1、Designation: D4878 08D4878 15Standard Test Methods forPolyurethane Raw Materials: Determination of Viscosity ofPolyols1This standard is issued under the fixed designation D4878; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the y
2、ear 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 Scope*1.1 These test methods (A and B) determine the viscosity of polyols in the range from 10 to 100 000 mPas(cP)
3、 at 25C or at50C. 25C. Test Method A also applies to more viscous samples that are soluble in is a rotational procedure for determiningdynamic viscosity. n-butyl acetate. Test Method B is simply a reference to a a general procedure for kinematic viscosity,viscosityD445. of transparent polyols. (See
4、Note 1.)1.2 The values stated in SI units are to be regarded as the standard. Other equivalent units are provided because of currentcommon usage.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 stan
5、dard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.NOTE 1There is no equivalent ISO standard for Test Method A although ISO 3219 is similar.is equivalent to ISO 3219. Test Method B is equivalentto ISO 3104.2. Referenced Doc
6、uments2.1 ASTM Standards:2D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)D446 Specifications and Operating Instructions for Glass Capillary Kinematic ViscometersD883 Terminology Relating to PlasticsE1E2251 Specification for ASTM Liqui
7、d-in-Glass ThermometersLiquid-in-Glass ASTM Thermometers with Low-HazardPrecision Liquids2.2 ISO Standards:3ISO 3104 ISO 3104 Petroleum ProductsTransparent and Opaque LiquidsDetermination of Kinematic Viscosity andCalculation of Dynamic ViscosityISO 3219 ISO 3219 PlasticsPolymers/Resins in the Liqui
8、d State of as Emulsions or DispersionsDetermination of ViscosityUsing a Rotational Viscometer with Defined Shear Rate3. Terminology3.1 For definitions of terms used in these test methods see Terminology D883.4. Significance and Use4.1 These test methods are suitable for research or as quality contro
9、l or specification tests.4.2 Viscosity measures the resistance of a fluid to uniformly continuous flow without turbulence or other forces.5. Sampling5.1 PolyestersPolyester and polyethers usuallypolyether polyols contain molecules covering an appreciable range of molecularweights. These have a tende
10、ncy to can fractionate during solidification. Unless the material is a finely ground solid it is necessary1 These test methods are under the jurisdiction ofASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.22 on Cellular Materials - Plasticsand Elastomers.Current ed
11、ition approved Nov. 1, 2008May 1, 2015. Published November 2008June 2015. Originally approved in 1988. Last previous edition approved in 20032008 asD4878 - 03.D4878 - 08. DOI: 10.1520/D4878-08.10.1520/D4878-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Custom
12、er Service at serviceastm.org. ForAnnual Book ofASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 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
13、ASTM standard 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
14、 all cases 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 States1to melt
15、 (using no higher temperature than necessary) and mix the resinpolyol well before removing a sample for analysis. Manypolyols are hygroscopic and care should be taken to provide minimum exposure to atmospheric moisture during the sampling.TEST METHOD ABROOKFIELDAROTATIONAL VISCOSITY6. Summary of Tes
16、t Method6.1 The viscosity of resins is measured by determining the torque on a spindle rotating at constant speed in the liquid samplewhich is adjusted to 2560.1C. Samples with viscosities exceeding 100 000 mPas(cP) at 50C are dissolved inat 2560.1C.Generation of comparative data using this method r
17、equires agreement on the nspeed,-butyl acetate (or other solvent) and theviscosity is determined at 2560.1C. spindle, temperature, time of rotation, and torque range of the instrument used.7. Apparatus7.1 Constant-Temperature Bath, capable of maintaining temperatures a temperature of 2560.1C and 506
18、0.1C should is tobe used. Water, water and glycerin, or oil may be is used as the heating medium and the bath should is to be provided with heating,stirring,circulating, and thermostatting devices.7.2 Bath and Sample Thermometers, graduated in 0.1C subdivisions and standardized for the range of use
19、to the nearest0.01C. ASTM Saybolt Viscosity Thermometers having ranges from 19 to 27C and 49 to 57C, as specified, and conforming tothe requirements for Thermometers 17CS117C and 19C,S64C, respectively, as prescribed in Specification E1E2251 arerecommended. Any other thermometric device of equal or
20、better accuracy is also acceptable.7.3 Brookfield Synchrolectric ViscometerRotational Viscometer Model LVF with speeds of 60, 30, 12, and 6 r/min is to beused when available. It is applicable to the range of 10 to 100 000 mPas(cP). If this model is not available, Model RVF or HAFmay be substituted.
21、However, samples should be heated or dissolved in the standard way to keep the measured viscosity below100 000 mPas(cP) so that the test may be repeated in other laboratories under similar conditions with Model LVF. Capable of userdefined speed and spindle combinations.An instrument that is capable
22、of providing the shear rate is recommended. The calibrationof the instrument should is to be checked periodically by measuring the viscosity of Brookfield Engineering Laboratories viscosityNIST traceable standard fluids. Standard fluids L-2, L-3, R-1, R-2, H-1 are suitable for the usual range. The c
23、alibration correctionsshould be applied to sample measurements.8. Solvent8.1 Cleaning Solventn-Butyl Acetate,methanol or acetone, reagent grade. Any solvent in which the polyol is completelymiscible is acceptable.9. Preparation of Sample9.1 The preparation of a homogeneous sample is of primary impor
24、tance in viscosity measurements. A nonuniformnon-uniformtemperature distribution as well as the presence of air bubbles and traces of extraneous material should be avoided. Resins are noteasily made homogeneous with respect to temperature, therefore, the sample shouldare to be avoided. The sample mu
25、st bethoroughly mixed and the temperature measured at several locations in the sample vessel before determining the viscosity.10. Preparation of Apparatus10.1 Attach the viscometer with an adjustable clamp to a ring stand.Adjust the legs at the base of the ring stand until the bubbleis in the center
26、 of the spirit level on the viscometer.Attach the spindle that applies to the range expected for the sample (see SectionFollow the manufacturers instructions to set up the instrument and ensure that the viscometer is level.12).11. Choice of Temperature11.1 Samples that are liquid and have a viscosit
27、y of less than 100 000 mPas(cP) at 25C should be measured at that temperature.Materials that fulfill this requirement only when heated from 25 to 50C should are to be measured at 50C. If the sample viscosityexceeds 100 000 mPas(cP) at 50C, the sample may be dissolved in n-butyl acetate (70 or 35 % s
28、olids) and the viscosity of thesolution measured at 25C.11.2 In cases of interlaboratory studies and higher viscosity samples, all parties are to agree upon a set measurementtemperature.12. Choice of Spindle and Rotational Speed12.1 The recommended Brookfield synchrolectric viscometer models Rotatio
29、nal viscometers offer a variety of spindle size androtational speeds. In the case of non-Newtonian liquids, changing these factors will cause variation in the results obtained. Ingeneral, the following recommendations should guide in the choice of provide guidance for choosing the spindle size and s
30、peedto be used for a specific sample. (See Table 1.)D4878 15212.1.1 The combination chosen should give an instrument reading near the center of the scale (that is, 175 to 325 on the 500scale).12.1.1 The lowest possible speed consistent with fulfilling the requirement given incombination chosen shall
31、 generate a torquevalue between 15 and 12.1.1 should be used in order to deemphasize certain types of non-Newtonian behavior. 90 % of full scale,or that specified by the instrument manufacturer.12.1.1.1 If more than one speed/spindle combination will fulfill the requirement of 12.1.1, the combinatio
32、n with the higherspeed will provide higher accuracy and the combination with the lower speed will minimize certain types of non-Newtonianbehavior.12.1.1.2 There must be agreement between the testing laboratory and the submitter on the spindle, speed selection.12.1.3 If these two recommendations conf
33、lict, the requirements given in 12.1.1 have preference.13. Procedure13.1 Place sufficient sample in a 600-mL low-form beaker Using the smallest container recommended by the manufacturer,place sufficient sample to cover the immersion mark on the viscometer spindle. Cover the beaker with a watch glass
34、 container andimmerse it to the sample level in thea constant temperature bath. Stir occasionally without trapping air bubbles. Check thetemperature at several different locations in the beakercontainer to make sure ensure uniformity has been achieved.13.2 After the desired temperature has been obse
35、rved throughout the sample for 10 min, immerse the viscometer spindle andguard (and the guard when recommended by the manufacturer) into a sample to the immersion line marked on the spindle. Exercisecaution to avoid air bubbles gathering under the spindle during immersion. If bubbles are observed, d
36、etach the spindle, keepingit in the sample, and stir until the bubbles are released. ReinsertReattach the spindle.13.3 Press down the viscometer clutch lever and start the motor by snapping the toggle switch. Release the clutch lever andallow rotation to continue until the spindle has made eight or
37、ten revolutions. Depress the clutch lever, stop the motor, and readthe scale. If, when operating at higher speeds the pointer is not in view when the dial has come to rest, throw the motor switchon and off rapidly until the pointer reaches the window. Follow the manufacturers instructions to measure
38、 the viscosity for thesample using a 15-second rotation time.13.4 Repeat the procedure until three readings on the 500 scale agree within five units. After the analysis, spindles are cleanedwith a solvent appropriate for the polyol and equipment used, for example, methanol or acetone.14. Calculation
39、14.1 Multiply readings on the 500 scale by the factors given inthe reading by the factor provided by Table 1 to obtain viscosityin mPas(cP). If the instrument scale is 0 to 100, multiply the calculated result by five.the manufacturer for the speed/spindlecombination used to convert the instrument re
40、ading to the viscosity in mPas (cP). Most instruments automatically perform thiscalculation.14.2 At 60 r/min, air resistance on the pointer has a certain effect. 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(cP),14.2.3 No
41、. 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,15.1.2 Model of viscometer,15.1.3 Speed of rotation,15.
42、1.4 Spindle number, and15.1.5 Viscosity in millipascal seconds (centipoises) mPas(cP).16. Precision and Bias16.1 PrecisionAttempts to develop a precision and bias statement for this test method have not been successful; however, theprecision is expected to be equivalent to that reported by the instr
43、ument manufacturer. For this reason, data on precision and biascannot be given. Because this test method does not contain a numerical precision and bias statement, it shall not be used as a refereetest method in case of dispute. Anyone wishing to participate in the development of precision and bias
44、data should contact theChairman, Subcommittee D20.22 (Section D20.22.01), ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428.16.2 BiasThe bias of this test method has not yet been determined.D4878 153TEST METHOD BCANNON-FENSKE BKINEMATIC VISCOSITY17. Summary of Test Method17.1 The viscosity of
45、 polyols is measured by determining the time it takes a fixed volume of liquid to flow under gravity controlthrough a calibrated capillary glass viscometer under a reproducible driving head at 25 6 0.1C. The kinematic viscosity isdetermined by multiplying the flow time by the calibration factor of t
46、he viscometer.18. Apparatus18.1 Additional details of equipment can be found in Specifications D446.18.2 Constant-Temperature Bath, capable of maintaining a temperature of 25 6 0.1C and 50 6 0.1C is to be used. Water,water and glycerin, oil, or any other transparent thermal transfer liquid is to be
47、used as the heating medium and the bath is to beof sufficient depth and to be provided with heating, circulating, and thermostatting devices.18.3 Thermometers, graduated in 0.1C subdivisions and standardized for the range of use to the nearest 0.01C.ASTM SayboltViscosity Thermometers having ranges f
48、rom 19 to 27C and 49 to 57C, as specified, and conforming to the requirements forThermometers S117C and S64C, respectively, as prescribed in Specification E2251 are recommended. Any other thermometricdevice of equal or better accuracy is also acceptable.18.4 Glass capillary viscometer, calibrated by
49、 the manufacturer.18.5 Timing device, capable of reading to the nearest 0.1 s or better, with an accuracy of 60.07 % of the reading when testedover the intervals of 200 and 900 s.19. Solvents19.1 Methanol or Acetone, reagent grade. Any solvent in which the polyol is completely miscible is acceptable.20. Preparation of Sample20.1 The preparation of a homogeneous sample is of primary importance in viscosity measurements. The presence of airbubbles and traces of extraneous material are to be avoided. The sample is to be thoroug
