RU2601292C1 - Method of drumming leather - Google Patents

Abstract

FIELD: leather industry.

SUBSTANCE: invention relates to leather industry in production of leather of various assortment, in particular, to methods of drumming leather in presence of fungicide, and can be used in skin processing for improving operational properties. Method of drumming leather is implemented with drumming composition in presence of an effective antifungal inhibitor, the latter is represented by 6.0 % solution of N¹-chloro-methylbenzimidazole fungicide. Fungicide is dissolved in ethyl alcohol taken in the amount of 0.2-0.5 % of squeezed leather weight at the drumming composition consumption of 20-22 % of the squeezed leather weight in terms of 100 % fat. Drumming time is 1.5-2.5 hours at the temperature of 70-80 °C.

EFFECT: proposed method of drumming leather provides effective antifungal inhibition at high quality of finished skin.

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Description

The invention relates to the leather industry in the production of leathers of various assortments, in particular to a method of fatliquoring leather in the presence of a fungicide, and can be used in the treatment of leather to improve its operational properties.

A known method of fatliquoring yufti in the presence of a fungicide in which a 10-12% solution of 4,5,6-trichlorobenzoxazolinone-2 in dimethylformamide in an amount of 1.5-2.5% by weight of pressed leather is used [Copyright certificate SU 1341201, IPC C14C 9/02, 1987].

However, the fungicide used has unstable mobile chlorine atoms, which, when interacting with fats, migrate and eventually disappear.

The closest in technical essence and the achieved result to the claimed invention is a method of fatliquoring of leathers, in which to improve the performance properties of the skin, a 3-5% solution of 6-chloro, 2-oxo, 3-benzoxazolylmethylmethacrylate in acetone is used in the amount of 0.3-0.7% by weight of pressed leathers [Patent UZ IAP 02945, IPC С14С 9/02, 2003].

The disadvantage of this method is the instability of the composition over time, reducing the effect of anti-mold inhibition, deterioration of the appearance and quality of the finished skin.

The objective of the invention is to create a more effective method of fatliquoring in the presence of fungicide and its economical use.

The technical result is an increase in the effect of anti-mold inhibition, improving the quality of the finished skin.

The technical result is achieved by the fact that in the method of fatliquoring the skin, including treating it with a fatliquoring composition in the presence of a fungicide according to the invention, a 6.0% solution of N ¹ -chloromethylbenzimidazole is used as a fungicide, which is dissolved in ethyl alcohol taken in an amount of 0 , 2-0.5% by weight of pressed leathers, at a consumption of the fatliquoring composition 20-22% by weight of pressed leathers, calculated on 100% fat, fatliquoring time 1.5-2.5 hours, and at a temperature of 70-80 ° C.

Carrying out the process of fatliquoring for less than 1.5 hours does not allow to achieve the declared result, i.e. the fatliquoring composition is not sufficiently absorbed by the dermis, and with an increase in the fatliquoring duration of more than 2.5 hours, the fatliquoring composition is fully worked out and does not significantly affect the organoleptic properties of the fatty semi-finished product.

A significant difference of the proposed method is the good solubility of the fungicide, which is used as a 6.0% solution of N ¹ -chloro-methylbenzimidazole, which is dissolved in ethanol, and taken in an amount of 0.2-0.5% by weight of pressed leather, which allows to increase the effect of anti-mold inhibition, to improve the quality of the finished skin and to spend fungicide economically, since its intensive and rapid penetration into the skin thickness is ensured at low concentrations. A decrease in the fungicide concentration in the fatliquoring composition below 0.2% reduces the effect of anti-mold inhibition, and with an increase in the fungicide consumption of more than 0.5% in the fatliquoring composition, the effect of anti-mold inhibition remains almost unchanged.

Also, a significant difference of the claimed method is to reduce the consumption of the fatliquoring composition to 20-22% by weight of pressed skin, calculated on 100% fat due to the use of a 6.0% solution of N ¹ -chloro-methylbenzimidazole dissolved in ethyl alcohol, which allows you to intensively and quickly penetrate the fatliquoring composition containing this fungicide in the skin structure, improving its performance properties. With the consumption of the fatliquoring composition less than 20% of the weight of pressed leathers, the finished skin becomes fragile, tough and dry. When the consumption of the fatliquoring composition is more than 22%, it leads to an overuse of components. Also, in the facial surface of the skin, there is a salinity without an increase in the amount of chemically bound fatty substances in the skin structure.

To obtain N ¹ -chloro-methylbenzimidazole, N ¹ -hydroxymethylbenzimidazole is synthesized [Akbarova CP, T. Kodirov, A. Yu. Toshev. Synthesis and study of the fungicidal properties of benzimidazole-based heterocyclic systems for natural leathers / Materials of the Republican Scientific and Practical Conference. "Development and improvement of the design and technology of leather products." - Tashkent: 2008, 1 volume, p. 7-10].

The reaction of obtaining a new compound N ¹ -hydroxymethylbenzimidazole is carried out according to the scheme:

For this, 2 kg of chemically pure benzimidazole is weighed and recrystallized several times with hot water in the presence of activated carbon. Then, 1.5 kg of benzimidazole is dissolved in boiled water for 1.5 hours. To the solution, 1.0 dm ^{3 of a} 35% formalin solution was slowly added portionwise and allowed to hydroxymethylate benzimidazole. The precipitate of N ¹ -hydroxymethylbenzimidazole formed is filtered off and washed several times with chilled water and dried in air. The yield of the target product is 72-79%.

The next stage of the chlorination reaction of N ¹ -hydroxymethylbenzimidazole is carried out according to the following scheme:

The chlorination of N ¹ -hydroxymethylbenzimidazole is carried out according to the procedure [Zinner N., Herbert N., Wert N. Mannich-Basen des Benzoxazolons. Chem. Beer. 1956. Bd. 89. P. 2131-2135. Kadirow TD, Ruziew RR, Yariew OM Synthese, Strukturuntersung und Eigenschaften eines neuen Fungisids zur Schimmel-Schutz-Ausrüstung von Ledern. Journal "Leder und Häutemarkt", Germany, 2002, N 10. - P. 40-42.].

To 0.495 kg of finely ground N ^1- hydroxymethylbenzimidazole, a 45% hydrochloric acid solution was slowly poured and stirred, then heated for 10 minutes. The resulting mass is filtered off, washed with cold water to a neutral environment. The yield of N ¹ -chloro-methylbenzimidazole is 0.5 kg (82%).

The essence of the invention lies in the fact that the treatment of the skin with a fatliquoring composition is carried out in the presence of an effective anti-mold inhibitor (fungicide), which is used as a 6.0% solution of N ¹ -chloro-methylbenzimidazole, which is dissolved in ethyl alcohol, taken in an amount of 0 , 2-0.5% by weight of pressed leather. The fatliquoring of the skins proposed in the prototype is carried out in the presence of the fungicide 6-chloro, 2-oxo, 3-benzoxazolylmethyl methacrylate. The effect of anti-mold inhibition of the fungicides proposed in the claimed invention and in the prototype is evaluated by the inhibition of the growth of microscopic fungi.

To assess the effect of anti-mold inhibition, Aspergillus niger, Aspergillus fumigates, Fusarium sporotrichiella, which are grown on a Boden-Gaultier synthetic glucose-peptone medium, are used. The test results of fungicides are shown in table 1.

From table 1 it is seen that the 6.0% solution of N ¹ -chloro-methylbenzimidazole at a concentration of 2-4 mg has a pronounced antibacterial activity, which is confirmed by the formation of a zone of growth inhibition of fungi with a radius of 16-21 mm compared to the prototype 15-19 mm

A 6.0% solution of N ¹ -chloro-methylbenzimidazole is prepared as follows. The required amount of ethyl alcohol and the calculated amount of N ¹ -chloro-methylbenzimidazole taken in an amount of 0.2-0.5% by weight of pressed leather are poured into a reactor equipped with a mechanical stirrer. After its complete dissolution in ethanol is used in the process of fatliquoring the skin.

The method of fatliquoring of the skin is as follows. Before fatliquoring, a fatliquoring composition is prepared by mixing a 6.0% solution of N ¹ -chloro-methylbenzimidazole, which is dissolved in ethanol at a rate of 0.2-0.5% by weight of wrung-out leathers and a fatliquoring composition of 20-22% by weight of wrung-out skins in terms of 100% fat. Fatliquoring composition includes: soap stock - 30 wt. %, distilled fatty acids - 20 wt. %, spindle oil - 20 wt. %, heavy fat - 15 wt. %, technical fat - 10 wt. %, paraffin - 5 wt. % Duration of fatliquoring is 1.5-2.5 hours. The tanned semi-finished product, squeezed to a moisture content of not more than 40%, is loaded into a heated drum, in which the temperature of the incoming air 70-75 ° C, leaving 35-40 ° C, is rotated without a fatliquoring composition for 40 minutes. After that, the previously prepared fatliquoring composition is poured into the drum, heated to 70-80 ° C in three doses with an interval of 10 minutes in equal proportions for uniform penetration of the fatliquoring composition into the skin structure. The dosage of the fatliquoring composition in three doses with an interval of 10 min provides a more uniform homogeneous adsorption of the fatliquoring composition and its uniform distribution in the structure of the semi-finished product.

Examples confirming the implementation of the method of fatliquoring of the skin using an effective anti-mold inhibitor (fungicide) - 6.0% solution of N ¹ -chloro-methylbenzimidazole.

Example 1

Semi-finished leather product, squeezed to a moisture content of 40%, processed according to the standard method [Typical method for the production of shoe and saddlery yuft chrome sintanotannid tanning from cattle and horse hides for civilian products (Developed by TsNIIKP). - M.: TSNIITEIlegprom, 1985.], from the raw material of the heavy chrome sintanotannid tanning raw material with the fatliquoring composition of the following composition: soap stock - 30 wt. %, distilled fatty acids - 20 wt. %, spindle oil - 20 wt. %, heavy fat - 15 wt. %, technical fat - 10 wt. %, paraffin - 5 wt. % The consumption of the fatliquoring composition is 20% by weight of pressed leather, calculated on 100% fat, 6.0% solution of N ¹ -chloro-methylbenzimidazole dissolved in ethyl alcohol, 0.2% by weight of pressed leather. Furthermore, temperature of treatment is 70 ° C, duration of fatliquoring is 2.5 hours.

The resulting semi-finished product is characterized by softness, delicate neck, lack of screed and greasy. The percentage of damage to skin samples with a mixture of molds obtained in this embodiment was 0.2%.

Example 2

Carried out in the same way as in example 1, only the consumption of the fatliquoring composition was taken 21% of the weight of pressed skin in terms of 100% fat, 6.0% solution of N ¹ -chloro-methylbenzimidazole dissolved in ethyl alcohol, 0.35 % by weight of pressed leather, while the processing temperature is 75 ° C, the duration of fatliquoring is 2.0 hours.

The resulting semi-finished product is characterized by softness, delicate neck, lack of screed and greasy. The percentage of damage to skin samples with a mixture of molds obtained in this embodiment was 0.1%.

Example 3

Carried out in the same way as in example 1, only the consumption of the fatliquoring composition was taken 22% by weight of pressed skin, calculated on 100% fat, a 6.0% solution of N ¹ -chloromethylbenzimidazole dissolved in ethyl alcohol, 0.5 % by weight of pressed leather, while the processing temperature is 80 ° C, the duration of fatliquoring is 1.5 hours.

The resulting semi-finished product is characterized by softness, delicate neck, lack of screed and greasy. The percentage of damage to skin samples with a mixture of molds obtained in this embodiment was 0.0%.

As can be seen from the above examples 1-3, the optimal fatliquoring parameters are: the consumption of the fatliquoring composition is 20-22% by weight of pressed skin, calculated on 100% fat, the use of a 6.0% solution of N ¹ -chloromethylbenzimidazole, dissolved in ethanol is 0.2-0.5% by weight of pressed leather, the processing temperature is 70-80 ° C, the duration of the fatliquoring is 1.5-2.5 hours.

In the inventive method, the fatliquoring of the skin is carried out for 1.5-2.5 hours, with a consumption of the fatliquoring composition of 20-22% by weight of pressed skin, calculated on 100% fat, using an effective anti-mold inhibitor - fungicide, which is used as 6.0% solution of N ¹ -chloro-methylbenzimidazole dissolved in ethyl alcohol in an amount of 0.2-0.5% by weight of pressed leather. Whereas in the prototype fatliquoring is carried out for 3 hours using a 24% fat composition, using 6-chloro, 2-oxo, 3-benzoxazolylmethyl methacrylate as a fungicide in an amount of 0.7% by weight of pressed leather. Therefore, the claimed method of fatliquoring of the skin is more efficient and economical, allowing to reduce the consumption of fungicide from 0.7% to 0.2-0.5% and the fatliquoring composition from 24% to 20-22% of the weight of pressed leather, which allows to increase the effect anti-mold inhibition and to obtain the target product with improved performance of the finished skin due to the use of a 6.0% solution of N ¹ -chloro-methylbenzimidazole dissolved in ethyl alcohol as a fungicide.

Table 2 presents the physico-chemical, mechanical and mold-resistant characteristics of the treated leather in comparison with the prototype.

As can be seen from the data in table 2, the finished skin treated with a 6.0% solution of N ¹ -chloro-methylbenzimidazole during the fatliquoring process is characterized by softness, delicate neck, lack of screed and greasy.

It should be noted that the indicators of table 2, which indicates that the percentage of damage to skin samples with a mixture of molds obtained by the prototype, amounted to 0.6%, whereas for leathers processed by the technology of the proposed method, from 0.0 to 0 , 2%.

Thus, a more effective method of fatliquoring is proposed, including treating the skin with a coating composition consisting of soap stock - 30 wt. %, distilled fatty acids - 20 wt. %, spindle oil - 20 wt. %, brain fat - 15 wt. %, technical fat - 10 wt. %, paraffin - 5 wt. % in the presence of a mold inhibitor of a 6.0% solution of N ¹ -chloro-methylbenzimidazole soluble in ethanol taken in an amount of 0.2-0.5% by weight of wrung out leathers with a consumption of fatliquoring composition of 20-22% by weight of wrung out leathers in terms of 100% fat, fatliquoring time of 1.5-2.5 hours and a treatment temperature of 70-80 ° C, which allows to increase the effect of anti-mold inhibition and thereby improve the physicochemical and mechanical properties of the finished skin.

The proposed method of fatliquoring of leathers in comparison with the prototype (patent UZ IAP 02945, IPC СС 9/02, 2003) allows to obtain the following advantages:

- reduce the consumption of fungicide from 0.7% to 0.2-0.5% by weight of pressed leather;

- reduce the consumption of fatliquoring composition from 24% to 20-22% by weight of pressed leather in terms of 100% fat;

- to increase the effect of anti-mold inhibition, as evidenced by a decrease in the percentage of damage to skin samples with a mixture of molds from 0.6% (according to the prototype) to 0.2-0.0% due to the use of a 6.0% solution of N ¹ as a fungicide - chloro-methylbenzimidazole dissolved in ethyl alcohol;

- improve the quality of the finished skin by increasing the effect of anti-mold inhibition.

Claims (1)

A method of fatliquoring the skin, including treating it with a fatliquoring composition in the presence of a fungicide, characterized in that a 6.0% solution of N ¹ -chloro-methylbenzimidazole is used as a fungicide, which is dissolved in ethyl alcohol taken in an amount of 0.2-0, 5% by weight of pressed leathers, at a consumption of the fatliquoring composition 20-22% by weight of pressed leathers, calculated on 100% fat, fatliquoring time of 1.5-2.5 hours and a temperature of 70-80 ° C.