Overview
ISO/TS 16097:2013 - "Vulcanized crumb rubber - Evaluation procedures" defines standardized physical and chemical test methods, test formulations, equipment and processing methods for evaluating the vulcanization characteristics and mechanical properties of vulcanized crumb rubber. It provides laboratory procedures for sampling, preparing test mixes and measuring key parameters (cure behavior, viscosity, tensile, hardness, tear). This Technical Specification is descriptive and does not set acceptance limits or advise on end‑use suitability.
Key topics and requirements
- Sampling & sample prep: Laboratory sample ~1.5 kg; classification by dimension per CEN/TS 14243:2010.
- Raw-material tests: Particle size distribution, free steel and textile content, acetone extract, ash, carbon black and derived rubber content (R = 100 − (acetone extract + ash + carbon black)).
- Standard test formulation: A benchmark mix is given (e.g., STR 20 natural rubber 100 parts, vulcanized crumb rubber 30 parts, reference carbon black 5 parts, stearic acid 2, zinc oxide 3, sulfur 2.25, TBBS 1 - total 143.25 parts). Use of reference materials is recommended.
- Mixing procedures: Two‑stage mixing - internal mixer for initial mixing, laboratory mill for final mixing. Mill temperatures ~50 °C; specified timing/cutting cycles and conditioning (2–24 h) to ensure reproducible mixes.
- Cure evaluation (curemeter): Methods for both oscillating‑disc and rotorless curemeters. Standard test conditions include die temperature 150 °C, oscillation frequency 1.7 Hz, selectivity to reach ≥75% full‑scale deflection, and recording of torque/time parameters t′(50/90/95/99), ML values.
- Other property tests: Mooney viscosity per ISO 289‑1 (record ML(1’+4’) at 100 °C); tensile stress‑strain (ISO 37) after vulcanization at t′(95); Shore A hardness (ISO 7619‑1); tear strength (ISO 34‑1 method B).
- Reporting: Test report must reference ISO/TS 16097, include sample ID, reference materials, ambient conditions, curemeter type and settings, deviations and all results.
Applications and users
ISO/TS 16097 is aimed at organizations needing a repeatable, comparable evaluation of vulcanized crumb rubber, including:
- Rubber manufacturers and compounders benchmarking crumb rubber performance
- Recycling operations characterizing end‑of‑life tyre derived materials
- Testing laboratories and quality control teams ensuring consistent test data
- Product developers assessing crumb rubber in blends for tires, mats, flooring, or molded goods
- Regulators and procurement teams requiring standardized test data for specifications
Benefits include improved data comparability between labs, better process control during mixing/vulcanization, and a consistent basis for material selection and R&D.
Related standards
Relevant cross‑references cited by ISO/TS 16097: ISO 2393 (mixing/vulcanization), ISO 3417 / ISO 6502 (curemeter methods), ISO 289‑1 (Mooney viscosity), ISO 37 (tensile), ISO 7619‑1 (Shore hardness), ISO 34‑1 (tear) and CEN/TS 14243 (particle sizing/impurities).