1、Designation: D 4878 08Standard Test Methods forPolyurethane Raw Materials: Determination of Viscosity ofPolyols1This standard is issued under the fixed designation D 4878; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、 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. Scope1.1 These test methods (A and B) determine the viscosity ofpolyols in the range from 10 to 100 000 mPas(cP) at 25C orat 5
3、0C. Test Method A also applies to more viscous samplesthat are soluble in n-butyl acetate. Test Method B is simply areference to a general procedure for kinematic viscosity,D 445. (See Note 1.)1.2 The values stated in SI units are to be regarded as thestandard. Other equivalent units are provided be
4、cause ofcurrent common usage.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 and determine the applica-bility of regulatory limitations
5、 prior to use.NOTE 1There is no equivalent ISO standard for Test Method Aalthough ISO 3219 is similar. Test Method B is equivalent to ISO 3104.2. Referenced Documents2.1 ASTM Standards:2D 445 Test Method for Kinematic Viscosity of Transparentand Opaque Liquids (and Calculation of Dynamic Viscos-ity)
6、D 883 Terminology Relating to PlasticsE1 Specification for ASTM Liquid-in-Glass Thermometers2.2 ISO Standards:3ISO 3104ISO 32193. Terminology3.1 For definitions of terms used in these test methods seeTerminology D 883.4. Significance and Use4.1 These test methods are suitable for research or as qual
7、itycontrol or specification tests.4.2 Viscosity measures the resistance of a fluid to uniformlycontinuous flow without turbulence or other forces.5. Sampling5.1 Polyesters and polyethers usually contain moleculescovering an appreciable range of molecular weights. Thesehave a tendency to fractionate
8、during solidification. Unless thematerial is a finely ground solid it is necessary to melt (usingno higher temperature than necessary) and mix the resin wellbefore removing a sample for analysis. Many polyols arehygroscopic and care should be taken to provide minimumexposure to atmospheric moisture
9、during the sampling.TEST METHOD ABROOKFIELD VISCOSITY6. Summary of Test Method6.1 The viscosity of resins is measured by determining thetorque on a spindle rotating at constant speed in the liquidsample which is adjusted to 25 6 0.1C. Samples with viscosi-ties exceeding 100 000 mPas(cP) at 50C are d
10、issolved inn-butyl acetate (or other solvent) and the viscosity is deter-mined at 25 6 0.1C.7. Apparatus7.1 Constant-Temperature Bath, capable of maintainingtemperatures of 25 6 0.1C and 50 6 0.1C should be used.Water, water and glycerin, or oil may be used as the heatingmedium and the bath should b
11、e provided with heating, stirring,and thermostatting devices.7.2 Bath and Sample Thermometers, graduated in 0.1Csubdivisions and standardized for the range of use to thenearest 0.01C. ASTM Saybolt Viscosity Thermometers hav-ing ranges from 19 to 27C and 49 to 57C, as specified, and1These test method
12、s are under the jurisdiction of ASTM Committee D20 onPlastics and is the direct responsibility of Subcommittee D20.22 on CellularMaterials - Plastics and Elastomers.Current edition approved Nov. 1, 2008. Published November 2008. Originallyapproved in 1988. Last previous edition approved in 2003 as D
13、 4878 - 03.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Instit
14、ute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.conforming to the requirements for Thermometers 17C and19C, respectively, as prescribed in Specification E1a
15、re rec-ommended.7.3 Brookfield Synchrolectric Viscometer4Model LVFwith speeds of 60, 30, 12, and 6 r/min is to be used whenavailable. It is applicable to the range of 10 to 100 000mPas(cP). If this model is not available, Model RVF or HAFmay be substituted. However, samples should be heated ordissol
16、ved in the standard way to keep the measured viscositybelow 100 000 mPas(cP) so that the test may be repeated inother laboratories under similar conditions with Model LVF.The calibration of the instrument should be checked periodi-cally by measuring the viscosity of Brookfield EngineeringLaboratorie
17、s viscosity standard fluids.4Standard fluids L-2,L-3, R-1, R-2, H-1 are suitable for the usual range. Thecalibration corrections should be applied to sample measure-ments.8. Solvent8.1 n-Butyl Acetate, reagent grade.9. Preparation of Sample9.1 The preparation of a homogeneous sample is of primaryimp
18、ortance in viscosity measurements. A nonuniform tempera-ture distribution as well as the presence of air bubbles andtraces of extraneous material should be avoided. Resins are noteasily made homogeneous with respect to temperature, there-fore, the sample should be thoroughly mixed and the tempera-tu
19、re measured at several locations in the sample vessel beforedetermining the viscosity.10. Preparation of Apparatus10.1 Attach the viscometer with an adjustable clamp to aring stand. Adjust the legs at the base of the ring stand until thebubble is in the center of the spirit level on the viscometer.A
20、ttach the spindle that applies to the range expected for thesample (see Section 12).11. Choice of Temperature11.1 Samples that are liquid and have a viscosity of less than100 000 mPas(cP) at 25C should be measured at that tem-perature. Materials that fulfill this requirement only whenheated from 25
21、to 50C should be measured at 50C. If thesample viscosity exceeds 100 000 mPas(cP) at 50C, thesample may be dissolved in n-butyl acetate (70 or 35 % solids)and the viscosity of the solution measured at 25C.12. Choice of Spindle and Rotational Speed12.1 The recommended Brookfield synchrolectric viscom
22、-eter models offer a variety of spindle size and rotational speeds.In the case of non-Newtonian liquids, changing these factorswill cause variation in the results obtained. In general, thefollowing recommendations should guide in the choice ofspindle size and speed to be used for a specific sample.
23、(SeeTable 1.)12.1.1 The combination chosen should give an instrumentreading near the center of the scale (that is, 175 to 325 on the500 scale).12.1.2 The lowest possible speed consistent with fulfillingthe requirement given in 12.1.1 should be used in order todeemphasize certain types of non-Newtoni
24、an behavior.12.1.3 If these two recommendations conflict, the require-ments given in 12.1.1 have preference.13. Procedure13.1 Place sufficient sample in a 600-mL low-form beakerto cover the immersion mark on the viscometer spindle. Coverthe beaker with a watch glass and immerse to the sample levelin
25、 the constant temperature bath. Stir occasionally withouttrapping air bubbles. Check the temperature at several differentlocations in the beaker to make sure uniformity has beenachieved.13.2 After the desired temperature has been observedthroughout the sample for 10 min, immerse the viscometerspindl
26、e and guard into a sample to the immersion line markedon the spindle. Exercise caution to avoid air bubbles gatheringunder the spindle during immersion. If bubbles are observed,detach the spindle, keeping it in the sample, and stir until thebubbles are released. Reinsert the spindle.13.3 Press down
27、the viscometer clutch lever and start themotor by snapping the toggle switch. Release the clutch leverand allow rotation to continue until the spindle has made eightor ten revolutions. Depress the clutch lever, stop the motor, andread the scale. If, when operating at higher speeds the pointeris not
28、in view when the dial has come to rest, throw the motorswitch on and off rapidly until the pointer reaches the window.4The sole source of supply of the apparatus known to the committee at this timeis Brookfield Engineering Laboratories, 240 Cushing Street, Stoughton, MA 02072.If you are aware of alt
29、ernative suppliers, please provide this information to ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.TABLE 1 Correction Factors Corresponding to VariousCombinations of Spindle and Rotational S
30、peedsModelSpindleNumberCorrection FactorsRotational speed, r/min 6 12 30 60LVF 1 2 1 0.4 0.2210521340 20 8 44 200 100 40 20Rotation speed, r/min 2 4 10 20RVF 110521240 20 8 43 100 50 20 104 200 100 40 205 400 200 80 406 1 000 500 200 1007 4 000 2 000 800 400Rotational speed, r/min 1 2 5 10HAF 1 40 2
31、0 8 42 160 80 32 163 400 200 80 404 800 400 160 805 1 600 800 320 1606 4 000 2 000 800 4007 16 000 8 000 3 200 1 600D 4878 08213.4 Repeat the procedure until three readings on the 500scale agree within five units.14. Calculation14.1 Multiply readings on the 500 scale by the factors givenin Table 1 t
32、o obtain viscosity in mPas(cP). If the instrumentscale is 0 to 100, multiply the calculated result by five.14.2 At 60 r/min, air resistance on the pointer has a certaineffect. Values obtained should be reduced as follows:14.2.1 No. 1 spindle, deduct 0.4 mPas(cP),14.2.2 No. 2 spindle, deduct 2.0 mPas
33、(cP),14.2.3 No. 3 spindle, deduct 8.0 mPas(cP), and14.2.4 No. 4 spindle, deduct 40.0 mPas(cP).14.3 Apply all calibration corrections mentioned in 7.3.15. Report15.1 Report the following information:15.1.1 Temperature of test,15.1.2 Solids content and solvent,15.1.3 Model of viscometer,15.1.4 Speed o
34、f rotation,15.1.5 Spindle number, and15.1.6 Viscosity in millipascal seconds (centipoises)mPas(cP).16. Precision and Bias16.1 PrecisionAttempts to develop a precision and biasstatement for this test method have not been successful;however, the precision is expected to be equivalent to thatreported b
35、y the instrument manufacturer. For this reason, dataon precision and bias cannot be given. Because this test methoddoes not contain a numerical precision and bias statement, itshall not be used as a referee test method in case of dispute.Anyone wishing to participate in the development of precisiona
36、nd bias data should contact the Chairman, SubcommitteeD20.22 (Section D20.22.01), ASTM, 100 Barr Harbor Drive,West Conshohocken, PA 19428.16.2 BiasThe bias of this test method has not yet beendetermined.TEST METHOD BCANNON-FENSKE17. Test Method17.1 A general method for Cannon-Fenske viscosity whicha
37、pplies to polyols as well as other materials is published in TestMethod D 445.18. Keywords18.1 Brookfield; Cannon-Fenske; polyols; polyurethane rawmaterials; viscosityASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin th
38、is 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 and must b
39、e 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 of theres
40、ponsible 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 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 4878 083
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