DE4418942A1 - Compsn. for dubbing leather and skins - Google Patents

Abstract

Proposed are new stuffing agents for leathers and fur-skins, containing sulfitation products of unsaturated fatty acid low-alkyl esters as anionic surfactants. The agents lend leathers an improved suppleness and increased hydrophobicity and are characterized by less inclination to form fatty spew as well as an advantageous ecotoxicological tolerability.

Description

Field of the Invention

The invention relates to lubricants for leather and furs a content of selected anionic surfactants and their Use to make the funds.

State of the art

In addition to the tannins, the most important are fatty acids Tools to shape the character of leather. The We The fatliquor comes from a fiber insulating Lubrication and by hydrophobization.

By covering the leather fibers with a grease film, the mutual friction is reduced and therefore the slack Tension and stretchability of the fabric improved. That has po sitive impact on the tear resistance of the leather, because In a stretchy material, many fibers are attached Tensile stress in the direction of tension and then expose it Tearing up a greater resistance than the same Fibers within a brittle material. Through the  Hydrophobing will also have tanning effects aims as it is with a displacement of water from the skin connected is.

Vegetable and animal oils, fats and waxes are used, as well as those from Hydro obtained from these substances by chemical conversion lysis, sulfation, oxidation and hardening products and finally mineral greasing agents; in detail:

• - The saponifiable fats and oils as well as the natural ones Waxes and resins are among the esters. Under oils and Fats are made by the leather specialist ester from glycerin and fatty acids that are solid at room temperature or are liquid. For leather greasing, the Group of animal fats, in particular tears, fish oil, Beef tallow and claw oil, from the group of vegetable fats castor oil, rape oil and linseed oil pulled. The fatty acids take place in waxes and resins esterified with glycerin with higher molecular weight alcohols. Examples of waxes are beeswax, Chinese Wax, caranuba wax, montan wax and wool fat; to the main resins include rosin, and yeast oil Shellac.
• - By chemical conversion of plant and animal Fats are products that are water-soluble and which are also emulsifying to varying degrees act on water-insoluble fatty substances. Are known for example, the sulfated water-soluble oils of various types Kind, the Trane changed by oxidation, which as  D´gras or Moellon are called, furthermore the Sei fen, which are more natural in hydrolytic splitting Fats are formed, hardened fats and finally free ones Fatty acids such as stearic acid as stoving fats. The mei Most animal and vegetable fats have a ge know affinity for the leather substance caused by the Introduction or exposure of hydrophilic groups still be is increased dramatically.
• - The mine is also important for leather production ralic fatliquor. These are hydrocarbons the natural fats and oils in some properties similar, but cannot be saponified. It deals fractions of petroleum distillation, which in liquid mineral oil, in pasty form petroleum jelly and in solid form can be called paraffin.

In many cases, however, the surface of the Tanned and greased leather undesirable over time Stains known as "fatty spew" become. Fat rashes occur primarily on chrome-tanned leathers after shorter or longer storage than white, often veil-like covering, which only single places or also covered the entire leather surface. The rash is on Leakage of solid fatty substances from the leather Ren. It can through the natural fat present in the leather or caused by fatty substances that only come in the course of The leather has been greased.

Fat mixtures used for greasing leather tend to tend then to form a rash if they have a lot of free  Contain fatty acids. Free fatty acids generally have a higher melting point than their glycerides. The hy drolytic splitting of fatty substances during storage of the Leather accordingly increases the risk of occurrence of Fat rashes.

Soaps and licker greases are made in chrome leather, especially in not enough deacidified chrome leather, releasing Split fatty acids. Sulphated oils and fats have one different tendencies to form fat rashes on, the tendency to deflect goes with a longer lifespan generally back [cf. J. Int. Soc. Leath. Trad. Chem. 47, 379 (1952)].

Greasy rashes occur the easier the leather contains fatty substances that tend to develop rashes. For the The scope and composition of the rash are quantity, Composition and location of the fat in the leather mix of natural fat and lickerfat decisive. Relaxed Textured leather is less prone to rash than Leather with a dense fiber structure. Fat rashes are at low temperatures observed more often than at warmer ones Outside temperatures.

The crystalline fat rashes develop in the hair holes and glandular canals, initially with small crystals in of the depths that are gradually formed as larger fat crystals fill the whole hair hole, over the leather upper swell out and form a dense crystal film felting. All fats that contain stearin or palmitin derivatives hold, can cause crystalline fat rashes with  Increasing concentration increases the risk of a rash ßert [leather techn. Circular 1 (1949)].

In particular, the so-called neutral fats, i.e. H. such substances suitable for leather greasing which are not ionic Contain groups in the molecule, e.g. B. fats, waxes and coals hydrogen, for the formation of fat rashes. Especially those neutral fats, the stearin and / or are critical Represent palmitine derivatives, such as corresponding Triglycerides or the free fatty acids.

Since in the course of leather processing, but after tanning, oh greasing as an almost obligatory work step is required to achieve the desired product properties achieve, it has become common in practice, with special len synthetic fatliquors work, their tendency is low for the formation of fat rash.

A class of. Commonly used in this regard Fatliquoring agents are halogenated compounds such as chlorinated carbon Hydrogen oils. The increasing ecological and toxicological requirements for agents that get into the environment, or with which the consumer comes into contact however, this class of substances is increasingly unattractive.

Anionic surfactants are usually used for leather greasing set. For example, from the European patent Publication EP-B 0247509 (Stockhausen) addition products from Sulfuric acid or oleum to unsaturated, alkoxylated as well optionally known epoxidized fats and oils. In addition to Um settlement with oleum, sulfuric acid or gaseous sulfur  trioxide is used for the hydrophilization of fatty substances especially sulfitation, d. H. the attachment of Hydrogen sulfite on unsaturated compounds. So is in this context, for example, by A. Küntzel the sulfitation of Dorschtran [Leder 8, 5 (1957)] and of M. Mikula on the sulfitation of unsaturated fatty acids tylestern [Leder, Schuh, Lederwaren 21, 282 (1986)] berich tet.

From German patent application DE-A1 42 23 704 (Henkel) also nonionic fatliquor containing oil acid esters and dialkyl ethers known.

However, the use of anionic fatliquoring agents is not free of problems. A major disadvantage is that a variety of these agents are in use for education of fat rashes. Furthermore, their biological Degradability is not always satisfactory. Sulphated oils are viscous in the area of high active substance contents and can therefore often be dosed only with difficulty; after all, their color quality is often unsatisfactory.

The complex object of the invention was therefore new greasing agents for leather and furs based on anionic Develop surfactants that are characterized by improved ecological and application properties such. B. more pleasant Characterize grip and less tendency to become greasy. The feedstocks should also be compared to the known sul greased or sulfited fatty substances a better color quality and advantages in handling, especially in the outward direction  view of the production of liquid, low-viscosity products exhibit.

Description of the invention

The invention relates to agents for greasing leather and furs containing 1 to 30% by weight of sulfia products of unsaturated fatty acid lower alkyl esters in Form of their alkali, alkaline earth, ammonium, alkylammonium, Alkanolammonium or glucammonium salts.

Surprisingly, it was found that the inventive Sulfation products of unsaturated fatty acid lower alkyl esters are not only completely biodegradable, but in Comparison with other known anionic fatliquoring agents a significantly lower tendency to form fat have blows. They also lend leather an improved lardiness or suppleness, a pleasant take grip as well as increased hydrophobicity. The sulfy ration products are also highly concentrated and low viscosity can therefore be easily converted into liquid, aqueous formulations incorporate. In contrast, for example, to sulfated Finally, they are also characterized by ester oils an improved color quality.  

Sulfation products

Sulfation products of unsaturated fatty acid lower alkyl esters represent well-known substances that according to the relevant Me preparative organic chemistry can.

For example, there is a method for producing them therein unsaturated fatty acid lower alkyl esters such. B. technical oleic acid esters with gaseous sulfur trioxide add and then the crude sulfonation with neutralize an aqueous base and at the same time cyc Intermediates such as sulfones to hydro lyse [DE-A1 38 03 912 (Henkel)]. In the sulfonation han it is an electrophilic addition of the SO₃ molecule to the double bond. In the course of neutralization or hy Mixtures of isomeric hydroxy and alkenesulfonates are used for hydrolysis educated. An overview of this is provided by A. Behler et al. in C.R. CESIO, World Surfactant Congress Paris, Vol. II, p. 14 (1988) appeared.

In a preferred embodiment of the invention, the However, sulfonation products by the addition of oleum to the called unsaturated esters. Here are Obtained mixtures of sulfates and sulfonates.

Sulfation products of unsaturated are preferred Fatty acid lower alkyl esters of the formula (I) used,

R1 CO-OR2 (I)

in the R1 for an unsaturated acyl radical with 16 to 24 Koh lenstoffatomen and 1, 2, 3, 4 and / or 5 double bonds and R² is a linear or branched alkyl radical having 1 to 8 Carbon atoms.

Typical examples are sulfonation products of esters of Methanol, ethanol, butanol, octanol and especially 2-ethylhexanol with palmoleic acid, oleic acid, elaidic acid, Pe troselinic acid, linoleic acid, linolenic acid, elaeostearic acid, Gadoleic acid, behenic acid and clupanodonic acid and their technical mixtures in the form of their sodium, potassium and / or Ammonium salts. In addition to the pure unsaturated fat Acids can also be used as components in the sulfonation products technical fatty acid cuts with predominantly unsaturated Share such as rapeseed oil, sunflower and / or oli contain veno fatty acid. Sulfation are preferred Products based on 2-ethylhexyl oleic acid, in particular based of olive oil fatty acid used in the form of the sodium salt.

Sulfation

The sulfonation of the unsaturated fatty acid lower alkyl esters can be known in the for saturated fatty acid lower alkyl esters ten wise man [J. Falbe (ed.), "Surfactants in consumer products", Springer Verlag, Berlin-Heidelberg, 1987, p. 61], wherein reactors that work on the falling film principle, be are preferred. Sulfuric acid, oleum, Chlorosulfonic acid and gaseous sulfur trioxide in Be dress. The latter is usually carried out with an inert gas, preferably diluted in air or nitrogen and in the form of a  Gas mixture which contains the sulfonating agent in a concentration contains from 1 to 8, in particular 2 to 5% by volume.

The molar ratio of ester to sulfating agent can in the case of chlorosulfonic acid or sulfur trioxide 1: 0.95 to 1: 1.3 and preferably 1: 1.0 to 1: 1.15. If sulfuric acid or oleum is used as the sulfonating agent, it is advantageous to do this in deficit, d. H. for example in a molar ratio of 1: 0.1 to 1: 0.95 and in particular 1: 0.25 to 1: 0.8.

The sulfonation is usually carried out at temperatures from 15 to 90 ° C carried out. With regard to the viscosity of the A Substitutes on the one hand and the color quality of the resulting Sulfation products on the other hand, it has been found to be optimal proved the reaction in a temperature range from 20 to 30 ° C.

Neutralization

The acidic sulfonation products obtained during the sulfonation are stirred into aqueous bases, neutralized and adjusted to a pH of 6.5 to 8.5. As bases for the neutralization come alkali metal hydroxides such as sodium, potassium and lithium hydroxide, alkaline earth metal oxides and hydroxides such as magnesium oxide, magnesium hydroxide, calcium oxide and calcium hydroxide, ammonia, mono-, di- and tri-C _2-4 -alkanol amines, for example mono -, Di- and triethanolamine and primary, secondary or tertiary C _1-4 alkylamines and gluca mine into consideration. The neutralization bases are preferably used in the form of 5 to 55% by weight aqueous solutions, 5 to 25% by weight aqueous sodium hydroxide solutions being preferred.

Bleaching and preservation

After neutralization, the sulfonation products can in themselves known manner by adding hydrogen peroxide or Na trium hypochlorite solution are bleached. Here, bezo gene to the solids content in the solution of the sulfation pro products, 0.2 to 2 wt .-% hydrogen peroxide, calculated as 100% Substance, or equivalent amounts of sodium hypochlorite used. The pH of the solutions can be changed using suitable buffering agents, e.g. B. with sodium phosphate or Ci tronic acid are kept constant. For stabilization ge against bacterial attack, preservation is also recommended, e.g. B. with formaldehyde solution, p-hydroxybenzoate, sorbic acid or other known preservatives.

Cotenside

The sulfonation products according to the invention can be used alone, but preferably in a mixture with other anionic, nonionic, amphoteric or zwitterionic surfactants and - limited - who uses cationic surfactants the.

Typical examples of anionic surfactants are alkylbenzene sulfonates, alkanesulfonates, olefin sulfonates, alkyl ether sulfo  nate, glycerol ether sulfonates, α-methyl ester sulfonates, sulfo fatty acids, alkyl sulfates, fatty alcohol ether sulfates, glycerin ether sulfates, hydroxy mixed ether sulfates, monoglyceride (ether) sulfates, Fatty acid amide (ether) sulfates, mono- and dialkyl sulfo succinates, mono- and dialkylsulfosuccinamates, sulfotriglyce ride, amide soaps, ether carboxylic acids and their salts, fat acid isethionates, fatty acid sarcosinates, fatty acid taurides, Acyl lactylates, alkyl oligoglucoside sulfates and alkyl (ether) phosphates. If the anionic surfactants polyglycol ether ket ten, they can be conventional, preferably however, have a narrow homolog distribution.

Typical examples of nonionic surfactants are fatty alcohols holpolyglycolether, alkylphenolpolyglycolether, fatty acid po lyglycol ester, fatty acid amide polyglycol ether, fatty amine poly glycol ethers, alkoxylated triglycerides, alk (en) yloligoglyko side, fatty acid-N-alkylglucamides, polyol fatty acid esters, zuc keresters, sorbitan esters and polysorbates. If not ionic surfactants containing polyglycol ether chains, they can a conventional, but preferably a restricted Ho have molog distribution.

Typical examples of amphoteric or zwitterionic surfactants are alkyl betaines, alkyl amido betaines, aminopropionates, amino glycinates, imidazolinium betaines and sulfobetaines.

Typical examples of cationic surfactants with which the anionic sulfonation products are compatible and none Poorly soluble salts are esterquats, in particular those that have ethylene oxide units in the molecule.  

The surfactants mentioned are exclusively known connections. In terms of structure and manufacture these substances are included in relevant reviews for example J. Falbe (ed.), "Surfactants in Consumer Pro ducts ", Springer Verlag, Berlin, 1987, pp. 54-124 or J. Falbe (ed.), "Catalysts, surfactants and mineral oil additives", Thieme Verlag, Stuttgart, 1978, pp. 123-217.

Fatliquor

In addition to the sulfonation products and other surfactants other common auxiliary and additive fe included. The proportion of sulfia is usually tion products on the agents 15 to 90 and preferably 20 to 80 wt .-% based on the agent. In the As a rule, the agents are dosed so that 1 kg of leather or Fur (calculated as fold weight) 20 to 1000, preferably 30 up to 80 g of the agent are eliminated.  

Industrial applicability

Sulfation products of unsaturated fatty acid lower alkyl esters lend leather and pel as a component of greasing agents improved lardiness and suppleness, one pleasant grip and increased water repellency. A special their advantage is that the sulfonation products are also highly concentrated and have a low viscosity can be easily incorporated into liquid formulations. Compared to other known anionic fatliquoring agents They also show a significantly lower tendency to Formation of fat rashes. When using the fiction medium, the dyeings are brilliant with good levelness out.

Another object of the invention therefore relates to the Ver use of the sulfonation products mentioned as anionic Surfactants for greasing leather and furs.

Examples Manufacturing example H1

Preparation of oleic acid 2-ethylhexyl ester sulfonate / sulfate sodium salt. In a 1 liter sulfonation reactor with jacket cooling were 250 g (0.7 mol) technical grade oleic acid 2-ethylhexyl ester (Based on olive oil fatty acid with an oleic acid content of approx. 70 Wt .-%) submitted and at a temperature of 31 to 33 ° C. in portions with 44 g of oleum (20 wt .-% SO₃). The Mixture became one over a period of 90 min at 30 ° C Subsequent reaction and then with the addition of a mixture neutralized by 43 g ammonia in 89 g water at approx. 55 ° C. The resulting mixture was left overnight whereupon phase separation occurred. Then the aqueous phase containing the ammonium sulfate formed separates and discards. The organic value phase was on egg set a pH of 7.5. The characteristics of the product are summarized in Table 1:

Table 1

Oleic acid 2-ethylhexyl ester sulfonate / sulfate

The anionic surfactant content (WAS) as well as the unsulfated components (US) were based on the DGF standard methods, Stuttgart 1950-1984, H-III-10 and G-II-6b determined.

Manufacturing example H2

Preparation of oleic acid 2-ethylhexyl ester sulfonate sodium salt. In a 1 liter sulfonation reactor with jacket cooling 362 g (1 mol) technical grade oleic acid 2-ethylhexyl ester (basis Olive oil fatty acid) and at 25 ° C with 88 g (1.1 mol) gaseous sulfur trioxide implemented. The sulfur trioxide was 65% by heating from an appropriate amount Oleum driven out to a concentration of 3% by volume diluted and within 15 min in the starting product initiated. After sulfation, the acidic reaction Mix in portions in an aqueous 10% by weight base Maintaining a pH in the range of 7 and stirred neutralized in the process. The characteristics of the product are in Table 2 summarized:

Table 2

Oleic acid 2-ethylhexyl ester sulfonate

Example 1

Manufacture of sheep clothing leather. Wet blue material was de first washed and then retanned. The Anga ben on quantities used and duration of the process steps are summarized in Table 3. Understand all percentages based on the fold weight.

Table 3

Manufacture of sheep clothing leather

It became a soft leather with a full, round handle and get a uniform, flowery color.

Example 2

Manufacture of furniture leather. Wet blue material was made tanned, retanned, neutralized, colored and greased. The Information on amounts used and duration of the process step te are summarized in Table 4. All percentages understand each other in relation to the fold weight.  

Table 4

Manufacture of furniture leather

There was cloth-soft, chubby, slightly slimy furniture leather receive.

Example 3

Production of beef suede. Crust leather was paperback and colored. The information on the quantities used and the duration of the ver Driving steps are summarized in Table 5. All pro percentages are based on the fold weight.

Table 5

Production of beef suede

It became a silky suede fiber with a brilliant color exercise and nice writing effect.

Example 4

Manufacture of cowhide leather. Wet blue material was chosen washed, neutralized, washed again and retanned. The Information on amounts used and duration of the process steps are summarized in Table 6. Understand all percentages based on the fold weight.  

Table 6

Manufacture of cowhide leather

It became a very soft leather with good fullness and the same moderate, brilliant coloring.

Comparative Examples V1 to V4

Examples 1 to 4 were repeated instead of the oil acid re-2-ethylhexyl ester sulfonate salt, however, a sulfated Ester oil used in the trade. The resulting leather like a harder grip and less lardiness on. In addition, an uneven coloring was observed.

Claims (4)

1. Means for greasing leather and furs with a content from 1 to 30% by weight of unsaturated sulfonation products Fatty acid lower alkyl esters in the form of their alkali, alkaline potash, ammonium, alkylammonium, alkanolammonium or Glucammonium salts. 2. Composition according to claim 1, characterized in that it Low sulfation products of unsaturated fatty acids contain alkyl esters of the formula (I), R¹CO-OR² (I) in R¹ for an unsaturated acyl radical with 16 to 24 Carbon atoms and 1, 2, 3, 4 and / or 5 double bin dungen and R² for a linear or branched Alkyl radical having 1 to 8 carbon atoms. 3. Means according to claim 1, characterized in that it Sulfation products of 2-ethylhexyl oleic acid ent hold. 4. Use of sulfonation products according to the claims 1 to 3 as anionic surfactants for the production of fet agents for leather and furs.