1、Designation: D6204 15Standard Test Method forRubberMeasurement of Unvulcanized RheologicalProperties Using Rotorless Shear Rheometers1This standard is issued under the fixed designation D6204; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the use of a rotorless oscillatingshear rheometer for the measurement of
3、 the flow properties ofraw rubber and unvulcanized rubber compounds. These flowproperties are related to factory processing.1.2 The values stated in SI units are to be regarded asstandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of th
4、esafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1485 Practice for Rubber f
5、rom Natural SourcesSampling and Sample PreparationD1646 Test Methods for RubberViscosity, StressRelaxation, and Pre-Vulcanization Characteristics(Mooney Viscometer)D3896 Practice for Rubber From Synthetic SourcesSamplingD4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber a
6、nd Carbon Black ManufacturingIndustriesD5289 Test Method for Rubber PropertyVulcanizationUsing Rotorless Cure MetersD6601 Test Method for Rubber PropertiesMeasurementof Cure and After-Cure Dynamic Properties Using aRotorless Shear Rheometer3. Terminology3.1 Definitions of Terms Specific to This Stan
7、dard:3.1.1 complex shear modulus, G*, nthe ratio of peakamplitude shear stress to peak amplitude shear strain;mathematically, G*=(S*/Area )/Strain=(G2+ G”2)1/2.3.1.2 complex torque, S*, nthe peak amplitude torqueresponse measured by a reaction torque transducer for asinusoidally applied strain; math
8、ematically, S* is computed byS*=(S2+ S”2)1/2.3.1.3 dynamic complex viscosity *, nthe ratio of thecomplex shear modulus, G* to the oscillation frequency, ,inradians per second.3.1.4 elastic torque, S, nthe peak amplitude torque com-ponent that is in phase with a sinusoidally applied strain.3.1.5 loss
9、 angle, ,nthe phase angle by which thecomplex torque (S*) leads a sinusoidally applied strain.3.1.6 loss factor, tan ,nthe ratio of loss modulus tostorage modulus, or the ratio of viscous torque to elastictorque; mathematically, tan = G”/G = S”/S.3.1.7 loss shear modulus G”, nthe ratio of (viscous)
10、peakamplitude shear stress to peak amplitude shear strain for thetorque component 90 out of phase with a sinusoidally appliedstrain; mathematically, G” =(S”/Area)/Peak Strain.3.1.8 real dynamic viscosity, ,nthe ratio of the loss shearmodulus, G” to the oscillation frequency, , in radians persecond.3
11、.1.9 storage shear modulus, G, nthe ratio of (elastic)peak amplitude shear stress to peak amplitude shear strain forthe torque component in phase with a sinusoidally appliedstrain; mathematically, G=(S/Area)/Peak Strain.3.1.10 viscous torque, S”, nthe peak amplitude torquecomponent, which is 90 out
12、of phase with a sinusoidallyapplied strain.4. Summary of Test Method4.1 A rubber test specimen is contained in a die cavity thatis closed and maintained at an elevated temperature. The cavityis formed by two dies, one of which is oscillated through arotary amplitude. This action produces a sinusoida
13、l torsionalstrain in the test specimen, resulting in a sinusoidal torque,which measures a viscoelastic quality of the test specimen. The1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand is the direct responsibility of Subcommittee D11.12 on Processability Tests.Current e
14、dition approved Nov. 1, 2015. Published December 2015. Originallyapproved in 1997. Last previous edition approved in 2012 as D6204 12. DOI:10.1520/D6204-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of AST
15、MStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1test specimen can be either a raw natural or synthetic rubber oran uncured rubber compound.
16、4.2 These viscoelastic measurements can be made based on(1) a frequency sweep, in which the frequency is programmedto change in steps under constant strain amplitude and tem-perature conditions, (2) a strain sweep, in which the strainamplitude is programmed to change in steps under constantfrequency
17、 and temperature conditions, or (3) a temperaturesweep, in which the temperature is programmed to eitherincrease or decrease under constant strain amplitude andfrequency conditions. A timed test may also be performed inwhich a sinusoidal strain is applied for a given time periodunder constant strain
18、 amplitude, frequency, and temperatureconditions.4.2.1 For a frequency sweep test, the instrument is typicallyprogrammed to increase the frequency with each subsequentstep change. For a strain sweep test, the instrument is usuallyprogrammed to increase the strain amplitude with each subse-quent step
19、 change. This is done to minimize the influence ofprior test conditions on subsequent test steps. For temperaturesweeps, the temperature may be programmed either to increaseor decrease with each subsequent step change, depending onthe effects to be studied. The results from increasing frequency,stra
20、in amplitude, or temperature may not be the same as resultsfrom decreasing these test parameters.4.3 Rheological properties are measured for each set offrequency, strain, and temperature conditions. These propertiescan be measured as combinations of elastic torque S, viscoustorque S”, storage shear
21、modulus G, loss shear modulus G”,tan , complex dynamic viscosity *, and real dynamicviscosity .4.4 This standard is organized in three different parts (A, B,and C), which can be run in the following combinations:ABA, BA, B, CA, CB, CC4.5 These three parts are described below:4.5.1 Part A is a rapid
22、three-point frequency sweep per-formed at a low strain of 7 % to relate to differences in averagemolecular weight, molecular weight distribution, and longchain branching for raw elastomers and to relate to differencesin flowability, shear thinning, and die swell for mixed batches.4.5.2 Part B is a r
23、apid two-point frequency sweep performedat a moderate strain of 100 % (or higher) to relate to geldifferences with raw elastomers and to relate to differences inhigher shear rate viscosity and die swell for mixed batches. Thehigher applied strain is commonly needed to help break up gelstructure in s
24、ome raw elastomers and break up filler aggregatenetworks for mixed batches.Although 100 % strain is the morecommon test condition, significantly higher test sensitivity ispossible by performing this frequency sweep at 200 % strain orhigher.4.5.3 Part C is a linear ramped temperature rise fromprocess
25、ing temperature (typically 100C) to cure temperature(usually 140, 160, or 180C) in a predetermined time period.This ramped temperature cure is performed to enhance statis-tical test sensitivity to real differences in scorch times provid-ing better scorch control than traditional isothermal cure test
26、s(Test Method D5289), and to provide a controlled transitionfrom Part A or Part B tests, or both, in this method to a curetest.5. Significance and Use5.1 This test method is used to measure viscoelastic prop-erties of raw rubber as well as unvulcanized rubber com-pounds. These viscoelastic propertie
27、s may relate to factoryprocessing behavior.5.2 This test method may be used for quality control inrubber manufacturing processes and for research and develop-ment testing of raw rubber and rubber compounds. This testmethod may also be used for evaluating compound differencesresulting from the use of
28、 different compounding materials.6. Apparatus6.1 Torsion Strain Rotorless Oscillating Rheometer With aSealed CavityThis type of rheometer measures the elastictorque S and viscous torque S” produced by oscillatingangular strain of set amplitude and frequency in a completelyclosed and sealed test cavi
29、ty.6.2 Sealed Die CavityThe sealed die cavity is formed bytwo conical surface dies. In the measuring position, the twodies are fixed a specified distance apart so that the cavity isclosed and sealed (see Fig. 1).6.3 Die GapFor the sealed cavity, no gap shall exist at theedges of the dies. At the cen
30、ter of the dies, the die gap shall beset at 0.45 6 0.05 mm.6.4 Die Closing MechanismFor the sealed cavity, a pneu-matic cylinder or other device shall close the dies and holdthem closed during the test with a force not less than 11 kN(2500 lbf).6.5 Die Oscillating SystemThe die oscillating systemcon
31、sists of a direct drive motor that imparts a torsionaloscillating movement to the lower die in the cavity plane.6.5.1 The oscillation amplitude can be varied, but a selec-tion of 60.5 arc (7.0 % shear strain) is preferred for frequencysweep tests. The oscillation frequency can be varied between0.03
32、and 30 Hz.6.6 Torque Measuring SystemThe torque measuring sys-tem shall measure the resultant shear torque.6.6.1 The torque measuring device shall be rigidly coupledto one of the dies, any deformation between the die and deviceshall be negligibly small, and the device shall generate a signalthat is
33、proportional to the torque. The total error resulting fromzero point error, sensitivity error, linearity, and repeatabilityerrors shall not exceed 1 % of the selected measuring range.6.6.2 The torque recording device shall be used to record thesignal from the torque measuring device and shall have a
34、response time for full scale deflection of the torque scale of 1s or less. The torque shall be recorded with an accuracy of60.5 % of the range. Torque recording devices may includeanalog chart recorders, printers, plotters, or computers.D6204 1526.6.3 A reference torque device is required to calibra
35、te thetorque measurement system. A torque standard shall be used tocalibrate the torque measuring system at the selected angulardisplacement by clamping a steel torsion rod to the oscillatingand the torque measuring dies of the torsion shear rheometer(see Fig. 2). The reference values for angular di
36、splacement andcorresponding torque shall be established by the manufacturerfor each torque standard.6.7 Reference Test TemperatureThe standard referencetest temperature shall be 100C (212F) or 125C (257F) forprocessability measurements. Tests may be carried out at othertemperatures when appropriate.
37、6.8 Temperature Control SystemThis system shall permitthe set point temperature to be varied between 40C and 220Cwith an accuracy of 60.3C or better.6.8.1 The dies shall heat to the set point temperature in 1.0min or less from closure of the test cavity. Once the initialheating-up time has been comp
38、leted, die temperature shall notvary by more than 60.3C for the remainder of a test at a settemperature. When the set temperature is changed in a pro-grammed temperature sweep (step changes in temperature),rheological measurements shall not be recorded until the dietemperatures are within 60.3C of t
39、he new set temperature forat least 30 s. When the set temperature is set for a rampedFIG. 1 Typical Sealed Torsion Shear Rotorless CuremeterD6204 153increase as described in Part C of this test method, thetemperature shall not overshoot by more than 3C withrecovery to within 60.3C within 1 min of co
40、ntrol at theplateau temperature at the end of the temperature ramp.6.8.2 Temperature distribution within the test piece shall beas uniform as possible. Within the deformation zone, a toler-ance of 61C of the average test piece temperature shall not beexceeded.6.8.3 Die temperature is determined by a
41、 temperature sensorused for control. The difference between the die temperatureand the average test piece temperature shall not be more than2C. Temperature measurement accuracy shall be 60.3C forthe die temperature sensor.7. Sampling7.1 The sample shall be taken from a raw rubber or rubbercompound a
42、s required by the mixing method or other samplinginstructions. Condition a raw rubber sample in accordance withPractice D1485 or Practice D3896 until it has reached roomtemperature (23 6 3C (73 6 5F) throughout.7.2 The sample shall be homogeneous, at room temperature,and as free of air as possible.
43、Raw rubber samples should betested as received, that is unmassed (not milled). If the materialcannot be tested unmassed, then follow the sample preparationsection of Test Methods D1646. Rubber compound samplesshall be in the form of a sheet. Rubber compounds with orwithout curatives may be tested us
44、ing Parts A or B of thismethod.Avulcanizable rubber compound is required for Part Ctesting.7.3 The temperature of the sample and its heat history cansignificantly affect test results. For part C testing, the sampleshall be conditioned at 23 6 1C (73 6 2F) for at least 1 hbefore testing.7.4 In produc
45、tion control testing, samples may be testedwithout the conditioning period, but care should be taken tominimize temperature and heat history variations prior totesting.8. Test Specimen8.1 The test specimen should be circular, with a diametersmaller than the test chamber of the instrument to be used.
46、8.2 The test specimen is considered to be of proper size (116to 160 % of the test cavity volume) when a small bead ofrubber compound is extruded uniformly around the peripheryof the dies as they are closed. For example, an instrument witha test cavity volume of 3.44 cm3requires a test specimenvolume
47、 between 4.0 and 5.5 cm3(4.6 to 6.3 g of rubbercompound with a specific gravity of 1.15). Materials of eitherlow or high viscosity may require a narrower range of sampleFIG. 2 Typical Torque Standard Calibration Devices for Torsion Shear CuremetersD6204 154volume for repeatable results. Undersized t
48、est specimens cancause low cavity pressure and low torque readings. Oversizedtest specimens cool the dies excessively during the early part ofthe test period, affecting the vulcanization characteristicsmeasured in Part C.8.3 Raw rubber test specimens in a sealed cavity oscillatingrheometer must be p
49、re-conditioned in the instrument beforerheological measurements are made to improve test precision.A programmed preconditioning step shall consist of oscillatingthe specimen at 0.5 Hz, 6 2.8 % strain, 100C (or 125C) forthe time interval specified in Table 1.8.4 Compounded rubber test specimens must also be pre-conditioned in a sealed cavity oscillating rheometer beforerheological measurements are made to improve test precision.A programmed pre-conditioned step shall consist of oscillatingthe specimen
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