| 摘要 |
<p>1425607 Elastomeric compositions M KUHN - TEMMLER and D KUHN [trading as TEMMLER & CO INHABER KUHNTEMMLER & CO] 16 May 1973 [17 May 1972] 23378/73 Headings C3T C3S and C3R A room temperature hardening elastomeric impression composition suitable for dentistry purposes comprises an #, #<SP>1</SP>-dihydroxy-polydimethylsiloxane and a hardener which comprises an organo-tin compound, as accelerator, and a crosslinking agent which comprises an organic silicate having in the molecule at least one alkoxy-terminated polyoxypropylene group, wherein the alkoxy group contains 1-4 carbon atoms, and methoxy and/or ethoxy groups. Suitable accelerators are dibutyltin dilaurate and/or dibutyltin dioctoate. Suitable crosslinking agents may be represented by the formulae where R 1 -R 5 may each be a methyl or ethyl group and R 3 -R 6 may each be a group of the formula The crosslinking agent may be prepared by partial re-esterification of hexamethoxydisiloxane, or tetramethyl- or tetraethylsilicate with a polyoxypropylene glycol monoalkyl ether in the presence of an alkaline catalyst. In the examples compositions are prepared from #, #<SP>1</SP>- dihydroxydimethylpolysiloxane; dibutyldilaurate; a crosslinker prepared by reacting polyoxypropylene glycol monobutyl ether and a suspension of potassium silicate in methanol prepared from tetramethylsilicate and KOH; and either quartz flour or gypsum, and optionally tetramethylsilicate and polymethylsilicate, and are hardened at room temperature.</p> |
