Overview
EN ISO 584:1997 (ISO 584:1982) specifies a conventional laboratory method for determining the reactivity of unsaturated polyester resins. Reactivity is measured by heating a resin–catalyst mixture in a thermostatted water bath at 80 °C and recording (a) the maximum temperature reached and (b) the time for the temperature to rise from 65 °C to the maximum (or to 90 °C if the maximum exceeds 90 °C). The standard defines detailed test conditions because results are highly sensitive to test geometry, temperature control and instrumentation.
Key topics and requirements
- Test principle: mix resin with catalyst and monitor temperature rise vs time in a controlled 80 °C bath to characterize polymerization rate.
- Catalyst: benzoyl peroxide (or a 50% w/w benzoyl peroxide in dibutyl phthalate mixture as supplied); safety warning about handling pure benzoyl peroxide is included.
- Test portion and proportions: typical mix described as 100 parts resin with 1 part catalyst (procedure uses 2.00 ± 0.01 g of catalyst mixture with 100 ± 1 g resin).
- Apparatus and dimensions:
- Water bath maintained at 80 ± 0.5 °C with stirring and circulation.
- Test-tube: borosilicate glass, internal diameter 18 ± 1 mm, length 210 ± 5 mm, wall thickness 1 ± 0.2 mm.
- Thermocouple: iron-constantan recommended, wire diameter 1 ± 0.05 mm, welded junction ≤ 2 mm, capable of recording to 250 °C; screened thermocouples preferred.
- Optional recorder to log temperature vs time.
- Measurement endpoints:
- Maximum temperature reached.
- Time from 65 °C to maximum (or 65 → 90 °C when applicable).
- Repeatability and acceptance: repeat tests until two consecutive determinations agree within ±5 °C for temperature and ±10% for time.
- Reporting: include identification of resin, thermocouple type, individual and average values, any deviations from specified conditions, and recorded graphs if used.
Applications
- Quality control and batch comparison of unsaturated polyester resins.
- Formulation and R&D to evaluate cure rate changes when modifying resin or catalyst systems.
- Comparative screening of resin suppliers or catalyst variants under standardized conditions.
- Process development where relative reactivity influences mold cycle times, heat management and safety.
Who uses this standard
- Polymer chemists and formulation scientists
- Quality assurance and laboratory technicians in composites and thermoset manufacturing
- R&D labs developing unsaturated polyester resin systems
- Suppliers and purchasers performing comparative acceptance testing
Related standards
- EN/ISO standards and CEN documents addressing plastics testing, thermosetting materials and catalyst specifications are complementary to EN ISO 584 for comprehensive resin evaluation.
