Overview
SIST EN ISO 8130-7:2019 is an international standard developed by CEN and ISO that specifies a method for determining the loss of mass on stoving of coating powders. This standard applies to coating powders designed for application via electrostatic spraying, flock spraying, or fluidized bed techniques. The test focuses on measuring the volatile content, including water, lost during heating (stoving), which is crucial for quality control and performance assessment of powder coatings.
This standardized testing method is practical and straightforward, offering reliable results especially for powders losing around 2% by mass during stoving. For losses exceeding 2%, the accuracy diminishes. The test complements thermogravimetric analysis methods such as those in the ISO 11358 series.
Key Topics
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Scope and Purpose
Defines the procedure to quantify mass loss due to volatiles during heating, ensuring coating powders meet performance criteria.
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Test Method
- Use of a flat-bottomed tinplate or aluminum dish for sample placement.
- Precise weighing before and after heating to determine loss.
- Heating performed in an air-circulation oven at specified temperatures (up to 250 °C).
- Controlled environment with recorded ambient temperature and humidity.
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Test Parameters
Common parameters include:
- Test portion mass: approximately 0.5 g
- Heating time: typically 20 minutes to 24 hours depending on powder type
- Temperature range: 50 °C for thermoplastics, 180-200 °C for standard thermosetting powders, and above 200 °C for high-cure thermosetting powders.
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Result Calculation
Loss of mass expressed as a percentage using the formula:
L (%) = [(m0 - m1) / (m0 - m)] × 100
where m is dish mass, m0 is dish + powder before stoving, and m1 is dish + residue after stoving.
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Test Reporting
Required information includes product identification, oven type, environmental conditions, test parameters, results, deviations, and observations.
Applications
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Quality Control for Powder Coatings
Ensures volatile content is within specification, impacting coating performance such as adhesion, curing, and durability.
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Process Optimization
Manufacturers utilize this test to refine curing schedules and reduce defects caused by leftover volatiles or moisture.
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Research and Development
Facilitates comparison between powder formulations and evaluation of new materials under standardized conditions.
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Regulatory Compliance
Supports conformance with international coating powder standards for industrial applications in automotive, appliances, and construction sectors.
Related Standards
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ISO 8130 Series - The broader series on coating powders covers additional aspects such as vocabulary (ISO 8130-14) and other test methods.
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ISO 15528 - Sampling of paints, varnishes, and raw materials, referenced for obtaining representative powder samples.
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ISO 11358 Series - Thermogravimetric analysis for characterizing volatile contents in polymers, used as a complementary comparative method.
By adhering to SIST EN ISO 8130-7:2019, industry professionals can reliably assess the loss of mass on stoving, supporting consistent production quality and enhanced performance of powder coatings applied by electrostatic or fluidized bed methods. This standard is a vital tool for manufacturers, laboratories, and quality assurance specialists working with coating powders worldwide.