ISO 8780-2:1990

Overview

ISO 8780-2:1990 specifies a laboratory method for preparing and assessing pigment and extender dispersions using an oscillatory shaking machine. Intended primarily for quality control, the method uses an agreed low‑viscosity binder system and small mill bases so grinding spheres can move freely. It minimizes solvent loss by testing several small batches simultaneously in a closed holder and is restricted to low‑viscosity mill bases - it is not suitable for optimizing formulations for other dispersing techniques.

Key topics and technical requirements

• Scope: Dispersion preparation for quality control of pigments and extenders; read in conjunction with ISO 8780-1 (Introduction).
• Apparatus: Paint‑conditioning (shaking) machine running at ~680–690 reciprocating strokes/min, 16 mm stroke, ±15° oscillation; a multi‑position holder; matching containers and grinding spheres.
• Containers & volumes: Containers must be identical and agreed between parties; mill base should occupy ~30% of container volume.
• Grinding spheres: Use same type, mean diameter and density for all samples in a series. Example: glass spheres ~3.0 mm ±0.5 mm, density ~2.6 g/cm3 ±0.2 g/cm3. Apparent sphere volume ~50% of container.
• Mill base composition: Binder system (binder + solvent + concentration) is agreed and recorded; viscosity must permit free movement of spheres. Example pigment concentrations (starting points):
  • Low binder demand: >40% (m/m)
  • Medium binder demand: 10–40% (m/m)
  • High binder demand: <10% (m/m)
• Procedure: Prepare mill bases, clamp holder in machine, take test portions after agreed shaking times (examples: for hard‑to‑disperse pigments 5, 10, 20, 40, 80, 160 min; for easy‑to‑disperse 1, 2, 4, 8, 16, 32 min). Include de‑aeration and stabilization steps if needed.
• Reporting: Identify product, reference ISO 8780-2, supply supplementary information (Annex A), note deviations and test dates.

Applications and users

• Practical for quality control laboratories in pigment, paint and varnish manufacturing.
• Useful to production, QC chemists, and R&D teams needing repeatable small‑batch dispersion assessments.
• Employed when comparing batches, monitoring dispersion characteristics (fineness, tinting strength, gloss changes in conjunction with ISO 8781 series), and validating consistency of mill bases and processes.

Related standards

• ISO 8780-1:1990 (Introduction) and other parts of ISO 8780 (Parts 3–6) covering alternative dispersion methods (impeller mill, bead mill, automatic muller, triple‑roll mill).
• ISO 8781 series for assessment methods (fineness, tinting strength, gloss).
• Annex A of ISO 8780-2 lists required supplementary information (machine, holder, container, spheres, binder, mill base composition, shaking times, stabilization/de‑aeration procedures).

Keywords: ISO 8780-2:1990, pigments, extenders, dispersion, oscillatory shaking machine, mill base, grinding spheres, binder system, quality control.