1、Designation: D4890 18Standard Test Methods forPolyurethane Raw Materials: Determination of Gardner andAPHA Color of Polyols1This standard is issued under the fixed designation D4890; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 These test methods measure visually the color of clearpolyester and polyether liquids. They apply only to
3、 materialswhose colors have light-absorption characteristics similar tothose of the standards. An alternative method is Test MethodD1209 (see Note 1).1.2 UnitsThe values stated in SI units are to be regardedas standard. No other units of measurement are included in thisstandard.1.3 This standard doe
4、s not purport to address all of thesafety 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 1Test Method A of this standard
5、 is equivalent to ISO 6271-1.Test Method B of this standard is equivalent to ISO 4630-1.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,
6、 Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD1193 Specification for Reagent WaterD1209 Test Method for Color of Clear Liquids (Platinum-Cobalt Scale)D538
7、6 Test Method for Color of Liquids Using TristimulusColorimetryD6166 Test Method for Color of Pine Chemicals and Re-lated Products (Instrumental Determination of GardnerColor)E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE308 Practice for Computing the Colors of Objects by
8、 Usingthe CIE SystemE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1164 Practice for Obtaining Spectrometric Data for Object-Color Evaluation2.2 ISO Standards:3ISO 4630-1 Clear LiquidsEstimation of Colour by theGardner Colour ScalePart 1: Visual Meth
9、odISO 4630-2 Clear LiquidsEstimation of Colour by theGardner Colour ScalePart 2: Spectroscopic MethodISO 6271-1 Clear LiquidsEstimation of Colour by thePlatinum-Cobalt ScalePart 1: Visual MethodISO 6271-2 Clear LiquidsEstimation of Colour by thePlatinum-Cobalt ScalePart 2: Spectroscopic Method3. Ter
10、minology3.1 For definitions of terms used in these test methods seeTerminology D883.4. Summary of Test Method4.1 In Test Method A, the color of the material to be testedis compared to a series of color standards with definedchromaticity coordinates, prepared in one of three ways. Theresults are repo
11、rted as the color standard, which best matchesthe sample.4.2 In Test Method B, the color of the material to be testedis compared to a series of platinum-cobalt color standards,designated by mg of Pt/mLof standard solution. The results arereported as the color standard, which best matches the sample(
12、see Note 2).NOTE 2Color of liquids are also measured by visible spectroscopyand the results converted to any of several color scales. These results areconverted to theAPHAscale by appropriate manipulations, as for example1These test methods are under the jurisdiction of Committee D20 on Plastics and
13、are the direct responsibility of Subcommittee D20.22 on Cellular Materials - Plasticsand Elastomers.Current edition approved Aug. 1, 2018. Published August 2018. Originallyapproved in 1988. Last previous edition approved in 2013 as D4890 - 13. DOI:10.1520/D4890-18.2For referenced ASTM standards, vis
14、it 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.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York
15、, NY 10036, http:/www.ansi.org.*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 StatesThis international standard was developed in accordance with internationally recognized pri
16、nciples on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1in Test Method D5386 and ISO 6271-2. These results are converted to theGa
17、rdner scale by appropriate manipulations, as for example in TestMethod ISO 4630-2.5. Significance and Use5.1 These test methods are suitable for quality control, asspecification tests, and for research. Color is an importantproperty of urethane products.6. Sampling6.1 Polyesters and polyethers usual
18、ly contain moleculescovering an appreciable range of molecular weights. Thesehave a tendency to fractionate during solidification. Unless thematerial is a liquid or finely ground solid it is necessary to melt(using no higher temperature than necessary) and mix the resinwell before removing a sample
19、for analysis. Many polyols arehygroscopic and care must be taken to provide minimumexposure to atmospheric moisture during the sampling.7. Purity of Reagents7.1 Purity of ReagentsReagent-grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conf
20、orm to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.4Other grades areacceptable, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without reducing theaccuracy of t
21、he determination.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as definedby Type IV or better of Specification D1193.TEST METHOD AGARDNER COLOR8. Apparatus8.1 Gardner-Holdt Tubes, of clear glass, with closed, flat,even bottoms, and having
22、 the following approximate dimen-sions and markings:8.1.1 A uniform internal length of 112 mm,8.1.2 A uniform internal diameter throughout the length ofthe tube of 10.75 mm, and8.1.3 An etched line around the outside of the tube 5 mmfrom the open end and a second etched line around the outsideof the
23、 tube 13 mm from the open end.9. Reagents9.1 Cobalt Chloride SolutionPrepare a solution contain-ing 1 part by weight of cobalt chloride (CoCl26H2O) to 3parts of HCl (1 to 17).9.2 Ferric Chloride SolutionPrepare a solution containingapproximately 5 parts by weight of ferric chloride(FeCl36H2O) and 1.
24、2 parts of HCl (1 to 17). Adjust to exactcolor equivalence to a freshly prepared solution containing 3 gof K2Cr2O7in 100 mL of H2SO4(sp gr 1.84).9.3 Hydrochloric Acid (1 to 17)Mix 1 volume of concen-trated hydrochloric acid (HCl, sp gr 1.19) with 17 volumes ofwater.9.4 Hydrochloric Acid (0.1 N)Prepa
25、re 0.1 N HCl.9.5 Potassium Chloroplatinate (PtCl6).9.6 Potassium Dichromate (K2Cr2O7).9.7 Sulfuric Acid (sp gr 1.84)Concentrated sulfuric acid(H2SO4).10. Gardner Color Reference Standards510.1 The primary standards for color shall consist of solu-tions defined by their spectral transmittance in 1-cm
26、 cell withparallel sides. The chromaticity coordinates of these solutionsshall conform to those given in Table 1 when determined on a1-cm layer of the solution in accordance with Practice E1164and Test Methods E308 and D6166.10.2 For comparison, permanent solutions of known colorare more satisfactor
27、y. The approximate composition of solu-tions giving each of the 18 Gardner colors is also given inTable 1. The solutions shall be made from K2PtCl6in 0.1 NHCl, or, in the darker colors, from stock solutions of FeCl3,CoCl2, and HCl (see 9.1, 9.2, and 9.3). Pre-prepared Gardnercolor standard solutions
28、 are commonly available for purchase.10.3 If the solutions in 10.2 are unavailable, solutions ofK2Cr2O7(sp gr 1.84) are used as reference standards. Theapproximate composition of these standards is also given inTable 1. Each solution must be freshly made for the colorcomparison, using gentle heat, i
29、f necessary, to effect solution.10.4 Secondary reference standards are available in theform of 18 colored glass disks, which are set into a pair oflarger, plastic disks and the latter mounted to rotate in ahousing for holding the sample tube and glass disk in close andfixed proximity.11. Procedure11
30、.1 Fill the tube with sample, free of solid particles or airbubbles, so that the apparent upper edge of the liquid meniscusis even with the lower etched line on the tube.11.2 Determine the color by comparison with the referencestandard solutions prescribed in Table 1, by comparing thesample and the
31、standard in Gardner-Holdt viscosity tubes asdescribed. Make the comparison at 25 6 5C by placing tubesclose together and looking through them against a whitebackground or by comparison to the standards in a color disk.12. Report12.1 Report the color of the sample in terms of the Gardnerstandard numb
32、er that is nearest to it in color. If the sample4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole
33、, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.5The sole source of supply of the glass color standards and color standardsolutions known to the committee at this time is BYK-Gardner USA, 9104 GuilfordRoad, Columbia,
34、MD 21046. If you are aware of alternative suppliers, pleaseprovide this information to ASTM International Headquarters. Your comments willreceive careful consideration at a meeting of the responsible technical committee,1which you may attend.D4890 182appears exactly halfway between two standards, re
35、port thecolor number of the darker standard.13. Precision and Bias613.1 Table 2 is based on an interlaboratory study conductedin 2011. Six laboratories tested two different polyurethanematerials. Every “test result” represents an individual determi-nation. Each laboratory reported three replicate te
36、st results foreach material. Practice E691 was followed for the design andanalysis of the data; the details are given in ASTM ResearchReport No. D20-1257.13.2 CautionThe explanation of the repeatability (r) andreproducibility (R) is only intended to present a meaningfulway of considering the approxi
37、mate precision of this testmethod. Do not apply the data in Table 2 to acceptance orrejection of materials, as these data apply only to the materialstested in the round robin and are unlikely to be rigorouslyrepresentative of other lots, formulations, conditions, materials,or laboratories. Users of
38、this test method need to apply theprinciples outlined in Practice E691 to generate data specific totheir materials and laboratory (or between specific laborato-ries). The principles would then be valid for such data13.3 RepeatabilityPrecision under repeatability condi-tions.13.4 ReproducibilityPreci
39、sion under reproducibility con-ditions.13.5 Repeatability Limit, rThe value below which theabsolute difference between two individual test results obtainedunder repeatability conditions is expected to occur with aprobability of approximately 0.95 (95 %). For the data gener-ated in Table 2, the maxim
40、um expected difference between twotest results for the same material, obtained by the sameoperator using the same equipment on the same day in the samelaboratory due solely to the method is 0.7 units.13.6 Reproducibility Limit, RThe value below which theabsolute difference between two individual tes
41、t results obtainedunder reproducibility conditions is expected to occur with aprobability of approximately 0.95 (95 %). For the data gener-ated in Table 2, the maximum expected differences betweentwo test results for the same material, obtained by differentoperators using different equipment in diff
42、erent laboratoriesdue solely to the method is 2.0 units.13.7 Any judgment in accordance with the repeatability andreproducibility statements shown above would have an ap-proximate 95 % (0.95) probability of being correct.13.8 BiasThere are no recognized standards by which toestimate bias of this met
43、hod.TEST METHOD BAPHA COLOR14. Apparatus14.1 Nessler Tubes, matched 100-mL, tall-form.15. Reagents15.1 Hydrochloric Acid (sp gr 1.19)Concentrated hydro-chloric acid (HCl).15.2 Potassium Chloroplatinate (K2PtCl6).15.3 Cobaltous Chloride Hexahydrate (CoCl26H2O).16. Preparation of Color Standards16.1 P
44、re-prepared platinum-cobalt standards are commonlyavailable for purchase or prepared by the following. Measure500 mLof water into a 1000-mLvolumetric flask.Add 100 mLof the HCl and mix well. Weigh 1.245 g of K2PtCl6to thenearest 1 mg and transfer to the flask (see Note 3). Add 1.0 gof crystallized C
45、oCl26H2O. Dilute the solution in the flask to6Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D20-1257. ContactASTM CustomerService at serviceastm.org.TABLE 1 Gardner Reference Standard Color SolutionsGardner Color StandardNumber
46、Chromaticity CoordinatesAPotassiumChloroplatinate,g/1000 mL of 0.1N HClIron-Cobalt SolutionsPotassiumDichromate, g/100 mLSulfuric AcidBYxyFerric ChlorideSolution, mLCobalt ChlorideSolution, mLHydrochloric Acid, mL1 80 0.3177 0.3303 0.550 . . . . . . . . . 0.00392 79 0.3233 0.3352 0.865 . . . . . . .
47、 . . 0.00483 76 0.3329 0.3452 1.330 . . . . . . . . . 0.00714 75 0.3437 0.3644 2.080 . . . . . . . . . 0.01125 74 0.3558 0.3840 3.035 . . . . . . . . . 0.02056 71 0.3767 0.4061 4.225 . . . . . . . . . 0.03227 67 0.4044 0.4352 6.400 . . . . . . . . . 0.03848 64 0.4207 0.4498 7.900 . . . . . . . . . 0
48、.05159 61 0.4343 0.4640 . . . 3.8 3.0 93.2 0.078010 57 0.4503 0.4760 . . . 5.1 3.6 91.3 0.16411 45 0.4842 0.4818 . . . 7.5 5.3 87.2 0.25012 36 0.5077 0.4638 . . . 10.8 7.6 81.6 0.38013 30 0.5392 0.4458 . . . 16.6 10.0 73.4 0.57214 22 0.5646 0.4270 . . . 22.2 13.3 64.5 0.76315 16 0.5857 0.4089 . . .
49、29.4 17.6 53.0 1.04116 11 0.6047 0.3921 . . . 37.8 22.8 39.4 1.28017 6 0.6290 0.3701 . . . 51.3 25.6 23.1 2.22018 4 0.6477 0.3521 . . . 100.0 0.0 0.0 3.00AChromaticity coordinates for CIE standard illuminant C and the CIE 1931 (2) standard observer.BThe dichromate color standards have been found to be less reliable than chloroplatinate or iron-cobalt color standards. They are included in Table 1 for reference only.D4890 183the mark with water and mix thoroughly. The color of thisstandard solution is equivalent to 500 units (500 mg metallicplatinum/
