ASTM D4584-05

Standard Test Method for Measuring Apparent pH of Electrocoat Baths

SIGNIFICANCE AND USE
The pH is the measure of the free hydrogen ion concentration of a sample, and it indicates whether an electrocoat bath is acidic, neutral, or basic. Since pH measurements of good precision are made in aqueous solutions, it is suggested that the pH measurements of electrocoat baths are only semi-quantitative, and therefore such measurements should be referred to as apparent pH measurements.
The pH of electrocoat paints is used for research, production, and quality control or electrocoat bath process control.
Other related methods for determining the pH of water or aqueous systems are described in Test Methods D 1293 and E 70.
SCOPE
1.1 This test method covers the measurement of the free hydrogen ion concentration of electrocoat baths and their ultrafiltrates.
1.2 &si-value;
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-Dec-2004
• ICS: 25.220.40 - Metallic coatings
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.21 - Chemical Analysis of Paints and Paint Materials

Relations

• Replaces: ASTM D4584-86(1999) - Standard Test Method for Measuring Apparent pH of Electrocoat Baths
• Effective Date: 01-Jan-2005
• Replaced By: ASTM D4584-05(2010) - Standard Test Method for Measuring Apparent pH of Electrocoat Baths
• Effective Date: 01-Jun-2010
• Referred By: ASTM D1978-91(2018) - Standard Guide for Analysis of Electrocoat Bath Samples
• Effective Date: 01-Jan-2005

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:D4584–05
Standard Test Method for
1
Measuring Apparent pH of Electrocoat Baths
This standard is issued under the fixed designation D4584; 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 that the pH measurements of electrocoat baths are only
semi-quantitative, and therefore such measurements should be
1.1 This test method covers the measurement of the free
referred to as apparent pH measurements.
hydrogen ion concentration of electrocoat baths and their
4.2 The pH of electrocoat paints is used for research,
ultrafiltrates.
production, and quality control or electrocoat bath process
1.2 The values stated in SI units are to be regarded as the
control.
standard. The values given in parentheses are for information
4.3 Other related methods for determining the pH of water
only.
or aqueous systems are described in Test Methods D1293 and
1.3 This standard does not purport to address all of the
E70.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5. Apparatus
priate safety and health practices and determine the applica-
5.1 pH Meter,
bility of regulatory limitations prior to use.
5.2 Glass and Reference Electrodes.
2. Referenced Documents
NOTE 1—Due to the polarity of electrocoat materials it is desirable to
2
2.1 ASTM Standards:
useaseparatesetofelectrodesforeachbathpolarity,cathodicandanodic,
because a bath of opposite polarity poisons the electrodes. A desired
D1193 Specification for Reagent Water
practice is to rinse the electrodes after each measurement with an
D1293 Test Methods for pH of Water
appropriate solvent for the electrocoat material.
E70 Test Method for pH of Aqueous Solutions With the
Glass Electrode 5.3 Thermometer, capable of 0.5°C accuracy with a−2 to
32°C range.
E180 Practice for Determining the Precision of ASTM
Methods for Analysis and Testing of Industrial and Spe-
6. Reagents
cialty Chemicals
6.1 Reference Standard Solutions, commercial standards of
3. Summary of Test Method
pH 4.0, 7.0, and 10.0.
3.1 Aspecimen of a well-agitated electrocoat bath is placed 6.2 Purity of Water—References to water shall be under-
stood to mean water conforming to Type II of Specification
in a stirrer-equipped container and the pH measured with a pH
meter and associated glass and reference electrodes. D1193.
7. Sampling and Sample Preparation
4. Significance and Use
4.1 The pH is the measure of the free hydrogen ion 7.1 The sample should be obtained while the electrocoat
bath is under proper circulation so that a uniform material is
concentration of a sample, and it indicates whether an electro-
coatbathisacidic,neutral,orbasic.SincepHmeasurementsof obtained. In case of an ultrafiltrate, the material should be
thoroughly mixed or stirred prior to sampling to assure
good precision are made in aqueous solutions, it is suggested
uniformity.
7.2 After sampling and prior to removing a test specimen it
1
This test method is under the jurisdiction of ASTM Committee D01 on Paint
is mandatory that the sample be shaken or stirred until it is
and Related Coatings, Materials, andApplications and is the direct responsibility of
homogeneous and free of any settled material. This is particu-
Subcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.
Current edition approved Jan. 1, 2005. Published February 2005. Originally
larly important if there is any delay between the sampling of
approved in 1986. Last previous edition approved in 1999 as D4584-86(1999).
the bath and the preparation of the specimens for the test. The
DOI: 10.1520/D4584-05.
2 absence of settled material can be ascertained visually (in a
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
transparent container) or by inserting a spatula, scraping the
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
bottom of the container to make sure that there is no settled
the ASTM website.
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D4584–05
matter. Shake or stir the samples until specimens are taken for should show drifts of less than 0.1 units/min. If these drift
measurement; this point is very important. limits are not met, check the pH meter and repeat the whole
procedure.
8. Procedure
9. Precision and Bias
8.1 Standardization—Turn on the pH meter and allow it to
9.1 In an interlaboratory study of the t
...