Abstract: The present invention provides a room-temperature-curable polyorganosiloxane composition which can become a silicone rubber with matte surface and is free from deterioration in physical properties. Specifically, the room-temperature-curable polyorganosiloxane composition comprises: (A) 100 parts by weight of a substantially straight-chain polyorganosiloxane having a viscosity of 20 to 1,000,000 centistokes at 25° C., and having a molecular chain terminal being sealed with a silanol group or a silicon atom-bonded hydrolyzable group; (B) 0.

Abstract: A therapeutic bed of a radiotherapeutic system including a radioactive ray irradiator which radiates radioactive rays for treatment of an affected portion of a patient, includes a top board on which the patient to be inspected is laid, a support base rotatably mounted on a floor of a therapeutic room, an elevating mechanism supported by the support base and supporting the top board in a vertically elevating fashion, the elevating mechanism comprising a hydraulic link mechanism of two-stage link structure, a casing covering the elevating mechanism and being constructed to be vertically contractable and expandable in association with a vertical motion of the elevating mechanism, and a hydraulic device for driving the elevating mechanism. The hydraulic driving device is disposed apart from the elevating mechanism and particularly embedded in a floor of a therapeutic room.

Abstract: A process for preparing organopolysiloxane emulsion comprised of dispersed particles having an average particle size of 0.5.mu. or less, comprising emulsifying a liquid organopolysiloxane with use of an emulsifying agent by means of a composite emulsifying apparatus equipped with(A) a stirring means having a stirring blade capable of stirring contents of a container at a low speed over the whole of the container, and at least one stirring means selected from(B) a disc type stirring means capable of rotating at a high speed and having tooth-like projections on its peripheral edge, and(C) a stirring means having a stator and a turbine blade disposed in the inside of the stator and capable of rotating at a high speed. According to this process, an organopolysiloxane having a high viscosity up to 500,000 cP can be emulsified to prepare an emulsion of high stability.

Abstract: The reactive injection molding of a urethane-based resin composition according to the invention is performed by admixing the polyol compound as one of the reactants of the urethane-based resin with a specific organopolysiloxane as an internal mold release agent so that the molding process can be performed without application of an external mold release agent to the metal mold. The organopolysiloxane is characterized by two types of substituent groups bonded to the silicon atoms, of which the first type is --C.sub.x H.sub.2x OR', R' being a monovalent hydrocarbon group of 8 to 30 carbon atoms free from chain end unsaturation and x being 0-4, and the second type is --C.sub.y H.sub.2y (OC.sub.n H.sub.2n).sub.m OH, y being 1-4, n being 2-4 and m being 0-45.

Abstract: Fine spherical particles of cured silicone elastomer can be prepared by spray-drying an aqueous emulsion of a curable organopolysiloxane composition having a particle diameter not exceeding 20 .mu.m. The organopolysiloxane composition comprises preferably an organopolysiloxane having silicon-bonded vinyl groups, an organohydrogenpolysiloxane having silicon-bonded hydrogen atoms and a platinum catalyst so that curing of the composition may take place in the emulsion before spray-drying or in the course of spray-drying by the addition reaction between the silicon-bonded vinyl groups and the silicon-bonded hydrogen atoms.

Abstract: A polyorganosiloxane-based high-impact thermoplastic graft copolymer superior in impact resistance, light resistance, surface gloss and color fastness produced by the emulsion graft polymerization of at least one vinyl monomer on an emulsion-polymerized polyorganosiloxane which consists of90 to 99.8 mole % of an organosiloxane unit represented by the formulaR'.sub.2 SiO.sub.2/2 (I)wherein R' is the same or different and denotes methyl, ethyl, propyl, or phenyl,0.1 to 10 mole % of a unit derived from a graft-linking agent, said unit being represented by the formula ##STR1## wherein; R.sup.2 denotes methyl, ethyl, propyl, or phenyl; n denotes a number of 0, 1, and 2; and p denotes a number of 1 to 6, and0.1 to 10 mole % of a unit derived from a tetrafunctional silane crosslinking agent, said unit being represented by the formulaSiO.sub.

Abstract: The inventive method for forming a cured film on a substrate surface comprises coating the surface with a room temperature curable organosiloxazane polymer comprising, in a molecule, (a) at least one organosiloxane unit represented by the unit formula (a) at least one organosiloxane unit represented by the unit formulaR.sup.1.sub.a SiO.sub.(4-a)/2,and (b) at least one organosilazane unit represented by the unit formulaR.sup.2.sub.b Si(NR.sup.3).sub.(4-b)/2,in which R.sup.1, R.sup.2 and R.sup.3 are each a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, not all of them being simultaneously hydrogen atoms, and the subscripts a and b are each a positive integer of 1, 2 or 3 with the proviso that a and b cannot be simultaneously equal to 3, in a molecule and subjecting the coating film to exposure to a moisture-containing atmosphere. The method is useful for forming a surface-protecting film or for imparting surface releasability.

Abstract: The invention provides a method for protecting the surface of various kinds of shaped articles made of an organic polymeric material such as rubbers, leathers, woods, plastics and the like against weathering caused by exposure to ultraviolet light, ozone, moisture, etc. The method comprises providing the surface with a coating layer of a specific organopolysiloxane composed of difunctional, tetrafunctional and nonofunctional siloxane units in a limited molar proportion of 50-85%, 10-30% and 5-20%, respectively.

Abstract: The invention provides an efficient method for releasing a shaped body of a polymeric material such as a foamed polyurethane resin from a mold in which the body has been molded without the problem of adhesion to the mold. The inventive method comprises admixing the polymeric material with a specific organopolysiloxane represented by the structural formulaR.sup.1.sub.3 Si--O--SiR.sup.2.sub.2 --O).sub.m (SiR.sup.2 A--O).sub.n SiR.sup.1.sub.3,in which A is a substituent group represented by the general formula --C.sub.x H.sub.2x --O--R, R being a monovalent hydrocarbon group having 8 to 30 carbon atoms but free from terminal unsaturation and x being zero or a positive integer not exceeding 4, R.sup.1 is a monovalent hydrocarbon group or the same group as A, R.sup.2 is a hydrogen atom or the same group as R.sup.1, and m and n are each zero or a positive integer with the proviso that at least one group denoted by A is contained in a molecule of the organopolysiloxane.

Abstract: The invention provides a novel organopolysiloxane-containing aqueous emulsion composition which, upon removal of water by drying at room temperature, can give a cured rubbery elastomer having excellent mechanical properties and exhibiting strong adhesion to the substrate on which it has been cured. The inventive composition is prepared by blending (A) an aqueous emulsion of an organopolysiloxane having silicon-bonded hydroxy groups and emulsified in water by use of an anionic surface active agent, (B) a mixture of a reaction product of a carboxylic acid anhydride with an amino-functional organosilane and a colloidal silica in the form of an aqueous suspension and (C) a curing catalyst in limited proportions.