Copolycarbonate and composition containing the same

A polycarbonate composition comprising:

• a polycarbonate;
• and
• a copolycarbonate,
• wherein the copolycarbonate comprises:
• an aromatic polycarbonate-based first repeating unit;
• and aromatic polycarbonate-based second repeating units having siloxane bonds,
• wherein 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 (⅛ inch, Notched Izod) is 1.01 to 1.30, and the impact strength at room temperature is 840 to 1000 J/m, and
• wherein the second repeating units comprise a repeating unit represented by Chemical Formula 2 and a repeating unit represented by Chemical Formula 3:
• in Chemical Formula 2,
• each of X1 is independently C1-10 alkylene,
• each of R5 is independently hydrogen;
• C1-15 alkyl unsubstituted or substituted with oxiranyl, oxiranyl-substituted C1-10 alkoxy, or C6-20 aryl;
• halogen;
• C1-10 alkoxy;
• allyl;
• C1-10 haloalkyl;
• or C6-20 aryl, and
• n is an integer of 10 to 200,
• in Chemical Formula 3,
• each of X2 is independently C1-10 alkylene,
• each of Y1 is independently hydrogen, C1-6 alkyl, halogen, hydroxy, C1-6 alkoxy, or C6-20 aryl,
• each of R6 is independently hydrogen;
• or C1-15 alkyl unsubstituted or substituted with oxiranyl, oxiranyl-substituted C1-10 alkoxy, or C6-20 aryl;
• halogen;
• C1-10 alkoxy;
• allyl;
• C1-10 haloalkyl;
• or C6-20 aryl, and
• m is an integer of 10 to 200.