ASTM D2621-87(2005)

Standard Test Method for Infrared Identification of Vehicle Solids From Solvent-Reducible Paints

SIGNIFICANCE AND USE
The ability to qualitatively identify paint vehicles is useful for characterizing unknown or competitive coatings, for complaint investigations, and for in-process control.
SCOPE
1.1 This test method covers the qualitative characterization or identification of separated paint vehicle solids by infrared spectroscopy within the limitations of infrared spectroscopy.
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.

General Information

• Status: Historical
• Publication Date: 30-Jun-2005
• ICS: 87.060.20 - Binders
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.21 - Chemical Analysis of Paints and Paint Materials

Relations

• Replaces: ASTM D2621-87(2000) - Standard Test Method for Infrared Identification of Vehicle Solids From Solvent-Reducible Paints
• Effective Date: 01-Jul-2005
• Replaced By: ASTM D2621-87(2011) - Standard Test Method for Infrared Identification of Vehicle Solids From Solvent-Reducible Paints
• Effective Date: 01-Jun-2011
• Referred By: ASTM D7588-11(2018) - Standard Guide for FT-IR Fingerprinting of a Non-Aqueous Liquid Paint as Supplied in the Manufacturer's Container
• Effective Date: 01-Jul-2005
• Referred By: ASTM F940-99(2019)e1 - Standard Practice for Quality Control Receipt Inspection Procedures for Protective Coatings (Paint), Used in Marine Construction and Shipbuilding
• Effective Date: 01-Jul-2005
• Referred By: ASTM D6577-15(2019) - Standard Guide for Testing Industrial Protective Coatings
• Effective Date: 01-Jul-2005
• Referred By: ASTM D6763-16(2022) - Standard Guide for Testing Exterior Wood Stains and Clear Water Repellents
• Effective Date: 01-Jul-2005
• Referred By: ASTM D5146-10(2019) - Standard Guide to Testing Solvent-Borne Architectural Coatings
• Effective Date: 01-Jul-2005
• Referred By: ASTM D3168-85(2022) - Standard Practice for Qualitative Identification of Polymers in Emulsion Paints
• Effective Date: 01-Jul-2005

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D2621 – 87 (Reapproved 2005)
Standard Test Method for
Infrared Identification of Vehicle Solids From Solvent-
Reducible Paints
This standard is issued under the fixed designation D2621; 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 5. Significance and Use
1.1 This test method covers the qualitative characterization 5.1 The ability to qualitatively identify paint vehicles is
or identification of separated paint vehicle solids by infrared useful for characterizing unknown or competitive coatings, for
spectroscopy within the limitations of infrared spectroscopy. complaint investigations, and for in-process control.
1.2 This standard does not purport to address all of the
6. Apparatus
safety concerns, if any, associated with its use. It is the
6.1 Spectrophotometer—A recording double-beam infrared
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- spectrophotometerwithawavelengthrangefromatleast2.5to
15 µ m and a spectral resolution of at least 0.04 µm over that
bility of regulatory limitations prior to use.
range. See Practice E275.
2. Referenced Documents
6.2 Demountable Cell Mount, with NaCl window.
2.1 ASTM Standards: 6.3 Vacuum Drying Oven thermostatically controlled to
D1467 Guide for Testing Fatty Acids Used in Protective operate at 60 6 2°C. A water aspirator vacuum source is
Coatings satisfactory.
D1962 Test Method for Saponification Value of Drying 6.4 Oven, Gravity or Forced Draft, capable of maintaining
Oils, Fatty Acids, and Polymerized Fatty Acids temperature from 105 to 110°C.
D2372 Practice for Separation of Vehicle From Solvent-
7. Procedure
Reducible Paints
E131 Terminology Relating to Molecular Spectroscopy 7.1 Placethevehicle,separatedfromthepaintinaccordance
E275 Practice for Describing and Measuring Performance with Practice D2372, on a NaCl window and spread to form a
uniform film. Make sure that the thickness of the film is such
of Ultraviolet and Visible Spectrophotometers
that when the infrared spectrum is recorded, the transmittance
3. Terminology
of the strongest band falls between 5 and 15% (Note). Dry the
3.1 Definitions: film in an oven at 105 to 110°C for 15 min and cool in a
3.1.1 For definitions of terms and symbols, refer to Termi- desiccator.Inspectthefilmvisuallyfordefectssuchasbubbles,
nology E131. wrinkles, contamination, etc. If defects are present, cast an-
other film. If easily oxidizable substances are present such as
4. Summary of Test Method
tung,oiticica,orlinseedoils,makesurethatthefilmisdriedat
4.1 Infraredspectraarepreparedfromdriedfilmsofisolated 60 62°Cinavacuumovenfor1h.Ifsolventsoflowvolatility
paint vehicles. Vehicle types are identified by comparing the
such as cyclohexanone or isophorone are present, the film may
spectra to a collection of reference infrared spectra. need to be dried for several hours in a 60°C vacuum oven.
NOTE 1—Numerous procedures and variations may be used to obtain a
film on which to prepare a suitable spectrum. These include liquid
This test method is under the jurisdiction of ASTM Committee D01 on Paint
mounting between two NaCl plates, transmission through free films, and
and Related Coatings, Materials, andApplications and is the direct responsibility of
Subcommittee D01.21 on Chemical Analysis of Paints and Paint Materials. reflectance from highly polished surfaces.
Current edition approved July 1, 2005. Published August 2005. Originally
7.2 Immediatelyrecordtheinfraredspectrumfrom2.5to15
approved in 1967. Last previous edition approved in 2000 as D2621–87(2000).
µm so that a spectral resolution of 0.04 µm is maintained
DOI: 10.1520/D2621-87R05.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
throughout that range (methods for achieving this resolution
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
willvaryaccordingtothedirectionsofthemanufacturerofthe
Standards volume information, refer to the standard’s Document Summary page on
instrument used).
the ASTM website.
Withdrawn. The last approved version of this historical standard is referenced
on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D2621 – 87 (2005)
TABLE 1 Correlation of Absorption Bands in Alkyd Spectra
−1
Wavelength, µm Wavenumbers, cm Group Vibration
2.9 3448 O–H stretch
3.4 to 3.5 2941 to 2857 alkane C–H stretch
5.8 1724 ester, C=O stretch
6.2, 6.3, 6.6, 6.7 1613, 1587, 1515, 1493 skeletal in-plane aromatic C=C
6.9, 7.3 1449, 1369 aliphatic C–H bending
7.5 to 9.4 1333 to 1063 ester, C–O–C stretch (o-phthalate ester)
8.6 1163 ester, C–O–C stretch (fatty acid ester)
9.6, 13.5, 14.3 1042, 741, 699 out-of-plane aromatic C–H bending denoting o-disubstituted benzene ring.
7.3 Compare the spectrum obtained with reference spectra 8. Keywords
prepared from nonvolatile vehicles of known composition (see
8.1 infrared spectra; paint binders; solvent reducible paint
Annex A1) or consult other published spectra available in the
literature (Annex A3). Interpret the spectrum on the basis of
available information, recognizing certain limitations of infra-
red spectroscopy, and qualifying the interpretation accordingly
(Annex A2).
ANNEXES
(Mandatory Information)
A1. INFRARED SPECTRA OF NONVOLATILE VEHICLES OF KNOWN COMPOSITION
A1.1 A set of reference infrared spectra on grating and
prism is reproduced on the following pages.
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A2. CONSIDERATIONS IN THE INTERPRETATION OF INFRARED SPECTRA OF NONVOLATILE VEHICLES SEPARATED
FROM SOLVENT-TYPE PAINTS
INTRODUCTION
The infrared spectra of vehicles recovered from whole paint are presented in Annex A1. The aim
of this compilation is to aid those using this test method in the practical interpretation of the spectra
they obtain.
Thespectraarecompiledwithonerepresentativespectrumofeachvehiclepresentedinbothaprism
and a grating format. In the discussion of the spectra, the general assignment refers to the first
spectrum. The subsequent spectra discussion will include only those bands which aid in the
identification of the particular modifications being illustrated. In addition, some practical information
is provided where it is believed to be helpful to the analyst. In general, previously noted band
assignments are not repeated.
The data compiled here were obtained from spectra prepared on very carefully calibrated
instruments. In comparing them to spectra prepared in any given laboratory, it is expected that the
wavelength values of absorption bands may differ slightly depending upon the calibration of the
instrument used.
GROUP I-ALKYDS
−1
A2.1 Spectrum 1: Ortho-Phthalic Alkyd, Medium Oil A2.1.7 7.5 to 10.0-µm Region (1333 to 1000 cm )—The
Length
absorption bands in this region are due to the C—O—C
−1
stretching vibrations of the phthalate ester. These absorptions
A2.1.1 2.9-µm Region (3448 cm )—The 2.9-µm band in
are most strongly influenced by the acid portion of the ester
alkyds is due to the O—H stretching vibration. This is usually
rather than the alcoholic portion.
attributed to the unesterified hydroxyl OH on the polyhydric
−1
alcohol used in manufacturing the alkyd. This absorption is
A2.1.8 13.5 and 14.2-µm Regions (741 and 704 cm )—
knowntoincreaseondryingofunsaturatedoilmodifiedalkyds
These two bands are due to out-of-plane bending vibrations of
duetooxidationofthedoublebonds.Thisabsorptionbandcan
ring hydrogens of aromatic compounds having four adjacent
be used to determine the hydroxyl number of alkyds.
hydrogens (orthodisubstitution).
−1
A2.1.2 3.3 to 3.6-µm Region (3030 to 2778 cm )—The
A2.1.9 Comments:
bands in this area are all due to aromatic and aliphatic C–H
A2.1.9.1 Note that in oil-modified alkyds, the intensity of
stretching vibrations.
−1
the absorption at 8.6 µm (1163 cm ) is indicative of the
−1
A2.1.3 5to6-µmRegion(2000to1667cm )—The5.8-µm
amount of oil modification or oil length of the alkyd. In
band in alkyds is due to the combined C=O stretch of the
unmodified alkyds, this band may be little more than a side
phthalateandfattyacidesters.Unreactedphthalicanhydride,if
−1
shoulderonthe8.9-µm(1124-cm )C—O—Cabsorption.The
present, may be detected by the appearance of a sharp
−1 correlationtooillengthisonlyaverygeneraloneinthatwithin
absorption band at approximately 5.6 µm (1786 cm ). Free
a given group of alkyds one may say a sample is a “short,”
carboxyl groups (due to unreacted fatty acid or incompletely
“medium,” or “long” oil type.
reactedphthalicacid)mayoftenbedetectedbytheappearance
A2.1.9.2 Alkyd spectra generally reveal little or no infor-
of a shoulder on the high wavelength (low frequency) side of
the ester carbonyl band. mation concerning the type of combined oil or polyol present.
−1
A2.1.4 6.2 to 6.4-µm Region (1613 to 1563 cm )—The
A2.1.9.3 Identification of polyol and unsaponifiables may
doublet appearing in this region of the spectrum is due to
usually be accomplished by infrared examination of saponifi-
vibrations associated with the double bonds in an aromatic
cation fractions. Identification of the oil acids used usually
ring. The band shape and position of this doublet is character-
requires gas chromatographic analysis of the methylated fatty
istic of non-oil modified, o-phthalic alkyds.
acids recovered by saponification. (For saponification proce-
−1
A2.1.5 6.8 to 6.9-µm Region (1470 to 1449 cm )—This
dures see Guide D1467 and Test Method D1962.)
absorption is produced by C–H bending vibrations of methyl-
ene (scissoring deformation) and methyl (asymmetrical defor-
A2.2 Spectrum 2: Ortho-Phthalic Alkyd, Long Oil
mation) groups in the alkyd. The intensity of this absorption
Length
band will vary with oil length.
−1
−1
A2.2.1 8.6 µm (1163 cm ); fatty acid ester C—O—C
A2.1.6 7.2 to 7.3-µm Region (1389 to 1370 cm )—This
absorption band is due to the C—CH symmetrical deforma- A2.2.2 Comments—Note the difference in the 8.6-µm
−1
(1163-cm ) peak compared to Spectrum 1, due to increased
tion vibration, and is produced by the methyl groups on the
fatty acid chains. oil length.
D2621 – 87 (2005)
A2.3 Spectrum 3: Ortho-Phthalic Alkyd, Tung Oil confirmed by a Lieberman-Storch spot test. Note also the
−1
Modified obscured nature of the 6.3 to 6.5-µm (1587 to 1538-cm )
−1
region. This is most likely due to the salt or “soap” formation
A2.3.1 10.12 µm (988 cm ); –C=C–C=C–C=C– Conju-
with the acids present in the system and the pigment used.
gated triene unsaturation
A2.3.2 Comments—Note the difference in band shapes in
A2.8 Spectrum 8: Ortho-Phthalic Alkyd, p-Phenyl Phenol
−1
the 10 to 10.4-µm region (1000 to 962 cm ) compared to
Modified
Spectra 1 and 2.Absorption due to conjugated unsaturation (in
−1
A2.8.1 11.4 µm (877 cm ) associated with substituted
such oil types as tung, oiticica, dehydrated castor, and conju-
aromatic rings
gated safflower) occurs here. Oil types used for alkyds 1 and 2
−1
A2.8.2 12.1 µm (826 cm ) associated with substituted
contain only isolated double bonds.
aromatic rings
−1
A2.8.3 13.1 µm (763 cm ) associated with substituted
A2.4 Spectrum 4: Ortho-Isophthalic Alkyd
−1 aromatic rings
A2.4.1 7.8 µm (1282 cm ) isophthalate ester C—O—C
−1
A2.8.4 14.4 µm (694 cm ) associated with substituted
−1
A2.4.2 8.2 µm (1220 cm ) isophthalate ester C—O—C
−1 aromatic rings
A2.4.3 8.9 µm (1124 cm ) isophthalate ester C—O—C
A2.8.5 Comments—The main identifying band is the
−1
A2.4.4 13.7µm(730cm )meta-disubstitutedbenzenering
−1
13.1-µm(763-cm )band.Theotherbandsarelessdistinctive,
A2.4.5 Comments—The spectrum of this alkyd is typical of
1−
especially the 14.4-µm (694-cm ) area. It is always best to
an isophthalic alkyd. The major band that identifies this as an
consider the positions of the 3 or 4 absorptions in the far end
−1
isophthalate is the 13.7-µm (730-cm ) band. The presence of
of the curve as a group in assigning the modifying structure.
orthophthalic alkyd can be suspected by comparison to a
straight isophthalic alkyd spectrum (see following) and noting
A2.9 Spectrum 9: Ortho-Phthalic Alkyd, Styrene
−1
the influence of the ortho-phthalate at 7.9 µm (1266 cm ), 9.0
Modified
−1 −1
µm (1111 cm ), 9.4 µm (1064 cm ), and at 14.2 µm (704
−1
A2.9.1 6.7 µm (1493 cm ) aromatic ring vibration
−1
cm ).
−1
A2.9.2 13.2 µm (758 cm ) monosubstituted aromatic (5
adjacent ring hydrogens)
A2.5 Spectrum 5: Ortho-Phthalic Alkyd, Benzoic Acid
−1
A2.9.3 14.3 µm (699 cm ) monosubstituted aromatic (5
Modified
adjacent ring hydrogens)
−1
A2.5.1 14.0 to 14.1 µm (714 to 709 cm ); aromatic ring
A2.9.4 Comments—The very general forebroadening in the
vibrationwhereringcontainsfiveadjacenthydrogens.Position −1
13 to 13.3-µm (769 to 758-cm ) area of the ortho substitution
is characteristic of benzoate esters.
band is characteristic of styrene modification. The 14.3-µm
A
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