PHOTOFADING OF FLUORESCENT BRIGHTENING AGENT ON POLY (ETHYLENE TEREPHTHALATE) FILM

Abstract

The photofading behavior of disperse dye type FBA, trans-1, 2-bis (5-methyl-2-benzoxazolyl) ethylene, on PET films dyed under various conditions was kinetically investigated.
The rate of photofading of the FBA on PET films dyed from aqueous ethanol dyebath increased as the rise in their heat setting and/or dyeing temperatures. In the case of PET films dyed from water dyebath, the dye faded more slowly on the films dyed at temperatures below 130°C than on those dyed at temperatures above 130°C.
These results may suggest that the fine structure of PET film changed at about 130°C both in aqueous ethanol and water, and affected the distribution of the FBA molecules on the substrate.
These photofading behavior of the FBA has been provisionally interpreted by the kinetic parameter (α), which is proportional to the ratio between the unimolecular and bimolecular rate constant of the photo-reaction, and by CF curve under different dyeing conditions.