Overview
ISO 6502-2:2018 specifies a laboratory method for determining selected vulcanization characteristics of rubber compounds using an oscillating disc curemeter. The standard defines the measurement principle-embedding a biconical disc in a rubber test piece, oscillating it through a small rotary amplitude, and recording the torque as a function of time to produce a torque‑time (M = f(t)) vulcanization curve. ISO 6502-2 is part of the ISO 6502 series; introductory material on curemeters appears in ISO 6502‑1.
Key topics and technical requirements
- Principle: Shear strain is applied by an oscillating biconical disc; torque required to oscillate the disc reflects rubber stiffness (shear modulus) during cure.
- Apparatus components:
- Biconical disc and shaft manufactured from tool steel, minimum 50 HRC hardness.
- Dies machined from non‑deforming tool steel with specified cavity geometry and grooves to minimize slippage.
- Die closure using a pneumatic cylinder with force 11.0 kN ± 0.5 kN.
- Temperature‑controlled aluminium platens with calibrated sensors.
- Disc oscillation:
- Standard frequency 1.7 Hz ± 0.1 Hz (range 0.05–2 Hz for special purposes).
- Standard angular displacement 1.00° ± 0.02° about central position (total amplitude 2°); other amplitudes allowed for specific tests.
- Torque measurement and recording:
- Torque transducer producing signal proportional to torque.
- Recorder response time ≤ 1 s; accuracy ±1% of torque range.
- Specified torque ranges: 0–2.5 N·m, 0–5 N·m, 0–10 N·m.
- Temperature control:
- Die temperature measurement accuracy ±0.1 °C (100–200 °C).
- Platen control to ±0.3 °C at steady state; die temperature should recover within 3 min after loading.
- Calibration and quality:
- Apparatus calibration per Annex A and ISO 18899 guidance.
- Verification of recorder and torque transducer (electronic checks or simulated torque).
- Results and reporting:
- Extracted parameters include torque values, times to specified cure percentages, scorch time and cure rate index; reporting requirements are specified.
Applications
- Production quality control and acceptance testing of rubber compounds.
- R&D and formulation development to compare cure kinetics and final stiffness.
- Supplier verification, batch-to-batch consistency checks, and troubleshooting vulcanization processes.
- Useful for testing labs, rubber product manufacturers, OEMs, and materials certification bodies needing reproducible curemeter data.
Related standards
Keywords: ISO 6502-2:2018, oscillating disc curemeter, vulcanization characteristics, curemeter testing, rubber testing, torque‑time curve, cure rate index, scorch time, calibration.
Open preview (PDF)Rubber — Measurement of vulcanization characteristics using curemeters — Part 2: Oscillating disc curemeter
