The present invention relates to a copolycarbonate and a composition comprising the same, and more specifically to a technique for improving flame retardance and chemical resistance while maintaining inherent impact strength and melt index of the copolycarbonate, by comprising a branched repeating unit in the copolycarbonate structure.

The present invention relates to a copolycarbonate and a composition comprising the same, and more specifically to a technique for improving flame retardance and chemical resistance while maintaining inherent impact strength and melt index of the copolycarbonate, by comprising a branched repeating unit in the copolycarbonate structure.

The present invention relates to a process for preparing aromatic polycarbonates, comprising the step of reacting bisphenols with dithiocarbonates or selenium analogues thereof in the presence of a catalyst. It further relates to the use of dithiocarbonates or selenium analogues thereof as transesterifying reagents for the preparation of polycarbonates.

The present invention relates to a process for preparing aromatic polycarbonates, comprising the step of reacting bisphenols with dithiocarbonates or selenium analogues thereof in the presence of a catalyst. It further relates to the use of dithiocarbonates or selenium analogues thereof as transesterifying reagents for the preparation of polycarbonates.

Disclosed is a polycarbonate composition including a polycarbonate; and a copolycarbonate, where the copolycarbonate includes: an aromatic polycarbonate-based first repeating unit; and aromatic polycatbonate-based second repeating units having siloxane bonds, which include a repeating unit represented by Chemical Formula 2 and a repeating unit represented by Chemical Formula 3, where the ratio of an impact strength at room temperature and an impact strength at low-temperature (impact strength at room temperature/impact strength at low-temperature) as measured at 23 C. and 30 C., respectively, in accordance with ASTM D256 ( inch, Notched Izod) is 1.01 to 1.30, and the impact strength at room temperature is 840 to 1000 J/m: ##STR00001##

Disclosed is a polycarbonate composition including a polycarbonate; and a copolycarbonate, where the copolycarbonate includes: an aromatic polycarbonate-based first repeating unit; and aromatic polycatbonate-based second repeating units having siloxane bonds, which include a repeating unit represented by Chemical Formula 2 and a repeating unit represented by Chemical Formula 3, where the ratio of an impact strength at room temperature and an impact strength at low-temperature (impact strength at room temperature/impact strength at low-temperature) as measured at 23 C. and 30 C., respectively, in accordance with ASTM D256 ( inch, Notched Izod) is 1.01 to 1.30, and the impact strength at room temperature is 840 to 1000 J/m: ##STR00001##

Polycarbonate polymers comprising non-aromatic cyclic groups bonded with carbonate linking groups are described. A portion of the non-aromatic cyclic groups comprise a substituent having siloxane repeat units. Representative formulas of the substituents having siloxane repeat units include CH.sub.2CH.sub.2Si(R.sup.4).sub.2(OSi(R.sup.4).sub.2R.sup.5, and CH[Si(R.sup.4).sub.2(OSi(R.sup.4).sub.2).sub.mR.sup.5]CH.sub.3; wherein m is the number of siloxane repeat units; and R.sup.4 and R.sup.5 are independently alkyl, aryl, aralkyl or aralkylene. The polycarbonate polymer C typically comprises a high concentration of carbonate linking group, for example in an amount of at least 85 or 90 mol % or greater N based on the total linking groups of the polymer. Also described are compositions comprising the polycarbonate polymer and methods of making.

Polycarbonate polymers comprising non-aromatic cyclic groups bonded with carbonate linking groups are described. A portion of the non-aromatic cyclic groups comprise a substituent having siloxane repeat units. Representative formulas of the substituents having siloxane repeat units include CH.sub.2CH.sub.2Si(R.sup.4).sub.2(OSi(R.sup.4).sub.2R.sup.5, and CH[Si(R.sup.4).sub.2(OSi(R.sup.4).sub.2).sub.mR.sup.5]CH.sub.3; wherein m is the number of siloxane repeat units; and R.sup.4 and R.sup.5 are independently alkyl, aryl, aralkyl or aralkylene. The polycarbonate polymer C typically comprises a high concentration of carbonate linking group, for example in an amount of at least 85 or 90 mol % or greater N based on the total linking groups of the polymer. Also described are compositions comprising the polycarbonate polymer and methods of making.

The objective of the present invention is to provide a method for producing a polycarbonate safely and efficiently. A method for producing a polycarbonate is characterized in comprising the step of irradiating a light to a composition comprising a C.sub.1-4 halogenated hydrocarbon, the specific diol compound and the specific base in the presence of oxygen.

The objective of the present invention is to provide a method for producing a polycarbonate safely and efficiently. A method for producing a polycarbonate is characterized in comprising the step of irradiating a light to a composition comprising a C.sub.1-4 halogenated hydrocarbon, the specific diol compound and the specific base in the presence of oxygen.