1、Designation: D 5577 94 (Reapproved 2003)Standard Guide forTechniques to Separate and Identify Contaminants inRecycled Plastics1This standard is issued under the fixed designation D 5577; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisi
2、on, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide is intended to provide information on avail-able methods for the separation and classifica
3、tion of contami-nants such as moisture, incompatible polymers, metals, adhe-sives, glass, paper, wood, chemicals, and original-productresidues in recycled plastic flakes or pellets. Although nospecific methods for identification or characterization of foamproducts are included, foam products are not
4、 excluded fromthis guide. The methods presented apply to post-consumerplastics.1.2 For specific procedures existing as ASTM test methods,this guide only lists the appropriate reference. Where nocurrent ASTM standard exists, however, this guide givesprocedures for the separation or identification, or
5、 both, ofspecific contaminants. Appendix X1 lists the tests and thespecific contaminant addressed by each procedure.1.3 This guide does not include procedures to quantify thecontaminants unless this information is available in referencedASTM standards.1.4 This standard does not purport to address al
6、l of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE 1Although this guide references ISO standards, there is no
7、similar or equivalent ISO standard covering this topic.2. Referenced Documents2.1 ASTM Standards:D 789 Test Methods for Determination of Relative Viscos-ity, Melting Point, and Moisture Content of Polyamide(PA)2D 792 Test Methods for Specific Gravity (Relative Density)and Density of Plastics by Disp
8、lacement2D 883 Terminology Relating to Plastics2D 1003 Test Method for Haze and Luminous Transmittanceof Transparent Plastics2D 1193 Specification for Reagent Water3D 1238 Test Method for Flow Rates of Thermoplastics byExtrusion Plastometer2D 1457 Specification for Polytetrafluoroethylene (PTFE)Mold
9、ing and Extrusion Materials2D 1505 Test Method for Density of Plastics by the Density-Gradient Technique2D 1898 Practice for Sampling of Plastics2D 1925 Test Method for Yellowness Index of Plastics2D 3418 Test Method for Transition Temperatures of Poly-mers by Thermal Analysis4D 4019 Test Method for
10、 Moisture in Plastics by Coulomet-ric Regeneration of Phosphorus Pentoxide4D 5033 Guide for the Development of Standards Relating tothe Proper Use of Recycled Plastics5D 5227 Test Method for the Measurement of Hexane Ex-tractable Content of Polyolefins5E 169 Practices for General Techniques of Ultra
11、violet-Visible Quantitative Analysis6E 355 Practice for Gas Chromatography Terms and Rela-tionships6E 682 Practice for Liquid Chromatography Terms and Re-lationships6E 794 Test Method for Melting and Crystallization Tem-peratures by Thermal Analysis7E 1252 Practice for General Techniques for Qualita
12、tiveInfrared Analysis62.2 ISO Standards:8ISO 3451/1-1981 PlasticsDetermination of Ash; Part 1:General MethodsISO 1183-1987 Methods for Determining the Density andRelative Density of Noncellular Plastics3. Terminology3.1 This terminology used in this guide is in accordancewith Terminology D 883 and G
13、uide D 5033.1This guide is under the jurisdiction of ASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.95 on Recycled Plastics.Current edition approved January 10, 2003. Published March 2003. Originallyapproved in 1994. Last previous edition approved in 1994 as D 557
14、7 - 94.2Annual Book of ASTM Standards, Vol 08.01.3Annual Book of ASTM Standards, Vol 11.01.4Annual Book of ASTM Standards, Vol 08.02.5Annual Book of ASTM Standards, Vol 08.03.6Annual Book of ASTM Standards, Vol 14.01.7Annual Book of ASTM Standards, Vol 14.02.8Available from American National Standar
15、ds Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2 Definitions of Terms Specific to This Standard:3.2.1 chemicalsnonhazardous or hazardous materials (forexample, inse
16、cticides or herbicides) potentially used in contactwith plastic materials.3.2.2 glueadhesives used for labels or joining bottle parts(for example, ethylene-vinyl acetate).3.2.3 heavy metalsmetals heavier than sodium on theperiodic table (for example, lead, arsenic, cadmium, chro-mium, or copper).3.2
17、.4 heavy plasticunfilled polymers such as polystyrene,poly(ethylene terephthalate), and poly(vinyl chloride) andfilled materials with densities greater than 1.00 g/cm3.3.2.5 light plasticpolymers such as polyethylene andpolypropylene with densities less than 1.00 g/cm3.3.2.6 original-product residue
18、sresidues from anyoriginal-product contents of a plastic package (for example,milk, juice, or detergent).3.2.7 particlespiece of metal, glass, wood, paper, or otherdiscreetly shaped material equal to or larger than 0.1 mm2.3.2.8 specksany material equal to or less than 0.1 mm2.4. Summary of Guide4.1
19、 This guide provides details of several procedures used toseparate and classify contaminants including, but not limitedto, moisture, original product residues, incompatible plastic,metal, paper, glass, adhesives, and wood in recycled plasticflakes or pellets. This guide lists existing ASTM and ISOme
20、thods that can be used to characterize solid and some liquidcontaminants. In addition, this guide presents details of someindustry procedures for identification of contaminants. Appen-dix X1 provides information on quantitative aspects of some ofthese industry standards that can also be used to esti
21、mate theconcentration of various contaminants.5. Significance and Use5.1 Recycled plastic materials may contain incompatibleplastic or other undesirable contaminants that could affect theprocessing or quality, or both, of the plastic prepared for reuse.Techniques to separate and identify incompatibl
22、e plastics,moisture, chemicals, or original product residues, and solidcontaminants such as metals, paper, glass, and wood areessential to the processing of recycled plastic materials.5.2 This guide lists existing ASTM and ISO methods pluscurrently practiced industrial techniques for identification
23、andclassification of contaminants in recycled plastics flake orpellets.6. Sampling6.1 Unless otherwise stated, materials should be sampled inaccordance with the procedures described in Practice D 1898.Adequate statistical sampling should be considered as anacceptable alternative.7. Existing ASTM or
24、ISO Procedures7.1 Moisture:7.1.1 A coulometric method (Test Method D 4019), thestandard test method for haze (Test Method D 1003), KarlFisher titration (Test Method D 789), or a gravimetric proce-dure (13.6.1 of Specification D 1457) can be used to estimatethe moisture content of recycled plastic ma
25、terials.7.2 Visual Inspection and Product Uniformity:7.2.1 Color:7.2.1.1 Test Method D 1925 measures the yellowness indexof clear acrylic plastics and the haze and the luminoustransmittance procedure (Test Method D 1003) characterizesthe color of transparent unpigmented recycled plastic materi-als.
26、These tests are not readily applied to pigmented plasticsamples.NOTE 2Test Method D 1925 is currently being revised by ASTMSubcommittee D20.40 to address reproducibility and bias problems.7.2.2 Melt Flow for Product UniformityUniformity ofsome recycled plastic flakes or pellets can be estimated byme
27、asuring the flow rate of the material using an extrusionplastometer (Test Method D 1238).7.3 Density or Specific GravityThe displacement methodfor specific gravity or relative density (Test Method D 792) orthe density-gradient procedure for density (Test MethodD 1505) are useful techniques to determ
28、ine contamination ofrecycled plastic flakes or pellet samples with one or more otherpolymers.NOTE 3Test Method D 1505 uses relatively small test specimens, soit may not be applicable for analysis of nonhomogeneous recycled plasticmaterials.7.4 Inorganic Contaminants:7.4.1 An ash test, such as ISO 34
29、51/1, or the muffle-furnacetechniques currently being evaluated within ASTM Subcom-mittee D20.70 (project designation X70-8702) can be used toestimate the inorganic filler content of recycled plastic flake orpellets.NOTE 4Some volatile metals may be lost using the test indicated in7.4.1. ASTM Subcom
30、mittee D20.70 is currently developing a test method(project X70-9201) for metals, including heavy metals, that will includesample-preparation techniques to minimize the loss of volatile metalsprior to analysis by X-ray fluorescence or spectroscopic techniques.7.4.2 Ferrous (iron) contaminants can be
31、 removed with amagnet and aluminum contaminants are separated from plasticmaterials using density procedures in accordance with 8.3.7.5 Thermal Analysis:7.5.1 Since most polymers exhibit unique temperatures formelting or other phase transitions, measurement of thesetransition temperatures (Test Meth
32、od D 3418) or the meltingand crystallization temperatures (Test Method E 794) of asample may provide useful information regarding the identityof polymeric components present in a recycled plastic material.7.5.2 Both Test Methods D 3418 and E 794 involve thermalgravimetric analysis (TGA) or different
33、ial scanning calorim-etry (DSC). These techniques utilize small samples (5 to 15mg), so they may not be practical for use in characterization ofpotentially nonhomogeneous recycled plastic materials.7.6 Infrared AnalysisQualitative infrared analysis usingthe techniques of Practice E 1252 can be used
34、to identifypolymeric, chemical, and, in some cases, inorganic compo-nents of recycled plastic materials. Sample size considerationsindicated in 7.5.2 may also apply to preparation of samples forinfrared analysis.D 5577 94 (2003)27.7 Chromatographic AnalysisThe principles of gas chro-matography, desc
35、ribed in Practice E 355, and liquid chroma-tography, described in Practice E 682, are useful for separationand classification of chemical contaminants or residues fromoriginal-use contents of plastic packages.8. Additional Industrial Procedures8.1 Specimen Preparation:8.1.1 Using standard injection
36、molding equipment, preparehomogenized sample plaques.8.1.2 Plaques, or slices from plaques prepared in 8.1.1, canbe used for differential scanning calorimetry (DSC), infraredanalysis, and other test procedures requiring small, homoge-neous specimens.8.2 Visible Inspection Procedures:8.2.1 Inspection
37、 Table for Large, Visible Contaminants:8.2.1.1 Using a laboratory spatula, spread 450 6 20gofrecycled plastic flakes or pellets on a clean, white inspectiontable.8.2.1.2 Without the benefit of magnification, describe thetypes of individual contaminant “particles” as defined in 3.2.7,then using 103 m
38、agnification, describe the “specks” as definedin 3.2.8.8.2.1.3 Thermal techniques (see 7.5) and infrared analysis(see 7.6) can be used to identify some of the isolated contami-nants.NOTE 5To obtain a quantitative estimate of the contaminants, thesecontaminants can be removed and weighed, but there i
39、s not existingprecision and bias data related to this estimated contaminant concentra-tions in recycled plastics.8.2.2 Inspection of Molded Specimens or Plaques:8.2.2.1 Weigh 4 to5gofdryplastic flake on to a polyestersheet or aluminum foil in a 15.2 by 15.2 by 0.013-cm mold.Cover with another sheet
40、of polyester film or aluminum foil,then adjust the press temperature to at least 10C above themelting temperature of the bulk of the test material.8.2.2.2 Press a plaque from the recycled plastic sample.Remove the plaque from the press and cool.8.2.2.3 Visually examine the test plaque within a 10-cm
41、2area using a fluorescent-light table. For comparison, repeat8.3.1 and 8.3.2 with a portion of virgin resin representing thebulk of the test material (for example, poly(ethylene tereph-thalate) (PET) if you are interested in contaminants in recycledPET).NOTE 6The presence of glue contamination is in
42、dicated by bondingof the plastic to the polyester sheet used as a release material duringmolding of the plaque.NOTE 7An alternative procedure for poly(ethylene terephthalate)involves melting pellets for 10 min at 275C in an aluminum pan. Thismelt is rapidly quenched in ice water to prevent crystalli
43、zation and theresulting disk or plaque is visually inspected for contaminants and blackspecks by comparison with a control disk or plaque prepared from virginPET. In this case, black specks are attributed to degraded paper, adhesives,poly(vinyl chloride), or other contaminants in the poly(ethylene t
44、ereph-thalate).8.3 Separations Based on Density:8.3.1 Water-Density Separation:8.3.1.1 Fill a clean plastic container with 2 L of clean water.Add sufficient nonionic surfactant to make a 2 % (weight/volume) solution and mix thoroughly.NOTE 8Acknowledging that water quality varies from one part of th
45、ecountry to another, minimum water quality for this test includes propertiesof Type III grade reagent water as defined in Specification D 1193.NOTE 9Air pockets within flake material may cause the material tofold back on itself. The surfactant (for example, Triton X-1009) helpseliminate this problem
46、 with plastic flakes.8.3.1.2 Obtain a representative sample of recycled plasticflakes (see 6.1) and weigh 100 6 10 g into a clean, dry plasticcontainer.NOTE 10The sample should be free of particles identified by aprocedure such as that described in 8.1.8.3.1.3 Add the surfactant solution from 8.3.1.
47、1 to thesample container and mix well with a spatula. Allow solids tosettle for at least 5 min.8.3.1.4 Skim light plastic and any contaminants (for ex-ample, paper) from the top of the water using a small kitchenstrainer. Transfer these materials to a larger strainer and rinsewith water to remove re
48、sidual surfactant.8.3.1.5 Pour the remaining contents from the sample con-tainer (see 8.3.1.4) through another large strainer and washthese heavier materials with water to remove residual surfac-tant.8.3.1.6 If desired, these collected heavy materials are driedand characterized by thermal (see 7.5)
49、or infrared (see 7.6)techniques.8.3.2 Propanol/Water Density Separation:8.3.2.1 Add 1840 mL of 2-propanol and 1660 mL of water(drinking, distilled, or deionized) to a 4-L plastic bottle. Mixwell to provide a solution containing 52 % (volume:volume)2-propanol in water.8.3.2.2 Pour 200 mL of the solution from 8.3.2.1 into a500-mL graduated cylinder and measure the specific gravity ofthis solution with a hydrometer. The specific gravity should bebetween 0.914 and 0.917. If not, add small amounts of2-propanol or water to the solution from 8.3.2.1 to bring thespecific
