Information on the most widely used ASTM standards within the materials testing industry
ASTM D2663: Standard Test Methods for Carbon Black—Dispersion in Rubber
ASTM D2663 test methods cover the degree of dispersion of carbon black in rubber.
Visual dispersion ratings correlate with certain important physical properties of the compound.
A rating of 5 indicates a state of dispersion developing near maximum properties, while a rating of 1 would indicate a state of dispersion developing considerably depressed properties. Normally, the visual dispersion ratings indicate the following levels of compound quality:
| Visual Dispersion Rating | Classification |
| 4 to 5 | High |
| 3 to 4 | Intermediate |
| 2 to 3 | Low |
| 1 to 2 | Very low |
This method is applicable to carbon black or pigmented polyolefin pipes, fittings and compounds with a carbon black content of less than 3 % by weight, and pigment content of less than 5 % by weight.

UNITEDTEST UT3600 Carbon black dispersion tester is used to measure the carbon black dispersion in polyolefin pipes, fittings and compounds. Adaptive to measuring software, and the microscope, measure the size, form, dispersion condition of the carbon black granule, can built the internal connection of this parameter with mechanical property, anti-static function, moisture absorption performance etc., it's an necessary instruments for quality control, new product R&D department. Conform with standard ISO 18553. ASTM D2663
Dispersion Grading:
The DG reference scale is based on ISO 11345.
A test sample image is captured and compared to the reference scale digitally.
A definitive DG (Class) value is calculated automatically.
Why test the level of Carbon Black Dispersion?
| The dispersion influences below physical properties: | ||
| Abrasion resistance | Tensile strength & elongation | Fatigue resistance |
| Tear resistance | Hysteresis | Carbon Blacl< Dispersion affects processability |
| Electron Microscopy | Scanning SEM | Transmission TEM |
| Atomic Force Microscopy | Surface Topography | Optical Microscopy |
| Transmission | Reflectance | |

Related Standard
ISO 18553:2025 Method for the assessment of the degree of pigment or carbon black dispersion in polyolefin pipes, fittings and compounds.
ISO 18553 standard describes a method with two procedures for the assessment of carbon black or pigment particle and agglomerate size, and the rating of dispersion in polyolefin pipes, fittings and compounds.
The method is applicable to polyolefin pipes and fittings, as well as raw material in pellet form, with the choice of procedure to be determined by the referring specification.
The method is applicable to carbon black or pigmented polyolefin pipes, fittings and compounds with a carbon black content of less than 3 % by weight, and pigment content of less than 5 % by weight.
UNITEDTEST UT3600 Carbon black dispersion tester is used to measure the carbon black dispersion in polyolefin pipes, fittings and compounds. Adaptive to measuring software, and the microscope, measure the size, form, dispersion condition of the carbon black granule, can built the internal connection of this parameter with mechanical property, anti-static function, moisture absorption performance etc., it's an necessary instruments for quality control, new product R&D department. Conform with standard ISO 18553, ASTM D2663.
ISO 6964:2019 Polyolefin pipes and fittings — Determination of carbon black content by calcination and pyrolysis — Test method
This standard specifies test methods for the determination of the carbon black content of polyolefin compositions used in particular for the manufacture of pipes and fittings, and provides a basic specification for polyethylene pipes and fittings. ISO 6964 applies equally to the material for manufacture and to any material taken from a pipe or fitting.
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