摘要 |
Stretched filaments of aromatic polyesters e.g. polyethylene trephthalate are passed through a bath containing an optical brightener e.g.: <FORM:0969259/D1-D2/1> and a solution, suspension or emulsion of a substance boiling at 120-350 DEG C. e.g. an alcohol, phenol, carboxylic acid or ester, amine, alkyl phosphate hydrocarbon, or vinyl or acrylic polymer. The bath may be at room temperature, and the suspending medium or solvent for the treating compounds may be aqueous or non-aqueous e.g. methanol or ethanol. |