Morphology control of clay-mineral particles as supportsfor metallocene catalysts in propylene polymerization

Spray-dry granulation of clay minerals was studied to obtain clay mineral base support material for metallocene supported olefn polymerization catalysts. The morphology of the granules was strongly influenced by the nature ofthe clay mineral itself. Because of swelling characteristics of montmorillonite, its water dispersion was highly viscouseven in the low slurry concentration (< 4 wt %). Therefore, it was very diffcult to control the granule characteristicssuch as size, shape, and inside structure by the spray drying of the clay mineral slurry. Then we examined somemethods in order to change the clay mineral surface properties for getting less viscous dispersion. It was found thatthe milling of montmorillonite increased the amount of surface OH groups. This surface characteristic change shouldpromote the interaction between the edges and basal planes of the primary particles of milled montmorillonite, resultingin the lowering the slurry viscosity. The milling is effective for overcoming diffculty in use of high concentrationmontmorillonite slurry in spray-dry granulation which is indispensable for producing granules in the wide range of size(10–50 μm). The spray-dried montmorillonite granules are useful as a support-activator for an olefn polymerizationcatalyst combined with metallocenes. Polyolefns J (2016) 3: 79-92

Keywords:

metallocene catalyst , activator , clay minerals , support , spray-dry