Suspensions of thermally labile organic compounds comprising polyvinyl alcohol and surfactant for use in polymerization processes

摘要

The aqueous suspensions comprise 35 to 60% by weight of one or more solid thermally labile organic compounds, at least one polyvinyl alcohol with an average degree of hydrolysis from 60 to 80% and at least one non-ionic surfactant with an average HLB value from 14.5 to 20.0. The organic compound is selected from diacyl peroxides, peracids and peroxydicarbonates, and the particle size distribution in the final suspension has a d90 of less than 20 micrometres. The final suspension may additionally comprise thickeners, pH-adjusting agents, sequestering agents and biocides. The process to prepare this suspension involves a mixing step, followed by the milling of the mixture to form a coarse suspension, and then further milling or homogenization to more finely divide the compound. Preferred suspensions relate to bis(4-tert-butylcyclohexyl) peroxydicarbonate, dimyristyl peroxydicarbonate and lauric acid. The suspensions are suitable for use in polymerization processes.