ASTM D3236-88(2004)
(Test Method)Standard Test Method for Apparent Viscosity of Hot Melt Adhesives and Coating Materials
Standard Test Method for Apparent Viscosity of Hot Melt Adhesives and Coating Materials
SIGNIFICANCE AND USE
This test method distinguishes between hot melts having different apparent viscosities. It is believed that apparent viscosity determined by this procedure is related to flow performance in application machinery operating under conditions of low shear rate. Apparent viscosity as determined by this test method may not correlate well with end-use applications where high shear rates are encountered.
Materials of the type described in this procedure may be quite non-Newtonian and as such, the apparent viscosity will be a function of shear rate under the conditions of test. Although the viscometer described in this test method generally operates under conditions of relatively low shear rate, differences in shear effect can exist depending upon the spindle and rotational speed conditions selected for the test program. Maximum correlation between laboratories, therefore, depends upon testing under conditions of equivalent shear.
Approximate shear rates using various spindles are shown in Table A1.1 in the Annex to this test method.
SCOPE
1.1 This test method covers the determination of the apparent viscosity of hot melt adhesives and coating materials compounded with additives and having apparent viscosities up to 200 000 millipascal second (mPa·s) (Note 3) at temperatures up to 175°C (347°F).
Note 1—Although precision has not been studied, this procedure may be adaptable to viscosities higher than the present 200 000-mPa·s limit and temperatures above 175°C (347°F). Equipment described in this test method permits testing of materials having viscosities as high as 16 x 106 mPa·s and provides temperatures up to 260°C (500°F).
Note 2—For petroleum waxes and their blends having apparent viscosities below 15 mPa·s, Test Method D 445 is especially applicable.
Note 3—One pascal second (Pa·s) = 1000 centipoise (CP); one millipascal second = one centipoise.
1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only.
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.
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D3236–88(Reapproved2004)
Standard Test Method for
Apparent Viscosity of Hot Melt Adhesives and Coating
Materials
This standard is issued under the fixed designation D3236; 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 3.1.1 apparent viscosity—the viscosity determined by this
test method and expressed in millipascal seconds. Its value
1.1 This test method covers the determination of the appar-
may vary with the spindle and rotational speed selected
ent viscosity of hot melt adhesives and coating materials
because many hot melts are non-Newtonian.
compounded with additives and having apparent viscosities up
3.1.2 viscosity—the ratio of shear stress to shear rate. The
to 200 000 millipascal second (mPa·s) (Note 3) at temperatures
viscosity of a liquid is a measure of the internal friction of the
up to 175°C (347°F).
liquid in motion. The unit of dynamic viscosity is the pascal
NOTE 1—Although precision has not been studied, this procedure may
second. For a Newtonian liquid, the viscosity is constant at all
beadaptabletoviscositieshigherthanthepresent200 000-mPa·slimitand
shear rates. For a non-Newtonian liquid, viscosity will vary
temperatures above 175°C (347°F). Equipment described in this test
6 depending on shear rate.
method permits testing of materials having viscosities as high as 16 3 10
mPa·s and provides temperatures up to 260°C (500°F).
4. Summary of Test Method
NOTE 2—For petroleum waxes and their blends having apparent vis-
cosities below 15 mPa·s, Test Method D445 is especially applicable. 4.1 A representative sample of the molten material to be
NOTE 3—One pascal second (Pa·s) = 1000 centipoise (CP); one milli-
tested is maintained in a thermally controlled sample chamber.
pascal second = one centipoise.
Apparent viscosity is determined under temperature equilib-
1.2 The values stated in SI units are to be regarded as the rium conditions using a precision rotating spindle type viscom-
standard. The values in parentheses are for information only. eter. Data obtained at several temperatures can be plotted on
1.3 This standard does not purport to address all of the appropriate semi-logarithmic graph paper and apparent viscos-
safety concerns, if any, associated with its use. It is the ity at intermediate temperatures can be estimated.
responsibility of the user of this standard to establish appro-
5. Significance and Use
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. 5.1 Thistestmethoddistinguishesbetweenhotmeltshaving
different apparent viscosities. It is believed that apparent
2. Referenced Documents
viscosity determined by this procedure is related to flow
2.1 ASTM Standards: performance in application machinery operating under condi-
D445 Test Method for Kinematic Viscosity of Transparent tions of low shear rate. Apparent viscosity as determined by
and Opaque Liquids (and Calculation of Dynamic Viscos- this test method may not correlate well with end-use applica-
ity) tions where high shear rates are encountered.
5.2 Materials of the type described in this procedure may be
3. Terminology
quite non-Newtonian and as such, the apparent viscosity will
3.1 Definitions: be a function of shear rate under the conditions of test.
Although the viscometer described in this test method gener-
ally operates under conditions of relatively low shear rate,
This test method is under the jurisdiction of ASTM Committee D02 on
differences in shear effect can exist depending upon the spindle
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
and rotational speed conditions selected for the test program.
D02.10 on Properties of Petroleum Wax.
Current edition approved May 1, 2004. Published June 2004. Originally
Maximum correlation between laboratories, therefore, depends
approved in 1973. Last previous edition approved in 1999 as D3236–88 (1999).
upon testing under conditions of equivalent shear.
DOI: 10.1520/D3236-88R04.
5.3 Approximate shear rates using various spindles are
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM shown in Table A1.1 in the Annex to this test method.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D3236–88 (2004)
TABLE 1 Suitable ASTM Thermometers
6. Apparatus
Scale
6.1 Viscometer, rotating spindle type with leveling stand.
Immersion, ASTM Thermometer
Temperature Range Error,
mm Number
6.2 Viscometer Spindles, stainless steel.
max
6.3 Sample Chamber, with precision proportional tempera-
90°C to 170°C 51 0.2°C 35C-62
,
3 4
ture controller that provides control accuracy of 61.0°C
194°F to 338°F 51 0.5°F 35F-62
145°C to 205°C 76 0.4°C 100C-68
(1.8°F) or better through the range from 100 to 200°C (212 to
392°F).
6.4 Graph Paper, semi-logarithmic.
during temperature reading to minimize the effect of thermal
7. Calibration
gradients in the sample. Continue temperature readings and
7.1 The viscometer is precalibrated using Newtonian fluids controller adjustment until minimum deviation from test tem-
by the manufacturer. No zero adjustment is provided, since perature is obtained. Minimum deviation may vary between
experience has shown that the zero point will not vary due to laboratories, depending upon the controller, but should in no
changes in the spring. The viscometer and spindles are preci- case exceed 60.5°C (0.9°F). Repeat this procedure for any test
sion equipment and should be kept from undue shock and temperature desired within the scope of this test method.
mishandling. Physical damage to the instrument will often
8. Procedure
reveal itself as erratic or no oscillation of the pointer when the
instrument, with or without the spindle in place, is operated in
8.1 Selection of Spindle—From the estimated viscosity of
air. When operating normally, the pointer will be stable and
the sample and Table A1.1 in the Annex, select a viscometer
have free oscillation about the zero point in air.
and spindle combination that will produce readings in the
7.2 The instrument may be further calibrated using standard
desired range.
reference fluids. Suitable fluids are available in nominal
NOTE 5—Use only the spindle shown to be appropriate for the
viscosities up to 15 000 mPa·s at 149°C (300°F). The proce-
viscometer to be used.
dure for instrument calibration using standard reference fluids
8.1.1 Wheremorethanonespindleisavailablefortherange
isthatencompassedbythistestmethod.Resultsobtainedusing
selected, choose the spindle that produces results nearest the
standard reference fluids should not deviate from the nominal
midpoint of the measurable viscosity range. Viscometer scale
viscosity by more than 2 %.
readings must be within the 10 to 95 range.
7.3 The temperature controller of the type recommended for
this procedure is factory calibrated and has control capability
NOTE 6—Care must be taken in the storage and handling of spindles
of 60.5 % of the control point (61.0°C at 175°C). To further and assemblies. Protect them from dust, corrosive deposits, and mechani-
cal abuse. Avoid touching the calibrated section of the spindle with the
check the controller and further establish controller settings,
hands. Clean the spindle and sample chamber thoroughly after each use.
use the following procedure: Place a sufficient quantity of low
A recommended cleaning procedure is included in Annex A2.
viscosity (500 mPa·s or less) hot melt in the sample container
8.2 Preparation of Sample—Place the required amount of
to permit immersion of the appropriateASTM thermometer to
representative sample (see Table 2) measured to the nearest
theproperdepth.Donotpermitthethermometerbulbtoreston
0.005 g (or 0.05 mL if handled in the molten state) in the
the bottom of the sample container. Suitable thermometers are
sample chamber. Melt the sample in an oven set at the desired
shown in Table 1.
test temperature or in the thermo-container preheated to the
NOTE 4—Particular care must be taken not to overflow the sample
desired test temperature.Avoid excessive or prolonged heating
chamber when using the 100°C, 76-mm immersion thermometer.
of the sample to minimize thermal and oxidative effects. Use a
7.3.1 Insert the thermometer through the insulating cover of
fresh sample for each temperature for which a determination is
the sample container and hold it in place at the point required
to be made.
for proper immersion depth. Adjust the thermal controller to
8.3 System Alignment and Spindle Insertion—After the
provide the desired test temperature. Rotate the thermometer
sample is completely melted, lower the properly aligned and
leveled viscometer until the tips of the alignment bracket just
touch the top of the thermo-container, making contact directly
The sole source of supply of the viscometers and accessories known to the
committee at this time is Brookfield Engineering Laboratories, Inc., Stoughton, MA
02072. If you are aware of alternative suppliers, please provide this information to
TABLE 2 Sample Size Requirement
ASTM International Headquarters. Your comments will receive careful consider-
Approximate Approximate Sample
ation at a meeting of the responsible technical committee , which you may attend.
Spindle
A
Volume, mL Weight, g
Thesolesourceofsupplyofthetemperaturecontrollerknowntothecommittee
at this time isAthena Controls, Inc., 2 Union Road,West Conshohocken, PA19428. SC 4-18 8.00 6.40
If you are aware of alternative suppliers, please provide this information to ASTM SC 4-21 8.00 6.40
SC 4-27 10.50 8.40
International Headquarters. Your comments will receive careful consideration at a
SC 4-28 11.50 9.20
meeting of the responsible technical committee , which you may attend.
SC 4-29 13.00 10.40
The sole source of supply of the calibration fluids known to the committee at
SC 4-31 10.00 8.00
this time is Brookfield Engineering Laboratories, Inc., Stoughton, MA 02072 or
SC 4-34 9.50 7.60
Cannon Instrument Co., P. O. Box 16, State College, PA16801. If you are aware of
A
alternative suppliers, please provide this information to ASTM International
Based on typical molten specific gravity of 0.800. If the specific gravity of the
Headquarters.Your comments will receive careful consideration at a meeting of the
material to be tested varies greatly from this value, sample size must be adjusted
responsible technical committee , which you may attend. to ensure proper liquid level on the spindle shaft.
D3236–88 (2004)
behind the locating ring. Raise the viscometer, positioning the possible shear effects. When temperature equilibrium is indi-
tips of the alignment bracket 2 mm ( ⁄16 in.) above the top of cated, turn off the viscometer, remove the insulating cap, raise
the thermo-container. Using both hands, gently slide the the viscometer and spindle, and inspect the liquid level on the
thermo-container base until the tips of the alignment bracket spindle shaft. It should extend about 3 mm ( ⁄8 in.) up the
just touch the locating ring. Do not forcibly displace the spindle shaft beyond the upper, tapered portion of the spindle.
alignment bracket (see Fig. 1). Screw the link coupling nut If the liquid level varies significantly from this, add or remove
onto the viscometer coupling nut (note left-hand thread). sample to provide this level. Replace the insulating cap, and
Connectthecouplinglinktothespindle(andthecouplingnut). allow the unit to reestablish temperature equilibrium with the
Lower the spindle into the sample chamber and connect the spindle rotating at the lowest available speed. Continue spindle
link coupling nut to the viscometer coupling nut, noting the rotation for 15 min after apparent equilibrium. Increase the
left-hand thread. Pick up the insulating cap and place it over spindle speed to that required to produce a scale reading
the sample chamber (see Fig. 1). nearest the midpoint of the scale, but in no case outside the 10
8.4 Viscosity Determination—Ensurethatthematerialinthe to 95-unit range. Engage the pointer clutch and stop the
sample chamber is completely molten and that temperature viscometer motor when the pointer is in view. Record the scale
controllersettingsareproper.Turnontheviscometerandallow reading. Restart the viscometer motor, and allow at least five
the spindle to rotate at the lowest spindle speed available to additional revolutions of the spindle. Engage the pointer clutch
minimize temperature gradients in the sample as well as and stop the viscometer motor with the pointer in view. Record
FIG. 1 Apparatus for Viscosity Determination
D3236–88 (2004)
the second dial reading. Repeat the above operation until three under constant operating conditions on identical test material
consecutive scale readings are obtained that differ by no more would, in the normal and correct operation of the test method,
than 0.5 unit. exceed the following values in one case in twenty:
8.8 % of the mean of the two results. (1)
9. Calculation
11.1.2 Reproducibility—The difference between two single
9.1 Determine the average of the three consecutive scale
and independent results obtained by different operators work-
readings which differ by no more than 0.5 scale unit. To
ing in different laboratories in identical test material would, in
convert to millipascal seconds, multiply this value by the
the long run, exceed the following value only in one case in
appropriate factor taken from either the instrument instruction
twenty:
manual or Table A1.2 in the Annex. Repeat this for each
25.4 % of the mean of the two results. (2)
temperature.
NOTE 9—The precision of this test method is based on a round-robin
NOTE 7—If it is necessary to interpolate for viscosity values at
conducted using six wax-based hot melt materials that are believed to be
intermediate temperatures, plot a series of observed apparent viscosity
representative of the class. Tests were conducted at three temperatures by
valuesonthelogarithmicscaleandthecorrespondingtesttemperatureson
seven to eleven laboratories using the Brookfield viscometer model and
the linear scale of appropriate semi-logarithmic paper, using a series of at
spindle combination available to that laboratory.This encompassed a tot
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