Overview
EN ISO 787-8:2000 defines the standardized method for determining the percentage by mass of matter soluble in water in pigments and extenders using a cold extraction process. Developed by ISO in collaboration with CEN, this method ensures consistent and reliable assessment of water-soluble components in solid pigment or extender samples at room temperature. It is part of the broader ISO 787 series focusing on generalized testing methods for pigments and extenders.
This standard is essential for manufacturers, quality control laboratories, and regulatory bodies involved with paints, varnishes, and related raw materials to precisely quantify water-soluble matter in pigment or extender samples without the influence of heat.
Key Topics
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Scope and Purpose
Specifies a cold extraction procedure to determine the water-soluble fraction of pigments and extenders expressed as a percentage by mass.
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Test Methodology
- Sample preparation by weighing an appropriate mass (2g – 20g) representative of the pigment/extender.
- Cold extraction by dispersion in freshly double-distilled or de-ionized water at room temperature.
- Use of membrane filtration or centrifugation to separate soluble matter.
- Drying and weighing the residue to calculate the soluble content.
- Repeated measurements for accuracy.
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Reagents and Equipment
- Water of pH 6 to 7, distillation or de-ionization recommended.
- One-mark volumetric flasks (250 ml capacity).
- Membrane filters or centrifuge.
- Evaporating dishes and oven (maintained at 105 ± 2 °C).
- Analytical balance with at least 1 mg precision.
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Calculation and Reporting
Provides formulas to calculate water-soluble matter percentage and requirements for reproducibility/repeatability with clear guidelines for reporting test results and deviations.
Applications
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Quality Control in Pigment Production
Enables producers to monitor water-soluble impurities affecting product performance and consistency.
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Paints and Varnishes Industry
Assists in raw material testing to ensure compliance with product specifications and performance standards.
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Research and Development
Facilitates analysis of pigment/extender properties under standardized conditions, useful for formulation optimizations.
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Regulatory Compliance
Aligns with international testing protocols ensuring product evaluation is recognized globally, supporting cross-border trade.
Related Standards
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ISO 787 Series
- Part 3: Hot extraction method for matter soluble in water
- Part 4: Determination of acidity or alkalinity of aqueous extract
- Part 5: Oil absorption value
- Part 9: pH value of aqueous suspension
- Part 13: Determination of water-soluble sulfates, chlorides, nitrates
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ISO 1042:1998
Laboratory glassware – Specifications for one-mark volumetric flasks.
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ISO 15528:2000
Protocols for sampling paints, varnishes, and raw materials.
This standard requires explicit declaration of the extraction method used due to differing results between cold and hot water extractions, ensuring clarity in specifications and test reports.
Implementing EN ISO 787-8:2000 supports accurate, reproducible, and internationally accepted testing of water-soluble substances in pigments and extenders, crucial for maintaining product quality and compliance in the coatings and chemical industries.
