| 摘要 |
In a process of polymerizing monomers of formula CH2=CXR where X is hydrogen, alkyl or halogen and R is an organic radical to obtain a syrupy solution of polymer in the monomer, the polymerization is carried out in the presence of such a quantity of initiator and at such a temperature that the initiator is completely destroyed and the reaction automatically stopped once the desired conversion is reached, this conversion being lower than 70%. The process may be carried out continuously by continuously feeding monomer and discharging syrup. Specified monomers are acrylic and methacrylic esters, styrene, vinyl acetate and dimethyl itaconate. The initiator may be an organic peroxide or hydroperoxide or an azo compound, e.g. benzoyl peroxide, lauroyl peroxide, di-t.-butyl peroxide, t.-butyl peracetate and azo-bis-isobutyronitrile, and chain transfer agents, e.g. n-butyl, octyl, 2-ethylhexyl and dodecyl mercaptans, may also be present. Examples describe the preparation of syrups by polymerizing methyl methacrylate in the presence of (1) lauroyl peroxide, (2) lauroyl peroxide and n-butyl mercaptan and (4) t.-butyl peroxide and n-octyl mercaptan; and by copolymerizing methyl methacrylate with (3) styrene in the presence of lauroyl peroxide and (4) ethylene glycol dimethacrylate in the presence of benzoyl peroxide. Apparatus suitable for carrying out the process is described and illustrated. |
