| 摘要 |
1430285 Pt-catalysed silicone rubber compositions for dental impressions WACKERCHEMIE GmbH 11 Oct 1973 [11 Oct 1972] 47616/73 Heading C3T [Also in Division A5] Dental impressions are taken with a composition containing (a) a vinyl-terminated polydiorganopolysiloxane, (b) an organopolysiloxane having at least three Si-bonded hydrogen atoms per molecule, (c) a catalyst for the addition of SiH to vinyl groups at room temperature, and (d) customary additives, e.g. fillers and plasticizers. The composition is conveniently made up from a two-part pack in which components (b) and (c) are kept separate, other components being mixed with either. In the example 10 p.b.w. of a mixture of vinyl-terminated polydimethylsiloxane of 1400 cP./23‹ C., quartz powder and CaCO 3 powder in 6 : 2 : 1 weight ratio, with 0À3 wt. per cent of a complex of H 2 PtCl 6 with divinyl tetramethyl disiloxane, is mixed with 1 p.b.w. of a trimethylsilyl-terminated copolymer of (CH 3 ) 2 SiO and (CH 3 )HSiO units in 12 : 1 ratio, immediately before use. |
