Patent ID: 8288456

Claim:
A process for producing an impact-modified polycarbonate composition filled with carbon nanotubes, wherein said process produces reduced degradation in molecular weight of said polycarbonate, said process comprising: (i) in a first step, mixing a Component C comprising carbon nanotubes with Component B comprising a rubber-containing vinyl copolymer and/or Component D comprising a rubber-free vinyl copolymer on a twin screw extruder, to obtain a masterbatch, wherein: the rubber-containing vinyl copolymer of Component B comprises at least one graft polymer of B.1. 5 to 95 wt. % of at least one vinyl monomer on B.2. 95 to 5 wt. % of at least one graft base with glass transition temperatures of <10Â° C., wherein the B.1 monomer consists of a mixture of B.1.1 50 to 99 parts by weight vinyl aromatics and/or vinyl aromatics substituted in the nucleus and/or (meth)acrylic acid (C 1 -C 8 ) alkyl esters, and B.1.2 1 to 50 parts by weight vinyl cyanides and/or (meth)acrylic acid (C 1 -C 8 ) alkyl esters, anhydrides and imides of unsaturated carboxylic acids; and Component D is selected from the group consisting of thermoplastic vinyl (co)polymers D.1 and terephthalates D.2, wherein D.1 vinyl (co)polymers comprise D.1.1 50 to 99 parts by weight vinyl aromatics and/or vinyl aromatics substituted in the nucleus and/or (meth)acrylic acid (C 1 -C 8 ) alkyl esters, and D.1.2 1 to 50 parts by weight vinyl cyanides and/or (meth)acrylic acid (C 1 -C 8 ) alkyl esters, and/or unsaturated carboxylic acids and/or anhydrides and imides of unsaturated carboxylic acids; and (ii) in a second step, mixing the masterbatch produced from step (i) with Component A comprising an aromatic polycarbonate and/or aromatic polyester carbonate and optionally with Component B and/or Component D and optionally with an additive on a twin screw extruder.