Polycarbonate resin composition with high weld line strength

1. A polycarbonate resin composition comprising:

(A) about 30 to about 95 parts by weight of thermoplastic polycarbonate resin;

(B) about 1 to about 50 parts by weight of rubber-modified-vinyl graft copolymer;

(C) about 0 to about 50 parts by weight of vinyl copolymer; and

(D) about 1 to about 50 parts by weight of amorphous thermoplastic polyester copolymer, wherein said amorphous thermoplastic polyester copolymer (D) is a polyethylene terephthalate resin in which about 5 to about 80% by weight of ethylene glycol is replaced with 1,4-cyclohexane dimethanol;

wherein the amounts of (A), (B), (C) and (D) are based on the total weight of the polycarbonate resin composition.

2. The polycarbonate resin composition of claim 1 , wherein said rubber-modified-vinyl graft copolymer (B) is prepared by graft polymerizing:

(B-1) about 5 to about 95% by weight of a monomer mixture which includes:

(B-1.1) about 40 to about 95% by weight of a monomer comprising styrene, α-methyl styrene, halogen or C1-C4 alkyl substituted styrene, C1-C8 alkyl ester of methacrylic acid, C1-C8 alkyl ester of acrylic acid, or a combination thereof; and

(B-1.2) about 5 to about 60% by weight of a monomer comprising acrylonitrile, methacrylonitrile, C1-C8 alkyl ester of methacrylic acid, C1-C8 alkyl ester of acrylic acid, maleic acid anhydride, C1-C4 alkyl or phenyl N-substituted maleimide, or a combination thereof; and

(B-2) about 5 to about 95% by weight of a rubber comprising butadiene rubber, acryl rubber, ethylene-propylene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, isoprene rubber, ethylene-propylene-diene monomer rubber(EPDM), polyorganosiloxane-polyalkyl(meth)acrylate rubber complex, or a combination thereof.

3. The polycarbonate resin composition of claim 1 , wherein said vinyl copolymer (C) is a vinyl copolymer or a combination thereof prepared by copolymerizing:

(C-1) about 30 to about 85% by weight of a monomer comprising styrene, α-methyl styrene, halogen or C1-C4 alkyl substituted styrene, or a combination thereof; and

(C-2) about 15 to about 70% by weight of a monomer comprising acrylonitrile, methacrylonitrile, maleic acid anhydride C1-C4 alkyl or phenyl N-substituted maleimide, or a combination thereof.

4. The polycarbonate resin composition of claim 1 , wherein said polycarbonate resin comprises:

(A) about 40 to about 95 parts by weight of the thermoplastic polycarbonate resin;

(B) about 2 to about 40 parts by weight of the rubber modified-vinyl graft copolymer;

(C) about 1 to about 30 parts by weight of the vinyl copolymer; and

(D) about 3 to about 40 parts by weight of the amorphous thermoplastic polyester copolymer,

wherein the rubber modified-vinyl graft copolymer (B) is prepared by graft polymerizing:

(B-1) about 25 to about 95% by weight of a monomer mixture which includes:

(B-1.1) 40 to about 90% by weight of a monomer comprising styrene, α-methyl styrene, C1-C4 alkyl substituted styrene, or a combination thereof; and

(B-1.2) 10 to about 60% by weight of a monomer comprising acrylonitrile, methacrylonitrile, maleic acid anhydride, C1-C4 alkyl or phenyl N-substituted maleimide, or a combination thereof; and

(B-2) about 5 to about 75% by weight of a rubber comprising butadiene rubber, acryl rubber, styrene-butadiene rubber, polyorganosiloxane-polyalkyl(meth)acrylate rubber complex, or a combination thereof; and

wherein the vinyl copolymer (C) is prepared by copolymerizing:

(C-1) about 30 to about 85% by weight of a monomer comprising styrene, α-methyl styrene, halogen or C1-C4 alkyl substituted styrene or a combination thereof; and

(C-2) about 15 to about 70% by weight of a monomer comprising acrylonitrile, methacrylonitrile, maleic acid anhydride C1-C4 alkyl or phenyl N-substituted maleimide, or a combination thereof.

5. The polycarbonate resin composition of claim 1 , wherein said rubber modified-vinyl graft copolymer (B) is prepared by graft copolymerizing a rubber comprising butadiene rubber, acryl rubber, styrene-butadiene rubber, or a combination thereof, and a monomer comprising styrene, acrylonitrile, (meth)acrylic alkyl ester monomer, or a combination thereof.

6. The polycarbonate resin composition of claim 1 , wherein said vinyl copolymer (C) is prepared by copolymerizing a monomer mixture of styrene and acrylonitrile; a monomer mixture of styrene, acrylonitrile and methacrylic acid methyl ester; a monomer mixture of α-methyl styrene and acrylonitrile; a monomer mixture of α-methyl styrene, acrylonitrile and methacrylic acid methyl ester; a monomer mixture of styrene, αmethyl styrene, and acrylonitrile; a monomer mixture of styrene, α-methyl styrene, acrylonitrile, and methacrylic acid methyl ester; a monomer mixture of methacrylic acid methyl ester and acrylic ester; or a monomer mixture of styrene and maleic acid anhydride.

7. The polycarbonate resin composition of claim 1 , further comprising about 0.1 to about 60 parts by weight based on the about 100 parts by weight of the polycarbonate resin of an additive selected from flame retardants, heat stabilizers, antioxidants, light-stabilizers, fluorescent brightening agents, lubricants, mold lubricants, nucleating agents, antistatic agents, reinforcers, inorganic additives, pigments, dyes, or a combination thereof.

8. A molded article prepared from the polycarbonate resin composition of claim 1 .

9. The polycarbonate resin composition of claim 1 , wherein said amorphous thermoplastic polyester copolymer (D) is a polyethylene terephthalate resin in which about 20 to about 40% by weight of ethylene glycol is replaced with 1,4-cyclohexane dimethanol.