Abstract: Provided is a polycarbonate resin powder, including a polycarbonate-polyorganosiloxane copolymer, in which an amount of particles each having a particle diameter of 300 ?m or less in an entirety of the powder is 60 mass % or less.

Abstract: Provided is a method of producing a branched polycarbonate, including: a step (a) of subjecting an alkali aqueous solution of a dihydric phenol, phosgene, and a branching agent to a phosgenation reaction in the presence of an organic solvent to provide a reaction liquid; a step (b) of adding the alkali aqueous solution of the dihydric phenol and a polymerization catalyst to the reaction liquid obtained from the step (a) to provide a reaction liquid containing a polycarbonate oligomer; a step (c) of separating the reaction liquid containing the polycarbonate oligomer obtained in the step (b) into an organic solvent phase containing the polycarbonate oligomer and an aqueous phase; and a step (d) of causing the organic solvent phase containing the polycarbonate oligomer separated in the step (c) and the alkali aqueous solution of the dihydric phenol to react with each other to provide a reaction liquid containing the branched polycarbonate, in which a ratio (x/y) of an addition amount of the polymerization catal

Abstract: Provided is a polycarbonate resin powder, including a polycarbonate-polyorganosiloxane copolymer, in which an amount of particles each having a particle diameter of 300 ?m or less in an entirety of the powder is 60 mass % or less.

Abstract: A method of producing a polycarbonate-polyorganosiloxane copolymer, including: a step (a) of obtaining a solution containing a polycarbonate-polyorganosiloxane copolymer through use of an alkaline aqueous solution of a dihydric phenol, phosgene, a polyorganosiloxane, and an organic solvent; a step (b) of continuously or intermittently draining the solution containing the copolymer from step (a), followed by separation of the drained solution into an aqueous phase and an organic phase to provide the organic phase with copolymer; and a step (c) of concentrating the organic phase with the from step (b) to remove the organic solvent, before heating the organic phase to a boiling region in the step (c), a viscosity of the organic phase being adjusted to 70 cP or less at 35° C., the polycarbonate-polyorganosiloxane copolymer obtained by the steps (a) to (c) including a polycarbonate-polyorganosiloxane copolymer containing a specific polycarbonate block (A) and a specific polyorganosiloxane block (B).

Abstract: Provided is a polycarbonate resin powder, including a polycarbonate-polyorganosiloxane copolymer, in which an amount of particles each having a particle diameter of 300 ?m or less in an entirety of the powder is 60 mass % or less.

Abstract: Provided is a method of producing a branched polycarbonate, including: a step (a) of subjecting an alkali aqueous solution of a dihydric phenol, phosgene, and a branching agent to a phosgenation reaction in the presence of an organic solvent to provide a reaction liquid; a step (b) of adding the alkali aqueous solution of the dihydric phenol and a polymerization catalyst to the reaction liquid obtained from the step (a) to provide a reaction liquid containing a polycarbonate oligomer; a step (c) of separating the reaction liquid containing the polycarbonate oligomer obtained in the step (b) into an organic solvent phase containing the polycarbonate oligomer and an aqueous phase; and a step (d) of causing the organic solvent phase containing the polycarbonate oligomer separated in the step (c) and the alkali aqueous solution of the dihydric phenol to react with each other to provide a reaction liquid containing the branched polycarbonate, in which a ratio (x/y) of an addition amount of the polymerization catal

Abstract: Provided a process for producing a polycarbonate which comprises reacting an aqueous alkali solution of a dihydric phenol with phosgene in the presence of an organic solvent to produce a polycarbonate oligomer and subsequently polycondensing the oligomer, wherein an emulsion solution of a polycarbonate oligomer-containing organic solvent obtained in the polycarbonate oligomer production step is introduced into a coalescer to separate the emulsion solution into a polycarbonate oligomer-containing organic solvent phase and an aqueous phase, and the polycarbonate oligomer-containing organic solvent phase is subjected to polycondensation. Thus the emulsion solution of a polycarbonate oligomer-containing organic solvent obtained in the polycarbonate oligomer production step is efficiently separated to reduce the content of impurity-containing water in the oligomer for producing a polycarbonate having excellent quality and to a obtain wastewater having a low content of organic materials.

Abstract: Provided a process for producing a polycarbonate which comprises reacting an aqueous alkali solution of a dihydric phenol with phosgene in the presence of an organic solvent to produce a polycarbonate oligomer and subsequently polycondensing the oligomer, wherein an emulsion solution of a polycarbonate oligomer-containing organic solvent obtained in the polycarbonate oligomer production step is introduced into a coalescer to separate the emulsion solution into a polycarbonate oligomer-containing organic solvent phase and an aqueous phase, and the polycarbonate oligomer-containing organic solvent phase is subjected to polycondensation. Thus the emulsion solution of a polycarbonate oligomer-containing organic solvent obtained in the polycarbonate oligomer production step is efficiently separated to reduce the content of impurity-containing water in the oligomer for producing a polycarbonate having excellent quality and to a obtain wastewater having a low content of organic materials.

Abstract: Provided is a method for washing an impurities-containing polycarbonate/organic solvent solution with an aqueous washing solution, which comprises monitoring the viscosity of the mixture dispersion of the polycarbonate/organic solvent solution and the aqueous washing solution, and controlling the blend ratio of the aqueous washing solution in the system on the basis of the relation between the phase condition and the viscosity of the mixture dispersion. In the method of washing a polycarbonate/organic solvent solution with an aqueous washing solution, the amount of the washing solution to be used is reduced, and the mixture dispersion of the two solutions is stabilized at a high level of washing efficiency. The washing method is economical in practical use.

Abstract: Provided is a method for washing an impurities-containing polycarbonate/organic solvent solution with an aqueous washing solution, which comprises monitoring the viscosity of the mixture dispersion of the polycarbonate/organic solvent solution and the aqueous washing solution, and controlling the blend ratio of the aqueous washing solution in the system on the basis of the relation between the phase condition and the viscosity of the mixture dispersion. In the method of washing a polycarbonate/organic solvent solution with an aqueous washing solution, the amount of the washing solution to be used is reduced, and the mixture dispersion of the two solutions is stabilized at a high level of washing efficiency. The washing method is economical in practical use.

Abstract: According to this invention, the prior art problem that relatively many steps and a long time are required for obtaining a high quality polycarbonate of a high molecular weight by a solid phase polymerization method has been solved by subjecting a polycarbonate oligomer to swollen solid phase polymerization under an atmosphere containing a swelling solvent gas or subjecting a polycarbonate oligomer to poor solvent solid phase polymerization under a stream of a poor solvent gas.

Abstract: Provided is a method for producing a granular polycarbonate prepolymer for solid-phase polymerization, comprising dissolving a polycarbonate prepolymer in a solvent under heat, then crystallizing it by cooling, and shaping it. The grains of the granular prepolymer hardly fuse together in polymerization, and the granular prepolymer is suitable for high-speed solid-phase polymerization to give polycarbonate.

Abstract: There are disclosed a process for producing a polycarbonate through transesterification which comprises using, as a polymerization catalyst, (1) a combination of a nitrogen-containing organic basic compound and a quaternary phosphonium salt, (2) a tetraarylphosphonium salt having a specific chemical structure, or (3) a quaternary phosphonium salt having a specific chemical structure and containing a branched alkyl group; and a process for producing a polycarbonate which comprises the steps of preparing a polycarbonate prepoplymer by preliminary polymerization and thereafter polymerizing the resultant prepolymer in a state of a solid phase by the use of a quaternary phosphonium salt as a catalyst.By using any of these processes it is made possible to produce, in extremely high efficiency, a high-quality polycarbonate being excellent in appearance, heat resistance, hydrolysis resistance and the like.

Abstract: A process for producing polymer particles from an organic solvent solution of a polymer, which includes: (a) initially introducing polymer particles into a particle producing zone, (b) introducing an organic solvent solution containing an organic solvent and having a polymer concentration of 3 to 70% by weight, onto the polymer particles which are maintained in the particle producing zone, the particle producing zone not substantially containing steam, the organic solvent solution being added in an amount of not more than 250% by weight per hour based on the amount of the polymer particles which are initially held in the particle producing zone, and stirring the polymer particles under conditions in which the organic solvent would be vaporized, (c) separately introducing a poor solvent for the polymer into the particle producing zone, the poor solvent being selected from the group consisting of benzene, toluene, xylene, pentane, hexane, octane, acetone and methyl ethyl ketone, the poor solvent being in an amo

Abstract: An efficient method of obtaining polymer particles by evaporating an organic solvent while maintaining a solution of a polymer in the organic solvent in contact with polymer particles, using a simple apparatus and a simple procedure. The polymer particles (powder) produced by the method have a small particle diameter, a high bulk density, a small amount of residual solvent, and are thus excellent in quality. The method includes introducing the organic solvent solution of the polymer into a particle producing zone which does not substantially contain steam, wherein an atmosphere is maintained in which the organic solvent is vaporizable and the particles are stirred. The organic solvent is evaporated, while maintaining the solution in contact with the polymer particles. Additionally a breaker is used in combination with a mixer; a poor solvent is employed; polymer particles are recycled; or a horizontal particle producing vessel is utilized.

Abstract: Granules collected from a solution of a polycarbonate, an integrated structure of independent fine particles constituting the granules being formed at least on the surfaces of the granules; and a process for preparing the granules of the polycarbonate which comprises the steps of adding a poor solvent to the polycarbonate solution, and then agitation-granulating fine particles of the polycarbonate into the granules, while stirring involving a shear force-imparting function is carried out under heating. According to the present invention, the polycarbonate or the like can be collected from its organic solvent solution as the granules having good drying properties.

Abstract: A process for the production of a polycarbonate powder comprising introducing an organic solvent solution of polycarbonate and steam into a mixing nozzle and obtaining the polycarbonate powder from a mixture ejected from the mixing nozzle, wherein the organic solvent solution contains 3 to 45% by weight of the polycarbonate, and the ratio of the weight of steam/the weight of an organic solvent in the organic solvent solution is 1/10 to 1/5.

Abstract: A phase difference compensation film formed of a polycarbonate, which can be used in a liquid crystal display and which shows a decreased change in retardation caused by a temperature change at a stretch forming time due to the use of a polycarbonate having a branched structure and having a viscosity-average molecular weight of 40,000 or less as the above polycarbonate.

Abstract: A polycarbonate having desirable color tone or transparency, as well as desirable heat resistance and water resistance, in which the amounts of residual metals in the polycarbonate are 10 ppm or less in total of Fe, Cr and Mo and 50 ppm or less in total of Ni and Cr. The polycarbonate is obtained by transesterification of (A) a dihydroxy compound and (B) a carbonic diester in a reactor made of a metallic material containing at least one metal selected from the group consisting of Fe, Cr, Mo, Ni and Cu, and controlling the water content in the reactor to 500 ppm or less.

Abstract: A process for producing polycarbonates which comprises transesterifying by reacting (A) at least one compound selected from the group consisting of aromatic dihydroxy compounds, aliphatic dihydroxy compounds, bisesters of aromatic dihydroxy compounds, bisesters of aliphatic dihydroxy compounds, carbonates of aromatic dihydroxy compounds and carbonates of aliphatic dihydroxy compounds, with (B) at least one compound selected from the group of diaryl carbonates, dialkyl carbonates, and alkylaryl carbonates, at a transesterification temperature of 100.degree. C. to 330.degree. C. in the presence of an inert solvent in an amount of 1 to 60% by weight based on the total of the theoretical amount of polycarbonate produced from the said compounds (A) and (B) and the amount of the inert solvent. According to the present invention, a polycarbonate which is excellent in color tone (transparency), heat resistance, and water resistance can be efficiently and simply produced at a low cost.