BIMSM Pharma Stoppers

Specialty elastomer for pharmaceuticals  

Exxpro™ specialty elastomers are brominated isobutylene paramethyl-styrene terpolymers (BIMSM). Together with Exxon™ halobutyl rubber, Exxpro specialty elastomers help the healthcare industry meet ever-changing requirements related to cleanliness, drug compatibility, low extractables and leachables.

Ideal for sensitive drugs and other demanding applications, Exxpro specialty elastomers are a super-clean solution and cost-effective alternative to expensive coated stoppers. In the tire industry, Exxpro is used for high-performance bladders and envelopes.


  • High temperature resistance
  • Greater heat stability compared to EPDM rubbers
  • Low permeability and high damping similar to butyl rubber
  • Wide latitude in cure and cocure with a variety of rubbers
  • Ozone/weathering resistance
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Elastomers solutions for pharmaceutical packaging and medical devices at IOM3 webinar 2020

Join our webinar with specialist elastomers and butyl application development technologist Dr. Anas Mujtaba to learn more about how Exxon™ butyl rubber, Exxpro™ specialty elastomer and Santoprene™ TPV apply for pharmaceutical packaging and medical devices.

Download the presentation or watch the replay

Featured resources

View highlighted news, events, technical papers and case studies below. To see our full collection of resources, browse our Library.
  • ExxonMobil Chemical Library icon

    ExxonMobil™ PP for healthcare and medical applications

    ExxonMobil PP is a versatile material that can offer cost-effective performance flexibility for healthcare and medical applications. It is suitable for all sterilization techniques and selected grades comply with regulatory requirements for medical use.

    Read more
  • ExxonMobil Chemical Library icon

    Exxpro™ Specialty Elastomer Grade 3433

    Model formula for pharmaceutical closure Exxpro Specialty Elastomer Grade 3433.

    Read more
  • ExxonMobil Chemical Library icon

    Sustained commitment: Supply, innovation, technology and quality

    An interview with Kurt Aerts, Vice President, Global Specialty Elastomers and Butyl, ExxonMobil.

    Read more
  • ExxonMobil Chemical share button icon

    Pioneers of innovation: The fathers of synthetic rubber

    Read how these pioneers have opened doors to further learning and exploration in their fields and beyond.

    Read more
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