1、Designation: D 4877 04Standard Test Method forPolyurethane Raw Materials: Determination of APHA Colorin Isocyanates1This standard is issued under the fixed designation D 4877; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the yea
2、r of last revision. A number in 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 measures the color of clear liquids. Itis applicable only to materials whose color-producing b
3、odieshave light-absorption characteristics similar to those of theplatinum cobalt color standards used.2(See Test MethodD 1209and Note 1.)1.2 The values stated in SI units are to be regarded as thestandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated wi
4、th 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. For specifichazards statements see 7.1 and Warning in 8.1.NOTE 1Although this test method and ISO 6271-1997
5、differ in somedetails, data obtained using either are technically equivalent.2. Referenced Documents2.1 ASTM Standards:3D 883 Terminology Relating to PlasticsD 1193 Specification for Reagent WaterD 1209 Test Method for Color of Clear Liquids (Platinum-Cobalt Scale)D 5386 Test Method for Color of Liq
6、uids Using TristimulusColorimetry2.2 ISO Standards:ISO 6271-1997 Clear LiquidsEstimation of Color by thePlatinum Cobalt Scale43. Terminology3.1 For definitions of terms used in this test method seeTerminology D 883.4. Summary of Test Method4.1 The color of the material to be tested is compared to as
7、eries of platinum cobalt color standards, designated by mg ofPt/mLof standard solution. The results are reported as the colorstandard, which best matches the sample (Note 2).NOTE 2Color of liquids also can be measured by visible spectroscopyand the results converted to any of several color scales. T
8、hese results canbe converted to the APHA scale by appropriate manipulations, as forexample in Test Method D 5386.5. Significance and Use5.1 This test method can be used for research or for qualitycontrol to characterize isocyanates used in polyurethane prod-ucts.5.2 For toluene diisocyanate, results
9、 from this test methodcan relate to reactivity or performance in polyurethane sys-tems.6. Apparatus6.1 Nessler Tubes, matched, 100-mL tall-form.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagent
10、s conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.5Other grades can be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy of
11、the determination.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.22 on Cellular Materials -Plastics and Elastomers.Current edition approved March 1, 2004. Published April 2004. Originallyapproved in 1988. Last previou
12、s edition approved in 1998 as D 4877 - 98.2See Standard Methods for the Examination of Water, Sewage, and IndustrialWastes, AM. Public Health Assn., 1015 15th St. NW Washington, DC 20005.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at servicea
13、stm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.5Reagent Chemicals, American Chemical Society Specifications, Ameri
14、canChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC
15、), Rockville,MD.1*A Summary of Changes 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.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent w
16、ater as definedby Type IV or better of Specification D 1193.7.3 Cobaltous Chloride Hexahydrate (CoCl26H2O).7.4 Concentrated Hydrochloric Acid (sp. gr. 1.19).7.5 Potassium Chloroplatinate (K2PtCl6).8. Sampling8.1 Since organic isocyanates react with atmospheric mois-ture, special precautions must be
17、taken in sampling (seeWarning below). Usual sampling methods (for example, sam-pling an open drum with a thief), even when carried outrapidly, can cause contamination of the sample with insolubleurea. Therefore, the sample must be blanketed with dry air ornitrogen at all times. WarningOrganic isocya
18、nates are toxicwhen they are absorbed through the skin, or when the vaporsare breathed. Adequate ventilation must be provided andprotective gloves and eyeglasses are to be worn.9. Preparation of Color Standards (See Note 3)9.1 Add 500 mL distilled water to a 1000-mL volumetricflask. Add 100 mL HCl a
19、nd mix well. Weigh to the nearest 1mg of 1.245 g of K2PtCl6and transfer it to the volumetric flask(Note 4). Add 1.0 g of crystallized CoCl26H2O. Dilute thesolution in the flask to the mark with distilled water and mixthoroughly. The color of this standard solution is equivalent to500 color units (50
20、0 mg metallic platinum/L).NOTE 3Alternatively, use a Hellige Aquatester Model 611-A orequivalent instrument having permanent sealed color standards (HelligeModel 611-10 color comparator disc of APHA cobalt-platinum colorstandards).NOTE 4If potassium chloroplatinate is not available, dissolve 0.500 g
21、of pure metallic platinum in aqua regia with heating; then remove theHNO3by repeated evaporations with fresh portions of HCl. Dissolve thisproduct together with1gofcrystallized CoCl26H2O as directed in 9.1.9.2 Prepare the required color standards by diluting the No.500 standard solution as shown in
22、Table 1. If a more exactcolor comparison is desired, prepare additional standards tosupplement those given (one color unit is equivalent to 1 mgmetallic platinum/L). When not in use, standards are to besealed to avoid evaporation and contamination.10. Procedure10.1 Fill one of two matched 100-mL tal
23、l-form Nesslertubes to the mark with the sample. Fill the second tube to themark with the standard that seems to best match the color of thesample.10.2 Compare the colors of the sample and the standard byviewing vertically down through the tubes against a whitebackground. Replace the liquid in the s
24、econd tube with lighteror darker standards until an exact match is obtained. (See Note5.)NOTE 5Rinse the second tube at least once with the replacementstandard before filling the tube to the mark with it.11. Report11.1 Report the color number of the standard that is closestin color to the sample. If
25、 the sample appears exactly halfwaybetween two standards, report the color number of the darkerstandard.12. Precision and Bias12.1 PrecisionAttempts to develop a precision and biasstatement for this test method have not been successful. Forthis reason, data on precision and bias cannot be given;howe
26、ver, the precision is expected to be equivalent to thatreported in ISO 6271-1997. Because this test method does notcontain a numerical precision and bias statement, it shall not beused as a referee test method in case of dispute. Contact theChairman, Subcommittee D20.22 (Section D20.22.01),ASTM,100
27、Barr Harbor Drive, PO Box C700, West Conshohocken,PA 19428-2959, if you are interested in participating in thedevelopment of precision and bias data for this standard.12.1.1 RepeatabilityBased on ISO 6271-1997, it wouldbe expected that two replicate test results, run on the same day,using the same e
28、quipment, by the same analyst, are to beconsidered to be different only if they differ by more than 5 %relative.12.1.2 ReproducibilityBased on ISO 6271-1997, it wouldbe expected that two test results, run on different days, usingdifferent equipment, by the different analysts, are to be con-sidered t
29、o be different only if they differ by more than 15 %relative.12.2 BiasThe bias of this test method has not yet beendetermined.13. Keywords13.1 APHA; color; isocyanates; platinum-cobalt scale poly-urethane raw materials; Pt/Co scaleTABLE 1 Color StandardsColor Standard NumberNumber 500 Standard,mLWat
30、er, mL1 0.2 99.83 0.6 99.45 1.0 99.010 2.0 98.015 3.0 97.018 3.6 96.420 4.0 96.025 5.0 95.030 6.0 94.040 8.0 92.050 10.0 90.080 12.0 88.070 14.0 86.080 16.0 84.090 18.0 82.0100 20.0 80.0120 24.0 76.0140 28.0 72.0160 32.0 68.0180 36.0 64.0200 40.0 60.0300 60.0 40.0400 80.0 20.0500 100.00 0.0D 4877 04
31、2SUMMARY OF CHANGESThis section identifies the location of selected changes to this test method. For the convenience of the user,Committee D20 has highlighted those changes that impact the use of this test method. This section also includesdescriptions of the changes or reasons for the changes, or b
32、oth.D 4877 - 04:(1) Paragraph 1.1Better defined the nature of the standardsused in the method.(2) Note 1, Section 2Updated the date of the referenced ISOstandard.(3) Paragraph 10.1Revised to create a command statementand created paragraph 10.2 for emphasis.(4) Paragraph 10.2Added a reference to Note
33、 5.(5) Note 5Added the note with additional procedural details.(6) Paragraphs 12.1.1 and 12.1.2Updated date of referencedISO standard and repeatability data from new standard.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentio
34、nedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee an
35、d must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting o
36、f theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box
37、 C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 4877 043
