Bayer Aktiengesellschaft

Polysar Limited

Polysar Rubber Corporation

Gabor Kaszas

Wolfgang Baade

Heinrich Konigshofen

Judit E Puskas

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.

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

An elastomeric polymer composition that exhibits improved processability and green strength comprises: from about 95 to about 70 parts by weight of one rubbery polymer selected from the group consisting of butyl rubber, chlorinated butyl rubber and brominated butyl rubber and from about 5 to about 30 parts by weight of a block copolymer having an elastomeric polyisobutylene midblock and two plastomeric endblocks of polymerized monovinylidene aromatic monomers and star-shaped block copolymers having from three to six arms wherein the inner elastomeric blocks are polyisobutylene and the outer plastomeric blocs are polymerized monovinylidene aromatic monmers for a total of 100 parts by weight of the rubbery polymer and the block copolymer. Vulcanizates of the composition that exhibit reduced permeability to gases and improved tear strength are provided together with a process for their production.

Compositions of butyl elastomers and block copolymers of polyisobutylene

A polymerization process is provided for producing a butyl rubber with a bimodal molecular weight distribution which comprises introducing isobutylene, a conjugated diolefin monomer having from 4 to 8 carbon atoms, from about 1.times.10.sup.-5 to about 1.times.10.sup.-3 moles of an initiator component per mole of isobutylene, said initiator component being selected from the group consisting of an initiator component having the formula: ##STR1## in which R.sub.1, R.sub.2 and R.sub.3 are selected from the group consisting of alkyl, aryl and aralkyl groups and can be the same or different and i is a positive whole number from 2 to 6, and an initiator component having an adamantyl nucleus bearing from 2 to 4 hydroxyl groups an inert organic solvent and from about 1.times.10.sup.-4 to about 1.times.10.sup.-3 moles of water per liter of inert organic solvent into a suitable reaction vessel at a temperature of from about -120.degree. C. to about -50.degree. C., adding a solution of from about 5.times.10.sup.-5 to about 1.times.10.sup.-2 moles of a Lewis acid per mole of isobutylene in an organic solvent and polymerizing the monomers to form said butyl rubber.

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Corunna, Canada

Gabor Kaszas