1、Designation: D4877 10D4877 14Standard Test Method forPolyurethane Raw Materials: Determination of APHA Colorin Isocyanates1This standard is issued under the fixed designation D4877; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, t
2、he 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 This test method measures the color of clear liquids. It is applicable only to materials whose color-produ
3、cing bodies havelight-absorption characteristics similar to those of the platinum cobalt color standards used.2 (See Test Method D1209 and Note1.) Suitable isocyanates include toluene diisocyanate, and pure or modified monomeric methylene di(phenylisocyanate).1.2 The values stated in SI units are to
4、 be regarded as standard.1.3 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 the applicability of regulatorylimitations prior
5、 to use.NOTE 1This standard is equivalent to ISO 6271-1:2004.2. Referenced Documents2.1 ASTM Standards:3D883 Terminology Relating to PlasticsD1193 Specification for Reagent WaterD1209 Test Method for Color of Clear Liquids (Platinum-Cobalt Scale)D5386 Test Method for Color of Liquids Using Tristimul
6、us Colorimetry2.2 ISO Standards:ISO 6271-1:2004 Clear LiquidsEstimationliquidsEstimation of Colorcolour by the Platinum Cobalt Scaleplatinum-cobaltscalePart 1: Visual method43. Terminology3.1 For definitions of terms used in this test method see Terminology D883.4. Summary of Test Method4.1 The colo
7、r of the material to be tested is compared to a series of platinum cobalt color standards, designated by mg of Pt/mLof standard solution. The results are reported as the color standard, which best matches the sample (Note 2).NOTE 2Color of liquids also can be measured by visible spectroscopy and the
8、 results converted to any of several color scales. These results can beconverted to the APHA scale by appropriate manipulations, as for example in Test methods for measuring the platinum-cobalt color of liquidsinstrumentally are availablefor example, Test Method D5386.5. Significance and Use5.1 This
9、 test method can be used for research or for quality control to characterize isocyanates used in polyurethane products.5.2 For toluene diisocyanate, results from this test method can relate to reactivity or performance in polyurethane systems.1 This test method is under the jurisdiction of ASTM Comm
10、ittee D20 on Plastics and is the direct responsibility of Subcommittee D20.22 on Cellular Materials - Plasticsand Elastomers.Current edition approved Jan. 1, 2010Aug. 1, 2014. Published February 2010September 2014. Originally approved in 1988. Last previous edition approved in 20042010as D4877 - 04.
11、D4877 - 10. DOI: 10.1520/D4877-10.10.1520/D4877-14.2 See Standard Methods for the Examination of Water, Sewage, and Industrial Wastes, AM. Public Health Assn., 1015 15th St. NW Washington, DC 20005.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service a
12、t serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.4 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.This document is not an ASTM stand
13、ard 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 all cases
14、 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 States16. Apparatus6.1 N
15、essler Tubes, matched, 100-mL tall-form.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Societ
16、y where suchspecifications are available.5 Other grades can be used, provided it is first ascertained that the reagent is of sufficiently high purityto permit its use without lessening the accuracy of the determination.7.2 Purity of WaterUnless otherwise indicated, references to water shall be under
17、stood to mean reagent water as defined byType IV or better of Specification D1193.7.3 Cobaltous Chloride Hexahydrate (CoCl2 6H2O).7.4 Concentrated Hydrochloric Acid (sp. gr. 1.19).7.5 Potassium Chloroplatinate (K2PtCl6).8. Sampling8.1 Since organic isocyanates react with atmospheric moisture, take s
18、pecial precautions in sampling. Usual sampling methods,even when conducted rapidly, can cause contamination of the sample with insoluble urea. Therefore, blanket the sample with dryair or nitrogen at all times. (WarningMany diisocyanates are known or suspected sensitizers. Over-exposure to diisocyan
19、atescan lead to adverse health effects, which may include the development of occupational asthma and other respiratory, skin, and eyeeffects. Engineering controls, or personal protective equipment or both, including respiratory, skin, and eye protection, are to beused when there is a potential for o
20、ver-exposure to diisocyanates. The product suppliers MaterialSafety Data Safety Sheet(MSDS)(SDS) provides more detailed information about potential adverse health effects and other important safety and handlinginformation. Always follow the specific instructions provided on the MSDS.SDS.)9. Preparat
21、ion of Color Standards (See Note 3)9.1 Add 500 mL distilled water to a 1000-mL volumetric flask. Add 100 mL HCl and mix well. Weigh to the nearest 1 mg of1.245 g of K2PtCl6 to the nearest 1 mg and transfer it to the volumetric flask (flask. Note 4). Add 1.01.00 g of crystallizedCoCl2 6H2O. Dilute th
22、e solution in the flask to the mark with distilled water and mix thoroughly. The color of this standardsolution is equivalent to 500 color units (500 mg metallic platinum/L). platinum/L) and must fall within the limits specified in TestMethod D1209. Alternatively, it is acceptable to use commerciall
23、y available 500 platinum-cobalt stock solutions that meet thespecifications of Test Method D1209.NOTE 3Alternatively, use a Hellige Aquatester Model 611-A or equivalent instrument Color comparators having permanent sealed color standards(Hellige Model 611-10 color comparator disc of APHA cobalt-plat
24、inum color standards). platinum-cobalt color standards are permissible provided it isfirst determined that the accuracy and precision of the measurements are not reduced.NOTE 4If potassium chloroplatinate is not available, dissolve 0.500 g of pure metallic platinum in aqua regia with heating; then r
25、emove the HNO3by repeated evaporations with fresh portions of HCl. Dissolve this product together with 1 g of crystallized CoCl2 6H2O as directed in 9.1.9.2 Prepare the required color standards by diluting the No. 500 standard solution as shown in Table 1. If a more exact colorcomparison is desired,
26、 prepare additional standards to supplement those given (one color unit is equivalent to 1 mg metallicplatinum/L). When not in use, standards are to be sealed to avoid evaporation and contamination.10. Procedure10.1 Fill one of twoa matched set of 100-mL tall-form Nessler tubes to the mark with the
27、sample. Fill thea second tube fromthe matched set to the mark with the standard that seems to best match the color of the sample.10.2 Compare the colors of the sample and the standard by viewing vertically down through the tubes against a whitebackground. Replace the liquid in the second tubeFill ad
28、ditional tubes from the matched set with lighter or darker standards untilan exact match is obtained. (See Note 54.)NOTE 4Rinse the second tube at least once with the replacement standard before filling the tube to the mark with it.When properly sealed and stored,standards can be kept in the Nessler
29、 tubes between use.11. Report11.1 Report the color number of the standard that is closest in color to the sample. If the sample appears exactly halfwaybetween two standards, report the color number of the darker standard.5 Reagent Chemicals, American Chemical Society Specifications, American Chemica
30、l Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockvi
31、lle, MD.D4877 14212. Precision and Bias12.1 PrecisionAttempts to develop a precision and bias statement for this test method have not been successful. For thisreason, data on precision and bias cannot be given; however, the precision is expected to be equivalent to that reported inISO 6271-1:2004. B
32、ecause this test method does not contain a numerical precision and bias statement, it shall not be used as areferee test method in case of dispute. Contact the Chairman, Subcommittee D20.22 (Section D20.22.01),ASTM, 100 Barr HarborDrive, PO Box C700, West Conshohocken, PA 19428-2959, if you are inte
33、rested in participating in the development of precisionand bias data for this standard.12.1.1 RepeatabilityBased on ISO 6271-1:2004, it would be expected that two replicate test results, each the mean ofduplicates, run on the same day, using the same equipment, by the same analyst, are to be conside
34、red to be different only if theydiffer by more than 5 % relative.12.1.2 ReproducibilityBased on ISO 6271-1:2004, it would be expected that two test results, run on different days, each themean of duplicates, using different equipment, by the different analysts, are to be considered to be different o
35、nly if they differ bymore than 15 % relative.12.2 BiasThe bias of this test method has not yet been determined.13. Keywords13.1 APHA; color; isocyanates; platinum-cobalt scale polyurethane raw materials; Pt/Co scaleSUMMARY OF CHANGESCommittee D20 has identified the location of selected changes to th
36、is standard since the last issue(D4877 - 04)(D4877 - 10) that may impact the use of this standard. (JanuaryAugust 1, 2010)2014)(1) Added examples of suitable isocyanates in 1.1.(2) Editorial changes to be consistent with ISO spelling and format.(3) Editorial changes made for clarity in Note 2.(4) Re
37、vised Added an additional decimal place for the weight of CoCl2.6H2O in 1.39.1,. 8.1,Added 12.1.1, andthe requirement12.1.2that the 500 platinum-cobalt stock solution must conform to Test Method D1209. Added that commercially available 500platinum-cobalt stock solutions are acceptable(5) Removed ven
38、dor specific language and added requirements for the use of a color comparator in Note 3(6) Modified the procedure in Section 10 and Note 4to allow the use of matched sets of Nessler tubes versus only matched pairsand to allow standards to be kept in Nessler tubes between useTABLE 1 Color StandardsC
39、olor Standard Number Number 500 Standard, mL Water, 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 60.03
40、00 60.0 40.0400 80.0 20.0500 100.00 0.0D4877 143ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights,
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