EP2580356A1

EP2580356A1 - Process for producing leather

Info

Publication number: EP2580356A1
Application number: EP11795273.9A
Authority: EP
Inventors: Andreas Kunst; Jochen Ammenn
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2010-06-14
Filing date: 2011-06-14
Publication date: 2013-04-17
Also published as: EP2580356A4; WO2011158168A1; CN102939393A

Abstract

A process for producing leather comprises treating a wet blue, a wet white or a pelt in an aqueous float with a mixture of (A) at least one alkoxylate of at least one triazine having at least two functional groups per molecule, and (B) at least one alkoxylate of ammonia or at least one compound having at least two functional groups selected from primary or secondary amino groups and hydroxyl groups.

Description

Process for the production of leather

The present invention relates to a process for the production of leather, which comprises treating semi-finished products or pelts in an aqueous liquor with a mixture of

(A) at least one alkoxylate of at least one triazine having at least two functional groups per molecule and

(B) at least one alkoxylate of ammonia or at least one compound having at least two functional groups selected from primary or secondary amino groups and hydroxyl groups.

In recent years, a profound change has been observed in the leather industry. Great emphasis was placed on the development of environmentally friendly leather auxiliaries such as tanning and retanning agents. The emission of formaldehyde is highly undesirable both during the manufacture of leather and in finished leather products. Therefore, tanning agents and tannins have been developed which allow the production of low-formaldehyde leather, for example glutaraldialdehyde. Many demands are placed on leather, which can not yet be optimally solved by most tanning agents and retanning agents. The requirements include, for example, the mechanical and haptic properties of the leather, the coloration, levelness and brilliance of the color, the heat yellowing resistance and the yellowing resistance.

WO 2008/1 10532 discloses alkoxylated melamines which can be used as tannin and in particular as retanning agent.

In many cases, however, one wishes that the softness of the leather improves and the feel of the leather is even more pleasant.

Accordingly, the method defined at the outset was found, also briefly referred to as the method according to the invention. The inventive method is based on semi-finished products or pelts. In the context of the present invention, pelts are termed depilated hides of dead animals, for example dead cattle, pigs, goats or deer, which may have been freed from horns. It is not essential for the method according to the invention whether the animals were killed, for example, by slaughtering or have died of natural causes. The skins of dead animals can be pretreated by conventional methods. For example, conventional methods of pre-treatment include liming, deliming, pickling and pimpling, as well as mechanical operations such as skinning the skins. To carry out the process according to the invention, treatment is carried out in an aqueous liquor. Aqueous liquors are understood to mean aqueous formulations whose essential liquid constituent is water. Aqueous liquors may contain one or more organic solvents, for example, ethanol, isopropanol or ethylene glycol. Preferably, aqueous liquors contain less than 5% by weight of organic solvent, based on water, more preferably less than 0.5% by weight. Most preferably, aqueous liquors in the present invention contain no organic solvent.

To carry out the process according to the invention is treated with a mixture of

(A) at least one alkoxylate of at least one triazine having at least two functional groups per molecule, also called alkoxylate (A) for short, and (B) at least one alkoxylate of ammonia or at least one compound having at least two functional groups, in short also alkoxylate (B ), wherein functional groups selected from primary or secondary amino groups and hydroxyl groups. In the context of the present invention, alkoxylates (A) are understood as meaning reaction products of triazine having at least two functional groups per molecule, abbreviated triazine (a), with one or more equivalents of alkylene oxide, preferably C 2 -C 5 -alkylene oxide, for example with ethylene oxide, 1, 2-propylene oxide, 1, 2-butylene oxide or 1, 2-pentenoxide or mixtures of one or more of the aforementioned C2-Cs-alkylene oxides, preferably with one or more equivalents of ethylene oxide per functional group of triazine (a).

In a variant of the present invention, the preparation of alkoxylate (A) is carried out using a triazine (a) and a mixture of 80 to 99.9% by weight of ethylene oxide and 0.1 to 50% by weight of propylene oxide, preferably up to 20 Wt .-% of propylene oxide, based on the total amount of alkoxylate (A).

Examples of functional groups on triazine (a) are S-H groups, hydroxyl groups and amino groups, which may be primary or secondary, preferably primary amino groups. The functional groups on triazine (a) may be different or the same, for example, it may be an NH 2 group and an OH group, they are preferably the same. The functional groups can be bonded to the triazine ring via a spacer or can be bonded directly to the triazine ring, preferably they are directly linked to the triazine ring.

Triazine (a) may carry two or more functional groups, preferably two or three. In one embodiment of the present invention, alkoxylate (A) alkoxylates of at least one compound of the general formula (I) are selected.

wherein R ^{1 is} selected from NH ₂ ,

C 1 -C 10 -alkyl, branched or preferably unbranched, for example methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, neo-pentyl, 1, 2-dimethylpropyl, iso-amyl, n-hexyl, iso-hexyl, sec-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, especially methyl, n-butyl or n-nonyl; and C 6 -C 14 aryl, for example 1-naphthyl, 2-naphthyl, 1-antracenyl, 2-antracenyl, 9-antracenyl, preferably phenyl, in each case unsubstituted or mono- or polysubstituted by C 1 -C ₄ -alkyl. In one embodiment of the present invention, alkoxylate (A) is selected from alkoxylates of triazines (a) having at least two primary amino groups per molecule.

Particularly preferred examples of triazine (a) are benzoguanamine, acetoguanamine, caprinoguanamine and especially melamine.

If triazine (a) carries one or more Nh groups, then of these Nh groups in alkoxylate (A) one or both protons may be substituted by alkoxide radicals, preferably both are substituted by alkoxide radicals. In one embodiment of the present invention, triazine (a) is alkoxylated with 1 to 50 molecules, preferably 1 to 20, particularly preferably 1 to 10 molecules of alkylene oxide per functional group.

Alkoxylates (B) in the context of the present invention are reaction products of ammonia or at least one compound having at least two functional groups, abbreviated to compound (b), with one or more equivalents of alkylene oxide, in particular C 2 -C 5 -alkylene oxide, for example with Ethylene oxide, 1, 2-propylene oxide, 1, 2-butylene oxide or 1, 2-pentenoxide or mixtures of one or more of the aforementioned C2-Cs-alkylene oxides, preferably with one or more equivalents of ethylene oxide per functional group of compound (b).

Of course, compound (b) is different from triazine (a).

In one variant of the present invention, compound (b) is used to prepare alkoxylate (B) and a mixture of from 80 to 99.9% by weight of ethylene oxide and from 0.1 to 20% by weight of propylene oxide, based on total Amount of alkoxylate (B). In one embodiment of the present invention, compound (b) is alkoxylated with 1 to 50 molecules, preferably 1 to 20, particularly preferably 1 to 10 molecules of alkylene oxide per functional group.

Examples of compounds (b) are diols, triols, tetraols, amino alcohols having at least one primary or secondary amino group, mercaptoalcohols, primary or secondary diamines, triamines having a total of 3 primary or secondary amino groups, furthermore higher alcohols such as, for example, pentoles and hexols ,

Examples of amino alcohols are ethanolamine, isopropanolamine, the isomeric aminophenols, Ν, Ν-diethanolamine, N-methylmonoethanolamine, N-methyldiethanolamine, N-methylaminophenol, triethanolamine, tris (hydroxymethyl) aminomethane, triisopropanolamine and N, N-dimethylethanolamine.

Examples of suitable diols, triols and higher alcohols (polyols) such as tetrols, pentols and hexols are ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1, 3-propanediol, 1, 4-butanediol, neopentyl glycol, 1, 5-pentanediol, 3-methyl -1, 5-pentanediol, 1, 6-hexanediol, 1, 9-nonanediol, 2-methyl-1, 8-octanediol, cyclohexanediol and 1, 4-dicyclohexanedimethanol, glycerol, 1,1,1-trimethylolpropane, 1, 1 , 1-trimethylolbutane, trimethylolethane, pentaerythritol, sucrose, sucrose, glucose, fructose, mannose, dipentaerythritol, tripentaerythritol, furthermore sugar alcohols such as mannitol, xylitol and in particular sorbitol, furthermore polyesters such as, for example, polyesters based on dicarboxylic acids and diols, for example Adipic acid and 1, 4-butanediol or 1, 6-hexanediol or ethylene glycol. Also suitable are polyesters obtainable by ring-opening polymerization of ω-lactones, in particular of ε-caprolactone, with difunctional initiators.

Examples of suitable diamines and triamines are 1, 3-diaminopropane, diethylenediamine, 2,3-toluenediamine, 2,4-toluenediamine, 2,6-toluenediamine, the isomeric phenylenediamines and mixtures of two or more of the abovementioned compounds (b). In one embodiment of the present invention, alkoxylate (B) is selected from alkoxylates of at least one triol or triamine.

In another embodiment of the present invention, alkoxylate (B) is selected from alkoxylates of at least one sugar alcohol, for example mannitol, xylitol and preferably sorbitol, in particular as D - (-) sorbitol.

Particularly preferred compounds (b) are ammonia, 2,3-toluenediamine, ethylenediamine, triisopropanolamine, triethanolamine, ethylene glycol, propylene glycol, glycerol, 1,1,1-trimethylolpropane and sorbitol, in particular as D - (-) - sorbitol.

The preparation of mixtures of alkoxylate (A) and alkoxylate (B) is known per se. Thus, alkoxylate (A) and alkoxylate (B) can be prepared separately and mixed together. It is preferred to prepare alkoxylate (A) and alkoxylate (B) by alkoxylation of a mixture of triazine (a) and compound (b) in one step, as described, for example, in DE 34 12 082 A1.

In one embodiment of the present invention, alkoxylate (A) and alkoxylate (B) are selected in a weight ratio ranging from 95: 5 to 5:95, preferably from 3: 7 to 7: 3, more preferably from 2: 3 to 3: second

In one embodiment of the present invention, mixtures of alkoxylate (A) and alkoxylate (B) are selected from those prepared by alkoxylating a mixture of triazine (a) and compound (b), wherein triazine (a) and compound (b ) in a weight ratio ranging from 95: 5 to 5:95, preferably from 3: 7 to 7: 3, more preferably from 2: 3 to 3: 2 have been used.

In one embodiment of the present invention, a mixture of alkoxylate (A) and alkoxylate (B) is used which has a hydroxyl number in the range of 20 to 1000 mg KOH / g, preferably in the range of 50 to 400 mg KOH / g , particularly preferably in the range of 100 to 300 mg KOH / g, measured in each case according to DIN 53240.

In one embodiment of the present invention, a mixture of alkoxylate (A) and alkoxylate (B) having a number average molecular weight (M _n ) in the range from 300 to 5,000 g / mol, preferably in the range from 500 to 3,000 g / mol, measured, for example, by gel permeation chromatography (GPC), for example as determined against polystyrene as standard.

In one embodiment of the present invention, a mixture of alkoxylate (A) and alkoxylate (B) is used, which at 25 ° C. has a dynamic viscosity in the range from 100 to 100,000 mPa.s, preferably 100 to 10,000 mPa.s, particularly preferred 500 to 5,000 mPa-s, determined according to DIN 51550. In one embodiment of the present invention, at least one alkoxylate, abbreviated to alkoxylate (C), is additionally treated with (C) by at least one primary C 1 -C 30 -alkanol, abbreviated to alkanol (c), preferably by at least one primary cyan. C2o-alkanol.

Suitable primary alkanols (c) are, in particular, methanol, ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol, n-octanol, n-decanol, n-dodecanol, n-tetradecanol, stearyl alcohol and n-eicosanol.

Suitable secondary alkanols (c) are, for example, isopropanol and sec-butanol.

In one embodiment of the present invention, alkanol (c) is alkoxylated with 1 to 50 molecules, preferably 1 to 20, particularly preferably 1 to 10 molecules of alkylene oxide per functional group.

Alkylene oxide is as defined above. Particularly preferred alkylene oxide is ethylene oxide. In one embodiment of the present invention, compound (b) is alkoxylated with 1 to 50 molecules, preferably 1 to 20, particularly preferably 1 to 10 molecules of alkylene oxide per functional group.

In one embodiment of the present invention, up to 50% by weight of alkoxylate (C), preferably at most 20% by weight of alkoxylate (C), based on the total amount of alkoxylate (A), alkoxylate (B), are used. and alkoxylate (C).

In another embodiment of the present invention, no alkoxylate (C) is used.

In one embodiment of the present invention, a mixture of alkoxylate (A), alkoxylate (B) and alkoxylate (C) is used which has a hydroxyl number in the range of 20 to 1000 mg KOH / g, preferably in the range of 50 to 400 mg KOH / g, particularly preferably in the range of 100 to 300 mg KOH / g, measured in each case according to DIN 53240.

In one embodiment of the present invention, a mixture of alkoxylate (A), alkoxylate (B) and alkoxylate (C) having a number average molecular weight (M _n ) in the range of 300 to 5,000 g / mol, preferably in the range of 500 to 3000 g / mol, measured for example by gel permeation chromatography (GPC). In one embodiment of the present invention, a mixture of alkoxylate (A), alkoxylate (B) and alkoxylate (C) is used which at 25 ° C. has a dynamic viscosity in the range from 100 to 100,000 mPas, preferably 100 to 10,000 mPas -s, more preferably 500 to 5,000 mPa-s, determined according to DIN 51550.

In one embodiment of the present invention, the process according to the invention is carried out as a tanning process, hereinafter also referred to as a tanning process according to the invention, preferably as a retanning process, hereinafter also referred to as a retanning process according to the invention.

The tanning process according to the invention is generally carried out by adding a mixture of alkoxylate (A) and alkoxylate (B) and optionally alkoxylate (C) in one portion or in several portions immediately before or else during the tanning step. The tanning process according to the invention is preferably carried out at a pH of 2.5 to 4, it being frequently observed that the pH increases by about 0.3 to three units during the performance of the tanning process according to the invention.

The tanning process according to the invention is generally carried out at temperatures of from 10 to 45.degree. C., preferably at from 20 to 30.degree. Has proven useful a duration of 10 minutes to 12 hours, preferably one to three hours. The tanning process according to the invention can be carried out in any conventional tanning vessel, for example by walking in barrels or in rotated drums. In one embodiment of the present invention, a total of 0.01 to 10 wt .-% of a mixture of alkoxylate (A) and alkoxylate (B) and optionally alkoxylate (C), based on the shaved weight, preferably 0.5 to 3 wt .-%.

In a variant of the tanning process according to the invention, a mixture of alkoxylate (A) and alkoxylate (B) and optionally alkoxylate (C) is used together with one or more conventional tanning agents, for example with chrome tanning agents, mineral tannins, syntans, polymer tanning agents or vegetable tanning agents, such as they are described, for example, in Ullmann's Encyclopedia of Industrial Chemistry, Volume A15, pages 259 to 282 and especially page 268 ff., 5th Edition, (1990), Verlag Chemie Weinheim. The weight ratio mixture of alkoxylate (A) and alkoxylate (B) and optionally alkoxylate (C): conventional tanning agent or sum of conventional tanning agents is suitably from 0.01: 1 to 100: 1. In an advantageous variant of the process according to the invention, only a few ppm of conventional tanning agent are added to a mixture of alkoxylate (A) and alkoxylate (B) and optionally alkoxylate (C). In a variant of the tanning process according to the invention, a mixture of alkoxylate (A) and alkoxylate (B) and optionally alkoxylate (C) is used together with one or more fatliquoring agents or olephilic components. In a variant of the tanning process according to the invention, a mixture of alkoxylate (A) and alkoxylate (B) and optionally alkoxylate (C) is added in one portion or in several portions before or during pre-tanning. An addition in the pimple is conceivable. To carry out the Nachgerbverfahrens invention is based on conventionally, ie, for example, with chrome tanning agents, mineral tannins, polymer tanning agents, aldehydes, syntans or resin tanning tanned semi-finished or inventively prepared as described above semifinished products. To carry out the Nachgerbverfahrens invention at least one mixture of alkoxylate (A) and alkoxylate (B) and optionally alkoxylate (C) act on semi-finished products, ie, treated with at least one mixture of alkoxylate (A) and alkoxylate (B) and optionally Alkoxylate (C).

The retanning process according to the invention can be carried out under otherwise customary conditions. It is convenient to choose one or more, i. 2 to 6 action steps and can rinse with water between the interaction steps. The temperature in the individual reaction steps is in each case from 5 to 60.degree. C., preferably from 20 to 45.degree. It is expedient to use one or more further agents customarily used during the retanning, for example fatliquors, polymer tanning agents and acrylate- and / or methacrylate-based fatliquoring agents, tanning agents based on vegetable tanning agents, fillers, leather dyes or emulsifiers.

Another object of the present invention are leather, obtainable by the novel process, also referred to as leather according to the invention. Leathers of the invention are characterized by the fact that they are particularly soft and have a very pleasant feel. Leathers according to the invention generally contain from about 10 ppm up to 4% by weight, based in each case on the shaved weight, of a mixture of alkoxylate (A) and alkoxylate (B) and optionally alkoxylate (C).

Leathers according to the invention are particularly suitable for the production of garments, for example jackets, trousers, belts or shoes. Leathers according to the invention are also well suited for the production of furniture or furniture parts, such as sofas, armchairs, chairs, and for the production of automotive interior parts, such as car seats, center consoles, door panels and dashboards. Another object of the present invention is therefore the use of inventive leather for the production of clothing, furniture, furniture parts and / or automotive interior parts.

Another object of the present invention are clothing, furniture, furniture parts and automotive interior parts, containing or manufactured from leather according to the invention.

The invention will be explained by working examples. working examples

The hydroxyl number was determined according to DIN 52340. Viscosity is always to be understood as meaning the dynamic viscosity, determined at 25 ° C. according to DIN 51550. I. Preparation of Mixtures of Alkoxylate (A) and Alkoxylate (B)

1.1 Preparation of Mixture 1 of Alkoxylate (A.1) and Alkoxylate (B.1)

24 g of melamine (a.1) together with 24 g of glycerol (b.1) were placed in a 300 ml steel autoclave and heated to 160 ° C. with stirring. At 160 ° C 192 g of ethylene oxide were added within 6 hours. The mixture was allowed to react for three hours until the pressure became constant. Then the reaction mixture was stirred for 60 minutes at 15 mbar and 160 ° C and thereby freed from volatile components. There were obtained 235 g of mixture 1 in the form of a yellowish low-viscosity liquid.

Analytical data:

Hydroxyl number: 489 mg KOH / g

Viscosity: 935 mPa-s I.2 Preparation of Mixture 2 of Alkoxylate (A.2) and Alkoxylate (B.2)

27.7 g of melamine (a.1) together with 18.5 g of D - (-) - sorbitol (b.2) were placed in a 300 ml steel autoclave and heated to 160 ° C. with stirring. At 160 ° C 194 g of ethylene oxide were added within 8 hours. The reaction was allowed to continue for two hours until the pressure became constant. Then the reaction mixture was stirred for 60 minutes at 15 mbar and 160 ° C and thereby freed from volatile components. There were obtained 235 g of mixture 2 in the form of a pale yellowish low-viscosity liquid. Analytical data:

Hydroxyl number: 472 mg KOH / g

Viscosity: 1591 mPa-s I.3 Preparation of Mixture 3 of Alkoxylate (A.3) and Alkoxylate (B.3)

19.9 g of melamine (a.1) together with 29.9 g of 2,3-toluenediamine (b.3) were placed in a 300 ml steel autoclave and heated to 160 ° C. with stirring. At 160 ° C 190.2 g of ethylene oxide were added within 9 hours. The reaction was allowed to continue for two hours until the pressure became constant. Then the reaction mixture was stirred for 60 minutes at 15 mbar and 160 ° C and thereby freed from volatile components. There were obtained 225 g of mixture 3 in the form of a dark brown liquid.

Analytical data:

Hydroxyl number: 486 mg KOH / g

Viscosity: 1899 mPa-s

II. Production of Leather According to the Invention Production of Upper Leather (General Prescription)

Data in% are always% by weight and refer to the shaved weight. The percentages in aqueous formulations always refer to the solids or active ingredient content, unless expressly stated otherwise.

As a comparative retanning agent V-NGM.3 a melamine-formaldehyde condensate was used.

A commercially available bovine wet blue (Packer, USA) was folded to a thickness of 1, 5 to 1, 8 mm. The core area was cut into three strips of 1700 g each. The strips were then mixed in a drum (50 l) and a liquor length of 200% (based on shaved weight) at intervals of 10 minutes with 1.5% by weight of sodium formate and 0.5% of sodium bicarbonate and 1% of a naphthalenesulfonic acid Formaldehyde condensation product, prepared according to US 5,186,846, example "Dispersant 1." After 70 minutes, the liquor was drained off and the strips were then distributed to separate walk-drums 1 to 3. Together with 100% water, the walking barrels became 1 to 3 at 25 ° to 35 ° C. with 8% product according to the invention mixture 1 or mixture 2 or comparative tanning agent V-NGM.3 according to Table 1. After a milling time of 20 minutes, 0.7% formic acid was metered in. For the determination of the light fastness and heat yellowing, two strips were cut and dried, light fastness was evaluated after exposure for 24 hours, and heat yellowing at 100 ° C. after 72 hours. 2% by weight of a 50% by weight (solids content) aqueous solution of dyes, the solids of which were composed as follows, were metered in on the remaining leather after 60 minutes:

70 parts by weight of dyestuff from EP-B 0 970 148, Example 2.18,

30 parts by weight Acid Brown 75 (iron complex), Color Index 1 .7.16

Then it was drummed in the barrel for another 30 minutes.

Subsequently, in 0.3 to 0.5% formic acid was acidified to a pH of 3.6 to 3.8 in several steps. After 20 minutes, the liquor was evaluated for wasting and drained. The leathers were washed with 200% water.

Thereafter, in 100% water (50 ° C.), 4% of a fatliquor according to WO 2003/023069, Example A was metered. After 20 minutes, the mixture was acidified to pH 3.8 with 1% formic acid. The leathers thus obtained were washed, dried, staked, treated in a vacuum dryer at 60 ° C. for 30 seconds and evaluated according to the test criteria specified in Table 1. The leathers L.1 and L.2 according to the invention and the comparison leather V-L.3 were obtained. The rating was based on a grading system from 1 (very good) to 5 (poor).

Table 1 :

Leather L.1 L.2 V-L.3

Product used (8%) Mixture 1 Mixture 2 V-NGM.3

Heat resistance 2 2 3

Lightfastness 2 2 3

Color depth 2 2 4

Fullness 2 2 2.5

Softness 2 2 3

Claims

claims

1 . Process for the production of leather, characterized in that semi-finished products or pelts in aqueous liquor are treated with a mixture of

2. The method according to claim 1, characterized in that alkoxylate (A) is selected from alkoxylates of triazines having at least two primary amino groups per molecule.

Process according to Claim 1 or 2, characterized in that alkoxylate (A) is selects from alkoxylates of at least one compound of general formula (I)

where R ^{1 is} selected from NH 2, C 1 -C 10 -alkyl and C ₆ -C 14 -aryl, unsubstituted or substituted by C 1 -C ₄ -alkyl.

Method according to one of claims 1 to 3, characterized in that alkoxylate (B) is selected from alkoxylates of at least one triol or triamine.

Method according to one of claims 1 to 3, characterized in that alkoxylate (B) is selected from alkoxylates of at least one sugar alcohol.

Process according to one of Claims 1 to 5, characterized in that alkoxylate (A) and alkoxylate (B) are selected independently from ethoxylates and ethoxylates in which up to 50% by weight of propylene oxide can be incorporated.

Method according to one of claims 1 to 6, characterized in that the treatment is carried out as retanning.

Method according to one of claims 1 to 7, characterized in that the mixture of alkoxylate (A) and alkoxylate (B) has a hydroxyl number in the range of 20 to 1000 mg KOH / g.

Method according to one of claims 1 to 8, characterized in that one additionally treated with (C) at least one alkoxylate of at least one primary C 1 -C 30 -alkanol.

10. The method according to any one of claims 1 to 9, characterized in that one uses alkoxylate (A) and alkoxylate (B) in a weight ratio in the range of 95: 5 to 5: 95.

1 1. Leather obtainable by a process according to any one of claims 1 to 10.

12. Use of leather according to claim 1 1 for the production of clothing, furniture, furniture parts and automotive interior parts.

13. Clothing, furniture, furniture parts and automotive interior parts, containing or made of leather according to claim 1 1.