ISO 4907-4:2025

Overview

ISO 4907-4:2025 – Plastics - Ion exchange resin - Determination of particle size by laser diffraction method is an international standard published by ISO. This standard specifies the method for determining the particle size distribution of ion exchange resins using the laser diffraction technique, covering a broad range from 0.1 micrometres to 2.0 millimetres. Accurate measurement of particle size is essential for the consistent performance and quality control of ion exchange resins, which are widely used in water treatment, chemical processing, and biochemical applications.

Key Topics

• Test Scope: Defines the particle size range from 0.1 μm to 2.0 mm for ion exchange resins.
• Principle: Utilizes laser diffraction, where a dispersed resin sample is exposed to a laser beam. The scattered light pattern is detected and mathematically analyzed, resulting in a volumetric particle size distribution.
• Apparatus and Materials: Requires a laser diffraction particle size analyser compliant with ISO 13320 and water of grade 3 purity (ISO 3696).
• Sample Preparation: Follows ISO 4907-1 sampling recommendations to ensure results are representative.
• Procedure Highlights:
  • Preparation and alignment of the analyser.
  • Setting key parameters: dispersion medium, analytical model, refractive index, absorptivity, and use of ultrasound for sample dispersion.
  • Conducting multiple tests for result consistency.
• Data Analysis: Calculation of percent below/above specific sizes, effective size (D10), median size (D50), uniformity coefficient, area-weighted mean size, and volume-weighted mean size.
• Repeatability: Specifies relative standard deviations for size parameters, ensuring reliable and precise results.
• Reporting: Outlines required details for comprehensive and transparent test documentation.

Applications

Adherence to ISO 4907-4:2025 ensures reliable and reproducible measurement of particle size distribution in ion exchange resins. The standard is crucial for:

• Manufacturers of ion exchange resins seeking to maintain strict quality control and uniformity in product batches.
• Quality assurance laboratories in the plastics and chemical industries to reliably assess material properties.
• End users in water purification, chemical synthesis, and pharmaceuticals where the particle size of resins directly impacts efficiency and performance.
• Regulatory compliance for organizations requiring standardized reporting for safety, quality, and traceability.

Implementing this standard helps minimize variability, optimize resin function in end-use applications, and supports consistent product performance.

Related Standards

For comprehensive and harmonized testing, ISO 4907-4:2025 references and aligns with several related standards, including:

• ISO 3696: Water for analytical laboratory use - Specification and test methods
• ISO 4907-1: Plastics - Ion exchange resin - Part 1: Determination of exchange capacity of acrylic anion exchange resins
• ISO 9276-2: Representation of results of particle size analysis - Calculation of average particle sizes/diameters and moments
• ISO 13320: Particle size analysis - Laser diffraction methods

Together, these standards create an integrated framework for the accurate measurement, calculation, and reporting of physical and chemical properties of ion exchange resins and related plastic materials.

By following ISO 4907-4, organizations demonstrate their commitment to international best practices in material testing, ensuring product reliability and market acceptance globally.