ISO 787-9:2019

Overview

ISO 787-9:2019 outlines a standardized method for determining the pH value of aqueous suspensions of pigments and extenders. This international standard is essential for quality control and product specification in industries dealing with pigments, dyes, and extenders. The document provides clear guidelines on sampling, preparation, and measurement techniques, ensuring consistent and reliable pH testing results across laboratories worldwide.

Maintained by ISO/TC 256, this second edition updates the 1981 version by incorporating modern practices such as the use of methanol as an alternative wetting agent and refining the method for preparing samples and equipment.

Key Topics

• Scope and Purpose
  Establishes a general method to measure the pH of pigment or extender suspensions, crucial for understanding product behavior and compatibility in formulations.

• Sampling Procedures
  Samples must be representative and collected per ISO 15528 to provide accurate and reliable pH measurements reflective of the bulk product.

• Sample Preparation
  Suspensions are prepared at 5% to 10% mass fraction in distilled or demineralized water or an optional buffer solution, maintaining consistency in testing conditions.

• Apparatus Requirements
  Use chemically resistant glass containers fitted with appropriate stoppers and a calibrated pH measuring device with at least 0.1 pH unit sensitivity.

• Measurement Protocol
  The pH of the suspension is recorded after vigorous mixing and a rest period, with temperature control ensuring accuracy. Wetting agents like ethanol or methanol may be added to aid dispersion when necessary.

• Reporting Guidelines
  The final test report must detail the product identification, testing method reference, wetting agents used, results, testing temperature, and any procedural deviations.

Applications

ISO 787-9:2019 is widely applicable across multiple industries, including:

• Paints and Coatings
  Ensuring pigment compatibility and stability by monitoring pH in pigment suspensions helps optimize paint formulations.

• Plastics and Polymers
  The pH of extender suspensions affects processing and product performance, making this test vital during raw material quality control.

• Inks and Printing
  Controlling pigment suspension pH impacts ink stability, drying times, and final print quality.

• Textiles and Dyes
  Accurate pH evaluation of pigment or dye suspensions ensures consistent color application and fabric treatment.

• Laboratories and Quality Control
  Standardized pH testing per ISO 787-9 supports regulatory compliance, laboratory accreditation, and cross-industry product standardization.

Related Standards

• ISO 15528 - Sampling of Paints, Varnishes and Raw Materials
  Defines proper sampling techniques to obtain representative pigment and extender samples for testing.

• ISO 18451-1 - Terminology of Pigments, Dyestuffs and Extenders
  Provides standardized definitions and terms used throughout ISO 787-9, facilitating clear communication.

• ISO 787 Series - General Methods of Test for Pigments and Extenders
  Includes several parts covering diverse test methods to assess physical and chemical properties essential for pigment analysis.

• ISO/IEC Directives, Part 1 & 2
  Outlines document development procedures and editorial rules followed in the preparation and maintenance of ISO standards.

Implementing ISO 787-9:2019 effectively supports consistent quality control and enhances product reliability across industries reliant on pigments and extenders. By standardizing the measurement of pH in aqueous suspensions, businesses can achieve improved process control, product development, and compliance with international requirements.