Thermoplastic resin composition

1. A thermoplastic resin composition comprising: (A) about 10% to about 99% by weight of a thermoplastic resin comprising a rubber-modified acrylic graft copolymer, and (B) about 1% to about 90% by weight of a branched aromatic vinyl copolymer resin comprising a silicon compound, wherein the branched aromatic vinyl copolymer resin (B) comprises a copolymer or a mixture of copolymers formed of (b1) about 10% to about 85% by weight of an aromatic vinyl monomer, (b2) about 10% to about 85% by weight of an unsaturated nitrile monomer, (b3) about 1% to about 50% by weight of a (meth)acrylate monomer, and (b4) about 0.1% to about 20% by weight of a silicon compound having two or more unsaturated groups, wherein the silicon compound (b4) has a vinyl content of about 0.05 to about 10 mmol/g and a viscosity of about 5,000 cPs or less.

2. The thermoplastic resin composition of claim 1 , wherein the branched aromatic vinyl copolymer resin (B) has a weight average molecular weight of about 5,000 to about 5,000,000 g/mol.

3. The thermoplastic resin composition of claim 1 , wherein the aromatic vinyl monomer (b1) is styrene, p-methylstyrene, α-methylstyrene, halogen-substituted styrene, alkyl-substituted styrene, or a mixture thereof.

4. The thermoplastic resin composition of claim 1 , wherein the unsaturated nitrile monomer (b2) is acrylonitrile, methacrylonitrile, ethacrylonitrile, phenylacrylonitrile, α-chloroacrylonitrile, or a mixture thereof.

5. The thermoplastic resin composition of claim 1 , wherein the (meth)acrylate monomer (b3) is an aromatic (meth)acrylate, an aliphatic (meth)acrylate or a mixture thereof having a structure represented by Formula 1, Formula 2, or a mixture thereof:

where m is an integer from 0 to 20, X is hydrogen or methyl, and Y is methyl, cyclohexyl, phenyl, benzyl, methylphenyl, methylethylphenyl, methoxyphenyl, cyclohexylphenyl, chlorophenyl, bromophenyl, phenylphenyl or benzylphenyl;

where m is an integer from 0 to 20, X is hydrogen or methyl, Z is oxygen (O) or sulfur (S), and Ar is phenyl, methylphenyl, methylethylphenyl, methoxyphenyl, cyclohexylphenyl, chlorophenyl, bromophenyl, phenylphenyl or benzylphenyl.

6. The thermoplastic resin composition of claim 5 , wherein the aromatic (meth)acrylate, aliphatic (meth)acrylate or mixture thereof is methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl methacrylate, phenoxy (meth)acrylate, phenoxyethyl (meth)acrylate, 2-ethylphenoxy (meth)acrylate, 2-ethylthiophenyl (meth)acrylate, 2-ethylaminophenyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, 2-phenylethyl (meth)acrylate, 3-phenylpropyl (meth)acrylate, 4-phenylbutyl (meth)acrylate, 2-2-methylphenylethyl (meth)acrylate, 2-3-methylphenylethyl (meth)acrylate, 2-4-methylphenylethyl (meth)acrylate, 2-(4-propylphenyl)ethyl (meth)acrylate, 2-(4-(1-methylethyl)phenyl)ethyl (meth)acrylate, 2-(4-methoxyphenyl)ethyl (meth)acrylate, 2-(4-cyclohexylphenyl)ethyl (meth)acrylate, 2-(2-chlorophenyl)ethyl (meth)acrylate, 2-(3-chlorophenyl)ethyl (meth)acrylate, 2-(4-chlorophenyl)ethyl (meth)acrylate, 2-(4-bromophenyl)ethyl (meth)acrylate, 2-(3-phenylphenyl)ethyl (meth)acrylate, 2-(4-benzylphenyl)ethyl (meth)acrylate, or a mixture thereof.

7. The thermoplastic resin composition of claim 1 , wherein the silicon compound (b4) is at least one silicon compound having a structure represented by

where l, m and n are each independently integers from 0 to 100, with the proviso that l, m and n are not simultaneously zero, and R 1 to R 8 are each independently hydrogen, straight chain or branched C1-C5 alkyl, C4-C6 cycloalkyl, C2-C12 unsaturated alkyl, C6-C10 aryl, hydroxyl, C1-C5 alkoxy, acetoxy, amino, amide, epoxy, carboxyl, halo, ester, isocyanate or mercapto, or R 1 and R 8 are bonded together to provide a cyclic structure, with the proviso that at least two of R 1 to R 8 comprise a polymerizable unsaturated group.

8. The thermoplastic resin composition of claim 7 , wherein the silicon compound (b4) is 2,4,6,8-tetramethyltetravinylcyclotetrasiloxane, 1,3,5-trivinyl-1,1,3,5,5-pentamethyltrisiloxane, 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane, 1,3,5-trivinyl-1,3,5-trimethylcyclosilazane, α,ω-divinylpolydimethylsiloxane, polyvinylmethylsiloxane, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, or a mixture thereof.

9. The thermoplastic resin composition of claim 1 , wherein the thermoplastic resin (A) further comprises an aromatic vinyl copolymer resin.

10. The thermoplastic resin composition of claim 9 , wherein the aromatic vinyl copolymer resin is produced by copolymerizing of about 50% to about 95% by weight of an aromatic vinyl compound with about 5% to about 50% by weight of at least one compound selected from the group consisting of unsaturated nitrile compounds, alkyl (meth)acrylates, maleic anhydride and maleimide compounds.

11. The thermoplastic resin composition of claim 9 , wherein the thermoplastic resin (A) comprises about 30% to about 55% by weight of the rubber-modified acrylic graft copolymer and about 45% to about 70% by weight of the aromatic vinyl copolymer resin.

12. The thermoplastic resin composition of claim 9 , wherein the aromatic vinyl copolymer resin has a weight average molecular weight of about 15,000 to about 250,000 g/mol.

13. The thermoplastic resin composition of claim 1 , wherein the resin composition has an impact strength (⅛″ thick specimen) of about 7.3 to about 30 kgf·cm/cm, as measured using the ASTM D256 procedure, and a flow index (220° C., 10 kg) of about 10 to about 50 g/10 min, as measured using the ASTM D1238 procedure.

14. The thermoplastic resin composition of claim 1 , further comprising at least one additive selected from the group consisting of surfactants, nucleating agents, coupling agents, fillers, plasticizers, impact modifiers, lubricants, antibacterial agents, release agents, heat stabilizers, antioxidants, light stabilizers, compatibilizers, inorganic additives, colorants, antistatic agents, pigments, dyes, flame-proofing agents, and mixtures thereof.

15. A molded article produced from the thermoplastic resin composition of claim 1 .