| 摘要 |
PROBLEM TO BE SOLVED: To obtain the dispersion without the settling being gelled or the silica particles precipitated when let stand for a long time by passing a slurry consisting of silica and polar solvent through a throttle mechanism with a differential pressure between its inlet and outlet specified to crush the slurry. SOLUTION: A passage 4 consisting of the thin tube having an optional length and a diameter smaller than the inner diameter of a tube 1 is provided in the tube 1, and a throttle mechanism with ratio of the diameter of the tube 1 to that of the diameter-decreased part controlled to 5, preferably 10, with the diameter of the diameter-decreased part controlled to 50μm to 5 mm, preferably 70μm to 1.5 mm, and with the differential pressure between the inlet and outlet controlled to 400-3,500 kgf/cm<2> is furnished. A slurry contg. <=50 wt.%, preferably <=30 wt.% or more preferably <=20 wt.%, water and a polar solvent such as methanol and kept at >=pH8, preferably >=pH9, is passed through the throttle mechanism and crushed.
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