ASTM D7486-22

Standard Test Method for Measurement of Fines and Dust Particles on Plastic Pellets by Wet Analysis

SIGNIFICANCE AND USE
5.1 Molding and extruding plastic pellets require dust free, dry pellets to prevent processing problems. Plastic producers try to remove the dust and streamers with dust removal systems prior to packaging and loading. How to accurately measure dust and streamer content in plastic pellets is an important quality control issue.  
5.2 Particle size analysis is used to determine a percentage of particle size distribution from a representative sample of the whole. In terms of size analysis concerning plastic pellets, sieving is used to determine the dust content in the range of 500 to 2000 micron. Test Method D1921, Test Method B, is used to determine this type of particle sizing.  
5.3 After dry sieve analysis, particles smaller than 500 microns need to be analyzed by wet method. A fresh sample shall be used for wet analysis. This test method allows washing down the fines attached to the pellets by electrostatic forces.  
5.4 The wet analysis provides accurate quantification of small to large amounts of fines, negating static effects, and eliminating detrimental effects of mechanical agitation. A wet analysis must be employed to accurately quantify lower PPM dust levels in plastic pellets.
SCOPE
1.1 This test method measures the amount of fine particles adhered on plastic pellets or granules in which they are commonly produced and supplied. The lower limit of this test method is restricted only by the porosity of the filter disc used to capture the particle size being quantified.  
1.2 The wet analysis technique allows for separation and collection of statically charged particles by liquid wash and filtration methods. This must be performed under standard laboratory conditions.  
1.3 The values stated in SI units are to be regarded as standard.  
1.4 This test method describes an essential practice to check the quality of plastics once the production cycle is terminated and to evaluate the performance of pellet cleaning systems or of the special pneumatic conveying systems for the distinct size fractions below 500 micron only.  
1.5 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 1: There is no known ISO equivalent to this standard.  
1.6 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.

General Information

• Status: Published
• Publication Date: 31-Oct-2022
• ICS: 83.140.99 - Other rubber and plastics products
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.70 - Analytical Methods

Standards Content (Sample)

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.
Designation: D7486 − 22
Standard Test Method for
Measurement of Fines and Dust Particles on Plastic Pellets
1
by Wet Analysis
This standard is issued under the fixed designation D7486; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* D1921Test Methods for Particle Size (Sieve Analysis) of
Plastic Materials
1.1 This test method measures the amount of fine particles
E11Specification forWovenWireTest Sieve Cloth andTest
adhered on plastic pellets or granules in which they are
Sieves
commonly produced and supplied. The lower limit of this test
E691Practice for Conducting an Interlaboratory Study to
method is restricted only by the porosity of the filter disc used
Determine the Precision of a Test Method
to capture the particle size being quantified.
3
2.2 FEM Standards:
1.2 The wet analysis technique allows for separation and
FEM2482Test Method to Determine Content of Fines and
collection of statically charged particles by liquid wash and
Streamers in Plastic Pellets.
filtration methods. This must be performed under standard
laboratory conditions.
3. Terminology
1.3 The values stated in SI units are to be regarded as
3.1 Definitions—For definitions of terms associated with
standard.
plastic materials, see Terminology D883.
1.4 Thistestmethoddescribesanessentialpracticetocheck
3.2 Definitions of Terms Specific to This Standard:
the quality of plastics once the production cycle is terminated
3.2.1 fines—fines (Dust) are small particles of plastic which
and to evaluate the performance of pellet cleaning systems or
have been torn away from the original pellet by contact with a
ofthespecialpneumaticconveyingsystemsforthedistinctsize
rough surface and friction at high conveying velocities. They
fractions below 500 micron only.
are defined as the particle fraction with a particle size up to
1.5 This standard does not purport to address all of the
2000 µm.
safety concerns, if any, associated with its use. It is the
3.2.2 streamers—strings of plastics of various lengths that
responsibility of the user of this standard to establish appro-
are created when the resin travels through pneumatic convey-
priate safety, health, and environmental practices and deter-
ing lines at high velocity. Streamers are also known as angel
mine the applicability of regulatory limitations prior to use.
hair, foil, floss, film or snake skin.
NOTE 1—There is no known ISO equivalent to this standard.
4. Summary of Test Method
1.6 This international standard was developed in accor-
dance with internationally recognized principles on standard-
4.1 Fines or streamers, or both, are generated in polymer
ization established in the Decision on Principles for the
resins during pneumatic conveying. Fines and streamers are
Development of International Standards, Guides and Recom-
known to cause problems in plastic producing and processing
mendations issued by the World Trade Organization Technical
plants by clogging the transporting and procession lines. On
Barriers to Trade (TBT) Committee.
finished products, fines cause the formation of gel,
contamination, surface imperfection and weak spots.
2. Referenced Documents
2 4.2 The streamer content for a particle size considerably
2.1 ASTM Standards:
largerthanthepelletdiameteraredeterminedbydryscreening
D883Terminology Relating to Plastics
according to Test Method D1921.
1
ThistestmethodisunderthejurisdictionofASTMCommitteeD20onPlastics
4.3 The fundamental principle used in this document is
and is the direct responsibility of Subcommittee D20.70 on Analytical Methods.
based upon the condition that statically charged fines normally
Current edition approved Nov. 1, 2022. Published November 2022. Originally
adhering to plastic pellets be removed by rinsing the test
approved in 2008. Last previous edition approved in 2014 as D7486 - 14.
DOI:10.1520/D7486-22.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM AvailablefromEuropeanFederationofMaterialsHandling,DiamantBuilding,
Standards volume information, refer to the standard’s Document Summary page on 80BoulevardAugusteReyersB,1030Brussels,Belgium,http://www.fem-eur.com.
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
1

---------------------- Page: 1 -------
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
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: D7486 − 14 D7486 − 22
Standard Test Method for
Measurement of Fines and Dust Particles on Plastic Pellets
1
by Wet Analysis
This standard is issued under the fixed designation D7486; 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 test method measures the amount of fine particles adhered on plastic pellets or granules in which they are commonly
produced and supplied. The lower limit of this test method is restricted only by the porosity of the filter disc used to capture the
particle size being quantified.
1.2 The wet analysis technique allows for separation and collection of statically charged particles by liquid wash and filtration
methods. This must be performed under standard laboratory conditions.
1.3 The values stated in SI units are to be regarded as standard.
1.4 This test method describes an essential practice to check the quality of plastics once the production cycle is terminated and
to evaluate the performance of pellet cleaning systems or of the special pneumatic conveying systems for the distinct size fractions
below 500 micron only.
1.5 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
NOTE 1—There is no known ISO equivalent to this standard.
1.6 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
2.1 ASTM Standards:
D883 Terminology Relating to Plastics
D1921 Test Methods for Particle Size (Sieve Analysis) of Plastic Materials
E11 Specification for Woven Wire Test Sieve Cloth and Test Sieves
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
1
This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.70 on Analytical Methods.
Current edition approved Aug. 1, 2014Nov. 1, 2022. Published September 2014November 2022. Originally approved in 2008. Last previous edition approved in 20132014
ϵ1
as D7486 - 08(2013)14. . DOI:10.1520/D7486-14. DOI:10.1520/D7486-22.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. 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
1

---------------------- Page: 1 ----------------------
D7486 − 22
TABLE 1 Comparison of Typical Particle Sizes Measured
Type Lower Limit Upper Limit Test Method
D1921 500 μm 2000 μm dry
A
D7486 1.6 μm 500 μm wet
A
The lower limit is set by the porosity of the filter disk.
3
2.2 FEM Standards:
FEM 2482 Test Method to Determine Content of Fines and Streamers in Plastic Pellets.
3. Terminology
3.1 Definitions—For definitions of terms associated with plastic materials, see Terminology D883.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 fines—fines (Dust) are small particles of plastic which have been torn away from the original pellet by contact with a rough
surface and friction at high conveying velocities. They are defined as the particle fraction with a particle size up to 2000 μm.
3.2.2 streamers—strings of plastics of various lengths that are created when the resin travels through pneumatic conveying lines
at high velocity. Streamers are also known as angel hair, foil, floss, film or snake skin.
4. Summary of Test Method
4.1 Fines or streamers, or both, are generated in polymer resins during pneumatic conveying. Fines and streamers are known to
cause problems in plastic producing and processing plants by clogging the transporting and procession lines. On finished products,
fines cause the formation of gel, contamination, surface imperfection and
...