CS235662B1 - Method of bark tanned leathers production by means of a shortened method - Google Patents

Abstract

Method of production TanSilted leather abbreviated, using a wax treatment with organic and inorganic acids and optionally mineral salts with subsequent addition of acid condensates naphthalene mono-, di-, and trisulfonic acid; mixtures with alkali modified sulfite leachates. The amount of acid is selected such that the pH of the resulting bath was between 2.0 and 4.5. The invention can be to use in the tanneries, producing tanning leather. Savings are achieved chemicals and reduces overall salinity wastewater ·

Description

SUMMARY OF THE INVENTION The present invention relates to a process for the production of tannic leather, abbreviated by the use of a clearing treatment with acids of organic and inorganic and possibly mineral salts, followed by the addition of naphthalene mono, di-trisulfonic acid condensate in a mixture with alkaline modified sulfite extracts. select such that the pH of the resulting bath is in the range of 2.0 to 4.5 ·

A number of processes using naphthalenesulphonic acid condensates to accelerate tanning are known to date · Most of these processes are used as raw materials in salted skins, which turn into desoins after leaching and leaching · These are decalcified, descaled and sealed after mechanical treatment bath with strong mineral acid and sodium chloride, which constitutes a major part of wastewater pollution · Mixtures of organic acids such as formic acid, acetic acid, naphthalenesulfonic acids, or together with strong mineral acid can be used in a separate bath in a separate bath. then discharges into wastewater. Further treatment of the ground is carried out in a new bath using naphthalene msn, di and trisulfonic acid condensates. In the new bath, tanning is carried out using a mixture of vegetable and synthetic tanning substances in a conventional manner. This bath is discharged again into the waste water after use. Further, methods are known in which one of the baths is plated and conditioned, but additional synthetic tanning agents need to be added to extend the operating time and increase the cost of the operation and increase the cost of chemicals.

Some of the disadvantages of the processes used hitherto are overcome by the process of the invention. It was found that by modification of sulfite

235 662 leaches carried out by heating the alkalinized desulphated sulphite leaches at a pH of between 7,5 and 10 for 10 hours

For up to 36 hours at a temperature of 80 to 135 ° C, a raw material with a high content of organic acid salts formed from sugars present in the extract, such as arabinose, galactose, glucose and mannose, is formed. The above-mentioned acids are predominantly aldonic acid and sugar acid · The sugar content decreases to zero, the content of reducing substances is almost unchanged · During the modification the pH drops to 6.5 · When the modified sulphite liquor is used in a mixture with naphthalene mono acid condensate salts The di, trisulfone, as a debris treatment agent may advantageously be combined with a debris acidification operation and conditioning and the above mixture. Compared to conventional processes, the subsequent tanning is thus accelerated and the resulting leather has a better feel and is more filled. At the same time, the amount of salts that leave unused to waste water and the amount of auxiliaries used during the conditioning operation are reduced.

The process according to the invention is illustrated by the following examples, which are only a few of the many possible variants. All data are calculated in% by weight per holin weight.

Example 1

100 parts by weight of decalcified sulphite liquor from coniferous wood, trees from which they are not removed by fermentation or by the production of feed yeast sugars, are heated to 95 ° C in an iron container. The pH is adjusted to 8-8.5 with 0.5 and 0.25 wt. parts of sodium hydroxide. The contents of the tank are mixed with pressurized air and left at 95-100 ° C for 24 hours. The content of monosaccharides, which in the decalcified original liquor is 17.5 to 30 g / l, decreases to 0.1 to 1.0 g / l. The pH value of the extracts drops to 7.0 to 7.5, when further standing it drops to ns 6 ₇ 9 ·

Preparation of naphthalene sulfonic acid condensate.

Into an enamelled reaction duplicator with a stirrer, add 1500 kg of naphthalene, melt and add 1550 kg of sulfuric acid 96 wt. The temperature is gradually raised to 175 ° C and maintained for 6 hours. Then cool and add at a temperature of 95 to 115 ° C gradually 600 kg of formaldehyde 40% wt.

- 3 235 682 and at the end of the formaldehyde feed 60 kg of urea. After completion of the reaction, allow to stir for 60 minutes and then adjust the dry matter of the product to 50% with water and neutralize to pH 6.5 - 7.5 with sodium hydroxide. Add 6000kg of treated sulphite liquors to the reaction mixture, mix and adjust the pH to 3.5 to 4.0 by addition of acetic or sulfuric acid. The resulting product is used either in liquid form or dried in a spray dryer ₀

Example 2

The original procedures used in conditioning the ground prepared in a conventional manner; The ground is put into a tannery barrel and processed according to the following procedure:

descaling and pickling 50% water

2.5% ammonium sulfate 0.1% hydrogen peroxide bath pour water

38 ° C min movement 30 min flow wash flow conditioning min movement% condensate mixture of naphthalene mono, di and tri • sulfonic acid% Kortan M (synthetic exchangeable tannic)

0,3% formic acid 0,1% sulfuric acid is carried out in a conventional manner by moving mixtures of vegetable and synthetic tannins for 24 hours

Another finish on the smoothing gear-ligaments.

min movement min movement tanning

Example 3

We will process the soil prepared according to the following technology:

decalcification and pickling 100% water 38 ° C% ammonium sulphate 30 min movement% Pelin 15 min bath drain

- 4,235 H2

Washing 2x 100% water 30 ° C 15 min. Pikl and forehead 80% water 25 ^e G 4% sodium chloride 0,7% sulfuric acid 0,5% acetic acid 40% 60 min 4% preparation according to · 1 1% lubricant M 120 min decant the bath, final pH 3.3-3.3 Tanning 150% water Deň: 29 ° C 20% mixture of vegetable and synthetic tříeliv movement 2x8 hours

the total tanning time is reduced for further use

washing 3 x 100% water Deň: 29 ° C pre-deletion 150% water 38®C fixation 4% Novorol333 1% molasses 1 magnesium sulphate 0,5% preparation according to example. 1 60 min movement 0.5% oxalic acid

After relubrication in a hot-air drum, we obtain leather which has improved yield, improved mechanical properties, in particular flexural elasticity and ductility suitable for adjusting the cuffs.

A comparison of the analytical values of the leather produced according to Examples 2, 3 and 4 is given in Table 1

Evaluation method leather made according to example

3 4

number of tanning 56.8 79.2 74.5 recovery number 175 210 230 tensile strength MPa 24.8 28.2 29.3 elongation% 39 45 40

Values given are the average of 10 determinations ·

Example δ. 4

235 662

We process perfectly blended, uncleaved clearing in croupons according to the following technology:

descaling and pickling 100% water 2% ammonium disulfide 0.5% Pelin stain Deň: 32 ° C 45 min 15 min . washing 2 x 100% water Deň: 29 ° C 20 min conditioning IDO% water Deň: 22 ° C t 4% sodium chloride 0.2% formic acid 0,5% kyp. sulfuric 30 min 2% preparation according to Ex. 1 0,5% grease M 60 min

decant the bath, final pH value of 3.5 - 4> We make the croupons in the jam in the pits with the values of the bath 40; 50; 70 ° E for 24 hours hitch in the pit tanning 100% water 30 ° C

0.5% preparation according to example 1 25% mixture of synthetic and natural tanning movement time 24 hours after tanning let leather hide for 24 hours

prahí 3 x 150% water 1direction, fixation 150% water 2% grease M 1% syntefix 0.5% Syntamine KX

0 20 min

38 ° C min

The leather produced according to the above regulation has a good yield and is suitable for the production of belt leather and saddlery leather with a reduction of labor intensity by 30% compared to the methods used so far.

Example 5

We will process the clearing prepared according to the usual operating method;?, According to the following technology:

Mixer type container

Descaling and pickling 100% water 38 ° C

1.5% ammonium sulfate 45 min

0.2% hydrogen peroxide 10 min

0.2% formic acid 20 min

235 662 washing picl, prewash x 100% water 80% water% sodium chloride 1% sulfuric acid 3,5%

30 ° C 15 min 25 ° C min

120 min shading of 100% bath obtained by recirculating wash water

30 ° C 60 min bath drain tanning

300% recirculated tanning bath with note 85 - 100 E

35®C tanning drum type 3520 hrs movement

150% water 35®C% blend of natural and synthetic tannins washing liquor% Lubricant M 150% water 150% water% Novorol 555

0.3% acid and v / v movement time 12 hours 35®G 3x30 mih

38®C

Said production method is suitable for leather and technical weighing leather with good yield, reduced water absorption and increased consumer-use properties (parameters).

The process according to the invention can be used in all tanneries of Czechoslovakia and abroad. This application simplifies the tanning process while improving the quality of the resulting leather

Claims (1)

OBJECT OF THE INVENTION 235 662 A method for producing a shortened manner třísločiněných leather boots of decalcification and treated by pickling in which the thus treated clearcut treated in a bath consisting of ₄ 20 to 200 wt. parts of water, 100 parts by weight of clay and 0.1 to 8 parts by weight of a mixture of naphthalene mono, di and trisulphonic acid condensates, characterized in that the modified sulphite extracts with a higher organic acid content of up to C? up to 400 wt. parts of the dry matter of modified sulphite extracts of 100kmoVL of naphthalene sulphonic acid condensate, the soil is penetrated, free of calcium cation residues and adapted for further tanning.