GB875796A - Emulsion polymerisation apparatus - Google Patents

Abstract

<PICT:0875796/IV (a)/1> A mixing apparatus for polymerizing emulsions of polymer components is provided with a vertically mounted rotating member, preferably a cone, cylinder or a series of discs mounted on a shaft, the co-acting liquid components being discharged close to the surface of the rotating member, at the top and bottom respectively. The monomer fed into the bottom, is formed into fine particles by the rotating member and rises in counter-current with the emulsion forming and polymerizing components flowing downwards. A suitable apparatus consists of a jacketted vessel 1, having a central shaft 5 on which a series of spaced discs are mounted. An inlet for the monomer at 6 discharges adjacent the lowest disc, and an inlet 7 for the second component is similarly disposed against the top disc. The polymer is discharged at 8. A reflux condenser is mounted at 9. The apparatus may be operated at normal, lower or higher pressures. The dimensions and stirring speed are co-related, e.g. with a cylindrical stirrer 4in. diameter and vessel 6in. diameter stirring speed should be 440-880 r.p.m. In examples, monomers polymerized include styrene, vinyl acetate, vinyl and vinylidene p chloride, acrylonitrile, esters of acrylic acid or methacrylic acid, olefines, and co-polymer mixtures, e.g. styrene-butadiene, methyl methacrylate-butatiene. In operation, vessel 1 is charged with an aqueous mixture containing ammonium polymethacrylate and the sodium salt of sulphonated methyl oleate, heated to 80 DEG C. and stirred at 600 r.p.m. An aqueous mixture of sulphonated methyl oleate and hydrogen peroxide passes through the top inlet 7, and methyl methacrylate monomer through the bottom inlet 6. After 1 hour a further addition of hydrogen peroxide is admitted through inlet 7. After a further few hours a creamy emulsion containing 48% of solids flows through discharge 8.ALSO:A mixing apparatus for polymerizing emulsions of polymer components is provided with a vertically mounted rotating member, preferably a cylinder, cone or series of discs mounted on a shaft, the co-acting liquid components being discharged close to the surface of the rotating member, one at the top thereof, and the other at the bottom. The monomer fed into the bottom, is formed into fine particles by the rotating member, and rises in counter-current with emulsion forming and polymerizing component flowing downwards. At the steady state "Taylor" rings of liquid are formed in vertical series, as segmented layers promoting mass transfer of liquid between <PICT:0875796/III/1> the segments. A suitable apparatus consists of a jacketted vessel 1, having a central axis 5 on which a series of spaced discs 2 are mounted. An inlet for the monomer at 6 discharges adjacent the lowest disc, and an inlet 7 for the second component is similarly disposed against the top disc. The polymer is discharged at 8. A reflux condenser is mounted at 9. The apparatus may be operated at normal, or sub- or superatmospheric pressures. In a modification the central rotating member is a cylinder, as illustrated in the Figure accompanying the Provisional Specification. The dimensions and stirring speed are correlated, e.g. with a cylindrical stirrer 4 inches diam. and a vessel 6 inches diam. stirring speed should be 440 to 880 r.p.m. In examples monomers polymerized include styrene, vinyl and vinylidene chloride, acrylonitrile, esters of acrylic or methacrylic acid, olefines and co-polymer mixtures, e.g. styrene-butadiene, methyl methacrylate-butadiene.