The West Company

Ghawamedin Bayan

Anthony S Esposito

Malcolm A Smook

Richard H Lusch

Charles H White

A molded thermoplastic elastomer having a compression set less than about forty percent, an oxygen transmission rate of less than 500 cc/m.sup.2 /day, a moisture vapor transmission rate of less than 2 gm/m.sup.2 /day, and a needle penetration force of less than 2000 grams.

Molded thermoplastic elastomer

A method of making a thermoplastic elastomer composition produced by dynamic vulcanization of SBR as a dispersed phase of cross linked SBR, and a co-continuous matrix of SEBS and polypropylene. The dynamic vulcanization step takes place under conditions of shear and temperature to reach the decomposition point of crosslinked SBR, at which time the crosslinking reaction is quenched. Compositions of superior properties are achieved using this method.

Method of making SBR thermoplastic elastomers

A thermoplastic elastomer composition is possible which has low coefficient friction, reduced stickiness and good structural integrity. A halobutyl rubber is cured by dynamic vulcanization in the presence of sufficient thermoplastic material to function as a continuous phase for the vulcanization. Thereafter, up to 25 parts based on 100 parts of the rubber of an uncured organopolysiloxane grafted EPDM polymer are admixed to form the final moldable product, resulting in a mixture which has good structural integrity and a smooth finished surface.

Modified halobutyl thermoplastic elastomer

A molded pharmaceutical primary closure including a thermoplastic elastomer molded into the shape of a closure and having a compression set less than about forty percent, an oxygen transmission rate of less than 500 cc/m.sup.2 /day, a moisture vapor transmission rate of less than 2 gm/m.sup.2 /day, and a needle penetration force of less than 2000 grams.

Molded pharmaceutical primary closure

A thermoplastic elastomer composition produced by dynamic vulcanization of SBR has a dispersed phase of cross linked SBR, and a co-continuous matrix of SEBS and polypropylene.

SBR thermoplastic elastomer

A thermoplastic elastomer composition is disclosed, comprising a halobutyl rubber cured by dynamic vulcanization with a multifunctional amine curing agent. The cure is effected in the presence of at least 20 parts of a mixture formed from 10 to 60 parts of a polyolefin and 1 to 90 parts of a thermoplastic elastomer. The parts based on 100 parts by weight of said rubber.

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West Chester, PA, United States of America

Ghawamedin Bayan