ISO 21304-1:2019 establishes a system of designation for thermoplastic PE-UHMW materials, which can be used as the basis for specifications.

For the purposes of this document, PE-UHMW materials are polyethylene materials having a melt mass-flow rate (MFR) of less than 0,1 g/10 min, measured at 190 °C and 21,6 kg load.

NOTE It has been confirmed that the melt volume-flow rate (MVR) is useful for characterizing some PE-UHMW materials (e.g. pipe materials) under the test condition of 230 °C/21,6 kg and bore diameter of die with 3,628 mm (see ISO 21304-2).

The types of PE-UHMW are differentiated from each other by a classification system based on appropriate levels of the designatory properties:

a) viscosity number;

b) elongational stress;

c) Charpy double-notched impact strength;

and on information about the intended application and/or method of processing, important properties, additives, colorants, fillers and reinforcing materials.

This designation system is applicable to all PE-UHMW homopolymers and to ultra-high-molecular-weight copolymers of ethylene having a content of other 1-olefinic monomers of less than 50 % by mass and a content of non-olefinic monomers with functional groups up to a maximum of 3 % by mass. It applies to materials ready for normal use in the form of powder, granules or pellets, unmodified or modified by colorants, fillers and other additives.

It is not intended to imply that materials having the same designation give necessarily the same performance. This document does not provide engineering data, performance data or data on processing conditions which can be required to specify a material. If such additional properties are required, they are intended to be determined in accordance with the test methods specified in ISO 21304-2, if suitable.

In order to specify a thermoplastic PE-UHMW material to meet particular specifications, the requirements are to be given in data block 5 (see 4.1).