Overview
EN ISO 11667:1999 (ISO 11667:1997) specifies laboratory dissolution methods for determining the resin, reinforcement‑fibre and mineral‑filler contents of fibre‑reinforced plastics used in moulding compounds and prepregs. It covers typical materials such as prepregs (yarns, rovings, tapes, fabrics) and moulding compounds (SMC, BMC, DMC). The standard defines two extraction techniques-Method A (Soxhlet extraction) as the reference and Method B (immersion in solvent, beaker) for simpler quality‑assurance testing.
Key topics and technical requirements
- Scope & limitations
- Applicable to prepregs and moulding compounds where the resin is soluble in organic solvents.
- Not applicable when reinforcement is soluble in the solvent or the resin is partly/fully cured and insoluble.
- Two methods
- Method A – Soxhlet extraction: reference method for complete extraction; used when higher accuracy is required.
- Method B – Immersion in beaker: simpler equipment, suited to routine QA.
- Solvents & apparatus
- Examples of suitable solvents: dichloromethane, acetone, methyl ethyl ketone (butan‑2‑one), denatured ethanol. Other solvents may be used as needed.
- Typical apparatus: Soxhlet, ventilated oven (105 °C ±3 °C), desiccator, precision balance (0.5 mg accuracy), sintered‑glass filters (porosity P160) for separation.
- Sampling & specimen preparation
- Test on at least two representative specimens (recommended mass 2–20 g); perform a third if results differ by more than 5 %.
- Special handling for materials with volatile monomer or solvents (sealed sampling, limit on exposure time).
- Separation & calculation
- Resin content determined from mass loss after solvent extraction (resin + sizing/volatile content included).
- Where mineral fillers are present, fibres and fillers are separated either by acid dissolution (HCl) or by filtration, and contents are calculated from successive mass measurements.
- Quality control
- Results are brought to constant mass by repeated drying/weighing; Method A is the dispute‑resolution reference.
Applications and users
- Who uses it:
- Composite materials laboratories, incoming inspection and QA teams at composite manufacturers (SMC, BMC, DMC, prepreg makers), third‑party test labs, R&D and failure‑analysis teams.
- Typical uses:
- Verifying resin content and fibre/filler ratios for process control, specification compliance, material certification, and complaint investigations.
- Establishing baseline material data for product development and comparing batches.
Related standards
- ISO 1172 (Textile‑glass‑reinforced plastics - calcination methods) is recommended where resin is cured and dissolution is not suitable.
- Normative references within ISO 11667 include ISO 291 (conditioning atmospheres), ISO 472 (vocabulary) and ISO 4793 (sintered filter porosity).
Keywords: EN ISO 11667, ISO 11667:1997, fibre‑reinforced plastics, moulding compounds, prepregs, resin content determination, dissolution methods, Soxhlet extraction, SMC BMC DMC, mineral filler analysis.