Flame resistant semiaromatic polyamide resin composition including zinc stannate, and articles therefrom

1. A flame retardant polyamide resin composition, comprising:

(a) about 30 to about 90 weight percent of a polyamide component comprising about 60 to 100 weight percent of at least one semiaromatic polyamide wherein the semiaromatic polyamide is hexamethylene adipamide/hexamethylene terephthalamide copolyamide (polyamide 6,T/6,6);

(b) at least one flame retardant comprising aluminum diethylphosphinate and/or aluminum methylethylphosphinate;

(c) zinc stannate; and

(d) 0 to about 60 weight percent of at least one inorganic reinforcing agent and/or filler,

wherein the weight percentages of (a) and (d) are based on the total weight of the composition; wherein flame retardant (b) is present in an amount that is about 10 to about 45 percent of the weight of polyamide (a); and wherein zinc stannate (c) is present in an amount that is about 1 to about 50 percent of the weight of flame retardant (b) wherein the composition provides at least 50% less corrosion to a check ring compared to a composition having components (a), (b), and optionally (d), as measured by a Mold Corrosion Test.

2. The composition of claim 1 , wherein the zinc stannate (c) is present in an amount that is about 1.5 to about 40 percent of the weight of flame retardant (b).

3. The composition of claim 1 , wherein the at least one inorganic reinforcing agent and/or filler is present in about 5 to about 60 weight percent, based on the total weight of the composition.

4. The composition of claim 1 , wherein the inorganic reinforcing agent is glass fibers.

5. The composition of claim 1 , wherein the zinc stannate is present in an amount that is about 1.5 to about 40 percent of the weight of the flame retardant.

6. The composition of claim 1 further comprising 0.2 to 4 wt. % of the zinc stannate, based on the total weight of the composition.

7. The composition of claim 1 further comprising 1 to 4 wt. % of the zinc stannate, based on the total weight of the composition.

8. The composition of claim 1 , wherein the zinc stannate is ZnSnO 3 .

9. An article comprising the composition of claim 1 .

10. A method for molding a flame retardant semiaromatic polyamide resin composition, comprising

providing a blended flame retardant semiaromatic polyamide resin composition comprising

(a) a 30 to about 90 weight percent of a polyamide component comprising about 20 to 100 weight percent of at least one semiaromatic polyamide;

(b) at least one flame retardant comprising one or more of a phosphinate of the formula (I); a disphosphinate of the formula (II); and polymers of (I) and/or (II)

wherein R 1 and R 2 are identical or different and are C 1 -C 6 alkyl, linear or branched, and/or aryl; R 3 is C 1 -C 10 -alkylene, linear or branched, C 6 -C 10 -arylene, -alkylarylene or -arylalkylene; M is calcium ions, magnesium ions, aluminum ions and/or zinc ions; m is 2 to 3; n is 1 or 3; and x is 1 or 2;

(c) zinc stannate; and

(d) 0 to about 60 weight percent of at least one inorganic reinforcing agent and/or filler,

wherein the weight percentages of (a) and (d) are based on the total weight of the composition; wherein flame retardant (b) is present in an amount that is about 10 to about 45 percent of the weight of polyamide (a); and wherein zinc stannate (c) is present in an amount that is about 1 to about 50 percent of the weight of flame retardant (b); and

melting and injecting said polyamide resin composition in a molding machine; at a temperature sufficient to provide a flowable melt;

wherein the injecting of the resin composition comprising components (a), (b), (c) and optionally (d) provides at least 50% less corrosion of a check ring than that of injecting a resin composition comprising components (a) (b) and optionally (d); as measured in a Mold Corrosion Test using a molding machine having a nozzle head with said check ring.