| 摘要 |
PROBLEM TO BE SOLVED: To heighten fluidity and enable uniform scattering by attaching a specific amount of fine powder having a specified particle diameter or less as a lubricant on the surface of glass beads for spherical retroreflectors having specific particle diameters and refractive indexes. SOLUTION: This glass beads for reflectors have 20-100μm particle diameters and 1.9-2.2 refractive index. Fine powder having <=5μm particle diameter and in the proportion of 0.01-1 wt.% is attached thereto as a lubricant. The glass beads 5 for reflectors have a composition of 50 wt.% TiO2, 30 wt.% BaO, 10 wt.% ZrO2, 4 wt.% CaO, 5 wt.% ZnO and 1 wt.% SiO2, and further having 2.18 reflective index and 20-100μm particle diameters. The fine powder 6 having <=3μm particle diameter and comprising ZnO having 0.5 average particle diameter in a proportion of about 0.1 wt.% is attached on the grass beads 2. The production method of the glass beads comprises heating a glass powder by an oxygen gas burner to globe the powder. At the time, ZnO is sublimed and solidified on the surface to be attached thereon.
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