HK1187081B - Non metal tanning - Google Patents

Description

Non-metal tanning

In the production of leather, the tanning process is of decisive importance for the properties and quality of the leather produced. Among the various tannages known in the art (i.e. mineral, vegetable and synthetic), chrome-based tanning is a conventional and widely used tanning mode that can be easily implemented on an industrial scale on the most diverse kinds of skins and hides, and provides tanned leather with satisfactory properties (such as high shrinkage temperature Ts, flexibility and suitability for subsequent processing, such as neutralization, retanning, fatliquoring, dyeing, finishing).

However, chrome-based tanning preparations and tanning are considered environmentally unfriendly and it is therefore desirable to provide other tanning methods.

In WO 02/50313a2 it is proposed to add certain laccase derived enzymes to the tanning bath with synthetic or vegetable tanning agents, followed by the addition of an oxidizing agent. However, this adds some other steps to tanning and, in addition, requires particularly precise control of the enzyme activity.

In WO 94/10345a1 a metal tanning process is described in which in a first step (a) a substrate is pretreated with certain compounds of formula (1) defined therein comprising two substituents selected from carboxyl and hydroxyl groups and defined reactive groups; and metal tanning is carried out in a second step (b). Pre-treatment (a) is carried out to improve tanning with a metal tanning agent in a subsequent step (b).

In the literature mentioned in the introduction to WO 94/10345a1, Evans et al, j.a.l.c.a., volume 82 (1987), pages 88-95, which involves pretreatment of certain collagen substrates with 1, 2-dicarboxylic acid and subsequent aluminum tanning, the treatment of lamb skins with 2-N- [ bis- (3',4' -dicarboxyphenyl) methyl ] methylamino-4, 6-dichloro-s-triazine followed by tanning with alkalized aluminum sulfate is described. Also in this document, a pre-treatment is done to improve the tanning with a metal tanning agent (alkalised aluminium sulphate) in the subsequent tanning step.

Some Crosslinking tests carried out on Collagen of denatured animal tendons (kangaroo tail tendon, KTT) with various Crosslinking compounds (which do not necessarily act as a complete tanning material per se) are described by j.h.bowes and c.w.cater in the literature "Crosslinking of Collagen", j.appl.chem., 15, 7.1965 to investigate its Crosslinking potential; the crosslinking compounds are, in particular, difluorodinitrodiphenyl sulfone, diisocyanates, various aldehydes (formaldehyde, glyoxal, malondialdehyde, succinaldehyde, glutaraldehyde, adipaldehyde, acrolein and dialdehyde starch), cyanuric chloride and various cyanuric chloride derivatives (methoxy derivatives, amino derivative hydrochlorides, sulfonate derivative sodium salts, 5-sulfonaphthalen-1-ylamino derivative sodium salts and bis-4, 4 '-diaminostilbene-2, 2' -disulfonic acid derivative sodium salts) which can be combined with conventional tanning materials to improve the resistance to deterioration due to moist heat and perspiration. Finally, their conclusions are drawn from their measurements: aldehydes (glutaraldehyde) appear to be the most promising because of stability and the number of crosslinks, while cyanuric chloride derivatives are less useful as crosslinkers in collagen.

It has now been surprisingly found that non-metallic tanning with excellent quality can be obtained using the tanning agents defined below (in particular even as fully tanned material) and tanning process, which also allows omitting the pickling conventionally carried out before chrome tanning or aldehyde tanning, unless it has to be carried out for other reasons such as degreasing. The present invention relates to a tanning process, a defined tanning agent composition, the use of the tanning agent and compositions thereof, tanned leather, skins or pelts and their use for further processing.

In this context, non-metallic tanning process means tanning that does not occur using any cationic metal compound having tanning activity, i.e. polyvalent metal compounds, mainly chromium, aluminum, iron, zirconium or titanium salts and the like. In this context, non-metal tanning agents are meant to be tanning agents which do not contain any tanning-active cationic metal compounds, i.e. polyvalent metal compounds, mainly chromium, aluminum, iron, zirconium or titanium salts and the like.

Hereinafter, alkyl refers to straight or branched chain alkyl groups unless otherwise specified.

The present invention therefore firstly provides a process for the manufacture of tanned leather, skins or pelts by non-metallic tanning, comprising the step of tanning a softened hide, skin or pelt in a tanning bath with a tanning agent (a) which is a dichlorodiazine comprising a sulpho group, selected from compounds of formula (I)

A compound of formula (II)

And a compound of formula (III)

And mixtures of two or more thereof,

wherein

R1 represents hydrogen, methyl, methoxy, benzoyl, naphthoyl, mono-or di (C)_1-4Alkyl) -aminocarbonyl, C_1-8Alkoxycarbonyl or oxy-mono-or oligo- (C)_2-3Alkyleneoxy) -carbonyl

R2-(SO₃M)_nRepresents a group of the formula

Or

R3 represents hydrogen, C_1-8Alkyl or C_1-8An alkoxy group,

m is a number of 1 or 2,

n is a number of 1 or 2,

and

m represents hydrogen or an alkali metal cation or an ammonium cation which is a protonated tertiary amine or quaternary ammonium cation;

the tanning bath has a pH of 6-10 at the beginning of the tanning step.

In formulae (I) and (II), the parenthesis included in the right hand portion of the bicyclic ring system is meant to indicate that the m sulfonic acid groups are attached to the corresponding number of carbon atoms of the benzo ring within the parenthesis, or/and to the remainder of said R1.

C_1-8Alkyl or C_1-8Alkoxy is preferably C_1-4Alkyl or C_1-4Alkoxy, more preferably ethyl or ethoxy, or most preferably methyl or methoxy. Alkoxy groups may also be oligomeric alkyleneoxy chains comprising from 2 to 10 alkyleneoxy units, preferably from 2 to 7 alkyleneoxy units, the alkylene units having 2, 3 or 4 carbon atoms.

The tanning agent (A) may consist of more than one compound of the formulae (I) and/or (II) and/or (III).

When M is an alkali metal cation or an ammonium cation, then it can be any of the alkali metal cations or ammonium cations commonly used to form salts in anionic compounds.

Preferably, the alkali metal cation is selected from lithium, sodium and potassium, more preferably, the alkali metal cation is sodium.

Preferably, the ammonium cation is a cation of formula (Ic):

wherein

R10, R11, R12 and R13 are the same or different and are each independently selected from H, C_1-4Alkyl radical, C_2-3Hydroxyalkyl and benzyl, provided that only one of the 4 substituents R10, R11, R12 and R13 may be H.

Preferably, the first and second electrodes are formed of a metal,

r10 is H or C_1-4Alkyl, and

r11, R12 and R13 are the same or different and are each independently selected from C_1-4Alkyl radical, C_2-3A hydroxyalkyl group; or

R10, R11, R12 and R13 are the same or different and are each independently C_1-4An alkyl group; or

R10, R11 and R12 are the same or different and are each independently C_1-4Alkyl or C_2-3Hydroxyalkyl radicals, and

r13 is benzyl.

More preferably, the ammonium cation is selected from: mono-hydrogen tri (C)_2-3Alkanolammonium, tetra (C)_1-4Alkyl) ammonium, tri (C)_1-4Alkyl) -mono (C)_2-3Alkanolammonium, di (C)_2-3Alkanol) -di (C)_1-4Alkyl) ammonium, mono (C)_1-4Alkyl) -tri (C)_2-3Alkanolammonium, monobenzyltris (C)_1-4Alkyl) ammonium and monobenzyltris (C)_2-3Alkanol) ammonium.

In particular, the ammonium cation is a quaternary ammonium cation.

More particularly preferably, M is an alkali metal cation, even more particularly preferably, M is sodium.

If in formula (I) or (II) R1 is hydrogen, methyl, methoxy, C_1-8-alkoxy-carbonyl or mono-or di (C)_1-4Alkyl) -aminocarbonyl, the compounds of formulae (I) and (II) more particularly the compounds of formulae (Ia1) and (IIa1)

Wherein R4 is hydrogen, methyl, methoxy, C_1-8-alkoxy-carbonyl or mono-or di (C)_1-4Alkyl) -aminocarbonyl.

If in formula (I) or (II) R1 is benzoyl or naphthoyl, the compounds of formulae (I) and (II) are more particularly those of the formula

Or

Or

Or

Wherein

m1 is 0 or 1 and

m2 is 0 or 1

Provided that m1+ m2 is 1 or 2.

If in formula (I) or (II) R1 is oxy-mono-or oligo- (C)_2-3Alkyleneoxy) -carbonyl, compounds of formula (I) or (II) and more particularly compounds of the formula

Wherein

q is 1 to 10, and

m3 is 0 or 1.

Preferably, the compound of formula (I) is a compound of formula (I-I):

preferably, the compound of formula (II) is a compound of formula (II-I):

preferably, the compound of formula (III) is a compound of formula (III-I):

wherein n is 1 or 2, more preferably 1.

More preferably, the compound of formula (III) is a compound of formula (III-II):

the compounds of the formulae (I) and (II) are known or can be prepared according to known methods, preferably by sulfonation of the compounds of the formula (IV) or of the respective compounds of the formula (V),

wherein

R5 represents hydrogen, methyl, methoxy, benzoyl, naphthoyl, mono-or di (C)_1-4Alkyl) -aminocarbonyl, C_1-8Alkoxy-carbonyl or hydroxy-Mono-or oligo- (C)_2-3Alkyleneoxy) -carbonyl

The compounds of the formula (III) are known or can be prepared according to known methods, preferably by sulfonation of the compounds of the formula (VI),

wherein R6 represents a group of the formula

Or

The sulfonation may be carried out under conditions conventional per se, for example with concentrated sulfuric acid (preferably at a concentration of 98% w/w) or oleum, at temperatures above 120 ℃ and preferably between 130 ℃ and 240 ℃ as appropriate to achieve the desired degree of sulfonation. Upon completion of the sulfonation reaction, the sulfonic acid produced may react with a base to form a salt.

The bases which can be used for the salification and the adjustment of the pH after completion of the sulfonation reaction are preferably selected from: alkali metal bases, quaternary ammonium hydroxides and carbonates.

The alkali metal base is preferably selected from: hydroxides, carbonates and bicarbonates of lithium, sodium and potassium and mixtures thereof.

The quaternary ammonium hydroxides and carbonates are preferably selected from: hydroxides and carbonates of tetramethylammonium, tetraethylammonium, and benzyltrimethylammonium.

The compounds of formula (I) and/or (II) may be used in salt form, preferably as alkali metal salts, more preferably as sodium salts, of sulphonic acids. The compounds of formula (I) and/or (II) in the form of salts are generally soluble in water and they are suitably used in the form of an aqueous solution or dispersion (at a higher concentration than the corresponding saturated solution concentration), preferably in an amount of from 2 to 70% by weight, more preferably from 10 to 50% by weight, wherein the% by weight is based on the total weight of the solution or dispersion of the compound of formula (I) and/or (II). Preferably, the solution or dispersion also comprises the above-mentioned dispersing agent (B) in the above-mentioned concentrations suitable for dispersing the compounds of formula (I) and/or (II) when the latter are added in the form of a dry product and stirred into the solution.

The surfactant (B) is preferably selected from:

(B1) a non-ionic surfactant, a surfactant,

(B2) an anionic surfactant, a surfactant,

(B3) an amphoteric surfactant, and

a mixture of two or more of them,

with the proviso that the surfactant (B) has no substituents, in particular no primary or secondary amino groups, which are capable of reacting with the compounds of the formula (II) under the selected reaction conditions. Preferred mixtures are mixtures of (B2) with (B1) and/or (B3) or mixtures of (B1) with (B3).

Preferably, the nonionic surfactant (B1) is selected from: oligo-or polyglycol ethers of aliphatic alcohols, oligo-or polyglycol esters of aliphatic carboxylic acids, alkoxylated fatty acid amides, and alkoxylated partial esters of glycerol or sorbitol with fatty acids.

Preferably, the alkoxylation of the fatty acid amides and of partial esters of glycerol or sorbitol with fatty acids leads to oligo-or polyglycol ether chains.

Preferably, any oligo-or polyglycol ether chain contains 2 to 60, more preferably 2 to 24 oxyalkylene units, said units being oxyethylene and optionally oxypropylene units, and preferably at least 40 mole%, more preferably at least 50 mole% being oxyethylene units, and preferably the non-ionic surfactant (B1) contains at least two oxyethylene units.

Preferably, the lipophilic aliphatic group of the aliphatic alcohols, aliphatic carboxylic acids, fatty acid amides and fatty acids comprises 8 to 24 carbon atoms. Aliphatic groups may be saturated or unsaturated (preferably containing only one double bond) and may be straight-chain or branched, with branching being preferred.

As examples of aliphatic alcohols, mention may be made of lauryl, cetyl, myristyl, stearyl or oleyl alcohol and C_9-15Oxo alcohols (oxoalcohols).

As examples of aliphatic carboxylic acids and fatty acid amides, mention may be made of lauric acid or amide, palmitic acid or amide, myristic acid or amide, stearic acid or amide, behenic acid or amide, arachidic acid or amide, oleic acid or amide.

Oligo-or polyglycol ethers of aliphatic alcohols can be prepared by oxyethylation and, if oxypropylene units are also present, by oxypropylation of the corresponding aliphatic alcohol.

Alkoxylated fatty acid amides can be prepared, for example, by oxyethylation and, if oxypropylene units are also present, by oxypropylation of the corresponding fatty acid amide, such as aliphatic acid diethanolamide or diisopropanolamide.

Oligo-or polyglycol esters and sorbitol monoesters can be prepared, for example, by esterification of the corresponding oligo-or poly-ethylene-and optionally-propylene-glycol ethers or sorbitol. The monoglycerides may be partial saponification products of the corresponding naturally occurring triglycerides.

Preferably, the anionic surfactant (B2) is selected from: anionic polycarboxylates, aliphatic fatty acids (soaps) in salt form, methyltaurates of aliphatic fatty acids and anionic derivatives of nonionic surfactants, preferably anionic derivatives of nonionic surfactants (B1), in particular carboxymethylated or carboxyethylated products of nonionic surfactants (B1), or sulfuric or phosphoric monoesters of nonionic surfactants (B1), in particular in alkali metal salt form.

Preferred anionic polycarboxylates are polyacrylates and polymethacrylates.

Preferably, the amphoteric surfactant (B3) is a betaine or sulphobetaine or anionic derivative of a cationic surfactant, which may be selected from: tertiary or preferably quaternary derivatives of fatty amines, e.g. having 8 to 24 carbon atoms in the fatty amine chain, and in which the substituent of the tertiary or quaternary amino group is C_1-4Alkyl (preferably methyl or ethyl) or hydroxy-C_1-4Alkyl groups, preferably ethanol or isopropanol, and optionally benzyl groups, and wherein, if desired, the tertiary amino groups or quaternary ammonium groups may also contain oligo-or polyglycol ether chains similar to those mentioned above in the nonionic surfactant (B1). As examples of fatty amines, mention may be made of laurylamine, cetylamine, myristylamine, stearylamine or oleylamine, and the amino group may be substituted by two methyl or ethyl groups and optionally a methyl or benzyl group, or by three methyl or ethyl groups or by two ethanol groups. If the tertiary or quaternary amino group is alkoxylated it may preferably comprise a total of 2 to 40, more preferably 2 to 24 alkyleneoxy groups, preferably at least 40 mole% being ethyleneoxy groups and the remainder being propyleneoxy groups. The tertiary amino groups preferably being protonated, e.g. with hydrochloric acid, phosphoric acid or C_2-20Alkanoic acid, preferably C_2-5The alkanoic acid is protonated. Anionic derivatives of these cationic surfactants are, for example, carboxymethylated or carboxyethylated products, sulfuric acid or sulfamic acid monoesters or phosphoric acid monoesters or diesters of those cationic surfactants which contain hydroxyl groups.

Preferably, the surfactant (B) is a nonionic surfactant (B1).

Preferably, a non-ionic surfactant (B1) is used, more preferably, the non-ionic surfactant (B1) is a compound of formula (VII) (polyglycol ether):

R7-O-(C_2-3alkylene-O)_r-H (VII)

Wherein

R7 represents C_8-24Alkyl or C_8-24An alkenyl group, which is a radical of an alkenyl group,

C_2-3alkylene is selected from-CH₂-CH₂-、-CH₂-CH(CH₃)-、-CH(CH₃)-CH₂-and combinations thereof, preferably selected from-CH₂-CH₂-、-CH₂-CH(CH₃) -and combinations thereof,

r represents a number of 2 to 60,

if the nonionic surfactant (B1) of the formula (VII) consists of more than one compound of the formula (VII), r can also be calculated and expressed as the average number of radicals of the formula (VII) in the mixture,

with the proviso that the compound of formula (VII) comprises at least two ethyleneoxy units and with the proviso that at least 40% of the total number of alkyleneoxy units in the compound of formula (VII) are ethyleneoxy.

The product may be dissolved or dispersed in water, if desired. If a dry product is desired, it can be obtained in a manner conventional per se from an aqueous solution or dispersion of the reaction product, for example by precipitation (for example by salting out) and filtration, or by evaporation under controlled conditions.

Tanning agent (a) comprising more than one compound of formula (I) and/or (II) and/or (III) may be prepared by physically mixing more than one compound of formula (I) and/or (II) and/or (III). Physical mixing can be done in dry form and/or in dissolved or dispersed form, preferably in dissolved or dispersed form in water.

The tanning agent (a) can be used as such, in the form of a preparation, preferably in dry form or more preferably in the form of an aqueous solution or dispersion.

According to a particular aspect of the invention, the tanning agent (a) is in the form of an aqueous composition (T) free of any metal-based compound having tanning activity, the aqueous composition (T) comprising the tanning agent (a) and water, and preferably comprising an additional surfactant (B).

Therefore, another subject of the present invention is the tanning process described above, and all the preferred embodiments thereof, in which the tanning agent (a) is used in the form of an aqueous composition (T) free of metal compounds having tanning activity.

More preferably, the composition (T) comprises from 2 to 70% by weight, in particular from 10 to 50% by weight, of the tanning agent (a), the% by weight being based on the total weight of the composition (T).

When a surfactant (B) is present in the composition (T), the weight ratio of surfactant (B) to tanning agent (a) in the composition (T) is preferably from 0.001 to 1, more preferably from 0.002 to 0.4, even more preferably from 0.005 to 0.1.

Preferably, in the composition (T), the surfactant (B) is a nonionic surfactant (B1). If an anionic or amphoteric surfactant (B2) or (B3) is used, the amount thereof is preferably 0.001 to 10 mol%, wherein the mol% is relative to the total molar amount of the tanning agent (a). More preferably, the surfactant (B) is only a nonionic surfactant (B1). If the surfactant (B2) is a polycarboxylate, its amount is preferably <5 wt.%, more preferably 0.01 to 4 wt.%, even more preferably 0.05 to 2 wt.%, wherein the wt.% is always based on the total weight of the tanning agent (a).

The composition (T) preferably has an acidic to neutral pH, more preferably it has an acidic pH. For adjusting the pH, a suitable buffer may be used, and thus the composition (T) preferably further comprises a buffer (C1) to maintain an acidic to neutral pH, preferably an acidic pH, more preferably a pH of 1 to 7, even more preferably a pH of 1 to 5.

The buffer (C1) is preferably selected from: potassium and/or sodium citrate, oxalate and phthalate, potassium and/or sodium monohydrogen and dihydrogen phosphate, mixtures of phosphoric acid with potassium and/or sodium dihydrogen phosphate, and mixtures thereof, preferably KH₂PO₄Or NaH₂PO₄With Na₂HPO₄Or K₂HPO₄Combinations of (a) and (b).

The amount of buffer (C1) in composition (T) is preferably selected so as to obtain the desired pH mentioned above. The amount of buffer (C1) is preferably 0.1 to 5% by weight, the% by weight being based on the total weight of composition (T).

The composition (T) may advantageously further comprise an agent (D) to protect against the damaging effects of microorganisms, preferably an agent (D) being a bacteriostatic additive and/or a microbicide, for example a fungicide.

As reagent (D), commercially available products can be used, which can be used in low concentrations, in particular in concentrations according to commercial recommendations. The amount of agent (D) in composition (T) is preferably from 0 to 10% by weight, more preferably from 0.01 to 10% by weight, even more preferably from 0.02 to 1% by weight, the% by weight being based on the total weight of composition (T).

According to a particular additional feature of the invention, the aqueous composition (T) may further comprise a polysaccharide-based thickener (E).

As thickener (E) products known per se can be used, in particular gums, carbohydrates, carbohydrate derivatives, such as pectins and hydrophilic cellulose derivatives, which form viscous solutions (colloidal solutions or true solutions) with water. Mention may be made of gums obtainable by fermentation and optionally chemical modification of natural plant exudates, such as xanthan gum, tragacanth gum, guar gum, carrageenan, alginate gum, agar gum, ulmus latifolia; and water-soluble carbohydrate derivatives, especially pectins, such as pectins and amylopectin (e.g. from corn starch or potato starch) obtained from fruits such as lemon fruit or apple, and hydroxyethyl cellulose. The gums, carbohydrates and carbohydrate derivatives may also be chemically modified, provided that they do not contain any substituents that are capable of reacting with the tanning agent (a) under the conditions of storage and use, in particular that they do not contain any basic amino groups, in particular do not contain any primary or secondary amino groups.

The thickener (E) can be used in the composition (T) in small portions, in particular enough to adjust the viscosity of (T) such that it is still flowable. When the thickener (E) is used in the composition (T), it is preferably added in a concentration such that the viscosity of the composition (T) is preferably 50,000 mPas or less, more preferably 200-10,000 mPas, even more preferably 300-2,500 mPas, particularly preferably 600-1,500 mPas at 20 ℃. The viscosity is Brookfield rotational viscosity, spindle 3, 20 rpm.

Preferably, the amount of thickener (E) in the composition (T) is from 0 to 5% by weight, more preferably from 0.1 to 5% by weight, said% by weight being based on the total weight of the composition (T).

A preferred composition (T) is composition (T1), which composition (T1) comprises, in addition to tanning agent (a), a surfactant (B) and/or a buffer (C1), more preferably surfactant (B) or surfactant (B) and buffer (C1); preferably, the composition (T1) further comprises an agent (D) and/or a thickener (E).

Therefore, another preferred embodiment of the present invention is the above tanning process and all its preferred embodiments, wherein composition (T) is an aqueous composition (T1) comprising tanning agent (a) and further comprising surfactant (B) and/or buffer (C1) to maintain acidic to neutral pH.

Therefore, another preferred embodiment of the present invention is the tanning process described above, and all its preferred embodiments, wherein composition (T) is an aqueous composition (T1) of tanning agent (a) comprising surfactant (B) and/or buffer (C)₁) And further comprising an agent (D) for protecting against the destructive action of microorganisms and/or a polysaccharide-based thickener (E).

Preferably, composition (T) is composition (T1) comprising:

2-70% by weight, preferably 10-50% by weight of tanning agent (a), said% by weight being based on the total weight of composition (T1);

a surfactant (B), wherein the weight ratio of surfactant (B) to tanning agent (a) is from 0.001 to 1, more preferably from 0.002 to 0.4, even more preferably from 0.005 to 0.1;

a buffer (C1) in an amount such that a pH of 1-7, more preferably a pH of 1-5 is obtained in the composition (T1), preferably the amount of buffer (C1) is 0.1-5% by weight, said% by weight being based on the total weight of the composition (T1);

0-10 wt.%, preferably 0.01-10 wt.%, more preferably 0.02-1 wt.% of agent (D), the wt.% being based on the total weight of composition (T1);

thickener (E) in an amount such that the viscosity of the composition (T1) at 20 ℃ (Brookfield rotational viscosity measured at 20rpm with spindle number 3) is 50,000 mPas or less, preferably 200-10,000 mPas, more preferably 300-2,500 mPas, even more preferably 600-1,500 mPas, in particular thickener (E) is used in an amount of 0-5 wt.%, more preferably 0.1-5 wt.%, based on the total weight of the composition (T1);

and the dry matter content of the composition (T1) is preferably from 4 to 75% by weight, more preferably from 10 to 60% by weight, the% by weight being based on the total weight of the composition (T1).

The dry matter content of (T) or (T1) can be estimated in a manner conventional per se, for example by calculation based on the reactants and components used-mostly by simply adding up the amounts of the respective substances added for the preparation of (T) or (T1) (in dry form) and subtracting any water formed during the reaction-or, preferably, by subtracting the amount of water determined in a conventional manner, for example by titration, such as Karl Fischer titration, from the total weight of (T) or (T1).

Particularly preferably, composition (T) or (T1) is composition (T2) which comprises thickener (E), preferably ≧ 0.1% by weight, more preferably 0.1% by weight to 5% by weight of (E), the% by weight being based on the total weight of composition (T2). The viscosity of the composition (T2) (Brookfield rotational viscosity measured at 20rpm with spindle No. 3) at 20 ℃ is preferably 300-2,500 mPas, more preferably 600-1,500 mPas.

The composition (T2) has satisfactory stability, is suitable for storage and transport and can be used directly. It can be easily diluted with water and can be directly metered into the tanning drum, if desired.

As substrate for the treatment with the tanning agent (a), in particular for tanning, it is possible to use any conventional animal hides, skins and pelts usually used for tanning, such as hides from cows, calves or buffalos (for example, also split hides), skins from goats, sheep or pigs, deer skins and pelts; and other hides and skins, for example from other mammals (foal, camel, alpaca, kangaroo, sandbag), reptiles (snakes, lizards), fish (sharks) or birds (ostrich), imitation sheepskins and pelts, may also be used in the process of the invention.

The bating substrate (animal hide, skin or pelt) can be processed in a conventional manner, i.e. edging, soaking, liming, deliming and bating, in a liming plant before tanning. Prior to deliming, the liminated hides, skins or pelts are usually fleshed, if desired, split and optionally cleaned, shaved, etc., and if desired degreased and/or unhaired.

The batched hides, skins and pelts to be used as substrates in the process of the invention can be prepared in a conventional manner in a liming plant, in particular by deliming and bating the liming substrate using reagents known for each of the mentioned process steps.

The deashing can be carried out in a conventional manner using known compounds such as acids, ammonium salts of low molecular weight aliphatic carboxylic acids, ammonium sulfate or sodium phosphate. Optionally, the deliming composition may comprise an enzyme, such as the enzymes mentioned below, so that softening and deliming may be at least partially combined, if desired.

For softening, known deproteinizing softeners can be used, especially in the form of softening compositions based on conventional proteolytic enzymes, mainly bacterial proteases, fungal proteases and pancreatin. Occasionally, other enzymes, such as lipases, amylases, and other hydrolases may also be used. Preferably pancreatin is used alone or in a mixture with other enzymes, such as lipases, amylases and other hydrolases. Commercial forms of such enzymes may be formulated with other components, particularly with some mineral carriers, sugars or polysaccharides and/or hydrotropes. For the purposes of the present invention, substrates which are generally softened with a pancreatin-based softening composition are very suitable.

The above softening compositions are particularly active in the weakly alkaline pH range, more particularly at alkaline pH ≦ 11, so that the pH of the softened substrate is preferably in the weakly alkaline range, especially at a pH of 7.5 to 11, more preferably 7.5 to 10.

In the case where the substrate has been delimed with an acid, it is also possible to use an acidic softener, such as pepsin, for example in the form of a 2% pepsin aqueous solution and having a pH of 3 to 4.

The tanning process of the invention is based on a true tanning using tanning agent (a) to obtain leathers, skins and pelts with true tanning properties, such as reduced or eliminated swelling, reduced deformability and increased hardness, reduced shrinkage by drying of volume, surface and thickness, increased porosity of the fibrous structure and further increased shrinkage temperature and firmness of the collagen fibres to hot water, without rotting.

The "step" in the tanning process according to the invention refers to any tanning step in the tanning process wherein the tanning agent (a) is allowed to act on the untanned or not fully tanned substrate, i.e. pre-tanning, main tanning or full tanning (also including combined tanning). Thus, the tanning agent (a) can be used for pre-tanning, for main tanning, or for full (i.e. full) tanning or for both pre-tanning and main tanning, as well as for combined tanning. However, the use of tanning agent (a) as a complete tanning agent or as both a pretanning agent and a main tanning agent is the most relevant aspect of the present invention.

The tanning process of the invention, which can be a one-step tanning (i.e. full tanning), or a two-step tanning (i.e. pre-tanning followed by main tanning), or a combined tanning, can be carried out directly after softening.

The tanning process using the tanning agent (a) of the invention can be carried out in aqueous, aqueous/organic or organic medium; suitable organic media include, for example, ethanol, isopropanol, acetone, methyl ethyl ketone, dimethyl sulfoxide, chloroform, chlorobenzene, and toluene. Preferably in a water bath, for example in a bath length (bath length) of 30-400 wt% water, preferably 40-200 wt%, most preferably 40-100 wt%, said wt% based on the total weight of the fleshed or (if the hide has been split) split substrate, and a temperature of preferably 10-50 ℃, more preferably 10-40 ℃, even more preferably 15-40 ℃. Preferably, the temperature at which tanning starts is 10-35℃, more preferably 15-30℃, and the temperature at the end is allowed to rise preferably by 5-20C, more preferably 8-15C, so that the final temperature reached is 20-40℃, preferably 25-40℃.

For the tanning process of the invention, the tanning agent (a) is added to the tanning bath in an effective concentration, preferably in a concentration of 0.5 to 20% by weight, more preferably 1 to 10% by weight, the% by weight being based on the weight of the fleshed or split substrate. The tanning agent (a) may be added in dry form or preferably in the form of an aqueous composition, preferably as mentioned above as composition (T).

Particularly preferred surfactants, in particular the surfactant (B) mentioned above, preferably a non-ionic surfactant (B1), and/or a buffer (C2) for an almost neutral to alkaline pH value, in particular a pH ≧ 6, may be added to the tanning bath in a weight ratio suitable for obtaining the desired pH at the start of the tanning step.

Therefore, another preferred aspect of the present invention is the above tanning process and all preferred embodiments thereof, wherein the tanning bath comprises a buffer (C2) to obtain an almost neutral to alkaline pH at the beginning of the tanning step.

As the buffer (C2), a known buffer can be used, which is preferably selected from: sodium and/or potassium bicarbonate, sodium and/or potassium carbonate, sodium and/or potassium hydrogen phosphate, sodium borate and tris. Preferably, the buffer (C2) is KH₂PO₄Or NaH₂PO₄And K₂HPO₄Or Na₂HPO₄Combinations of (a) and (b). Of particular advantage for the tanning process of the inventionThe above-mentioned compositions (T) are preferably used already containing the surfactant (B) and optionally also containing the agent (D) and/or the thickener (E). The buffer (C2) can be added directly to the tanning bath. Preferably a buffer (C2) is added to the two-step tanning to set the pH of the main tanning bath before the main tanning step. Composition (T), especially composition (T1), is particularly effective for tanning. The composition may contain some salts produced as a by-product from the sulfonation reaction followed by addition of a base.

The tanning process of the invention starts at a pH of 6 to 10, preferably 6 to 9, more preferably 6.5 to 8.5, in particular suitable for inducing the reaction of the tanning agent (a) with the substrate.

During tanning, the pH gradually and spontaneously drops by several pH units, especially 1-4 pH units, to an almost neutral to weakly acidic pH range, especially to a pH of 7-3.5, preferably 6.5-3.5. Thus, the method may be performed under self-adjusting pH conditions. If desired, however, the tanning reaction can be influenced by adding small portions of an acid (for example a mineral acid, such as sulfuric acid or phosphoric acid; or a low molecular weight carboxylic acid, for example a carboxylic acid having from 1 to 4 carbon atoms, preferably 1 or 2 carbon atoms, for example formic acid or acetic acid) or by adding, for example, small portions of a base (strong base), in order to accelerate or slow down the reaction and/or to shift the pH somewhat to a more neutral value.

In the method according to the invention, pickling is in principle not necessary and can be omitted for the most part. The subject of the present invention is therefore also the tanning process described above and all its preferred embodiments, in which the softened hides or skins or pelts are subjected to tanning with the tanning agent (a) without prior pickling.

However, if desired, pickling may be carried out, for example in order to obtain a certain compactness of the substrate or if the substrate is to be degreased under acidic conditions before tanning. The pickled substrate can be degreased in a conventional manner. Sometimes commercially available hides have been pickled. If the substrate has been pickled, the acid is suitably removed prior to tanning to obtain the desired pH of 6-10. Therefore, another subject of the present invention is the above tanning process and all its preferred embodiments, wherein the softened and pickled hides, skins or pelts are deacidified to a pH of 6-10 before tanning with tanning agent (a).

The deacidification can be carried out by using a corresponding mass of base for deacidification, suitably to obtain a pH value of 6 to 10, preferably 6 to 9. The deacidification can be carried out in a conventional manner using known compounds, such as sodium and/or potassium bicarbonate or/and sodium and/or potassium formate, and under conditions conventional per se, for example in a drum rotating for 60 minutes to 6 hours at a bath length of 50 to 400% by weight of water (said% by weight being based on the weight of the fleshed or (if the hide has been split) split substrate) and a temperature in the range of 10 to 30 ℃. If desired, the substrate may be kept in a deacidification bath, for example by standing overnight, optionally with intermittent drum rotation, for example for 5-15 minutes per hour, for example, in order to ensure that the deacidification is also carried out inside the substrate.

If the tanning process is started under almost neutral conditions, especially at a pH of 6-7.5-especially when using acid pickled and deacidified substrates-it is also possible to initially keep the pH in this range or to increase it by adding alkali to give a pH in the range of 6-9.

If (preferably) no acid pickling and deacidification is carried out, pre-tanning or full tanning can be carried out directly on the softened substrate. The pH at the start of the tanning process is preferably almost neutral to alkaline, especially in the range of 6.5-10, preferably 6.8-9; and gradually and spontaneously decreases several pH units during the treatment, especially 1-4 pH units to a nearly neutral to weakly acidic pH range, especially 7-4, preferably 6.5-4.5. The temperature is preferably in the range of 10 to 40 deg.C, more preferably 15 to 35 deg.C. More particularly, tanning is preferably started at 10-30 ℃, more preferably at 15-25 ℃ and at the end the temperature is allowed to rise by 5-20 degrees, preferably 8-15 degrees, to reach 20-40 ℃, preferably 25-40 ℃.

The tanning process of the invention is very simple and can be carried out in a relatively short time, in particular within about 5 to 24 hours, preferably within 6 to 12 hours.

After tanning, the spent tanning bath may be drained and the tanned leather, skin or pelt may be rinsed or washed, for example 1-3 times with water (e.g. 100-. Biocides, such as those mentioned above for (D), can also be added during the process, if desired, for example to the final wash bath, as preservatives for the resulting tanned hides, skins or pelts.

If desired, other non-mineral tanning agents (F) different from (a) having anionic or/and ethylenic unsaturation or/and containing basic groups can be applied before, after or together with tanning agent (a) in the pre-tanning, in the main tanning or in the full tanning, preferably for pre-tanning before the main tanning with (a) or in combination with (a) in the main tanning or full tanning, or/and preferably for supplementary tanning after the main tanning with (a) or full tanning, or even for retanning.

(F) Preferably selected from:

(F1) the plant tanning agent is prepared from a plant tanning agent,

(F2) a synthetic tanning agent is prepared by mixing a raw material,

(F3) synthetic, semi-synthetic or natural resins or polymers,

(F4) tanning natural oils or modified oils and, in particular,

(F5) a compound of formula (VIII)

Wherein

p is 1 or 2, and

m is as defined above with respect to the above,

(F6) tanned oxazolidines, in particular of formula (IX) or (X)

And

mixtures of two or more thereof.

As vegetable tanning agent (F1), known vegetable tanning agents can be used, in particular pyrogallol-or catechol-based tannins, such as oak cup, mimosa, teri, tara, oak, pine, sumac, quebracho and chestnut.

As syntan (F2), use may be made of known syntans, in particular syntans derived from sulfonated phenols and/or naphthols, and/or sulfones, or polymers of sulfones and/or sulfonated phenols and/or sulfonated naphthols with formaldehyde or acetaldehyde and optionally urea, with products based on sulfones being preferred.

As synthetic or semi-synthetic or natural resins or polymers (F3), it is possible to use, for example, the known polyacrylates, polymethacrylates, copolymers of maleic anhydride and styrene, condensation products of formaldehyde with melamine or dicyandiamide, lignins and natural powders (natural flours). Among synthetic or semi-synthetic or natural resins or polymers (F3), those having anionic character (such as polyacrylates, polymethacrylates, lignosulfonates and copolymers of maleic anhydride with styrene) and not containing basic amino groups are referred to herein as (F3-I).

As natural or modified oil (F4), use may be made of known natural triglycerides, such as rapeseed oil, fish oil or oxidized derivatives thereof, sulphated, sulphonated or oxy-sulphited fish oil or oxidized derivatives thereof or substitutes thereof.

As compound (F5), a compound in which p is 1 or 2, or a mixture of compounds in which p is 1 and p is 2, can be used.

Tanning with (a) can be carried out in the fully tanned form, or in the pre-tanned form before non-metal main tanning, which can be carried out with vegetable tanning agents or with syntans other than (a), such as (F) mentioned above, can also be carried out with tanning agent (a) of the invention, or in the main tanned form after non-metal or even non-mineral pre-tanning, which can be vegetable or synthetic, such as (F) mentioned above. When the tanning according to invention (a) is carried out in the form of main tanning after vegetable pre-tanning or synthetic pre-tanning with syntans, this pH-value can, if desired, be adjusted to the desired value of 6-10, for example by addition of alkali metal carbonates, bicarbonates or formates, for the tanning process according to the invention.

According to a particular feature of the invention, the tanning agent (a) can be used in combination with another non-mineral tanning agent (F), preferably (F-I), wherein (F-I) is selected from (F1), (F2) and (F3-I), for example in a weight ratio of (a) to (F-I) of 0.05:1 to 20:1, more preferably 2:1 to 10: 1. The concentration of the combined tanning agent may be required to achieve a certain tanning, e.g. 0.5-20 wt.%, preferably 1-10 wt.%, the wt.% being based on the weight of the fleshed substrate.

According to another particularly preferred characteristic of the invention, the substrate is subjected to a first tanning with (a) in one or two steps and then to a complementary tanning with a non-mineral tanning agent (F), preferably (F-II), (F-II) selected from (F1), (F2), (F3) and (F5). By complementary tanning, it is meant herein an additional tanning step carried out after main tanning or full tanning with (a), which does not substantially alter the characteristic class of the leather, skin or pelt tanned with (a), but which can improve some typical tanning properties. Typically, this is done with a smaller amount of supplementary tanning agent (F) than the amount of main or full tanning agent (a), preferably 5 to 80 wt.%, preferably 10 to 60 wt.% of (F), wherein wt.% is based on the weight of the amount of (a) used. Advantageously, this complementary tanning can be carried out after tanning with (a), under the temperature conditions mentioned above (for example 10-40 ℃), preferably under pH conditions for the bath length tanned with (a) (for example 40-200% by weight of water, said% by weight being based on the weight of the fleshed or (if the hide has been split) split substrate) and resulting from tanning with (a) (preferably after rinsing with water), which pH can generally range from 4 to 7.

The complementary tanning with (F), preferably with (F-II), can be carried out directly in the tannery after tanning, or even after rinsing, drying and optionally mechanical treatment of the tanned leathers, skins or pelts.

At the end of the tanning process, after draining the spent tanning bath or supplementing the tanning bath, the tanned leather, skins or pelts may, if desired, be treated with one or more conventional additives, such as one or more surfactants, preferably those mentioned above as (B), primarily (B1) or (B3), to protect the texture from damaging rubbing, or/and treated with preservatives, preferably those mentioned above as (D).

As mentioned above, the tanned leathers, skins or pelts prepared according to the invention can be further processed in a conventional manner, i.e. can be drained, dried and mechanically processed, typically for storage and/or transport.

According to another preferred feature of the invention, the substrate is subjected in one or two steps to (a) a first tanning, optionally subjected to a supplementary tanning with (F) or (F-II), and then to (F) a retanning.

Retanning with (F) can be carried out after rinsing, drying and optionally mechanical treatment of the tanned leather, skins or pelts, for example in a dyeing cabinet.

The process of the invention can be carried out in a very economical and simple manner, since the pickling and deacidification can be omitted and, in addition, the tanning itself can be carried out with a small amount of water and also without neutralization as otherwise conventionally carried out, for example after metal tanning.

By the process of the present invention, it is possible to obtain metal-free tanned leathers, skins or pelts (especially "wet-white" metal-free leathers) which have excellent properties, especially shrinkage temperature, softness and compactness, such as hard texture, and which have satisfactory fastness, especially when (a) or (T) are used for main tanning or full tanning, respectively. The "non-metallic white tanned" leathers, skins and pelts according to the invention, especially non-metallic "wet and white" leathers, can be obtained with high quality and very light self-color (i.e. almost white) if vegetable tanning agents are not used at all or if only white to light yellow vegetable tanning agents are used. When plant tanning agents of light brown to light red are also used, the hue of the resulting tanned leathers, skins and pelts is correspondingly slightly darker light brown or light red. Further elevated shrinkage temperatures Ts are obtainable when (a) is used for full tanning or for pre-tanning and main tanning followed by (F), especially (F-II) for complementary tanning.

The tanned leathers, skins and pelts prepared are suitable for further processing in conventional manner, mainly by retanning and/or fatliquoring and optionally dyeing and/or finishing. The fatliquoring may be carried out using known fatliquoring agents. Retanning is preferably carried out with (F). By retanning and fatliquoring them with (F), high quality crust leathers can be obtained on drying. For dyeing, known leather dyes (for example, those defined in "Colour Index by Society of Dyers and Colourists and synthetic Association of Textile Chemists and Colourists", and especially those listed) can be used, and dyeings having satisfactory properties, mainly Colour penetration, Colour yield and fastness, can be obtained. With those leathers, skins or pelts described above which have a very light self-color, i.e. almost white, it is also possible to obtain a dyeing effect of elegant shades (soft shades) with a very pleasant shade. If desired, the finishing can also be carried out using conventional leather finishes.

Therefore, another subject of the present invention is the use of the tanned leathers, skins or pelts produced according to the above process, and all the preferred embodiments thereof, for further processing by at least one other treatment selected from the group consisting of:

(a) retanning with other non-mineral tanning agents (F) than tanning agent (A),

(b) the fat is added into the mixture,

(c) dyeing, and

(d) and (6) finishing.

Preferably a and b and optionally c and/or d.

In the following examples, the percentages indicated are percentages by weight, unless otherwise indicated; the viscosity is the Brookfield rotational viscosity measured at 20 ℃ and 20rpm using a number 3 spindle.

Examples

Example 1

20g of 1, 4-dichlorophthalazine were charged to the reactor and heated to 230 ℃ with stirring. At this temperature, 15g of oleum were added over 15 minutes, the temperature was raised to 260 ℃ and stirring was continued at 240 ℃ and 250 ℃ for 5 hours, after which the mixture was cooled to 80 ℃. At this temperature, 80g of water and 30g of a 30% aqueous solution of sodium hydroxide were added, and the mixture was then cooled to 25 ℃.

A white-yellowish dispersion containing the compound of formula (1) (composition 1) was obtained.

Which is a mixture of compounds having the sulfo group in the 5-position and in the 6-position.

Example 2

5g 1-phenyl-4, 5-dichloro-6-pyridazinone were charged into a reactor and the product was heated to 160 ℃ with stirring. At this temperature, 2.5g of 98% sulfuric acid were added over 15 minutes to raise the temperature to 180 ℃ and stirring was continued at 170 ℃ and 190 ℃ for 5 hours, after which the mixture was cooled to 80 ℃. At this temperature, 20g of water and 4g of an 30% aqueous solution of sodium hydroxide were added, and the mixture was cooled to 25 ℃.

A white-yellowish dispersion containing the compound of formula (2) (composition 2) was obtained

Which is a mixture of compounds having the sulfo group in the 4-position and in the 2-position.

Example 3

1,000g of composition 1 obtained according to example 1 were set beforehand at 20-25 ℃ and 10.2g of disodium hydrogenphosphate, 8.7g of monosodium dihydrogenphosphate and 2.0g of disodium hydrogenphosphate were added with stirringBIT20 (1, 2-benzothiazolin-3-one based commercial biocide of Clariant, Switzerland). A white-pale yellow dispersion (composition 3) was obtained.

Example 4

100g of water are heated to 50-55 ℃. At this temperature, 4g of hydroxyethyl cellulose (2% solution of which has a viscosity of 5,500 mPas at 25 ℃ and pH 7.0) are added and stirring is continued for 1 hour. 104g of hydroxyethylcellulose solution are obtained.

1,000g of composition 3 obtained in example 3, previously set at 20-25 ℃, 103.8g of hydroxyethylcellulose solution are added with stirring. A white-pale yellow suspension with a viscosity of 1,250 mPa.s at 20 ℃ was obtained (composition 4).

Example 5

Example 3 was repeated, except that the same amount of composition 2 of example 2 was used instead of composition 1 of example 1. A white-yellowish dispersion (composition 5) was obtained.

Example 6

Example 4 was repeated, except that the same amount of composition 5 of example 5 was used instead of composition 3 of example 3. A white-yellowish suspension having a viscosity of 1,250 mPas at 20 ℃ was obtained (composition 6).

In the following application examples, the percentages indicated (unless otherwise indicated) refer to the weight of the split hides in application example B, to the weight of the fleshed hides in application examples Aa) and Ca), to the weight of the softened hides in application examples Ab) and Cb), and to the wet weight of the tanned leather in application example D. The shrinkage temperature Ts is measured according to the standard method IUP16/ISO 3380-. Where treatment is indicated as being carried out overnight, this is 10-12 hours. If not otherwise indicated, the pH is increased by addition of a 10% by weight aqueous solution of sodium formate (the% by weight being based on the weight of the solution), or decreased by addition of a 10% formic acid solution (the% by weight being based on the weight of the solution). The dye is in a commercially available form blended with sodium chloride, with a dye content of about 60%, "c.i." means "dye index".

Application example A

a) Deliming and softening:

the degummed and unskinned, ashed cow hides (french hides of the 8-12kg weight class) were loaded with water at 200%25 ℃, 0.1% degreaser (C ethoxylated with 7 moles of ethylene oxide per mole of alkanol)_12-15Alkanol) and 0.2% ammonium-based deliming agent (ammonium chloride and ammonium sulphate) and tumbling for 20 minutes. The bath was then drained and a fresh bath of 50%35 ℃ water, 0.1% of the above-mentioned degreasing agent and 0.5% of the above-mentioned ammonium-based deliming agent was loaded into the drum and the drum treatment was continued for 15 minutes. An additional 0.5% ammonium-based deliming agent and 0.8% 70% boric acid was added with 30% mixed organic acid (equal parts of adipic, glutaric and glutaric acids andsuccinic acid) and drum treated for 90 minutes. The pH was 7.8 and the cross section of the hide was colorless to phenolphthalein. Adding 0.6 percent of the mixtureBate PB1 p (Clariant, switzerland's pancreatin-based softener), and the drum treatment was continued for 30 minutes, after which the bath was drained. 300% water was added and the drum treated at 35 ℃ for 15 minutes, then the bath was drained.

b) Tanning:

a fresh bath of 50% water at 20 ℃ was added, measured and the pH adjusted to 8. 20% of composition 1 according to example 1 was added and tumbling was carried out for 60 minutes, after which the bath was heated to 30 ℃ over 120 minutes and tumbling was continued overnight at 30-35 ℃. The bath was then drained. 300% of water at 20 ℃ was added and the drum treatment was continued for 20 minutes.

If necessary, 0.2 percentWB (biocide of Bayer, germany) was added to the last 300% water.

The bath was then drained, the hide removed and hung on a horse.

The leather thus obtained was then homogenized, split and shaved to 1.0-1.1 mm.

Leather with satisfactory properties is obtained.

Application example B

a) Deliming and softening:

delipidated and split-skinned liminated cattle hides (french hides of the 8-12kg weight class) to a thickness of 2.4-2.5mm are loaded with water at 200%25 ℃, 0.1% degreaser (C ethoxylated with 7 moles of ethylene oxide per mole of alkanol)_12-15Alkanol) and 0.2% ammonium-based deliming agent (ammonium chloride and ammonium sulphate) and tumbling for 20 minutes. Then, the bath is drained and 50% of 35 ℃ water, 0.1% of the above-mentioned degreasing agent and 0.5% of the above-mentioned degreasing agent are addedA fresh bath of ammonium-based deliming agent was loaded into the drum and the drum treatment was continued for 15 minutes. An additional 0.5% ammonium based deliming agent and 0.8% of a mixture of 70% boric acid and 30% mixed organic acids (equal parts of adipic, glutaric and succinic acids) were added and tumbled for 90 minutes. The pH was 7.8 and the cross section of the hide was colorless to phenolphthalein. Adding 0.6% ofBate PB1 p (Clariant, switzerland's pancreatin-based softener), and the drum treatment was continued for 30 minutes, after which the bath was drained. 300% water was added and the drum treated at 35 ℃ for 15 minutes, then the bath was drained.

b) Tanning:

a fresh bath of 50% water at 20 ℃ was added at pH 8. 10% of composition 1 according to example 1 was added and the drum treatment was carried out for 60 minutes, after which the bath was heated to 30 ℃ over 120 minutes and the drum treatment was continued overnight at 30-35 ℃.

If necessary, 0.2% ofWB (biocide from Bayer, germany) was added to the last 300% water.

c) Supplementary tanning:

then 2% Tara (Tara) (a commercial vegetable tanning preparation, which is an aqueous composition of Tara (Caesalpinia Spinosa) pod extract at a concentration of 50% by weight, based on the weight of the composition) was added and the tumbling treatment was continued for 3 hours at 35 ℃. The bath was then drained. 300% of water at 20 ℃ was added and the drum treatment was continued for 30 minutes. The bath was then drained, the hide removed and hung on a horse. The leather thus obtained was then homogenized and shaved to 1.0-1.1 mm.

If necessary, 0.2 percentWB was added to the last 300% water.

Leather with satisfactory properties is obtained.

Application example C

a) Deliming and softening:

the delipidated and unskinned impregnated bovine hides (30kg weight scale spanish bovine hides) were loaded with water having a temperature of 200%25 ℃, 0.1% degreaser (C ethoxylated with 7 moles of ethylene oxide per mole of alkanol)_12-15Alkanol) and 0.2% ammonium-based deliming agent (ammonium chloride and ammonium sulphate) and tumbling for 20 minutes. The bath was then drained and a fresh bath of 50%35 ℃ water, 0.1% of the above-mentioned degreasing agent and 0.5% of the above-mentioned ammonium-based deliming agent was loaded into the drum and the drum treatment was continued for 15 minutes. An additional 0.5% ammonium based deliming agent and 0.8% of a mixture of 70% boric acid and 30% mixed organic acids (equal parts of adipic, glutaric and succinic acids) were added and tumbled for 90 minutes. The pH was 7.8 and the cross section of the hide was colorless to phenolphthalein. Adding 0.6% ofBate PB1 p and continued the tumbling for 30 minutes, after which the bath was drained. 300% water was added and the drum treated at 35 ℃ for 15 minutes, then the bath was drained.

b) Tanning:

a fresh bath of 50% water at 20 ℃ was added. The pH was measured and adjusted to 8. 15% of composition 3 according to example 3 was added and the drum treatment was carried out for 60 minutes, after which the bath was heated to 30 ℃, 1% of polyacrylate resin was added and the drum treatment was continued overnight at 30-35 ℃. The bath was then drained. 300% of water at 20 ℃ was added and the drum treatment was continued for 20 minutes.

If necessary, 0.2% ofWB was added to the last 300% water.

The bath was then drained, the hide removed and hung on a horse.

1% of a syntan based on the reaction of sulfomethylated dihydroxydiphenyl sulfone with formaldehyde was added for additional tanning and drum treatment was continued for 120 minutes before draining the bath. 300% of water at 20 ℃ is added and the drum treatment is continued for 30 minutes, after which the bath is drained and the leather is taken out and hung on horses. The leather thus obtained was then homogenized and shaved to 2.0-2.2 mm. Leather with satisfactory properties is obtained.

Application example D

The leather obtained in application example C was retanned, fatliquored and dyed as follows:

the leather is loaded into a tumbler, 200% of water at 25 ℃ is added, followed by 0.3% of a degreasing agent (C ethoxylated with 7 moles of ethylene oxide per mole of alkanol)_12-15Alkanol) the drum was started and tumbled for 20 minutes. 0.5% acetic acid was added at a dilution ratio of 1:10 and the tumbling was continued for 20 minutes. The pH was 4.5 and the leather section was greenish by testing with a bromocresol green indicator. The bath was drained. 100% water at 25 ℃ was added, followed by 1.6% fatliquoring agent (oxysulfided fish oil) and tumbling was continued for 20 minutes. 5% of a retanning syntan based on sulfomethylated dihydroxydiphenyl sulfone reacted with formaldehyde and 5% of a phenol syntan (reaction product of sulfonated phenol with formaldehyde and urea) were added and drum treated for 2 hours. The bath was left overnight and tumbled intermittently for 5 minutes every 1 hour, then 0.5% formic acid diluted 1:10 was added and tumbled for 20 minutes, then the bath was drained and the leather was washed with 200% water. The bath was drained. 100% of water at 50 ℃ was added, followed by 5% of fatliquoring agent (3.5% alkyl sulfosuccinate and 1.5% oxysulfided fish oil) and the tumbling was continued for 1 hour. After addition of 0.5% formic acid, the drum was treated for 20 minutes and then the bath was drained. The leather was rinsed with 200% water at 20 ℃ for 5 minutes. The bath was then drained. Add 50% water at 20 ℃ and 5% black dye c.i. acid black 210 and continue tumbling for 1 hour, then add 200% water at 50 ℃ and 1% formic acid and continue tumbling for 10 minutes, then add additional 1% formic acid and continue tumblingAfter 20 minutes, the bath was drained. 200% of water at 20 ℃ and 1.5% of the cationic surfactant 2- (8-heptadecenyl) -4, 5-dihydro-1, 3-bis (2-hydroxyethyl) -1H-imidazolium chloride were added and tumbled for 15 minutes, after which the bath was drained and the leather was removed. After 24 hours of standing, it was dried under vacuum at 60 ℃ for 2 minutes, dried, hung and pulled soft. A black dyed leather with satisfactory properties is obtained.

Brown dyed leather with satisfactory properties was obtained by using the 2% brown dye c.i. acid brown 237 instead of the 5% black dye c.i. acid black 210.

Similarly, the leather from application example C and the leather obtained according to each of application examples a and B were retanned, fatliquored and dyed according to the procedure described in application example D.

In the above application examples, satisfactory commercial grades of leather are obtained, in particular with satisfactory texture tightness, structural compactness (obtained, for example, from some typical properties such as tensile strength, tear load and resistance to seam tearing), softness, fastness and overall appearance. In the dyeing examples, further dyed leathers having satisfactory properties (especially hue, dye penetration and color yield and fastness of dyeing) were obtained.

Claims (18)

1. Process for manufacturing tanned leather, skins or pelts by non-metal tanning comprising the step of tanning a softened hide, skin or pelt in a tanning bath with a tanning agent (A) which is a dichlorodiazine comprising a sulpho group, selected from compounds of formula (I)

A compound of formula (II)

And a compound of formula (III)

And mixtures of two or more thereof,

wherein

R1 represents hydrogen, methyl, methoxy, benzoyl, naphthoyl, mono-or di (C)_1-4Alkyl) -aminocarbonyl, C_1-8Alkoxycarbonyl or oxy-mono-or oligo- (C)_2-3Alkyleneoxy) -carbonyl

R2-(SO₃M)_nRepresents a group of the formula

Or

R3 represents hydrogen, C_1-8Alkyl or C_1-8An alkoxy group,

m is a number of 1 or 2,

n is a number of 1 or 2,

and

m represents hydrogen, an alkali metal cation or an ammonium cation which is a protonated tertiary amine or quaternary ammonium cation;

the tanning bath has a pH of 6-10 at the beginning of the tanning step.

2. A tanning process according to claim 1, wherein the softened hides, skins or pelts are subjected to tanning with tanning agent (a) without prior pickling.

3. A process according to claim 1, wherein the softened and pickled hides, skins or pelts are deacidified to a pH of 6-10 before tanning with tanning agent (a).

4. A process according to any of claims 1 to 3, wherein the tanning agent (a) is used in the form of an aqueous composition (T) free of metal compounds having tanning activity.

5. The method according to claim 4, wherein the composition (T) is composition (T1), the composition (T1) further comprising a surfactant (B) and/or a buffer (C1) to maintain an acidic to neutral pH.

6. The method according to claim 5, wherein the composition (T1) further comprises an agent (D) to protect against the damaging effects of microorganisms and/or a polysaccharide based thickener (E).

7. The process according to claim 6, wherein the aqueous composition (T)₁) Comprises a thickener (E).

8. Process according to any one of claims 1 to 3, 6 and 7, wherein the tanning bath comprises a buffer (C2) to obtain an almost neutral to alkaline pH at the beginning of the tanning step.

9. A process for manufacturing non-metal tanned leather, skins or pelts according to any one of claims 1 to 3,5, 6 and 7 wherein the tanning step with tanning agent (A) is pre-tanning, main tanning or full tanning or pre-tanning and main tanning.

10. Process according to claim 9, wherein an additional non-mineral tanning agent (F) which is different from tanning agent (a) and has anionic and/or ethylenic unsaturation and/or contains basic groups is used in pre-tanning, in main tanning or in full tanning, either before, after or together with tanning agent (a), or in combination with tanning agent (a) in full tanning.

11. The process according to claim 10, wherein the non-mineral tanning agent (F) is selected from:

(F1) the plant tanning agent is prepared from a plant tanning agent,

(F2) a synthetic tanning agent is prepared by mixing a raw material,

(F3) synthetic, semi-synthetic or natural resins or polymers,

(F4) tanning natural oils or modified oils and, in particular,

(F5)4, 6-dichloro-1, 3, 5-triazin-2-ylaminophenyl-mono-or-disulfonic acid salts,

and

(F6) tanning oxazolidines.

12. A process according to claim 9, wherein the substrate is tanned with tanning agent (a) in main tanning or full tanning and then subjected to supplementary tanning with non-mineral tanning agent (F) as defined in claim 10 or 11.

13. A process according to claim 10, 11 or 12 wherein the non-mineral tanning agent (F) is used in a smaller amount compared to the amount of tanning agent (a).

14. Use of a tanning composition (T1) as defined in claim 5, 6 or 7 as tanning agent (a) in a tanning process as defined in any one of claims 1 to 13.

15. Use of tanned leather, skins or pelts manufactured according to the process as defined in any one of claims 1 to 13 for further processing by at least one further treatment selected from:

(a) retanning with a non-mineral tanning agent (F) as defined in claim 10 or 11, different from tanning agent (A) as defined in claim 1,

(b) the fat is added into the mixture,

(c) dyeing, and

(d) and (6) finishing.

16. Use of tanned leather, skins or pelts manufactured according to the method as defined in any one of claims 1 to 13 for further processing by further treatment comprising retanning with a non-mineral tanning agent (F) as defined in claim 10 or 11.

17. Use of tanned leather, skins or pelts manufactured according to the process defined in any one of claims 1 to 13 for further processing by further treatments comprising retanning with a non-mineral tanning agent (F) as defined in claim 10 or 11, fatliquoring and optionally dyeing and/or finishing.

18. Tanned leather, skins or pelts obtainable by a process according to any one of claims 1 to 13.