| 摘要 |
PURPOSE:To prevent large damage to the surface layer of fine particles, by putting a mixture constituted of polymer resin and inorganic hard spheres whose diameters are larger than the average particle sizes of the polymer resin particles in an air- permeable bag composed of a material which does not allow the fine particles to pass through and drying them in a rotating type dryer while the agglomeration of the fine particles is being suppressed. CONSTITUTION:Inorganic hard particles such as alumina, silica and so on which have larger diameters then the average particle sizes of the polymer resin particles and a large specific gravity are used as the inorganic hard particles mixed with a wet polymer. A bag in which the mixture is placed is prepared with a material which has an air-permeability to be necessary for drying the polymer resin particles in a rotating drying process while the falling out of the polymer resin particles is being completely suppressed and at the same time does not permit the passage of the fine particles. As the rotating dryer, any conventional type can be used. The wet polymer resin fine particles are dried by hot air in the rotating type dryer and the secondary agglomeration of the resin fine particles are suppressed by the impact action of the inorganic hard particles having large specific gravity generated by rotation of the rotating type dryer. No damage is thereby produced to the surface of the dried polymer resin fine particles, which exist as the primary particles. |
