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 a melt index (MI) of 3 to 9 g/10min as measured in accordance with ASTM D1238 (300 C., 1.2 kg conditions), and a transparency of 87 to 91% as measured in accordance with ASTM D1003 (layer thickness of 3 mm): ##STR00001## The copolycarbonate in the composition exhibits an excellent transparency and a high spiral flow while having a high impact strength at room temperature and a low melt index.

The present invention relates to copolycarbonates and a composition comprising the same. The copolycarbonate according to the present invention has a structure in which specific siloxane compounds are introduced in the main chain of polycarbonate and thus exhibits the effects of improving impact strength at room temperature, impact strength at low-temperature and melt index.

The present invention relates to copolycarbonates and a composition comprising the same. The copolycarbonate according to the present invention has a structure in which specific siloxane compounds are introduced in the main chain of polycarbonate and thus exhibits the effects of improving impact strength at room temperature, impact strength at low-temperature and melt index.

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.

Condensation of fluoro-substituted and silyl-substituted monomers provides polymers suitable for use, e.g., as engineering polymers. A monomer composition is condensed in the presence of a basic catalyst. The monomer composition contains a compound of formula FXF and a compound of formula (R.sup.1).sub.3SiZSi(R.sup.1).sub.3, and forms an alternating XZ polymer chain and a silyl fluoride byproduct. X has the formula -A(R.sup.2-A)n-; each A is SO.sub.2, C(O), or Het; R.sup.2 is an organic moiety; n is 0 or 1; Het is an aromatic nitrogen heterocycle; Z has the formula -L-R.sup.3-L; each L is O, S, or N(R.sup.4); and each R.sup.3 is an organic moiety, and R.sup.4 comprises H or an organic moiety.

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 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.