| 摘要 |
A water-insoluble vinyl polymer is formed by polymerizing at least one water-insoluble vinyl monomer in aqueous suspension containing undissolved phosphate, the phosphate (e.g. of calcium) being one requiring more than 100 parts by weight of water to dissolve one part thereof, and adding to the suspension a water-soluble hydroperoxide (e.g. 3-50 p.p.m. by weight) and a water-soluble metal formaldehyde sulphoxylate (e.g. 5-120 p.p.m.). The monomer may be styrene and it may be polymerized in an aqueous suspension containing tri-sodium phosphate, disodium hydrogen phosphate and calcium chloride (which react to form a calcium phosphate in situ), white oil, butyl stearate, stearic acid, butylated hydroxy toluene, benzoyl peroxide, t-butyl perbenzoate, t-butyl hydroperoxide, sodium formaldehyde sulphoxylate and an alkyl aryl sulphonate. The polymer may be obtained in bead form.
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