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
  • 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 carboxylated rubber latices from conjugated dienes, vinyl aromatics and / or (meth) acrylonitrile by reaction with oxides and / or hydroxides of divalent metals.
• Aqueous copolymer dispersions are generally used as binders. These copolymer dispersions are polyacrylate dispersions, dispersions of copolymers of vinyl acetate with acrylic esters or ethylene or synthetic rubber dispersions.
• pigments are those of inorganic and organic provenance, for example iron oxide, titanium dioxide, kaolin, azo pigments and phthalocyanines.
• the formulations can contain conventional thickeners, e.g. those based on cellulose, such as carboxymethyl cellulose, polyvinyl alcohols, poly-N-vinylpyrrolidones, polyacrylic acid and their salts and casein.
• copolymer dispersions are satisfactory when used on full-grain and sanded leathers, but not on split leathers.
• French patent 1 197 476 describes a process for the heat ironing of leather by treatment with polymer dispersions containing carboxylic acid groups in the presence of zinc compounds. This method can improve the hot ironing strength of the dressing, but it does cover, calm the surface, shine, fill and grip. worsened. In particular due to ironing processes between the individual top coat applications, adhesion problems arise between the individual layers as a result of networking. The upper layer becomes insufficient on the lower layer. anchored so that one leather with poor wet buckling strength and wet grip.
• top layers on leather with particularly good properties important for leather finishing such as finishing and covering, grain and toughness, flexibility at low temperatures and adhesion, dry and wet rub fastness properties, but especially very good dry and wet crease resistance, excellent embossability and layer adhesion are, if one carries out the treatment of the leather with carboxylated synthetic rubber latexes, in the manufacture of which only a monomer conversion of 70-95% by weight, preferably 80-90% by weight, is polymerized, and the latices in the The leather is treated with oxides and / or hydroxides of divalent metals.
• the rubber latex is preferably reacted with 1 to 20% by weight, based on solid rubber, of one or more oxides and / or hydroxides of divalent metals.
• ß, ß-monoethylenically unsaturated mono- and dicarboxylic acids are: acrylic acid, methacrylic acid, itaconic, fumaric and maleic acids and monoesters of these dicarboxylic acids, e.g. Monoalkyl itaconate, fumarate and maleate.
• Suitable acyclic conjugated dienes with 4 to 9 carbon atoms are, for example, butadiene- (1,3), 2-methylbutadiene- (1,3) (isoprene), 2,3-dimethylbutadiene- (1,3), piperylene, 2- Neopentylbutadiene- (1,3) and other substituted dienes such as 2-chlorobutadiene- (1,3) (chloro pren), 2-cyanobutadiene- (1,3) and substituted straight-chain conjugated pentadienes and straight-chain or branched hexadienes.
• the ability to copolymerize particularly well with vinyl aromatics and (meth) acrylonitrile makes butadiene (1,3) the preferred monomer.
• Suitable vinyl aromatics are those in which the vinyl group is bonded directly to a core consisting of 6 to 10 carbon atoms.
• examples include: styrene and substituted styrenes such as 4-methylstyrene, 3-methylstyrene, 2,4-dimethylstyrene, 4-isopropylstyrene, 4-chlorostyrene, 2,4-dichlorostyrene, divinylbenzene, ⁇ -methylstyrene and vinylnaphthalene.
• styrene is the preferred monomer.
• water-insoluble monomers can be replaced by one or more copolymerizable monomers, in particular by (meth) acrylic acid alkyl esters, such as, for example, methyl, ethyl, h-propyl, isopropyl, n-butyl, isobutyl and 2-ethylhexyl (meth) acrylate, mono- and diesters of alkane diols and ⁇ , ⁇ -monoethylenically unsaturated monocarboxylic acids such as ethylene glycol mono (meth) acrylate, propylene glycol mono (meth) acrylate, ethylene glycol di (meth) acrylate, Butanediol-1,4-di (meth) acrylate, amides ⁇ , ⁇ -monoethylenically unsaturated mono- and dicarboxylic acids such as acrylamide and methacrylamide and their N-methylol compounds and N-al
• Monomers bearing sulfonic acid groups such as, for example, styrene sulfonic acid, (meth) allylsulfonic acid or their water-soluble salts, are also suitable.
• Other comonomers that can be used are vinyl esters of carboxylic acids having 1 to 18 carbon atoms, in particular vinyl acetate and vinyl propionate, vinyl chloride and vinylidene chloride, vinyl ethers such as vinyl methyl ether, vinyl ketones such as vinyl ethyl ketone and heterocyclic monovinyl compounds such as vinyl pyridine.
• the synthetic rubber latices for leather finishing suitable for the process according to the invention are produced by single-stage emulsion polymerization (batch polymerization) at temperatures between 0 and 60 ° C. and pH values between 2 and 12. For this purpose, in an amount of 0.5 to 20% by weight .-% (based on monomers) anionogenic, cationogenic or nonionic emulsifiers and dispersants or combinations thereof.
• anionogenic emulsifiers are salts of higher fatty acids and resin acids, higher fatty alcohol sulfates, higher alkyl sulfonates and alkylarylsulfonates and their condensation products with formaldehyde, higher hydroxyalkyl sulfonates, salts of sulfosuccinic acid esters and sulfated ethylene oxide adducts.
• cationic emulsifiers are salts of alkyl-, aryl- and alkylarylamines with inorganic acids, salts of quaternary ammonium compounds and alkylpyridinium salts.
• nonionic emulsifiers e.g. the known reaction products of ethylene oxide with fatty alcohols, such as lauryl, myristyl, cetyl, stearyl and oleyl alcohol, with fatty acids such as lauric, myristic, palmitic, stearic and oleic acid and their amides and alkylphenols such as isooctyl, isononyl and dodecylphenol find application.
• fatty alcohols such as lauryl, myristyl, cetyl, stearyl and oleyl alcohol
• fatty acids such as lauric, myristic, palmitic, stearic and oleic acid and their amides and alkylphenols
• alkylphenols such as isooctyl, isononyl and dodecylphenol find application.
• reaction products of ethylene oxide with isononyl, dodecyl, tetradecyl mercaptan and higher alkyl mercaptans and higher alkyl thiophenols or similar reaction products of etherified or esterified polyhydroxy compounds with a longer alkyl chain such as sorbitol monostearate are examples.
• the compounds given as examples are reacted with 4-60 or more moles of ethylene oxide.
• block copolymers of ethylene oxide and propylene oxide with at least one mole of ethylene oxide can also be used here.
• Suitable initiators are e.g. inorganic peroxo compounds such as hydrogen peroxide, sodium, potassium or ammonium peroxodisulfate, peroxocarbonates and borate peroxy hydrates, furthermore organic peroxo compounds such as acyl hydroperoxides, diacyl peroxides, alkyl hydroperoxides, dialkyl peroxides and esters such as tert-butyl perbenzoate.
• the amount of initiator is generally within the limits of 0.01-5% by weight, based on the total amount of the monomers used.
• the inorganic or organic peroxo compounds given as examples can also be used in a known manner in combination with suitable reducing agents.
• suitable reducing agents May be mentioned: sulfur dioxide, alkali disulfites, alkali and ammonium hydrogen sulfites, thiosulfate, dithionite and formaldehyde sulfoxylate, furthermore hydroxylamine hydrochloride, hydrazine sulfate, iron (II) sulfate, tin (II) chloride, titanium (III) sulfate, hydroquinone, glucose, ascorbic acid and certain amines.
• metal salts the cations of which can exist in more than one valence level.
• metal salts examples are copper, manganese, iron, cobalt and nickel salts.
• Chain transfer agents such as tetrabromomethane, tetrabromethane, lower and higher alcohols, higher alkyl mercaptans and dialkyldixanthogenates can also be used in the polymerization.
• the type and amount of chain transfer agents depend, inter alia, on the effectiveness of the chain transfer agent and on the amount of diene used. Therefore, the selection and amount of chain transfer agent is of particular importance because hereby both the Schichtenhaftun g of leather finishes made from the rubber lattices, and their buckling strength in the dry and wet state can be optimized within certain limits.
• Suitable chain terminators are, for example, sodium dimethyldithiocarbamate, hydroxylamine, dialkylhydroxylamine, hydrazine hydrate and hydroquinone.
• the latex is freed of residual monomers in a manner known per se.
• latices can be produced whose solids content is between 1 and 65% by weight. usually, however, L atices are used with solids contents between 30 and 50 wt .-%.
• the synthetic rubber latices according to the invention are in themselves not suitable for the finishing of leather, but only lead to outstanding application advantages in combination with oxides and / or hydroxides of divalent metals which react with the carboxyl groups of the copolymer.
• Suitable oxides of divalent metals are, for example. Barium, magnesium, calcium and zinc oxide, the latter being particularly preferred. These oxides are obtained by calcining the corresponding finely divided carbonates.
• the corresponding hydroxides can be precipitated from the aqueous solutions of the corresponding salts by adding alkali or by reacting the oxides with water.
• the leather can therefore also be prepared by using aqueous solutions of the divalent metals and producing the corresponding hydroxides in situ by adding alkali.
• the oxides and / or hydroxides of divalent metals are additionally organic solvents such as alcohols, e.g. Methyl, ethyl, n-propyl and isopropyl alcohol or ethylene 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 suitable defoamers are added.
• organic solvents such as alcohols, e.g. Methyl, ethyl, n-propyl and isopropyl alcohol or ethylene 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 suitable defoamers are added.
• the processing can be done on full-grain, sanded and split leather or leather fiber materials of any provenance.
• the finishes are applied to the leather in a manner known per se using the copolymer latices according to the invention, pigment preparations of the type mentioned above and other additives.
• the dressings can be applied by casting, knife coating, brushing, spraying, brushing or plush processes.
• the amount of finishing depends on the type and pretreatment of the leather and can be easily determined by preliminary tests.
• the primer is carried out in one or more orders. Hot, strong intermediate ironing or scar embossing results in a good fusion and thus a good finish of the primer. Then an upper top coat can be applied with the same liquor.
• the viscosity of the rubber latices can be regulated by adding thickeners of the type mentioned at the outset, so that the penetration can easily be reduced by increasing the viscosity.
• the thickened rubber latices are particularly suitable for dressing split leather due to the resulting higher filling effect and the improved film-forming ability.
• a mixture of 18,000 g of water, 5000 g of butadiene (1,3), 3000 g of acrylonitrile, 1700 g of styrene, 333 g of 90% methacrylic acid and 50 g of tert is tert in a 40-1 stainless steel autoclave with a cross bar stirrer.
• a solution of 100 g of a reaction product of isononylphenol with 20 moles of ethylene oxide and 2.5 g of Rongalit C in 500 g of water is then pressed in and the polymerization is continued at 35 ° C. After reaching a solids concentration of about 31% (about 86% conversion), the polymerization is stopped with a solution of 200 g of 25% diethylhydroxylamine in 200 g of water.
• the latex A obtained is freed of residual monomers and has a solids concentration of 31%.
• Example 2 The experiment described in Example 1 is repeated, but the sodium pa used as the emulsifier raffinsulfonate replaced by the same amount of sodium lauryl sulfate. After a solids concentration of about 28% (approx. 77% conversion) has been reached, the polymerization is terminated with a solution of 200 g of 25% diethylhydroxylamine in 200 g of water. The latex B obtained is freed of residual monomers and has a solids concentration of 28%.
• a mixture of 18,000 g of water, 500 g of butadiene- (1,3) ", 3000 g of acrylonitrile, 1900 g of styrene, 100 g of itaconic acid and 50 g of tert-dodecyl mercaptan are mixed using 200 g of a sodium sulfonate of a mixture of long-chain paraffin hydrocarbons with a medium chain length of 15 carbon atoms as an emulsifier and 5 g of 70% tert-butyl hydroperoxide and 2.5 g of sodium formaldehyde sulfoxylate (Rongalit C) as an initiator system in a 40-1 stainless steel autoclave with a cross bar stirrer at 35 ° C to a solids content of After this concentration has been reached, a solution of 100 g of 20-fold ethoxylated isononylphenol and 2.5 g of Rongalit C in 500 g of water is added and the polymerization is continued at
• crosslinking pastes are used to carry out the dressing process according to the invention, the production of which is described below by way of example.
• the mixture is stirred intensively for a further 15 minutes.
• claw oil 20 parts of claw oil are at 80 ° C in 15 parts of a vinyl pyrrolidone copolymer and. Emulsified 1 part of an adduct of about 30 moles of ethylene oxide with 1 mole of isononylphenol using a high-speed stirrer. With further stirring, 49 parts of water and 15 parts of powdered magnesium hydroxide are added.
• the mixture is stirred intensively for a further 15 minutes.
• the entire mixture (100 parts) is then ground once on a bead mill.
• the split leather or polished vachettes to be treated receive 1 to 2 applications by means of a brush, plush board, airless gun, spraying or casting machine.
• the total application amount is approximately 150-300 g / m 2 .
• the leather is ironed or scarred at 100 ° C and 350 bar with a 2 - 5 second delay.
• the top color is applied with the same liquor (application approx. 100 - 200 g / m 2 ).
• a common collodion varnish is applied as a finish by spraying or pouring.
• the dressing obtained has the advantageous properties specified in the description.
• Vegetable retanned split leather or polished vachettes are prepared using a highly concentrated liquor. 200 parts of a commercially available pigment paste based on casein are mixed with 60 parts of paste B. 40 parts of water and then 700 parts of latex B are added to this mixture. The viscosity of the paint liquor corresponds to a run-out time of 20 - 35 seconds in a Ford cup with a 4 mm nozzle.
• the dressing is carried out as described in Example 1.
• the application properties of the dressing correspond to the advantageous properties described in the general part.
• nappa leather to be treated 100 parts of a commercially available pigment paste based on casein are mixed with 60 parts by weight of paste A. 540 parts of water are added to this mixture with stirring and finally 300 parts of latex C.
• the nappa leather to be treated is given 1 to 2 applications using a plush board, air spray or airless gun. After drying, the leathers are ironed at 70 ° C and 150 bar. Then you mill the nappa leather for 1 to 2 hours in the barrel. Then the top coat of paint is applied with the same liquor by 1 or 2 spraying jobs using an air or airless gun. At the end, a common collodion varnish or a varnish based on polyurethane is applied by spray application.
• the finished leathers show a good aspect and have high physical fastness properties, especially dry and wet buckling strength, wet rub fastness and cold flexibility. They are very millfest; Even with a relatively thick coating, the leathers are pleasantly soft and do not appear overloaded.
• the grain of grain is fine, the grain and grain are elegant. The flames are small.

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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)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Synthetic Leather, Interior Materials Or Flexible Sheet Materials (AREA)

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• 1979
  • 1979-11-17 DE DE2946435A patent/DE2946435C2/de not_active Expired
• 1980
  • 1980-11-05 EP EP80106796A patent/EP0029170B2/fr not_active Expired
  • 1980-11-05 DE DE8080106796T patent/DE3065841D1/de not_active Expired
  • 1980-11-12 US US06/206,069 patent/US4330597A/en not_active Expired - Lifetime
  • 1980-11-14 CA CA000364730A patent/CA1142817A/fr not_active Expired
  • 1980-11-14 ES ES496847A patent/ES8306507A1/es not_active Expired
  • 1980-11-14 JP JP15970580A patent/JPS5684800A/ja active Granted
  • 1980-11-17 BR BR8007487A patent/BR8007487A/pt not_active IP Right Cessation

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