A process for the preparation of coated polymer particles containing superparamagnetic crystals, said process comprising reacting porous, surface-functionalized, superparamagnetic crystal-containing polymer particles of diameter 0.5 to 1.8 μm with at least one polyisocyanate and at least one diol or at least one epoxide.
1. A process for the preparation of coated polymer particles containing superparamagnetic crystals, said process comprising reacting porous, surface-functionalized, superparamagnetic crystal-containing polymer particles of diameter 0.5 to 1.8 μm with at least one epoxide compound.
2. A process as claimed in claim 1 wherein one epoxide is used, said epoxide being glycidyl methacrylate, said reaction being effected in the presence of iron (III) chloride.
3. A process as claimed in claim 1 wherein at least two epoxides are used.
4. A process as claimed in claim 3 wherein said at least two epoxide compounds comprise at least one bisepoxide compound.
5. A process as claimed in claim 4 wherein said epoxide compounds comprise glycidol and 1,4-bis-(2,3-epoxypropoxy)butane.
6. A process as claimed in claim 4 wherein said epoxide compounds comprise 1,4-bis-(2,3-epoxypropoxy)butane and 2,2-bis(4-(2,3-epoxypropoxy)phenyl )-propane.
7. A process as claimed in claim 3 wherein said epoxide compounds comprise glycidol, allylglycidyl ether and 1,4-bis-(2,3-epoxypropoxy)butane.
8. A process as claimed in claim 3 wherein one of said epoxide compounds is a polyethylene glycol diglycidylether with a molecular weight of 150 to 1000 g/mol.
9. A process as claimed in claim 1 wherein the diameter of the polymer particles is between 0.5 to 1.2 μm.
10. A process as claimed in claim 2 wherein the diameter of the polymer particles is about 1 μm.