DE1278064B - Process for dressing leather - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN 4MWWk PATENT OFFICE Int. Cl .:

C14 c

EDITORIAL

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German class: 28a-9

P 12 78 064.2-43 (F 48025)

December 28, 1965

19th September 1968

The invention relates to a process for finishing leather with the aid of aqueous copolymer dispersions, the aminomethylene carboxamide groups which are N-substituted in the side chain of the polymer molecule contain.

It is known to use conversion products for the priming of leather before the actual finishing of the covering color of isocyanates with polyesters in organic solvents, or aqueous emulsifier-free polyacrylate dispersions, which at least 10% acrylamide included in polymerized form should be used. This treatment of the leather surface Even on leathers of moderate grain strength, a fine grain break, smooth surface and good scratch resistance achieved.

However, these processes have the disadvantage if known aqueous polymer dispersions are used that hardening of the leather is associated with the hardening of the grain, which means that the use excludes the known primer in certain leather qualities.

When using preparations based on isocyanates dissolved in organic solvents the adhesive strength of the subsequent top layer is greatly reduced if the primed as Leather in the meantime, e.g. B. must be stored over the weekend.

The German Auslegeschrift 1 182 769 also describes a method for dressing leather known. Aqueous dispersions or solutions of copolymers are used for this, which inter alia polymerized units of Mannich bases of α, / ϊ-unsaturated carboxamides contain. However, dispersions of these copolymers are not used as grain-strengthening agents for leather sufficient.

The invention now relates to a method for dressing leather using aqueous copolymer dispersions which are N-substituted in the side chain of the polymer molecule Aminomethylencarboxamide groups, characterized in that one contains such Dispersions of copolymers used, 0.1 to 10% of monomers of which are N-substituted Aminomethylene carboxamides of the general formula

CH ₂ = CHR - CO - NH - CH ₂ -NH - COOR '

(I)

consist, where R is hydrogen or R and / or R ' denote an alkyl, cycloalkyl, aryl or aralkyl radical.

Process for dressing leather

Applicant:

Paint factories Bayer Aktiengesellschaft,

5090 Leverkusen

Named as inventor:

Dr. Günter KoIb, 5000 Cologne-Stammheim;

Dr. Kurt Eitel, 5670 Opladen;

Dr. Wolfgang Speicher, 5090 Leverkusen;

Karl Berger, 5670 Opladen

With the aid of the copolymer dispersions to be used according to the invention, on the one hand, one can A primer that solidifies the grain and does not harden the leather, which further improves the adhesive strength of the subsequent top layers even after a long period of storage before further finishing and which has a very good scratch resistance, smoothness and uniformity of the surface of the finished Leather results. On the other hand, you get tack-free cover layers with a very soft handle and excellent fastness properties.

Compounds of the general formula (I) are, for example, amidomethylene carbamic acid esters Acrylic and methacrylic acid, such as the methyl esters, ethyl esters, propyl esters, isopropyl esters, butyl esters, Isobutyl ester, cyclohexyl ester, phenyl ester or benzyl ester. You can follow the procedure of the German Patent 1195 739 can be obtained.

Amidomethylene carbamic acid esters are of preferred importance here of acrylic and methacrylic acid, which as an ester component is the remainder of a saturated, contain monohydric aliphatic alcohol with 1 to 4 carbon atoms.

There are mainly used aqueous copolymer dispersion, which in addition to 0.1 to 10 ⁰ / o monomers of the general formula (I) as a further copolymerizable monomers elasticizing acting monomers from the group of conjugated 1,3-diolefins having 4 to 6 carbon atoms, such as butadiene 1,3, 2-methylbutadiene-1,3 or 2-chlorobutadiene-1,3, esters or acrylic acid with 1 to 20 carbon atoms in the ester radical, preferably the esters of monohydric, aliphatic saturated alcohols with 1 to 20 carbon atoms, such as acrylic

809 617/524

Acid methyl ester, ethyl ester, butyl ester, isobutyl, those which contain 1,3-diolefins in polymerized form, esters, dodecyl esters or octadecyl esters, and meth are expedient before their use with acrylic acid esters mixed with 4 to 20 carbon atoms in the stabilizers mentioned, such as. B. Ester radical, preferably the esters of monovalent, ali- condensation products of cresols with camphene, Phatic saturated alcohols with 4 to 20 carbons- 5 2,6-di-tert-butyl-p-cresol, aralkylation products Substance atoms, such as butyl methacrylate, isobutyl of diphenylamine or 2,2'-methylenebis (4-methyl ester, -äthylhexylester, -dodecylester or -octadecyl- 6-cyclohexyIphenol). The amount of stabilizing esters included in polymerized form. This elasticizing agent should be 0.2 to 5%, based on the active monomers are preferably in amounts 1,3-diene content of the copolymers. Even from 70 to 99.9 Vo, based on total monomers, to understandably can be used for the aqueous copolymers. dispersions, other well-known aids as well

To build up the low and high molecular weight copolymer dispersions used according to the invention can optionally be set to e.g. B. their viscosity, their stability Radically copolymerizable, double binders, their drying time or their course, or else Monomers containing fertilizers can be used to influence the properties of the leather finishing The following may be mentioned by way of example: the methacrylic acids. Furthermore, the copolymer dispersions, esters with 1 to 3 carbon atoms containing the 1,3-diolefins in copolymerized form, also with Alcohol residues, vinyl esters such as vinyl acetate, vinyl vulcanizing agents such as sulfur, sulfur spen propionate or vinyl benzoate, unsaturated carbons, tetramethylthiuram disulfide, Hydrogen such as ethylene or propylene, unsaturated zinc oxide and accelerators or organic per-halogenated hydrocarbons such as vinyl chloride or oxides are added.

1,1-dichloroethylene, vinyl aromatics such as styrene, the primer of the leather according to the invention

«-Methylstyrene or vinyltoluene,«, ^ - unsaturated processes according to the invention using the carboxylic acids mentioned such as acrylic acid or methacrylic acid, th copolymer dispersions can, depending on the suction itaconic acid, Fumaric acid or maleic acid, as well as by hand, with a brush or Derivatives of the «, ^ - unsaturated carboxylic acids such as the spray gun or with the casting machine or Acrylic acid amide or methacrylic acid amide, 2-oxy with airless spray units. It is through Propyl methacrylate or 2-AminoäthylmethacryIat- attempts that order amount per square meter Hydrochloride, 2-vinylpyridine or 2-methyl-5-vinyl- to determine the effect of good scar hardening pyridine. 3 °, the surface smoothness and the optimal

Of preferred interest are the third-party components that provide scratch resistance. Serving varies depending on the leather to mention: styrene, acrylonitrile, acrylamide and the same between 10 and 30 g of solid substance of the erfin methacrylamide, Acrylic acid and methacrylic acid, copolymer dispersions used according to the invention, vinyl acetate and methyl methacrylate, with leather per square meter.

Acrylamide and methacrylamide in amounts of small 35 It goes without saying that to control the Less than 5%, based on total monomers, a penetration capacity of the primer mixture is reduced should be. The same is also customary in the finishing

The production of the copolymer dispersions, wetting and dispersing agents, such as Turkish red oils, can be done by known methods. The ge-anionic and non-ionic emulsifiers, called water Monomers become miscible using common free organic solvents such as ethyl alcohol radicals forming polymerization catalysts in hol, isopropyl alcohol and wax dispersions, aqueous Polymerized dispersions. Has proven itself can be set. For the coloring of the green here The polymerization at pH values around or dierung approach can in the leather finishing over below 7 and 50 ° C not significantly exceed borrowed aniline dyes and also in smaller quantities the temperatures. It is easily possible - 45 pigment colors are used, or should here under the term copolymerization A particularly favorable effect with regard to upper

be agreed -, the production of the poly surface rest is achieved when the leather after merisate in the form of a graft or block copoly- made primer again on a broad carry out merization, with one or a grinding machine that augments the entire leather surface the monomers with a prepolymer to 5 ° summarizes, is ground. This is done using sandpaper End to be polymerized. Grain sizes 400 to 900 are advantageously used as emulsifiers. the the known compounds of anionic and / or aqueous polymers used according to the invention cationic and / or nonionic type dispersions are particularly suitable for this turns. The aliphatic fatty acid processes are preferred because, surprisingly, they are already used in the Sulphates and sulphonates in amounts of 1 to 10%, 55 drying alone at room temperature not included on total monomers, called like Lorol- depends on the pH value, so in contrast to known sulfate, Oleyl alcohol sulfate, sulfuric acid-esterified copolymer dispersions also in alkaline products of condensation of a medium, cross-link and thus insoluble, no longer Fatty alcohol or fatty alcohol mixture with ethylene thermoplastic films result. Also show oxide, fatty acid tauride or -N-methyl tauride or 60 they have a very good penetration ability into the leather Sodium alkyl sulfonates with 12 to 18 carbon atoms. and in spite of their great softness prevent the

To regulate the molecular weight, the turned sandpaper can be smeared and smeared in a short time known polymerization regulators, such as Alkylmer- so that it is unusable, which is a great cost captans or alkyl disulfides can be used. It is and would take time also possible, by a corresponding variation of 65 The further finishing of the leather is carried out according to the Amount of activator and / or temperature, chain shape known conditions of the so-called ironing and to influence the chain length of the macromolecules. driving and with the used for this procedure aqueous copolymer dispersions, especially lent casein-containing or casein-free pigment

paints, polymer dispersions and casein or collodion preparations. Here, the claims according to the Copolymer dispersions in whole or in part as a soft polymer binder can be used in the top layers. In addition to the emulsifiers mentioned, protective colloids, such as polyvinyl alcohols, can then also be partially saponified Polyvinyl esters, cellulose ethers, polyacrylic acid salts, polyacrylamide, polyvinylpyrrolidone and others similar active substances are added. The copolymer dispersions used according to the invention have a reducing effect on the tackiness of the top layers when ironing on the hydraulic Press out and when storing in a stack and result in dressings with a very soft, supple handle with excellent fastness properties, especially for looks the solvent resistance and hot iron fastness.

Rice η i ρ 1 1
^p

Heavily retanned cowhide leather that has been sanded twice with 240 grade paper is made using Airless gun treated with 20 g per qfs of the following approach:

100 g Turkish red oil
100 to 200 g of a commercially available driver from one

non-ionic emulsifier and one

water-miscible organic solvents

solvent
300 g water, '
300 g of a 40% aqueous copolymer

sat dispersions as described below.

After application, the leather is allowed to pass through a strongly ventilated but unheated drying tunnel run, its length in meters of the belt speed of the application unit per minute. After passing through the drying tunnel, the Leather stacked on a pile while still damp. There was no evidence of sticking together in the stack. The next morning the leathers are sanded on a sanding machine with 600 grade paper.

The following orders are carried out according to the guidelines as given in W. G r a ß m a η η, manual for Gerbereichemie und Lederfabrikation, Vol. 3/1, pp. 878 to 881, Table 12, for the ironing of Grinding box are shown, carried out further. A very soft leather with good grain consolidation is obtained with a smooth, calm surface, fine grain and adhesive top layers.

The copolymer dispersion used was prepared as follows:

1240 parts of oleyl alcohol sulfate, 135 parts of fatty acid N-methyl tauride with 14 to 18 carbon atoms in the fatty acid chain 135 parts of sodium pyrophosphate, 412.5 parts of methacrylamide and 150 parts of methacrylamidomethylene carbamic acid ethyl ester in 36 500 parts of water are given.

It was heated to 45 "C and gave with stirring a mixture of 2365 parts of ethyl acrylate, 2255 parts of butyl acrylate, 660 parts of acrylonitrile and 110 parts of acrylic acid in the autoclave and activated by adding 14 parts of sodium pyrosulfite dissolved in 500 parts of water and 138 parts Potassium persulfate dissolved in 3000 parts of water. After 3 hours, a mixture of 9,460 parts was added Ethyl acrylate, 9020 parts of butyl acrylate, 2640 parts of acrylonitrile and 440 parts of acrylic acid within a further 3 hours and obtained a 40% aqueous solution after a further 4 hours Copolymer dispersion.

Example 2

Instead of the copolymer dispersion described in Example 1, according to the conditions of the Example 1 used the dispersion obtained in the following way:

275 parts of methacrylamide, 275 parts of butyl methacrylamidomethylene carbamate, 1100 parts of paraffin sulfonate with 12 to 18 carbon atoms and 100 parts of fatty acid N-methyl tauride with 14 to 18 carbon atoms in the fatty acid chain were dissolved in 40,000 parts of water and placed in a VA autoclave. The mixture was heated with stirring at 5O ⁰ C, was 200 parts of potassium persulfate and gave batchwise a mixture of 11000 parts of ethyl acrylate, butyl acrylate 11550 parts, 1100 parts of methyl methacrylate, 1100 parts of acrylic acid and 2200 parts of acrylonitrile

^{a5 according} · ^{After ms} § ^otal 10 hours was the PoIymerisatausbeute nearly 100 Vo.

After dressing you get a soft, good grain-hardened leather with a smooth, calm surface, fine grain and adhesive top layers.

Example 3

Instead of the monomer composition used in Example 1 a dispersion was prepared with the following monomers under the conditions of Example 1:

11,000 parts of ethyl acrylate, 12,100 parts Acrylic acid butyl ester, 550 parts of acrylic acid, 2750 parts of acrylonitrile, 550 parts of acrylamide and 550 parts of methacrylamidomethylene carbamic acid phenyl ester. At a polymerization temperature of 50 ° C., almost 100% were obtained after a total of 12 hours Polymer yield.

The dispersion obtained is used according to the conditions of Example 1.

After dressing, the result is a soft, well-grain-consolidated leather with a smooth, calm surface, fine grain and adhesive top layers.
To> ie 1 4

An opaque paint approach

100 parts of an aqueous opaque paint mixture

(S- W. Graßmann, Handbuch der

Gerbereichemie and leather production,

_{Q u 5Q T} y ^ commercial binder

casein-based
_{1 (1T} ■ .. TiirVicr4irntni '

_5O o parts of water and

* j \ j \ j xciic tv aa a ei uiiu

200 I rush to the one described below

40% i2en wäßrieen Coüolvmerisatdispersion <- ° P ^ol y ^mensat

is applied by means of burst, spray or pour application retanned, sanded chrome cowhide leather applied. The job is up to sufficient coverage of the leather repeated 2 to 3 times. To

After the top layers have dried, a customary egg white-based finish is applied can be fixed with 10% aqueous formaldehyde solution by spray application. The received the absolutely aging-resistant finish S is characterized by its particularly soft, pleasant and non-sticky finish Handle, good grain coverage and excellent fastness properties.

The copolymer dispersion used was prepared as follows:

In a VA autoclave, the solution of 27 parts of oleyl alcohol sulfate, 3 parts of sodium pyrophosphate, 3 parts of fatty acid N-methyl tauride with a fatty acid of 14 to 18 carbon atoms and 0.3 parts of sodium pyrosulfite in 900 parts of water and stirred at 45 ° C 20% The following monomer mixture was added: 246 parts of ethyl acrylate, 240 parts of butyl acrylate, 60 parts of acrylonitrile, 12 parts of acrylic acid, 12 parts of methacrylamide and 30 parts of ethyl acrylamidomethylene carbamate. It was then activated by adding 3 parts of potassium persulfate and, when the reaction had subsided, the residual monomer mixture was added in batches. After about 10 hours the polymerization was complete and obtained 40% aqueous copolymer dispersion.

Claims (4)

Patent claims: 1. A process for dressing leather using aqueous copolymer dispersions which contain N-substituted aminomethylene carboxamide groups in the side chain of the polymer molecule, characterized in that such copolymer dispersions are used in which 0.1 to 10% of the monomers of the polymer molecule from N -substituted aminomethylene carboxamides of the general formula CH ₂ = CHR - CO - NH - CH., -NH- COOR ' consist, where R is hydrogen or R and / or R 'is an alkyl, cycloalkyl, aryl or aralkyl radical mean. 2. The method according to claim 1, characterized in that one aqueous dispersions of Copolymers used, which in addition to 0.1 to 10% monomers of the general formula (I) elastifying monomers from the group of conjugated 1,3-diolefins with 4 to 6 carbon atoms, esters of acrylic acid with 1 to 20 carbon atoms in the ester residue and Esters of methacrylic acid and 4 to 20 carbon atoms in the ester group and optionally contain further free-radically copolymerizable monomers in copolymerized form. 3. The method according to claim 1, characterized in that aqueous dispersions of Copolymers are used, which a) 0.1 to 10% compounds of the general my formula (I), b) 70 to 99.9% ester of acrylic acid with 1 to 20 carbon atoms in the ester group and optionally c) contain 29.9 to 0% of further free-radically copolymerizable monomers in copolymerized form. 4. The method according to claim 2 and 3, characterized in that fatty acid sulfates as emulsifiers and / or fatty acid sulfonates in amounts of 1 to 10%, based on total monomers, can be used. Considered publications:
German interpretative document No. 1182 769. 809 617/524 9.68 © Bundesdruckerei Berlin