ISO 20568-2:2017 PDF

Overview

ISO 20568-2:2017 - Plastics - Fluoropolymer dispersions and moulding and extrusion materials - Part 2: Preparation of test specimens and determination of properties - defines procedures for preparing test specimens and measuring key properties of thermoplastic fluoropolymer resins. Results obtained under this standard can be used for material designation, writing material specifications, quality control and comparison between grades or suppliers.

The standard covers both granular and dispersion-derived PTFE and melt-processable fluoropolymers (e.g., PVDF, FEP, PFA, ETFE and others), and references established test methods and conditioning practices.

Key topics and technical requirements

• Preparation of test specimens
  • Follow applicable ISO specimen-preparation standards; some fluoropolymer-specific procedures are provided.
• Conditioning and test environment
  • Conditioning per ISO 291 (standard atmospheres); specific gravity testing at 23 °C ± 2 °C. PTFE requires careful temperature control (avoid below 22 °C) due to a room-temperature crystalline transition.
• PTFE testing (detailed)
  • Standard specific gravity (SSG): preforming, sintering schedule, oven/rack recommendations and weighing procedures.
  • Bulk density: apparatus (funnel, feeder, volumetric cup, leveller), filling and levelling procedure, and calculation of bulk density to evaluate handling and feeding performance.
  • Particle size and distribution and dispersion-related test-sample prep are also addressed.
  • Safety note: PTFE can evolve harmful gases above ~260 °C - exhaust ventilation required.
• Melt-processable fluoropolymers
  • Determination of melting-peak temperature (DSC) and melt mass-flow rate (MFR/MVR) referencing ISO 1133-1 and ISO 11357 series.
  • Tests for other polymer-specific properties (e.g., glass transition temperature, zero-strength time for some grades) are included.
• Referenced normative standards
  • ISO 291, ISO 472, ISO 565, ISO 1133-1, ISO 11357-2/3, plus related ASTM standards (e.g., ASTM D4894/D4895, ASTM E11).

Practical applications and users

Who benefits:

• Materials and process engineers selecting fluoropolymer grades for moulding/extrusion
• Quality control laboratories verifying batch-to-batch consistency (SSG, bulk density, MFR)
• Product specifiers and purchasers establishing acceptance criteria in contracts
• R&D labs comparing thermal and flow behavior (DSC, MFR) during formulation or compounding

Typical uses:

• Grade designation and material specification development
• Incoming raw-material inspection and supplier qualification
• Troubleshooting processing problems (flow, feed, sintering)
• Regulatory and safety documentation where standard test evidence is required

Related standards

Relevant references cited in ISO 20568-2:2017 include ISO 291, ISO 472, ISO 1133-1, ISO 11357-2/3, ISO 565, and ASTM standards such as ASTM D4894/D4895 and ASTM E11. These should be consulted for full test details and harmonized methods.