| 摘要 |
<p>1,188,252. Suspension polymerization. ATLANTIC RICHFIELD CO., and KOPPERS CO. 27 May, 1968 [26 May, 1967], No. 25350/68. Heading C3P. Polymer beads are produced by heating a suspension of an aromatic compound, substituted by at least one vinyl orα-substituted vinyl group, containing an oil-soluble free radical initiator in an aq. medium with the aid of a finely divided phosphate suspending agent, which requires more than 100 parts by wt. of water to dissolve one part by wt. thereof, and at least 0À0003% by wt. based on the monomer, of a water soluble sulphite, or a compound which under the polymerization conditions will form such a sulphite, is added to the suspension before the monomer has polymerized to the bead identity point. The monomer may be styrene with optionally 2-ethyl-hexyl acrylate. The initiator may be a mixture of benzoyl peroxide and t-butyl perbenzoate or azobisisobutyronitrile. The phosphate may be tricalcium phosphate. The sulphite or precursor thereof may be sodium bisulphite, sodium or potassium metabisulphite, sodium hydrosulphite or -sulphide, sodium formaldehyde sulphoxylate or sulphurous acid.</p> |
