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Process for the preparation of monodispersed polymer beads

  • US 5,292,814 A
  • Filed: 03/14/1991
  • Issued: 03/08/1994
  • Est. Priority Date: 04/29/1987
  • Status: Expired due to Term
First Claim
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1. A process for the preparation of monodispersed polymer beads having a diameter of 0.5 to 50 μ

  • m, wherein, in a first homogeneous stage, a seed polymer is prepared by polymerizing a monomer dissolved in at least one organic solvent, yielding a monodispersed seed, in the presence of a polymerization initiator and triphenylmethane or a compound having the formula R--X, whereinR is a saturated or unsaturated, linear or branched aliphatic radical with more than 6 carbon atoms, andX is selected from the group consisting of a hydrogen, halogen atom, a hydroxy group, a C1 -C6 alkoxy group, an amino group, a C1 -C6 alkylamino group, a di-C1 -C6 alkylamino group, a phenyl group or a phenyl group optionally substituted with a C1 -C4 alkyl group, a polyoxyethylenated hydroxy group or a sulfonic acid group;

    separating the seed polymer obtained; and

    wherein, in a second stage, an emulsion polymerization is carried out by polymerizing a monomer in the presence of the seed polymer, an emulsifier, a polymerization initiator and optionally a cross-linking agent, in an aqueous medium.

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