Patent ID: 7011963

Claim:
A process for the synthesis of a bead-shaped, cross-linked, hydrophilic copolymer, comprising: radically polymerizing a monomer phase, in a bead polymerization process, in the presence of a polymerization initiator and a protective colloid, the monomer phase comprising: monomers, and a diluent, the monomer phase being present during the polymerization in dispersed form as droplets in a dispersion medium comprising an organic solvent selected from the group consisting of aliphatic hydrocarbons with 5 to 7 carbon atoms; to thereby obtain said bead-shaped, cross-linked, hydrophilic copolymer, the copolymer having a binding activity toward ligands containing nucleophilic groups, wherein said monomer phase comprises as monomers a) 5 to 40 wt % of hydrophilic monomers which contain a vinyl group, said hydrophilic monomers being capable of radical polymerization, and being capable of forming at least 10% aqueous solutions at room temperature, b) 30 to 50 wt % of monomers which contain a vinyl group and an additional functional group, said monomers being capable of radical polymerization and being capable of forming at least one covalent bond in a reaction with at least one nucleophilic group of a ligand, and c) 20 to 60 wt % of cross-linking monomers which contain two or more ethylenically unsaturated polymerizable groups, said cross-linking monomers being capable of radical polymerization, wherein a), b) and c) add up to 100 wt %, wherein said monomer phase comprises as diluent a mixture of methanol and water in the ratio of 1:1.0 to 1:4.0, wherein a ratio of monomer phase to dispersion medium ranges from 1:2.0 to 1:4.0, and wherein a ratio of monomers to diluent ranges from 1:1.7 to 1:2.4.