EP0015439A1 - Method of greasing leather and furs - Google Patents

Abstract

Phospholipids which are obtained within the framework of protein synthesis from fermentatively produced constituents of micro-organisms may be used, following a conversion into a water-dilutable form, for example by emulsification or by a chemical modification, such as saponification or sulfonation, as greasing agents for the greasing of leather and fur skins. In this capacity they are superior to vegetable and animal phospholipids.

Description

For the bio-industrial production of protein substances, the ability of certain microorganisms to multiply very quickly in nutrient solutions containing organic substances and from the carbon of the organic substances as well as added inorganic basic substances such as nitrogen, phosphoric acid etc., their cell components such as proteins, fats and Build nucleic acids. Synthetic nutrient media can also be used for this purpose if appropriate, specialized microorganisms are available.

On the basis previously explained, e.g. 1 kg of methanol-utilizing bacteria from methanol as a C source and nutrient medium produce 100 kg of single-cell protein per day.

If the cell mass obtained with the help of fermentative protein synthesis is digested with a mixture of ammonia and methanol at 20-30 ° C, the proteid portion remains undissolved, while 8-10% of the cell mass in the form of lipid-like substances in the methanol / ammonia Dissolve mixture.

After the evaporation of the solvent mentioned, a brown, water-insoluble lipid extract remains, which consists of over 60% of phospholipids and also trigl ^y- contains ceridic fats and free C ₁₆ fatty acids. In contrast to plant and animal phospholipids, the phospholipids isolated in this way, fermentatively and biosynthetically produced, are insoluble in apolar solvents. _;

It has now been found that these phospholipids obtained as a by-product with the aid of technological single cell protein production are very good leather greasing agents.

The present invention now relates to a process for greasing leather and fur, which is characterized in that liquid settings of emulsified or chemically modified lipid components from fermentatively obtained components of microorganisms at temperatures below the boiling point, preferably between 30 ° and 65 ° C, and normal pressure can act on the possibly colored substrate in the exhaust process, after which the substrate treated in this way is acidified as usual.

Similar to vegetable and animal lecithin, as found in egg or soybean oil, biosynthetic phospholipids also have a chemical softening and filling effect on leather, although they are chemically different from native lecithin. The good lubricating effect of natural lecithins from vegetable or animal oils has already been described many times, which is used in the leather industry.

Surprisingly, these biosynthetic phospholipids, which are produced by fermentation, are bound to the leather fiber much more firmly than the natural icithins obtained from egg or vegetable oils, in which the phosphate group bound to the glycerol residue as an ester is known to additionally contain strongly cationic organic bases, such as choline (2- Hydroxyethyl-trimethylammonimnhydroxid [(CH ₃ ) ₃ N-CH ₂ -CH ₂ -OH] ⁺ OH ^- ), is esterified.

The biosynthetically obtained lipids normally have to be separated from the protein-containing main products, since they have a smell and taste similar to mash and would therefore impair the protein obtained. Because of their impure form, they are therefore out of the question for nutritional purposes or feed. However, this mash-like smell does not bother the greasing of leather, as it is neutralized by the leather fiber and the vegetable and mineral tanning agents.

In order to be used as a fatliquor, these phospholipid extracts isolated from fermentative protein extraction by separating protein and nucleic acids first have to be prepared into a water-dilutable form.

To improve the solubility of the water-insoluble phospholipids, the products can, on the one hand, be converted into a water-emulsifiable form by the addition of anionic, cationic or nonionic emulsifiers by the known methods of emulsification technology.

On the other hand, it is also possible to convert phospholipids into a true water-soluble form by saponification with the addition of alkalis or low organic bases, for example according to the formula, using the given structural conditions, in particular the presence of the polyfunctional phosphoric acid esterified on the glycerol

In addition, the fat residues within the glycerol derivative symbolized above can be chemically modified with sulfuric acid, oleum, amidosulfonic acid or other known sulfonating agents without the triglyceride bond being broken down. The sulfo groups introduced in this way make the phospholipid water-soluble in alkaline, neutral and also in an acidic medium.

By adding 0.5 to 10% of nonionic stabilizing agents, it is then possible to render the sulfonated phospholipids mineral-salt resistant, so that they can even be used directly in aqueous chromium (III) salt tanning baths.

When leather is greased, the phospholipids produced by synthetic fermentation are clearly superior to the conventional vegetable and animal lecithin phospholipids in terms of their firm and chemical-cleaning-resistant bond to the leather fiber.

As early as 1933, Prof. Stather from the German Leather Institute Freiberg / Saxony reported that the egg yolk phospholipid fatty substances had much less binding power on chrome-tanned leather fibers than the stronger bond of sulfonated fish oils. He described (Collegium 1933, page 139) that, in contrast to sulfonated fish oils, all the egg yolk fat absorbed by the chrome leather can be extracted again and that no binding occurs with the chrome-tanned leather fiber.

In contrast, the "biosynthetic-fermentative" phosphilipid is firmly bound to the leather fiber. Even with a longer extraction time, only a portion of approx. 30% of the total fat absorbed by the leather can be extracted from the leather again. As can also be seen from Table 1 (see exemplary embodiments), About 70% of the organic fats introduced are firmly bound, while only about 20% of the plant or egg lecithins bind (% bound fat).

The consequence of this is that a leather greased according to the invention remains soft and supple after chemical cleaning and does not have to be regreased, as is usual with other greasing agents, as is also the case from the clearly low difference values of softness before and after chemical cleaning can recognize.

As a result, such greased leathers are particularly well suited for the manufacture of washable and dry-cleanable glove and clothing leathers, especially since they shrink less after the cleaning process than comparable differently greased leathers and thus retain their cut as a finished form and also significantly less in chemical cleaning their tensile strength values are reduced than the lecithin-greased leathers.

The percent (%) designation used in the above description and in the examples below refers - unless stated otherwise - to "percent by weight".

example 1

1000 g of a chemical engineering 81/7. Jan. 1974, pages - 62-63 or DE-AS 26 33 666 with the help of bacteria (Pseudo Monas spec. Or with Methylomonas Clara) lipid-containing raw cell protein mass obtained from methanol (as a C source), consisting of 75% crude protein , about 9% phospholipids, 10% nucleic acids, 5% ash and 1% fibers are split by treatment in four liters of a mixture of 400 g of aqueous ammonia (25%) and 3.6 liters of methanol at room temperature over the course of 20 minutes and filters off the undissolved defatted proteins using a vacuum filter. After the solvent has been distilled off, 90 g of a greenish-brown lipid mass which consists of 75% phospholipids, 3% triglyceridic fats and 15% free fatty acids and 7% lipoid compounds are obtained from the methanol filtrate.

Both the esterified and the free fatty acids have 95% chain length of approx. C _{16 '}

Example 2

70 parts of the lipid fraction obtained according to Example 1 were mixed with 20 parts of a C ₁₈ oxyethanesulfonic acid and 10 parts of soda and emulsified with the aid of 2 1 70 ° C warm water. The milky emulsion was added over a period of 10 minutes through the hollow axis into a rotating oiling drum on a 2 mm thick, 4.5 g moist beef box of 2000 g folding weight. This corresponds to 4.5% pure fat per fold weight.

After 30 minutes of flexing time at 50 ° C., the liquor was acidified as usual to improve the bath extract with the help of 2% formic acid and was further drummed for 15 minutes. After this time, all of the fat from the aqueous liquor was applied to the leather.

For a comparative assessment of the leather, see Table 1.

Example 3

70 parts of the lipid fraction obtained according to Example 1 were mixed with 20 parts of aqueous sodium hydroxide solution (35%) and further diluted with 2 l of warm water. The result was a clear solution with weak opalescence.

Analogously to Example 2, 2000 g of folded beef box from the same batch were greased with this solution. For the complete bath extract, however, the amount of formic acid added was increased from 2% here to 3.2%.

For a comparative assessment of the leather, see Table 1.

Example 4

70 parts of the lipid fraction obtained according to Example 1 were prepared with 20 parts of triethanolamine and 21 warm water to give an opal, cloudy solution, and this was greased in a manner analogous to Example 2 to 2000 g of cattle box.

For a comparative evaluation of the leather, see Table 1.

Example 5

A mixture of 15 g of concentrated sulfuric acid and 15 g of a mixture of 7 g of spindle mineral oil and a C ₁₆ sulfonic acid were added to 60 parts of the lipid fraction obtained according to Example 1 in the stirred flask over the course of 15 minutes, the temperature rising sharply. External cooling prevents the temperature from exceeding 60 ° C. in order to keep the cleavage of the triglyceride bond by the sulfuric acid as low as possible.

After a reaction time of 3 hours, the excess sulfuric acid was washed out of the sulfonate paste by treating twice with 100 ml of saturated sodium chloride solution and then the paste was neutralized by adding 20 ml of aqueous ammonia (25%). In this way, a brown paste was obtained which clearly dissolves in water even in the weakly acidic region below pH 7.

In the presence of 2 l of warm water, 2 kg of beef cattle were greased in the same way as in Example 2 in the drum with the solution obtained above.

Comparative evaluation of leather table 1.

Example 6

• 70 g eines handelsäblichen Soja-Lecithins (Ölmühle Mannheim) wurdenmit 20 Teilen einer C₁₈-Oxyäthansulfonsäure und 10 Teilen Soda analog Beispiel 2 vermischt. Mit Hilfe von 2 1 Wasser in wäßrige Dispersion gebracht und diese wurde wie dort auf Rindbox ausgefettet,
• Vergleichende Beurteilung der Leder in Tabelle 1.

Comparative greasing:

• 70 g of a commercial soy lecithin (Ölmühle Mannheim) were mixed with 20 parts of a C ₁₈ oxyethanesulfonic acid and 10 parts of soda as in Example 2. With the help of 2 l of water brought into aqueous dispersion and this was greased on cattle box as there,
• Comparative assessment of the leather in Table 1.

Example 7

• 70 g reines Ei-Lecithin (ERG.B.6 -Merck, Darmstadt) wurden mit 20 Teilen einer C₁₈-Oxyäthansulfonsäure und 10 Teilen Soda analog Beispiel 2 vermischt. Mit Hilfe von 2 1 70°C warmem Wasser in wäßrige Dispersion gebracht und die wurde wie dort auf 2 kg Chromrindbox ausgefettet.

Comparative greasing:

• 70 g of pure egg lecithin (ERG.B.6 -Merck, Darmstadt) were mixed with 20 parts of a C ₁₈ oxyethanesulfonic acid and 10 parts of soda as in Example 2. With the help of 2 1 70 ° C warm water brought in aqueous dispersion and was greased as there on 2 kg chrome cattle box.

Comparative assessment of the leather Table 1.

Example 8

• 130 g einer 70 %igen, wäßrigen Sulfonatpaste, hergestellt durch Verseifung eines auf einen Gehalt von 4,5 Mol-% sulfochlorierten Paraffinkohlenwasserstoffes mit C₁₈ bis C₂₂ Kettenlänge, wurden woe in Beispiel 2 beschrieben auf Rindbox ausgefettet und die Flotte wurde wie dort mit Hilfe von Ameisensäure ausgezogen.

Comparative greasing:

• 130 g of a 70% strength aqueous sulfonate paste, prepared by saponification of a paraffinic hydrocarbon having a chain length of C ₁₈ to C _{22 to a} length of 4.5 mol%, were greased on cattle box as described in Example 2 and the liquor was mixed with it as there Help stripped of formic acid.

For a comparative assessment of the leather, see Table 1.

All the leather greased according to Examples 2 to 8 were dried uniformly in a wind cabinet at 50 ° C., as usual with a wet chip, stubbed and then dried.

Claims (4)

1. A process for greasing leather and fur, characterized in that liquid settings of emulsified or chemically modified lipid components from fermentatively obtained components of microorganisms at temperatures below the boiling point and normal pressure on the possibly colored substrate in the exhaust process, after which the the treated substrate is acidified as usual. 2. The method according to claim 1, characterized in that one uses phospholipids which have been converted into a water-dilutable form with the aid of anionic, cationic or nonionic emulsifiers. 3. The method according to claim 1, characterized in that one uses phospholipids which have been converted into a water-dilutable form by saponification. 4. The method according to claim 1, characterized in that one uses phospholipids which have been converted into a water-dilutable form by sulfonation.