Abstract: This application relates to compositions of cross-linking peroxides which have excellent storage stability, without exudation of peroxide taking place, which contain the organic peroxide in a high concentration, and which are easily blendable with a rubber to be cross-linked. The compositions are obtained by mixing a softening agent with a Brookfield viscosity of 10,000 poises or less at 60 ° C. with an organic peroxide, preferably in the presence of a filler, and optionally with further ingredients.

Abstract: The invention relates to a process for (co)polymerizing vinyl monomers in the presence of a radical polymerization initiator, characterized in that said radical polymerization initiator is a 3-methylpentyl-3-peroxy alkanoate of formula (I) wherein R.sub.1, R.sub.2 and R.sub.3 represent alkyl groups each having at most 9 carbon atoms with the proviso that the total number of carbon atoms of R.sub.1, R.sub.2 and R.sub.3 is at most 11, said 3-methylpentyl-3-peroxy alkanoate being employed in an amount of 0.002 to 2.0 parts by weight, based on 100 parts by weight of monomers present, said process being carried out at a temperature above 20.degree. C. The use of 3-methylpentyl-3-peroxy alkanoates in the present invention surprisingly and unexpectedly results in a higher polymerization velocity, a shortened polymerization time, and an increase in conversion as compared with the results obtained by using other radical polymerization initiators.

Abstract: A process for the copolymerization of styrene or .alpha.-methylstyrene with an unsaturated acid derivative is disclosed. The process is carried out in the presence of a tetrafunctional organic peroxide and produces copolymeric products having significantly improved properties.

Abstract: A peroxide curing agent composition containing 20-90% of an unsaturated alkyd diluent which is fluid at room temperature, is disclosed. The curing agent is useful for the curing of unsaturated polyesters and eliminates the problem of the bleeding of harmful phthalate diluents from such cured polyesters, while providing excellent stability of the diluted peroxide.