Overview
EN ISO 23900-4:2018 establishes a standardized method for evaluating the colouristic properties and ease of dispersion of white pigments in polyethylene (PE) using two-roll milling. This European Standard, adopted from ISO 23900-4:2015, is developed by CEN and is especially applicable to industries working with pigments and extenders within polymer materials. The procedure provides an objective assessment to compare the performance of white pigments, particularly their tinting strength and dispersibility, under defined processing conditions. The method is recognized throughout the plastics and pigments industries as an essential tool for quality assurance and product development.
Key Topics
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Assessment of Colouristic Properties
The standard outlines how to measure the tinting strength of a white pigment in a PE matrix relative to a reference standard. This allows manufacturers to verify consistency and performance of pigment batches.
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Evaluation of Ease of Dispersion
Using defined two-roll milling conditions, the method determines how easily a pigment distributes throughout polyethylene. The increase in tinting strength after additional milling is used as a quantitative indicator ("DHPE") of dispersibility.
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Standardized Two-Roll Milling
The procedure details specific equipment requirements, including roll dimensions, speed ratios, and temperature controls, to ensure reproducibility during pigment testing.
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Reporting and Reproducibility
Results must include information on materials, processing conditions, and full photometric data. The standard provides guidance on documenting any deviations from the set test method to maintain transparency and repeatability across laboratories.
Applications
EN ISO 23900-4:2018 is highly relevant for:
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Pigment Manufacturers and Suppliers
Evaluating and benchmarking the quality and suitability of white pigments (e.g., titanium dioxide) for use in polyethylene-based products.
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Polymer Compounders and Plastic Converters
Ensuring pigment disperses adequately within PE during product development or quality control, directly affecting colour consistency, opacity, and surface finish in final products.
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Quality Assurance Laboratories
Providing an objective, repeatable protocol for testing pigment performance in PE matrices and supporting claims regarding product properties.
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Product Development and Technical Service
Comparing new pigment formulations or grades and supporting technical recommendations to customers in plastics manufacturing.
This standardized testing method helps reduce variability rooted in processing and enables informed decisions in pigment selection, contributing to efficient manufacturing and improved product performance.
Related Standards
- EN ISO 23900-1: General introduction to methods of dispersion and dispersibility assessment in plastics.
- EN ISO 23900-2: Testing colouristic properties and dispersion of pigments in plasticized PVC by two-roll milling.
- EN ISO 23900-3: Determination of colouristic properties and ease of dispersion of black and coloured pigments in polyethylene.
- EN ISO 23900-5 and EN ISO 23900-6: Alternative methods (filter pressure and film test) for dispersion assessment.
- ISO 787-24: General photometric methods for determining tinting strength and scattering power in pigments and extenders.
- ISO 18314-1: Practical colour measurement in analytical colorimetry.
- ISO 15528: Paint, varnish, and raw material sampling methods.
EN ISO 23900-4:2018 is a cornerstone in pigment and plastics quality assurance, providing a harmonized approach to testing pigment dispersion and colour strength in polyethylene using systematic and industry-accepted procedures.
