ISO 11908:1996

Overview

ISO 11908:1996 specifies general methods of test for amino resins and solutions of amino resins intended as binders for paints, varnishes and related products. The standard defines an amino resin (condensation products of melamine or urea derivatives with formaldehyde, often etherified) and sets out which properties are to be measured and the standardized test methods to be used. Annex A is normative and provides a turbidity-titration method for assessing compatibility with hydrocarbons.

Key topics and requirements

• Scope: General test methods for amino resins and their solutions used as paint and varnish binders.
• Definition: Amino resin = condensation product of melamine or urea (or derivatives) with formaldehyde.
• Properties and corresponding test methods (as listed in Table 1):
  • Colour - ISO 6271 (platinum‑cobalt scale) or ISO 4630 (Gardner colour scale)
  • Viscosity - ISO 3219 (rotational viscometer)
  • Non‑volatile matter (for resin solutions) - ISO 3251
  • Flashpoint - ISO 1523 or ISO 3679
  • Density - ISO 2811
  • Free‑formaldehyde content - ISO 9020 (sodium sulfite titrimetric method)
  • Acid value - ISO 3682
• Annex A - Compatibility with hydrocarbons (turbidity titration):
  • Test performed at 20–25 °C by titrating a resin solution with a heptane/toluene (80/20 v/v) mixture until a faint bluish haze appears.
  • Procedure notes: sample ≈2 g in a 50 ml conical flask; record volume V of hydrocarbon mixture; compute compatibility characteristic C as C = V / m (ml per gram).
  • Precision: repeatability 5%, reproducibility 10%.
• Sampling reference: ISO 842.

Applications and users

ISO 11908 is used by:

• Binder and resin manufacturers for production quality control and product specifications.
• Paint, varnish and coatings formulators to select and verify binder performance (viscosity, compatibility, non‑volatile content).
• Quality assurance and testing laboratories performing standardized physical and chemical tests (colour, flashpoint, free‑formaldehyde).
• Regulatory and procurement teams who require objective test results for compliance and material acceptance.

Practical uses include routine QC testing, incoming raw‑material verification, formulation troubleshooting (e.g., hydrocarbon compatibility), and safety-related checks (flashpoint, free formaldehyde).

Related standards

Normative references included in ISO 11908:1996 (examples):

• ISO 6271, ISO 4630 - Colour assessment
• ISO 3219 - Viscosity
• ISO 3251 - Non‑volatile matter
• ISO 1523, ISO 3679 - Flashpoint methods
• ISO 2811 - Density
• ISO 9020 - Free‑formaldehyde determination
• ISO 3682 - Acid value
• ISO 842 - Sampling

Keywords: ISO 11908, amino resins, binders for paints, test methods, turbidity titration, compatibility with hydrocarbons, free‑formaldehyde, viscosity, non‑volatile matter, flashpoint.