ASTM D4217-07(2017)

Standard Test Method for Gel Time of Thermosetting Coating Powder

SIGNIFICANCE AND USE
4.1 This test method is useful for selecting coating powders that gel in the desired time at the specified temperature. The method is not useful for determination of cure time.
SCOPE
1.1 This test method determines the length of time a thermosetting coating powder takes to gel on a polished metal surface at a specified temperature, such as 204°C (400°F). The determination of the gel time is a very simple method for the characterization and quality control of coating powders. However, the gel time determined by this method is not directly related to the time for the coating powder to cure in practical applications.  
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.  
1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-May-2017
• ICS: 83.080.10 - Thermosetting materials
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.51 - Powder Coatings

Relations

• Replaces: ASTM D4217-07(2013) - Standard Test Method for Gel Time of Thermosetting Coating Powder
• Effective Date: 01-Jun-2017
• Referred By: ASTM D3451-06(2017) - Standard Guide for Testing Coating Powders and Powder Coatings
• Effective Date: 01-Jun-2017
• Referred By: ASTM D4242-07(2017) - Standard Test Method for Inclined Plate Flow for Thermosetting Coating Powders
• Effective Date: 01-Jun-2017

Overview

ASTM D4217-07(2017), Standard Test Method for Gel Time of Thermosetting Coating Powder, provides a standardized procedure to determine the gel time of thermosetting coating powders on a polished metal surface at a specific temperature, such as 204°C (400°F). The gel time test is widely used for characterizing and quality control of coating powders, ensuring they perform consistently in manufacturing and industrial applications. However, it's important to note this method does not directly correlate to the cure time of the coating.

Key Topics

• Thermosetting Coating Powders: These powders, when heated, undergo an irreversible chemical reaction leading to a permanent, durable finish. They are often used for substrate protection or decoration, forming a continuous film after application and fusing.
• Gel Time Definition: Gel time is the interval at a given temperature during which a coating powder transforms from a dry solid into a gel-like state. It is a critical indicator for process control in powder coating operations.
• Test Apparatus: Essential equipment includes a hot plate with a precisely maintained surface temperature, a surface-contact thermocouple for accurate temperature measurement, a stopwatch or timer, suitable stirrers, a measuring spoon, and a scraper.
• Safety Considerations: Users must establish appropriate safety and health practices and comply with local regulations when applying this standard.
• Quality Control: The gel time measurement assists manufacturers in selecting the right powder for specific application windows, supporting lot-to-lot consistency in product performance.

Applications

ASTM D4217-07(2017) is essential in various process and quality assurance scenarios involving thermosetting coating powders, particularly in:

• Product Development and Formulation: Researchers and formulators use gel time data to engineer powders with specific application characteristics, ensuring compatibility with intended processing speeds and thermal conditions.
• Quality Assurance Laboratories: Routine gel time testing guarantees that supplied coating powders conform to specification, reducing the risk of defects in the final coated products.
• Manufacturing Process Optimization: Production facilities reference gel time results to adjust application conditions-such as temperature profiles and line speeds-promoting efficient and reproducible coating processes.
• Procurement and Specification: Buyers and specifiers rely on gel time standards to select appropriately performing powders from suppliers, promoting interoperability and product reliability.

Related Standards

• ISO 8130-6:1992, Coating Powders - Part 6: Determination of Gel Time: An international test method paralleling ASTM D4217, though the heating block and procedural details may differ, potentially leading to varied results.
• ASTM D3451, Standard Guide for Testing Coating Powders and Powder Coatings: Offers further guidance on general testing and performance evaluation of powder coatings.
• Industry Best Practices: Ensuring alignment with locally applicable safety, health, and environmental regulations as called out in ASTM D4217.

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ASTM D4217-07(2017) remains a vital tool for manufacturers, laboratories, and industrial users of thermosetting coating powders, promoting consistent quality control, compliance, and process efficiency in powder coating applications. For more information or to purchase the standard, visit ASTM International.

Keywords: gel time, thermosetting coating powder, powder coating, quality control, ASTM D4217, test method, industrial coatings, powder coating test, process optimization.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D4217 − 07 (Reapproved 2017)
Standard Test Method for
Gel Time of Thermosetting Coating Powder
This standard is issued under the fixed designation D4217; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.2 cure time of a coating powder—the time required for
a thermosetting coating powder to sufficiently chemically
1.1 This test method determines the length of time a
crosslink at a given temperature to provide the required coating
thermosetting coating powder takes to gel on a polished metal
properties.
surface at a specified temperature, such as 204°C (400°F). The
3.1.3 gel time of a coating powder—the interval required at
determination of the gel time is a very simple method for the
a given temperature for a coating powder to be transformed
characterization and quality control of coating powders.
from a dry solid to a gel-like state.
However, the gel time determined by this method is not
directly related to the time for the coating powder to cure in
3.1.4 powder coating, n—coatings which are protective or
practical applications.
decorative, or both, formed by the application of a coating
powder to a substrate and fused in a continuous film by the
1.2 This standard does not purport to address all of the
application of heat or radiant energy.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3.1.5 thermosetting, adj—describing a material that, when
priate safety and health practices and determine the applica-
heated per a minimum recommended cure condition, under-
bility of regulatory limitations prior to use.
goes a chemical reaction and a permanent change to a more
1.3 This international standard was developed in accor-
durable state capable of specific properties as designed for
dance with internationally recognized principles on standard-
substrate protection or decoration, or both.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- 4. Significance and Use
mendations issued by the World Trade Organization Technical
4.1 This test method is useful for selecting coating powders
Barriers to Trade (TBT) Committee.
that gel in the desired time at the specified temperature. The
method is not useful for determination of cure time.
2. Referenced Documents
5. Apparatus
2.1 ISO Standards:
5.1 Hot Plate, having an electrically heated metal block
ISO 8130–6:1992 Coating powders—Part 6: Determination
with a polished surface capable of being maintained at tem-
of gel time of thermosetting coating powders at a given
peratures between range 130 to 230°C (266 to 466°F) to within
temperature
62°C (64°F). The temperature should be controlled by means
of a thermoregulator.
3. Terminology
3.1 Definitions: NOTE 1—There are expected differences in results between this method
and ISO 8130–6 which requires a heating block with small depressions.
3.1.1 coating powder, n—finely divided particles of resin,
either thermoplastic or thermosetting, generally incorporating
5.2 Stopwatch or Timer, accurate to at least 1 s.
pigments, fillers, and additives and remaining finely divided
5.3 Stirrer, of very low heat capacity and of suitable size.
during storage under suitable conditions, which, after fusing
Woodenstirrerswithdimensionsof2mmby6mmby130mm
and possibly curing, give a continuous film.
1 1
or ( ⁄16 in. by ⁄4 in. by 5 in.) have been found suitable.
5.4 Surface Contact Thermocouple, suitable for use at 150
to 250°C (300 to 480°F) and reading no greater than 1°C (2°F).
This test method is under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, andApplications and is the direct responsibility of
Subcommittee D01.51 on Powder Coatings.
Current edition approved June 1, 2017. Published June 2017. Originally The sole source of supply of the Model SS-200 hot plate known to the
approved in 1982. Last previous edition approved in 2013 as D4217 – 07 (2013). committee at this time is Thermo-Electric Co., 455 Route 30, Imperial, PA 15126.
DOI: 10.1520/D4217-07R17. If you are aware of alternative suppliers, please provide this information to ASTM
Available from American National Standards Institute (ANSI), 25 W. 43rd St., International Headquarters. Your comments will receive careful consideration at a
4th Floor, New York, NY 10036, http://www.ansi.org. meeting of the responsible technical committee, which you may attend
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