Flame-retardant polyamide resin composition and molded article

1. A flame-retardant polyamide resin composition comprising, 15 to 78% by weight of a polyamide resin (A), 2 to 20% by weight of a phosphorus-containing flame retarder (B), and 20 to 65% by weight of glass fiber having a non-circular cross-section (C).

2. The flame-retardant polyamide resin composition according to claim 1 , wherein the glass fiber having a non-circular cross-section (C) has an outer circumferential length of 1.05 to 1.8 times longer than an outer circumferential length of glass fiber having a circular cross-section having equal area as the non-circular cross-section.

3. The flame-retardant polyamide resin composition according to claim 1 , wherein the polyamide resin (A) is at least one species selected from xylylene diamine-base polyamide resin, polyamide 66 and polyamide 6, the xylylene diamine-base polyamide resin being obtained by polycondensation reaction of xylylene diamine and α,ω-straight-chain aliphatic dibasic acid, the xylylene diamine being composed of 55 to 100 mole % of meta-xylylene diamine and 45 to 0 mole % of para-xylylene diamine.

4. The flame-retardant polyamide resin composition according to claim 1 , wherein the polyamide resin (A) is a mixture of xylylene diamine-base polyamide resin and at least one species of polyamide 66 and polyamide 6, the xylylene diamine-base polyamide resin being obtained by polycondensation reaction of xylylene diamine and α,ω-straight-chain aliphatic dibasic acid, the xylylene diamine being composed of 55 to 100 mole % of meta-xylylene diamine and 45 to 0 mole % of para-xylylene diamine.

5. The flame-retardant polyamide resin composition according to claim 1 , wherein the polyamide resin (A) comprises 50% by weight or above of xylylene diamine-base polyamide resin obtained by polycondensation reaction of xylylene diamine and α,ω-straight-chain aliphatic dibasic acid, the xylylene diamine being composed of 55 to 100 mole % of meta-xylylene diamine and 45 to 0 mole % of para-xylylene diamine.

6. The flame-retardant polyamide resin composition according to claim 1 , wherein the phosphorus-containing flame retarder (B) contains at least one species selected from reaction product of melamine with phosphoric acid (a), (di)phosphinate salt (b) and phosphazene compound (c).

7. The flame-retardant polyamide resin composition according to claim 1 , wherein the phosphorus-containing flame retarder (B) is a phosphazene compound (c).

8. The flame-retardant polyamide resin composition according to claim 1 , wherein the phosphorus-containing flame retarder (B) is a mixture of reaction product of melamine with phosphoric acid (a) and (di)phosphinate salt (b).

9. The flame-retardant polyamide resin composition according to claim 1 , wherein the phosphorus-containing flame retarder (B) is a mixture of reaction product of melamine with phosphoric acid (a) and (di)phosphinate salt (b), wherein the mixture ratio of (a)/(b) is 40/60 to 60/40.

10. The flame-retardant polyamide resin composition according to claim 1 , further comprising 0.5 to 12% by weight of a metal borate in the composition.

11. The flame-retardant polyamide resin composition according to claim 1 , further comprising 0.5 to 5% by weight of a poly(phenylene ether)-base resin, or a mixed resin of poly(phenylene ether)-base resin and styrene-base polymer in the composition.

12. The flame-retardant polyamide resin composition according to claim 1 , in which the content for the glass fiber having a non-circular cross-section (C) is 30 to 60% by weight.

13. The flame-retardant polyamide resin composition according to claim 1 , wherein the glass fiber having a non-circular cross-section (C) has a cross-sectional area of 2×10 −5 to 8 ×10 −3 mm 2 .

14. The flame-retardant polyamide resin composition according to claim 1 , further comprising a nucleating agent.

15. The flame-retardant polyamide resin composition according to claim 1 , wherein the polyamide resin (A) is at least one species selected from xylylene diamine-base polyamide resin, polyamide 66 and polyamide 6, the xylylene diamine-base polyamide resin being obtained by polycondensation reaction of xylylene diamine and α,ω-straight-chain aliphatic dibasic acid, the xylylene diamine being composed of 55 to 100 mole % of meta-xylylene diamine and 45 to 0 mole % of para-xylylene diamine; and the glass fiber having a non-circular cross-section (C) has an outer circumferential length of 1.05 to 1.8 times longer than an outer circumferential length of glass fiber having a circular cross-section having equal area as the non-circular cross-section.

16. The flame-retardant polyamide resin composition according to claim 15 , wherein the phosphorus-containing flame retarder (B) is at least one species selected from reaction product of melamine with phosphoric acid (a), (di)phosphinate salt (b) and phosphazene compound (c).

17. The flame-retardant polyamide resin composition according to claim 15 , further comprising 0.5 to 12% by weight of a metal borate in the composition.

18. The flame-retardant polyamide resin composition according to claim 15 , further comprising 0.5 to 5% by weight of a poly(phenylene ether)-base resin, or a mixed resin of poly(phenylene ether)-base resin and styrene-base polymer in the composition.

19. The flame-retardant polyamide resin composition according to claim 15 , wherein the phosphorus-containing flame retarder (B) is a mixture of reaction product of melamine with phosphoric acid (a), and (di)phosphinate salt (b), wherein the mixture ratio of (a)/(b) is 40/60 to 60/40.

20. A molded article obtained by molding a flame-retardant polyamide resin composition comprising 15 to 78% by weight of a polyamide resin (A), 2 to 20% by weight of a phosphorus-containing flame retarder (B), and 20 to 65% by weight of glass fiber having a non-circular cross-section (C).