| 摘要 |
PURPOSE:To manufacture hollow and cellular vitreous granules which are light in weight and have low heat conductivity by coating a substance for piercing holes with a mixture of glass powder with an expanding agent, piercing holes by primary heating, and expanding the glass by secondary heating. CONSTITUTION:A powdered mixture consisting of glass powder such as powder of ordinary soda lime glass and an expanding agent such as calcium carbonate is added to a substance for piercing holes such as foamed polystyrene beads in a stirrer with stirring, and the substance is coated with the mixture with a binder such as sodium silicate or PVA in-between to prepare a mixture as a starting material. This mixture is charged into a heating furnace, where it is primarily heated to a temp. at which the substance for piercing holes is decomposed or oxidized to the softening temp. of the glass powder to pierce holes. The glass is then expanded by secondary heating to a temp. above the softening temp. of the glass powder. Hollow and cellular vitreous granules contg. many closed cells are obtd. |
