Hoechst Aktiengesellschaft

Other

3m Innovative Properties Company

Hochst Aktiengesellschaft

Axiva Gmbh

Dyneon Gmbh & Co. Kg

Bernd Felix

Klaus Hintzer

Gernot L Ohr

Tilman C Zipplies

Thomas Kaiser

Gernot Lohr

Stephan F&uuml;hrer

Thomas Sch Ottle

Armin Budesheim

Reinhard Albert Sulzbach

Walter Frohlich

Hans-Joachim Semmler

Rolf Hengel

Herbert Strasser

Ulrich Reiff

Hans-Bodo Richter

Heiner Katzenberger

Willibald Hofmeister

Hermann Bl Adel

Wolf D Mitterberger

Hagen Kniep

Tilman Zipplies

Stephan Fuhrer

Fluorinated emulsifier acids can be isolated from wastewater by firstly removing fine solids and/or material which can be converted into fine solids from the wastewater, preferably by precipitation, subsequently bringing the wastewater into contact with an anion-exchange resin and eluting the adsorbed emulsifier acids from the latter.

Method for recovering fluorinated alkanoic acids from waste waters

The invention relates to a method for removing fluorinated emulsifying agent acids from waste waters, characterized in that the finely dispersed solids in the waste water are stabilized with a nonionic or cationic surfactant or an analogous acting surface active substance, the fluorinated emulsifying agent acids are subsequently bonded on an anion exchange resin and the fluorinated emulsifying agent acids are eluted from the latter.

Process for the recovery of fluorinated alkandic acids from wastewater

An apparatus suitable in particular for degassing fluoropolymers which have been subjected to thermal degradation contains--in the direction of flow of the product--a product intake, a coolable conveyor section, a comminution apparatus, a heated conveyor section and a product discharge, the entire apparatus being designed to be gastight and advantageously being designed to be resistant to pressure surges and having a gas outlet in the area of the coolable conveyor section and/or in the area of the comminution apparatuses.

Degassing apparatus and use thereof

If the employment of polymerization auxiliaries in ammonium form is avoided in the preparation of a polytetrafluoroethylene having a content of 0.02 to 1% by weight of units of a perfluoro-(alkyl vinyl) ether by the suspension process, a polymer which does not tend to discoloration on heating is obtained.

Process for the preparation of modified polytetrafluoroethylene and its

Aqueous dispersions of fluoropolymers which are obtained by emulsion polymerization, are not processsable from the melt and form a film on sintering, which comprise a fluoropolymer A) having an average particle size (number average) of from 180 to 400 nm and a fluoropolymer B) having an average particle size which is lower by a factor of from about 0.3 to about 0.7, so that the total dispersion has a non-monomadal number distribution of the particle diameter, are suitable for soaking, impregnating or coating surfaces, for example of fibers or planiform articles of fibers or porous materials, in particular for coating fiberglass fabrics, and also for the formulation of metal coating systems.

Aqueous dispersion of fluoropolymers, its preparation and use for

Process for the preparation of a modified polytetrafluoroethylene and

Polymerizing tetrafluoroethylene with modifying amounts of a perfluoro(alkyl vinyl ether) at temperatures below 60.degree. C. using permanganate or similar initiators by the suspension process and milling the raw polymer to an average particle size of from 10 to 50 .mu.m gives molding powders which are suitable for the preform free-sintering technique.

Preparation of a modified polytetrafluoroethylene and use thereof

In the suspension polymerization of tetrafluoroethylene a mixture of tetrafluoroethylene and an inert gas is charged under pressure before starting the polymerization, the total pressure being 5 to 50 bar and the concentration of tetrafluoroethylene in this mixture being 30 to 70 mol %. Said concentration is kept within this range by an appropriate feed of tetrafluoroethylene during the polymerization. The granular PTFE powder obtained is distinguished by an improved grain structure and grindability.

Process for the preparation of tetrafluoroethylene polymer in aqueous

A process for the thermal cleavage of 1,2-dichloroethane to give vinyl chloride at 300.degree. to 600.degree. C. under atmospheric pressure or elevated pressure is described. Before cleavage of the 1,2-dichloroethane, 0.001 to 5% by weight of trichloroacetyl chloride or a compound which contains 3 carbon atoms, at least 6 chlorine atoms, 0 to 1 oxygen atom and, for each carbon atom bonded to the latter, 0 or 1 hydrogen atom, is added to it. Due to the addition of the compound(s) mentioned, the conversion is increased at the same cleavage temperature, or the cleavage temperature is reduced at the same conversion, at the same time a reduction in interfering byproducts being observed.

Process for the thermal cleavage of 1,2-dichloroethane

Perfluoroethyl iodide is prepared from an agitated mixture of tetrafluoro-diiodoethane and hydrogen fluoride by means of electrolysis. Preferably the temperature is in the range of from -15.degree. C to +19.degree. C and the voltage in the range of from 4 to 6 V.

Process for the preparation of perfluoroethyl iodide

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Burgkirchen, Germany

Bernd Felix