Abstract: A process for preparing an end-capped polycarbonate comprises melt reacting an aromatic dihydroxy compound, a carbonic acid diester, and optionally a catalyst in a prepolymerization vessel to form a polycarbonate product; transferring the polycarbonate product from the prepolymerization vessel; mixing the polycarbonate product with an end-capping agent under hermetic seal at a pressure of at least about 760 mm Hg; and transferring the polycarbonate product and end-capping agent mixture to a postpolymerization vessel to endcap the polycarbonate product.

Abstract: Polycarbonate having increased end-cap levels is made by adding an end-capping agent to the polycarbonate, preferably after the polycarbonate has reached a number-average molecular weight of about 2,000 to 15,000 Dalton.

Abstract: The present invention provides a composition comprising polycarbonate wherein the polycarbonate has a very low Fries content (e.g., above 5 ppm and below 360 ppm). The present invention also provides a polycarbonate having a very low Fries content which is made by the melt process. This polycarbonate has high ductility and high impact strength. The invention also provides a method for making these compositions. Another aspect of the invention is an optical disk comprising polycarbonate having a very low Fries content which is made by the melt process. Such optical disks resist breakage due to bending.

Abstract: A process for preparing an end-capped polycarbonate comprises melt reacting an aromatic dihydroxy compound, a carbonic acid diester, and optionally a catalyst in a prepolymerization vessel to form a polycarbonate product; transferring the polycarbonate product from the prepolymerization vessel; mixing the polycarbonate product with an end-capping agent under hermetic seal at a pressure of at least about 760 mm Hg; and transferring the polycarbonate product and end-capping agent mixture to a postpolymerization vessel to endcap the polycarbonate product.

Abstract: Polycarbonate having increased end-cap levels is made by adding an end-capping agent to the polycarbonate, preferably after the polycarbonate has reached a number-average molecular weight of about 2,000 to 15,000 Dalton. The end-capping agent has the formula: wherein R1 is a phenyl, phenoxy, benzyl, or benzyloxy and R2 is selected from the group consisting of C1-C30 alkyl, C1-C30 alkoxy, C6-C30 aryl, C6-C30 aryloxy, C7-C30 aralkyl, and C7-C30 aralkyloxy.

Abstract: This specification describes an optical polycarbonate composition obtained by the melt polycondensation of a bisphenol and a carbonic diester in the presence of an alkaline compound catalyst, wherein said optical polycarbonate composition comprises (i) a compound expressed by the following Formula [A] in an amount of 30 to 2000 ppm; (ii) a compound expressed by the following Formula [B] in an amount of 30 to 4000 ppm; and (iii) a compound expressed by the following Formula [C] in an amount of 80 to 8000 ppm. The polycarbonate composition has a viscosity average molecular weight of between 12,000 and 18,000, and the portion with a molecular weight (as measured by GPC) of 1000 or less accounts for 0.5 to 1.5 wt %.

Abstract: This specification discloses polycarbonates for optical use. These polycarbonates are prepared by reacting a bisphenol and carbonic diester in the presence of an alkaline compound catalyst.

Abstract: The specification describes a method for manufacturing dialkyl carbonate by reacting carbon monoxide, oxygen and alcohol in the presence of a catalyst. The catalyst is produced by reacting together ingredients including a cupric halide and an alkoxide compound of a group III through VII metal.

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: To provide a method with which a polycarbonate can be manufactured efficiently without any pipe clogging or foreign material admixture in the course of the continuous manufacture of a polycarbonate. A continuous method for manufacturing a polycarbonate, characterized in that, in the continuous manufacture of a polycarbonate by transesterification from a dihydroxy compound and a carbonic diester, the crystallization of a polycarbonate lower polycondensate produced in the intermediate stage of a polycondensation reaction whose intrinsic viscosity (IV) measured at 20° C. in methylene chloride is between 0.1 and 0.4 dL/g is suppressed by setting the temperature to be at least 230° C. on the surface of the reactor equipment in contact with the polycarbonate lower polycondensate.

Abstract: The specification describes a method for manufacturing dialkyl carbonate by reacting carbon monoxide, oxygen and alcohol in the presence of a catalyst. The catalyst is produced by reacting together ingredients including a cupric halide and an alkoxide compound of a group III through VII metal.

Abstract: The manufacture of polycarbonates can be accomplished via an ester interchange reaction of a dihydroxy compound and a carbonic acid diester. The method, which can be a single or multi-stage process wherein the total amount of alkali metal compounds and alkaline earth metal compounds contained as impurities is 1×10−7 moles or less per mole of dihydroxy compound used as raw materials, and the catalyst employed is an ammonium and/or phosphonium compound, a compound which decomposes or volatilizes at a temperature of 100 to 300° C., and/or an alkali metal phosphorous containing inorganic salt and/or alkaline earth metal phosphorous-containing inorganic salt.

Abstract: A polycarbonate production method, characterized in that a dihydroxy compound and a carbonic acid diester are subjected to melt polycondensation in the presence of a catalyst containing an alkali metal compound and/or alkaline-earth metal compound in an amount of 1×10−8 to 1×10−5 mol per mole of dihydroxy compound; wherein a sulfonic acid ester compound and a transition metal scavenger are also added to the reaction product; and wherein the polycarbonate is treated at a reduced pressure.

Abstract: To provide a method with which a polycarbonate can be manufactured efficiently without any pipe clogging or foreign material admixture in the course of the continuous manufacture of a polycarbonate. A continuous method for manufacturing a polycarbonate, characterized in that, in the continuous manufacture of a polycarbonate by transesterification from a dihydroxy compound and a carbonic diester, the crystallization of a polycarbonate lower polycondensate produced in the intermediate stage of a polycondensation reaction whose intrinsic viscosity (IV) measured at 20° C. in methylene chloride is between 0.1 and 0.4 dL/g is suppressed by setting the temperature to be at least 230° C. on the surface of the reactor equipment in contact with the polycarbonate lower polycondensate.

Abstract: To provide a method with which a polycarbonate can be manufactured efficiently without any pipe clogging or foreign material admixture in the course of the continuous manufacture of a polycarbonate.

Abstract: A method is provided for the preparation of polycarbonates by the reaction of a diaryl carbonate, such as DPC and a dihydric phenol, such as BPA. The method utilizes the steps of successively processing the diaryl carbonate and the dihydric phenol in a melt in a first reaction stage, a second reaction stage and at least a first polymerization stage, and shifts the processing conditions such that the desired low viscosity/high end-cap product is obtained. This is achieved by having the ratio of diaryl carbonate to dihydric phenol in the melt prior to the first reaction stage greater than 1.08; and by controlling the temperature and residence time in the first polymerization stage to provide a polycarbonate product having a melt flow rate at 250° C. of greater than 10 g/min and an end-cap level of at least 90%. The method of the invention can be used in a linear manufacturing process, in which there is one product produced.

Abstract: Increasing the endcap level to a level greater than about 90% for Optical Quality (OQ) Melt Polycarbonate significantly reduces the as-molded static charge for injection molded parts for Optical Disc applications. The use of resins with higher endcap levels in combination with antistatic additives provides a highly robust formulation suitable for even the most demanding emerging formats as Digital Versatile Disc (DVD) and in all commercial Optical media molding machines. Thus, optical quality polycarbonates are prepared by performing a base-catalyzed polymerization of a diaryl carbonate and a dihydric phenol under conditions effective to produce a polycarbonate product having an endcap level of 90% or greater.

Abstract: An efficient method for manufacturing a dialkyl carbonate from CO, O2, and an alcohol which uses a catalyst comprising: (i) a cupric halide; and (ii) a compound capable of producing a copper halide alkoxide by reaction with a cupric halide.

Abstract: The specification provides a method for the manufacture of a high-quality optical polycarbonate that contains few inorganic or organic impurities or other microparticles, and that has a superior hue. Specifically, the specification provides a method for the manufacture of a polycarbonate by the melt polycondensation of a bisphenol and a carbonic diester, wherein the molten mixture of a bisphenol and a carbonic diester is filtered with a membrane filter made of a fluororesin, after which melt polycondensation is conducted.