ISO 11667:1997

Overview

ISO 11667:1997 specifies laboratory dissolution methods to determine the resin, reinforcement‑fibre and mineral‑filler contents of fibre‑reinforced plastics used as moulding compounds and prepregs. It defines two solvent‑extraction procedures - Method A (Soxhlet extraction) as the reference technique and Method B (immersion in a beaker) for simpler, routine quality‑assurance testing. The standard applies to prepregs (yarns, rovings, tapes, fabrics) and to SMC, BMC and DMC moulding compounds.

Key topics and requirements

• Two extraction methods
  • Method A - Soxhlet extraction: reference method for disputes; uses a Soxhlet apparatus to ensure complete resin removal.
  • Method B - Beaker immersion: simpler equipment for routine QA; may include ultrasonic assistance.
• Solvents: Examples suitable for common resins include dichloromethane, acetone, methyl ethyl ketone (MEK) and denatured ethanol; selection must ensure complete resin extraction.
• Specimen preparation & sampling: Test on two (or more) representative specimens; specimen masses typically 2–20 g; prepregs sampled ≥50 mm from fabric edges.
• Drying and weighing: Dry to constant mass (oven ~105 °C) and use a precise balance (accuracy ~0.5 mg) - repeat drying/weighing until mass change