| 摘要 |
<p>1,245,166. Polymerizing acrylic nitrites in emulsion. DOW CHEMICAL CO. 31 Jan., 1969 [5 Feb., 1968]. No. 5400/69. Heading C3P. A monomeric mixture A comprising 20-90 weight per cent of an acrylic nitrile, 0-70 weight per cent of one or more monoalkenyl aromatic, open chain aliphatic conjugated diene, or alkyl acrylate monomers, and 0-30 weight per cent of anα,#-ethylenically unsaturated carboxylic acid is emulsified in an aqueous medium, polymerization is initiated and maintained to at least 30% conversion, then continuing under polymerization conditions a monomeric mixture B comprising 0-100 wt. per cent of one or more monoalkenyl aromatic, open chain conjugated diene, or alkyl acrylate monomers, 0-25 wt. per cent of a different neutral ethylenically unsaturated monomer, and 0-30 wt. per cent of anα,#-ethylenically unsaturated carboxylic acid is added, each separately or as a mixture, continuously or incrementally, the weight ratio of A:B being between 5:95 and 25:75, and polymerization is carried substantially to completion. Exemplified monomers are butadiene, styrene, acrylic acid, butyl acrylate, methyl methacrylate, hydroxyethyl acrylate, acrylonitrile, and itaconic acid. In the second stage, a chain transfer agent such as carbon tetrachloride can be added with the monomer(s).</p> |
