Overview
ISO 20427:2026, published by the International Organization for Standardization (ISO), establishes a standardized procedure for dispersing pigments and extenders prior to sedimentation-based particle sizing. The standard applies specifically to the preparation of samples for particle size analysis, where pigment or extender particles are suspended in a liquid and measured using sedimentation techniques. Correct dispersion is essential for reliable, reproducible particle size distributions, which are critical in applications ranging from paints and coatings to plastics and specialty chemicals.
This document covers the use of ultrasonic devices, shaker devices, and wet jet mills for dispersion, offering optimized methods in alignment with sedimentation-based measurement techniques that rely on the separation of particles by their gravitational or centrifugal response in a contrasting density medium.
Key Topics
-
Dispersion Methods: Detailed procedures for dispersion using ultrasonic probes, bath-type sonicators, shaker-based devices, and wet jet mills. The standard describes best practices for ensuring that agglomerates and aggregates are sufficiently broken down, resulting in well-defined, reproducible primary particles in suspension.
-
Sample Preparation: Guidance on selecting, labeling, and preparing pigment or extender samples. The importance of using high-purity, particle-free reagents and solvents is emphasized to avoid erroneous measurements.
-
Sedimentation-Based Sizing: Explanation of sedimentation-based particle size analysis, including:
- Gravitational methods (Stokesian analysis, X-ray absorption)
- Centrifugal methods (disc and cuvette-type centrifuges)
- Field-flow fractionation
-
These methods rely on differential particle migration in a liquid, necessitating a clear density difference between particles and suspending medium.
-
Apparatus Requirements: Specification of suitable dispersion and measurement equipment, including the minimum performance criteria for sonicators, shaker devices, wet jet mills, balances, and sedimentation instrumentation.
-
Quality and Reproducibility: Recommendations on maintaining consistent test conditions, calibrating energy input, and validating results through data analysis procedures, aligning with related ISO particle size characterization standards.
Applications
ISO 20427:2026 is widely applicable in industries where accurate particle size distribution of pigments and extenders is critical, such as:
- Paints and Coatings: Assures color consistency, opacity, and texture in final products through reliable pigment dispersion and sizing.
- Plastics and Polymers: Enables uniformity in polymer blends and composites, enhancing material properties and processability.
- Ceramics and Construction Materials: Improves quality control by standardizing particle dispersion in materials such as fillers and extenders.
- Research and Quality Laboratories: Facilitates comparative studies, method development, and routine QC of particulate materials.
By standardizing dispersion and measurement procedures, ISO 20427:2026 improves inter-laboratory reproducibility, product performance, and regulatory compliance across the supply chain.
Related Standards
ISO 20427:2026 references and complements several other standards and guidelines:
- ISO 3696: Water for analytical laboratory use
- ISO 9276-1: Graphic representation of particle size analysis results
- ISO 13317 Series: Liquid gravitational sedimentation methods for particle size distribution (Parts 1-5)
- ISO 13318 Series: Centrifugal sedimentation methods (Parts 1-3)
- ISO 18451: Terminology for pigments, dyestuffs, and extenders
- ISO 15528: Sampling procedures for paints, varnishes, and raw materials
- ASTM D5965: Density of coating powders
Together, these standards form a comprehensive foundation for the analytical characterization and quality control of pigments and extenders using sedimentation-based particle size analysis.
Keywords: ISO 20427:2026, pigment dispersion, extender dispersion, sedimentation-based particle sizing, ultrasonic dispersion, shaker device, wet jet mill, particle size analysis, particle size distribution, sample preparation, laboratory standards, analytical methods, quality control.