1、Designation: D5991 17Standard Practice forSeparation and Identification of Poly(Vinyl Chloride) (PVC)Contamination in Poly(Ethylene Terephthalate) (PET) Flake1This standard is issued under the fixed designation D5991; the number immediately following the designation indicates the year oforiginal ado
2、ption 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 four procedures for separation andqualitative ide
3、ntification of poly(vinyl chloride) (PVC) con-tamination in poly(ethylene terephthalate) (PET) flakes.NOTE 1Although not presented as a quantitative method, procedurespresented in this practice may be used to provide quantitative results at thediscretion of the user. The user assumes the responsibil
4、ity to verify thereproducibility of quantitative results. Data from an independent sourcesuggest a PVC detection level of 200 ppm (w/w) based on an originalsample weight of 454 g.1.2 Procedure A is based on different fluorescence of PVCand PET when these polymers are exposed to ultraviolet (UV)light
5、.1.3 Procedure B is an oven test based upon the charring ofPVC when it is heated in air at 235C.1.4 Procedures C and D are dye tests based on differentialstaining of PVC and PET.NOTE 2Other polymers (for example, PETG) also absorb the stain orbrightener. Such interferences will result in false posit
6、ive identification ofPVC as the contaminant.1.5 This 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 applicab
7、ility of regulatory limitations prior to use.For specific hazards see Section 8.NOTE 3There is no known ISO equivalent to this standard.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principle
8、s for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1600 Terminology forAbbreviated Terms Relating to Plas-ticsIEEE/ASTM SI-10 American National Stan
9、dard for Use ofthe International System of Units (SI): The Modern MetricSystem3. Terminology3.1 The terminology used in this practice is in accordancewith Terminology D1600. Units and symbols are in accordancewith IEEE/ASTM SI-10.3.2 Definitions of Terms Specific to This Standard:3.2.1 light materia
10、l, npaper, polymers such as polyethyl-ene and polypropylene, and other materials with densities lessthan 1.00 g/cm3.4. Summary of Practice4.1 For the Beilstein Test, chlorine-containing materialsheated in a flame in contact with a copper wire produce acharacteristic green flame.4.2 With Procedure A,
11、 a known amount of PET flakes isexposed to ultraviolet radiation. PET normally fluoresces witha blue or violet color. Flakes fluorescing with different colorsare removed, weighed, and identified as PVC if they burn witha bright green flame when heated on a copper wire.4.3 With Procedure B, PET flake
12、s are heated in an ovenmaintained at 235 6 5C. After a minimum of 45 min, theflakes are visually examined with removal and subsequentweighing of black, charred pieces. Pieces are confirmed asPVC using the same flame test mentioned in 4.1.4.4 With Procedure C, PET flakes are soaked in a blueacetone d
13、ye solution that preferentially stains any PVC flakes.These flakes are visually identified and subsequently removed,and weighed. The identification of PVC flakes is confirmedwith the flame test.1This practice is under the jurisdiction ofASTM Committee D20 on Plastics andis the direct responsibility
14、of Subcommittee D20.95 on Recycled Plastics.Current edition approved Dec. 1, 2017. Published January 2018. Originallyapproved in 1996. Last previous edition approved in 2015 as D5991 - 15. DOI:10.1520/D5991-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Custo
15、mer 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, P
16、A 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
17、Technical Barriers to Trade (TBT) Committee.14.5 With Procedure D, PET flakes are heated with anaqueous solution containing an optical brightener that alsopreferentially stains the PVC flakes. The flakes are sorted underUV light in a dark room with removal and subsequentweighing of any blue fluoresc
18、ing PVC flakes.5. Significance and Use5.1 Presence of even low concentrations of PVC in recycledPET flakes results in equipment corrosion problems duringprocessing. The PVC contamination level shall dictate themarket for use of the recycled polymer in secondary products.Procedures presented in this
19、practice are used to identify thePVC contamination in recycled PET flakes.NOTE 4These procedures may also be used to estimate the concen-tration of PVC contamination.6. Apparatus6.1 Procedure A:6.1.1 Bright Aluminum Tray, shallow depth (0.75 cm).6.1.2 Light Fixture, equipped with GE F40/BLB, orequiv
20、alent, black light bulbs.6.1.3 Ultraviolet Shield Glasses.6.1.4 Tweezers.6.2 Procedure B:6.2.1 Circulating or Forced-Air Oven, equipped with atemperature readout device for the range of 230 to 240C.6.2.2 Baking Trays, 14 by 20 by 3 cm.6.2.3 Tweezers.6.2.4 Thermally Insulated Gloves, or equivalent.6.
21、3 Procedure C:6.3.1 Measuring Cup, 1.5 L.6.3.2 Plastic Stretch or Cling Wrap.6.3.3 Paper Towels, newspaper, or equivalent.6.3.4 Tweezers.6.4 Procedure D:6.4.1 Measuring Cup, 1.5 L.6.4.2 Tweezers.6.4.3 Hot Plate, or equivalent heating device.6.4.4 Light Fixture, equipped with GE F40/BLB, orequivalent
22、, black light bulbs.6.4.5 Ultraviolet Shield Glasses.7. Materials7.1 Detergent.7.2 Rit Tint and Dye (Navy Blue #30), or equivalent,required for Procedure C.7.3 Rit Brightener and Whitener, or equivalent, required forProcedure D.8. Hazards8.1 The ultraviolet light used in Procedures A and D isharmful
23、 to exposed skin and unprotected eyes, so a UV filteringface shield or UV absorbing glasses shall be worn whenperforming this test. Exposed hands and arms shall be coveredwith gloves and long sleeves.8.2 Hot trays and flake samples shall be handled withthermally insulated gloves to avoid burns while
24、 placing trayscontaining samples into or removing them from the oven(Procedure B).8.3 Acetone used to prepare the dye solution for ProcedureC is flammable. Use this reagent only in a well ventilated areafree of open flames or spark sources.9. Procedure9.1 Flame Test to Verify PVC Identification (Bei
25、lstein Test):9.1.1 Heat a copper wire in a propane torch flame until it isvery hot.9.1.2 Touch the hot wire to a suspected PVC flake to melt asmall amount of the flake on to the wire.9.1.3 Reheat the wire tip in the flame. If the tested flake isPVC, a bright green flame will be visible as the wire h
26、eats andthe plastic burns. Absence of a green flame indicates that thetest flake is not PVC.9.1.4 The flame test can give false positive PVC results ifthere is another halogenated material present in the PET.Brominated or chlorinated flame retardants or any additivewith a halogen will give a positiv
27、e color change with the flametest as indicated.NOTE 5CPVC, PVDC, brominated polystyrene, etc. are examples ofmaterials that will give a false positive.9.2 Procedure A:9.2.1 Weigh 454 6 10 g of clean, dry PET flake sample andtransfer the sample into a shallow aluminum tray.9.2.2 Place the tray under
28、the UV light in a dark environ-ment.9.2.3 Using tweezers, sort through the flakes in the tray andremove all particles that do not exhibit the standard PET blueor violet-blue color. Set the isolated flakes aside in a separatetray for subsequent weighing or testing in accordance with 9.1.NOTE 6Finding
29、 uniquely colored flakes under UV light should not beinterpreted as fact that these particles are PVC. PVC can exhibit manycolors (yellow/green, bright blue, dark violet, light orange) under UVlight, and because of the blue colors exhibited by some PVC material,these flakes may not be discernible fr
30、om PET flakes under UV light.NOTE 7Clear PET fluoresces strongly emitting a blue to violet-bluecolor. Other PET products, however, have been observed to fluoresce withpale blue or clear, dark purple, or turquoise colors. Green PET used forsoft drink containers normally fluoresces from a bright to a
31、dull greenunder UV light and amber PET flakes appear black under UV light.NOTE 8Paper, labels, and assorted pigmented plastics may alsoexhibit a spectrum of fluorescent colors or these materials may appearvery dark under UV light.9.3 Procedure B:9.3.1 Weigh 454 6 10 g of clean, dry PET flake sample
32、andtransfer the sample into a baking tray.9.3.2 Adjust and equilibrate the oven temperature to 235 65C.9.3.3 Quickly place the tray containing the flake into theheated oven.9.3.4 After a minimum of 45 min, remove the hot tray fromthe oven and place it on a suitable surface to cool to roomtemperature
33、.NOTE 9If heating times are short, any PVC may not char completelyand the discoloration may stop at a yellow-orange state that is typical ofD5991 172the color produced by similar heating of glue residues. The heating timemust be sufficient to totally blacken any PVC flakes. Flakes in the centerof a
34、mound of PET flakes may degrade at a slower rate than material onthe surface.9.3.5 Spread the cool, baked flake on a clean, white surface.Using tweezers, sort through the flakes in the tray and removeany black, burnt pieces of plastic.NOTE 10Burnt, melted polyethylene or PET with blackened glueresid
35、ues usually have a different physical appearance than PVC. Thesuspected presence of these contaminants will usually require testing by9.1 to verify the presence of PVC.NOTE 11While placing wet flake into the high temperature oven ispossible, the moisture will tend to keep the flake cooler for a long
36、er periodof time. Consequently, heating times longer than 45 min may be neededto compensate for this cooling effect.9.4 Procedure C:9.4.1 Transfer clean PET flake from 9.12 intoa3to4Lmetal container by tapping the flake-filled strainer against therim of the container.NOTE 12Since it is a good practi
37、ce to run a standard with any test, adda 1.54 cm square piece of known PVC to the unknown flakes.9.4.2 Add 1.2 L of the blue acetone dye solution (10 % w/v)to the container to ensure coverage of all of the flakes with thesolution. Cover the container tightly with plastic stretch wrap.9.4.3 Soak the
38、flake for 15 to 20 min, then pour the blueflake and dye solution through a strainer. Transfer the acetone/water dye solution into an appropriate glass storage vessel andseal tightly.NOTE 13If the test square of PVC (Note 10) does not stain a very darkblue, the blue dye solution may no longer be usab
39、le and it should bereplaced. As acetone evaporates from an uncovered container or lossduring transfer of the flake to the strainer, longer time will be required tocarry out this test.NOTE 14The blue acetone/water dye solution should be reused asmany times as possible. Add small amounts of 50:50 acet
40、one:water toreplenish lost liquid.9.4.4 Immediately rinse the dyed flake under running tapwater until there does not appear to be any blue liquid beingrinsed from the flakes.9.4.5 Spread the washed flake on white paper towels or aclean, white surface. Using tweezers, sort through the flakes inthe tr
41、ay and remove any uniformly dark blue stained pieces ofplastic.9.4.6 Air dry the isolated blue PVC flakes.9.5 Procedure D:9.5.1 Transfer clean PET flake intoa3to4Lmetalcontainer by tapping the flake-filled strainer against the rim ofthe container.NOTE 15Since it is a good practice to run a standard
42、with any test, adda 1.54 cm square piece of known PVC to the unknown flakes.9.5.2 Add 1500 6 10 mL of water and 3.5 6 0.2 g of the RitBrightener and Whitener to the container. Bring the mixture toa boil on a hotplate.9.5.3 After boiling for a minimum of 30 min, skim off anypaper floating on the surf
43、ace. Then remove the container fromthe hotplate and pour the contents through a strainer.9.5.4 Rinse all remaining flakes into the strainer usingadditional tap water.9.5.5 Immediately rinse the dyed flake under running tapwater to cool it down and rinse off any remaining opticalbrightener solution.9
44、.5.6 Transfer the flake from the strainer to a shallowaluminum pan making sure not to lose any of the flakes. Placethe tray under the UV light in a dark environment.9.5.7 Using tweezers, sort through the flakes in the tray andremove all particles that glow bright blue. Set the isolatedflakes aside i
45、n a separate tray for subsequent weighing ortesting in accordance with 9.1.NOTE 16Pieces of label and PET with adhering glue residues will alsoglow blue, although PET with glue residue will not show the intense bluefluorescence observed for PVC. Flimsy pieces of label are quicklyidentified from the
46、rigid PVC flake.10. Report10.1 Report the test procedure used to isolate and identifyPVC flakes.11. Keywords11.1 contamination; poly(ethylene terephthalate) (PET);poly(vinyl chloride) (PVC); recycled plasticsSUMMARY OF CHANGESCommittee D20 has identified the location of selected changes to this stan
47、dard since the last issue (D5991 - 15)that may impact the use of this standard. (December 1, 2017)(1) Section 2: Removed D7209 reference.(2) Subsection 3.1: Reworded/removed D7209 reference.(3) Section 5: Reworded; corrected spelling.(4) Added new 9.1.4 on false positive.(5) Added new Note 5.(6) Ren
48、umbered Notes615to716.D5991 173ASTM International takes 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 i
49、nfringement 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 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 receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a
