ASTM D3795-00a(2006)
(Test Method)Standard Test Method for Thermal Flow, Cure, and Behavior Properties of Pourable Thermosetting Materials by Torque Rheometer
Standard Test Method for Thermal Flow, Cure, and Behavior Properties of Pourable Thermosetting Materials by Torque Rheometer
SIGNIFICANCE AND USE
The continuous recording of torque and temperature while going through these various stages can be used to predict the behavior of the material during processing.
The torque rheometer test has two important functions. First, it is a means to predict flow/viscosity and cure characteristics of pourable thermosetting compounds. For example, the test provides useful data to predict the processibility of a material in a particular molding method. This information is also useful to optimize process conditions for a particular material such as the minimum pressure to fill a mold and the time to cure a part. A second capability of the test is to provide a graphic record of the batch-to-batch uniformity of the molding compound.
SCOPE
1.1 This test method covers the apparatus, and a specific test method, including the evaluation of results required for the determination of the thermal flow and cure behavior properties of pourable thermosetting materials.
1.2 This test method can be used:
1.2.1 As a control for the development and production of pourable thermosetting materials and to measure the different properties (for example, melting behavior, cure behavior, etc.) as well as the influence of various additives and fillers in any given formulations, and
1.2.2 Verify the uniformity of different production batches of the same formulation.
1.3 The values are stated in SI units.
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. Specific precautions are given in Section 7.Note 1
There is no similar or equivalent ISO standard.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D3795 − 00a(Reapproved 2006)
Standard Test Method for
Thermal Flow, Cure, and Behavior Properties of Pourable
Thermosetting Materials by Torque Rheometer
This standard is issued under the fixed designation D3795; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* 3. Terminology
1.1 Thistestmethodcoverstheapparatus,andaspecifictest 3.1 Definitions of Terms Specific to This Standard:
method, including the evaluation of results required for the
3.1.1 For the purpose of this test method, the following
determination of the thermal flow and cure behavior properties
definitions apply, (see Fig. 1):
of pourable thermosetting materials.
3.1.2 flow and cure behavior—the flow behavior is repre-
sented by the recorded torque curve from the loading peak
1.2 This test method can be used:
(Point t ), to the torque minimum (Point t ).The cure behavior
1 5
1.2.1 As a control for the development and production of
is represented by the recorded torque curve from the torque
pourable thermosetting materials and to measure the different
minimum(Point t )tothetorquemaximum(Point t ).Therate
5 4
properties (for example, melting behavior, cure behavior, etc.)
of curing is represented by the slope of the torque curve.
as well as the influence of various additives and fillers in any
given formulations, and
3.1.3 time—the residence time at torque t × X, where X is
1.2.2 Verify the uniformity of different production batches
a factor (preferably 1.3) is t (s). To determine t , draw a line
v v
of the same formulation.
att × Xparallelwiththetimeaxis.Theintersectionofthisline
with the left branch of the curve is t . The intersection of this
1.3 The values are stated in SI units.
line with the right branch of the curve is t :
1.4 This standard does not purport to address all of the
t 5 t 2 t unitsareseconds ~s! (1)
safety concerns, if any, associated with its use. It is the v 3 2
3.1.3.1 Discussion—Depending on the manufacturer of the
responsibility of the user of this standard to establish appro-
equipment, the software analysis program for the designated
priate safety and health practices and determine the applica-
values in this test method may differ (t , t , etc.).
bility of regulatory limitations prior to use. Specific precau- 1 2
3.1.3.2 Discussion—Upon agreement between interested
tions are given in Section 7.
parties, the value of X may be changed and be listed in any
NOTE 1—There is no similar or equivalent ISO standard.
report.
2. Referenced Documents
3.1.4 residencetimeordurationofplasticlife(t −t )—the
2 3
residence time is represented by a section of the recorded
2.1 ASTM Standards:
torque curve in which the molten material causes the lowest
D792Test Methods for Density and Specific Gravity (Rela-
torque, s.
tive Density) of Plastics by Displacement
D883Terminology Relating to Plastics
3.1.5 totalcuretime(t −t )—timefromwhenthematerial
4 0
D1898Practice for Sampling of Plastics (Withdrawn 1998)
is loaded into the mixer chamber up to complete cure, s.
E691Practice for Conducting an Interlaboratory Study to
3.1.6 torque:
Determine the Precision of a Test Method
3.1.6.1 initial torque (t )—the initial high torque peak once
material is loaded into the mixer chamber. Sometimes referred
ThistestmethodisunderthejurisdictionofASTMCommitteeD20onPlastics
to as the loading peak, Nm (Newton-meters).
and is the direct responsibility of Subcommittee D20.30 on Thermal Proper-
3.1.6.2 minimum torque (t )—the lowest point on the torque
ties.30.08).
curve representing maximum fluxing of material, Nm.
Current edition approved March 15, 2006. Published April 2006. Originally
approved in 1979. Last previous edition approved in 2000 as D3795–00a. DOI:
3.1.6.3 final torque or cure peak (t )—the final maximum
10.1520/D3795-00AR06.
torque value representing the final cure of material, Nm.
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
4. Summary of Test Method
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
4.1 A sample of thermosetting material is charged into the
The last approved version of this historical standard is referenced on
www.astm.org. temperature controlled mixer/measuring head in which the
*A Summary of Changes section appears at the end of this standard
Copyright ©ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA19428-2959. United States
D3795 − 00a (2006)
NOTE 2—Only the results obtained with identical measuring systems
can be compared with one another. In this context, the mixer type, type of
heating/cooling and loading weight used are of decisive importance.
6.1.4 Liquid heated mixers shall be equipped with a circu-
lation pump that has a capacity of at least 24 L/min at a back
pressure of approximately 500 mbars. The heat transfer me-
diumshallbestabilizedsiliconeoil,withamaximumviscosity
of 20 mm /s at 25°C. The oil temperature shall be monitored
by a device which has a resolution of 0.2°C or better.
6.1.5 Electricallyheatedmixerbowlsshallhaveaminimum
of one independent electric controller and a maximum of two
independent electric controllers that utilize modern control
techniquesandalgorithms.Thesecontrollersshallprovideboth
heatingandcoolingcycles.Thetemperaturecontrolensembles
that include the sensor, controller and actuators shall be
accurate to within 2.0°C throughout their working range.
Reported values shall have a precision of 0.2°C or better.
6.1.6 The torque recording ensemble shall be accurate to
NOTE 1—Top curve associated with temperature axis; bottom curve
0.25% of the reading.
associated with torque axis.
FIG. 1 Torque Rheometer Curve 6.1.7 For feeding flowable or granular sample materials a
loading device shall be used. For feeding other coarse materi-
als,apressureramactuatedmanuallyorpneumaticallyshallbe
used.Theloadingchutehastobemountedontothemixer,with
material is compacted, melted, cross-linked, hardened, and
a ram and eithera5or2kg weight or with an adjustable
crushed under constant shear.
pneumatic cylinder (see Note 2).
6.1.8 For recording of the stock temperature during the
5. Significance and Use
measuring process, the temperature measuring device is
5.1 The continuous recording of torque and temperature
mountedfrombelowintothebottomofthemeasuringmixerin
whilegoingthroughthesevariousstagescanbeusedtopredict
such a way that it penetrates 1.5 mm into the mixer bowl. The
the behavior of the material during processing.
stock temperature versus time, is recorded simultaneously
5.2 The torque rheometer test has two important functions.
together with the torque curve.
First, it is a means to predict flow/viscosity and cure charac-
6.1.9 SoftBrassSpatulaorStiffBrassBristleCleaningTool.
teristics of pourable thermosetting compounds. For example,
7. Hazards
the test provides useful data to predict the processibility of a
material in a particular molding method. This information is 7.1 Do not exceed the rated power of the instrument as
damage to the mixer or to the torque rheometer may result.
also useful to optimize process conditions for a particular
material such as the minimum pressure to fill a mold and the
7.2 Do not attempt to clean or insert objects into the mixer
time to cure a part.Asecond capability of the test is to provide
while it is running.
a graphic record of the batch-to-batch uniformity of the
7.3 Use adequate exhausts and safety devices necessary to
molding compound.
meet applicable safety codes.
7.4 Use insulated gloves to protect operator from hot mixer
6. Apparatus
surface.
6.1 Torque Rheometer, with a mixing bowl.
7.5 Refer to manufacturers’ operating instructions.
6.1.1 The torque rheometer shall be equipped with a drive
motorwithaload-independentspeedstabilityof 60.5%ofthe
8. Sampling
top rotor speed.
8.1 A batch of compound shall be considered as a unit of
6.1.2 The recording device selected shall be capable of
manufacture as prepared for shipment and may consist of a
recording the measurable variables of torque, stock tempera-
manufacturer’s blend of one or more production runs of
ture, and rotation per minute (RPM) as a function of time.The
material.
rheometer should also be equipped with a real time RPM
8.2 Suitable methods of sampling shall follow Practice
indicator.
D1898. A 400-g sample will be sufficient for tests required.
6.1.3 For the measurement, a surface hardened laboratory
internal mixer is used, specified by a bowl volume of 25, 30 or
8.3 Crushanycompoundinapreformstatetoaparticlesize
60 cm , that can be attached to the above mentioned torque
that would pass through the loading chute.
rheometer. Either a set of triangular or roller blades shall be
9. Sample Selection, Handling and Use for Rheometer
used counter-rotating with a speed ratio of 3:2 (left to right).
Standardization
(The mixer bowl may be heated with a circulated liquid
temperature controlled by a thermostat or electrically with at 9.1 Selection—The selection of the sample should be deter-
least two heating zones (see Note 2). mined by the use for which it is intended. If it is to be an
D3795 − 00a (2006)
intralaboratory standardization sample, (for example in a tions shall be done when data from a reference material
material compounder’s laboratory), the sample should be calibration versus the control chart, causes the instrumentation
chosen to closely approximate the materials expected to be to be suspect.
tested. (For compounders having a wide range of product
9.2.1 EquipmentCalibration—Thetorque,temperaturecon-
plasticities it is recommended that one sample for each
trol, and RPM systems shall be calibrated using national or
maximum torque range be available.) For interlaboratory
international regulatory body traceable standards and proce-
standardization,thesampleshouldbeoftheproducttypebeing
dures.
molded.
9.2.2 Record all “as found” measured values versus ac-
9.1.1 Handling:
cepted values before making any attempts at corrective action.
9.1.1.1 Once the selection of the sample has been agreed
All“ as left” measured values should be recorded upon com-
upon among the interested parties it shall be gathered in
pleting any adjustments.
sufficientquantitythatthesupplyofsampleforeachlaboratory
9.2.3 Upon completion of the calibration, provide a Certifi-
can be expected to outlast the need to change the mixing head
cate of Calibration. This document shall include the data
or blades by about 50% of the life of the head or blades. This
values, traceability of each standard used, and a statistical
is to avoid running out of standardization standard at the same
estimation of the uncertainties associated with each procedure
timeasanequipmentchangetakesplaceontherheometer(see
and standard versus national or international regulatory body
Note 3).
standards.
NOTE3—Thedeterminationforwearofthemeasuringmixerandblades
shall be measured volumetrically. The equipment manufacturer shall
10. Procedure
provide the procedure and values for the individual measuring mixers.
10.1 Select a mixer temperature that corresponds to the
9.1.1.2 Itisrecommendedthatthesamplebebrokenupinto
mean processing temperature of the material to be tested:
preweighed charges, the charge weight being based on the
Material Type (granular) Suggested Temperature, °C
specific gravity of the sample and the size of the mixing head
in use on the respective rheometers. These should be heat-
Alkyd 150
Crosslineable polyethylene 145, 175
sealedinindividualpolyethylenepouches.Ifthesamplesareof
DAP 150
any compound which has a defined shelf-life, they should be
Epoxy 150, 175
stored at, or near freezing in order to protect their plasticity
Phenolic 125, 150
Polyester 150
properties from changing. If the samples have indefinite
Silicone 140
shelf-life, they should be stored below the temperature at
Silicone-epoxy 140
which volatile material could be driven off due to excessive
10.2 Adjust the required mixer temperature at the bath and
vapor pressure.
the circulation thermostat or at the temperature controller for
9.1.1.3 Samples stored in this manner should be allowed a
theelectricallyheatedmixer.Conditionthemeasuringmixerat
full 24-h to reach equilibrium temperature with standard
this temperature until the mixer has reached equilibrium.
laboratory conditions of 23 6 2°C before removing from
storage pouches for standardization testing.
10.3 Start the torque rheometer before starting the first test
9.1.2 Samples should be used to test the standardization of
andobtainauniformtemperatureinthesystem.Makesurethat
therespectiverheometersatagreeduponintervalsofoperation.
the mixing blades are rotating during this time.
It is recommended that the standardization be tested at least
10.4 Weighthetestchargewithaprecisionof 60.1gandto
every 120 h of operation. Operating time is defined not as the
an accuracy of 0.5% of the total sample mass for each
total testing time; but rather as the total elapsed time that the
measurement. Depending on the density of the material, the
rheometer is powered up. This would be once per week for a
optimum charge for the measuring mixer may vary. Eq 2 is a
full time, five day per week laboratory operation. The samples
reference for determining a good load charge:
shouldbeusedtwoatatime,wherethefirstsampletestedwill
G 50.7 3V 3p (2)
be used to condition the instrument mixing head and blades,
and the second sample will be used as actual standardization
where:
data.
G = the sample mass, in kilograms,
9.1.2.1 It is recommended that sample pouches be drawn
V = the free mixer volume, in liters,
from storage five at a time for conditioning to ambient
P = the density of sample material, in kilograms per liter,
conditions. The first will be used for rheometer conditioning,
and (density in accordance with Test Method D792).
the second for standardization testing, and the remaining be
The density of the sample material shall be given with an
used for additional standardization testing in the event that the
accuracy of6 0.03 kg/L.
instrument needs to be adjusted, or restandardized. If the extra
three samples are not needed they may be safely returned to
10.5 Start the drive of the torque rheometer and adjust the
storage if they have not been opened.
rotor speed to 40 RPM. Charge the running mixer with the
9.2 Calibration—To ensure reliability of this test method, it sample quickly and as uniformly as possible using the loading
is essential t
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