ISO 28641:2018

Overview

ISO 28641:2018 - Rubber compounding ingredients - Organic chemicals - General test methods specifies standardized sampling and laboratory test methods for organic chemicals used in rubber compounding (for example accelerators, antidegradants including waxes, and vulcanizing agents, excluding peroxides). The standard defines how to take representative samples, determine general physical and chemical characteristics, and report results to support consistent quality control, specification compliance and material characterization.

Key topics and technical requirements

ISO 28641:2018 organizes general test methods and reporting requirements for organic compounding ingredients. Major technical topics include:

• Sampling: apparatus and sampling procedures to obtain representative test samples.
• Density and relative density: hydrometer and pyknometer methods, result expression and reporting.
• Loss on heating: two methods (A and B), calculation steps, expression of results and precision requirements.
• Sieve residue: procedure, apparatus, calculation and precision.
• pH of water extract: extraction principle, apparatus, measurement and test reporting (with pH‑meter verification/calibration in normative annexes).
• Melting point, temperature of solidification, softening point: multiple methods, procedures, expression of results and stated precision.
• Bulk material density: constant mass and constant volume methods.
• Ash content and refractive index: principles, apparatus, calculation and reporting.
• Documentation and precision: sections on test reports, precision (informative annex), and conversion formulas (informative annex).

Normative and informative annexes include pH‑meter verification and calibration (Annex A/B), precision data (Annex C) and density conversion formulae (Annex D).

Practical applications and typical users

ISO 28641:2018 is intended for:

• Quality control and QC laboratories in rubber additive and chemical manufacturing to verify batch conformity.
• Raw material suppliers and formulators for consistent incoming inspection and supplier declarations.
• R&D and product development teams characterizing new accelerators, antidegradants and vulcanizers.
• Regulatory and procurement professionals who require harmonized test evidence for specifications and acceptance criteria. Practical uses include routine testing of lot release, comparative evaluation of grades, and preparation of technical data sheets using standardized, reproducible results.

Related standards (if applicable)

ISO 28641:2018 was developed in accordance with ISO/IEC Directives and references other ISO documents for procedural and editorial consistency. Users commonly apply this standard alongside other ISO test standards for rubber materials and chemical analysis to create comprehensive quality and compliance programs.

Keywords: ISO 28641:2018, rubber compounding ingredients, organic chemicals, test methods, sampling, density, loss on heating, pH, melting point, quality control.