ASTM D6288-98(2003)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D6288–98 (Reapproved 2003)
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 (Vinyl Chloride) (PVC) Contamination in Poly(Ethylene
Terephthalate) (PET) Flake
1.1 The practice describes a procedure for separating re-
IEEE/ASTM SI 10 Standard for Use of the International
cycled plastics based on their color (for example, green versus
System of Units (SI): The Modern Metric System
colorless) and a procedure for washing dirty, ground plastic
which results in separation of light materials (density < 1.00
3. Terminology
g/cm ). This practice is not intended to represent generic
3.1 The terminology used in this practice is in accordance
washing procedures used in the plastics recycling industry.The
with Terminology D 1600 and Guide D 5033. Units and
described procedures are solely for preparation of plastic
symbols are in accordance with Standard IEEE/ASTM SI 10.
samples for use in other analytical tests. The procedure
3.2 Definitions of Terms Specific to This Standard:
includes a room temperature wash step to facilitate separation
3.2.1 light material—paper, polymers such as polyethylene
of paper (for example, labels) followed by washing at an
and polypropylene, and other materials with densities less than
elevated temperature.
1.00 g/cm .
NOTE 1—Although not presented as a quantitative method, the proce-
dure presented in this practice may be used to provide quantitative results.
4. Summary
The user assumes the responsibility to verify the reproducibility of
4.1 Different colored (for example, green versus colorless)
quantitative results.
plastic materials are readily distinguished by visual inspection
1.2 The values stated in SI units are to be regarded as the
of a sample.
standard.
4.2 Labels, glue residues and other plastics may absorb the
1.3 This standard does not purport to address all of the
dyes used in some procedures for identifying contaminants or
safety concerns, if any, associated with its use. It is the
these other contaminants may exhibit interfering fluorescence.
responsibility of the user of this standard to establish appro-
Consequently, a standard procedure is provided for washing
priate safety and health practices and determine the applica-
the plastic prior to examination by these tests.
bility of regulatory limitations prior to use.
4.3 This practice utilizes a room temperature wash step to
facilitate separation of paper (for example, labels) followed by
NOTE 2—There is no equivalent ISO standard.
washing at an elevated temperature to permit separation of
2. Referenced Documents
plastics and other contaminants based on densities. The room
2.1 ASTM Standards: temperature wash step effectively removes labels without
activating some adhesives.
D 1600 Terminology for Abbreviated Terms Relating to
Plastics
NOTE 3—The dye and fluorescence tests that may require plastic
D 5033 GuidefortheDevelopmentofStandardsRelatingto
washed by this procedure are specifically designed to detect poly(vinyl
the Proper Use of Recycled Plastics
chloride) (PVC) contamination.
D 5814 Practice for Determination of Contamination in
4.4 Washed recycled plastic materials are then used for tests
Recycled Poly(Ethylene Terephthalate) (PET) Flakes and
such as those described in Practices D 5814 or D 5991.
Chips Using a Plaque Test
E 5991 Practice for Separation and Identification of Poly-
5. Significance and Use
5.1 Dirt, paper and mixtures of polymeric materials com-
plicate the interpretation of data from procedures used to
This practice is under the jurisdiction ofASTM Committee D20 on Plastics and
identify and, if desired, quantify the contaminants in recycled
is the direct responsibility of Subcommittee D20.95 on Recycled Plastics.
Current edition approved July 10, 2003. Published September 2003. Originally plastics.
approved in 1998. Last previous edition approved in 1998 as D 6288 - 98.
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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D6288–98 (2003)
NOTE 7—Bubbles may be attached to plastic flakes and these bubbles
6. Apparatus
maycauseheavymaterialstofloatwhentheywouldotherwisesink.Using
6.1 Bright Aluminum Tray, shallow depth (750 mm), with
a screen to gently disturb the floating particles and cause release of the air
2 2
minimum area of 774 cm [120 in. ].
may permit these heavy materials to sink instead of float.
6.2 Balances, suitable for weighing 500 g of flake.
8.2.5 After 15 min, turn off the overhead stirrer and remove
6.3 Baffled Beaker, stainless steel, 15.2 cm [6 in.] diameter
it from the baffled beaker. Wait 5 min to allow paper and other
with four 1.9 cm [0.75 in.] baffles providing a slurry height/
light materials to rise to the surface and polymers such as PET
diameter ratio of 0.9.
and PVC to sink. Using the manual stirring rod (see 6.11),
6.4 Cover for Beaker (see 6.3) which can accommodate a
gently agitate the light materials to allow any trapped PET or
thermometer (or other temperature sensing device) and the
PVC to sink.
stirring impeller rod.
8.2.6 Place a strainer (see 6.8) over a 19 L pail (see 6.7).
6.5 Overhead Stirrer, capable of 1000 r/min.
Carefully pour the wash solution from the beaker through the
6.6 Stirring Impeller, pitched three blade, 7.62 cm [3 in.]
strainercausingthelightmaterialstobetrappedonthestrainer.
diameter.
Do not allow the heavier plastic material that sett
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