Polycarbonate-polyorganosiloxane copolymer and a resin composition

A polycarbonate-polyorganosiloxane copolymer comprising in a main chain:

• (a) a repeating unit I represented by the formula (I):
• ##STR18## wherein R.sup.1 and R.sup.2 are, respectively, a hydrogen atom or an alkyl group having 1 to 4 carbon atoms and are the same or different from each other;
• (b) a repeating unit II represented by the formula (II):
• ##STR19## wherein R.sup.3 and R.sup.4 are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms and are the same or different from each other and
• X.sup.1 to X.sup.4 are each a halogen atom;
• (c) a structural unit III represented by the formula (III):
• ##STR20## wherein R.sup.5 to R.sup.8 are each a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a phenyl group and are the same or different from each other,
• R.sup.9 and R.sup.10 are each an organic group containing an aliphatic group or an aromatic group,
• A is --O--, --NH-- or a single bond and
• k is an integer of 1 to 100;
• and a terminal group IV at least at one terminal end of the copolymer, the terminal group (IV) being a polyhalogenophenoxy group represented by the formula (IV):
• ##STR21## wherein X.sup.5 is a halogen atom, m is an integer of 1 to 5 and when m is 2 or more each X.sup.5 are the same or different from each other;
• the repeating unit II in the main chain being in an amount of 1 to 10 mol % based on the total contents of the repeating unit I and the repeating unit II;
• the structural unit III being in an amount of 0.01 to 1.3 weight % based on the total contents of the repeating unit I, the repeating unit II and the structural unit III;
• and the copolymer having a viscosity average molecular weight of 10,000 to 50,000.