1、Designation: D6265 15D6265 17Standard Practice forSeparation of Contaminants in Polymers Using an ExtruderFilter Test1This standard is issued under the fixed designation D6265; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar 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. Scope*1.1 This practice covers a means to separate the unmolten particles, gels, and impurities contaminating a polymer s
3、ample. Theprocedure may be used to remove gels and incompatible materials that may cause imperfections in the final extruded product.Under pressure, most gels will break up or deform and pass through a wire mesh filter, however high molecular weight gels maynot break up or deform.1.2 Materials isola
4、ted on a wire mesh filter can be identified by spectroscopic or other analytical means.NOTE 1Although not presented as a quantitative method, the procedure presented in this practice may be used to provide quantitative results at thediscretion of the user. The user assumes the responsibility to veri
5、fy the reproducibility of quantitative results. Detection limit depends on the mesh sizeof the filter screen, but the procedure is generally applicable to the separation of immiscible contaminants present at concentrations greater than 0.1 %.1.3 The values stated in SI units are to be regarded as st
6、andard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limita
7、tions prior to use. For specific hazards statements, see Section 8.NOTE 2There is no known ISO equivalent to this standard.NOTE 2There is no known ISO equivalent to this standard.1.5 This international standard was developed in accordance with internationally recognized principles on standardization
8、established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1238 Test Method for Melt Flow Rates of Thermoplastics by
9、 Extrusion PlastometerD1600 Terminology for Abbreviated Terms Relating to PlasticsD7209 Guide for Waste Reduction, Resource Recovery, and Use of Recycled Polymeric Materials and Products (Withdrawn2015)3IEEE/ASTM SI-10 Practice for Use of the International System of Units (SI) (the Modernized Metric
10、 System)3. Terminology3.1 The terminology used in this practice is in accordance with Terminology D1600 and Guide D7209. Units and symbols arein accordance with Practice IEEE/ASTM SI-10.4. Summary of Practice4.1 This practice determines the relative contamination level that can cause undesirable imp
11、erfections in the extruded productdue to contaminants and gels. Although this practice is not designed to provide an absolute measurement of contamination level,using appropriate criteria, the rate of this pressure rise can be correlated to the relative contamination level.1 This test method is unde
12、r the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.95 on Recycled Plastics.Current edition approved Oct. 1, 2015Dec. 1, 2017. Published October 2015January 2018. Originally approved in 1998. Last previous edition approved in 20092015 asD6265 - 0
13、9.D6265 - 15. DOI: 10.1520/D6265-15.10.1520/D6265-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This doc
14、ument is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as
15、 appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. Unite
16、d States15. Significance and Use5.1 Problems with extrusion and subsequent processing of the material are caused, in part, by the presence of paper, metal, gels,incompatible polymers, or other extraneous contamination found in polymers.6. Apparatus6.1 Extruder, designed to deliver a continuous suppl
17、y of molten resin to a filter at a uniform rate with good temperature control.Extruders with 18 to 64-mm diameters have been found to be satisfactory.6.1.1 Internal Rod Die, to fix the filter area. Fig. 1 shows a typical 6.4 mm diameter die that gives a filter area of 12.45 mm2.6.1.2 Breaker Plate o
18、r Screen HolderA typical configuration is shown in Fig. 2.6.1.3 Pressure Transducer, installed in-line before the screen pack and connected to digital readout.6.1.4 Melt Thermocouple, installed before or after the screen pack.6.1.5 High Pressure Alarm and Rupture Disk.6.1.6 Split Clamp, to permit re
19、ady access to the screens, sizing die, and breaker plate.6.1.7 Swing Gate, to support the split clamp (6.1.6) during screen changes.NOTE 3Although desirable, a swing gate is not always available on small extruders.6.2 Screens, The screen diameter is equal to the barrel diameter. Screen sizes of 60 m
20、esh (0.251-mm opening), 100 mesh(0.152-mm opening), 200 mesh (0.076-mm opening), or 325 mesh (0.045-mm opening) or finer have been found to be satisfactory.NOTE 4If the rate of pressure increase is impractical due to extremes in the contaminant level or size, screens with alternative mesh sizes can
21、be used.6.3 Balance, capable of weighing with accuracy of 60.1 kg.gms.6.4 Torque Wrench, with ratchet drive attachment.6.5 Thermally Insulated Gloves.6.6 Spatulas and Scrapers, brass, assorted sizes for removing molten polymer from equipment.6.7 Recording/monitoring device, to monitor and record pre
22、ssure build-up and other extruder properties.7. Materials7.1 Virgin Polymer, free of gels and contaminants, for purging the extruder equipment.8. Hazards8.1 Hot polymer can cause serious burns. Do not stand in front of the extruder because air bubbles, excessive temperature orpressure causes hot pol
23、ymer to be expelled from the extruder die.8.2 Wear thermally insulated gloves when handling hot polymer or working directly with the heated areas of the extruder.9. Procedure9.1 Turn on the power to the extruder and turn on the feed throat cooling water.9.2 Set extruder temperature controllers to ma
24、intain the barrel at the appropriate temperature for the polymer (see Table 1).NOTE 1A = 0.250 in.,B = 0.0625 in.,C = same diameter as extruder barrel, andD = dimension that when added to the total thickness of the screen packshall exceed the depth of the screen-retaining recess ofthe breaker plate
25、to permit compression of the screens.FIG. 1 Schematic Showing the Internal Sizing of the (Rod) DieD6265 1729.3 Wait a minimum of 30 min after achieving extruder temperature before starting the extruder.9.4 Insert a new screen pack using 60 (0.251 mm opening)-100 (0.152 mm opening) -60 mesh screens p
26、lus the backing screensfor the extruder purge.NOTE 5The screen pack must have sufficient depth to prevent the breaker plate from fully contacting the rod die. This helps keep the screens firmlyin place, insures the correct surface area of filter screw is actually used during the test, and simplifies
27、 disassembly.9.5 Close the split clamp and tighten to 6.9 kg-m (50 ft-lb) using a torque wrench (this and other requirements may varydepending on the extruder model).NOTE 6Allow the breaker plate and rod die to heat up for an additional 5 min to melt any residual solidified polymer before starting t
28、he extruder.9.6 Charge the hopper with 14 kg virgin polymer and start the extruder.9.7 Adjust the screw speed to the desired setting and purge the system with virgin polymer.9.7.1 For startup after more than 4 hours of non-use, purge 20 min at 10 to 20 rpm followed by 5 to 8 min at 100 rpm.9.7.2 For
29、 systems with less than 4 h of non-use, purge 10 to 15 min at 10 to 20 rpm followed by 3 to 4 min at 80 rpm.9.8 Empty and refill the hopper with the test sample and purge for a minimum of 5 min at 40 to 60 rpm.9.9 Shut down the extruder and immediately change the screen pack assembly to the followin
30、g sequence:9.9.1 Extruder, rod die, 325 mesh screen, screen (0.045 mm opening), 200 mesh screen (0.076 mm opening), 100 mesh screen(0.152 mm opening), 60 mesh screen (0.251 mm opening), backing screens (60 mesh or higher), and the breaker plate.NOTE 7Referring to Fig. 3, the screen pack must have su
31、fficient depth to prevent the breaker plate from fully contacting the rod die. Screens of othermesh size may be substituted.9.10 Start the extruder and bring it up to a screw speed of 100 rpm as quickly as possible while observing pressure and loadreadouts for any excessive increases.9.11 Once the p
32、ressure has stabilized for a minimum of 5 min and the system is at the correct temperature, cut off the extrudateat the strip die and begin collection. Record the initial filter pressure (Pi) to the nearest 0.2 Mpa. If the pressure continues to rise,but not stabilize, stop the extruder before attain
33、ing the maximum safe operating pressure for the equipment. Note and report therate of pressure rise.NOTE 1Drill 25 holes; use #60 drill.FIG. 2 Schematic of the Breaker PlateTABLE 1 Suggested Extruder TemperaturesPolymer Extruder Temperature, CAcetals 190Acrylics 230Nylon 275Polycarbonate 300Polyethy
34、lene 200Poly(ethylene terephthalate) 280Polypropylene 230Polystyrene 200Poly(vinyl acetal) 150Styrene-acrylonitrile 225D6265 1739.12 Continue extruding the polymer monitoring the filter pressure until 14 kg of polymer has been extruded. Record the filterpressure every 5 minutes (P(minutes) and at th
35、e end of the collection cycle (Pf) to the nearest 0.2 MPa.NOTE 8After the filters are installed, carefully watch the filter back pressure as the extrusion is restarted. If a rapid pressure rise occurs, stop theextrusion before exceeding the maximum safe operating pressure for the equipment.NOTE 9The
36、 extrudate can be collected as a total mass and weighed after all resin has been extruded or the extrusion rate may be determined andthe filtration continued for the time required to filter 15 kg of resin.9.13 Shut down the extruder.NOTE 10If running unstabilized polymer (for example, polyolefin fla
37、ke), always purge the system with stabilized pellets before shutting down theextruder. Always return extruder drive to minimum rpm before shutting down the extruder. To prevent excessive degradation of polymer left in theextruder, turn down the temperatures or turn off all heaters depending on the d
38、uration of the shutdown.9.14 Disassemble the screen pack and save the 325 mesh screen. Scrape any excess polymer off the screen while it is still hotto avoid disturbing any residues and to make the residue more visible.10. Report10.1 Report the following information:10.1.1 The mesh size of screens u
39、sed for the test,10.1.2 The initial (Pi), extrusion (Pminutes) and final (Pf) filter pressures or the rate of pressure rise if unable to obtain a stabilizedpressure (see 9.11),10.1.3 The extruder barrel temperature,10.1.4 The elapsed time for operating the extruder, and10.1.5 The presence of residue
40、 or contamination on the screens.11. Keywords11.1 contamination; extruder filtration test; polyolefins; recycled plasticsNOTE 1Split clamp not to scale.FIG. 3 Schematic of the Screen Pack AssemblyD6265 174SUMMARY OF CHANGESCommittee D20 has identified the location of selected changes to this standar
41、d since the last issue(D6265 - 09D6265 - 15) that may impact the use of this standard. (October(December 1, 2015)2017)(1) RewordedSection 1.2,2: 4.1,Removed 6.1.3,D7209 6.1.4, reference.8.1, 8.2, 9.3, 9.8, 9.10, 9.11, and 10.1.2.(2) Reworded 9.12 and added reporting filter pressures every five minut
42、es.3.1; removed D7209 reference.(3) Deleted old 6.3.Reworded 6.2.(4) Renumbered old 6.4 6.7Reworded 6.3; changed 60.1 kg to 6.3 60.1 gms.6.6.(5) Added 6.7; recording/monitoring device.(6) Reworded 9.9.1; added opening size for 325 mesh screen.ASTM International takes no position respecting the valid
43、ity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subje
44、ct to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarte
45、rs. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard
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