Flame retardant thermoplastic resin composition with improved compatibility

A flame retardant thermoplastic resin composition comprising:

• (A) about 20 or more but less than about 100% by weight of a polycarbonate resin;
• (B) more than about 0 but not more than about 80% by weight of a branched (meth)acrylic copolymer resin, wherein said branched (meth)acrylic copolymer resin (B) is a copolymer or a mixture of copolymers of (b1) an aromatic methacrylate, an aliphatic methacrylate, or a mixture thereof represented by the following Chemical Formula 1, Chemical Formula 2, or a mixture thereof, (b2) optionally a mono-functional unsaturated monomer selected from the group consisting of methacrylic acid ester monomers, acrylic acid ester monomers, unsaturated carboxylic acid monomers, acid anhydride monomer, hydroxyl group containing ester monomer, and mixtures thereof, and (b3) a branch-inducing monomer:
• wherein m is an integer from 0 to 10, and X comprises a cyclohexyl group, a phenyl group, a methylphenyl group, a methylethylphenyl group, a propylphenyl group, a methoxyphenyl group, a cyclohexylphenyl group, a chlorophenyl group, a bromophenyl group, a phenylphenyl group, or a benzylphenyl group;
• wherein m is an integer from 0 to 10, Y is oxygen(O) or sulfur(S), and Ar comprises a cyclohexyl group, a phenyl group, a methylphenyl group, a methylethylphenyl group, a methoxyphenyl group, a cyclohexylphenyl group, a chlorophenyl group, a bromophenyl group, a phenylphenyl group, or a benzylphenyl group;
• and
• (C) about 1 to about 50 parts by weight of a flame retardant, per 100 parts by weight of a base resin comprising (A)+(B),
• wherein the branched (meth)acrylic copolymer resin (B) has a weight average molecular weight of about 1,000,000 to about 3,500,000.