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
  • C14C3/08—Chemical tanning by organic agents
  • C14C3/18—Chemical tanning by organic agents using polycondensation products or precursors thereof
  • C14C3/20—Chemical tanning by organic agents using polycondensation products or precursors thereof sulfonated
• • 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
  • C14C3/04—Mineral tanning

Definitions

• the invention relates to the use of special condensation products for retanning of iron-tanned leather, a process for retanning iron-tanned leather Leather and leather containing corresponding condensation products.
• Tanning with iron is already known cf. Stather, tanning chemistry and tanning technology, Akademie Verlag, Berlin, 1957, 474-480; Heidemann E. at al., Possibilities and limits of iron tanning, Das Leder, 1990, 8-14; Balasubramanian S. et al., Iron Complexes as Tanning Agents, JALCA, 1997, 218-224.
• the leather tanned in Heidemann was made with commercially available leather Naphthalenesulfonic acid-formaldehyde condensates (TANIGAN® BN) or Phenolic condensation products (BASYNTAN® DLX) retanned. The so obtained However, leather still leaves something to be desired in terms of its softness (see Example 7) and are not suitable for furniture leather or automotive cover leather
• the object of the present invention was therefore to provide soft iron-tanned leather.
• condensation product may consist of further Reactants in addition to A, B and optionally C was prepared.
• condensation products are only made up of A, B and possibly C.
• Phenol and formaldehyde based means that the condensate is next to phenol and formaldehyde is produced from other reactants, for example phenolsulfonic acid and urea.
• “retanning” means post-treatment from iron-tanned leather to color, levelness, softness, fullness and behavior against water (hydrophobicity) and to fix tannins.
• the iron-tanned leather is preferably also chrome-free.
• Chromium-free in the sense of the present invention does not mean with chromium salts tanned.
• the maximum amount of chromium e.g. caused by natural sources of Cr contents in animal skins or chromium-containing dyes in leather less than 2000 ppm.
• Chromium in leather is preferably less than 100 ppm.
• the leather used for retanning preferably has a shrinking temperature greater than 70 ° C, especially greater than 75 ° C.
• the iron-tanned leather also preferably has an iron content of 1 to 7 Wt .-%.
• the iron content is determined as follows: A sample of the leather becomes Preservation of the reference weight at 70 ° C in a vacuum to constant weight. Then ashed at 800 ° C, the content of Fe (III) with a commercially available Method determined by wet chemistry and calculated back to the reference weight.
• the iron content preferably results from tanning with iron salts.
• Preferred iron salts are those of iron in the +3 oxidation state, for example Iron chloride, iron sulfate, basic iron sulfate and those of iron in the Oxidation level +2 like iron sulfate. Based on the nakedness used, the is Amount of Fe (III) or Fe (II) preferably from 0.3 to 5% by weight, in particular 1 to 3% by weight.
• the use according to the invention preferably leads to leathers with a softness of greater than 15 units, preferably greater than 20, in particular greater than 30, measured according to IUP / 36, with a measuring device ST 300 from Heights Design Production Ltd., Suite, UK or an equivalent device.
• the leather obtained can improve the surface properties and physical fastness with commercially available products and machines with a polymeric film layer can be prepared, such as. B. described by W. Wenzel in Aqueos Finishing of Leather, JALCA, 1991, 442-455.
• sulfomethylated aromatics are also used as sulfonated aromatics Aromatics and biarylsulfones understood.
• Preferred sulfonated aromatics are: Naphthalenesulfonic acids, phenolsulfonic acid, sulfonated ditolyl ethers, 4,4'-dihydroxydiphenyl sulfone, sulfonated diphenylmethane, sulfonated diphenyl, sulfonated Terphenyl or benzenesulfonic acids.
• Aldehydes and / or ketones include, in particular, aliphatic, cycloaliphatic as well as aromatic in question.
• Aliphatic aldehydes are preferred, particularly preferably formaldehyde and other aliphatic aldehydes with 2 to 5 carbon atoms in Question come.
• unsulfonated aromatics are phenol, cresol or dihydroxydiphenylmethane in question.
• urea derivatives for example, dimethylol urea, melamine or Guanidine can be called.
• Phenol and phenol derivatives are common also by simultaneous exposure to formaldehyde and urea or by Dimethylolurea linked (DE-A 1 113 457). Sulfonation products more aromatic Connections are (according to Ullmann's Encyklopadie der Technische Chemie Volume 16 (4th edition) Weinheim 1979, p. 138) usually without the unreacted starting compounds separate, alone or together with other starting compounds condensed with formaldehyde.
• a solubilizing group can Phenols also by sulfomethylation under the simultaneous action of Alkali hydrogen sulfite and formaldehyde are introduced along with the condensation become. This sulfomethylation is e.g. described in DE-A 848 823.
• condensation products are condensates of ditolyl ether sulfonic acid with 4,4'-dioxydiphenyl sulfone, phenol sulfonic acid with phenol and urea.
• condensation products are those by condensation of sulfonated and optionally non-sulfonated aromatics with aliphatic Aldehydes, preferably formaldehyde, are obtained, with sulfonated Aromatics in particular no sulfomethylated aromatics are understood.
• condensation products are preferably by condensation of obtained sulfonated phenol and / or 4,4'-dihydroxydiphenyl sulfone with formaldehyde.
• the condensation product preferably obtained in the condensation has preferably a degree of condensation from 2 to 150, preferably from 2 to 20 and preferably a preferred number average molecular weight from 500 to 35,000 g / mol.
• Particularly preferred condensation products have a molecular weight of less than 3,000 g / mol.
• the condensation generally takes place at pH values from -1 to 9.
• the condensation of sulfonated and optionally non-sulfonated aromatics, where the aromatics have no hydroxyl groups is carried out with aldehydes and / or ketones, in particular an aldehyde, preferably formaldehyde and optionally urea or urea derivatives, in the acidic pH range.
• the condensation of sulfonated aromatics which carry hydroxyl groups with an aldehyde, in particular with formaldehyde is preferably carried out at pH 6-8.
• the condensation products are preferably in the form of alkali metal, alkaline earth metal or ammonium salts or a mixture thereof.
• Particularly preferred salt forms are the Na, K, Li, NH 4 , Ca, Mg or NR 1 R 2 R 3 R 4 salts, where
• R 1 to R 4 are identical or different C 1 -C 8 alkyl or C 6 -C 10 aryl radicals or H.
• the acid which may have originated from the preceding sulfonation of the aromatic and / or the acid used in the condensation reaction can preferably be completely or partially neutralized.
• a pH of 3 to 8 is preferably set. The pH is preferably adjusted so that a 1% solution has the specified pH.
• an inorganic base such as NaOH, Na 2 CO 3 , KOH, LiOH, NH 4 OH is used for this purpose.
• Aromatics are generally carried out using generally known methods, such as those used are described for example in DE-A 29 34 980.
• a suitable sulfonating agent can, for example, chlorosulfonic acid, amidosulfonic acid, oleum and sulfuric acid be used.
• the reaction mixture obtained is preferably used for the subsequent one Condensation used without intermediate isolation of the sulfonated aromatic he follows.
• the reaction mixture is preferably used without the sulfonated aromatics are separated.
• the molar ratio of phenolsulfonic acid to bishydroxyphenylsulfone is preferably 80:20 to 10:90, in particular 50:50 to 20:80.
• the mixture of phenol sulfonic acid and bishydroxyphenyl sulfone is preferred with 0.2 to 2.0 mol equivalents of formaldehyde per aromatic monomer, in particular 0.3 to 1.0 mol equivalents implemented.
• the amount of the condensation product used for retanning is preferably 1 to 20 wt .-%, in particular 2 to 10 wt .-%, based on the iron-tanned Leather.
• Iron tanning is generally carried out in such a way that the pickled nakedness is removed with a Treated with iron salt. Possible iron salts are those listed above Question.
• the tanning is preferably done in water at a temperature of 0 - 60 ° C, preferably 20-37 ° C.
• the tanning liquor After adding the iron salts for tanning, the tanning liquor should have a pH of 1.0 to 3.2, preferably from 1.4 to 2.5. After a reasonable time to penetrate from 30 min. up to 24 h, preferably 1 h to 6 h, the pH of the tanning liquor becomes Fixation of the iron salts raised.
• a basic compound e.g. B. Sodium hydroxide, carbonate, bicarbonate, formate, calcium carbonate or magnesium oxide used.
• a pH range from 3.0 to 6.0, preferably 3.1 to 4.0 should preferably be achieved.
• the iron-tanned leather thus obtained has a shrinking temperature of greater than 70 ° C, preferably greater than 75 ° C. It also has a uniform yellow color. For example, it can be mechanically aftertreated by wilting, folding, etc. on conventional tanneries.
• the method is preferably carried out by removing the bare to be tanned from the Iron tanning acid-treated, especially with an organic polycarboxylic acid.
• the preferably used pickled pelts for iron tanning are preferred acid pretreated, especially at pH 2-5, especially preferred at 3-4. This acid pretreatment is preferably decalcified and pickled nakedness used.
• Compounds such as carboxy acids are particularly used for pimples such as formic acid, acetic acid or oxalic acid or inorganic acids such as sulfuric acid or acidic salts of sulfuric acid or mixtures thereof.
• non-polymeric acids are difunctional carboxylic acids such as Succinic acid, maleic acid, glutaric acid and / or adipic acid; trifunctional carboxylic acids such as citric acid or polymeric carboxylic acids such as (co) polymerized Products using (meth) acrylic acid, maleic acid or itaconic acid or their derivatives.
• difunctional carboxylic acids such as Succinic acid, maleic acid, glutaric acid and / or adipic acid
• trifunctional carboxylic acids such as citric acid or polymeric carboxylic acids such as (co) polymerized Products using (meth) acrylic acid, maleic acid or itaconic acid or their derivatives.
• These acids are preferably obtained in an amount of 0.5 to 10% by weight used on the nakedness used, in particular 1-4 wt .-%.
• the acidic pretreatment preferably proceeds in such a way that pimples are added to the nakedness used be given in an amount so that the pH of the pickled bare on a value of 2-5, in particular reduced to 3-4.
• the pimple connections are preferably added to the nakedness in a tanning drum in aqueous solution. This is generally done at a temperature of 0 to 60 ° C, especially at 20 to 37 ° C. It is preferably 10 min. up to 24 h, especially 30 min. up to 2 h pretreated.
• a fatty agent is particularly preferably added to the acidic pretreatment.
• Preferred lubricants for this use are as an emulsion or solution in water stable against low pH values and high electrolyte concentrations.
• the water content of the iron-tanned leather preferably reduced by withering, and then the thickness of the leather corrected by folding if necessary.
• the retanning process is preferably carried out in a tanning drum in an aqueous liquor Temperature from 0 to 70 ° C, especially from 20 to 50 ° C instead and includes optional in addition to the condensation products according to the invention, further aids such as e.g. Polymers, fatliquors, colorants, acids and bases.
• Preferred lubricants for this use are e.g. B. sulfonated, sulfated or sulfited fats, e.g. B. long-chain alkanes, alcohols, carboxylic acids or esters natural or synthetic origin, e.g. B. fish oils, claw oils, vegetable oils or synthetic oils.
• the dyes are generally to make water-soluble solutions common in leather applications Dyes, e.g. B. those from the groups of acid dyes, direct dyes, Metal complex dyes or substantive dyes.
• the preferred polymers for use are high molecular weight water soluble or water dispersible products e.g. B. from the (Co) polymerization reaction of unsaturated acids and their derivatives with z. B. more filling or greasy effect on leather.
• Acids and bases are used to change the pH of the aqueous liquor to influence the penetration properties of the compounds used or to fix them.
• the condensates used according to the invention are preferably in 20 to 1000, preferably 50 to 200% aqueous liquor based on the weight of the used Leather used in a pH range from 3.0 to 8.0, preferably 3.5 to 6.5.
• the Addition of 1 - 20%, preferably 2 - 10% of the products can be in one or also take several steps. Other tools can also be used added in one or more steps, together with or separately of the products according to the invention.
• the retanning process is carried out in 1 - 48 h, preferably in 1.5 - 24 h, especially in 2 - 8 h.
• the leather according to the invention preferably has a softness of greater than 15 Units measured according to IUP / 36, preferably greater than 20, in particular greater than 30 units.
• the brilliant blue leather thus obtained is hanging dried, air-conditioned, placed and milled.
• IUP / 36 softness 55 units

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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)
• Phenolic Resins Or Amino Resins (AREA)

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• 2002
  • 2002-10-28 DE DE10250112A patent/DE10250112A1/de not_active Withdrawn
• 2003
  • 2003-10-15 EP EP03023286A patent/EP1416058A1/fr not_active Withdrawn
  • 2003-10-24 ZA ZA200308303A patent/ZA200308303B/xx unknown
  • 2003-10-27 JP JP2003366261A patent/JP2004149797A/ja not_active Withdrawn
  • 2003-10-27 US US10/694,382 patent/US20040148707A1/en not_active Abandoned
  • 2003-10-27 MX MXPA03009857A patent/MXPA03009857A/es not_active Application Discontinuation
  • 2003-10-27 KR KR1020030074985A patent/KR20040038694A/ko not_active Application Discontinuation
  • 2003-10-28 AR ARP030103933A patent/AR041845A1/es unknown
  • 2003-10-28 CN CNA2003101046451A patent/CN1498974A/zh active Pending
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