| 摘要 |
PURPOSE: To obtain pellets having a clear spherical structure, high pressure resistance and wear resistance, by suspending a xanthin derivative in a solvent immiscible with water, adding water or a water/alcohol mixture and then cooling. CONSTITUTION: Xanthin derivative powder having 20-200μm average particle diameter is suspended in an insoluble liquid (e.g. cyclohexane, benzine or petroleum ether) immiscible with water, having 60-160 deg.C, preferably 70-130 deg.C boiling point with stirring at 40 to 70 deg.C, preferably 40-50 deg.C. Water or a water/alcohol mixture in an amount of 10-40wt.% based on the xanthin derivative is added to the suspension. The suspension is cooled at 5-50K/hour to a room temperature (optionally the stirring rate is reduced to 1/3 to 2/3 the original rate). Pellets are separated and dried to give a spherical structure having 0.3-4mm particle diameter, >=0.5 bulk density and a clear spherical structure.
|
