Overview
ISO 2475:2011 - Chloroprene rubber (CR) - General-purpose types - Evaluation procedure defines the standard test methods, materials and processing steps for evaluating general-purpose chloroprene rubbers (CR). The standard covers physical and chemical tests on raw CR (Mooney viscosity, volatile matter, ash), standard test formulations for sulfur‑modified and mercaptan‑modified CR, mixing and premastication procedures, miniature internal mixer (MIM) options, and the evaluation of vulcanization characteristics using curemeters and tensile testing of vulcanizates.
Keywords: ISO 2475:2011, chloroprene rubber, CR, evaluation procedure, vulcanization characteristics, Mooney viscosity, curemeter, standard test formulation.
Key topics and technical requirements
- Scope and classes: Applies to general‑purpose CR falling into sulfur‑modified, mercaptan‑modified, or other modified types (other types may follow the sulfur or mercaptan procedure).
- Sampling & sample preparation: Sampling per ISO 1795; typical sample mass ~1.5 kg with specified preparative steps.
- Raw rubber tests:
- Mooney viscosity measured per ISO 289-1 and reported as ML(1+4) at 100 °C.
- Volatile matter per ISO 248‑1 (oven or hot‑mill method; mill roll temp 50 °C ±5 °C).
- Ash per ISO 247.
- Standard test formulations:
- Sulfur‑modified CR: CR 100 parts, stearic acid 0.5, MgO 4.0, Carbon black 25.0, ZnO 5.0 (total 134.5 parts).
- Mercaptan‑modified CR: two formulations (A and B) shown in the standard (e.g., CR 100, MgO 4, Carbon black 25, ZnO 5, with MTT‑80 curative or a sulfur/DOTG/CBS system).
- Mixing & processing: Mill premastication and mixing procedures with roll surface temperature maintained at 50 °C ±5 °C, specified nip settings, sequencing and total mix times; conditioning of mixes 2–24 h before vulcanization.
- Vulcanization & testing: Use of oscillating‑disc or rotorless curemeters (ISO 3417, ISO 6502) to evaluate cure characteristics and tensile testing per ISO 37 for vulcanized properties.
- Safety notes: Advises awareness of potential emissions (e.g., DOTG/o‑toluidine) and substitution of ethylene thiourea by MTT where applicable.
Applications and users
ISO 2475:2011 is intended for:
- Quality control and incoming inspection in CR manufacturing.
- Compound development and R&D in rubber and elastomer labs.
- Rubber testing laboratories and third‑party certification bodies.
- Specification writers, procurement teams and OEMs requiring consistent CR evaluation procedures.
Practical benefits: consistent comparison of vulcanization behavior, reproducible test mixes, and harmonized test reporting for material selection and process control.
Related standards
