Standard Test Method for Laboratory Measurement of Formaldehyde Evolved During the Curing of Melamine-Formaldehyde-Based Coatings

SIGNIFICANCE AND USE
This test method measures the amount of formaldehyde that is evolved from a coating containing melamine-formaldehyde resin(s) during cure at elevated temperature. Cure formaldehyde results from a side-reaction during cross-linking of functionalized polymers with melamine-formaldehyde resins. Cure formaldehyde is evolved in the final bake or cure oven, when the coating temperature is high enough to initiate cross-linking. Formaldehyde can be released from a coating during application, solvent flash-off and cure. Free formaldehyde is primarily evolved during coating application and solvent flash-off. Test Method D 1979  measures “free formaldehyde” in amino resins and Test Method D 6191 measures formaldehyde evolved from coatings at ambient temperature. This method measures only the formaldehyde released during heat cure, which is primarily “cure formaldehyde.”
This test method is not intended to duplicate the evolved formaldehyde from an industrial process, but serves as a reproducible comparative laboratory evaluation.
This test method has not been evaluated with catalyzed coating systems that cure at or below 40°C, such as those used by the wood-finishing industry, and would likely require special adaptation for this application.
SCOPE
1.1 This test method is for the determination of formaldehyde evolved from melamine-formaldehyde-based coatings during the cure step. The results may be used to determine the "cure formaldehyde" evolved from a sample under controlled laboratory conditions.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 This test method is capable of measuring from 500 μg/g to 22 000 μg formaldehyde/g dry coating under the test conditions specified (3 000 ml/min total flow, 50 ml/min DNPH tube flow). The ratio of total flow to DNPH tube flow could be adjusted to extend the range of the method.
1.4 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.

General Information

Status
Historical
Publication Date
30-Jun-2004
Current Stage
Ref Project

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ASTM D6902-04e1 - Standard Test Method for Laboratory Measurement of Formaldehyde Evolved During the Curing of Melamine-Formaldehyde-Based Coatings
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D6902–04
Standard Test Method for
Laboratory Measurement of Formaldehyde Evolved During
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the Curing of Melamine-Formaldehyde-Based Coatings
This standard is issued under the fixed designation D6902; 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
´ NOTE—Paragraph 5.1 was corrected editorially in August 2004.
1. Scope E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
1.1 This test method is for the determination of formalde-
hyde evolved from melamine-formaldehyde-based coatings
3. Terminology
during the cure step. The results may be used to determine the
3.1 Definitions of Terms Specific to This Standard:
“cure formaldehyde” evolved from a sample under controlled
3.1.1 cure formaldehyde, n—the formaldehyde generated as
laboratory conditions.
the result of a chemical reaction during coating curing.
1.2 The values stated in SI units are to be regarded as the
3.1.2 free formaldehyde, n—the residual formaldehyde in a
standard. The values given in parentheses are for information
coating due to the raw materials.
only.
1.3 This test method is capable of measuring from 500 µg/g
4. Summary of Test Method
to 22 000 µg formaldehyde/g dry coating under the test
4.1 Approximately 0.2 g of coating formulation is placed in
conditions specified (3 000 ml/min total flow, 50 ml/min
an aluminum foil pan, dried in a vacuum oven at 40°C (to
DNPH tube flow). The ratio of total flow to DNPH tube flow
remove free formaldehyde and solvents) and then baked at the
could be adjusted to extend the range of the method.
optimum process cure temperature for 30 min. Formaldehyde
1.4 This standard does not purport to address all of the
emissions are collected from the cure chamber on a DNPH/
safety concerns, if any, associated with its use. It is the
Silica tube, which is then extracted and the extract analyzed by
responsibility of the user of this standard to establish appro-
HPLC/UV. The amount of formaldehyde evolved from the
priate safety and health practices and determine the applica-
coating during the cure step is calculated on both a wet-weight
bility of regulatory limitations prior to use.
and dry-weight basis. The test is run in triplicate plus a blank
and system standard.
2. Referenced Documents
2
2.1 ASTM Standards:
5. Significance and Use
3
D362 Specification for Industrial Grade Toluene
5.1 This test method measures the amount of formaldehyde
D1979 Test Method for Free Formaldehyde Content of
3 that is evolved from a coating containing melamine-
Amino Resins
formaldehyde resin(s) during cure at elevated temperature.
D6191 Test Method for Measurement of Evolved Formal-
Cure formaldehyde results from a side-reaction during cross-
dehyde from Water Reducible Air-Dry Coatings
linking of functionalized polymers with melamine-
formaldehyde resins. Cure formaldehyde is evolved in the final
bake or cure oven, when the coating temperature is high
1
This test method is under the jurisdiction of ASTM Committee D01 on Paint
enough to initiate cross-linking. Formaldehyde can be released
and Related Coatings, Materials, andApplications and is the direct responsibility of
Subcommittee D01.21 on Chemical Analysis of Paints and Paint Materials. from a coating during application, solvent flash-off and cure.
Current edition approved Aug. 3, 2004. Published July 2004. Originally
Free formaldehyde is primarily evolved during coating appli-
approved in 2003. Last previous edition approved in 2003 as D6902 – 03. DOI:
cation and solvent flash-off. Test Method D1979 measures
10.1520/D6902-04E01.
2
“free formaldehyde” in amino resins and Test Method D6191
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
measures formaldehyde evolved from coatings at ambient
Standards volume information, refer to the standard’s Document Summary page on
temperature. This method measures only the formaldehyde
the ASTM website.
3 released during heat cure, which is primarily “cure formalde-
Withdrawn. The last approved version of this historical standard is referenced
on www.astm.org. hyde.”
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D6902–04
5.2 Thistestmethodisnotintendedtoduplicatetheevolved 7. Reagents and Materials
formaldehyde from an industrial process, but serves as a
7.1 Purity of Reagents—Use reagent grade chemicals in all
reproducible comparative laboratory evaluation.
...

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