PURPOSE: To enhance the loading resistance of hollow glass microspheres by making the microspheres have a specified diameter, and thickness, and internal gas pressure and contain blow gas substance of neither a latent solid nor latent liquid and allowing the wall to have none of hole, thick well part or section, a sealed chip and a bubble.
CONSTITUTION: A glass composition is heated and fused into flowable molten glass, which has a specified viscosity and surface tension. This composition is passed through the annular space 8 of a blow nozzle 5 and crosses orifices 6a and 7a to form a thin liquid molten glass film. Inert blow gas of heated N2, etc., is supplied to the internal surface of the molten glass film to form a thin and long cylinder which expands downward and also has the outside closed and internal end connected to the external edge of the orifice 7a. When the cylinder is fallen freely from the blow nozzle 5 by a lateral injection means with inert fluid consisting of heated N2, the thin and long cylinder becomes spherical soon. Water is jetted thereto for quenching, solidification, and hardening and then the hollow glass microsphere is obtained which has 200 to 10,000 μm diameter, 0.1 to 100 μm wall thickness, and ≤0.21 kg/cm2 internal gas pressure and contains neither latent solid or latent liquid blow gas substance.
| JPS6197145A | 1986-05-15 |
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