ASTM_D_6265_-_15.pdf

Designation:D626515Standard 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 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.The 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 wire mesh filter can be identifiedby spectroscopic or other analytical means.NOTE1Although 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 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 regarded 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 specific hazards statements,seeSection 8.NOTE2There is no known ISO equivalent to this standard.2.Referenced Documents2.1 ASTM Standards:2D1238 Test Method for Melt Flow Rates of Thermoplasticsby Extrusion PlastometerD1600 Terminology forAbbreviated Terms Relating to Plas-ticsD7209 Guide for Waste Reduction,Resource Recovery,andUse of Recycled Polymeric Materials and Products(With-drawn 2015)3IEEE/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 and Guide D7209.Units and symbolsare 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 absolute 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,gels,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 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 before thescreen pack and connected to digital readout.6.1.4 Melt Thermocouple,installed before or after thescreen pack.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 Oct.1,2015.Published October 2015.Originallyapproved in 1998.Last previous edition approved in 2009 as D6265-09.DOI:10.1520/D6265-15.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.*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 States1 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)duringscreen changes.NOTE3Although 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),or325 mesh(0.045-mm opening)have been found to be satisfac-tory.NOTE4If the rate of pressure increase is impractical due to extremesin the contaminant level or