Ethyl methyl ketone peroxide

Ethyl methyl ketone peroxide (MEKP, CAS 1338-23-4) is an organic peroxide supplied under trade names including Ketonox, Permek N, and Butanox. It is a reactive oxidizing agent classified under EC 215-661-2 and handled under strict ADR transport regulations due to its peroxide content.

In unsaturated polyester resin systems, MEKP acts as a free-radical initiator, decomposing in the presence of a cobalt accelerator to generate radicals that trigger cross-linking and cure the resin at ambient temperature. It is also used to initiate polymerization in gel coats and fiberglass-reinforced composites within the plastics and rubber processing industries.

MEKP is available in stabilized liquid formulations at varying active oxygen concentrations, typically diluted in plasticizers to reduce hazard classification. Supply is subject to REACH registration requirements, and handling must comply with EU Regulation 528/2012 where applicable. Packaging is typically in UN-approved containers suited for organic peroxide transport categories.