EP0127055B1 - Method of finishing leather with a synthetic carboxylated rubber latex - Google Patents

Method of finishing leather with a synthetic carboxylated rubber latex Download PDF

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Publication number
EP0127055B1
EP0127055B1 EP19840105470 EP84105470A EP0127055B1 EP 0127055 B1 EP0127055 B1 EP 0127055B1 EP 19840105470 EP19840105470 EP 19840105470 EP 84105470 A EP84105470 A EP 84105470A EP 0127055 B1 EP0127055 B1 EP 0127055B1
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Prior art keywords
parts
weight
monomers
leather
carboxylated rubber
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EP19840105470
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German (de)
French (fr)
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EP0127055A1 (en
Inventor
Guenter Dr. Eckert
Wolfgang Dr. Groh
Hans Dr. Luetje
Franz Dr. Schmidt
Juergen Dr. Schmidt-Thuemmes
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BASF SE
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BASF SE
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    • 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
    • C14C11/00—Surface finishing of leather
    • C14C11/003—Surface finishing of leather using macromolecular compounds
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/4935—Impregnated naturally solid product [e.g., leather, stone, etc.]

Definitions

  • the present invention relates to a process for finishing leather with a carboxylated rubber dispersion based on butadiene and / or isoprene and styrene and optionally oxides and / or hydroxides of 2 and / or 3-valent metals.
  • Aqueous polyacrylate dispersions aqueous dispersions of vinyl acetate copolymers or aqueous dispersions of synthetic rubbers, ie. H. Copolymers of 1,3-dienes, such as butadiene, isoprene or chloroprene, are used.
  • the suitable pigments can be organic or inorganic in nature; come into question z.
  • such dressings can include thickeners, e.g. B. based on cellulose, such as carboxymethyl cellulose, polyvinyl alcohols, polyacrylic acid or their salts, casein or polymers of N-vinylpyrrolidone.
  • binders of the type mentioned are satisfactory when dressing split leather, e.g. B. for upper leather, not yet, as they show poor embossability, poor cold flexibility and insufficient dry and wet buckling strength.
  • Aqueous dispersions of synthetic rubber dispersions containing carboxyl groups have also been used as binders in the finishing of leather.
  • a dressing with improved hot ironing strength is achieved with the addition of zinc compounds, but with which the gloss, fullness and coverage as well as the grip are deteriorated and when different layers are applied due to insufficient adhesion of the layers to one another there is poor wet kink resistance .
  • the dressings known from GB-PS 921 798 and 900591 based on rubber dispersions containing polymerized carboxyl groups are also unsatisfactory in terms of their resistance to dry kinking.
  • EP-A-0 029 170 discloses a process for finishing leather, in which a carboxylated synthetic rubber latex is used which is not completely polymerized and in which the remaining monomers have been removed.
  • the rubber is mixed with the batch-Wd / HB procedure (one-stage process) by emulsion polymerization of 1 to 10 parts by weight of a, ⁇ -monoethylenically unsaturated aliphatic carboxylic acids and 90 to 99 parts by weight of a mixture of acyclic, conjugated dienes 4 to 9 carbon atoms and of vinyl aromatics with 8 to 12 carbon atoms and / or (meth) acrylonitrile with a (meth) acrylonitrile content of at most 50 parts by weight.
  • the dressing agent contains 0.5 to 50% by weight, based on the rubber, of one or more oxides and / or hydroxides of divalent metals such as zinc oxide or magnesium hydroxide.
  • Preparations of split leather, which are produced by this process, show good closure and coverage, grain throw, toughness, flexibility at low temperatures and adhesion as well as dry and wet buckling strengths, but their embossability and stack stickiness still leave something to be desired.
  • the aqueous dispersions of the synthetic carboxylated rubber dispersions used for the dressings generally have a carboxylated rubber concentration of 30 to 60, in particular from 35 to 55% by weight.
  • part of the monomer mixture in emulsified form together with a corresponding part of the emulsifier and the polymerization initiator as well as a regulator are introduced in an aqueous receiver, the receiver is heated to the polymerization temperature and, after the polymerization has started, the remaining monomer emulsion, which contains the emulsifier and generally regulator, and separately run an aqueous solution of the polymerization initiator according to consumption.
  • the mixture is then generally allowed to react further, so that the conversion is over 90, mostly 95 to 98%.
  • the polymerization temperature is usually selected in the range from 45 to 65 ° C. and generally customary water-soluble radical-forming polymerization initiators such as sodium and ammonium persulfate or redox catalysts such as tert-butyl perbenzoate / formaldehyde sulfoxylate / iron (11) sulfate and tert.- Butyl hydroperoxide / ascorbic acid / iron (II) sulfate used. Water-soluble persulfates of the type mentioned are preferred.
  • anionic and nonionic emulsifiers are suitable as emulsifiers, anionic emulsifiers being of particular interest.
  • Sodium lauryl sulfate or alkylarylsulfonates with mostly 7 to 12 carbon atoms in the alkyl groups are preferably used as emulsifiers.
  • the aqueous carboxylated rubber dispersions contain 1 to 10, preferably 1 to 5 parts by weight of a, ⁇ -monoethylenically unsaturated 3 to 5 carbon atoms containing carboxylic acids, such as acrylic acid, methacrylic acid, maleic acid and / or itaconic acid, in copolymerized form, acrylic acid being preferred .
  • carboxylic acids such as acrylic acid, methacrylic acid, maleic acid and / or itaconic acid
  • the polymers contain butadiene or isoprene or mixtures of these in copolymerized form as monomers (a), butadiene polymers being preferred.
  • the proportion of butadiene and / or isoprene is preferably between 40 and 60 parts by weight.
  • the polymers should contain at least 10 parts of styrene, and they can additionally contain up to 50 parts by weight of copolymerized acrylonitrile. The total amount of styrene and acrylonitrile should not exceed 90 parts by weight. Up to 25 parts by weight of the monomers (b) can be replaced by other copolymerizable monomers, but the proportion of water-soluble monomers together should not exceed 10% by weight of the polymer. As additional water-soluble monomers such. B. acrylamide, methacrylamide, N-methylol-acrylamide and methacrylamide, vinyl sulfonic acid or its water-soluble salts and allylsulfonic acid and its water-soluble salts. Other, water-insoluble, monomers are e.g.
  • acrylic and methacrylic esters such as methyl acrylate and methacrylate, ethyl acrylate, n-butyl acrylate and methacrylate, tert-butyl acrylate, isobutyl acrylate and methacrylate and 2-ethylhexyl acrylate and methacrylate
  • vinyl esters such as vinyl acetate and vinyl propionate and vinyl halide and vinyl halide and vinylidene chloride and also hydroxyalkyl acrylates and methacrylates, such as 2-hydroxyethyl acrylate and methacrylate, 1,4-butanediol monoacrylate and 3-hydroxypropyl acrylate.
  • regulators are usually used in amounts which are conventional per se and which are 0.3 to 1% by weight, based on the amount of the monomers.
  • tetrabromethane dialkyldixanthate and preferably alkyl mercaptans, such as especially dodecyl mercaptan, in question.
  • the polymerization can be controlled in a conventional manner such that the proportion of the carboxylated rubber obtained (solid) which is soluble in dimethylformamide at room temperature is 20 to 60, preferably 25 to 50% by weight of the polymer.
  • the new process gives leather formulations with very high kink strengths in the dry and wet state which, despite improved embossability and reduced stacking tackiness, do not lag behind the kink strengths of the process according to the EP -A-0 029 170 finished leather stand back.
  • customary wetting agents can be added to the oxides or hydroxides of the divalent or trivalent metals, nonionic wetting agents being preferred.
  • organic solvents e.g. As methyl, ethyl, n-propyl and iso-propyl alcohol or ethyl glycol monoethyl ether or ketones such as acetone and methyl ethyl ketone, natural or synthetic oils such as claw oil, peanut oil or Vietnamese red oil in free and / or emulsified form and defoamers can be added.
  • Mixtures of this type are preferably used in the form of pastes in the process according to the invention.
  • commercially available opaque color pastes can also be used when dressing leather.
  • finishing agents can be applied to the leather in a manner known per se using the aqueous synthetic rubber dispersions containing carboxyl groups, pigment preparations of the type mentioned above and other additives. Casting, knife coating, brushing, spraying, brushing or plush processes can be used for this.
  • the amount of finishing agent depends on the type and pretreatment of the leather and can be easily determined by preliminary tests.
  • Priming is usually carried out in one or more orders and good hot-melted intermediate ironing or scar embossing results in a good fusion and thus a good finish of the primer.
  • the viscosity of the application can be increased by thickeners are regulated in the usual way, an increase in viscosity leading to a reduction in penetration and thereby to a higher filling action, which is of particular interest when dressing split leather and leather fiber materials.
  • z. B conventional polyurethane varnishes, collodion varnishes or collodion varnish emulsions and aqueous polyacrylate or polyurethane dispersions which can be applied by spraying and casting processes.
  • the leathers prepared according to the new process dry very quickly and show excellent dry and wet nicks, good cold flexibility and embossability as well as very good rub-through resistance and adhesion from layer to layer and very good fullness. Compared to the dressings according to EP-A-0 029 170, they also show greatly reduced stacking. This is surprising because of the virtually complete polymerization during the preparation of the binder dispersion with regard to the disclosure of EP-A-0 029 170 and GB-B-921 798 and 900 591.
  • the parts and percentages given in the following examples relate to the weight, unless stated otherwise.
  • the parts by volume given in relation to the parts by weight relate to the liter to the kilogram.
  • the mixture is heated to 60 ° C. and polymerized for 30 minutes.
  • the remaining monomer emulsion and the remaining peroxodisulfate solution are then fed in uniformly within 2 hours.
  • the polymerization is continued at 60 ° C. until the solids content is about 38% (conversion about 95%, based on the monomers).
  • the soluble proportion of the polymer is 38%.
  • the comparative dispersion (a) obtained is freed from residual monomers.
  • the carboxylated polymer contained therein has a soluble content of 17%.
  • the rest of the monomer emulsion is then fed in uniformly within 2 hours. Then polymerized at 55 ° C to a solids content of about 42% (conversion about 94%).
  • the comparative dispersion (b) obtained is freed of residual monomers by passing nitrogen through it.
  • the carboxylated polymer contained therein has a soluble fraction of 73%.
  • a reducing agent solution of 0.0025 part of sodium formaldehyde sulfoxylate dihydrate and 0.1 part of ethoxylated octylphenol (25 ethylene oxide residues) in 0.9 part of water is then added within 2 hours and the mixture is polymerized at 35 ° C. to a solids content of 30.4% (sales about 86%) after.
  • the comparative dispersion (c) obtained is freed from residual monomers under reduced pressure.
  • the carboxylated polymer dissolves completely in dimethylformamide.
  • split leather For the preparation of split leather, 100 parts of a commercially available pigment preparation each with 600 parts of the above-described dispersions 1, 2, 3, (a), (b) and (c), 200 parts of water and 40 parts of a zinc oxide paste each on page 15, below, the composition specified in EP-A-0 029 170.
  • the mixture is applied to split leather with the plush board in an amount of 12 g / m 2 , the application is ironed at 80 ° C. and then sprayed until completely covered with another mixture. After drying, mint at 80 ° C and 200 bar with a 2 sec delay. Finally, a usual finish based on a nitro emulsion varnish is applied.
  • the leathers are dried after the last spray application, with the coated side on top of one another and stored under a load of 5 kg / cm 2 at 40 ° C. for 18 hours.
  • the assessment of the wet kink resistance and dry kink resistance of the finished leather is carried out in usually using a Bally flexometer.
  • dispersions 1, 2 and 3 are used according to the dressing method described in Examples 1 to 3, but in each case without the zinc oxide dispersion being used, dressings with split leather that have practically the same physical fastness properties are obtained if the procedure is otherwise the same little loss in processing properties, d. H. a drop of 1 to 2 notes when stacking.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Paper (AREA)
  • Treatment And Processing Of Natural Fur Or Leather (AREA)
  • Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
  • Polymerisation Methods In General (AREA)
  • Synthetic Leather, Interior Materials Or Flexible Sheet Materials (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Paints Or Removers (AREA)

Description

Die vorliegende Erfindung betrifft ein Verfahren zum Zurichten von Leder mit einer carboxylierten Kautschuk-Dispersion, auf Basis von Butadien und/oder Isopren sowie Styrol und gegebenenfalls Oxiden und/oder Hydroxiden 2- und/oder 3-wertiger Metalle.The present invention relates to a process for finishing leather with a carboxylated rubber dispersion based on butadiene and / or isoprene and styrene and optionally oxides and / or hydroxides of 2 and / or 3-valent metals.

Bei der Zurichtung von vollnarbigem, geschliffenem oder gespaltenem Leder werden dessen Oberfläche mit Gemischen aus Bindemitteln und Pigmenten behandelt, um die Poren des Leders oberflächlich zu verschließen. Als Bindemittel werden dafür häufig wäßrige Polyacrylat-Dispersionen, wäßrige Dispersionen von Vinylacetat-Copolymerisaten oder wäßrige Dispersionen von synthetischen Kautschuken, d. h. Copolymerisaten von 1,3-Dienen, wie Butadien, Isopren oder Chloropren, eingesetzt. Die geeigneten Pigmente können organischer oder anorganischer Natur sein ; in Frage kommen z. B. Eisenoxid, Titandioxid, Kaolin, Phthalocyanin oder Azopigmente. Zusätzlich können derartige Zurichtungen Verdickungsmittel, z. B. auf Basis von Cellulose, wie Carboxymethylcellulose, Polyvinylalkohole, Polyacrylsäure oder deren Salze, Kasein oder Polymerisate des N-Vinylpyrrolidons, enthalten.When finishing full-grain, sanded or split leather, its surface is treated with mixtures of binders and pigments in order to superficially close the pores of the leather. Aqueous polyacrylate dispersions, aqueous dispersions of vinyl acetate copolymers or aqueous dispersions of synthetic rubbers, ie. H. Copolymers of 1,3-dienes, such as butadiene, isoprene or chloroprene, are used. The suitable pigments can be organic or inorganic in nature; come into question z. B. iron oxide, titanium dioxide, kaolin, phthalocyanine or azo pigments. In addition, such dressings can include thickeners, e.g. B. based on cellulose, such as carboxymethyl cellulose, polyvinyl alcohols, polyacrylic acid or their salts, casein or polymers of N-vinylpyrrolidone.

Bindemittel der genannten Art befriedigen jedoch beim Zurichten von Spaltleder, z. B. für Schuhoberleder, noch nicht, da sie eine schlechte Prägbarkeit, schlechte Kälteflexibilität sowie ungenügende Trocken- und Naßknickfestigkeiten zeigen.However, binders of the type mentioned are satisfactory when dressing split leather, e.g. B. for upper leather, not yet, as they show poor embossability, poor cold flexibility and insufficient dry and wet buckling strength.

Auch wäßrige Dispersionen von Carboxylgruppen aufweisenden synthetischen Kautschuk-Dispersionen wurden schon als Bindemittel beim Zurichten von Leder eingesetzt. Bei dem Verfahren der GB-B-822231 wird dabei unter Zusatz von Zinkverbindungen eine Zurichtung mit verbesserter Heißbügelfestigkeit erzielt, bei der jedoch Glanz, Fülle und Deckung sowie der Griff verschlechtert sind und beim Aufbringen verschiedener Schichten durch ungenügende Haftung der Schichten aufeinander eine schlechte Naßknickfestigkeit auftritt. Auch die aus der GB-PS 921 798 und 900591 bekannten Zurichtungen auf Basis auspolymerisierter Carboxylgruppen enthaltender Kautschuk-Dispersionen befriedigen hinsichtlich ihrer Trockenknickfestigkeit nicht.Aqueous dispersions of synthetic rubber dispersions containing carboxyl groups have also been used as binders in the finishing of leather. In the process of GB-B-822231, a dressing with improved hot ironing strength is achieved with the addition of zinc compounds, but with which the gloss, fullness and coverage as well as the grip are deteriorated and when different layers are applied due to insufficient adhesion of the layers to one another there is poor wet kink resistance . The dressings known from GB-PS 921 798 and 900591 based on rubber dispersions containing polymerized carboxyl groups are also unsatisfactory in terms of their resistance to dry kinking.

Schließlich ist aus der EP-A-0 029 170 ein Verfahren zum Zurichten von Leder bekannt, bei dem ein carboxylierter synthetischer Kautschuklatex eingesetzt wird, der nicht auspolymerisiert ist und bei dem die restlichen Monomeren entfernt sind. Der Kautschuk wird dabei nach der Batch-Wd/HB-Fahrweise (Einstufenverfahren) durch Emulsionspolymerisation von 1 bis 10 Gew.-Teilen a,ß-monoethylenisch ungesättigten aliphatischen Carbonsäuren und 90 bis 99 Gew.-Teilen eines Gemisches aus acyclischen, konjugierten Dienen mit 4 bis 9 Kohlenstoffatomen und von Vinylaromaten mit 8 bis 12 Kohlenstoffatomen und/oder (Meth)acrylnitril eines (Meth)acryinitrilgehaltes von maximal 50 Gew.-Teilen hergestellt. Das Zurichtemittel enthält 0,5 bis 50 Gew.%, bezogen auf den Kautschuk, eines oder mehrerer Oxide und/oder Hydroxide zweiwertiger Metalle wie Zinkoxid oder Magnesiumhydroxid. Zurichtungen von Spaltleder, die nach diesem Verfahren hergestellt sind, zeigen zwar guten Abschluß und Deckung, Narbenwurf, Zügigkeit, Kälteflexibilität und Haftung sowie Trocken- und Naßknickfestigkeiten, doch lassen ihre Prägbarkeit und Stapelklebrigkeit noch zu wünschen übrig.Finally, EP-A-0 029 170 discloses a process for finishing leather, in which a carboxylated synthetic rubber latex is used which is not completely polymerized and in which the remaining monomers have been removed. The rubber is mixed with the batch-Wd / HB procedure (one-stage process) by emulsion polymerization of 1 to 10 parts by weight of a, β-monoethylenically unsaturated aliphatic carboxylic acids and 90 to 99 parts by weight of a mixture of acyclic, conjugated dienes 4 to 9 carbon atoms and of vinyl aromatics with 8 to 12 carbon atoms and / or (meth) acrylonitrile with a (meth) acrylonitrile content of at most 50 parts by weight. The dressing agent contains 0.5 to 50% by weight, based on the rubber, of one or more oxides and / or hydroxides of divalent metals such as zinc oxide or magnesium hydroxide. Preparations of split leather, which are produced by this process, show good closure and coverage, grain throw, toughness, flexibility at low temperatures and adhesion as well as dry and wet buckling strengths, but their embossability and stack stickiness still leave something to be desired.

Es wurde nun gefunden, daß man Leder mit einer synthetischen carboxylierten Kautschuk-Dispersion, die durch Emulsionspolymerisation von

  • (A) 1 bis 10 Gew.-Teilen a,ß-monoethylenisch ungesättigten, 3 bis 5 C-Atome enthaltenden Carbonsäuren und
  • (B) 90 bis 99 Gew.-Teilen eines Gemisches aus
    • (a) 10 bis 90 Gew.-Teilen Butadien und/oder Isopren und
    • (b) 10 bis 90 Gew.-Teilen Styrol und/oder Acrylnitril, wobei die Menge an Acrylnitril im Gemisch bis zu 50 Gew.-Teile und die Menge an Styrol mindestens 10 Gew.-Teile beträgt, bei einem Umsatz von mehr als 90 % und anschließendes Entfernen der restlichen Monomeren hergestellt und noch mit 0 bis 50 Gew.%, bezogen auf den carboxylierten Kautschuk, eines oder mehrerer Oxide und/oder Hydroxide 2-und/oder 3-wertiger Metalle versetzt worden ist, mit Vorteil zurichten kann, wenn die carboxylierte Kautschuk-Dispersion nach dem Emulsions-Zulaufverfahren unter Abstimmen von Polymerisationstemperatur, Zusammensetzung der Monomeren, Art und Menge des Emulgators sowie Art und Menge des Reglers derart hergestellt wird, daß sie einen in Dimethylformamid bei Raumtemperatur löslichen Anteil an carboxyliertem Kautschuk von 20 bis 60 Gew.% hat. Wegen der verbesserten Verarbeitbarkeit, insbesondere der verminderten Stapelklebrigkeit kann mit derartigen carboxylierten Kautschuk-Dispersionen auch ohne Zusatz von Oxiden und/oder Hydroxiden 2- und/oder 3-wertiger Metalle gearbeitet werden. Es wird jedoch vorgezogen, derartige Oxide und/oder Hydroxide, insbesondere Zinkoxid, Zinkhydroxid, Magnesiumoxid und Magnesiumhydroxid mitzuverwenden, und diese in an sich üblicher Weise als Paste einzusetzen, die zusätzlich Netzmittel und gegebenenfalls weitere Zusätze enthält. Wegen der verminderten Stapelklebrigkeit können bei dem neuen Verfahren im Vergleich zu dem Verfahren des EP-A-0 029 170 im allgemeinen geringere Mengen an Oxiden und/oder Hydroxiden der genannten Art eingesetzt werden. Die Menge an Oxiden und/oder Hydroxiden 2- und/oder 3-wertiger Metalle liegt häufig im Bereich von 0 bis 50, meistens von 0,5 bis 50, vorzugsweise von 0,5 bis 10 Gew.%, bezogen auf den carboxylierten Kautschuk (fest).
It has now been found that leather can be treated with a synthetic carboxylated rubber dispersion obtained by emulsion polymerization of
  • (A) 1 to 10 parts by weight of a, β-monoethylenically unsaturated carboxylic acids containing 3 to 5 carbon atoms and
  • (B) 90 to 99 parts by weight of a mixture
    • (a) 10 to 90 parts by weight of butadiene and / or isoprene and
    • (b) 10 to 90 parts by weight of styrene and / or acrylonitrile, the amount of acrylonitrile in the mixture being up to 50 parts by weight and the amount of styrene being at least 10 parts by weight, with a conversion of more than 90 % and subsequent removal of the remaining monomers and 0 to 50% by weight, based on the carboxylated rubber, of one or more oxides and / or hydroxides of divalent and / or trivalent metals can advantageously be added, if the carboxylated rubber dispersion is prepared in accordance with the emulsion feed process with coordination of the polymerization temperature, composition of the monomers, type and amount of emulsifier and type and amount of regulator so that it contains a proportion of carboxylated rubber which is soluble in dimethylformamide at room temperature from 20 to 60% by weight. Because of the improved processability, in particular the reduced stacking tack, such carboxylated rubber dispersions can also be used without the addition of oxides and / or hydroxides of 2 and / or 3-valent metals. However, it is preferred to use such oxides and / or hydroxides, in particular zinc oxide, zinc hydroxide, magnesium oxide and magnesium hydroxide, and to use them in a conventional manner as a paste which additionally contains wetting agents and optionally further additives. Because of the reduced stickiness of the stack, smaller amounts of oxides and / or hydroxides of the type mentioned can generally be used in the new process compared to the process of EP-A-0 029 170. The amount of oxides and / or hydroxides of divalent and / or trivalent metals is often in the range from 0 to 50, usually from 0.5 to 50, preferably from 0.5 to 10% by weight, based on the carboxylated rubber (firmly).

Die für die Zurichtungen eingesetzten wäßrigen Dispersionen der synthetischen carboxylierten Kautschuk-Dispersionen haben im allgemeinen eine Konzentration an carboxyliertem Kautschuk von 30 bis 60, insbesondere von 35 bis 55 Gew.%. Bei der Herstellung durch das Emuisionszulaufverfahren wird, wie an sich üblich, in einer wäßrigen Vorlage ein Teil der Monomerenmischung in emulgierter Form zusammen mit einem entsprechenden Teil des Emulgators und des Polymerisationsinitiators sowie von Regler vorgelegt, die Vorlage auf Polymerisationstemperatur erwärmt und nach Anspringen der Polymerisation die restliche Monomerenemulsion, die Emulgator und im allgemeinen Regler enthält, sowie getrennt davon eine wäßrige Lösung des Polymerisationsinitiators nach Maßgabe des Verbrauchs zulaufen lassen. Man läßt dann im allgemeinen nachreagieren, so daß der Umsatz über 90, meist 95 bis 98 % beträgt. Die Polymerisationstemperatur wird dabei meist im Bereich von 45 bis 65 °C gewählt und es werden im allgemeinen übliche wasserlösliche radikalbildende Polymerisationsinitiatoren, wie Natrium-und Ammoniumpersulfat oder Redoxkatalysatoren wie tert.-Butylperbenzoat/Formaldehydsulfoxylat/Ei- sen(11) sulfat und tert.-Butylhydroperoxid/Ascorbinsäure/Eisen(II)sulfat eingesetzt. Bevorzugt werden wasserlösliche Persulfate der genannten Art. Als Emulgiermittel kommen die üblichen anionischen und nichtionischen Emulgatoren in Frage, wobei anionische Emulgatoren von besonderem Interesse sind. Als Emulgator wird vorzugsweise Natriumlaurylsulfat oder Alkylarylsulfonate mit meist 7 bis 12 C-Atomen in den Alkylgruppen eingesetzt.The aqueous dispersions of the synthetic carboxylated rubber dispersions used for the dressings generally have a carboxylated rubber concentration of 30 to 60, in particular from 35 to 55% by weight. In the production by the emulsion feed process, as usual per se, part of the monomer mixture in emulsified form together with a corresponding part of the emulsifier and the polymerization initiator as well as a regulator are introduced in an aqueous receiver, the receiver is heated to the polymerization temperature and, after the polymerization has started, the remaining monomer emulsion, which contains the emulsifier and generally regulator, and separately run an aqueous solution of the polymerization initiator according to consumption. The mixture is then generally allowed to react further, so that the conversion is over 90, mostly 95 to 98%. The polymerization temperature is usually selected in the range from 45 to 65 ° C. and generally customary water-soluble radical-forming polymerization initiators such as sodium and ammonium persulfate or redox catalysts such as tert-butyl perbenzoate / formaldehyde sulfoxylate / iron (11) sulfate and tert.- Butyl hydroperoxide / ascorbic acid / iron (II) sulfate used. Water-soluble persulfates of the type mentioned are preferred. The usual anionic and nonionic emulsifiers are suitable as emulsifiers, anionic emulsifiers being of particular interest. Sodium lauryl sulfate or alkylarylsulfonates with mostly 7 to 12 carbon atoms in the alkyl groups are preferably used as emulsifiers.

Die wäßrigen carboxylierten Kautschuk-Dispersionen enthalten 1 bis 10, vorzugsweise 1 bis 5 Gew.-Teile a,ß-monoethylenisch ungesättigte 3 bis 5 C-Atome enthaltende Carbonsäuren, wie Acrylsäure, Methacrylsäure, Maleinsäure und/oder Itaconsäure einpolymerisiert, wobei Acrylsäure vorgezogen wird. Als Monomere (a) enthalten die Polymerisate Butadien oder Isopren oder Gemische aus diesen einpolymerisiert, wobei Butadien-Polymerisate vorgezogen werden. Der Anteil an Butadien und/oder Isopren liegt vorzugsweise zwischen 40 und 60 Gew.-Teilen. Die Polymerisate sollen mindestens 10 Teile Styrol enthalten, zusätzlich können sie noch bis zu 50 Gew.-Teile Acrylnitril einpolymerisiert enthalten. Insgesamt soll die Menge an Styrol und Acrylnitril 90 Gew.-Teile nicht überschreiten. Von den Monomeren (b) können bis zu 25 Gew.-Teile durch andere copolymerisierbare Monomere ersetzt sein, doch soll der Anteil an wasserlöslichen Monomeren zusammen 10 Gew.% des Polymerisats nicht überschreiten. Als zusätzliche wasserlösliche Monomere kommen z. B. Acrylamid, Methacrylamid, N-Methylol-acrylamid und -methacrylamid, Vinylsulfonsäure oder deren wasserlösliche Salze sowie Allylsulfonsäure und deren wasserlösliche Salze in Betracht. Weitere, wasserunlösliche, Monomere sind z. B. Acryl- und Methacrylester, wie Methylacrylat und -methacrylat, Ethylacrylat, n-Butylacrylat und -methacrylat, tert.-Butylacrylat, Isobutylacrylat und -methacrylat sowie 2-Ethylhexylacrylat und -methacrylat, Vinylester, wie Vinylacetat und Vinylpropionat sowie Vinylhalogenide, wie Vinylchlorid und Vinylidenchlorid sowie ferner Hydroxialkylacrylate und -methacrylate, wie 2-Hydroxiethylacrylat und -methacrylat, 1,4-Butandiol-monoacrylat und 3-Hydroxipropylacrylat.The aqueous carboxylated rubber dispersions contain 1 to 10, preferably 1 to 5 parts by weight of a, β-monoethylenically unsaturated 3 to 5 carbon atoms containing carboxylic acids, such as acrylic acid, methacrylic acid, maleic acid and / or itaconic acid, in copolymerized form, acrylic acid being preferred . The polymers contain butadiene or isoprene or mixtures of these in copolymerized form as monomers (a), butadiene polymers being preferred. The proportion of butadiene and / or isoprene is preferably between 40 and 60 parts by weight. The polymers should contain at least 10 parts of styrene, and they can additionally contain up to 50 parts by weight of copolymerized acrylonitrile. The total amount of styrene and acrylonitrile should not exceed 90 parts by weight. Up to 25 parts by weight of the monomers (b) can be replaced by other copolymerizable monomers, but the proportion of water-soluble monomers together should not exceed 10% by weight of the polymer. As additional water-soluble monomers such. B. acrylamide, methacrylamide, N-methylol-acrylamide and methacrylamide, vinyl sulfonic acid or its water-soluble salts and allylsulfonic acid and its water-soluble salts. Other, water-insoluble, monomers are e.g. B. acrylic and methacrylic esters, such as methyl acrylate and methacrylate, ethyl acrylate, n-butyl acrylate and methacrylate, tert-butyl acrylate, isobutyl acrylate and methacrylate and 2-ethylhexyl acrylate and methacrylate, vinyl esters, such as vinyl acetate and vinyl propionate and vinyl halide and vinyl halide and vinylidene chloride and also hydroxyalkyl acrylates and methacrylates, such as 2-hydroxyethyl acrylate and methacrylate, 1,4-butanediol monoacrylate and 3-hydroxypropyl acrylate.

Bei der Herstellung der wäßrigen carboxylierten Kautschuk-Dispersionen werden meist Regler in an sich üblichen Mengen die 0,3 bis 1 Gew.%, bezogen auf die Menge der Monomeren, betragen, mitverwendet. Als solche kommen z. B. Tetrabromethan, Dialkyldixanthogenate und vorzugsweise Alkylmercaptane, wie besonders Dodecylmercaptan, in Frage. Durch geeignetes Abstimmen von Polymerisationstemperatur, Zusammensetzung der Monomeren, Art und Menge des Emulgators sowie Art und Menge des Reglers kann die Polymerisation in an sich üblicher Weise derart gesteuert werden, daß der Anteil des erhaltenen carboxylierten Kautschuk (fest), der bei Raumtemperatur in Dimethylformamid löslich ist, 20 bis 60, vorzugsweise 25 bis 50 Gew.% des Polymerisats beträgt. Wenngleich bei der Herstellung der Kautschuk-Dispersionen im allgemeinen keine Kettenabbruchmittel mitverwendet werden, erhält man doch bei dem neuen Verfahren Lederzurichtungen mit sehr hohen Knickfestigkeiten im trockenen und naßen Zustand, die trotz verbesserter Prägbarkeit und verminderter Stapelklebrigkeit nicht hinter den Knickfestigkeiten der nach dem Verfahren der EP-A-0 029 170 zugerichteten Leder zurückstehen.In the preparation of the aqueous carboxylated rubber dispersions, regulators are usually used in amounts which are conventional per se and which are 0.3 to 1% by weight, based on the amount of the monomers. As such, e.g. B. tetrabromethane, dialkyldixanthate and preferably alkyl mercaptans, such as especially dodecyl mercaptan, in question. By suitably coordinating the polymerization temperature, the composition of the monomers, the type and amount of the emulsifier and the type and amount of the regulator, the polymerization can be controlled in a conventional manner such that the proportion of the carboxylated rubber obtained (solid) which is soluble in dimethylformamide at room temperature is 20 to 60, preferably 25 to 50% by weight of the polymer. Although no chain terminators are generally used in the production of the rubber dispersions, the new process gives leather formulations with very high kink strengths in the dry and wet state which, despite improved embossability and reduced stacking tackiness, do not lag behind the kink strengths of the process according to the EP -A-0 029 170 finished leather stand back.

Bei der Herstellung von Gemischen für die Lederzurichtung können den Oxiden bzw. Hydroxiden der 2- bzw. 3-wertigen Metalle übliche Netzmittel, meist in Mengen von 20 bis 60 % ihres Gewichtes, zugesetzt werden, wobei nichtionogene Netzmittel vorgezogen werden. Zusätzlich können auch organische Lösungsmittel, z. B. Methyl-, Ethyl-, n-Propyl- und iso-Propylalkohol oder Ethylglykolmonoethylether oder Ketone, wie Aceton und Methylethylketon, natürliche oder synthetische Öle, wie Klauenöl, Erdnußöl oder Türkischrotöl in freier und/oder emulgierter Form sowie Entschäumer zugesetzt werden. Derartige Abmischungen werden bevorzugt in Form von Pasten bei dem erfindungsgemäßen Verfahren eingesetzt. Zusätzlich können bei der Zurichtung von Leder handelsübliche Deckfarbpasten mitverwendet werden.In the production of mixtures for leather finishing, customary wetting agents, usually in amounts of 20 to 60% of their weight, can be added to the oxides or hydroxides of the divalent or trivalent metals, nonionic wetting agents being preferred. In addition, organic solvents, e.g. As methyl, ethyl, n-propyl and iso-propyl alcohol or ethyl glycol monoethyl ether or ketones such as acetone and methyl ethyl ketone, natural or synthetic oils such as claw oil, peanut oil or Turkish red oil in free and / or emulsified form and defoamers can be added. Mixtures of this type are preferably used in the form of pastes in the process according to the invention. In addition, commercially available opaque color pastes can also be used when dressing leather.

Nach dem neuen Verfahren kann man vollnarbiges, geschliffenes und insbesondere auch Spaltleder oder Lederfasermaterialien zurichten. Die Zurichtungsmittel können unter Verwendung der wäßrigen synthetischen carboxylgruppen enthaltenden Kautschuk-Dispersionen, von Pigmentzubereitungen der oben genannten Art sowie weiteren Zusätzen in an sich bekannter Weise auf das Leder aufgebracht werden. Hierfür können Gieß-, Rakel-, Streich-, Spritz-, Bürst- oder Plüschprozesse angewandt werden. Die Menge an Zurichtungsmittel hängt von der Art und Vorbehandlung des Leders ab und läßt sich durch Vorversuche leicht ermitteln.With the new process, full-grain, sanded and in particular split leather or leather fiber materials can be finished. The finishing agents can be applied to the leather in a manner known per se using the aqueous synthetic rubber dispersions containing carboxyl groups, pigment preparations of the type mentioned above and other additives. Casting, knife coating, brushing, spraying, brushing or plush processes can be used for this. The amount of finishing agent depends on the type and pretreatment of the leather and can be easily determined by preliminary tests.

Meist wird dabei eine Grundierung in einem oder mehreren Aufträgen durchgeführt und durch heißes, starkes Zwischenbügeln oder Narbenprägen ein gutes Verschmelzen und dadurch ein guter Abschluß der Grundierung erreicht.Priming is usually carried out in one or more orders and good hot-melted intermediate ironing or scar embossing results in a good fusion and thus a good finish of the primer.

Bei dem neuen Zurichtungsverfahren kann die Viskosität des Auftrags durch Verdickungsmittel in an sich üblicher Weise reguliert werden, wobei eine Viskositätsanhebung zu einer Verminderung des Eindringvermögens und dadurch zu einer höheren Füllwirkung führt, was beim Zurichten von Spaltleder und Lederfasermaterialien von besonderem Interesse ist.With the new dressing process, the viscosity of the application can be increased by thickeners are regulated in the usual way, an increase in viscosity leading to a reduction in penetration and thereby to a higher filling action, which is of particular interest when dressing split leather and leather fiber materials.

Als Schlußappretur auf erfindungsgemäß zugerichtetem Leder eignen sich z. B. übliche Polyurethanlacke, Kollodiumlacke bzw. Kollodiumlack-Emulsionen sowie wäßrige Polyacrylat- oder Polyurethan-Dispersionen, die durch Spritz- und Gießverfahren aufgetragen werden können.As a final finish on leather prepared according to the invention, z. B. conventional polyurethane varnishes, collodion varnishes or collodion varnish emulsions and aqueous polyacrylate or polyurethane dispersions which can be applied by spraying and casting processes.

Die nach dem neuen Verfahren zugerichteten Leder trocknen sehr rasch und zeigen hervorragende Trocken- und Naßnickfestigkeiten, gute Kälteflexibilität und Prägbarkeit sowie sehr gute Durchreibfestigkeit und Haftung von Schicht zu Schicht und sehr gute Fülle. Sie zeigen zudem im Vergleich zu den Zurichtungen gemäß der EP-A-0 029 170 stark vermindertes Stapelkleben. Dies ist wegen des praktisch vollständigen Auspolymerisierens bei der Herstellung der Bindemittel-Dispersion im Hinblick auf die Offenbarung der EP-A-0 029 170 sowie der GB-B-921 798 und 900 591 überraschend.The leathers prepared according to the new process dry very quickly and show excellent dry and wet nicks, good cold flexibility and embossability as well as very good rub-through resistance and adhesion from layer to layer and very good fullness. Compared to the dressings according to EP-A-0 029 170, they also show greatly reduced stacking. This is surprising because of the virtually complete polymerization during the preparation of the binder dispersion with regard to the disclosure of EP-A-0 029 170 and GB-B-921 798 and 900 591.

Die im folgenden angegebenen löslichen Anteile des carboxylierten Kautschuks werden wie folgt bestimmt :

  • Aus einer 30 %igen wäßrigen Dispersion des carboxylierten Kautschuks wird ein Film gegossen und dieser nach dem Trocknen im Klimaraum bei 25 °C und 70% relativer Luftfeuchtigkeit 48 Stunden gelagert. Ein 1 cm2 großes Stück des erhaltenen Films wird 24 Stunden in Dimethylformamid (über einem 0,4 nm Molekularsieb getrocknet) aufbewahrt, das Dimethylformaldehyd über einen Quarzfilter abgegossen und der Rückstand im Trockenschrank bei 120 °C 5 Stunden getrocknet. Aus der Masse des in einem Exsikkator abgekühlten Dimethylformamid-Rückstands wird der gelöste Anteil berechnet.
The soluble proportions of the carboxylated rubber indicated below are determined as follows:
  • A film is cast from a 30% aqueous dispersion of the carboxylated rubber and, after drying in a climatic room, is stored at 25 ° C. and 70% relative atmospheric humidity for 48 hours. A 1 cm 2 piece of the film obtained is kept in dimethylformamide (dried over a 0.4 nm molecular sieve) for 24 hours, the dimethylformaldehyde is poured off through a quartz filter and the residue is dried in a drying cabinet at 120 ° C. for 5 hours. The dissolved fraction is calculated from the mass of the dimethylformamide residue cooled in a desiccator.

Die in den folgenden Beispielen angegebenen Teile und Prozente beziehen sich, wenn nicht anders angegeben, auf das Gewicht. Die darin angegebenen Volumenteile verhalten sich zu den Gewichtsteilen wie das Liter zum Kilogramm.The parts and percentages given in the following examples relate to the weight, unless stated otherwise. The parts by volume given in relation to the parts by weight relate to the liter to the kilogram.

I. Herstellung der wäßrigen Dispersionen der carboxylierten KautschukeI. Preparation of the aqueous dispersions of the carboxylated rubbers Dispersion 1Dispersion 1

In einem mit Rührer ausgestatteten Autoklaven von 160 Volumenteilen werden 7,5 Teile Wasser, 0,09 Teile Natriumperoxodisulfat und 7,5 Teile einer Emulsion, hergestellt aus 30,9 Teilen Wasser, 15 Teilen Butadien, 8,1 Teilen Acrylnitril, 5,1 Teilen Styrol, 0,9 Teilen Acrylsäure, 0,18 Teilen tert.-Dodecylmercaptan, 0,3 Teilen Natriumlaurylsulfat, 0,9 Teilen Methacrylamid und 0,3 Teilen des Natriumsalzes der Dodecylbenzolsulfonsäure vorgelegt. Man heizt auf 55 °C auf und polymerisiert 10 min an. Dann gibt man den Rest der Emulsion gleichmäßig innerhalb von 3 Stunden zu. Anschließend wird bei 55 °C nachpolymerisiert bis der Feststoffgehalt 42% (etwa 94% Umsatz der Monomeren) erreicht ist. Die erhaltene Dispersion 1 wird von restlichen Monomeren unter Durchleiten von Stickstoff befreit. Das darin enthaltene Polymerisat hat einen löslichen Anteil von 23 %.In an autoclave equipped with a stirrer of 160 parts by volume, 7.5 parts of water, 0.09 parts of sodium peroxodisulfate and 7.5 parts of an emulsion, prepared from 30.9 parts of water, 15 parts of butadiene, 8.1 parts of acrylonitrile, 5.1 Parts of styrene, 0.9 parts of acrylic acid, 0.18 parts of tert-dodecyl mercaptan, 0.3 parts of sodium lauryl sulfate, 0.9 parts of methacrylamide and 0.3 parts of the sodium salt of dodecylbenzenesulfonic acid. The mixture is heated to 55 ° C. and polymerized for 10 minutes. Then you add the rest of the emulsion evenly within 3 hours. Polymerization is then carried out at 55 ° C. until the solids content is 42% (approximately 94% conversion of the monomers). The dispersion 1 obtained is freed of residual monomers while passing nitrogen through. The polymer contained therein has a soluble content of 23%.

Dispersion 2Dispersion 2

In einem mit Rührer ausgestatteten Autoklaven von 50 Volumenteilen werden 5 Teile Wasser, 0,01 Teile Natriumlaurylsulfat, 0,04 Teile Natriumpyrophosphat, 0,005 Teile Natriumsalz der Ethylendiamintetraessigsäure, 0,0025 Teile Natriumformaldehydsulfoxylat-dihydrat und 2 Teile einer Emulsion, bestehend aus 5,4 Teilen Butadien, 1 Teil Acrylnitril, 3 Teilen Styrol, 0,3 Teilen Acrylsäure, 0,3 Teilen Methacrylamid, 0,06 Teilen tert.-Dodecyimercaptan, 0,1 Teilen Natriumlaurylsulfat und 8,2 Teilen Wasser und 0,5 Volumenteile einer Lösung von 0,08 Teilen Natriumperoxodisulfat in 2 Teilen Wasser vorgelegt. Man heizt auf 60 °C auf und polymerisiert 30 min an. Anschließend wird die restliche Monomerenemulsion und die restliche Peroxodisulfatlösung gleichmäßig innerhalb von 2 Stunden zugefahren. Man polymerisiert bei 60 °C nach bis der Feststoffgehalt etwa 38 % (Umsatz etwa 95 %, bezogen auf die Monomeren) beträgt. Nach dem Austreiben der restlichen Monomeren aus der erhaltenen Dispersion 2 beträgt deren Feststoffgehalt 40 %. Der lösliche Anteil des Polymerisats beträgt 38%.5 parts of water, 0.01 part of sodium lauryl sulfate, 0.04 part of sodium pyrophosphate, 0.005 part of sodium salt of ethylenediaminetetraacetic acid, 0.0025 part of sodium formaldehyde sulfoxylate dihydrate and 2 parts of an emulsion consisting of 5.4 parts are placed in an autoclave equipped with a stirrer and having 50 parts by volume Parts of butadiene, 1 part of acrylonitrile, 3 parts of styrene, 0.3 part of acrylic acid, 0.3 part of methacrylamide, 0.06 part of tert-dodecyimercaptan, 0.1 part of sodium lauryl sulfate and 8.2 parts of water and 0.5 part by volume of a solution of 0.08 parts of sodium peroxodisulfate in 2 parts of water. The mixture is heated to 60 ° C. and polymerized for 30 minutes. The remaining monomer emulsion and the remaining peroxodisulfate solution are then fed in uniformly within 2 hours. The polymerization is continued at 60 ° C. until the solids content is about 38% (conversion about 95%, based on the monomers). After the remaining monomers have been driven off from the dispersion 2 obtained, its solids content is 40%. The soluble proportion of the polymer is 38%.

Dispersion 3Dispersion 3

In einem mit Rührer ausgestatteten Autoklaven von 160 Volumenteilen werden 12 Teile Wasser, 0,075 Teile tert.-Butylhydroperoxid (80%ig), 0,03 Teile Natriumpyrophosphat und 15 Volumenteile einer Emulsion aus 31 Teilen Wasser, 15 Teilen Isopren, 8,1 Teilen Acrylnitril, 5,1 Teilen Styrol, 0,9 Teilen Methacrylamid, 0,9 Teilen Acrylsäure, 0,18 Teilen tert.-Dodecylmercaptan, 0,45 Teilen Natriumlaurylsulfat und 0,45 Teilen Natriumdodecylbenzolsulfonat vorgelegt und auf 60 °C erhitzt. Dann wird 1 Teil einer Lösung von 0,015 Teilen Natriumsalz der Ethylendiamintetraessigsäure, 0,0075 Teilen Eisen-II-sulfatheptahydrat und 0,03 Teilen Natrium-formaldehyd-sulfoxylat-dihydrat in 3 Teilen Wasser zugegeben und eine 1/4 Stunde anpolymerisiert. Innerhalb von 4 Stunden wird dann der Rest der Monomeren-Emulsion und der Reduktionsmittellösung zugegeben und bis zu einem Feststoffgehalt von 38,5 % (97 % Umsatz) bei 60 °C nachpolymerisiert. Nach dem Austreiben der restlichen Monomeren aus der erhaltenen Dispersion 3 unter vermindertem Druck beträgt dessen Feststoffgehalt 39,5 %. Der lösliche Anteil des carboxylierten Polymerisats beträgt 52 %.In an autoclave equipped with a stirrer of 160 parts by volume, 12 parts of water, 0.075 parts of tert-butyl hydroperoxide (80% strength), 0.03 parts of sodium pyrophosphate and 15 parts by volume of an emulsion of 31 parts of water, 15 parts of isoprene and 8.1 parts of acrylonitrile , 5.1 parts of styrene, 0.9 parts of methacrylamide, 0.9 parts of acrylic acid, 0.18 parts of tert-dodecyl mercaptan, 0.45 parts of sodium lauryl sulfate and 0.45 parts of sodium dodecylbenzenesulfonate and heated to 60 ° C. Then 1 part of a solution of 0.015 part of sodium salt of ethylenediaminetetraacetic acid, 0.0075 part of iron (II) sulfate heptahydrate and 0.03 part of sodium formaldehyde sulfoxylate dihydrate in 3 parts of water is added and the mixture is polymerized for 1/4 hour. The remainder of the monomer emulsion and the reducing agent solution are then added within 4 hours and postpolymerization is carried out at 60 ° C. up to a solids content of 38.5% (97% conversion). After the remaining monomers have been driven off from the obtained Dispersion 3 under reduced pressure has a solids content of 39.5%. The soluble proportion of the carboxylated polymer is 52%.

Vergleichsdispersion (a)Comparative dispersion (a)

In einem mit Rührer ausgestatteten Autoklaven von 50 Volumenteilen werden 1 Teil Wasser, 0.03 Teile Kaliumperoxodisulfat, 2,5 Volumenteile einer Emulsion aus 10,4 Teilen Wasser, 5 Teilen Butadien. 2,7 Teilen Acrylnitril, 1,7 Teilen Styrol, 0,3 Teilen Acrylsäure, 0,3 Teilen Methacrylamid, 0.3 Teilen Natriumlaurylsulfat, 0,3 Teilen Natriumsalz der Dodecylbenzolsulfonsäure, 0,092 Teilen Natriumsulfat und 0,03 Teilen tert.-Dodecylmercaptan sowie 0,2 Volumenteile einer Lösung von 0,000 2 Teilen Natriumformaldehydsulfoxylat, 0,0008 Teilen Eisennitrat und 0,0006 Teilen Natriumsalz der Ethylendiamintetraessigsäure in 2 Teilen Wasser vorgelegt und das Gemisch auf 70 °C erwärmt. Nach 1/4 Stunde Anpolymerisieren wird der Rest der Monomerenemulsion und der Lösung des Reduktionsmittels innerhalb von 4 Stunden zugefahren. Man polymerisiert dann bei 70 °C bis zu einem Feststoffgehalt von etwa 42 % (etwa 95 % Umsatz) nach. Die erhaltene Vergleichsdispersion (a) wird von restlichen Monomeren befreit. Das darin enthaltene carboxylierte Polymerisat hat einen löslichen Anteil von 17 %.In an autoclave equipped with a stirrer of 50 parts by volume, 1 part of water, 0.03 parts of potassium peroxodisulfate, 2.5 parts by volume of an emulsion of 10.4 parts of water and 5 parts of butadiene. 2.7 parts of acrylonitrile, 1.7 parts of styrene, 0.3 parts of acrylic acid, 0.3 parts of methacrylamide, 0.3 parts of sodium lauryl sulfate, 0.3 parts of sodium salt of dodecylbenzenesulfonic acid, 0.092 parts of sodium sulfate and 0.03 parts of tert-dodecyl mercaptan and 0 , 2 parts by volume of a solution of 0.000 2 parts sodium formaldehyde sulfoxylate, 0.0008 parts iron nitrate and 0.0006 parts sodium salt of ethylenediaminetetraacetic acid in 2 parts water and the mixture heated to 70 ° C. After 1/4 hour of polymerization, the rest of the monomer emulsion and the solution of the reducing agent are added within 4 hours. Polymerization is then carried out at 70 ° C. to a solids content of approximately 42% (approximately 95% conversion). The comparative dispersion (a) obtained is freed from residual monomers. The carboxylated polymer contained therein has a soluble content of 17%.

Vergleichsdispersion (b)Comparative dispersion (b)

In einem mit Rührer ausgestatteten Autoklaven von 160 Volumenteilen werden 7,5 Teile Wasser, 0,09 Teile Natriumperoxodisulfat sowie 2,5 Volumenteile eines Gemisches, bestehend aus 31,3 Teilen Wasser, 15 Teilen Butadien, 8,1 Teilen Acrylnitril, 5,1 Teilen Styrol, 0,9 Teilen Acrylsäure,'0,9 Teilen Methacrylamid, 0,45 Teilen Natriumlaurylsulfat, 0,45 Teilen Natriumsalz der Dodecylbenzolsulfonsäure und 0,45 Teilen tert.-Dodecylmercaptan vorgelegt. Man heizt auf 55 °C auf und polymerisiert 10 min lang an. Dann wird der Rest der Monomerenemulsion gleichmäßig innerhalb von 2 Stunden zugefahren. Anschließend polymerisiert man noch bei 55 °C bis zu einem Feststoffgehalt von etwa 42 % (Umsatz etwa 94 %) nach. Die erhaltene Vergleichsdispersion (b) wird unter Durchleiten von Stickstoff von restlichen Monomeren befreit. Das darin enthaltene carboxylierte Polymerisat hat einen löslichen Anteil von 73 %.In an autoclave equipped with a stirrer of 160 parts by volume, 7.5 parts of water, 0.09 parts of sodium peroxodisulfate and 2.5 parts by volume of a mixture consisting of 31.3 parts of water, 15 parts of butadiene, 8.1 parts of acrylonitrile, 5.1 Parts of styrene, 0.9 parts of acrylic acid, 0.9 parts of methacrylamide, 0.45 parts of sodium lauryl sulfate, 0.45 parts of sodium salt of dodecylbenzenesulfonic acid and 0.45 parts of tert-dodecyl mercaptan. The mixture is heated to 55 ° C. and polymerized for 10 minutes. The rest of the monomer emulsion is then fed in uniformly within 2 hours. Then polymerized at 55 ° C to a solids content of about 42% (conversion about 94%). The comparative dispersion (b) obtained is freed of residual monomers by passing nitrogen through it. The carboxylated polymer contained therein has a soluble fraction of 73%.

Vergleichsdispersion (c)Comparative dispersion (c)

In einem mit Rührer ausgestatteten Kessel von 50 Volumenteilen werden 18 Teile Wasser, 5 Teile Butadien, 2,7 Teile Acrylnitril, 1,7 Teile Styrol, 0,3 Teile Methacrylsäure, 0,3 Teile Methacrylamid, 0,05 Teile tert.-Dodecylmercaptan, 0,2 Teile Natriumsulfonat eines Gemisches langkettiger Paraffinkohlenwasserstoffe einer mittleren Kettenlänge von 15 C-Atomen als Emulgator, sowie 0,002 5 Teile Natrium-formaldehyd-sulfoxylat-dihydrat und 0,005 Teile tert.-Butylhydroperoxid vorgelegt und auf 35 °C erwärmt. Man gibt dann innerhalb von 2 Stunden eine Reduktionsmittellösung von 0,0025 Teilen Natriumformaldehyd-sulfoxylat-dihydrat und 0,1 Teil ethoxyliertem Octylphenol (25 Ethylenoxid-Reste) in 0,9 Teilen Wasser zu und polymerisiert bei 35 °C bis zu einem Feststoffgehalt von 30,4 % (Umsatz etwa 86 %) nach. Die erhaltene Vergleichsdispersion (c) wird unter vermindertem Druck von restlichen Monomeren befreit. Das carboxylierte Polymerisat löst sich vollständig in Dimethylformamid.18 parts of water, 5 parts of butadiene, 2.7 parts of acrylonitrile, 1.7 parts of styrene, 0.3 part of methacrylic acid, 0.3 part of methacrylamide and 0.05 part of tert-dodecyl mercaptan are placed in a kettle of 50 parts by volume equipped with a stirrer , 0.2 parts of sodium sulfonate of a mixture of long-chain paraffinic hydrocarbons with an average chain length of 15 carbon atoms as emulsifier, and 0.002 5 parts of sodium formaldehyde sulfoxylate dihydrate and 0.005 parts of tert-butyl hydroperoxide and heated to 35 ° C. A reducing agent solution of 0.0025 part of sodium formaldehyde sulfoxylate dihydrate and 0.1 part of ethoxylated octylphenol (25 ethylene oxide residues) in 0.9 part of water is then added within 2 hours and the mixture is polymerized at 35 ° C. to a solids content of 30.4% (sales about 86%) after. The comparative dispersion (c) obtained is freed from residual monomers under reduced pressure. The carboxylated polymer dissolves completely in dimethylformamide.

11. Zurichtung von Leder11. Dressing leather Beispiele 1 bis 3 und Vergleichsbeispiele (a) bis (c)Examples 1 to 3 and Comparative Examples (a) to (c)

Für die Zurichtung von Spaltleder werden jeweils 100 Teile einer handelsüblichen Pigmentpräparation mit jeweils 600 Teilen der oben beschriebenen Dispersionen 1, 2, 3, (a), (b) bzw. (c), jeweils 200 Teilen Wasser sowie jeweils 40 Teilen einer Zinkoxidpaste der auf Seite 15, unten, der EP-A-0 029 170 angegebenen Zusammensetzung, verrührt. Das Gemisch wird mit dem Plüschbrett in einer Menge von 12 g/m2 auf Spaltleder aufgetragen, der Auftrag bei 80 °C gebügelt und anschließend bis zur vollständigen Deckung mit weiterem Gemisch gespritzt. Nach dem Trocknen prägt man bei 80 °C und 200 bar mit 2 sec Verzögerung. Abschließend wird eine übliche Appretur auf Basis eines Nitroemulsionslacks aufgetragen.For the preparation of split leather, 100 parts of a commercially available pigment preparation each with 600 parts of the above-described dispersions 1, 2, 3, (a), (b) and (c), 200 parts of water and 40 parts of a zinc oxide paste each on page 15, below, the composition specified in EP-A-0 029 170. The mixture is applied to split leather with the plush board in an amount of 12 g / m 2 , the application is ironed at 80 ° C. and then sprayed until completely covered with another mixture. After drying, mint at 80 ° C and 200 bar with a 2 sec delay. Finally, a usual finish based on a nitro emulsion varnish is applied.

Zur Beurteilung des Stapelklebens werden die Leder im Anschluß an den letzten Spritzauftrag getrocknet, mit der beschichteten Seite aufeinander gelegt und unter einer Belastung von 5 kg/cm2 18 Stunden bei 40 °C gelagert.To assess the stacking, the leathers are dried after the last spray application, with the coated side on top of one another and stored under a load of 5 kg / cm 2 at 40 ° C. for 18 hours.

Das dabei zu beobachtende Verhalten wird wie folgt beurteilt :

  • Note 1 = Abschälen der Filmschichten beim Auseinanderziehen der Leder
  • Note 2 = starkes Kleben, starke Beschädigung der Oberflächen
  • Note 3 = Kleben, leichte Beschädigung der Oberflächen
  • Note 4 = leichtes Kleben ohne Beschädigung der Oberflächen
  • Note 5 = kein Kleben, keine Beschädigung der Oberflächen.
The behavior to be observed is assessed as follows:
  • Note 1 = peeling off the film layers when pulling the leather apart
  • Grade 2 = strong sticking, severe damage to the surfaces
  • Grade 3 = gluing, slight damage to the surfaces
  • Note 4 = easy gluing without damaging the surfaces
  • Grade 5 = no sticking, no damage to the surfaces.

Die Beurteilung der Naßknickfestigkeit und Trockenknickfestigkeit der zugerichteten Leder erfolgt in üblicher Weise unter Verwendung eines Bally-Flexometers.The assessment of the wet kink resistance and dry kink resistance of the finished leather is carried out in usually using a Bally flexometer.

Die bei den einzelnen Zurichtungen beobachteten Werte sind für die erfindungsgemäßen Beispiele in Tabelle 1, für die Vergleichsbeispiele in der folgenden Tabelle 2 zusammengestellt.

Figure imgb0001
Figure imgb0002
 The values observed for the individual dressings are summarized in Table 1 for the examples according to the invention and in Table 2 below for the comparative examples.
Figure imgb0001
Figure imgb0002

Werden die Dispersionen 1, 2 und 3 nach der bei den Beispielen 1 bis 3 beschriebenen Zurichtungsmethode, jeweils jedoch ohne Mitverwendung der Zinkoxid-Dispersion eingesetzt, so erhält man bei sonst gleicher Arbeitsweise Zurichtungen auf Spaltleder, die praktisch gleich gute physikalische Echtheiten aufweisen, doch treten dabei geringe Einbußen bei den Verarbeitungseigenschaften, d. h. ein Abfall um 1 bis 2 Noten beim Stapelkleben auf.If the dispersions 1, 2 and 3 are used according to the dressing method described in Examples 1 to 3, but in each case without the zinc oxide dispersion being used, dressings with split leather that have practically the same physical fastness properties are obtained if the procedure is otherwise the same little loss in processing properties, d. H. a drop of 1 to 2 notes when stacking.

Claims (3)

1. A process for finishing leather with a synthetic carboxylated rubber dispersion which is prepared by emulsion polymerization of
(A) from 1 to 10 parts by weight of one or more a,(3-monoethylenically unsaturated carboxylic acids of 3 to 5 carbon atoms, and
(B) from 90 to 99 parts by weight of a mixture of
(a) from 10 to 90 parts by weight of butadiene and/or isoprene, and
(b) from 10 to 90 parts by weight of styrene and/or acrylonitrile, the mixture containing not more than 50 parts by weight of acrylonitrile and not less than 10 parts by weight of styrene,

with a conversion of more than 90 %, and subsequent removal of the remaining monomers, and to which from 0 to 50 % by weight, based on the carboxylated rubber, of one or more oxides and/or hydroxides of divalent and/or trivalent metals are added, wherein the carboxylated rubber dispersion is prepared by the emulsion feed method, with correlation of the polymerization temperature, the composition of the monomers and the type and amount of the emulsifier and of the regulator, in such a way that it contains from 20 to 60% by weight of carboxylated rubber which is soluble in dimethylformamide at room temperature.
2. A process as claimed in claim 1, wherein, in the synthetic rubber used, up to 25 parts by weight of the copolymerized water-insoluble monomers are replaced by other copolymerizable monomers, the total amount of water-soluble additional monomers being not more than 10% by weight, based on the carboxylated rubber.
3. A process as claimed in claim 1 or 2, wherein the leather is treated with a rubber dispersion and a paste which consists of a mixture of metal oxides and/or hydroxides, wetting agents and, if desired, other additives.
EP19840105470 1983-05-19 1984-05-14 Method of finishing leather with a synthetic carboxylated rubber latex Expired EP0127055B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3318219A DE3318219A1 (en) 1983-05-19 1983-05-19 METHOD FOR MAKING LEATHER WITH A SYNTHETIC CARBOXYLATED RUBBER DISPERSION
DE3318219 1983-05-19

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EP0127055A1 EP0127055A1 (en) 1984-12-05
EP0127055B1 true EP0127055B1 (en) 1987-01-21

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US5221284A (en) * 1989-02-18 1993-06-22 Basf Aktiengesellschaft Method of coating leather using aqueous synthetic resin dispersions
DE4244006A1 (en) * 1992-12-24 1994-06-30 Bayer Ag Cationic pigment binders
ITPI20130078A1 (en) 2013-09-04 2015-03-05 Kemas S R L TIRE TIRE PROCESS FOR GETTING FULL-FULL SKINS AND ELASTICITY AND OBTAINED PRODUCTS

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GB822231A (en) * 1957-07-01 1959-10-21 Bayer Ag Process for dressing leather
US2949386A (en) * 1958-11-03 1960-08-16 Interchem Corp Non-woven fabrics
DE1174937B (en) * 1959-06-04 1964-07-30 Bayer Ag Process for dressing leather
DE1224428B (en) * 1960-04-28 1966-09-08 Bayer Ag Coating and impregnating agent based on aqueous mixed polymer emulsions
US3344103A (en) * 1965-03-08 1967-09-26 Goodrich Co B F Self curing synthetic latices
US3865622A (en) * 1972-12-26 1975-02-11 Princeton Polymer Lab Carboxylated acrylonitrile-butadiene latex fabric coating
DE2946435C2 (en) * 1979-11-17 1982-02-18 Bayer Ag, 5090 Leverkusen Process for dressing leather by treating it with rubber latices

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DE3462152D1 (en) 1987-02-26
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DE3318219A1 (en) 1984-11-22
JPH021880B2 (en) 1990-01-16
JPS59221400A (en) 1984-12-12

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