Overview
ISO 584:1982 specifies a conventional laboratory method to determine the reactivity of unsaturated polyester resins by measuring the exothermic temperature rise when a resin–catalyst mixture is heated in a thermostatted water bath at 80 °C. The test characterizes reactivity by the maximum temperature (Tmax) reached and the time taken for the mixture to rise from 65 °C to Tmax (and, if Tmax > 90 °C, the time from 65 °C to 90 °C). The standard emphasizes strict control of test conditions because results are highly dependent on apparatus and procedure.
Key topics and requirements
- Test composition: Typical mixing uses 100 parts resin with 1 part active benzoyl peroxide (implemented in practice by adding 2 g of a 50% benzoyl peroxide in dibutyl phthalate mixture to 100 g resin).
- Test environment: Water bath maintained at 80 ± 0.5 °C with circulation and stirring.
- Apparatus: Specified test-tube (borosilicate glass) dimensions (internal diameter 18 ± 1 mm, length 210 ± 5 mm), centrally located thermocouple, iron-constantan thermocouple wires with a small welded junction (≤ 2 mm), balance (0.01 g), and stopwatch or recorder.
- Measured parameters: Maximum temperature (Tmax) and time to rise from 65 °C to Tmax; where Tmax exceeds 90 °C also report time to 90 °C.
- Precision and repeatability: Repeat tests until two consecutive determinations differ by no more than 5 °C in temperature and 10% in time.
- Safety note: Handling pure benzoyl peroxide is hazardous-standard warns to observe appropriate safety precautions.
- Reporting: Include identification of resin, thermocouple type, individual and average Tmax and times, any deviations from the prescribed conditions, and recorded temperature–time traces if used.
Applications and who uses it
- Quality control laboratories in polyester resin manufacturing for lot acceptance and batch comparison.
- R&D and formulation teams evaluating catalyst systems, accelerators, or resin modifications.
- Process engineers in composites, laminating, casting and molding industries who need to predict curing behavior, pot life, and peak exotherm.
- Suppliers and purchasers comparing relative reactivity of similar unsaturated polyester resins under standardized conditions.
Related standards
- ISO 584:1982 replaces earlier ISO Recommendation R 584 (1967). Users commonly pair ISO 584 results with other ISO test methods for mechanical, chemical or curing properties of polyester systems when developing specifications or processing windows.
Keywords: ISO 584, unsaturated polyester resins, reactivity determination, 80 °C test, benzoyl peroxide, Tmax, polymerization rate, water-bath method, thermocouple.
Open preview (PDF)Plastics — Unsaturated polyester resins — Determination of reactivity at 80 degrees C (conventional method)
