摘要:
This invention relates to a novel low-temperature dielectric silicone gel which is the reaction product of a polyorganosiloxane consisting essentially of Me.sub.2 SiO, MeSiO.sub.1.5, Me.sub.3 SiO.sub.0.5 and Me.sub.2 ViSiO.sub.0.5 ; an organohydrogensiloxane and a platinum catalyst.
摘要:
A vaporized mixture of a platinum catalyst in the amount of 0.01 to 2 p.p.m. platinum, an acetylenic alcohol and a siloxane compound having at least three silicon-bonded hydrogen atoms per molecule is passed through a tube such as a stainless steel tube heated at 210.degree.C. to 450.degree.C. to produce an olefinic siloxane compound which is, below 100.degree.C., an inhibitor for the reaction between the acetylenic alcohol and the siloxane compound having at least three silicon-bonded hydrogen atoms in the presence of platinum.
摘要:
The compatibility between high consistency fluorinated and non-fluorinated polydiorganosiloxanes is increased, with a resultant increase in the physical-properties of elastomers prepared from mixtures of these polymers, by blending the polymers together with a reinforcing silica filler that is reacted with both fluorinated and non-fluorinated liquid polydiorganosiloxanes as filler treating agents. The high consistency polydiorganosiloxanes contain at least two alkenyl radicals per molecule and are cured by a hydrosilation reaction.
摘要:
The presence of an incompatible liquid, polydiorganosiloxane wherein from 1 to 30 percent of the siloxane units contain an ethylenically unsaturated hydrocarbon radical in high-consistency organosiloxane compositions that cure by a platinum-catalyzed hydrosilation reaction substantially improves the tear strength and elongation of cured elastomers prepared from these compositions.
摘要:
Liquid diorganovinylsiloxy terminated polydiorganosiloxanes wherein at least 50 percent of the hydrocarbon radicals bonded to silicon contain at least one perfluorinated carbon atom are prepared by polymerizing the corresponding diorganocyclosiloxane(s) at a temperature of from 25.degree. to 150.degree. C. under superatmospheric pressure and in the presence of a controlled amount of water and a catalytically effective amount of ammonia. The resultant silanol terminated polydiorganosiloxane is reacted with a hexaorganodisilazane containing a vinyl radical bonded to each of the two silicon atoms.
摘要:
The curable compositions of this invention comprise a solubilized vinyl-containing fluorosilicone gum, a curing agent for the gum, a platinum-containing hydrosilation catalyst, a treated reinforcing silica filler, and a volatile solvent for the gum and curing agent. The organosilicon compound used to treat the silica filler is critical to obtaining a homogeneous curable composition free of agglomerated particles, and is a hydroxyl terminated polydiorganosiloxane containing silicon-bonded fluorocarbon radicals.
摘要:
Polyorganosiloxane gels exhibiting a resistance to discoloration and hardening at temperatures of 100.degree. C. and above can be prepared by the reaction of a polydiorganosiloxane containing silicon-bonded fluorinated hydrocarbon radicals with an organohydrogensiloxane containing at least three silicon-bonded hydrogen atoms per molecule in the presence of a platinium containing catalyst. The resistance to heat induced hardening and discoloration is achieved by preparing the polydiorganosiloxane by the ammonia catalyzed polymerization of at least one cyclic fluorine-containing diorganosiloxane followed by reaction of the resultant silanol terminated polymer with a hexaorganodisilazane containing a vinyl radical bonded to each of the two silicon atoms.The reactants preferably contain 3,3,3-trifluoropropyl radicals to achieve a resistance to softening and/or solubilization of the cured gel in the presence of hydrocarbon fuels.
摘要:
Reinforcing silica treated with short chain linear amidosiloxane of the formula ##STR1## provides a useful reinforcing filler for silicone elastomers. Silicone elastomer bases manufactured using this treated silica can be cured by organic peroxides or the combination of organohydrogensiloxane and platinum catalyst. When the later curing system is used, the cured products exhibit considerable retention of physical properties upon exposure to elevated temperatures for a significant period of time.
摘要:
A method for making a fluorinated polydiorganosiloxane base composition and the composition prepared thereby. The base composition can be addition cured using a platinum-metal group catalyst and an organohydrogensiloxane crosslinker to form a fluorosilicone elastomer having improved resiliency and compression set properties.
摘要:
Certain liquid polydiorganosiloxanes wherein each molecule contains at least one sequence of 2 or more vinyl radicals bonded to non-terminal silicon atoms extend the working time at 25.degree. C. of organosiloxane compositions that cure by a platinum catalyzed hydrosilation reaction without adversely affecting the cure rate of the composition at temperatures of about 100.degree. C. and above. The polydiorganosiloxane is prepared by the acid-catalyzed polymerization of the corresponding cyclic polydiorganosiloxanes in the presence of a chain-terminating organosilicon reactant.