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Interplastic Corporation is a specialty chemical company with headquarters in St. Paul, Minnesota. The company focuses on the production and distribution of unsaturated polyester and vinyl ester resins, gel coats, colorants, and putties for the composites and cast polymer industries.

Interplastic is the leading manufacturer of unsaturated polyester, vinyl ester and specialty resins, gel coats, colorants and putties under the CoREZYN® and Silmar® brand names for the composites, cast polymer, and solid surface industries. All CoREZYN and Silmar products are sold direct and through our extensive network of distributors in North America and around the world.

Interplastic has been manufacturing CoREZYN® thermoset resins, gel coats, and colorants for the composites and cast polymer industries since 1959. The division introduced CoREZYN epoxy-based vinyl esters in 1978. Today, they produce the most extensive line of vinyl ester resins in the marketplace. CoREZYN vinyl esters have become the resin of choice, for specialized high-performance, high-corrosion applications within the marine, transportation, and construction industries.

Interplastic acquired Silmar® brand resins from an affiliate of British Petroleum in 1993. They then became one of the world’s largest casting and solid surface resin producers with facilities in California and Kentucky. When manufacturers are looking for low color (clear) resins for filled and clear castings, Silmar is the world’s premier brand. With its 45-year history of quality and reproducibility, Silmar is able to meet the toughest customer demands. Interplastic introduced its line of Silmar clear gel coats in 2004.

The high performance gel coats were developed in 2011 for use above and below the waterline in marine applications. Integrity stands for consistent quality and color from batch-to-batch giving our customers superior application and repair performance.