Disclosed is a polycarbonate composition including a polycarbonate; and a copolycarbonate, where the copolycarbonate includes an aromatic polycarbonate-based first repeating unit; and aromatic polycarbonate-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 copolycarbonate has an impact strength at room temperature of 840 to 1000 J/m as measured at 23 C. in accordance with ASTM D256 ( inch, Notched Izod), and the copolycarbonate satisfies Equation 1: ##STR00001##
TS/TS.sub.00.80.[Equation 1] The copolycarbonate in the composition provides an improved chemical resistance and impact strength simultaneously.

Disclosed is a copolycarbonate including an aromatic polycarbonate-based first repeating unit; and one or more aromatic polycarbonate-based second repeating units having siloxane bonds represented by Chemical Formula 2 and Chemical Formula 3: ##STR00001##
The copolycarbonate provides improved impact strength at low-temperature and improved YI (yellow index) simultaneously.

Disclosed is a copolycarbonate including aromatic polycarbonate-based repeating units represented by Chemical Formula 1 and Chemical Formula 2; and aromatic polycarbonate-based repeating units having siloxane bonds represented by Chemical Formula 3 and Chemical Formula 4: ##STR00001##
copolycarbonate provides improved impact strength at low-temperature, improved YI (yellow index), and improved melt index simultaneously.

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 resin composition comprising a copolycarbonate in which a specific siloxane compound is introduced in a main chain of the polycarbonate, and a UV stabilizer. Since the present copolycarbonate resin composition has excellent weather resistance, the article prepared by using this composition exhibits less deteriorated surface quality and physical properties caused by ultraviolet rays or the like when exposed to the outside.

The present invention relates to copolycarbonates and a molded article comprising the same. The copolycarbonate according to the present invention has a structure in which a specific siloxane compound is introduced in a main chain of the polycarbonate, and thus has characteristics of providing excellent residence heat stability.

A method for producing a polycarbonate copolymer which has siloxane constituent units represented by any of formulae (1-1) to (1-4) and prescribed polycarbonate constituent units, the method having a polymerization step for polymerizing a silane-based compound selected from among a prescribed diaryloxysilane compound, a prescribed dialkoxysilane compound and a prescribed silicon compound, a carbonate compound and a diol compound such as an aromatic diol compound or an alicyclic diol compound in the presence of a transesterification catalyst. The polymerization step is carried out in a molten state under reduced pressure while removing alcohols derived from the carbonate compound. ##STR00001##

The present invention relates to a polycarbonate composition including a polycarbonate and an impact reinforcing agent, and an inorganic filler to improve a mechanical property thereof, and a copolycarbonate to solve a problem of appearance defect caused by including the inorganic filler.

A polysiloxane compound is disclosed which has siloxane constituent units represented by any of formulae (1-2) to (1-4)

##STR00001##

and prescribed polycarbonate constituent units. Also disclosed are articles comprising the polysiloxane compound, including molded bodies and optical lenses, as well as methods of manufacturing the polysiloxane compounds and of manufacturing articles comprising the polysiloxane compounds.

In an example of a method disclosed herein, a polycarbonate with a hydrophilic surface is formed. An ether substituted dichlorosilane, phosgene, and a Bisphenol reactant are polymerized to form a polycarbonate including a hydrolyzable silane in its backbone chain. The hydrolyzable silane includes an alkoxy group attached to a silicon atom. The alkoxy group on the hydrolyzable silane is converted to a more hydrophilic functional group to form the polycarbonate with the hydrophilic surface.