Abstract: Protection against molecular weight depression in the polymerization reaction producing polyisobutylene rubber or butyl rubber is achieved through addition of minor amounts of certain metal alkyls, particularly the lower alkyl aluminum compounds or lower alkyl aluminum hydrides which function as buffering, neutralizing or complexing agents against polymerization poisons and extraneous catalyst activators.

Abstract: Polymerization slurries of elastomeric isoolefin homopolymers and copolymers, such as butyl rubber, in diluents such as methyl chloride are effectively stabilized against agglomeration of polymer particles through addition of minor proportions of (i) a preformed copolymer stabilizer having both a lyophobic or lyophilic portion, or (ii) an in situ formed stabilizer from a functional lyophilic stabilizer precursor capable of copolymerizing or otherwise chemically bonding with the polymer product. Agglomeration of polymer products is effectively prevented, yielding a number of significant processing advantages. The process is especially adaptable to the production of isobutylene-isoprene butyl rubber.

Abstract: Polymerization slurries of elastomeric isoolefin homopolymers and copolymers, such as butyl rubber, in diluents such as methyl chloride, are effectively stabilized against agglomeration of polymer particles through addition of minor proportions of (i) a preformed copolymer stabilizer having both a lyophobic or lyophilic portion, or (ii) an in situ formed stabilizer from a functional lyophilic stabilizer precursor capable of copolymerizing or otherwise chemically bonding with the polymer product. Agglomeration of polymer products is effectively prevented, yielding a number of significant processing advantages. The process is especially adaptable to the production of isobutylene-isoprene butyl rubber.

Abstract: Methods for producing rubbery polymers are disclosed comprising forming a slurry of such rubbery polymers, preferably butyl rubber prepared from a mixture of a C.sub.4 to C.sub.8 isoolefin and a C.sub.4 to C.sub.10 conjugated mutiolefin in a low temperature reaction zone in the presence of a Friedel-Crafts catalyst and an organic halide diluent, passing that slurry into an overflow passage for transporting the slurry to a recovery system, and injecting a mixture of a hydrocarbon liquid having a boiling point above the boiling point of the organic halide and a polar organic catalyst quenching agent into said overflow passage at a point adjacent to the outlet from the reaction zone in order to prevent continued production of polymer in the overflow passage and to maintain the overflow passage substantially free of agglomerates.