GB1330896A - Polymerisation process - Google Patents

Abstract

1330896 Polymerization with novel initiator/ coinitiator combinations MONSANTO CHEMICALS Ltd 6 Oct 1971 [6 Nov 1970] 52862/70 Headings C3G and C3P An initiating system for the polymerization of olefinically unsaturated monomers comprises a main initiator and, as a co-initiator which encourages the polymerization of substantially all the monomer, a compound of the formula wherein R is a C 1-4 alkyl group and R<SP>1</SP> is methyl, ethyl, n-propyl or n-butyl. The preferred compound is 3,5-dimethyl-3,5-ditertiary butyl peroxy-1,2-dioxolane (i.e. all R's are -CH 3 ). The main initiator is preferably of the free radical type, such as a dialkyl or diacyl peroxide or cumene hydroperoxide, or an alkyl peresto or an azo diisobutyronitrile or similar compound. Any monomer or monomer mixture may be used, and the polymerization may be by any known method. Bulk polymerization is preferred, at 85-220‹ C., especially where a prepolymer is formed in one vessel, and then subsequently transferred to further vessels until polymerization is complete. In the example, styrene is bulk polymerized using ditertiary butyl peroxide and the above preferred compound. Other monomers specified are α-methyl styrene, vinyl toluene, methyl methacrylate and acrylate, vinyl acetate, vinyl chloride, acrylonitrile and methacrylonitrile, styrene/ acrylonitrile, styrene/butadiene, styrene/divinyl benzene. A graft polymer, e.g. of styrene and acrylonitrile or polybutadiene may also be produced.