ASTM D6288-23

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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: D6288 − 17 D6288 − 23
Standard Practice for
Separation and Washing of Recycled Plastics Prior to
Testing
This standard is issued under the fixed designation D6288; 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 describes a procedure for separating recycled plastics based on their color and a procedure for washing dirty,
ground plastic, which results in separation of light materials (density <1.00 g/cm ). This practice is not intended to represent
generic washing procedures used in the plastics recycling industry. The described procedures are solely for preparation of plastic
samples for use in other analytical tests. The procedure includes a room temperature wash step to facilitate separation of paper (for
example, labels) followed by washing at an elevated temperature.
NOTE 1—Although not presented as a quantitative method, the procedure presented in this practice may be used to provide quantitative results. The user
assumes the responsibility to verify the reproducibility of quantitative results.
1.2 The values stated in SI units are to be regarded as the standard.
1.3 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.
NOTE 2—There is no known ISO equivalent to this standard.
1.4 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
D3030 Test Method for Volatile Matter (Including Water) of Vinyl Chloride Resins
D5814 Practice for Determination of Contamination in Recycled Poly(Ethylene Terephthalate) (PET) Flakes and Chips Using
a Plaque Test
D5991 Practice for Separation and Identification of Poly(Vinyl Chloride) (PVC) Contamination in Poly(Ethylene Terephthalate)
(PET) Flake
E2251 Specification for Liquid-in-Glass ASTM Thermometers with Low-Hazard Precision Liquids
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 1998. Last previous edition approved in 20152017 as
D6288 - 15.D6288 - 17. DOI: 10.1520/D6288-17.10.1520/D6288-23.
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
D6288 − 23
IEEE/ASTM SI-10 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 Standard 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—material, n—materials with densities less than 1.00 g/cm .
4. Summary
4.1 Different colored plastic materials are readily distinguished by visual inspection of a sample.
4.2 Labels, glue residues and other plastics may absorb the dyes used in some procedures for identifying contaminants or these
other contaminants may exhibit interfering fluorescence. Consequently, a standard procedure is provided for washing the plastic
prior to examination by these tests.
4.3 This practice utilizes a room temperature wash step to facilitate separation of paper followed by washing at an elevated
temperature to permit separation of plastics and other contaminants based on densities. The room temperature wash step effectively
removes labels without activating some adhesives.
NOTE 3—The dye and fluorescence tests that may require plastic washed by this procedure are specifically designed to detect poly(vinyl chloride) (PVC)
contamination.
4.4 Washed recycled plastic materials are then used for tests such as those described in Practices D5814 or D5991.
5. Significance and Use
5.1 Dirt, paper and mixtures of polymeric materials complicate the interpretation of data from procedures used to identify the
contaminants in recycled plastics.
6. Apparatus
2 2
6.1 Bright Aluminum Tray, shallow depth (750 mm), with minimum area of 774 cm (120 in. ).
6.2 Balances, suitable for weighing 500 g of flake with an accuracy of 60.1 g.
6.3 Baffled Beaker, stainless steel, 15.2 cm (6 in.) diameter with four 1.9 cm (0.75 in.) baffles providing a slurry height/diameter
ratio of 0.9.
6.4 Cover for Beaker (see 6.3) which can accommodate a thermometer (or other temperature sensing device) and the stirring
impeller rod.
6.5 Overhead Stirrer, capable of 1000 r/min.
6.6 Stirring Impeller, pitched three blade, 7.62 cm (3 in.) diameter.
6.7 Plastic Pails, 19 L (5 gal).
6.8 Strainer, non-aluminum to fit the pails described in 6.7.
6.9 Hot Plate.
D6288 − 23
6.10 Thermometer, in accordance with E2251.
6.11 Manual Stirring Rod.
6.12 Oven, convection air flow capable of drying plastic flakes at 110 6 2°C.
7. Materials
7.1 Water, distilled or deionized.
7.2 Sodium Hydroxide, granular.
7.3 Detergent, nonionic surfactant.
NOTE 4—Nonylphenol or octylphenol derivatives are effective detergents for this procedure. Users of this procedure should be aware that these materials
have been linked to endocrine/estrogen activity and false positive interferences with breast cancer research. Anionic detergents may also be effective.
7.4 Wash solution, consisting of 2 L of water, 0.3 % (6 g) nonionic surfactant (see 7.3), and 1 % (20 g) sodium hydroxide (see
7.2). Dissolve the surfactant in cold water prior to addition of the sodium hydroxide.
8. Procedures
8.1 Separation of Plastics Based on Color:
8.1.1 Spread a representative portion of the recycled plastic on an aluminum tray.
NOTE 5—Use an appropriate sampling technique to insur
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