DE19736309A1 - Leather, used for clothes, shoes, furniture covers and automobile interiors - Google Patents

Abstract

Leather (I) is produced by: (A) tanning hide with aldehyde or bisulphate blocked polyisocyanates; (B) optionally tanning the hide with polyaspartic acid or salt, and/or anhydride and/or polyaspartic acid amide; (C) priming the tanned hide with polyurethane and processing aids based on natural products and applying a polyurethane and/or polyester amide finish; and (D) optionally post treating with a leather preserving agent.

Description

The invention relates to biodegradable leather and a process for its Manufacturing.

Tanning converts animal skins into leather by cross-linking the collagen. One The main characteristic of leather is that it is higher than untanned hides Shrinkage temperature, d. H. the improved hot water resistance, and that white appearance (non-transparent) after drying.

The type of tanning that is still dominant today is chrome tanning using chromium (III) compounds under the influence of OH ions cross-linking covalent bonds with the carboxyl groups of collagen be formed. The available with polyfunctional vegetable tannins In contrast, hydrogen bonds to the amide groups of collagen are a lot weaker, which also results in a moderately increased shrinking temperature works. Aliphatic aldehydes, such as. B. glutardialdehyde leading to crosslinking lead over the primary amino groups of collagen as tannins recommended (U.S. Patent 2,941,859).

The use of aliphatic diisocyanates such as hexamethylene diisocyanate (DE-PS 72 981) has not been able to assert itself for toxicological reasons.

The use of bisulfite recommended in U.S. Patents 2,923,594 and 4,413,997 blocked aliphatic, cycloaliphatic or aromatic diisocyanates such as Hexamethylene diisocyanate, isophorone diisocyanate and tolylene diisocyanate as tanning agents fabrics give light, in the case of aliphatic isocyanates even lightfast leathers, however, the tanning liquors are not pH stable.

The automotive industry is increasingly requesting leather that is free on the one hand of heavy metals and on the other hand can be easily disposed of, for example by composting. Because leather according to a definition by Stather and Pauligk "Haut is no longer rotting "(total dep. of the German Leather Institute Freiburg 17th  (1962), p. 37), a conflict of goals seems preprogrammed here: compostable leather does not correspond to the definition mentioned, and one would have to assume that such "Leather" would also lack some of the properties that make it suitable for everyday use do. This means that tanning u. a. also as a preservation method too understand is.

According to the guidelines of the German Waste Working Group (LAGA 10) ge leather (conventionally produced) belongs to the fabrics that are not in compo bull farms may be disposed of because they are not biodegradable and due to their heavy metal content a danger to the humus and to the ground represent water.

The search for biodegradable tannins of natural origin is in the Gange (see e.g. H. Oertel, G. Reich, L. Meyer, E. Lange "Vegetable tanning agents made to measure - a contribution to securing the raw material basis of the leather industry ", Das Leder 1994, pp. 188 to 198). However, tannins are also of natural origin not eo ipso biodegradable, because they are protected by the plant from attack by microbes and fungi and before being eaten, see. J.B. Harborne, Ökologische Biochemie, Heidelberg 1995, p. 170.

The fulfillment of the demands made on biodegradable leather appeared hardly possible:

On the one hand, the customer naturally also expects biodegradable products Leather full usability, on the other hand raises the preservation of such Leather problems on leather is a hydrophilic material with a very large inner Surface and therefore forms an ideal breeding ground for bacteria and fungi. Microbes often release material-damaging enzymes as they grow. Also for reasons of hygiene are microbes and fungi growing in the leather undesirable.

Tanning has a. with the result that a biological breakdown of protein is prevented. So far, biodegrading tanned goods seemed to be a contradiction in terms be.  

From DE-OS 44 22 246 it is known that leather with thermophilic micro can biodegrade organisms in the presence of oxygen. Inorganic In Ingredients accumulate as Chromium III oxide or Chromium III salt and can be one Recovery can be fed. This procedure represents a crucial one Step towards biodegradability of leather. However, it is often poor fillable requirements with regard to the usable microorganisms and the inorganic ingredients.

Surprisingly, it has now been found that without chromium, Titanium, iron, aluminum and zircon tannins to biodegradable, however nonetheless usable leathers arrive when you use a reactive organic tannin pre-tanned or tanned and then for the subsequent processes largely or completely biodegradable products used.

The invention thus relates to a process for the production of leather, according to which

I. nakedness with

• a) aldehydes or
• b) bisulfite-blocked polyisocyanates (pre) tanned,

II. Optionally with the product obtained

• a) polyaspartic acid, its salts and / or its anhydrides and / or
• b) polyaspartic acid amides (after) tanned,

III. a) priming the product obtained with polyurethane and auxiliaries based on natural materials,

• b) applying a finish made of polyurethane and / or polyester amide and

IV. The leather thus prepared, optionally with a leather preservative aftertreated.  

Products are preferred as tanning agents and auxiliaries in the context of the invention selected according to DIN 54 900, part 3 (draft) to at least 30, preferably at least 50 and in particular at least 60% by weight are biodegradable. Preferential at least 60% by weight of the total of all tanning agents and Aid biodegradable.

Preferred aldehydes Ia) include formaldehyde, acrolein, crotonaldehyde, glyoxal, Glutardialdehyde and aldehydes available through the oxidation of fats - i.e. verbin mixtures and mixtures such as those found in F. Stather, "Gerbereichemie and Gerfertechnologie ", Akademie Verlag Berlin 1967, p. 477 ff.

Preferred "bisulfite-blocked polyisocyanates" Ib) are the reaction products

• A. organic polyisocyanate,
• B. based on isocyanate equivalent of A, 0 to 0.4 equivalents of polyether alcohol with built-in polyalkylene oxide units (which refer to equivalents refer to the hydroxyl groups of the polyether alcohol), the polyalkylene oxide units of 40 to 100, preferably 50 to 100 mol% of polyethylene oxide units with a sequence length of 5 to 70, preferably 6 to 60, in particular 7 to 40 in particular,
• C. optionally other NCO-reactive components, and
• D. ammonium or alkali bisulfites or disulfites.

The above reaction products Ib) can be derived from those from A, B and, if appropriate C available intermediates with NCO contents of 3 to 50, preferably 5 up to 45, in particular 20 to 45% by weight (based on the intermediate) subsequent blocking of the free isocyanate groups obtained. The products Ib) then contain - calculated as sodium salt and based on solids - 9.7 to 78 preferably 14 to 74, in particular 46.5 to 74 wt .-% carbamoylsulfonate groups.  

The organic polyisocyanates A) are aliphatic, cycloaliphatic, arali phatic, aromatic or heterocyclic polyisocyanates into consideration, such as z. B. by W. Siefken in Liebigs Annalen der Chemie 562 pages 75 to 136 will.

Preferred polyisocyanates A) are compounds of the formula Q (NCO) _n with an average molecular weight below 800, where n is a number of at least 2, preferably from 2 to 4, Q is an aliphatic C ₄ -C ₁₂ -hydrocarbon radical, a cycloaliphatic C ₆ - C ₁₅ hydrocarbon radical, an araliphatic C ₇ -C ₁₅ hydrocarbon radical or a heterocyclic C ₂ -C ₁₂ radical with 1 to 3 hetero atoms from the series of oxygen, sulfur and nitrogen, for example (i) diisocyanates such as ethylene diisocyanate, 1.4 -Tetramethylene diisocyanate, 1,6-hexa methylene diisocyanate, 1, 12-dodecane diisocyanate, cyclobutane-1,3-diisocyanate, cyclohexane-1,3- and -1,4-diisocyanate and any mixtures of these isomers, 1-iso-cyanato-2 -Isocyanatomethyl-cyclopentane, 1-isocyanato-3,3,5-trimethyl-5-isocyanato methyl-cyclohexane, 2,4- and 2,6-hexahydrotoluenediisocyanate and any mixtures of these isomers, hexahydro-1,3- and / or -1,4-phenylene diisocyanate, per hydro-2,4'- and / or -4,4-dip henylmethyl diisocyanate, 1,3- and 1,4-phenylene diiso cyanate, 2,4- and 2,6-tolylene diisocyanate as well as any mixtures of these isomers, diphenylmethane-2,4'- and / or -4,4'- diisocyanate, naphthalene-1,5-diisocyanate, uret dione-containing polyisocyanates such. B. the bis (6-isocyanatohexyl) uret dione or the uretdior structure-containing dimers of 1-isocyanato-3,3,5-tri methyl-5-isocyanatomethylcyclohexane and any mixtures of the aforementioned polyisocyanates; (ii) trifunctional and higher-functional polyisocyanates such as the isomers of the triisocyanatotriphenylmethane series (such as triphenylmethane-4,4 ', 4''- triisocyanate) and their mixtures; (iii) compounds prepared by allophanatization, trimerization or biuretization from the polyisocyanates (i) and / or (ii) which have at least 3 isocyanate groups per molecule. Examples of polyisocyanates produced by trimerization are the trimerizate of 1-isocyanato 3,3,5-trimethyl-5-isocyanatomethylcyclohexane which is obtainable by isocyanate formation and the polyisocyanates containing isocyanurate groups which are obtained by trimerizing hexamethylene diisocyanate, optionally in a mixture with 2,4-diisocyanate cyanatotoluene . Examples of polyisocyanates produced by biuretization are tris (isocyanatohexyl) biuret and its mixtures with its higher homologs, as described for. B. accessible according to DE-OS 23 08 015.

Particularly preferred polyisocyanates A are those with a molecular weight of 140 to 400 with NCO groups bound to aliphatics or cycloaliphatics, such as. B. 1,4-diisocyanatobutane, 1,6-diisocyanatohexane, 1,5-diisocyanato-2,2-dimethyl pentane, 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane, 1 , 3- and 1,4-diiso cyanatohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane, 1-iso cyanato-1-methyl-4-isocyanatomethyl-cyclohexane and 4,4'-dilsocyanatodicyclohexyl methane, and any mixtures of such diisocyanates. Also araliphatic polyiso cyanates such as the xylylene diisocyanates of the formulas

can be used.

The above diisocyanates are preferably used. But you can also mono-radio tional aliphatic isocyanates such as butyl isocyanate, hexyl isocyanate, Cyclohexyl isocyanate, stearyl isocyanate or dodecyl isocyanate and / or polyiso Use cyanates with an average functionality of 2.2 to 4.2.

The higher-functionality polyisocyanates are preferably essentially from trimeric 1,6-diisocyanatohexane or 1-isocyanato-3,3,5-trimethyl-5- isocyanatomethyl-cyclohexane and optionally dimeric 1,6-diisocyanatohexane or 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane and the corresponding chend higher homologues existing isocyanurate groups and optionally Polyisocyanate mixtures containing uretdione groups with an NCO content of  19 to 24 wt .-%, as by known catalytic trimerization and with isocyanurate formation of 1,6-diisocyanatohexane or 1-isocyanato-3,3,5-tri methyl-5-isocyanatomethyl-cyclohexane can be obtained, and preferably one Have (average) NCO functionality from 3.2 to 4.2.

Other suitable polyisocyanates A are modified by aliphatic or Polyisocyanates prepared with cycloaliphatic diisocyanates with uretdione and / or Isocyanurate, urethane and / or allophanate, biuret or oxadiazine structure as they for example in DE-OS 16 70 666, 3 700 209 and 3 900 053 and in the EP 336 205 and 339 396 are described by way of example. Suitable polyisocyanates are e.g. B. also the ester group-containing polyisocyanates, such as. B. the implementation of Pentaerythritol or trimethylolpropane silyl ethers with isocyanatocaproic acid chloride accessible tetrakis or triisocyanates (cf. DE-OS 37 43 782). Besides, it is also possible to use triisocyanates such. B. Tris-isocyanatodicyclohexylmethane ver turn.

The use of monofunctional and preferably more than di In both cases, functional isocyanates are preferably used in amounts of each limited to a maximum of 10 mol%, based on all polyisocyanates A.

However, the abovementioned aliphatic, cycloali are very particularly preferred phatic and araliphatic diisocyanates.

The polyether alcohols B are accessible in a manner known per se by alkoxylation of suitable starter molecules. Any mono- or polyhydric alcohols with a molecular weight of 32 to 250 can be used as starter molecules to produce the polyether alcohols. Mono-functional aliphatic C ₁ -C ₁₈ , preferably C ₁ -C ₄ alcohols are preferably used as starter molecules. It is particularly preferred to use methanol, butanol, ethylene glycol monomethyl ether or ethylene glycol monobutyl ether as the starter.

Alkylene oxides suitable for the alkoxylation reaction are, in particular, ethylene oxide and propylene oxide, in any order in the alkoxylation reaction  can be used. Any other epoxides such as Butylene oxide, dodecene oxide or styrene oxide can also be used. Pure Polyethylene oxide alcohols are particularly preferred.

Polyalkylene oxide alcohols containing ester groups can also be used. Suitable polyalkylene oxide alcohols containing ester groups are OH-terminated polyester ethers which are obtained by reacting aliphatic C ₂ -C ₈ -dicarboxylic acids or their esters or acid chlorides with polyethers from the group consisting of polyethylene oxides, polypropylene oxides, their mixtures or mixed polyethers, with each OH equivalent of the polyether 0.8 to 0.99 equivalents of carboxyl groups or their derivatives are used, are available and have an average molecular weight below 10,000, preferably below 3,000.

The NCO-reactive components C which may be used include übli mono to tetrafunctional building blocks used in polyurethane chemistry such as Alcohols, amines, amino alcohols and mercaptans with molecular weights below 6,000, preferably less than 2,000, such as. B. polyesters, polyether esters and polycarbonates, unless they fall under definition B.

Preferred components C are "greasing" or "re-greasing" long-chain, optionally branched so-called fatty alcohols or fatty amines with 12 to 30 Carbon atoms and OH groups containing esters of natural fatty acids such as Stearic acid, oleic acid, palmitic acid, linoleic acid, linolenic acid etc.

Very particularly preferred components C are natural OH groups Fats and oils such as castor oil.

The reaction products Ib) from components A to D can be up to Contain 20% by weight of residues of component C.

Preferred blocking agents D are preferably the sodium salts of sulphurous or disulphurous acid, ie sodium bisulfite (NaHSO ₃ ) or sodium disulphide (Na ₂ S ₂ O ₅ ).

The other alkali and ammonium salts can also be used advantageously these acids, namely potassium bisulfite, potassium disulfite, lithium bisulfite, lithium disulfite, Ammonium bisulfite, ammonium disulfite and simple tetraalkylammonium salts these acids such as tetramethylammonium bisulfite, tetraethyl ammonium bisulfite etc. For blocking, the salts are preferred as an aqueous solution solutions with solids contents of 5 to 40 wt .-% used.

The reaction products Ib) can be prepared, for example, as follows:

In a first step, polyisocyanate A is mixed with polyether alcohol B. sets until all OH groups are urethanized. The NCO end thus obtained Permanent prepolymer is then in a second step with alkali or ammonium bisulfite or disulfite blocked until all NCO groups have been converted.

The entire process is particularly preferably carried out solvent-free as a one-pot process. The first step of the reaction is carried out in the temperature range up to 130 ° C., preferably in the range between 50 ° C. and 120 ° C., particularly preferably between 80 ° C. and 110 ° C. The reaction can be followed by titration of the NCO content or by measuring the IR spectra and evaluating the carbonyl band at approx. 2 100 cm ^-1 and is complete when the isocyanate content is not more than 0.1% by weight above the Value that should be achieved with complete sales. As a rule, response times of less than 4 hours are sufficient.

By using catalysts such as dibutyltin dilaurate, tin (II) - octoate or 1,4-diazabicyclo [2,2,2] octane in amounts of 10 to 1,000 ppm on the reaction components, the reaction can be accelerated. The so he NCO prepolymers with NCO contents of 5 to 45 wt .-% are now in a second step at 0 to 60 ° C, preferably at 10 to 40 ° C, with aqueous solutions Alkali or ammonium sulfites and water reacted until all NCO groups have reacted. For this purpose, reaction times of 1 to 12 are generally preferred 3 to 8 hours necessary. The end products are optically clear aqueous solutions, in  In a few individual cases, stable, fine-particle emulsions with medium particles knives under 8000 nanometers. It may be advantageous to add the NCO prepolymers next with 20 to 50 wt .-% aqueous solutions of alkali or ammonium bisulfites or disulfites and after 5 to 45 minutes the remaining water add, so that then a solids content of the aqueous preparations of 10 to 50 wt .-%, preferably 25 to 40 wt .-% results.

To achieve the tanning effect it must be basified, i. H. the pH should be at least 7.5 to preferably a maximum of 9.5. Under these conditions the blocked isocyanate groups react with crosslinking of the collagen (at simultaneous splitting off of the bisulfite group).

To base the reaction products Ib) are all known in the tannery suitable for common denaturing agents:

Sodium carbonate and hydrogen carbonate, magnesium oxide, dolomite, tertiary amines etc. The controlled addition of sodium or potassium hydroxide is also general possible (but uncommon). Magnesium oxide is particularly preferred.

When tanning with the reaction products Ib) one does not need a low one pH value, as is common in mineral tanning, for example. So you can save yourself the salt additive (pimples). Nakedness is e.g. B. up to a pH of 5 descaled to 8 (preferably by 7), the reaction product Ib) added and after one hour running with the basification. (In the case of annealed Magnesium oxide can be started immediately). Depending on the mechanical The flexing effect and thickness as well as disintegration (e.g. enzymatically) of the nakedness can Tanning and preferably the simultaneous basification in 4 to 6 Hours to be completed. In general, however - as with the chrome Tanning is common - after 1 hour's advance and after adding the basifier in a further 2 steps (each after 1 hour running time) overnight run, rinse the next morning and keep working as usual.

Amounts of 1 to 20, preferably 3 to 15, are generally used % By weight Reaction product Ib), based on the pelt weight. The serve with the  Implementation product tanned leather with shrinking temperatures of over 70 ° C, preferably above 75 ° C, as a preliminary stage (analogue wet blue) for retanning.

Bisulfite-blocked polyisocyanates Ib) of the type described are known from DE-OS 44 22 569 known.

The use of the described bisulfite containing polyethylene oxide groups blocked polyisocyanates have application advantages which consist in that residual tanning liquors are obtained which are free of heavy metal ions. With The shrinkage temperatures of the leather that can be achieved with these products are above 70 ° C, mostly over 80 ° C, and therefore within the range for most types of leather required shrinkage temperature range.

The term "polyaspartic acid" IIa) hereinafter excludes its salts, preferably their ammonium, potassium and sodium salts, and their anhydrides such as polysuccin imide, and copolymers obtained by partial dehydration, which in addition to the Succinimide units also contain aspartic acid units. Polysuccinimide can form polyaspartic acid during use by hydrolysis.

The production of polyaspartic acid and its derivatives has long been a subject numerous publications. So the production by thermal polycon aspartic acid (J. Org. Chem. 26 1084 (1961)); see. also DE-OS 22 53 190, U.S. Patents 4,696,981, 5,296,578 and 5,288,783.

US Pat. No. 4,839,461 (= EP-A 256 366) describes the production of polyaspara gic acid from maleic anhydride, water and ammonia. After that, maleic acid anhydride in aqueous medium with the addition of concentrated ammonia solution in converted the monoammonium salt. This maleic acid monoammonium salt can preferably at 150 to 180 ° C in a reactor with a residence time of 5 to 300 Minutes of thermal, optionally continuous polymerization subjected and the polysuccinimide obtained by hydrolysis to polyaspartic acid or a salt thereof.  

In a preferred embodiment, the polyaspartic acid IIa) contains essentially recurring units of the following structure;

and

In general, the proportion of the β-form is more than 50%, in particular more than 70%, based on the sum of a + b.

In addition to the repeating aspartic acid units a) and b), further repeating units can be included, e.g. B.
c) Malic acid units of the formula

d) Maleic acid units of the formula

e) Fumaric acid units of the formula

The "further" recurring units can be present in amounts up to 100% by weight, based on the sum a + b, contained in the polyaspartic acid.

Preferred polyaspartic acids IIa) have as weight average by gel permeate tion chromatography (calibrated with polystyrene) determined molecular weights of 500 to 10,000, preferably 1,000 to 5,000, in particular 2,000 to 4,000.

The polyaspartic acid IIa) can be used in amounts of 0.1 to 20, preferably 0.5 to 12, in particular 1 to 8% by weight (based on the pelt weight in the case of tanning) Fold weight in the case of retanning).

When tanning and retanning, polyaspartic acid can be used in combination with other tanning agents, preferably in a weight ratio of 1: 9 to 9: 1 will. Examples of other tanning agents are vegetable tanning agents and synthetic ones organic tanning agents (so-called "Syntane") including resin tanning agents. Examples such other tannins are described in the following literature: F. Schade and H. Träbel, "Recent Developments in the Field of Synthetic Orga African tanning agents ", Das Leder 33 (1982), 142-154; H. Traubel and K.-H. Rogge, "Retannage and Retanning Materials", JALCA 83: 193-205 (1988); K. Faber, "Tanning agents, tanning and retanning", Vol. 3 in H. Herfeld, Leather Library, Frankfurt 1984; EP-A 118 023, 372746, DE-OS 39 31 039.

The polyaspartic acid is usually used immediately before coloring.

The use of polyaspartic acid will be explained below:  

Folded pre-tanned leather ("wet blue") is in a barrel after a short wash neutralized, thereby reaching a pH range of 4.5 to 5. Then you leave them Neutralization liquor, gives 100% by weight (based on the shaved weight of the leather) Water from 30 to 50 ° C and adds 2 to 5 wt .-% polyaspartic acid or her Derivative, run 2 hours and color.

Polyaspartic acid and its use as a tanning agent are from DE-OS 44 39 990 known.

Preferred polyaspartic acid amides IIb) are products with a number average molecular weight of 700 to 30,000, preferably 1,300 to 16,000, obtainable by reacting

• A. Polysuccinimide with a number average molecular weight of 500 to 10,000, preferably 500 to 6,000, in particular 1,000 to 4,000, with
• B. 5 to 90, preferably 20 to 80 mol%, based on succinimide units of Polysuccinimids A, primary and / or secondary amine, its nitrogen contain substituents 1 to 60, preferably 1 to 36 carbon atoms, by fluorine atoms, hydroxyl, amino groups and / or silicon-organic Residues substituted and / or by oxygen atoms, ester, amide, urea, Urethane groups can be interrupted, at least 2.5, preferably wise at least 15, especially at least 30 mol% of the nitrogen Substitutes of the amine contain at least 12 carbon atoms otherwise
• C. (i) derivatives of C ₁ -C ₁₈ monocarboxylic acids and / or C ₂ -C ₁₀ dicarboxylic acids and / or (ii) monoisocyanates, diisocyanates or epichlorohydrin (for the reaction of amino and / or hydroxyl groups on the nitrogen substituents of the implementation product from A and B), and (mandatory)
• D. 95 to 10, preferably 80 to 20 mol% of ring-opening base in the presence of Water.

That as a starting product for the polyasparagin to be used according to the invention Acid amide IIb) serving polysuccinimide A is known. So the manufacture can Aspartic acid take place with elimination of water, cf. e.g. B. J. Org. Chem. 26 (1961) 1084; FR 70 24 831; P. Neri in J. Med. Chem. 16 (1973), 893; U.S. Patent 4,363,797.

Other processes start from maleic acid or its anhydride and ammonia (DE-OS 43 05 368; US Pat. No. 4,839,461). For example, polysuccinimide Reaction of 80 to 100 mol% maleic acid and 20 to 0 mol% amber acid anhydride (as chain terminator) with ammonia with removal of the reaction water at elevated temperature, generally from 85 to 240, preferably 120 up to 180 ° C.

US Pat. No. 4,839,461 (= EP-A 256 366) describes the production from Malein acid anhydride, water and ammonia. Then maleic anhydride in aq in the medium with the addition of concentrated ammonia solution in the mono ammonium salt converted. This maleic acid monoammonium salt can be preferred example, at 150 to 180 ° C in a reactor with a residence time of 5 to 300 minutes a thermal, optionally continuous polycondensation to poly succinimide.

The starting polysuccinimide A can also be obtained from De hydration of polyaspartic acid or by thermal polycondensation of Make aspartic acid.

The dehydration of aspartic acid or polyaspartic acid to polysuccinimide can at elevated temperature, preferably at 100 to 240 ° C, optionally in Presence of a catalyst e.g. B. in the presence of 0.01 to 1 wt .-%, based on polyaspartic acid, an acidic catalyst such as sulfuric acid, phosphoric acid, Methanesulfonic acid.

Preferred amines B include secondary and - preferably - primary amines, such as. B. monofunctional polyetheramines with a primary or secondary amino group such as α-methyl-ω-amino-polyoxyethylene, α-methyl-ω-aminopropyl-triethoxy silane, aminopropyl-trimethoxy-silane, ammopropyl-heptamethyl-trisiloxane, N-2-aminoethyl -ahnnopropyl-dimethyl-ethoxysilane, N-2-aminoethyl-aminopropyl methyl-dimethoxysilane, perfluorohexyl-ethylamine, N-aminoethyl-N-methyl-perfluorooctylsulfonamide, N, N-dimethylethylenediamine, methylamine, diethylamine, butylamine, stearylamine , Tallow fatty amine, oleylamine, undecylamine, dodecylamine, octylamine, hexyl arine, eicosanylamine, hexadecylamine, 2-ethylhexylamine, morpholine, ethanolamine, diethanolamine, bis-2-hydroxy-propylamine, bis-3-hydroxy-propylamine, 2- or 3 - hydroxypropylamine, ethoxy-ethylamine, ethoxy-ethoxy-ethylamine, butoxy-ethoxy ethoxy-ethylamine, 2-methoxy-ethyl-amine, tetrahydrofurfurylamine, 5-ammopentanol, benzylamine, 4-aminocyclohexylamine, taurine Na salt, glycomethyl methyl ester, N- Methyl aminoethyl sulfonic acid Na salt, dehydroabietylamine, stearyloxypr opylamine,

or their mixtures.

The reaction of polysuccinimide with amines is known in principle; see. e.g. B. DE-OS 22 53 190, EP-A 274 127, 406 623 and 519 119, US-PS 3 846 380, 3,927,204 and 4,363,797; P. Neri et al., Macromol. Syntheses 8, 25. The implementation can be carried out in excess amine B, but is preferably in organic solvents carried out which are inert under the reaction conditions. Lactams such as caprolactam, pyrrolidone, N-methylpyrrolidone, N-methylcaprolactam, polyalkylene diols and their mono- and Diether, such as ethylene glycol, diethylene glycol, triethylene glycol, ethylene glycol dimethyl and diethyl ether and diethylene glycol monoethyl ether, and dimethylformamide and Dimethyl sulfoxide. The solvent content is usually based on 30% by weight on the entire reaction mixture.

The reaction mixture can, although not preferred, water or paraffins contain. The reaction is carried out in a temperature range from 20 to 160 ° C leads, the reaction times being between 2 to 72 hours. The product can by removing the solvent by distillation or by precipitating the product isolated in a non-solvent such as acetone, methanol, ethanol, water, isopropanol and then, if desired, dried. It is also possible the reaction mixture without dispersing further cleaning steps in the water phase.

The polyaspartic acid amides IIb) can be prepared from the reaction product from A and B by opening the remaining built-in succinimide rings. As a ring opening bases C come both alkali metal hydroxides, carbonates and hydrogen carbonates, especially sodium and potassium hydroxide and sodium carbonate, as well Ammonia and amines - including amines B - are considered.  

According to a particular embodiment, maleic acid or maleic acid can be used Mix anhydride and aqueous ammonia in a molar ratio of 0.75 to 1.5 and water distill off. If necessary, one of the above organic solvents during be added to the reaction. If the polysuccinimide is the one you want Has reached molecular weight, amine B is metered in and vice versa at 130 to 160 ° C. puts. A reaction time of 3 to 18, preferably from 4 to 8 hours is in the Rule sufficient for the implementation of amine B. If necessary, an organization nical solvent can be added. The polyaspartic acid is formed directly amide IIb), which is built while opening the remaining ones Succinimiderings with ring-opening base D can be easily dispersed in water.

The polyaspartic acid amides to be used according to the invention contain recurring structural units of the formulas in an idealized form

wherein
R ¹ , R ^{2 are} hydrogen or one of the radicals referred to above as nitrogen substituents, with the proviso that at least one of the two radicals is not equal to hydrogen, and
M⁺ represents H⁺ or an alkali ion, an NH ₄ ion or a primary, secondary or tertiary aliphatic ammonium radical, which preferably carries at least one C ₁ -C ₂₂ alkyl or hydroxyalkyl group.

Suitable residues M⁺ are, for example, hydroxyethylammonium, dihydroxyethyl ammonium, trishydroxyethylammonium, triethylammonium, ammonium, butylam monium, benzyltrimethylammonium, morpholinium, stearylammonium, oleyl ammonium.

The structural units I are preferably present in the polymer in an amount of 5 to 90, in particular 20 to 80 mol%, based on all recurring units. Preferred polyaspartic acid amides contain an average of at least one C ₁₂ -C ₂₂ alkyl and / or alkylene radical per structural unit I.

The structural units II in the polymer are preferably in an amount of 95 to 10, in particular 80 to 20 mol%, based on all recurring units hold. Polyaspartic acid amides, the carboxyl groups of which are particularly preferred partially neutralized form. The preferred degree of neutralization is 10 to 70, preferably 20 to 50%. The structure IIC accounts for 0 to 20 mol%, based on structures II.  

The structural units in are in the polymer in an amount of 0 to 5 mol%, based on all recurring units. Preferred polyaspartic acid amides contain less than 1 mol% of structural units III.

In the event that polysuccinimide A has been prepared from polyaspartic acid, the contains the above-mentioned repeating units C), the carboxyls groups of these recurring units must be amidated.

Suitable nitrogen substituents R ¹ , R ² independently of one another include, for example, optionally hydroxyl-substituted C ₁ -C ₂₂ alkyl or C ₂ -C ₂₂ alkenyl groups of hydroxyethyl, hydroxypropyl, methyl, ethyl, butyl, hexyl, octyl, octenyl, decyl , Undecyl, Undecenyl, Dodecyl, Tetradecyl, Hexadecyl, Oleyl, Octadecyl, 12-Hydroxy-octadecenyl, C ₅ -C ₁₀ -Cydoalkyl residues such as cyclohexyl, C ₁₂ -C ₃₀ residues interrupted by oxygen atoms, ester, amide, urethane groups such as Stearoyloxyethyl, stearyloxyethoxyethyl and stearylcarbamoyloxyethyl as well as residues of the formulas

wherein
R ⁵ , R ⁶ C ₁ -C ₃₀ alkyl, C ₂ -C ₃₀ alkenyl, C ₅ -C ₁₀ cydoalkenyl,
R ⁷ to R ^{9 are} C ₁ -C ₄ alkyl or alkoxy and
M⁺ has the meaning given above.

Nitrogen substituents caused by oxygen atoms, ester, amide or urethane groups are interrupted, in principle either by using these Groups of amines B already present or subsequently by reaction initially introduced reactive nitrogen substituents with suitable reactants ent stand.

Amide and ester groups can, for example, by subsequent reaction of already introduced aminoalkyl or hydroxyalkyl radicals by reaction with reactive carboxylic acid derivatives, preferably derivatives of C ₁ -C ₁₈ monocarboxylic acids or C ₂ -C ₁₀ dicarboxylic acids, such as anhydrides or chlorides, e.g. B. Acetane hydride, acetyl chloride, acrylic and methacrylic acid chloride, methacrylic anhydride, succinic anhydride, maleic anhydride, stearic acid chloride, phthalic anhydride, are introduced.

Urethane groups and urea groups can be replaced by, for example Implementation of already introduced amino or hydroxyalkyl radicals with mono- or di isocyanates such as butyl isocyanate, stearyl isocyanate, hexamethylene diisocyanate, Toluy lendiisocyanate, isophorone diisocyanate, 1-isocyanatomethyl-4-methyl-4-cyclohexyliso cyanate are introduced. Monoisocyanates are particularly preferred. Networked Pro products are not preferred.

Nitrogen substituents interrupted by oxygen atoms become the best introduced by using appropriate amino ethers B.  

Epoxy groups can, for example, be added by subsequent epoxidation guided alkenyl groups, e.g. B. with peracids. Another possibility alkylation with epichlorohydrin.

The polyaspartic acid amides IIb) are very often self-dispersing, especially if the proportion of structural units I is less than 50 mol%. But it can also be external Dispersants are used; in principle, cationic, anioni come as such cal and nonionic dispersants in question, such as. B. in "Methods of Organi chemistry "(Houben-Weyl), 4th edition, volume XIV / 1, Georg Thieme Verlag, Stuttgart 1961, p. 190 f. are described.

Preferred dispersants include, for example, C ₈ -C ₁₈ -n-alkyl sulfates, C ₈ -C ₁₈ - n-alkyl-benzenesulfonates, C ₈ -C ₁₈ -n-alkyl-trimethyl-ammonium salts, n-di-C ₈ -C ₁₈ - alkyl-dimethyl-ammonium salts, C ₈ -C ₁₈ -n-alkyl-carboxylates, C ₈ -C ₁₈ -n-alkyl-dimethylamine oxides, C ₈ -C ₁₈ -n-alkyl-dimethylphosphine oxides and - preferably - oligo ethylene glycol mono -C ₆ -C ₁₈ alkyl ethers with an average of 2 to 30 ethoxy groups per molecule. The n-alkyl radicals can also be replaced by partially unsaturated linear aliphatic radicals. Particularly preferred dispersants are oligoethylene glycol mono-C ₁₀ -C ₁₄ alkyl ethers with an average of 4 to 12 ethoxy groups per molecule, in particular oligoethylene glycol mono-C ₁₂ alkyl ethers with an average of 8 ethoxy groups per molecule.

Preferred dispersants further include oleic acid, oleic acid sarcosides, ricinol acid, stearic acid, fatty acid partial esters of polyols such as glycerin, trimethylol propane or pentaerythritol and their acylation, ethoxylation and propoxylie tion products, e.g. B. glycerol monostearate and monooleate, sorbitan monostearate and monooleate, sorbitan tristearate and trioleate and their reaction products with Dicarboxylic anhydrides such as succinic anhydride, maleic anhydride, phthal acid anhydride or tetrahydrophthalic anhydride, reaction products from bis- (hydroxymethyl) tricyclodecane and maleic anhydride or succinic anhydride and their derivatives, preferably in the form of their alkali or ammonium salts.  

Particularly preferred dispersants are salts of long-chain fatty acids preferably oleic acid and an amino alcohol, preferably hydroxyethylamine, bis hydroxyethylamine or trishydroxyethylamine.

The dispersion of polyaspartic acid amides IIb) can be prepared in such a way that the polyaspartic acid amides in an aqueous dispersant solution, preferably dispersed with heating to temperatures of 40 to 95 ° C, with stirring.

In general, it is recommended to use the polyaspartic acid amides IIb) without intermediate insulation directly from the reaction mixture, the organi contains solvent to disperse. So you can for example an aq dispersant solution to the reaction mixture with stirring at temperatures of 70 to 130 ° C, so that a mixing temperature of 70 to 95 ° C, and distill off the organic solvent. The other way around, of course Reaction mixture in aqueous dispersant solution or a mixture of reaction Disperse the mixture and dispersant in water. You can also see the distance do without the solvent; in this case the solvent content of the Dispersion should not exceed 10% by weight.

The dispersant content is generally not more than 30, preferably 3 to 15% by weight, based on the finished dispersion.

The solids content of the dispersions can be 5 to 70% by weight. The middle part The size of the dispersed polyaspartic acid amides is generally from 100 to 1000, preferably 100 to 700 and in particular 100 to 400 nm.

To facilitate the penetration of the aids into the leather, it may be desirable be to reduce the particle size of the disperse phase. He can already do this holding pre-emulsion under high shear rate in known dissolvers, dispersers machines, such as in a jet disperser, or mixers with the rotor-stator principle or high pressure homogenizers are treated. The dispersion time can between a few minutes and up to 4 hours. The dispersion is done before  preferably carried out in a temperature range between 20 and 75 ° C. The Pressure in dispersing machines can be 2 to 2 500 bar.

The dispersions can be used in particular at solids contents above 40% by weight. are in the form of pastes, but can be diluted well with water. The Dispersions with a solids content below 40% by weight are in the form of pourable emulsions or microemulsions. The pH of the emulsions or Pastes are between 4.5 and 12, preferably in the pH range between 4.5 and 10.

The leather treatment can be done with an aqueous liquor containing the polyaspartic acid contains amides IIb).

To do this, the leather is added to the liquor by application using rollers or in one Containers, preferably in a tanning barrel, brought into contact. After treatment the leather is dried.

The individual process steps should be illustrated using the following example:

• 1. Neutralize the tanned leather
• 2. Wash
• 3. Add the liquor containing polyaspartic III
• 4. Reduction of the pH value by adding a carboxylic acid to pH values <4.5, preferably 3.0 to 4.5
• 5. Wash
• 6. Drying.

The above polyaspartic acid amides IIb) and their use as leather auxiliaries are described in DE-OS 195 28 782.  

Preferred polyurethanes IIIa) and IIIb) (hereinafter simplified: "III") are, for example, in EP-A 572 256 and 593 975, in DE-OS 20 35 732 and 26 51 506 and in DE-PS 43 19 439. Particularly preferred poly urethanes III are ureas which have polyurethanes which, according to known processes, maintain an equivalent ratio of isocyanate groups to isocyanate-reactive groups of 1: 1 to 2: 1

• a) a diisocyanate component consisting of
  • a1) hexamethylene diisocyanate or
  • a2) mixtures of hexamethylene diisocyanate with a total of up to 60% by weight, based on the mixture, of 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane and / or 4,4'-diisocyanatodicyclohexyl methane and / or 1 -Methyl-2,4 (6) -diisocyanatocyclohexane with
• b) a diol component consisting of
  • b1) at least one polyester diol of a molecular weight of 500 to 10,000 which can be calculated from the hydroxyl group content from (i) adipic acid and / or succinic acid and (ii) at least one alkane diol with 2 to 6 carbon atoms or
  • b2) a mixture of such polyester diols with up to 32% by weight, based on the total weight of component b), of alkane diols with 2 to 6 carbon atoms which may have ether groups,
• c) a diamine component in an amount of 2 to 50 equivalent%, based on the total amount of the components present in components b) and c), which are reactive towards isocyanate groups, consisting of
  • c1) diamino sulfonates of the general formula
    H ₂ N - (- CH ₂ -) _n -NH - (- CH ₂ -) _m -SO ₃ Me
    or
  • c2) Mixtures of diaminosulfonates c1) with up to 70% by weight, based on the total weight of component c), of ethylenediamine, if appropriate
• d) hydrophilic polyether alcohols of the general formula
  HXOR
  in an amount of up to 10% by weight, based on the total weight of components b), c) and d), and if appropriate
• e) water which is not included in the calculation of the equivalent ratio of Isocyanate groups to groups which are reactive towards isocyanate groups comes in,

are available, wherein in the general formulas mentioned
m and n independently of one another represent numbers from 2 to 6,
Me stands for potassium or sodium,
R stands for a monovalent hydrocarbon radical with 1 to 12 carbon atoms, and
X is a polyalkylene oxide chain in the molecular weight range 88 to 4000, the alkylene oxide units of which consist at least 40% of ethylene oxide units and the rest of propylene oxide units.

The diisocyanate component a) preferably consists exclusively of hexamethy lendiisocyanate.

The diol component b) either consists of b1) at least one polyester diol or b2) from a mixture of at least one polyester diol b1) with up to 32, preferably up to 10% by weight of at least one, optionally ether groups pointing alkanediols having 2 to 6 carbon atoms.

Suitable polyester diols b1) are those from the hydroxyl group content calculable molecular weight 500 to 10,000, preferably 1,000 to 2,500 Basis of (i) adipic acid and / or succinic acid and (ii) optionally ether group-containing alkanediols having 2 to 6 carbon atoms such as. B. ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol and / or 1,6-hexanediol. Polyester diols, only ethylene glycol and / or 1,4- Butanediol have been used as the diol are particularly preferred.

In the case of chain extensions which may have hydroxyl groups agents to be used, optionally containing ether groups alkane diols with 2 to 6 carbon atoms are those of the just exemplary Art.

The diamine component c) either consists of c1) diaminosulfonates above general formula or from c2) mixtures of such diaminosul fonate with ethylenediamine, which, if at all, in amounts of up to 90, preferred up to 70 equivalent%, based on the reaction to isocyanate groups tionable amino groups of component c) is used. Most notably preferred diaminosulfonates are the potassium or sodium salts of N- (2-amino ethyl) -2-aminoethanesulfonic acid.

The diamine component c) is generally present in an amount of 1 to 10 preferably 2 to 5 wt .-%, based on the weight of component b), mitver turns.  

The optional structural component d) is a hydrophilic monohydric polyether alcohol of the general formula

HXOR,

in which
R and X have the meaning already mentioned.

Such polyether alcohols are preferred for which
R represents an aliphatic hydrocarbon test with 1 to 4 carbon atoms and
X represents a polyalkylene oxide chain in the molecular weight range 500 to 4,000, in which at least 40, in particular at least 70 and particularly preferably 100% of the alkylene oxide units, ethylene oxide units and the remaining alkylene oxide units are propylene oxide units.

The production of such monohydric polyether alcohols is done per se known alkoxylation of suitable starter molecules R-OH, such as methanol, n-butanol, n-hexanol or n-dodecanol with the preferred use of ethylene oxide and optionally propylene oxide, ent in the above statements speaking proportions of the alkylene oxides. Here, the above Alkylene oxides are used as a mixture and / or in succession.

The monohydric polyether alcohols d) are, if at all, in amounts of up to 10, preferably up to 3 wt .-%, based on the total weight of the compo ment b), c) and d) used.

As a further structural component that may be considered at the manufacturer position of the urea group-containing polyurethanes III is e) water,  which is particularly to be considered as a reactant if the Production of the polyurethanes the chain extensions to be carried out in the last stage tion reaction of previously prepared NCO prepolymers in an aqueous medium follows, especially when the diamines c) dissolved in the water are obtained in on the NCO groups of the NCO prepolymers, sub-equivalent amounts for one sentence arrive.

In addition to these structural components, there is also a trifunctional connection in principle in minor amounts such as glycerin or Trimethylolpropane, which is either incorporated in small quantities in the polyester b1) or can be used in free form as part of component b2). The The use of such branching molecules usually has to monofunctional connections are balanced so that, purely arithmetically, again linear polymers result.

The production of the urea groups containing polyurethanes III from the at playful construction components can be used according to any method of the state the technology. However, preference is given to the known prepolymer process worked, in such a way that from components b) and optionally d) and the diisocyanate component a) while maintaining a NCO / OH equivalent ratio of 1.5: 1 to 4: 1, preferably 1.8: 1 to 2.5: 1 Manufactures NCO prepolymer or semi-prepolymer and this with the Component c) reacting with chain extension.

The prepolymer or semi-prepolymer is generally solvent-free Temperatures of 20 to 150 ° C prepared and then in a suitable Lö solvent dissolved. Of course, the formation of the prepolymers or semi prepolymers also take place directly in a solvent. As a solvent come especially inert to isocyanate groups, unlimited with water miscible solvents. Acetone is preferred as solvent turns.  

The prepolymers or semi-prepolymers thus produced are in the second Reaction step with component c) with chain extension for reaction brings. Here is the equivalent ratio of isocyanate groups of the prepolymers or semi-prepolymers on the one hand to be reactive towards isocyanate groups Amino groups of component c) on the other hand at 1: 1 to 20: 1, preferably 1.2: 1 to 4: 1. The chain extension reaction can be in solution, preferably in acetone sher solution or in an aqueous medium such that the solution of the prepolymers or semi-prepolymers in organic solvent with a Solution of component c) combined in water with thorough mixing. How As already indicated, chain extension may also take place here reaction by reaction of the NCO groups of the prepolymers or semi-prepoly mer with the water. In the mentioned, preferred 2-stage production of Polyurethanes III containing urea groups become the equivalent ratios between isocyanate groups and reactive towards isocyanate groups Groups of the two reaction stages within the scope of the disclosure made so ge chooses that the total ratio of isocyanate groups to isocyanate groups reactive groups of components b) to d) the above Ratio of 1: 1 to 2: 1. The water never goes into the tank calculation of the above-mentioned equivalent ratios.

The chain extension reaction generally takes place within the temperature range range from 20 to 50 ° C.

In principle possible, but by no means preferred, the chain extension can reaction also in the melt, d. H. in the absence of solvents and Water take place (melt dispersion method).

The polyurethanes III are preferably applied in the form of aqueous dispersions brings.

The term "aqueous dispersion" is also intended to encompass aqueous solutions contained therein may be present when the concentration of hydrophilic centers in the urea Group-containing polyurethanes is sufficiently high to be water-soluble   guarantee. Often these are those to be used according to the invention Dispersions around aqueous systems that contain both dispersed and dissolved urine Containing polyurethane groups.

For the preparation of the aqueous dispersions, the above-mentioned Gear materials a), b), c) and optionally d) and / or optionally e) in the mentioned proportions used.

Such particularly preferred polyurethanes III are from DE-OS 195 17 185 known.

The chain-extended polyurethanes III or their solutions in organic solvents, if the chain extension reaction was carried out in the absence of water with the disperser water mixed, whereupon the distillative removal at least a part of the auxiliary solvent which may be used is connected. if the Chain extension reaction in an aqueous medium can be used to prepare the aqueous dispersions, if necessary, further water can be added. Also in In this case the auxiliary solvent used can of course be desired if removed by distillation.

In general, the total amount of water used is so dimensioned that 25 to 50 wt .-% dispersions, based on the dispersed solid substances on the one hand and the continuous phase on the other.

Preferred polyurethanes III are known for example from DE-OS 44 21 292 be. These are implementation products

• a) at least one glycerol monoester of a saturated C ₁₂ -C ₁₈ monocarboxylic acid,
• b) at least one diisocyanate from the series tolylene diisocyanate, hexamethy lendiisocyanate and IPDI (isophorone diisocyanate) and  
• c) dimethylolpropionic acid (= 2,2-bis (hydroxymethyl) propionic acid),

the amounts of components a) to c) being chosen so that the molver ratio of the isocyanate groups of b) to the sum of the hydroxyl groups of a) and c) 0.5 to 1.05, preferably 0.8 to 1.0 and the molar ratio c / a 0.7 to 1.5, preferably be 0.8 to 1.2 and the carboxyl groups originating from c) at least are partially neutralized.

These polyurethanes III can, for example, be prepared in such a way that the Glycerol ester a) with the diisocyanate b) and the resulting addition compound reacted with the diol c). The carboxyl groups of c) can be neutralized before or after the implementation of c).

Suitable neutralizing agents include, for example, alkali and alkaline earths hydroxides, carbonates and hydrogen carbonates, such as sodium hydroxide, potassium hydroxide, sodium carbonate and hydrogen carbonate, potassium carbonate, magnesium, Calcium and barium hydroxide, as well as ammonia, primary and secondary amines with 1 up to 30, preferably 3 to 18 carbon atoms, such as methylamine, ethylamine, n-propylamine, Isopropylamine, n-butylamine, isobutylamine, hexylamine, cyclohexylamine, methyl cyclohexylaiin, 2-ethylhexylamine, n-octylamine, isotridecylamine, tallow fatty amine, Stearylamine, oleylamine, dimethylamine, diethylamine, di-n-propylamine, diisopropyl amine, di-n-butylamine, diisobutylamine, dihexylamine, dicyclohexylamine, dimethyl cyclohexylamine, di-2-ethylhexylamine, di-n-octylamine, diisotridecylamine, ditallow fat amine, distearylamine, dioleylamine, ethanolamine, diethanolamine, n-propanolamine, Di-n-propanolamine and morpholine.

Preferably at least 50%, in particular at least 80%, of those from c) neutralized carboxyl groups.

The reactions can be carried out in the absence or presence of organic solvents occur. Preferred organic solvents are for the starting used compounds inert and include, for example, acetone, methyl ethyl ketone, tetra  hydrofuran, dichloromethane, chloroform, perchlorethylene, ethyl acetate, dimethyl form amide, dimethyl sulfoxide, N-methylpyrrolidone.

The reaction of the compounds a) and b) can by cobalt naphthenate, zinc octoate, preferably dibutyltin dilaurate or dibutyltin diacetate, and by ter tertiary amines such as triethylamine or 1,4-diaza [2.2.2] bicyclooctane can be catalyzed.

The polyurethanes III can be dispersed in water, for example by the neutralizing agent is added as an aqueous solution and, if appropriate, existing withdrawing the organic solvent. The polyurethanes III are more appropriate as aqueous preparations with an ester urethane content of 1 to 40% by weight in an amount of 0.2 to 10 wt .-%, based on fold weight and polyurethane III firm, used.

The Polyurethane III pulls out of the fleet excellently on the leather and make the leathers hydrophobic and soft as well as grain-proof, without the dyeability to adversely affect.

Preferred auxiliaries based on natural substances IIIa) include casein, albumin, gelatin, Protein breakdown products, starch, flour, chitosan, gum arabic, cellulose and deri dated (e.g. (partially) esterified) cellulose, lignin derivatives, vegetable tannins (if they are either in biodegradable form or in a minor amount, so that they do not hinder the degradation of the leather), vegetable or animal fats (F. Stather, "tanning chemistry and tanning technology", Akademie Verlag Berlin 1967, P. 517 ff;), possibly oxidized fatty substances before, during or after tanning, Plant-based fillers such as carob flour, guar, etc.

Preferred polyesteramides IIIb) are known, for example, from US Pat. Nos. 4,343,931 and 4,529,792 and JP-A 79 119 593 and 79 119 594. Particularly preferred polyester amides IIIb) are polymers which contain aliphatic ester and aliphatic amide structures, the proportion by weight of the ester structures being 30 to 80% and the proportion of the amide structures being 70 to 20%. They preferably have an average molecular weight (M _w determined by gel chromatography in m-cresol against standard polystyrene) of 10,000 to 300,000, preferably 20,000 to 150,000.

The starting products for the production of polyester amides IIIb) can be made from the following groups:

Dialcohols such as ethylene glycol, 1,4-butanediol, 1,3-propanediol, 1,6-hexanediol, diethylene glycol
and or
Dicarboxylic acid such as oxalic acid, succinic acid, adipic acid and others in the form of their respective esters (methyl, ethyl, etc.)
and or
Hydroxycarboxylic acids and lactones such as caprolactone
and or
Amino alcohols such as ethanolamine, propanolamine
and or
cyclic lactams such as ε-caprolactam or laurolactam
and or
ω-aminocarboxylic acids such as aminocaproic acid
and or
Mixtures (1: 1 salts) of dicarboxylic acids such as adipic acid, succinic acid etc. and diamines such as hexamethylene diamine, diaminobutane.

Likewise, both hydroxyl- or acid-terminated polyesters with molecular weight Weights between 200 and 10,000 are used as the ester-forming component.

Preferred polyesteramides IIIb) can contain 0.01 to 5% by weight, preferably 0.1 to 2 wt .-%, based on the sum of all starting components, branching contain. Preferred branching agents include e.g. B. trihydric alcohols such as Glycerin, trimethylolethane and propane, tetravalent alcohols such as pentaerythritol or tripasic carboxylic acids such as citric acid.

Preferred polyesteramides IIIb) contain built-in residues of divalent aliphatic C ₂ -C ₁₂ -, preferably C ₂ -C ₆ alcohols, aliphatic C ₂ -C ₁₂ -, preferably C ₂ -C ₆ dicarboxylic acids, C ₁ -C ₁₂ - , preferably C ₄ -C ₆ - amino carboxylic acids or cyclic lactams with 5-12, preferably 6-11 carbon atoms in the ring.

The polyester amides IIIb) can also be obtained using the 1: 1 aliphatic salt Dicarboxylic acid and aliphatic diamine, e.g. B. the "AH salt" from adipic acid and 1,6-Hexamethylenediamine can be produced.

Preferred polyesteramides IIIb) contain 6-amino as the amino carboxylic acid building block hexanoic acid residues.

Polyesteramides IIIb) from ε-caprolactam, adipic acid and 1,4-butanediol are special preferred.

The polyesteramides IIIb) preferably have an ester content of 35 to 65, in particular special from 35 to 55 wt .-%.

The synthesis of the polyester amides IIIb) can be carried out by polymerizing the starting ver bindings are made at elevated temperature. The water of reaction can during  or - preferably - distilled off after the reaction (given in the latter case if necessary together with excess monomers), if appropriate with min different pressure. The starting compounds are statistically incorporated into the polymer built-in.

The synthesis can be done either by the "polyamide method" by mixing the off gang components, optionally with the addition of water and subsequent Removing water from the reaction mixture, as well as after the "polyester Method "by adding an excess of diol with esterification of the acid groups and subsequent transesterification or transamidation of these esters. In In this second case, in addition to water, the excess of glycol becomes again distilled off.

The polycondensation can be accelerated by using catalysts will. Both the known phosphorus compounds that be the polyamide synthesis accelerate, as well as acidic catalysts and salts such as oxides, acetates of Mg, Zn, Ca etc. for the esterification as well as combinations of the two are used Acceleration of polycondensation possible.

The particularly preferred polyester amides IIIb) z. B. in DE-OS 43 27 024 described.

The leathers produced according to the invention can be based on preservatives Thiocyanatomethylbenzthiazole or pyrocarbonates, e.g. B. Pyrocoals acid ethyl ester, are treated. The pyrocarbonic acid esters of Advantage because they are in the presence of water in the ecologically harmless compo Carbon dioxide and ethanol decompose and later composting does not hinder more.

Another object of the invention are leather, the ge at least 30 wt .-% according to DIN 54 900, part 3 (draft), are biodegradable and a shrinking temperature tur, measured according to DIN 53 336, of at least 65 ° C, preferably at least 70 ° C, in particular at least 80 ° C, have.  

Molecular weights of polymeric compounds for the purposes of this invention are as Number average molecular weights (unless otherwise stated).

The percentages in the following examples relate to the Weight.  

Examples Resources used

BAYCHROM CP:
Chromium tanning agent from Bayer AG of medium reactivity for the BAYCHROM C process with 7.2% chromium oxide
BAYGENAL Gray S GL:
Acid Black 220 from Bayer AG
BAYGENAL Braun S RL:
Acid Brown 413 from Bayer AG
BAYMOL FD fl .:
80% aqueous solution of a nonionic emulsifier from Bayer AG
BAYMOL TO:
33% aqueous solution of nonionic emulsifiers from Bayer AG
CHROMOSAL B:
33% basic chrome tanning agent with 25% chromium oxide from Bayer AG
CHROMOSAL BF:
42% basic, weakly masked chrome tanning agent from Bayer AG with 25% chromium oxide
ENSUL AM 90:
approx. 92%, sulfited, natural oil from Zschimmer and Schwarz, D-56112 Lahnstein
EUKANOL Black D:
aqueous soot preparation from Bayer AG formed with the help of casein
EUREKA 800 FR:
Mixture of natural and synthetic oils from Atlas Oil, Newark NJ (USA)
Magnesium oxide:
Magnesia 322 from Magnesia GmbH, Lüneburg
BAYGENAL Braun CGG:
Acid Brown 83 from Bayer AG
PRINOL F41:
Lubricant based on polymer and synthetic products from Zschirmer & Schwarz
LEVADERM medium brown:
Chromium complex dye in ethoxypropanol from Bayer AG
LEVADERM brown:
Chromium complex dye in ethoxypropanol from Bayer AG
LEVADERM black-brown:
Chromium complex dye in ethoxypropanol from Bayer AG
BAYDERM Finish DLF:
40% polyurethane dispersion from Bayer AG
DEGRANIL DLN W 50:
50% polyurethane dispersion from Bayer AG
EUDERM matting SN:
Matting agent slurry in aqueous preparation from Bayer AG
BAYDERM additive VL:
Viscosity regulator based on PU from Bayer AG
EUDERM Fluid G:
Leveling agent on aqueous, organic basis from Bayer AG
Quebracho, Mimosa, Chestnut:
commercially available vegetable tanning agents
POLYZIM 202:
proteolytic pickling agent based on penkreas from Diamalt, D-83064 Raubling
PREVENTOL WB:
biodegradable preservative from Bayer AG
TANIGAN 3 LN:
lightfast, synthetic exchange and white tanning agent from Bayer AG
TANIGAN TF 2N:
organic, synthetic tanning agent from Bayer AG
TANIGAN OS:
organic, synthetic tanning agent from Bayer AG

Blocked polyisocyanate 1

168 g (1.00 mol) of hexamethylene diisocyanate are mixed with 25 g at room temperature (0.05 mol) polyether 2 (see below) and heated to 100 ° C. The tempera is held for 2 hours and then the NCO content is determined (calculated 42.4%, found 41.9%). After cooling to 15 ° C., 509 g (1.91 mol) 39% aqueous sodium bisulfite solution added and 30 minutes after stirring, the temperature rising to about 45 ° C. Now it is desalinated with 276 ml Water the solids content adjusted to 40%. After stirring at room for 7 hours temperature, you get a water-clear solution with a pH of 5.8.

Polyether 2

Ethylene oxide polyether of molecular weight 500 started on methanol with an ethylene oxide group content of 93.6%.  

Ester urethane 3

A heatable, 500 ml three-necked round bottom flask serves as apparatus Stirrer, reflux condenser with drying tube and dropping funnel is provided.

17.9 g of glycerol monostearate (0.05 mol) are placed in the flask. Successively 45 mg of dibutyltin diacetate, 50 ml of anhydrous acetone and 14.72 ml (17.9 g) are added Toluene diisocyanate-2.4 / -2.6 (ratio 80/20) (0.1028 mol). Now it is 30 minutes heated to boiling for a long time. Then 11.75 g of the triethylamine salt are left of 2,2-bis (hydroxymethyl) propionic acid (0.05 mol), dissolved in 50 ml of anhydrous Acetone, dropwise within 10 minutes. After an hour of reaction time under The reflux stops the formation of the ester urethane. The solution is clear, moderately viscous and colored slightly yellow. For dispersing are now while maintaining a weak reflux of the acetone, 250 ml of deionized water were added dropwise. To Removal of the acetone by vacuum distillation results in an approximately 17% clear solution of the ester urethane.

Tanning agent 4

100 g of polysuccinimide with an average molecular weight M _w of 3000 are reacted in 100 g of N-methylpyrrolidone with 69.5 g of stearylamine (0.25 mol / mol imide) at 140 ° C. The mixture is stirred at this temperature for 8 hours. Then it is cooled to room temperature. The reaction mixture is poured into excess (1500 ml) of methanol, the reaction product precipitating in fine particles. The product is suction filtered through a suction filter and washed with methanol and dried. A light powder is obtained.

100 g of the product obtained are placed in a solution heated to 80 ° C. which consists of 10 g oleic acid, 4.3 g monoethanolamine and 342.9 g water. The Dis persion is homogenized at 80 ° C for 60 minutes. The particle size is less than 500 nm. The dispersion is adjusted to a solids content of 25% by weight.  

Polyurethane dispersion 5

83.4 g of a polyester of adipic acid, ethanediol and 1,4-butanediol in the weight ratio of ethanediol: butanedio = 1.4: 1 of the molecular weight M _n 2000 and 3 g of a monohydric polyether alcohol of the molecular weight M _n 2240, prepared by alkoxylation of n -Butanol using a mixture of propylene oxide and ethylene oxide in the molar ratio PO: EO = 1: 7.1 are degassed together at 120 ° C. and vacuum for 30 minutes. Under nitrogen, 0.1 g of benzoyl chloride and 13.7 g of hexamethylene diisocyanate are added to the batch in one pour. After stirring for 1 hour at 120 ° C., the NCO content is 2.84%. The prepolymer is dissolved in 300 g of acetone at 50 ° C. and a mixture of 4.8 g of a 50% strength aqueous solution of the sodium salt of N- (2-aminoethyl) -2-aminoethanesulfonic acid (AAS salt) and 1, at room temperature. 15 g of ethylenediamine and 20 g of water were added. After 15 minutes, 230 g of water are added and the acetone is removed at 60 ° C. and 140 mbar. The distillation residue left is 337 g of a thin, white dispersion with 30% polyurethane.

example 1

Ashes nakedness are split to 2.2 mm. Then the nakedness turns into a usual one Given the tanning barrel and once with 200% (percentages refer here and in following gap weight) water at 30 ° C for 10 minutes. Then lets the fleet. In the subsequent descaling, 30% water at 30 ° C, 2% ammonium sulfate and 0.2% sodium meta bisulfite were added and 10 minutes emotional. Then add 0.2% formic acid (diluted 1:10) and 0.2% BAYMOL FD liquid and let run for 20 minutes. With 0.5% Polyzim 202 Stained for 30 minutes in the same fleet. The result is a pH of 8.4. (Cut the nakedness with phenolphthalein colorless.) Then let the liquor drain.

You wash 2 times with 150% water (from room temperature) and the liquor is drained.  

A quantity of leather is removed which is processed further in accordance with Example 1.1. 30% water at 30 ° C is filled in and 0.35% Magnesium oxide (Magnesia 322) and after 60 minutes 75% of the blocked poly Isocyanate 1 added. After a running time of 5 hours, a pH value is established from 7.1 a; another 0.35% magnesium oxide (Magnesia 322) is added and the mixture is left run overnight (final pH 9.4); the next morning has emerged Leather a shrinking temperature of 78 ° C.

The liquor is drained, the leather is at 10 minutes. Room temperature ge rinsed, then they are wilted and folded to a thickness of 1.0 mm.

The folded leather is placed in a barrel and washed for 10 minutes with 200% water at 30 ° C (% data relate to fold weight). The liquor is let off.

In a new fleet of 100% water, 40 ° C, 0.5% formic acid (with water diluted 1: 4). After 60 minutes, a pH of 4.8 is established.

8.3% of the tannin 4 are then added to this liquor and the mixture is left to run for 30 minutes. Then add 2% ENSUL AM 90 and let it run for another 60 minutes then add 4% of the ester urethane 3. After 30 minutes you give a mixture of 3% TANIGAN 3 LN and 3% sweetened chestnut and leaves this Run for 40 minutes.

This is followed by a 40-minute pre-coloring with a mixture of 4% BAYGENAL gray S-GL and 0.4% BAYGENAL brown S-RL and a pre-greasing in 30 minutes with 4% EUREKA 800 FR (diluted 1: 4 with water). Then you increase the liquor by 100% with 50 ° C hot water, the 5 minutes run to add 2% formic acid (diluted 1: 4 with water) give. After a running time of 15 minutes, a pH of 4.9 is established.

The fleet was drained into it. In a fresh liquor of 100% water, 50 ° C with 8% EUREKA 800 FR (diluted 1: 4 with water) in 30 minutes regreased. The fleet is drained. In a new fleet of 200% water, 50 ° C,  was then treated with 2% BAYGENAL S-GL and 0.2% BAYGENAL Braun S-RL in Overstained for 30 minutes. Subsequently, by adding 1% formic acid (with Water diluted 1: 4) in 20 minutes a final pH of 3.1 posed. The liquor was drained and heated at 25 ° C. in the overflow for 5 minutes Rinsed water.

The leathers were stored on the trestle overnight, then stretched wet, air-dried, air-conditioned, stollen, grilled, stretched again and partly pulled judges.

Example 1.1 (comparison)

Part of the ashes, descaled and decalcified in Example 1 were as follows tanned with mineral tannin. For this, the nakedness in 20% water, 20 ° C, with 4% table salt (information based on the weight of the skin) 5 minutes, with 0.5% PREVENTOL WB (diluted with water in a ratio of 1: 2) for 10 minutes and with 1% Sulfuric acid 96% (diluted 1:10 with water) for 60 minutes acts. A pH of 3.0 is established. In the same fleet, 4.8% CHROMOSAL BF added and with a running time overnight (8 hours) in Interval weighed. A pH of 3.7 is established. The fleet is drained Rinsed for 5 minutes with 30 ° C warm water. Then you wilt the leather and folds to 1 mm.

You put the leather back in the barrel and add 100% water, 40 ° C (% data from now on based on fold weight), 1% sodium formate and 1% sodium bicarbonate. After 45 minutes, the pH is adjusted to 4.9.

Then add 4% CHROMOSAL B and after 20 minutes 4% ENSUL AM 90 (with Water diluted 1: 4). After a running time of 60 minutes, the pH Value to 4.2.

The liquor is drained and washed in 300% water, 40 ° C, 10 minutes. In fresh liquor of 100% water, 40 ° C, 4% of the ester urethane 3 are added.  

After 30 minutes, 3% TANIGAN LN and 3% are added sweetened chestnut. After another 40 minutes, the pre-coloring with 2% follows TANIGAN FF-2N, 4% BAYGENAL gray S-GL and 0.4% BAYGENAL brown S- RL. After 60 minutes, pre-greasing with 4% EUREKA 800 FR (with water diluted 1: 4). After 30 minutes, the liquor is washed with 100% water 50 ° C increased. After 5 minutes, 2% formic acid (with water in a ratio of 1:10 diluted) in 2 installments within 15 minutes. A pH value of 3.0 a.

The fleet is drained. The main takes place in a new fleet, 100% water, 50 ° C greasing with 8% EUREKA 800 FR (diluted 1: 4 with water) in 45 Minutes. The fleet is drained.

In a new fleet, 200% water, 50 ° C, 2% BAYGENAL Gray S-GL and 0.2% BAYGENAL Brown S-RL overstained in 30 minutes. Then with 1% Formic acid (diluted 1:10 with water) to pH 2.9 in 30 minutes acidified.

The liquor is drained and rinsed with water at 25 ° C. for 5 minutes in the overflow. The leather is deposited on the trestle overnight, then stretched wet, air-dried, air-conditioned, stollen, grilled, stretched again and partly pulled judges.

Biodegradability test

The pieces of leather to be tested were first dried to constant weight and then clamped in 6 × 6 cm slide frames. Compost from a composting plant was filled 2 cm high in plastic dishes and the samples were placed in it. The ge filled boxes were placed in an incubator for 4 weeks in a row Incubated at 60, 50 and 37 ° C. Water losses were determined by weight loss true and balanced by adding distilled water. During the Incubation, the pH of the compost was measured once a week. To one batch was interrupted every 4 weeks, the samples were taken, cleaned,  dried at 80 ° C to constant weight and photographed. Immediately after When drying, the weight loss was determined by weighing again.

A material was said to be degradable if, like the one in a Pa parallel cellulose film completely disappeared or clear degradation showed.

Leather 1 was completely degraded after 3 months, leather 1.1 only 5%.

Example 2

A leather produced according to Example 1 is prepared according to the following method tet:

primer

50 g EUKANOL Black D and 150 g polyurethane dispersion 5 are mixed with 500 g Water mixed. This mixture is ge on the leather produced according to Example 1 sprays (3 (cross) spray orders (8/5/4 g / qfs)). Then another squirt trag (1 (cross) (4 g / qfs)), dried and at 80 ° C with 200 bar 6 Se customers ironed. Then one more cross (4 g / qfs) of the primer solution was carried in Spraying process on:

finish

100 g casein solution (from 13 g casein with 8 g aqueous ammonia and 79 g Water at 40 ° C an aqueous solution) are made with 30 g of the polyurethane added dispersion 5 and added 500 g of water. From this finishing solution one and a half cross (6 g / qfs) sprayed onto the primed leather. Then you spray one and a half cross after a 10% aqueous formalin solution, dry, iron at 80 ° C and 150 bar.

The leather so prepared withstood 20,000 wet kinks and 100,000 dry kinks (according to DIN 53 351) as well as 2,000 dry and 40 wet rubs (according to DIN 53 339) undamaged.  

Example 3

Coated split leather according to the invention can also be produced in an analogous manner produce that are also biodegradable.

Tanning method

Retanning mode of operation

Coating

Claims (6)

1. Process for the production of leather, according to which

• I. nakedness with
  • a) aldehydes or
  • b) bisulfite-blocked polyisocyanates (pre) tanned,
• II. Optionally with the product obtained
  • a) polyaspartic acid, its salts and / or its anhydrides and / or
  • b) polyaspartic acid amides (after) tanned,
• III.
  • a) priming the product obtained with polyurethane and auxiliary agents based on natural substances,
  • b) applying a finish made of polyurethane and / or polyester amide and
• IV. The leather thus treated, if necessary aftertreated with a leather preservative.

2. The method according to claim 1, according to which the tannins and auxiliaries used medium to at least 30% by weight according to DIN 54 900, part 3 (draft) bio are degradable. 3. Leather obtainable by the process according to claims 1 and 2.   4. Leather containing at least 30% by weight in accordance with DIN 54 900, part 3 (draft) are biodegradable and a shrinking temperature according to DIN 53 336 of have at least 65 ° C. 5. Leather according to claim 4, which has a shrinking temperature of at least 70 ° C. 6. Leather according to claim 4, which has a shrinking temperature of at least Have 80 ° C.