LT4097B - Method for manufacturing of hides - Google Patents

Abstract

Invention belongs to light industry and may be used to produce tanned leather. The described bald skin production method is implemented during two stages - A and B, having carried out stage B in the solution obtained during stage A. (The quantities of substances are given as a % of the total leather raw material mass.):Stage A: - the coefficient of the liquid is 0.6; the temperature is 23-25 degrees Centigrade; the duration of process is 3 hours; the quantity of NaOH is from 2 to .3 %; Na2HPO4 is from 1.5 to 2.0 %; Na2S is from 0.55 to 0.65 %; the working conditions are continuous mixing.B stage: the coefficient of liquid is increased to 1.0; the temperature is 20-25 degrees Centigrade; the duration is from 9 to 13 hours; the quantity of Na2HPO4 is from 1.5 to 2.0 %; the working conditions are continuous mixing for 1 hour then leaving to rest.By this bald skin production method, the quality of hair destruction is improved and the destruction of collagen albumin is lower, and, at the same time, the quality of bald skin and ready-to-use tanned leather is improved.

Description

The invention relates to the light industry and can be used in the preparation of hides and skins.

There is a known method of obtaining baldness, wherein the treatment of the skins is carried out at a liquid coefficient (number of times) of 0.3-0.8 with a solution consisting of (%);

sodium sulfide 0.8-2.5, sodium caustic 0.5-2.0, water 30-50, emulsifier 0.5-2.0, hydrophobic solvent - the rest (see former USSR aut. witness No. 825639, TPC C14C 1/06, 1981).

This method consumes large amounts of a hydrophobic solvent, which is relatively expensive and requires sophisticated apparatus to regenerate it. In addition, the solvent would evaporate and pollute the process during the process.

The closest solution to the proposed solution is the method of obtaining the bald, which is obtained in two steps A and B, the latter being carried out in a solution of stage A (quantities of substances are given in% by weight of the raw material of skins)

Stage A - incl. - 0.3, temperature -25-28 ° C, duration 3 hours, Na ₂ SO ₄ aqueous solution (100 g / l) - 20%, NaOH aqueous solution (50% -is) 10%, mode - stir continuously.

Stage B. See increase to 1.5, temperature -25-28 ° C, duration 9-13 h, Na ₂ SO ₄ aqueous solution (100 g / l) - 130%, mode - 1 h. mix continuously, then leave at rest (see VFR Patent No. 2714813, TPK C14C 1/00, 1979).

This method does not produce high quality hair breakage, severely destroys collagen proteins during the process, resulting in degraded bat quality.

The object of the invention is to improve the quality of the finished bat by improving the quality of hair coat breakdown, reducing collagen protein degradation and reducing chemical consumption.

This purpose is achieved by the two stages A and B of the balding process, the latter being carried out in a solution of stage A (the amounts of substances are given in% by weight of the raw material of the skins):

Stage A - incl. - 0.6, temperature 23-25 ° C, duration 3 hours, NaOH 2-3%, Na ₂ HPO ₄ - 1.5-2.0%, Na ₂ S - 0.55-0.65 %, mode - mix continuously.

Stage B - incl. increase to 1.0, temperature 23-25 ° C, duration 9-13 hours, Na ₂ HPO ₄ -1.5-2.0%, mode 1 hour. stirring continuously, then leaving at rest.

This method of balding improves the quality of hair breakdown, reduces collagen protein breakdown, while improving the quality of the bald and the finished bat.

Specific examples of the proposed method of balding:

Fig. After soaking, the raw material of leather shall be treated in accordance with the following procedure:

Stage A - incl. - 0.6, temperature - 25 ° C, duration - 3 hours, NaOH -1%, Na ₂ HPO ₄ - 3%, Na ₂ S - 0.55%, mode - stir continuously.

Step B is carried out in the solution of Step A. See increase to 1.0, temperature 25 ° C, duration 13 hours, Na ₂ HPO ₄ - 2.0%, mode 1 hour. stirring continuously, then leaving at rest.

Fig. After soaking, the raw material of leather shall be treated in accordance with the following procedure:

Stage A - incl. 0.6, temperature 25 ° C, duration 3 hours, NaOH 2%,

Na ₂ HPO ₄ -1.5%, Na ₂ S 0.6%, mode - continuous stirring.

Step B is carried out in the solution of Step A. See increase to 1.0, temperature 25 ° C, duration 13 hours, Na ₂ HPO ₄ - 1.5%, mode 1 hour. stirring continuously, then leaving at rest.

Fig. After soaking, the raw material of leather shall be treated in accordance with the following procedure:

Stage A - incl. - 0.6, temperature - 25 ° C, duration - 3 hours, NaOH 2.5%, Na ₂ HPO ₄ - 2%, Na ₂ S - 0.6%, mode - stir continuously.

Step B is carried out in the solution of Step A. See increase to 1.0, temperature 25 ° C, duration 13 hours, Na ₂ HPO ₄ - 2%, mode 1 hour. stirring continuously, then leaving at rest.

Fig. After soaking, the raw material of leather shall be treated in accordance with the following procedure:

Stage A - incl. 0.6, temperature 23 ° C, duration 3 hours, NaOH 3%,

Na ₂ HPO ₄ - 2%, Na ₂ S - 0.55%, mode - stir continuously.

Step B is carried out in the solution of Step A. See increase to 1.0, temperature - 23 ° C, duration - 9 hours, Na ₂ HPO ₄ - 2%, mode - 1 hour. stirring continuously, then leaving at rest.

Fig. After soaking, the raw material of leather shall be treated in accordance with the following procedure:

Stage A - incl. - 0.6, temperature - 23 ° C, duration 3 hours, NaOH - 4%, Na ₂ HPO ₄ -1%, Na ₂ S - 0.6%, mode - stir continuously.

Step B is carried out in the solution of Step A. See increase to 1.0, temperature - 23 ° C, duration - 9 hours, Na ₂ HPO ₄ - 1%, mode - 1 hour. stirring continuously, then leaving at rest.

The known method and the variants of the proposed method have shown the baldness and its qualitative indices were determined: disruption of the hair coating and destruction of collagenous proteins.

The quality of the breakage of the hair coat was evaluated organoleptically, according to the relative scoring system: 0 - the hair is intact, 1 - the hair is trimmed, 2 the hair coat is broken but not removed from the upper layer, 3 the upper layer is clean.

The degradation of collagen proteins was evaluated by the amount of oxyproline in the treatment solutions. The results of the hair coat and collagen breakdown determination are shown in the table.

Table

Results of the determination of hair coat and collagen protein degradation

Indicator Measuring unit Known way Proposed method by examples 1 2 3 4 5 Hair coatings destruction scores 2 1 3 3 3 3 Collagenic protein destruction g / kg of skin 1.30 0.21 0.39 0.48 0.65 1.32

The use of less than 2% NaOH and more than 2% Na ₂ HPO _{4 results} in a worsening of hair coat disintegration, while the use of more than 3% NaOH and less than 1.5% Na ₂ HPO ₄ increases the collagen protein degradation.

Thus, the variants described in Examples 2, 3 and 4 are suitable for balding.

The present invention has the following advantages over the prior art:

- improves the quality of the finished bat by improving hair coat disruption and reducing collagen protein disruption.

- Reduces chemical utilization as Na ₂ HPO ₄ is more effective in reducing collagen degradation, while using a small amount of this substance in combination with a small amount of Na ₂ S improves the hair disintegration process, thus eliminating the need for such large amounts of NaOH for high quality hair removal. NaOH consumption is reduced by 5 to 2-3% of the raw weight of the skins. Na ₂ SO _{4 is} known to consume 15% of the raw material by weight, while Na ₂ HPO ₄ and Na ₂ S together account for 3.55 to 4.6% of the weight of the raw material.

Claims (2)

DEFINITION OF INVENTION 1. bare, the method is carried out in two steps A and B, the latter being in the step A solution of sodium hydroxide and salts thereof, characterized in that as a salt in step A using Na ₂ S and Na ₂ HPO _4, and in step b - ₂ Na HPO ₄ . 2. The method of producing baldness according to claim 1, characterized in that in step A 2.0-3.0% NaOH, 0.55-0.6% Na ₂ S and 1.5-2, 0% by weight of the raw material Na ₂ HPO ₄ , and in Stage B 1.5-2,0% by weight of the raw material Na ₂ HPO ₄ .