Classifications

• • C—CHEMISTRY; METALLURGY
  • C14—SKINS; HIDES; PELTS; LEATHER
  • C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
  • C14C3/00—Tanning; Compositions for tanning
  • C14C3/02—Chemical tanning
  • C14C3/28—Multi-step processes
• • C—CHEMISTRY; METALLURGY
  • C14—SKINS; HIDES; PELTS; LEATHER
  • C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
  • C14C3/00—Tanning; Compositions for tanning
  • C14C3/02—Chemical tanning
  • C14C3/08—Chemical tanning by organic agents
  • C14C3/22—Chemical tanning by organic agents using polymerisation products

Definitions

• the main tanning is usually carried out with mineral tanning agents, such as basic chromium, aluminum and / or zirconium salts, alone or in combination with synthetic tanning agents.
• mineral tanning agents such as basic chromium, aluminum and / or zirconium salts
• a subsequent retanning with natural or synthetic tanning agents serves to improve the sensory properties of the leather, such as feel, softness, grain and fullness. So it is not a tanning in the strict sense of the word, i.e. there is generally no marked increase in the shrinking temperature of the leather.
• syntans i.e. water-soluble condensation products from e.g.
• Naphthalenesulfonic acid and formaldehyde or from phenolsulfonic acid, formaldehyde and urea also ligninsulfonic acids and, for some years now, water-soluble polymers and copolymers based on acrylic acid and other unsaturated polymerizable carboxylic acids, generally in combination with the aforementioned syntans. They are all anionic in character, which means that the dyeings are lightened to a greater or lesser extent with the usual anionic dyes.
• Tanning agents according to DE-OS 28 43 233 offer progress in this respect, in which, in contrast to conventional syntans, small amounts of aromatic amines are condensed. Although these products give the leather good coloring properties when used alone for retanning, they are not able to deepen the coloration of leather that has been retanned with conventional syntans. In addition, their filling effect is less than that of commercially available polymer tanning agents based on acrylic acid or methacrylic acid.
• the object of the invention was therefore to develop a tanning process which avoids these disadvantages, i.e. that gives the leather favorable coloring properties and a good fullness even when anionic tanning and retanning agents are used.
• the polymer tanning agent to be used according to the invention must be water-soluble, i.e. at least 2, preferably at least 10% by weight aqueous solutions should be prepared under the conditions usually present during retanning (pH 3.5 to 6, preferably 4 to 5.5; temperature 10 to 70, preferably 30 to 45 ° C.) be.
• the polymer does not necessarily have to be completely genuine (clear) in this case, a colloidal (ie more or less cloudy) solution is also sufficient. However, real solutions are preferred.
• the amount of polymer tanning agent used is 0.025 to 2.5, preferably 0.25 to 1.6%, based on the shaved weight.
• acrylic acid and methacrylic acid and maleic acid or their anhydride are particularly suitable as the monomer containing carboxyl groups.
• carboxyl groups There are also others, e.g. Itaconic acid and crotonic acid, useful.
• Itaconic acid and crotonic acid useful.
• a more or less large part of the carboxyl groups is present in salt form in aqueous solution.
• the type of cation is practically irrelevant; the most common are sodium, potassium and especially ammonium ions.
• ammonium ions are mono-, di- and trialkylammonium ions with 1 to 6 carbon atoms in the alkyl radical.
• the manner in which the amino group is attached to the polymer does not play a significant role for the purposes of the invention.
• an amino group-containing, copolymerizable monomer is polymerized in, in the other case a C 1-4 - dialkylamino-C 2-6 alkylamine is polymerized in on maleic anhydride to form the corresponding amide acid (also called half amide, because one of the anhydride group from Carboxyl and an amide group is formed).
• a dialkylaminoalkylamine it is also possible to use a C 1-4 -dialkylamino-C 2-6 -alkanol, for example 2-dimethylaminoethanol, 2-diethylaminoethanol, 2-dibutylaminoethanol, 1-dimethylamino-2-propanol, 1-dimethylamino-3- add propanol, 2,2-dimethyl-3-dimethylamino-l - propanol, analogously to the anhydride group, forming the ester acid (or also called half ester).
• Part of the maleic anhydride groups can also be reacted with ammonia, an amine or an alcohol in order to set the desired ratio of the number of carboxyl groups to that of the amino groups.
• Tertiary amino groups are preferred. If you want to quaternize them (which generally has no particular advantages), this can be done by polymer-analogous reaction of the polymer containing tertiary amino groups with conventional quaternizing agents such as dimethyl sulfate, diethyl sulfate, benzyl chloride, methyl iodide, etc., or also by quaternization of the tertiary amino group of the copolymerizable monomer containing amino groups before polymerization.
• conventional quaternizing agents such as dimethyl sulfate, diethyl sulfate, benzyl chloride, methyl iodide, etc.
• nonionic comonomers which are particularly suitable are acrylonitrile and acrylamide, but also, for example, styrene, methacrylonitrile, methacrylamide, vinyl acetate, vinyl chloride, vinylidene chloride, butadiene, ethylene, acrylic esters and methacrylic esters of alcohols having 1 to 8 carbon atoms.
• Vinyl acetate and vinyl propionate can also be used.
• the polymers are obtained in the usual way by copolymerization in aqueous or organic solution, in dispersion or in bulk with the usual free-radical initiators (e.g. peroxides, azodiisobutyronitrile).
• free-radical initiators e.g. peroxides, azodiisobutyronitrile
• the polymer has a K value according to Fikentscher (Cellulose - Chemie 13, 1932, pages 58 to 64 and 71 to 74), measured in dimethylformamide, from 15 to 80, preferably 20 to 60. The measurement is carried out at 60 ° C. in a mixture of 60 parts of dimethylformamide and 40 parts of glacial acetic acid at a concentration of 1 g / 100 ml.
• the number ratio of amino to acid groups in the polymer tanning agent according to the invention should be 1:20 to 17:20, preferably 1: 8 to 1: 2, and the carboxyl group content should be 6 to 40, preferably 12 to 30% by weight of the total Polymers.
• carboxyl groups is also intended to include carboxylate groups here.
• the retanning according to the invention can be carried out separately in a separate operation or together with the coloring and oiling. As mentioned, it is possible and even preferred to combine them with a conventional retanning, ie with anionic retanning agents, or to connect them to it.
• the polymer tanning agents to be used in accordance with the invention impart a good abundance and above all good coloring properties to the leather.
• polymeric tanning agents are usually used in combination with syntans. As a rule, it is observed that this Combination lightens the color even more than using Syntan alone.
• the polymer tanning agents according to the invention do not have this disadvantage, depending on the type of monomer containing amino groups used, it is even possible to achieve a more or less marked color deepening compared to the coloring of the leather which has only been treated with syntanes. With regard to this color-deepening effect, the polymer tanning agents according to the invention are surprisingly clearly superior to the syntanes containing amino groups known from DE-OS 28 43 233. This is particularly surprising because the number of carboxyl groups in the polymer tanning agent according to the invention exceeds that of the amino groups. In addition, there is usually a better filling effect and better light fastness.
• the starting materials mentioned in the examples, apart from the polymer tanning agents according to the invention, are commercially available.
• the polymerizations were carried out under a protective gas atmosphere (nitrogen).
• the resulting solution was used as follows for retanning: First, 100 parts falzfeuchtes chrome leather are neutralized in 100 parts of water at 30 0 C with 1 part of sodium formate and 0.4 parts of sodium hydrogen carbonate. The mixture was then drummed in 100 parts of fresh, aqueous liquor at a temperature of 40 ° C., first with 1 part of a commercially available neutralized dyeing aid based on phenolsulfonic acid for 20 minutes, after which 7 parts of tannin solution were added. After drumming for a further 40 minutes, 4 parts of a commercially available full tanning agent based on phenol were added to the liquor and drumming for a further 60 minutes. Then 1 part of the Acid Brown 161 dye was added. After drumming for a further 30 minutes, greasing was carried out with 6 parts of a commercially available fat licker based on natural fat. Finally, 1 part of formic acid was acidified.
• the leather treated according to the invention was dyed significantly deeper.
• the solution obtained was used for retanning as follows: First, 100 parts of crimped cowhide leather moistened in 100 parts of water were deacidified at 30 ° C. with 1 part of sodium formate and 0.3 part of sodium hydrogen carbonate. Subsequently, in 100 parts of fresh, aqueous liquor, it was first tumbled for 20 minutes at a temperature of 40 ° C. with 2 parts of a commercially available neutralized auxiliary tanning agent based on naphthalenesulfonic acid. Thereafter, 9 parts of the tannin solution obtained as described above were added to the liquor and drummed for a further 60 minutes. It was then colored with 1 part of Acid Brown 165 in the same liquor and then greased with 5 parts of a commercially available combination licker. Finally, it was acidified with 1 part of formic acid.
• the leather treated with the tanning agent according to the invention was again dyed significantly deeper.
• the tanning agent obtained was used according to Example 2. A very deeply colored leather was obtained.
• reaction vessel 52 parts of styrene and 49 parts of maleic anhydride were dissolved in 300 parts of dimethylformamide and heated to 85 0 C. 3 parts of AIBN were added within one hour. After a two-hour after-reaction at 85 ° C., a mixture of 45.8 parts of dibutylamine and 24.5 parts of dimethylaminopropylamine was slowly added. Thereafter, the temperature was maintained at 85 ° C. for a further hour. Then water was added and made weakly basic with NH 3 .
• the tannin solution was used according to Example 2. A deeply colored leather was obtained.
• the leather thus produced as in Example 2 was very deeply colored.
• the leather thus produced as in Example 2 was deeply colored.
• reaction vessel 27 parts of acrylic acid, 18 parts of dimethylaminopropyl methacrylamide, 65 parts of acrylonitrile, 80 parts of dimethylformamide were mixed, heated to 85 0 C and added with 4 parts of azobisisobutyronitrile over 1 hour. The inside temperature rose to 126 ° C. After post-polymerization for 0.5 hours at this temperature, the mixture was cooled and the reaction product was brought into solution with 30 parts of 20% strength aqueous NH 3 solution and 540 parts of water. A solution with a solids content of 16.5% resulted.
• the leather thus produced as in Example 2 was very deeply colored.
• the leather thus produced as in Example 2 was dyed in a full tone.
• the leather thus produced as in Example 2 was dyed in a deep tone.
• the leather thus produced as in Example 2 was dyed in a deep tone.
• the leather thus produced as in Example 2 was dyed in a deep tone.
• the leather thus produced as in Example 2 was dyed in a deep tone.
• the leather thus produced as in Example 2 was dyed a full tone.
• a reaction vessel provided with a reflux condenser and stirrer, 61 parts of acrylonitrile, 30 parts of acrylic acid, 9.6 parts of dimethylaminopropyl methacrylamide, 80 parts of dimethylformamide (DMF) and 20 parts of acetone were mixed and heated to 75.degree. Then 4 parts of AIBN were added in 4 portions within 60 minutes. After post-polymerization for one hour at 75 ° C., the reaction mixture was cooled and dissolved in a mixture of 286 parts of water and 30 parts of concentrated aqueous ammonia solution (NH 3 ). A solution with a solids content of 18.7% was obtained.
• NH 3 concentrated aqueous ammonia solution
• the leather thus produced as in Example 2 was dyed in a full tone.
• the tanning agent obtained was used according to Example 2. A deeply colored leather was obtained.
• the tanning agent obtained was used according to Example 2. A very deeply colored leather was obtained.
• Example 1 60 parts of acrylonitrile, 27 parts of acrylic acid, 23.5 parts of methacrylamidopropyltrimethylammonium chloride in 80 parts of DMF and 20 parts of acetone polymerized as in the preceding examples using AIBN and dissolved in water and NH 3 .
• a leather produced in the same way as in Example 2 was dyed in a full tone.
• the tanning agent obtained was used according to Example 2. A very deeply colored leather was obtained.
• a mixture of 17 parts of dibutylamine, 28 parts of diethylaminoethylamine and 10 parts of diethylamine was added to the solution of the styrene-maleic anhydride copolymer in DMF from Example 17, cooled to 25 ° C. After heating to 85 ° C. for two hours, the mixture was dissolved in 500 parts of water and 30 parts of NH 3 .
• the leather thus produced as in Example 2 was dyed in a full tone.
• a mixture of 34 parts of diethylaminobutylamine, 17 parts of dibutylamine and 10 parts of diethylamine was added to the solution of the styrene / maleic anhydride copolymer in DMF from Example 17, cooled to 25 ° C. After heating to 85 ° C. for two hours, the mixture was dissolved in 500 parts of water and 30 parts of NH 3 .
• the leather thus produced as in Example 2 was dyed in a full tone.
• the leather thus produced as in Example 2 was dyed in a full tone.
• the leather thus produced as in Example 2 was dyed in a full tone.
• the tanning agent obtained was used according to Example 2. A deeply colored leather was obtained.
• the leather thus produced as in Example 2 was dyed in a full tone.
• the tanning agent obtained was used according to Example 2. A deeply colored leather was obtained.
• the tanning agent obtained was used according to Example 2. A deeply colored leather was obtained.
• the leather thus produced as in Example 2 was dyed in a full tone.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Treatment And Processing Of Natural Fur Or Leather (AREA)

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• 1982
  • 1982-01-16 DE DE19823201226 patent/DE3201226A1/de not_active Withdrawn
  • 1982-12-16 EP EP82111711A patent/EP0084134B1/fr not_active Expired
  • 1982-12-16 DE DE8282111711T patent/DE3272390D1/de not_active Expired
• 1983
  • 1983-01-10 JP JP58001273A patent/JPS58125800A/ja active Granted
• 1985
  • 1985-05-10 US US06/732,808 patent/US4596581A/en not_active Expired - Lifetime

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