ISO 23900-5:2015

Overview

ISO 23900-5:2015 specifies a laboratory method - the filter pressure value (FPV) test - for assessing the degree of dispersion (dispersibility) of pigments and extenders in thermoplastic polymers. The method is intended for colour concentrates used in extrusion and melt‑spinning processes. FPV is measured as the pressure increase generated at a defined screen‑pack during melt extrusion and provides a quantitative indicator of agglomerates or poorly dispersed particles in a polymer melt.

Keywords: ISO 23900-5, filter pressure value test, dispersibility in plastics, pigments and extenders, colour concentrate testing.

Key topics and technical requirements

• Principle: A test mixture (colour concentrate + basic test polymer) is extruded through a defined screen‑pack; the pressure difference between start and maximum pressure in front of the screen‑pack is used to calculate the FPV.
• Materials:
  • Colour concentrate: homogeneous preparation of a colorant in a thermoplastic polymer.
  • Basic test polymer: agreed grade/type (development work was carried out in polypropylene).
  • Test mixtures:
    • Mixture 1 - 200 g total with 5.0 g colorant (2.5%) for colour pigments.
    • Mixture 2 - 1 000 g total with 80.0 g colorant (8%) for white and carbon black pigments.
• Apparatus:
  • Single‑screw extruder (19–30 mm diameter, L/D 20–30) with non‑grooved barrel and screw without dispersing elements.
  • Melt pump (constant throughput ~50–60 cm3/min) and melt pressure transducers (resolution 0.1 bar). Maintain melt pressure (controller) typically 30–60 bar to ensure pump fill.
  • Screen‑packs as defined filter media (screen diameter ≈ 33.8 mm) with specific multi‑layer constructions; breaker plate to define free area; sealing ring specifications given.
  • Pressure transducer accuracy typically ±1% with repeatability < ±0.1%.
• Procedure essentials:
  • Pre‑heat and purge equipment with test polymer, mount specified screen‑pack and breaker plate, record pressure profile during extrusion.
  • FPV result is equipment‑ and condition‑dependent - direct comparability requires identical preparation and test conditions.
• Reporting and precision: The standard includes requirements for test reporting and notes on precision; results are only comparable when methods and equipment match.

Applications and users

• Quality control laboratories evaluating dispersion quality of colour concentrates.
• Pigment and additive manufacturers for product development and acceptance testing.
• Plastics compounders and processors (extrusion, fiber spinning) for process troubleshooting and supplier qualification.
• R&D teams optimizing formulations to reduce agglomeration and improve color performance.

Practical benefits: objective, reproducible metric (FPV) for dispersibility; aids supplier specifications, batch release, and comparative ranking of concentrates.

Related standards

• ISO 23900 series (Parts 1–6) - broader methods for dispersion and colouristic assessment in plastics.
• ISO 9044 - referenced for screen mesh details.
• EN 10088-1 - referenced for suitable stainless steel types used in screen construction.

Use ISO 23900-5 when you need a standardized, quantitative filter pressure method to assess pigment dispersibility in thermoplastic extrusion and melt‑spinning applications.