ASTM D5991-23

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it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D5991 − 17 D5991 − 23
Standard Practice for
Separation and Identification of Poly(Vinyl Chloride) (PVC)
Contamination in Poly(Ethylene Terephthalate) (PET) Flake
This standard is issued under the fixed designation D5991; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This practice covers four procedures for separation and qualitative identification of poly(vinyl chloride) (PVC) contamination
in poly(ethylene terephthalate) (PET) flakes.
NOTE 1—Although not presented as a quantitative method, procedures presented in this practice may be used to provide quantitative results at the
discretion of the user. The user assumes the responsibility to verify the reproducibility of quantitative results. Data from an independent source suggest
a PVC detection level of 200 ppm (w/w) based on an original sample weight of 454 g.
1.2 Procedure A is based on different fluorescence of PVC and PET when these polymers are exposed to ultraviolet (UV) light.
1.3 Procedure B is an oven test based upon the charring of PVC when it is heated in air at 235°C.
1.4 Procedures C and D are dye tests based on differential staining of PVC and PET.
NOTE 2—Other polymers (for example, PETG) also absorb the stain or brightener. Such interferences will result in false positive identification of PVC
as the contaminant.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use. For specific hazards see Section 8.
NOTE 3—There is no known ISO equivalent to this standard.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D883 Terminology Relating to Plastics
D1600 Terminology for Abbreviated Terms Relating to Plastics
This practice is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.95 on Recycled Plastics.
Current edition approved Dec. 1, 2017Feb. 1, 2023. Published January 2018February 2023. Originally approved in 1996. Last previous edition approved in 20152017 as
D5991 - 15.D5991 - 17. DOI: 10.1520/D5991-17.10.1520/D5991-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5991 − 23
IEEE/ASTM SI-10 American National Standard for Use of the International System of Units (SI): The Modern Metric System
3. Terminology
3.1 Definitions—The terminology used in this practice is in accordance with For definitions of terms that appear in this
specification relating to plastics, refer to Terminology D1600D883. Units and symbols are in accordance with For abbreviations
that appear in the specification, refer to Terminology IEEE/ASTM SI-10D1600.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 light material, n—paper, polymers such as polyethylene and polypropylene, and other materials with densities less than 1.00
g/cm .
4. Summary of Practice
4.1 For the Beilstein Test, chlorine-containing materials heated in a flame in contact with a copper wire produce a characteristic
green flame.
4.2 With Procedure A, a known amount of PET flakes is exposed to ultraviolet radiation. PET normally fluoresces with a blue or
violet color. Flakes fluorescing with different colors are removed, weighed, and identified as PVC if they burn with a bright green
flame when heated on a copper wire.
4.3 With Procedure B, PET flakes are heated in an oven maintained at 235 6 5°C. After a minimum of 45 min, the flakes are
visually examined with removal and subsequent weighing of black, charred pieces. Pieces are confirmed as PVC using the same
flame test mentioned in 4.1.
4.4 With Procedure C, PET flakes are soaked in a blue acetone dye solution that preferentially stains any PVC flakes. These flakes
are visually identified and subsequently removed, and weighed. The identification of PVC flakes is confirmed with the flame test.
4.5 With Procedure D, PET flakes are heated with an aqueous solution containing an optical brightener that also preferentially
stains the PVC flakes. The flakes are sorted under UV light in a dark room with removal and subsequent weighing of any blue
fluorescing PVC flakes.
5. Significance and Use
5.1 Presence of even low concentrations of PVC in recycled PET flakes results in equipment corrosion problems during
processing. The PVC contamination level shall dictate the market for use of the recycled polymer in secondary products.
Procedures presented in this practice are used to identify the PVC contamination in recycled PET flakes.
NOTE 4—These procedures may also be used to estimate the concentration of PVC contamination.
6. Apparatus
6.1 Procedure A:
6.1.1 Bright Aluminum Tray, shallow depth (0.75 cm).
6.1.2 Light Fixture, equipped with GE F40/BLB, or equivalent, 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 a temperature readout device for the range of 230 to 240°C.
D5991 − 23
6.2.2 Baking Trays, 14 by 20 by 3 cm.
6.2.3 Tweezers.
6.2.4 Thermally Insulated Gloves, or equivalent.
6.3 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, or equivalent, black light bulbs.
6.4.5 Ultraviolet Shield Glasses.
7. Materials
7.1 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 for Procedure D.
8. Hazards
8.1 The ultraviolet light used in Procedures A and D is harmful to exposed skin and unprotected eyes, so a UV filtering face shield
or UV absorbing glasses shall be worn when performing this test. Exposed hands and arms shall be covered with gloves and long
sleeves.
8.2 Hot trays and flake samples shall be handled with thermally insulated gloves to avoid burns while placing trays containing
samples into or removing them from the oven (Procedure B).
8.3 Acetone used to prepare the dye solution for Procedure C is flammable. Use this reagent only in a well ventilated area free
of open flames or spark sources.
9. Procedure
9.1 Flame Test to Verify PVC Identification (Beilstein Test):
9.1.1 Heat a copper wire in a propane torch flame until it is very hot.
9.1.2 Touch the hot wire to a suspected PVC flake to melt a small amount of the flake on to the wire.
D5991 − 23
9.1.3 Reheat the wire tip in the flame. If the tested flake is PVC, a bright green flame will be visible as the wire heats and the plastic
burns. Absence of a green flame indicates that the test flake is not PVC.
9.1.4 The flame test can give false positive PVC results if there is another halogenated material present in the PET. Brominated
or chlorinated flame retardants or any additive with a halogen will
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