ASTM D7356/D7356M-13
(Test Method)Standard Test Method for Accelerated Acid Etch Weathering of Automotive Clearcoats Using a Xenon-Arc Exposure Device
Standard Test Method for Accelerated Acid Etch Weathering of Automotive Clearcoats Using a Xenon-Arc Exposure Device
SIGNIFICANCE AND USE
5.1 Acid etch damage is an important warranty claim item for automotive companies. As a result, acid etch resistance is an important parameter for automotive exterior coatings. The method described in this test method has been shown to simulate acid etch damage of automotive clearcoats that occurs when such coatings are exposed from May through mid-August in Jacksonville, FL.3,5 The accelerated test described in this standard allows year-round testing as opposed to the limited outdoor exposure time available for the Jacksonville, FL exposures.
SCOPE
1.1 This test method covers an accelerated exposure test intended to simulate defects in automotive clearcoats caused by acid rain2 that occur at the Jacksonville, Florida exposure site. Exterior exposures at an acid rain test location in Jacksonville, Florida produce etch defects that range from small pits to 12.7 mm [0.5 in.] in diameter or larger acid-etched spots. The latter type of defect is not produced in other acid-etch tests that only produce pits that are smaller than 6.35 mm [0.25 in.] in diameter.3Note 1—Digital images of the acid etch defects produced in outdoor acid-rain exposures and in the accelerated test described in this test method are found in Appendix X1.
1.2 The accelerated test described in this test method uses a xenon-arc light source with daylight filter conforming to the requirements of Practice G155. Specimens are sprayed with a simulated acid rain solution and requires the use of a horizontal, flat specimen array in order to allow the acid rain solution to remain on the test specimens for an extended period of time.
1.3 There is no known ISO equivalent to this test method.
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D7356/D7356M − 13
Standard Test Method for
Accelerated Acid Etch Weathering of Automotive Clearcoats
1
Using a Xenon-Arc Exposure Device
This standard is issued under the fixed designation D7356/D7356M; 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* 1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This test method covers an accelerated exposure test
responsibility of the user of this standard to establish appro-
intendedtosimulatedefectsinautomotiveclearcoatscausedby
priate safety and health practices and determine the applica-
2
acid rain that occur at the Jacksonville, Florida exposure site.
bility of regulatory limitations prior to use.
Exterior exposures at an acid rain test location in Jacksonville,
Florida produce etch defects that range from small pits to 12.7
2. Referenced Documents
mm [0.5 in.] in diameter or larger acid-etched spots. The latter
4
2.1 ASTM Standards:
type of defect is not produced in other acid-etch tests that only
D1293 Test Methods for pH of Water
produce pits that are smaller than 6.35 mm [0.25 in.] in
3 D4517 Test Method for Low-Level Total Silica in High-
diameter.
Purity Water by Flameless Atomic Absorption Spectros-
NOTE 1—Digital images of the acid etch defects produced in outdoor
copy
acid-rain exposures and in the accelerated test described in this test
G113 Terminology Relating to Natural andArtificial Weath-
method are found in Appendix X1.
ering Tests of Nonmetallic Materials
1.2 The accelerated test described in this test method uses a
G147 Practice for Conditioning and Handling of Nonmetal-
xenon-arc light source with daylight filter conforming to the
lic Materials for Natural and Artificial Weathering Tests
requirements of Practice G155. Specimens are sprayed with a
G151 Practice for Exposing Nonmetallic Materials inAccel-
simulated acid rain solution and requires the use of a
erated Test Devices that Use Laboratory Light Sources
horizontal, flat specimen array in order to allow the acid rain
G155 Practice for Operating XenonArc LightApparatus for
solutiontoremainonthetestspecimensforanextendedperiod
Exposure of Non-Metallic Materials
of time.
3. Terminology
1.3 There is no known ISO equivalent to this test method.
3.1 Definitions—Definitions applicable to this standard can
1.4 The values stated in either SI units or inch-pound units
be found in Terminology G113.
are to be regarded separately as standard. The values stated in
each system may not be exact equivalents; therefore, each
3.2 Definitions of Terms Specific to This Standard:
system shall be used independently of the other. Combining 3.2.1 acid rain, n—cloud or rain droplets containing
values from the two systems may result in non-conformance
pollutants, such as oxides of sulfur and nitrogen, to make them
with the standard. acidic.
3.2.2 acid rain spots, n—spots are produced when the sun
evaporates standing water on the vehicle’s surface.
1
This test method is under the jurisdiction of ASTM Committee D01 on Paint 3.2.2.1 Discussion—They fall into two categories, mineral
and Related Coatings, Materials, andApplications and is the direct responsibility of
deposits and acid-etched spots. Mineral deposits are white
Subcommittee D01.27 on Accelerated Testing.
calcium spots or salt deposits left on the surface after water
Current edition approved June 1, 2013. Published September 2013. Originally
evaporates. These deposits can be easily removed with a
approved in 2007. Last previous edition approved in 2007 as D7359 – 07. DOI:
10.1520/D7356_D7356M-13.
pre-wax cleaner (polish) or a clay bar. Acid-etched spots are
2
The acid etch test method is covered by a patent. Interested parties are invited
depressions in the paint or clear coat, which cannot be easily
to submit information regarding the identification of an alternative(s) to this
removed.
patented item to ASTM International Headquarters. Your comments will receive
1
careful considerations at a meeting of the responsible technical committee, which
you may attend.
3 4
Brennan, P. J, Marino, M., Boisseau, J. and Campbell, D., Accelerated Acid For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Etch, Part II: Refined Test Procedure to ReproduceAutomotiveAcid Etch Provides contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Improved Lab Practicality and Proven Correlation, FSCT, 2006 FutureCoat Pro- Standards volume information, refer to the standard’s Document Summary page on
ceedings. the ASTM website.
*A Summary of Changes sec
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7356 − 07 D7356/D7356M − 13
Standard Test Method for
Accelerated Acid Etch Weathering of Automotive Clearcoats
1
Using a Xenon-Arc Exposure Device
This standard is issued under the fixed designation D7356;D7356/D7356M; 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 Scope*
1.1 This test method covers an accelerated exposure test intended to simulate defects in automotive clearcoats caused by acid
2
rain that occur at the Jacksonville, Florida exposure site. Exterior exposures at an acid rain test location in Jacksonville, Florida
produce etch defects that range from small pits to 12.7 mm (0.5 in.)[0.5 in.] in diameter or larger acid-etched spots. The latter type
of defect is not produced in other acid-etch tests that only produce pits that are smaller than 6.35 mm (0.25 in.)[0.25 in.] in
3
diameter.
NOTE 1—Digital images of the acid etch defects produced in outdoor acid-rain exposures and in the accelerated test described in this test method are
found in Appendix X1.
1.2 The accelerated test described in this test method uses a xenon-arc light source with daylight filter conforming to the
requirements of Practice G155. Specimens are sprayed with a simulated acid rain solution and requires the use of a horizontal, flat
specimen array in order to allow the acid rain solution to remain on the test specimens for an extended period of time.
1.3 There is no known ISO equivalent to this test method.
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values given in
parentheses are for information only.stated in each system may not be exact equivalents; therefore, each system shall be used
independently of the other. Combining values from the two systems may result in non-conformance with the standard.
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 and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
4
2.1 ASTM Standards:
D1293 Test Methods for pH of Water
D4517 Test Method for Low-Level Total Silica in High-Purity Water by Flameless Atomic Absorption Spectroscopy
G113 Terminology Relating to Natural and Artificial Weathering Tests of Nonmetallic Materials
G147 Practice for Conditioning and Handling of Nonmetallic Materials for Natural and Artificial Weathering Tests
G151 Practice for Exposing Nonmetallic Materials in Accelerated Test Devices that Use Laboratory Light Sources
G155 Practice for Operating Xenon Arc Light Apparatus for Exposure of Non-Metallic Materials
3. Terminology
3.1 Definitions—Definitions applicable to this standard can be found in Terminology G113.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 acid rain, n—cloud or rain droplets containing pollutants, such as oxides of sulfur and nitrogen, to make them acidic.
1
This test method is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility of
Subcommittee D01.27 on Accelerated Testing.
Current edition approved June 1, 2007June 1, 2013. Published June 2007September 2013. Originally approved in 2007. Last previous edition approved in 2007 as D7359
– 07. DOI: 10.1520/D7356-07. 10.1520/D7356_D7356M-13.
2
The acid etch test method is covered by a patent. Interested parties are invited to submit information regarding the identification of an alternative(s) to this patented item
1
to ASTM International Headquarters. Your comments will receive careful considerations at a meeting of the responsible technical committee, which you may attend.
3
Brennan, P. J, Marino, M., Boisseau, J. and Campbell, D., Accelerated Acid Etch, Part II: Refined Test Procedure to Reproduce Automotive Acid Etch Provides Improved
Lab Practicality and Proven Correlation, FSCT, 2006 FutureCoat Proceedings.
4
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 Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM Inter
...
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