Bayer Aktiengesellschaft

Wolfgang Baade

Gabor Kaszas

Werner Obrecht

Heinrich Konigshofen

Gerd Sylvester

Gerhard Langstein

Rudolf Casper

Judit E Puskas

Christian Ohm

Kurt-Peter Meurer

Bernhard Will

Bernhard A Wolf

Hugo Zimmermann

Thomas Mulder

Roland Heinrich

Kurt P Neurer

Erhard Asch

Roland Steiger

Heinrich K Onigshofen

An improved process is provided for the bromination of isoolefin-conjugated diolefin polymers by brominating said polymer in solution in selected halogen-containing hydrocarbons as solvent. There is also provided an improved product of said process wherein the brominated polymer contains not less than 80 percent of the bound bromine atoms in a form suitable to participate in the vulcanization of the polymer and wherein not less than 70 percent of the bound conjugated diolefin units are similarly so brominated.

Polymer bromination process in solution

An improved process is provided for the bromination of isoolefin-conjugated diolefin polymers by brominating said polymer in solution in a solvent comprising a mixture of an inert saturated paraffinic hydrocarbon and an inert halogen-containing hydrocarbon. There is also provided an improved product of said process wherein the brominated polymer contains not less than 70 percent of the bound conjugated diolefin units which are brominated and also not less than 80 percent of the bound bromine atoms are in a form suitable to participate in the vulcanization of said polymer.

Polymer bromination process

An improved process is provided for the bromination of isoolefin conjugated diolefin polymers by brominating said polymer in solution in a solvent comprising a mixture of an inert saturated paraffinic hydrocarbon and an inert halogen-containing hydrocarbon. There is also provided an improved product of said process wherein the brominated polymer contains not less than 70 percent of the bound conjugated diolefin units which are brominated and also not less than 80 percent of the bound bromine atoms are in a form suitable to participate in the vulcanization of said polymer.

Gel-free ethylene/vinyl acetate copolymers with a high content of copolymerized vinyl acetate and a high Mooney viscosity are produced by carrying out the polymerization in solution in the presence of 20 to 45% by weight tert.butanol, based on the reaction solution, at temperatures of 50.degree. to 80.degree. C. and under pressures of 300 to 450 bar using azo compounds in a cascade of stirred reactors with an average residence time of the reaction solution in the reactor cascade of 5 to 9 hours and a conversion of 50 to 70% by weight, based on the vinyl acetate used. The ethylene/vinyl acetate copolymers produced by the process according to the invention may be used for the production of vulcanizates having improved mechanical properties.

Process for the production of gel-free ethylene/vinyl acetate copolymers

C.sub.4 -C.sub.16 alkyl rubbers are brominated by reacting the alkyl rubbers with bromine in the presence of organic azo compounds and/or alkali metal and/or alkaline earth metal hypochlorites and in the presence of linear, branched and/or cyclic alkanes and water at temperatures of 10.degree. to 100.degree. C., optionally under pressure, wherein the quantity of bromine is 0.2 to 1.2 times the molar quantity of double bonds contained in the rubber, 0.1 to 3 times the molar quantity of hypochlorite and/or azo compounds is used relative to the quantity of bromine used, providing that the concentration of the hypochlorites in an aqueous solution is 2 to 20 wt. %, and wherein 5 to 20 wt. % of water, 60 to 90 wt. % of alkanes and 5 to 25 wt. % of alkyl rubber are used relative to 100 wt. % of the total of alkyl rubber, alkanes and water.

Process for the bromination of alkyl rubbers

Polyisoolefins are produced according to the invention by polymerizing isoolefins having 4 to 16 carbon atoms, optionally with conjugated diolefins having 4 to 6 carbon atoms and/or cationically polymerizable, mono- or polyunsaturated, organic compounds having 4 to 16 carbon atoms in the presence of mixtures of carbon dioxide and linear, branched and/or cyclic C.sub.4 -C.sub.8 alkanes and in the presence of catalysts at temperatures of -70.degree. C. to +20.degree. C. and pressures of 1 to 70 bar, wherein the weight ratio of carbon dioxide to alkanes is 10:90 to 90:10. The process according to the invention largely prevents the formation of fouling on the reactor walls, so ensuring better removal of heat. Moreover, in accordance with the process according to the invention, the polyisoolefins obtained may be directly chemically modified once the carbon dioxide has been removed.

Process for the production of polyisoolefins

The production of C.sub.4 -C.sub.16 alkyl rubbers using the slurry process by copolymerisation of isoolefins having 4 to 16 carbon atoms with conjugated diolefins having 4 to 6 carbon atoms and/or cationically polymerisable, mono- or polyunsaturated organic compounds having 4 to 16 carbon atoms in the presence of methyl chloride and in the presence of Friedel-Crafts catalysts proceeds particularly advantageously by performing copolymerisation in the presence of linear, branched and/or cyclic alkanes.

Process for the production of C.sub.4 -C.sub.16 alkyl rubbers using the

A solution polymerisation process carried out continuously in a cascade produces high molecular weight gel-free ethylene terpolymers having on the one hand high resistance to fuels, oils and organic solvents and on the other hand high flexibility even at low temperatures when narrow ranges are adhered to in respect of solvent content, pressure, temperature control and degree of conversion.

Continuous process for the production of ethylene/vinyl ester terpolymers

Ethylene/vinyl acetate solution polymers with increased strength and low gel content may be prepared by the copolymerization of small quantities of acryloyl or methacryloyl compounds.

Process for the preparation of ethylene/vinyl acetate copolymers with

High molecular weight, gel-free ethylene/vinyl acetate copolymers may be prepared by the process of solution polymerization if a particular relationship of temperature/pressure is observed.

Growing community of inventors

Wildeshausen, Germany

Wolfgang Baade