DIN EN ISO 1628-5:2015-05

This standard specifies a method for the determination of the viscosity number (also referred to as "reduced viscosity") of dilute solutions of thermoplastic polyesters (TPs) in certain specified solvents. The method is applicable to poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT), poly- (cyclohexylenedimethylene terephthalate) (PCT), and poly(ethylene naphthalate) (PEN), as well as to copolyesters and other polyesters, defined in ISO 7792-1, that are soluble in one of the specified solvents under the specified conditions. The viscosity number is determined by the general procedure specified in ISO 1628-1, observing the particular conditions specified in this part of ISO 1628. The determination of the viscosity number of a thermoplastic polyester provides a measure of the relative molecular mass of the polymer. The text of ISO 1628-5:1998 has been prepared by Technical Committee ISO/TC 61 "Plastics" of the International Organization for Standardization (ISO) and has been taken over as EN ISO 1628-5:2015 by Technical Committee CEN/TC 249 "Plastics" the secretariat of which is held by NBN (Belgium). The committee responsible for this standard is Working Committee NA 054-02-10 AA "Thermoplast-Formmassen" ("Thermoplastic materials") at DIN Standards Committee Plastics (FNK).