GB861817A - Improvements in or relating to the polymerization of diallyl phthalate - Google Patents

Abstract

A solid diallyl phthalate prepolymer is prepared from diallyl phthalate by polymerizing at an elevated temperature, e.g. above 70 DEG C., a mixture containing diallyl phthalate monomer, water, an organic peroxide or organic hydroperoxide catalyst, and a polymerization modifier of the formula <FORM:0861817/IV (a)/1> where X is chlorine or a hydroxyl radical or any group which can be converted to a hydroxyl group under reaction conditions, R is a methyl and/or ethyl and/or propyl radical, m is 0 to 4, the total number of carbon atoms in the R substituents is less than 5, and n is 0 to (4 - m), the modifier comprising 1 to 50% by weight based on the monomer, the reaction being discontinued before substantial gelation occurs by lowering the temperature below the polymerization temperature, unreacted monomer being separated from the prepolymer formed, and solid prepolymer recovered. Optional dispersing-agents, e.g. animal glue, clay and sodium tripolyphosphate, may be employed for the reaction. When dimethyl benzyl chloride or dimethyl benzyl alcohol is used as polymerization modifier, optimum ratios by weight thereof to monomer are 1 : 3.5 and 1.4. Other modifiers specified are benzyl alcohol and methyl-, isopropyl-, o-chlor-, and p-chlor-benzyl alcohols. It is stated that the modifier apparently functions to control the chain length of the polymer; excess cross-linking does not occur and a prepolymer is obtained without gelation. The proportion of water may be from 2 to 600% by weight of monomer. Catalysts in a proportion of 0.1 to 10% by weight of monomer are exemplified by benzoyl, acetyl benzoyl and succinyl peroxides and t-butyl perbenzoate. Of the isomeric diallyl phthalates that may be employed, orthophthalates are preferred. The prepolymers can be moulded to acetone-soluble thermoplastic or thermoset products at moderate temperatures and pressures. Chopped fibres, magnesium oxide and wood flour may be incorporated in the cured prepolymer.