1、Designation: D6290 051D6290 13Standard Test Method forColor Determination of Plastic Pellets1This standard is issued under the fixed designation D6290; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A nu
2、mber in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1 NOTEAdded research report information to Section 10 editorially in September 2010.1. Scope*1.1 This test method is intended primarily for the instr
3、umental measurement of the degree of yellowness (or change of degreeof yellowness) under daylight illumination of homogeneous, nonfluorescent, nearly-colorless transparent or nearly-whitetranslucent or opaque plastics. The measurement is made on pellets and based on tristimulus values obtained with
4、aspectrophotometer or colorimeter.1.2 This test method is applicable to the color analysis of plastic pellets. Each material mayIt is possible that each material willhave unique characteristics that determine the color values.1.3 This procedure outlines a method to determine color measurements, such
5、 as Yellowness Index, CIE X, Y, Z, and Hunter L,a, b, or CIE L*, a*, b*.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine t
6、he applicability of regulatorylimitations prior to use.NOTE 1There is no equivalent ISO Standard.known ISO equivalent to this standard.2. Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD2244 Practice for Calculation of Color Tolerances and Color Differences from Instrum
7、entally Measured Color CoordinatesE179 Guide for Selection of Geometric Conditions for Measurement of Reflection and Transmission Properties of MaterialsE284 Terminology of AppearanceE308 Practice for Computing the Colors of Objects by Using the CIE SystemE313 Practice for Calculating Yellowness and
8、 Whiteness Indices from Instrumentally Measured Color CoordinatesE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE1331 Test Method for Reflectance Factor and Color by Spectrophotometry Using Hemispherical GeometryE1347 Test Method for Color and Color-
9、Difference Measurement by Tristimulus ColorimetryE1349 Test Method for Reflectance Factor and Color by Spectrophotometry Using Bidirectional (45:0 or 0:45) Geometry3. Terminology3.1 Definitions Refer to Terminologies D883 and E284 for definitions of terms used in this test method.4. Significance and
10、 Use4.1 Before proceeding with this test method, make reference should be made to the specification of the material being tested.Any test specimen preparation, conditioning, dimensions, or testing parameters, or a combination thereof, covered in the materialsspecification shall take precedence over
11、those mentioned in this test method. If there are no material specifications, then defaultconditions apply.NOTE 2Some materials, such as polyamide (nylon), can be cooled very differently during the production of the pellets. This variation in the cooling1 This test method is under the jurisdiction o
12、f ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.40 on Optical Properties.Current edition approved April 1, 2005Nov. 1, 2013. Published June 2005November 2013. Originally approved in 1998. Last previous edition approved in 19982005 asD6290 - 98D6290 - 051. DOI: 1
13、0.1520/D6290-05E01.10.1520/D6290-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an A
14、STM 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. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In
15、all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1of the p
16、ellets can result in different levels of crystallinity in the pellets only. More crystalline nylons will be more opaque than amorphous nylons. Thiswill result in differences in pellet opacity. The pellet shape is independent of the crystallinity of the material. This variation in pellet appearance,
17、due tovarying levels of crystallinity, does not affect final properties.NOTE 3This test method should not be used for general material specifications.4.2 This test method describes a technique useful for making color comparisons of resins in pellet form that is fast andconvenient as it does not requ
18、ire preparation, such as molding or extruding specimens. The test method shall be used only tocompare specimens of similar pellet shape, size, texture, and degree of translucency. For example, compare translucent disc-shapedpellets should be compared to translucent disc-shaped pellets, not with opaq
19、ue, rectangular shaped pellets.4.3 Exact measurements of resin pellet color mayare not benecessarily directly related to the color of the final cast, molded orextruded product due to the multitude of variables, such as producing variables, methods, and pellet shape and size. Colormeasurements can be
20、 useful for comparing resins in pellet form when all samples are similar in shape and size.4.4 Athree-number tristimulus system is necessary to quantify color completely and precisely. The general method used in thisprocedure measures color using the CIE Systems described in Practice E308, Test Meth
21、od D2244, the CIE 1976 (X, Y, Z) system,and, the CIELAB 1976 color space.34.5 Individual components of the tristimulus measurement such as CIE Y (Luminance), Hunter L, a, b, or CIE L*, a*, b* valuesor other useful metrics like yellowness index can be used to describe color attributes of materials. T
22、his test method describes astandard procedure on how these measurements are made.5. Interferences5.1 Comparisons of color measurements can only be made if the material is the same, the pellet cut, size and shape areessentially the same and the test instrument is the same type and within the same gro
23、up. (See 6.2 and Section 10 and TablesAandB for instrument differences.)6. Apparatus6.1 Apparatus may be Choices of apparatus include spectrophotometer, or tristimulus colorimeter, conforming to Guide E179.6.2 There are several different optical geometries currently being used for measuring color. I
24、t is important that similar opticalgeometries be used if results are to be compared. These are designated as Groups defined as follows:6.2.1 Group ISpectrophotometer with 45 to 52-mm port with 0/45 directional geometry. See Test Methods E1347 and E1349.6.2.2 Group IIColorimeter with 31 to 52-mm port
25、 with 45/0 directional geometry. See Test Methods E1347 and E1349.6.2.3 Group IIISphere with minimum of 25-mm port with a nominal 0/diffuse geometry. See Test Methods E1331 and E1347.6.2.4 Group IVSphere with minimum of 25-mm port with a nominal diffuse/0 geometry. See Test Methods E1331 and E1347.6
26、.3 There may be other Other optical geometries being are potentially used for this test method, which should they need to beadded if being used and brought to our attention as this procedure is being evaluated.6.4 Calibrated tiles, for instrument standardization.6.5 Glass (clear), specimen cell at l
27、east 60-mm 2(2 12-in.-in.) diameter and a minimum of 50-mm depth and black samplecover of sufficient size to prevent external light from affecting the pellet measurement.NOTE 4The clear sample holder may be any shape that is larger than the port with at least 6-mm between the edge of the port and th
28、e edge of thesample holder.7. Procedure7.1 Standardize the instrument in accordance with the manufacturers written instructions (usually once per shift).7.2 Fill the sample cup to the top with pellets.7.3 Center the pellet filled cup at the sensor port for measurement. Use a centering device if one
29、is provided by the manufacturer.7.4 Cover the sample cup with an opaque, light exclusion device or cover.7.5 For Yellowness Index make, the necessary readings of Tristimulus X, Y, Z to determine Yellowness Index as described inTest Method E313 as soon as possible using illuminant “C”, specular exclu
30、ded, and CIE 1931 2 observer.NOTE 5Care must be taken not to allow the pellet sample to remain at the measurement port for a long period of time prior to measurement. Lightexposure of high intensity may cause yellowness to change, thus altering the test value.NOTE 6Many instruments will report the Y
31、ellowness Index in accordance with Test Method E313 directly thus no calculations are required forindividual Yellowness Index value.3 Based upon the Colorimetry, 2nd ed., Publication CIE No. 15.2, Central Bureau of the CIE, Vienna, 1986. Currently available through the U.S. National Committee ofthe
32、CIE, % Mr. Thomas Lemmons, TLA Lighting Consultants, Inc., 7 Pond St., Salem, MA 019704819.D6290 1327.5.1 For other measurements, such as Hunter L, a, b or CIE L*, a*, b* make the necessary instrument settings and take thereadings.7.6 Repeat steps 7.2 through 7.5.1 two more times for a total of thre
33、e results.8. Calculation8.1 Determine the average yellowness index, YI, if requested, using the following formula:YI5100 CxX 2CzZ!/Y (1)where:Cx = 1.2769, andCz = 1.0592.8.2 Determine the average yellowness index by summing the test values and divide by the number of samples tested.9. Report9.1 Repo
34、rt the following information:9.1.1 Average of the Yellowness Index or other measurements if noted,9.1.2 Sample identification, such as lot number, source, etc.,9.1.3 Date test was conducted,9.1.4 The instrument group or geometry, and9.1.5 The instrument used including name of manufacturer, model, an
35、d serial number.10. Precision and Bias410.1 Precision:10.1.1 Table 1 reflects data tested with ten instruments in Group I, and Table 2with six instruments in Group II. All data arebased on a round robin conducted in 1994-1995 in accordance with Practice E691, involving eight materials tested with si
36、x testresults measured on three days by each laboratory. For each material, pellets were gathered and packaged by one source and theindividual packages were sent to each of the laboratories which tested them. Each test result is the value of an individual4 Supporting data have been filed at ASTM Int
37、ernational Headquarters and may be obtained by requesting Research Report RR:D20-1235.TABLE 1 Yellowness Index of PelletsApparatus Group IMaterial Average SrA SRB rC RDMaterial G 3.99 0.206 0.495 0.576 1.385Material B 0.33 0.130 0.424 0.363 1.188Material F 0.133 0.113 0.524 0.317 1.467Material H 0.5
38、38 0.076 0.443 0.214 1.241Material C 1.539 0.095 0.398 0.267 1.116Material E 8.82 0.376 1.840 1.052 5.153Material A 15.8 0.365 0.877 1.023 2.455Material D 24.6 0.139 0.860 0.390 2.409TABLE 1A Yellowness Index of PelletsEstimate for Three Specimens (Apparatus Group I)Material Average SrA SRB rC RDMat
39、erial G 3.99 0.092 0.459 0.258 1.286Material B 0.33 0.058 0.408 0.162 1.143Material F 0.133 0.051 0.514 0.142 1.439Material H 0.538 0.034 0.438 0.096 1.226Material C 1.539 0.043 0.389 0.119 1.090Material E 8.82 0.168 1.809 0.470 5.067Material A 15.8 0.163 0.813 0.458 2.278Material D 24.6 0.062 0.851
40、 0.174 2.383ASr is the within-laboratory standard deviation or the indicated material. It isobtained by pooling the within-laboratory standard deviations of the test resultsfrom all of the participating laboratories:S r 5ffss1d21ss2d22221ssnd2g/ng1/2BSR is the between-laboratories reproducibility, e
41、xpressed as standard deviation:SR5fSr21SL2g1/2where: SL is the standard deviation of laboratory means.Cr is the within-laboratory critical interval between two test results = 2.8 Sr.DR is the between-laboratories critical interval between two test results = 2.8 SR.D6290 133determination. Each labora
42、tory obtained six test results for each materials. Table 1A and Table 2B reflect the values as if each testTABLE 2 Yellowness Index of PelletsApparatus Group IIMaterial Average SrA SRB rC RDMaterial G 5.32 0.361 1.01 1.01 2.82Material F 1.85 0.177 0.838 0.495 2.35Material H 1.64 0.138 0.512 0.387 1.
43、43Material B 1.61 0.152 0.646 0.425 1.81Material C 0.126 0.220 0.507 0.617 1.42Material E 7.21 0.289 2.20 0.810 6.15Material A 13.3 0.352 2.01 0.986 5.63Material D 20.6 0.167 1.45 0.468 4.07TABLE 2A Yellowness Index of PelletsEstimate for Three Specimens (Apparatus Group II)Material Average SrA SRB
44、rC RDMaterial G 5.32 0.161 0.908 0.452 2.54Material F 1.85 0.079 0.823 0.173 2.31Material H 1.64 0.062 0.497 0.173 1.39Material B 1.61 0.068 0.632 0.190 1.77Material C 0.126 0.098 0.467 0.276 1.31Material E 7.21 0.129 2.18 0.362 6.11Material A 13.3 0.158 1.98 0.441 5.56Material D 20.6 0.075 1.44 0.2
45、09 4.05ASr is the within-laboratory standard deviation or the indicated material. It isobtained by pooling the within-laboratory standard deviations of the test resultsfrom all of the participating laboratories:Sr5ffss1d21ss2d22221ssnd2g/ng1/2BSR is the between-laboratories reproducibility, expresse
46、d as standard deviation:SR5fSr21SL2g1/2where: SL is the standard deviation of laboratory means.Cr is the within-laboratory critical interval between two test results = 2.8 Sr.DR is the between-laboratories critical interval between two test results = 2.8 SR.TABLE 3 Yellowness Index of PelletsAll App
47、aratus GroupsMaterial Average SrA SRB rC RDMaterial G 4.69 1.04 1.45 2.92 4.05Material F 1.61 1.06 1.91 2.96 5.36Material B 0.979 0.504 1.03 1.41 2.88Material H 0.014 4.13 4.13 11.6 11.6Material C 2.08 5.77 5.77 16.2 16.2Material E 6.51 2.45 3.77 6.87 10.6Material A 12.7 3.78 4.87 10.6 13.6Material
48、D 20.7 3.94 5.50 11.0 15.4TABLE 3A Yellowness Index of PelletsEstimate for Three SpecimensAll Apparatus GroupsMaterial Average SrA SRB rC RDMaterial G 4.69 0.466 1.11 1.30 3.10Material F 1.61 0.473 1.66 1.33 4.66Material B 0.979 0.226 0.925 0.632 2.59Material H 0.014 1.85 1.85 5.17 5.17Material C 2.
49、08 2.58 2.58 7.23 7.23Material E 6.51 1.10 3.07 3.07 8.60Material A 12.7 1.69 3.50 4.73 9.81Material D 20.7 1.76 4.23 4.93 4.23ASr is the within-laboratory standard deviation or the indicated material. It isobtained by pooling the within-laboratory standard deviations of the test resultsfrom all of the participating laboratories:Sr5ffss1d21ss2d22221ssnd2g/ng1/2BSR is the between-laboratories reproducibility, expressed as standard deviation:SR5fSr21SL2g1/2where: SL is the standard deviation of laboratory means.Cr is the withi
