1、Designation: D 2538 02Standard Practice forFusion of Poly(Vinyl Chloride) (PVC) Compounds Using aTorque Rheometer1This standard is issued under the fixed designation D 2538; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the relative fusion characteristics ofpoly(vinyl chloride) compounds.1.2 The test procedures
3、appear in the following order:SectionFusion Test 9Thermal Stability Test 10Color-Hold Stability Test 11Shear Stability Test 121.3 The values stated in SI units are to be regarded as thestandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use.
4、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. Specific hazardsstatements are given in Section 8.NOTE 1There are no ISO standards covering the primary subjectmatter of
5、 this ASTM standard.2. Referenced Documents2.1 ASTM Standards:2D 883 Terminology Relating to PlasticsD 1600 Terminology for Abbreviated Terms Relating toPlasticsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 DefinitionsDefinitions a
6、re in accordance with Termi-nologies D 883 and D 1600 unless otherwise indicated.4. Summary of Practice4.1 A sample of powder-mix compound is added to theheated roller mixer chamber and is transformed into a fusedmass.4.2 The resulting torque curve can be used to determine therelative fusion time an
7、d fusion characteristics.5. Significance and Use5.1 When PVC compounds are mixed under appropriateconditions of heat and shear, a fused mass is produced. Thismass has certain melt characteristics which can be defined witha torque rheometer operated under fixed conditions of shearand temperature. The
8、 fusion characteristics of a PVC com-pound are manifest as fusion time, fusion torque, melt torque,melt viscosity, and heat and color stability.5.2 A control lot is to be used as a standard against whichother test results are to be compared. Test data are to beevaluated relative to the control lot.6
9、. Apparatus6.1 Microprocessor Torque Rheometer,3equipped with ahigh-shear mixer with roller-style blades, bowl-jacket thermo-couple, stock thermocouple, and temperature recorder.NOTE 2A torque rheometer without microprocessor capability can beused to perform the fusion, thermal stability, and color
10、hold tests.6.1.1 For flexible and rigid compounds, use a Type 6 rollerhead with a rotor ratio of 3 Drive: 2 Driven.NOTE 3A Type 5 roller head can also be used, but the data generatedcannot be compared with the Type 6 data.6.2 Quick-Loading Powder Chute or equivalent.6.3 Brass Knife.6.4 Brass Wool or
11、 Brush.6.5 Insulated Gloves.6.6 Balance, 500-g minimum capacity, with a 0.1-g sensi-tivity.1This practice is under the jurisdiction ofASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.15 on Thermoplastic Materials.Current edition approved August 10, 2002. Published O
12、ctober 2002. Originallypublished as D 2538 69. Last previous edition D 2538 95(01).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary pa
13、ge onthe ASTM website.3Suitable equipment may be obtained from C. W. Brabender, 50 E. Wesley St.,South Hackensack, NJ 07606, and Haake Buchler Instruments, 244 Saddle RiverRd., Saddle Brook, NJ 07662.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,
14、 United States.6.7 Beaker, stainless steel, 400 mL.6.8 Oven.6.9 Aluminum Foil.6.10 Timer.6.11 Long-Nose Pliers.6.12 Hand-Press Mold.7. Materials7.1 Poly(Vinyl Chloride) Resin.7.2 Filter.7.3 Lubricants.7.4 Plasticizer.7.5 Process-Aid.7.6 Impact Modifier.7.7 Stabilizer.7.8 Pigments.8. Hazards8.1 Do no
15、t exceed the power capacity of the instrument, asdamage to the mixer or to the torque rheometer may result.8.2 Do not attempt to clean or poke objects into the mixerwhile it is running.8.3 Gloves with sufficient insulation to enable the operatorto handle the hot equipment should be worn when conduct
16、ingthese tests.9. Fusion Test Method9.1 Compound Preparation:9.1.1 The compound may be beaker-mixed, blended in anintensive mixer or a ribbon blender, or blended and pelletized.If the compound is beaker-mixed, the total weight of thecompound should equal the amount charged to the roller-headbowl.9.2
17、 Equipment Preparation:9.2.1 Mount the roller head on the torque rheometer.9.2.2 Select a temperature/rotor speed combination that willpermit the test to be completed within a reasonable timeconstraint. Suggested combinations for several types of PVCcompound are found in Appendix X2.9.2.3 With the m
18、ixer empty and running, zero the recordingpen on the chart.9.3 Procedure:9.3.1 Determine the sample size to be added to the mixer,using the following formula:sample size 5 V 2 D! 3 65 %# 3 specific gravity (1)where:V = volume of mixer bowl without rotors, andD = volume displacement or rotors.NOTE 4T
19、he correct sample size for the mixer is when the fusion curvewill duplicate itself. As the mixer wears, it will be necessary to increasethe sample size to reproduce a fusion curve equivalent to previous curves.9.3.2 Weigh a sample of the test compound in accordancewith 9.3.1. With the mixer running,
20、 position the quick-loadingchute on the roller-head mixer and pour in the sample com-pound. Place the ram into the chute and add the weight. Whenthe torque curve indicates maximum torque has been reached,remove the loading chute and weight.9.3.3 Continue mixing until the melt torque achieves asteady
21、 state.9.3.4 Stop the mixer and open the bowl. Clean the com-pound from the bowl and blades using the brass knife or wool,or both.9.3.5 Reassemble the mixing bowl and repeat 9.3.2-9.3.4for additional tests. Since some cooling takes place whencleaning the bowl, allow sufficient time to confirm that t
22、hemixing bowl has reached equilibrium at the test temperaturebefore using again.NOTE 5The quick-loading chute should be at the same temperature atthe start of each test. Heat or cool as required.9.4 Interpretation of Torque Rheometer Curve (Fig. 1):9.4.1 Fusion TorqueThe point of maximum torque.9.4.
23、2 Fusion TimeThe time from the point of loading tothe point of maximum torque.9.4.3 Melt TorqueThe fusion where the torque curve isrelatively flat.9.5 ReportReport the following information:9.5.1 The fusion torque to the nearest 100 mg.9.5.1.1 Report to the nearest 25 mg when usinga0to1000scale.9.5.
24、2 The fusion time to the nearest12 min.9.5.3 The melt torque to the nearest 100 mg.9.5.3.1 Report to the nearest 25 mg when usinga0to1000scale.NOTE 6If the melt torque is not steady, approximate the value andFIG. 1 Torque Rheometer CurveD2538022note whether the torque is increasing or decreasing.9.5
25、.4 Temperature of test, rotor revolutions per minute, andsample size used.10. Thermal Stability Test Method10.1 Prepare the test compound in accordance with 9.1.10.2 Prepare the test equipment in accordance with 9.2.10.3 Procedure:10.3.1 Weigh a sample of the test compound in accordancewith 9.3.1. W
26、ith the mixer running, position the quick-loadingchute on the roller-head mixer and pour in the sample com-pound. Place the ram into the chute and add the weight. Whenthe torque curve indicates fusion, remove the loading chute andweight.10.3.2 Continue running until there is a sudden rise in thetorq
27、ue curve, indicating decomposition of the PVC compound.10.3.3 Stop the mixer and open the bowl. Clean the com-pound from the bowl and blades using the brass knife or wool,or both.10.3.4 Reassemble the mixing bowl and repeat 10.3.1-10.3.3 for additional tests. Confirm that the bowl has reachedthe tes
28、t temperature before starting.10.4 Interpretation of Torque Rheometer Curve (Fig. 1):10.4.1 Compound Heat StabilityThe time from the pointof maximum torque (fusion torque) to the point of suddentorque increase.10.5 ReportReport the following information:10.5.1 The compound heat stability to the near
29、est12 min,and10.5.2 The temperature of test, rotor revolutions per minute,and the sample size used.11. Color-Hold Stability Test Method11.1 Prepare the test compound in accordance with 9.1.11.2 Prepare the test equipment in accordance with 9.2.11.3 Procedure:11.3.1 Weigh a sample of the test compoun
30、d in accordancewith 9.3.1. With the mixer running, position the quick-loadingchute on the roller-head mixer and pour in the sample com-pound. Place the ram into the chute and add the weight. Whenthe torque curve indicates fusion, remove the loading chute andthe weight.11.3.2 Using the point of maxim
31、um torque (fusion torque)as zero time, remove a sample of the compound at regular timeintervals of 2, 3, or 5 min. Stop the rotors and use a pair oflong-nose pliers to remove a sample from the bowl. Restart therotors. Place the compound into a hand press to shape thesample. Trim the sample and retur
32、n the excess to the mixingbowl.11.3.3 Mount the samples in a sequential time order.11.3.4 Continue sampling until the desired color change hasbeen observed.NOTE 7Depleting the sample from the bowl can affect the amount ofworking the compound receives. Select a time sequence that does notremove more
33、than half the sample.11.3.5 Stop the mixer and open the bowl. Clean the com-pound from the bowl and blades, using the brass knife or wool,or both.11.3.6 Reassemble the mixing bowl and repeat 11.3.1-11.3.5 for additional tests. Confirm that the bowl has reachedthe test temperature before starting.11.
34、4 ReportReport the following information:11.4.1 The time to equivalent color change and11.4.2 The temperature of test, rotor revolutions per minute,and the sample size used.11.5 Alternative Procedure:11.5.1 Weigh a sample of the test compound in accordancewith 9.3.1. With the mixer running, position
35、 the quick-loadingchute on the roller-head mixer and pour in the sample com-pound. Place the ram into the chute and add the weight. Whenthe torque curve indicates fusion, remove the loading chute andthe weight.11.5.2 Using the point of maximum torque (fusion torque)as zero time, run the mixer until
36、the compound starts todiscolor. Stop the mixer, remove the contents, and press into aplaque.11.5.3 Clean the bowl and blades and reassemble the mixer.11.5.4 Run additional tests, stopping at the same point intime as 11.5.2.11.5.5 Measure the color of the plaque in a Hunter Colo-rimeter (or equivalen
37、t).11.6 ReportReport the following information:11.6.1 The color number measured on the pressed plaqueand11.6.2 The temperature of the test, rotor revolutions perminute, the sample size, and the time as determined in 11.5.2.12. Shear Stability Test Method12.1 Prepare the test compound in accordance w
38、ith 9.1.12.2 Prepare the test equipment in accordance with 9.2.NOTE 8Use the microprocessor torque rheometer for this test.12.3 Procedure:12.3.1 Set the microprocessor for the desired temperatureand program the revolutions per minute as follows:12.3.1.1 Run at preselected revolutions per minute for
39、tenmin.12.3.1.2 Return to 0 r/min.12.3.1.3 Program the speed control to run from 0 to 100r/min in 1 min and stop.12.3.2 When the bowl temperature has stabilized, weigh outa sample of the test compound. Position the quick-loadingchute on the roller-head mixer, turn on the torque rheometer,and pour in
40、 the sample compound. Place the ram into the chuteand add the weight. When the ram bottoms, remove the loadingchute.12.3.3 When the sample run is finished, use the micropro-cessor to plot the torque versus revolutions per minute. Use theplotted curve for analysis.12.3.4 When the mixer has stopped, o
41、pen the bowl. Cleanthe compound from the bowl and blades, using the brass knifeor wool, or both.12.3.5 Reassemble the mixing bowl and repeat 12.3.1-12.3.5 for additional tests.13. Interpretation of Torque Rheometer Results13.1 Visual Analysis:D253802313.1.1 The first 10 min of the graph represents a
42、 standardfusion curve which can be used to determine the fusion time,fusion torque and melt, or stabilized torque.13.1.2 The torque versus revolutions per minute plot can beused as a relative comparison of shear sensitivity.13.1.3 Bearing in mind that a straight inclined line woulddenote a Newtonian
43、 material, the shear sensitivity can beestimated by the degree of arc.Alarge arc or loop denotes moreshear-sensitive material than does a smaller arc or loop. Avisual observation can be made to determine the relative shearsensitivity between sample materials.13.2 Technical Analysis:13.2.1 The torque
44、 versus revolutions per minute plottedgraph can be used in conjunction with the microprocessorsoftware to provide a shear-sensitivity index number. Thesoftware is programmed to give such a number. A higher indexnumber denotes a more shear-sensitive material.13.2.2 The calculation programmed into the
45、 software isshown in the Appendix X1.14. Precision and Bias14.1 Table 1 is based on a round robin4conducted in 2001in accordance with Practice E 691, involving five rigid PVCdry blend compounds tested by ten laboratories. All laborato-ries used a computerized torque rheometer and a single zoneelectr
46、ically heated mixer/measuring head (3:2 gear ratio) toprocess the samples. For each material, all the samples wereprepared at one source, but the individual specimens wereprepared at the laboratories that tested them. Each sample wastested three times on two separate days yielding six points perdata
47、 value.NOTE 9Caution: The explanation of r and R (14.2-14.2.3) is onlyintended to present a meaningful way of considering the approximateprecision of this test method. The data in Table 1 should not be applied toacceptance or rejection of materials, as these data apply only to the4Supporting data gi
48、ving results of the round robin have been filed at ASTMInternational Headquarters. Request RR: D20-1237.TABLE 1 Round Robin Test ResultsParameter 1 Fusion Torque, Point X (Newton-meters), Mean Level in Ascending OrderWithin Laboratories Between LaboratoriesMaterial Mean Level Srr (r) SRR(R)Material
49、C 29.5 0.58 1.62 5.5 % 2.40 6.72 22.8 %Material B 30.3 0.78 2.18 7.2 % 2.47 6.92 22.8 %Material E 31.4 0.39 1.08 3.4 % 2.00 5.59 17.8 %Material A 35.2 1.15 3.21 9.1 % 2.57 7.19 20.4 %Material D 39.1 1.05 2.94 7.5 % 3.20 8.97 23.0 %Pooled Values 33.1 0.79 2.21 6.6 % 2.53 7.08 21.4 %Parameter 2 Fusion Torque Temperature, (degrees Celsius), Mean Level in Ascending OrderWithin Laboratories Between LaboratoriesMaterial Mean Level Srr (r) SRR(R)Material B 171.0 0.97 2.71 1.6 % 1.52 4.25 2.5 %Material D 174.0 1.62 4.53 2.6 % 3.72 10.41 6.0 %Material E 181.6 1.3
