EP1118682B1 - Preparations of tanning/ retanning agents - Google Patents

Description

The invention relates to solid tannin / retanning preparations, a method for their production, their use for tanning and retanning as well as with them tanned and retanned leather and furs.

The production of leather and furs from hides and skins usually takes place in several steps. After the preparatory work of the water workshop how Dehairing, meat removal, descaling and pickling consists of a typical sequence Tanning, retanning, coloring, greasing and dressing. The individual work steps can be divided into further subunits.

While the tanning process increases the leather's shrinking temperature, retanning has hardly any influence on it. "Retanning" means that Aftertreatment of pre-tanned (generally chrome-tanned) leather to Color, levelness, softness, fullness and behavior against water (hydrophobicity) to optimize and fix tannins.

Tanning, retanning and dyeing in particular are usually carried out in different ways so-called tanning drums using aqueous tanning / retanning solutions or dispersions or dye solutions carried out. Most of the tannins and tanning agents used are powdered Solid added to the tanning tanks (fleets), which makes handling easy and minimal storage space guaranteed. To rationalize these steps have been mixtures of various powdered tannins in the past and tanning aids are manufactured, with which the tanning process by saving of path and add operations to be simplified.

EP-A 849 365 describes a solid agent for the simultaneous retanning and greasing of Leather described, which in addition to ordinary powdered, water-soluble After-tanning agents are other normally liquid or waxy, non-aqueous oils and contains fats.

Some of the retanning agents, for example the polymeric retanning agents, where 10 to 80% by weight of the monomer units carry one or more C ₂ -C ₄₀ -alkyl radicals and this polymer contains 1 to 10 mol / kg of acid groups, in particular carboxylic acid and / or carboxylate groups so far, however, mostly added to the aqueous liquors in the form of their aqueous solutions or suspensions. Attempts to obtain equivalent powdered dosage forms by simply drying failed. The products obtained in this way often have poor redispersibility or other disadvantageous effects of the solid forms.

• wenigstens eine Verbindung A), die in der Lage ist, die Schrumpfungstemperatur einer ungegerbten Blöße um wenigstens 10°C zu erhöhen, indem man die Blöße mit einer Verbindung A) in Wasser bei einer Temperatur von 20 bis 50°C behandelt,
• wenigstens eine davon verschiedene polymere Verbindung B), wobei 10 bis 80 Gew.-% der Monomereinheiten einen oder mehrere C₂-C₄₀-Alkylreste tragen und das Polymer B) 1 bis 10 mol/kg Säuregruppen, insbesondere Carbonsäure- und/oder Carboxylatgruppen enthält und gegebenenfalls
• weitere Zusatzstoffe C).

Solid preparations have now surprisingly been found to contain

• at least one compound A) capable of increasing the shrinkage temperature of an untanned pelt by at least 10 ° C by treating the pelt with a compound A) in water at a temperature of 20 to 50 ° C,
• at least one different polymeric compound B), 10 to 80% by weight of the monomer units carrying one or more C ₂ -C ₄₀ -alkyl radicals and polymer B) 1 to 10 mol / kg of acid groups, in particular carboxylic acid and / or carboxylate groups contains and if necessary
• further additives C).

The solid preparations according to the invention are preferably in the form of powder or Granules before. Granules are in particular those with an average grain size from 0.5 to 5 mm is preferred. The solid preparations according to the invention in the form Their granules are also not dusty and very free-flowing.

The preparations according to the invention are also in a preferred embodiment completely soluble or emulsifiable in water, the solubility or emulsifiability is preferably more than 50 g / l at 20 ° C.

The preparations according to the invention preferably contain, based on the preparation 25 to 95% by weight at least one compound A), 5 to 50% by weight at least one compound B) and 0 to 50% by weight one or more additives C).

However, the preparations according to the invention containing are preferred 30 to 70% by weight at least one compound A), 15 to 40% by weight at least one compound B) and 0 to 40% by weight further additives C), 5 to 20% by weight of a neutralizing agent being preferred as additive C). Preferred compounds A) are tannins, in particular solid tannins, which are selected with particular preference from the group of mineral tannins, vegetable tannins, syntans and resin tannins.

As mineral tanning agents are e.g. Salts of chrome, aluminum or zirconium, but especially trivalent chromium compounds such as chromium sulfate, basic To name chromium sulfate or chromium acetate.

Vegetable tanning agents are generally understood to mean tanning agents which are caused by Extraction, drying and optionally post-treatment from various Plants or parts of plants are obtained, e.g. Chestnut, sweet chestnut, Mimosa, Quebracho, Tara, or similar substances, the so-called hydrolyzable or contain condensed tannins (see e.g. Reich, G. Theory and practice of organic Tanning agents, part 1: general principles and natural organic tanning agents, The leather, 1996, 74-83).

The synthetic organic tannins, also called syntans, are mostly through Sulfonation or sulfomethylation solubilized aldehyde condensation products aromatic base, in particular of phenol, cresol, naphthalene and Naphthol, Biaryl, Biarylether and Biarylsulfone. Are particularly preferred Condensates from naphthalenesulfonic acids, phenolsulfonic acid, diphenyl sulfones or sulfonated diaryl ethers with formaldehyde and / or urea. Such condensates are known, for example, from Herfeld (editor) "Bibliothek des Leders", vol. 3, pages 53 to 59, Umschau-Verlag 1984 or Reich, G. Theory and Practice of organic tanning agents, part 2: synthetic organic tanning agents, leather, 1996, 157-171 and can according to the references given there described methods are produced.

Among the so-called resin tanning agents, cationic ones are preferred Condensation products of nitrogen-containing compounds, especially urea, dicyanamide or melamine with formaldehyde and their anionic reaction products with compounds such as phenol, sulfonated aromatics or sulfites Roger that.

The preparations according to the invention contain in a preferred embodiment as compound A) aromatic syntans from the condensation of naphthalenesulfonic acid, Phenolsulfonic acid, bishydroxyphenyl sulfone and / or ditolyl ether sulfonic acids with formaldehyde and / or urea.

In a further particularly preferred embodiment, the connection A) 40-90% by weight of such syntans from the condensation of naphthalenesulfonic acid, Phenolsulfonic acid, bishydroxyphenyl sulfone or ditolyl ether sulfonic acids Formaldehyde and / or urea in combination with mineral tannins, especially trivalent chromium compounds such as chromium sulfate or chromium acetate and / or resin tanning agents used.

Tanning should be preferred under treatment in water at 20-50 ° C to be understood under conditions and with amounts as used in the Craftsman trained specialist for the respective groups of substances as typical. As a guide, e.g. the regulations in Herfeld (ed.) "library des Leders ", Umschau Verlag, 1984, Vol. 3, S 306-314, Examples 10-16 subsequent measurement of the shrinkage temperature is carried out according to that in DIN EN 12993 given method.

Polymeric retanning agents from the class are preferably used as compound B) of polyacrylates or polyaspartic acids, but especially polyaspartic acids.

Preferred preparations are also those in which the polymeric compound B) is selected from the group of poly (meth) acrylates and poly (meth) acrylate copolymers (B 1) or polyaspartic acids (B 2).

Particularly preferred compounds from the group of poly (meth) acrylates and poly (meth) acrylate copolymers (B 1) are obtained, for. B. by polymerization of hydrophilic monomers such as (meth) acrylic acid, maleic acid or acrylic amides with (C ₁ - C ₂ ) amine constituents with 10-80% by weight of hydrophobic monomers such as alkenes, allyl esters, (meth) acrylic acid esters or acrylic acid amides Amine constituents, each with a chain length of (C ₃ - C ₄₀ ), or by polymerizing monomers such as (meth) acrylic acid, maleic anhydride or (meth) acrylic acid esters with (C ₁ - C ₂ ) alcohol components and subsequent partial Esterification or transesterification with (C ₂ - C ₄₀ ) alcohols.

Particularly preferred compounds from the group of polyaspartic acids (B 2) are e.g. B. the reaction products of polysuccinimide with 0.10 - 0.80 molar equivalents of amines or alcohols (C ₂ - C ₄₀ ) and subsequent partial neutralization with inorganic bases such as sodium hydroxide or potassium hydroxide.

In a preferred embodiment, the polymeric compounds B) average molecular weight of less than 100,000, especially smaller 20,000 g / mol.

In a further particularly preferred embodiment, the polymeric compounds B) common that they are not used as a solid, anhydrous preparation can be, because after removal of the solvent z. B. no longer redispersible or are not stable in storage.

The preparations according to the invention can of course also be used for other purposes Contain additives C). As such there are, for example, neutralizing agents, Dispersants, defoamers, water repellents or dyeing aids in question.

Alkali salts of aromatic, for example, can be used as neutralizing agents Sulphonic acids, weak inorganic acids or mono- or dicarboxylic acids be used. The neutralizing agents are preferred in an amount of 5 up to 20 wt .-%, based on the solid preparation, used.

A very particularly preferred preparation contains e.g. B. 30 - 65 wt .-% of aromatic Syntanen A) in a mixture with 10 - 40 wt .-% of neutralizing and dispersing additives C) and 15-25% by weight of a polymeric retanning agent B) based on polyaspartic acid. This preparation is preferably as Granules before.

Another very particularly preferred preparation contains 40-70% by weight a mixture of trivalent chromium salts, aromatic syntans and Resin tannins as compound A), 15-30% by weight of neutralizing additives C) and 15-40% by weight of a polymeric retanning agent B) from the group the poly (meth) acrylates or the polyaspartic acids. Get the percentages each on the preparation.

A preparation containing 20-40% by weight of aromatic is also preferred Syntanen, 20 - 40 wt .-% of resin tanning agents and 30 - 40 wt .-% of neutralizing and dispersing additives with the help of 10 - 25 % By weight of a polymeric retanning agent B).

The preparations mentioned are low in dust and free-flowing.

The present invention also relates to a method for producing the invention Preparations that are characterized by the fact that one can connect A) optionally in a mixture with C) an aqueous solution and / or suspension of B) and, if necessary, during or after the Adding B) dries. Compound B) is preferably added a solid form of the compounds A) and optionally C). Especially done the addition by spraying on an aqueous solution or suspension of B) within a mixer. The mixture obtained can initially have pasty shapes accept. The during or after the addition of the aqueous Solution / suspension of B) subsequent drying is preferably carried out 20 to 200 ° C, especially at 20 to 105 ° C, most preferably at 50 to 100 ° C. The method according to the invention is also very particularly preferred, if the additions of the polymeric compound B) in an aqueous solution or aqueous suspension with a solids content of B) of 5 to 60%, in particular 10 to 50% is done.

The invention further relates to the use of the preparations according to the invention for tanning and retanning pretreated hides or skins in water Fleet. At the same time, it is preferred to use the preparations according to the invention Manufacture leather or fur to use by pre-tanning Leather or furs in an aqueous liquor with the preparations according to the invention treated. Leather or furs that are produced are therefore also part of the invention have been using the preparations according to the invention as Tanning or retanning agents or those obtainable through the use according to the invention.

In a preferred use, the leathers according to the invention are produced by using a commercial tanning equipment such as a tanning drum, blender or Dosamat pickled pellets with 6-10% by weight of the product according to the invention Tanned 20 to 45 ° C. There are no further addition steps during the tanning process necessary. The tanned leather is washed and aftertreated in the usual manner, retanning and greasing are eliminated or significantly reduced Way can be done.

In a further preferred embodiment, commercially available wet blue is applied set a pH of about 3.5 and then in an aqueous liquor with 10-15 % By weight of the agent according to the invention retanned. The leather treated in this way can are processed further in the customary manner, with no subsequent greasing or can be carried out in a significantly reduced form.

You get with both the tanning and the retanning Products according to the invention leather which, particularly with regard to softness and Surface character, have significantly improved properties compared to Substrates that have been treated with conventional products such as Mixtures of salts of trivalent chromium with syntans and neutralizing agents with 7-16% content of chromium, or retanning compounds 20-50% syntans, 20-50% resin tannins and 10-50% neutralizers.

Example 1: Synthetic tanning agent A I:

Naphthalene is sulfonated with 1.4 molar equivalents of H ₂ SO ₄ at 145 ° C for 2 hours. A mixture of 1000 g of the naphthalenesulfonic acids thus obtained, 800 g of bishydroxyphenyl sulfone and 250 ml of 37% by weight formaldehyde solution is condensed at 100-120 ° C. for 3 hours. The product obtained is adjusted to pH 3.5 and an acid number of 80 with sodium hydroxide solution and phthalic acid and spray-dried. When used as the sole tanning agent, shrinking temperatures of the leather obtained of 72-78 ° C. can be achieved.

Example 2: Synthetic tanning agent A II:

Phenol is sulfonated with 0.88 molar equivalents of H ₂ SO ₄ at 100 - 180 ° C. The resulting mixture of phenolsulfonic acid and bishydroxyphenylsulfone is neutralized with sodium hydroxide solution and then condensed with 0.44 molar equivalents of formaldehyde at 100-120 ° C. The raw condensate is adjusted to pH 3.7 and an acid number of 80 with glutaric acid and spray-dried. When used as the sole tanning agent, the leather's shrinking temperatures of 72 - 80 ° C can be achieved.

Example 3: Synthetic tanning agent A III:

Naphthalene is sulfonated with 1.4 mol H ₂ SO ₄ at 145 ° C. for 3 hours, condensed with 0.66 mol formaldehyde for 3 hours, cooled, adjusted to pH 3.5 and an acid number of 50 with sodium hydroxide solution and glutaric acid and spray-dried. When used alone, leather shrink temperatures of 68 - 72 ° C can be achieved.

Example 4: Synthetic tanning agent A IV:

1 mol of dicyanamide is in the presence of 0.1 mol of sodium bisulfite and 50 parts of sulfite waste liquor condensed with 2 moles of formaldehyde. Excess formaldehyde is removed Ammonia bound as hexamethylenetetramine. The solution obtained is spray dried. When used alone, shrink temperatures can be reduced achieve from 70 - 75 ° C.

Example 5: Liquid, polymeric retanning agent B I:

A solution of 1000 g maleic anhydride, 800 g diethylene glycol and 800 g ammonia solution (25%) is condensed in 4 hours at an increasing temperature of 60 - 145 ° C and then volatile components are distilled off. It is reacted with 700 g of hydrogenated tallow fatty amine for 6 hours, cooled to 110 ° C. and mixed with 170 g of oleic acid and 10 g of a silicone-containing defoamer. The hot reaction product is dispersed in 3 l of a 2.5% by weight ethanolamine solution, neutralized with sodium hydroxide solution and bleached with hydrogen peroxide.
(see DE-A 19 959 949, component B ₂ (PAS 1)).

Example 6: Liquid, polymeric retanning agent B II:

24 g of AIBN (azoisobutyronitrile) in 340 ml of toluene are continuously added to a solution of 600 g of maleic anhydride and 1000 g of diisobutylene in 1200 ml of toluene at 75-95 ° C. in the course of 4 hours. After 3.5 hours, 35 g of styrene are metered in once. After stirring for 6 hours at 95 ° C., a solution of 1400 g of a fatty alcohol mixture (C ₁₂ -C ₁₈ ) in 4.4 l of toluene is added and the mixture is esterified at 80 ° C. for 24 hours. The mixture is neutralized with stirring with 245 g of sodium hydroxide solution in 11.8 l of water and the organic solvent is subsequently removed under reduced pressure by azeotropic distillation.
(EP-A 0 648 846, Examples A, 4.)

Example 7: Liquid, polymeric retanning agent B III:

400 g of acrylic acid, 600 g of cetyl-eicosyl methacrylate, 10 g of radical initiator azoisopentanoic acid nitrile and a solution of 20 g of 3-mercaptopropanoic acid in 165 g of water are simultaneously added to 900 g of tert-butanol at 85 ° C. for 2 hours at a constant flow rate. Then 1 g of azoisopentanoic acid nitrile in 5 g of tert-butanol is added and the mixture is stirred at 85 ° C. for 1 hour. The mixture is dispersed in 2.5 kg of 10% sodium hydroxide solution and the organic solvent is removed by distillation.
(EP-A 0 579 267, examples Process A)

Example 8: Additive C I:

1000 g of naphthalene is sulfonated at 140-145 ° C. with 3 molar equivalents of H ₂ SO _{4 for} 8 hours, adjusted to pH 7 with sodium hydroxide solution and the crude product mixture is spray-dried.

Example 9: Additive C II:

1000 g of ditolyl ether are sulfonated with 1.7 molar equivalents of H ₂ SO ₄ at 120-125 ° C. for 4 hours and then the mixture of sulfonic acids at 105-108 ° C. with 0.7 equivalents of formaldehyde. condensed. The cooled solution of the raw condensate is adjusted to pH 7 with sodium hydroxide solution and spray dried.

Example 10: Additive C III:

1000 g of phenol are sulfonated with 2 molar equivalents of H ₂ SO ₄ at 120 ° C. for 2 hours. After cooling, the pH is adjusted to 6.5 with ammonia and the powder is transferred by spray drying.

Examples 11-17: Preparation of the mixtures Example 11:

35 parts of Cr ₂ (SO ₄ ) ₃ , 15 parts of synthetic tanning agent AI, 15 parts of synthetic tanning agent A IV, 20 parts of additive C II, 10 parts of Na ₂ CO ₃ and 5 parts of NaHCO ₂ are mixed homogeneously at room temperature. Then, in a mixed agglomeration apparatus at 90 ° C., 40 parts of polymeric retanning agent B III are added. A green, free-flowing granulate is obtained, which is soluble in water at room temperature without residue.

Tl mean parts by weight.

Example 12:

45 parts of Cr ₂ (SO ₄ ) ₃ , 15 parts of synthetic tanning agent A IV, 15 parts of glutaric acid, 15 parts of NaHCO ₃ and 10 parts of MgO are mixed homogeneously at room temperature. 50 parts of retanning agent BI are continuously added at 60 ° C. in a mis agglomeration apparatus. A green, free-flowing granulate is obtained, which dissolves without residue in water at 40 ° C.

Example 13:

20 parts of Tara, 20 parts of Mimosa, 20 parts of synthetic tanning agent AI, 30 parts of additive CI and 10 parts of NaHCO ₃ are mixed homogeneously at room temperature and mixed with 60 parts of polymeric retanning agent B III at 80 ° C. The paste obtained is extruded hot. After cooling, a free-flowing, storage-stable granulate is obtained.

Example 14:

40 parts of synthetic tanning agent A II, 35 parts of additive C II, 10 parts of additive C III and 15 parts of Na acetate are dissolved in 60 parts of water at 80 ° C and then 100 parts of polymeric retanning agent B II were added. It is dried by fluidized bed spray granulation at 140 to 150 ° C supply air temperature and receives a fine-grained, free-flowing granules.

Example 15:

50 parts of synthetic tanning agent AI, 10 parts of synthetic tanning agent A IV, 30 parts of additive CI and 10 parts of NaHCO ₃ are mixed intensively at room temperature and agglomerated by adding 30 parts of polymeric retanning material B III at 80 ° C. A free-flowing granulate is obtained which is soluble in water at 45 ° C. without residue.

Example 16:

20 parts of synthetic tanning agent AI, 10 parts of synthetic tanning agent A III, 20 parts of synthetic tanning agent A IV, 40 parts of additive C II and 10 parts of NaHCO ₃ are mixed homogeneously at room temperature. 50 parts of polymeric tanning agent B II are continuously added at 60 ° C. in a mixed agglomeration apparatus. A free-flowing, storage-stable granulate is obtained which is soluble in water at room temperature without residue.

Example 17:

15 parts of synthetic tanning agent AI, 15 parts of synthetic tanning agent A III, 20 parts of synthetic tanning agent Leukotan® SD 1000 (polyacrylic acid, Rohm and Haas) 40 parts of TI additive C II and 10 parts of NaHCO ₃ are mixed homogeneously at room temperature and then at 80 ° C 60 Tl of polymeric retanning agent B II added. The paste obtained is extruded at 100 ° C. and, after cooling, provides free-flowing granules.

Examples 18-20: Use Example 18: Tanning

Skin (beef, split thickness 2.5 mm) is decalcified, stained and in the usual way with a pimple made of 6% table salt, 0.5% formic acid and 1.0% sulfuric acid adjusted to pH 2.8. At room temperature, 9% of a product is added Example 11 and tanned for 2 hours at room temperature. Then the skin Moved overnight every 60 min for 5 min and the temperature slowly to 45 ° C raised. The fleet is drained, the leather washed, and to normal business Retanned, dyed, greased and finished.

The leather obtained is softer and softer than commercially available comparison products has better scar strength, the coloring is more level.

Example 19: Retanning

Wet Blue (beef, gap thickness 1.1 mm) is in the barrel at 35 ° C in 100% liquor with 7% of a product moved according to Example 12 for 2 hours. You wash, grease 50 ° C in 100% liquor with 7% of a commercially available synthetic fat, fixed by adding 2% formic acid a little at a time and switching to normal operating conditions Way done.

Example 20: Retanning

Wet blue (beef, fold thickness 1.5 mm) is in the barrel by treatment with oxalic acid in 200% liquor adjusted to pH 3.5 and the liquor drained. Then you give at 40 ° C 150% water and 12% of an agent according to Example 15. After 60 minute 1% dye is added and dyed at 50 ° C for 90 min. You fixate through portionwise addition of formic acid, drains the liquor, washes and makes that Leather finished in the usual way.

Claims (15)

1. Solid preparations comprising

   at least one compound A), capable of raising the shrinkage temperature of an untanned pelt by at least 10°C on treatment of the pelt with a compound A) in water at a temperature of 20-50°C,

   at least one different polymeric compound B) where 10 to 80% by weight of the monomer units bear one or more C₂-C₄₀-alkyl radicals and the polymer B) contains 1 to 10 mol/kg acid groups, especially carboxyl and/or carboxylate groups, and optionally

   further additives C).
2. Solid preparations according to Claim 1, characterized in that they are granular, preferably with an average particle size of 0.5 to 5 mm.
3. Solid preparations according to Claim 1, characterized in that the compound A) is selected from the group consisting of mineral tanning materials, vegetable tanning materials, aromatic syntans and resin tanning materials.
4. Solid preparations according to Claim 1, characterized in that their residueless water solubility or emulsifability at 20°C is more than 50 g/l.
5. Solid preparations according to Claim 1, characterized in that the compound A) is a mineral tanning material, preferably a salt of trivalent chromium.
6. Solid preparations according to Claim 1, characterized in that the compound A) is an aromatic syntan, especially a condensation product of naphthalenesulphonic acid, phenolsulphonic acid, bishydroxyphenyl sulphone and/or oxyditolnenesulphonic acid and formaldehyde and/or urea.
7. Solid preparations according to Claim 1, characterized in that the polymeric compound B) is selected from the group consisting of polyacrylates (B1) and polyaspartic acids (B2).
8. Solid preparations according to Claim 1, comprising 45 to 95% by weight of at least one compound A), 5 to 50% by weight of at least one compound B), and 0 to 50% by weight of one or more additives C).
9. Solid preparations according to Claim 1, characterized in that they include neutralizers, dispersants, defoamers, hydrophobicizers and/or dyeing auxiliaries as further additives C).
10. Solid preparations according to Claim 9, characterized in that the neutralizers used are alkali metal salts of aromatic sulphonic acids, weak inorganic acids and/or mono- and dicarboxylic acids.
11. Process for producing solid preparations according to Claim 1, characterized in that the compound A) optionally in mixture with C) is admixed with an aqueous solution and/or suspension of B) and if necessary drying is carried out during or after the addition of B).
12. Use of the preparations according to Claim 1 for tanning and retanning hides or skins.
13. Process for producing leathers or furs, characterized in that pretreated hides or skins are treated with an aqueous preparation according to Claim 1 in an aqueous float.
14. Process for producing leathers or furs, characterized in that pretanned leather or furs are treated with a solid preparation according to Claim 1 in an aqueous float.
15. Leathers or furs produced using a solid preparation according to Claim 1 or obtainable by a process according to Claims 13 or 14.