ASTM D3236-88(1999)

Standard Test Method for Apparent Viscosity of Hot Melt Adhesives and Coating Materials

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[dot]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[dot]s limit and temperatures above 175°C (347°F). Equipment described in this procedure permits testing of materials having viscosities as high as 16 X 10  mPa[dot]s and provides temperatures up to 260°C (500°F). Note 2-For petroleum waxes and their blends having apparent viscosities below 15 mPa[dot]s, Method D445 is especially applicable. Note 3-One pascal second (Pa[dot]s) = 1000 centipoise (CP); one millipascal second (mPa[dot]s) = one centipoise. %1.2 The values stated in acceptable metric 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 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.

General Information

• Status: Historical
• Publication Date: 09-Apr-1999
• ICS: 83.180 - Adhesives
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.10.0A - Physical/Chemical Properties

Relations

• Replaced By: ASTM D3236-88(2004) - Standard Test Method for Apparent Viscosity of Hot Melt Adhesives and Coating Materials
• Effective Date: 01-May-2004
• Referred By: ASTM D4730-13(2020) - Standard Specification for Flooding Compounds for Telecommunications Wire and Cable
• Effective Date: 10-Apr-1999

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
An American National Standard
Designation: D 3236 – 88 (Reapproved 1999)
Standard Test Method for
Apparent Viscosity of Hot Melt Adhesives and Coating
Materials
This standard is issued under the fixed designation D 3236; 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 (ϵ) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Terminology
1.1 This test method covers the determination of the appar- 3.1 Definitions:
ent viscosity of hot melt adhesives and coating materials 3.1.1 viscosity—the ratio of shear stress to shear rate. The
compounded with additives and having apparent viscosities up viscosity of a liquid is a measure of the internal friction of the
to 200 000 millipascal second (mPa·s) (Note 3) at tempera- liquid in motion. The unit of dynamic viscosity is the pascal
tures up to 175°C (347°F). second. For a Newtonian liquid, the viscosity is constant at all
shear rates. For a non-Newtonian liquid, viscosity will vary
NOTE 1—Although precision has not been studied, this procedure may
depending on shear rate.
be adaptable to viscosities higher than the present 200 000-mPa·s limit
3.1.2 apparent viscosity—the viscosity determined by this
and temperatures above 175°C (347°F). Equipment described in this
test method and expressed in millipascal seconds. Its value
procedure permits testing of materials having viscosities as high as
163 10 mPa·s and provides temperatures up to 260°C (500°F).
may vary with the spindle and rotational speed selected
NOTE 2—For petroleum waxes and their blends having apparent vis-
because many hot melts are non-Newtonian.
cosities below 15 mPa·s, Test Method D 445D 445 is especially appli-
cable.
4. Summary of Test Method
NOTE 3—One pascal second (Pa·s) = 1000 centipoise (CP); one milli-
4.1 A representative sample of the molten material to be
pascal second (mPa·s) = one centipoise.
tested is maintained in a thermally controlled sample chamber.
1.2 The values stated in acceptable metric units are to be
Apparent viscosity is determined under temperature equilib-
regarded as the standard. The values in parentheses are for
rium conditions using a precision rotating spindle type viscom-
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-
priate safety and health practices and determine the applica-
5. Significance and Use
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-
D 445 Test Method for Kinematic Viscosity of Transparent
tions of low shear rate. Apparent viscosity as determined by
and Opaque Liquids (the 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
quite non-Newtonian and as such the apparent viscosity will be
a function of shear rate under the conditions of test. Although
This test method is under the jurisdiction of ASTM Committee D-2 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
the viscometer described in this test method generally operates
D02.10.0A on Physical and Chemical Properties.
under conditions of relatively low shear rate, differences in
Current edition approved Oct. 31, 1988. Published December 1988. Originally
sheareffectcanexistdependinguponthespindleandrotational
published as D 3236 – 73. Last previous edition D 3236 – 73 (1983).
Annual Book of ASTM Standards, Vol 05.01. speed conditions selected for the test program. Maximum
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
D 3236 – 88 (1999)
NOTE 4—Particular care must be taken not to overflow the sample
correlation between laboratories, therefore, depends upon test-
chamber when using the 100°C, 76-mm immersion thermometer.
ing under conditions of equivalent shear.
5.3 Approximate shear rates using various spindles are
7.3.1 Insert the thermometer through the insulating cover of
shown in Table A1.1 in the Annex to this procedure.
the sample container and hold it in place at the point required
for proper immersion depth. Adjust the thermal controller to
6. Apparatus
provide the desired test temperature. Rotate the thermometer
during temperature reading to minimize the effect of thermal
6.1 Viscometer, rotating spindle type with leveling stand.
gradients in the sample. Continue temperature readings and
6.2 Viscometer Spindles, stainless steel.
controller adjustment until minimum deviation from test tem-
6.3 Sample Chamber, with precision proportional tempera-
,
3 4
ture controller that provides control accuracy of 61.0°C perature is obtained. Minimum deviation may vary between
laboratories, depending upon the controller, but should in no
(1.8°F) or better through the range from 100 to 200°C (212 to
392°F). case exceed60.5°C (0.9°F). Repeat this procedure for any test
temperature desired within the scope of this procedure.
6.4 Graph Paper, semi-logarithmic.
8. Procedure
7. Calibration
8.1 Selection of Spindle—From the estimated viscosity of
7.1 The viscometer is precalibrated using Newtonian fluids
the sample and Table A1.1 in the Annex, select a viscometer
by the manufacturer. No zero adjustment is provided since
and spindle combination that will produce readings in the
experience has shown that the zero point will not vary due to
desired range.
changes in the spring. The viscometer and spindles are preci-
sion equipment and should be kept from undue shock and
NOTE 5—Use only the spindle shown to be appropriate for the
mishandling. Physical damage to the instrument will often
viscometer to be used.
reveal itself as erratic or no oscillation of the pointer when the
8.1.1 Wheremorethanonespindleisavailablefortherange
instrument, with or without the spindle in place, is operated in
selected, choose the spindle that produces results nearest the
air. When operating normally, the pointer will be stable and
midpoint of the measurable viscosity range. Viscometer scale
have free oscillation about the zero point in air.
readings must be within the 10 to 95 range.
7.2 The instrument may be further calibrated using standard
reference fluids. Suitable fluids are available in nominal NOTE 6—Care must be taken in the storage and handling of spindles
and assemblies. Protect them from dust, corrosive deposits, and mechani-
viscosities up to 15 000 mPa·s at 149°C (300°F). The
cal abuse. Avoid touching the calibrated section of the spindle with the
procedure for instrument calibration using standard reference
hands. Clean the spindle and sample chamber thoroughly after each use.
fluidsisthatencompassedbythistestmethod.Resultsobtained
A recommended cleaning procedure is included in Annex A2.
using standard reference fluids should not deviate from the
8.2 Preparation of Sample—Place the required amount of
nominal viscosity by more than 2 %.
representative sample (see Table 2) measured to the nearest
7.3 The temperature controller of the type recommended for
0.005 g (or 0.05 mL if handled in the molten state) in the
this procedure is factory calibrated and has control capability
sample chamber. Melt the sample in an oven set at the desired
of 60.5 % of the control point (61.0°C at 175°C). To further
test temperature or in the thermo-container preheated to the
check the controller and further establish controller settings,
desired test temperature.Avoid excessive or prolonged heating
use the following procedure: Place a sufficient quantity of low
of the sample to minimize thermal and oxidative effects. Use a
viscosity (500 mPa·s or less) hot melt in the sample container
fresh sample for each temperature for which a determination is
to permit immersion of the appropriate ASTM thermometer to
to be made.
theproperdepth.Donotpermitthethermometerbulbtoreston
8.3 System Alignment and Spindle Insertion—After the
the bottom of the sample container. Suitable thermometers are
sample is completely melted, lower the properly aligned and
shown in Table 1.
leveled viscometer until the tips of the alignment bracket just
touch the top of the thermo-container, making contact directly
behind the locating ring. Raise the viscometer, positioning the
3 1
Suitable viscometers and accessories can be obtained from Brookfield Engi- tips of the alignment bracket 2 mm ( ⁄16 in.) above the top of
neering Laboratories, Inc., Stoughton, MA 02072.
A suitable temperature controller can be obtained from Athena Controls, Inc.,
2 Union Road, West Conshohocken, PA 19428.
TABLE 2 Sample Size Requirement
Suitable calibration fluids may be obtained from Brookfield Engineering
Approximate Approximate Sample
Laboratories, Inc., Stoughton, MA 02072 or Cannon Instrument Co., P. O. Box 16,
Spindle
A
Volume, mL Weight, g
State College, PA 16801.
SC 4-18 8.00 6.40
SC 4-21 8.00 6.40
TABLE 1 Suitable ASTM Thermometers
SC 4-27 10.50 8.40
Scale
SC 4-28 11.50 9.20
Immersion, ASTM Thermometer
Temperature Range Error, SC 4-29 13.00 10.40
mm Number
max
SC 4-31 10.00 8.00
SC 4-34 9.50 7.60
90°C to 170°C 51 0.2°C 35C-62
A
194°F to 338°F 51 0.5°F 35F-62 Based on typical molten specific gravity of 0.800. If the specific gravity of the
145°C to 205°C 76 0.4°C 100C-68
material to be tested varies greatly from this value, sample size must be adjusted
to ensure proper liquid level on the spindle shaft.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
D 3236 – 88 (1999)
the thermo-container. Using both hands, gently slide the cated, turn off the viscometer, remove the insulating cap, raise
thermo-container base until the tips of the alignment bracket the viscometer and spindle, and inspect the liquid level on the
just touch the locating ring. Do not forcibly displace the spindle shaft. It should extend about 3 mm ( ⁄8 in.) up the
alignment bracket (see Fig. 1). Screw the link coupling nut spindle shaft beyond the upper, tapered portion of the spindle.
onto the viscometer coupling nut (note left-hand thread). If the liquid level varies significantly from this, add or remove
Connect the coupling link to the spindle (and the coupling nut). sample to provide this level. Replace the insulating cap, and
Lower the spindle into the sample chamber and connect the allow the unit to reestablish temperature equilibrium with the
link coupling nut to the viscometer coupling nut, noting the spindle rotating at the lowest available speed. Continue spindle
left-hand thread. Pick up the insulating cap and place it over rotation for 15 min after apparent equilibrium. Increase the
the sample chamber (see Fig. 1). spindle speed to that required to produce a scale reading
8.4 Viscosity Determination—Ensurethatthematerialinthe nearest the midpoint of the scale, but in no case outside the 10
sample chamber is completely molten and that temperature to 95 unit range. Engage the pointer clutch and stop the
controllersettingsareproper.Turnontheviscometerandallow viscometer motor when the pointer is in view. Record the scale
the spindle to rotate at the lowest spindle speed available to reading. Restart the viscometer motor, and allow at least five
minimize temperature gradients in the sample as well as additional revolutions of the spindle. Engage the pointer clutch
possible shear effects. When temperature equilibrium is indi- and stop the viscometer motor with the pointer in view. Record
FIG. 1 Apparatus for Viscosity Determination
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
D 3236 – 88 (1999)
the second dial reading. Repeat the above operation until three rataus under constant operating conditions on identical test
consecutive scale readings are obtained which differ by no material would, in the normal and correct operation of the test
more than 0.5 unit. method, 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
temperature. 25.4 % of the mean of the two results. (2)
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 total
least three different temperatures. From the plot, determine the apparent
of four viscometer models (Models LVF, LVT, RVT, and HBT) and seven
viscosity at any temperature requested, within the range of test tempera-
different spindles, each appropriately tailored to the viscometer used. The
tures.
effect of shear rate was disregarded.
10. Report
11.1.3 A review of that portion of the data which can be
10.1 Report the apparent visc
...