1、Designation: D6265 09D6265 15Standard 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 If desired, mat
4、erials Materials isolated on a wire mesh filter can subsequently be identified by spectroscopic or otheranalytical 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
5、assumes the responsibility to verify 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
6、 SI units are to be regarded as standard.1.4 This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of theuser of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitat
7、ionsprior to use. For specific hazards statements, see Section 8.NOTE 2There is no known ISO equivalent to this practice.standard.2. Referenced Documents2.1 ASTM Standards:2D1238 Test Method for Melt Flow Rates of Thermoplastics by Extrusion PlastometerD1600 Terminology for Abbreviated Terms Relatin
8、g 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 System)3. Terminology3.1 The terminology used in this practice is in
9、 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 imperfections in the extruded productdue to contaminants and gels. Altho
10、ugh 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.5. Significance and Use5.1 Problems with extrusion and subsequent processing of the material ar
11、e caused, in part, by the presence of paper, metal, gels,incompatible polymers, or other extraneous contamination found in polymers.1 This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.95 on Recycled Plastics.Current edit
12、ion approved Sept. 1, 2009Oct. 1, 2015. Published September 2009October 2015. Originally approved in 1998. Last previous edition approved in 20032009as D6265 - 98D6265 - 09.(2003). DOI: 10.1520/D6265-09.10.1520/D6265-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactA
13、STM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard and is intended o
14、nly 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 appropriate. In all cases only the current ver
15、sionof 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. United States16. Apparatus6.1 Extruder, designed to
16、deliver a continuous supply 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
17、 mm2.6.1.2 Breaker Plate or 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 and a chart recorder.readout.6.1.4 Melt Thermocouple, installed before or after the screen pack and connected to a
18、chart recorder.pack.6.1.5 High Pressure Alarm and Rupture Disk.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) during screen changes.NOTE 3Although desirable, a swing gat
19、e is not always available on small extruders.6.2 Screens, The screen diameter is equal to the barrel diameter. Screen sizes of 60 mesh (0.251-mm opening), 100 mesh(0.152-mm opening), 200 mesh (0.076-mm opening), or 325 mesh (0.045-mm opening) have been found to be satisfactory.NOTE 4If the rate of p
20、ressure increase is impractical due to extremes in the contaminant level or size, screens with alternative mesh sizes can be used.6.3 Strip Chart Recorder, with a speed of 15 cm/h.6.3 Balance, capable of weighing with accuracy of 60.1 kg.6.4 Torque Wrench, with ratchet drive attachment.6.5 Thermally
21、 Insulated Gloves.Thermally Insulated Gloves.6.6 Spatulas and Scrapers, brass, assorted sizes for removing molten polymer from equipment.7. Materials7.1 Virgin Polymer, Virgin Polymer,free of gels and contaminants, for purging the extruder equipment.8. Hazards8.1 Hot polymer can cause serious burns.
22、 Do not stand in front of the extruder because air bubbles, excessive temperature orpressure can cause causes hot polymer to be expelled from the extruder die.8.2 Always wear Wear thermally insulated gloves when handling hot polymer or working directly with the heated areas of theextruder.9. Procedu
23、re9.1 Turn on the power to the extruder and turn on the feed throat cooling water.9.2 Set extruder temperature controllers to maintain the barrel at the appropriate temperature for the polymer (see Table 1).9.3 Wait at least a minimum of 30 min after achieving meltextruder temperature before startin
24、g the extruder.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 to permit compression of the screens.FIG. 1 Schematic Showing th
25、e Internal Sizing of the (Rod) DieD6265 1529.4 Insert a new screen pack using 60 (0.251 mm opening)-100 (0.152 mm opening) -60 mesh screens plus 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.
26、This helps keep the screens firmlyin place, insures the correct surface area of filter screw is actually used during the test, and simplifies 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
27、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 the 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
28、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 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 sampl
29、e 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 following sequence:9.9.1 Extruder, rod die, 325 mesh screen, 200 mesh screen (0.076 mm opening), 100 mesh screen (0.152 mm opening), 60 meshscreen (0.251 mm opening),
30、backing screens (60 mesh or higher), and the breaker plate.NOTE 7Referring to Fig. 3, the screen pack must have sufficient 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 10
31、0 rpm as quickly as possible while observing pressure and loadreadouts for any excessive increases. Start the chart recorder.9.11 Once the pressure has stabilized for at least a minimum of 5 min and the system is at the correct temperature, cut off theextrudate at the strip die and begin collection.
32、 Record the initial filter pressure (Pi) to the nearest 0.2 Mpa. If the pressure continuesto rise, but not stabilize, stop the extruder before attaining the maximum safe operating pressure for the equipment. Note and reportthe rate of pressure rise.9.12 Continue extruding the polymer monitoring the
33、filter pressure for 20 to 30 min or until 14 kg of polymer has been extruded.Record the filter pressure every 5 minutes (P(minutes) and at the end of the collection cycle (Pf) to the nearest 0.2 MPa.NOTE 1Drill 25 holes; use #60 drill.FIG. 2 Schematic of the Breaker PlateTABLE 1 Suggested Extruder T
34、emperaturesPolymer Extruder Temperature, CAcetals 190Acrylics 230Nylon 275Polycarbonate 300Polyethylene 200Poly(ethylene terephthalate) 280Polypropylene 230Polystyrene 200Poly(vinyl acetal) 150Styrene-acrylonitrile 225D6265 153NOTE 8After the filters are installed, carefully watch the filter back pr
35、essure 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 extrudate can be collected as a total mass and weighed after all resin has been extruded or the extrusion rate may be determined a
36、ndthe 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 flake), always purge the system with stabilized pellets before shutting down theextruder. Always return extruder drive to minimum rpm
37、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 duration of the shutdown.9.14 Disassemble the screen pack and save the 325 mesh screen. Scrape any excess polymer off the screen whi
38、le 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 used for the test,10.1.2 The initial (Pi), extrusion (Pminutes) and final (Pf) filter pressures or the rate of pressure rise if unab
39、le 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 or contamination on the screens.11. Keywords11.1 contamination; extruder filtration test; polyolefins; recycled plasticsNOTE 1Spli
40、t clamp not to scale.FIG. 3 Schematic of the Screen Pack AssemblyD6265 154SUMMARY OF CHANGESCommittee D20 has identified the location of selected changes to this standard since the last issue(D6265 - 98D6265 - 09(2003) that may impact the use of this standard. (September(October 1, 2009)2015)(1) Upd
41、ated ISO equivalency statement in accordance with Guide D4968.(2) Deleted references to Guide D5033 and replaced with Guide D7209 in subsections 2.1 and 3.1.(1) RemovedReworded 1.2non-mandatory, 4.1language, 6.1.3from, 4.16.1.4, 8.1, 8.2, 9.3, 9.8, 9.10, 9.11, and 6.110.1.2.(2) Expanded extruderRewo
42、rded 9.12 size to 18-64 mm barrel diameter inand added reporting filter pressures every five6.1.minutes.(3) RewordedDeleted 6.2.old 6.3.(4) AddedRenumbered Note 4old 6.4 6.7 to 6.3 6.6.(7) No mercury reference was found.ASTM International takes no position respecting the validity of any patent right
43、s 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 subject to revision at any t
44、ime 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 Headquarters. Your comments will
45、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 is copyrighted by ASTM
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