| 摘要 |
PROBLEM TO BE SOLVED: To obtain a praseodymium oxide-contg. ultraviolet absorber which absorbs ultraviolet rays in the whole wavelength region by incorporating a pulverized praseodymium yellow pigment into an ultraviolet absorber. SOLUTION: This absorber contains a pulverized praseodymium yellow pigment. The pigment before pulverizing is used for coloring chinaware, is commercially available, and can be produced e.g. by mixing kaolin or zircon with praseodymium oxide (Pr6 O11 ) in a wt. ratio of usually (99:1)-(50:50), esp. pref. (95:15)-(85:15), and baking the resulting mixture at about 1,300 deg.C. The pulverized pigment used here can be obtd. by pulverizing the pigment obtd. as above. The pulverizing is done to such an extent that the pigment no longer looks yellow, e.g. to an average particle size of 0.1μm or lower.
|
