ASTM D3539-87(1996)
(Test Method)Standard Test Methods for Evaporation Rates of Volatile Liquids by Shell Thin-Film Evaporometer
Standard Test Methods for Evaporation Rates of Volatile Liquids by Shell Thin-Film Evaporometer
SCOPE
1.1 These test methods cover the determination of the rate of evaporation of volatile liquids of low viscosity using the Shell Thin-Film Evaporometer. The test methods have been applied to a wide range of volatile liquids, including paint, varnish, and lacquer solvents and thinners to various hydrocarbons and to insecticide spray-base oils.
1.2 The test methods for the determination of evaporation rate using the thin-film evaporometer are: Sections Method A 2.3 ---Manual Recording 5 to 11 Method B---Automatic Recording 12 to 17
1.3 The test methods are limited only by the viscosity of the volatile liquid which must be sufficiently low to permit the dispensing of an accurately measured specimen from a syringe.
1.4 This standard does not purport to address all of the safety problems, 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. Specific hazard statements are given in Notes 1 and 2.
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Standards Content (Sample)
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Designation: D 3539 – 87 (Reapproved 1996)
Standard Test Methods for
Evaporation Rates of Volatile Liquids by Shell Thin-Film
Evaporometer
This standard is issued under the fixed designation D 3539; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 3. Summary of Test Methods
1.1 These test methods cover the determination of the rate 3.1 A known volume of liquid is spread on a known area of
of evaporation of volatile liquids of low viscosity using the filter paper that is suspended from a sensitive balance in a
Shell thin-film evaporometer. These test methods have been cabinet. Dried air or nitrogen at 25°C is passed through the
applied to a wide range of volatile liquids, including paint, cabinet at a known rate. The loss of weight of the filter
varnish, and lacquer solvents and thinners to various hydrocar- paper/liquid is determined and plotted against time.
bons and to insecticide spray-base oils.
4. Significance and Use
1.2 The test methods for the determination of evaporation
4.1 The rate of evaporation of volatile liquids from a
rate using the thin-film evaporometer are:
solution or dispersion is important because it affects the rate of
Sections
2,3
Test Method A —Manual Recording 5-11
deposition of a film and flow during deposition, and thereby
Test Method B—Automatic Recording 12-17
controls the structure and appearance of the film. In the
1.3 These test methods are limited only by the viscosity of formulation of paints and related products, solvents are chosen
the volatile liquid which must be sufficiently low to permit the based on the evaporation characteristics appropriate to the
dispensing of an accurately measured specimen from a syringe. application technique and the curing temperature.
1.4 This standard does not purport to address all of the
TEST METHOD A—EVAPORATION RATE USING
safety concerns, if any, associated with its use. It is the
THE MANUAL THIN-FILM EVAPOROMETER
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
5. Apparatus
bility of regulatory limitations prior to use. Specific hazard
5.1 Evaporometer, thin-film evaporometer as shown in
statements are given in Note 1 and Note 2.
Fig. 1 (see Annex A1).
2. Referenced Documents 5.2 Constant-Temperature Cabinet for evaporometer.
2.1 ASTM Standards:
NOTE 1—Precaution: In instances with the solvents and other volatile
D 891 Test Methods for Specific Gravity of Liquid Indus- materials normally tested using this apparatus and under the conditions
specified in this test method, the concentration of solvent or other
trial Chemicals
flammable material being exhausted into the laboratory atmosphere will
E 1 Specification for ASTM Thermometers
be significantly below any concentration that could be hazardous, that is,
a lower flammable limit. However, it may be desirable to locate the
instrument and cabinet in a laboratory exhaust hood if the routine handling
These test methods are under the jurisdiction of ASTM Committee D-1 on Paint
of certain materials may present a hazard due to toxicity, extreme
and Related Coatings, Materials, and Applications and are the direct responsibility
volatility, or flammability.
of Subcommittee D01.24 on Physical Properties of Liquid Paints and Paint
Materials.
5.3 Interval Timer: Stopwatch or Electric Timer—A timer
Current edition approved May 29, 1987. Published July 1987. Originally
that gives an audible signal at 10 or 20-s intervals and that
published as D3539 – 76. Last previous edition D3539 – 76.
These test methods are essentially the same as the one developed by the New gives a warning signal approximately 3 s before the end of the
York Society for Paint Technology. The Precision section was added by ASTM
interval is preferred.
Subcommittee D01.24 and is based upon the data of the New York Society for Paint
Technology.
See “Comparative Evaporation Rates of Solvents: II,” New York Club,
Technical Subcommittee No. 66, Offıcial Digest, 28, No. 382, 1956, p. 1060.
Annual Book of ASTM Standards, Vol 15.05.
5 6
Annual Book of ASTM Standards, Vol 14.03. The manual Shell thin-film evaporometer is no longer available.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 3539
5.7 Hygrometer (or other humidity-sensing device), capable
of indicating low humidities.
5.8 Thermometers, of suitable accuracy such as ASTM
Bomb Calorimeter thermometer 56C having a range from 19 to
35°C, subdivisions 0.02°C or Thermometer 56F (66 to 95°F
with 0.05°F subdivisions), and conforming to the requirements
of Specification E 1.
6. Preparation of Evaporometer
6.1 Place the filter paper disk on the wire support, threading
the hook through a small hole in the center of the paper. Attach
the hook to the steel spring below the sighting disk and allow
the paper and the paper support to hang therefrom.
6.2 Close the evaporometer and cabinet doors and allow the
temperature in both chambers and the humidity to equilibrate at
the following test conditions:
FIG. 1 Details of the Thin-Film Evaporometer
Cabinet and evaporation temperature: 77 6 0.5°F (25 6 0.25°C)
Evaporometer humidity: 0 to 5 % relative humidity
5.4 Filter Paper Disk—Fast, open-textured filter paper, 90 Approximately 2 h are required for the humidity to drop to
mm in diameter, with a circle approximately 60 mm in less than 5 %.
diameter (and concentric with the edge) lightly drawn on the
6.3 Adjust the air flow to 21 L/min (center of ball float
paper with a pencil.
opposite correct mark on the rotometer scale).
5.5 Syringe—A 1.00-mL hypodermic syringe equipped with
a 225-mm needle of 1.3-mm outside diameter stainless steel
7. Conditioning
tubing. Due to manufacturing variations, the syringe should be
7.1 Bring the sample or a portion of it to an equilibrium
calibrated before use.
temperature of 77 6 1.0°F (25 6 0.5°C) in a constant-
5.6 Dehumidification Equipment—A suggested setup is
temperature bath. Determine the specific gravity of the sample
given in a schematic diagram, Fig. 2.
at this temperature in accordance with Test Methods D 891.
NOTE 2—Precaution: Use of this dehumidification apparatus requires
the safety practices relative to the handling, use, and disposal of hazardous
8. Procedure
acids and caustics be observed. When handling these materials, protective
8.1 Record the position of the filter paper as indicated by
eye or face shields, or both, and protective clothing are recommended.
NOTE 3—In those instances where dry nitrogen is available it may be alignment of the sighting disk with its mirror image. This is the
used directly instead of air and thus eliminate the dehumidification
no-load position.
equipment. The use of nitrogen does not alter the evaporation rate.
8.2 Raise the wire mesh bracket until the bottom of the disk
support rests lightly on it.
8.3 Withdraw into the syringe 0.70 mL of the solvent which
is at 77 6 1.0°F (25 6 0.5°C). Make certain that all air bubbles
Syringe: Becton, Dickinson and Co., No. 1YT available from Fisher Scientific
Co. Needle: Special Syringe Needle Type LNR, 18-gage, 9-in. long blunt round end, are expelled from the syringe and the needle before application
no bevel available on special order from Becton, Dickinson and Co. through Fisher
of the specimen to the filter paper.
Scientific Co., 711 Forbes Ave., Pittsburgh, PA 15239.
NOTE 1—One-litre flasks should be used throughout.
FIG. 2 Diagram of Dehumidification Apparatus
D 3539
8.4 Insert the hypodermic needle into the small opening on 10. Report
the right-hand side of the instrument and position the needle tip
10.1 Report the elapsed time in seconds at 10 weight %
so that it almost touches the disk and is just over the line that
intervals through 90 % and for 95 and 100 % evaporation, and
was drawn.
the relative evaporation rate (n-butyl acetate 5 1.0). Relative
8.5 Start applying the solvent to the disk. As the first drop
evaporation rate is calculated from the 90 weight % evaporated
hits the disk, start the timer. The solvent should be applied at a
times for the test solvent and for n-butyl acetate (99 % ester).
uniform rate in 62 s and as evenly as possible along the drawn
line. To ensure consistent specimen size, touch the tip of the
11. Precision
hypodermic needle to the filter paper to dispense the last drop
11.1 On the basis of an interlaboratory study of the test
of solvent.
method in which operators in six laboratories determined the
8.6 Immediately lower the wire mesh bracket away from the
90 % evaporation point of six solvents covering a broad range
disk support. Obtain the first reading of the position of the
in evaporation rate, the between-laboratories coeffi-cient of
sighting disk at 40 s and then every 20 s. Record the time and
variation was found to be 6.3 %relative at 24 df after discard-
the scale reading on the report form. A sample report form is
ing two divergent values. On the basis of the results obtained
shown in Annex A2.
by three laboratories on three of the solvents having 90 %
NOTE 4—With very slow evaporating solvents, it is not necessary to evaporated times of 200 to 600 s, the within-laboratory
take readings as often as every 20 s. The operator can determine a suitable
coefficient of variation was found to be 0.83 % relative at 18 df.
time interval after the first 200 s.
Based on these coefficients, the following criteria should be
used for judging the acceptability of results at the 95 %
8.7 Stop the timer when the sighting disk has returned to the
confidence level:
original unloaded position.
11.1.1 Repeatability—For solvents with 90 % evaporation
NOTE 5—The filter paper may be reused provided the solvent leaves no
times of 200 to 600 s, two results, each the mean of two
appreciable residue in evaporating.
determinations, obtained by the same operator on different
days should be considered suspect if they differ by more than
9. Calculation
2.5 %.
9.1 Calculate the evaporation rate as follows:
11.1.2 Reproducibility—Two results, each the mean of two
C
determinations, obtained by operators in different laboratories
ER 5 3 100~B 2 Z! (1)
S
should be considered suspect if they differ by more than
18.2 %.
where:
S 5 V 3 D and Z 5 N −(S/C)
TEST METHOD B—EVAPORATION RATE USING
ER 5 evaporation rate, wt %,
THIN-FILM EVAPOROMETER, AUTOMATIC
C 5 spring constant, g/cm elongation,
RECORDING
S 5 specimen weight,
V 5 0.70-mL aliquot volatile liquid at 77 6 1.0°F (25 6
12. Apparatus
0.5°C),
D 5 density of volatile liquid at 77 6 1.0°F (25 6 0.5°C)
12.1 Evaporometer, automatic thin-film evaporometer, as
(Taken as equivalent to specific gravity but with
shown in Fig. 3.
units of g/mL)
12.2 Filter Paper Disk—See 5.4.
B 5 scale reading taken during evaporation of aliquot,
12.3 Syringe—See 5.5.
Z 5 zero percent evaporated, scale reading 5 N−(S/C).
12.4 Dehumidification Equipment—See 5.6.
and
12.5 Strip Chart Recorder—Any strip chart recorder ca-
N 5 no-load scale reading (100 % evaporated reading).
pable of recording the output signal (0 to 15 mA) from the
9.2 Plot the percent evaporated against elapsed time in
electronic optical weight-sensing device. The recorder should
seconds and draw a smooth curve through the points. From the
provide a range of chart speeds including ⁄4 to 2 in. (6.3 to 50
curve, determine at 10 weight % increments to 90 % and for 95
mm)/min. It is also desirable for the recorder to accommodate
and 100 % evaporation the time in seconds to the nearest value
2 or more mA ranges in order to regulate the sensitivity of
as follows:
measurement.
Approximate Elapsed
Time to 100 % Report to Nearest
13. Preparation of Evaporometer
Evaporated Point, s Indicated Value, s
Less than 300 1
13.1 Place the filter paper disk on the wire frame threading
300 to 600 5
the hook through a small hole in the center of the paper. Attach
600 to 1800 10
the wire frame to the support hook in the evaporometer.
1800 to 3600 30
3600 to 7200 60
More than 7200 nearest 2 % of indicated value
NOTE 6—The curve drawn through the various points should pass
Supporting data are available from ASTM Headquarters. Request
through zero or the origin. If it passes to the right of the origin, the
RR:D01–1003.
delivery time was in excess of 12 s or an aliquot larger than that specified
The automatic Shell thin-film evaporometer, Apparatus Catalog No. F1522 is
was delivered. If it passes to the left of the origin, then the aliquot was
available from the Falex Corporation, Inc., 2055 Comprehensive Drive, Aurora, IL
smaller than specified. 60505.
D 3539
FIG. 3 Automatic Thin-Film Evaporometer
13.2 Close the evaporometer and cabinet doors and equili- specimen onto the filter paper. The complete specimen should
brate both chambers as in 6.2. be dispensed uniformly in 106 2 s along the line. The recorder
13.3 Adjust the air flow to 21 L/min.
pen will “advance” immediately to an “apex” position equiva-
lent to the total weight of the specimen, less that portion that
14. Conditioning of Sample
evaporated during the application period. The pen will gradu-
14.1 See 7.1.
ally return to its original position as the solvent evaporates and
the chart advances. The evaporation is complete when the
15. Procedure
recording pen has returned to its original “no-load” position.
15.1 When all components (including the filter paper in
NOTE 9—It is common for the final portion of the curve to exhibit a
place) are at equilibrium, adjust the recording pen to a
“tailing-off.” This is due to artifacts of the method such as (1) hydrogen
prominent “zero” position near the edge of the chart on the
bonding of the last traces of solvent with the cellulose fibers of the filter
recorder; then turn the switch for the chart motor to the OFF
paper and (2) a gradual diminution of the area of the filter paper wet by
position. This constitutes the “zero” load and time position for
solvent (that is, in the final stage of evaporation, drying of the paper
the test.
progresses from the outer edge toward the center of the disk). Thus, it is
common practice for the evaporation cycle to be considered “complete”
NOTE 7—The milliampere range and chart speed should be selected, if
when the recording pen returns to 99.5 % of the original displacement.
possible, so that the dimensions of the weight and time axes of the plotted
curve are approximately t
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