2.
    发明专利
    未知

    公开(公告)号:FR1466640A

    公开(公告)日:1967-01-20

    申请号:FR44468

    申请日:1965-12-31

    Applicant: BASF AG

    Abstract: A process for the continuous emulsion polymerization of conventional olefinically unsaturated monomers which are practically insoluble or at most partly soluble in water, in aqueous medium in the presence of conventional polymerization catalysts, comprises continuous supplying monomers exclusively in the form of a preformed aqueous emulsion through a tube in an upward flow at a flow velocity of 5 to 100 cm. per sec. to the lower part of a vertically arranged circulation system, blending with an excess of polymer dispersion which has already formed, and polymerizing in the circulation system without the use of mechanical stirrers to a mean conversion of more than 75%, the polymer dispersion being withdrawn at a point not higher than the point of entry of the monomer emulsion into the circulation system and at the same rate as the monomer emulsion is supplied. Optional process features include preblending of monomer with polymer, a temperature difference between ascending and descending parts, bubbling inert gas through the ascending part, boiling the ascending dispersion with the aid of reduced pressure, and complex circulation systems. In examples, monomers polymerized are: (1) butyl acrylate-acrylic acid, (2) and (3) methyl methacrylate in the presence of dispersed polymethyl methacrylate, (4) and (5) butyl acrylate-vinyl acetate-acrylic acid, (6) and (7) vinyl propionate-sodium vinyl sulphonate, (8) styrene-acrylic acid-acrylonitrile, (9) vinylidene chloride-acrylonitrile-methacrylamide and (10) butyl acrylate-vinyl acetate-sodium vinyl sulphonate-acrylic acid; the catalyst being potassium persulphate or azodiisobutyronitrile and the emulsifier being selected from dodecylbenzene sulphonate, C10-C16-alkyl sulphonate, polyethoxylated octadecyl alcohol, turkey red oil and sodium salt of sulphochlorinated paraffins. The process can also be applied using other monomers such as ethyl acrylate, vinyl pivalate, vinyl chloride, methacrylic acid, acrylamide and N-methylolmethacrylamide; and with other catalysts, e.g. hydrogen peroxide, ammonium persulphate, benzoyl peroxide and dialkyl percarbonates.

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