Overview
EN ISO 23900-5:2018 (ISO 23900-5:2015) defines a laboratory method to assess the degree of dispersion of a colourant (pigment or extender) in a thermoplastic polymer using the filter pressure value (FPV) test. The method is tailored for colour concentrates used in extrusion and melt‑spinning processes and provides a reproducible way to quantify dispersibility under defined equipment and test conditions.
Key topics and technical requirements
- Scope & purpose: Measures dispersibility of colour concentrates in polymers for extrusion/melt‑spinning; results are valid only for the specific equipment, test polymer and conditions used.
- Filter Pressure Value (FPV): Defined as the pressure difference between the start pressure and the maximum pressure recorded in front of a screen pack during extrusion. FPV is the primary metric for dispersion assessment.
- Materials:
- Colour concentrate - homogeneous preparation of pigment/extender in a thermoplastic carrier.
- Basic test polymer - grade/type agreed between parties (development work used polypropylene).
- Test mixture - specified blend of colour concentrate and test polymer.
- Apparatus:
- Single‑screw extruder with a non‑grooved barrel and a screw without dispersing elements.
- Melt pump and melt pressure transducers (one in front of the filter/screen pack).
- Breaker plate and defined screen‑pack configurations.
- Screen‑packs and sealing rings as specified to generate reproducible pressure responses.
- Procedure & evaluation:
- Pre‑conditioning and controlled extrusion of the test mixture.
- Record start pressure and peak pressure; calculate FPV.
- Test repeatability depends on identical sample preparation and equipment setup.
- Limitations:
- The method does not prescribe how colour concentrates are prepared - comparability requires same preparation method.
- Results can vary with different extruder designs, screw geometries or test polymers.
Practical applications
- Quality control of pigment/extender dispersibility in polymer compounds.
- Comparative screening of colour concentrates during R&D and product development.
- Supplier acceptance testing and batch verification for colour concentrates.
- Troubleshooting dispersion issues in extrusion or melt‑spinning operations.
- Process optimization to minimize filter blockages and improve product consistency.
Who should use this standard
- Pigment and extender manufacturers
- Polymer compounders and masterbatch producers
- Extrusion and melt‑spinning equipment manufacturers
- Quality control and R&D laboratories in plastics and textile sectors
Related standards
- Other parts of ISO 23900 series (Parts 1–6) cover general introduction, two‑roll milling methods and film tests.
- EN ISO 23900-5:2018 supersedes EN 13900-5:2005.
Keywords: filter pressure value, FPV, dispersion, pigments, extenders, colour concentrates, thermoplastic polymer, extrusion, melt‑spinning, dispersibility.