1、Designation: D 6290 05Standard Test Method forColor Determination of Plastic Pellets1This standard is issued under the fixed designation D 6290; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in
2、 parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method is intended primarily for the instru-mental measurement of the degree of yellowness (or change ofdegree of yellowness) under
3、daylight illumination of homoge-neous, nonfluorescent, nearly-colorless transparent or nearly-white translucent or opaque plastics. The measurement is madeon pellets and based on tristimulus values obtained with aspectrophotometer or colorimeter.1.2 This test method is applicable to the color analys
4、is ofplastic pellets. Each material may have unique characteristicsthat determine the color values.1.3 This procedure outlines a method to determine colormeasurements, such as Yellowness Index, CIE X, Y, Z, andHunter L, a, b, or CIE L*, a*, b*.1.4 This standard does not purport to address all of the
5、safety concerns, if any, associated 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 equivalent ISO Standard.2. Referenced Documents2.1 AS
6、TM Standards:2D 883 Terminology Relating to PlasticsD 2244 Test Method for Calculation of Color Differencesfrom Instrumentally Measured Color CoordinatesE 179 Guide for Selection of Geometric Conditions forMeasurement of Reflection and Transmission Properties ofMaterialsE 284 Terminology of Appearan
7、ceE 308 Practice for Computing the Colors of Objects byUsing the CIE SystemE 313 Test Method for Indexes of Whiteness and Yellow-ness of Near-White Opaque MaterialsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE 1331 Test Method for Reflectance Fact
8、or and Color bySpectrophotometry Using Hemispherical GeometryE 1347 Test Method for Color and Color-Difference Mea-surement by Tristimulus (Filter) ColorimetryE 1349 Test Method for Reflectance Factor and Color bySpectrophotometry Using Bidirectional Geometry3. Terminology3.1 Definitions Refer to Te
9、rminologies D 883 and E 284for definitions of terms used in this test method.4. Significance and Use4.1 Before proceeding with this test method, referenceshould be made to the specification of the material being tested.Any test specimen preparation, conditioning, dimensions, ortesting parameters, or
10、 a combination thereof, covered in thematerials specification shall take precedence over those men-tioned in this test method. If there are no material specifica-tions, then default conditions apply.NOTE 2Some materials, such as polyamide (nylon), can be cooledvery differently during the production
11、of the pellets. This variation in thecooling of the pellets can result in different levels of crystallinity in thepellets only. More crystalline nylons will be more opaque than amorphousnylons. This will result in differences in pellet opacity. The pellet shape isindependent of the crystallinity of
12、the material. This variation in pelletappearance, due to varying levels of crystallinity, does not affect finalproperties.NOTE 3This test method should not be used for general materialspecifications.4.2 This test method describes a technique useful for mak-ing color comparisons of resins in pellet f
13、orm that is fast andconvenient as it does not require preparation, such as moldingor extruding specimens. The test method shall be used only tocompare specimens of similar pellet shape, size, texture, anddegree of translucency. For example, translucent disc-shapedpellets should be compared to transl
14、ucent disc-shaped pellets,not with opaque, rectangular shaped pellets.4.3 Exact measurements of resin pellet color may not bedirectly related to the color of the final cast, molded orextruded product due to the multitude of variables, such asproducing variables, methods, and pellet shape and size. C
15、olor1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.40 on Optical Properties.Current edition approved April 1, 2005. Published June 2005. Originallyapproved in 1998. Last previous edition approved in 1998 as D 6290 - 9
16、8e1.2For 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 section appears at the end of this
17、 standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.measurements can be useful for comparing resins in pellet formwhen all samples are similar in shape and size.4.4 A three-number tristimulus system is necessary to quan-tify col
18、or completely and precisely. The general method used inthis procedure measures color using the CIE Systems describedin Practice E 308, Test Method D 2244, the CIE 1976 (X, Y, Z)system, and, the CIELAB 1976 color space.34.5 Individual components of the tristimulus measurementsuch as CIE Y (Luminance)
19、, Hunter L, a, b, or CIE L*, a*, b*values or other useful metrics like yellowness index can beused to describe color attributes of materials. This test methoddescribes a standard procedure on how these measurements aremade.5. Interferences5.1 Comparisons of color measurements can only be madeif the
20、material is the same, the pellet cut, size and shape areessentially the same and the test instrument is the same typeand within the same group. (See 6.2 and Section 10 and TablesA and B for instrument differences.)6. Apparatus6.1 Apparatus may be spectrophotometer, or tristimuluscolorimeter, conform
21、ing to Guide E 179.6.2 There are several different optical geometries currentlybeing used for measuring color. It is important that similaroptical geometries be used if results are to be compared. Theseare designated as Groups defined as follows:6.2.1 Group ISpectrophotometer with 45 to 52-mm portwi
22、th 0/45 directional geometry. See Test Methods E 1347 andE 1349.6.2.2 Group IIColorimeter with 52-mm port with 45/0directional geometry. See Test Methods E 1347 and E 1349.6.2.3 Group IIISphere with minimum of 25-mm port witha nominal 0/diffuse geometry. See Test Methods E 1331 andE 1347.6.2.4 Group
23、 IVSphere with minimum of 25-mm port witha nominal diffuse/0 geometry. See Test Methods E 1331 andE 1347.6.3 There may be other optical geometries being used forthis test method, which should be added if being used andbrought to our attention as this procedure is being evaluated.6.4 Calibrated tiles
24、, for instrument standardization.6.5 Glass (clear), specimen cell at least 60-mm 212-in.diameter and a minimum of 50-mm depth and black samplecover of sufficient size to prevent external light from affectingthe pellet measurement.NOTE 4The clear sample holder may be any shape that is larger thanthe
25、port with at least 6-mm between the edge of the port and the edge ofthe sample holder.7. Procedure7.1 Standardize the instrument in accordance with themanufacturers 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 s
26、ensor port formeasurement. Use a centering device if one is provided by themanufacturer.7.4 Cover the sample cup with an opaque, light exclusiondevice or cover.7.5 For Yellowness Index make, the necessary readings ofTristimulus X,Y, Z to determineYellowness Index as describedin Test Method E 313 as
27、soon as possible using illuminant “C”,specular excluded, and CIE 1931 2 observer.NOTE 5Care must be taken not to allow the pellet sample to remainat the measurement port for a long period of time prior to measurement.Light exposure of high intensity may cause yellowness to change, thusaltering the t
28、est value.NOTE 6Many instruments will report the Yellowness Index in accor-dance with Test Method E 313 directly thus no calculations are requiredfor individual Yellowness Index value.7.5.1 For other measurements, such as Hunter L, a, b or CIEL*, a*, b* make the necessary instrument settings and tak
29、e thereadings.7.6 Repeat steps 7.2 through 7.5.1 two more times for a totalof three results.8. Calculation8.1 Determine the average yellowness index, YI, if re-quested, using the following formula:YI 5 100 CxX CzZ!/Y (1)where:Cx= 1.2769, andCz= 1.0592.8.2 Determine the average yellowness index by su
30、mmingthe test values and divide by the number of samples tested.9. Report9.1 Report the following information:9.1.1 Average of the Yellowness Index or other measure-ments 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 o
31、r geometry, and9.1.5 The instrument used including name of manufacturer,model, and serial number.10. Precision and Bias10.1 Precision:10.1.1 Table 1 reflects data tested with ten instruments inGroup I, and Table 2 with six instruments in Group II. All dataare based on a round robin conducted in 1994
32、-1995 inaccordance with Practice E 691, involving eight materialstested with six test results measured on three days by eachlaboratory. For each material, pellets were gathered and pack-aged by one source and the individual packages were sent toeach of the laboratories which tested them. Each test r
33、esult isthe value of an individual determination. Each laboratoryobtained six test results for each materials. Table 1A and Table2B reflect the values as if each test value consisted of anaverage of three readings. (WarningThe following explana-tions of r and R (10.1.2 through 10.1.4) only are inten
34、ded to3Based upon the Colorimetry, 2nded., Publication CIE No. 15.2, Central Bureauof the CIE, Vienna, 1986. Currently available through the U.S. National Committeeof the CIE, % Mr. Thomas Lemmons, TLA Lighting Consultants, Inc., 7 Pond St.,Salem, MA 019704819.D6290052present a meaningful way of con
35、sidering approximate preci-sion of this test method. The data in Table 1, Table 2, Table 1A,and Table 2A should not be applied rigorously to acceptance orrejection of material, as those data are specific to the roundrobin and may not be representative of other lots, conditions,materials, or laborato
36、ries. Users of this test method shouldapply the principles outlined in Practice E 691 to generate dataspecific to their laboratory and materials or between specificlaboratories. The principles of 10.1.2 through 10.1.4 thenwould be valid for such data.)10.1.2 Concept of r and RIf Srand SRhave been ca
37、lcu-lated from a large enough body of data and for test results thatare the result of testing one specimen:10.1.3 Repeatability Limit, r (Comparing two test results forthe same material, obtained by the same operator using thesame equipment on the same day)The two test results shouldbe judged not eq
38、uivalent if they differ by more than the r valuefor that material.10.1.4 Reproducibility Limit, R (Comparing two test resultsfor the same material, obtained by different operators usingdifferent equipment in different laboratories)The two testresults should be judged not equivalent if they differ by
39、 morethan the R value for that material.10.1.5 Any judgment in accordance with 10.1.1 or 10.1.2would have an approximate 95 % (0.95) probability of beingcorrect.10.2 BiasThere are no recognized standards by which toestimate bias of this test method.11. Keywords11.1 color; pellets; plastics; yellowne
40、ss; yellowness indexTABLE 1 Yellowness Index of PelletsApparatus Group IMaterial Average SrASRBrCRDMaterial 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 0.538 0.076 0.443 0.214 1.241Material C 1.539 0.095 0.398 0.267 1.116Mat
41、erial 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 SrASRBrCRDMaterial G 3.99 0.092 0.459 0.258 1.286Material B 0.33 0.058 0.408 0.162 1.
42、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 0.174 2.383ASris the within-laboratory standard deviation or the indica
43、ted material. It isobtained by pooling the within-laboratory standard deviations of the test resultsfrom all of the participating laboratories:Sr5 s1!21 s2!22221sn!2#/n1/2BSRis the between-laboratories reproducibility, expressed as standard devia-tion:SR5 Sr21 SL2#1/2where: SLis the standard deviati
44、on of laboratory means.Cr is the within-laboratory critical interval between two test results = 2.8 3 Sr.DR is the between-laboratories critical interval between two test results = 2.8 3SR.TABLE 2 Yellowness Index of PelletsApparatus Group IIMaterial Average SrASRBrCRDMaterial G 5.32 0.361 1.01 1.01
45、 2.82Material F 1.85 0.177 0.838 0.495 2.35Material H 1.64 0.138 0.512 0.387 1.43Material 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 Pe
46、lletsEstimate for Three Specimens (Apparatus Group II)Material Average SrASRBrCRDMaterial 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
47、.362 6.11Material A 13.3 0.158 1.98 0.441 5.56Material D 20.6 0.075 1.44 0.209 4.05ASris 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:Sr5 s1!21 s2!2
48、2221sn!2#/n1/2BSRis the between-laboratories reproducibility, expressed as standard devia-tion:SR5 Sr21 SL2#1/2where: SLis the standard deviation of laboratory means.Cr is the within-laboratory critical interval between two test results = 2.8 3 Sr.DR is the between-laboratories critical interval bet
49、ween two test results = 2.8 3SR.D6290053ANNEX(Mandatory Information)A1. RR PRODUCTS IDENTIFICATIONA1.1 Identify RR Products as follows:A1.1.1 APP RandomA1.1.2 BPP RandomA1.1.3 CPP ImpactA1.1.4 DPP ImpactA1.1.5 EPP HomopolymerA1.1.6 FLDPEA1.1.7 GEVA CopolymerA1.1.8 HHDPEAPPENDIXES(Nonmandatory Information)X1. ADDITIONAL INSTRUMENT INFORMATIONX1.1 As discussed in this test method, there are manyinstruments with different geometries being used to make themeasurements described herein. Different instruments givedifferent values
