Overview
ISO 61:2023 is an internationally recognized standard published by ISO that specifies a precise method for determining the apparent density of plastics moulding materials that cannot be poured from a specified funnel. Unlike ISO 60, which covers materials free-flowing through a funnel, ISO 61 focuses on loose, slice, granular, or powder moulding materials that require a different testing approach due to their flow characteristics.
The apparent density, defined as the mass per unit volume of a material in its natural dry state, is an important parameter used in quality control, material specification, and processing optimization in the plastics industry. This second edition updates technical details and testing procedures, providing improved clarity for consistent and reliable results.
Key Topics
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Scope and Application
This standard applies specifically to loose moulding materials that cannot be poured through a traditional funnel, such as powders and granular forms, where evaluating apparent density using other methods is impractical.
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Apparatus Requirements
The test requires specific equipment:
- A balance accurate to 0.1 g
- A ruler with 1 mm accuracy
- A measuring cylinder with a capacity of approximately 1000 ml and a smooth inner surface
- A weighted plunger designed to compact the material uniformly during testing
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Test Procedure
The method involves:
- Gradually dropping 60 ± 0.2 g of the loose moulding material into the measuring cylinder, ensuring a level surface
- Slowly lowering a weighted plunger onto the material and allowing it to rest for 1 minute
- Measuring the height of the compacted material to the nearest millimeter
- Repeating the measurement three times to ensure reproducibility
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Calculating Apparent Density
Apparent density (d) is calculated with the formula:
d = m / (A × h)
where m is the mass in grams, A is the cross-sectional area of the cylinder in cm², and h is the height of the material in cm. Results are reported in grams per milliliter (g/ml), consistent with ISO 60 conventions.
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Reporting
Test reports must reference ISO 61:2023 and include detailed test data: sample identification, individual and mean results, statistical variability (standard deviation or coefficient of variation), observations, and test dates.
Applications
ISO 61:2023 is essential in various practical scenarios, including:
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Material Quality Control
Manufacturers and suppliers of plastics use this standard to ensure consistent apparent density, which impacts mould filling and final product characteristics.
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Process Optimization
Knowing the apparent density of granular or powder moulding materials helps optimize processing parameters such as dosing, mixing, and mould filling during production.
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Research and Development
Material scientists studying new plastic compounds or formulations rely on this standard to quantitatively compare physical properties of non-flowable materials.
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Regulatory Compliance and Specification
Compliance with internationally accepted standards facilitates trade, product certification, and customer confidence in materials used for thermosetting plastics applications.
Related Standards
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ISO 60 - Plastics – Determination of apparent density of material that can be poured from a specified funnel
Complements ISO 61 by covering free-flowing moulding materials, enabling comprehensive apparent density analysis across plastic material types.
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ISO/IEC Directives
Provides guidelines on the development and maintenance of ISO standards, ensuring quality and consistency.
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Other ISO 61 Series Standards
Referenced for additional physical property tests relevant to plastics materials characterization.
Keywords: ISO 61:2023, apparent density, plastics moulding materials, non-flowable material, granular plastics, powder plastics, measuring method, plastic standards, quality control, thermosetting materials, plastic molding, ISO plastics standards.
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