FR2601050A1 - SLICED DYEING PROCESS FOR TANNED LEATHER - Google Patents

Abstract

THE INVENTION CONCERNS THE USE OF RETANNING AGENTS AS AUXILIARIES FOR THE SLICED DYES, IN AQUEOUS MEDIUM, OF TANNED LEATHER WITH A BASIC DYE AND POSSIBLE ANIONIC DYE.

Description

The subject of the present invention is a process for trenching dyeing of leather.

tanned with dyes

  basic in the presence of certain dye auxiliaries.

  In particular, the invention relates to a method of dyeing tanned leather, method according to which the leather is dyed in an aqueous medium with a basic dye (B), a retanning agent (H)

  being used as a dye aid.

  In the process of the invention, any kind of tanned leather can be used, usually used as a substrate for dyeing in an aqueous medium, in particular full-grain leather, such as nappa sheep, nappa goat, nappa cowhide , the boxcalf and the cowhide box, the suede leather like the sheep 15 suede, the goat suede, the suede calf and hunting, the suede crust for example of cow or calf, suede and nubuk, as well as woolen skins and furs, for example suede skins. The leather may have been tanned by any usual tanning method, in particular vegetable, mineral, synthetic or combined tanned, for example tanned with chromium, zirconium or aluminum or tanned semi-chrome. If desired, retanned and / or nourished leather can also be used; in particular, one can use leather retanned with any tanning agent commonly used for tanning, for example mineral, vegetable or synthetic tanning agents, such as chromium, zirconium or aluminum derivatives , extracts of oak, quebracho, chestnut or mimosa, aromatic syntanes, polyurethanes, polymers and copolymers of acrylic or methacrylic acid or melamine, dicyanodiamide and / or urea / formaldehyde resins. the invention, it is advantageous to use leather retanned with any usual retanning agent, preferably

  with a vegetable or synthetic retanning agent.

  Leather, in particular chrome tanned leather, is preferably retanned with up to 25% by weight,

  more preferably from 2 to 20% by weight of retanning agent, relative to the weight of tanned hides, in the wet state.

  Before dyeing according to the process of the invention, the leather may also have been fed with conventional food agents of anionic, cationic, nonionic or combined nature, in particular those usually used in an aqueous medium such as fats, oils, animal, vegetable or mineral resins or waxes and their chemical modification products, for example the hydrogenation, oxidation, saponification or sulfonation products of animal or vegetable fats or oils or the chlorination and / or sulfonation of fats or mineral oils, and synthetic food agents, for example esters

  polybasic acids, in particular phosphoric acid, with fatty alcohols which may be ethoxylated.

  By the term "sulfonation" is generally meant the introduction of a sulfo group, including the formation of a sulfate group (sulfation) and the introduction of a sulfo group by reaction with a sulfite or SO2 ( sulfitation). Such food agents are described in part for example in "Gerbereichemie 30 und Gerbereitechnologie" by F. Stather, Akademieverlag

  Berlin, 1967, 4th edition, chapter 21, pages 517-535.

260 1050

  For food, emulsions of food oils are preferably used in which the oil

  food is emulsified using an emulsifier and / or by chemical modification. According to.

  nature of the food agent, the emulsifiers can be nonionic, anionic or cationic; such emulsifiers are known and are described in part, for example, in the work by Stather mentioned above. When the leather is fed before the dyeing process of the invention, preferably a nonionic or better anionic food oil is used, preferably a food oil in which at least part of the food agent and / or the emulsifier optionally present contain a sulfo and / or carboxy group. The food agents and the emulsifiers mentioned in the work by Stather cited above are incorporated into the present application for reference. As food agents, special mention should be made of the saponification and / or sulfonation products of tallow, cod liver oil, beef foot oil, olive oil, castor oil, rapeseed oil, linseed oil, coconut oil, wood oil, cottonseed oil, sesame oil, l oil of Japanese corn and tallow, and their mixtures with unmodified fats or oils and / or with grease, wax

  bees, ceresin, mineral oil or possibly sulfonated paraffins.

  The leather used in the process of the invention may have different thicknesses. This is how very fine leathers such as leathers or glove (nappa) leathers can be used, leathers of medium thickness such as leathers for shoe uppers, clothing and leather goods, and thick leathers such as leather for shoe soles, furniture, travel goods, belts and sporting goods; woolen skins and furs can also be used. After tanning and before the dyeing process of the invention, the leather pH is advantageously adjusted to values from 4 to 8 (the leather is "neutralized"), the optimum pH range being chosen according to the thickness of the leather and the compactness of its fibrous structure. Thus, for full-grain leathers and thick leathers such as nubuk, the pH values are of the order of 4 to 6; for velvet leathers, velvet crusts and very fine leathers, the pH values are of the order of 4.5 to 6.5; for intermediate-dried velvet leathers and intermediate-dried velvet crusts, the pH values can be of the order of 5 to 6.5. The pH range 20 is preferably maintained at neutral to weakly acidic values, more preferably at pH values of the order of 4.5 to 6. To adjust the pH value of the leather, products can be used usual auxiliaries; for tanned leather with an acidic character, the pH 25 can be adjusted by adding appropriate bases such as ammonia, ammonium bicarbonate or the alkali metal salts of weak acids such as sodium formate, acetate of sodium, sodium bicarbonate, sodium carbonate, sodium bisulfite or buffer salts, for example mono-salts or alkali metal di-salts of polybasic acids,

  in particular phosphoric acid, for example sodium or disodium hydrogen phosphate or hydrogen-

  mono-potassium or di-potassium phosphate, preferably sodium formate and ammonium bicarbonate.

  Sodium bicarbonate and buffering salts can be used as a second base to precisely adjust the pH of the surface layers of the leather. For any retanning step, the pH is maintained at

  preferably values of the order of 4 to 6.5.

  If desired, the mineral tanned leather can also be masked, for example with an alkali metal formate, oxalate or polyphosphate or for example

  with double potassium and titanium oxalate.

  When the leather is retanned and / or fed, the strict maintenance of the sequence of stages: neutralization and retanning, or of the sequence of stages: food and dyeing, is not essential. For example, the food can be carried out in one or more stages and can take place before and / or after dyeing; retanning can for example

  also include further neutralization and / or masking, depending on the retanning agent used.

  In the process of the invention, it is also possible to feed the tanned hides, in the wet state. In this case, at least one feeding step is advantageously carried out after the

  dyeing; for this purpose, the food agents mentioned above can be used.

  The retanning agent (H) used as a dyeing aid according to the invention, in particular as a penetration aid, can be any usual substance, preferably anionic, used as main substance and / or preferably as

  auxiliary substance for the retanning of tanned leather.

  These substances are described for example in "Bibliothek des Leders", vol. 3 ("Gerbmittel, Gerbung und Nachgerbung"), ed. by Hans Herfeld, or in "Journal of the Society of Leather Technologists and Chemists", vol. 64, page 16 and following in

  Samir Das Gubta's article "Some thoughts on standar5 disation of synthetic tanning materials". The retanning agents (H) to be used as dyeing auxiliaries according to the invention are preferably semi-synthetic or synthetic.

  As semi-synthetic retanning agents, mention may be made of lignin sulfonates and their salts (sodium, chromium and / or calcium salts), and the polypeptides, for example degradation products of copper fibers, containing

  possibly a mineral tanning agent, in particular a chrome tanning agent.

  As purely synthetic retanning agents, there may be mentioned the aromatic syntanes, preferably the sulfonated oligophenylenes or the derivatives containing sulfo groups, naphthalene and / or phenol which optionally contain methylene, sulfonyl or ether bridges, in particular the condensation products of a sulfonic acid of diphenyl ether, the condensation products of a sulfonapthalene with formaldehyde, the condensation products of dihydroxydiphenylenesulfone with formaldehyde and with another compound containing sulfo groups, preferably the 5-sulfonaphthalene or a sulfonic acid of a diaryl ether (mainly a disulfonic acid of diphenyl ether), the condensation products of disulfodiaryl ethers with formaldehyde or the condensation products of oligophenylenesulfonic acid with formaldehyde . These products are preferably in the form of salts, in particular salts of alkali metals, alkaline earth metals and optionally

  also chromium salts (chromium syntans).

  The above products can be used alone or also in the form of mixtures of the various substances mentioned. In mixtures, the sulfonated lignins and their salts are preferably mixed with other substances, for example with polypeptides or with aromatic syntanes containing sulfo groups, which are purely synthetic,

  such as those cited above.

  For the dyeing process of the invention, the aromatic derivatives containing sulfo groups and mentioned above are preferred, in particular those which do not contain any -SO2- bridge between aromatic rings. In particular, mention should be made of oligophenylene sulfonic acids, lignin sulfonates, condensation products of formaldehyde with naphthalenesulfonic acid, condensation products of formaldehyde with sulfonic acid of a diaryl ether and mixtures of lignins sulfonates with oligophenylene sulfonic acids, with the condensation products of formaldehyde and a naphthalene sulfonic acid or a sulfonic acid of a diaryl ether, or with polypeptides as indicated above and in

  in particular also the corresponding chromium syntanes.

  The basic dye (B) can in general be any dye, in particular a water-soluble dye of basic or cationic nature, for example as defined in the "Color Index" under the name "basic dyes". The basic dyes which can be used according to the invention can belong to any subgroup, and include the anthraquinone, azole (in particular mono- or disazole), azomethine, hydrazone, oxazin, naphtholactam, triphenylmethane, styryl dyes. or pyridone and metalliferous complexes. (for example of metallizable azole or azomethine components or of phthalocyanines). The dyes preferably have an average of 1 to 4 cationic groups in their molecule; the nonmetallic basic dyes preferably have 1-2, more preferably 1.3-2 cationic groups, and the metalliferous complexes preferably 1-4, more preferably 1.5-4 cationic groups on average per dye molecule. The 15 dyes described in European patent application No. 41,040 A1, in particular those defined by formulas III and IV, and in European patent application No. 92,520 A2 in particular those defined by formula III preferably with a radical of formula aa7 in the molecule, are incorporated into the present application for reference. The basic dye (B) used in the process of the invention can be a well-defined dye or a mixture of basic dyes, in particular a mixture of dyes having similar dye behaviors and possibly different shades, for example for three-color dyes. However, it is also possible to use mixtures of basic dyes exhibiting different dyeing behaviors, for example differences in affinity, penetrating power and in unison power, since the dye auxiliary (H) can greatly decrease

  differences in dye behavior.

  The dyeing aid to be used according to the invention is advantageously added in such a way that it is present effectively in the same bath as the dye (B). Although it is possible to combine the method of the invention with a retanning step by adding the dye to the retanning bath before having completed the retanning, it is preferable to carry out any retanning operation before carrying out dyeing according to the method of the invention. The retanning is preferably carried out in a separate bath or, if the bath has not been drained, the retanning is carried out until practically all of the retanning agent has been assembled.

  on the substrate and only components (H) and (B) are added afterwards.

  When the retanning agents (H) used according to the process of the invention as dyeing auxiliaries have an anionic character, they are advantageously added to the bath in such a way

  that they do not cause any undesirable effects, in particular no precipitation with the component (B).

  The following variants are preferred: - (H) is not added simultaneously with (B) to the dye bath. The time interval between the two additions is advantageously at least half a minute, preferably from half a minute to 30 minutes, more preferably from 1 to 20 minutes, in particular up to 15 minutes, if (B) is added after (H), or from half a minute to 90 minutes, preferably from 1 to 30 minutes, more preferably from 1 to 20 minutes, in particular up to 10 minutes, if (H) is added after (B ). If (H) is added after (B), it is particularly advantageous to maintain a time interval of at least 3 minutes between

both additions.

  - (H) is added simultaneously with (B). In this case, it is preferable to add (H) and (B) in the form of anhydrous substances or preparations (preferably powders or granules) or else (B) is combined before being added to the bath, with an excess of (H) to give a composition

easily diluted in water.

  (B) is preferably added after (H), advantageously when (H) is not completely assembled

  and irreversibly on the substrate.

  According to a preferred embodiment of the process of the invention, (B) is added to the bath at the shortest possible time after the addition of (H), suitably as soon as (H) is distributed. homogeneously in the bath (dissolved or dispersed). In particular, in the case of the preferred anionic retanning agents, this time interval can be very short, for example from 1 to 2 minutes, in particular from 1 to 5 minutes. After an interval of te.mps of at least 2 minutes or even only of 1 minute, the retanning agents (H) are already so well distributed in the bath located in the fuller (or also in the beater) that 'we

  can already add the dye (B).

  According to a particular aspect of the invention, it is also possible to add an anionic dye to the same dye bath, the basic and anionic dyes being appropriately added in such a way that their mounting on the substrate

is not exactly simultaneous.

  The subject of the invention is therefore also a process for dyeing tanned leather in an aqueous medium, characterized in that an anionic dye (A) and a basic dye ( B), a retanning agent

  (H) being used as a dye aid.

  The anionic dye (A) can in general be any conventional dye, in particular a water-soluble dye of anionic nature suitable for dyeing leather. Suitable anionic dyes include azole, azomethine dyes, metalliferous complexes of azo dyes and / or azomethine dyes, formazan dyes, polycyclic dyes optionally containing heterocycles (e.g. anthraquinone dyes, quinoline, oxazine, thiazine, dehydrothiotoluidine, coumarin or indole), phthalocyanines, stilbenic dyes or sulfur dyes containing sulfo groups (in particular those designated Bunte salts as defined for example in Venkataraman's work "The Chemistry of Synthetic Dyes", vol. VII, 1974, Academic Press, chapter II, pages 35-68), and the anionic dyes defined in the "Color Index" under the names "Acid Dyes", "Direct Dyes", "Mordant Dyes", "Reactive Dyes", "Solubilised Sulfur Dyes", "Condense. Sulfur Dyes" and "Leather Dyes" and in particular those described therein. It is also possible to use mixtures of anionic dyes, in particular mixtures of anionic dyes having similar dyeing behaviors and possibly different shades, for example for three-color dyes. It is also possible to use mixtures of anionic dyes having different dyeing behaviors, for example differences in affinity, penetrating power and in unison power, since the dye auxiliary (H) used according to the invention decreases

  strongly the differences in dye behavior.

  The dyes (A) and (B) are advantageously added in such a way that they do not act exactly at the same time on the substrate, that is to say that they are not added simultaneously to the dye bath or, s 'they are added simultaneously, they are added in such a way that they do not distribute at the same speed in the bath. The retanning agent 15 (H) used according to the invention as a dyeing aid is advantageously added in such a way that it completely fulfills its role of dyeing aid, in particular penetration aid; preferably it is added at any desired time before the addition of the first dye until at the latest simultaneously with the addition of the second dye. The retanning agent (H) can, for example, be added to the dye bath before the addition of the first dye or between the two additions or can be added together with one of the two dyes (A) or (B) . When (A), (B) and (H) are to be added simultaneously, they are preferably all in solid form, in particular

  in the form of powders or granules.

  The addition of the dyes (A) and (B) is advantageously carried out in such a way that the second is added at a time when the first is not yet completely mounted on the leather, preferably in such a way that the second dye be added when the retanning agent is not yet completely and irreversibly mounted on the substrate. Components (A), (B) and (H) can be added, for example, according to the following variants:

1) A-H-B

2) (A + H) - B 3) A- (H + B)

4) H-A- B

) H-B-A

6) (H + B) -A

7) B-H-A

8) B - (A + H)

1 5 9) (A + H + B)

  (the "+" sign means the simultaneous addition and the "-" sign means the addition in the order indicated at a certain time interval). In variants 3) and 6), the mixture (H + B) is an anhydrous mixture of solid products and in variant 9 (A + H + B) is a mixture of anhydrous substances. The dye aid (H) is preferably added before the addition of dyes having a very high affinity for the substrate, in particular cationic dyes; 25 however, it can also be added advantageously

  in the bath at the same time as the anionic dye.

  The addition of components (A), (H) and (B) is carried out

  preferably in two or three stages, that is to say according to variants 1) to 8), variants 1) to 5) and in particular 1), 2), 4) and 5) being preferred.

  Among these variants, variants 1) and 2) are preferred, variant 2) is particularly preferred

for reasons of economy.

  The time intervals between the different additions can be different and are suitably such that the retanning agent (H) can

  exert maximum influence on the behavior of the 5 dyes (A) and (B), especially on their rise.

  The time intervals between the different additions can advantageously be of the order of half a minute to 20 minutes, preferably from 1 to 10 minutes, more

preferably 1 to 5 minutes.

  The concentration of the retanning agent (H) is suitably at least sufficient to influence the behavior of the dyes and at most must be such that the rise capacity of the dyes is not too much impaired. The concentration of (H) is advantageously at least 1%, preferably from 1 to 8%, more preferably from 2 to 6%, in particular from 3 to 5%, relative to the weight of the tanned hides, at 1 'wet condition. For woolen skins, corresponding amounts of (H) are used, that is to say a ratio of the bath for example of 2,000% relative to the weight of the skins in the dry state, preferably up to 6 g / 1 of (H), in particular from 3 to 6 g / l

from (H).

  The total concentration of dye can vary within wide limits depending on the substrate, the dyeing process, the combination of dyes and the desired dyeing effect and can possibly go as far as the saturation level of the substrate. The total amount of dye is advantageously between 0.02 and 4% relative to the weight of the tanned hides, in the wet state, that is to say approximately 0.04 to 8% relative to the weight skins in the dry state, for example for wools and furs or the woolen part

  or hair can be partially dyed.

  The weight ratio of components (A) and (B) can also vary within wide limits, for example depending on the substrate, the affinity, the shade and intensity of the dye, the desired effect and the dyeing process. The weight ratio (A) / (B) is advantageously between 1:20 and 20: 1,

  preferably between 1: 4 and 4: 1. If desired, the dye bath may contain other conventional auxiliaries.

  Dyeing can be carried out under the usual temperature and pH conditions, advantageously at a temperature of between 10 and 70 ° C., preferably between 25 and 700 ° C., the temperature range of 35 to 55 ° C. being preferred for dyeing leather. and milder temperature conditions, in particular temperatures of the order of 25 to 55,

  being preferred for the treatment of woolen skins.

  The pH values are advantageously between 20 2 and 8, preferably between 3 and 7. The treatment with the dye auxiliary (H) and the dyes (B) or (A) and (B) is preferably carried out at a pH of 4 to 6.5, the pH of the dye bath being preferably lowered at the end of the dyeing process by addition of acid, advantageously to pH values of 3 to 5, preferably to values 44, in particular between 3.3 and 4 for fixing. As acids, it is possible to use, for example, acetic acid or preferably formic acid. After adding the components (H), (B) -and optionally (A) and before any final addition of acid, the treatment of the substrate in the dye bath is continued until the desired penetration is obtained. the dye for a given combination of substrate, dyes, auxiliary and dyeing process can be determined by some preliminary tests and is for example between 15 and 120 minutes, normally between 30 and 90 minutes. The dyeing process can be carried out according to known dyeing processes, for example in the fuller's

  dye, in mixers of the Challenge Cook, 10 Coretan or Hagspiel type, or also in a sewing machine.

  Before any acidification, the dyed substrate can be nourished. When the dyeing process is finished, including any food and / or acidification, the substrate can be washed or rinsed with water and, after drying, be finished according to the usual methods. If desired, the treated leather can be subjected to further treatments, for example being re-fed, waterproofed or finished with an elastic polymer coating or a special top. According to a particular aspect of the invention, the food is carried out in the same bath, in particular after the dyeing and before any acidification. As food agents, the usual leather food agents, for example those described above, can be used. The concentration of the food agent (calculated as dry matter relative to the weight of the substrate in the wet state) is within the usual limits, mainly between 1 and 10%, preferably between 2 and 8%, more preferably between 4 and 8%. In this way, the dyeing process can be combined with a food operation carried out in the same bath, which avoids having to carry out a separate food operation subsequently. Preferably, an anionic food liquor is used. When tanned hides are used in the wet process in the process, it is advantageous to feed them also or only after dyeing. The food agent is advantageously added after an interval of 5 to 90 minutes, preferably from 20 to 60 minutes after addition of the single dye or the second dye. The treatment with the food agent can be carried out for a time usual for such treatments, preferably for 15 to 90 minutes. After the food operation, it is advantageous to lower the pH to the previously mentioned values of 3 - 5, preferably at a value. 4, in particular at a value of 3.3-4, preferably by adding formic acid, mainly to fix the dye. After the addition of the acid, the substrate can be further processed as

indicated previously.

  According to another variant of the process of the invention, it is possible to carry out a subsequent dyeing of the already dyed and fixed substrate, by subsequent addition of the dye (A) or (B) in the same bath, after which, if necessary , the pH is again reduced to a value of 3-5, preferably k4, in particular 25 to a value of 3 - 4. Food can also be carried out after this subsequent dyeing, but before any final lowering of the pH; when doing a subsequent dye, however, it is preferable

  feed between main dye 30 and subsequent dye.

  According to another particular aspect of the invention, the dyed substrate is subjected to a post-treatment with a cationic dyeing aid (K) in the same bath as that used to carry out

  tincture and possibly food.

  The cationic dyeing aid (K) can be any dyeing aid, essentially colorless, soluble or dispersible in water, used for dyeing textiles or leather with water-soluble dyes. The cationic dye auxiliaries (K) which are taken into account are mainly the amino compounds which may be quaternary ammoniums or also non-quaternized amines which

  form ammonium ions in an aqueous medium, in particular in an acidic aqueous medium.

  The amino compounds to be used as auxiliary (K) are mainly the aliphatic mono- or polyamines, for example polymethylenediamines in which the methylene bridge contains from 2 to 6 methylene groups or the polyalkylene polyamines in which the alkylene residue contains from 2 to 4 atoms of carbon and which contain from 3 to 6 amino groups, or the cyclic amines, said mono- or polyamines possibly comprising one or more C9C24 aliphatic hydrocarbon radicals and possibly being benzylated and / or alkylated with C -C4 alkyl radicals, for example the compounds described in DOS 2-508 242, 2 924 471 and 3 534 102, - the reaction products of such mono- or polyamines with cyanamide, dicyanodiamide, guanidine, biguanide, epichlorohydrin, formaldehyde, 30 dicarboxylic acids and / or N-methylolated compounds and optionally with alkylating agents or other reagents, said reaction products containing azo atoms basic te, for example the compounds described in DOS Nos. 3,216,913 and 3,446,284, in PCT application No. 81-2423 and in European patent application No. 151 370, - guanyl compounds containing amino groups as described in British Patent No. 1,238,091,

  - and also the aromatic amino compounds.

  The compound (K) can optionally be mixed with usual additives, in particular with nonionic dispersing agents, preferably hydrophilic (in particular for preparing aqueous dispersions of the amino compounds). As examples of such auxiliaries (K), cite those described in the patents and patent applications indicated above as well as methylolated melamine, and the condensation products of di- (C1-C2 alkyl) amines with epichlorohydrin (0.9: 1 to 5: 4 ) .and aminobenzoate

benzyl (alcoholic solution).

  The post-treatment of the dyes with the dye auxiliary (K) is carried out in the same bath used for the dye and possibly for a

  subsequent dyeing, advantageously under acidic conditions, preferably at a pH of 3 to 5, more preferably at a pH j4, in particular at a pH of 3.3-4.

  The auxiliary (K) is preferably added to the dye bath when the bath after the dye (if a food agent has been added, also after the addition of this food agent and, if a subsequent dye is carried out, also after the subsequent dyeing) has been acidified to the pH values indicated above, preferably to pH values 44, in particular at pH between 3.3 and 4. The auxiliary (K) is advantageously used at a concentration of 0.1 to 2%, preferably 0.2 to 1% calculated as a cationic compound, relative to the weight of the substrate in the wet state. The post-treatment is advantageously carried out at the same temperature intervals as the dyeing, the possible food and the possible lowering of the pH by addition of acid, preferably between 25 and 70 C, in particular between 35 and 55 C for the leather. and between 25 and 55 C for

woolen skins.

  Thanks to this post-treatment, surprisingly good exhaustion of the dye bath is obtained. After this post-treatment, the treated substrate can be washed, rinsed with water according to the usual methods and, after drying, be finished according to the usual methods and, if desired,

  be primed as previously indicated.

  The dye yield, the dye penetration and the solidities, the shine and the unison of the dyes on leather thus obtained are surprisingly good. By adding in a single bath all the treatment substances, that is to say the auxiliary (H), the dyes (B) and possibly (A), and optionally the food agent and preferably cationic post-treatment agent (K), the dyeing process can be carried out in a simple manner

and particularly rational.

  The flower can be dyed very regularly and practically without tanning, even for relatively high concentrations of dye. By an appropriate choice of components (A), (B) and (H), their concentration and the order of the additions, a very wide variety of color effects can be obtained. By the choice of dyes or mixtures of dyes (A) and (B) of the same shade, it is possible to obtain leathers dyed very regularly and using components (A) and (B) of different shades. we can also obtain, if desired, dyes of the edges and dyes of the flower of different shades. In the dyeing of woolen skins or furs, we can also obtain special color effects

  wool or hair side and leather side.

  According to the invention, it is possible to dye lO very well the leather in the slice and with high yields, in particular even thick and very thick leathers, in particular those having a thickness of at least

minus 1 mm.

  The following examples illustrate the present invention without in any way limiting its scope.

  The percentages mean percentages by weight and the temperatures are indicated in degrees Celsius.

  The concentrations indicated in% refer, unless otherwise indicated, to the weight of substrate in the wet state, provided that it is not a question of the concentration of a solution or of a dispersion. The products used are commercial products and their concentrations refer, unless otherwise indicated,

  to the active substance. The dyes are fuller's dyes, unless otherwise indicated.

Example 1

  A chrome tanned cowhide leather 2mm thick, the pH of which was adjusted to 4.5, is retanned in a fresh 40% bath with 100% water and 4% mimosa extract. After 45 minutes of fuller's rotation, 5% of food oil (sulphited fish oil) is added to the same bath and again after 45 minutes, 5% of a polycondensation product - 22 of formaldehyde with 3- naphthalene sulfonic (3/4 molar ratio). After another 5 minutes of fuller's rotation, 2% of the brown dye of Example 157 of European patent application 41040 is added and the dyeing is continued for 1 hour. Then 2% 85% formic acid is added in three additions each separated by an interval of 10 minutes. 30 minutes after the last addition, the pH of the bath is 3.3. The dyed leather is then rinsed, wrung, dried and finished according to the usual methods. The

  treated leather is optimally dyed in the wafer and with a high yield in a brown shade having optimal solidities.

Example 2

  In a fresh bath containing 100% water at 40 and 2% of the basic dye CI Basic Blue 3, a chrome tanned cowhide leather 2 mm thick is introduced, the pH of which has been adjusted to 4.5, and we dye for 1 hour. 5% of the same penetration aid as that of Example 1 is then introduced and the treatment is continued for 1 hour. The leather is then fed in the same bath with 5% of a sulfited fish oil and after 45 minutes 2% of 85% formic acid is added in three additions, each addition being carried out at 10 minute intervals. 30 minutes after the last addition, the pH of the bath is 3.3. Leather is

  then rinsed, wrung, dried and finished according to the usual methods. A dyed leather is obtained in the edge optically and with a high yield in a brilliant blue shade having optimal solidities.

Example 3

  The procedure is as described in Example 2 except that the penetration aid is added 5 minutes, instead of 1 hour, 30 after the basic dye.

  EXAMPLES 4 AND 5 The procedure is as described in Examples 1 and 2, but instead of the indicated dyeing aid, the same amount of a semi-synthetic retanning agent consisting of a mixture of equal parts of chromium and protein ligninsulfonate - 23 (degraded leather fibers). We get dyed leathers in the

  edge with optimal solidity and gloss.

  By proceeding as described in Examples 1 and 2, the following dyes can be used: CI Basic Brown 1, CI Basic Green 1, CI Basic Green 4, CI Basic Blue 9, CI Basic Blue 22, CI Basic Blue 154, CI Basic Orange 21, CI Basic Orange 64,

  C.I. Basic Red 14, C.I. Basic Red 22, C.I. Basic Red 111, C.I.

  Basic Violet 16, CI Basic Red 27, CI Basic Yellow 2, CI Basic Yellow 11, CI Basic Yellow 13, CI Basic Yellow 60, CI Basic 10 Yellow 94, the dyes of examples 128, 139, 141, 151, 154 and 157 of European patent application 41040 and the dye of

  Example 35a of European patent application 92520.

  In examples 1 and 2, instead of the single colorant

  used, it is also possible to use a mixture of two or more dyes having similar dyeing properties.

Example 6

  In a cool bath containing 100% 40% water, 2% mimosa extract, 2% aromatic syntane (product of condensation of formaldehyde with B-naphthalene sulfonic acid) and 2% of a polyacrylate-based resin retanning agent, a 2 mm thick chrome tanned cowhide, the pH of which has been adjusted to 4.5, is retanned. After 45 minutes of fuller's rotation, the bath is evacuated and 100% to 50 and 5% of a polycondensation product of formaldehyde and of nnaphthalene-sulfonic acid are added. After 5 minutes of fuller's rotation, 0.7% of the dye mixture is added 0.4% CI Basic Yellow 82 0.1% CI Basic Red 59 0.2% CI Basic Blue 411 and the dyeing is continued for 40 minutes . 5% of a food liquor is then added (sulphited fish oil,

  dry matter 75%) and after another 45 minutes 2% formic acid 35% 85% in three additions, each addition being carried out at

  - 24 tervalles of 10 minutes. 30 minutes after the last addition, the pH of the bath is 3.3. 2% of the aqueous product of Example 2 of DOS 29 24 471 is added to the bath and the treatment is continued for 30 minutes. The dyed leather is then rinsed, wrung out, dried and finished according to the usual methods. The leather thus treated is optimally dyed in the wafer with a high yield; the dye stands out for its optimal solidity. By following a procedure analogous to that described in Example 6, other combinations of dyes can be used to

  three-color process in which the yellow, red and blue components mentioned above have been replaced by one or more of the following components: C.I. Basic Orange 64, C.I. Basic Red 11 and C.I.

  Basic Blue 154 or also combinations of these components.

  By proceeding in a similar manner to that described in Example 6, the other dyes mentioned in Examples 1 and 5 can be used, for example in the form of dyes used alone.

Example-7

  We proceed as described in example 6 majis we use the

  N, N'-bis- (3-aminopropyl) -ethylenediamine in place of the product of Example 2 of DOS 29 24 471.

Example 8

  (In this example, the percentages refer to the weight

of the substrate in the dry state).

  A reverse suede of chromium-tanned sheep skin (intro25 duit in the dry state) is treated with a fuller for 15 minutes with 2000% water at 30 containing the following products: lg / l of the condensation product of formaldehyde with l B-naphthalene sulfonic acid, lg / l of the sodium salt of decaethylene glycolic ether of lauric alcohol partially carboxymethylated, lg / l of coconut sulfated oil and lg / l of ammonia. 5 g / l of the polycondensation product of formaldehyde and of 5-naphthalenesulfonic acid are added and 2 minutes later 1.8 g / l of the basic dye according to Example 141 of European patent application 41040. The dye for 45 minutes. 2 g / l of sulphited fish oil (dry matter content 75%) are then added and after 20 minutes of fulling, 2 g / l of formic acid are added to

  acidification and treatment is continued for 30 minutes.

  The sheepskins thus treated are rinsed with water and finished

according to the usual methods.

Example 9

  The procedure is as described in Example 8 with the difference that, after the addition of acid, 2 g / l of the auxiliary is added.

  cationic dye described in Example 6 and the treatment is continued for 30 minutes. The treated substrate is then rinsed and finished as indicated in Example 8.

  According to another variant of the dyeing process of Examples 8 and 9, it is possible to use, in place of the undyed suede backing, a suede backing in which the wool part has been dyed with

  a dye for wool, with or without reservation of the leather part.

  Very good dyes are also obtained if, in Examples 8 and 9, the product of Example 2 of DOS 29 24 471 is replaced by a corresponding amount of one of the following products: - Nbenzyl-N chloride, N-dimethyl-alkylammonium o alkyl si20 gnifies the fatty residue of tallow - the condensation product according to example i of European patent application 151 370, in the form of sulphate - the condensation product of dimethylamine and epichlorohydrin (1/1) - trimethylolmelamine - the product according to example A of the British patent

no 1,238,091.

Example 10

  A 2 mm thick chrome-tanned cowhide is retanned as follows: the wet leather is treated with a fuller for 40 minutes in a fresh bath consisting of 200% water at 45, 1% dimethylolethylene-urea and 0 , 5% of a condensation product based on a sulfonic acid of diphenyl ether (sulfone). The bath is then drained. After fulling for 20 minutes with 100% water at 35 ', 1% of condensation product (sodium salt) of the

- 26 260-1050

  -26 formaldehyde with 3-naphthalene sulfonic acid and 1% sodium formate, 1.2% of a polyacrylate-based retanning agent is added and the treatment is continued for 20 minutes. 3% of melamine / formaldehyde resin and 3% of dimethylolurea 5 are then added and, after fulling for another 60 minutes, the bath is drained (bath pH = 4.6). Dyeing is then carried out as follows: 150% of water is added to 50.3.6% of the polycondensation product (sodium salt) of formaldehyde with B-naphthalenesulfonic acid and 0.5% of the brown dye CI Acid Brown 362 and after 2 10 minutes of rotation, 0.5% of the brown dye of Example 157 of European patent application 41040 and 0.5% of the basic dye C.1 are added. Basic Yellow 60 and continue dyeing for 40 minutes. Then 7% of a 60% emulsion of a sulfited fish oil is added as a food agent. After 40 minutes of rotation of the fuller, 1% of 85% formic acid is diluted 1:10 and after another 10 minutes of rotation of the fuller, another 1% of 85% formic acid is diluted 1: 1 10 and the treatment is continued for 30 minutes. The pH is then 3.5. The treated leather is rinsed at

  running water, wrung, dried and finished according to usual methods.

Example 11

  The operation is carried out as described in Example 10, using a double quantity of dye and adding 1% of the aqueous product of Example 2 of DOS 29 24 471 after the addition of formic acid 25 and before rinsing. The post-treatment of this product is continued for 30 minutes after which the dyed leather is rinsed, wrung, dried and finished according to the usual methods. Thus, with high yields, a leather with a uniformly dyed edge is obtained; the dye exhibits optimal solidities. Example 12 The procedure is as described in Example 10 or 11 with the difference that the anionic dye C.I. Acid Brown 362 is added 1

  minute after the addition of the polycondensation product (sodium salt) of formaldehyde with 3-naphthalene sulfonic acid, the mixture of cationic dyes being added 2 minutes after the addition of the anionic dye.

- 27

Example 13

  The procedure is as described in Example 10 or 11 with the difference that the polycondensation product (sodium salt) of formaldehyde with (-naphthalene-sulfonic acid) is added to the bath 1 minute after the addition of the anionic dye CI Acid Brown 362 and the mixture of cationic dyes is added 2 minutes after

  adding the polycondensation product.

Example 14

  The procedure is as described in Example 12 with the difference that the sequence of addition of the dyes is reversed, that is to say first the polycondensation product (sodium salt) of formaldehyde with acid 3 is added. -naphthalene-sulfonic, after 1 minute the mixture of cationic dyes is added and after 2 minutes the anionic dye is added. Example 15 The procedure is as described in Example 14 with the difference that the sequence of addition of the dyes and of the polycondensation product is as follows: first the mixture of cationic dyes, after 1 minute the polycondensation product (salt of so20 dium) of formaldehyde with B-naphthalene sulfonic acid, after 2

minutes the anionic dye.

  Examples 16 to 21 The procedure is carried out as described in Examples 10 h 15 min, but the dye C.I. Acid Brown 362 is replaced by a mixture consisting of 1 part of C.I. Acid Brown 127, 2 parts of C.I. Direct Yellow 133

  and 2 parts of C.I. Mordant Brown 79.

Example 22

  A neutralized chrome-tanned 0.8 mm thick sheep skin is subjected to further neutralization by the addition of 150% water at 40 ', 1% sodium formate and after 10 minutes 1% sodium bicarbonate. After 30 minutes of fuller's rotation, 1.6% of a polyacrylate-based retanning agent and 3% of dimethylolurea are added for retanning. After 20 minutes of fuller's rotation, 3% of quebracho extract and 2% of polycondensation product (sodium salt) of formaldehyde with

- 28 2601050

  - 28 B-naphthalene sulfonic acid. After 80 minutes of rotation at

  fuller, the bath is drained (pH of the bath = 4.5).

  After washing for 10 minutes with 300% water at 550, the bath is drained off and 150% water at 55.3.2% of polycondensation product (sodium salt) of formaldehyde with 3- acid is added. naphthalene sulphonic and 1% of anionic dye CI Direct Black 155. After 3 minutes of fuller's rotation, 1.8% of the cationic black dye is added according to example 35a of European patent application 92520 and the dyeing is continued for 40 minutes. 10 The leather is then fed by adding 8% of an aqueous emulsion to 60% of a sulphited fish oil and 2.7% of a partial ester of phosphoric acid with the fatty alcohol of tetraethoxylated tallow (salt monoethanolamine) and treatment is continued for 60 minutes. 1% formic acid is then added and, after 10 minutes, again 1% formic acid and the treatment is continued for 30 minutes. Then 1% of the cationic black dye of Example 35a of European patent application 92520 is added. After 30 minutes of fuller's rotation, 2% of formic acid is added and the treatment is continued for another 30 minutes. Then 1% of the product according to Example 2 of DOS 29 24 471 is added and the treatment is continued for 30 minutes. The substrate thus treated is then rinsed with water, wrung, dried and finished according to the usual methods. The resulting dye is solid and solid and

of remarkable penetration.

  Very good dyes are also obtained if, in Examples 11 to 22, the product of Example 2 of DOS 29 24 471 is replaced by an equivalent quantity of one of the following products: - Nbenzyl-N chloride, N- dimethylalkylammonium o alkyl si30 gnifies the fatty residue of tallow - the condensation product according to Example 1 - of European patent application No. 151 370, in the form of sulfate - the condensation product of dimethylamine and epichlorohydrin (1 / 1) - trimethylolmelamine

260 1,050

  - 29 - the product according to example A of the British patent

no 1,238,091.

  Example 23 (dyeing in an elbow) (The percentages refer to the weight of the substrate in the dry state). In a sewing machine, a suede reverse side of chromium-tanned sheep skin is introduced in the dry state and it is treated for 15 minutes with 2000% water containing 30 g / l of the polycondensation product (sodium salt) of the formaldehyde with 3-naphta10 lenesulfonic acid, 1 g / l of the sodium salt of decaethylene glycol ether of lauric alcohol, partially carboxymethylated, 1 g / l of coconut oil sulfated and ig / l of ammonia. 5 g / l of the polycondensation product (sodium salt) of formaldehyde with 3naphthalene sulfonic acid are then added together with 0.5 g / l of the dye C.I. Acid Brown 362, and after 2 minutes

  add 1 g / l of the basic dye from Example 141 of European patent application 41040. The dyeing is continued for 45 minutes.

  After this period, 2 g / l of sulfited fish oil (dry matter content 75%) are added. The treatment is continued for 20 minutes and then acidified by the addition of 2 g / l of formic acid. The treatment is continued in the sewing machine for a further 30 minutes, then the treated skins are rinsed and finished according to

the usual methods.

  By following a procedure analogous to that described in Examples 10 to 23, the following anionic dyes can be used: C.I. Direct Black 19, 118, 155 or 163; C.I. Direct Blue 1, 15, 67, 77, 86, 106, 158, 159, 251, 262 or 267; C.I. Direct Green 26; C.I. Direct Yellow 6, 11, 28, 68, 93 or 132; C.I. Direct Orange 39 or 40; C.I. Direct Red 23, 24, 26, 63, 80, 83, 95, 111, 223 or 239; C.I. Direct Brown 169 or 170; C.I. Direct Violet 66;

260 1 0 5 0

  - 30 C.I. Mordant Brown 79; C.I. Mordant Orange 6 or 10; C.I. Solubilized Sulfur Black 1; C.I. Solubilized Sulfur Blue 11; C.I. Solubilized Sulfur Red 6; C.I. Solubilized Sulfur Brown 10 or 14; C.I. Reactive Yellow 34; C.I. Reactive Orange 14, 26 or 33; C.I. Reactive Red 8; C.I. Reactive Brown 12; C.I. Reactive Blue 1 or 60; C.I. Acid Yellow 19, 65, 111, 112, 127, 204, 235 or 243; C.I. Acid Orange 3, 7, 67, 80, 82, 94, 95, 135, 168 or 170; C.I. Acid Green 9, 16, 20, 28, 60, 80, 106, 111 or 112; C.I. Acid Blue 25, 80, 83, 90, 113, 193, 227, 247, 250, 296, 312 or 334; C.I. Acid Black 1, 50, 58, 76, 115, 132, 170, 194, 209, 215 or 218; C.I. Acid Violet 48, 66, 90 or 128; C.I. Acid Red 4, 88, 97, 106, 114, 119, 215, 217, 261, 263, 362, 399 or 404; C.I. Acid Brown 28, 30, 53, 58, 75, 98, 126, 127, 188, 235, 237,

  276, 289, 298, 303, 304, 311, 358, 359, 360, 362, 363, 396,

  397, 402, 404, 409, 425, 426 or 432;

  or suitable mixtures of the dyes mentioned.

  In place of the cationic dyes or mixtures of cationic dyes mentioned in Examples 10 to 23, the following cationic dyes or mixtures of cationic dyes may be used, together with the anionic dye chosen:

  C.I. Basic Brown 1, C.I. Basic Green 1, C.I. Basic Green 4, C.I.

  Basic Blue 9, CI Basic Blue 22, CI Basic Blue 154, CI Basic Orange 21, CI Basic Orange 64, CI Basic Red 14, CI Basic Red 22, CI Basic Red 111, CI Basic Violet 16, CI Basic Red 35 27, CI Basic Yellow 2, CI Basic Yellow 11, CI Basic Yellow - 31 13, CI Basic Yellow 60, CI Basic Yellow 94, the dyes of

  Examples 128, 139, 141, 151, 154 and 157 of European patent application 41040 and the dye of Example 35a of European patent application 92520.

- 32

Claims (18)

  1.- The use of retanning agents as auxiliaries for the sliced dyeing, in an aqueous medium, of leather tanned with a basic dye and possibly an anionic dye. 2.- A process for dyeing tanned leather, characterized in that the leather is dyed in an aqueous medium with a basic dye B, a retanning agent H being used as an auxiliary of dye.   3.- A method according to claim 2, characterized in that   an anionic dye A is also used, A and B being added in any desired order.   4. A method according to claim 3, characterized in that one of the two dyes A and B is added when the other is not completely mounted on the leather and the retanning agent H is added to the bath dye at any time before the addition of the first of the two dyes until at the latest at the same time as   adding the second of the two dyes.   5. A method according to claim 4, characterized in that the dye B is added after the addition of A and / or H.   6.- A method according to any one of claims 2   to 5, characterized in that B is added to the bath after H.   7.- A method according to any one of claims 2   to 5, characterized in that the dye B and the retanning agent H 25 are added at the same time, B and H being in the form of powder or granules.   8.- A method according to any one of claims   3, 4 and 7, characterized in that the dyes A and.B and the retanning agent H are added at the same time, in the form of powder or granules,   9. A method according to any one of claims 2   to 8, characterized in that the single colorant, or the second colorant, is added when the retanning agent H is not mounted   completely and irreversibly on the substrate. - 33   10.- A method according to any one of claims   2 to 9, characterized in that the dye auxiliary H is a   anionic retanning agent containing sulfo groups.   11.- A method according to any one of claims   2 to 10, characterized in that the substrate is retanned before dyeing.   12.- A method according to any one of claims   2 to 11, characterized in that the substrate is fed in the same bath. 13.- A method according to claim 12, characterized in   what food is done after tincture.   14.- A method according to claim 12 or 13, characterized in that the food is carried out in the same bath before and after dyeing.   15.- A method according to any one of claims   2 to 14, characterized in that the fixing is carried out at a pH between 3 and 5.   16. A method according to claim 15, characterized in that, after fixing, a subsequent dyeing is carried out in the same bath by adding the dye A or B, and if necessary,   again fixes at a pH between 3 and 5.   17.- A method according to any one of claims   2 to 16, characterized in that a post-treatment is carried out in the same bath with a cationic dye auxiliary K. 18.- Leather, characterized in that it has been dyed according to the   process specified in any one of claims 2 to 17.