ASTM D2743-68(1998)
(Practice)Standard Practices for Uniformity of Traffic Paint Vehicle Solids by Spectroscopy and Gas Chromatography
Standard Practices for Uniformity of Traffic Paint Vehicle Solids by Spectroscopy and Gas Chromatography
SCOPE
1.1 These practices provide general information on the instrumental techniques available for detecting adulteration or nonuniformity of the chemical nature of the vehicle solids in purchased lots of traffic paints by means of the individual or combined use of infrared and ultraviolet spectroscopy and gas chromatography. The procedures given are applicable when traffic paint is selected and purchased on the basis of pre-qualification laboratory or road performance tests, or both, and a reference sample of the original paint so evaluated and selected is retained and compared with test samples representative of subsequent purchased and delivered lots of such paint and which are required to be the same as the original reference sample.
1.2 Although not specifically provided for in these practices, the methods given may also be applied, with appropriate modification, to evaluating the acceptability of traffic paints that have been purchased on the basis of composition specifications. In such cases, application is limited to the vehicle solids as before, as well as the availability of a suitable standard or range of standards representative of the vehicle solids that are acceptable and with which samples of subsequent delivered lots will be compared.
1.3 The techniques provided are wholly adequate for detecting gross adulteration of the vehicle solids where completely different drying oils, resins, or polymers, or combinations of these have been substituted for those originally contained in the reference sample. In cases of lesser adulteration or modification, these methods have been found adequate for detecting vehicle solids, adulterations, or modifications as low as 5 weight% of the vehicle solids.
1.4 These techniques have been developed on the basis of cooperative work with alkyd, chlorinated rubber-alkyd, and poly(vinyl toluene) type paints involving the detection of nonuniformity when such extraneous materials as rosin, fish oil, hydrocarbon resin, and chlorinated paraffin have been added. The procedures given may be, but are not necessarily completely applicable to all other types of vehicle solids or extraneous additions, or both.
1.5 The methods provided appear in the following order: Section Method A---Infrared Spectral Analysis of Total Vehicle Solids 10 to 12 Method B---Infrared Spectral Analysis of Unsaponifiable Matter from Vehicle Solids 13 to 15 Method C---Gas Chromatographic Analysis of Oils and Oil Acids Separated from Vehicle Solids 16 to 18 Method D---Ultraviolet Spectral Analysis of Total Vehicle Solids 19 to 21
1.6 This standard does not purport to address all of the safety problems, 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.>
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Designation: D 2743 – 68 (Reapproved 1998)
Standard Practices for
Uniformity of Traffic Paint Vehicle Solids by Spectroscopy
and Gas Chromatography
This standard is issued under the fixed designation D 2743; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope oil, hydrocarbon resin, and chlorinated paraffin have been
added. The procedures given may be, but are not necessarily
1.1 These practices provide general information on the
completely applicable to all other types of vehicle solids or
instrumental techniques available for detecting adulteration or
extraneous additions, or both.
nonuniformity of the chemical nature of the vehicle solids in
1.5 The methods provided appear in the following order:
purchased lots of traffic paints by means of the individual or
Section
combined use of infrared and ultraviolet spectroscopy and gas
Method A—Infrared Spectral Analysis of Total Vehicle Solids 10-12
chromatography. The procedures given are applicable when
Method B—Infrared Spectral Analysis of Unsaponifiable Mat-
traffic paint is selected and purchased on the basis of pre-
ter from Vehicle Solids 13-15
Method C—Gas Chromatographic Analysis of Oils and Oil
qualification laboratory or road performance tests, or both, and
Acids Separated from Vehicle Solids 16-18
a reference sample of the original paint so evaluated and
Method D—Ultraviolet Spectral Analysis of Total Vehicle Sol-
selected is retained and compared with test samples represen- ids 19,20, and 21
tative of subsequent purchased and delivered lots of such paint
1.6 This standard does not purport to address all of the
and which are required to be the same as the original reference
safety concerns, if any, associated with its use. It is the
sample.
responsibility of the user of this standard to establish appro-
1.2 Although not specifically provided for in these prac-
priate safety and health practices and determine the applica-
tices, the methods given may also be applied, with appropriate
bility of regulatory limitations prior to use.
modification, to evaluating the acceptability of traffic paints
that have been purchased on the basis of composition specifi-
2. Referenced Documents
cations. In such cases, application is limited to the vehicle
2.1 ASTM Standards:
solids as before, as well as the availability of a suitable
D 1259 Test Methods for Nonvolatile Content of Resin
standard or range of standards representative of the vehicle
Solutions
solids that are acceptable and with which samples of subse-
D 1397 Test Method for Unsaponifiable Matter in Alkyd
quent delivered lots will be compared.
Resins and Resin Solutions
1.3 The techniques provided are wholly adequate for detect-
D 2245 Test Method for Identification of Oils and Oil Acids
ing gross adulteration of the vehicle solids where completely
in Solvent-Reducible Paints
different drying oils, resins, or polymers, or combinations of
D 2372 Practice for Separation of Vehicle from Solvent-
these have been substituted for those originally contained in the
Reducible Paints
reference sample. In cases of lesser adulteration or modifica-
D 2621 Test Method for Infrared Identification of Vehicle
tion, these methods have been found adequate for detecting
Solids from Solvent-Reducible Paints
vehicle solids, adulterations, or modifications as low as 5 4
E 105 Practice for Probability Sampling of Materials
weight % of the vehicle solids.
E 131 Terminology Relating to Molecular Spectroscopy
1.4 These techniques have been developed on the basis of
cooperative work with alkyd, chlorinated rubber-alkyd, and
3. Terminology
poly(vinyl toluene) type paints involving the detection of
3.1 For definitions of terms and symbols, refer to Terminol-
nonuniformity when such extraneous materials as rosin, fish
ogy E 131.
1 2
These practices are under jurisdiction of ASTM Committee D-1 on Paint and Annual Book of ASTM Standards, Vol 06.01.
Related Coatings, Materials, and Applications and are the direct responsibility of Annual Book of ASTM Standards, Vol 06.03.
Subcommittee D01.44 on Traffic Coatings. Annual Book of ASTM Standards, Vol 14.02.
Current edition approved Aug. 15, 1968. Published October 1968. Annual Book of ASTM Standards, Vol 03.06.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 2743
4. Summary of Methods many minor adulterations may not always show characteristic
infrared spectral differences. Therefore, in such cases it is best
4.1 Each of the methods given requires both a reference and
to proceed to additional tests as given in Methods B and C or
a test sample of traffic paint and a preliminary separation and
else alternatively directly to Method D.
removal of the pigment component in each.
5.3 Method B is useful in detecting adulterations that are
4.2 Method A involves infrared spectral analysis of cast
unsaponifiable or else have an unsaponifiable component that
films of the total vehicle solids to detect spectral differences
between the reference and test samples caused by gross or has escaped detection in Method A only because the adulterant
minor adulteration of the test sample.
may have been small in amount and therefore its strong
4.3 Method B involves infrared spectral analysis of cast spectral peaks may have been masked over by the rest of the
films of the unsaponifiable matter that has been separated from vehicle solids. Some care should be taken in interpreting
the vehicle solids in order to detect spectral differences
spectral differences in Method B to avoid an erroneous
between the reference and test samples caused by lesser
conclusion that the test sample is unacceptable because its
adulterations of an unsaponifiable nature and which was not
spectrum is different. Apparent but unreal differences can occur
readily evident when using Method A.
as a result of incomplete saponification, failure to remove all
4.4 Method C involves gas chromatographic analysis of
saponifiable material, and varying degrees of contamination of
prepared methyl esters of the separated fatty acids obtained
the unsaponifiable fraction with sterols, etc., present in the
from the vehicle solids in order to detect chromatographic
vehicle solids. After it has thus been firmly established that a
differences between the reference and test samples caused by
real spectral difference does exist, further tests are unnecessary,
either gross or lesser adulteration of the drying oil fraction with
except that it is wise to resort again to the published literature
extraneous drying oils which may not have been readily
on infrared to attempt to identify the possible nature of the
evident by the use of Methods A and B.
adulterant. Where Methods A and B indicate acceptability of
4.5 Method D involves quantitative ultraviolet spectral
the test sample, it is still not always possible to rule out
analysis of the total vehicle solids dissolved in a nonaromatic
adulteration caused by changes or modifications in the saponi-
spectral grade solvent to give precise concentrations in order to
fiable portion, that is, the type of fatty acid, dibasic acids, and
detect ultraviolet spectral absorbance differences between the
polyol. In such cases, it is best to continue on to Method C for
reference and test samples caused by minor or sophisticated
determination of the oil acids, and to other gas chromato-
adulterations of the vehicle solids and which may not be
graphic methods for the polyol and dibasic acids when such
readily detected by Method A. Method D is to be used as an
equipment is available.
alternative to Methods B and C.
5.4 Method C is extremely sensitive in detecting adultera-
tions and changes that have been made in the oil or fatty acid
5. Selection of Test Methods and Significance and Use
portion of the vehicle solids. It can, for example, detect
5.1 All of the methods provided involve comparisons be-
whether linseed, coconut, oiticica, etc., has been substituted for
tween the spectra or chromatograms of the reference and test
soya oil and vice versa, or whether fish or tall oil has partially
samples to determine if they show significant differences. It is
or wholly replaced some other drying oil, etc. Consequently,
not possible at this time to establish quantitative limits as a
when the results of Methods A and B suggest that the test
guide to whether a spectral or chromatographic difference is
sample is acceptable and where a drying oil component is
truly significant. Certainly the presence or absence of a
known to be present, Method C should be used additionally for
moderate or strong peak in the test sample which is not evident
more complete assurance of product uniformity. Where the
in the reference is significant. A persistent difference in the
results from Method C along with those from Methods A and
ratios of two peaks of one spectrum as compared to the
B indicate product uniformity, it is a fairly safe assumption that
reference sample is significant. On the whole, some judgment
the product has not been significantly altered.
must be exercised in this respect and it is advisable to refer to
5.5 Method D is intended as an alternative to Methods B
published data on infrared or gas chromatography in order to
and C and where the results from Method A indicate apparent
establish, where feasible, the possible overall nature of the
product acceptability. Method D, by the use of quantitative
adulterant or its functional group which might be causing the
ultraviolet spectral absorbance data, is an extremely sensitive
comparison spectra to differ.
procedure for the detection of complete or even partial adul-
5.2 Method A is rapid and the most convenient of the
teration of the test sample. However, considerable caution must
procedures given. It should be utilized first in order to detect
be exercised in the preliminary pre-drying of the vehicle solids
nonuniformity of the test sample. Significant spectral differ-
since it is at this stage that the components are extremely
ences from that of the reference sample can be taken as an
sensitive to oxidative changes. Even minor oxidative changes
indication of adulteration and in such cases the use of the other
can seriously affect the absorbance data obtained in ultraviolet
methods is not necessary. As a general rule. Method A is
spectral analysis and may give an impression that the two
sufficient to detect gross or major adulteration of the vehicle
samples being compared are different when in fact they are the
solids. However, where Method A shows no significant spectral
same. When these considerations are provided for, and the
differences, it cannot be assumed that the test sample is
completely acceptable since changes in the type of drying oil, comparison spectra are identical in Method D as well as in
Method A, then it can be assumed that the sample is acceptable.
polyol, and certain dibasic acids in alkyd resins, addition of
certain aliphatic or nonfunctional hydrocarbon resins, and Significant differences in the spectra from Method D would
D 2743
indicate nonuniformity of the product even though Method A 12. Interpretation of Results
may fail to reveal such nonuniformity.
12.1 Compare the companion spectra from the test and
reference samples for identity by visual inspection preferably
6. Reference Sample
over a light box. Note particularly the presence of an extrane-
6.1 The reference sample of traffic paint should be at least
ous peak or peaks in one which is (are) not in the other. Also
250 mL and should be truly representative of the initial paint
note the ratio of intensities of two adjacent or pairs of peaks on
found acceptable in pre-qualification laboratory or field service
one spectra and determine whether this ratio is similar on the
tests, or both, and which paint is subsequently specified for
comparison spectra. Any significant difference should be con-
purchase.
sidered as an indication of lack of uniformity between the
6.2 In cases where paint is purchased on the basis of
reference and test samples. Attempt to ascribe this difference to
formulation specifications and it is desired to utilize these
some extraneous component or formulation difference between
procedures to detect adulteration in delivered lots of paint,
the comparison samples by referring to available infrared
reference samples may be synthetically prepared to represent
literature and published spectra. Where it is evident that the
the extremes of the range that will be permitted in the
comparison spectra are significantly different, no further tests
formulation.
are necessary. When the spectra are identical, proceed to
Methods B and C or alternatively to Method D for a fuller
7. Test Sample
evaluation of possible minor or more sophisticated adultera-
7.1 The test samples of the traffic paint should be at least
tion.
250 mL and should be representative of each delivered lot of
paint that was specified for purchase and which is intended to
METHOD B—INFRARED SPECTRAL ANALYSIS
be the same as the initial reference paint used in the pre-
OF UNSAPONIFIABLE MATTER FROM VEHICLE
qualifications acceptance tests from which a reference sample
SOLIDS
was retained.
13. Apparatus
8. Sampling Reference and Test Samples
13.1 Same as in 10.1.
8.1 Test and reference samples of the traffic paint should be
obtained in accordance with Practice E 105.
14. Procedure
14.1 Treat a portion of the separated vehicle from both the
9. Preparation of Samples
sample and reference paints so as to obtain an ether solution of
9.1 Separate the vehicle from the pigment by centrifuging
the unsaponifiable matter in accordance with Test Method
the paint in accordance with Practice D 2372. Transfer and
D 1397. Take care to ensure rigorous quantitative separations
preserve the vehicle in a well-stoppered amber bottle.
and similar handling and exposure of the comparison samples.
Determine the percentage of unsaponifiable matter. Obtain
METHOD A—INFRARED SPECTRAL ANALYSIS
infrared spectra of cast films of the dried unsaponifiable matter
OF TOTAL VEHICLE SOLIDS
in a manner similar to that described in 11.1.
10. Apparatus
15. Interpretation of Results
10.1 Infrared Spectrophotometer, recording double-beam,
15.1 Compare the percentages of unsaponifiable matter.
and accessory equipment as described in Test Method D 2621.
Compare the spectra and interpret the results in a similar
11. Procedure
manner as in 12.1. Care should be taken to avoid an erroneous
conclusion that the materials are differen
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