1、Designation: D 1921 06Standard Test Methods forParticle Size (Sieve Analysis) of Plastic Materials1This standard is issued under the fixed designation D 1921; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisio
2、n. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 These test methods cover the measurement of the
3、particle size of plastic materials in the powdered, granular, orpelleted forms in which they are commonly supplied. As thesetest methods utilize dry sieving, the lower limit of measure-ment is considered to be about 38 m (No. 400 sieve). Forsmaller particle sizes, sedimentation test methods are reco
4、m-mended.1.2 Two test methods are described:1.2.1 Test Method AThis test method uses multiple sievesselected to span the particle size of the material. This methodis used to determine the mean particle diameter and particlesize distribution.1.2.2 Test Method BThis test method is an abbreviatedversio
5、n of Test Method A conducted with a few specific sieves.This test method determines “percent passing” or “percentretained” on a given sieve. Test Method B is applicable tomaterials which do not have a normal particle size distributionsuch as pellets and cubes.1.3 The values stated in SI units shall
6、be consideredstandard for dimensions of the wire cloth openings and thediameter of the wires used in the wire cloth. The values statedin inch-pound units shall be considered standard with regard tothe sieve frames.1.4 This standard does not purport to address all of thesafety concerns, if any, assoc
7、iated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE 1There is no technically equivalent ISO standard.2. Referenced Documents2.1 ASTM Standards:2E11
8、Specification for Wire Cloth and Sieves for TestingPurposesE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Summary of Test Methods3.1 A dry mass of plastic material is placed on a series ofsieves arranged in order of increasing fineness and the mas
9、s isdivided into fractions corresponding to the sieve opening.4. Significance and Use4.1 These test methods can be used to determine particlesize distribution and therefore are useful for determininglot-to-lot uniformity.4.2 The particle sizes of plastic materials affect the handlingcharacteristics
10、and sometimes will affect the processing char-acteristics of some polymers.5. Interferences5.1 Some materials develop a static charge during sieving.This charge interferes with the sieving process and results in acoarse bias. Use of an antistat is necessary to obtain meaning-ful results.5.2 The choi
11、ce of antistat (or slip agent) has been known toaffect the coarse bias. Some materials are more effective inaiding the fines to separate from the mass.5.3 Too much material on a sieve causes mass blinding andresults in a coarse bias. The sieve selection and charge weightmust be chosen to avoid overl
12、oading any sieve.1These test methods are under the jurisdiction of ASTM Committee D20 onPlastics and are the direct responsibility of Subcommittee D20.70 on AnalyticalMethods (Section D20.70.01).Current edition approved April 1, 2006. Published June 2006. Originallyapproved in 1961. Last previous ed
13、ition approved in 2001 as D 1921 - 01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes
14、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.5.4 Wavy, improperly stretched wire-cloth may allow wiresto separate without being visually damaged. Sieves with wavyor torn wires shall not b
15、e used, as they no longer conform toSpecification E11.6. Apparatus6.1 Balance, 500-g minimum capacity with the capability ofreading to the nearest 0.1 g.6.2 Mechanical Sieving Device and Time SwitchA me-chanical sieve-shaking device equipped with an automatic timeswitch. This device shall be capable
16、 of imparting uniformrotary motion and a tapping action at a rate of 150 6 10taps/min.6.3 Wire Cloth Sieves, woven wire cloth conforming toSpecification E11, as shown in Table 1, mounted in 8-in.203-mm frames. The number of sieves and the choice of sizesshall be selected for the material being teste
17、d. A cover and abottom pan are also required.6.4 Accessories for Cleaning the Screens:6.4.1 Brush3,6.4.2 Vacuum Cleaner, and6.4.3 Air Hose.7. Reagents and Materials7.1 Antistat (or slip) agent suitable to the material beingtested.8. Hazards8.1 The sieving operation and cleaning of the sieves some-ti
18、mes introduce fine plastic particles and antistat agent into theatmosphere. Take precautions to avoid breathing these par-ticles.9. Sampling9.1 Homogenize the lot where possible before removing thetest sample to avoid segregation of particles during handling.10. Preparation of Apparatus10.1 Thorough
19、 cleaning and inspection of the sieve arerequired prior to initiating a test. Carefully clean the sieveswith a brush and vacuum cleaner or compressed air, or both.Periodic washing with soap and water or suitable solvent isrecommended with some materials.10.2 Tare each sieve and the pan. Record tare
20、weights to thenearest 0.1 g.10.3 Assemble sieves so that the sieve openings decrease insize in sequence from the top of the stack. Place the pan at thebottom.10.4 Use full- or half-size screens to accommodate theholder in the shaker.11. Conditioning11.1 The plastic material must be in a free-flowing
21、 condi-tion.11.2 If possible, condition the material to the laboratorytemperature and humidity.TEST METHOD A12. Procedure12.1 Select sieves in sufficient number to cover the expectedrange of particle sizes, and nest them together in order ofdiminishing opening with the coarsest sieve on top and the
22、panon the bottom.12.2 Select sieves in sufficient number to have significantmeasurable quantities on four or more sieves. Weigh the sieveson a balance reading to the nearest 0.1 g. Record these sievemasses as their tare masses, respectively.12.3 Weigh 50 g of sample to the nearest 0.1 g and transfer
23、it to the top of the stack. Record the sample weight used. Largesample size causes screen blinding and will skew the results tothe coarse particle size. A screen is considered blinded if it isholding 20 or more g. For repeatable results, use a smallersample size.NOTE 2For some materials an antistat
24、(or slip agent) is needed. Add1 % of the antistat (or slip agent) to the sample and mix in with a spatula.With polyvinyl chloride resins, it has been found that the distribution willskew to either the fine or the coarse particle size depending on the antistatused. Record the antistat (or slip agent)
25、 used.12.4 Cover the stack and place it in the mechanical sieveshaker. Start the shaker and run for 10 min. Run the shaker fora longer time if it is required by the material and the efficiencyof the shaker.12.5 After shaking, carefully separate the stack of sieves,beginning at the top, and weigh eac
26、h sieve with powder to thenearest 0.1 g. Determine the net weight of the powderremaining in each sieve by subtracting the sieve tare massesfrom the total weight of the sieve and the powder in that sieve.12.6 If the cumulative total of actual weight is less than98 %, carefully check the weights and o
27、perations and repeatthe work if necessary.13. Analysis of Particle Distribution13.1 Calculation of Particle Distribution:13.1.1 Obtain net weight of material retained on each sieve.Calculate percentage by dividing net weight by total sampleweight 3 100.13.1.2 Repeat for each sieve.13.2 Calculation o
28、f Mean Particle Size:13.2.1 Obtain net weight of material retained on each sieve.13.2.2 Determine an average particle size for each sieve.The average particle size is defined as the nominal opening sizeof that sieve plus the nominal opening size of the next largersieve in the stack divided by two.NO
29、TE 3Options are recommended to determine the average mesh sizeof the top sieve and the pan. On the coarse end, if the particles havealready been through a coarser screen, the screen size of the “throughscreen” can be used as the upper limit of the top screen (first screen). Acommonly used method is
30、to place a set of sieves with openings greaterthan the desired top sieve. Select the lowest sieve where there is noparticle on or the amount of particles on the sieve is insignificant. Use theopening size of this sieve for calculation. Similar analog can be used to thepan by using smaller opening si
31、eves. A more practical way is to divide the3The sole source of supply of the Type 8577 (W. S. Tyler) Brush known to thecommittee at this time is W. S. Tyler, Inc., 8750 Tyler Blvd., Mentor, OH 44060. Ifyou are aware of alternative suppliers, please provide this information to ASTMInternational Headq
32、uarters. Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.D1921062TABLE 1 Nominal Dimensions, Permissible Variations for Wire Cloth of Standard Test Sieves (U.S.A.) Standard SeriesSieve DesignationNominal SieveOpening, in.APerm
33、issibleVariation ofAverage Openingfrom the StandardSieve DesignationOpening DimensionExceeded By NotMore Than 5 % ofthe OpeningsMaximumIndividual OpeningNominal WireDiameter, mmBStandardCAlternative(1) (2) (3) (4) (5) (6) (7)125 mm 5 in. 5 63.70 mm 130.0 mm 130.9 mm 8.00106 mm 4.24 in. 4.24 63.20 mm
34、 110.2 mm 111.1 mm 6.30100 mmD4in.D4 63.00 mm 104.0 mm 104.8 mm 6.3090 mm 312 in. 3.5 62.70 mm 93.6 mm 94.4 mm 6.3075 mm 3 in. 3 62.20 mm 78.1 mm 78.7 mm 6.3063 mm 212 in. 2.5 61.90 mm 65.6 mm 66.2 mm 5.8053 mm 2.12 in. 2.12 61.60 mm 55.2 mm 55.7 mm 5.0050 mmD2in.D2 61.50 mm 52.1 mm 52.6 mm 5.0045 m
35、m 134 in. 1.75 61.40 mm 46.9 mm 47.4 mm 4.5037.5 mm 112 in. 1.5 61.10 mm 39.1 mm 39.5 mm 4.5031.5 mm 114 in. 1.25 61.00 mm 32.9 mm 33.2 mm 4.0026.5 mm 1.06 in. 1.06 6800 mm 27.7 mm 28.0 mm 3.5525.0 mmD1.00 in.D1 6800 mm 26.1 mm 26.4 mm 3.5522.4 mm78 in. 0.875 6700 mm 23.4 mm 23.7 mm 3.5619.0 mm34 in
36、. 0.750 6600 mm 19.9 mm 20.1 mm 3.1516.0 mm58 in. 0.625 6500 mm 16.7 mm 17.0 mm 3.1513.2 mm 0.530 in. 0.530 6410 mm 13.83 mm 14.05 mm 2.8012.5 mmD 12 in.D0.500 6390 mm 13.10 mm 13.31 mm 2.5011.2 mm716 in. 0.438 6350 mm 11.75 mm 11.94 mm 2.509.5 mm38 in. 0.375 6300 mm 9.97 mm 10.16 mm 2.248.0 mm516 i
37、n. 0.312 6250 mm 8.41 mm 8.58 mm 2.006.7 mm 0.265 in. 0.265 6210 mm 7.05 mm 7.20 mm 1.806.3 mmD 14 in.D0.250 6200 mm 6.64 mm 6.78 mm 1.805.6 mm No. 312E0.223 6180 mm 5.90 mm 6.04 mm 1.604.75 mm No. 4 0.187 6.150 mm 5.02 mm 5.14 mm 1.604.00 mm No. 5 0.157 6.130 mm 4.23 mm 4.35 mm 1.403.35 mm No. 6 0.
38、132 6.110 mm 3.55 mm 3.66 mm 1.252.80 mm No. 7 0.110 6.095 mm 2.975 mm 3.070 mm 1.122.36 mm No. 8 0.0937 6.080 mm 2.515 mm 2.800 mm 1.002.00 mm No. 10 0.0787 6.070 mm 2.135 mm 2.215 mm 0.9001.7 mm No. 12 0.0661 6.060 mm 1.820 mm 1.890 mm 0.8001.4 mm No. 14 0.0556 6.050 mm 1.505 mm 1.565 mm 0.7101.18
39、 mm No. 16 0.0469 6.045 mm 1.270 mm 1.330 mm 0.8301.00 mm No. 18 0.0394 6.040 mm 1.080 mm 1.135 mm 0.560850 mFNo. 20 0.0331 635 m 925 m 970 m 0.500710 m No. 25 0.0278 630 m 775 m 815 m 0.450600 m No. 30 0.0234 625 m 660 m 695 m 0.400500 m No. 35 0.0197 620 m 550 m 585 m 0.315425 m No. 40 0.0165 619
40、m 471 m 502 m 0.280355 m No. 45 0.0139 616 m 396 m 426 m 0.224300 m No. 50 0.0117 614 m 337 m 363 m 0.200250 m No. 60 0.0098 612 m 283 m 306 m 0.160212 m No. 70 0.0083 610 m 242 m 263 m 0.140180 m No. 80 0.0070 69 m 207 m 227 m 0.125150 m No. 100 0.0059 68 m 174 m 192 m 0.100125 m No. 120 0.0049 67
41、m 147 m 163 m 0.090106 m No. 140 0.0041 66 m 126 m 141 m 0.07190 m No. 170 0.0035 65 m 108 m 122 m 0.06375 m No. 200 0.0029 65 m 91 m 103 m 0.05063 m No. 230 0.0025 64m 77m 89m 0.04553 m No. 270 0.0021 64m 66m 76m 0.03645 m No. 325 0.0017 63m 57m 66m 0.03238 m No. 400 0.0015 63m 48m 57m 0.03032 m No
42、. 450 0.0012 63m 42m 50m 0.02825 mDNo. 500 0.0010 63m 34m 41m 0.02520 mDNo. 635 0.0008 63m 29m 35m 0.020AOnly approximately equivalent to the metric values in Column 1.BThe average diameter of the wires in the x and y direction, measured separately, of any wire cloth shall not deviate from the nomin
43、al values by more than 615 %.CThese standard designations correspond to the values for test sieve openings recommended by the International Standards Organization, Geneva, Switzerland, exceptwhere noted.DThese sieves are not in the standard series, but they have been included because they are in com
44、mon usage.EThese numbers (312 to 635) are the approximate number of openings per linear inch, but it is preferred that the sieve be identified by the standard designation inmillimetres or micrometres.F1000 m1 mm.D1921063opening size of the sieve above the pan by two and use it as the averageparticle
45、 size of the pan.13.2.3 For materials that have a normal distribution, calcu-late the mean particle size asDm5 (Pi3 Di!where:Dm= mean particle diameter, m,Pi= material retained on sieve (or pan), %, andDi= average particle size of material on sieve, m.14. Report14.1 Report the following information:
46、14.1.1 Percentage of material retained on each sieve, withits corresponding sieve size,14.1.2 Sample weight,14.1.3 Antistat (or slip agent) used, and14.1.4 Mean particle size and method used for calculation.TEST METHOD B15. Procedure15.1 Choose the sieve(s) to be used and weigh each of themto the ne
47、arest 0.1 g. Record these sieve masses as their taremasses, respectively. If a single sieve is being used, stack it onthe pan and transfer a sample weighing 100 6 0.1 g to thatsieve. If two sieves are to be used in the analysis of the sample,stack the coarse sieve over the fine sieve and transfer th
48、eweighed sample to the coarse sieve. For those finely dividedpowders which tend to clog the sieves, add 1.0 % of an antistat(see Note 2).15.2 Cover the stack and place it in the mechanical sieveshaker. Start the shaker and run for 10 min 6 15 s.15.3 After shaking, carefully separate the stack of sie
49、ves,beginning at the top, and weigh each sieve with powder to thenearest one tenth of a gram.16. Report16.1 Report the following information:16.1.1 Percentage of material retained on each sieve, withits corresponding sieve size,16.1.2 Sample weight, and16.1.3 Antistat (or slip agent) used.17. Precision and Bias17.1 PrecisionTable 2 and Table 3 are based on a roundrobin conducted in 1985 in accordance with Practice E 691,using D 1921 89, involving four materials tested
