ASTM D5682-08(2012)

Standard Test Methods for Electrical Resistivity of Liquid Paint and Related Materials

SIGNIFICANCE AND USE
4.1 These tests are suitable for testing paints adjusted for compatibility with various electrostatic spray coating applications, and by their use, spray performance can be optimized.
SCOPE
1.1 These test methods cover the determination of specific resistance (resistivity) of liquid paints, solvents, and other fluids in the range of 0.6 to 2640 MΩ-cm.  
1.2 Test Method A describes a procedure for making resistance tests with a commonly used paint application test assembly (Fig. 1 and Fig. 2).
FIG. 1 Analog Paint Application Test AssemblyFIG. 2 Diagram of Digital Application Test Assembly  
1.3 Test Method B describes a procedure for making resistance tests with a conductivity meter (Fig. 3).
FIG. 3 Conductivity Meter  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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.

General Information

• Status: Historical
• Publication Date: 31-Oct-2012
• ICS: 87.040 - Paints and varnishes
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.24 - Physical Properties of Liquid Paints & Paint Materials

Relations

• Replaces: ASTM D5682-08 - Standard Test Methods for Electrical Resistivity of Liquid Paint and Related Materials
• Effective Date: 01-Nov-2012

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D5682 − 08 (Reapproved 2012)
Standard Test Methods for
Electrical Resistivity of Liquid Paint and Related Materials
This standard is issued under the fixed designation D5682; 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* 3. Summary of Test Methods
1.1 These test methods cover the determination of specific 3.1 Test Methods A and B measure direct current through
resistance (resistivity) of liquid paints, solvents, and other concentric cylinder electrodes immersed in a liquid paint
fluids in the range of 0.6 to 2640 MΩ-cm. specimen.
1.2 Test Method A describes a procedure for making resis-
4. Significance and Use
tance tests with a commonly used paint application test
4.1 These tests are suitable for testing paints adjusted for
assembly (Fig. 1 and Fig. 2).
compatibility with various electrostatic spray coating
1.3 Test Method B describes a procedure for making resis-
applications, and by their use, spray performance can be
tance tests with a conductivity meter (Fig. 3).
optimized.
1.4 The values stated in SI units are to be regarded as
5. Interferences
standard. No other units of measurement are included in this
standard.
5.1 Contamination of the specimen is the most likely cause
1.5 This standard does not purport to address all of the of error. Very small amounts of water, acids, or polar solvents
safety concerns, if any, associated with its use. It is the will lower the resistance of high resistivity solvents and paints.
responsibility of the user of this standard to establish appro-
5.2 High humidity is not known to interfere with the test
priate safety and health practices and determine the applica-
itself but can lead to water pickup by the specimen. For
bility of regulatory limitations prior to use.
repeatable results, tests should be made under the same
atmospheric conditions and specimens should be stored and
2. Terminology
handled so as to keep water pickup to a minimum.
2.1 Definitions:
5.3 Resistivity varies with temperature. A standard test
2.1.1 specific resistance (resistivity), n—the ratio of the d-c
temperature of 25°C is recommended. Other temperatures are
potential gradient in volts per centimetre paralleling the current
possible on agreement between the producer and the user.
flow within the specimen to the current density in amperes per
square centimetre at a given instant of time and under
5.4 Electrification time must be the same for every test due
prescribed conditions.
to ion migrations that cause current flow to decrease with time.
2.1.1.1 Discussion—This is numerically equal to the resis-
Variations with time of electrification can result in appreciable
tancebetweenoppositefacesofacentimetrecubeoftheliquid.
variation in the test results.
The units are ohm centimetres (or megohm centimetres).
5.5 Devices described in Test Methods A and B apply
2.2 Definitions of Terms Specific to This Standard:
differenttestvoltages(45Vand15V,respectively).Becauseof
2.2.1 kilohm (KΩ), n—resistance value equal to 1000 Ω
this, some variation in results may be expected.
(10 ).
6. Reagents and Materials
2.2.2 megohm (MΩ), n—resistance value equal to 1 000 000
Ω (10 ). 6.1 Low Resistivity Cell Constant Standards (see Appendix
X1 for cell constant determination method).
2.2.3 ohm-centimetre (or megohm-centimetre), n—unit of
6.1.1 Potassium Chloride, 1000 µΩ/cm.
specific resistance (resistivity).
6.2 Cleaning Solvents and Solutions—It is essential to
These test methods are under the jurisdiction of ASTM Committee D01 on thoroughly clean the probe before and after tests. The cleaning
Paint and Related Coatings, Materials, and Applications and are the direct
solvent should be chosen on the basis of the paint tested. Due
responsibility of Subcommittee D01.24 on Physical Properties of Liquid Paints and
care must be exercised in cleaning to ensure all cleaning
Paint Materials.
Current edition approved Nov. 1, 2012. Published November 2012. Originally
approved in 1995. Last previous edition approved in 2008 as D5682 - 08. DOI:
10.1520/D5682-08R12. 1000 µΩ/cm test solutions are available from scientific supply companies.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5682 − 08 (2012)
FIG. 1 Analog Paint Application Test Assembly
FIG. 3 Conductivity Meter
8. Standardization
8.1 For maximum accuracy, the probe should be standard-
ized to determine the exact cell constant. For routine measure-
ments a cell constant (K) of 132 may be used (see Appendix
X1).
8.2 The electronic-resistance measuring assembly may be
checked by use of a standard-resistance decade box ( ⁄2 %
accuracy or better).
9. Procedure
FIG. 2 Diagram of Digital Application Test Assembly
9.1 Prior to tests, make sure that the probe is thoroughly
cleaned (see 6.2).
solvents are removed from the probe before reusing.The probe 9.2 Insert the paint test probe into the jack in the lower right
must be dry and free from contaminates or results will vary.
side of the meter case.
9.3 Set the scale select switch (top center) to the Scale B
position.
TEST METHOD A
9.4 Move the mode select switch (top right) to the Zero
7. Apparatus
Adjust position and rotate the zero adjust knob (top left) until
7.1 Paint Application Test Assembly—designed to provide the dial indicator needle centers on the adjust position (far
right).Maximumaccuracywillberealizedwiththemeterlying
measurement of the electrical resistance of paint formulations
for all electrostatic applications.To provide greater accuracy in flat, meter face up.
measuring low resistance paints, the meter is equipped with
NOTE 1—If the needle will not adjust to zero, replace the battery.
dual range selection. Range “A” is .005 to 1 MΩ , Range “B”
9.5 Move the mode select switch to the Paint Test position.
is .05 to 20 MΩ. The original version of this device was an
analog instrument with a pointer and scale as shown in Fig. 1 9.6 Immerse the probe vertically into a well-mixed, visually
and many such instruments are in use. It has been replaced by uniform specimen of the subject material until the holes at the
a digital version, a diagram of which is in Fig. 2. bottom of the slots in the probe sleeve are submerged.
D5682 − 08 (2012)
Warning—Do NOT immerse the probe past the top of 12.5 To convert the megohms readings to specific resistivity
sleeve. in megohm-centimetres, multiply by 132.5 cm.
9.7 Read the paint resistance from Scale B. If the reading is 12.6 Clean the probe thoroughly. Allow the apparatus and
less than 0.5 on the B scale, move the scale select switch to the specimen to stand for 1 h (keep lids of s
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