ASTM D4370-01(2012)

Standard Test Methods for Acid and Base Milliequivalent Content of Electrocoat Bath

SIGNIFICANCE AND USE
4.1 The acid and base concentrations are a measurement of the titratable acidic and alkaline components in the electrocoat baths. These measurements are used for research, production or electrocoat bath process control.
SCOPE
1.1 These test methods cover the determination of acid and base milliequivalent contents of anodic and cathodic electrocoat baths and their ultrafiltrates.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
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 health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 31-May-2012
• 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 D4370-01(2006) - Standard Test Methods for Acid and Base Milliequivalent Content of Electrocoat Bath
• Effective Date: 01-Jun-2012
• Referred By: ASTM D1978-91(2018) - Standard Guide for Analysis of Electrocoat Bath Samples
• Effective Date: 01-Jun-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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D4370 − 01 (Reapproved 2012)
Standard Test Methods for
Acid and Base Milliequivalent Content of Electrocoat Bath
This standard is issued under the fixed designation D4370; 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 5.2 Analytical Balance, with sensitivity of 0.1 mg.
1.1 These test methods cover the determination of acid and 5.3 pH Meter, any model.
base milliequivalent contents of anodic and cathodic electro-
5.4 Glass and Saturated Calomel Electrodes.
coat baths and their ultrafiltrates.
5.5 Syringes, 5-mL disposable.
1.2 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
6. Reagents
standard.
6.1 Purity of Reagents—Reagent grade chemicals shall be
1.3 This standard does not purport to address all of the
used in all tests. Unless otherwise indicated, it is intended that
safety concerns, if any, associated with its use. It is the
all reagents shall conform to the specifications of the Commit-
responsibility of the user of this standard to establish appro-
tee onAnalytical Reagents of theAmerican Chemical Society,
priate safety and health practices and determine the applica-
where such specifications are available.
bility of regulatory limitations prior to use.
Other grades may be used, provided it is ascertained that the
2. Referenced Documents reagent is of sufficiently high purity to permit its use without
lessening the accuracy of the determination.
2.1 ASTM Standards:
D1193 Specification for Reagent Water 6.2 Purity of Water—References to water shall be under-
stood to mean water conforming to Type II of Specification
3. Summary of Test Methods
D1193.
3.1 Specimens are titrated with standard acid and alkali
6.3 Potassium Hydroxide Solution in Methanol, 0.1
solutions respectively. Alternative procedures are given for
N—Preparebydissolving5.6gofpotassiumhydroxide(KOH)
determining acid and base concentrations potentiometrically or
pellets in 1 L of methanol. Standardize against NIST standard
using a pH meter.
reference material of acid potassium phthalate No. 84 using an
automatic potentiometric titrator to a given end point or,
4. Significance and Use
alternatively, to a phenolphthalein end point.
4.1 The acid and base concentrations are a measurement of
6.4 Hydrochloric Acid Solution , 0.1 N—Prepare by mixing
the titratable acidic and alkaline components in the electrocoat
about 8.50 mL of concentrated hydrochloric acid (HCl) (1.19
baths.Thesemeasurementsareusedforresearch,productionor
sp gr) into a mixture of 600 mL water and 400 mL methanol.
electrocoat bath process control.
Standardize against 0.1 N potassium hydroxide solution (see
6.3).
5. Apparatus
6.5 1,3-Propanediol (Propylene Glycol) (PG).
5.1 Automatic Potentiometric Titrator with Stirrer and
Recorder, any model.
6.6 Tetrahydrofuran (THF).
6.7 Reference pH Standard Solutions—Commercial stan-
dards of pH 4.0, 7.0, and 10.0.
These test methods are under the jurisdiction of ASTM Committee D01 on
Paint and Related Coatings, Materials, and Applications and are the direct
responsibility of Subcommittee D01.21 on Chemical Analysis of Paints and Paint
Materials.
CurrenteditionapprovedJune1,2012.PublishedJuly2012.Originallyapproved Reagent Chemicals, American Chemical Society Specifications, American
in 1984. Last previous edition approved in 2006 as D4370 – 01 (2006). DOI: Chemical Society, Washington, DC. For suggestions on the testing of reagents not
10.1520/D4370-01R12. listed by the American Chemical Society, see Analar Standards for Laboratory
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
Standards volume information, refer to the standard’s Document Summary page on MD.
the ASTM website. Svehla, G., Automatic Potentiometric Titration, Pergamon Press, 1978, p. 187.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4370 − 01 (2012)
7. Sampling and Sample Preparation
7.1 The sample should be obtained while the electrocoat
bath is under proper circulation such that a uniform material is
obtained. In case of an ultrafiltrate, the material should be
thoroughly mixed or stirred prior to sampling to assure
uniformity.
7.2 After sampling and prior to removing a test specimen, it
ismandatorythatthesamplesbeshakenorstirreduntiltheyare
homogeneous and free of any settled material. This is particu-
larly important if there is a delay between sampling the bath
and performing the test. The absence of settled material can be
ascertained visually (in a transparent container) or by inserting
a spatula, scraping the bottom of the container, and making
sure that there is no settled matter. The shaking or stirring of
(a) Acid Milliequivalent Content Titration
the samples should be carried out up to the moment of taking
a specimen; this Point is Very Important.
8. Base Concentration Content
8.1 Stir the sample very thoroughly to disperse materials
that might have settled to the bottom of the container. With the
aid of a syringe, withdraw approximately 5 mL of the sample
quickly, weigh the full syringe to 0.1 mg, and record this
weight as W . Transfer the entire contents of the syringe into a
100-mL beaker. Reweigh the empty syringe to 0.1 mg and
record as W . Duplicate the procedure using a second speci-
men.
8.2 Add approximately 40 mL of THF/PG 80/20 mixture to
the specimens in the beakers and cover, preferably with
aluminum foil, to minimize evaporation of the solvent mixture.
...