ASTM D3236-15(2021)
(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
5.1 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.
5.2 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.
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 × 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 D445 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D3236 − 15 (Reapproved 2021)
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 and Opaque Liquids (and Calculation of Dynamic Viscos-
ity)
1.1 This test method covers the determination of the appar-
ent viscosity of hot melt adhesives and coating materials
3. Terminology
compounded with additives and having apparent viscosities up
3.1 Definitions:
to 200 000 millipascal second (mPa·s) (Note 3) at temperatures
3.1.1 apparent viscosity, n—the viscosity determined by this
up to 175 °C (347 °F).
test method and expressed in millipascal seconds. Its value
NOTE 1—Although precision has not been studied, this procedure may
may vary with the spindle and rotational speed selected
be adaptable to viscosities higher than the present 200 000 mPa·s limit and
because many hot melts are non-Newtonian.
temperatures above 175 °C (347 °F). Equipment described in this test
method permits testing of materials having viscosities as high as
3.1.2 viscosity, n—the ratio of shear stress to shear rate. The
16 × 10 mPa·s and provides temperatures up to 260 °C (500 °F).
viscosity of a liquid is a measure of the internal friction of the
NOTE 2—For petroleum waxes and their blends having apparent
liquid in motion. The unit of dynamic viscosity is the pascal
viscosities below 15 mPa·s, Test Method D445 is especially applicable.
second. For a Newtonian liquid, the viscosity is constant at all
NOTE 3—One pascal second (Pa·s) = 1000 centipoise (cP); one milli-
shear rates. For a non-Newtonian liquid, viscosity will vary
pascal-second = one centipoise.
depending on shear rate.
1.2 The values stated in SI units are to be regarded as the
standard. The values in parentheses are for information only.
4. Summary of Test Method
1.3 This standard does not purport to address all of the
4.1 A representative sample of the molten material to be
safety concerns, if any, associated with its use. It is the
tested is maintained in a thermally controlled sample chamber.
responsibility of the user of this standard to establish appro-
Apparent viscosity is determined under temperature equilib-
priate safety, health, and environmental practices and deter-
rium conditions using a precision rotating spindle type viscom-
mine the applicability of regulatory limitations prior to use.
eter. Data obtained at several temperatures can be plotted on
1.4 This international standard was developed in accor-
appropriate semi-logarithmic graph paper and apparent viscos-
dance with internationally recognized principles on standard-
ity at intermediate temperatures can be estimated.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
5. Significance and Use
mendations issued by the World Trade Organization Technical
5.1 This test method distinguishes between hot melts having
Barriers to Trade (TBT) Committee.
different apparent viscosities. It is believed that apparent
viscosity determined by this procedure is related to flow
2. Referenced Documents
performance in application machinery operating under condi-
2.1 ASTM Standards:
tions of low shear rate. Apparent viscosity as determined by
D445 Test Method for Kinematic Viscosity of Transparent
this test method may not correlate well with end-use applica-
tions where high shear rates are encountered.
1 5.2 Materials of the type described in this procedure may be
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
quite non-Newtonian and as such, the apparent viscosity will
Subcommittee D02.10 on Properties of Petroleum Waxes and Alternative Wax-like
be a function of shear rate under the conditions of test.
Materials.
Although the viscometer described in this test method gener-
Current edition approved Jan. 1, 2021. Published February 2021. Originally
ally operates under conditions of relatively low shear rate,
approved in 1973. Last previous edition approved in 2015 as D3236 – 15. DOI:
10.1520/D3236-15R21.
differences in shear effect can exist depending upon the spindle
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and rotational speed conditions selected for the test program.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Maximum correlation between laboratories, therefore, depends
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. upon testing under conditions of equivalent shear.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3236 − 15 (2021)
6. Apparatus
6.1 Viscometer, Concentric Cylinder Rotational—The es-
sential instrumentation required providing the minimum ratio-
nal viscometer analytical capabilities include:
6.1.1 Drive motor, to apply a unidirectional rotational dis-
placement to the specimen at a rate of 0.5 r ⁄min to 60 r ⁄min
constant to 61 %.
6.1.2 Force sensor, to measure the torque developed by the
specimen in response to the rotational displacement.
6.1.3 Coupling shaft, or other means to transmit the rota-
tional displacement from the motor to the specimen.
NOTE 4—It is helpful to have a mark on the shaft to indicate appropriate
test fluid level.
6.1.4 Stainless steel rotational element, spindle, or tool, for
the type shown in Fig. 1 to fix the specimen between the draft
shaft and a stationary position.
6.1.5 Data collection device, to provide a means of
acquiring, storing, and displaying measured or calculated
signals, or both. The minimum output signals required for
rotational viscometry are torque, rotational speed, temperature,
and time.
NOTE 5—Manual observation and recording of data are acceptable.
6.1.6 Temperature measuring device, to provide an indica-
tion of the specimen temperature over their range of 100 °C to
200 °C to within 60.2 °C.
6.1.7 Stand, to support, level, and adjust the height of the
drive motor, shaft and rotational element.
6.1.8 Specimen container, fitted with an insulated cover, to
contain the test specimen during testing.
6.1.9 Auxiliary instrumentation considered necessary or
useful in conducting this method includes:
6.1.9.1 Data analysis capability to provide viscosity, stress,
or other useful parameters derived from measured signals.
6.1.9.2 Level to indicate the vertical plumb of the drive
motor, shaft, and rotational element.
6.1.9.3 A guard to protect the rotational element from
mechanical damage.
6.2 Temperature Bath and precision proportional tempera-
ture controller that provides a controlled isothermal tempera-
ture environment over the range of 100 °C to 200 °C (212 °F to
FIG. 1 Spindle Configuration
392 °F) constant to accuracy of 61.0 °C (1.8 °F).
6.3 Graph paper, semi-logarithmic.
shaft when the instrument, with or without the spindle in place,
7. Calibration is operated in air. When operating normally, the torque indica-
tion will be stable and have free oscillation about the zero point
7.1 The viscometer is precalibrated using Newtonian fluids
in air.
by the manufacturer. No zero adjustment is provided, since
experience has shown that the zero point will not vary due to 7.2 The instrument may be further calibrated using standard
changes in the torque sensor. The viscometer and spindles are reference fluids. Suitable fluids are available in nominal
precision equipment and should be kept from undue shock and viscosities up to 15 000 mPa·s at 149 °C (300 °F). The pro-
mishandling. Physical damage to the instrument will often cedure for instrument calibration using standard reference
reveal itself as erratic torque indication or no oscillation of the
The sole source of supply of the calibration fluids known to the committee at
The sole source of supply of the temperature controller known to the committee this time is Brookfield Engineering Laboratories, Inc., Stoughton, MA 02072 or
at this time is Athena Controls, Inc., 2 Union Rd., West Conshohocken, PA 19428. Cannon Instrument Co., P. O. Box 16, State College, PA 16801. If you are aware of
If you are aware of alternative suppliers, please provide this information to ASTM alternative suppliers, please provide this information to ASTM International
International Headquarters. Your comments will receive careful consideration at a Headquarters. Your comments will receive careful consideration at a meeting of the
1 1
meeting of the responsible technical committee, which you may attend. responsible technical committee, which you may attend.
D3236 − 15 (2021)
fluids is that encompassed by this test method. Results obtained 8.4.1 Ensure that the material in the sample chamber is
using standard reference fluids should not deviate from the completely molten and that the test specimen is equilibrated to
nominal viscosity by more than 2 %. the selected temperature controller settings.
8.4.2 Initiate the spindle rotation at the lowest spindle speed
7.3 To further check the controller and further establish
available to minimize temperature gradients in the sample as
controller settings, use the following procedure: Place a suffi-
well as possible shear effects.
cient quantity of low viscosity (500 mPa·s or less) hot melt in
8.4.3 When temperature equilibrium is indicated, stop the
the sample container to permit immersion of the appropriate
spindle rotation, remove the insulating cap, raise the viscom-
ASTM thermometer to the proper depth.
eter and spindle, and inspect the liquid level on the spindle
NOTE 6—Do not permit the temperature sensor to rest on the bottom of
shaft. It should extend about 3 mm ( ⁄8 in.) up the spindle shaft
the sample container.
beyond the upper, tapered portion of the spindle. If the liquid
level varies significantly f
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