US3101237A - Process for the retanning of mineraltanned leathers - Google Patents

Process for the retanning of mineraltanned leathers Download PDF

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Publication number
US3101237A
US3101237A US93863A US9386361A US3101237A US 3101237 A US3101237 A US 3101237A US 93863 A US93863 A US 93863A US 9386361 A US9386361 A US 9386361A US 3101237 A US3101237 A US 3101237A
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Prior art keywords
retanning
leathers
water
products
tanned
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US93863A
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English (en)
Inventor
Luck Wolfhard
Mauthe Gustav
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Bayer AG
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Bayer AG
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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
    • 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
    • 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

Definitions

  • the present invention relates to and has as its objects a retannin g process for mineral tanned leathers and is concerned with the use of water-soluble to dispersible compounds for this purpose, which are formed from phenol-resins or polyhydric phenols by substitution of the phenolic hydroXyl-groups by radicals of the general formula or also possibly partially by radicals of the general formula J O-(R-O-) H and/or O(R--O) CO-
  • R stands for an aliphatic hydrocarbon radical preferebly of 2-3 carbon atoms
  • R stands for an aliphatic or aromatic hydrocarbon radical
  • R stands for a radical same as R but preferably for an aliphatic hydrocarbon radical with at least 8 carbon atoms,
  • x stands for a whole number bet-ween 1-10, preferably between 1-3, y stands for 1 or 2 and Me is an alkalirnetal, ammoniumor an amine-cation.
  • pretanned leathers before, during or after the treatment of the pretanned leathers, when treating them further in the inventive way.
  • the products according to the present invention are not tanning materials as such or in the sense of a vegetable or synthetic tanning material. They are only useful for the treatment of leathers, preferably of mineraltanned leathers.
  • inventive treatment the character of leathers may be changed advantageously which is not or only difiicultly possible with'usual vegetable or synthetic tannin-g materials. But even if the change of the character of the leather by such inventive treatment is different from the type obtained by retanning with vegetable or synthetic tanning materials, we shall call also the inventive treatment a retanning process.
  • non-esterified carboxylic groups and of which the alkali metalor ammonium salts are water-soluble, rece'ntlybecame known as auxiliary agents for textiles.
  • these products are not at all or only very little suitable. It was not to be expected therefore, that the inventive products which contain aliphatic alcohols of certain aromatic radicals are suitable for the rctanning of leather.
  • the inventive products for a retanning process can be produced in ways known in principle.
  • Phenol-resins or polyvalent phenoles in the meaning of this invention especially may be:
  • Aromatic nuclei which are connected with other aromatic compounds in different ways by different bridges and which contain at least one phenolic hydroxyl-group per aromatic radical, eag. novolaks, dihydroxy-diphenylsulfone, and the like.
  • novolaks especially those from phenol or substituted phenols and 0.5-0.8 mol formaldehyde per mol of phenol used, and bisphenols such as dihydroxydiphenyl methane, 4.4 dihydroxy diphenyl-dimethyl-methane or dihydroxy-diphenyl-sulfone.
  • the present invention also includes products which can be obtained from polyvalent phenols, as they are formed, e.g., by combining 2 mols of 4.4-dihydroxy-diphenyldimethyl-methane by 1 mol of epichloro-hydrine or by combining severalphenol molecules with sul-fone-, sulfonamide, carbonyl-, urethaneor urea-groups.
  • the inventively modified phenol-resins or polyhydric phenols may be obtained by known methods eg. by reacting the aforesaid novola-ks or bisphenols with alkylene oxides, such as ethylene-oxide, propylene-oxide, butyleneoxide, or styrene-oxide or with chlorohydrines, such as ethylene chlorohydrine, propylene chlorohydrine or higher alkylene-chlorohydrines and by a following condensation thereof with polyhydric organic acids.
  • alkylene oxides such as ethylene-oxide, propylene-oxide, butyleneoxide, or styrene-oxide
  • chlorohydrines such as ethylene chlorohydrine, propylene chlorohydrine or higher alkylene-chlorohydrines
  • Very suitable products are obtainable from novolaks or bisphenols of which the phenolic hydroxyl-groups are substituted by the radicals
  • the starting materials for the production of very effective retanning materials are obtained by the reaction of novolaks or bisphenols according to known methods with about 1.2-2.0 mols of ethyleneor/and propylene-oxide per OH-equivalent of the phenolic compounds.
  • Other suitable products are also obtainable by the condensation of arylhyclroxy alkanols, e.g.
  • phenoxyethanol With an aqueous formaldehyde solution in the presence of acidic J) oxides are reacted with phthalic anhydride or with maleic anhydri-d-e by melting them together whereby acidic phthalic acid or maleic acid esters are obtained.
  • Suitable retanning materials are obtained by esteri-fying all or only a part of the OH-groups of such modified phenolresins with the aforesaid polyhydric organic acids.
  • Retanning materials according to the present invention are also obtained by reacting part of the OH-groups of the modified phenol-resins or polyhydric phenols with monowalent organic acids, especially with long chain acids such as :stearic-, palmiticor oleic acid. Preferably a larger part however should be reacted with polyhydric organic acids.
  • ester-ified products should contain an essentially great number of free, non-esterified carboxylic groups, so that they may be soluble in water or at least dispersible in form of their alkali metal-, ammoniumor amine-salts and it is especially suitable to use these alkali metal salts, especially the sodium or the potassium salts, as well as the ammonium salts of the inventive condensation products for the retanning process.
  • the retanning materials useful according to the present invention if they do not contain any other water-solubilizing groups beside the camboxyl groups, as e.g. sulfonic acid radicals, are precipitated from their aqueous solutions with acids or acidic reacting metal salts, as e.g. the chromium-, aluminumor zirconium salts, in aqueous solutions.
  • acids or acidic reacting metal salts as e.g. the chromium-, aluminumor zirconium salts
  • the condensation products according to the present invention are suitable for retanning of mineral tanned leathers, especially of leathers, which were tanned with chromiumor/and aluminium tannics.
  • the retanning of the leathers is carried out according to methods known in the art, e.g. by milling the leather with an aqueous solution of the condensation products in the drum.
  • Theretanning is preferably carried out at room temperature, but possibly sometimes also at a higher temperature, e.g. between about 50-60 C.
  • Retanning may also be carried out sometimes with the inventive condensation products in powder :form, i.e. without water by milling the wet raw leathers.
  • Usually about 1-6 parts by weight of the inventive products are used per 100 parts by weight of wet leather.
  • the acidity of the leather is usually suflicient if the pH-value is less than 7 and preferably is about 4.5-6.0 after the retanning process.
  • the quantity of the acid or of the acidic compounds which may be added to the tanning liquor afiter or during the ret-anning is preferably calculated so that the pH-rate of the retanning liquor is adjusted at the end of the retanning to a degree where the inventively used retanning products are completely or almost completely precipitated. This usually is the case at a pH-rate of the tanning liquor of 4.5-5.5.
  • condensation products useful according to the present invention also may be used together with anionic or non-ionic tanning, retanning or resin-tanning materials or other impregnating materials as well as dyes. Also the retanning process may be carried out in combination with the treatment of the leathers with known cationic, anionic or non-ionic tanning, retanning or resin-tanning materials. 1
  • Example 1 100 parts by weight of chromium-tanned calf-leather, which has an average pH of about 3.8, is milled in a drum with about 250 parts by weight of water at -35 4 C. and with 0.4-0.6 part by weight of sodium bicarbonate.
  • the consumption of the liquor may be seen from the degree of precipitation or turbidity after the addition of acid to the liquor.
  • After milling for about 45-75 minutes usually most of the product is taken up by the leather.
  • the remaining liquor which shows a pH value of 5.3-5.8 is removed.
  • After washing the leather with luke warm water of about 50-'60 C. it may be dyed in a new dye-bath in the usual manner, it then is greased and completed in the usual Way. There is obtained a full and tight grain leather, which distinguishes itself by a line grain, light color and very good light resistance.
  • the product used for the retanning can be obtained in the following manner:
  • an anhydrous, ethoxylated novolak which is obtainable by reaction of about parts by weight of a novolak obtained in the presence of an acidic condensation material from phenol and formaldehyde in a molar proportion of about 121.55 with about 60 parts by weight of ethylene oxide, are heated to about C.
  • 150 parts by weight of phthalic acid anhydride while stirring.
  • the mixture thereby is kept at a temperature of -l25 C. for half an hour.
  • After cooling the clear melt to about 100-105 C. there is added slowly while stirring a warm solution (of about 30 C.) of 54 parts by weight of sodium carbonate in 180 parts by weight of water.
  • Example 2 Retanning is carried out as described in Example 1, but using instead of the retanning-material mentioned therein 6-10 parts. by weight of a 50% aqueous solution of the compound of the following formula ('JOONH4 (cum-o- @w-omcmo-o 0Q] 2 There are obtained very full and light leathers of excellent quality. The color of the leather is the lighter the more the leather contained acids before retannin-g and the smaller therefore the quantity of employed bicarbonate was.
  • 'JOONH4 cum-o- @w-omcmo-o 0Q] 2
  • Example 3 100 parts by weight of a neutralized calf-leather tanned with commercial chromium or aluminium-tanning-materials and which shows an average pH of about 5.5 is washed with water of a temperature of'50 C. Thereafter it is milled for about 30 minutes in a drum with about parts by Weight of water of a temperature of 50 C. and 8-10 parts by weight of an about 50% aqueous solution of retanning material obtained in the manner described below.
  • the product used as a retanning-material is prepared as follows: HO-Q-OEQOH A novolak produced in the usual and known way in the presence of hydrochloric acid from o-cresole and C1 C1 formaldehyde in a proportion of 1:0.6 mol are further 5 reacted in usual manner in the presence of a catalytic amount of sodium hydroxide with about 1.2-1.3 mols or I propylene oxide per OH-equivalent of the novolak. The reaction product then is melted with 1 mol of H H o11 maleic acid anhydride per OH-equivalent of the o-xalkylated novolak at 120 C. for about 30 minutes. After cooling to about 100 C.
  • reaction product is diluted with a concentrated ammonia-solution.
  • the yellowa I brownish clear solution then is further diluted with water OH 7 to a concentration of about 50% and brought to a pH 15 of about 7.5 (1: 10 diluted with water) by adding further amounts of ammonia, if necessary.
  • esterified glycoland poly-glyool-esters examples for the second pant of the molecule which gives useful pnoducts in the meaning of this invention the following esterified glycoland poly-glyool-esters may be mentioned:
  • the two last mentioned groups of compounds should be present only in such an amount that'the resulting mixture does not become water insoluble or non-dispersible.
  • the amount of the last two classes of substituents of the OH-group should not exceed 50-70%, but as it is easily to be seen for a person skilled in the art, the amount of the last two classes of substituents largely depends on the nature of the before-mentioned esterified poly-glycol ethers containing carboxylic groups or their salts respectively.
  • a process for the retanning of mineral-tanned leathers which comprises treating such leathers with water-soluble to water-dispcrsible compounds which are formed by substituting the phenolic hydroxyl groups of a member selected from the group consisting of a polyhydric phenol, a polyphenol, and a novolak by a radical selected from the group consisting of (a) a radical of the formula:
  • 'R stands for a member selected from the group consisting of an aliphatic radical of 2-5' carbon atoms and a phenyl-substituted derivative of an aliphatic radical of 2-5 carbon atoms
  • R and R" represent a member selected from the group consisting of an aliphatic radical of up to 20 carbon atoms and a phenyl group
  • x is a whole number between 1 and 10
  • y is a number from 1-2
  • Me is a member selected from the group consisting of an alkali metal and an ammonium group.
  • a process for the retanning of mineral-tanned leathers according to claim 1 which comprises treating such leathers with those compounds of claim 1 in which the phenolic part of the molecule is a dihydric phenol.
  • a process for the retanning of mineral-tanned leathers according to claim 1 which comprises treating such leathers with those compounds of claim 1. in which the phenolic part of the molecule is a novolak containing up to 5 phenolic nuclei.
  • a process for the retanning of mineral-tanned leathens according to claim 1 which comprises treating such leathers with those compounds of claim 1 in which the alkylene oxide bridge of the molecule consists of 1-3 ethylene oxide molecules.
  • a process for the retanning of mineral-tanned leathers according to claim 1 which comprises treating such leathers with those compounds of claim 1 in which the alkylene oxide bridge of the molecule consists of 1-3 propylene oxide molecules.
  • a process for the retanning of mineral-tanned leathers according to claim 1 which comprises treating such leathers with those compounds of claim 1 in which the acid part of the molecules is phthalic acid.
  • a process for the retanning of mineral-tanned leathers according to claim 1 which comprises treating such leathers with those compounds of claim 1 in which the acid part of the molecules is terephthalic acid.
  • a process for the retanning of mineral-tanned leathers according to claim 1 which comprises treating such leathers with those compounds of claim 1 in which the acid part of the molecule is maleic acid.

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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)
US93863A 1960-03-09 1961-03-07 Process for the retanning of mineraltanned leathers Expired - Lifetime US3101237A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEF30720A DE1233975B (de) 1960-03-09 1960-03-09 Verfahren zum Nachgerben von mineralisch gegerbten Ledern

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US (1) US3101237A (de)
CH (1) CH413205A (de)
DE (1) DE1233975B (de)
GB (1) GB922449A (de)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2626430C2 (de) * 1976-06-12 1982-06-03 Bayer Ag, 5090 Leverkusen Verfahren zum Gerben von Leder und Gerbmischung

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB818218A (en) * 1955-10-04 1959-08-12 Bayer Ag A process for the production of cured epoxide resins
GB820991A (en) * 1956-06-11 1959-09-30 Devoe & Raynolds Co Improvements in epoxide resins
US2955013A (en) * 1957-09-12 1960-10-04 Bayer Ag Process for tanning leather with waterinsoluble condensation product of a phenol, formaldehyde, and carboxylic acid
US2965608A (en) * 1956-04-12 1960-12-20 Shell Oil Co Ethers of epoxy-substituted polyhydric phenols and their polymers
GB857073A (en) * 1955-12-19 1960-12-29 Minnesota Mining & Mfg Improvements in epoxy resin compositions

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE970324C (de) * 1952-01-19 1958-09-11 Bayer Ag Verfahren zur Herstellung von Kondensationsprodukten
DE970611C (de) * 1952-02-28 1958-10-09 Bayer Ag Verfahren zur Herstellung von Kondensationsprodukten
DE970216C (de) * 1953-03-26 1958-08-28 Bayer Ag Verfahren zum Nachgerben von Leder
DE1007013B (de) * 1954-12-06 1957-04-25 Bayer Ag Verfahren zur Herstellung von Leder

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB818218A (en) * 1955-10-04 1959-08-12 Bayer Ag A process for the production of cured epoxide resins
GB857073A (en) * 1955-12-19 1960-12-29 Minnesota Mining & Mfg Improvements in epoxy resin compositions
US2965608A (en) * 1956-04-12 1960-12-20 Shell Oil Co Ethers of epoxy-substituted polyhydric phenols and their polymers
GB820991A (en) * 1956-06-11 1959-09-30 Devoe & Raynolds Co Improvements in epoxide resins
US2955013A (en) * 1957-09-12 1960-10-04 Bayer Ag Process for tanning leather with waterinsoluble condensation product of a phenol, formaldehyde, and carboxylic acid

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CH413205A (de) 1966-05-15
GB922449A (en) 1963-04-03
DE1233975B (de) 1967-02-09

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