ASTM D8380-21

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: D8380 − 21
Standard Test Method for
Dry Abrasion Resistance of Hydrophobic and Omniphobic
Coatings
This standard is issued under the fixed designation D8380; 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 This test method describes a procedure for evaluating
D1193Specification for Reagent Water
dry abrasion resistance of a thin hydrophobic or omniphobic
D4060Test Method for Abrasion Resistance of Organic
coating,orboth.Thecoatingistypicallylessthan100nmthick
Coatings by the Taber Abraser
and is applied to a planar, glass substrate by application
D5946Test Method for Corona-Treated Polymer Films Us-
methods including, but not limited to, physical vapor deposi-
ing Water Contact Angle Measurements
tion (PVD), dip, or spray.
D7490TestMethodforMeasurementoftheSurfaceTension
1.2 Units—The values stated in SI units are to be regarded
of Solid Coatings, Substrates and Pigments using Contact
asstandard.Nootherunitsofmeasurementareincludedinthis
Angle Measurements
standard with the exception of angular measurement which are
E177Practice for Use of the Terms Precision and Bias in
reported in degrees.
ASTM Test Methods
E691Practice for Conducting an Interlaboratory Study to
NOTE 1—This test method measures a static contact angle and is not
equivalent to Test Method C813 which measures an advancing contact Determine the Precision of a Test Method
angle.
NOTE 2—Test Method D4060 is not applicable to hydrophobic and 3. Terminology
omniphobiccoatingsbecausethemolecularmonolayerdoesnotgenerally
3.1 Definitions—Definitions used in this test method are in
result in a detectable weight change to the specimen after subjecting it to
accordance withTerminology D16, unless otherwise specified.
abrasion.
1.3 This standard does not purport to address all of the 3.2 Definitions of Terms Specific to This Standard:
safety concerns, if any, associated with its use. It is the 3.2.1 abrasion cycle, n—in abrasion testing, one or more
responsibility of the user of this standard to establish appro- movements of the abradant across a material surface, or the
priate safety, health, and environmental practices and deter- materialsurfaceacrosstheabradant,thatpermitsareturntoits
mine the applicability of regulatory limitations prior to use.
starting position; for this test method, one abrasion cycle is a
1.4 This international standard was developed in accor- complete back and forth motion.
dance with internationally recognized principles on standard-
3.2.2 static contact angle, Ө (degrees), n—the angle be-
ization established in the Decision on Principles for the
tween the substrate surface and the tangent line drawn to the
Development of International Standards, Guides and Recom-
droplet surface at the three-phase point, when a liquid drop is
mendations issued by the World Trade Organization Technical
resting on a plane solid surface (see Fig. 1).
Barriers to Trade (TBT) Committee.
4. Summary of Test Method
2. Referenced Documents
4.1 The coating is applied in a uniform thickness to planar
2.1 ASTM Standards:
glass panels and, after curing, the surface is abraded using a
C813TestMethodforHydrophobicContaminationonGlass
reciprocating rubbing action under controlled conditions of
by Contact Angle Measurement
pressure and abrasive action. Droplets of type IV grade of
reagent water are placed on the surface of the specimen, and
1 the contact angle values are measured and then averaged. The
This test method is under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, andApplications and is the direct responsibility of
test specimen is subjected to abrasion in the same location,
Subcommittee D01.23 on Physical Properties of Applied Paint Films.
until the failure threshold has been reached. Abrasion resis-
Current edition approved Jan. 1, 2021. Published February 2021. DOI: 10.1520/
tance is assessed by measuring the water contact angle within
D8380-21.
theabradedareaofthetestspecimenandreportingthenumber
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
of abrasion cycles.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. NOTE 3—Aglass substrate was selected because the abradant will wear
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D8380 − 21
FIG. 1 Contact Angle Examples
thecoatingbeforesignificantdamagetothesubstrateoccurs,allowingthe
7.1.4 A counter to record the number of abrasion cycles.
failure of the coating to be determined without undesired influence of the
7.2 Abrasion Media, steel wool, grade #0000.
substrate system. Other substrate materials may be used, with the
understanding that surface finish and wear of the substrate may influence
7.3 Contact Angle Meter, or Goniometer, consisting of a
the results.
controlled light source, a stage to hold the test specimen flat
and horizontal, and a microscope or camera for viewing the
5. Significance and Use
droplet on the specimen as described in Test Method D7490;
5.1 The test method is to be used to determine the abrasion
and a means for direct angle measurements.
resistance or mechanical durability of thin omniphobic or thin
7.3.1 Other designs are also acceptable, such as that de-
hydrophobic coatings. These coatings are often used to en-
scribed in Test Method D5946.
hance the surface’s value by promoting fingerprint resistance,
7.4 Syringe, or other dispensing equipment, capable of
water removal, stain resistance, and easy-clean properties. A
providing 2 µL droplet and suitable for use with water-like
comparison of the contact angle and the depreciation of that
liquids.
contact angle due to exposure to mechanical abrasion deter-
minesthecoating’sabilitytoremaineffectiveafterexposureto
8. Reagents and Materials
environmental abrasion.
8.1 Purity of Water—Water meeting the requirements of
5.1.1 Thetestmethodisusedtoappraisetheremovalofthin
Specification D1193 type IV, minimum, should be used for
films when gravimetric measurements will not yield a detect-
testing purposes.
able change in film mass due to the small amount of material
comprising these films, which are on the order of nanometers
9. Test Specimens
thick.
9.1 Apply the coating to a glass panel having both surfaces
5.1.2 Only fully cured specimens are evaluated unless
substantially plane and parallel. Prepare a minimum of one
otherwise specified and agreed upon by the interested parties.
coated panel.
5.2 Differentcoatingmaterialsmaybeevaluatedforrelative
NOTE 4—Typical dimensions for a test panel are 5 cm × 10 cm to 7 cm
durability by evaluating abrasion cycles versus water contact
×14cm.
angle using this method.
9.2 The areas tested shall not contain visible blemishes,
5.3 Different curing or conditioning methods may be evalu-
defects, fingerprints, or any other visible contamination. Clean
ated by preparing test specimens with the same coating and
specimens, as required, prior to testing using material and
then evaluating abrasion resistance using this method.
processesrecommendedbythecoatingmanufactureroragreed
upon by the interested parties.
6. Interferences
6.1 The following factors may interfere with results:
10. Preparation of Apparatus
6.1.1 Dirt, fingerprints, or other contamination on the sur-
10.1 To assist with specimen alignment during testing, a
face being tested.
template of the abrasion path and droplet locations may be
6.1.2 A rough or porous test surface.
created as shown in Fig. 2. For transparent specimens coated
6.1.3 A curved test surface such that angles are difficult to
ononlyonesurface,thetemplatemaybetracedontheopposite
measure.
side of the surface to be tested with a permanent marker. For
transparent specimens coated on both sides or for opaque
7. Apparatus
specimens,thetemplatemaybeindicatedonastripofmasking
7.1 Abrader, consisting of the following elements:
tape loosely adhered to the test surface next to the area to be
7.1.1 A reciprocating sliding specimen platform or move-
abraded.
ment of the test media, capable of horizontal motion in a
10.2 Cut a strip of steel wool approximately 10 mm wide
straight line of 30 mm 6 1 mm at a frequency of 60 cpm 6 5
and20mmlonginthestrandorientationofthefibers.Foldthe
cpm;
strip in half at the midpoint of the long axis to create a double
7.1.2 A rigid test head held perpendicular to the specimen
layer pad. Compress the pad and trim any excess steel wool to
platformthatincludesa10mm 61mmsquare,rubberfriction
obtain a pad 10 mm × 10 mm.
element, and applies a downward force of 10 N 6 0.5 N;
7.1.3 Ameanstoholdthespecimenfirmlysothatitdoesnot 10.3 Adjusttheabraderstrokelengthto30mm 61mmand
slide during the test; speed to a frequency of 60 cpm 6 5 cpm. Ensure the test head
D8380 − 21
FIG. 2 Abrasion Path and Water Drop
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