process for preparation of polyvinyl chloride by suspension with a porous structure and a high apparent density

摘要

1308574 Porous polyvinyl chloride KNAPSACK AG 19 April 1971 [24 March 1970] 24682/71 Headings C3C and C3P Porous polyvinyl chloride is prepared by polymerization of vinyl chloride in aqueous suspension in the presence of a protective colloid and an initiator, the suspension being agitated throughout save for a pause of between ¢ and 1¢ hours commencing between 10 and 20 minutes after the start of the reaction, the polymer resulting being isolated and dried. The reaction is performed at temperatures between 50‹ and 65‹ C., preferably 55‹ C. The initiator is soluble in the monomer. Examples given are tertiary butylperpivalate, diisopropylperoxidicarbonate, and acetyl cyclohexane-sulphonyl peroxide. The initiator is used in a quantity of preferably 0À02% by weight of vinyl chloride. The resulting polyvinylchloride has, at best, a K value of 70, a bulk density of 470 g./litre and a softener absorption power of at least 28%.