ASTM D1921-96

Standard Test Methods for Particle Size (Sieve Analysis) of Plastic Materials

SCOPE
1.1 These test methods cover the measurement of the particle size of plastic materials in the powdered, granular, or pelleted forms in which they are commonly supplied. As these test methods utilize dry sieving, the lower limit of measurement is considered to be about 38 microns (No. 400 sieve). For smaller particle sizes, sedimentation methods are recommended.  
1.2 Two test methods are described:  
1.2.1 Test Method A—This test method uses multiple sieves selected to span the particle size of the material. The mean particle diameter and distribution can be determined by this test method.  
1.2.2  Test Method B—This test method is an abbreviated version of Test Method A conducted with a few specific sieves. This test method determines "percent passing" or "percent retained" on a given sieve. Test Method B is applicable to materials which do not have a normal particle size distribution such as pellets and cubes.  
1.3 The values as stated in inch-pound units are to be regarded as the standard. The values given in parentheses are given for information only.  
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-—There is no technically equivalent ISO standard.

General Information

• Status: Historical
• Publication Date: 09-Aug-2001
• ICS: 19.120 - Particle size analysis. Sieving
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.70 - Analytical Methods

Relations

• Replaced By: ASTM D1921-01 - Standard Test Methods for Particle Size (Sieve Analysis) of Plastic Materials
• Effective Date: 10-Aug-2001
• Referred By: ASTM D4020-18 - Standard Specification for Ultra-High-Molecular-Weight Polyethylene Molding and Extrusion Materials
• Effective Date: 10-Aug-2001
• Referred By: ASTM D5861-07(2017) - Standard Guide for Significance of Particle Size Measurements of Coating Powders
• Effective Date: 10-Aug-2001
• Referred By: ASTM E1229-21 - Standard Specification for Calcium Hypochlorite
• Effective Date: 10-Aug-2001
• Referred By: ASTM D3451-06(2017) - Standard Guide for Testing Coating Powders and Powder Coatings
• Effective Date: 10-Aug-2001
• Referred By: ASTM D8424-21 - Standard Guide for Retroreflective Composite Optics Laboratory Procedures
• Effective Date: 10-Aug-2001
• Referred By: ASTM D8402-23 - Standard Practice for Development of Microplastic Reference Samples for Calibration and Proficiency Evaluation in All Types of Water Matrices with High to Low Levels of Suspended Solids
• Effective Date: 10-Aug-2001
• Referred By: ASTM D7486-22 - Standard Test Method for Measurement of Fines and Dust Particles on Plastic Pellets by Wet Analysis
• Effective Date: 10-Aug-2001
• Referred By: ASTM D3218-07(2018) - Standard Specification for Polyolefin Monofilaments
• Effective Date: 10-Aug-2001
• Referred By: ASTM D1755-21 - Standard Specification for Poly(Vinyl Chloride) Resins
• Effective Date: 10-Aug-2001

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 1921 – 96 An American National Standard
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Methods for
Particle Size (Sieve Analysis) of Plastic Materials
This standard is issued under the fixed designation D 1921; 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 3. Summary of Test Methods
1.1 These test methods cover the measurement of the 3.1 A dry mass of plastic material is placed on a series of
particle size of plastic materials in the powdered, granular, or sieves arranged in order of increasing fineness and the mass is
pelleted forms in which they are commonly supplied. As these divided into fractions corresponding to the sieve opening.
test methods utilize dry sieving, the lower limit of measure-
4. Significance and Use
ment is considered to be about 38 μm (No. 400 sieve). For
smaller particle sizes, sedimentation test methods are recom- 4.1 These test methods can be used to determine particle
mended. size distribution and therefore are useful for determining
lot-to-lot uniformity.
1.2 Two test methods are described:
1.2.1 Test Method A—This test method uses multiple sieves 4.2 The particle sizes of plastic materials affect the handling
characteristics and may affect the processing characteristics of
selected to span the particle size of the material. The mean
particle diameter and distribution can be determined by this test some polymers.
method.
5. Interferences
1.2.2 Test Method B—This test method is an abbreviated
5.1 Some materials develop a static charge during sieving.
version of Test Method A conducted with a few specific sieves.
This charge interferes with the sieving process and results in a
This test method determines “percent passing” or “percent
coarse bias. Use of an antistat is necessary to obtain meaning-
retained” on a given sieve. Test Method B is applicable to
ful results.
materials which do not have a normal particle size distribution
5.2 The choice of antistat (or slip agent) will affect the
such as pellets and cubes.
coarse bias. Some materials are more effective in aiding the
1.3 The values stated in inch-pound units are to be regarded
fines to separate from the mass.
as the standard. The values given in parentheses are given for
5.3 Too much material on a sieve causes mass blinding and
information only.
results in a coarse bias. The sieve selection and charge weight
1.4 This standard does not purport to address all of the
must be chosen to avoid overloading any sieve.
safety concerns, if any, associated with its use. It is the
5.4 Wavy, improperly stretched wire-cloth may allow wires
responsibility of the user of this standard to establish appro-
to separate without being visually damaged. Sieves with wavy
priate safety and health practices and determine the applica-
or torn wires should be discarded, as they no longer conform to
bility of regulatory limitations prior to use.
Specification E 11.
NOTE 1—There is no technically equivalent ISO standard.
6. Apparatus
2. Referenced Documents
6.1 Balance, 500-g minimum capacity with ⁄10-g sensitiv-
2.1 ASTM Standards:
ity.
E 11 Specification for Wire-Cloth Sieves for Testing Pur-
6.2 Mechanical Sieving Device and Time Switch—A me-
poses
chanical sieve-shaking device equipped with an automatic time
E 691 Practice for Conducting an Interlaboratory Study to
switch. This device shall be capable of imparting uniform
Determine the Precision of a Test Method
rotary motion and a tapping action at a rate of 150 6 10
taps/min.
These test methods are under the jurisdiction of ASTM Committee D-20 on
6.3 Wire Cloth Sieves, woven wire cloth conforming to
Plastics and are the direct responsibility of Subcommittee D20.70 on Analytic
Specification E 11, as shown in Table 1, mounted in 8-in.
Methods (Section D20.70.01).
Current edition approved Aug. 10, 1996. Published February 1997. Originally (203-mm) frames. The number of sieves and the choice of sizes
published as D 1921 – 61 T. Last previous edition D 1921 – 89.
shall be selected for the material being tested. A cover and a
This revision adds an ISO equivalency statement, includes Table 1 showing sieve
bottom pan are also required.
size openings, and has wording changes in Sections 10, 12, 13, and 15.
6.4 Accessories for Cleaning the Screens:
Annual Book of ASTM Standards, Vol 14.02.
D 1921
TABLE 1 Nominal Dimensions, Permissible Variations for Wire Cloth of Standard Test Sieves (U.S.A.) Standard Series
Permissible
Opening Dimension
Sieve Designation
Variation of
Nominal Sieve Exceeded By Not Maximum Nominal Wire
Average Opening
A B
Opening, in. More Than 5 % of Individual Opening Diameter, mm
from the Standard
C
Standard Alternative
the Openings
Sieve Designation
(1) (2) (3) (4) (5) (6) (7)
125 mm 5 in. 5 63.70 mm 130.0 mm 130.9 mm 8.00
106 mm 4.24 in. 4.24 63.20 mm 110.2 mm 111.1 mm 6.30
D D
100 mm 4 in. 4 63.00 mm 104.0 mm 104.8 mm 6.30
90 mm 3 ⁄2 in. 3.5 62.70 mm 93.6 mm 94.4 mm 6.30
75 mm 3 in. 3 62.20 mm 78.1 mm 78.7 mm 6.30
63 mm 2 ⁄2 in. 2.5 61.90 mm 65.6 mm 66.2 mm 5.80
53 mm 2.12 in. 2.12 61.60 mm 55.2 mm 55.7 mm 5.00
D D
50 mm 2 in. 2 61.50 mm 52.1 mm 52.6 mm 5.00
45 mm 1 ⁄4 in. 1.75 61.40 mm 46.9 mm 47.4 mm 4.50
37.5 mm 1 ⁄2 in. 1.5 61.10 mm 39.1 mm 39.5 mm 4.50
31.5 mm 1 ⁄4 in. 1.25 61.00 mm 32.9 mm 33.2 mm 4.00
26.5 mm 1.06 in. 1.06 6800 mm 27.7 mm 28.0 mm 3.55
D D
25.0 mm 1.00 in. 1 6800 mm 26.1 mm 26.4 mm 3.55
22.4 mm ⁄8 in. 0.875 6700 mm 23.4 mm 23.7 mm 3.56
19.0 mm ⁄4 in. 0.750 6600 mm 19.9 mm 20.1 mm 3.15
16.0 mm ⁄8 in. 0.625 6500 mm 16.7 mm 17.0 mm 3.15
13.2 mm 0.530 in. 0.530 6410 mm 13.83 mm 14.05 mm 2.80
D D
12.5 mm ⁄2in. 0.500 6390 mm 13.10 mm 13.31 mm 2.50
11.2 mm ⁄16 in. 0.438 6350 mm 11.75 mm 11.94 mm 2.50
9.5 mm ⁄8 in. 0.375 6300 mm 9.97 mm 10.16 mm 2.24
8.0 mm ⁄16 in. 0.312 6250 mm 8.41 mm 8.58 mm 2.00
6.7 mm 0.265 in. 0.265 6210 mm 7.05 mm 7.20 mm 1.80
D 1 D
6.3 mm ⁄4in. 0.250 6200 mm 6.64 mm 6.78 mm 1.80
E
5.6 mm No. 3 ⁄2 0.223 6180 mm 5.90 mm 6.04 mm 1.60
4.75 mm No. 4 0.187 6.150 mm 5.02 mm 5.14 mm 1.60
4.00 mm No. 5 0.157 6.130 mm 4.23 mm 4.35 mm 1.40
3.35 mm No. 6 0.132 6.110 mm 3.55 mm 3.66 mm 1.25
2.80 mm No. 7 0.110 6.095 mm 2.975 mm 3.070 mm 1.12
2.36 mm No. 8 0.0937 6.080 mm 2.515 mm 2.800 mm 1.00
2.00 mm No. 10 0.0787 6.070 mm 2.135 mm 2.215 mm 0.900
1.7 mm No. 12 0.0661 6.060 mm 1.820 mm 1.890 mm 0.800
1.4 mm No. 14 0.0556 6.050 mm 1.505 mm 1.565 mm 0.710
1.18 mm No. 16 0.0469 6.045 mm 1.270 mm 1.330 mm 0.830
1.00 mm No. 18 0.0394 6.040 mm 1.080 mm 1.135 mm 0.560
F
850 μm No. 20 0.0331 635 μm 925 μm 970 μm 0.500
710 μm No. 25 0.0278 630 μm 775 μm 815 μm 0.450
600 μm No. 30 0.0234 625 μm 660 μm 695 μm 0.400
500 μm No. 35 0.0197 620 μm 550 μm 585 μm 0.315
425 μm No. 40 0.0165 619 μm 471 μm 502 μm 0.280
355 μm No. 45 0.0139 616 μm 396 μm 426 μm 0.224
300 μm No. 50 0.0117 614 μm 337 μm 363 μm 0.200
250 μm No. 60 0.0098 612 μm 283 μm 306 μm 0.160
212 μm No. 70 0.0083 610 μm 242 μm 263 μm 0.140
180 μm No. 80 0.0070 69 μm 207 μm 227 μm 0.125
150 μm No. 100 0.0059 68 μm 174 μm 192 μm 0.100
125 μm No. 120 0.0049 67 μm 147 μm 163 μm 0.090
106 μm No. 140 0.0041 66 μm 126 μm 141 μm 0.071
90 μm No. 170 0.0035 65 μm 108 μm 122 μm 0.063
75 μm No. 200 0.0029 65 μm 91 μm 103 μm 0.050
63 μm No. 230 0.0025 64 μm 77 μm 89 μm 0.045
53 μm No. 270 0.0021 64 μm 66 μm 76 μm 0.036
45 μm No. 325 0.0017 63 μm 57 μm 66 μm 0.032
38 μm No. 400 0.0015 63 μm 48 μm 57 μm 0.030
32 μm No. 450 0.0012 63 μm 42 μm 50 μm 0.028
D
25 μm No. 500 0.0010 63 μm 34 μm 41 μm 0.025
D
20 μm No. 635 0.0008 63 μm 29 μm 35 μm 0.020
A
Only approximately equivalent to the metric values in Column 1.
B
The average diameter of the wires in the x and y direction, measured separately, of any wire cloth shall not deviate from the nominal values by more than 615 %.
C
These standard designations correspond to the values for test sieve openings recommended by the International Standards Organization, Geneva, Switzerland, except
where noted.
D
These sieves are not in the standard series, but they have been included because they are in common usage.
E
These numbers (3 ⁄2 to 635) are the approximate number of openings per linear inch, but it is preferred that the sieve be identified by the standard designation in
millimetres or micrometres.
F
1000 μm—1 mm.
D 1921
6.4.1 Brush , blinded if it is holding 20 or more g. For repeatable results, use
6.4.2 Vacuum Cleaner, and a smaller sample size.
6.4.3 Air Hose.
NOTE 3—For some materials an antistat (or slip agent) is needed. Add
1% of the antistat (or slip agent) to the sample and mix in with a spatula.
7. Reagents and Materials
State in the report the agent used. With polyvinyl chloride resins, it has
been found that the distribution will skew to either the fine or the coarse
7.1 Antistat (or slip) agent suitable to the material being
particle size depending on the antistat used. Record the antistat (or slip
tested.
agent) used.
8.
...