Addivant was a leading global supplier of a comprehensive portfolio of additives including antioxidants, antiozonants, inhibitors, polymer modifiers and UV stabilizers used by customers to improve the production and performance properties of polymers, plastics and rubbers.  Addivant was headquartered in Connecticut and maintained a global footprint with 11 plants on five continents.

SK Capital acquired the Antioxidant and UV Stabilizer Solutions business of Chemtura Corporation in May 2013. The business was renamed Addivant upon becoming an independent company.

SK Capital acquired SI Group in October 2018 and merged it with Addivant. The newly combined company is marketed under the SI Group brand.