Overview
ISO/TR 16098:2012 - "Reclaimed rubbers and reclaimed crumb rubbers - Evaluation of dispersion in rubber mixes" defines standard materials, formulations, equipment and processing methods for assessing how reclaimed rubber and crumb rubber disperse in rubber compounds. The Technical Report prescribes a white masterbatch formulation, incorporation recipe, mixing and vulcanization procedures, and an optical measurement method (light macroscopy with digital imaging) to quantify particle sizes and surface coverage.
Key topics and requirements
- Standard formulations
- White masterbatch (parts by mass): Natural rubber TSR 3L 100.00; Stearic acid 1.50; Zinc oxide 3.00; TiO2 (anatase) 105.00; Liquid paraffin 15.00 (total 224.50).
- Incorporation formulation: White masterbatch 100.00; Reclaimed/crumb rubber 10.00; Sulfur 2.50; TBBS 1.00 (total 113.50). The 10 part crumb loading is recommended to assess dispersion.
- Mixing and processing
- Internal mixer target: final mix temperature ~120 °C (procedure timings provided).
- Mill mixing and roll settings specified; sheet and condition batches 2–24 h before vulcanization.
- Vulcanize test pieces at 150 °C ± 5 °C for 15 minutes.
- Measurement method (light macroscopy + image analysis)
- Test-piece preparation: razor blade cut using a vertical cut device to produce a flat surface (~8 mm × 10 mm cross-section).
- Apparatus: optical macroscope with numerical camera, strong lamp (indirect lighting, ~60° angle).
- Imaging: magnification x20; recommended ~10 photographs from different zones.
- Image processing: convert to grayscale, enhance contrast, binarize and measure particle metrics.
- Reported metrics: Equivalent Circular Diameter (ECD, Heywood diameter) - particles