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. Subsequent retanning with natural or synthetic tanning agents serves to improve leather properties such as feel, softness, grain and fullness.
• mineral tanning agents such as basic chromium, aluminum and / or zirconium salts alone or in combination with synthetic tanning agents.
• synthetic tanning agents serves to improve leather properties such as feel, softness, grain and fullness.
• syntans i.e. water-soluble condensation products from e.g. B.
• the invention was therefore based on the object of developing a copolymer which, when used alone or in combination with the otherwise customary anionic condensation products (syntans) and polymers, improves the dyeing properties in the sense of less shade brightening when using anionic dyes.
• the copolymer contains 20 to 80, preferably 40 to 60% by weight of acrylamide or methacrylamide and 80 to 20, preferably 60 to 40% by weight, based in each case on the polymer, of the monomer containing an amino group and copolymerizable in aqueous solution (component b of claim 1).
• Acrylamide is preferred as component a over methacrylamide.
• component b come e.g. into consideration the methacrylic esters and preferably the acrylic esters of diethylamino or preferably dimethylamino-ethanol, -propanol or -2,2-dimethylpropanol. Dimethylaminoethyl acrylate is preferred.
• Amino-C2-5-alkyl (meth) acrylamides e.g. N- (3-Dimethylaminopropyl) methacrylamide, very suitable.
• Possible components c include: acrylonitrile, vinyl pyrrolidone, acrylic acid, methacrylic acid, maleic acid, itaconic acid, crotonic acid. Vinylpyrrolidone and acrylic acid are preferred. They are polymerized in amounts of 0 to 20, preferably 0 to 5,% by weight. The polymerization is carried out in the customary manner (as described, for example, in Ullmann, Enzyclopadie der industrial chemistry, 4th edition, volume 19, for example on pages 3 ff. And 385 ff.) In aqueous solution according to the radical mechanism.
• the K values (cf. H. Fikentscher, Cellulose-Chemie 13, 1932, pages 58 to 64 and 71 to 74), measured in one percent neutral, aqueous solution at 20 ° C., should be in the "Range from 20 to 150, preferably 20 to 130.
• Products with K values of 50 to 130 are particularly suitable for improving the coloring properties, products with K values of 20 to 80, preferably 20 for improving the fullness and softness to 50. If you want to improve both, it is therefore expedient to use a polymer with a very broad molecular weight range or else two polymers with different molecular weights simultaneously or in succession.
• the copolymers to be used according to the invention are obtained in the customary manner by polymerization in aqueous or organic solution or in dispersion with the customary free-radical initiators (for example peroxides, azodiisobutyronitrile, etc.). They can be used alone, but preferably together with other conventional retanning agents of the type mentioned at the outset.
• the amount used is 0.025 to 1, preferably 0.1 to 0.4% by weight, based on the shaved weight. If it is primarily about improving the fullness and softness, relatively large amounts (0.2 to 1, preferably 0.3 to 0.4%) are required.
• coloring properties e.g. in the case of leather retanned with an anionic tanning agent, amounts in the lower range mentioned, ie 0.025 to 0.2%, are sufficient.
• the retanning according to the invention is carried out between the main mineral tanning and the dyeing of the leather. It can be done separately in a separate operation or together with the greasing. As said, 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 colors are even.
• the dye is fixed better so that migration no longer occurs when drying.
• the polymer can also be used after dyeing, specifically for this latter purpose. If the dye bath is not yet exhausted, the liquor must be changed, otherwise precipitation can be expected.
• the liquor length in conventional as well as in retanning according to the invention is 30 to 300, preferably 100 to 150%, based on the fold weight.
• the temperature is usually 20 to 60, preferably 30 to 40 ° C, the pH 3 to 6, preferably 3.5 to 5, the treatment time is of the order of one to several hours.
• the water solubility of the polymers to be used according to the invention decreases with increasing molecular weight.
• it should be at least 2, preferably at least 10,% by weight under the abovementioned conditions customary in tanning or retanning (20 to 60 ° C. at pH 3 to 6).
• 10% by weight aqueous solutions of the polymers are generally still pourable.
• the polymer does not necessarily have to be completely real (clear) solution (although this is preferred), a colloidal (i.e. more or less cloudy) solution is also sufficient.
• the starting materials mentioned in the examples, apart from the polymer tanning agent according to the invention, are commercially available.
• the leather produced shows a greater fullness than that obtained according to Example 2 with the same softness and somewhat darker aniline color.
• a leather with a deeper color than that of Examples 2 to 4 is obtained, while the grip and fullness of the leather are influenced only to a minor extent.

Landscapes

• 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)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6144438

Family Applications (1)

Country Status (2)

Cited By (3)

Families Citing this family (2)

Citations (2)

• 1981
  • 1981-10-20 DE DE19813141496 patent/DE3141496A1/de not_active Withdrawn
• 1982
  • 1982-10-07 EP EP82109283A patent/EP0077495A1/fr not_active Withdrawn

Patent Citations (2)

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