Flame Retardant Polyester Composition

A method of reducing the amount of antimony flame retardant compound in a flame retardant composition which comprises combining an alkali metal carbonate with a brominated flame retardant compound in preparing the composition, wherein the composition comprises:

• (a) 40 to 70 percent by weight of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), PBT made from recycled PET, PCT, and glycol modified polycyclohexylenedimethylene terephthalate (PCTG), or a combination thereof;
• (b) 3 to 30 percent by weight of a brominated flame retardant compound;
• (c) 0.5 to 4.5 percent by weight of Sb2O3;
• (d) 0.03 to 0.9 percent by weight of sodium carbonate or potassium carbonate;
• and
• (e) 5 to 45 percent by weight of glass fiber;
• and wherein:
• (i) the composition meets or exceeds the requirements of UL94-V2;
• (ii) less antimony retardant compound is present in the composition comprising (a), (b), (c), and (d) as compared to a composition comprising component (a), (b), (c) and no (d);
• (iii) the comparative tracking index (CTI) for a composition comprising (a), (b), (c), and (d) is the same as or greater than the CTI of a composition comprising component (a), (b), (c) and no (d);
• (iv) the composition does not contain a phosphorous containing flame retardant;
• and wherein the percent by weights are based on the total weight of the composition.