ASTM D5577-94
(Guide)Standard Guide for Techniques to Separate and Identify Contaminants in Recycled Plastics
Standard Guide for Techniques to Separate and Identify Contaminants in Recycled Plastics
SCOPE
1.1 This guide is intended to provide information on available methods for the separation and classification of contaminants such as moisture, incompatible polymers, metals, adhesives, glass, paper, wood, chemicals, and original-product residues in recycled plastic flakes or pellets. Although no specific methods for identification or characterization of foam products are included, foam products are not excluded from this guide. The methods presented apply to post-consumer plastics.
1.2 For specific procedures existing as ASTM test methods, this guide only lists the appropriate reference. Where no current ASTM standard exists, however, this guide gives procedures for the separation or identification, or both, of specific contaminants. Appendix X1 lists the tests and the specific contaminant addressed by each procedure.
1.3 This guide does not include procedures to quantify the contaminants unless this information is available in referenced ASTM standards.
1.4 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 and health practices and determine the applicability of regulatory limitations prior to use. Note 1-Although this guide references ISO standards, there is no similar or equivalent ISO standard covering this topic.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.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 5577 – 94
Standard Guide for
Techniques to Separate and Identify Contaminants in
Recycled Plastics
This standard is issued under the fixed designation D 5577; 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 D 1193 Specification for Reagent Water
D 1238 Test Method for Flow Rates of Thermoplastics by
1.1 This guide is intended to provide information on avail-
Extrusion Plastometer
able methods for the separation and classification of contami-
D 1457 Specification for Polytetrafluoroethylene (PTFE)
nants such as moisture, incompatible polymers, metals, adhe-
Molding and Extrusion Materials
sives, glass, paper, wood, chemicals, and original-product
D 1505 Test Method for Density of Plastics by the Density-
residues in recycled plastic flakes or pellets. Although no
Gradient Technique
specific methods for identification or characterization of foam
D 1898 Practice for Sampling of Plastics
products are included, foam products are not excluded from
D 1925 Test Method for Yellowness Index of Plastics
this guide. The methods presented apply to post-consumer
D 3418 Test Method for Transition Temperatures of Poly-
plastics.
mers by Thermal Analysis
1.2 For specific procedures existing as ASTM test methods,
D 4019 Test Method for Moisture in Plastics by Coulomet-
this guide only lists the appropriate reference. Where no
ric Regeneration of Phosphorus Pentoxide
current ASTM standard exists, however, this guide gives
D 5033 Guide for the Development of Standards Relating to
procedures for the separation or identification, or both, of
the Proper Use of Recycled Plastics
specific contaminants. Appendix X1 lists the tests and the
D 5227 Test Method for the Measurement of Hexane Ex-
specific contaminant addressed by each procedure.
tractable Content of Polyolefins
1.3 This guide does not include procedures to quantify the
E 169 Practices for General Techniques of Ultraviolet-
contaminants unless this information is available in referenced
Visible Quantitative Analysis
ASTM standards.
E 355 Practice for Gas Chromatography Terms and Rela-
1.4 This standard does not purport to address all of the
tionships
safety concerns, if any, associated with its use. It is the
E 682 Practice for Liquid Chromatography Terms and Re-
responsibility of the user of this standard to establish appro-
lationships
priate safety and health practices and determine the applica-
E 794 Test Method for Melting and Crystallization Tem-
bility of regulatory limitations prior to use.
peratures by Thermal Analysis
NOTE 1—Although this guide references ISO standards, there is no
E 1252 Practice for General Techniques for Qualitative
similar or equivalent ISO standard covering this topic.
Infrared Analysis
2.2 ISO Standards:
2. Referenced Documents
ISO 3451/1-1981 Plastics—Determination of Ash; Part 1:
2.1 ASTM Standards:
General Methods
D 789 Test Methods for Determination of Relative Viscos-
ISO 1183-1987 Methods for Determining the Density and
ity, Melting Point, and Moisture Content of Polyamide
Relative Density of Noncellular Plastics
(PA)
D 792 Test Methods for Specific Gravity (Relative Density)
3. Terminology
and Density of Plastics by Displacement
3.1 This terminology used in this guide is in accordance
D 883 Terminology Relating to Plastics
with Terminology D 883 and Guide D 5033.
D 1003 Test Method for Haze and Luminous Transmittance
of Transparent Plastics
Annual Book of ASTM Standards, Vol 11.01.
Annual Book of ASTM Standards, Vol 08.02.
Annual Book of ASTM Standards, Vol 08.03.
This guide is under the jurisdiction of ASTM Committee D-20 on Plastics and
Annual Book of ASTM Standards, Vol 14.01.
is the direct responsibility of Subcommittee D20.70 on Analytical Methods.
Annual Book of ASTM Standards, Vol 14.02.
Current edition approved June 15, 1994. Published August 1994.
Available from American National Standards Institute, 11 W. 42nd St., 13th
Annual Book of ASTM Standards, Vol 08.01.
Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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.
D 5577
3.2 Definitions of Terms Specific to This Standard: 7.2 Visual Inspection and Product Uniformity:
3.2.1 chemicals—nonhazardous or hazardous materials (for 7.2.1 Color:
example, insecticides or herbicides) potentially used in contact 7.2.1.1 Test Method D 1925 measures the yellowness index
with plastic materials. of clear acrylic plastics and the haze and the luminous
3.2.2 glue—adhesives used for labels or joining bottle parts transmittance procedure (Test Method D 1003) characterizes
(for example, ethylene-vinyl acetate). the color of transparent unpigmented recycled plastic materi-
3.2.3 heavy metals—metals heavier than sodium on the als. These tests are not readily applied to pigmented plastic
periodic table (for example, lead, arsenic, cadmium, chro- samples.
mium, or copper).
NOTE 2—Test Method D 1925 is currently being revised by ASTM
3.2.4 heavy plastic—unfilled polymers such as polystyrene,
Subcommittee D20.40 to address reproducibility and bias problems.
poly(ethylene terephthalate), and poly(vinyl chloride) and
7.2.2 Melt Flow for Product Uniformity—Uniformity of
filled materials with densities greater than 1.00 g/cm .
some recycled plastic flakes or pellets can be estimated by
3.2.5 light plastic—polymers such as polyethylene and
measuring the flow rate of the material using an extrusion
polypropylene with densities less than 1.00 g/cm .
plastometer (Test Method D 1238).
3.2.6 original-product residues—residues from any
7.3 Density or Specific Gravity—The displacement method
original-product contents of a plastic package (for example,
for specific gravity or relative density (Test Method D 792) or
milk, juice, or detergent).
the density-gradient procedure for density (Test Method
3.2.7 particles—piece of metal, glass, wood, paper, or other
D 1505) are useful techniques to determine contamination of
discreetly shaped material equal to or larger than 0.1 mm .
recycled plastic flakes or pellet samples with one or more other
3.2.8 specks—any material equal to or less than 0.1 mm .
polymers.
4. Summary of Guide
NOTE 3—Test Method D 1505 uses relatively small test specimens, so
4.1 This guide provides details of several procedures used to
it may not be applicable for analysis of nonhomogeneous recycled plastic
materials.
separate and classify contaminants including, but not limited
to, moisture, original product residues, incompatible plastic,
7.4 Inorganic Contaminants:
metal, paper, glass, adhesives, and wood in recycled plastic 7.4.1 An ash test, such as ISO 3451/1, or the muffle-furnace
flakes or pellets. This guide lists existing ASTM and ISO
techniques currently being evaluated within ASTM Subcom-
methods that can be used to characterize solid and some liquid mittee D20.70 (project designation X70-8702) can be used to
contaminants. In addition, this guide presents details of some
estimate the inorganic filler content of recycled plastic flake or
industry procedures for identification of contaminants. Appen-
pellets.
dix X1 provides information on quantitative aspects of some of
NOTE 4—Some volatile metals may be lost using the test indicated in
these industry standards that can also be used to estimate the
7.4.1. ASTM Subcommittee D20.70 is currently developing a test method
concentration of various contaminants.
(project X70-9201) for metals, including heavy metals, that will include
sample-preparation techniques to minimize the loss of volatile metals
5. Significance and Use
prior to analysis by X-ray fluorescence or spectroscopic techniques.
5.1 Recycled plastic materials may contain incompatible
7.4.2 Ferrous (iron) contaminants can be removed with a
plastic or other undesirable contaminants that could affect the
magnet and aluminum contaminants are separated from plastic
processing or quality, or both, of the plastic prepared for reuse.
materials using density procedures in accordance with 8.3.
Techniques to separate and identify incompatible plastics,
7.5 Thermal Analysis:
moisture, chemicals, or original product residues, and solid
7.5.1 Since most polymers exhibit unique temperatures for
contaminants such as metals, paper, glass, and wood are
melting or other phase transitions, measurement of these
essential to the processing of recycled plastic materials.
transition temperatures (Test Method D 3418) or the melting
5.2 This guide lists existing ASTM and ISO methods plus
and crystallization temperatures (Test Method E 794) of a
currently practiced industrial techniques for identification and
sample may provide useful information regarding the identity
classification of contaminants in recycled plastics flake or
of polymeric components present in a recycled plastic material.
pellets.
7.5.2 Both Test Methods D 3418 and E 794 involve thermal
6. Sampling gravimetric analysis (TGA) or differential scanning calorim-
etry (DSC). These techniques utilize small samples (5 to 15
6.1 Unless otherwise stated, materials should be sampled in
mg), so they may not be practical for use in characterization of
accordance with the procedures described in Practice D 1898.
potentially nonhomogeneous recycled plastic materials.
Adequate statistical sampling should be considered as an
7.6 Infrared Analysis—Qualitative infrared analysis using
acceptable alternative.
the techniques of Practice E 1252 can be used to identify
7. Existing ASTM or ISO Procedures
polymeric, chemical, and, in some cases, inorganic compo-
7.1 Moisture: nents of recycled plastic materials. Sample size considerations
7.1.1 A coulometric method (Test Method D 4019), the indicated in 7.5.2 may also apply to preparation of samples for
standard test method for haze (Test Method D 1003), Karl infrared analysis.
Fisher titration (Test Method D 789), or a gravimetric proce- 7.7 Chromatographic Analysis—The principles of gas chro-
dure (13.6.1 of Specification D 1457) can be used to estimate matography, described in Practice E 355, and liquid chroma-
the moisture content of recycled plastic materials. tography, described in Practice E 682, are useful for separation
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.
D 5577
of Type III grade reagent water as defined in Specification D 1193.
and classification of chemical contaminants or residues from
NOTE 9—Air pockets within flake material may cause the material to
original-use contents of plastic packages.
fold back on itself. The surfactant (for example, Triton X-100 ) helps
8. Additional Industrial Procedures eliminate this problem with plastic flakes.
8.1 Specimen Preparation:
8.3.1.2 Obtain a representative sample of recycled plastic
8.1.1 Using standard injection molding equipment, prepare flakes (see 6.1) and weigh 100 6 10 g into a clean, dry plastic
homogenized sample plaques.
container.
8.1.2 Plaques, or slices from plaques prepared in 8.1.1, can
NOTE 10—The sample should be free of particles identified by a
be used for differential scanning calorimetry (DSC), infrared
procedure such as that described in 8.1.
analysis, and other test procedures requiring small, homoge-
8.3.1.3 Add the surfactant solution from 8.3.1.1 to the
neous specimens.
sample container and mix well with a spatula. Allow solids to
8.2 Visible Inspection Procedures:
settle for at least 5 min.
8.2.1 Inspection Table for Large, Visible Contaminants:
8.3.1.4 Skim light plastic and any contaminants (for ex-
8.2.1.1 Using a laboratory spatula, spread 450 6 20gof
ample, paper) from the top of the water using a small kitchen
recycled plastic flakes or pellets on a clean, white inspection
strainer. Transfer these materials to a larger strainer and rinse
table.
with water to remove residual surfactant.
8.2.1.2 Without the benefit of magnification, describe the
8.3.1.5 Pour the remaining contents from the sample con-
types of individual contaminant “particles” as defined in 3.2.7,
tainer (see 8.3.1.4) through another large strainer and wash
then using 103 magnification, describe the “specks” as defined
these heavier materials with water to remove residual surfac-
in 3.2.8.
tant.
8.2.1.3 Thermal techniques (see 7.5) and infrared analysis
8.3.1.6 If desired, these collected heavy materials are dried
(see 7.6) can be used to identify some of the isolated contami-
and characterized by thermal (see 7.5) or infrared (see 7.6)
nants.
techniques.
NOTE 5—To obtain a quantitative estimate of the contaminants, these
8.3.2 Propanol/Water Density Separation:
contaminants can be removed and weighed, but there is not existing
8.3.2.1 Add 1840 mL of 2-propanol and 1660 mL of water
precision and bias data related to this estimated contaminant concentra-
(drinking, distilled, or deionized) to a 4-L plastic bottle. Mix
tions in recycled plastics.
well to provide a solution containing 52 % (volume:volume)
8.2.2 Inspection of Molded Specimens or Plaques:
2-propanol in water.
8.2.2.1 Weigh 4 to5gofdry plastic flake on to a polyester
8.3.2.2 Pour 200 mL of the solution from 8.3.2.1 into a
sheet or aluminum foil in a 15.2 by 15.2 by 0.013-cm mold.
500-mL graduated cylinder and measure the specific gravity of
Cover with another sheet of polyester film or aluminum foil,
this solution with a hydrometer. The specific gravity should be
then adjust the press temperature to at least 10°C above the
between 0.914 and 0.917. If not, add small amounts of
melting temperature of the bulk of the test material.
2-propanol or water to the solution from 8.3.2.1 to bring the
8.2.2.2 Press a plaque from the recycled plastic sample.
specific gravity into the desired range.
Remove the plaque from the press and cool.
8.3.2.3 Weigh 100 6 10 g dry light plastic (see 8.3.1.4) into
8.2.2.3 Visually examine the test plaque within a 10-cm
a 4-L plastic pail, then add the 52 % 2-propanol/water solution
area using a fluorescent-light table. For comparison, repeat
(see 8.3.2.1) to this container. Stir contents with a rubber
8.3.1 and 8.3.2 with a portion of virgin resin representing the
spatula to wet all flakes, then allow solids to settle.
bulk of the test material (for example, poly(ethylene tereph-
8.3.2.4 Skim any plastic from the top of thi
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