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 for determining the gel time of thermosetting coating powders when applied to a polished metal surface at a specified temperature, commonly at 204°C (400°F). This quick and straightforward test is integral for characterizing and controlling the quality of powder coatings during production and quality assurance processes. The gel time is defined as the interval required at the test temperature for a dry powder to transform into a gel-like state. However, it is important to note that this method is not intended for determining the full cure time of the powder.

Key Topics

• Gel Time Measurement: The main focus of this standard is the determination of gel time, a key property for coating powder selection and process optimization.
• Test Procedure: The method specifies the use of a hot plate with an accurately controlled surface temperature, a fixed sample size, and standardized tools such as a stirrer and timer.
• Terminology: Clear definitions for terms like “gel time,” “coating powder,” “thermosetting,” and “powder coating” are provided to ensure consistent understanding.
• Quality Control Application: By measuring gel time, manufacturers can quickly verify consistency between batches and identify potential process variations.
• Limitations: While valuable for characterizing gel time, this standard does not address the safety concerns related to high temperatures or the determination of cure time for coating powders.

Applications

ASTM D4217-07(2017) is widely used in various industries for:

• Powder Coating Manufacturing: Ensuring consistent gel time across production batches to maintain quality standards.
• Product Development: Selecting or formulating coating powders that meet specific performance criteria, such as gel time requirements for application processes.
• Process Control: Verifying process conditions in industrial environments that apply thermosetting powders for protective or decorative finishes on metal substrates.
• Incoming Materials Inspection: Testing gel time as part of quality checks on received raw materials to confirm supplier compliance before usage in production.
• Technical Documentation: Providing reliable and repeatable data for specifications, certifications, and reference in contracts or regulatory submissions.

Related Standards

Several other standards and documents are closely associated with ASTM D4217-07(2017):

• ISO 8130-6:1992 – Coating powders – Part 6: Determination of gel time of thermosetting coating powders at a given temperature: An international equivalent for gel time determination.
• ASTM D3451 – Guide for Testing Coating Powders and Powder Coatings: Offers broader guidance for various powder coating test methods.
• Other ASTM Powder Coating Standards: For instance, standards on flow, cure, and mechanical property testing.

Practical Value

The precise measurement of gel time according to ASTM D4217 supports manufacturers and users of thermosetting powder coatings in achieving reliable, high-quality coatings. By following the standardized procedure, organizations can:

• Reduce risk of inconsistent coating thickness or application failures.
• Improve quality control efficiency and product performance.
• Facilitate compliance with client requirements and international regulations.

Utilizing ASTM D4217-07(2017) is essential for stakeholders involved in the production, specification, and use of thermosetting coating powders, ensuring products are suited for their intended protective or decorative roles. For more details, refer to the ASTM International website or consult the standard directly.

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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