1、Designation: D6265 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 year of la
2、st 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 unmoltenparticles, gels, and impurities contaminating a polymer sample.The
3、 procedure may be used to remove gels and incompatiblematerials that may cause imperfections in the final extrudedproduct. Under pressure, most gels will break up or deform andpass through a wire mesh filter, however high molecular weightgels may not break up or deform.1.2 Materials isolated on a wi
4、re mesh filter can be identifiedby spectroscopic or other analytical means.NOTE 1Although not presented as a quantitative method, the proce-dure presented in this practice may be used to provide quantitative resultsat the discretion of the user. The user assumes the responsibility to verifythe repro
5、ducibility of quantitative results. Detection limit depends on themesh size of the filter screen, but the procedure is generally applicable tothe separation of immiscible contaminants present at concentrationsgreater than 0.1 %.1.3 The values stated in SI units are to be regarded asstandard.1.4 This
6、 standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.For spe
7、cific hazards statements, see Section 8NOTE 2There is no known ISO equivalent to this standard.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Sta
8、ndards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1238 Test Method for Melt Flow Rates of Thermoplasticsby Extrusion PlastometerD1600 Terminology forAbbreviated Terms Relating to Plas-tics
9、IEEE/ASTM SI-10 Practice for Use of the InternationalSystem of Units (SI) (the Modernized Metric System)3. Terminology3.1 The terminology used in this practice is in accordancewith Terminology D1600. Units and symbols are in accordancewith Practice IEEE/ASTM SI-10.4. Summary of Practice4.1 This prac
10、tice determines the relative contaminationlevel that can cause undesirable imperfections in the extrudedproduct due to contaminants and gels. Although this practice isnot designed to provide an absolute measurement of contami-nation level, using appropriate criteria, the rate of this pressurerise ca
11、n be correlated to the relative contamination level.5. Significance and Use5.1 Problems with extrusion and subsequent processing ofthe material are caused, in part, by the presence of paper, metal,gels, incompatible polymers, or other extraneous contamina-tion found in polymers.6. Apparatus6.1 Extru
12、der, designed to deliver a continuous supply ofmolten resin to a filter at a uniform rate with good temperaturecontrol. Extruders with 18 to 64-mm diameters have beenfound to be satisfactory.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility
13、 of Subcommittee D20.95 on Recycled Plastics.Current edition approved Dec. 1, 2017. Published January 2018. Originallyapproved in 1998. Last previous edition approved in 2015 as D6265 - 15. DOI:10.1520/D6265-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Cust
14、omer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken,
15、PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization
16、 Technical Barriers to Trade (TBT) Committee.16.1.1 Internal Rod Die, to fix the filter area. Fig. 1 shows atypical 6.4 mm diameter die that gives a filter area of 12.45mm2.6.1.2 Breaker Plate or Screen HolderA typical configu-ration is shown in Fig. 2.6.1.3 Pressure Transducer, installed in-line be
17、fore thescreen pack and connected to digital readout.6.1.4 Melt Thermocouple, installed before or after thescreen pack.6.1.5 High Pressure Alarm and Rupture Disk.6.1.6 Split Clamp, to permit ready access to the screens,sizing die, and breaker plate.6.1.7 Swing Gate, to support the split clamp (6.1.6
18、) duringscreen changes.NOTE 3Although desirable, a swing gate is not always available onsmall extruders.6.2 Screens, The screen diameter is equal to the barreldiameter. Screen sizes of 60 mesh (0.251-mm opening), 100mesh (0.152-mm opening), 200 mesh (0.076-mm opening),325 mesh (0.045-mm opening) or
19、finer have been found to besatisfactory.NOTE 4If the rate of pressure increase is impractical due to extremesin the contaminant level or size, screens with alternative mesh sizes can beused.6.3 Balance, capable of weighing with accuracy of 60.1gms.6.4 Torque Wrench, with ratchet drive attachment.6.5
20、 Thermally Insulated Gloves.6.6 Spatulas and Scrapers, brass, assorted sizes for remov-ing molten polymer from equipment.6.7 Recording/monitoring device, to monitor and recordpressure build-up and other extruder properties.7. Materials7.1 Virgin Polymer, free of gels and contaminants, forpurging the
21、 extruder equipment.8. Hazards8.1 Hot polymer can cause serious burns. Do not stand infront of the extruder because air bubbles, excessive tempera-ture or pressure causes hot polymer to be expelled from theextruder die.8.2 Wear thermally insulated gloves when handling hotpolymer or working directly
22、with the heated areas of theextruder.9. Procedure9.1 Turn on the power to the extruder and turn on the feedthroat cooling water.9.2 Set extruder temperature controllers to maintain thebarrel at the appropriate temperature for the polymer (see Table1).9.3 Wait a minimum of 30 min after achieving extr
23、udertemperature 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 plus the backingscreens for the extruder purge.NOTE 5The screen pack must have sufficient depth to prevent thebreaker plate from fully contacting the rod die.
24、 This helps keep the screensfirmly in place, insures the correct surface area of filter screw is actuallyused during the test, and simplifies disassembly.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 pac
25、kshall exceed the depth of the screen-retaining recess ofthe breaker plate to permit compression of the screens.FIG. 1 Schematic Showing the Internal Sizing of the (Rod) DieNOTE 1Drill 25 holes; use #60 drill.FIG. 2 Schematic of the Breaker PlateTABLE 1 Suggested Extruder TemperaturesPolymer Extrude
26、r Temperature, CAcetals 190Acrylics 230Nylon 275Polycarbonate 300Polyethylene 200Poly(ethylene terephthalate) 280Polypropylene 230Polystyrene 200Poly(vinyl acetal) 150Styrene-acrylonitrile 225D6265 1729.5 Close the split clamp and tighten to 6.9 kg-m (50 ft-lb)using a torque wrench (this and other r
27、equirements may varydepending on the extruder model).NOTE 6Allow the breaker plate and rod die to heat up for anadditional 5 min to melt any residual solidified polymer before starting theextruder.9.6 Charge the hopper with 14 kg virgin polymer and startthe extruder.9.7 Adjust the screw speed to the
28、 desired setting and purgethe system with virgin polymer.9.7.1 For startup after more than 4 hours of non-use, purge20 min at 10 to 20 rpm followed by 5 to 8 min at 100 rpm.9.7.2 For systems with less than4hofnon-use, purge 10 to15 min at 10 to 20 rpm followed by 3 to 4 min at 80 rpm.9.8 Empty and r
29、efill the hopper with the test sample andpurge for a minimum of 5 min at 40 to 60 rpm.9.9 Shut down the extruder and immediately change thescreen pack assembly to the following sequence:9.9.1 Extruder, rod die, 325 mesh screen (0.045 mmopening), 200 mesh screen (0.076 mm opening), 100 meshscreen (0.
30、152 mm opening), 60 mesh screen (0.251 mmopening), backing screens (60 mesh or higher), and the breakerplate.NOTE 7Referring to Fig. 3, the screen pack must have sufficient depthto prevent the breaker plate from fully contacting the rod die. Screens ofother mesh size may be substituted.9.10 Start th
31、e extruder and bring it up to a screw speed of100 rpm as quickly as possible while observing pressure andload readouts for any excessive increases.9.11 Once the pressure has stabilized for a minimum of 5min and the system is at the correct temperature, cut off theextrudate at the strip die and begin
32、 collection. Record the initialfilter pressure (Pi) to the nearest 0.2 Mpa. If the pressurecontinues to rise, but not stabilize, stop the extruder beforeattaining the maximum safe operating pressure for the equip-ment. Note and report the rate of pressure rise.9.12 Continue extruding the polymer mon
33、itoring the filterpressure until 14 kg of polymer has been extruded. Record thefilter pressure every 5 minutes (P(minutes) and at the end of thecollection cycle (Pf) to the nearest 0.2 MPa.NOTE 8After the filters are installed, carefully watch the filter backpressure as the extrusion is restarted. I
34、f a rapid pressure rise occurs, stopthe extrusion before exceeding the maximum safe operating pressure forthe equipment.NOTE 9The extrudate can be collected as a total mass and weighedafter all resin has been extruded or the extrusion rate may be determinedand the filtration continued for the time r
35、equired to filter 15 kg of resin.9.13 Shut down the extruder.NOTE 10If running unstabilized polymer (for example, polyolefinflake), always purge the system with stabilized pellets before shuttingdown the extruder. Always return extruder drive to minimum rpm beforeshutting down the extruder. To preve
36、nt excessive degradation of polymerleft in the extruder, turn down the temperatures or turn off all heatersdepending on the duration of the shutdown.9.14 Disassemble the screen pack and save the 325 meshscreen. Scrape any excess polymer off the screen while it is stillhot to avoid disturbing any res
37、idues and to make the residuemore visible.10. Report10.1 Report the following information:10.1.1 The mesh size of screens used 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 astabilized pressure (see 9.11),NO
38、TE 1Split clamp not to scale.FIG. 3 Schematic of the Screen Pack AssemblyD6265 17310.1.3 The extruder barrel temperature,10.1.4 The elapsed time for operating the extruder, and10.1.5 The presence of residue or contamination on thescreens.11. Keywords11.1 contamination; extruder filtration test; poly
39、olefins; re-cycled plasticsSUMMARY OF CHANGESCommittee D20 has identified the location of selected changes to this standard since the last issue (D6265 - 15)that may impact the use of this standard. (December 1, 2017)(1) Section 2: Removed D7209 reference.(2) Reworded 3.1; removed D7209 reference.(3
40、) Reworded 6.2.(4) Reworded 6.3; changed 60.1 kg to 60.1 gms.(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 validity of any patent rights asserted in connection with any item mentionedin this s
41、tandard. 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 subject to revision at any time by the responsible technical committee and must be re
42、viewed 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 Headquarters. Your comments will receive careful consideration at a meeting of therespons
43、ible 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 is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West
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