ISO 1306:1995

Overview

ISO 1306:1995 - Rubber compounding ingredients - Carbon black (pelletized) - Determination of pour density describes a laboratory method for measuring the pour (apparent) density of pelletized carbon blacks used in the rubber industry. This fourth edition (1995) replaces the 1987 edition and provides a simple, repeatable procedure for quality control and material specification of pelletized carbon black.

Key topics and technical requirements

• Scope: Applies to all types of pelletized carbon blacks intended for rubber compounding.
• Principle: Weigh a fixed volume of pelletized carbon black and calculate apparent (pour) density from the measured mass and vessel volume.
• Apparatus:
  • Cylindrical vessel, recommended capacity 1 000 cm3 (diameter ~100 mm ±10 mm) with a regular wall and no spout or deformation (other capacities such as 624 cm3 may be used if equivalence is demonstrated).
  • Straight blade or spatula, at least 130 mm long.
  • Balance accurate to 0.1 g.
• Procedure (summary):
  • Tare the cylindrical vessel and pour carbon black vertically to a specified height (not exceeding 50 mm below the rim).
  • Overfill to form a cone, level once with the blade held horizontal and touching the rim, then weigh vessel plus sample.
  • Determine the mass of carbon black (to 1 g where applicable) and compute apparent density (Pap).
  • Note: when using the specified 1 000 cm3 vessel, Pap in g/dm3 is numerically equal to the mass in grams.
• Performance characteristics:
  • Repeatability (single operator): r ≈ 3 kg/m3 - differences greater than this between two tests by the same operator are suspect.
  • Reproducibility (between laboratories): R ≈ 13 kg/m3 - larger differences between labs require investigation.
• Safety: Users must follow standard laboratory safety practices; the standard does not cover all safety aspects.

Applications and users

ISO 1306 is used for:

• Quality control and incoming inspection of pelletized carbon black shipments.
• Batch formulation and volume-to-mass conversions in rubber compounding.
• Supplier specifications, acceptance testing and comparative product evaluation. Typical users:
• Carbon black manufacturers and suppliers
• Rubber compounders and tyre manufacturers
• QC and analytical laboratories
• Standards bodies and testing service providers

Related standards

• ISO 1124:1988 - Rubber compounding ingredients - Sampling procedures for deliveries of carbon black (referenced for sampling practice).

Keywords: ISO 1306, pour density, apparent density, pelletized carbon black, rubber compounding, quality control, laboratory method, pour density determination.