The method of tanning leather

 

The method applies the tanning of skins and can be used in tanneries. The hide is treated with an aqueous solution tanning with chromium compounds, in which pre-add thickener to obtain the dynamic viscosity of the composition 250-1500 MPaC. as a thickener used greasing the drug, such as "Fleece". Can also be used as a thickener to apply sagasti based on potato starch-based or algal flour. The technical result is the improvement of the technological process, quality and intensification of the process by reducing the duration of tanning. 3 C.p. f-crystals, 3 tables.

The invention relates to light industry and can be used in tanneries tanning leather.

There is a method of tanning leather, which consists in the treatment of pickling mixture of mineral oil, surfactant and solution of a tanning agent, when this processing starts when the LCD 0.4 and complete with LCD 0,0 (see patent 821489 BI 14, 1981, publ. 15.04.81).

However, this method does not allow to get wet-blue with low content of washed organic solvents and, therefore, cannot be used when s is fatty substances soft, with a slick outer surface that impedes the performance of subsequent planing.

The known method of "dry" tanning when neekelevoe the tan the hide in a small volume of liquid (about 30% by weight of the hide), containing 40-50 g/l of chromium oxide (see I. P. Fears. Chemistry and technology of leather and fur. - M: Light industry, 1979.-c.200).

However, when implementing this method, there is a danger of galls and welding surface areas of the hide due to the increase in process temperature in the friction of the walls of the drum with a small volume of liquid. In addition, the low viscosity of the working solution does not allow to apply it to the surface of the hide namesnik way, because the solution flows rapidly from the surface of the hide, and unevenly, not without being absorbed, which leads to uneven processing and loss of working solution.

There is a method of manufacture of furs, in which the tanning perform together with greasing namesnik way tanning emulsion type water in oil" for 10-30 s at the flow rate of the emulsion 150-250 g/m²and as the emulsion used, for example, a composition containing a synthetic oil, industrial oil, surfactant and liquid chromium consumption of fattening substances, which are hydrophobic environment in the emulsion of the type water-in-oil" that allows you to get a chrome semi-finished leather with a low content of washed organic solvents and, therefore, cannot be used in the manufacture of prefabricated type "Wet-blue".

The closest to the technical nature of the claimed invention is a method of tanning leather, in which the pickled hide treated with an aqueous solution of chrome tanning agent with a flow rate of tanning with chromium compounds, counting on the oxide, 2.0 to 2.5% by weight of the hide, LCD 0,7-0,8, after reaching Progresa pickling salts of chromium in the solution add neutralizing agents to improve the binding of chromium salts with functional groups of the protein (see Methods of production of leather for the uppers and lining of shoes of different thickness and range from the skins of cattle, M, 1983).

The disadvantage of this method is the high consumption of water, significant loss of tanning salts of chromium, the long duration of the process. In addition, the composition used in this method is a low viscosity that does not allow you to use it when namesno tanning due to the high turnover, leading to runoff from the surface of the hide and uneven absorption. Niemi, that increases the duration of the process.

Thus, the technical problem of the proposed method is a method of tanning leather aqueous solutions of salts of chromium with high viscosity. The technical result of the invention is the uniform application of the solution in topographic areas of the hide and uniform distribution of chromium oxide on the area, and the high viscosity of the solution does not allow it to spread, and a high concentration of chromium oxide in solution can significantly speed up the diffusion of tanning compounds in thickness of the dermis and, thus, to reduce the duration of tanning, and the solution is completely absorbed into the hide, which excludes losses tanning salts of chromium and the absence of sewage.

The proposed method of tanning leather allows you to get the chrome material with low content of washed organic solvents.

The above technical result is achieved by the fact that in the known method, which consists in the processing of the hide aqueous solutions of tanning with chromium compounds, according to the invention in aqueous solution tanning with chromium compounds add thickener in an amount of 2-10% by volume of the solution, thus obtained composition for tanning of keldara to as a thickener used greasing the drug, such as "Fleece" in the amount of 5-10% by volume of a solution of a tanning agent.

The technical result is also achieved due to the fact that as a thickener thickener used based on potato starch in the amount of 2-4% by volume solution of a tanning agent, counting on the absolute dry substance.

The technical result is also achieved by the fact that as a thickener thickener used on the basis of algal flour 2-4% by volume solution of a tanning agent, counting on the absolute dry substance.

Greasing the drug "Fleece" - an aggregating composition based on natural and synthetic products, and surfactants, resistant to acids, alkalis and electrolytes. Is a homogeneous liquid from light to dark brown color, easy to emulsify. Technical specifications (TU 249993-003-10408818-95): pH of 10% aqueous emulsion: 6-9,5.

Mass fraction of fattening substances, %: not less than 90%.

The stability of a 1% emulsion of a technical product in the electrolyte solution (min): not less than 30.

The stability of a 10% emulsion of a technical product in the electrolyte solution (min): not less than 30.

In table. 1 presents data on the impact of fattening to preparate for these compounds was not determined, because they lacked the fluidity and therefore could not flow through the gauge hole viscometer).

From table. 1 shows that the optimal number of fattening drug "Fleece" is 4-10%, preferably 5-10% to obtain stable results. Further increase in the content of the drug "Fleece" in the impractical despite the high viscosity, because it leads to increase in the content of washed organic solvents in the skin and, therefore, the composition cannot be used to obtain semi-finished type "Wet-blue". In addition, it was observed osalennosti the front surface of the semi-finished product after tanning.

In table. 2 shows the effect of the concentration of thickener in an aqueous solution of chrome tanning agent containing chromium oxide 150 g/l relative and dynamic viscosity of the composition and results of the research process namanga tanning compositions obtained. Thickeners was previously prepared and dosed out in a solution of a tanning agent. For example, mass of absolutely dry matter of sagasti based on starch accounted for 48.9%, based on the algal flour - 39,6%. 100 ml of an aqueous solution of a tanning agent at a flow rate of thickener based on starch 2% of the volume restos.

On the pickled hide inflicted the analyzed compounds and determined the time required to complete Progresa dermis thickness pickling salts of chromium. After processing and aging was determined temperature welding of chrome-plated semi-finished product. When the anointing of the composition to the surface of the hide watched distribution on the surface of the hide.

From table. 2 shows that the optimal amount of solution of thickener, based on the starch in the solution of chrome tanning agent is 2-4% of the tanning agent, counting on a dry residue. While the dynamic viscosity equal 725-1023 MPawith that viscosity is 1.75 to 2.6. The optimal amount of solution of a thickener based on the algal flour is 2-4%, counting on a dry residue. While the dynamic viscosity equal 935 - 1527 MPaC, viscosity - 2,53-3.7V. In other cases, there has been uneven distribution of working on topographic areas and thickness of the hide.

Tanning tanning solution with high viscosity can be namesnik way to manually brush or namazee machine or dryer.

Comparison of proposed method with other well-known from the prior art technical solutions allowed the declare.

The proposed method of tanning leather is as follows.

In an aqueous solution of chrome tanning agent containing chromium oxide 100-150 g/l, the basicity of 38-42% add thickener, such as "Fleece" in the amount of 5-10% by volume of a solution of a tanning agent or as a thickener may be used sagasti used in the textile industry, for example, potato starch or algal flour in amounts of 2-4% by volume solution of a tanning agent, counting on dry substance, mixed and the resulting composition is applied to the pickled hide from the face and bahramani parties from the calculation of 2-4 g/DM².

Dynamic viscosity of the composition 250-1500 MPaC. To accelerate the penetration of salts of chromium in thickness of the dermis solution manually rubbing with a brush, or namazee machine or dryer. After 1.5-2 hours from the beginning of the process there is a complete paint over the dermis salts of chromium, temperature welding of prefabricated 102-109^oC.

Examples confirming the implementation of the method.

Example 1. On the pickled hide from the face and bahramani parties put pre-cooked tanning solution with a dynamic viscosity of 400 MPawith the number 3 XID chromium 150 g/l, the basicity of 40% with the thickener - feeding drug "Fleece" in the amount of 5% by volume solution of a tanning agent, with the dynamic viscosity tanning composition is equal to 320 MPaC.

Tanning composition is rubbed with a brush, at the same time paint the cut was 1.5 hours and the temperature of the welding 102^oWith the content of washed organic solvents 2%.

When applying tanning composition is well absorbed, not draining from the surface of the semifinished product.

Example 2. The hide after pickling is not unloaded from the suspended drum is reinforced, pikelny solution was decanted and the hide through the hollow shaft during the rotation filed tanning composition in the amount of 30% by weight Zelenogo pickling, pre prepared by mixing an aqueous solution of chrome tanning agent with a concentration of chromium oxide 120 g/l, the basicity of 40% with the thickener - feeding drug "Fleece" in the amount of 5% by volume of a solution with the following parameters: a temperature of 25^oWith, the consumption of chromium compounds, counting on the oxide and 2.5% by weight Zelenogo of the hide. While the dynamic viscosity tanning solution equal to 300 MPaC. After 30-40 minutes from the beginning of the process the solution is completely absorbed Golem. After 50 minutes from the beginning is a prevalence of 1.9%, wastewater is missing.

Example 3. On the pickled hide from the face and bahramani parties have caused pre-cooked tanning composition with a dynamic viscosity of 1000 MPawith the amount of 3 g/DM³. Tanning composition when applied is not flowed to the surface.

Tanning composition is prepared by mixing an aqueous solution of a tanning agent (the concentration of chromium oxide 150 g/l) with a thickener containing wt. including: potato starch - 150, 35% hydrochloric acid - 1,4, sodium acetate and 1.5, water - 847,1. The amount of thickener in the solution of chrome tanning agent is 3%, counting on dry substance, or 30% solution of the thickener of the volume of the solution of the tanning agent.

After three hours from the beginning of the process temperature welding of prefabricated 90^oC, the contents washed out with an organic solvent to 1.3%. Tanning composition is fully absorbed into the hide, the wastewater is missing.

Example 4. On the pickled hide from the face and bahramani parties put pre-cooked tanning solution with a dynamic viscosity of 900 MPawith the amount of 3 g/DM². Tanning composition when applied to the surface does not spread.

Tanning composition was prepared by SMEs.%: algal flour 60, acetic acid (80%) - 10, water - 100.

The amount of thickener in the solution of chrome tanning agent is 5%, counting on the absolute dry substance. After 3 hours from the beginning of the process the temperature of the welding 90^oC, the contents washed out with an organic solvent to 1.2%. Tanning composition is fully absorbed into the hide, the wastewater is missing.

The proposed method of tanning leather was applied in the semiindustrial conditions.

For tests used a composition containing an aqueous solution of chrome tanning agent with a concentration of chromium oxide 150 g/l, basicity - 40%, greasing the drug "Fleece" in the amount of 5%. Dynamic viscosity tanning composition is 320 MPaC. All processes and operations, including pickling, were conducted by the method of tanning leather upper and lining shoes of different thickness and range from the skins of cattle. After the pickling pickling unloaded, allowed to drain from the surface. Cooked tanning composition was applied with a brush on the face and boterman hand at the rate of 2 and 3 g/DM².

In the control variant (prototype) used tanning composition containing solution of chrome tanning agent with a concentration of chromium oxide 50 g/l, the basicity of 40%.

Process control is La top and lining of shoes of different thickness and range from the skins of cattle, M., 1985).

In the process of testing observed uniformity of absorption of tanning composition on the topographic plots of the hide, was determined by the temperature of the joining material, the content of chromium oxide and washed with organic solvents was determined by the content of chromium oxide in the spent solution.

The results of the tests are presented in table.3.

Thus, the proposed method of tanning enables you to evenly apply tanning composition namesnik way to the surface of the hide. Thus the solution due to the increased viscosity does not flow from the surface. A small amount of added sagasti in the form of fattening preparations from 5-10% allows you to use the proposed method to obtain a semi-product with low content of washed organic solvents.

The performance properties of chrome-plated semi-finished product meet the requirements of the prefabricated type "Wet-blue". Compared with the prototype tanning according to the invention, the waste water is absent and, therefore, eliminates the discharge of chromium salts.

Claims

1. The method of tanning leather, which consists in the processing of the hide aqueous solutions of tanning compounds, HRO is the solution the obtained composition for tanning has a dynamic viscosity of 250-1500 MPaC.

2. The method according to p. 1, characterized in that the thickener used greasing the drug, for example, "Fleece" in the amount of 5-10% of the volume of the solution.

3. The method according to p. 1, characterized in that the thickener used sagasti based on potato starch 2-4% of the volume of the solution, considering the dry substance.

4. The method according to p. 1, characterized in that the thickener used sagasti on the basis of algal flour 2-4% of the volume of the solution, considering the dry substance.