ISO 20028-1:2019

Overview

ISO 20028-1:2019 defines a standardized designation system for thermoplastic polyester (TP) moulding and extrusion materials. It covers polyester homopolymers and copolyesters based on PET, PBT, PCT, PEN, PBN and other TP-types used in powder, granules or pellet form - unmodified or modified with colorants, fillers and additives. The standard provides a structured way to identify materials by chemical type, designatory properties and supplementary information, and is intended as a basis for material specifications (not as a source of engineering or processing data).

Key topics and requirements

• Designation structure: A five–data-block individual-item block (Data blocks 1–5) following an optional identity block. Blocks are separated by commas and form the unambiguous material designation.
• Data block 1 (Polymer ID): Chemical symbol for polyester type (e.g., PET, PBT, PEN, PCT) or copolyester formulations.
• Data block 2 (Fillers / reinforcement / recyclate / flame retardant): Codes for filler/reinforcement type and form, nominal content, flame retardant indication (linked to ISO 1043‑4) and optional recyclate declaration (REC(%)).
• Data block 3 (Application / processing / properties): Intended application or processing method (injection, extrusion, blow moulding, etc.) plus positions for important properties, additives and colour information.
• Data block 4 (Designatory properties): Viscosity number and tensile modulus of elasticity levels used to differentiate TP types.
• Data block 5 (Specification block): For additional, contract-specific requirements needed to turn a designation into a full specification.
• Limitations: ISO 20028‑1 does not supply engineering performance, processing conditions, or guarantee identical performance for similarly designated materials. Test methods and additional property determinations are covered in ISO 20028‑2 (where applicable).
• Exclusions: Not applicable to saturated polyester/ester and polyether/ester thermoplastic elastomers (ISO 20029).

Practical applications and users

ISO 20028‑1 is used to:

• Create clear, consistent material specifications and purchase documents.
• Improve product marking and traceability for moulding and extrusion parts.
• Support material selection for design, prototyping and part manufacturing.
• Communicate filler/reinforcement, flame retardancy and recyclate content in a standard format.

Typical users:

• Polymer suppliers and compounders
• OEMs (automotive, electrical, consumer goods)
• Injection moulding and extrusion processors
• Material engineers, specification writers and procurement teams
• Test laboratories and compliance officers

Related standards

• ISO 1043‑1, ISO 1043‑2, ISO 1043‑4 (symbols and abbreviated terms)
• ISO 1628‑5 (viscosity determination for TP)
• ISO 20028‑2 (test specimen preparation and property determination)
• ISO 20029 (thermoplastic elastomers - excluded scope)

Keywords: ISO 20028-1, thermoplastic polyester, TP moulding and extrusion, PET, PBT, PEN, designation system, viscosity number, tensile modulus, material specification, recyclate, flame retardant.