Thermoplastic flame retardant resin compositions

1. A thermoplastic flame retardant resin composition comprising:

(A) about 40 to 95 parts by weight of a styrenic resin selected from the group consisting of styrenic resin consisting of styrenic monomeric units without rubber, rubber modified styrenic resin wherein the styrenic portion consists of styrenic monomeric units and a mixture thereof, wherein said rubber modified styrenic resin is produced by polymerizing 80 to 99.5 parts by weight of one or more monomer(s) selected from the group consisting of styrene, N-substituted styrene, and α-alkyl styrene to 0.5 to 20 parts by weight of a rubber selected from the group consisting of butadiene, isoprene, copolymer of butadiene and styrene, and alkyl acrylate;

(B) about 5 to 60 parts by weight of a polyphenylene ether;

(C) about 0.1 to 40 parts by weight of a rubber modified styrenic graft copolymer resin based on 100 parts by weight of the sum of (A) and (B) wherein said rubber modified graft copolymer resin is comprised of about 40 to 65% by weight of a rubber and 60 to 35% by weight of a styrenic copolymer resin which contains about 0.1 to 8% by weight of acrylonitrile or methacrylonitrile and about 92 to 99.9% styrenic monomer excluding rubber; and

(D) about 5 to 30 parts by weight of a phosphorous-containing compound flame retardant wherein the phosphorous-containing compound flame retardant in the thermoplastic flame retardant resin composition consists of an aromatic phosphoric acid ester compound based on 100 parts by weight of the sum of (A) and (B).

2. The thermoplastic flame retardant resin composition as defined in claim 1 , wherein said styrenic resin (A) is polystyrene.

3. The thermoplastic flame retardant resin composition as defined in claim 1 , wherein said styrenic resin (A) is a rubber modified polystyrene resin.

4. The thermoplastic flame retardant resin composition as defined in claim 1 , wherein said styrenic copolymer resin contains about 0.1 to 8% by weight of acrylonitrile excluding rubber.

5. The thermoplastic flame retardant resin composition as defined in claim 1 , wherein said styrenic copolymer resin contains about 0.1 to 8% by weight of methacrylonitrile excluding rubber.

6. The thermoplastic flame retardant resin composition as defined in claim 1 , wherein said styrenic copolymer resin further comprises less than 40 parts by weight of a monomer selected from the group consisting of acrylic acid, methacrylate, maleic anhydride, and N-substituted maleimide, per 100 parts by weight of said rubber modified styrenic resin.

7. The thermoplastic flame retardant resin composition as defined in claim 1 , wherein said styrenic copolymer resin contains 0.1 to 5% by weight of acrylonitrile excluding rubber.

8. The thermoplastic flame retardant resin composition as defined in claim 1 , wherein said styrenic copolymer resin contains 0.1 to 5% by weight of methacrylonitrile excluding rubber.

9. The thermoplastic flame retardant resin composition as defined in claim 1 , wherein the styrenic monomer of (C) is styrene, α-methyl styrene, or p-methyl styrene.

10. The thermoplastic flame retardant resin composition as defined in claim 1 , wherein said styrenic monomer is styrene.

11. The thermoplastic flame retardant resin composition as defined in claim 1 , wherein said aromatic phosphoric acid ester is represented by following formula (I):

wherein R 1 , R 2 and R 3 independently of one another are hydrogen or C 1-4 alkyl; X is a C 6-20 aryl group or alkyl-substituted C 6-20 aryl group that are derivatives from a dialcohol derivative wherein the dialcohol derivative is resorcinol, hydroquinol, bisphenol-A or bisphenol-S; and n is 0˜4.

12. The thermoplastic flame retardant resin composition as defined in claim 1 , further comprising an anti-dripping agent, an impact modifier, an inorganic filler, a heat stabilizer, an anti-oxidants, a light stabilizer, a pigment, and/or dye.

13. A thermoplastic flame retardant resin composition comprising:

(A) about 40 to 95 parts by weight of a styrenic resin selected from the group consisting of polystyrene resin, rubber modified polystyrene resin and a mixture thereof;

(B) about 5 to 60 parts by weight of a polyphenylene ether;

(C) about 0.1 to 40 parts by weight of a rubber modified polystyrene copolymer resin based on 100 parts by weight of the sum of (A) and (B) wherein said rubber modified polystyrene graft copolymer resin is comprised of about 40 to 65% by weight of a rubber and 60 to 35% by weight of a polystyrene copolymer resin which contains about 0.1 to 8% by weight of acrylonitrile and about 92 to 99.9% of styrene excluding rubber; and

(D) about 5 to 30 parts by weight of a phosphorous-containing compound flame retardant wherein the phosphorous containing compound flame retardant in the resin composition consists of an aromatic phosphoric acid ester compound based on 100 parts by weight of the sum of(A) and (B).

14. The thermoplastic flame retardant resin composition as defined in claim 13 , wherein said polystyrene copolymer resin contains 0.1 to 5% by weight of acrylonitrile and about 95 to 99.9% by weight of styrene excluding rubber.

15. A thermoplastic flame retardant resin composition comprising:

(A) about 40 to 95 parts by weight of a styrenic resin which consists of styrenic monomeric units;

(B) about 5 to 60 parts by weight of a polyphenylene ether;

(C) about 0.1 to 40 parts by weight of a rubber modified styrenic graft copolymer resin based on 100 parts by weight of the sum of (A) and (B) wherein said rubber modified graft copolymer resin is comprised of about 40 to 65% by weight of a rubber and 60 to 35% by weight of a styrenic copolymer resin which contains about 0.1 to 8% by weight of acrylonitrile or methacrylonitrile and about 92 to 99.9% styrenic monomer excluding rubber; and

(D) about 5 to 30 parts by weight of a phosphorous-containing compound flame retardant wherein the phosphorous-containing compound flame retardant consists of an aromatic phosphoric acid ester compound based on 100 parts by weight of the sum of (A) and (B).

16. The thermoplastic flame retardant resin composition as defined in claim 15 , wherein said styrenic monomeric units are styrene, N-substituted styrene, or α-alkyl styrene monomeric units.

17. The thermoplastic flame retardant resin composition as defined in claim 15 , wherein said styrenic resin (A) is polystyrene resin.

18. The thermoplastic flame retardant resin composition as defined in claim 15 , wherein said rubber modified graft copolymer resin is comprised of about 40 to 65% by weight of a rubber having an average particle size of from 0.1 to 0.4 μm and 60 to 35% by weight of a styrenic copolymer resin which contains about 0.1 to 8% by weight of acrylonitrile or methacrylonitrile and about 92 to 99.9% of styrenic monomer excluding rubber.