Flame retardant thermoplastic copolymer, method for preparing the same, and molded article including the same

1. A thermoplastic copolymer, which is a polymer of a monomer mixture comprising: a phosphorus (meth)acrylic monomer represented by Formula 1; an aromatic vinyl monomer; and a vinyl cyanide monomer:

wherein R 1 is hydrogen or methyl; R 2 is a substituted or unsubstituted C 1 to C 20 hydrocarbon group; R 3 and R 4 are the same or different and are each independently a substituted or unsubstituted C 6 to C 20 cyclic hydrocarbon group; m is an integer from 1 to 10; and n is an integer from 0 to 5.

2. The thermoplastic copolymer according to claim 1 , wherein the phosphorus (meth)acrylic monomer is present in an amount of about 1 wt % to about 70 wt %, and the monomers comprising the aromatic vinyl monomer and the vinyl cyanide monomer are present in an amount of about 30 wt % to about 99 wt %.

3. The thermoplastic copolymer according to claim 1 , wherein the monomer mixture has a molar ratio of the aromatic vinyl monomer to the vinyl cyanide monomer from about 6:about 4 to about 9:about 1.

4. The thermoplastic copolymer according to claim 1 , wherein the aromatic vinyl monomer comprises styrene, alkyl group-substituted styrene, vinylnaphthalene, α-methylstyrene, β-methylstyrene, alkyl group-substituted α-methylstyrene, tert-butylstyrene, halogenated styrene, alkoxystyrene, acetoxystyrene, hydroxystyrene, α-carboxystyrene, α-alkoxystyrene, or a mixture thereof.

5. The thermoplastic copolymer according to claim 1 , wherein the vinyl cyanide monomer comprises acrylonitrile, methacrylonitrile, ethacrylonitrile, or a mixture thereof.

6. The thermoplastic copolymer according to claim 1 , wherein the thermoplastic copolymer has a weight average molecular weight from about 5,000 g/mol to about 500,000 g/mol.

7. The thermoplastic copolymer according to claim 1 , wherein the thermoplastic copolymer has a flame retardancy level of V2 or higher, as measured on a 3.2 mm thick specimen according to the UL94 vertical flammability test method.

8. The thermoplastic copolymer according to claim 1 , further comprising at least one of a flame retardant, surfactant, nucleating agent, coupling agent, filler, plasticizer, impact modifier, lubricant, antibacterial agent, release agent, heat stabilizer, antioxidant, photostabilizer, compatibilizer, inorganic additive, antistatic agent, pigment, dye or a mixture thereof.

9. A method for preparing a thermoplastic copolymer comprising:

performing polymerization by introducing a polymerization initiator to a monomer mixture comprising a phosphorus (meth)acrylic monomer represented by Formula 1, an aromatic vinyl monomer, and a vinyl cyanide monomer:

wherein R 1 is hydrogen or methyl; R 2 is a substituted or unsubstituted C 1 to C 20 hydrocarbon group; R 3 and R 4 are the same or different and are each independently a substituted or unsubstituted C 6 to C 20 cyclic hydrocarbon group; m is an integer from 1 to 10; and n is an integer from 0 to 5.

10. The method according to claim 9 , wherein the polymerization initiator is a radical polymerization initiator.

11. The method according to claim 9 , wherein polymerization is performed by further introducing at least one additive comprising a flame retardant, surfactant, nucleating agent, coupling agent, filler, plasticizer, impact modifier, lubricant, antibacterial agent, release agent, heat stabilizer, antioxidant, photostabilizer, compatibilizer, inorganic additive, antistatic agent, pigment, dye or a mixture thereof to the monomer mixture.

12. A molded article produced from the thermoplastic copolymer according to claim 1 .