Process for production of butyl rubber
The present invention relates to a process for producing polymers containing repeating units derived from at least one isoolefin monomer, optionally repeating units derived from at least one multiolefin monomer and optionally further copolymerizable monomers in the presence of a zinc compound and optionally an organic halide activator.
1. A process for producing polymers comprising repeating units derived from at least one isoolefin monomer, optionally repeating units derived from at least one multiolefin monomer and optionally further copolymerizable monomers comprising polymerizing at least one isoolefin monomer, optionally repeating units derived from at least one multiolefin monomer and optionally further copolymerizable monomers in the presence of a zinc compound wherein the zinc compound comprises a Lewis acidic zinc metal centre bonded to two identical or different C 1 to C 50 hydrocarbon radicals which may be linear, branched or cyclic and may contain one or more non-carbon atoms in the carbon-chain at least one of which is electron withdrawing.
2. A process according to claim 1 , wherein the zinc compound comprises aryl groups or substituted aryl groups.
3. A process according to claim 1 , wherein said isoolefin monomer is isobutene.
4. A process according to claim 1 , wherein the process is conducted in the presence of at least one activator of the general formula R 3 CX (I) or RCOX (II) with each R independently being a C 1 to C 50 hydrocarbon radical which may be linear, branched or cyclic and may contain one or more non-carbon atoms in the carbon-chain and each X being a halogen.
5. A process according to claim 1 , comprising polymerizing isobutene and isoprene and optionally further copolymerizable monomers.
6. A process according to claim 1 , wherein said process is a slurry polymerization.