EP0763139B1 - Stuffing agents for leathers and fur-skins - Google Patents

Description

Field of the Invention

The invention relates to greasing agents for leather and furs containing selected anionic Surfactants and their use in the preparation of the compositions.

State of the art

In addition to the tannins, greasing agents are the most important tools to improve the character of leather shape. The effect of the greasing agents comes from a fiber-insulating lubrication and a Hydrophobization.

By covering the leather fibers with a grease film, the mutual friction is reduced and consequently improves the suppleness and stretchability of the fabric. That has positive effects the tensile strength of the leather, because many fibers are aligned in a stretchy material under tensile stress in the pulling direction and then subject the tearing to greater resistance contrary to the same fibers within a brittle material. Through the hydrophobization tanning effects are also achieved, since they are displaced with water from the Skin is connected.

Die verseifbaren Fette und Öle sowie die natürlichen Wachse und Harze gehören zu den Estern. Unter Ölen und Fetten werden dabei vom Lederfachmann Ester aus Glycerin und Fettsäuren bezeichnet, die bei Raumtemperatur fest bzw. flüssig sind. Zur Lederfettung werden dabei aus der Gruppe der tierischen Fette insbesondere Trane, Fischöl, Rindertalg und Rinderklauenöl, aus der Gruppe der pflanzlichen Fette Rizinusöl, Rüböl und Leinöl herangezogen. In Wachsen und Harzen sind die Fettsäuren statt mit Glycerin mit höhermolekularen Alkoholen verestert. Beispiele für Wachse sind Bienenwachs, chinesisches Wachs, Caranubawachs, Montanwachs und Wollfett; zu den wichtigsten Harzen zählen Kolophonium, Juchtenöl und Schellack.

Durch chemische Umwandlung pflanzlicher und tierischer Fette erhält man Produkte, die wasserlöslich sind und die darüber hinaus in unterschiedlichem Maße emulgierend auf wasserunlösliche Fettstoffe wirken. Bekannt sind etwa die sulfierten wasserlöslichen Öle verschiedenster Art, die durch Oxidation veränderten Trane, die als Dégras oder Moellon bezeichnet werden, ferner die Seifen, die bei der hydrolytischen Spaltung natürlicher Fette entstehen, gehärtete Fette sowie schließlich freie Fettsäuren wie Stearinsäure als Einbrennfette. Die meisten tierischen und pflanzlichen Fette weisen eine gewisse Affinität zur Ledersubstanz auf, die durch die Einführung oder Freilegung hydrophiler Gruppen noch beträchtlich gesteigert wird.

Wichtig für die Lederherstellung sind weiter die mineralischen Fettungsmittel. Diese Kohlenwasserstoffe sind den natürlichen Fetten und Ölen in manchen Eigenschaften ähnlich, lassen sich jedoch nicht verseifen. Es handelt sich um Fraktionen der Erdöldestillation, die in flüssiger Form Mineralöl, in pastöser Form Vaseline und in fester Form Paraffin genannt werden.

Vegetable and animal oils, fats and waxes are generally used as leather greasing agents, furthermore the hydrolysis, sulfation, oxidation and hardening products obtained from these substances by chemical conversion and finally mineral greasing agents; in detail:

The saponifiable fats and oils as well as the natural waxes and resins are among the esters. Oils and fats refer to esters of glycerin and fatty acids that are solid or liquid at room temperature. For leather greasing, from the group of animal fats in particular trane, fish oil, beef tallow and beef claw oil, from the group of vegetable fats castor oil, rape oil and linseed oil are used. In waxes and resins, the fatty acids are esterified with higher molecular weight alcohols instead of glycerin. Examples of waxes are beeswax, Chinese wax, caranuba wax, montan wax and wool fat; The most important resins include rosin, yeast oil and shellac.

The chemical conversion of vegetable and animal fats gives products that are water-soluble and, in addition, have different emulsifying effects on water-insoluble fats. For example, the sulfated water-soluble oils of various types are known, the tears modified by oxidation, which are referred to as dégras or moellon, the soaps which are formed during the hydrolytic splitting of natural fats, hardened fats and finally free fatty acids such as stearic acid as stoving fats. Most animal and vegetable fats have a certain affinity for the leather substance, which is considerably increased by the introduction or exposure of hydrophilic groups.

Mineral greasing agents are also important for leather production. These hydrocarbons are similar to natural fats and oils in some properties, but cannot be saponified. These are fractions from petroleum distillation, which are called mineral oil in liquid form, petroleum jelly in pasty form and paraffin in solid form.

In many cases, however, the surface of the tanned and greased leather forms over the course of the Time unwanted spots called "fatty spew". Fat rashes occur primarily on chrome-tanned leathers after shorter or longer storage than white ones, often a veil-like covering that only covers individual areas or the entire leather surface. The rash is due to the release of solid fatty substances from the leather. He can through that natural fat present in the leather itself or caused by fatty substances that only occur in the course of greasing the leather has been incorporated.

Fat mixtures used to grease leather tend to develop a rash if they contain a lot of free fatty acids. Free fatty acids generally have a higher melting point than their glycerides. The hydrolytic splitting of fatty substances during the storage of the leather increases the risk of fat rashes. Soaps and licker greases are split in chrome leather, especially in insufficiently deacidified chrome leather, with the release of fatty acids. Sulphated oils and fats show a different tendency to form fat rashes, the tendency to rash generally decreases with a longer lifespan [cf. J.Int.Soc.Leath.Trad.Chem. 47 , 379 (1952)]. Grease rashes are more likely to occur the more the leather contains fat substances that tend to form rashes. The amount, composition and location of the fat mixture of natural fat and lickerfat present in the leather are decisive for the extent and composition of the rash. Loosely structured leather is less prone to rash than leather with a dense fiber structure. Grease rashes are observed more often at low temperatures than at warmer outside temperatures. The crystalline fat rashes develop in the hair holes and gland canals, whereby small crystals are initially formed in the depth, which gradually fill the entire hair hole as larger fat crystals, swell out over the leather surface and matted into a dense crystal film. All fats that contain stearin or palmitin derivatives can cause crystalline fat rashes, with increasing concentration the risk of rashes increases [Ledertechn.Rundsch. 1 (1949)] . In particular, the so-called neutral fats, ie substances suitable for leather greasing that do not contain any ionic groups in the molecule, eg fats, waxes and hydrocarbons, tend to form fat rashes. Those neutral fats which represent stearin and / or palmitin derivatives, such as corresponding triglycerides or the free fatty acids, are particularly critical.

Because in the course of leather processing, but after tanning, it is an almost obligatory operation anyway it is necessary to apply grease in order to achieve the desired product properties in practice it has become common to work with special synthetic fatliquors, their tendency is low for the formation of fat rash.

One class of fatliquor commonly used in this regard is halogenated compounds such as chlorinated hydrocarbons. However, the increasing ecological and toxicological requirements for agents that get into the environment or with which the consumer comes into contact make this class of substances increasingly unattractive. Anionic surfactants are usually used for leather greasing. For example, from the European patent EP 0247509 B1 (Stockhausen) adducts of sulfuric acid or oleum with unsaturated, alkoxylated and optionally epoxidized fats and oils are known. In addition to reactions with oleum, sulfuric acid or gaseous sulfur trioxide, the sulfilization, ie the addition of hydrogen sulfite to unsaturated compounds, is also particularly suitable for the hydrophilization of fatty substances. In this context, for example, A. Kuenzel reports on the sulfitation of Dorschtran [Le der 8 , 5 (1957)] and M. Mikula on the sulfitation of unsaturated fatty acid butyl esters [Leder, Schuh, Lederwaren 21 , 282 (1986)] . From the German patent application DE-A1 4223704 (Henkel) also nonionic lubricants containing oleic acid esters and dialkyl ethers are known. Furthermore, reference is made to the European patent application EP 0247490 A1 , which describes sulfited fatty substances. EP 0353704 A1 finally relates to sulfonation products of oxyalkylated fatty acid lower alkyl esters.

However, the use of anionic fatliquoring agents is not without problems. An essential one The disadvantage is that a large number of these agents are used to form fat rashes tend. Furthermore, their biodegradability is not always satisfactory. Sulphated oils are viscous in the range of high active substance contents and can therefore often only be difficult dosing; after all, their color quality is often unsatisfactory.

The complex object of the invention was therefore to find new greasing agents for leather and Develop furs based on anionic surfactants, which are characterized by improved ecological and application technology Properties such as more comfortable grip and less tendency to become greasy award. The feedstocks should also be compared to the known sulfated or sulfited fatty substances have a better color quality and advantages in handling, especially in terms of exhibit the production of liquid, low-viscosity products.

Description of the invention

The invention relates to agents for greasing leather and furs with a content of 1 to 30% by weight of sulfonation products of unsaturated fatty acid C ₁ -C ₈ alkyl esters in the form of their alkali, alkaline earth, ammonium, alkylammonium, alkanolammonium or glucammonium salts.

Surprisingly, it was found that the sulfonation products of the invention are more unsaturated Fatty acid lower alkyl esters are not only completely biodegradable, but in comparison with others known anionic fatliquoring agents have a significantly lower tendency to form fat rashes exhibit. In addition, they also give leathers an improved lard or Suppleness, a pleasant grip and increased hydrophobicity. The sulfonation products are also highly concentrated and low viscosity and can therefore be easily dissolved in liquid, aqueous Incorporate formulations. In contrast, for example, to sulfated ester oils, they draw Finally, it also has an improved color quality.

Sulfation products

Sulfation products of unsaturated fatty acid lower alkyl esters are known substances that can be obtained by the relevant methods of preparative organic chemistry. A process for their preparation consists, for example, in reacting unsaturated fatty acid lower alkyl esters such as technical oleic acid esters with gaseous sulfur trioxide and then neutralizing the crude sulfonation product with an aqueous base and at the same time hydrolyzing cyclic intermediates such as sultones [DE 3803912 A1 (Henkel)]. Sulfonation is an electrophilic addition of the SO ₃ molecule to the double bond. Mixtures of isomeric hydroxy and alkene sulfonates are formed in the course of the neutralization or hydrolysis. An overview of this is provided by A. Behler et al. published in CR CESIO, Welttensidkongress Paris, Vol.11, p.14 (1988) . In a preferred embodiment of the invention, however, the sulfonation products are prepared by adding oleum to the unsaturated esters mentioned. Mixtures of sulfates and sulfonates are obtained. Sulfation products of unsaturated fatty acid alkyl esters of the formula (I) are preferably used, R ¹ CO-OR ² in which R ¹ CO represents an unsaturated acyl radical with 16 to 24 carbon atoms and 1, 2, 3, 4 and / or 5 double bonds and R ^{2 represents} a linear or branched alkyl radical with 1 to 8 carbon atoms. Typical examples are sulfonation products of esters of methanol, ethanol, butanol, octanol and in particular 2-ethylhexanol with palmoleic acid, oleic acid, elaidic acid, petroselinic 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 fatty acids, the sulfonation products can also contain technical fatty acid cuts with a predominantly unsaturated fraction as components such as rapeseed oil, sunflower and / or olive oil fatty acid as components. Sulfation products of oleic acid 2-ethylhexyl ester, in particular based on olive oil fatty acid in the form of the sodium salt, are preferably used.

Sulfation

The sulfonation of the unsaturated fatty acid lower alkyl esters can be carried out in the manner known for saturated fatty acid lower alkyl esters [J. Falbe (ed.), "Surfactants in consumer products", Springer Verlag, Berlin-Heidelberg, 1987, p. 61] , reactors according to Fall film principle work, are preferred. Sulfuric acid, oleum, chlorosulfonic acid and gaseous sulfur trioxide can be used as sulfating agents. The latter is usually diluted with an inert gas, preferably air or nitrogen, and used in the form of a gas mixture which contains the sulfonating agent in a concentration of 1 to 8, in particular 2 to 5,% by volume. The molar ratio of ester to sulfating agent in the case of chlorosulfonic acid or sulfur trioxide can be 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 use this in deficit, ie 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 from 15 to 90 ° C. With regard to the viscosity of the feedstocks on the one hand and the color quality of the resulting sulfonation products on the other hand, it has proven to be optimal to carry out 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. The bases for the neutralization are 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 -alkanolamines, for example mono-, Di- and triethanolamine as well as primary, secondary or tertiary C _1-4 -alkylamines and glucamines 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 be added in a manner known per se by adding Hydrogen peroxide or sodium hypochlorite solution are bleached. Here, based on the Solids content in the solution of the sulfonation products, 0.2 to 2 wt .-% hydrogen peroxide, calculated used as a 100% substance, or corresponding amounts of sodium hypochlorite. The pH of the Solutions can be prepared using suitable buffering agents, e.g. with sodium phosphate or citric acid be kept constant. To stabilize 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 - to a limited extent - also cationic surfactants. Typical examples of anionic surfactants are alkylbenzenesulfonates, alkanesulfonates, olefin sulfonates, alkyl ether sulfonates, glycerol ether, α-methyl ester sulfonates, sulfofatty acids, alkyl sulfates, fatty alcohol ether sulfates, Glycerol ether, Hydroxymischethersulfate, monoglyceride (ether) sulfates, fatty acid amide (ether) sulfates, mono- and dialkyl sulfosuccinates, mono- and Dialkyl sulfosuccinamates, sulfotriglycerides, amide soaps, ether carboxylic acids and their salts, fatty acid isethionates, fatty acid sarcosinates, fatty acid taurides, acyl lactylates, alkyl oligoglucoside sulfates and alkyl (ether) phosphates. If the anionic surfactants contain polyglycol ether chains, they can have a conventional, but preferably a narrow, homolog distribution. Typical examples of nonionic surfactants are fatty alcohol polyglycol ethers, alkylphenol polyglycol ethers, fatty acid polyglycol esters, fatty acid amide polyglycol ethers, fatty amine polyglycol ethers, alkoxylated triglycerides, alk (en) yl oligoglycosides, fatty acid-N-alkyl glucamides, polyol fatty acid sorbate sorbate sorbate esters, zukkester ester sorbate. If the nonionic surfactants contain polyglycol ether chains, they can have a conventional, but preferably a narrow, homolog distribution. Typical examples of amphoteric or zwitterionic surfactants are alkyl betaines, alkyl amido betaines, aminopropionates, aminoglycinates, imidazolinium betaines and sulfobetaines. Typical examples of cationic surfactants with which the anionic sulfonation products are compatible and do not form sparingly soluble salts are esterquats, in particular those which have ethylene oxide units in the molecule. The surfactants mentioned are exclusively known compounds. With regard to the structure and manufacture of these substances, reference is made to relevant reviews, for example, J.Falbe (ed.), "Surfactants in Consumer Products", Springer Verlag, Berlin, 1987, pp. 54-124 or J.Falbe (ed.), "Catalysts, Tenside und Mineralöladditive ", Thieme Verlag, Stuttgart, 1978, pp . 123-217 .

Fatliquor

In addition to the sulfonation products and other surfactants, the fatliquoring agents can be other common ones Auxiliaries and additives included. Usually the proportion of sulfonation products is Agents according to the invention 15 to 90 and preferably 20 to 80 wt .-% based on the agent. In As a rule, the agents are dosed so that 20 to 1 kg of leather or fur (calculated as fold weight) 1000, preferably 30 to 80 g of the agent are eliminated.

Industrial applicability

Sulfation products of unsaturated fatty acid lower alkyl esters confer as a component of fatliquoring agents Leather and fur have an improved lardiness and suppleness, a pleasant grip and increased water repellency. A particular advantage is that the sulfonation products are also highly concentrated and have low viscosity and are accordingly easy to use in liquid formulations have it incorporated. They also show in comparison with other known anionic fatliquoring agents a significantly lower tendency to form fat rashes. When using the invention Colorings are brilliant with good levelness. Another object of the invention relates therefore the use of the sulfonation products mentioned as anionic surfactants for greasing Leather and furs.

Examples

Manufacturing example H1. In a 1-liter sulfonation reactor with jacket cooling, 250 g (0.7 mol) of technical oleic acid 2-ethylhexyl ester (based on olive oil fatty acid with an oleic acid content of approx. 70% by weight) were initially charged and at a temperature of 31 to 33 ° C 44 g of oleum (20% by weight of SO ₃ ) were added in portions. The mixture was subjected to a subsequent reaction over a period of 90 min at 30 ° C. and then neutralized at about 55 ° C. with the addition of a mixture of 43 g ammonia in 89 g water. The resulting mixture was left to rest overnight, whereupon phase separation occurred. The aqueous phase containing the ammonium sulfate formed was then separated off and discarded. The organic value phase was adjusted to a pH of 7.5. The resulting oleic acid 2-ethylhexyl ester sulfonate / sulfate had the following composition: anionic surfactants: 42.3% by weight, unsulfated components: 42.0% by weight, sodium sulfate: 3.8% by weight, water: 11.9 % By weight. The anionic surfactant content (WAS) and the unsulfonated content (US) were determined according to the DGF standard methods, Stuttgart 1950-1984, H-III-10 and G-II-6b.

Manufacturing example H2. 362 g (1 mol) of technical grade 2-ethylhexyl oleic acid (based on olive oil fatty acid) were placed in a 1-liter sulfonation reactor with jacket cooling and reacted at 25 ° C. with 88 g (1.1 mol) of gaseous sulfur trioxide. The sulfur trioxide was expelled from a corresponding amount of 65% by weight oleum by heating, diluted to a concentration of 3% by volume and introduced into the starting product within 15 minutes. After the sulfonation, the acidic reaction mixture was stirred in portions into an aqueous 10% by weight base while maintaining a pH in the range from 7 and was neutralized in the process. The resulting oleic acid 2-ethylhexyl ester sulfonate had the following composition: anionic surfactants: 26.3% by weight, unsulfated components: 3.5% by weight, sodium sulfate: 1.1% by weight, water: 69.1% by weight. -%.

Example 1 . Manufacture of sheep clothing leather. Wet blue material was first washed and then retanned. The details of the amounts used and the duration of the process steps are summarized in Table 1. A soft leather with a full, round handle and an even, flowery color was obtained.

Example 2. Manufacture of furniture leather. Wet blue material was washed, retanned, neutralized, stained and greased. The details of the amounts used and the duration of the process steps are summarized in Table 2. Cloth-soft, chubby, slightly slimy furniture leather was obtained.

Example 3. Preparation of beef suede. Crust leather was paperback and dyed. The details of the amounts used and the duration of the process steps are summarized in Table 3. A silky suede fiber with brilliant coloring and a beautiful writing effect was obtained.

Example 4. Manufacture of cowhide leather. Wet blue material was washed, neutralized, washed again and retanned. The details of the amounts used and the duration of the process steps are summarized in Table 4. A very soft leather with good fullness and uniform, brilliant coloring was obtained.

Comparative Examples V1 to V4. Examples 1 to 4 were repeated, but a sulfated ester oil from the trade was used instead of the oleic acid 2-ethylhexyl ester sulfonate salt. The resulting leathers had a significantly harder grip and less lardiness. In addition, an uneven coloring was observed.

Claims (4)

1. Compositions for oiling leathers and skins containing 1 to 30% by weight of sulfonation products of unsaturated fatty acid C_1-8 alkyl esters in the form of their alkali metal, alkaline earth metal, ammonium, alkyl ammonium, alkanolammonium or glucammonium salts.
2. Compositions as claimed in claim 1, characterized in that they contain sulfonation products of unsaturated fatty acid alkyl esters corresponding to formula (I): R¹CO-OR² in which R¹CO is an unsaturated acyl group containing 16 to 24 carbon atoms and 1, 2, 3, 4 and/or 5 double bonds and R² is a linear or branched alkyl group containing 1 to 8 carbon atoms.
3. Compositions as claimed in claim 1, characterized in that they contain sulfonation products of oleic acid-2-ethyl hexyl ester.
4. The use of the sulfonation products claimed in claims 1 to 3 as anionic surfactants for the production of oiling compositions for leather and skins.