1、Designation: D 4659 03Standard Test Methods forPolyurethane Raw Materials: Determination of SpecificGravity of Isocyanates1This standard is issued under the fixed designation D 4659; 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 These test methods determine the specific gravity oftoluenediiosocyanate and crude methylene-bis-(4-phen
3、ylisocyanate). These test methods also are applicable tomany other liquids. (See Note 1.)1.1.1 Test Method ASpecific gravity by pycnometer, forhigh-accuracy determination.1.1.2 Test Method BSpecific gravity by hydrometer, for aless accurate, but rapid, determination.1.2 The values stated in SI units
4、 are to be regarded as thestandard. The values given in brackets are for information only.1.3 This standard does 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 practic
5、es and determine the applica-bility of regulatory limitations prior to use. For specificwarning and precautionary statements see Notes 2 and 3.NOTE 1There is no equivalent ISO standard.2. Referenced Documents2.1 ASTM Standards:2D 883 Terminology Relating to PlasticsD 891 Test Methods for Specific Gr
6、avity, Apparent, ofLiquid Industrial ChemicalsD 1193 Specification for Reagent WaterE 1 Specification for ASTM ThermometersE 100 Specification for ASTM HydrometersE 202 Test Methods for Analysis of Ethylene Glycols andPropylene Glycols3. Terminology3.1 Definitions:3.1.1 For definitions of terms used
7、 in these test methods seeTerminology D 883.3.2 Description of Term Specific to This Standard:3.2.1 specific gravitythe ratio of the weight in air of agiven volume of the material at a stated temperature to theweight in air of an equal volume of water at a statedtemperature. It shall be expressed as
8、 specific gravity, 25/25C,indicating that the sample and reference water were bothmeasured at 25C.4. Significance and Use4.1 These test methods can be used for research or forquality control to characterize isocyanates used in polyurethaneproducts.TEST METHOD ASPECIFIC GRAVITY BYPYCNOMETER5. Apparat
9、us5.1 Pycnometer, of 25 or 50-mL capacity, conical shape witha capillary side arm overflow tube having a standard-taper 5/12ground-glass joint and a ground-glass vented cap. A thermom-eter graduated from 12 to 38C in 0.2 divisions attached to theneck of the flask by a standard-taper 10/18 ground-gla
10、ss joint.This thermometer should be calibrated using the ASTMthermometer specified in 5.3.5.2 Water BathA water bath maintained at 25 6 0.05C.5.3 ThermometerAn ASTM low-softening point ther-mometer, calibrated from 2 to +80C, which meets therequirements for Thermometer 15C in Specification E 1.5.4 A
11、nalytical BalanceA balance having a sensitivity of atleast 0.1 mg.6. Reagents and Materials6.1 Purity of ReagentsUse reagent grade chemicals in alltests. Unless otherwise indicated, it is intended that all reagentsconform to the specifications of the Committee on Analytical1These test methods are un
12、der the jurisdiction of ASTM Committee D20 onPlastics and are the direct responsibility of Subcommittee D20.22 on CellularPlastics.Current edition approved November 1, 2003. Published January 2004. Originallyapproved in 1987. Last previous edition approved in 1998 as D 4659 - 98.2For referenced ASTM
13、 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 standard.Copyright ASTM
14、 International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Reagents of the American Chemical Society where suchspecifications are available.3Other grades may be used, pro-vided it is ascertained that the reagent is of sufficiently highpurity to permit its use
15、 without lessening the accuracy of thedetermination.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as definedby Type IV or better of Specification D 1193.6.3 Chromic Acid Cleaning SolutionPrepare a saturatedsolution of chromic acid (CrO3)
16、in concentrated sulfuric acid(H2SO4, sp gr 1.84).7. Sampling7.1 Since organic isocyanates react with atmospheric mois-ture, take special precautions in sampling WarningOrganicisocyanates are toxic when they are absorbed through the skin,or when the vapors are breathed. PrecautionProvide ad-equate ve
17、ntilation and wear protective gloves and eyeglassesUsual sampling methods (for example, sampling an open drumwith a thief), even when carried out rapidly, can causecontamination of the sample with insoluble urea. Therefore,blanket the sample with dry air or nitrogen at all times.8. Test Conditions8.
18、1 Since isocyanates react with moisture, keep laboratoryhumidity low, preferably around 50 % relative humidity.9. Procedure9.1 Clean the pycnometer by filling it with chromic acidcleaning solution and by allowing it to stand for a few hours.Empty the pycnometer and rinse well with distilled water.9.
19、2 Fill the pycnometer with freshly boiled distilled waterthat has been cooled to 22 to 24C. Insert the thermometer intothe pycnometer without trapping air bubbles. Place the pyc-nometer in a water bath at 25 6 0.05C and allow it and itscontents to equilibrate for at least 30 min. Wipe the overflowfr
20、om the side-arm capillary and cover it with the vented cap.Remove the pycnometer from the bath, wipe dry, and weigh.9.3 Empty the pycnometer and rinse it with alcohol, thenwith ether. Remove the ether and dry the pycnometer undervacuum for 15 min. Weigh the pycnometer. Determine theweight, W, of the
21、 water at 25.0C in air by subtracting theweight of the empty pycnometer from the weight of thepycnometer filled with water.NOTE 2Other drying techniques may be used if ether is to be avoided.It must be established that for any alternative drying method, a clean anddry pycnometer results.9.4 Carry ou
22、t the rest of the procedure in a ventilated hood.The sample for testing must be completely liquid. If the samplecontains solid toluene diisocyanate, warm it in its originalcontainer until it becomes liquid. Rapidly cool the liquid to 22to 24C and fill the pycnometer, while minimizing exposure ofthe
23、sample to air.9.5 Insert the thermometer into the pycnometer withouttrapping air bubbles. Cover the side arm with the vented capand allow the pycnometer to equilibrate in the water bath for atleast 30 min. Wipe the overflow from the side arm capillaryand cover it with the cap vented. Remove the pycn
24、ometer fromthe bath, wipe dry, and weigh. To obtain the weight, S, of thesample at 25.0C, subtract the weight of the empty pycnometerfrom the weight when filled with sample.10. Calculation10.1 Calculate the specific gravity at 25/25C as follows:Specific gravity, 25/25C 5SWwhere:S = sample used, g (s
25、ee 9.5), andW = water in the pycnometer, g (see 9.3).11. Precision and Bias11.1 Attempts to develop a precision and bias statement forthis test method have not been successful. Data on precisionand bias cannot be given for this reason. Anyone wishing toparticipate in the development of precision and
26、 bias datashould contact the Chairman, Subcommittee D20.22 (SectionD20.22.01), ASTM, 100 Barr Harbor Drive, West Consho-hocken, PA 19428-2959.11.2 Test Method E 202 is similar and does include preci-sion data. Precision statements from E 202 are restated belowas an estimate of the precision for this
27、 test method.11.2.1 RepeatabilityIt has been estimated that duplicateresults by the same analyst should be considered suspect if theydiffer by 0.0002 units.11.2.2 ReproducibilityIt has been estimated that resultsreported by different laboratories should be considered suspectif they differ by 0.0008
28、units.11.3 BiasThere are no recognized standards by which toestimate the bias of this test method.TEST METHOD BSPECIFIC GRAVITY BYHYDROMETER12. Apparatus12.1 HydrometerAn ASTM hydrometer with a specificgravity range from 1.195 to 1.255 at 15.6/15.6C conformingto the requirements for Hydrometer 115H
29、in SpecificationE 100.12.2 Hydrometer CylinderA clear glass cylinder with aninside diameter at least 25.4 mm 1 in. larger than thehydrometer and tall enough so that there is at least 1 in.between the bottom of the cylinder and the bottom of thehydrometer after equilibration at 25C.12.3 ThermometerSe
30、e 5.3.12.4 Water BathSee 5.2.13. Procedure (See Warning statement below.)13.1 The sample for test must be completely liquid. If thesample is turbid, warm it in its original container until it3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For s
31、uggestions 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. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.D 4659 032becomes clear,
32、then cool it to 22 to 24C.WarningCarry outthis entire procedure in a well-ventilated hood.13.2 To avoid forming air bubbles, slowly pour the sampleinto the dry hydrometer cylinder. Remove any air bubblesadhering to the surface by touching them with a piece of cleanfilter paper. Place the cylinder in
33、 the water bath. Stir thecontents of the cylinder, being careful to avoid formation of airbubbles. When the temperature of the sample is 24.8C, slowlyand carefully lower the hydrometer into the sample liquid to alevel two small scale divisions below that at which it will floatand then release the hy
34、drometer. Allow the hydrometer to cometo rest and make sure it does not touch the walls of the cylinder.When the temperature of the sample reaches 25.0C, read thegravity by sighting below the level of the liquid and slowlyraising up until the surface of the sample, first seen as adistorted ellipse,
35、seems to become a straight line cutting thehydrometer scale.13.3 Determine the temperature of the sample just beforeand just after reading the hydrometer.14. Calculation14.1 Calculate the specific gravity at 25/25C as follows(Note 3):Specific gravity, 25/25C 5 observed value10.0021NOTE 3The correcti
36、on factor +0.0021 is applied to correct the readingto 25/25C because the hydrometer was standardized at 15.6/15.6C.15. Precision and Bias15.1 Attempts to develop a precision and bias statement forthis test method have not been successful. Data on precisionand bias cannot be given for this reason. An
37、yone wishing toparticipate in the development of precision and bias datashould contact the Chairman, Subcommittee D20.22 (SectionD20.22.01), ASTM, 100 Barr Harbor Drive, West Consho-hocken, PA 19428-2959.15.2 Test Method D 891 is similar and does include preci-sion data. Precision statements from D
38、891 are restated belowas an estimate of the precision for this test method.15.2.1 RepeatabilityIt has been estimated that duplicateresults by the same analyst should be considered suspect if theydiffer by 0.0005 units.15.2.2 ReproducibilityIt has been estimated that resultsreported by different labo
39、ratories should be considered suspectif they differ by 0.0021 units.15.3 There are no recognized standards by which to esti-mate the bias of this test method.16. Keywords16.1 density; hydrometer; isocyanates; polyurethane rawmaterials; pycnometer; specific gravitySUMMARY OF CHANGESThis section ident
40、ifies the location of selected changes to these test methods. For the convenience of the user,Committee D20 has highlighted those changes that may impact the use of these test methods. This section mayalso include descriptions of the changes or reasons for the changes, or both.D 4659 03:(1) Added No
41、te 2.D 4659 98:(1) Section 1.1Modified the scope to include both toluene-diisocyanate and methylene-bis-(4-phenylisocyanate).(2) Section 2.1Added references to Test Methods D 891 andE 202.(3) FootnotesInserted footnote 5 and renumbered subsequentfootnote.(4) Section 6.2Changed the requirement from “
42、Type I” to“Type IV or better” water.(5) Section 11Replaced the precision and bias statement withquote and reference to the precision and bias statement of TestMethods E 202.(6) Section 15Replaced the precision and bias statement withquote and reference to the precision and bias statement of TestMeth
43、ods D 891.ASTM 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, and the riskof infringement of such r
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46、TM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box 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 4659 033
