Abstract: Particulate silica is prepared by feeding a gas mixture of an organohalosilane gas, a flammable gas capable of generating water vapor when burned, and a free oxygen-containing gas to a reaction chamber through a multiple-tube burner, whereby the organohalosilane is subjected to flame hydrolysis and oxidation reaction. The amount of the flammable gas fed is 0.5-9 mol per mol of the organohalosilane and such that the amount of water vapor resulting from combustion of the flammable gas is 1-6 times the stoichiometric amount, and the gas mixture is fed to the center tube of the burner such that it may have a linear velocity at the outlet of 50-120 m/sec, calculated in the standard state. The resulting silica has a surface area of 100-400 m2/g and a narrow particle size distribution of primary particles and ensures the transparency of silicone rubber filled therewith.

Abstract: In an industrial process for preparing organohalosilanes by reacting metallic silicon particles with an organohalide in the presence of a copper catalyst, a contact mass composed of the metallic silicon and the catalyst further contains an effective amount of a phosphine chalcogenide compound. The invention drastically increases the silane formation rate and the utilization of silicon without lowering the selectivity of useful silane.

Abstract: In an industrial process for preparing organohalosilanes by reacting metallic silicon particles with an organohalide in the presence of a copper catalyst, a contact mass composed of the metallic silicon and the catalyst further contains an effective amount of a phosphonium compound having on the molecule at least one group of the formula: [R2R3R4P—]+Y− wherein R2, R3 and R4 each are a monovalent hydrocarbon group and Y is a halogen atom or acid group. The invention drastically increases the silane formation rate and the utilization of silicon without lowering the selectivity of useful silane.

Abstract: In an industrial process for preparing organohalosilanes by reacting metallic silicon particles with an organohalide in the presence of a copper catalyst, a contact mass composed of the metallic silicon and the catalyst further contains an effective amount of a phosphine chalcogenide compound. The invention drastically increases the silane formation rate and the utilization of silicon without lowering the selectivity of useful silane.

Abstract: In an industrial process for preparing organohalosilanes by reacting metallic silicon particles with an organohalide in the presence of a copper catalyst, a contact mass composed of the metallic silicon and the catalyst further contains an effective amount of a phosphonium compound having on the molecule at least one group of the formula: [R2R3R4P—]+Y− wherein R2, R3 and R4 each are a monovalent hydrocarbon group and Y is a halogen atom or acid group. The invention drastically increases the silane formation rate and the utilization of silicon without lowering the selectivity of useful silane.

Abstract: In a process for preparing oganohalosilanes by reacting metallic silicon particles with an organohalide in the presence of a copper catalyst, a contact mass composed of the metallic silicon and the catalyst further contains a minute, but effective amount of a catalytic metal powder which has been produced by an atomizing technique. The process is successful in drastically increasing a formation rate without lowering the selectivity of useful silane.

Abstract: In a process for preparing oganohalosilanes by reacting metallic silicon particles with an organohalide in the presence of a copper catalyst, a contact mass composed of the metallic silicon and the catalyst further contains a minute, but effective amount of a catalytic metal powder which has been produced by an atomizing technique. The process is successful in drastically increasing a formation rate without lowering the selectivity of useful silane.

Abstract: Particulate silica is prepared by feeding a gas mixture of an organohalosilane gas, a flammable gas capable of generating water vapor when burned, and a free oxygen-containing gas to a reaction chamber through a multiple-tube burner, whereby the organohalosilane is subjected to flame hydrolysis and oxidation reaction. The amount of the flammable gas fed is 0.5-9 mol per mol of the organohalosilane and such that the amount of water vapor resulting from combustion of the flammable gas is 1-6 times the stoichiometric amount, and the gas mixture is fed to the center tube of the burner such that it may have a linear velocity at the outlet of 50-120 m/sec, calculated in the standard state. The resulting silica has a surface area of 100-400 m2/g and a narrow particle size distribution of primary particles and ensures the transparency of silicone rubber filled therewith.

Abstract: When oganohalosilanes are prepared by charging a reactor with a contact mass containing a metallic silicon powder, a copper catalyst and a co-catalyst, and introducing an organohalide-containing gas into the reactor to effect the direct reaction, the catalyst and/or co-catalyst used in the contact mass is obtained by mixing particles of the catalyst and/or co-catalyst with finely divided silica, and applying shear forces to the mixture for mutually rubbing the particles, thereby producing the catalyst and/or co-catalyst having finely divided silica fused to surfaces thereof. The invention is successful in producing organohalosilanes at a significantly improved formation rate without reducing the proportion of diorganodihalosilane.

Abstract: When oganohalosilanes are prepared by charging a reactor with a contact mass containing a metallic silicon powder, a copper catalyst and a co-catalyst, and introducing an organohalide-containing gas into the reactor to effect the direct reaction, the catalyst and/or co-catalyst used in the contact mass is obtained by mixing particles of the catalyst and/or co-catalyst with finely divided silica, and applying shear forces to the mixture for mutually rubbing the particles, thereby producing the catalyst and/or co-catalyst having finely divided silica fused to surfaces thereof. The invention is successful in producing organohalosilanes at a significantly improved formation rate without reducing the proportion of diorganodihalosilane.

Abstract: When oganohalosilanes are prepared by charging a reactor with a contact mass containing a metallic silicon powder and a copper catalyst, and introducing an organohalide-containing gas into the reactor to effect the direct reaction, a poly(organo)phosphino compound is added to the contact mass. The invention is successful in producing organohalosilanes at a significantly improved production rate without reducing the selectivity of useful silane.

Abstract: When oganohalosilanes are prepared by charging a reactor with a contact mass containing a metallic silicon powder and a copper catalyst, and introducing an organohalide-containing gas into the reactor to effect the direct reaction, a metal complex of an organophosphino compound is added to the contact mass. The invention is successful in producing organohalosilanes at a significantly improved production rate without reducing the selectivity of useful silane.

Abstract: A contact mass for use in the synthesis of organohalosilanes is prepared by adding metallic copper particles to metallic silicon particles, and rubbing the particles against each other under high shear forces in a non-oxidizing atmosphere, thereby forming a metallic copper thin film on the surface of the metallic silicon particles in a spot pattern or entirely. The contact mass is capable of reducing the time required for activation and has an extended lifetime.

Abstract: A polymerization apparatus used, particularly, in suspension polymerization of vinyl chloride, comprising a polymerization vessel (1) having a substantially cylindrical inner space, said inner space of said polymerization vessel being provided with a plurality of baffles (5) comprising vertically extending pipes, and serpentine pipelines (6) each of which is placed between two adjacent baffles and is extended in a serpentine fashion along the polymerization vessel inner wall from the lower part to the upper part of the polymerization vessel, and a refrigerant being passed through said baffles and said serpentine pipelines. High-cooling performance can be obtained, a high-speed reaction in a large-sized polymerization vessel becomes possible, and a stable polymerization reaction can be carried out. A high-quality and uniform polymer that has few fish eyes and has a high bulk specific gravity can be obtained.

Abstract: The present invention provides polylactic compositions effecting an excellent mold releasability upon processing and significantly improved elongation at break and impact strength without affecting the transparency. Also provided is a shrink film which decomposes under the natural environment and has excellent transparency, flexibility, shrinkability and mold releasability upon processing by applying the polylactic acid composition to a shrink film. There is provided a biodegradable polymer composition comprising 100 parts by weight of polylactic acid and 5 to 70 parts by weight of EVA. Further, a biodegradable polymer composition is provided comprising the polymer composition with one or more additives selected from the group consisting of 0.05 to 5 parts by weight of a lubricant, 1 to 50 parts by weight of plasticizer, 0.5 to 5 parts by weight of thermal stabilizer and 0.05 to 5 parts by weight of mold releasing agent. These biodegradable polymer compositions are applied to shrink films.

Abstract: A composition comprising polylactic acid and 0.05 to 5 parts by weight of silicone oil per 100 parts by weight polylactic acid, having improved mechanical properties.

Abstract: A vinyl chloride polymer is produced by subjecting vinyl chloride or a monomer mixture made up mainly of vinyl chloride to suspension polymerization in an aqueous medium using a polymerization apparatus equipped with a polymerization vessel. The polymerization apparatus used comprises a polymerization vessel (1) having a substantially cylindrical inner space, said inner space of said polymerization vessel being provided with a plurality of baffles (5) comprising vertically extending pipes, and serpentine pipelines (6) each of which is placed between two adjacent baffles and is extended in a serpentine fashion along the polymerization vessel inner wall from the lower part to the upper part of the polymerization vessel, and a refrigerant being passed through said baffles and said serpentine pipelines. High-cooling performance can be obtained, a high-speed reaction in a large-sized polymerization vessel becomes possible, and a stable polymerization reaction can be carried out.

Abstract: A polymerization apparatus equipped with a circuit made up of a polymerization vessel, a heat exchanger placed outside said polymerization vessel, and a circulation pipeline extending from said polymerization vessel and returning to said polymerization vessel through said heat exchanger, a branch pipeline being connected to said circulation pipeline through a ball valve comprising a spherical valve element and a valve body for housing said spherical valve element, wherein the valve body of said ball valve is joined directly to said circulation pipeline, and a method of producing a polymer of a monomer having an ethylenically unsaturated double bond by using said apparatus. Scale and polymers in the form of blocks can be prevented from mixing with the reaction mixture.

Abstract: A polymerization apparatus that is equipped with a circulation path for the flow of a reaction mixture that comprises a polymerization vessel, a heat exchanger arranged outside said polymerization vessel, and a pipeline that is extended from said polymerization vessel, is returned to said polymerization vessel through said heat exchanger, and is provided with a strainer in the course thereof, wherein the surface of a filter provided in said strainer that is located upstream has rodlike projections, and a method of producing a polymer of a monomer having an ethylenically unsaturated double bond by using said apparatus. Scale and polymers in the form of blocks can be prevented from mixing into the reaction mixture. Therefore, where the obtained sheet is molded into a sheet or the like, fish eyes can be reduced and even if the polymerization is repeated, clogging of the tubes of the heat exchanger and dropping in the flow velocity of the reaction mixture can be prevented.