Brasnox D
Brasnox D, Methyl ethyl ketone peroxide in dimethylphthalate, CAS 1338-23-4, Organic peroxide, Brasnox® D is a polymerization initiator in unsaturated polyester resins at room temperature.
https://www.nouryon.com/product/brasnox-d-methyl-ethyl-ketone-peroxide-in-dimethylphthalate-cas-1338-23-4/