Overview
ISO 5794-1:2022 - Rubber compounding ingredients - Silica, precipitated, hydrated - Part 1: Non-rubber tests specifies laboratory methods to characterize precipitated hydrated silica used as a rubber compounding ingredient. The standard defines sampling, test formulation, mixing procedure (for styrene‑butadiene rubber formulations), methods to determine physical and chemical properties of silica, and the required contents of a test report. It is intended for quality control, specification and product development of precipitated silica for the rubber industry.
Key topics and technical requirements
- Scope and sampling
- Sampling is carried out in accordance with ISO 15528.
- Test matrix (properties and test methods)
- Silica content (ignited sample) - ISO 3262-19:2021
- Colour - ISO 3262-1:2020
- Residue on sieve (45 µm; powder and other forms) - ISO 3262-19:2021 / ISO 787-18
- Volatile matter (loss on heating at 105 °C) - ISO 787-2
- Density - ISO 787-10
- Loss on ignition at 1 000 °C - ISO 3262-1:2020
- pH of slurry - ISO 787-9
- Water‑soluble matter - ISO 787-8
- Total metals: copper, manganese, iron - normative Annexes A–C (acid digestion and AAS)
- Specific surface area - Annexes D and E (including multipoint nitrogen adsorption / BET)
- Granule size distribution - Annex F
- CTAB surface area - Annex G
- Annex H (informative) provides classification of silicas and typical properties.
- Test report requirements (Clause 6) - must reference ISO 5794-1 and include identification, all measured results (14 specified items, including silica content, CTAB and BET surface areas, granule distribution, metal contents, etc.), deviations and unusual observations, and test date.
- Safety - users must follow normal laboratory practice; some methods (e.g., HF digestion) require specific safety measures.
Applications and users
Who uses ISO 5794-1:2022:
- Silica manufacturers - to certify product quality and provide standardized data to customers.
- Rubber compounders and tire manufacturers - for selecting silica grades and ensuring consistent compounding performance with styrene‑butadiene rubber.
- Independent testing and QA laboratories - to perform accredited analyses and produce comparable reports.
- R&D teams - for material characterization during product development and troubleshooting.
Practical benefits:
- Ensures consistent, comparable property data for supply chain specification.
- Supports formulation decisions by providing standard surface area, particle size and impurity data relevant to reinforcement and cure behavior in rubber compounds.
Related standards
Keywords: ISO 5794-1:2022, precipitated hydrated silica, rubber compounding ingredients, CTAB surface area, BET surface area, granule size distribution, total metal content, silica characterization, styrene-butadiene rubber.
Open preview (PDF)Rubber compounding ingredients — Silica, precipitated, hydrated — Part 1: Non-rubber tests
