CS214044B1 - Method of production of tanned leather - Google Patents

Abstract

The invention relates to the leather industry. It solves the production of three-component leathers in a shortened way. The sallow prepared in a conventional way is delimed, acidified and treated in a bath consisting of 20 to 150% water and 0.1 to 5% condensate of a mixture of naphthalene mono, di and trisulfonic acids. The used tanning bath can be reused, preferably at the beginning of the next tanning cycle. Lubricants are added to improve the mechanical conditions during dynamic tanning. The invention can be used in all tanneries producing three-component leathers.

Description

SUMMARY OF THE INVENTION The present invention relates to a process for the production of leather in a shortened manner from descaled and acidified wort, which is treated in a bath composed of a condensate of a mixture of naphthalene mono-, di-, trisulfonic acids. It is followed by tanning with natural or synthetic tannins, or mixtures thereof. The waste tanning bath is reused preferably at the beginning of the next tanning cycle. This will significantly reduce the need for tannins and shorten the working cycle. The addition of lubricants before and during tanning prevents mechanical damage to the leather while on the move, replaces additional refining and speeds up the tanning process.

The prior art fast-speed methods utilize a higher deposition of naphthalene mono-, di- and trisulfonic acid condensates, at least%%, calculated on the tare weight. Further, a mixture of naphthalenesulfonic acids is used to acidify the wort. Their addition increases the tanning costs and in some cases results in a deterioration of the leather quality.

Higher deployment of naphthalene mono-, di- and trisulfonic acid condensate results in the formation of soft and skinned leather in addition to higher chemical costs. Excess condensates are discharged to wastewater or tanning baths where they can accumulate and cause recirculation problems.

Some of the drawbacks of the prior art are eliminated by the process of the present invention, which consists in using a condensate of a mixture of naphthalene mono, di and trisulfonic acids in an amount of from 0.1 to 5% calculated on the holin weight before tanning. Both naphthalenesulfonic acids, conventional piculum or weak organic acids can be used to acidify the wort. It is followed by tanning with natural or synthetic tannins, or mixtures thereof. The tanning bath after tanning can be reused best at the beginning of tanning of the next cycle and after exhaustion glued or drained into waste. In this way, tannins are better used, waste water pollution is reduced and process water is reduced. The wet process time is thus reduced to 24 to 48 hours depending on the weight of the leather. The use of tannins can be reduced by up to 50%.

Washing waters after tanning can also be used in the preparation of the tanning bath.

The whole process improves the addition of lubricants in an amount of 0.5 to 10% per weight by weight of the wort before or during the tanning process itself. This reduces the risk of mechanical damage to the leather under dynamic tanning conditions, increases the tanning speed of the leather, and improves removal of tannins from the bath.

The process according to the invention is concretized by the examples of use mentioned, but these are only a few of the many possible variants.

Example 1

The common ground prepared from cowhide leather is washed twice in 100% water in a tanner cask. Next, 50% water and 2.5% ammonium sulfate are added and allowed to move for 30 min. 0.1% hydrogen peroxide is then added and allowed to move for a further 30 min. The bath is drained, washed for 15 minutes and finally a bath of 100% water and 0.3% formic acid is prepared and left for 30 minutes. in motion. In addition, 3% of the mono-, di- and trisulfonic acid naphthalene condensate (Kortan R) and 5% of a synthetic tanning agent produced on the basis of beta-naphthol sulfonate condensed with phenol with sulfite leaches by formasldehyde (Kortan 11) are added. add 0.3% of acid214,044 formic acid and 0.1% sulfuric acid, moving for a further 30 min. After these operations, the ground is ready for further tanning, which takes place in a bath of 100% water and 15% mixture of natural and synthetic tannins within 24 hours. After tanning, wash twice with 100% water. The leather is further treated in a conventional manner.

Example 2.

The procedure is as in Example 1, at the beginning of the tanning, a tanning bath remaining from the previous cycle is used and after 2 hours it is drained and drained and the tanning is continued in a fresh tanning bath.

Example 3.

Following the procedure of Example 1, 2% of anionic lubricant was added simultaneously with the naphthalene sulfoacid condensate. An additional 4% of anionic lubricant is added during tanning.

Example 4.

Following the procedure of Example 1, washing water from the previous cycle together with a naphthalene sulfoacid condensate was used to prepare the formic acid bath.

Example 5.

The adobe is washed twice with 100% water and 3% of a mixture of inorganic salts and naphthalenesulphonic acid salts (Sokal) is added to the 100% water bath and 0.05% of Peline is added after 30 minutes of movement, rotating at 36 ° for a further 60 minutes. C. The bath is decanted and washed for 30 min at 25 ° C with warm water. Next, prepare a bath of 100% water and add 0.3% formic acid on the move and, after 30 minutes of movement, add 4% of mono-, di- and trisulfonic acid naphthalene condensate (Kortan R), 5% synthetic tannin beta-naphthol sulphonate base, condensed with phenol and sulphite leaches using formaldehyde (Kortan M), 0.3% formic acid and 0.1% sulfuric acid. After 120 minutes of movement, the ground is ready for tanning with a mixture of synthetic tannins, which takes place within 12 hours. All data are in percent by weight based on the weight of the weight.

Claims (3)

A process for the production of tanned leather by a shortened process from a wort which is optionally decalcified in a conventional manner and acidified, for example, with sulfuric acid or a weak organic acid or naphthalenesulphonic acids or a mixture of these acids, to a pH value 3.5 to 4.0, characterized in that the so prepared soils are treated in a bath composed of 20 to 150% water and 0.1 to 5% condensate of a mixture of naphthalene mono-, di- and trisulfonic acids containing at least 10% mixtures of di- and trisulphonic acids, calculated on the stick + · new weight, with the following tanning of natural or synthetic tanning substances or mixtures thereof. 2. A process for the manufacture of tanning leather from decalcified and acidified wort according to claim 1, characterized in that, after finishing the tanning, the bath is preferably used at the beginning of the tanning of the following cycle. 3. A process for the production of tanning leather from decalcified and acidified wort according to claim 1 and 2, characterized in that lubricants are added to the tanning baths during tanning.