Abstract: Preparation of butyl rubber based graft co-polymers from halobutyl elastomers using phase transfer catalysts in the presence of a solution of an alkali metal salt of an oxygen or sulfur nucleophile that is bound to a polymeric substrate. Graft co-polymers can be produced of a butyl polymer (isobutene-coisoprene) and polymeric substrates such as polyethylene, polypropylene, polystyrene, polybutadiene, polysilanes, polysiloxanes, polyethylene glycol, polyethylene oxide, polyphosphazenes, polyferrocenes or their hybrids.

Abstract: The present invention provides a process for preparing a filled halobutyl elastomer, which includes mixing a halobutyl elastomer with at least one mineral filler and at least one phosphine modifier and optionally curing the filled elastomer with sulfur or other curative systems. Filled halobutyl elastomers prepared according to the present invention possess improved levels of filler dispersion which results in a reduction in the hardness of the compound and an increased tensile strength.

Abstract: A composite closure with a side seal proportioning lip is disclosed, with the closure including an outer plastic closure cap, and a plastic sealing liner positioned adjacent a top wall portion of the cap. The sealing liner includes a central disc-shaped portion, and an integral relatively thick, annular sealing bead portion. The closure is thus configured to effect a "top/side seal" with an associated container. The construction includes an annular liner-retaining lip having a relatively flexible annular inner edge portion which coacts with the sealing bead portion of the liner to self-adjust and proportion the degree of sealing engagement between the sealing bead portion of the liner and the associated container.