Abstract: Microparticles of a hydrosilylation catalyst encapsulated in a thermoplastic resin are prepared by forming a solution containing the hydrosilylation catalyst and a thermoplastic resin with a glass-transition temperature or softening point of 40.degree. to 200.degree. C. dissolved in a solvent, and then spraying this solution as droplets into a hot gas current in order to volatilize the solvent while solidifying said thermoplastic resin during entrainment of the droplets in the gas current.

Abstract: Storage stable and gel-free organosiloxane compositions in the form of flowable powders are prepared by blending a high consistency polydiorganosiloxane into a quantity of fluidized reinforcing filler that is heated to a temperature of from 100.degree. to 200.degree. C. prior to or immediately following introduction of the polydiorganosiloxane. When silica is the reinforcing filler, the filler is typically treated with an anti-creping agent either prior to or during this blending process. The resultant mixture is heated while being subjected to shearing forces that reduce its average particle size to achieve a flowable powder.

Abstract: The compression set values of elastomers prepared from organosiloxane compositions that cure by a platinum-catalyzed hydrosilylation reaction are substantially reduced by the presence in said compositions of a phthalocyanine compound or a metal derivative of such a compound, where the metal is copper, nickel, cobalt or iron.

Abstract: A class of neutral, hydrogen-free liquid or waxy perfluorinated cotelomers is described. The cotelomers contain more than 50% weight of fluorine and are derived from chlorotrifluoroethylene and a member selected from the group consisting of one perfluorinated olefin, one perfluorinated alkylvinyl or polyoxaalkylvinyl ether, where said alkyl radical contains from 1 to 6 carbon atoms and said polyoxaalkyl group contains from 2 to 10 carbon atoms; mixtures of two perfluorinated olefins containing from 2 to 6 carbon atoms, with the proviso that one is tetrafluoroethylene, and a mixture of tetrafluoroethylene with one of said perfluorinated alkylvinyl ethers. The present cotelomers exhibit excellent lubricity, transparency, low compressibility, low refractive index and a high resistance to electrical discharge. The cotelomers are particularly useful as lubricants and hydraulic fluids, as optical media and as insulating materials.

Abstract: Non-friable siloxane gels which can be used for gel dressings and in medical prostheses are made from compositions comprising (A) alkenyl-containing polydiorganosiloxanes; (B) hydrosilicon compounds having at least 3 Si-H groups; (C) SiH end-blocked polydiorganosiloxanes and (D) a catalyst. These compositions cure rapidly at room temperature having a ratio (RHAlk) of SiH:Si-Alkenyl of from 3:1 to 20:1, the percentage of silicon-bonded H atoms provided by (C) not being less than 81.36-(3.6.times.RHAlk) and having a value of from 10% to 90%.

Abstract: Novel propargyl esters are prepared by a base catalyzed condensation reaction of propargyl esters of carboxylic acids containing a labile hydrogen atom at the alpha position relative to the carboxy group, and a terminal aromatic hydrocarbon radical that is linked to the carboxy group through a sequence of carbon atoms containing at least one carbon-to-carbon double bond. If more than one of these double bonds are present they form a conjugated sequence. Novel organosilicon compounds are prepared by reacting these propargyl esters with an organohydrogensilane or an organohydrogensiloxane. The organosilicon compounds undergo a reversible crosslinking reaction in the presence of ultraviolet light.

Abstract: The disadvantages associated with using a platinum-catalyzed hydrosilylation reaction to prepare sponge products from curable organosiloxane compositions can be overcome by microencapsulating the platinum-containing catalyst in a thermoplastic organic or organosilicone polymer.

Abstract: The tear strength of cured organosiloxane elastomers can be increased and the compression set value reduced without adversely affecting other physical properties if the composition used to prepare the elastomer is curable by a platinum-catalyzed hydrosilation reaction and contains a mixture of two liquid diorganoalkenylsiloxy terminated polydiorganosiloxanes, one of which constitutes from 96 to 99.5 percent by weight of said mixture and contains the alkenyl radicals only at the terminal positions. The second polydiorganosiloxane contains both terminal alkenyl radicals and from 1 to 5 mole percent of alkenyl radicals on non-terminal repeating units.

Abstract: Chemically inert fluorinated organosilicon compounds for use as, e.g., lubricants are described corresponding to the formulaeR.sup.1.sub.4 SiorR.sup.2.sub.3 Si(R.sup.3 SiR.sup.4.sub.2).sub.z R.sup.23,where z is from 1 to 4, inclusive, at least three of the R.sup.1 radicals, at least two of the terminal R.sup.2 radicals, and preferably one of the non-terminal R.sup.2 radicals are derived from(a) monovalent alkyl-terminated fluorotelomers of chlorotrifluoroethylene or(b) monovalent alkyl-terminated fluorocotelomers of chlorotrifluoroethylene and either hexafluoropropene or mixtures of hexafluoropropene and tetrafluoroethylene, andR.sup.3 represents an alkenyl-terminated divalent fluorotelomer or cotelomer, and the value of z is from 1 to 4, inclusive.

Abstract: The combination of (1) long term storage stability, (2) a relative short cure time at temperatures below about 150.degree. C. and (3) cohesive bonding of the cured elastomer to a variety of substrates is achieved in a one-part organosiloxane composition that cures by a platinum-catalyzed hydrosilylation when the composition includes an acetylenic alcohol containing at least eight carbon atoms as the catalyst inhibitor and, as the adhesion promoter, an alkoxysilane containing an epoxy group and a polyorganosiloxane containing an average of at least one silicon-bonded hydroxyl group and at least one silicon-bonded vinyl radical per molecule. The concentrations of catalyst and adhesion promoter are within specified limits.

Abstract: The curable resin composition of the present invention consists of a curable resin having uniformly dispersed therein particles of a cured silicone rubber obtained from an organosiloxane composition curable by a platinum-catalyzed hydrosilation reaction, wherein said organosiloxane composition contains reaction products of an ethylenically unsaturated epoxy compound and an ethylenically unsaturated aromatic compound with the organohydrogenpolysiloxane present in said organosiloxane composition. Either or both of the epoxy compound and the aromatic compound can be prereacted with a portion of the silicon-bonded hydrogen atoms of the organohydrogenpolysiloxane.

Abstract: The present invention provides microencapsulated liquid or solubilized curing catalysts for one-part heat curable organosiloxane compositions. Compositions containing these exhibit long-term storage stability yet cure rapidly when heated above the melting point of the encapsulating polymer. At least a portion of these microcapsules are less than one micron in diameter, and substantially all are less than about three microns in diameter. Compositions containing the preferred platinum group metals as catalysts are optically transparent.The microencapsulated curing catalysts of this invention are prepared by the photoinitiated polymerization of at least one solubilized hydroxyl-containing ethylenically unsaturated organic compound in the presence of a photoinitiator for the polymerization of said compound, an optional surfactant, and a liquid or solubilized curing catalyst for organosiloxane compositions.

Abstract: The present invention is based on the discovery that a cured organic or organosiloxane gel will enter and flow through a conduit to a dispensing location as a coherent, homogeneous portion of material when (1) one end of the conduit is immersed in the gel (2) a sufficient pressure differential is applied between the surface of the gel and the interior of the conduit to cause the gel to enter and at least partially fill a portion of the conduit, and (3) sufficient pressure is then applied within the conduit to cause the gel to flow in the conduit to at least one dispensing location where the gel is withdrawn from the conduit as an integral, homogeneous stream of material.

Abstract: A group of substituted benzotriazoles unexpectedly improves the physical properties, particularly the tensile strength and tear strength, of peroxide cured organosiloxne elastomers.

Abstract: N-triorganosilylsulfonimidoyl halides are prepared using a novel series of reactions from compounds of hexavalent sulfur selected from amides, chlorides and anhydrides of organosulfonic acids. More specifically, the present method relates to the reaction of an N-triorganosilyl- or an N,N-bis(triorganosilyl)-sulfonamide with a triorganodihalophosphorane to form the corresponding sulfonimidoyl halide.

Abstract: The present invention provides microencapsulated liquid or solubilized curing catalysts for one-part heat curable organosiloxane compositions. The curing catalysts are prepared by the photoinitiated polymerization of at least one solubilized hydroxyl-containing ethylenically unsaturated organic compound in the presence of a photoinitiator for the polymerization of said compound, an optional surfactant, and a liquid or solubilized curing catalyst for organosiloxane compositions. The curing agent is in the form of coordination complex with an ethylenically or acetylenically unsaturated organic compound and the solvent for the polymerization reaction is a mono- or polyhydric alcohol. At least a portion of the present microcapsules are less than one micron in diameter, and substantially all are less than about three microns in diameter. Compositions containing the preferred platinum group metals as catalysts are optically transparent.

Abstract: One-part organosiloxane composition curable by a platinum-catalyzed hydrosilation reaction contain the catalyst encapsulated within finely divided particles of a cured silicone rubber. The compositions are storage-stable for up to several days at room temperature, yet cure relatively rapidly when heated.

Abstract: Organosiloxane compositions that cure in the presence of ultraviolet radiation comprise a polymethylsiloxane containing a specified combination of mono-, di- and trifunctional siloxane units, an amount of a mercaptoalkyl-substituted polyorganosiloxane or an organic mercaptan in an amount sufficient to cure the composition to a soft, repairable gel and an amount of a photoinitiator sufficient to initiate curing of the composition in the presence of ultraviolet radiation. The cured compositions are particularly useful as coatings and encapsulants to protect electronic devices against the deleterious effects of materials present in the environment adjacent to said devices.

Abstract: Storage stable, one part organosiloxane compositions that cure upon heating by a platinum-catalyzed hydrosilation reaction comprise, in addition to the organosiloxane reactants, a platinum-containing hydrosilation catalyst that is microencapsulated within one or two layers of thermoplastic organic polymers. The microcapsules are formed using known techniques.

Abstract: The silicone rubber obtained by curing in the presence of a platinum-containing catalyst a composition comprising an organopolysiloxane containing a plurality of lower alkenyl radicals and a organohydrogensiloxane consisting essentially of R.sub.3 SiO.sub.1/2 units, R.sub.2 SiO units, RHSiO units, and RSiO.sub.3/2 units in a specified molar ratio is uniquely suitable as the coating material for the press roll in the fixing assembly of an electrophotographic copier.