Non-halogenated flame retardant polyamide compositions

1. A flame retardant polyamide composition comprising:

polyamides consisting of polyamide 6,6 having a ratio of carboxylic acid end groups to amine end groups of greater than 1.8:1 and a PA-6 homopolymer, wherein the PA-6 homopolymer is present up to 20 wt. %, based on the total weight of the polyamide composition;

a non-halogenated flame retardant;

less than 0.29 wt. % of a first copper-containing heat stabilizer, wherein the first copper-containing heat stabilizer comprises a copper halide and an organohalo-phosphorus compound, based on the total weight of the polyamide composition;

wherein the polyamide composition comprises less than 900 ppm of bromine, and

wherein the polyamide composition retains 50% of its original tensile strength after heat aging for greater than 800 hours when heat aged at a temperature of 195° C. and measured at 23° C.

2. The flame retardant polyamide composition according to claim 1 , wherein the polyamide composition comprises less than 900 ppm of chlorine.

3. The flame retardant polyamide composition according to claim 1 , wherein the polyamide composition comprises less than 1500 ppm of chlorine and bromine in combination.

4. The flame retardant polyamide composition according to claim 1 , further comprising:

a second copper-containing heat stabilizer comprising free copper; and

a copper complexing agent comprising a phosphorus-containing additive.

5. The flame retardant polyamide composition according to claim 4 , wherein the copper complexing agent complexes the free copper of the second copper-containing heat stabilizer.

6. The flame retardant polyamide composition according to claim 4 , wherein the phosphorus-containing additive comprises a phosphine-containing compound, a phosphate-containing compound, a polyphosphate-containing compound, a bromine-containing phosphate, a bromine-containing polyphosphate, a bromine-containing phosphite, a chlorine-containing phosphate, a chlorine-containing polyphosphonate, a chlorine-containing phosphite, triphenylphosphine, triphenylphosphite or combinations thereof.

7. The flame retardant polyamide composition according to claim 4 , wherein the second copper-containing heat stabilizer comprises copper halides, copper acetate, copper propionate, copper benzoate, copper adipate, copper terephthalate, copper isophthalate, copper salicylate, copper nicotinate, copper stearate, copper complex salts, or combinations thereof.

8. The flame retardant polyamide composition according to claim 4 , wherein the second copper-containing heat stabilizer is present in an amount less than 3 wt. %, based on the total weight of the polyamide composition.

9. The flame retardant polyamide composition according to claim 1 , further comprises an amine-containing heat stabilizer, a phenol-containing heat stabilizer, or combinations thereof.

10. The flame retardant polyamide composition according to claim 1 , wherein the polyamide composition comprises less than 5 wt. % of elemental phosphorus, based on the total weight of the polyamide composition.

11. The flame retardant polyamide composition according to claim 1 , wherein the polyamide composition comprises from 0.1 wt. % to 20 wt. % of PA6, wherein the polyamide composition has a tensile elongation of at least 1.0%, and wherein the polyamide composition has a tensile strength retention of at least 75% when heat aged for 1000 hours at a temperature of 155° C. and measured at 23° C.

12. The flame retardant polyamide composition according to claim 1 comprising:

40 wt. % to 70 wt. % of the polyamide 6,6;

5 wt. % to 25 wt. % of the non-halogen flame retardant;

0 wt. % to 30 wt. % of fiberglass;

0 wt. % to 3 wt. % of carbon black; and

0 wt. % to 5 wt. % of zinc stearate and/or zinc borate.

13. A flame retardant polyamide composition comprising:

polyamides consisting of polyamide 6,6 having a ratio of carboxylic acid end groups to amine end groups of greater than 1.8:1 and a PA-6 homopolymer, wherein the PA-6 homopolymer is present up to 20 wt. %, based on the total weight of the polyamide composition;

a non-halogenated flame retardant comprising an organic phosphorus flame retardant; and

an amine-containing heat stabilizer,

wherein the polyamide composition retains 50% of its original tensile strength after heat aging for greater than 450 hours when heat aged at a temperature of 215° C. and measured at 23° C.

14. The flame retardant polyamide composition according to claim 13 , wherein the polyamide composition has a tensile elongation of at least 3.0%.

15. The flame retardant polyamide composition according to claim 13 , wherein the amine-containing heat stabilizer comprise hindered amine-based heat stabilizers.

16. A flame retardant polyamide composition comprising:

polyamides consisting of polyamide having a ratio of carboxylic acid end groups to amine end groups of greater than 1.8:1 and a PA-6 homopolymer, wherein the PA-6 homopolymer is present up to 20 wt. %, based on the total weight of the polyamide composition;

a non-halogenated flame retardant comprising an organic phosphorus flame retardant;

and

a phenol-containing heat stabilizer,

wherein the polyamide composition retains 50% of its original tensile strength after heat aging for greater than 450 hours when heat aged at a temperature of 215° C. and measured at 23° C., and wherein the polyamide composition has a tensile elongation of at least 2.5%.

17. The flame retardant polyamide composition according to claim 16 , wherein the phenol-containing heat stabilizer comprises N, N′-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide)]; pentaerythrityl-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; N,N′-hexamethylenebis(3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide); triethyleneglycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate]; 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1, 1-dimethylethyl}-2,4,8, 10-tetraoxaspiro[5,5]undecane; 3,5-di-tert-butyl-4-hydroxybenzylphosphonate-diethyl ester; 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene; and 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, or combinations thereof.

18. The flame retardant polyamide composition according to claim 16 , wherein the composition further comprises one or more additives comprising a flow modifier, fiberglass, a filler, a synergist, a lubricant/mold-release agent, antioxidants, or combinations thereof.