Overview
ISO 787-11:1981 specifies a general test method for determining the tamped volume and apparent density after tamping of pigments and extenders. This international standard issued by ISO (International Organization for Standardization) provides a precise laboratory procedure to measure the bulk characteristics of dried pigment or extender powders after mechanical tamping. The standard replaces the earlier ISO Recommendation ISO/R 787/11-1970 and forms part 11 of the broader ISO 787 series on general test methods for pigments and extenders.
The procedure is particularly important for quality control and specification compliance in paint, coatings, and related industries where accurate measurement of pigment and filler materials' packing density impacts product performance.
Key Topics
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Sample Preparation
Samples are dried in an oven at 105 ± 2 °C to remove moisture, then passed through a specified sieve mesh to eliminate agglomerates and ensure uniform particle size distribution.
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Apparatus and Equipment
The main equipment includes:
- A 250 ml graduated measuring cylinder (ISO 4788 standard) for sample volume measurement.
- A tamping volumeter with a support system applying approximately 1,250 revolutions in steps to compact the sample.
- Balance with precision of ±0.5 g.
- Oven for drying and desiccator for cooling.
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Tamping Procedure
The sample is placed into the cylinder carefully to avoid air pockets, weighed, and subjected to mechanical tamping. Tamping progresses in cycles until the volume difference between two successive cycles is less than 2 ml, indicating stable compaction.
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Volume and Density Calculations
The volume massique apparent (apparent volume) and masse volumique apparente (apparent density) after tamping are calculated based on the mass of the sample and the tamped volume, using the formulas defined in the method.
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Test Reporting
The test report must include product identification, reference to ISO 787-11, test results, any procedural modifications, and date. Results should be reproducible with a margin of 1 ml or 0.01 g/ml precision.
Applications
ISO 787-11:1981 is essential for industrial and laboratory environments involved with:
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Pigment and Extender Quality Control
Ensuring uniform density characteristics of additives before incorporation into paints, coatings, inks, and plastics.
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Product Specification and Compliance
Providing standardized data supporting pigment and extender specifications related to packing density and bulk properties.
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Material Performance Assessment
Bulk density and tamped volume values help predict handling, dispersion behavior, and final product consistency.
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Process Optimization
Assists manufacturers in adjusting particle size distribution, drying conditions, and mechanical processing to achieve desired density parameters.
Related Standards
ISO 787-11 is part of the ISO 787 series, which includes general test methods covering various pigment and extender properties:
- ISO 787-1: Color Comparison of Pigments
- ISO 787-2: Determination of Volatile Matter at 105 °C
- ISO 787-10: Determination of Density Using a Pycnometer
- ISO 787-23: Density Determination Using a Centrifuge
Additional related standards include:
- ISO 565: Test Sieves - Dimensions of Metal Woven Wire Meshes (Referenced for sieve mesh size in sample preparation)
- ISO 4788: Laboratory Glassware - Graduated Cylinders (Specifies the cylinders used for volume measurements)
Using ISO 787-11 in conjunction with these standards ensures a comprehensive evaluation of pigment and extender materials, supporting reliable and consistent material characterization globally.
Keywords: ISO 787-11, pigments test methods, extenders testing, tamped volume, apparent density, pigment quality control, paint industry standards, pigment bulk density, pigment specification, pigment tamping test, ISO paint standards.