Abstract: A multi stage process for the production of polycarbonates having low monomer content is disclosed. The process entails, in sequence, (i) transesterifying in the melt at least one dihydroxyaryl compound with at least one diaryl carbonate in the presence of at least one onium catalyst to produce a polycondensate that contains monomers, (ii) introducing into the polycondensate an inhibitor in an hypostoichiometric amount in relation to the catalyst and (iii) reducing in a finishing reactor the content of monomers in said polycondensate. The polycarbonate thus produced is characterized in that it contains less than 350 ppm of diphenyl carbonate, less than 40 ppm of 2,2-bis-(4-hydroxyphenyl)propane and less than 150 ppm of phenol.

Abstract: A process for stripping volatile constituents from polymer melts is disclosed. The process entails introducing the polymer melt into a horizontally oriented cylindrical device that contains a plurality of perforated disks rotating about a common horizontally oriented, externally driven shaft bringing the melt and disks into contact in a manner calculated to constantly renew the surface of the melt to be stripped. Also disclosed is an apparatus suitable for the process.

Abstract: A process for stripping volatile constituents from polymer melts is disclosed. The process entails introducing the polymer melt into a horizontally oriented cylindrical device that contains a plurality of perforated disks rotating about a common horizontally oriented, externally driven shaft bringing the melt and disks into contact in a manner calculated to constantly renew the surface of the melt to be stripped. Also disclosed is an apparatus suitable for the process.

Abstract: A multi stage process for the production of polycarbonates having low monomer content is disclosed. The process entails, in sequence, (i) transesterifying in the melt at least one dihydroxyaryl compound with at least one diaryl carbonate in the presence of at least one onium catalyst to produce a polycondensate that contains monomers, (ii) introducing into the polycondensate an inhibitor in an hypostoichiometric amount in relation to the catalyst and (iii) reducing in a finishing reactor the content of monomers in said polycondensate. The polycarbonate thus produced is characterized in that it contains less than 350 ppm of diphenyl carbonate, less than 40 ppm of 2,2-bis-(4-hydroxyphenyl)propane and less than 150 ppm of phenol.

Abstract: A process for making a thermoplastic molding composition comprising (i) forming a vertically falling stream of molten polymer, and (ii) bringing at least one additive in solid or liquid states, in solution, in the form of a dispersion or in suspension into contact with at least a part of the surface of said stream and to introduce the additive in said stream to produce combined stream, and (iii) introducing the combined stream into a pump to form a pre-mix and (iv) introducing the premix into a mixer to form a homogeneous polymer melt. The entraining stream is then introduced to a pump to form a pre-mix which is then introduced to a mixer to form a homogeneous polymer melt. The process results in a compositions having advantageous material properties.

Abstract: The invention relates to a continuous method for producing polycarbonates by transesterifying diaryl carbonates with dihydroxyaryl compounds in the presence of quaternary onium compounds. The invention also relates to polycarbonates produced thereby and products produced from said polycarbonates.

Abstract: A process for making a high molecular weight (co)polycarbonate resin is disclosed. The process entails (i) obtaining at least one member selected from the group low molecular weight residue (weight average molecular weight 15,000 to 30,000) of aromatic (co)polycarbonate production, waste of (co)polycarbonate production, remainders of (co)polycarbonate production and (co)polycarbonate recyclate (ii) melting the said member in a suitable vessel to obtain a melt and (iii) feeding the melt into a reactor optionally along with at least one bisphenol or oligocarbonate having terminal OH groups and further optionally with a transesterification catalyst, and (iv) subjecting the melt to transesterification reaction at a temperature of 250 to 350° C., at a pressure below 5 mbar and residence time of 0.02-4 hours.

Abstract: A continuous process for producing oligocarbonate is disclosed. The process entails in sequence the steps of a) reacting a dihydroxyaryl compound with a diaryl carbonate in the presence of a catalyst to obtain a melt and avoiding removal of released monohydroxyaryl compound and b) withdrawing the monohydroxyaryl compound by flash evaporation and c) heating the melt obtained under vacuum in an evaporator equipped with sump receiver and d) repeating at least once steps b) and then c) each at gradually increased temperatures and lowered pressures.

Abstract: A branched melt-polymerized polycarbonate having pronounced non-Newtonian flow behavior is disclosed. The polycarbonate is suitable for preparing molding compositions and the preparation of a variety of molded articles.

Abstract: The invention relates to a continuous method for producing polycarbonates by transesterifying diaryl carbonates with dihydroxyaryl compounds in the presence of quaternary onium compounds. The invention also relates to polycarbonates produced thereby and products produced from said polycarbonates.

Abstract: A process for preparing a melt transesterification catalyst is disclosed. The process entails (i) obtaining a phenol adduct of phosphonium phenolatein the form of crystalline solid and (ii) storing the solid phenol adductin a closed container at relative humidity of 30 to 70 % and at temperature of −30 to 50° C. The thus prepared catalyst is suitable in the production of polycarbonate in the melt transesterification process.

Abstract: A process for producing polycarbonate is disclosed. The process entails using equipment having leakage rate less than 10−3 liter He×mbar/sec. The polycarbonate thus produced is characterized by its enhanced thermal stability.

Abstract: The invention relates to a novel polycarbonate and its use a material in the production of molded articles and semifinished products, especially for transparent articles such as data memories or radio compact discs, slabs, cellular sheets, films, housings, panes, especially panes for motor vehicles, diffusion glasses, but also for electrical applications or the constructions of houses.

Abstract: A process for the production of phosphonium phenolates is disclosed. The process entails reacting a phosphonium halide and phenol in an aqueous alkaline solution.

Abstract: Solid particles containing 10 to 90 parts by weight of a dihydroxy compound and 10 to 90 parts by weight of a carbonic acid ester are disclosed. Also disclosed is a process for the production of these particles, an apparatus suitable for the process and a method for their use in production of polycarbonate by transesterification of carbonic acid esters with dihydroxy compounds.

Abstract: A process for producing polycarbonate is disclosed. The process entails transesterification of at least one carbonic ester with a mixture that contains dihydroxyl compound and phenol. The amount of bisphenol A in the mixture is 10 to 100 mol % relative to the amount of dihydroxyl compound and phenol is present in the mixture in an amount of 0.1 to 200% relative to the weight of bisphenol A.

Abstract: An improvement to the melt transesterification reaction of diaryl carbonate with dihydroxy aryl compound is disclosed.

Abstract: A melt-polymerized polycarbonate is disclosed. The polycarbonate has a shear thinning ratio (y) that is defined by the limiting values of the following equation c+axb>y>−c+axb  (Q) wherein y≧1, c=0.3 to 0.1, b=14.831±0.05 to 0.02, a=0.1262±0.005 to 0.003 and x is the relative viscosity of the polycarbonate. The polycarbonate exhibits a flow behavior similar to that of a linear polycarbonate of comparable molecular weight obtained by the interface polymerization process.

Abstract: A process for preparing a melt transesterification catalyst is disclosed. The process entails (i) obtaining a phenol adduct of phosphonium phenolatein the form of crystalline solid and (ii) storing the solid phenol adductin a closed container at relative humidity of 30 to 70% and at temperature of −30 to 50° C. The thus prepared catalyst is suitable in the production of polycarbonate in the melt transesterification process.

Abstract: A process for producing polycarbonate is disclosed. The process entails obtaining an oligocarbonate produced by transesterification of diaryl carbonate with dihydroxyaryl compound in the presence of catalysts and introducing the oliogocarbonate into a reactor that enables continuous formation of free films at a rate higher than 10. The reactor including a horizontal cylinder equipped with a heating jacket, at least one vapor outlet, a feed nozzle an outlet nozzle, a rotatable cylindrical basket having a cylindrical perforated wall and annular discs positioned at intervals around the periphery of said basket and along the length thereof, and means for rotating said basket, the interior of said basket including no central shaft, the diameter of the cylindrical basket corresponding to about ⅔ of the diameter of the horizontal cylinder, and said discs being formed of perforated sheet metal.