DE3114768A1 - "IRON II TANNING AGENT AND METHOD FOR TANNING ANIMAL SKIN AND SKIN" - Google Patents

Description

■ '-. ■': ■: ... 31U768

- 2 - Case 150-4434

Ferrous tanning agent and process for tanning animal hides and skins

The present application relates to solid tanning agents, which are powdery Contains iron (II) salts and masking agents, as well as their use for the production of leather.

So far, only Eiseri III salts have been used in practice for tanning purposes and for ferrous salts it has been claimed that they are not at all are suitable as tanning agents.

From French patent specification 881 676 it is known that iron (II) salts have a tanning effect. According to the description and example of this patent specification, the tanning is carried out with liquid iron (II) salt preparations. As agents that are used in tanning with iron (II) salts, According to the information in this patent specification, tartaric acid or citric acid come into consideration. According to the only example, the tanned is still used Subsequently, leather is oxidized.

Surprisingly, since its publication in FR-PS 381 676, iron-II tanning has never been mentioned again, and it has even been mentioned 1947 in a dissertation claims that iron (II) salts have no tanning effect. So it has been in the past, according to the publication FR-PS 881 676 can only claim the so-called "Ferrigan" tanning process with ferric salts as the only iron tanning.

The present invention now relates to a process for tanning of animal hides and skins with iron salts, which is characterized is that the tanning is carried out with powdered tanning agents made of divalent iron salts and aliphatic oxycarboxylic acids. The present invention also relates to those tanning agents in powder form which contain the aforementioned constituents, and finally the leather obtained with these tanning agents. Next is opposite

- 3 - Case 150-4434

the present invention was the combined chromium-iron (II) tanning with the above-mentioned means as well as such means themselves and the leathers produced in this way.

The iron (II) salt for the process according to the invention is FeSO, in Its (7 HO) form, which contains water of crystallization, is particularly preferred.

The organic oxy-acids resp. their salts are those with 2-8 carbon atoms, 1-3 carboxy groups and 1-6 hydroxyl groups. Tartaric acid is particularly suitable, as well as lemon, Malic, glycolic and lactic acid as well as gluconic acid and gluconic acid-3-lactone. Alkali or alkaline earth salts are suitable as salts, preferably the former, especially the Na salts, especially Na gluconate.

The amounts of iron (II) salts for the tanning to be carried out depend on various factors, such as the origin and nature of the pelts to be tanned, the type of leather desired and, above all, the type of leather the type of iron compound used and the associated according to the invention Masking agent.

In relation to the weight of the pimples, the Ferrous salt sequestrant mix usually between 7 and 40%, preferably about 13-25% used in the solid tanning according to the invention. In the powder tanning agents, however, the amount depends Tanning agent like the ratio of ferrous compounds to masking agent from the respective fur. The ratio is usually 3: 1 to 5: 1, especially 4: 1.

For a preferred system made of iron (II) sulfate (with 7 HO as water of crystallization) and tartaric acid, approximately the following amounts are used optimally, depending on the pelt:

Mixture according to the invention thereof FeSO, χ 7 H ^ O

Sheep and lambskin approx. 15.2% 12Z

Goat and kidskins 15.2% 12Z

Pigskins 20.3% 16Z

Calf and cattle skins 20.3Z 16Z

- 4 - Case 150-4434

The tanning process is preferably carried out in a known manner as for tanning with chrome tanning powder. This is how nakedness becomes first in the picked state with the powder mixture of FeSO, χ 7 HjO and Tartaric acid added (however, it is also necessary to dissolve it beforehand in water and Addition possible in this form). The small iron-II compound penetrates the skin in about 1-4 hours, depending on the concentration, temperature, number of revolutions of the drum and thickness of the material by adding soda, the pH value is increased to around 4.2-4.8. The number of sulfato groups in the complex is reduced and OH groups are introduced into the complex. This promotes the formation of multinuclear complexes, enlarges the individual particles and improves the tanning effect elevated.

After the tanning is finished, it is usually carried out for several days Storage (2-3 days) the tanning is finished. Then, if mixed, to be colored. As mentioned above, Fe (II) tanning can also be combined with chrome tanning.

The following examples serve to illustrate the invention. Parts are Parts by weight or volume, percentages are given in percentages by weight. th. All percentages relate to the weight of the pimples.

example 1

Become three defatted sheep picks weighing 2300g 100% saline solution 5% (30 ° C) in a glass vessel with a diameter of 60 cm and 10 revolutions per minute, 1% of one is put into the same bath amphoteric sulfo-containing fatty acid derivatives (commercial product, e.g. known as Tergolix A); after 10 minutes of running an addition is made of 0.8% formic acid 85% and 0.1% sulfuric acid cone. Leave for 30 min. keep walking. The final pH is 1.7.

Then 15% of an intimate mixture of 790 parts of FeSO ^ in powder form χ 7 H-O (dehydrated) and 210 parts of tartaric acid were added. After 2 hours

- 5 - Csae 150-4434

the final pH value is 1.8. 5.5% soda calc. (1:20 with Diluted water) slowly added dropwise within 2 hours, the final pH value is 4.9. After 1 hour of running, it is left in the bathroom overnight and in the morning it is left to run for 1 hour. The pH is 3.8. After adding a further 0.5% soda calc. (1:20 with water diluted) within 10 minutes by slowly adding dropwise, the mixture is allowed to run for another hour. The final pH is now 4.2.

The skins are stored for 3 days and have a light yellow-green color when they are wet. The hot water sample at 90 ^° C. (1 min.) Shows no shrinkage. The leathers are then withered (dehydrated) and shaved (equalized to the same thickness).

The following percentages now relate to the shaved weight. The tanned skins are washed first with 500% water 30 ⁰ C for 10 min for the neutralization, dyeing and fatliquoring. It is then allowed to run for 60 minutes with 300% water at 30 ^° C. and 1% sodium formate. (Final pH in the bath 4.9). The cut of the leather with bromocresol green is blue-green. For the coloring of a commercially available, anionic fatty acid derivative is added to 362 with 300% water (40 ⁰ C), and with 2% (eg, known as Sandolix WWL) and 3% of the dye CI Acid Brown and can be 45 min. Leach. 4% formic acid 85% are added and the mixture is allowed to run for a further 15 minutes.

Bierauf is washed with 500% water 30 ⁰ C, 15 min.. Fatliquoring is 300% Water 50 ⁰ C and with 4% of a commercial sulfated fish oil (for example, known as Sandolix 0) and an emulsion of a commercially available anionic synthetic fatty derivative (eg Sandolix SE) is performed. The running time is 60 minutes. Then 85% is acidified with 1% formic acid. It is then washed with 500% water at 30 ^° C. for 5 minutes. After it has been deposited on the trestle, the leather is wilted, (dehydrated) stretched out (smoothed on the grain side) and dried.

- 6 - Case 150-4434

After drying, the leathers are placed in moist sawdust and staked (softened) and stretched.

It is leather with good fullness, with level coloring, very good softness and good coloring.

Example 2

A pecked half beef pelt weighing 3200 g is treated in a glass barrel with a diameter of 60 cm and 8 revolutions per minute with 100% saline solution 5% at 20 ^° C. for 10 minutes, then 0.2% sulfuric acid is added and for 40 minutes run (final pH 1.6).

Then 20% of a powdery mixture of 790 parts FeSO.xyiLjO (dehydrated) and 210 parts of tartaric acid were added and the mixture was allowed to run for 4 hours (final pH 1.7).

After 5% soda (diluted 1:20 with water) in 5 portions at intervals of 30 minutes by slow dropwise addition, the mixture is left to run for 1 hour (final pH 4.2). It is left in the bath overnight and allowed to run for another 30 minutes the next morning (final pH 3.9).

1.5% soda (diluted 1:20 with water) are slowly added dropwise within 1 hour and then allowed to run for a further 1 hour (final pH 4.8).

After 3 days of storage, the leather has a light yellow-green inherent color in the moist state and the hot water sample at 90 ^° C. shows no shrinkage. The leather is withered and shaved after the specified time.

For the neutralization, dyeing and fatliquoring, the leather is washed first with 500% Waaser 30 ⁰ C for 10 min.. It is then treated with 300% water at 30 ^° C. and 0.8% sodium formate for 30 minutes (final pH bath 4.8). The cut of the leather with bromocresol green is blue-green on the outside and yellow on the inside. It is now washed with 500% water 30 ⁰ C for 10 minutes, whereupon the

31H768

- 7 - Case 150-4434

Coloring is done. For this purpose, with 300% water at 40 ^° C., 2% of a commercially available anionic fatty acid derivative (see Example 1) and 1% of the dye CI Acid Brown 362 are allowed to run for 30 minutes.

With 5% formic acid 85% (diluted 1:10 with water) it is slightly acidified within 15 minutes. The fatliquoring is done with 300% water at 40 ⁰ C and in Example 1 indicated aids (equal amounts) within 45 minutes.The acidification is with 0.5% formic acid for 10 min. Performed finally maintained for 5 min with 500% water. Washed.

After drying, the leather is placed in moist sawdust and staked (softened) and stretched.

A leather with good body and a somewhat firm grip is obtained. Example 3

All percentages relate to the pimple weight. 2 Schafpickelblössen, degreased, with a weight of 1500g strength sodium chloride solution at 30 ⁰ C in a glass vessel of 60 cm diameter and 10 revolutions / min, in 100% of a 5% added thereto is 10 min. Run. It is now in powder form, 20% of a mixture of 819 parts of FeSO 7H 0 dehydrated, 74 parts of tartaric acid and 107 parts of sodium gluconate are added and the mixture is allowed to continue for 2 hours, the final pH is now 2.0. Then 6% soda, diluted 1:20, is added in 5 portions at intervals of 30 minutes. Then it is allowed to run for a further 2 hours, the final pH is 4.5. The skins are placed on a buck. The hot water test,

1 hr. After tanning at 9O ⁰ C, 1 min., Shows snapped ijchrunipfuüg. Example 4

All information relates to the pelt weight.

2 halves of beef with a pelt weight of 7200g are like a normal one Chrome tanning decalcified, pickled and peeled. Then will

■ ' - 31U768

- 8 - Case 150-4434

the tanning started with 3% of a commercially available chrome tanning agent (with 26% chrome oxide and 33% basicity); after a running time of two hours, 8% of a mixture of 790 parts of FeSO, χ 7H ₂ O, is dehydrated, and 210 parts of tartaric acid are added. After running for a further 2 hours, 3% soda, diluted 1:20, is slowly added dropwise over the course of 2 hours. It is allowed to run for a further 2 hours, the final pH value is 4.6. The halves of the beef are placed on a trestle. The hot water sample, 1 hour after tanning at 90 ^° C. for 1 minute, shows no shrinkage.

Example 5

All percentages relate to the dry weight of the pelts (furs). 2 Australian lambskins of 620g are soaked, fleshed, washed and peeled as usual. Make the pimple become one Day, then the tanning takes place. The skins are in a bath of 2000% water 35 ° C, 50 g / l table salt and 0.5 g / l of an amphoteric, Fatty acid derivatives containing sulfo groups (commercial product, e.g. Tergolix A) are given. After running for 20 minutes, 16 g / l of a mixture of 790 Parts of FeSO, χ 7H-O, dehydrated, and 210 parts of tartaric acid 1: 4 in water Dissolved at 25 ° C., added.

After 2 hours running, 4 g / l of a cationic polyglycolated aliphatic Ester amides (commercial product e.g. Katalix GS) added in aqueous emulsion. After running for two hours, 5 g / l sodium bicarbonate is added dulled. This addition is made slowly in 5 portions, 30 minutes apart. The mixture is then allowed to run for a further hour.

The skins are then stored for 1 day. The hot water sample at 80 ^° C. for 1 minute shows no shrinkage.

Claims (5)

31 H768 SANDOZ-PATENT-GMBH Case 150-4434 L ö r r a c h Iron-II tanning agent and process for tanning animal hides and skins Patent claims 1. Process for tanning animal hides and skins with iron salts, characterized in that the tanning is carried out with powdered tanning agents made from divalent iron salts and aliphatic oxycarboxylic acids performs. 2. The method according to claim 1, characterized in that the Qxycarboxylic acid Tartaric acid, citric acid or gluconic acid, the latter especially in the form of the Na salt, can be used. 3. The method according to claims 1 and 2, characterized in that the tanning with the additional use of tanning chromium salts
is carried out. 4. Solid, powdery tannins containing the components of the in the claims 1 and 2 mentioned Art. 5. The leather obtainable with the tanning agents according to claim 4.