| 摘要 |
1,211,699. Halogen-free platinum-siloxane complexes. GENERAL ELECTRIC CO. 14 Nov., 1967 [1 Dec., 1966 (2)], No. 51817/67. Headings C3S and C3T. A platinum-siloxane complex free of available inorganic halogen has the average general formula wherein each It is a monovalent hydrocarbon or halohydrocarbon radical free of aliphatic unsaturation, R<SP>1</SP> is an unsaturated monovalent hydrocarbon or halohydrocarbon radical, R<SP>11</SP> is a radical R<SP>1</SP> chemically combined with platinum, a is 0-2, b is 0-2, c is 0À0002-3 and a + b + c is 1-3, may be prepared by (1) reaction of the corresponding unsaturated siloxane (or silane which is subsequently hydrolysed) with a platinum halide to give a material containing at least two halogen atoms per platinum atom; (2) treating this to remove the available inorganic halogen; and (3) recovering the complex. Suitable Pt halides include PtCl 2 , organic complexes of PtCl 2 , PtCl 4 , H 2 PtCl 6 , and alkali metal haloplatinites and haloplatinates. The complexes are used to catalyse reaction between silanes and siloxanes containing SiH groups and unsaturated silanes and siloxanes. In examples H 2 PtCl 6 .6H 2 O or sodium chloroplatinite is heated with 1: 3-divinyl-tetramethyl-disiloxane in ethanol, then treated with NaHCO 3 and filtered, and the filtrate stripped of volatiles. The product is mixed with a mixture of a vinyl-terminated polydimethylsiloxane and a copolymer having SiO 2 , (CH 3 ) 3 SiO 0À5 and (CH 2 = CH)CH 3 SiO units, which cures on mixing with a resin having SiO 2 and H(CH 3 ) 2 SiO 0À5 units. |
