Abstract: A silicone rubber composition comprising an organopolysiloxane and a curing catalyst for the organopolysiloxane. The releasing property of the composition is significantly improved by the addition of N,N'-alkylene bisamide having not less than 10 carbon atoms. The composition is particularly effective for molding in a mold or covering a wire core.

Abstract: The organopolysiloxane composition is useful as a potting or encapsulating material having a gel-like consistency for protecting electronic components even at an extremely low temperature as is encountered in the space industry. The composition is basically of the type in which crosslinks are formed by the addition reaction between silicon-bonded vinyl groups in an organopolysiloxane and silicon-bonded hydrogen atoms in an organohydrogenpolysiloxane but the outstanding cold resistance of the gel-like material obtained from the composition is imparted by incorporating specific silethylene-containing units of the unit formula OSiMe--CH.sub.2 CH.sub.2 --SiMe.sub.2 O.sub.0.5 into the organopolysiloxane in a specified molar content.

Abstract: Provided herein is an ultraviolet-curable gel composition which comprises an organopolysiloxane as a principal component which is represented by the general structural formula below. ##STR1## where R.sup.1 is a C.sub.4-25 monovalent organic group containing therein 1 to 2 vinyl functional groups; R.sup.2 is a C.sub.1-18 monovalent organic group having no vinyl group capable of addition polymerization; R.sup.3 is a C.sub.2-4 divalent hydrocarbon group; R.sup.4 is a C.sub.1-9 substituted or unsubstituted hydrocarbon group of the same or different kind; a is an integer of 1 to 3; and n is an integer of 5 to 500.

Abstract: A polyvinyl chloride resin-based composition can be imparted with improved thermal stability of compounding the same with a polygylcerin in an amount of 0.01 to 0.5% by weight based on the resin even when the composition is compounded with a heat stabilizer having relatively low effectiveness although the use of such a heat stabilizer is desirable in respect of the physiological inertness. Similar improving effects on the thermal stability of a polyvinyl chloride resin-based composition can be obtained when the resin is prepared by suspension-polymerizing vinyl chloride monomer in an aqueous medium containing a polyglycerin.

Abstract: An improved sol-gel method is proposed for the preparation of a transparent silica gel block, in which a deposit of fine silica particles having a controlled particle diameter as prepared by hydrolyzing an alkoxy silane in the presence of ammonia is dispersed in a silica sol solution prepared in an acidic condition and settled therein to form a structure of closest-packing prior to gelation, drying, sintering and vitrification so that silica glass blocks can be obtained with low volume shrinkage from the wet gel in an improved yield without cracks, bubbles and haziness. The improvement can be further enhanced when two separately prepared deposits of silica particles having larger and smaller particle diameters are dispersed as combined in the silica sol solution, especially, when the particle diameter in one deposit is not exceeding 22.5% of that in the other deposit.

Abstract: Cycloalkyl silane compound such as cyclohexyl methyl dichlorosilane can be efficiently prepared by the photochemically induced hydrosilylation reaction. For example, an equimolar mixture of cyclohexene and methyl dichlorosilane with admixture of a catalytic amount of an alcoholic solution of, chloroplatinic acid, is irradiated at a temperature up to 70.degree. C. with ultraviolet light so that the hydrosilylation reaction takes place and proceeds almost to completeness without deactivation of the platinum catalyst to give the desired product in a yield of 90% or even higher.

Abstract: An electroluminescent device of the dispersion type exhibiting high brightness of electroluminescence and having excellent heat resistance and flexibility, and usable as a backlighting unit for liquid crystal displays and as a plane light-emitting body, can be prepared by using, as the matrix material of the particulate electroluminescent material, a specific cyanoalkyl group-containing organopolysiloxane represented by the average unit formula R.sup.1.sub.a R.sup.2.sub.b SiO.sub.(4-a-b)/2, in which R.sup.1 is a cyanoalkyl group having 3 to 5 carbon atoms, R.sup.2 is a monovalent hydrocarbon group, a is 0.8 to 1.8 and b is 0 to 1.0 with the proviso that a+b is 1.1 to 1.98.

Abstract: A method for preparing a cyclic isocyanuric ester having organosilicon groups which comprises thermally treating an isocyanic ester for addition reaction in the presence of an alkali metal hydroxide or alkoxide. By the above reaction, a cyclic trimer of the starting isocyanic ester can be selectively obtained. The catalyst can be readily removed from the reaction system.

Abstract: A room temperature-curable organopolysiloxane composition is proposed which is useful as a material for imprinting or blocking of forms of, for example, medical and dental prostheses without the problem of curing retardation or incomplete curing. The composition comprises a vinyl-containing organopolysiloxane, organohydrogenpolysiloxane, platinum catalyst, inorganic filler, liquid paraffin or petrolatum and antioxidant. The antioxidant serves to protect the liquid paraffin or petrolatum from oxidation to produce oxidized compounds which may deactivate the platinum catalyst to cause curing retardation or incomplete curing.

Abstract: An epoxy resin composition which comprises a curable epoxy resin, a curing agent, an inorganic filler, and at least one copolymer selected from copolymers obtained by an addition reaction between aromatic polymers containing one or more epoxy groups and one or more alkenyl groups and the specific organopolysiloxanes; copolymers obtained by an addition reaction between aromatic polymers containing one or more epoxy groups and the specific amino group-containing organopolysiloxanes.

Abstract: Organosilicon compounds of the following formula, or hydrolyzates thereof, ##STR1## ps in which Rhu 1 l and Rhu 2 l are independently a hydrogen atom or an alkyl group having from 1 to 8 carbon atoms, m is an integer of from 1 to 8, and n is an integer of from 1 to 3. The compound is useful as a vulcanizing agent particularly for vulcanizable elastomer compositions comprising inorganic fillers.

Abstract: An epoxy resin composition which is adapted for use as an encapsulator of electronic or electric parts and which comprises an epoxy resin and a curing agent for the epoxy resin. A modified polymer obtained by reaction between an aromatic polymer and a fluorine-containing material is added to the epoxy resin, so that good characteristic properties are imparted to the resultant cured product.

Abstract: In place of the conventional rod-in-tube method, a novel method is proposed for the preparation of a high-quality base material of quartz glass for optical fibers according to which a glassy rod composed of the core portion of a larger refractive index and the first cladding layer of a smaller refractive index is first prepared by silica soot deposition by the flame hydrolysis of a gaseous silicon compound followed by dehydration and vitrification, and then the glassy rod is covered with a layer of further silica soot deposition which is subsequently converted to the second cladding layer by vitrification. The inventive base material for optical fibers is excellent in the geometry relative to the diameter of the core portion and thickness of the cladding layer as well as concentricity of the core and the cladding.

Abstract: A foamable silicone rubber composition, comprising:(A) a polyorganosilphenylenesiloxane copolymer represented by Formula (I): ##STR1## wherein R.sup.1 and R.sup.2 are each a particular monohydrocarbon group, and a and h are each an integer of 1 or more and have the relation of 1.gtoreq.a/b.gtoreq.0.05 and a+b.gtoreq.100,(B) an organosilicon compound containing a particular organosiloxy unit having a hydroxyl group,(C) a polyorganohydrogenosiloxane having at least two particular units having an Si--H bond, and(D) a platinum family metal catalyst.This composition can provide a foam with good mechanical strength.

Abstract: A novel method for accelerating growth of a plant in agriculture and forestry is proposed in which an organosilicon compound .omega.-carboxyalkylsilicon sesquioxide, e.g. 2-carboxyethylsilicon sesquioxide, of the unit formulaHOOC(CH.sub.2).sub.n SiO.sub.1.5,in which n is a positive integer of 1 to 4, is applied to the plant directly or to the soil in which the plant is growing. The metal salts or complexes of the above compound as well as the precursor compounds thereof readily convertible to the silsesquioxide compound by hydrolysis are also effective.

Abstract: A solvent-free releasing silicone composition for rendering surfaces non-adherent which gives a cured film having desirable slip factor, toughness, and high-speed peel characteristics without sacrificing its inherenty merits such as curability, uniformity in peel resistance, and the residual adhesive strength employs a diorganovinylpolysiloxane having trivinylsilyloxy as one end group and either a vinyldimethylsilyl or trimethylsilyl group as the other end group.

Abstract: A process for manufacturing an organic silazane polymer which comprises reacting ammonia with a mixture of methyldichlorosilane, methyltrichlorosilane and dimethyldichlorosilane to obtain an ammonolysis product. The ammonolysis product is polymerized in the presence of a basic catalyst capable of deprotonation to obtain an organic silazane polymer. The silazane polymer may be further melted, shaped and infusibilized. The thus infusibilized product is finally sintered to obtain a ceramic material.

Abstract: A process for manufacturing an organic silazane polymer which comprises reacting ammonia with a mixture of at least one compound selected from the group consisting of organic silicon compounds of the following formulae (I) and (II) ##STR1## and at least one compound selected from the group consisting of organic silicon compounds of the following formula (III) ##STR2## in which R represents hydrogen, chlorine, bromine, methyl radical, ethyl radical, phenyl radical or vinyl radical, R.sub.1 represents hydrogen or methyl radical, R.sub.2 represents hydrogen, methyl radical, ethyl radical, phenyl radical or vinyl radical and X represents chlorine or bromine; to obtain an ammonolysis product. The ammonolysis product is polymerized in the presence of a basic catalyst capable of deprotonation to obtain an organic silazane polymer. The silazane polymer may be further melted, shaped and infusibilized. The thus infusibilized product is finally sintered to obtain a ceramic material.

Abstract: A composition for coating glass fiber articles such as glass sleeve, glass cloth, glass roving, glass tape, glass mat or glass nonwoven fiber, comprising(a) a diorganopolysiloxane end-blocked with a divinylmonoorganosilyl or trivinylsilyl radical at both ends,(b) a sufficient amount of an organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms per molecule to provide at least 0.5 silicon-bonded hydrogen atoms per vinyl radical in component (a), and(c) a catalytic amount of platinum or a platinum compound.

Abstract: Disclosed are a block-graft copolymer comprising a polymer block having a repetitive unit represented by General Formula: ##STR1## wherein A represents an organopolysiloxane chain, a polyalkylene oxide chain, a polyalkylene-imine chain, a polyacrylate chain or a polyacryloyl chain,and a process for producing the same. This block-graft copolymer can have various performances such as an oxygen enrichment performance, an ion concentration property, a capability of forming a complex with a metal salt and a biocompatibility, depending on the kind of graft polymer chains.