| 摘要 |
1477160 Glass composition PENNWALT CORP 26 Nov 1974 [10 Dec 1973] 51139/74 Heading ClM [Also in Division C3] A glass, which has been finely divided, has an SiO 2 content of 25--50 wt. per cent and contains a fluxing agent to reduce its fusion temperature to below 1350‹ C., and has had incorporated therein, at the time of fusing, from 5-60 wt. per cent, based on the weight of the glass, of an (X-Ray opaque) oxide or carbonate of La, Hf, Sr, or Ta. Preferred fluxing agents are Na 3 AlF 6 , CaF 2 , SrF 2 and TaF 5 . Apart from SiO 2 , the glass may also contain Al 2 O 3 and/or H 3 BO 3 in an amount of 5-30 wt. per cent. The glass is used as a filler in an acrylic polyester dental filling composition. |
