Overview
ISO 2007:2018 - "Rubber, unvulcanized - Determination of plasticity - Rapid‑plastimeter method" specifies a standardized, rapid test for measuring the plasticity of raw rubber and unvulcanized compounded rubber. The method produces a plasticity number used for quality control and is applicable when determining the plasticity retention index (PRI) as referenced in ISO 2930. This fifth edition (2018) updates apparatus descriptions, temperature control, test piece dimensions and calibration guidance.
Key topics and requirements
- Principle: A disc-shaped test piece is rapidly compressed to 1.00 mm, pre‑heated for 15 s, then subjected to a constant compressive force of 100 N ± 1 N for 15 s. The final thickness is the measure of plasticity.
- Apparatus (rapid‑plastimeter):
- Parallel‑plate plastimeter with heated, parallel circular platens (selectable small platen diameters: 7.30 mm, 10.00 mm or 14.00 mm) and temperature control.
- Means to move platen within 2 s and apply the specified forces, thickness indicator to 0.01 mm, timing device (±0.2 s).
- Punch for preparing test discs (≈13 mm diameter, 3.4 mm ± 0.2 mm thick).
- Bleached acid‑free tissue or cigarette paper (30 × 45 mm) to place between platens and specimen.
- Test conditions: Default test temperature 100 °C ± 1 °C; samples conditioned at 25 °C ± 5 °C for ≥1 h before testing.
- Calibration and standards: Check loading spring and timing per ISO 18899; use standard butyl, Constant Viscosity natural rubber or NIST standard (test piece NBS‑388) for machine checks.
- Results expression: Median thickness of three test pieces after the 15 s compression, reported in hundredths of a millimetre as the plasticity number.
- Test report: Must include sample identification, preparation details (see ISO 1795), platen size, test temperature, plasticity number and date.
Applications and users
- Practical uses:
- Incoming raw rubber inspection and supplier acceptance testing.
- Internal quality control for rubber compounding and processing.
- R&D and formulation comparison to monitor softening, workability and storage stability.
- Determination of PRI in accelerated aging studies (refer to ISO 2930).
- Who uses it:
- QC technicians and laboratory managers in rubber and tyre manufacturing.
- Materials scientists and formulation chemists.
- Accredited test laboratories and standards compliance teams.
Related standards
- ISO 2930 - Plasticity retention index (PRI)
- ISO 1795 - Sampling and sample preparation for raw rubber
- ISO 18899 - Guide to calibration of test equipment
Keywords: ISO 2007:2018, rapid‑plastimeter, rubber plasticity, plasticity number, unvulcanized rubber, PRI, parallel‑plate plastimeter.