTANCE: invention is directed to processing fur sheepskin intended for manufacturing clothing, headgears, footwear parts and other fur items. Crude fur sheepskin of all preservation types is subjected to soaking, first degreasing, squeezing, haircutting, and fleshing according to known technology. Then fur sheepskin is subjected to additional processing in aqueous solution of sodium chloride (15-20 g/L) and nonionic surfactant composition (1-2 g.L) for 2-6 h at 30-32°C. After second degreasing and washing, pickle salting is carried out for 20-24 h. 4-6 hours after the beginning of pickle salting, processing solution is supplemented by 3-5 g composition of nonionic surfactants (1:1 mixture of Neonol AF 9-12 and syntamide 5). Finally tanning and greasing are performed.

EFFECT: improved performance characteristics fur sheepskin intermediate product.

2 cl, 1 tbl, 5 ex

FIELD: fur industry, in particular, process for pickling of sheepskin fur coats and raw fur material.

SUBSTANCE: method involves pickling fur sheepskins in solution such as sour-milk composition having titratable acidity of at least 300 T, lactic acid concentration of at least 25 g/dm3 and medium active reaction below 3.5; providing said process at temperature of 30±2 C during 16 hours at variable mechanical action, with liquid to acid ratio of 7, sodium chloride consumption of 20 g/dm3.

EFFECT: improved quality of fur sheepskins due to reduced curling of hair-covering and improved elastoplastic properties thereof.

4 tbl, 4 ex

FIELD: defatting of crude sheepskin-and-fur material.

SUBSTANCE: method involves treating crude material in bacterial suspension having lipolytic activity of 20-30 units/g and proteolytic activity of 2.5-3.5 units/g. Suspension contains product of total microorganism vital activity used in an amount of 4-8 g/dm3, synthetic surfactant used in an amount of 0.25-0.5 g/dm3, and prokaryotic crop of Pseudomonas sp. type used in an amount of 107-109 cells/cm3, water the balance. Treatment is conducted at temperature of 40±2 C during 45 min by providing mechanical actions, and liquid coefficient of 7-10.

EFFECT: improved quality of defatting sheepskins, improved elastoplastic properties and reduced level of toxic contamination of sewage water.

3 dwg, 4 tbl

FIELD: leather industry.

SUBSTANCE: method comprises pickling, tanning, and neutralizing the semifinished item. During pickling and subsequent tanning, the picking liquid is provided with acetate sodium in amount of 0.2-0.5 % and, then, chromic tanner in amount of 1.5-1.8%. The tanning is carried out until the pH of the solution reaches 4.2-4.4.

EFFECT: enhanced quality of tanning.

2 tbl

FIELD: fur industry, in particular, method for evaluating pickling quality of leather web in tanning of fur and sheepskin raw material.

SUBSTANCE: method involves determining quantitative pickling characteristic of leather web of semi-finished product by using time of solving thereof in alkaline solutions, said time depending on number and kind of intermolecular bindings destructed during pickling. Solving of collagen in alkaline solutions depends upon nature of preliminary acidic preparing procedure. Solving is provided in aqueous solution of potassium hydroxide having concentration of 150 g/l and temperature of 18-20 C. Derma solving time is found after preliminary thermal processing at temperature of 60-65 C during 1.5 hours. Method may be employed both in production of fur and sheepskin products and in fur processing.

EFFECT: wider operational capabilities and reduced time for determining quantitative pickling characteristic of skin web.

1 tbl, 1 ex

FIELD: fur industry, in particular, method for evaluating pickling quality of leather web in tanning of fur and sheepskin raw material.

SUBSTANCE: method involves providing testing on parallel groups of fur sheepskin after pickling on three topographic portions of sheep skin surface: skirt, spine and neck portions; processing samples of each group with acid-salt solution for 24 hours; withdrawing sheepskins of each group from acid-salt solution in predetermined time intervals; removing excessive liquid; placing said samples into tensile testing machine and stretching lengthwise of spine line by 40% relative to initial length thereof; holding samples in stretched state for 1 min and withdrawing from tensile-testing machine; leaving samples in free state for 10 min; determining residual elongation value in mm.

EFFECT: reduced time for determining quantitative pickling characteristic of skin web.

2 tbl, 2 ex

The invention relates to light industry and can be used in fur production during the process of degreasing hair and leather fur skins

FIELD: fur industry, in particular, method for evaluating pickling quality of leather web in tanning of fur and sheepskin raw material.

SUBSTANCE: method involves providing testing on parallel groups of fur sheepskin after pickling on three topographic portions of sheep skin surface: skirt, spine and neck portions; processing samples of each group with acid-salt solution for 24 hours; withdrawing sheepskins of each group from acid-salt solution in predetermined time intervals; removing excessive liquid; placing said samples into tensile testing machine and stretching lengthwise of spine line by 40% relative to initial length thereof; holding samples in stretched state for 1 min and withdrawing from tensile-testing machine; leaving samples in free state for 10 min; determining residual elongation value in mm.

EFFECT: reduced time for determining quantitative pickling characteristic of skin web.

2 tbl, 2 ex

FIELD: fur industry, in particular, method for evaluating pickling quality of leather web in tanning of fur and sheepskin raw material.

SUBSTANCE: method involves determining quantitative pickling characteristic of leather web of semi-finished product by using time of solving thereof in alkaline solutions, said time depending on number and kind of intermolecular bindings destructed during pickling. Solving of collagen in alkaline solutions depends upon nature of preliminary acidic preparing procedure. Solving is provided in aqueous solution of potassium hydroxide having concentration of 150 g/l and temperature of 18-20 C. Derma solving time is found after preliminary thermal processing at temperature of 60-65 C during 1.5 hours. Method may be employed both in production of fur and sheepskin products and in fur processing.

EFFECT: wider operational capabilities and reduced time for determining quantitative pickling characteristic of skin web.

1 tbl, 1 ex

FIELD: leather industry.

SUBSTANCE: method comprises pickling, tanning, and neutralizing the semifinished item. During pickling and subsequent tanning, the picking liquid is provided with acetate sodium in amount of 0.2-0.5 % and, then, chromic tanner in amount of 1.5-1.8%. The tanning is carried out until the pH of the solution reaches 4.2-4.4.

EFFECT: enhanced quality of tanning.

2 tbl

FIELD: defatting of crude sheepskin-and-fur material.

SUBSTANCE: method involves treating crude material in bacterial suspension having lipolytic activity of 20-30 units/g and proteolytic activity of 2.5-3.5 units/g. Suspension contains product of total microorganism vital activity used in an amount of 4-8 g/dm3, synthetic surfactant used in an amount of 0.25-0.5 g/dm3, and prokaryotic crop of Pseudomonas sp. type used in an amount of 107-109 cells/cm3, water the balance. Treatment is conducted at temperature of 40±2 C during 45 min by providing mechanical actions, and liquid coefficient of 7-10.

EFFECT: improved quality of defatting sheepskins, improved elastoplastic properties and reduced level of toxic contamination of sewage water.

3 dwg, 4 tbl

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