| 摘要 |
PURPOSE:To enable introduction of a necessary component which causes easily devitrification and to improve the desirable characteristics by controlling the temp. of a nozzle part for melt spinning melted glass, and suppressing devitrification of the glass. CONSTITUTION:In the longitudinal direction of a nozzle 13, >=1 forced cooling device 16 which surround the nozzle 13 for spinning the melted glass 12 and can cool the zone limited to <=1/2 of the total length of the nozzle 13 are arranged and a heating device 15 is also provided. When the glass 12 passes through the nozzle 13 having the 10-100 fold length of the inside diameter of the main part of the nozzle 13, the nozzle 13 is cooled at the temp. lowering rate of 10-30 deg.C/ min at the zone within the devitrification temp., and the temp. lowering rate of the glass 12 is reduced at the zone other than the devitrification temp. zone. By this method, e.g. ZrO2, TiO2 or the like which causes easily the devitrification can be introduced, and the desirable characteristics, such as water resistance are improved. |
