1、Designation: D4659 14Standard Test Methods forPolyurethane Raw Materials: Determination of SpecificGravity of Isocyanates1This standard is issued under the fixed designation D4659; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e 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 determine the specific gravity oftoluenediisocyanate and crude methylene-bis-(4-phenylis
3、ocyanate). 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 are
4、 to be regarded asstandard. No other units of measurement are included in thisstandard.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 practices
5、and determine the applica-bility of regulatory limitations prior to use. For specificwarning and precautionary statements see Section 7.NOTE 1There is no known ISO equivalent to this standard.2. Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD891 Test Methods for Specif
6、ic Gravity,Apparent, of LiquidIndustrial ChemicalsD1193 Specification for Reagent WaterD4052 Test Method for Density, Relative Density, and APIGravity of Liquids by Digital Density MeterE100 Specification for ASTM HydrometersE202 Test Methods for Analysis of Ethylene Glycols andPropylene GlycolsE225
7、1 Specification for Liquid-in-Glass ASTM Thermom-eters with Low-Hazard Precision Liquids3. Terminology3.1 DefinitionsFor definitions of terms used in these testmethods see Terminology D883.3.2 Definitions of Terms Specific to This Standard:3.2.1 specific gravitythe ratio of the weight in air of agiv
8、en 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 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 use
9、d for research or forquality control to characterize isocyanates used in polyurethaneproducts.4.2 Ageneral test method for specific gravity using a digitaldensity meter, which applies to isocyanates as well as otherliquids is published in Test Method D4052.TEST METHOD ASPECIFIC GRAVITY BYPYCNOMETER5
10、. Apparatus5.1 Pycnometer, of 25 or 50-mLcapacity, 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 gr
11、ound-glass joint.This thermometer is to be calibrated using the ASTM ther-mometer specified in 5.3.5.2 Water BathA water bath maintained at 25 6 0.05C.5.3 ThermometerAn ASTM low-softening pointthermometer, calibrated from 2 to +80C, which meets therequirements for Thermometer S15C in Specification E
12、2251.5.4 Analytical BalanceAbalance having a sensitivity of atleast 0.1 mg.1These test methods are under the jurisdiction of ASTM Committee D20 onPlastics and are the direct responsibility of Subcommittee D20.22 on CellularMaterials - Plastics and Elastomers.Current edition approved March 1, 2014. P
13、ublished March 2014. Originallyapproved in 1987. Last previous edition approved in 2009 as D4659 - 09. DOI:10.1520/D4659-14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, r
14、efer to the standards Document Summary page onthe ASTM website.*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. Reagents and Materials6.1 Purity of ReagentsUse reagent
15、 grade chemicals in alltests. Unless otherwise indicated, it is intended that all reagentsconform to the specifications of the Committee on AnalyticalReagents of the American Chemical Society where suchspecifications are available.3Other grades can be used, pro-vided it is ascertained that the reage
16、nt is of sufficiently highpurity to permit its use 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 D1193.6.3 Chromic Acid Cleaning SolutionPr
17、epare a saturatedsolution of chromic acid (CrO3) in concentrated sulfuric acid(H2SO4, sp gr 1.84).7. Sampling7.1 Since organic isocyanates react with atmosphericmoisture, take special precautions in sampling. Usual samplingmethods, even when conducted rapidly, can cause contamina-tion of the sample
18、with insoluble urea. Therefore, blanket thesample with dry air or nitrogen at all times. (WarningManydiisocyanates are known or suspected sensitizers. Over-exposure to diisocyanates can lead to adverse health effects,which may include the development of occupational asthmaand other respiratory, skin
19、, and eye effects. Engineeringcontrols, or personal protective equipment, or both, includingrespiratory, skin, and eye protection, are to be used when thereis a potential for over-exposure to diisocyanates. The productsuppliers Material Safety Data Sheet (MSDS) provides moredetailed information abou
20、t potential adverse health effects andother important safety and handling information. Alwaysfollow the specific instructions provided on the MSDS.)8. Test Conditions8.1 Since isocyanates react with moisture, keep laboratoryhumidity low, preferably around 50 % relative humidity.9. Procedure9.1 Clean
21、 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.9.2 Fill the pycnometer with freshly boiled distilled waterthat has been cooled to 22 to 24C. Insert the thermometer intothe pycnomete
22、r 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 overflowfrom 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 py
23、cnometer 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 water at 25.0C in air by subtracting theweight of the empty pycnometer from the weight of thepycnometer filled with water.NOTE 2Oth
24、er drying techniques can 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 out the rest of the procedure in a ventilated hood.The sample for testing must be completely liquid. If the samplecontains solid tolue
25、ne 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 sample to air.9.5 Insert the thermometer into the pycnometer withouttrapping air bubbles. Cover the side arm with the vented capand
26、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 pycnometer fromthe bath, wipe dry, and weigh. To obtain the weight, S, of thesample at 25.0C, subtract the weight of the empty pycnomete
27、rfrom 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 (see 9.5), andW = water in the pycnometer, g (see 9.3).11. Precision and Bias11.1 Attempts to develop a precision and bias statement f
28、orthis 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 bias data cancontact the Chairman, Subcommittee D20.22 (SectionD20.22.01), ASTM, 100 Barr Harbor Drive, WestConshohocken, PA 19428-
29、2959.11.2 Test Method E202 is similar and does include precisiondata. Precision statements from E202 are restated below as anestimate of the precision for this test method.11.2.1 RepeatabilityIt has been estimated that duplicateresults by the same analyst are to be considered suspect if theydiffer b
30、y 0.0002 units.11.2.2 ReproducibilityIt has been estimated that resultsreported by different laboratories are to be considered suspectif they differ by 0.0008 units.11.3 BiasThere are no recognized standards by which toestimate the bias of this test method.3Reagent Chemicals, American Chemical Socie
31、ty 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, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutic
32、al Convention, Inc. (USPC), Rockville,MD.D4659 142TEST 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 in SpecificationE100.12.2 Hydrometer CylinderA c
33、lear 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 ThermometerSee 5.3.12.4 Water BathSee 5.2.13. Sampling13.1 Sin
34、ce organic isocyanates react with atmosphericmoisture, take special precautions in sampling. Usual samplingmethods, even when conducted rapidly, can cause contamina-tion of the sample with insoluble urea. Therefore, blanket thesample with dry air or nitrogen at all times. (WarningManydiisocyanates a
35、re known or suspected sensitizers. Over-exposure to diisocyanates can lead to adverse health effects,which may include the development of occupational asthmaand other respiratory, skin, and eye effects. Engineeringcontrols, or personal protective equipment, or both, includingrespiratory, skin, and e
36、ye protection, are to be used when thereis a potential for over-exposure to diisocyanates. The productsuppliers Material Safety Data Sheet (MSDS) provides moredetailed information about potential adverse health effects andother important safety and handling information. Alwaysfollow the specific ins
37、tructions provided on the MSDS.)14. Test Conditions14.1 Since isocyanates react with moisture, keep laboratoryhumidity low, preferably around 50 % relative humidity15. Procedure15.1 The sample for test must be completely liquid. If thesample is turbid, warm it in its original container until itbecom
38、es clear, then cool it to 22 to 24C. Carry out this entireprocedure in a well-ventilated hood.15.2 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 cylinde
39、r in 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 th
40、e hydrometer.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 ellips
41、e, seems to become a straight line cutting thehydrometer scale.15.3 Determine the temperature of the sample just beforeand just after reading the hydrometer.16. Calculation16.1 Calculate the specific gravity at 25/25C as follows(Note 3):Specific gravity, 25/25C 5 observed value10.0021NOTE 3The corre
42、ction factor +0.0021 is applied to correct the readingto 25/25C because the hydrometer was standardized at 15.6/15.6C.17. Precision and Bias17.1 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.
43、 Anyone wishing toparticipate in the development of precision and bias data cancontact the Chairman, Subcommittee D20.22 (SectionD20.22.01), ASTM, 100 Barr Harbor Drive, WestConshohocken, PA 19428-2959.17.2 Test Method D891 is similar and does include preci-sion data. Precision statements from D891
44、are restated belowas an estimate of the precision for this test method.17.2.1 RepeatabilityIt has been estimated that duplicateresults by the same analyst are to be considered suspect if theydiffer by 0.0005 units.17.2.2 ReproducibilityIt has been estimated that resultsreported by different laborato
45、ries are to be considered suspectif they differ by 0.0021 units.17.3 There are no recognized standards by which to esti-mate the bias of this test method.18. Keywords18.1 density; hydrometer; isocyanates; polyurethane rawmaterials; pycnometer; specific gravityD4659 143SUMMARY OF CHANGESCommittee D20
46、 has identified the location of selected changes to this standard since the last issue (D4659 - 09)that may impact the use of this standard. (March 1, 2014)(1) Added Test Method D4052 under 2.1.(2) Added 4.2 indicating the existence of Test Method D4052.(3) Updated method for use of non-mercury ther
47、mometers in5.3.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 s
48、uch rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and 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 add
49、itional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of 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 C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple c
