ASTM D6288-98

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 6288 – 98
Standard Practice for
Separation and Washing of Recycled Plastics Prior to
Testing
This standard is issued under the fixed designation D 6288; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope E 5991 Practice for Separation and Identification of Poly-
(Vinyl Chloride) (PVC) Contamination in Poly(Ethylene
1.1 The practice describes a procedure for separating re-
Terephthalate) (PET) Flake
cycled plastics based on their color (for example, green versus
IEEE/ASTM SI 10 Standard for Use of the International
colorless) and a procedure for washing dirty, ground plastic
System of Units (SI): The Modern Metric System
which results in separation of light materials (density < 1.00
g/cm ). This practice is not intended to represent generic
3. Terminology
washing procedures used in the plastics recycling industry. The
3.1 The terminology used in this practice is in accordance
described procedures are solely for preparation of plastic
with Terminology D 1600 and Guide D 5033. Units and
samples for use in other analytical tests. The procedure
symbols are in accordance with Standard IEEE/ASTM SI 10.
includes a room temperature wash step to facilitate separation
3.2 Definitions of Terms Specific to This Standard:
of paper (for example, labels) followed by washing at an
3.2.1 light material—paper, polymers such as polyethylene
elevated temperature.
and polypropylene, and other materials with densities less than
NOTE 1—Although not presented as a quantitative method, the proce-
1.00 g/cm .
dure presented in this practice may be used to provide quantitative results.
The user assumes the responsibility to verify the reproducibility of
4. Summary
quantitative results.
4.1 Different colored (for example, green versus colorless)
1.2 The values stated in SI units are to be regarded as the
plastic materials are readily distinguished by visual inspection
standard.
of a sample.
1.3 This standard does not purport to address all of the
4.2 Labels, glue residues and other plastics may absorb the
safety concerns, if any, associated with its use. It is the
dyes used in some procedures for identifying contaminants or
responsibility of the user of this standard to establish appro-
these other contaminants may exhibit interfering fluorescence.
priate safety and health practices and determine the applica-
Consequently, a standard procedure is provided for washing
bility of regulatory limitations prior to use.
the plastic prior to examination by these tests.
4.3 This practice utilizes a room temperature wash step to
NOTE 2—There is no equivalent ISO standard.
facilitate separation of paper (for example, labels) followed by
2. Referenced Documents
washing at an elevated temperature to permit separation of
plastics and other contaminants based on densities. The room
2.1 ASTM Standards:
D 1600 Terminology for Abbreviated Terms Relating to temperature wash step effectively removes labels without
activating some adhesives.
Plastics
D 5033 Guide for the Development of Standards Relating to
NOTE 3—The dye and fluorescence tests that may require plastic
the Proper Use of Recycled Plastics
washed by this procedure are specifically designed to detect poly(vinyl
D 5814 Practice for Determination of Contamination in
chloride) (PVC) contamination.
Recycled Poly(Ethylene Terephthalate) (PET) Flakes and
4.4 Washed recycled plastic materials are then used for tests
Chips Using a Plaque Test
such as those described in Practices D 5814 or D 5991.
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 July 10, 1998. Published February 1999.
Annual Book of ASTM Standards, Vol 08.01.
3 4
Annual Book of ASTM Standards, Vol 08.03. Annual Book of ASTM Standards, Vol 14.02.
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D6288–98
5. Significance and Use 8.2.2 Select and accurately weigh 500 6 20 g of dirty
plastic from the sample. Add this sample to the solution in the
5.1 Dirt, paper and mixtures of polymeric materials com-
beaker.
plicate the interpretation of data from procedures used to
8.2.3 Insert the overhead stirrer so that the impeller is 2.54
identify and, if desired, quantify the contaminants in recycled
cm (1 in.) above the bottom of the beaker.
plastics.
8.2.4 Turn on the overhead stirrer and adjust the speed to
1000 r/min. Continue agitation for 15 min at room temperature
6. Apparatus
(25 6 2°C).
6.1 Bright Aluminum Tray, shallow depth (750 mm), with
2 2
minimum area of 774 cm (120 in. ). NOTE 7—Bubbles may be attached to plastic flakes and these bubbles
may cause heavy materials to float when they would otherwise sink. Using
6.2 Balances, suitable for weighing 500 g of flake.
a screen to gently disturb the floating particles and cause release of the air
6.3 Baffled Beaker, stainless steel, 15.2 cm (6 in.) diameter
may permit these heavy materials to sink instead of float.
with four 1.9 cm (0.75 in.) baffles providing a slurry height/
diameter ratio of 0.9.
8.2.5 After 15 min, turn off the overhead stirrer and remove
6.4 Cover for Beaker (see 6.3) which can accommodate a it from the baffled beaker. Wait 5 min to allow paper and other
thermometer (or other temperature sensing device) and the
light materials to rise to the surface and polymers such as PET
stirring impeller rod. and PVC to sink. Using the manual stirring rod (see 6.11),
6.5 Overhead Stirrer, capable of 1000 r/min.
gently agitate the light materials to allow any trapped PET or
6.
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