Designation: D2538 − 02 (Reapproved 2010) Standard Practice for Fusion of Poly(Vinyl Chloride) (PVC) Compounds Using a Torque Rheometer1 This standard is issued under the fixed designation D2538; 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 4. Summary of Practice 1.1 This practice covers the relative fusion characteristics of 4.1 A sample of powder-mix compound is added to the poly(vinyl chloride) compounds. heated roller mixer chamber and is transformed into a fused 1.2 The test procedures appear in the following order: mass. Section 4.2 The resulting torque curve can be used to determine the relative fusion time and fusion characteristics. Fusion Test 9 Thermal Stability Test 10 5. Significance and Use Color-Hold Stability Test 11 Shear Stability Test 12 5.1 When PVC compounds are mixed under appropriate 1.3 The values stated in SI units are to be regarded as the conditions of heat and shear, a fused mass is produced. This standard. mass has certain melt characteristics which can be defined with 1.4 This standard does not purport to address all of the a torque rheometer operated under fixed conditions of shear safety concerns, if any, associated with its use. It is the and temperature. The fusion characteristics of a PVC com- responsibility of the user of this standard to establish appro- pound are manifest as fusion time, fusion torque, melt torque, priate safety and health practices and determine the applica- melt viscosity, and heat and color stability. bility of regulatory limitations prior to use. Specific hazards 5.2 A control lot is to be used as a standard against which statements are given in Section 8. other test results are to be compared. Test data are to be evaluated relative to the control lot. NOTE 1—There are no ISO standards covering the primary subject matter of this ASTM standard. 6. Apparatus 2. Referenced Documents 6.1 Microprocessor Torque Rheometer,3equipped with a high-shear mixer with roller-style blades, bowl-jacket 2.1 ASTM Standards:2 thermocouple, stock thermocouple, and temperature recorder. D883 Terminology Relating to Plastics D1600 Terminology for Abbreviated Terms Relating to Plas- NOTE 2—A torque rheometer without microprocessor capability can be tics used to perform the fusion, thermal stability, and color hold tests. E691 Practice for Conducting an Interlaboratory Study to 6.1.1 For flexible and rigid compounds, use a Type 6 roller Determine the Precision of a Test Method head with a rotor ratio of 3 Drive: 2 Driven. NOTE 3—A Type 5 roller head can also be used, but the data generated 3. Terminology cannot be compared with the Type 6 data. 3.1 Definitions—Definitions are in accordance with Termi- 6.2 Quick-Loading Powder Chute or equivalent. nologies D883 and D1600 unless otherwise indicated. 6.3 Brass Knife. 6.4 Brass Wool or Brush. 1 This practice is under the jurisdiction of ASTM Committee D20 on Plastics and 6.5 Insulated Gloves. is the direct responsibility of Subcommittee D20.15 on Thermoplastic Materials. 6.6 Balance, 500-g minimum capacity, with a 0.1-g sensi- Current edition approved Nov. 1, 2010. Published March 2011. Originally approved in 1969. Last previous edition approved in 2002 as D2538 – 02. tivity. DOI:10.1520/D2538-02R10. 2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or 3 contact ASTM Customer Service at
[email protected]. For Annual Book of ASTM Suitable equipment may be obtained from C. W. Brabender, 50 E. Wesley St., Standards volume information, refer to the standard’s Document Summary page on South Hackensack, NJ 07606, and Haake Buchler Instruments, 244 Saddle River the ASTM website. Rd., Saddle Brook, NJ 07662. Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States Copyright by ASTM Int'l (all rights reserved); 1 2 Weigh a sample of the test compound in accordance with 9. 2 .3 Continue mixing until the melt torque achieves a bowl. allow sufficient time to confirm that the 9. 6. or blended and pelletized.2 Select a temperature/rotor speed combination that will or both. If the compound is beaker-mixed. 8. using the following formula: 9.2.2 Do not attempt to clean or poke objects into the mixer while it is running. 6.3. 1 Torque Rheometer Curve to handle the hot equipment should be worn when conducting these tests. compound should equal the amount charged to the roller-head 9.2-9. 8. When intensive mixer or a ribbon blender. 9. 7. position the quick-loading 9.4. zero the recording mixing bowl has reached equilibrium at the test temperature pen on the chart.4. it will be necessary to increase 9. 1): sample size 5 @ ~ V 2 D ! 3 65 % # 3 specific gravity (1) 9. the start of each test.3 Procedure: NOTE 5—The quick-loading chute should be at the same temperature at 9.4 Stop the mixer and open the bowl. 7. Copyright by ASTM Int'l (all rights reserved).5 Reassemble the mixing bowl and repeat 9. stainless steel.5 Process-Aid.8 Pigments. D2538 − 02 (2010) 6. relatively flat.3 Gloves with sufficient insulation to enable the operator FIG. 7. Clean the com- 9. and 9. Place the ram into the chute and add the weight. 9.6 Impact Modifier. 9.3. cleaning the bowl. as damage to the mixer or to the torque rheometer may result.11 Long-Nose Pliers.5.3.8 Oven. 9. 7.3.4 Interpretation of Torque Rheometer Curve (Fig. As the mixer wears. the total weight of the remove the loading chute and weight. With the mixer running.3 With the mixer empty and running. blended in an pound. Materials 7.1 The fusion torque to the nearest 100 m·g.1. 6. 8. the torque curve indicates maximum torque has been reached. Hazards 8.2 Equipment Preparation: 9.3.2. 7.10 Timer. 6. 7. steady state. NOTE 4—The correct sample size for the mixer is when the fusion curve will duplicate itself. 9.1.2 Filter.1 Determine the sample size to be added to the mixer.2.3.2 Fusion Time—The time from the point of loading to where: the point of maximum torque. V = volume of mixer bowl without rotors.12 Hand-Press Mold. 7. Heat or cool as required.4.3 Melt Torque—The fusion where the torque curve is D = volume displacement or rotors. 400 mL. Suggested combinations for several types of PVC for additional tests.4 constraint.9 Aluminum Foil.1 Compound Preparation: chute on the roller-head mixer and pour in the sample com- 9. Fusion Test Method 9. permit the test to be completed within a reasonable time 9.1 Do not exceed the power capacity of the instrument. 6.1 Fusion Torque—The point of maximum torque.5 Report—Report the following information: the sample size to reproduce a fusion curve equivalent to previous curves. before using again. 7.3. 9.7 Beaker.4 Plasticizer.1 Poly(Vinyl Chloride) Resin.7 Stabilizer.1 The compound may be beaker-mixed.3.3 Lubricants. pound from the bowl and blades using the brass knife or wool.1 Mount the roller head on the torque rheometer. Since some cooling takes place when compound are found in Appendix X2. When the ram bottoms. 9. position the quick-loading the torque curve indicates fusion. With the mixer running. NOTE 6—If the melt torque is not steady.3.1 The color number measured on the pressed plaque 10. Confirm that the bowl has 11.3.3.3.4. and or both.1 Prepare the test compound in accordance with 9. Place the compound into a hand press to shape the and pour in the sample compound.4 Reassemble the mixing bowl and repeat plaque.3.1.2 Return to 0 r/min.1 Prepare the test compound in accordance with 9.5.6. 10. 11. pound. With the mixer running.5.5 Report—Report the following information: and 10.1 The time to equivalent color change and 11.5. NOTE 8—Use the microprocessor torque rheometer for this test. and press into a 10.1 Report to the nearest 25 m·g when using a 0 to 1000 working the compound receives. 11. rotor revolutions per minute. 3.5. remove a sample of the compound at regular time 12.2 Using the point of maximum torque (fusion torque) r/min in 1 min and stop.3.3.3. reached the test temperature before starting. 11. remove more than half the sample.1. pound from the bowl and blades.4. remove the loading chute and chute on the roller-head mixer and pour in the sample com- weight.3.1. Position the quick-loading long-nose pliers to remove a sample from the bowl.3 The melt torque to the nearest 100 m·g. position the quick-loading and program the revolutions per minute as follows: chute on the roller-head mixer and pour in the sample com. 1): 11.3.1 Run at preselected revolutions per minute for ten pound.2.1.3 Procedure: and the sample size used. approximate the value and 11. chute.2 Prepare the test equipment in accordance with 9. rotor revolutions per and minute.3. 3 . 11.1 The compound heat stability to the nearest 1⁄2 min. run the mixer until the compound starts to or both.3 Program the speed control to run from 0 to 100 11.1 Weigh a sample of the test compound in accordance 12.4 Report—Report the following information: 10. remove the loading chute and torque curve.4.2 Prepare the test equipment in accordance with 9.2 The fusion time to the nearest 1⁄2 min. 12. Place the ram into the chute and add the weight. 10.3. or 5 min. 10. 11.4 Temperature of test. Select a time sequence that does not scale.1. been observed. turn on the torque rheometer. 10. rotor revolutions per minute.5 Measure the color of the plaque in a Hunter Colo- 10.6.5. the torque curve indicates fusion.3 Procedure: 12.3. sample size used.1.5. indicating decomposition of the PVC compound.3. 12. D2538 − 02 (2010) 9.3 for additional tests.2 The temperature of the test.5 Stop the mixer and open the bowl. 9.2. 10.1 Compound Heat Stability—The time from the point rimeter (or equivalent).1 Weigh a sample of the test compound in accordance pound. weigh out intervals of 2. NOTE 7—Depleting the sample from the bowl can affect the amount of 9.4 Continue sampling until the desired color change has 9. remove the loading chute and 12.1 Report to the nearest 25 m·g when using a 0 to 1000 11. Place the ram into the chute and add the weight.3. and the sample size used. the weight.1 Weigh a sample of the test compound in accordance with 9.5. using the brass knife or wool. scale.2 When the bowl temperature has stabilized.2 The temperature of test.1.2 The temperature of test.1-11. position the quick-loading 11. 11.2.3 Mount the samples in a sequential time order.2 Using the point of maximum torque (fusion torque) pound from the bowl and blades using the brass knife or wool.3.2 Continue running until there is a sudden rise in the the torque curve indicates fusion. Clean the com.5. Place the ram into the chute and add the weight.1 Prepare the test compound in accordance with 9. 11.5. as zero time. 11. Stop the rotors and use a pair of a sample of the test compound.3. Confirm that the bowl has 10.1-10. Restart the chute on the roller-head mixer. the sample size.1. 10.4 Interpretation of Torque Rheometer Curve (Fig. the weight. Color-Hold Stability Test Method 12.1 Set the microprocessor for the desired temperature with 9.3. Trim the sample and return the excess to the mixing and add the weight. Copyright by ASTM Int'l (all rights reserved).5. 10.2 Prepare the test equipment in accordance with 9. discolor. stopping at the same point in time as 11.6 Report—Report the following information: 11. 11.5. and the time as determined in 11.3.5.3. remove the loading bowl.3.4 Run additional tests.1.6 Reassemble the mixing bowl and repeat 11.3. Thermal Stability Test Method reached the test temperature before starting. 11.5.3 Procedure: 11. 12. rotors. 11. as zero time. 11.5 Alternative Procedure: chute on the roller-head mixer and pour in the sample com. When min. Stop the mixer. Shear Stability Test Method 11. rotor revolutions per minute.3 Stop the mixer and open the bowl.3.1.5 for additional tests. Clean the com- note whether the torque is increasing or decreasing. of maximum torque (fusion torque) to the point of sudden torque increase.3 Clean the bowl and blades and reassemble the mixer.2.2. When with 9.5. When 10. Place the ram into the chute sample. With the mixer running. 12. remove the contents. 98 10.2 % 2.6 % Pooled Values 60. 13.1. prepared at the laboratories that tested them.7 % 20.3.86 3.4 % 1.3) is only denote a Newtonian material.65 10.72 10.4 % Parameter 2– Fusion Torque Temperature.2 % 13.43 9.2 1.8 % Material B 30.2 % Material B 47.24 7.33 5.6 % 3.4 When the mixer has stopped.58 26.1.4 0. Mean Level in Ascending Order Within Laboratories Between Laboratories Material Mean Level Sr r (r) SR R (R) Material B 171.90 2. materials.09 5.8 % Material A 35. data value. Point E (Newton-meters).72 22.9 0.0 1.98 3.95 2.2 5. Precision and Bias 12.1 % Material A 70.82 56.19 20.2 2.9 % Material C 85. Users of this method should apply the principles outlined in 13.2 % 2.15 3. plotted curve for analysis.79 2.8 % 0.82 58.53 2.06 2.1 The torque versus revolutions per minute plotted graph can be used in conjunction with the microprocessor 4 Supporting data giving results of the round robin have been filed at ASTM software to provide a shear-sensitivity index number. or both.5 % 2.91 10.53 7. D2538 − 02 (2010) TABLE 1 Round Robin Test Results Parameter 1– Fusion Torque.7 % Pooled Values 23.9 0.21 36.05 2. or stabilized torque.2 % 4.94 19.30 0.7 % Material E 56. Each sample was 13.61 5.41 15.0 % Pooled Values 33.3 % Parameter 3– End Torque. prepared at one source. 14.8 % 0. Mean Level in Ascending Order Within Laboratories Between Laboratories Material Mean Level Sr r (r) SR R (R) Material C 29.4 % 2. the shear sensitivity can be intended to present a meaningful way of considering the approximate estimated by the degree of arc.5 % Material D 174. the compound from the bowl and blades.65 7.1-12.36 37.8 % Material E 31.42 15.21 12.2 Technical Analysis: 13. all the samples were fusion curve which can be used to determine the fusion time.25 3.0 % Material E 181.61 21.97 13.1 Visual Analysis: electrically heated mixer/measuring head (3:2 gear ratio) to 13.38 3.45 20.9 % 12.5 0.0 0.5 0.6 % 0.2 % 13.2 The calculation programmed into the software is 12.2.78 13.97 23.3. A large arc or loop denotes more precision of this test method.86 51.4 % Material D 39.5 % 3. The International Headquarters.31 30.1.82 2. 4 .23 6. as these data apply only to the visual observation can be made to determine the relative shear materials tested in the round robin and are unlikely to be rigorously sensitivity between sample materials.2.92 7.47 6.5 for additional tests.2-14.78 2.91 2.5 % 12. but the individual specimens were fusion torque and melt.3 0.41 1.59 17. A acceptance or rejection of materials.53 11.5 0.71 1.1 Table 1 is based on a round robin4 conducted in 2001 12. The data in Table 1 should not be applied to shear-sensitive material than does a smaller arc or loop. representative of other lots.26 0.55 10. All laboratories 13. use the micropro. Copyright by ASTM Int'l (all rights reserved).6 7. formulations.08 21.58 1.85 2.1 % 4. For each material.25 2.8 % 0. in accordance with Practice E691.79 35.2.64 1.99 65.3 % Material C 23.57 7.15 22.21 9.1 % 3.6 0.3 Bearing in mind that a straight inclined line would NOTE 9—Caution: The explanation of r and R (14. software is programmed to give such a number.40 52.94 7.58 11. Clean shown in the Appendix X1.92 22.1 The first 10 min of the graph represents a standard process the samples.62 4.38 57.30 1.8 3.39 1.62 5. Interpretation of Torque Rheometer Results used a computerized torque rheometer and a single zone 13. conditions.3.14 4. using the brass knife or wool.1 % Parameter 4– Fusion Time (s). Mean Level in Ascending Order Within Laboratories Between Laboratories Material Mean Level Sr r (r) SR R (R) Material D 40.8 % Material A 25. Point X (Newton-meters).20 8.39 32. (degrees Celsius).6 8.3 % 0.21 6.3 % Material E 22.2 The torque versus revolutions per minute plot can be tested three times on two separate days yielding six points per used as a relative comparison of shear sensitivity.7 % Material A 183. Mean Level in Ascending Order Within Laboratories Between Laboratories Material Mean Level Sr r (r) SR R (R) Material B 17.7 % 9.3 % Pooled Values 179.08 3.4 % Material D 27.17 24.40 6.5 Reassemble the mixing bowl and repeat 14.1 1. Request RR:D20-1237.1 % 2. or labo- ratories. open the bowl.83 26.85 2.85 4.2 % Material C 188.38 3. 13.5 0.05 66.3 When the sample run is finished.18 7.3.79 2.6 1.6 % 2.92 2. Time at Fusion Minus Time at Load Torque.6 % 1.7 4.1 0.35 0. involving five rigid PVC dry blend compounds tested by ten laboratories.3.00 5. A higher index cessor to plot the torque versus revolutions per minute.3 2.97 2.6 0.41 6.7 1.73 3.78 6.73 13.52 4.48 1. Use the number denotes a more shear-sensitive material.9 % 7. 4 Data Interpretation (see Fig. NOTE 10—Symbols are defined as follows: Sr = within laboratory standard deviation 14.3): frictional heat (Fig.2-14.2.3 Calculation—Calculate the shear sensitivity of temperature can be obtained by using speed programming.3. PVC compounds.8Sr.1 The torque versus revolutions per minute curve at test X1.2 Reference Curve X1. obtained by the same operator using the same be valid for such data. Use pseudoplastics.2.1). Keywords laboratory shall be judged not equivalent if they differ by more 15. The principles of 14.2 Concept of r and R in Table 1—If Sr and SR have been 14.95) probability of being that were averages from testing one point for each test result. as shown in Fig.2 If the shear-sensitivity approaches zero (n ap- curve at 50 r/min as shown in Fig. % more than the R-value.1 If the shear-sensitivity index approaches one (pow- X1. X1.2.2. the first half of the torque versus revolutions per minute curve (0 to 50 r/min) in order to avoid melt temperature rise due to X1. fusion of PVC compound. rheometry APPENDIXES (Nonmandatory Information) X1. 14. between the reference revolutions per minute and the torque X1.3 Any judgment in accordance with 14. where r = 2. then: 14. R is the interval SR = between laboratory standard deviation representing the critical difference between two test results for R = between laboratory reproducibility. equipment on the same day in the same laboratory.2 calculated from a large enough body of data.4. r is the interval representing ity. X1. X1.3 would then material. where R = 2. correct. X1. % different equipment on different days.1 color stability.1 Torque Versus Revolutions Per Minute Curve FIG.2.2 Draw a reference line from the origin to the intercept erlaw index n approaches zero).2. heat stabil- than the r-value. and for test results would have an approximate 95 % (0. D2538 − 02 (2010) Practice E691 to generate data specific to their materials and laboratory (or the critical difference between two test results for the same between specific laboratories). measurement units two laboratories shall be judged not equivalent if they differ by (r) = within laboratory repeatability. CALCULATION OF SHEAR SENSITIVITY FIG.2 Reproducibility (R)—Two results obtained between r = within laboratory repeatability. X1. 5 . it is less shear sensitive.8SR. it is more shear sensitive.4.1 Repeatability (r)—Two results obtained within one 15. proaches one). S. measurement units the same material. X1.1 or 14.2. Copyright by ASTM Int'l (all rights reserved). obtained by a different operators using (R) = between laboratory reproducibility. X1. 3 Shear Sensitivity of Pseudoplastic Materials X2. X1. West Conshohocken. B = area of triangle.1 Suggested temperature/rotor speed combinations for PVC compounds are as follows: Compound Type Suggested Set Temperature/Rotor Speed Flexible Compound 140°C (284°F) @ 31 r/min Semirigid Compound 180°C (356°F) @ 50 r/min Rigid Compound 197°C (387°F) @ 60 r/min ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. 610-832-9555 (fax). PO Box C700. 100 Barr Harbor Drive. or service@astm. and the risk of infringement of such rights. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards. Copyright by ASTM Int'l (all rights reserved). Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the above address or at 610-832-9585 (phone). are entirely their own responsibility. SUGGESTED TEMPERATURE/ROTOR SPEED COMBINATIONS FOR PVC COMPOUNDS X2. either reapproved or withdrawn. Permission rights to photocopy the standard may also be secured from the ASTM website (www. FIG. or through the ASTM website (www. United States. This standard is copyrighted by ASTM International. PA 19428-2959. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised. which you may attend. D2538 − 02 (2010) where: A = area of arc.org/ COPYRIGHT/). 6 . at the address shown below. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters.org). Your comments will receive careful consideration at a meeting of the responsible technical committee.org (e-mail). and M = torque (m·g).astm.astm. Users of this standard are expressly advised that determination of the validity of any such patent rights.