SU1141114A1 - Method of processing hides - Google Patents

Abstract

1. METHOD FOR TREATING LEATHER, which includes pickling a mole in the presence of an additive that activates tanning, and subsequent chrome tanning in the presence of an alkaline reagent, characterized in that, in order to improve the quality of leather, reduce the consumption of tanning agents and pollute sewage during tanning, As an alkaline reagent, a mixture of sodium silicate and calcium dihydroxide is used at a consumption of 0.2-0.4%, respectively (based on silica) and 0.2-0.5% by weight of a mole, and an additive that activates tanning is introduced in the amount of 0.2-0.4% by weight of the mole. 2. A method according to claim 1, characterized in that phthalic acid or sodium polyphosphate is used as an additive in activating tanning. 3. The method according to claim 1, characterized in that chrome tanning is carried out with a tanning rate of 1.4-1.8% with a basicity of 33-40%. ,

Description

The invention relates to light industry and can be used in tanning leather for upper shoes, haberdashery and other products. A method of treating leather is known, according to which, after pickelling with a mixture of sodium chloride j of formic and sulfuric acid, acacia doublelt, two types of chrome tanning, one of which has a 33% basis of 0.7%, and another, introduced after 1 hour of tanning form of the self-alkaline preparation, - 0.8% CZiOj. 1.6 mol of dicarboxylic acid per mole, rotation time 7.5 h, pH n end of 3.9, bath temperature AOC ft. are added simultaneously. The disadvantages of this method are the necessity of using specially synthesized self-alkalizing chrome tanning; the consumption of a large amount of dicarboxylic acids (2.6% of the mass of a mole), along with the use of muracic acid during pickling. The large amount of dicarboxylic acid introduced into the tanning bath is not only economically disadvantageous for the required activation of chrome tanning, but leads to an increase in the concentration of dicarboic acid in the spent bath to contamination of wastewater. Also known is a method of treating leather by chrome tanning using adipic acid in combination with zeolites 2. The disadvantage of this method is the use of defensive materials. The closest in technical essence and the achieved effect to the proposed one is a method of treating leather, including pickling a cannon in the presence of formic or phthalic acids at a consumption of acid of 0.5-1.0%, tanning at a consumption of chrome tanning with basicity of 38-42% equal to 1.8-2.4% with the introduction of magnesium compounds into the tanning bath, while magnesia is used as magnesium compounds in quantities of 054-058% by weight of mol per tia magnesium oxide 3, - The disadvantages of the known method are high salt content chromium (up to 18%) tannom rast42 thief; the increased consumption of phthalic acid, which, taking into account its low solubility in water, contributes to the accumulation of acidic potholes in an undissolved state and leads to its loss and distortion of the parameters of pickling and tanning; the use of scarce material - magnesia. The purpose of the invention is to improve the quality of leather, reducing the consumption of tanning agents and polluted sewage. This goal is achieved due to the fact that according to the leather treatment method, including pickling a mole in the presence of an additive that activates tanning, and subsequent chrome tanning in the presence of an alkaline reagent, when tanning, a mixture of sodium silicate and calcium dihydroxide is used as an alkaline reagent, respectively, 0 , 2-0.4% (based on silica) and 0.2-0.5% by weight of the mole, and the tanning additive activating is introduced in an amount of 0.20, 4% by weight of the mole. At the same time, as an additive activating tanning, polystyrene jthiol phthalic acid or polysodium phosphate is used. Chrome tanning is carried out with a tanning rate of 1.4-1.8% with a basicity of 33-40%. A feature of the method is the combined activation of chrome tanning by introducing with pickling a limited amount of ph. Of peic acid or sodium polyphosphate and the subsequent addition of sodium silicate and calcium dihydroxide. Sodium silicate (GOST 917-41 and 4420-48) is used in an amount (0.2-0.4% Si Oj), which intensifies the fixation of chromium compounds with a semifinished product by increasing the basicity of chromium salts in the solution, and by forming chromosilicate compounds , acting on collagen as an active filler, contributing to the elimination of skin friability and stifling. The specified amount of sodium silicate, associated with shit collagen, does not reduce the strength of the skin and does not result in stiffening. Calcium dihydroxide contributes to the regulation of the basicity and pH of the effluent at a level corresponding to a more complete absorption and fixation of chromium compounds by the semi-finished product, thus excluding the possibility of the formation of chromium carbonate complexes and the release of carbon dioxide both inside the semi-finished product and in the solution. Example 1. A light weight of 20 kg is taken after duplicating a thickness of 2.5 mm. The dosage of the material is taken in% by weight of the mole after the double. All operations before washing after softening are carried out before the current procedure, Pickling: W 0.6; t 20 С; , MA 4.5% j 0.7%; phthalic anhydride 0.2%; duration 1.5 hours; The pH of the spent pickel is 3.0-3.4; density 1,027-1,035; acid content per HjS 0.5-0.7 g / l. Tanning: chromic tanning with a basicity of 40% in the amount of 1.4% is introduced into the spent pical liquid, after 1.0-1.5 hours, the paint is stained and, when the barab is rotated, it is diluted with water (t-AIA) in a ratio of 1 : 2 solution of sodium silicate in the amount of 0.4% 6, black for 1.0-1.5 h. Injects dihydroxy calcium in the amount of 0.3% CaOHON into the bath). After 3 hours tanning, the temperature of skin welding is checked, which should be not lower than 90 ° C. The pH of the used juices is 3.8-4.2, the concentration of chromium salts is 0.6-0.9 g / l. Example 2. Take away beads with a light weight of 20 kg after dividing to a thickness of 3.0 mm. The dosage of the materials is taken in% by weight of the mole after the double. Rinsing, desalting, softening, rinsing - according to the current method. Pickling: LCD 0.6; t 20 ° C; NaC6 3.5%; 0.9%; sodium polyphosphate 0.3%; duration 2 hours; The pH of the spent pickel is 2.9-3.2, the density is 1.030-1.040, 0 0.60, 9 g / l. Tanning: a chromium tanning agent with a basic content of 33% in the amount of 1.6% is injected into the spent pical liquid in 1.5 hours, the paint is stained and, while rotating the bar 14-4 ban, the sodium silicate solution is diluted with water in a ratio of 1: 2, 3% S 0, after 1 h, calcium dihydroxide is added to the bath in the amount of 0.4% CaOH). After 3 hours of tanning, the skin welding temperature should not be lower than 90 ° C, the pH of the solution should be 3.8-4.2, the concentration of chromium compounds in the bath should not exceed 0.9 g / l. Example 3. Take beef goatsina light weight of 20 kg. The doubles in the hem is not produced. The dosage of the materials is taken as a percentage of the mass of the twin warhead. Littering, desalting, grinding, rinsing - according to the current method for non-batchless. Whether kelivanie: LCD 0.7; t Ma Cl 67; 1.2%; phthalic anhydride 0.4%; duration 3 hours, the pH of the spent pickel 2.8-3.0; the density is 1,030-1,040, the content is 0.7-1.0 g / l. . Tanning: a chromic tanning agent with a basicity of 40% in the amount of 1.8% based on chromium oxide is introduced into the spent pical liquid. After 3-4 hours, the proration of chromium salts was checked, and as the drum rotated, a solution of sodium silicate diluted with water (t 20 ° C) in a ratio of 1: 2 in an amount of 0.2% Si 0 was introduced and after 2 hours calcium dihydroxide in the amount of 0.5% Ca (OH). After 4 h, the temperature of skin welding should not be below 95 ° C; The pH of the solution is 3.8-4.2j, the concentration of chromium compounds is not more than 1.2 g / l. Indicators of the properties of leather, vdudublen-. data in examples 1-3, the characteristics of the spent tanning solution and developed leather are presented in Table. t and 2. The use of phthalic acid in the form of phthalic anhydride, sodium silicate and calcium digoxide to activate chrome tanning accelerates tanning, resulting in a semi-finished product with a smooth, unstressed front surface, improving the quality of the skin, and increasing the selection of the semi-finished product for the production of elastic facial skin.

Table 1

Stress at occurrence of front layer cracks, 10 MPa

Elongation,% 0, 20 0.18 0.22

we are 9,58,70 9,42

to

444

ki,

420 390. 450 174 200 187

1.82

1,761, 93

0.24

9.11

410 170 The concentration of chromium oxide in the treated bath, g / l 0.82 1.24 The content of chromium compounds in the skin per oxide 4.41 4.68 4.92 chromium,% The number of developed leather of improved quality,% Grade of finished leather,% Raw material consumption per 100 m of finished leather, kg

table 2

Claims (3)

1. METHOD OF SKIN TREATMENT, including pickling of a pin in the presence of an additive that activates tanning, and subsequent chrome tanning in the presence of an alkaline reagent, characterized in that, in order to improve the quality of leathers, reduce tanning consumption and wastewater contamination, when tanning as alkaline the reagent use a mixture of sodium silicate and calcium dihydroxide at a flow rate of 0.2-0.4%, respectively (based on silicon oxide) and 0.2-0.5% by weight of the gol, and the tanning activating additive is introduced in an amount of 0 , 2-0.4% of the mass of the goal. 2. The method according to p. 1, characterized in that as an additive that activates tanning, use phthalic acid or sodium polyphosphate. 3. The method according to p. ^ Characterized in that the chrome tanning is carried out at a tanning rate of 1.4-1.8% with a basicity of 33-40%. ttttgg 1 11