Bayer Aktiengesellschaft

Bernhard Wehling

Carl-Wolfgang Schellhammer

Josef Bremen

Franz Schade

Helga Rosentreter

Joachim Kochta

Bernd Makowka

Henricus Slaats

Peter Schindlmayr

Josef Muller

Wilhelm Krummel

Heinz-Gunter Klein, Deceased

Gertrud Klein, Heir

Herbert Burkhardt

Process for retanning mineral-tanned leathers, characterised in that the retanning agents used are sulphonic acids and/or salts thereof of the general formula ##STR1## wherein R represents hydrogen, --CH.sub.3 or the radicals ##STR2## X represents hydrogen, an alkali metal ion, especially sodium, potassium or lithium ion, or an ammonium ion and

Process for retanning mineral tanned leathers with aromatic sulphonic

In the production of chrome leather, a pretreatment of delimed and bated pelts with condensation products not having a tanning action leads to substrates which, without any problems, can be mechanically dewatered and shaved or split and shaved. The properties of the leathers produced therefrom by chrome tanning do not differ from those of leathers which have been conventionally chrome-tanned and shaved.

Process for producing chrome leather

Crome tanning of pickled animal hides with a tanning agent comprising a reaction product of a basic chromium (III) sulfate and aliphatic C.sub.4 -C.sub.6 dicarboxylic acids or their salts is improved by preparing the reaction product in an aqueous solution from basic chromium (III) sulfate and 0.2 to 0.8 mol of the aliphatic dicarboxylic acids per mol chromium oxide of the basic chromium sulfate with subsequent adjustment of the theoretical basicity to 0 to 50% with alkali metal hydroxide or carbonate, the reaction product being added to a hide pickling liquor in the form of an aqueous solution having a chromium oxide content of at least 5% or in powder form in a quantity of 0.9 to 1.5% chromium oxide, based on hide weight, with a liquor volume less than 100%, based on hide weight, the final pH value being above 4.0 and the final temperature above 40.degree. C.

High-extraction chrome tanning process

The present invention relates to a process for the retanning (afterchroming) of chrome leathers. It has been found very high chromium exhaustion of the liquor can be achieved if the leather is retanned with mixtures of,

Process for the retanning of chrome leathers

1,4-Bis-(4-chloro-2-methoxystyryl)-benzene is highly suitable for whitening polymeric substances, in which use it is distinguished, for example, by a good yield and a pleasant shade.

1,4-Bis-(4-chloro-2-methoxystyryl)-benzene

Process for mass-dyeing of thermoplastics, characterized in that the dyestuffs used are of the formula ##STR1## in which X designates a radical ##STR2## R designates hydrogen or alkyl, R.sub.1 and R.sub.2 designate alkyl,

Process for mass-dyeing of thermoplastics: polystyrene and styrene

Compounds of the formula ##STR1## in which R.sup.1, R.sup.2 and R.sup.3 denote hydrogen, alkyl, alkoxy or halogen,

Benzofurane benzoxazoles

Compounds of the formula ##STR1## in which R.sub.1 denotes aryl, alkyl, aralkyl, styryl or alkoxy,

Benzofuranyl-benzimidazoles

Optical brighteners of the formula ##STR1## wherein the radicals R.sub.1 to R.sub.9 are substituents customary in brightener chemistry,

Process for the preparation of benzimidazolylbenzofuranes

Compounds of the formula ##STR1## wherein R.sup.1, R.sub.2 and R.sub.3 denote hydrogen, chlorine or methyl,

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Cologne, Germany

Bernhard Wehling