EP1585839B1 - Method for degreasing animal skins at ultralow interfacial surface tension - Google Patents

Description

The present invention relates to compositions used in the removal of fats from substrates selected from the group consisting of hides, skins, pelts and other intermediates in leather and fur manufacture, a process for removing fats from said substrates, use said compositions in the removal of fats from the substrates.

The removal of natural fat from animal skins is essential for the production of high quality leather and fur skins, especially for skins with medium and high natural fat content. The distribution of performance chemicals in the degreasing following stages of leather and fur production is significantly improved by the degreasing, so that e.g. a uniform tanning and dyeing is possible. If there is no removal of natural fat, then the end product is spotty in the case of leather and / or obtained by bacterial degradation of fats and crystallization of high molecular weight saturated fatty acids during storage fatty spikes that can affect the leather optically and physically negative. Fur skins show a unevenly colored velor side, in addition local hardening with risk of breakage of the fur leather can occur.

According to the prior art, essentially two methods are used for degreasing animal skins: solvent degreasing and emulsifier degreasing.

The solvent degreasing is a degreasing with organic solvents. It can either without addition of water (dry degreasing) or in the presence of water (Wet degreasing) done. Due to the use of organic solvents, solvent degreasing leads to considerable environmental pollution, which is already unsustainable in many countries today.

For these predominantly ecological reasons, emulsifier degreasing, which completely dispenses with the use of organic solvents, is predominantly carried out today. In particular, nonionic surfactants are suitable as emulsifiers in this process, since they have no binding power to the skin or leather fibers. Thus, they can optimally solubilize the natural fat of the animal skins without being hindered by interactions with the animal skin. Known nonionic emulsifiers are addition compounds of ethylene oxide and / or propylene oxide with alkylphenols, alcohols or fatty acids. The most commonly used nonionic surfactants for decades are the alkylphenol ethoxylates. However, there are environmental and toxicological concerns against the surfactant class of alkylphenol ethoxylates, so that in Germany and some other countries voluntarily dispensed with the use of Alkylphenolethoxylate. As a substitute for the Alkylphenolethoxylate predominantly alcohol ethoxylates are used.

EP-A 0 281 486 refers to biologically stabilized ungrafted skins and a method of making these skins. According to EP-A 0 281 486 Degreasing of pickled hides is carried out by adding a certain amount of emulsifier whose determined hydrophilic-lipophilic balance (HLB) is identical to the required hydrophilic-lipophilic balance (RHLB) of the natural fats contained in the skins, together with a cosurfactant in the presence of Salts at a temperature above the melting point of the fats. According to Examples 2, 4 and 6, a mixture of emulsifier and cosurfactant in an amount of about 4 wt .-% is used for degreasing, wherein the emulsifier 60 (Examples 2 and 4) and 95 (Example 6) parts of the mixture accounts.

Poré (Ind. Ciur, 1986, 5, pages 22 to 25 ) concerns a treatise on the degreasing of pickled and pre-tanned hides. The degreasing takes place while Walkung a mixture of emulsifiers and cosurfactants, with the exact mixture according to the type directed to the fats to be withdrawn. No liquor is used, but the mixture applied directly to the drained pickled skins or pimpled skins. In this case, a saturation, whereby the hydrophobic portion of the emulsifiers comes into contact with the fats in order to promote the emulsification during rinsing. Following degreasing, rinse the pickled skins with a saline solution in a short liquor. According to the disclosed work schedule, the degreasing without liquor is carried out with 2 to 4% of a suitable emulsifier. The suitable emulsifier depends on the type of fat of the skins to be degreased.

DE-A 100 05 669 relates to a process for degreasing hides in which pickled hides are degreased by treatment with a nonionic surfactant comprising an adduct of 4 to 16 moles of ethylene oxide with a C ₁₀ to C ₁₆ fatty alcohol. The surfactant is used in a concentration of 10 to 50 g / l liquor.

WO 00/12660 relates to a method for increasing the efficiency of surfactants, wherein surfactant mixtures are used, which additionally contain block copolymers with a water-soluble block A and a water-insoluble block B as an additive (efficiency booster). About the amount of surfactant or to surfactant and additive are used in WO 00/12660 no statements made.

While the work done with the prior art methods is satisfactory in removing fats from animal hides and other substrates, it is desirable to provide compositions and methods whereby the degreasing result can be further improved, especially without the use of the amount of surfactant increase, or achieve the same or better degreasing result as with the methods of the prior art when using lower amounts of surfactant.

The object of the present application is therefore to provide compositions which can be used in the removal of fats from animal skins and other substrates, as well as a method for degreasing animal skins and other substrates, wherein excellent degreasing results are achieved and, in particular, low Surfactant quantities are used. Such compositions and methods are desirable from an economical and ecological point of view.

The task is solved by
a degreasing agent for the treatment of hides, skins, pelts and other intermediates in the leather and fur production based on nonionic surfactants of the alcohol alkoxylate type, using one or more alcohol alkoxylates obtained by reacting at least one alcohol ROH with n moles of at least one Alkylene oxides are obtained per mole of alcohol ROH, wherein
R is an alkyl radical of 5 to 30 carbon atoms having a main chain which is the longest alkyl chain of the radical R having 4 to 29 carbon atoms which are in the middle of the chain, starting with the carbon atom C # 2, wherein the numbering of the carbon atom ( C # 1) bound directly to the oxygen atom adjacent to R and ending with the carbon atom ω-2, where ω is the terminal carbon atom of the main chain, including C # 2 and the carbon atom ω-2 at least one branched C ₁ - to C ₁₀ -alkyl radical;
the alkylene oxide has 2 to 6 carbon atoms
and
n is an integer value between 1 and 100,
with a polydispersity D of the individual alcohol alkoxylates or a mixture
of alcohol alkoxylates of D> 1.22,
wherein the degreasing agent contains one or more lipases and / or one or more efficiency booster composed of a block copolymer having at least one water-soluble block A and at least one water-insoluble block B.

1. a) eine Fettphase, die Fette aus Häuten, Fellen, Blößen oder weiteren Zwischenprodukten in der Leder- und Pelzherstellung enthält;
2. b) mindestens ein Alkoholalkoxylat wie vorstehend definiert,
3. c) eine wässrige Phase, und
4. d) gegebenenfalls weitere Hilfs- und Zusatzstoffe;

wobei die Grenzflächenspannung zwischen der Fettphase und der wässrigen Phase 1 mNm^-1 bis 10^-9 mNm^-1 bei einer Temperatur von 15 bis 45°C, gemessen mittels "Spinning-Drop" Tensiometrie nach B. Vonnegut, Rev. Sci. Instr. 13, 6 (1942), beträgt.Furthermore, this object is achieved by a composition comprising

1. a) a fatty phase containing fats of hides, skins, pelts or other intermediates in leather and fur manufacture;
2. b) at least one alcohol alkoxylate as defined above,
3. c) an aqueous phase, and
4. d) optionally further auxiliaries and additives;

wherein the interfacial tension between the fat phase and the aqueous phase is 1 mNm ^-1 to 10 ^-9 mNm ^-1 at a temperature of 15 to 45 ° C, measured by "spinning drop" Tensiometrie B. Vonnegut, Rev. Sci. Instr. 13, 6 (1942).

With this composition according to the invention, excellent degreasing results are achieved, with small amounts of surfactant generally being sufficient to achieve these excellent results.

The interfacial tension between the fatty phase and the aqueous phase is preferably 0.5 mNm ^-1 to 10 ^-9 mNm ^-1 , particularly preferably 10 ^-1 mNm ^-1 to 10 ^-9 mNm ^-1 . This interfacial tension is achieved at a temperature of 15 to 45 ° C, preferably 20 to 45 ° C, particularly preferably 25 to 40 ° C. The temperatures are those temperatures which are optimum for carrying out a process for removing fats from the aforementioned hides, skins, pelts or other intermediates in leather and fur manufacture.

It has been found that excellent degreasing results are achieved in the interfacial tension of the invention between the fatty phase and the aqueous phase.

fat phase

The fat content of the skin of the different animal breeds but also within the animal breeds varies considerably. Thus, bovine skins have a fat content of 0 to 2 wt .-%, goat skins a fat content of 0.5 to 3.5 wt .-% and sheep skins a fat content of 1.5 to 10 wt .-%, based on the pelt weight. The nakedness usually contains between 60 and 80 wt .-% water.

surfactants

The hides, skins, pelts and other intermediates in leather and fur production, called substrates, have fats with different compositions. It is therefore difficult to give precise information about which surfactants are most suitable in the compositions of the invention. However, the skilled person can determine the optimum surfactants by simple routine experiments.

In principle, it is possible to use anionic, cationic, amphoteric or nonionic surfactants or mixtures thereof.

Suitable anionic surfactants are C ₁₀ to C ₂₀ , preferably C ₁₂ to C ₁₆ alkyl sulfates, for example sodium dodecyl sulfate; C ₁₀ - to C ₂₀ -, preferably C ₁₂ - to C ₁₆ -alkyl polyether sulfates, for example Natriumdodecyloxypolyethoxysulfate; Alkali salts of diisooctylsulfosuccinic acid; Alkali metal salts of alkylbenzenesulfonic acids, for example sodium dodecylbenzenesulfonate, of dialkyl phosphates and of carboxylates, for example of fatty alkyl ether carboxylates.

Suitable cationic surfactants are, for example, alkyltrimethylammonium halides having alkyl chain lengths of about 8 to 12 carbon atoms and / or quaternized imidazolinium or pyridinium salts.

Suitable nonionic surfactants which are preferably used in the composition according to the invention are addition compounds of ethylene oxide and / or propylene oxide with alkylphenols, alcohols or fatty acids. The most commonly used nonionic surfactants for decades are the alkylphenol ethoxylates. In particular, the nonylphenol ethoxylate having an average of 9 EO (ethylene oxide) units was used. Also suitable and environmentally compatible as the Alkylphenolethoxylate are alcohol ethoxylates, in particular alcohol alkoxylates having alkyl chain lengths of C ₇ to C ₁₈ , preferably C ₇ to C ₁₆ , and 2 to 50, preferably 3 to 20 Oxialkylen- especially -ethylene, -propylene and / or Butylene units, or block copolymers of these units.

Particular preference is given to using nonionic surfactants having an HLB value of> 8, preferably> 10, very particularly> 12 (the HLB value was calculated ( Poré, Ind. Ciur, 1987, 4, pages 21 to 23 )).

• Laufmittel: THF 1,0 ml/min.
• Interner Standard: Toluol
• Detektor: DURATEC RI 2000
• Säule (3 Stk.): 8 x 300mm PSS SDV 105A 5 µm, 1000 A 5µ, 100 A 5µm + Vorsäule SDV 5µ (8 x 50mm)
• 20µl Einspritzvolumen
• Messtemperatur: Raumtemperatur.

As surfactants, alcohol alkoxylates are used which have a polydispersity D of generally D> 1.22, preferably> 1.25. In this case, it is possible to use a single surfactant which has the stated polydispersity or a surfactant mixture, wherein the mixture has said polydispersity. (D = polydispersity = M _w / M _n , wherein M _w and M _{n are determined} by gel permeation chromatography (GPC):
GPC conditions:

• Eluent: THF 1.0 ml / min.
• Internal standard: toluene
• Detector: DURATEC RI 2000
• Column (3 pcs.): 8 x 300mm PSS SDV 105A 5μm, 1000A 5μ, 100A 5μm + guard column SDV 5μ (8 x 50mm)
• 20μl injection volume
• Measuring temperature: room temperature.

• R ein Alkylrest mit 5 bis 30 Kohlenstoffatomen ist, der eine Hauptkette, die die längste Alkylkette des Rests R ist, mit 4 bis 29 Kohlenstoffatomen aufweist, die in der Kettenmitte, beginnend mit dem Kohlenstoffatom C2, wobei die Nummerierung von dem Kohlenstoffatom (C1) ausgeht, das direkt an das dem Rest R benachbarte Sauerstoffatom gebunden ist, und endend mit dem Kohlenstoffatom ω-2, wobei ω das endständige Kohlenstoffatom der Hauptkette ist, wobei C2 und das Kohlenstoffatom ω-2 eingeschlossen sind, mit mindestens einem C₁- bis C₁₀-Alkylrest verzweigt ist;
• das Alkylenoxid 2 bis 6 Kohlenstoffatome aufweist, und
• n ein Wert zwischen 1 und 100 ist,

mit einer Polydispersität D der einzelnen Alkoholalkoxylate oder einer Mischung von Alkoholalkoxylaten von >1,22, bevorzugt >1,25.Nonionic surfactants used in the composition according to the invention are alcohol alkoxylates which are obtained by reacting at least one alcohol ROH with n moles of at least one alkylene oxide per mole of alcohol ROH, in which

• R is an alkyl radical of 5 to 30 carbon atoms which has a main chain which is the longest alkyl chain of the radical R having 4 to 29 carbon atoms which are in the middle of the chain starting with the carbon atom C2, the numbering of the carbon atom (C1) which is bonded directly to the oxygen atom adjacent to the radical R and ending with the carbon atom ω-2, where ω is the terminal carbon atom of the main chain, wherein C2 and the carbon atom ω-2 are included, with at least one C ₁ - to Branched C ₁₀ alkyl;
• the alkylene oxide has 2 to 6 carbon atoms, and
• n is a value between 1 and 100,

with a polydispersity D of the individual alcohol alkoxylates or a mixture of alcohol alkoxylates of> 1.22, preferably> 1.25.

Such so-called Guerbet alcohol alkoxylates and their use as degreasing agents are in the non-prepublished application with the file number: PCT / EP02 / 07245 entitled "Leather degreaser". Particular preference is given to Guerbet alcohol alkoxylates based on 2-propylheptanol, in particular those containing both ethylene oxide units and propylene oxide units, such Guerbet alcohol alkoxylates which are first alkoxylated with propylene oxide and then with ethylene oxide in block mode, are very particularly preferred.

N in the alcohol alkoxylates mentioned is particularly preferably 1 to 50, very particularly preferably 1 to 30.

A particular advantage of the composition according to the invention is that excellent degreasing results are achieved even at low surfactant application rates. Thus, the surfactants in the compositions of the invention in an amount of generally> 0 parts by weight to 500 parts by weight, preferably> 0 parts by weight to 100 parts by weight, particularly preferably> 0 parts by weight to 50 parts by weight, very particularly preferably> 0 to 25 parts by weight, based on the mass of the fatty phase used.

The amounts of the components in the compositions according to the invention are given in parts by weight in the present application. In practice, the tanner uses partial wt .-% for such information.

Aqueous phase

In addition to the fat phase and the at least one surfactant, the composition according to the invention contains an aqueous phase containing water. This may additionally contain at least one salt selected from alkali and alkaline earth salts. Particularly preferred salts are sodium chloride, potassium chloride, sodium formate and sodium acetate. Very particular preference is given to using sodium chloride.

The salt or salts are in the aqueous phase - if they are contained in the aqueous phase - in an amount of generally> 0 parts by weight to 1000 parts by weight, preferably> 0 parts by weight to 500 wt ., Parts, particularly preferably> 0 parts by weight to 200 parts by weight, based on the fatty phase before.

Furthermore, the aqueous phase may contain further compounds which influence the hydrophilic-lipophilic balance, in particular the aqueous phase. Such compounds are for. For example, hydrophilic organic compounds such as short chain alcohols or acids, e.g. Alcohols having 1 to 6, preferably 1 to 3 carbon atoms, such as ethanol, or acids having 1 to 6, preferably 1 to 3 carbon atoms in the alkyl radical of the acid, such as acetic acid, or polyacids, such as glycerol, polyglycerol, polyvinyl alcohols and sorbitol. Other compounds which affect the hydrophilicity or hydrophobicity of the aqueous phase are e.g. hydrophobic organic compounds, such as longer-chain fatty alcohols or fatty acids, preferably fatty alcohols or fatty acids having 7 to 50, particularly preferably 10 to 30 carbon atoms in the alkyl or alkenyl radical of the fatty alcohols or fatty acids.

These further compounds, which influence the hydrophilic-lipophilic balance, in particular the aqueous phase, when present in the aqueous phase, are present in an amount of generally> 0 parts by weight to 1000 parts by weight, preferably> 0 Parts by weight to 500 parts by weight, more preferably> 0 parts by weight to 200 parts by weight, based on the fatty phase used.

These further compounds exert a significant effect on the interfacial tension in the compositions of the invention. This must be taken into account when selecting the surfactant. The determination of combinations of surfactants and other compounds which are suitable for the compositions according to the invention and which influence the hydrophilicity or the hydrophobicity of the aqueous phase can be carried out in a few routine experiments familiar to the person skilled in the art.

Auxiliaries and additives

Furthermore, the compositions of the invention may contain other auxiliaries and additives.

Suitable further auxiliaries and additives are preferably selected from the group consisting of efficiency boosters and lipases.

Suitable efficiency boosters are known to the person skilled in the art. Efficiency boosters are preferably used, built up from a block copolymer having at least one water-soluble block A and at least one water-insoluble block B. The block copolymers preferably have a structure according to the pattern AB, ABA or BAB. Block A is particularly preferably a polyethylene oxide and block B is a polydiene or an at least partially hydrogenated polydiene. Such efficiency boosters are eg in WO 00/12660 disclosed.

The efficiency booster, when contained in the composition according to the invention, in an amount of generally> 0 parts by weight to 250 parts by weight, preferably> 0 parts by weight to 30 parts by weight, more preferably> 0 parts by weight to 10 parts by weight, based on the fatty phase used.

Furthermore, the compositions of the invention may contain lipases. Nature, for example, builds fats up and down in many ways with the help of lipases. In the decomposition of the fats glycerol, fatty acids, mono- and diglycerides are formed, which affect the interfacial tension between the fatty phase and the aqueous phase, since they are surface-active. The fatty acids formed in the decomposition have an amphiphilic character due to their hydrophilic head group and their hydrophobic tail, as do the mono- and diglycerides formed. Assuming now that form in the decomposition of fats amphiphiles, this brings about a significant effect on the interfacial tension in the compositions of the invention, since the decomposition of a fat effectively one or more surface-active compounds.

In a further embodiment of the present invention, the compositions according to the invention therefore contain lipases which can degrade the fats contained in the composition to form surface-active compounds which exert a beneficial influence on the interfacial tension. Due to the (partial) conversion of the fat into surface-active ingredients, the amount of surfactant to be used can be considerably reduced.

The lipases, when contained in the composition of the invention, in an amount of generally> 0 to 250 parts by weight, preferably> 0 to 30 parts by weight, particularly preferably> 0 to 10 parts by weight, based to the fatty phase, used in the compositions of the invention.

When using lipases, it should be noted that the interfacial tension changes in a composition containing a given surfactant. It is thus necessary, in order to achieve optimum degreasing results, to match the optionally used lipase and the surfactants used according to the invention to one another. The appropriate combinations can be easily determined by routine experimentation by a person skilled in the art. In general, the use of lipases requires the use of e.g. higher alkoxylated alcohol alkoxylates having a degree of ethoxylation n of preferably n> 8, more preferably n> 15.

The compositions according to the invention generally have a pH of 1 to 14, preferably 2 to 12, particularly preferably 5 to 9.

1. a) eine Fettphase, die Fette aus Häuten, Fellen, Blößen oder weiteren Zwischenprodukten in der Leder- und Pelzherstellung enthält;
2. b) >0 bis 500 Gew.-Teile, bevorzugt >0 bis 100 Gew.-Teile, besonders bevorzugt >0 bis 50 Gew.-Teile, bezogen auf die Fettphase, mindestens eines Tensids, bevorzugt eines nichtionischen Tensids, besonders bevorzugt eines Alkoholalkoxylats;
3. c) >0 bis 5000 Gew.-Teile, bevorzugt >0 bis 1000 Gew.-Teile, besonders bevorzugt >0 bis 500 Gew.-Teile, bezogen auf die Fettphase, einer wässrigen Phase, enthaltend Wasser und;
   gegebenenfalls entweder
   • c1) >0 bis 1000 Gew.-Teile, bevorzugt >0 bis 500 Gew.-Teile, besonders bevorzugt >0 bis 200 Gew.-Teile, bezogen auf die Fettphase, mindestens eines Salzes, bevorzugt Natriumchlord;
     und/oder
   • c2) >0 bis 1000 Gew.-Teile, bevorzugt >0 bis 500 Gew.-Teile, besonders bevorzugt >0 bis 200 Gew.-Teile, bezogen auf die Fettphase, weitere Verbindungen, die die hydrophile-lipophile Balance, insbesondere der wässrigen Phase beinflussen, bevorzugt hydrophile organische Verbindungen wie kurzkettige Alkohole oder Säuren, z.B. Alkohole mit 1 bis 6, bevorzugt 1 bis 3 Kohlenstoffatomen, wie Ethanol, oder Säuren mit 1 bis 6, bevorzugt 1 bis 3 Kohlenstoffatomen im Alkylrest der Säure, wie Essigsäure, oder Polyakohole, wie Glycerin, Polyglycerin, Polyvinylakohole und Sorbit; oder hydrophobe organische Verbindungen wie längerkettige Fettalkohole oder Fettsäuren, z.B. Fettalkohole oder Fettsäuren mit 7 bis 50, besonders bevorzugt 10 bis 30 Kohlenstoffatomen im Alkyl- oder Alkenylrest der Fettalkohole oder Fettsäuren,
4. d) >0 bis 250 Gew.-Teile, bevorzugt >0 bis 30 Gew.-Teile, besonders bevorzugt >0 bis 10 Gew.-Teile, bezogen auf die Fettphase, weitere Hilfs- und Zusatzstoffe, bevorzugt Efficiency Booster und/oder Lipasen.

In a particularly preferred embodiment, the compositions according to the invention contain the following components:

1. a) a fatty phase containing fats of hides, skins, pelts or other intermediates in leather and fur manufacture;
2. b)> 0 to 500 parts by weight, preferably> 0 to 100 parts by weight, particularly preferably> 0 to 50 parts by weight, based on the fatty phase, of at least one surfactant, preferably a nonionic surfactant, more preferably an alcohol alkoxylate ;
3. c)> 0 to 5000 parts by weight, preferably> 0 to 1000 parts by weight, particularly preferably> 0 to 500 parts by weight, based on the fatty phase, of an aqueous phase containing water and;
   if appropriate, either
   • c1)> 0 to 1000 parts by weight, preferably> 0 to 500 parts by weight, more preferably> 0 to 200 parts by weight, based on the fatty phase, of at least one salt, preferably sodium chloride;
     and or
   • c2)> 0 to 1000 parts by weight, preferably> 0 to 500 parts by weight, particularly preferably> 0 to 200 parts by weight, based on the fatty phase, of further compounds containing the hydrophilic-lipophilic balance, in particular the aqueous Phase influence, preferably hydrophilic organic compounds such as short-chain alcohols or acids, for example alcohols having 1 to 6, preferably 1 to 3 carbon atoms, such as ethanol, or acids having 1 to 6, preferably 1 to 3 carbon atoms in the alkyl radical of the acid, such as acetic acid, or Polyacels such as glycerin, polyglycerin, polyvinyl alcohols and sorbitol; or hydrophobic organic compounds such as relatively long-chain fatty alcohols or fatty acids, for example fatty alcohols or fatty acids having 7 to 50, particularly preferably 10 to 30, carbon atoms in the alkyl or alkenyl radical of the fatty alcohols or fatty acids,
4. d)> 0 to 250 parts by weight, preferably> 0 to 30 parts by weight, particularly preferably> 0 to 10 parts by weight, based on the fatty phase, of further auxiliaries and additives, preferably efficiency boosters and / or lipases ,

These compositions of the invention are excellent for degreasing hides, skins, pelts and / or other intermediates in the leather and Fur production or wool suitable. Preferably, the substrates mentioned are used in uncoiled form.

1. a) in Kontaktbringen der zu entfettenden Substrate mit einem Entfettungsmittel, enthaltend mindestens ein Alkoholalkoxylat gemäß der vorliegenden Anmeldung und eine wässrige Phase, die Wasser, gegebenenfalls mindestens ein Salz und gegebenenfalls weitere Verbindungen, die die hydrophile-lipophile Balance, insbesondere der wässrigen Phase beinflussen, enthält, bei einer Temperatur von 15 bis 45°C;
2. b) Ausbildung einer Zusammensetzung enthaltend eine Fettphase, die Fette aus Häuten, Fellen, Blößen oder weiteren Zwischenprodukten in der Leder- und Pelzherstellung enthält, das mindestens eine Tensid und die wässrige Phase, die Wasser und gegebenenfalls mindestens ein Salz und gegebenenfalls weitere Verbindungen, die die hydrophile-lipophile Balance, insbesondere der wässrigen Phase beinflussen, enthält und gegebenenfalls weitere Hilfs- und Zusatzstoffe, wobei die Grenzflächenspannung zwischen der Fettphase und der wässrigen Phase 1 mNm^-1 bis 10^-9 mNm^-1, gemessen mittels "Spinning-Drop" Tensiometrie nach B. Vonnegut, Rev. Sci. Instr. 13, 6 (1942 ), beträgt ((An-)Lösen des Fettes);
3. c) Erhöhung der Grenzflächenspannung zwischen der Fettphase und der wässrigen Phase der Zusammensetzung auf eine Grenzflächenspannung von >1 mNm^-1, gemessen mittels "Spinning-Drop" Tensiometrie nach B. Vonnegut, Rev. Sci. Instr. 13, 6 (1942 ), wobei eine Fettphase, eine wässrige Phase und eine wässrige Tensidphase gebildet werden (Abtransport des Fettes).

Another object of the present invention is a process for the removal of fats from substrates selected from the group consisting of hides, skins, pelts, other intermediates in the leather and fur manufacturing, comprising the following steps:

1. a) contacting the degreasing substrates with a degreasing agent containing at least one alcohol alkoxylate according to the present application and an aqueous phase, the water, optionally at least one salt and optionally further compounds which influence the hydrophilic-lipophilic balance, in particular the aqueous phase, contains, at a temperature of 15 to 45 ° C;
2. b) forming a composition containing a fatty phase containing fats of hides, skins, pelts or other intermediates in the leather and fur manufacturing, the at least one surfactant and the aqueous phase, the water and optionally at least one salt and optionally other compounds, the the hydrophilic-lipophilic balance, in particular the aqueous phase influence, contains and optionally other auxiliaries and additives, wherein the interfacial tension between the fat phase and the aqueous phase 1 mNm ^-1 to 10 ^-9 mNm ^-1 , measured by "spinning drop" Tensiometry after B. Vonnegut, Rev. Sci. Instr. 13, 6 (1942 ), is ((on) dissolving the fat);
3. c) Increasing the interfacial tension between the fat phase and the aqueous phase of the composition to an interfacial tension of> 1 mNm ^-1 , measured by means of "spinning drop" tensiometry B. Vonnegut, Rev. Sci. Instr. 13, 6 (1942 ), whereby a fat phase, an aqueous phase and an aqueous surfactant phase are formed (removal of the fat).

With the method according to the invention excellent degreasing results are achieved and further is a simple and complete separation of the obtained from the hides, skins, pelts, other intermediates in the leather and fur production (substrates) fat possible.

If appropriate, further steps can follow steps a) to c). For example, a rinsing step (step d) subsequent to step c) is conceivable in which rinsing is preferably carried out with a surfactant-containing mixture. The exact composition of the surfactant-containing mixture used in the rinsing step and the performance of the rinsing step is known to the person skilled in the art. The surfactants used are preferably the abovementioned surfactants. The rinsing step can be carried out once or optionally repeated once or several times.

It is alternatively also possible to repeat steps a) to c) and optionally d) of the degreasing process according to the invention once or several times. This is particularly preferred for substrates with high fat contents. The repeated execution of steps a) to c) and optionally d) is carried out under conditions known to those skilled in the art.

The individual steps of leather or fur manufacturing such as switches, ashes, defilement and crevices, stains, pimples, tanning, wilting, sorting by quality criteria, folding, neutralization, filling, dyeing, fats, drying, studs and trimming and in these steps preferred reaction conditions and starting materials are known to the person skilled in the art.

The degreasing of the substrates mentioned in accordance with the process according to the invention can take place in different process stages in leather and fur production.

Preference is given to degreasing the pickled substrates, since then a particularly good and complete degreasing is achieved.

Step a)

The subsequent contacting of the degreasing substrates with a degreasing agent (step a)) may be carried out in any suitable and suitable apparatus known to those skilled in the art, e.g. in a tannery, done.

Step a) takes place at a temperature of 15 to 45 ° C, preferably 20 to 45 ° C, particularly preferably 25 to 45 ° C. In general, an increase in temperature leads to an increase in the degree of degreasing.

The duration of step a) of the process according to the invention is generally 0.5 hours to 10 hours, preferably 0.5 hours to 5 hours, more preferably 0.5 hours to 3 hours.

The surfactants used in the process according to the invention, the amount of surfactants used, the amount and type of salt optionally used, the amount and type of optionally used further compounds which influence the hydrophilic-lipophilic balance, in particular the aqueous phase, and the auxiliary used - And additives and their amount correspond to the statements made with respect to the composition of the invention.

The degreasing process according to the invention (step a)) can be carried out in the liquor or without a liquor, that is, only with the inner liquor of the nakedness. If the process is carried out without a liquor, there is generally an addition of the degreasing agent to the substrates to be degreased and subsequent casting.

Step b)

The interfacial tension of the composition formed in step b) between the fatty phase and the aqueous phase is preferably 0.5 mNm ^-1 to 10 ^-9 mNm ^-1 , particularly preferably 10 ^-1 mNm ^-1 to 10 ^-9 mNm ^-1 . This interfacial tension is particularly preferred at a temperature of 15 to 45 ° C, preferably 20 to 45 ° C 25 to 40 ° C reached. The temperatures are those temperatures which are optimum for carrying out a process for removing fats from the aforementioned hides, skins, pelts or other intermediates in leather and fur manufacture.

Step c)

The increase in interfacial tension between the fat phase and the aqueous phase of the composition can be accomplished in a number of ways. Thus, it is possible, on the one hand, to change the temperature of the composition formed in step b) or to lower the salt concentration in the composition formed in step b) or amount of the further compounds which may be used, the hydrophilic-lipophilic balance, in particular the aqueous phase influence or modify in step c) those compounds which influence the hydrophilic-lipophilic balance, in particular the aqueous phase, and thus to change the polarity of the aqueous phase.

In a preferred embodiment, the interfacial tension of the composition formed in step b) is increased by lowering the concentration of the salt present in the aqueous phase if the aqueous phase contains at least one salt in step a).

The lowering of the concentration of the salt present in the aqueous phase is most easily achieved by dilution with water. The salt concentration is generally reduced to <5 parts by weight to <3 parts by weight, preferably <2 parts by weight.

In a further preferred embodiment, the interfacial tension of the composition formed in step b) is increased by changing the temperature of the composition formed in step b).

It is also possible to increase the interfacial tension of the composition formed in step b) by a combination of several of the said procedures increase. For example, a temperature change may occur simultaneously with a lowering of the salt concentration of the composition.

• die Fettphase enthält solubilisiertes Fett und gegebenenfalls geinge Mengen darin gelöster hydrophober Tensidkomponenten,
• die wässrige Phase enthält gegebenenfalls mindestens ein Salz und und gegebenenfalls weitere Verbindungen, die die hydrophile-lipophile Balance, insbesondere der wässrigen Phase beinflussen, sowie gegebenenfalls geringe Mengen in der wässrigen Phase gelöster hydrophiler Tensidkomponenten, und
• die wässrige Tensidphase enthält den Hauptteil der Tensidkomponenten und geringe Mengen an Fett.

The fatty phase obtained can be separated according to methods known to the person skilled in the art. The separation takes place for example in a phase separator or by centrifugation. This generally produces three phases: a fatty phase, an aqueous phase and an aqueous surfactant phase:

• the fatty phase contains solubilized fat and optionally some amounts of hydrophobic surfactant components dissolved therein,
• the aqueous phase optionally contains at least one salt and optionally further compounds which influence the hydrophilic-lipophilic balance, in particular of the aqueous phase, and optionally small amounts of hydrophilic surfactant components dissolved in the aqueous phase, and
• the aqueous surfactant phase contains most of the surfactant components and small amounts of fat.

The aqueous surfactant phase can be used again in step a) of the process according to the invention. Thus, an economic and ecological implementation of the method according to the invention is possible because the amount of surfactant to be used can be further reduced by this recycling.

With the method according to the invention or the compositions according to the invention, efficiencies (difference in fat content before degreasing and after degreasing) x 100 / (fat content before degreasing) of ≥ 50%, preferably ≥ 60%, particularly preferably ≥ 70, can be achieved in the leather degreasing % be achieved.

Another object of the present invention is the use of the composition of the invention in the removal of fats from substrates selected from the group consisting of skins, fats, pelts and other intermediates in leather and fur manufacture.

The inventive use excellent degreasing results can be achieved.

With the aid of the alcohol alkoxylates or alcohol alkoxylate mixtures according to the present application, emulsions with high emulsion stability, ie fat-carrying capacity, are obtained which allow excellent removal of the fat (step c)) so that subsequent deposition of the fat dissolved out of the nakedness in step b) is avoided becomes.

Such so-called Guerbet alcohol alkoxylates and their use as degreasing agents are in the non-prepublished application with the file number: PCT / EP02 / 07245 entitled "Leather degreaser". Compared to the not previously published application with the file number: PCT / EP02 / 07245 It has been found, with the title "leather degreaser", that alcohol alkoxylates having a high polydispersity of a single alcohol alkoxylate or a mixture of alcohol alkoxylates of D> 1.22, preferably D> 1.25, are particularly effective. Particular preference is given to Guerbet alcohol alkoxylates based on 2-propylheptanol, in particular those containing both ethylene oxide units and propylene oxide units, such Guerbet alcohol alkoxylates which are first alkoxylated with propylene oxide and then with ethylene oxide in block mode, are very particularly preferred.

Preferred embodiments of the degreasing agents and of components in the degreasing agents are in PCT / EP02 / 07245 disclosed.

The degreasing agents according to the invention contain, in addition to the alcohol alkoxylates according to the present application, one or more lipases and / or one or more efficiency boosters. Suitable Lipases and Efficiency Booster are called projecting.

The alcohol alkoxylates contained in the abovementioned degreasing agents are contained in degreased substrates selected from the group consisting of hides, skins, pelts and other intermediates in leather and fur manufacture.

The alcohol alkoxylates are present in the degreased substrates in an amount of generally> 0 to 3 parts by weight, preferably> 0 to 2 parts by weight, more preferably> 0 to 1 parts by weight, based on the defatted pelt ,

The following examples further illustrate the invention.

Examples

Degreasing experiments were carried out on sheepskins, which are pickled and washed. In each case about 2 kg of nakedness at a temperature of 30 ° C were degreased.

• konstante Temperatur, T = 30 °C
• erste kurze Flotte von 30 Gew.-Teile Wasser im ersten Entfettungsschritt inklusive ca. 8 Gew.-Teile Salz mit Tensid gemäß den Angaben in Tabelle 1 (1. Dosierung)
• Verlängerung der ersten Flotte mit 120 Gew.-Teile Wasser, wodurch die Salzkonzentration auf ca. 2 Gew.-Teile erniedrigt wird
• zweite lange Flotte mit 100 Gew.-Teile Wasser und Tensid gemäß den Angaben in Tabelle 1 (zweite Dosierung)

The main parameters of the degreasing tests are listed below:

• constant temperature, T = 30 ° C
• first short liquor of 30 parts by weight of water in the first degreasing step, including about 8 parts by weight of salt with surfactant, as indicated in Table 1 (1st dosage)
• Extension of the first liquor with 120 parts by weight of water, whereby the salt concentration is reduced to about 2 parts by weight
• second long liquor containing 100 parts by weight of water and surfactant as indicated in Table 1 (second dosage)

The attached Table 2 lists the degreaser formulation used in the process according to the examples.

• Lutensol AP 9 (Nonylphenolethoxylat mit im Mittel 9 Ethylenoxid-(EO)-Einheiten, D = 1,08)
• Eusapon LD 6031 (verzweigter C10-Alkoholalkoxylat mit zuerst im Mittel 1,5 Propylenoxid-(PO)- und dann 6 EO-Einheiten, D = 1,23)
• Lutensol XL 60 (verzweigter C10-Alkoholalkoxylat mit zuerst im Mittel 1,2 Propylenoxid-(PO)- und dann 6 EO-Einheiten, D = 1,06)
• Lutensol AO4 (C13C15-Oxoalkoholethoxylat mit im Mittel 4 EO-Einheiten, D = 1,07)
• Lutensol AO7 (C13C15-Oxoalkoholethoxylat mit im Mittel 7 EO-Einheiten, D = 1,10)
• Lutensol AO11 (C13C15-Oxoalkoholethoxylat mit im Mittel 11 EO-Einheiten, D = 1,12)
• PIBA 1000 + 11 EO (Polyisobutylenamin mit 11 EO)

The following surfactants were used:

• Lutensol AP 9 (nonylphenol ethoxylate with an average of 9 ethylene oxide (EO) units, D = 1.08)
• Eusapon LD 6031 (branched C10 alcohol alkoxylate with first average 1.5 propylene oxide (PO) and then 6 EO units, D = 1.23)
• Lutensol XL 60 (branched C10-alcohol alkoxylate with first average of 1,2 propylene oxide (PO) - and then 6 EO units, D = 1,06)
• Lutensol AO4 (C13C15 oxo alcohol ethoxylate with an average of 4 EO units, D = 1.07)
• Lutensol AO7 (C13C15 oxo alcohol ethoxylate with an average of 7 EO units, D = 1.10)
• Lutensol AO11 (C13C15 oxo alcohol ethoxylate with an average of 11 EO units, D = 1.12)
• PIBA 1000 + 11 EO (polyisobutyleneamine with 11 EO)

• Laufmittel: THF 1,0 ml/min.
• Interner Standard: Toluol
• Detektor: DURATEC RI 2000
• Säule (3 Stk.): 8 x 300mm PSS SDV 105A 5 µm, 1000 A 5µ, 100 A 5µm + Vorsäule SDV 5µm (8 x 50mm)
• 20µl Einspritzvolumen
• Messtemperatur: Raumtemperatur

D = polydispersity = M _w / M _n , where M _w and M _{n are determined} by gel permeation chromatography (GPC):
GPC conditions:

• Eluent: THF 1.0 ml / min.
• Internal standard: toluene
• Detector: DURATEC RI 2000
• Column (3 pcs.): 8 x 300mm PSS SDV 105A 5μm, 1000A 5μ, 100A 5μm + precalculator SDV 5μm (8 x 50mm)
• 20μl injection volume
• Measuring temperature: room temperature

1. 1 = exzellent entfettet (Nacken und Flämen fettfrei)
2. 2 = sehr gut entfettet (Nacken fettfrei, Flämen leicht fettig)
3. 3 = gut entfettet (Nacken und Flämen leicht fettig)
4. 4 = befriedigend entfettet (Nacken und Flämen fettig)
5. 5 = schlecht entfettet ("Fettspots")
6. 6 = sehr schlecht entfettet ("Fettspots" und teilweise keine Entfettung)

*) = erfindungsgemäß, jedoch erfordert der Einsatz von Lipasen im Allgemeinen den Einsatz von z.B. höher alkoxylierten Alkoholalkoxylaten mit einem Ethoxylierungsgrad n von bevorzugt n>8, besonders bevorzugt n > 15
**) = nicht erfindungsgemäß Table 1 below shows the results of the degreasing tests. <i> Table 1: Degreasing results </ i> attempt degreasing dosage Fat content of the liquor Interfacial tension of the short first fleet leather assessment 1.
[%] Second
[%] 1. [%]
150% water 2. [%]
100% water [mNm ^-1 ] V1 Lutensol® AP9 1 2 2 2 1.19 2 V2 Lutensol® AO7 1 2 3 2 1.26 2 V3 Lutensol® AO11 1 2 2 2 1.8 2 V4 *) Eusapon® LD 6031 Lipase LBR1 1
0.1 2
0 1 2 1.2 4 E1 **) Lutensol® XL60 1 2 1 2 0.83 2 E2 Eusapon® LD 6031 1 2 2 3 0.37 1 E3 Eusapon® LD 6031 0.8 1.6 2 3 0.25 1 E4 **) C ₁₀ -OH with 1.5 PO and 20 EO + lipase LBR1 1
0.1 2
0 2 3 0.09 1 E5 **) Lutensol® AO7 + (PIBA 1000 + 11EO) 0.7
0.1 2
0 2 3 0.08 2 E6 2nd Fleet (split) from E2 in 1st Fleet + Eusapon LD 6031 in 2nd Fleet - 2 3 1 0.009 1 1) dosage of the surfactant in wt .-%, based on the amount of water used; 1. = dosage in the first short liquor, 2. = dosage in the second long liquor;
2) Fat content of the liquor in% by weight, based on the amount of water used
3) the degreased pelts were visually evaluated:

1. 1 = excellent degreased (neck and veins fat-free)
2. 2 = very good degreased (neck free of fat, greases slightly greasy)
3. 3 = well degreased (neck and flakes slightly greasy)
4. 4 = satisfactorily degreased (neck and greases greasy)
5. 5 = badly degreased ("fat spots")
6. 6 = very poorly degreased ("grease spots" and sometimes no degreasing)

*) = According to the invention, however, the use of lipases generally requires the use of, for example, higher alkoxylated alcohol alkoxylates having a degree of ethoxylation n of preferably n> 8, particularly preferably n> 15
**) = not according to the invention

Evaluation of the results of the degreasing tests:

V1 to V3 give well-degreased leather with a high surface tension in the first fleet. In comparison, E1 with lower interfacial tension leads to a better result. The combination of (ultra) low interfacial tension and the use of surfactants or surfactant mixtures with a broad molecular weight distribution, the result improves again (E2) or allows a further reduction of the amount of surfactant used (E3). Due to the broader molecular weight distribution, a better emulsion stability of the diluted 1st liquor and the 2nd liquor is achieved for the removal of the fat, ie the fat-carrying stability is increased, whereby an improved removal of the fat is achieved.

• Der Einsatz von Efficieny-booster (E3) führt bei reduzierter Tensidmenge zu dem selben Ergebnis wie V3.
• Erwärmen der 2. Flotte aus E2 auf 65°C führt zu einer Aufspaltung der Emulsion in 3 Phasen. Die Verwendung der wässrigen tensidreichen Phase als 1. Flotte in E6 führt zu dem selben sehr guten Ergebnis wie E2 oder E3. Es kann also ein Drittel der Tensidmenge eingespart werden.

By using a lipase (V4), the very good result of E2 becomes inferior, explained by the formation of hydrophobic surfactant components from the fats and thus a shift in the hydrophilic-lipophilic balance of the phases, which leads to an increase in the interfacial tension results in a worse degreasing result. If, however, as described in E4, a higher ethoxylated alkoxylate is used as the surfactant, again a very low interfacial tension is obtained, which leads to a very good degreasing result.

• The use of Efficieny-booster (E3) leads to the same result as V3 with a reduced amount of surfactant.
• Heating the 2nd liquor from E2 to 65 ° C leads to a splitting of the emulsion into 3 phases. The use of the aqueous surfactant-rich phase as the first liquor in E6 leads to the same very good result as E2 or E3. So it can be saved one third of the amount of surfactant.

Measurement of interfacial tension by means of spinning-drop tensiometry:

The principle of "spinning-drop" tensiometry was developed by Vonnegut [1] in 1942 and is one of the classical measurement methods in which the interfacial tension is derived from the geometric shape of a droplet located in the outer field. For this purpose, the two phases to be examined are brought into a capillary rotating about the horizontal axis. Under the influence of centrifugal force and interfacial tension, the lighter phase in equilibrium takes the form of a droplet stretched along the axis of rotation, the diameter of which is measured as a function of rotational speed.

zwischen diesen beiden Phasen zu bestimmen. Berechnet wurden die Grenzflächenspannungen nach Vonnegut [1]. Er betrachtete den Tropfen als Zylinder mit einem Radius r, einer Länge 1 und halbkugelförmigen Enden. Für Tropfen, bei denen 1 >> r, kann danach die Grenzflächenspannung durch

berechnet werden. Dabei ist ω die Winkelgeschwindigkeit und (ρ₁ - ρ₂) die Dichtedifferenz der beiden Phasen [4, 5].In the investigations carried out here, the interfacial tensions were measured with a Krüss SITE 04 "spinning-drop" tensiometer. This tensiometer type was reported by Cayias et al. [2] and modified by Burkowsky and Marx [3]. It allows to measure interfacial tensions in a range of 10 ¹ <6 / mNm ^-1 / <10 ^-4 . It consists of a thermostatable glass capillary, which can rotate around its longitudinal axis with a maximum of 10,000 rpm. At the respective measurement temperature, after adjustment of the phase equilibrium, the fat phase was injected into the rotating capillary, which was filled with the water phase, to the interfacial tension

between these two phases. The interfacial tensions according to Vonnegut were calculated [1]. He considered the drop as a cylinder with a radius r, a length 1 and hemispherical ends. For drops in which 1 >> r, thereafter, the interfacial tension through

be calculated. Here, ω is the angular velocity and (ρ ₁ -ρ ₂ ) the density difference of the two phases [4, 5].

The statistical error in the "spinning drop" measurements is only about 1-2%. However, the systematic error caused by temperature fluctuations or possible contamination of the sample during stripping lies in the range of up to 10% and thus provides the major part.

The temperature inaccuracy is approx. ± 0.1 ° C.

literature

1. [1] B. Vonnegut, Rev. Sci. Instr. 13, 6 (1942 ).
2. [2] JL Cayias, RS Schechter, and WH Wade, in: Adsorption at Interfaces, ed. By KL Mittal, ACS Symposium Series Vol. 8, Washington, DC, 1975 ,
3. [3] M. Burkowsky and C. Marx, Tenside Detergents 15 5, 247 (1978 ).
4. [4] T. Sottmann and R. Strey, Ber. Bunsenges. Phys. Chem. 100, 3, 237 (1996 )
5. [5] T. Sottman, Dissertation, Göttingen (1998 ).

Table 2: Degreasing recipe Parts by weight component Temperature [° C] Relationship with water Time [min] PH value 1. degreasing 30 water 30 8th salt 1.5 soda x surfactant 10 Skins to it 60 120 Water (dilution) 30 10 4,5-5 Fleet off To wash 200 water 30 10 Fleet off 10 2. degreasing 100 water 30 x surfactant 60 Fleet off 10 Washing (2x) 200 water 30 10 Fleet off Tanning (pimples) 40 water 20 7 salt 10 + 1.0 formic acid 1:10 15 2.5 + 0.5 sulfuric acid 1:10 120 + 6 Chromitan® FM 120 + 0.45 Neutrigan® MO / MON on box, wilt, fold, finish O.N. 4.0

Subsequent to the steps listed above, retanning, dyeing and greasing and subsequent drying are carried out by methods known to the person skilled in the art. After drying, the assessment is carried out.

Claims (11)

1. Degreasing agent for the treatment of hides, skins, pelts and other intermediate products in leather and fur production on the basis of non-ionic surfactants of the alcohol alkoxylate type, wherein one or more alcohol alkoxylates are used which are obtained by reacting at least one alcohol ROH with n mol of at least one alkylene oxide per mol of alcohol ROH, wherein

   - R is an alkyl group having from 5 to 30 carbon atoms and having a main chain, which is the longest alkyl chain of the R group, having from 4 to 29 carbon atoms, which is in the middle of the chain, starting with the carbon atom C#2, wherein the numbering starts from the carbon atom (C#1), directly attached to the oxygen atom adjacent to the R group and ending with the carbon atom ω-2, wherein ω is the terminal carbon atom of the main chain, wherein C#2 and the carbon atom ω-2 is included, branched with at least one C₁ - to C₁₀ alkyl group;

   - the alkylene oxide has 2 to 6 carbon atoms
   and

   - n is an integer value between 1 and 100,

   having a polydispersity D of the individual alcohol alkoxylate or a mixture of alcohol alkoxylates of D >1.22,
   characterised in that the degreasing agent contains one or a plurality of lipases and/or one or a plurality of efficiency boosters composed of a block copolymer having at least one water-soluble block A and at least one water-insoluble block B.
2. Composition containing

   a) a fat phase containing fats from hides, skins, pelts or other intermediate products used in the production of leather and fur;

   b) at least one alcohol alkoxylate as defined in claim 1;

   c) an aqueous phase, and

   d) optionally, other auxiliary substances and additives;

   wherein the interfacial tension between the fat phase and the aqueous phase is 1 mNm^-1 to 10^-9 mNm^-1 at a temperature of 15 to 45°C, measured by means of spinning drop tensiometry according to B. Vonnegut, Rev. Sci. Instr. 13, 6 (1942).
3. Composition according to claim 2, characterised in that the interfacial tension is 0.5 mNm^-1 to 10^-9 mNm^-1, preferably 10^-1 to 10^-9 mNm^-1, measured by means of spinning drop tensiometry.
4. Composition according to claim 2 or 3, characterised in that the surfactants are used in a concentration of >0 parts by weight to 500 parts by weight, preferably >0 parts by weight to 100 parts by weight, particularly preferably >0 parts by weight to 50 parts by weight, based on the amount of the fat phase.
5. Composition according to any one of claims 2 to 4, characterised in that the aqueous phase optionally contains at least one salt selected from alkali metal and alkaline earth metal salts and/or further compounds which influence the hydrophilic-lipophilic balance, in particular the aqueous phase.
6. Composition according to any one of claims 2 to 5, characterised in that the auxiliary substances and additives are selected from the group consisting of efficiency boosters composed of a block copolymer having at least one water-soluble block A and at least one water-insoluble block B and lipases.
7. Method for removing fats from substrates selected from the group consisting of hides, skins, pelts and other intermediate products in the production of leather and fur comprising the following steps:

   a) bringing the substrates to be degreased into contact with a degreasing agent containing at least one alcohol alkoxylate according to claim 1 and an aqueous phase containing water, optionally at least one salt and optionally further compounds which influence the hydrophilic-lipophilic balance, in particular aqueous phase, at a temperature of 15 to 45°C;

   b) formation of a composition comprising a fat phase containing fats from hides, skins, pelts or other intermediate products in the production of leather and fur, wherein the fat phase contains at least one surfactant and the aqueous phase contains water and optionally at least one salt and optionally further compounds which influence the hydrophilic-lipophilic balance, in particular the aqueous phase, and optionally further auxiliary substances and additives, wherein the interfacial tension between the fat phase and the aqueous phase is 1 mNm^-1 to 10^-9 mNm^-1, measured by means of spinning drop tensiometry according to B. Vonnegut, Rev. Sci. Instrument 13, 6 (1942);

   c) increase of the interfacial tension between the fat phase and the aqueous phase of the composition, preferably to an interfacial tension of >1 mNm^-1, measured by spinning drop tensiometry according to B. Vonnegut, Rev. Sci. Instr. 13, 6 (1942), in which a fat phase, an aqueous phase and an aqueous surfactant phase are formed.
8. Method according to claim 7, characterised in that the increase in the interfacial tension between the fat phase and the aqueous phase of the composition is achieved by changing the temperature of the composition formed in step b), lowering the concentration of the salt optionally present in the aqueous phase, changing the quantity of further compounds optionally used which influence the hydrophilic-lipophilic balance, in particular the aqueous phase, and/or adding compounds which influence the hydrophilic-lipophilic balance, in particular the aqueous phase, in step c).
9. Method according to claim 7 or 8, characterised in that the surfactants are used in a concentration of >0 parts by weight to 500 parts by weight, preferably >0 parts by weight to 100 parts by weight, particularly preferably >0 parts by weight to 50 parts by weight, based on the amount of the fat phase.
10. A method according to any of claims 7 to 9, characterised in that the auxiliary substances and additives are selected from the group consisting of efficiency boosters composed of a block copolymer having at least one water-soluble block A and at least one water-insoluble block B and lipases.
11. Use of a composition according to any one of claims 2 to 6 in the removal of fats from substrates selected from the group consisting of hides, skins, pelts and other intermediate products in the production of leather and fur.