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SI Group's facility in Morgantown, WV, is the world's largest phosphite antioxidant production facility. SI Group continuously focuses on the WESTON™ antioxidant portfolio by investing in better technology, manufacturing processes, and production capacity. This continual investment allows for better traceability and sustainable manufacturing processes ensuring batch-to-batch consistency and a reliable, steady supply of phosphite antioxidants.

Why Choose WESTON™ Liquid Phosphite Antioxidants?
  • Strong track record of safety
  • Fully committed to Responsible Care®
  • Committed to global regulatory compliance (REACH)
  • High-purity phosphite antioxidants
  • Effective against thermal and discoloration degradation
  • Synergy capabilities when used with hindered phenols
  • Broad FDA food contact application approval
  • Robust technical support
  • Immediate PQI assistance
  • R&D labs in Morgantown, WV, and globally
  • On-site technical expertise for a new project

Featured Grade 

Ongoing innovation allows customized solutions and a strong pipeline of groundbreaking, patented, next-generation phosphite technology for food packaging. WESTON™ 705 is the future of nonylphenol-free liquid phosphite antioxidant that offers 20% higher phosphorous content. Furthermore, WESTON™ 705 is compatible with various elastomer and plastic packaging systems. 

Why WESTON™ Liquid Phosphite Antioxidants for Packaging Plastics

Packaging plastics require stabilization additives that help improve color and processing efficiency. Moreover, food contact packaging plastics require FDA approval for stabilizing polymer additives formulations. The WESTON™ portfolio provides packaging plastic manufacturers with a liquid antioxidant solution to improve color and comes with a broad base of food contact approvals. High-purity phosphite antioxidants protect against heat degradation and discoloration while providing additional synergies when used with hindered phenol additives.  


The WESTON™ liquid phosphite stabilizer portfolio has a range of drop-in solutions depending on your resin and packaging applications. With many grades handling and feeding just like TNPP, they are even easier to test without costly formulation changes. If you are unsure which grade works best for your formulation, click the button below to talk to one of our experts today!

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