1、Designation: D 5814 02Standard Practice forDetermination of Contamination in Recycled Poly(EthyleneTerephthalate) (PET) Flakes and Chips Using a Plaque Test1This standard is issued under the fixed designation D 5814; the number immediately following the designation indicates the year oforiginal adop
2、tion 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 an indication of the quality ofrecycled transparen
3、t poly(ethylene terephthalate) by examina-tion of a wafer or plaque formed by melting a representativesample and quenching it to prevent crystallization.1.2 Specific contaminants and impurities such as aluminumparticles, dirt particles, paper, and fibers are identified in thetransparent wafer.1.3 Th
4、e overall color of the plaque is indicative of oxidiz-able contaminants such as ethylene-vinyl acetate (EVA) glueresidue and the number of bubbles present in the plaque givesan indication of the moisture content of the sample.1.4 This standard does not purport to address all of thesafety concerns, i
5、f 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. Specific precau-tionary statements are given in Section 8.NOTE 1There is no equivalent I
6、SO standard.2. Referenced Documents2.1 ASTM Standards:D 1600 Terminology for Abbreviated Terms Relating toPlastics2D 5033 Guide for Development of ASTM Standards Relat-ing to Recycling and Use of Recycled Plastics2IEEE/ASTM SI 10 Standard for Use of the InternationalSystem of Units (SI): The Modern
7、Metric System33. Terminology3.1 Definitions: The terminology used in this practice is inaccordance with Terminology D 1600 and Guide D 5033. Unitsand symbols are in accordance with IEEE/ASTM SI 10:Standard for Use of the International System of Units (SI).3.2 Definitions of Terms Specific to This St
8、andard:3.2.1 plaquea transparent wafer resulting from meltingand rapid quenching of the polymer.4. Summary of Test Method4.1 Transparent poly(ethylene terephthalate) flakes aremelted in an aluminum pan, then the molten sample is rapidlyquenched in ice water to prevent crystallization. The resultingc
9、lear plaque is examined for color indicative of oxidizablecontaminants, bubbles indicative of moisture, and solid con-taminant particles.5. Significance and Use5.1 Presence of paper, metal, or incompatible polymercontamination in poly(ethylene terephthalate) renders the re-cycled polymer unfit for u
10、se in secondary product manufactur-ing operations. This procedure is useful for identifying differ-ent types of contamination in recycled PET flakes.6. Apparatus6.1 Oven, forced convection type capable of heatingsamples to 300C.6.2 Tongs, long arm.6.3 Stopwatch, 0.1-s accuracy.6.4 Bucket, 1 L, stain
11、less steel.6.5 Aluminum Weighing Dishes.46.6 Thermally Insulated Gloves.7. Materials7.1 Virgin Poly(ethylene terephthalate).7.2 Ice.7.3 Paper Towels.8. Hazards8.1 Always wear thermally insulated gloves when introduc-ing or removing the polymer sample from the oven.9. Procedure9.1 Preheat the oven to
12、 275 6 5C and equilibrate for 30min.NOTE 2Accuracy of both time and temperature is critical to valid1This practice is under the jurisdiction of ASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.70 on Analytical Methods.Current edition approved March 10, 2002. Publish
13、ed May 2002. Originallypublished as D 5814 95. Last previous edition D 5814 95.2Annual Book of ASTM Standards, Vol 08.03.3Available from ASTM International, 100 Barr Harbor Drive, West Consho-hocken, PA 194282959.4Aluminum weighing dishes, available from Fisher Scientific, or exact equiva-lents, hav
14、e been found suitable for this purpose.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.sample-to-sample comparisons using this test.9.2 Obtain three aluminum pans and label them “A,” “ B,”and “C.” Weigh 5.5 6 0.1 g of sample into eac
15、h of the pans.Tap each sample pan gently on a flat surface to evenly spreadthe chips.9.3 Weigh 5.5 6 0.1 g of virgin PET into another pan.9.4 Quickly open the oven door, place the pans in the centerof the oven, and close the oven door to minimize heat loss. Itis important that this step take place a
16、s quickly, efficiently, andreproducibly as possible.9.5 Start the stopwatch as soon as the oven temperaturerecovers and stabilizes at 275C. After 2 min, record the oventemperature (that should be 275C).9.6 Prepare an ice water bath by filling the 1-L bucket withcold tap water. Add ice and decant off
17、 some of the water tomaintain a 5-cm floating ice level on the surface of the water.The bucket should be about 90 % full with the ice and waterslurry. Place the bucket with the ice slurry as close to the ovenas possible.9.7 At 10.00 min on the stopwatch, quickly remove thesamples from the oven with
18、the tongs and immediatelysubmerge them into the ice bath. This rapid quenching preventscrystallization of the PET.9.8 Remove the pans from the ice bath and blot dry withpaper towels. Remove the hardened plastic disks formed in theoven (plaques) from the aluminum pans by peeling the pansfrom the plaq
19、ues. Label each plaque with the “A,” “B,” or “C”designation earlier assigned to each sample.9.9 Place the plaques on a white background. Compare thesample and virgin PET plaques with respect to color, numberand description of particles, and the number of bubbles.10. Report10.1 Report the following i
20、nformation:10.1.1 The sample plaque color,10.1.2 The number and description of particles in thesample plaques, and10.1.3 The number of bubbles in the sample plaques.11. Keywords11.1 contamination; plaque test; poly(ethylene terephtha-late); recycled plasticASTM International takes no position respec
21、ting 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 infringement of such rights, are entirely their own responsibility.This sta
22、ndard 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 Internati
23、onal 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 fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below
24、.This standard is copyrighted by ASTM International, 100 Barr 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 58142
