1、Designation: D 5991 96 (Reapproved 2002)Standard Practice forSeparation and Identification of Poly(Vinyl Chloride) (PVC)Contamination in Poly(Ethylene Terephthalate) (PET) Flake1This standard is issued under the fixed designation D 5991; the number immediately following the designation indicates the
2、 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers four procedures for separatio
3、n andqualitative identification 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 ass
4、umes the responsibility 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 u
5、ltraviolet (UV)light.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 r
6、esult in false positive 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 and health practices and determine the appli
7、ca-bility of regulatory limitations prior to use. For specific hazardssee Section 8.NOTE 3There is no equivalent ISO standard.2. Referenced Documents2.1 ASTM Standards:D 1600 Terminology for Abbreviated Terms Relating toPlastics2D 5033 Guide for the Development of Standards Relating tothe Proper Use
8、 of Recycled Plastics2E 380 Practice for Use of the International System of Units(SI) (the Modernized Metric System)33. Terminology3.1 The terminology used in this practice is in accordancewith Terminology D 1600 and Guide D 5033. Units andsymbols are in accordance with Practice E 380.3.2 Definition
9、s of Terms Specific to This Standard:3.2.1 light material, 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 p
10、roduce acharacteristic green flame.4.2 With Procedure A, 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
11、 heated on a copper wire.4.3 With Procedure B, PET flakes are heated in an ovenmaintained at 235 6 5C. After 45 min, the flakes are visuallyexamined with removal and subsequent weighing of black,charred pieces. Pieces are confirmed as PVC using the sameflame test mentioned in 4.1.4.4 With Procedure
12、C, PET flakes are soaked in a blueacetone dye solution that preferentially stains any PVC flakes.These flakes are visually identified and subsequently removed,and weighed. If desired, the identification of PVC flakes isconfirmed with the flame test.4.5 With Procedure D, PET flakes are heated with an
13、aqueous 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 fluorescing PVC flakes.5. Significance and Use5.1 Presence of even low concentrations of PVC in recycled
14、PET flakes may result in equipment corrosion problems duringprocessing. The level of PVC contamination may also dictate1This practice is under the jurisdiction of ASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.95 on Recycled Plastics.Current edition approved July
15、10, 1996. Published September 1996.2Annual Book of ASTM Standards, Vol 08.03.3Annual Book of ASTM Standards, Vol 14.02.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the market for use of the recycled polymer in secondaryproducts. P
16、rocedures presented in this practice are used toidentify and, if desired, estimate the concentration of PVCcontamination in recycled PET flakes.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, or equiva-lent, black light b
17、ulbs.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,14by20by3cm.6.2.3 Tweezers.6.2.4 Thermally Insulated Gloves, or equivalent.6.3 Procedure C:6.3.1 Measur
18、ing 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, or equiva-lent, black light bulbs.6.4.
19、5 Ultraviolet Shield Glasses.7. Materials7.1 Detergent.7.2 Rity Tint and Dye (Navy Blue #30),4or equivalent,required for Procedure C.7.3 Rity Brightener and Whitener,4or equivalent, requiredfor Procedure D.8. Hazards8.1 The ultraviolet light used in Procedures A and D may beharmful to exposed skin a
20、nd unprotected eyes, so a UV filteringface shield or UV absorbing glasses should be worn whenperforming this test. Exposed hands and arms should becovered with gloves and long sleeves.8.2 Hot trays and flake samples should be handled withthermally insulated gloves to avoid burns while placing traysc
21、ontaining 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 (Beilstein Test):9.
22、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 heats andthe pla
23、stic burns. Absence of a green flame indicates that thetest flake is not PVC.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 the UV light in a dark environ-ment.9.2.3 Using tweezers, sort through the
24、 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 4Finding uniquely colored flakes under UV light should not beinterpreted as fact t
25、hat 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 from PET flakes under UV light.NOTE 5Clear PET fluoresces strongly emitting
26、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 dull greenunder UV light and amber PET flakes appear black under UV light.
27、NOTE 6Paper, 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 andtransfer the sample into a baking tray.9.3.2 Adjust and equilibrate the
28、 oven temperature to 235 65C.9.3.3 Quickly place the tray containing the flake into theheated oven.9.3.4 After 45 min, remove the hot tray from the oven andplace it on a suitable surface to cool to room temperature.NOTE 7If heating times are short, any PVC may not char completelyand the discoloratio
29、n may stop at a yellow-orange state that is typical ofthe color produced by similar heating of glue residues. The heating timemust be sufficient to totally blacken any PVC flakes. Flakes in the centerof a mound of PET flakes may degrade at a slower rate than material onthe surface.9.3.5 Spread the c
30、ool, baked flake on a clean, white surface.Using tweezers, sort through the flakes in the tray and removeany black, burnt pieces of plastic.NOTE 8Burnt, melted polyethylene or PET with blackened glueresidues usually have a different physical appearance than PVC. Thesuspected presence of these contam
31、inants will usually require testing by9.1 to verify the presence of PVC.NOTE 9While placing wet flake into the high temperature oven ispossible, the moisture will tend to keep the flake cooler for a longer periodof time. Consequently, heating times longer than 45 min may be neededto compensate for t
32、his 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 10Since it is a good practice to run a standard with any test, add4Available from CPC Specialty Products, Indianapolis, IN.D
33、 5991 96 (2002)2a 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 flake for 15 to 20 min,
34、 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 11If the test square of PVC (Note 8) does not stain a very darkblue, the blue dye solution may no longer be usable and it should berepla
35、ced. 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 12The blue acetone/water dye solution should be reused asmany times as possible. Add small amounts of 50:50 acetone:water toreplenish lo
36、st liquid.9.4.4 Immediately rinse the dyed flake under running wateruntil there does not appear to be any blue liquid being rinsedfrom the flakes.9.4.5 Spread the washed flake on white paper towels or aclean, white surface. Using tweezers, sort through the flakes inthe tray and remove any uniformly
37、dark blue stained pieces ofplastic.9.4.6 Allow the isolated blue PVC flakes to air dry.9.5 Procedure D:9.5.1 Transfer clean PET flake intoa3to4Lmetalcontainer by tapping the flake-filled strainer against the rim ofthe container.NOTE 13Since it is a good practice to run a standard with any test, adda
38、 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 30 min, remove the container fromthe hotplate and pour the contents through a
39、strainer. Rinse allremaining flakes into the strainer using additional water.NOTE 14Additional paper floating on the surface may also beskimmed off at this time.9.5.4 Immediately rinse the dyed flake under running waterto cool it down and rinse off any remaining optical brightenersolution.9.5.5 Tran
40、sfer 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.9.5.6 Using tweezers, sort through the flakes in the tray andremove all particles that glow bright blue. Set the isolatedflakes aside in a separ
41、ate tray for subsequent weighing ortesting in accordance with 9.1.NOTE 15Pieces of label and PET with adhering glue residues willalso glow blue, although PET with glue residue will not show the intenseblue fluorescence observed for PVC. Flimsy pieces of label are quicklyidentified from the rigid PVC
42、 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 plasticsASTM International takes no position respecting the validity of any patent rights asserted in connect
43、ion 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 time by the responsibl
44、e 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 cons
45、ideration 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 International, 100 B
46、arr 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).D 5991 96 (2002)3
