This document establishes a system of designation for polybutene-1 (PB-1) thermoplastic materials which can be used as the basis for specifications. For the sake of simplicity@ the designation polybutene-1 and the abbreviation PB are used in this document. The types of polybutene plastics are differentiated from each other by a classification system based on appropriate levels of the designatory property melt volume-flow rate and on information about basic polymer parameters@ intended application and/or method of processing@ important properties@ additives@ colorants@ fillers and reinforcing materials. This document is applicable to all butene-1 homopolymers and to copolymers of butene-1 with a maximum content of other 1-olefinic monomers of less than 50 g/kg (mass fraction) and with a content of non-olefinic monomers with functional groups up to a maximum of 3 g/kg (mass fraction). It applies to materials ready for normal use in the form of powder@ granules or pellets@ unmodified or modified by colorants@ additives@ fillers@ etc. 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 for a particular application and/or method of processing. If such additional properties are required@ they are intended to be determined in accordance with the test methods specified in ISO 21302?2@ if suitable. In order to specify a thermoplastic material for a particular application or to ensure reproducible processing@ additional requirements are given in data block 5 (see 4.1).