| abstract |
An improved process for controlling and reducing the concentration of free carboxyl end groups in condensation polyester melt spun fiber is provided. By selection of a multifunctional compound, it is possible to increase the intrinsic viscosity of the fiber. The process comprises admixing and reacting with molten polyester polymer an effective amount of a lactim compound of formula (I), wherein n is an integer of 2 to 15; m is an integer of 1 to 4; R1? and R2? are independently hydrogen, halogen, nitro, amine, C1?-C10? alkyl, C5?-C12? cycloalkyl, C7?-C9? alkyl aromatic, or C6?-C10? aromatic; and R3? is a mono- to tetravalent organic radical selected from the group consisting of C1?-C32? alkyl, C5?-C14? cycloalkyl, C7?-C16? alkyl aromatic, and C6?-C14? aromatic. The lactim reacted polymer is then melt spun to form a fiber. |