ASTM D7232-06(2022)

Standard Test Method for Rapid Determination of the Nonvolatile Content of Coatings by Loss in Weight

SIGNIFICANCE AND USE
5.1 This test method is intended for use as a rapid quality control, acceptance, and assessment test. Results are obtained in five to fifteen minutes on most materials. Since the instrument parameters are adjusted to produce the same results as Test Method D2369, which takes over one hour to run, the time and effort expended on determining the optimal conditions for testing a coating with this instrumental method is valuable when numerous measurements are going to be made on different lots or batches of the same material. Also, the automation of the measurement and the calculations should lead to fewer mistakes being made by less-trained operators.
SCOPE
1.1 This test method is used to obtain rapid determination of the weight percent nonvolatile (solids) content via instrumental loss in weight technology. It is not meant as a replacement for Test Method D2369.  
1.2 This test method is principally intended for quality control labs and manufacturing environments where previously characterized materials will be tested repeatedly for different batches or lots.  
1.3 This test method can be used for waterborne and solventborne resins, intermediates and finished paint products. This test method may not be applicable to all types of coatings.  
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.5 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
Note 1: There is no similar or equivalent ISO standard.  
1.6 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: 30-Nov-2022
• ICS: 87.040 - Paints and varnishes
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.21 - Chemical Analysis of Paints and Paint Materials

Relations

• Refers: ASTM D2369-24 - Standard Test Method for Volatile Content of Coatings
• Effective Date: 01-Feb-2024
• Refers: ASTM D16-24 - Standard Terminology for Paint, Related Coatings, Materials, and Applications
• Effective Date: 01-Jan-2024
• Refers: ASTM D16-16 - Standard Terminology for Paint, Related Coatings, Materials, and Applications
• Effective Date: 01-Jul-2016
• Refers: ASTM D2369-10(2015)e1 - Standard Test Method for Volatile Content of Coatings
• Effective Date: 01-Jun-2015
• Refers: ASTM D16-14 - Standard Terminology for Paint, Related Coatings, Materials, and Applications
• Effective Date: 01-Dec-2014
• Refers: ASTM D16-12 - Standard Terminology for Paint, Related Coatings, Materials, and Applications
• Effective Date: 01-Aug-2012
• Refers: ASTM D2369-10e1 - Standard Test Method for Volatile Content of Coatings
• Effective Date: 01-Jul-2011
• Refers: ASTM D16-11a - Standard Terminology for Paint, Related Coatings, Materials, and Applications
• Effective Date: 01-Jun-2011
• Refers: ASTM D16-11 - Standard Terminology for Paint, Related Coatings, Materials, and Applications
• Effective Date: 01-Jan-2011
• Refers: ASTM D2369-10 - Standard Test Method for Volatile Content of Coatings
• Effective Date: 01-Jul-2010
• Refers: ASTM D16-10 - Standard Terminology for Paint, Related Coatings, Materials, and Applications
• Effective Date: 01-Feb-2010
• Refers: ASTM D16-08 - Standard Terminology for Paint, Related Coatings, Materials, and Applications
• Effective Date: 01-Jul-2008
• Refers: ASTM D16-07 - Standard Terminology for Paint, Related Coatings, Materials, and Applications
• Effective Date: 01-Jul-2007
• Refers: ASTM D2369-07 - Standard Test Method for Volatile Content of Coatings
• Effective Date: 01-Jul-2007
• Refers: ASTM D2369-04 - Standard Test Method for Volatile Content of Coatings
• Effective Date: 01-Mar-2004

Overview

ASTM D7232-06(2022), officially titled Standard Test Method for Rapid Determination of the Nonvolatile Content of Coatings by Loss in Weight, provides a rapid and repeatable instrumental procedure to determine the nonvolatile (solids) content in a wide range of coating materials. Developed by ASTM International, this standard is primarily intended for quality control laboratories and manufacturing environments that require efficient testing of multiple batches or lots of previously characterized coating materials. The method can deliver results in as little as five to fifteen minutes, offering a significant advantage over traditional testing procedures such as ASTM D2369.

Key Topics

• Rapid Assessment: Designed for quick determination of nonvolatile content, making it suitable for high-throughput quality control settings.
• Instrumental Loss in Weight Technology: Utilizes a balance and a heating chamber to vaporize volatiles, while remaining solids are measured as the nonvolatile content.
• Versatility: Applicable to waterborne and solventborne resins, intermediates, and finished paint products. The method may not be suitable for all coating types.
• Consistency with Established Methods: The standard allows for adjustment of instrument parameters to align results with ASTM D2369, ensuring consistency across laboratories.
• Automation: By automating measurements and calculations, the method reduces operator error and the need for highly specialized training.
• Repeatability and Reproducibility: The method is validated through interlaboratory studies, confirming its precision for different types of paints and coatings.

Applications

ASTM D7232-06(2022) is widely used in industrial and manufacturing environments where rapid, accurate quality assessment of coatings is essential. Key applications include:

• Quality Control of Paints and Coatings: Ensures batch-to-batch consistency by testing the nonvolatile content of both waterborne and solventborne coatings.
• Production Verification: Allows for frequent testing in manufacturing lines, supporting fast decision-making and process optimization.
• Compliance Testing: Supports compliance with industry requirements for solids content in coatings, aiding in regulatory documentation.
• Acceptance Testing: Serves as a quick acceptance criterion for incoming or outgoing batches of coating materials.
• Process Development: Assists R&D teams in developing new coatings by providing quick feedback on formulation adjustments related to solids content.

Related Standards

For optimal use of ASTM D7232-06(2022) and comprehensive understanding of solids and volatile content in coatings, consider referencing these related ASTM standards:

• ASTM D2369 – Test Method for Volatile Content of Coatings: A commonly used, reference method for determination of volatiles, providing a foundation for the adjustment of D7232 parameters.
• ASTM D16 – Terminology for Paint, Related Coatings, Materials, and Applications: Ensures consistent understanding of key terms and definitions.
• ASTM E180 – Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemicals (Withdrawn): Provides guidance for assessing the precision of test methods.

Note: There is currently no equivalent ISO standard for rapid instrumental determination of nonvolatile content in coatings using this loss in weight method.

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By adopting ASTM D7232-06(2022), organizations benefit from improved efficiency, reduced risk of error, and enhanced comparability of results in the management of coating materials and products. This standard supports robust quality control in diverse sectors, including paint manufacturing, automotive, industrial coatings, and building materials.

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: D7232 − 06 (Reapproved 2022)
Standard Test Method for
Rapid Determination of the Nonvolatile Content of Coatings
by Loss in Weight
This standard is issued under the fixed designation D7232; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D16TerminologyforPaint,RelatedCoatings,Materials,and
Applications
1.1 Thistestmethodisusedtoobtainrapiddeterminationof
D2369Test Method for Volatile Content of Coatings
theweightpercentnonvolatile(solids)contentviainstrumental
E180Practice for Determining the Precision of ASTM
loss in weight technology. It is not meant as a replacement for
Methods for Analysis and Testing of Industrial and Spe-
Test Method D2369.
cialty Chemicals (Withdrawn 2009)
1.2 This test method is principally intended for quality
controllabsandmanufacturingenvironmentswherepreviously
3. Terminology
characterized materials will be tested repeatedly for different
3.1 Definitions:
batches or lots.
3.1.1 The definitions used in this test method are in accor-
1.3 This test method can be used for waterborne and
dance with Terminology D16.
solventborne resins, intermediates and finished paint products.
3.1.2 nonvolatile content, n—the coating material that re-
Thistestmethodmaynotbeapplicabletoalltypesofcoatings.
mains in the pan at the conclusion of the test.
1.4 The values stated in SI units are to be regarded as the
3.2 Definitions of Terms Specific to This Standard:
standard. The values given in parentheses are for information
3.2.1 flip and squish, n—a testing technique that may be
only.
used when the expected nonvolatile content is greater than
1.5 This standard does not purport to address all of the 40%, or when the sample is highly viscous and does not
absorb well into the filter paper.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 3.2.1.1 Discussion—The specimen is applied to the filter
paper on the sample pan, the filter paper is “flipped” over and
priate safety, health, and environmental practices and deter-
the specimen is then “squished” between the filter paper and
mine the applicability of regulatory limitations prior to use.
the sample pan in order to more uniformly distribute the
NOTE 1—There is no similar or equivalent ISO standard.
specimen. In addition, use of this technique forces the glass
1.6 This international standard was developed in accor-
fibers of the filter paper into the specimen, helping to create
dance with internationally recognized principles on standard-
pathways for volatiles release from the specimen and avoiding
ization established in the Decision on Principles for the
incomplete volatiles removal due to “skinning over” of the
Development of International Standards, Guides and Recom-
sample material.
mendations issued by the World Trade Organization Technical
3.2.2 lift, n—theresultofconvectioncurrentscreatedduring
Barriers to Trade (TBT) Committee.
theheatingofthespecimenthatraisesthesamplepanoffofits
support and falsely indicates a weight loss.
2. Referenced Documents
3.2.2.1 Discussion—This effect is compensated for by the
2.1 ASTM Standards:
use of an algorithm that is applied to the digital data.
3.2.3 syringe tare, n—a testing technique that may be used
when the expected nonvolatile content is less than 40%, or
This test method is under the jurisdiction of ASTM Committee D01 on Paint
when the sample is highly volatile and tends to evaporate
and Related Coatings, Materials, andApplications and is the direct responsibility of
rapidly.
Subcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.
3.2.3.1 Discussion—The specimen weight is determined
Current edition approved Dec. 1, 2022. Published December 2022. Originally
approved in 2006. Last previous edition approved in 2016 as D7232 – 06 (2016).
usinganexternalbalancebycalculatingthedifferencebetween
DOI: 10.1520/D7232-06R22.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7232 − 06 (2022)
the syringe weight before (initial weight) and after (final 6.6 Compressed gas regulator(s), as needed to supply N
weight) the specimen is applied to the pan. This difference from high-pressure sources to controlled delivery pressures
between initial and final weight is the actual weight of that are appropriate for the apparatus.
specimen(see10.2),andisusedtominimizeerrorduetorapid
7. Reagents
change of the specimen weight after addition to a heated
sample pan.
7.1 Sodium Tartrate Dihydrate—ACS certified reagent
grade.
4. Summary of Test Method
8. Calibration and Standardization
4.1 The specimen is spread onto a sample pan that is
supported on a balance in a heating chamber that has been 8.1 To maintain the integrity of the test results, the balance
preheated and equilibrated to the specified idle temperature. It
shallbecalibratedusingNIST-traceableweightsandtheheater
is then heated to the specified test temperature to vaporize the shall be calibrated using an NIST-traceable temperature cali-
volatiles. The analysis is completed when the indicated rate of
bration interface per the analyzer manufacturer’s guidelines.
weight loss falls below a rate specified in the test conditions.
8.2 The calibration may be verified using sodium tartrate
The total weight loss is calculated and reported as weight
dihydrate, which has a theoretical water content of 15.66%,
percent nonvolatiles. Both the analyzer’s balance and heater
with an acceptable result range of 15.61% to 15.71%. Other
arecalibratedwithNIST-traceablestandardstoachieveprecise
procedures for materials with known theoretical water content
and accurate results.
are acceptable for verification as specified by the analyzer
4.2 Through adjustment of the analyzer’s parameter manufacturer.
settings, a set of optimal conditions is developed for each
8.3 Prepare the analyzer for use, select the preprogrammed
material type to measure the percent nonvolatiles. These
instrument parameters for sodium tartrate dihydrate (or other
optimal conditions are recorded and may be used for repeat
standard material if applicable) and prepare analyzer for
testing of that material.
analysisasdescribedin9.1usingaflatpanwithoutfilterpaper.
8.4 Initiate the test on the analyzer and follow the prompts
5. Significance and Use
for placing the specimen on the sample pan.
5.1 This test method is intended for use as a rapid quality
8.5 Spreadathin,evenlayerof sodium tartrate dihydrateof
control, acceptance, and assessment test. Results are obtained
appropriate specimen size onto the pan, then close lid to begin
in five to fifteen minutes on most materials. Since the instru-
test. Specimen size shall be determined by analyzer manufac-
ment parameters are adjusted to produce the same results as
turer.
TestMethodD2369,whichtakesoveronehourtorun,thetime
8.6 If results are not within the acceptable range, first
and effort expended on determining the optimal conditions for
perform a temperature calibration, temperature calibration
testing a coating with this instrumental method is valuable
verification, and then a balance calibration to ensure proper
when numerous measurements are going to be made on
analyzer performance. Retest with sodium tartrate dihydrate
different lots or batches of the same material. Also, the
(or other standard material as specified by the instrument
automation of the measurement and the calculations should
manufacturer). If results still are not within the acceptable
lead to fewer mistakes being made by less-trained operators.
range, contact analyzer manufacturer.
6. Apparatus
9. Procedure
6.1 Analyzer, containing:
9.1 Preparing Analyzer for Sample Analysis:
6.1.1 An oven capable of heating the sample to at least
9.1.1 Place the analyzer on a flat, level surface.
225°C.
9.1.2 Establish N purge to the heating chamber per the
6.1.2 A balance capable of measuring to the nearest
instrument manufacturer’s instructions.
0.0001g.
9.1.3 Turn the analyzer on and allow equilibration at the
6.1.3 An electronic means of compensating for lift caused
recommended idle temperature for balance calibration for
by convection currents created during testing.
30min.
6.1.4 A processor that is capable of converting the loss of
9.1.4 Performbalancecalibrationpertheanalyzermanufac-
weight to digital data.
turer’s instructions.
6.1.5 Digital display for presenting the digital data as
9.2 Performing Sample Analysis:
weight percent nonvolatiles.
9.2.1 Programtheanalyzerwiththedesiredtestparameters,
6.2 Flat disposable pan, of aluminum alloy 3003, with
or select the suggested test conditions from Annex A1. See
smooth, uncoated, oil-free surface.
9.3.1 for determining the optimal conditions for testing a
coating. See 9.3.5 for repeat testing of a coating using
6.3 Round glass-fiber filter paper, Grade 111.
previously determined optimal conditions.
6.4 Syringe, 3 cc plastic slip-tip without needle but with
9.2.2 Place a clean, flat sample pan with glass filter paper,
cap, capable of dispensing specimen onto pan.
rough side up, on the pan support and close the lid.Allow the
6.5 Nitrogen compressed gas (N ) – dry and oil-free. analyzer to equilibrate at the desired idle temperature.
D7232 − 06 (2022)
9.2.3 Ensure sample material is thoroughly mixed before 9.2.6 At the end of the test, allow the analyzer to cool and
drawingspecimenintosyringe. Ifusingsyringetaretechnique remove the sample pan. If syringe tare was used, input the
(see 3.2.3), proceed to step 9.2.4. If using flip and squish (see actual specimen weight at the completion of the test to obtain
3.2.1) technique, proceed to step 9.2.5. the final result.
9.2.4 If syringe tare is used: 9.2.7 Record the result as displayed in percent nonvolatiles.
9.2.4.1 Initiate the test on the analyzer and follow the
9.3 Determination of Optimal Test Conditions:
prompts for placing the specimen on the sample pan.
NOTE 2—When determining the optimal test condit
...