Abstract: A method for manufacturing polycarbonate comprises: measuring a molar ratio of a carbonic acid diester to a dihydroxy compound in a reactor system using an online analyzer; controlling a supply of at least one of the dihydroxy compound and the carbonic acid diester to the reactor system so that the measured molar ratio is maintained within a selected range; and reacting the dihydroxy compound with the carbonic acid diester to produce the polycarbonate.

Abstract: A method for manufacturing polycarbonate by melt-polycondensing bisphenol and carbonic acid diester uses as catalyst an alkali metal compound and/or alkaline earth metal compound (a). The catalyst is added to the bisphenol prior to the melt polycondensation, in an effective amount, i.e., the amount of alkali metal compound and/or alkaline earth metal compound (a) that acts effectively as a catalyst, is contained in said bisphenol, and is controlled to have the same catalytic activity as 1×10−8 to 1×10−6 mole of bisphenol disodium salt per mole of pure bisphenol A. The method conducts the reaction efficiently from the initial stage in a stable manner to obtain polycarbonate with good color, good heat stability and color stability during molding and the like.

Abstract: The present invention provides a method for manufacturing polycarbonate with excellent dwell stability (e.g., thermal stability and hue stability) during melting and molding, as well as with a low content of impurities. The present invention further relates to a method for manufacturing polycarbonate wherein the molten polycarbonate is filtered through a passivation treated metal filter.

Abstract: A method for manufacturing polycarbonate by melt-polycondensing bisphenol and carbonic acid diester uses as catalyst an alkali metal compound and/or alkaline earth metal compound (a). The catalyst is added to the bisphenol prior to the melt polycondensation, in an effective amount, i.e., the amount of alkali metal compound and/or alkaline earth metal compound (a) that acts effectively as a catalyst, is contained in said bisphenol, and is controlled to have the same catalytic activity as 1×10−8 to 1×10−6 mole of bisphenol disodium salt per mole of pure bisphenol A. The method conducts the reaction efficiently from the initial stage in a stable manner to obtain polycarbonate with good color, good heat stability and color stability during molding and the like.

Abstract: An individual wafer separating part separates batched wafers one by one from a slice base mounting beam, and then a shuttle conveyor transports the separated wafers one by one to an individual cleaning part so that the wafers can be cleaned individually. After the cleaning, a detecting part detects the thickness, breaking, chipping and remaining adhesives of the wafers. The wafers are classified in accordance with the results of the detection. Normal wafers are collected in wafer collecting parts, failed wafers are collected in a failed wafer collecting part, and wafers with remaining adhesives are collected into an adhesive remaining wafer collecting part.

Abstract: A method for determining the effective level of catalyst for the preparation of a polycarbonate polymer by a transesterification reaction is disclosed. The method involves measurement of the leaving group by-product (usually phenol) produced in a test reaction between an aromatic dihydroxy compound and a carbonic acid diester, in the presence of a known amount of transesterification catalyst. The by-product production values can be compared with by-product reference values to calculate the effective level of catalyst. This data can be used to efficiently control catalytic activity in a production scale reaction for producing polycarbonate polymer.