ASTM D6442-99

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 6442 – 99
Standard Test Method for
Copper Release Rates of Antifouling Coating Systems in
Seawater
This standard is issued under the fixed designation D 6442; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope priate safety practices and to determine the applicability of
regulatory limits prior to use. For specific hazard statements,
1.1 This test method covers the laboratory determination of
see Section 7.
the rate at which copper is released from an antifouling coating
in synthetic seawater using graphite furnace atomic absorption
2. Referenced Documents
spectrophotometry (GF-AAS).
2.1 ASTM Standards:
1.2 The procedure contains the preparation steps for the
D 1005 Test Methods for Measurement of Dry-Film Thick-
leach rate determination of copper from antifouling paints
ness of Organic Coatings Using Micrometers
including apparatus, reagents, holding tank conditions, and
D 1141 Specification for Substitute Ocean Water
sampling point details. Analysis for the concentration of copper
D 1193 Specification for Reagent Water
in seawater requires the accurate determination of copper at the
low parts per billion (ppb) level. To detect and correct for
3. Summary of Test Method
reagent impurities, acceptable analytical precision standards
3.1 The candidate paint system is applied to cylindrical test
are necessary. Therefore, the limit of quantitation for the
specimens. The coated specimens are placed in a tank of
analytical method should be 6 ppb or less. The method of
synthetic seawater where the copper levels are kept below 100
choice for most commonly available instrument with the
μg/L by circulating the seawater through an absorbent filter and
greatest sensitivity would be GF-AAS. This procedure is
an activated carbon filter. At specified intervals, each specimen
written to include necessary steps to isolate the copper from
is placed in 1500 mL of seawater (see Section 9 for details) and
seawater, thereby increasing sensitivity and eliminating salts
rotated 60 r/min for 1 h (or less, see 9.8 for further explanation
that interfere with the use of atomic absorption techniques.
and instruction). The rate of copper release from the paint is
1.3 Other analytical methods may be utilized with appro-
determined by measuring copper concentrations of the seawa-
priate procedural changes, as needed, to accommodate selectd
ter in the individual measuring containers.
specific methods. Such methods must meet the limit of
3.2 Analysis of the seawater for copper is conducted by
quantition (6 ppb) as presented in Section 13
extracting the copper with a solid state absorbent, elution with
1.4 This test method has not yet been validated to reflect
10 % HNO , and measuring for copper using GF-AAS.
in-situ copper release rates for antifouling products and there-
fore should not, at present, be used in the process of generating
4. Significance and Use
environmental risk assessments. In-service release rates of
4.1 This test method is designed to provide a laboratory
antifouling (AF) coatings are expected to vary with natural
procedure to measure changes in the release rates of copper
variability in seawater chemistry, temperature, and hydrody-
that occur during a period of immersion under specified
namic regime.
conditions of constant temperature, pH, salinity, and low
1.5 The values stated in SI units are to be regarded as
copper concentrations in the surrounding seawater. Quantita-
standard. The inch-pound units given in parentheses are for
tive measurement of the release rate is necessary to help in
information only.
selection of materials, in providing quality control, and in
1.6 This standard does not purport to address all of the
understanding the performance mechanism.
safety concerns, if any, associated with its use. It is the
4.2 This test method serves only as a guide for character-
responsibility of the user of this standard to establish appro-
ization of the early release pattern as well as estimating the
This test method is under the jurisdiction of ASTM Committee D-1 on Paint
and Related Coatings, Materials, and Applications and is the direct responsibility of Annual Book of ASTM Standards, Vol 06.01.
Subcommittee D01.45 on Marine Coatings. Annual Book of ASTM Standards, Vol 11.02.
Current edition approved December 10, 1999. Published February 2000. Annual Book of ASTM Standards, Vol 11.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D6442–99
steady-state release of copper from antifouling coatings. Cop- so that a rotating device can be attached to rotate the cylinder
per release rates of antifouling paint systems in service can with the upper end of the cylinder above the level of the test
vary over the life of the coating system depending on the container immersion liquid to prevent entry of the immersion
formulation and the environment. Differences in berthing liquid into the test cylinder (see Appendix X2). It is advisable
locations, operating schedules, length of service, condition of to weight the cylinder by filling with water so that the unit does
paint film surface, temperature, pH, and salinity can affect not have buoyancy.
results. Results obtained may not reflect actual copper release
NOTE 1—When coating release rates are very high, it may be desirable
rates that will occur in service, but provide reliable compari- 2
to use a 5–cm band (100 cm ) paint area to avoid exceeding 200 μg/L of
sons of the release rate characteristics of different antifouling
copper in the measuring containers (see 9.8.1).
formulations.
5.6 Test Cylinder Rotating Device: The device shall be
capable of rotating the test cylinder in the release rate measur-
5. Apparatus
ing container at 60 6 5 r/min (0.2 6 0.02 m/s, velocity of test
5.1 Release Rate Measuring Container—A nominal 2-L
cylinder surface). No part of the device shall be immersed in
( ⁄2-gal.) polycarbonate container, approximately 13.5 cm (5.3
seawater.
in.) in diameter and 19 cm (7.5 in.) high, fitted with three
5.7 Sample Tubes: 60-mL capacity with screw closures (or
polycarbonate rods approximately 6 mm (nominal ⁄4 in.) in
disposable bottles, culture tubes, etc.) made of polycarbonate,
diameter to serve as baffles. Rods shall be evenly spaced on the
polypropylene or borosilicate glass.
inside circumference of the container to prevent swirling of the
5.8 Vortex Mixer,or Ultrasonic Bath.
water with the test cylinder during rotation. The rods will be
5.9 Dispensers: Automatic or repeating for reagents.
secured to the container walls using acetone or methylene
5.10 Pipets, Class A.
chloride, (see Appendix X2).
5.11 GF-AAS, with appropriate background correction and
5.2 Constant Temperature Control: A means of maintaining
optional automatic sampler.
the release rate measuring test containers at a temperature of 25
5.12 pH Meter, with a suitable electrode.
6 1°C during the spin cycle.
5.13 Appropriate Hydrometer or Salinometer.
5.3 Holding Tank: An inert plastic container of such dimen-
5.14 Appropriate Volumetric Flasks.
sions so as to permit immersion of four or more test cylinders;
5.15 Column Processing System.
must be equipped with a system to continuously circulate the
5.16 Vacuum Pump.
seawater in the tank through an absorbent filter and an
5.17 Disposable Polypropylene Syringes,60mL
activated carbon filter. Regenerate as outlined in Appendix X1.
5.18 Syringe Filters, 0.45 μm.
The rate of water flow and the size of the filter should be
selected to maintain copper concentrations below 100 μg/L.
6. Reagents and Materials
Suggested flow rates should be set to obtain 2 to 8 turnovers
6.1 Purity of Reagents—All reagents and cleaning agents
per hour.
are to be reagent grade or better.
5.4 The size and geometry of the tanks as well as the
6.2 Purity of Water—Distilled water conforming to Type II
positioning of the inflow and outflow ports for the water
of Specification D 1193.
circulation system should be selected to obtain a slow, rela-
6.3 Seawater: Artificial ocean water in accordance with
tively uniform flow of seawater past all test cylinders in the
Section 6 of Specification D 1141 or a proprietary equivalent
tank. Maintain the pH of the synthetic seawater between 7.9
with a salinity of 33 to 34 ppt and pH 7.9-81.
and 8.1 and salinity between 33 and 34 parts per thousand
6.4 Extraction Media: Ion exchange, 200 to 400 mesh
(ppt). The tank shall be provided with heaters to maintain the
analytical grade and ion exchange resin , 20 to 50 mesh
temperature at 256 1°C (77 6 2°F).
analytical grade.
5.5 Test Cylinders: Approximately 6.4 cm (nominal
6.5 Copper Standards: Prepare standards using a stock
2- ⁄2in.) outside diameter by 17.8 cm (nominal 7 in.) long
solution of copper (1,000 ppm atomic absorption standard) (see
polycarbonate pipe or equivalent polycarbonate cylindrical
Section 9).
shapes coated with a 10-cm (3.94 in.) band of antifouling paint
6.6 Nitric Acid (HNO ): High purity (grade).
around the exterior circumference of the test cylinder to
6.7 Hydrochloric Acid (HCl): 10 %, v/v, aqueous solution.
provide 200 cm of paint film that can be immersed and freely
6.8 Nitric Acid (HNO ): 10 % vv, aqueous solution.
rotated in the release rate measuring container (see Note 1). A
6.9 Sodium Hydroxide (NaOH): 1N.
top disc, fitted with a shaft of proper diameter for rotating
6.10 Deionized Water.
device, should be sealed to the cylinder. Seal the bottom of the
6.11 Magnesium Nitrate Hexahydrate
test cylinder with a polycarbonate disc using acetone, methyl-
(Mg(NO ) ·6H O): 99.999 %,
3 2 2
ene chloride or a polycarbonate cement so as to form a
6.12 AA Modifier Solution (1 % Pd).
watertight joint. Do not coat the lower 1 to 2 cm (0.39 to 0.79
in.) of the test cylinder. The test cylinder shall be of such height
7. Hazards
7.1 Warning:. Antifouling paints contain toxic materials
that could cause skin and eye irritation on contact and adverse
A filter cartridge, containing Chelex ion exchange resin, 20 to 50 mesh,
physiological effects if ingested or inhaled. See antifouling
sufficient in size to require regeneration only once a month or less frequently should
be used. coating supplier’s Material Safety Data Sheet.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D6442–99
7.2 In the preparation of test specimens and the application the exterior circumferential surface of the test cylinder).
of various types of paints, the use of appropriate protective
Identify each cylinder to agree with coating sample code or
clothing and equipment is required consistent with local, state,
designation.
and federal government regulations, and recognized industrial
9.3 Paints shall be manufactured a minimum of seven days
and technical standards. Spills, overspray, and unused material
prior to testing. Also, test paints shall not be allowed to age
should not be flushed down the drain, but should be disposed
beyond the manufacturer’s recommended shelf life. Provide
of as hazardous waste.
typical storage conditions during aging, that is, sealed in a
container commonly used for sale and held at 20 to 30°C.
8. Calibration and Standardization
9.4 Apply antifouling paint to the exterior circumferential
8.1 Pipete 5 mL of 1000 ppm copper standard into a 100-mL
surface of three replicate test cylinders to produce a continuous
volumetric flask, add 3 to 4 mL of nitric acid and dilute to
band of antifouling paint with an exposure surface of 200 cm
volume with deionized water (50 ppm). Pipete 2 mL of this
or alternative area and a dry film thickness as recommended by
solution into another 100-mL volumetric flask and dilute to
manufacturer. To ensure complete surface coverage, a finished
volume with 10 % HNO (1000 ppb). Pipete 1, 3, 5, 8 and 10
dry film coating of 100 μm (0.004 in.) minimum is recom-
mL of this solution into separate 100-mL volumetric flasks and
mended. Follow manufacturer’s instructions with respect to
dilute to volume with 10 % HNO (10, 30, 50, 80 and 100 ppb).
mixing and drying. At a minimum, mechanically shake until
8.2 Prepare a spike in seawater at appropriate levels, based
on expected copper concentration in the test tank. the paint appears homogeneous. Apply using a sponge paint
8.3 Operate the graphite furnace in accordance with the applicator or spray as recommended by the manufacturer. If the
manufacturer’s instructions. Modifications may be needed with
paint is marketed only in spray cans, then apply as a spray.
respect to drying, pre-ash, ashing and atomization time cycles After the final application, allow the paint to dry for 7 6 1 day
to achieve optimum results.
at 25 6 2°C. Include application method and coating thickness
8.4 At the beginning of each instrument run, analyse the
in report.
10 % HNO blank and standards in order to establish that the
9.5 Measure the initial dry film thickness using a suitable
response of the instrument is linear. Plot separate calibration
non-destructive procedure found in Test Method D 1005.
curves for each analysis of the standards (peak area (abs·sec)
Remove masking promptly after paint is dry. At the conclusion
versus copper concentration) and calculate the slope, intercept,
of the test, measure the film thickness again.
and correlation coefficient for each curve using least squares fit
9.6 After the drying period, place one or more sets of three
or another appropriate procedure.
replicate cylinders coated with a test paint, and one control
8.5 Analyze the following:
(unpainted) cylinder in a holding tank. The painted surface on
8.5.1 Seawater blank: Extract and analyze as specified for
the cylinders must be completely submerged. Cylinders must
the test samples, to establish baseline.
be stationary, and positioned so that seawater moving through
8.5.2 Spiked Seawater Samples: Extract and analyze as
the tank will flow around each cylinder.
specified for test samples to determine extraction efficiency.
Recovery must be 100 % 6 10 %.
9.7 Monitor the pH (using a pH meter with a suitable
8.5.3 If changing the graphite tube during a run is necessary,
electrode) and the temperature of the seawater in the holding
the blank and standards should be an
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