Stabilized polyester fibers and films

The present invention pertains to fibers and films prepared from polyesters of a dicarboxylic acid and a diol selected from 1,3-cyclohexanedimethanol, 1,4-cyclohexane-dimethanol, or 1,3-propanediol. The fibers and films contain an epoxide additive and, optionally, an antioxidant, and show an increased dry heat stability when exposed to elevated temperatures in the presence of air. The fibers and films are particularly useful in applications requiring elevated temperatures. Disclosed are fibers and films prepared from polyesters of a dicarboxylic acid, preferably terephthalic acid, and a diol selected from 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, or 1,3-propanediol. The fibers and films contain a multifunctional epoxide additive and, optionally, an antioxidant, and show an increased dry heat stability when exposed to elevated temperatures in the presence of air while preserving excellent hydrolytic stability. Also disclosed is a process for stabilizing polyester fibers by melt blending a polyester and epoxide additive and melt spinning. The fibers and films are particularly useful in applications requiring elevated temperatures.