Tert-Butyl peroxy-3,5,5-trimethylhexanoate

Tert-Butyl peroxy-3,5,5-trimethylhexanoate (CAS 13122-18-4) is an organic peroxide initiator commercially available under trade names including Trigonox 42S, Luperox 270, and the shorthand designation 42S. It carries no assigned E-code and is registered under REACH with EC number 236-050-7.

In polymer manufacturing, this peroxide initiates free-radical polymerization of styrene, acrylates, and vinyl monomers at elevated temperatures, typically in the 100–130°C range. It is also used to cross-link rubber compounds and unsaturated polyester resins in coatings and sealant formulations, where controlled decomposition rate determines final network density.

This material is supplied under REACH compliance and is subject to EU transport regulations governing organic peroxides. It is available in stabilised liquid form, typically in drums or IBCs suited to industrial volumes. Buyers should confirm concentration grade and phlegmatiser content with the supplier prior to ordering.