1、Designation: D 6265 09Standard Practice forSeparation of Contaminants in Polymers Using an ExtruderFilter Test1This standard is issued under the fixed designation D 6265; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、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 unmoltenparticles, gels, and impurities contaminating a polymer sample.T
3、he 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 If desired, materials is
4、olated on a wire mesh filter cansubsequently be identified by spectroscopic or other analyticalmeans.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 respons
5、ibility to verifythe reproducibility 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 re
6、garded asstandard.1.4 This standard does not purport to address the safetyconcerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use. For spe
7、cific hazards statements, seeSection 8.NOTE 2There is no known ISO equivalent to this practice.2. Referenced Documents2.1 ASTM Standards:2D 1238 Test Method for Melt Flow Rates of Thermoplasticsby Extrusion PlastometerD 1600 Terminology for Abbreviated Terms Relating toPlasticsD 7209 Guide for Waste
8、 Reduction, Resource Recovery,and Use of Recycled Polymeric Materials and ProductsIEEE/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 D 1600 and Guide D 7209.
9、Units andsymbols are in accordance with Practice IEEE/ASTM SI-10.4. Summary of Practice4.1 This practice 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 absolu
10、te measurement of contami-nation level, using appropriate criteria, the rate of this pressurerise can 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,gel
11、s, incompatible polymers, or other extraneous contamina-tion found in polymers.6. Apparatus6.1 Extruder, 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.6.1.1 Int
12、ernal 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 before thescreen pack and connected to digital readout an
13、d a chartrecorder.6.1.4 Melt Thermocouple, installed before or after thescreen pack and connected to a chart recorder.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.95 on Recycled Plastics.Current edition approved Sep
14、t. 1, 2009. Published September 2009. Originallyapproved in 1998. Last previous edition approved in 2003 as D 6265 - 98(2003).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,
15、 refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.1.5 High Pressure Alarm and Rupture Disk.6.1.6 Split
16、 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) 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. Scre
17、en sizes of 60 mesh (0.251-mm opening), 100mesh (0.152-mm opening), 200 mesh (0.076-mm opening), or325 mesh (0.045-mm opening) have been found to be satisfac-tory.NOTE 4If the rate of pressure increase is impractical due to extremesin the contaminant level or size, screens with alternative mesh size
18、s can beused.6.3 Strip Chart Recorder, with a speed of 15 cm/h.6.4 Balance, capable of weighing with accuracy of 60.1 kg.6.5 Torque Wrench, with ratchet drive attachment.6.6 Thermally Insulated Gloves.6.7 Spatulas and Scrapers, brass, assorted sizes for remov-ing molten polymer from equipment.7. Mat
19、erials7.1 Virgin Polymer, free of gels and contaminants, forpurging the 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 can cause hot polymer to be expelled from theextruder die.8.2 Alw
20、ays wear thermally insulated gloves when handlinghot polymer or working directly 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 temperatu
21、re for the polymer (see Table1).9.3 Wait at least 30 min after achieving melt temperaturebefore 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 suffic
22、ient depth to prevent thebreaker plate from fully contacting the rod die. This helps keep the screensfirmly in place, insures the correct surface area of filter screw is actuallyused during the test, and simplifies disassembly.9.5 Close the split clamp and tighten to 6.9 kg-m (50 ft-lb)using a torqu
23、e wrench (this and other requirements 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 Adj
24、ust the screw speed to the 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
25、 at 80 rpm.NOTEA = 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 to permit compression of the screens.FIG. 1 Schematic Showing the Inte
26、rnal Sizing of the (Rod) DieNOTEDrill 25 holes; use #60 drill.FIG. 2 Schematic of the Breaker PlateTABLE 1 Suggested Extruder TemperaturesPolymer Extruder Temperature, CAcetals 190Acrylics 230Nylon 275Polycarbonate 300Polyethylene 200Poly(ethylene terephthalate) 280Polypropylene 230Polystyrene 200Po
27、ly(vinyl acetal) 150Styrene-acrylonitrile 225D62650929.8 Empty and refill the hopper with the test sample andpurge for 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, 200 mesh screen(0
28、.076 mm opening), 100 mesh screen (0.152 mm opening), 60mesh screen (0.251 mm opening), backing screens (60 mesh orhigher), and the breaker plate.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
29、size may be substituted.9.10 Start the extruder and bring it up to a screw speed of100 rpm as quickly as possible while observing pressure andload readouts for any excessive increases. Start the chartrecorder.9.11 Once the pressure has stabilized for at least 5 min andthe system is at the correct te
30、mperature, cut off the extrudate atthe strip die and begin collection. Record the filter pressure (Pi)to the nearest 0.2 Mpa. If the pressure continues to rise, but notstabilize, stop the extruder before attaining the maximum safeoperating pressure for the equipment. Note and report the rateof press
31、ure rise.9.12 Continue extruding the polymer monitoring the filterpressure for 20 to 30 min or until 14 kg of polymer has beenextruded. Record the filter pressure at the end of the collectioncycle (Pf) to the nearest 0.2 MPa.NOTE 8After the filters are installed, carefully watch the filter backpress
32、ure as the extrusion is restarted. If 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
33、 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, polyolefinflake), always purge the system with stabilized pellets before shuttingdown the extruder. Always return extruder drive to minimum rpm before
34、shutting down the extruder. To prevent 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
35、stillhot to avoid disturbing any residues 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) and final (Pf) pressures or the rate ofpressure rise if unable to obtain a stabilized pressure (see
36、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 or contamination on thescreens.11. Keywords11.1 contamination; extruder filtration test; polyolefins; re-cycled plasticsNOTESplit clamp not to scale.FIG. 3 Schematic of
37、the Screen Pack AssemblyD6265093SUMMARY OF CHANGESCommittee D20 has identified the location of selected changes to this standard since the last issue(D 6265 - 98(2003) that may impact the use of this standard. (September 1, 2009)(1) Updated ISO equivalency statement in accordance withGuide D 4968.(2
38、) Deleted references to Guide D 5033 and replaced withGuide D 7209 in subsections 2.1 and 3.1.(3) Removed non-mandatory language from 4.1and 6.1.(4) Expanded extruder size to 18-64 mm barrel diameter in6.1.(5) Reworded 6.2.(6) Added Note 4.(7) No mercury reference was found.ASTM International takes
39、no position respecting the validity 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 respo
40、nsibility.This standard is subject 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
41、 to ASTM International Headquarters. 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 a
42、ddress shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D6265094
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