Overview
ISO 1437:2017 specifies a laboratory method for determining the water-wash sieve residue of regular, untreated carbon black used as a rubber compounding ingredient. The method measures particulate residue retained on a test sieve after washing a known mass of carbon black with controlled water flow. It is not intended for oil‑treated blacks because oil can prevent proper wetting by water.
Key topics and requirements
- Scope: Applies to regular, untreated carbon black for the rubber industry; oil‑treated blacks may be unsuitable.
- Principle: Wash a known test portion through a selected test sieve, dry the retained residue and weigh it to calculate sieve residue.
- Apparatus:
- Test sieves (phosphor bronze or stainless steel) per ISO 565; typical apertures: 500 µm, 125 µm, 45 µm.
- Sieving funnel/container, nozzle, water pressure regulating device, filter with a wire screen at least as fine as the test sieve, rubber hose for washing funnel sides.
- Balance (±0.1 g) and analytical balance (±0.1 mg).
- Gravity‑convection oven capable of 125 °C ±1 °C (uniformity ±5 °C).
- Procedure highlights:
- Clean filter and set water pressure to 0.20 ± 0.04 MPa; pre‑flush sieve for 3 minutes.
- Weigh a test portion (≥100 g) to 0.1 g, add to funnel while water flows; a wetting agent may be used.
- Wash until effluent is clear, rub residue lightly to break agglomerates, wash an additional 2 minutes.
- Dry sieve residue at 125 °C for 1 hour, transfer and weigh to 0.1 mg.
- Expression of results:
- As mg/kg (ppm): R = (mass of residue / mass of test portion) × 10^6
- Or as percentage: R = (mass of residue / mass of test portion) × 100
- Precision: Annex A reports repeatability and reproducibility (pooled values): repeatability r ≈ 37.1%, reproducibility R ≈ 129%. Bias is not determinable for this method.
- Test report must reference ISO 1437 and include sample ID, sieve aperture, apparatus and pressure, results with units, and test date.
Applications and users
ISO 1437:2017 is used by:
- Quality control and testing laboratories in the rubber and tire industry
- Carbon black manufacturers for product specification and production control
- Raw‑materials procurement and materials engineers for incoming inspection
- Certification and compliance testing where sieve residue (fines/coarse particles) affects processing or performance
Related standards
- ISO 565 - Test sieves (nominal opening sizes)
- ISO/TR 9272 - Determination of precision for test method standards (used for precision assessment)
- ASTM D1514 - Comparable ASTM method for carbon black sieve residue (informative reference)
Keywords: ISO 1437, carbon black, sieve residue, rubber compounding ingredients, water‑wash, sieve testing, laboratory method, precision, reproducibility.