EP0061420A1 - Method of retanning leather with acrylic oligomers - Google Patents

Method of retanning leather with acrylic oligomers Download PDF

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Publication number
EP0061420A1
EP0061420A1 EP82810091A EP82810091A EP0061420A1 EP 0061420 A1 EP0061420 A1 EP 0061420A1 EP 82810091 A EP82810091 A EP 82810091A EP 82810091 A EP82810091 A EP 82810091A EP 0061420 A1 EP0061420 A1 EP 0061420A1
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Prior art keywords
parts
leather
oligomer
structural elements
formulas
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EP82810091A
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German (de)
French (fr)
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EP0061420B2 (en
EP0061420B1 (en
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Alain Dr. Lauton
Albert Dr. Würmli
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Novartis AG
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Ciba Geigy AG
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Priority claimed from CH152881A external-priority patent/CH646731A5/en
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C14—SKINS; HIDES; PELTS; LEATHER
    • C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
    • C14C3/00—Tanning; Compositions for tanning
    • C14C3/02—Chemical tanning
    • C14C3/28—Multi-step processes
    • C—CHEMISTRY; METALLURGY
    • C14—SKINS; HIDES; PELTS; LEATHER
    • C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
    • C14C3/00—Tanning; Compositions for tanning
    • C14C3/02—Chemical tanning
    • C14C3/08—Chemical tanning by organic agents
    • C14C3/22—Chemical tanning by organic agents using polymerisation products

Definitions

  • a method for retanning leather is known from US Pat. No. 4,150,944, in which a reaction product is used as the tanning agent, which is obtained by reacting one of e.g. Diphenyl ether,. Phenol and oleum of sulfonation product previously formed with e.g. Dimethylol urea or formaldehyde is available.
  • the present invention thus relates to a process for retanning chrome-tanned, optionally dyed leather, in which the leather is treated with an aqueous solution which contains an oligomer as the tanning agent, which contains structural elements of the formulas and if necessary or of the formulas (1), (2), (4) and optionally (3), in which X 1 is -CN, -COOR 1 , -OOCR 2 or -CONHR 3 , Y l -COOH or -COOM 2 , Y 2 -CONH 2 , -CH 2 OH, -OCH 3 or -OC 2 H 5 , Z 1 , Z 2 and Z 3 each hydrogen, methyl or ethyl, M and M 2 each an amine, ammonium or alkali metal cation and R 1 , R 2 and R 3 each denote alkyl, hydroxyalkyl or alkoxyalkyl with a total of at most 8 carbon atoms, and the treated leather greases and dries, before
  • the aqueous solution for carrying out the retanning process which contains the oligomer as the tanning agent, the leather retanned by the process and the use of the oligomer as the tanning agent form further objects of the invention.
  • the oligomers having structural elements of formulas (1), (2) and (4) are known per se and e.g. in U.S. Patent 3,646,099 as conductive and surface active compounds.
  • the oligomers which, in addition to the structural elements (1) and (2) additionally contain the structural element of the formula (3), are known from US Pat. No. 2,893,977 as a component of resin compositions with good adhesive properties.
  • oligomers are prepared in the presence of sulfites or hydrogen sulfites, they have structural elements of the formula (4) in one case and not in the other.
  • oligomers which are precipitated from their aqueous solutions by addition of strong acids, for example hydrochloric acid, after the known preparation has been completed in the presence of sulfites or hydrogen sulfites contain no or only traces of structural elements of the formula (4).
  • sulfite or hydrogen sulfite is present exclusively or at least mainly as a mixing component and not as a structural element of the oligomer in the form of the formula (4) in aqueous solution after the preparation of the oligomers has ended. Since oligomers reprecipitated with hydrochloric acid give the same results as non-reprecipitated oligomers when used as a tanning agent, the presence or absence of structural elements of the formula (4) does not constitute a critical feature of the oligomers used according to the invention. For the retanning process according to the invention, however, the oligomers used do not have to be reprecipitated before they are used.
  • the essential feature of the oligomers which can be used according to the invention is the relatively low, average molecular weight, which is preferably at most 14,000, especially 3,000 to 12,000 3,000 to 10,000, in particular 4,000 to 9,000.
  • These relatively low molecular weights of the oligomers used according to the invention compared to high molecular weight polymers which e.g. used in the plastics industry for the production of synthetic fibers are caused by the use of sulfites or hydroxysulfites in the production of oligomers.
  • preferred oligomers which are used as tanning agents in the process according to the invention each contain 2 to 75, preferably 5 to 40, in particular 10 to 25, structural elements of the formulas (1) and (2) and. 0 to 25, preferably 0 to 10, in particular 0 to 5 structural units of the formula (3).
  • oligomers come into consideration which, in addition to the structural elements of the formulas (2) and optionally (3), structural elements of the formula have, wherein X 2 -CN, -COOR 4 , -OOCR 5 or -CONHR 6 , R 4 alkyl, hydroxyalkyl or methoxyalkyl with a total of at most 4 carbon atoms, R 5 methyl or ethyl and R 6 alkyl having 1 to 8 carbon atoms or hydroxyalkyl 1 or 2 carbon atoms, and Z has the meanings given, and in particular structural elements of the formula where X 3 is -CN, -COOCH 3 , -COOC 2 H 5 , -COOC 2 H 4 OH, -COOC 3 H 6 OH, -COOC 2 H 4 OCH 3 , -O O CCH 3 , -OOCC 2 H 5 , -CONHCH 3 , -CONHC 2 H 5 , -CON
  • Structural elements of the formulas have structural elements which are particularly suitable as tanning agents and if necessary where X 4 is -CN, -COOCH 3 , -COOC 2 H 5 , -COOC 2 H 4 0H, -COOC 3 H 6 OH, -OOCCH 3 , -OOCC 2 H 5 , -CONHCH 3 , -CONHC 2 H 5 , -CONHC 3 H 7 and -CONHC 8 H 17 , Y 3 -COOH or -COOM 4 , Y 4 -CONH 2 , -CH 2 OH or -OCH 3 , M 3 and M 4 each a sodium, potassium or ammonium cation and Z 4 , Z 5 and Z 6 each represent hydrogen or methyl.
  • Oligomers which are of primary interest as tanning agents, have structural elements of the formulas and if necessary on.
  • the known oligomers are prepared by methods known per se, which are also described, for example, in US Pat. Nos. 3,646,099 and 3,893,977, by using the compounds of the formulas and if necessary wherein X 1 , Y 1 , Y 2 , Z 1 , Z 2 and Z 3 each have the meanings given, always in the presence of the compounds of the formulas in which M 1 has the meanings given, in an aqueous medium and, if appropriate, in the presence of a polymerization catalyst at a maximum of 70 ° C., and at this temperature the aqueous reaction mixture with a base of the formula wherein M 2 has the meanings given, to a pH of 5 to 7.
  • a polymerization catalyst such as azoisobutyronitrile or preferably peroxides, such as benzoyl peroxide or in particular ammonium peroxodisulfate (ie the compound of the formula (NH 4 ) 2 S 2 O 8 ) added to the aqueous solution of the starting compounds in portions, for example in 8 to 12 portions, or within 5 to 8 Hours metered continuously, an exothermic polymerization reaction sets in.
  • the reaction mixture is advantageously cooled in such a way that the temperature does not exceed 70 ° C., in particular 40 ° C.
  • the polymerization is generally complete 4 to 6 hours after the catalyst has been added.
  • the reaction mixture is adjusted to an appropriate pH of about 5 to 7, in particular 6.1 to 6.3, by adding the compound of the formula (10) with cooling so that the temperature indicated above is not exceeded. whereby an aqueous, gel-like solution of the copolymer is obtained.
  • the reaction mixture can, if necessary, for the complete removal of any unpolymerized starting compounds, in particular monomers of formula (5), for 6 to 10 hours under reduced pressure (-10 to -1 bar) at 60 can be kept up to 80 ° C.
  • sodium, potassium or ammonium sulphite or hydrogen sulfite are used as examples of specific representatives of the starting compounds of the formula (8 ) or (9), acrylonitrile, methacrylonitrile, ethyl acrylonitrile, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, methoxyethyl acrylate, vinyl acrylate, methyl propyl acrylamide, vinyl propyl acrylamide, methyl propyl acrylate, vinyl propyl acrylate, vinyl propyl acrylate, methyl propyl acrylate, vinyl propyl acrylate, vinyl propyl acrylate, vinyl propyl acrylate, methyl propyl acrylate, vinyl propyl acrylate, vinyl propyl acrylate, vinyl propy
  • retanning chrome-tanned leather it is expedient to proceed according to methods known per se by treating the leather with an aqueous solution which contains at least one oligomer of the type specified above, rinsing the tanned material in this way if necessary, and then generally greasing it and dries. If desired, coloring can be carried out before the greasing, provided that the leather to be retanned is not already colored.
  • 100 to 200, preferably 150 to 200 parts by weight of water and 2 to 50, in particular 5 to 10 parts by weight, calculated on dry substance, of at least one of the oligomers of the type mentioned are used per 100 parts by weight of leather.
  • Preferred aqueous solutions for carrying out the retanning process preferably contain 1 to 10, in particular 2 to 5, percent by weight of the oligomer as the tanning agent.
  • the leather is treated with the aqueous solution containing the oligomer for 1 to 4 hours at 10 ° C to 50 ° C, preferably 10 ° C to 30 ° C.
  • the undyed leather is dyed with commercially available leather dyes, for example acid or metal complex dyes
  • the dye is expediently used immediately after retanning by adding the dye of the stated type to the tanning liquor, so that in this case rinsing is generally not necessary.
  • the leather is not dyed, it is advantageous to subject the leather to a brief, for example 15 to 30 minute rinse with water at 10 ° C. to 50 ° C., preferably 10 ° C. to 30 ° C., after retanning.
  • the retanned, optionally dyed leather is then greased with a customary, preferably lightfast, fatliquor based on, for example, sulfonated sperm oil or claw oil.
  • This greasing is carried out for example at 30 ° C to 80 ° C for about 30 to 90 minutes.
  • a leather is obtained which has excellent lightfastness, a fine, compact, smooth grain and in particular a soft feel. With undyed leather a very light leather can also be obtained.
  • the strong bleaching effect achieved during retanning is particularly advantageous on uncoloured chrome leather.
  • the oligomers used as tanning agents according to the invention have excellent compatibility with other commercial tanning agents, for example vegetable tanning agents or synthetic retanning agents, so that the latter can be used together with the oligomers.
  • the so-called "wet blue” leather is particularly suitable as chrome-tanned leather, which can be retanned according to the invention, all types of leather, e.g. Calf, cow, goat or sheep leather are considered and the chrome-tanned leather before retanning according to the invention, as usual, as usual with e.g. Formates or bicarbonates is neutralized.
  • reaction mixture is used for the removal of unreacted acrylonitrile fractions under reduced pressure and inert for 2 hours Nitrogen atmosphere maintained.
  • the emulsion is then adjusted to a pH of 6 using 287.3 parts of a 30% strength aqueous sodium hydroxide solution (2.15 mol), the reaction mixture being cooled so that its temperature does not exceed 40.degree elevated.
  • 1000 parts of a light yellow, gel-like, clear, aqueous solution which contains 34% of an oligomer containing about 15 structural elements of the formula (1.4), about 15 structural elements of the formula (2.2) and traces of the structural element of the formula -S0 3 Na.
  • Instructions B The procedure described in Instructions A is followed, but a solution of 185.9 parts of acrylic acid (2.58 mol), 64.7 parts of acrylonitrile (1.22 mol) and 19.8 parts of the 40% sodium bisulfite Solution (0.076 mol) in 69.8 parts of water, which with a total of 19.8 parts of the ammonium peroxodisulfate solution in 10 portions, and after dilution with 96 parts of water, with 344 parts of the sodium hydroxide solution (2.58 mol) is moved.
  • Instructions C The procedure described in Instructions A is followed, but a solution of 185 parts of acrylic acid (2.56 mol), 34 parts of acrylonitrile (0.64 mol) and 55.6 parts of the sodium bisulfite solution (0.214 mol) is used in 257 Parts of water, which are mixed with a total of 10.7 parts of the ammonium peroxodisulfate solution in 10 portions and, after dilution with 116.4 parts of water, with 341.3 parts of the sodium hydroxide solution (2.56 mol).
  • Process D The procedure is as described in instruction A, but a solution of 138.3 parts of acrylic acid (1.92 mol), 127.3 parts of acrylonitrile (2.4 mol), 34.1 parts of acrylamide (0.48 mol ) and 41.6 parts of the sodium bisulfite solution (0.16 mol) in 298.4 parts of water, which together with a total of 11.4 parts of the ammonium peroxodisulfate solution in 10 portions and, after dilution with 92.9 parts of water, 256 parts of the sodium hydroxide solution (1.92 mol) are added.
  • Instructions E The procedure described in Instructions A is followed, but an emulsion of 211 parts of acrylic acid (2.92 mol), 141.5 parts of vinyl acetate (1.64 mol) and 43 parts of the 40% sodium bisulfite solution (0.165 mol ) in 80 ml of water, which, at 50 ° C., contains a total of 1.5 parts of ammonium peroxodisulfate in 25 ml of water in 10 portions and, after dilution with 155 parts of water, 320 parts of the sodium hydroxide solution (2.4 mol) becomes.
  • reaction mixture 146 parts of a 30% strength aqueous sodium hydroxide solution are then added to the reaction mixture over the course of about 1.5 hours in such a way that the temperature does not rise above 50.degree.
  • the reaction mixture is heated to reflux temperature (98-100 ° C.) and kept under a reduced pressure of -0.8 to -1.0 bar for about 8 hours at reflux temperature until a sample of the reaction mixture has less than 100 ppm unconverted acrylonitrile .
  • the reaction mixture is then cooled to 20 ° C. and adjusted to a pH of 6.1 to 6.3 by adding a total of about 22 parts of a 30% strength aqueous sodium hydroxide solution in portions.
  • About 600 parts of a clear, slightly yellowish solution are obtained which contains 33 to 34% of an oligomer which has 25 to 30 structural elements of the formulas (1.4) and (2.2).
  • Instructions G The procedure described in Instructions A is followed, but a solution of 128.4 parts of acrylic acid (1.78 mol), 144.2 parts of methacrylic acid hydroxypropyl ester (1 mol) and 47.4 parts of a 25% strength aqueous potassium hydrogen sulfite solution is used. Solution (0.1 mol) in 100 parts of water with a total of 10 parts of the ammonium peroxodisulfate solution in 10 portions at 60 ° C and, after dilution with 351.5 parts of water, with 218.5 parts of the sodium hydroxide solution (1.63 mol) is added.
  • Instructions H The procedure described in Instructions A is followed, but a solution of 73.6 parts of 2-ethoxyacrylic acid (0.51 mol), 93.8 parts of acrylic acid (1.30 mol) and 33.6 parts of a 25 %, aqueous potassium hydrogen sulfite solution (0.07 mol) in 60 parts of water, which with a total of 5 parts of the ammonium peroxodisulfate solution in 5 portions at 60 ° C and, after dilution with 565.8 parts of water, with 168, 2 parts of the sodium hydroxide solution (1.26 mol) is added.
  • Instructions I The procedure described in Instructions A is followed, but a solution of 130.7 parts of acrylic acid (1.81 mol), 120.3 parts of acrylonitrile (2.26 mol), 26.3 parts of allyl alcohol (0.40 mol ) and 72.6 parts of a 25% aqueous potassium hydrogen sulfite solution (0.15 mol) in 283.5 parts of water, which together with 37.8 parts of an ammonium peroxodisulfate solution in 5 portions and, after dilution with 87 parts Water, with 241.8 parts of the sodium hydroxide solution (1.81 mol) is added.
  • Instructions J The procedure described in Instructions A is followed, but a solution of 133 parts of acrylic acid (1.84 mol), 149.4 parts of methyl acrylate hydroxypropyl ester (1.03 mol) and 49 parts of a 25% strength aqueous potassium hydrogen sulfite solution (0 , 10 mol) in 98.4 parts of water, which with a total of 12.2 parts of the ammonium peroxodisulfate solution in 10 portions at 40 ° C. and, after dilution with 461.7 parts of water, with 96.3 parts of a 30% aqueous ammonia solution (1.7 mol) is added.
  • Example 1 100 parts of a chrome-tanned calfskin neutralized in a conventional manner are aftertreated with a solution of 200 parts of water and 5 parts, calculated on dry substance, of the oligomer according to specification A for 1 1/2 hours at 30 ° C. After a short rinse, the aftertreated leather is greased as usual with 4 to 6 parts of a lightfast fatliquor based on sulfonated sperm oil and then dried.
  • a leather of light color, excellent lightfastness, with a soft full grip and with a fine grain is obtained. This also applies to the replacement of 5 parts of the oligomer according to. Regulation A by 5 parts of the oligomer according to Regulation F.
  • Example 2 100 parts of chrome-tanned sheep leather are mixed with 200 parts of water at 40 ° C. Then 10 parts, calculated on dry substance, of an oligomer according to regulation B are added to the liquor and left to act on the leather for 2 hours at 40 ° C. After rinsing, the treated leather is greased with about 5 parts of a conventional fatliquor and then dried. You get a full, supple leather with a closed, firmly adhering scars. This also applies to the replacement of -10 parts of the oligomer according to regulation B by 10 parts of the oligomer according to regulation C.
  • Example 3 100 g of chrome-cooked, folded cowhide leather is neutralized in a barrel in 200 parts of liquor in a known manner to such an extent that the pH of the leather remains below 4 on average.
  • the bath is then mixed with 6 parts, calculated on dry substance, of the terpolymer according to regulation D and the neutralized leather is treated at 45 ° C for 2 hours.
  • a fresh liquor 300 parts
  • 1 part of the dye of the formula the leather is dyed at 60 ° C for 30 minutes.
  • the leather is now stretched out and dried.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Treatment And Processing Of Natural Fur Or Leather (AREA)

Abstract

Oligomere mit Strukturelementen der Formeln <IMAGE> und gegebenenfalls <IMAGE> worin X -CH, -COOR, -OOCR oder -CONHR, Y1 -COOH oder -COOM, Y2 -CONH2-, -CH2OCH, -OCH3 oder -OC2H5, Z -H, -CH3 oder -C2H5, M ein Amin-, Ammonium- oder Alkalimetallkation und R Alkyl, Hydroxyalkyl oder Alkoxyalkyl mit höchstens 8 Kohlenstoffatomen bedeuten, sind geeignet, in einem Verfahren zum Nachgerben von chromgegerbtem Leder eingesetzt zu werden. Die Oligomeren werden durch Mischpolymerisation der den Strukturelementen der angegebenen Formlen entsprechenden Comonomere der Acrylsäurereihe in Gegenwart von Sulfiten oder Hydrogensulfiten der Formeln SO3(M)2 oder HSO3M hergestellt und weisen ein durchschnittliches Molekulargewicht von höchstens 14'000 auf.Oligomers with structural elements of the formulas <IMAGE> and optionally <IMAGE> in which X is -CH, -COOR, -OOCR or -CONHR, Y1 -COOH or -COOM, Y2 -CONH2-, -CH2OCH, -OCH3 or -OC2H5, Z - H, -CH3 or -C2H5, M is an amine, ammonium or alkali metal cation and R is alkyl, hydroxyalkyl or alkoxyalkyl having at most 8 carbon atoms, are suitable for use in a process for retanning chrome-tanned leather. The oligomers are prepared by copolymerization of the comonomers of the acrylic acid series corresponding to the structural elements of the formulas given in the presence of sulfites or hydrogen sulfites of the formulas SO3 (M) 2 or HSO3M and have an average molecular weight of at most 14,000.

Description

Aus der US Patentschrift 4 150 944 ist ein Verfahren zum Nachgerben von Leder bekannt, bei welchem als Gerbstoff ein Umsetzungsprodukt eingesetzt wird, das durch Umsetzung eines aus z.B. Diphenyläther, . Phenol und Oleum vorgängig gebildeten Sulfonierungsproduktes mit z.B. Dimethylolharnstoff oder Formaldehyd erhältlich ist.A method for retanning leather is known from US Pat. No. 4,150,944, in which a reaction product is used as the tanning agent, which is obtained by reacting one of e.g. Diphenyl ether,. Phenol and oleum of sulfonation product previously formed with e.g. Dimethylol urea or formaldehyde is available.

Es wurde nun gefunden, dass zum Nachgerben von Leder anstelle des Umsetzungsproduktes der angegebenen Art ein besonders leicht zugängliches Oligomer mit mindestens ebenbürtiger, gerbender Wirkung vorteilhafterweise eingesetzt werden kann.It has now been found that a particularly easily accessible oligomer with an at least equal, tanning effect can advantageously be used for retanning leather instead of the reaction product of the type indicated.

Gegenstand der vorliegenden Erfindung ist somit ein Verfahren zum Nachgerben von chromgegerbtem, gegebenenfalls gefärbtem Leder, bei welchem man das Leder mit einer wässrigen Lösung behandelt, die als Gerbstoff ein Oligomer enthält, welches Strukturelemente der Formeln

Figure imgb0001
und gegebenenfalls
Figure imgb0002
oder der Formeln (1), (2), (4) und gegebenenfalls (3) aufweist, worin X1 -CN, -COOR1, -OOCR2 oder -CONHR3, Yl -COOH oder -COOM2, Y2 -CONH2, -CH2OH, -OCH3 oder -OC2H5, Z1, Z2 und Z3 je Wasserstoff, Methyl oder Aethyl, M und M2 je ein Amin-, Ammonium- oder Alkalimetall-Kation und R1, R2 und R3 je Alkyl, Hydroxyalkyl oder Alkoxyalkyl mit insgesamt höchstens 8 Kohlenstoffatomen bedeuten, und das behandelte Leder fettet und trocknet, wobei vor oder nach dem Fetten das behandelte Leder gegebenenfalls noch gefärbt wird.The present invention thus relates to a process for retanning chrome-tanned, optionally dyed leather, in which the leather is treated with an aqueous solution which contains an oligomer as the tanning agent, which contains structural elements of the formulas
Figure imgb0001
 and if necessary
Figure imgb0002
 or of the formulas (1), (2), (4) and optionally (3), in which X 1 is -CN, -COOR 1 , -OOCR 2 or -CONHR 3 , Y l -COOH or -COOM 2 , Y 2 -CONH 2 , -CH 2 OH, -OCH 3 or -OC 2 H 5 , Z 1 , Z 2 and Z 3 each hydrogen, methyl or ethyl, M and M 2 each an amine, ammonium or alkali metal cation and R 1 , R 2 and R 3 each denote alkyl, hydroxyalkyl or alkoxyalkyl with a total of at most 8 carbon atoms, and the treated leather greases and dries, before or after the Grease the treated leather, if necessary, is also dyed.

Die wässrige Lösung zur Durchführung des Nachgerbeverfahrens, die das Oligomer als Gerbstoff enthält, das nach dem Verfahren nachgegerbte Leder und die Verwendung des Oligomers als Gerbstoff bilden weitere Gegenstände derivorliegenden Erfindung.The aqueous solution for carrying out the retanning process, which contains the oligomer as the tanning agent, the leather retanned by the process and the use of the oligomer as the tanning agent form further objects of the invention.

Die Oligomere, die Strukturelemente der Formeln (1), (2) und (4) aufweisen, sind an sich bekannt und z.B. in der US-Patentschrift 3 646 099 als leitfähige und oberflächenaktive Verbindungen beschrieben. Ebenfalls sind die Oligomere, die neben den Strukturelementen (1) und (2) zusätzlich das Strukturelement der Formel (3) enthalten, aus der US-Patentschrift 2 893 977 als Komponente von Harzzusammensetzungen mit guten Hafteigenschaften bekannt.The oligomers having structural elements of formulas (1), (2) and (4) are known per se and e.g. in U.S. Patent 3,646,099 as conductive and surface active compounds. The oligomers which, in addition to the structural elements (1) and (2) additionally contain the structural element of the formula (3), are known from US Pat. No. 2,893,977 as a component of resin compositions with good adhesive properties.

Obwohl in den beiden genannten Patentschriften die Oligomere in Gegenwart von Sulfiten oder Hydrogensulfiten hergestellt werden, weisen sie in einem Fall Strukturelemente der Formel (4) auf, im anderen Fall nicht. Aufgrund analytischer Untersuchungen enthalten Oligomere, die nach beendeter, bekannter Herstellung in Gegenwart von Sulfiten oder Hydrogensulfiten durch Zusatz von starken Säuren, z.B. Salzsäure, aus ihren wässrigen Lösungen gefällt werden, keine oder nur Spuren an Strukturelementen der Formel (4). Es muss daher angenommen werden, dass Sulfit oder Hydrogensulfit nach beendeter Herstellung der Oligomere, in wässriger Lösung ausschliesslich oder mindestens hauptsächlich als Mischungskomponente und nicht als Strukturelement des Oligomers in Form der Formel (4) vorhanden ist. Da mit Salzsäure umgefällte Oligomere bei ihrer Verwendung als Gerbstoff gleiche Resultate ergeben wie nicht umgefällte Oligomere, bildet die Gegenwart oder Abwesenheit von Strukturelementen der Formel (4) kein kritisches Merkmal der erfindungsgemäss verwendeten Oligomere. Für das erfindungsgemässe Nachgerbverfahren brauchen aber die verwendeten Oligomere vor ihrem Einsatz nicht umgefällt zu werden.Although in the two cited patents the oligomers are prepared in the presence of sulfites or hydrogen sulfites, they have structural elements of the formula (4) in one case and not in the other. On the basis of analytical investigations, oligomers which are precipitated from their aqueous solutions by addition of strong acids, for example hydrochloric acid, after the known preparation has been completed in the presence of sulfites or hydrogen sulfites contain no or only traces of structural elements of the formula (4). It must therefore be assumed that sulfite or hydrogen sulfite is present exclusively or at least mainly as a mixing component and not as a structural element of the oligomer in the form of the formula (4) in aqueous solution after the preparation of the oligomers has ended. Since oligomers reprecipitated with hydrochloric acid give the same results as non-reprecipitated oligomers when used as a tanning agent, the presence or absence of structural elements of the formula (4) does not constitute a critical feature of the oligomers used according to the invention. For the retanning process according to the invention, however, the oligomers used do not have to be reprecipitated before they are used.

Wesentliches Merkmal der erfindungsgemäss verwendbaren Oligomere ist neben der Gegenwart der Strukturelemente der Formeln (1), (2) und gegebenenfalls (3) das relativ niedrige, durchschnittliche Molekulargewicht, das höchstens 14'000, vor allem 3'000 bis 12'000, vorzugsweise 3'000 bis 10'000, insbesondere 4'000 bis 9'000 beträgt. Diese relativ niedrigen Molekulargewichte der erfindungsgemäss verwendeten Oligomere im Vergleich zu hochmolekularen Polymeren, die z.B. in der Kunststoffindustrie zur Herstellung von Synthesefasern Verwendung finden, werden durch den Einsatz von Sulfiten oder Hydroxysulfiten bei der Oligomerherstellung bedingt.In addition to the presence of the structural elements of the formulas (1), (2) and optionally (3), the essential feature of the oligomers which can be used according to the invention is the relatively low, average molecular weight, which is preferably at most 14,000, especially 3,000 to 12,000 3,000 to 10,000, in particular 4,000 to 9,000. These relatively low molecular weights of the oligomers used according to the invention compared to high molecular weight polymers which e.g. used in the plastics industry for the production of synthetic fibers are caused by the use of sulfites or hydroxysulfites in the production of oligomers.

Aufgrund ihrer durchschnittlichen Molekulargewichte enthalten bevorzugte Oligomere, die im erfindungsgemässen Verfahren als Gerbstoff eingesetzt werden, je 2 bis 75, vorzugsweise 5 bis 40, insbesondere 10 bis 25 Strukturelemente der Formeln (1) und (2) und. 0 bis 25, vorzugsweise 0 bis 10, insbesondere 0 bis 5 Struktureinheiten der Formel (3).Because of their average molecular weights, preferred oligomers which are used as tanning agents in the process according to the invention each contain 2 to 75, preferably 5 to 40, in particular 10 to 25, structural elements of the formulas (1) and (2) and. 0 to 25, preferably 0 to 10, in particular 0 to 5 structural units of the formula (3).

Vor allem kommen im Hinblick auf ihren Einsatz als Gerbstoff Oligomere in Betracht, die neben den Strukturelementen der Formeln (2) und gegebenenfalls (3) Strukturelemente der Formel

Figure imgb0003
aufweisen, worin X2 -CN, -COOR4, -OOCR5 oder -CONHR6, R4 Alkyl, Hydroxyalkyl oder Methoxyalkyl mit insgesamt höchstens 4 Kohlenstoffatomen, R5 Methyl oder Aethyl und R6 Alkyl mit 1 bis 8 Kohlenstoffatomen oder Hydroxyalkyl mit 1 oder 2 Kohlenstoffatomen bedeuten, und Z die angegebenen Bedeutungen hat, und insbesondere Strukturelemente der Formel
Figure imgb0004
aufweisen, worin X3 -CN, -COOCH3, -COOC2H5, -COOC2H4OH, -COOC3H6OH, -COOC2H4OCH3, -OOCCH3, -OOCC2H5, -CONHCH3, -CONHC2H5, -CONHCH2OH, -CONHC3H7, -CONHC8H17 bedeutet und Z1 die angegebenen Bedeutungen hat.Above all, with regard to their use as tanning agents, oligomers come into consideration which, in addition to the structural elements of the formulas (2) and optionally (3), structural elements of the formula
Figure imgb0003
 have, wherein X 2 -CN, -COOR 4 , -OOCR 5 or -CONHR 6 , R 4 alkyl, hydroxyalkyl or methoxyalkyl with a total of at most 4 carbon atoms, R 5 methyl or ethyl and R 6 alkyl having 1 to 8 carbon atoms or hydroxyalkyl 1 or 2 carbon atoms, and Z has the meanings given, and in particular structural elements of the formula
Figure imgb0004
 where X 3 is -CN, -COOCH 3 , -COOC 2 H 5 , -COOC 2 H 4 OH, -COOC 3 H 6 OH, -COOC 2 H 4 OCH 3 , -O O CCH 3 , -OOCC 2 H 5 , -CONHCH 3 , -CONHC 2 H 5 , -CONHCH 2 OH, -CONHC 3 H 7 , -CONHC 8 H 17 and Z 1 has the meanings given.

Als Gerbstoff besonders geeignete Oligomere weisen Strukturelemente der Formeln

Figure imgb0005
und gegebenenfalls
Figure imgb0006
auf, worin X4 -CN, -COOCH3, -COOC2H5, -COOC2H40H, -COOC3H6OH, -OOCCH3, -OOCC2H5, -CONHCH3, -CONHC2H5, -CONHC3H7 und -CONHC8H17, Y3 -COOH oder -COOM4, Y4 -CONH2, -CH2OH oder -OCH3, M3 und M4 je ein Natrium-, Kalium- oder Ammoniumkation und Z4, Z5 und Z6 je Wasserstoff oder Methyl bedeuten.Structural elements of the formulas have structural elements which are particularly suitable as tanning agents
Figure imgb0005
 and if necessary
Figure imgb0006
 where X 4 is -CN, -COOCH 3 , -COOC 2 H 5 , -COOC 2 H 4 0H, -COOC 3 H 6 OH, -OOCCH 3 , -OOCC 2 H 5 , -CONHCH 3 , -CONHC 2 H 5 , -CONHC 3 H 7 and -CONHC 8 H 17 , Y 3 -COOH or -COOM 4 , Y 4 -CONH 2 , -CH 2 OH or -OCH 3 , M 3 and M 4 each a sodium, potassium or ammonium cation and Z 4 , Z 5 and Z 6 each represent hydrogen or methyl.

Oligomere, die als Gerbstoff im Vordergrund des Interesses stehen, weisen Strukturelemente der Formeln

Figure imgb0007
und gegebenenfalls
Figure imgb0008
auf.Oligomers, which are of primary interest as tanning agents, have structural elements of the formulas
Figure imgb0007
 and if necessary
Figure imgb0008
 on.

Die Herstellung der bekannten Oligomere wird nach an sich bekannten Methoden durchgeführt, die ebenfalls z.B. in den US-Patentschriften 3 646 099 und 3 893 977 beschrieben sind, indem man die Verbindungen der Formeln

Figure imgb0009
und gegebenenfalls
Figure imgb0010
worin X 1, Y1, Y2, Z1, Z2 und Z3 jeweils die angegebenen Bedeutungen haben, stets in Gegenwart der Verbindungen der Formeln
Figure imgb0011
worin M1 die angegebenen Bedeutungen hat, in.wässrigem Medium und gegebenenfalls in Gegenwart eines Polymerisations-Katalysators bei höchstens 70°C umsetzt, und bei dieser Temperatur das wässrige Reaktionsgemisch mit einer Base der Formel
Figure imgb0012
worin M2 die angegebenen Bedeutungen hat, auf einen pH-Wert von 5 bis 7 einstellt.The known oligomers are prepared by methods known per se, which are also described, for example, in US Pat. Nos. 3,646,099 and 3,893,977, by using the compounds of the formulas
Figure imgb0009
 and if necessary
Figure imgb0010
 wherein X 1 , Y 1 , Y 2 , Z 1 , Z 2 and Z 3 each have the meanings given, always in the presence of the compounds of the formulas
Figure imgb0011
 in which M 1 has the meanings given, in an aqueous medium and, if appropriate, in the presence of a polymerization catalyst at a maximum of 70 ° C., and at this temperature the aqueous reaction mixture with a base of the formula
Figure imgb0012
 wherein M 2 has the meanings given, to a pH of 5 to 7.

Vorzugsweise werden je 2 bis 75, vor allem 5 bis 40 und insbesondere 10 bis 25 Mol der Ausgangsmonomere (5), (6) und gegebenenfalls (7) pro Mol bzw. pro Aequivalent der Ausgangsverbindungen der Formeln (8) bzw. (9) vorgelegt, wobei in der Regel zuerst die Komponente (5) und dann die Komponente (6) und gegebenenfalls (7) eingesetzt werden, um eine Homopolymerisation der im allgemeinen reaktiveren Komponente (6) zu vermeiden, dann den vorgelegten Monomeren kleine Mengen (z.B. 1/20 bis 1/5 der Totalmenge an Ausgangsverbindungen der Formeln (5) bis (9)) eines Polymerisationskatalysators, wie Azoisobutyronitril oder vorzugsweise Peroxyde, wie Benzoylperoxyd oder insbesondere Ammoniumperoxodisulfat (d.h. der Verbindung der Formel (NH4)2S2O8) der wässrigen Lösung der Ausgangsverbindungen portionsweise, z.B. in 8 bis 12 Portionen zugesetzt, oder innerhalb von 5 bis 8 Stunden kontinuierlich zudosiert, wobei eine exotherme Polymerisationsreaktion einsetzt. Vorteilhafterweise wird das Reaktionsgemisch so gekühlt, dass die Temperatur von 70°C, insbesondere 40°C nicht überschritten wird. Bei bevorzugten Temperaturen von 50 bis 55°C ist die Polymerisation in der Regel 4 bis 6 Stunden nach der Katalysatorzugabe beendet. Nach beendeter Polymerisation wird das Reaktionsgemisch durch Zugabe der Verbindung der Formel (10) unter Kühlen, so dass die vorstehend angegebene Temperatur nicht überschritten wird, auf einen zweckmässigen pH-Wert von etwa 5 bis 7, insbesondere 6,1 bis 6,3 eingestellt, wobei eine wässrige, gelartige Lösung des Copolymers erhalten wird. Nach der Zugabe der Verbindung der Formel (10) kann nötigenfalls das Reaktionsgemisch zur vollständigen Entfernung von gegebenenfalls nicht polymerisierten Ausgangsverbindungen, insbesondere von Monomeren der Formel (5), während 6 bis 10 Stunden unter vermindertem Druck (-10 bis -1 bar) bei 60 bis 80°C gehalten werden.2 to 75, in particular 5 to 40 and in particular 10 to 25 moles of the starting monomers (5), (6) and optionally (7) are preferably used per mole or per equivalent of the starting compounds of the formulas (8) or (9) submitted, usually first component (5) and then component (6) and optionally (7) are used to avoid homopolymerization of the generally more reactive component (6), then small amounts of the monomers (e.g. 1st / 20 to 1/5 of the total amount of starting compounds of the formulas (5) to (9)) of a polymerization catalyst, such as azoisobutyronitrile or preferably peroxides, such as benzoyl peroxide or in particular ammonium peroxodisulfate (ie the compound of the formula (NH 4 ) 2 S 2 O 8 ) added to the aqueous solution of the starting compounds in portions, for example in 8 to 12 portions, or within 5 to 8 Hours metered continuously, an exothermic polymerization reaction sets in. The reaction mixture is advantageously cooled in such a way that the temperature does not exceed 70 ° C., in particular 40 ° C. At preferred temperatures of 50 to 55 ° C., the polymerization is generally complete 4 to 6 hours after the catalyst has been added. After the polymerization has ended, the reaction mixture is adjusted to an appropriate pH of about 5 to 7, in particular 6.1 to 6.3, by adding the compound of the formula (10) with cooling so that the temperature indicated above is not exceeded. whereby an aqueous, gel-like solution of the copolymer is obtained. After the addition of the compound of formula (10), the reaction mixture can, if necessary, for the complete removal of any unpolymerized starting compounds, in particular monomers of formula (5), for 6 to 10 hours under reduced pressure (-10 to -1 bar) at 60 can be kept up to 80 ° C.

So werden z.B. zur Herstllung eines Terpolymers, das Strukturelemente der Formeln (1.2), (2.1), (3.1) und gegebenenfalls (4.1) aufweist, Natrium-, Kalium- oder Ammoniumsülfit oder -hydrogensulfit als Beispiele spezifischer Vertreter der Ausgangsverbindungen der Formel (8) oder (9), Acrylnitril, Methacrylnitril, Aethylacrylnitril, Methylacrylat, Aethylacrylat, Methylmethacrylat, Aethylmethacrylat, Hydroxyäthylacrylat, Hydroxyäthylmethacrylat, Hydroxypropylacrylat, Hydroxypropylmethacrylat, Methoxyäthylacrylat, Vinylacetat, Vinylpropionat, N-Methylacrylamid, N-Aethylacrylamid, N-Methylolacrylamid, N-Isopropylacrylamid oder N-Isooctylacrylamid als Beispiele spezifischer Vertreter des Monomers der Formel (5), Acrylsäure, Methacrylsäure oder a-Aethylacrylsäure als Beispiele spezifischer Vertreter des Monomers der Formel (6) und Acrylamid, Methacrylamid, Vinylmethyl- äther oder Allylalkohol als Beispiele spezifischer Vertreter des Monomers der Formel (7) miteinander mischpolymerisiert und anschliessend mit Natriumhydroxyd, Kaliumhydroxyd oder Ammoniak als Beispiele spezifischer Vertreter der Base der Formel (10) neutralisiert.For example, for the production of a terpolymer which has structural elements of the formulas (1.2), (2.1), (3.1) and optionally (4.1), sodium, potassium or ammonium sulphite or hydrogen sulfite are used as examples of specific representatives of the starting compounds of the formula (8 ) or (9), acrylonitrile, methacrylonitrile, ethyl acrylonitrile, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, methoxyethyl acrylate, vinyl acrylate, methyl propyl acrylamide, vinyl propyl acrylamide, methyl propyl acrylate, vinyl propyl acrylate, vinyl propyl acrylate, methyl propyl acrylate, vinyl propyl acrylate, vinyl propyl acrylate, vinyl propyl acrylate, methyl propyl acrylate, vinyl propyl acrylate, vinyl propyl acrylate, vinyl propyl acrylate, vinyl propyl acrylate, methyl propyl N-isooctylacrylamide as examples of specific representatives of the monomer of formula (5), acrylic acid, methacrylic acid or α-ethyl acrylic acid as examples of specific representatives of the monomer of formula (6) and acrylamide, methacrylamide, vinyl methyl ether or allyl alcohol as examples of specific representatives of the monomer of Formula (7) copolymerized with one another and ansc neutralized with sodium hydroxide, potassium hydroxide or ammonia as examples of specific representatives of the base of formula (10).

Beim Nachgerben von chromgegerbtem Leder geht man nach an sich bekannten Methoden zweckmässig so vor, dass man das Leder mit einer wässrigen Lösung, die mindestens ein Oligomer der vorstehend angegebenen Art enthält, behandelt, das so gegerbte Material gegebenenfalls nachspült, und in der Regel anschliessend fettet und trocknet. Wenn erwünscht, kann vor der Fettung eine Färbung durchgeführt werden, sofern das eingesetzte nachzugerbende Leder nicht bereits gefärbt ist. In der Regel werden auf 100 Gewichtsteile Leder 100 bis 200, vorzugsweise 150 bis 200 Gewichtsteile Wasser und 2 bis 50, insbesondere 5 bis 10 Gewichtsteile, berechnet auf Trockensubstanz, mindestens einer der Oligomere der angegebenen Art eingesetzt.When retanning chrome-tanned leather, it is expedient to proceed according to methods known per se by treating the leather with an aqueous solution which contains at least one oligomer of the type specified above, rinsing the tanned material in this way if necessary, and then generally greasing it and dries. If desired, coloring can be carried out before the greasing, provided that the leather to be retanned is not already colored. As a rule, 100 to 200, preferably 150 to 200 parts by weight of water and 2 to 50, in particular 5 to 10 parts by weight, calculated on dry substance, of at least one of the oligomers of the type mentioned are used per 100 parts by weight of leather.

Bevorzugte wässrige Lösungen zur Durchführung des Nachgerbeverfahrens enthalten indessen vorzugsweise 1 bis 10, insbesondere 2 bis 5 Gewichtsprozent des Oligomers als Gerbstoff.Preferred aqueous solutions for carrying out the retanning process, however, preferably contain 1 to 10, in particular 2 to 5, percent by weight of the oligomer as the tanning agent.

Im allgemeinen wird das Leder mit der wässrigen Lösung, die das Oligomer enthält, wärhend 1-bis 4 Stunden bei 10°C bis 50°C, vorzugsweise 10°C bis 30°C behandelt. Sofern eine Färbung des ungefärbten Leders mit handelsüblichen Lederfarbstoffen, z.B. Säure- oder Metallkomplexfarbstoffen vorgenommen wird, wird der Farbstoff zweckmässigerweise unmittelbar nach dem Nachgerben durch Zusatz des Farbstoffes der angegebenen Art in die Gerbeflotte eingesetzt, so dass in diesem Falle die Nachspülung in der Regel entfällt. Falls hingegen das Leder nicht gefärbt wird, ist es vorteilhaft, das Leder nach dem Nachgerben einer kurzen, z.B. 15- bis 30-minütigen Spülung mit Wasser bei 10°C bis 50°C, vorzugsweise 10°C bis 30°C zu unterwerfen. Anschliessend wird das nachgegerbte, gegebenenfalls gefärbte Leder mit einem üblichen, vorzugsweise lichtechten Fettungsmittel auf der Basis von z.B. sulfoniertem Spermöl oder Klauenöl gefettet. Diese Fettung wird z.B. bei 30°C bis 80°C während etwa 30 bis 90 Minuten durchgeführt. Nach dem Trocknen bei etwa 30°C bis 80°C erhält man ein Leder, welches eine ausgezeichnete Lichtechtheit, einen feinen kompakten, glatten Narben und insbesondere einen weichen Griff aufweist. Bei ungefärbtem Leder kann zudem ein sehr helles Leder erhalten werden. Speziell auf ungefärbtem Chromleder ist die bei der Nachgerbung erzielte, starke Bleichwirkung besonders vorteilhaft. Zudem weisen die als Gerbstoffe erfindungsgemäss verwendeten Oligomere eine ausgezeichnete Kompatibilität mit anderen handelsüblichen Gerbstoffen, z.B. vegetabilischen Gerbstoffen oder synthetischen Nachgerbstoffen auf, so dass letztere zusammen mit den Oligomeren eingesetzt werden können.In general, the leather is treated with the aqueous solution containing the oligomer for 1 to 4 hours at 10 ° C to 50 ° C, preferably 10 ° C to 30 ° C. If the undyed leather is dyed with commercially available leather dyes, for example acid or metal complex dyes, the dye is expediently used immediately after retanning by adding the dye of the stated type to the tanning liquor, so that in this case rinsing is generally not necessary. If, on the other hand, the leather is not dyed, it is advantageous to subject the leather to a brief, for example 15 to 30 minute rinse with water at 10 ° C. to 50 ° C., preferably 10 ° C. to 30 ° C., after retanning. The retanned, optionally dyed leather is then greased with a customary, preferably lightfast, fatliquor based on, for example, sulfonated sperm oil or claw oil. This greasing is carried out for example at 30 ° C to 80 ° C for about 30 to 90 minutes. After drying at about 30 ° C to 80 ° C, a leather is obtained which has excellent lightfastness, a fine, compact, smooth grain and in particular a soft feel. With undyed leather a very light leather can also be obtained. The strong bleaching effect achieved during retanning is particularly advantageous on uncoloured chrome leather. In addition, the oligomers used as tanning agents according to the invention have excellent compatibility with other commercial tanning agents, for example vegetable tanning agents or synthetic retanning agents, so that the latter can be used together with the oligomers.

Als chromgegerbtes Leder, das erfindungsgemäss nachgegerbt werden kann, eignen sich vor allem die sogenannten "wet blue"-Leder, wobei alle Lederarten, z.B. Kalbs-, Rind-, Ziegen- oder Schafsleder in Betracht fallen und das chromgegerbte Leder vor dem erfindüngsgemässen Nachgerben in der Regel wie üblich mit z.B. Formiaten oder Bicarbonaten neutralisiert wird.The so-called "wet blue" leather is particularly suitable as chrome-tanned leather, which can be retanned according to the invention, all types of leather, e.g. Calf, cow, goat or sheep leather are considered and the chrome-tanned leather before retanning according to the invention, as usual, as usual with e.g. Formates or bicarbonates is neutralized.

Die Prozente und Teile in den nachfolgenden Beispielen sind Gewichtseinheiten.The percentages and parts in the examples below are units by weight.

Herstellungsvorschriften für OligomereManufacturing instructions for oligomers

Vorschrift A: Eine Lösung von 165,3 Teilen Acrylsäure (2,29 Mol), 122,0 Teilen Acrylnitril (2,29 Mol) und 39,8 Teilen einer 40%-igen, wässrigen Natriumhydrogensulfit-Lösung (0,153 Mol) in 280 Teilen entionisiertem Wasser wird auf 29°C geheizt. In diese Lösung werden lOmal jede 1/4 Stunde jeweils 0,96 Teile (d.h. insgesamt 9,6 Teile innerhalb von 2 1/2 Stunden) einer 1%-igen, wässrigen Ammoniumperoxodisulfat-Lösung zugegeben, wobei das Reaktionsgemisch so gekühlt wird, dass es sich nach jeder Zugabe auf höchstens 34°C erwärmt. Die so erhaltene, weisse Emulsion wird alsdann mit 96 Teilen entionisiertem Wasser verdünnt. Anschliessend wird das Reaktionsgemisch auf 20°C abgekühlt und 7 Stunden bei dieser Temperatur gehalten. Nach dieser Zeit wird das Reaktionsgemisch zur Entfernung von nicht-umgesetzten Acrylnitrilanteilen während 2 Stunden unter vermindertem Druck und inerter Stickstoffatmosphäre gehalten. Danach wird die Emulsion mit 287,3 Teilen einer 30%-igen, wässrigen Natriumhydroxyd-Lösung (2,15 Mol) auf einen pH-Wert von 6 gestellt, wobei das Reaktionsgemisch so gekühlt wird, dass sich dessen Temperatur nicht über 40°C erhöht. Nach dem Kühlen des Reaktionsgemisches auf 20°C erhält man 1000 Teile einer hellgelben, gelartigen, klaren, wässrigen Lösung, die 34% eines Oligomers enthält, das etwa 15 Strukturelemente der Formel (1.4), etwa 15 Strukturelemente der Formel (2.2) und Spuren des Strukturelementes der Formel -S03Na aufweist.Instructions A: A solution of 165.3 parts of acrylic acid (2.29 mol), 122.0 parts of acrylonitrile (2.29 mol) and 39.8 parts of a 40% aqueous sodium bisulfite solution (0.153 mol) in 280 Parts of deionized water are heated to 29 ° C. 0.96 parts (ie a total of 9.6 parts within 2 1/2 hours) of a 1% strength aqueous ammonium peroxodisulfate solution are added to this solution 10 times every 1/4 hour, the reaction mixture being cooled such that it warms up to a maximum of 34 ° C after each addition. The white emulsion so obtained is then diluted with 96 parts of deionized water. The reaction mixture is then cooled to 20 ° C. and kept at this temperature for 7 hours. After this time, the reaction mixture is used for the removal of unreacted acrylonitrile fractions under reduced pressure and inert for 2 hours Nitrogen atmosphere maintained. The emulsion is then adjusted to a pH of 6 using 287.3 parts of a 30% strength aqueous sodium hydroxide solution (2.15 mol), the reaction mixture being cooled so that its temperature does not exceed 40.degree elevated. After cooling the reaction mixture to 20 ° C, 1000 parts of a light yellow, gel-like, clear, aqueous solution which contains 34% of an oligomer containing about 15 structural elements of the formula (1.4), about 15 structural elements of the formula (2.2) and traces of the structural element of the formula -S0 3 Na.

Vorschrift B: Man verfährt wie in Vorschrift A angegeben, setzt jedoch eine Lösung aus 185,9 Teilen Acrylsäure (2,58 Mol), 64,7 Teilen Acrylnitril (1,22 Mol) und 19,8 Teilen der 40%igen Natriumhydrogensulfit-Lösung (0,076 Mol) in 69,8 Teilen Wasser ein, die mit insgesamt 19,8 Teilen der Ammoniumperoxodisulfat-Lösung in 10 Portionen,und nach der Verdünnung mit 96 Teilen Wasser,mit 344 Teilen der Natriumhydroxyd- Lösung (2,58 Mol) versetzt wird. Man erhält 1000 Teile einer hellgelben, gelartigen, klaren, wässrigen Lösung, die 31% eines Oligomers enthält, das etwa 16 Strukturelemente der Formel (1.4), etwa 34 Strukturelemente der Formel (2.2) und Spuren des Strukturelementes der Formel -S03Na aufweist.Instructions B: The procedure described in Instructions A is followed, but a solution of 185.9 parts of acrylic acid (2.58 mol), 64.7 parts of acrylonitrile (1.22 mol) and 19.8 parts of the 40% sodium bisulfite Solution (0.076 mol) in 69.8 parts of water, which with a total of 19.8 parts of the ammonium peroxodisulfate solution in 10 portions, and after dilution with 96 parts of water, with 344 parts of the sodium hydroxide solution (2.58 mol) is moved. This gives 1000 parts of a light yellow, gel-like, clear, aqueous solution which contains 31% of an oligomer which has about 16 structural elements of the formula (1.4), about 34 structural elements of the formula (2.2) and traces of the structural element of the formula -S0 3 Na .

Vorschrift C: Man verfährt wie in Vorschrift A angegeben, setzt jedoch eine Lösung aus 185 Teilen Acrylsäure (2,56 Mol), 34 Teilen Acrylnitril (0,64 Mol) und 55,6 Teilen der Natriumhydrogensulfit-Lösung (0,214 Mol) in 257 Teilen Wasser ein, die mit insgesamt 10,7 Teilen der Ammoniumperoxodisulfat-Lösung in 10 Portionen und, nach der Verdünnung mit 116,4 Teilen Wasser, mit 341,3 Teilen der Natriumhydroxyd- Lösung (2,56 Mol) versetzt wird. Man erhält 1000 Teile einer hellgelben, gelartigen, klaren, wässrigen Lösung, die 28% eines Oligomers enthält, das etwa 3 Strukturelemente der Formel (1.4), etwa 12 Strukturelemente der Formel (2.2) und Spuren des Strukturelementes der Formel -SO3Na aufweist.Instructions C: The procedure described in Instructions A is followed, but a solution of 185 parts of acrylic acid (2.56 mol), 34 parts of acrylonitrile (0.64 mol) and 55.6 parts of the sodium bisulfite solution (0.214 mol) is used in 257 Parts of water, which are mixed with a total of 10.7 parts of the ammonium peroxodisulfate solution in 10 portions and, after dilution with 116.4 parts of water, with 341.3 parts of the sodium hydroxide solution (2.56 mol). This gives 1000 parts of a light yellow, gel-like, clear, aqueous solution which contains 28% of an oligomer which has about 3 structural elements of the formula (1.4), about 12 structural elements of the formula (2.2) and traces of the structural element of the formula -SO 3 Na .

Verfahren D: Man verfährt wie in Vorschrift A angegeben, setzt jedoch eine Lösung aus 138,3 Teilen Acrylsäure (1,92 Mol), 127,3 Teilen Acrylnitril (2,4 Mol), 34,1 Teilen Acrylamid (0,48 Mol) und 41,6 Teilen der Natriumhydrogensulfit-Lösung (0,16 Mol) in 298,4 Teilen Wasser ein, die mit insgesamt 11,4 Teilen der Ammoniumperoxodisulfat-Lösung in 10 Portionen und, nach der Verdünnung mit 92,9 Teilen Wasser, mit 256 Teilen der Natriumhydroxyd-Lösung (1,92 Mol) versetzt wird. Man erhält 1000 Teile einer hellgelben, gelartigen, klären, wässrigen Lösung, die 34% eines Oligomers enthält, das etwa 3 Strukturelemente der Formel (3.2), etwa 15 Strukturelemente der Formel (1.4), etwa 12 Strukturelemente der Formel (2.2) und Spuren des Strukturelementes der Formel -S03Na aufweist.Process D: The procedure is as described in instruction A, but a solution of 138.3 parts of acrylic acid (1.92 mol), 127.3 parts of acrylonitrile (2.4 mol), 34.1 parts of acrylamide (0.48 mol ) and 41.6 parts of the sodium bisulfite solution (0.16 mol) in 298.4 parts of water, which together with a total of 11.4 parts of the ammonium peroxodisulfate solution in 10 portions and, after dilution with 92.9 parts of water, 256 parts of the sodium hydroxide solution (1.92 mol) are added. 1000 parts of a light yellow, gel-like, clear, aqueous solution which contains 34% of an oligomer which contains about 3 structural elements of the formula (3.2), about 15 structural elements of the formula (1.4), about 12 structural elements of the formula (2.2) and traces are obtained of the structural element of the formula -S0 3 Na.

Vorschrift E: Man verfährt wie in Vorschrift A angegeben, setzt jedoch eine Emulsion aus 211 Teilen Acrylsäure (2,92 Mol), 141,5 Teilen 'Vinylacetat (1,64 Mol) und 43 Teilen der 40%-igen Natriumhydrogensulfitlösung (0,165 Mol) in 80 ml Wasser ein, die bei 50°C mit insgesamt 1,5 Teilen Ammoniumperoxodisulfat in 25 ml Wasser gelöst in 10 Portionen und,nach der Verdünnung mit 155 Teilen Wasser,mit 320 Teilen der Natriumhydroxydlösung .(2,4 Mol) versetzt wird. Man erhält 1000 Teile einer hellgelben, gelartigen wässrigen Lösung,, die 40% eines Oligomers enthält, das etwa 10 Strukturelemente der Formel (1.3), worin X4 -COOCH3 und Z4 Wasserstoff bedeuten, etwa 18 Strukturelemente der Formel (2.2) und ,Spuren des Strukturelementes der Formel -SO3Na aufweist.Instructions E: The procedure described in Instructions A is followed, but an emulsion of 211 parts of acrylic acid (2.92 mol), 141.5 parts of vinyl acetate (1.64 mol) and 43 parts of the 40% sodium bisulfite solution (0.165 mol ) in 80 ml of water, which, at 50 ° C., contains a total of 1.5 parts of ammonium peroxodisulfate in 25 ml of water in 10 portions and, after dilution with 155 parts of water, 320 parts of the sodium hydroxide solution (2.4 mol) becomes. 1000 parts of a light yellow, gel-like aqueous solution are obtained, which contains 40% of an oligomer which contains about 10 structural elements of the formula (1.3), in which X 4 is -COOCH 3 and Z 4 are hydrogen, about 18 structural elements of the formula (2.2) and , Traces of the structural element of the formula -SO 3 Na.

Vorschrift F: 171 Teile Wasser, zuerst 74,9 Teile Acrylnitril (1,41 Mol), dann 101,7 Teile Acrylsäure (1,41 Mol) und schliesslich 24,3 Teile einer 40%igen, wässrigen Natriumhydrogensulfit-Lösung (0,93 Mol) werden vorgelegt. Nun wird eine Lösung von 0,6 Teilen Ammoniumperoxodisulfat in 6 Teilen Wasser innerhalb von 5 bis 8 Stunden zum Reaktionsgemisch so zudosiert, dass die Temperatur nicht über 45°C steigt. Nach beendeter Katalysatorzugabe werden 60 Teile Wasser zu-' gegeben und das Reaktionsgemisch während 5 Stunden bei 75°C gehalten.Regulation F: 171 parts of water, first 74.9 parts of acrylonitrile (1.41 mol), then 101.7 parts of acrylic acid (1.41 mol) and finally 24.3 parts of a 40% aqueous sodium hydrogen sulfite solution (0.0 93 mol) are presented. A solution of 0.6 parts of ammonium peroxodisulfate in 6 parts of water is then metered into the reaction mixture in the course of 5 to 8 hours in such a way that the temperature does not rise above 45 ° C. After the catalyst addition has ended, 60 parts of water are added and the reaction mixture is kept at 75 ° C. for 5 hours.

Anschliessend werden dem Reaktionsgemisch 146 Teile einer 30%igen, wässrigen Natriumhydroxydlösung innerhalb von etwa 1,5 Stunden so zugegeben, dass die Temperatur nicht über 50°C steigt. Nun wird das Reaktionsgemisch auf Rückflusstemperatur (98-100°C) geheizt und unter einem vermindertem Druck von -0,8 bis -1,0 bar während etwa 8 Stunden auf Rückflusstemperatur gehalten, bis eine Probe des Reaktionsgemisches weniger als 100 ppm unumgesetztes Acrylnitril aufweist. Anschliessend wird das Reaktionsgemisch auf 20°C abgekühlt und durch portionsweise Zugabe von insgesamt ca. 22 Teilen einer 30%igen, wässrigen Natriumhydroxydlösung auf den pH-Wert von 6,1 bis 6,3 gestellt. Man erhält ca. 600 Teile einer klaren, leicht gelblichen Lösung, die 33 bis 34% eines Oligomers enthält, das je 25 bis 30 Strukturelemente der Formeln (1.4) und (2.2).aufweist.146 parts of a 30% strength aqueous sodium hydroxide solution are then added to the reaction mixture over the course of about 1.5 hours in such a way that the temperature does not rise above 50.degree. Now the reaction mixture is heated to reflux temperature (98-100 ° C.) and kept under a reduced pressure of -0.8 to -1.0 bar for about 8 hours at reflux temperature until a sample of the reaction mixture has less than 100 ppm unconverted acrylonitrile . The reaction mixture is then cooled to 20 ° C. and adjusted to a pH of 6.1 to 6.3 by adding a total of about 22 parts of a 30% strength aqueous sodium hydroxide solution in portions. About 600 parts of a clear, slightly yellowish solution are obtained which contains 33 to 34% of an oligomer which has 25 to 30 structural elements of the formulas (1.4) and (2.2).

Vorschrift G: Man verfährt wie in Vorschrift A angegeben, setzt jedoch eine Lösung aus 128,4 Teilen Acrylsäure (1,78 Mol), 144,2 Teilen Methacrylsäurehydroxypropylester (1 Mol) und 47,4 Teilen einer 25 %igen, wässrigen Kaliumhydrogensulfit-Lösung (0,1 Mol) in 100 Teilen Wasser ein, die mit insgesamt 10 Teilen der Ammoniumperoxodisulfat-Lösung in 10 Portionen bei 60°C und, nach der Verdünnung mit 351,5 Teilen Wasser, mit 218,5 Teilen der Natriumhydroxyd-Lösung (1,63 Mol) versetzt wird. Man erhält 1000 Teile einer leicht gelblichen, gelartigen, klaren, wässrigen Lösung, die 31 % eines Oligomers enthält, das etwa 12 Strukturelemente der Formel (1.3), worin X4 -COOC3H6OH und Z4 Methyl bedeuten, etwa 22 Strukturelemente der Formel (2.2) und Spuren des Strukturelementes der Formel -S03Na aufweist.Instructions G: The procedure described in Instructions A is followed, but a solution of 128.4 parts of acrylic acid (1.78 mol), 144.2 parts of methacrylic acid hydroxypropyl ester (1 mol) and 47.4 parts of a 25% strength aqueous potassium hydrogen sulfite solution is used. Solution (0.1 mol) in 100 parts of water with a total of 10 parts of the ammonium peroxodisulfate solution in 10 portions at 60 ° C and, after dilution with 351.5 parts of water, with 218.5 parts of the sodium hydroxide solution (1.63 mol) is added. This gives 1000 parts of a slightly yellowish, gel-like, clear, aqueous solution which contains 31% of an oligomer which has about 12 structural elements of the formula (1.3) in which X 4 is -COOC 3 H 6 OH and Z 4 is methyl, about 22 structural elements of the formula (2.2) and traces of the structural element of the formula -S0 3 Na.

Vorschrift H: Man verfährt wie in Vorschrift A angegeben, setzt jedoch eine Lösung aus 73,6 Teilen Acrylsäure-2-äthoxyäthylester (0,51 Mol), 93,8 Teilen Acrylsäure (1,30 Mol) und 33,6 Teilen einer 25 %igen, wässrigen Kaliumhydrogensulfit-Lösung (0,07 Mol) in 60 Teilen Wasser ein, die mit insgesamt 5 Teilen der Ammoniumperoxodisulfat-Lösung in 5 Portionen bei 60°C und, nach der Verdünnung mit 565,8 Teilen Wasser, mit 168,2 Teilen der Natriumhydroxyd-Lösung (1,26 Mol) versetzt wird. Man erhält 1000 Teile einer klaren, wässrigen Lösung, die 20 % eines Oligomers enthält, das etwa 7,3 Strukturelemente der Formel (1), worin X1-COOR1, R1 2-Aethoxyäthyl und Z1 Wasserstoff bedeuten, etwa 18,5 Strukturelemente der Formel (2.2) und Spuren des Strukturelementes der Formel -S03Na aufweist.Instructions H: The procedure described in Instructions A is followed, but a solution of 73.6 parts of 2-ethoxyacrylic acid (0.51 mol), 93.8 parts of acrylic acid (1.30 mol) and 33.6 parts of a 25 %, aqueous potassium hydrogen sulfite solution (0.07 mol) in 60 parts of water, which with a total of 5 parts of the ammonium peroxodisulfate solution in 5 portions at 60 ° C and, after dilution with 565.8 parts of water, with 168, 2 parts of the sodium hydroxide solution (1.26 mol) is added. This gives 1000 parts of a clear, aqueous solution which contains 20% of an oligomer which has about 7.3 structural elements of the formula (1) in which X 1 is -COOR 1 , R 1 2-ethoxyethyl and Z 1 is hydrogen, about 18, Has 5 structural elements of the formula (2.2) and traces of the structural element of the formula -S0 3 Na.

Vorschrift I: Man verfährt wie in Vorschrift A angegeben, setzt jedoch eine Lösung aus 130,7 Teilen Acrylsäure (1,81 Mol), 120,3 Teilen Acrylnitril (2,26 Mol), 26,3 Teilen Allylalkohol (0,40 Mol) und 72,6 Teilen einer 25 %igen, wässrigen Kaliumhydrogensulfit-Lösung (0,15 Mol) in 283,5 Teilen Wasserein, die mit insgesamt 37,8 Teilen einer Ammoniumperoxodisulfat-Lösung in 5 Portionen und, nach der Verdünnung mit 87 Teilen Wasser, mit 241,8 Teilen der Natriumhydroxyd-Lösung (1,81 Mol) versetzt wird. Man erhält 1000 Teile einer hellgelben, gelartigen, klaren, wässrigen Lösung, die 32 % eines Oligomers enthält, das etwa 2,6 Strukturelemente der Formel (3.1), worin Y4 -CH20H und Z6 Wasserstoff sind, etwa 15 Strukturelemente der Formel (1.4); etwa 12 Strukturelemente der Formel (2.2), und Spuren des Strukturelementes der Formel -S03Na aufweist.Instructions I: The procedure described in Instructions A is followed, but a solution of 130.7 parts of acrylic acid (1.81 mol), 120.3 parts of acrylonitrile (2.26 mol), 26.3 parts of allyl alcohol (0.40 mol ) and 72.6 parts of a 25% aqueous potassium hydrogen sulfite solution (0.15 mol) in 283.5 parts of water, which together with 37.8 parts of an ammonium peroxodisulfate solution in 5 portions and, after dilution with 87 parts Water, with 241.8 parts of the sodium hydroxide solution (1.81 mol) is added. 1000 parts of a light yellow, gel-like, clear, aqueous solution which contains 32% of an oligomer which contains about 2.6 structural elements of the formula (3.1), in which Y 4 -CH 2 OH and Z 6 are hydrogen, about 15 structural elements of the Formula (1.4); about 12 structural elements of the formula (2.2), and traces of the structural element of the formula -S0 3 Na.

Vorschrift J: Man verfährt wie in Vorschrift A angegeben, setzt jedoch eine Lösung aus 133 Teilen Acrylsäure (1,84 Mol) 149,4 Teilen Methylacrylsäurehydroxypropylester (1,03 Mol) und 49 Teilen einer 25 %igen, wässrigen Kaliumhydrogensulfit-Lösung (0,10 Mol) in 98,4 Teilen Wasser ein, die mit insgesamt 12,2 Teilen der Ammoniumperoxodisulfat-Lösung in 10 Portionen bei 40°C und, nach der Verdünnung mit 461,7 Teilen Wasser, mit 96,3 Teilen einer 30 %igen, wässrigen Ammoniak-Lösung (1,7 Mol) versetzt wird. Man erhält 1000 Teile einer gelblichen, gelartigen, klaren, wässrigen Lösung, die 31 % eines Oligomers enthält, das etwa 10 Strukturelemente der Formel (1.3), worin X4 -COOC3H60H und Z4 Methyl bedeuten, etwa 18 Strukturelemente der Formel (2.1), worin Z5 Wasserstoff, Y3 -COOM4 und M4 ein Ammoniumkation bedeuten und Spuren des Strukturelementes der Formel -S03NH4 aufweist.Instructions J: The procedure described in Instructions A is followed, but a solution of 133 parts of acrylic acid (1.84 mol), 149.4 parts of methyl acrylate hydroxypropyl ester (1.03 mol) and 49 parts of a 25% strength aqueous potassium hydrogen sulfite solution (0 , 10 mol) in 98.4 parts of water, which with a total of 12.2 parts of the ammonium peroxodisulfate solution in 10 portions at 40 ° C. and, after dilution with 461.7 parts of water, with 96.3 parts of a 30% aqueous ammonia solution (1.7 mol) is added. This gives 1000 parts of a yellowish, gel-like, clear, aqueous solution which contains 31% of an oligomer which has about 10 structural elements of the formula (1.3) in which X 4 is -COOC 3 H 6 0H and Z 4 is methyl, about 18 structural elements of the Formula (2.1), wherein Z 5 is hydrogen, Y 3 -COOM 4 and M 4 are an ammonium cation and has traces of the structural element of the formula -S0 3 NH 4 .

Beispiel 1: 100 Teile eines auf übliche Art und Weise neutralisierten chromgegerbten Kalbsleders werden mit einer Lösung aus 200 Teilen Wasser und 5 Teilen, berechnet auf Trockensubstanz, des Oligomers gemäss Vorschrift A während 1 1/2 Stunden bei 30°C nachbehandelt. Nach kurzem Spülen wird das nachbehandelte Leder wie üblich mit 4 bis 6 Teilen eines lichtechten Fettungsmittels auf der Basis von sulfoniertem Spermöl gefettet und anschliessend getrocknet.Example 1: 100 parts of a chrome-tanned calfskin neutralized in a conventional manner are aftertreated with a solution of 200 parts of water and 5 parts, calculated on dry substance, of the oligomer according to specification A for 1 1/2 hours at 30 ° C. After a short rinse, the aftertreated leather is greased as usual with 4 to 6 parts of a lightfast fatliquor based on sulfonated sperm oil and then dried.

Man erhält ein Leder von heller Farbe, ausgezeichneter Lichtechtheit, mit einem weichen vollen Griff und mit einem feinen Narbenbild. Dies trifft auch zu beim Ersatz von 5 Teilen des Oligomers gemäss. Vorschrift A durch 5 Teile des Oligomers gemäss Vorschrift F.A leather of light color, excellent lightfastness, with a soft full grip and with a fine grain is obtained. This also applies to the replacement of 5 parts of the oligomer according to. Regulation A by 5 parts of the oligomer according to Regulation F.

Beispiel 2: 100 Teile chromgegerbtes Schafsleder werden mit 200 Teilen Wasser von 40°C versetzt. Hierauf werden zur Flotte 10 Teile, berechnet auf Trockensubstanz, eines Oligomers gemäss Vorschrift B hinzugefügt und während.2 Stunden bei 40°C auf das Leder einwirken gelassen. Nach dem Spülen wird das behandelte Leder mit ca. 5 Teilen eines üblichen Fettungsmittels gefettet und anschliessend getrocknet. Man erhält ein volles, geschmeidiges Leder mit einem geschlossenen, fest haftendem Narben. Dies trifft auch zu beim Ersatz von -10 Teilen des Oligomers gemäss Vorschrift B durch 10 Teile des Oligomers gemäss Vorschrift C.Example 2: 100 parts of chrome-tanned sheep leather are mixed with 200 parts of water at 40 ° C. Then 10 parts, calculated on dry substance, of an oligomer according to regulation B are added to the liquor and left to act on the leather for 2 hours at 40 ° C. After rinsing, the treated leather is greased with about 5 parts of a conventional fatliquor and then dried. You get a full, supple leather with a closed, firmly adhering scars. This also applies to the replacement of -10 parts of the oligomer according to regulation B by 10 parts of the oligomer according to regulation C.

Beispiel 3: 100 g chromgares, gefalztes Rindsleder wird im Fass in 200 Teilen Flotte auf bekannte Weise soweit neutralisiert, dass der pH-Wert des Leders im Schnitt unter 4 bleibt. Anschliessend wird das Bad mit 6 Teilen, berechnet auf Trockensubstanz, desTerpolymers gemäss Vorschrift D versetzt und das neutralisierte Leder während 2 Stunden bei 45°C behandelt. In frischer Flotte (300 Teile), enthaltend 1 Teil Farbstoff der Formel

Figure imgb0013
wird das Leder bei 60°C während 30 Minuten gefärbt. Nach dem Absäuern mit 1 Teil 85Ziger Ameisensäure während 30 Minuten bei 50°C werden in das ausgezogene Färbebad 3 Teile sulfatiertes Klauenöl gegeben und das Rindsleder während 60 Minuten bei 60°C gefettet. Das Leder wird nun ausgereckt und getrocknet. Nach dem Stollen erhält man ein Leder von guter Fülle mit weichem Griff, kompaktem, feinem Narben und egaler, intensiver brauner Färbung. Dies trifft auch zu beim Ersatz von 6 Teilen des Terpolymers gemäss Vorschrift D durch 6 Teile des Terpolymers gemäss Vorschrift E, durch 6 Teile des Copolymers gemäss Vorschrift G, durch 6 Teile des Copolymers gemäss Vorschrift H, durch 6 Teile des Terpolymers gemäss Vorschrift I oder durch 6 Teile des Copolymers gemäss Vorschrift J.Example 3: 100 g of chrome-cooked, folded cowhide leather is neutralized in a barrel in 200 parts of liquor in a known manner to such an extent that the pH of the leather remains below 4 on average. The bath is then mixed with 6 parts, calculated on dry substance, of the terpolymer according to regulation D and the neutralized leather is treated at 45 ° C for 2 hours. In a fresh liquor (300 parts) containing 1 part of the dye of the formula
Figure imgb0013
 the leather is dyed at 60 ° C for 30 minutes. After acidifying with 1 part of 85% formic acid for 30 minutes at 50 ° C, 3 parts of sulfated claw oil are added to the dyed bath and the cowhide is greased at 60 ° C for 60 minutes. The leather is now stretched out and dried. After the tunnel, you get a leather of good fullness with a soft feel, compact, fine scars and level, intense brown color. This also applies to the replacement of 6 parts of the terpolymer according to regulation D by 6 parts of the terpolymer according to regulation E, by 6 parts of the copolymer according to regulation G, by 6 parts of the copolymer according to regulation H, by 6 parts of the terpolymer according to regulation I or by 6 parts of the copolymer according to regulation J.

Claims (10)

1. Verfahren zum Nachgerben von chromgegerbtem, gegebenenfalls gefärbtem Leder, dadurch gekennzeichnet, dass man das Leder mit einer wässrigen Lösung behandelt, die als Gerbstoff ein Oligomer enthält, welches Strukturelemente der Formeln
Figure imgb0014
aufweist, worin X1 -CN, -COOR1, -OOCR2 oder -CONHR3, Y1 -COOH oder -COOM2, Y2 -CONH2, -CH2OH, -OCH3 oder -OC2H5, Z1, Z2 und Z3 je Wasserstoff, Methyl oder Aethyl, M1 und M2 je ein Amin-, Ammonium- oder Alkalimetall-Kation und R1, R2 und R3 je Alkyl, Hydroxyalkyl oder Alkoxyalkyl mit insgesamt höchstens 8 Kohlenstoffatomen bedeuten, und das behandelte Leder fettet und trocknet, wobei vor oder nach dem Fetten das behandelte Leder gegebenenfalls noch gefärbt wird.1. A process for retanning chrome-tanned, optionally dyed leather, characterized in that the leather is treated with an aqueous solution which contains an oligomer as the tanning agent, which structural elements of the formulas
Figure imgb0014
 in which X 1 is -CN, -COOR 1 , -OOCR 2 or -CONHR 3 , Y 1 -COOH or -COOM 2 , Y 2 -CONH 2 , -CH 2 OH, -OCH 3 or -OC 2 H 5 , Z 1 , Z 2 and Z 3 each hydrogen, methyl or ethyl, M 1 and M 2 each an amine, ammonium or alkali metal cation and R 1 , R 2 and R 3 each alkyl, hydroxyalkyl or alkoxyalkyl with a total of at most 8 Are carbon atoms, and the treated leather greases and dries, the treated leather possibly being dyed before or after the greasing. . 2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass man als Gerbstoff ein Oligomer einsetzt, dessen durchschnittliches Molekulargewicht höchstens 14'000 beträgt.. 2. The method according to claim 1, characterized in that the tanning agent used is an oligomer whose average molecular weight is at most 14,000. 3. Verfahren nach einem der Ansprüche 1 oder 2, dadurch gekennzeichnet, dass man als Gerbstoff ein Oligomer einsetzt, welches je 2 bis 75 Strukturelemente der Formeln
Figure imgb0015
und 0 bis 25 Strukturelemente der Formel
Figure imgb0016
aufweist, worin M1, X 1, Y1, Y2, Z1, Z2 und Z3 je die in Anspruch 1 angegebenen Bedeutungen haben.3. The method according to any one of claims 1 or 2, characterized in that an oligomer is used as the tanning agent, each having 2 to 75 structural elements of the formulas
Figure imgb0015
 and 0 to 25 structural elements of the formula
Figure imgb0016
 in which M 1 , X 1 , Y 1 , Y 2 , Z 1 , Z 2 and Z 3 each have the meanings given in Claim 1. 4. Verfahren nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass man als Gerbstoff ein Oligomer einsetzt, welches Strukturelemente der Formeln
Figure imgb0017
und gegebenenfalls
Figure imgb0018
aufweist, worin X2 -CN, -COOR4, -OOCR5 oder -CONHR6, R4 Alkyl, Hydroxyalkyl oder Methoxyalkyl mit insgesamt höchstens 4 Kohlenstoffatomen, R5 Methyl oder Aethyl und R6 Alkyl mit 1 bis 8 Kohlenstoffatomen oder Hydroxyalkyl mit 1 oder 2 Kohlenstoffatomen bedeuten und M1, Y1, Y2, Z 1, Z2 und Z3 je die in Anspruch 1 angegebenen Bedeutungen haben.4. The method according to any one of claims 1 to 3, characterized in that an oligomer is used as the tanning agent, which structural elements of the formulas
Figure imgb0017
 and if necessary
Figure imgb0018
 , wherein X 2 -CN, -COOR 4 , -OOCR 5 or -CONHR 6 , R 4 alkyl, hydroxyalkyl or methoxyalkyl with a total of at most 4 carbon atoms, R 5 methyl or ethyl and R 6 alkyl having 1 to 8 carbon atoms or hydroxyalkyl 1 or 2 carbon atoms and M 1 , Y 1 , Y 2 , Z 1 , Z 2 and Z 3 each have the meanings given in claim 1. 5. Verfahren nach Anspruch 4, dadurch gekennzeichnet ,dass man als Gerbstoff ein Oligomer einsetzt, welches Strukturelemente der Formeln
Figure imgb0019
und gegebenenfalls
Figure imgb0020
aufweist, worin X3 -CN, -COOCH3, -COOC2H5, -COOC2H4OH, -COOC3H6OH, -COOC2H4OCH3, -OOCCH3, -OOCC2H5, -CONHCH3, -CONHC2H5, -CONHCH2OH, -CONHC3H7 oder -CONHC8H17 bedeutet und M1, Y1, Y2, Z1, Z2 und Z3 je die in Anspruch 1 angegebenen Bedeutungen haben.5. The method according to claim 4, characterized in that an oligomer is used as tanning agent, which structural elements of the formulas
Figure imgb0019
 and if necessary
Figure imgb0020
 in which X 3 is -CN, -COOCH 3 , -COOC 2 H 5 , -COOC 2 H 4 OH, -COOC 3 H 6 OH, -COOC 2 H 4 OCH 3 , -OOCCH 3 , -OOCC 2 H 5 , -CONHCH 3, -CONHC 2 H 5, -CONHCH 2 OH, -CONHC 3 H 7 or -CONHC 8 H 17, and M 1, Y 1, Y 2, Z 1, Z 2 and Z 3 j e in the claim 1 have the meanings given. 6. Verfahren nach Anspruch 5, dadurch gekennzeichnet, dass man als Gerbstoff ein Oligomer einsetzt, welches Strukturelemente der Formeln
Figure imgb0021
und gegebenenfalls
Figure imgb0022
aufweist, worin X4 -CN, -COOCH3, -COOC2H5, -COOC2H4OH, -COOC3H6OH, -OOCCH3, -OOCC2H5, -CONHCH3, -CONHC2H5, -CONHC3H7 und -CONHC8H17, Y3 -COOH oder -COOM4, Y4 -CONH2, -CH2OH oder -OCH3, M und M4 je ein Natrium-, Kalium- oder Ammoniumkation und Z4, Z5 und Z6 je Wasserstoff oder Methyl bedeuten.6. The method according to claim 5, characterized in that an oligomer is used as tanning agent, which structural elements of the formulas
Figure imgb0021
 and if necessary
Figure imgb0022
 wherein X 4 is -CN, -COOCH 3 , -COOC 2 H 5 , -COOC 2 H 4 OH, -COOC 3 H 6 OH, -OOCCH 3 , -OOCC 2 H 5 , -CONHCH 3 , -CONHC 2 H 5 , -CONHC 3 H 7 and -CONHC 8 H 17 , Y 3 -COOH or -COOM 4 , Y 4 -CONH 2 , -CH 2 OH or -OCH 3 , M and M 4 each a sodium, potassium or Ammonium cation and Z 4 , Z5 and Z 6 each represent hydrogen or methyl. 7. Verfahren nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, dass man auf 100 Gewichtsteile Leder 2 bis 50 Gewichtsteile, bezogen auf Trockensubstanz, des Oligomers als Gerbstoff einsetzt.7. The method according to any one of claims 1 to 6, characterized in that 2 to 50 parts by weight, based on dry substance, of the oligomer is used as tanning agent per 100 parts by weight of leather. 8. Verfahren nach einem der Ansprüche 1 bis 7, dadurch gekennzeichnet, dass man das Leder mit der wässrigen Lösung, die das Oligomer als Gerbstoff enthält, während 1 bis 4 Stunden bei 10 bis 50°C behandelt und das so behandelte Leder entweder spült, fettet und trocknet oder färbt, fettet und trocknet.8. The method according to any one of claims 1 to 7, characterized in that the leather is treated with the aqueous solution containing the oligomer as a tanning agent for 1 to 4 hours at 10 to 50 ° C and the leather thus treated is either rinsed, greases and dries or stains, greases and dries. 9. Wässrige Lösung zur Durchführung des Verfahrens gemäss einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, dass sie 1 bis 10 Gewichtsprozent Oligomer als Gerbstoff enthält.9. Aqueous solution for carrying out the method according to one of claims 1 to 8, characterized in that it contains 1 to 10 percent by weight of oligomer as a tanning agent. 10. Verwendung des Oligomers, das Strukturelemente der in Anspruch 1 angegebenen Formeln aufweist, als Gerbstoff zum Nachgerben von chromgegerbtem, gegebenenfalls gefärbtem Leder.10. Use of the oligomer, which has structural elements of the formulas specified in claim 1, as a tanning agent for retanning chrome-tanned, optionally dyed leather.
EP82810091A 1981-03-06 1982-03-01 Method of retanning leather with acrylic oligomers Expired - Lifetime EP0061420B2 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
CH1528/81 1981-03-06
CH152881A CH646731A5 (en) 1981-03-06 1981-03-06 Process for retanning chrome-tanned leather with sulphite-containing acrylic oligomers
CH8201/81 1981-12-22
CH820181 1981-12-22

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EP0061420A1 true EP0061420A1 (en) 1982-09-29
EP0061420B1 EP0061420B1 (en) 1985-10-30
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AR (1) AR243557A1 (en)
CA (1) CA1192703A (en)
DE (1) DE3267088D1 (en)
ES (1) ES8302784A1 (en)

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US4526581A (en) * 1983-02-07 1985-07-02 Rohm And Haas Company Process for producing leather
EP0163057A1 (en) * 1984-04-09 1985-12-04 Chemische Fabrik Stockhausen GmbH Process for retanning mineral or combined tanned leather with polymeric tanning agents
US4596581A (en) * 1982-01-16 1986-06-24 Basf Aktiengesellschaft Carboxyl- and amino-containing copolymer for after-tanning mineral tanned leather
FR2701716A1 (en) * 1993-02-18 1994-08-26 Sandoz Ag Leather retannage process
CN104313204A (en) * 2014-10-27 2015-01-28 浙江理工大学 Preparation method of greasing agent for hardened leather cultural relics through ultrasonic technology
CN104328229A (en) * 2014-10-27 2015-02-04 浙江理工大学 Preparation method of soybean oil greasing agent for leather cultural relics

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US5348807A (en) * 1991-02-05 1994-09-20 Rohm And Haas Company Polymeric retan fatliquor for low fogging upholstery leather
DE4227974C2 (en) * 1992-08-26 1996-04-18 Stockhausen Chem Fab Gmbh Copolymers containing alkoxy groups, processes for their preparation and their use for retanning leather
DE4242076A1 (en) * 1992-12-14 1994-06-16 Roehm Gmbh Tanning agent contg. omega,omega'-di-aldehyde - and polymer contg. hydroxy gps., giving uniform distribution of chrome in chrome tanning, level dyeing and easy paring
US5428117A (en) * 1993-10-18 1995-06-27 Interface, Inc. Treatment for imparting stain resistance to polyamide substrates and resulting stain resistant materials
US5820633A (en) * 1996-09-20 1998-10-13 Lesko; Patricia Marie Method of treating leather with improved retaining agents
EP3257955B1 (en) 2016-06-13 2022-09-07 TFL Ledertechnik GmbH Process for pretanning or retanning leather using carboxymethylcellulose and its salts

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Cited By (8)

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US4596581A (en) * 1982-01-16 1986-06-24 Basf Aktiengesellschaft Carboxyl- and amino-containing copolymer for after-tanning mineral tanned leather
US4526581A (en) * 1983-02-07 1985-07-02 Rohm And Haas Company Process for producing leather
EP0163057A1 (en) * 1984-04-09 1985-12-04 Chemische Fabrik Stockhausen GmbH Process for retanning mineral or combined tanned leather with polymeric tanning agents
FR2701716A1 (en) * 1993-02-18 1994-08-26 Sandoz Ag Leather retannage process
ES2097695A1 (en) * 1993-02-18 1997-04-01 Sandoz Ag Re-tanning process
CN104313204A (en) * 2014-10-27 2015-01-28 浙江理工大学 Preparation method of greasing agent for hardened leather cultural relics through ultrasonic technology
CN104328229A (en) * 2014-10-27 2015-02-04 浙江理工大学 Preparation method of soybean oil greasing agent for leather cultural relics
CN104328229B (en) * 2014-10-27 2016-09-14 浙江理工大学 A kind of preparation method for cortex historical relic soybean oil fatting agent

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EP0061420B2 (en) 1992-01-29
AR243557A1 (en) 1993-08-31
US4439201A (en) 1984-03-27
ES510160A0 (en) 1983-02-01
DE3267088D1 (en) 1985-12-05
EP0061420B1 (en) 1985-10-30
ES8302784A1 (en) 1983-02-01
CA1192703A (en) 1985-09-03

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