ASTM D5577-94(2003)
(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
SIGNIFICANCE AND USE
Recycled plastic materials may contain incompatible plastic or other undesirable contaminants that could affect the processing or quality, or both, of the plastic prepared for reuse. Techniques to separate and identify incompatible plastics, moisture, chemicals, or original product residues, and solid contaminants such as metals, paper, glass, and wood are essential to the processing of recycled plastic materials.
This guide lists existing ASTM and ISO methods plus currently practiced industrial techniques for identification and classification of contaminants in recycled plastics flake or pellets.
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. 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
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D5577 – 94 (Reapproved 2003)
Standard Guide for
Techniques to Separate and Identify Contaminants in
Recycled Plastics
This standard is issued under the fixed designation D5577; 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 D1003 Test Method for Haze and Luminous Transmittance
of Transparent Plastics
1.1 This guide is intended to provide information on avail-
D1193 Specification for Reagent Water
able methods for the separation and classification of contami-
D1238 Test Method for Melt Flow Rates of Thermoplastics
nants such as moisture, incompatible polymers, metals, adhe-
by Extrusion Plastometer
sives, glass, paper, wood, chemicals, and original-product
D1457 Specification for Polytetrafluoroethylene (PTFE)
residues in recycled plastic flakes or pellets. Although no
Molding and Extrusion Materials
specific methods for identification or characterization of foam
D1505 Test Method for Density of Plastics by the Density-
products are included, foam products are not excluded from
Gradient Technique
this guide. The methods presented apply to post-consumer
D1898 Practice for Sampling of Plastics
plastics.
D1925 NO TITLE
1.2 For specific procedures existing asASTM test methods,
D3418 Test Method for Transition Temperatures and En-
this guide only lists the appropriate reference. Where no
thalpies of Fusion and Crystallization of Polymers by
current ASTM standard exists, however, this guide gives
Differential Scanning Calorimetry
procedures for the separation or identification, or both, of
D4019 TestMethodforMoistureinPlasticsbyCoulometric
specific contaminants. Appendix X1 lists the tests and the
Regeneration of Phosphorus Pentoxide
specific contaminant addressed by each procedure.
D5033 Guide for Development of ASTM Standards Relat-
1.3 This guide does not include procedures to quantify the
ing to Recycling and Use of Recycled Plastics
contaminants unless this information is available in referenced
D5227 Test Method for Measurement of Hexane Extract-
ASTM standards.
able Content of Polyolefins
1.4 This standard does not purport to address all of the
E169 Practices for General Techniques of Ultraviolet-
safety concerns, if any, associated with its use. It is the
Visible Quantitative Analysis
responsibility of the user of this standard to establish appro-
E355 Practice for Gas Chromatography Terms and Rela-
priate safety and health practices and determine the applica-
tionships
bility of regulatory limitations prior to use.
E682 Practice for Liquid Chromatography Terms and Rela-
NOTE 1—Although this guide references ISO standards, there is no
tionships
similar or equivalent ISO standard covering this topic.
E794 Test Method for Melting And Crystallization Tem-
peratures By Thermal Analysis
2. Referenced Documents
E1252 Practice for General Techniques for Obtaining Infra-
2.1 ASTM Standards:
red Spectra for Qualitative Analysis
D789 Test Methods for Determination of Solution Viscosi-
2.2 ISO Standards:
ties of Polyamide (PA)
ISO 3451/1-1981 Plastics—Determination of Ash; Part 1:
D792 Test Methods for Density and Specific Gravity (Rela-
General Methods
tive Density) of Plastics by Displacement
ISO 1183-1987 Methods for Determining the Density and
D883 Terminology Relating to Plastics
Relative Density of Noncellular Plastics
3. Terminology
This guide is under the jurisdiction of ASTM Committee D20 on Plastics and
3.1 This terminology used in this guide is in accordance
is the direct responsibility of Subcommittee D20.95 on Recycled Plastics.
Current edition approved January 10, 2003. Published March 2003. Originally
with Terminology D883 and Guide D5033.
approved in 1994. Last previous edition approved in 1994 as D5577 - 94. DOI:
10.1520/D5577-94R03.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Withdrawn. The last approved version of this historical standard is referenced
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM on www.astm.org.
Standards volume information, refer to the standard’s Document Summary page on Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D5577 – 94 (2003)
3.2 Definitions of Terms Specific to This Standard: dure (13.6.1 of Specification D1457) can be used to estimate
3.2.1 chemicals—nonhazardous or hazardous materials (for the moisture content of recycled plastic materials.
example, insecticides or herbicides) potentially used in contact 7.2 Visual Inspection and Product Uniformity:
with plastic materials. 7.2.1 Color:
3.2.2 glue—adhesives used for labels or joining bottle parts 7.2.1.1 Test Method D1925 measures the yellowness index
(for example, ethylene-vinyl acetate). of clear acrylic plastics and the haze and the luminous
3.2.3 heavy metals—metals heavier than sodium on the transmittance procedure (Test Method D1003) characterizes
periodic table (for example, lead, arsenic, cadmium, chro- the color of transparent unpigmented recycled plastic materi-
mium, or copper). als. These tests are not readily applied to pigmented plastic
3.2.4 heavy plastic—unfilled polymers such as polystyrene, samples.
poly(ethylene terephthalate), and poly(vinyl chloride) and
NOTE 2—Test Method D1925 is currently being revised by ASTM
filled materials with densities greater than 1.00 g/cm .
Subcommittee D20.40 to address reproducibility and bias problems.
3.2.5 light plastic—polymers such as polyethylene and
7.2.2 Melt Flow for Product Uniformity—Uniformity of
polypropylene with densities less than 1.00 g/cm .
some recycled plastic flakes or pellets can be estimated by
3.2.6 original-product residues—residues from any
measuring the flow rate of the material using an extrusion
original-product contents of a plastic package (for example,
plastometer (Test Method D1238).
milk, juice, or detergent).
7.3 Density or Specific Gravity—The displacement method
3.2.7 particles—piece of metal, glass, wood, paper, or other
for specific gravity or relative density (Test Method D792)or
discreetly shaped material equal to or larger than 0.1 mm .
the density-gradient procedure for density (Test Method
3.2.8 specks—any material equal to or less than 0.1 mm .
D1505) are useful techniques to determine contamination of
recycledplasticflakesorpelletsampleswithoneormoreother
4. Summary of Guide
polymers.
4.1 Thisguideprovidesdetailsofseveralproceduresusedto
separate and classify contaminants including, but not limited NOTE 3—Test Method D1505 uses relatively small test specimens, so it
may not be applicable for analysis of nonhomogeneous recycled plastic
to, moisture, original product residues, incompatible plastic,
materials.
metal, paper, glass, adhesives, and wood in recycled plastic
flakes or pellets. This guide lists existing ASTM and ISO
7.4 Inorganic Contaminants:
methods that can be used to characterize solid and some liquid
7.4.1 An ash test, such as ISO 3451/1, or the muffle-furnace
contaminants. In addition, this guide presents details of some
techniques currently being evaluated within ASTM Subcom-
industry procedures for identification of contaminants.Appen-
mittee D20.70 (project designation X70-8702) can be used to
dixX1providesinformationonquantitativeaspectsofsomeof
estimate the inorganic filler content of recycled plastic flake or
these industry standards that can also be used to estimate the
pellets.
concentration of various contaminants.
NOTE 4—Some volatile metals may be lost using the test indicated in
7.4.1.ASTM Subcommittee D20.70 is currently developing a test method
5. Significance and Use
(project X70-9201) for metals, including heavy metals, that will include
5.1 Recycled plastic materials may contain incompatible sample-preparation techniques to minimize the loss of volatile metals
prior to analysis by X-ray fluorescence or spectroscopic techniques.
plastic or other undesirable contaminants that could affect the
processing or quality, or both, of the plastic prepared for reuse.
7.4.2 Ferrous (iron) contaminants can be removed with a
Techniques to separate and identify incompatible plastics,
magnet and aluminum contaminants are separated from plastic
moisture, chemicals, or original product residues, and solid
materials using density procedures in accordance with 8.3.
contaminants such as metals, paper, glass, and wood are
7.5 Thermal Analysis:
essential to the processing of recycled plastic materials.
7.5.1 Since most polymers exhibit unique temperatures for
5.2 This guide lists existing ASTM and ISO methods plus
melting or other phase transitions, measurement of these
currently practiced industrial techniques for identification and
transition temperatures (Test Method D3418) or the melting
classification of contaminants in recycled plastics flake or
and crystallization temperatures (Test Method E794)ofa
pellets.
sample may provide useful information regarding the identity
ofpolymericcomponentspresentinarecycledplasticmaterial.
6. Sampling
7.5.2 Both Test Methods D3418 and E794 involve thermal
6.1 Unless otherwise stated, materials should be sampled in
gravimetric analysis (TGA) or differential scanning calorim-
accordance with the procedures described in Practice D1898.
etry (DSC). These techniques utilize small samples (5 to 15
Adequate statistical sampling should be considered as an
mg), so they may not be practical for use in characterization of
acceptable alternative.
potentially nonhomogeneous recycled plastic materials.
7.6 Infrared Analysis—Qualitative infrared analysis using
7. Existing ASTM or ISO Procedures
the techniques of Practice E1252 can be used to identify
7.1 Moisture: polymeric, chemical, and, in some cases, inorganic compo-
7.1.1 A coulometric method (Test Method D4019), the nents of recycled plastic materials. Sample size considerations
standard test method for haze (Test Method D1003), Karl indicated in 7.5.2 may also apply to preparation of samples for
Fisher titration (Test Method D789), or a gravimetric proce- infrared analysis.
D5577 – 94 (2003)
7.7 Chromatographic Analysis—The principles of gas chro- 8.3.1.1 Fill a clean plastic container with 2 Lof clean water.
matography, described in Practice E355, and liquid chroma- Add sufficient nonionic surfactant to make a 2 % (weight/
tography, described in Practice E682, are useful for separation volume) solution and mix thoroughly.
and classification of chemical contaminants or residues from
NOTE 8—Acknowledging that water quality varies from one part of the
original-use contents of plastic packages.
countrytoanother,minimumwaterqualityforthistestincludesproperties
of Type III grade reagent water as defined in Specification D1193.
8. Additional Industrial Procedures NOTE 9—Air pockets within flake material may cause the material to
fold back on itself. The surfactant (for example, Triton X-100 ) helps
8.1 Specimen Preparation:
eliminate this problem with plastic flakes.
8.1.1 Using standard injection molding equipment, prepare
8.3.1.2 Obtain a representative sample of recycled plastic
homogenized sample plaques.
flakes (see 6.1) and weigh 100 6 10 g into a clean, dry plastic
8.1.2 Plaques, or slices from plaques prepared in 8.1.1, can
container.
be used for differential scanning calorimetry (DSC), infrared
analysis, and other test procedures requiring small, homoge- NOTE 10—The sample should be free of particles identified by a
procedure such as that described in 8.1.
neous specimens.
8.2 Visible Inspection Procedures:
8.3.1.3 Add the surfactant solution from 8.3.1.1 to the
sample container and mix well with a spatula. Allow solids to
8.2.1 Inspection Table for Large, Visible Contaminants:
settle for at least 5 min.
8.2.1.1 Using a laboratory spatula, spread 450 620gof
8.3.1.4 Skim light plastic and any contaminants (for ex-
recycled plastic flakes or pellets on a clean, white inspection
ample, paper) from the top of the water using a small kitchen
table.
strainer. Transfer these materials to a larger strainer and rinse
8.2.1.2 Without the benefit of magnification, describe the
with water to remove residual surfactant.
types of individual contaminant “particles” as defined in 3.2.7,
8.3.1.5 Pour the remaining contents from the sample con-
thenusing103magnification,describethe“specks”asdefined
tainer (see 8.3.1.4) through another large strainer and wash
in 3.2.8.
these heavier materials with water to remove residual surfac-
8.2.1.3 Thermal techniques (see 7.5) and infrared analysis
tant.
(see 7.6) can be used to identify some of the isolated contami-
8.3.1.6 If desired, these collected heavy materials are dried
nants.
and characterized by thermal (see 7.5) or infrared (see 7.6)
NOTE 5—To obtain a quantitative estimate of the contaminants, these
techniques.
contaminants can be removed and weighed, but there is not existing
8.3.2 Propanol/Water Density Separation:
precision and bias data related to this estimated contaminant concentra-
8.3.2.1 Add 1840 mL of 2-propanol and 1660 mL of water
tions in recycled plastics.
(drinking, distilled, or deionized) to a 4-L plastic bottle. Mix
8.2.2 Inspection of Molded Specimens or Plaques:
well to provide a solution containing 52 % (volume:volume)
8.2.2.1 Weigh 4 to5gofdry plastic flake on to a polyester
2-propanol in water.
sheet or aluminum foil in a 15.2 by 15.2 by 0.013-cm mold. 8.3.2.2 Pour 200 mL of the solution from 8.3.2.1 into a
Cover with another sheet of polyester film or aluminum foil, 500-mLgraduated cylinder and measure the specific gravity of
then adjust the press temperature to at least 10°C above the this solution with a hydrometer. The specific gravity should be
melting temperature of the bulk of the test material. between 0.914 and 0.917. If not, add small amounts of
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-Lplastic 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
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