GB2220215A - Leather dyeing assistants - Google Patents

Description

2220215 PROCESS FOR TREATING LEATHER Case 150-5197 The invention relates

to a process for dyeing leather.

According to the invention, there is provided a process for dyeing leather comprising applying to the leather one or more anionic dyesin the Dresence of a compound of formula I R- -N-(-CHr)-q- N (R2)7-(R1-0)-dR3 R2)Z --(Rr-0)-C-R3 R2)-9-(Rj-0)7-R3 n-1 (D AQ n-1 in which R is CA-24alkyl, C$_24alkenyl or -CO-CO-24alkyl or -COC8-24alkenyl; R2 is a group of the formula -CH2-CH-01 116 nS R, is propylene or ethylene; 11 R3 is hydrogen or -S03M, -CH2COOMP -CO-R,-COOM or P03M2, in which R,, is C,-6alkylene, C2-6alkenylene or phenylene; m is hydrogen or a cation; r is 0, 1, 2 or 3; a, b and c are zero or an integer from 1 to 15, whereby (r x a)+b+c is zero or an integer from 1 to 3r + 6; (I) Case 150-5197 (rxd) + e + f = a number from 2 to 120 AQ is a colourless anion, q is 2 or 3; and n is 1, 2 or 3.

For the avoidance of doubt, where a symbol appears more than once in a formula, its significances are independent of each other unless indicated to the contrary. Further, in this Specification the numbers defining a range, are indicated in that range.

The compounds of formula I can be added in the protonatable form, that Is to say when nal. However they are preferably applied together with conventional acids, such as mineral acids (e.g. sulphuric acid, phosphoric acid or HCl) or low molecular weight carboxylic acids, such as those containing 1 to 4 carbon atoms (e.g. formic acid, acetic acid, oxalic acid, lactic acid, citric acid.

Preferred compounds of formula I are of formula la or lb 2) C -(C2 Hi-0);l(C3 H60)j2--R3 RI-N (Ia) 2)i-(C2 Hi-0)n1-(C3 H63) i-2;--R3 1 (C21140)Z-4(C3H6-0-)M3-R3 N- R' C3 Eg-N (CA60-)-n 3-R3 (R2)W-(C2H40)iw-(C3H6-())Z-SR3 (Ib) where RO is C16-22alkyl or C16-22alkenyl; R2 is as defined above; and v Case 150-5197 in formula Ia, M1 + M2 + nj + n2 = 20 to 50; and in formula Ib, M3 + M4 + ms + n3 + n4 + n5 - 20 to 50; provided the maximum number of styryl oxide units is not more than 3; and the maximum number of propylene oxide units is not more than 2.

Preferably in the compounds of formula Ia and Ib, R3 is R3"t where R300 is as defined below and M2, n2, M3, % and ns are zero.

Preferably M is M' where M' is hydrogen, NH4+ or a colourless alkali cation (preferably lithium, sodium or potassium). More preferably M is W' where W' is NH4+.

R3 is preferably R3t where R3f is -S03MY P03M2 or -CH2COOM; more preferably R3 is R311 where R3" is S03M. Most preferably R3 is R311t where R311f is -S03-NH44. Preferably r is r, where r' is 0, 1 or 2. Preferably q is 3.

Preferably the sum of -(r x a) + b + c is zero or an integer of from 1 to 3. More preferably the sum of (r x a) + b + c is zero.

Preferably (r x d) + e + f is from 5 to 60.

Preferably R, is ethylene or a mixture of ethylene and propylene groups. Preferably the amount of ethylene oxide groups in Rj-0 and R2 groups is 90 to 100 mol %.

The products of formula I can be used in the protonatable or quaternised form and may be used simply as such or as a mixture.

Products of formula I are preferably applied in an amount of 0.05 to 5%, more preferably 0.2 to 1% by weight based on the substrate treated.

The products of formula I are useful as assistants in the dyeing of leather and are particularly useful in improving the combinability of anionic dyestuffs of different affinities, to improve the levelness of resulting dyeings, to improve the single dye take-up of individual anionic dyes, whereby the Yet migration relation of the dyes (formation of flecks on drying) is not negatively affected and 1 h Case 150-5197 the hydrophilipitY of the leather so treated is increased.

Preferably the compounds of formula I are those in which n is 2 or 3. More preferably the compounds of 'formula I are those of formula I where n-1 that are quaternised with dimethyl sulphate or benzyl chloride.

Preferably R Is Rt where R' Is C,&-22alkyl or Cif-22alkenyl. a (or W) can be a single group or may be a mixture resulting from a technical mixture of fatty amines.

R, Is preferably k 1 where R.t Is ethylene, propylene, butylent, ethenylana or phenylene. Nor preferably R. is R." where R." is ethylene, ethenylene or phenylene.

Preferably In the compounds of formula Ia where b + c - 0 and in formula Ib, R' Is oleyl.

Preferably dyeing is carried out at 15 - 601C, more preferably 25 to 500C.

Preferably dyeing Is carried out at a pH of 3.5 - 9, more preferably 4-8, most preferably 5-8.

Preferably the dye concentration is from 0.05 to 10 Z by weight based on the leather substrate.

Compounds of formula I can be prepared( by known methods)by the reaction of 1 sole of a compound of formula III 9 R -(N -(CH2)q -)c -NHa (III) N with (r x a) + b + c moles of styrene oxides followed by (r x d) + a + f moles of propylene oxide and/or ethylene oxide mt-ionally followed by Case 150-5197 2 + r mole& of a compound (V) selected from HS04M, Cl-CH 2-COOM1 BOOC-R,- COON or (2 + r) mole& of P30s.'.' 2 The group BOOC-RO-COON referred to in the above reaction include derivatives thereof (e.g. a cyclic anhydride). The compounds V are preferably selected from HOOC-CH 2_ COOH, chloroacetic acid, phosphoric acid, polyphosphoric acid; sulphuric acid (preferably oleum) or aminosulphonic acid; preferably in the presence of an H- yielding base.

More preferably the compound V is arrinesulphonic acid.

The reactions can be carried out conventionally.

The reaction of ethylene oxide and propylene oxide Is preferably carried out in the presence of a catalyst, e.g. an alkali metal hydroxide - such as NaOH under a nitrogen atmosphere preferably at 140 - 1801C.

The reaction with a cyclic anhydride Is preferably carried out in the presence of a catalyst at 0 to BOOC preferably together with base.

The reaction with chloracetic acid is carried out at 45-80% optionally In the presence of an alkali metal hydroxide.

The reaction with PaOs is preferably carried out at 30-80C, preferably in the presence of water and/or a base.

The reaction of aminosulphonic acid Is preferably carried out In. the presence of urea (preferably in an amount 10 - 200 % by weight of aminosulphonic acid used) at temperatures of 75 to 1309C.

Case 150-5197 Quaternisation can be carried out using well known quaternisating agents for example dimethylsulphate, diethylsulphate or benzylchloride, more preferably dimethylsulphate or benzylchloride. Quaternisation is carried out preferably in a nitrogen atmosphere at a temperature of 60 to 1200C.

Any kind of tanned leather commonly used as a substrate for dyeing from aqueous media may be used in the process of the invention, particularly grain leather (e.g. nappa from sheep, goat or cow and box leather from calf or cow), suede leather (e.g. velours from sheep, goat or calf and hunting leather), split velours (e.g. from cow or calf skin), buckskin and nubuk leather; as well as wool-bearing skins and furs (e.g. fur- bearing suede leather). The leather may be been tanned by any usual tanning,method, iz particular vegetable, mineral, synthetic or combined tanning (e.g. chrome tanned, zirconyl tanned or aluminium. tanning). If desired, the leather may also be retanned and/or fatted; for retanning, any tanning agent conventionally employed for retanning, e.g. mineral, vegetable or synthetic tanning agents [e.g. chromium, zirconyl or aluminium derivatives, oak, quebracho or mimosa extract, aromatic syntanes, copolymers of (meth)acrylic acid compounds or urea/formaldehyde resins] may be used. Before dyeing, the leather may also be fatted, and for this purpose any conventional fatting agent may be employed, in particular those that are commonly applied from aqueous media, e.g. animal vegetable or mineral fats, oils, resins or waxes and their chemically modified derivatives, e.g. hydrogenation, oxidation, saponification or sulphonation products of animal and vegetable fats and oils or chlorination and/or sulphonation products of mineral fats or oils and synthetic fatting agent. By the term "sulphonation" is meant the introduction of a sulpho group including also the formation of a sulphato group (. "sulphating") and the introduction of a sulpho group by reaction with a sulphite or S02 ( "sulphiting). Such fatting agents are described e.g. in F. Stather, "Gerbereichemie und Gerbereitechnologie", Akademieverlag Berlin, 1967, 4th edition, in chapter 21 on pages 517 535. For fatting it is preferred to use fat liquor emulsions in which the fat liquor is

Case 150-5197 emulsified by means of an emulsifier and/or by chemical modification, are preferably used.

The emulsifiers used in the process of the invention may be non-ionic, anionic or cationic, depending on the fatting agent, and are also well known in the art. They are for example described in the above-mentioned Stather publication. If the leather is fatted before dyeing a non-ionic or more preferably an anionic fat-liquor (preferably wherein at least some of the fatting agent and/or the optionally present emulsifier contains a sulpho group and/or a carboxy group) is preferably used. The fatting agents and emulsifiers mentioned in the above Stather publication are incorporated herein by reference. Particularly worth mentioning are the saponification and/or sulphonation products of tallow, train oil, neat's foot oil, olive oil, castor oil, rape seed oil, linseed oil, coconut oil, wood oil, cottonseed oil, sesame oil, corn oil and Japanese tallow and their mixtures with non-modified fats or oils and/or with wool- fat, beeswax, ceresin, mineral oil or optionally sulphonated paraffins.

Leathers used may be of various thicknesses, for example very thin leathers such as bookbinders's leather or glove leather (nappa), leather of medium thickness such as shoe upper leather, garment leather and leather for handbags or also thick leathers such as shoe sole leather, furniture leather, leather for suitcases, for belts and for sport articles. Hair-bearing leathers and furs may also be used. After tanning and before dyeing, the pH of the leather is advantageously brought to a pH in the range 4 to 9 (the leather is "neutralized"); depending on the thickness of the leather and on the compactness of its fibrous structure. The pH chosen is generally as follows: for grain leather and thick leathers (such as nubuk) pH-values in the range of 4 to 6; for suede leathers, split velours and for very thin leathers, pH-values in the range of 5 to 9; for intermediate dried suede leathers and intermediate dried split velours, the pH-values in the range in. of 6 to 9. Preferably, however, the pH-range is kept at neutral to weakly acidic, more preferably within the range of 5.5 to 7. For the adjustment of the Case 150-5197 pH-value of the leather, conventional assistants may be employed; for tanned leather of acidic character the pH may be adjusted by addition of suitable bases, e.g. ammonia or ammonium bicarbonate or alkali metal salts of weak acids, e.g. sodium formate, sodium acetate, sodium bicarbonate, sodium carbonate or sodium bisulphite (of which sodium formate and ammonia are preferred). Sodium carbonate and bicarbonate may also be used as second bases for the exact adjustment of the pH-value of the leather. For retanning - in so far as a retanning is carried out - the pH is kept preferably in the range of 4 to 7.

The acid dyes used in a process according to the invention include all types of acid dyes and hydrosoluble sulpho group-containing sulphur dyes, including those that can be metallised. Very good results are obtained using azo dyes (optionally metallised) and/or sulphur dyes with the compounds of formula I. Preferred are the sulphur dyes that include the so called Bunte salts as defined e.g. in Venkataraman "The Chemistry of Synthetic Dyes". Vol. VII, 1974, Academic Press, in chapter II on pages 35-68, preferably those as defined and listed in the Colour Index under the headings 11Solubilized Sulphur Dyes" and "Condense Sulphur Dyes". They may be employed in the usual commercial forms.

Subsequent to the treatment with the acid dye or hydrosoluble sulpho group-containing sulphur dye, the leather is preferably after-treated in the dye-bath with an acid; for example with hydrochloric acid, acetic acid or preferably formic acid, at pH-values preferably in the range of 2. 5 5. The treated leather may then be washed or rinsed with water and, upon drying, finished in the usual way. If desired the dyed leather may be fatted, hydrophobized and/or finished with an elastic polymer film or a gloss topping. If desired the fatting step, in particular with sulphonation products of natural fats or oils, may also be carried out simultaneously with the dyeing with the acid dye or hydrosoluble sulphogroup-containing sulphur dye.

Case 150-5197 Leather treated according to the invention, particularly leathers of medium thickness or very thick leathers (i.e. having a thickness of 1.0 mm or more) can be dyed very well and with a high dyes yield. Good single dye dyeings can be produced and the dyeings have good fastness properties.

Leathers dyed as described above, especially leathers of medium thickness and very thick leathers (in particular those of a thickness of 1 mm or more), are penetration-dyed surprisingly well and in high yield and are of optimum fastness. They are, however, particularly suitable (in the wet or dry state) as substrates for further colouration processes in- particular dyeings or printings, advantageously with hydrosoluble leather dyes, in particular dye displaying a medium to high affinity for leather, and which may be of anionic or basic (including cationic) character.

Still further, according to the invention, there is provided a process for dyeing leather.comprising:

a) dyeing the leather with one or more acid dyes together with a compound of formula I in one dyebath; and b) overdyeing the leather with one or more anionic or basic dyes in a second dyebath.

Anionic dyes for overdyeing, include sulpho group-containing sulphur dyes suitable as dyes for leather and wool (mainly the ones as described above), azo dyes and metal complexes of azo dyes as defined in the Colour Index under the title Acid Dyes, Mordant Dyes, Solubilized and Condense Sulphur Dyes and optionally Direct Dyes. Anionic dyes include dyes with basic or cationic character in general any such dyes that are usually employed for the dyeing of leather (see also Colour Index: Basic Dyes) can be used. In particular metal complex dyes of high affinity may be used.. Of the dye classes mentioned for the over-dyeing of the leather hydrosoluble sulpho group-containing sulphur dyes and the hydrosoluble cationic dyes are Case 150-5197 preferred. The preferred cationic dyes are those generally used for dyeing leather especially metal complex dyes.

For the overdyeing of the penetration-dyed leather with anionic or basic dyes, aqueous solutions of the dyes (optionally in the presence of conventional dyeing assistants) may be applied to the leather by known methods e.g. by spraying or coating or preferably by a further exhaust dyeing in a corresponding dye bath. Overdyeing in such dye baths may be carried out under standard dyeing conditions for example with the concentrations in the range of 0.02 - 2 % of the wet weight of the substrate and dyeing temperatures in the range from room temperature (= 20C) to 70C, preferably in the range of from 40 to 60C. According to one aspect of the invention, the material overdyed is further overdyed with a hydrosoluble sulpho group-containing sulphur dye as described above. For the second overdyeing the dye concentration may also be higher than the concentration for the first overdyeing e.g. up to 4 % referred to the wet leather. However, with-concentrations in the range of 0.02 - 2 % very good results may be achieved.

According to a further aspect of the invention, the dyed substrates are after-treated with a cationic dyeing assistant (K) in the same bath in which the dyeing (or overdyeing) and any fatting has been carried out. The cationic dyeing assistants (K) may be any conventional hydrosoluble or hydrodispersible, essentially colourless dyeing-assistants employed in the dyeing of textiles or leather with hydrosoluble dyes. The cationic dyeing assistants (K) that come into consideration are mainly amino compounds and these may be quaternary ammonium compounds or also non- quaternised amines that form ammonium ions in aqueous, in particular acidic medium.

The amino compounds that are to be used as K comprise mainly aliphatic mono- or polyamines (e.g. polymethylenediamines with 2-6 methylene groups in the polymethylene bridge or polyalkylenepolyamines in which alkylene contains 2-4 carbon atoms and containing 3-6 amino groups, or cyclic amines) which may bear one or more C9-24- Case 150-5197 aliphatic hydrocarbon radicals and which optionally may be benzylated and/or alkylated with Cl-4alkyl radicals, e.g. as described in USP 4,220, 449 (= DE-A 25 08 242), USP 4,297,296 (= DOS 29 24 471) and GB Pat. Appl. 2,165,268 (=DOS 35 34 102); or basic nitrogen atom-containing reaction products of such mono- or polyamines with cyanamide, dicyanodiamide, guanidine, biguanide, epichlorohydrin, formaldehyde, dicarboxylic acids and/or methylolated nitrogen-compounds and optionally with alkylating agents or further reactants as described for example in USP 4,439,203 (= DE-A 32 16 913) and USP 4,645,511 (= DOS 34 46 284), in PCT application 81-2423, in EP 11 370 A2, the amino group containing guanyl compounds as described in British Patent 1,238,091 or aromatic amino compounds. The cationic compounds (K) may optionally be blended with conventional additives, in particular with non-ionic, preferably hydrophilic dispersing agents (in particular for the production of aqueous dispersions of corres pondingly dispersed amino compounds). Examples of such cationic dyeing assistant (K) are those identified in the above patent and patent applications or also'methylolated melamine, condensation products of di-(C1-2alkyl)amine with epichlorohydrin (0.9:1 to 5:4) and aminobenzoic acid benzylester (alcoholic solution).

Preferably, the aftertreatment assistants (K) used are those in which the fatty acid residue has less than 9 carbon atoms, more preferably no more than 7 carbon atoms; most preferably no more than 4 carbon atoms.

The polycationic aftertreatment assistants have a high density of charge and are preferably substantially free of long-chain non-ionic groups, more preferably free of long-chain fatty acid group and non-ionic hydrophilic groups, most preferably additionally free of glycol groups and polyglycol ethers.

The after-treatment of the dyeings with the cationic dyeing assistants (K) is carried out in the same bath as the dyeing and any optional afterdyeing, advantageously under acidic pH conditions, preferably at pH 3-5, more preferably at pH 4, in particular at pH Case 150-5197 3.3-4. Preferably dyeing assistant (K) is added to the dye bath when the liquor after the dyeing (if a fatting or fat-liquoring agen t has been used then after the addition of this fatting agent and, if an after- dyeing has been carried out then after after-dyeing) has been acidified to the above indicated pH-values. Preferred pH-values 3-4, in particular pH-values in the range of 3-3--4. The cationic after-treatment agent (K) is employed advantageously in a concentration of 0.1-2 X, preferably 0.2- 1 X, calculated as the cationic compound, based on the wet weight of the substrate. The after-treatment is carried out advantageously in the same temperature range as the dyeing, the optional fatting and any optional lowering of the pH-value by acid addition, preferably at 25-700C, in particular 35-55C for leather and 25-55C for hair-bearing skins.

1 Case 150-5197 The invention will now be illustrated by the following Examples in which all parts and percentages are by weight and all temperatures are in "C.

Example 1

267 Parts of oleylamine and 2.5 parts of sodium hydroxide are heated to 135C in a suitable vessel which is evacuated by a water jet pump and a nitrogen atmosphere is introduced. The reaction vessel is heated to 1WC and 1320 parts of ethyleneoxide is added over 8 hours. The reaction is cooled (still under a nitrogen atmosphere) to about 7VC and 388 parts of urea are added over 15 minutes, the mixture is stirred at this temperature for 15 minutes, whereby the temperatures rises to 1101C. 194 parts of aminosulphonic acid are added slowly and.stirred for 6 hours at 110C. The resulting product is a compound of formula la (C2H40-)i --- -S030- NH40+ I__1 ""'(C2 H4 0-)n 03G NH40 in which m + n = 30 and R, is oleyl.

(1a) This is then reacted over 30 minutes, with vigorous stirring, with 126 parts of dimethylsulphate in the same vessel under an atmosphere of nitrogen. The reaction mixture is then heated to 950C and is stirred at this temperatue for 6 hours.

Examples 2 to 19 Compounds of formula 2, in quaternised form R-1N (P2)a CH2CH20-i-(C3H10-),-b -'(R2)U-(CH2CH20)i-(C3H70-)d-R3 Case 150-5197 (2) in which (a + b), (m + n), (c + d) and R are defined in Table 2 below and R2 is -CH2-CH-01;16 nS can be made by a method analogous to Example 1.

In Table 1 below fatty' = fatty acid mixture of behenyl fatty acid and arachidyl fatty acid.

Table 1

Example

1 mole of Amine from which R, is derived (a+b) (c+d) 0 2 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 R3 yielding reactant (m+n) Quaternising Agent (moles) (moles) 2 3 4 5 6 7 8 9 10 11 12 13 14 16 17 18 19 Tallow fatty acid do. do. do.

Fattyl acid do.

do. do.

y-tallow fatty amino propyl amine do.

y-fattyl amino propylamine tallow fatty amine C189 C20t C22 fatty amine mix do. do.

oleylamine do.

do.

1 0 0 0 0 0 0 2 0 0 3 1 2 0 1 1 2 0 35 35 20 40 40 40 35 30 40 Amino sulphonic acid do. (2) P205 (1) Cl-CH2CO2H (2) Amino sulphonic acid (2) do. (2) do. (2) do. (2) do. (2) do. (3) do. (3) do. (2) do. (2) do. (2) do. (2) do. (2) do. (2) do. (2) Dimethyl sulphate (1) do. (1) do. (1) do. (1) none Dimethyl sulphate (1) none Benzyl chloride (1) Dimethyl sulphate (1) tn do. (2) do. (2) do. (1) none 1 dimethyl sulphate (1) 0 do. (1) 0 W none (D Dimethyl sulphate (1) do. (1) Iin C) 1 t-11 -A -j Case 150-5197 In Example 5, the chloroacetic acid is added in the absence of urea but in the presence of an equivalent amount of NaOH at 500C.

In Example 4, P205 is added in the absence of urea at 450C, followed by the addition of an equivalent amount of NaOH to cause the carboxy and phosphoric acid partial ester groups to be in sodium salt form.

Examples 20 to 26 Compounds of formula 3, in quaternised form Rr-N-CA6 C2R4OM-(C3H70),-R3 (C2H40)n-(C3H70)d-R3 (R2)&(C2H40)o-(C3H70)b-R3 in which a, (b + c + d) (m + n + o) and h are defined below, and where R2 is -CH2-CH-0- 6H5 can be prepared by a method analogous to that of Example I.

Table 2

Example

21 22 23 24 26 1 mole of Amine from which R, is derived N-(y-aminopropyl)N-(y-tallow fatty amino propyl)-amine (a) 1 1 0 0 1 0 0 (b+c+d) 0 (m+n+o) R3 yielding reactant Amino sulphonic acid (2) N-(y-aminopropyl)-Ntallow fatty amine do. do.

1 N-(y-aminopropyl)-N- (MiX- Of C18-v C209 C22) fatty amine do.

do.

Quaternising Agent moles dimethyl sulphate (1) 0 0 0 0 0 0 20 do. (3) do. (2) do. (2) do. (3) do. (2) do. (3) do. (1) do. (1) benzylchloride (2) dimethyl sulphate (1) do.

none Case 150-5197 In the Application Examples, all percentages given are by weight of the leather treated.

Application Example A A degreased, tanned and neutralised sheep-nappa leather (for clothing) is treated in a vessel for 30 minutes with 200 % water, 0.5 % of the compound of formula la (example 1) and 0.5 % ammonia, 4 % of C.I. Acid Brown 432 is added and the leather is so treated for a further 30 minutes, after which 2 % of a commercially available leather fat liquor and 5 % of sperm oil sulphonate (sodium salt, 50 sulphonation) are added and the leather is treated for a further 60 minutes. Finally 1 of formic acid (85 %) is added and after 10 minutes a further 1 of formic acid is added and is so treated for a further 10 minutes. The bath is then drained off, the leather is washed at 25C with 300 % water and then appropriately fin ished. A level, well penetrated dyeing is produced.

Application Example B Chrome-split velours leather (1.3 to 1.4 mm with speckled effect) is treated in a vessel containing 800 % water at SOOC, 2 ammonia (25 X) and 0.5 % of a 35 % commercial preparation of di-tert.amylphenyldecaglycolether for 60 minutes. The bath is then drained and the leather is treated in a bath at 500C of 600 % water, 2 % ammonia (25 %), 2 % of a leather fat liquor and 0.5 % of the compound of formula la for 10 minutes. 3 % of C.I. Acid Red 88 (available as a commmercial preparation) are added, the leather is dyed for about 75 minutes and then 1.5 % of formic acid (85 X) is. added and treated for 30 minutes. The leather is then after-treated conventionally, hung dried and conditioned. A level red dyeing results.

Application Example C Chrome-tanned cow leather of 2.2 mm thickness is adjusted to pH 4.5 to 5. 5 in 150 % water with 0.5 % sodium formate and 0.8 % Case 150-5197 sodium bicarbonate and the bath is then drained off. For retanning, 150 % water, 4 % Tergotan LR (a polymethacrylate resin), 3 % of mimosa extract and 1 % of di-(sulphonaphthyl)-methane (a dispersing agent) are added. Retanning is continued for 40 minutes at 35C. The bath is then drained off and the leather is fatted with 150 % water and 10 % fatting substances (7.5 % sulphited fish oil, 2 % sulphated coconut oil and 0.5 % neat's foot oil) for 90 minutes, then acidified with 1 % formic acid and treated for a further 30 minutes under these conditions. The bath is drained and the leather is dyed with 150 % water, 1.8 % C.I. Solubilised Sulphur Black 1 and 2 % of the compound of formula la (Example 1) - in liquid form with 50 % actives at 25C for 120 minutes whereby a full penetration is achieved. After adding 100 % water and then 3 % formic acid (85 % concentration) gradually, the treatment is continued a further 60 minutes at 500C. The bath is then drained off and the leather is washed with 300 % water for 5 minutes at 501C.

The leather is hung-dried and cured conventionally. It is dyed to full penetration in a regular black shade.

Application Example D The procedure of Application Example A is followed up to the 5 minute washings with 300 % water. The bath is then drained off and the leather is dyed with 200 % water and 0.5 % of the dye of Example 35a of EP 92520 A2 for 20 minutes at 506C. The leather is then rinsed, dried and cured conventionally.

The resultant leather is dyed to full penetration in black and overdyed in black and has very good fastness.

t

Claims (13)

1. CLAIMS: -

   Case 150-5197/ UK 1. A process for dyeing leathercomprising, applying to the leather one or more anionic dyes in the presence of a compound of formula I t N-(CH2)q (R2)i-(R1-0)r-R3 r R2)-c-(Rr-0)-e-R3 (R2 Yb- (R-j j, 0)7-R3 n-1 (D AE) n-1 in which R is C8-24alkyl, C&-24alkenyl or -CO-C#_24alkyl or -CO-CA- 24alkenyl; R2 is a group of the formula -CR2 H-0- 16H5 R, is propylene or ethylene; R3 is hydrogen or -S03M, -CH2-COOMP -CO-R.-COOM or POA2. in which R. is a C,-6alkylene, C2-6alkenylene or phenylene; H is hydrogen or a cation; r is 0, 1, 2 or 3; a, b and c are zero or an integer from 1 to 15, whereby (r x a)+b+c is zero or an Integer from 1 to 3r + 6; (rxd) + e + f = a number from 2 to 120 AE) is a colourless anion, q is 2 or 3; and n is 1, 2 or 3.
2. 2. A process according to Claim 1, in which the compound of formula I isa compound of formula Ia or Ib ;,,Aj-(C2Hr-0).1 (C3Hj0)-xT-R3 R' N R)g-(C2HT--0)nr--(C3H.70)-,-T--R3 (I) (Ia) Case 150-5197/UK R'--- N - C3H6 -- N / G2H40m4- G3H7-0)M3-R3 \ \ (C2H40)n-I(C3H70-)-n3 -R3 (R2) a-(C2 H4 0) in 5 (C3 H7 -0) n 5 - R3 in which R' is C16-22alkyl or C16-22alkenyl R2 is as defined in Claim 1; and (Ib) in formula Ia, M1 + M2 + nj + n2 = 20 to 50 provided M2 + n2 is no greater than 2; and in formula Ib, M3 + M4 + ms + n3 + n4 + ns = 20 to 50, provided that a is no greater than 3; and M3 + n3 + ns is no greater than 2.
3. 3. - A process according to Claim 1 or Claim 2, in which R3 is R3F where R3t is S03MY P03M or -CH2COOM where M is as defined in Claim 1.
4. 4. A process according to Claim 3, in which R3 is R311 F where R3lyt is S03NH4 and %, n2, M3, n3 and ns are zero.
5. 5. A process according to any one of the preceding claims, in which r is r' where r, is 0, 1 or 2.
6. 6. A process according to any one of the preceding claims, in which (r x a) + b + c is zero or an integer from 1 to 3.
7. 7. A process according to any one of the preceding claims in which (r x d) + e + f is from 5 to 60.
8. 8. A process according to Claim 1, in which R, is ethylene or a mixture of ethylene and propylene.

   4.1 Case 150-5197/UK
9. 9. A process according to Claim 1, in which n is 2 or 3.
10. 10. A process according to Claim 1, in which R is R' where R, is C1622alkyl or C16-22alkenyl.
11. 11. A process for dyeing leather comprising:

    a) dyeing the leather with one or more acid dyes together with a compound of formula I defined in Claim 1 in one dyestuff; b) overdyeing the leather with one or more anionic dyes in a second dyebath.
12. 12. A process, substantially as herein described with reference to any one of Examples 1 to 26.
13. 13. Leather when treated with a process according to any one of the preceding claims.

    3700/DM/KC Published 1989 atThe PatentOffice, StateHcruBe. 6671 EUghHcIbornLondonWClR 4TP. Furtner c)PIes maybe obtainedfrom. The PatantOffioe. Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex tacbniclue. ltd, St Mary Cray Kent, Con. 1/87