ASTM D4213-24

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Designation: D4213 − 08 (Reapproved 2016) D4213 − 24
Standard Test Method for
Scrub Resistance of Paints by Abrasion Weight Loss
This standard is issued under the fixed designation D4213; 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
1.1 This test method covers an accelerated procedure for determining the resistance of paints to erosion caused by scrubbing.
(Note: The term wet abrasion is sometimes used for scrubbing, and wet abrasion resistance or scrubbability for scrub resistance.)
Although scrub resistance tests are intended primarily for interior coatings, they are sometimes used with exterior coatings as an
additional measure of film performance.
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 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 healthsafety, health, and environmental practices and determine
the applicability of regulatory limitations prior to use.
1.4 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.
2. Referenced Documents
2.1 ASTM Standards:
D562 Test Method for Consistency of Paints Measuring Krebs Unit (KU) Viscosity Using a Stormer-Type Viscometer
D1193 Specification for Reagent Water
D1475 Test Method for Density of Liquid Coatings, Inks, and Related Products
D2486 Test Methods for Scrub Resistance of Wall Paints
D3450 Test Method for Washability Properties of Interior Architectural Coatings
D3980 Practice for Interlaboratory Testing of Paint and Related Materials (Withdrawn 1998)
D4828 Test Methods for Practical Washability of Organic Coatings
E70 Test Method for pH of Aqueous Solutions With the Glass Electrode
E180 Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemicals
(Withdrawn 2009)
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Summary of Test Method
3.1 The material under test is applied to a black plastic scrub test panel, and after drying one week, a section of the test panel is
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 D01.42 on Architectural Coatings.
Current edition approved Dec. 1, 2016Feb. 1, 2024. Published December 2016February 2024. Originally approved in 1983. Last previous edition approved in 20122016
as D4213 – 08 (2012).(2016). DOI: 10.1520/D4213-08R16.10.1520/D4213-24.
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volume information, refer to the standard’s Document Summary page on the ASTM website.
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placed in a straight-line abrasion tester, adjacent to a similar section of a standard calibration panel. The two sections are scrubbed
simultaneously to produce essentially identical abrasion experiences, and the amount of erosion loss in each section determined
from the panel weights before and after scrubbing.
3.2 The scrub resistance on a dry-film basis is calculated as the percent ratio of the weight loss of the calibration panel to that of
the test panel. From that value, scrub resistance is calculated on the basis of both dry- and wet-film volume.
4. Significance and Use
4.1 Interior paint films often become soiled, especially near doorways, windows, and play areas, and frequently need to be cleaned
by scrubbing. This test method covers the determination of the relative resistance of paints to erosion when scrubbed.
4.2 The precision of scrub resistance measurements in absolute physical values, such as Test Methods D2486 cycles-to-
failure(cycles-to-failure or this test method, microlitres per 100 cycles,cycles), is poor due to the relatively large effect of subtle
and difficult-to-control variables in test conditions. The test method described herein minimizes this problem by using a standard
calibration panel as an integral part of each scrubbing operation and relating its weight loss to that of the paint film under test to
establish the latter’s scrub resistance.
NOTE 1—The numerical scrub resistance values obtained by this test method are of significance only in relation to the specific calibration panel types with
which the value is obtained. Thus, for example, a scrub resistance value of 83 with a Type X calibration panel would be reported as 83X.
4.3 Results obtained by this test method do not necessarily represent the scrub resistance that might be determined if the test film
is allowed to dry before testing appreciably longer than the seven-day period specified herein.
4.4 Results obtained by this test method do not necessarily relate to ease of soil or stain removal (also referred to as “cleanability”
or “cleansability”). To test for those characteristics use Test Methods D3450 and D4828.
FIG. 1 Alignment of Panels for Scrubbing
5. Apparatus and Materials
5.1 Straight-line Scrub Tester, set for 37 6 1 cycles per minute, having a minimum intrinsic stroke length of 255 mm (10 in.),
counter for recording the number of scrub cycles, base pan, glass support plate, “Lilly” frame, and C-clamps to hold down the
entire test assembly.
5.2 Sponge Holder, stainless steel construction, weight: 450450 g 6 10 g, approximate inside dimensions: 22 by 7522 mm by
7 3
75 mm by 95 mm ( ⁄8 in. by 33 in. by 3 ⁄4 in.).
4 3 3 3 3
5.3 Polyurethane Sponges, skin free, open-cell formation, density 0.0320.032 g ⁄cm to 0.040 g/cm (2(2 lb ⁄ft to 2.5 lb/ft ),
compression (25 % deflection) 4.8 kPa (0.7 psi), width and length 0.08 in. (2 mm) larger than the sponge holder with which it is
to be used, thickness such that when inserted into the sponge holder it protrudes about 55 mm to 6 mm (0.25 in.) beyond the skirt
(see Fig. 1).
Sponges, available from suppliers of scrub testers, cut to precise size for their respective holders.
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5.4 Abrasive Pad, 6-mm6 mm ( ⁄4-in.) in.) thick, cut to same size as the sponge with which it is to be used.
5.5 Film Caster, with horseshoe frame, clearance 175 μm (7 mils), film width approximately 135 mm (5 ⁄4 in.).
5.6 Black Plastic Panels, dimensions: 0.250.25 % 6 10 % by 165165 mm by 430 mm (0.01(0.01 % 6 10 % by 6.56.5 in. by 17
in.). Level and uniform dull black surface, impervious to and unaffected by water or aliphatic solvents, plasticizer-free, density
3 3
1.331.33 g ⁄cm 6 0.05 g/cm .
3 3
NOTE 2—With dark colored paints use white panels. These should be the same as the black except for color, and density: 1.411.41 g ⁄cm 6 0.05 g/cm .
5.7 Drawdown Plate, 6-mm6 mm ( ⁄4-in.) in.) thick, clear float glass, size adequate to be used as a base for drawdowns on the
specified scrub test panels.
7 8-10
5.8 Non-Abrasive Scrub Medium, standard wetting liquid. Formula and preparation instructions are as follows:
Formula—Parts by Weight
A
Water, reagent, Specification D1193, Type IV 89.6
Hydroxyethyl cellulose 2.0
Detergent 4.0
Trisodium phosphate, anhydrous 4.0
B
Acetic acid glacial 0.3
Preservative 0.1
100.0
A
Vary to achieve a final consistency of 165165 g to 220 g (75 (75 Krebs Units to 85 Krebs Units) with a Stormer viscometer in accordance with Test Method D562.
B
Vary to achieve a final pH from 9.5 to 10.0 in accordance with Test Method E70.
5.8.1 Slowly add the hydroxyethyl cellulose to the water while stirring mechanically. Stir until uniform and then slowly add 2 to
3 drops of 28 % ammonium hydroxide solution while mixing, and continue mixing until the solution turns clear. In the order
shown, add the other ingredients separately, stirring continuously. Be sure each item is uniformly dispersed before adding the next
one. Finally, add the preservative and adjust the pH with glacial acetic acid.
NOTE 3—When a referee test is made the medium should be freshly prepared, or from a previously unopened container that is no more than 1-year old.
5.9 Analytical Balance With Windshield Enclosure, reading to 0.1 mg and accurate to 1 mg.
1 1
5.10 Static Shield, a thin gagegauge metal plate, size 110110 mm by 165 mm (4 ⁄4 by in. by 6 ⁄2 in.), to be placed on the balance
pan when weighing. A satisfactory shield can be made from 0.1750.175 mm to 0.300 mm (7(7 mil to 12 mil) thick aluminum or
tinplate.
5.11 Oven, adjusted to 50 to 55°C (120 to 130°F).50 °C to 55 °C (120 °F to 130 °F).
5.12 Calibration Panels, prepared in advance using paints of suitable scrub resistance.
Abrasive pad—Scotch-Brite #7448 manufactured by The sole source of supply of the abrasive pad known to the committee at this time is 3M Company, 3M Center Bldg.,
St. Paul, MN 55144-1000 55144-1000. Scotch-Brite™ Hand Pad #7448 has been found satisfactory. Pads cut to the correct size are available from suppliers of scrub testers.
If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at a meeting
of the responsible technical committee, which you may attend.
Scrub Test Panels—Black: Form P121-10N and White: Form P122-10N, available from The Leneta Co., 15 Whitney Rd., Mahwah, NJ 07430, were used in the
round-robin for this method. Other charts that are in compliance with requirements stated in 5.6 may be used also.
Non-Abrasive Scrub Medium—Catalog Item SC-1 available from The Leneta Company is made in accordance with these requirements.
Hydroxyethyl cellulose having a molar substitution (MS) value from 1.8 to 2.5 and a 2 % solution viscosity in the range of 44004400 cps to 6500 cps.
Iso-octylphenoxy polyethoxyethanol detergent, such as Triton X-100 has been found satisfactory for this purpose.
1,3,5-triethyl hexahydro-sym-triazine (Vancide TH), obtainable from R. T. Vanderbilt Co., 30 Winfield St., Norwalk, CT 06855, has been found satisfactory. It is no
longer available. It recommended to use whatever preservative is commonly used within your company.
Calibration panels may be prepared by individual laboratories for internal use and for relating their results to those of associated laboratories. Suitably aged and
standardized calibration panels, having “poor,” “good,” and “very good” scrub resistance are available commercially from the Leneta Company. These are identified as Type
A, C, and D respectively. The scrub resistance of Type A has been found to be approximately 35 % of Type C, and Type C approximately 50 % of Type D.
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NOTE 4—The procedure for preparing calibration panels is the same as described in 6.1 and 6.2 for regular test panels, except that the panels shall be
aged sufficiently before use to ensure that the effect of additional ageing on their scrub resistance is negligible. A period of 6 months has been found
adequate. Earlier use requires that in a given test series all calibration panels be the same age.
5.13 Pycnometer, for example, “weight-per-gallon” cup.
6. Procedure
6.1 Stir the test paint well by hand. (Do not shake)
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