1、Designation: D4212 10 (Reapproved 2014)D4212 16Standard Test Method forViscosity by Dip-Type Viscosity Cups1This standard is issued under the fixed designation D4212; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、 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 This test method covers the determination of viscosity of paints, varnishes, lacquers, inks, and related liquid materials
3、bydip-type viscosity cups. This test method is recommended for viscosity control work within one plant or laboratory and should beused to check compliance with specifications only when sufficient controls have been instituted to ensure adequate comparabilityof results.1.2 Viscosity cups are designed
4、 for testing of Newtonian and near-Newtonian liquids. If the test material is non-Newtonian, forexample, shear-thinning or thixotropic, another method, such asTest Methods D2196, should be used. Under controlled conditions,comparisons of the viscosity of non-newtonian materials may be helpful, but v
5、iscosity determination methods using controlledshear rate or shear stress are preferred.1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.4 This standard does not purport to address all of the safety concerns, if any, ass
6、ociated 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 to use.2. Referenced Documents2.1 ASTM Standards:2D1200 Test Method for Viscosity by Ford Viscosity CupD2196
7、Test Methods for Rheological Properties of Non-Newtonian Materials by Rotational ViscometerD4287 Test Method for High-Shear Viscosity Using a Cone/Plate ViscometerE1 Specification for ASTM Liquid-in-Glass Thermometers3. Terminology3.1 Definitions:3.1.1 near-Newtonian liquid, na liquid in which the v
8、ariation of viscosity with shear rate is small and the effect on viscosityof mechanical disturbances such as stirring is negligible.3.1.2 Newtonian liquid, na liquid in which the viscosity is independent of the shear stress or shear rate. If the ratio of shearstress to shear rate is not constant, th
9、e liquid is non-Newtonian.4. Summary of Test Method4.1 The cup is completely immersed in the material to be tested, withdrawn, and the time for the material to flow through a holein the base of the cup is measured.5. Significance and Use5.1 Viscosity is a measure of the fluidity of a material. Visco
10、sity data are useful in the determination of the ease of stirring,pumping, dip coating, or other flow-related properties of paints and related fluids.5.2 This type of cup is used to measure viscosity because it is easy to use, robust, and may be used in tanks, reservoirs, andreactors.1 This test met
11、hod is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.24 on Physical Properties of Liquid Paints and cups Nos. 3 and 4 are for use with more viscous paints and inks (No. 3 for manufacturing o
12、f flexographic inks);and cup No. 5 is used for silk screen inks.NOTE 1Dimensions are approximate only and may vary with the manufacturer and from batch to batch.FIG. 1 Zahn Cup Nominal DimensionsD4212 1626.2 Shell Viscosity Cup3No. 1 through No. 6 Shell viscosity cups made of stainless steel with a
13、capacity of 23 mL and a25-mm (1-in.) long capillary in the bottom and conforming to the dimensions shown in Fig. 2.6.2.1 Nominal Shell cup orifice diameters are listed in Table X2.1. Cup Nos. 1 through 212 are recommended for use withreduced rotogravure inks; No. 2 is for use with flexographic inks;
14、 Nos. 3 through 4 are used for industrial enamels, lacquers,flexographic, and gravure inks; Nos. 5 and 6 are used for heavy materials.6.3 Calibration ThermometerASTM Saybolt Viscosity Thermometer 17F having a range of 66 to 80F and subdivisions of0.2F, or 17C having a range of 19 to 27C and subdivis
15、ions of 0.1C, both conforming to the requirements of Specification E1.Thermometers having subdivisions other than these may be used depending on the sensitivity of the material to be tested, thedemands of the application, and the agreement between the purchaser and seller. In addition, temperature m
16、easuring devices suchas non-mercury liquid-in-glass thermometers, thermocouples, or platinum resistance thermometers that provide equivalent or betteraccuracy and precision, that cover the temperature range for thermometer 17C and 17F, may be used.6.4 TimerAny timing device may be used provided that
17、 the readings can be taken with a discrimination of 0.1 s or better.7. Test Materials7.1 The material to be tested should be visibly homogeneous and free from any foreign material or air bubbles.8. Temperature of Testing8.1 Measurements should be made at 25C (77F) unless otherwise specified. Tempera
18、ture drift during the test should be keptto a minimum. The viscosities of paints and related materials are highly dependent on temperature. Differences in temperaturebetween measurements can give substantially different viscosities (up to 5 % per F). For careful work, the temperature should betaken
19、in the efflux stream, but for process control (such as monitoring a dip tank), this is not necessary.8.2 A temperature correction curve may be constructed for each liquid by plotting viscosity (seconds) against temperature overthe expected temperature range. With this curve, a viscosity determined a
20、t one measured temperature may be converted quicklyto a viscosity at another temperature.NOTE 2When dip cups are used for original purposes, that is thinning or monitoring of materials in tanks, coaters, etc., temperature is not important.This is because the key to good operation is to maintain the
21、fluid within a certain range of dip cup-seconds regardless of the temperature of the fluid.3 Shell cups may be obtained from the Norcross Corp., 255 Newtonville Ave., Newton, MA 02158. This committee is not aware of any other source for flow cups havingproperties similar enough to the Shell cup to b
22、e included in this test method. If you have knowledge of a cup that should be considered, please provide details to ASTMInternational Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee,1 which you may attend.FIG. 2 Shell CupD4212 1639.
23、Checking and Calibration of Cups9.1 Cups should be checked in accordance with the procedure described in Appendix X2. The frequency of this depends uponthe amount of use and care that the individual cup receives, and the level of precision required.9.2 Cups may be calibrated with standard fluids acc
24、ording to the procedure in Appendix X3. However, because the viscosityof standard fluids can vary significantly with temperature and due to difficulty in obtaining adequate temperature control with dipcups, calibration is a difficult procedure that must be done with great care and knowledge.10. Proc
25、edure10.1 Choose the proper cup so that the time of efflux will be between 20 and 80 s. See Table 1 for viscosity ranges for the variouscups.NOTE 3The formulas used in this test method to describe the conversion from Zahn seconds to stokes are linear, the actual cup response is not. Therange of 20 t
26、o 80 s covers the most linear portion of each cup. In addition, below 20 s, turbulent flow may cause additional inconsistencies. Above 80s, factors that may impact on the precision include; loss of solvent (and therefore varying viscosity), “skinning” of the liquid in the cup, intermittent flow.10.2
27、 Immerse the cup in the container, which may be a can or beaker, but is more likely to be a thinning or mixing tank or evena resin reactor. Stir or agitate the fluid well to give uniform temperature and density. Allow the cup to remain in the fluid for 1to 5 min to attain thermal equilibrium. (Becau
28、se of their greater mass, Shell cups should remain in the fluid for the full 5 min.)NOTE 4Dip cups are not recommended for use with thixotropic (time dependent) materials but if used for them (such as gravure or flexographic inks),more vigorous agitation will be necessary to break up the structure b
29、efore the measurement is made.10.3 Lift the cup vertically out of the material in a quick, steady motion. As the top edge of the cup breaks the surface, startthe timer. During the time of flow, hold the cup vertically no more than 15.2 cm (6 in.) above the level of the liquid. Stop the timerat the f
30、irst definite break in the stream at the base of the cup. The efflux time in seconds constitutes the viscosity. It is commonto make only a single measurement, but for greater precision and accuracy the mean of two or more measurements should be taken.NOTE 5The cup should not be held by the loop hand
31、le during the measurement process. Most manufacturers equip the cup with a ring through theloop handle. Holding the cup by this ring will help to ensure that the cup hangs vertically.11. Care of Cups11.1 Following each determination, clean the cup with a suitable solvent and a soft brush. Use no met
32、al tools in contact withthe instrument as nicks or wear of the drilled orifice affect the accuracy of the cup.12. Report12.1 Report the efflux time to the nearest 0.2 s for Zahn or Shell cup No. _, manufactured by _, (in the case of Zahncups) the temperature of the fluid (where measured), and whethe
33、r the result is from a single measurement or the mean of two ofmore measurements.13. Precision and Bias13.1 The most satisfactory results when using dip cups are obtained when viscosity is being controlled at a single location only.However, when comparisons between locations are made, cups from the
34、same manufacturer must be used or other action takento ensure compatibility of results. The following criteria can be used for judging the acceptability of results at the 95 % confidencelevel:13.1.1 Zahn CupsPrecision was determined on the basis of an interlaboratory test in which six laboratories u
35、sed new Zahncups (all from the same set from the same manufacturer) to test eight paints covering a broad range of viscosities. Thewithin-laboratory coefficient of variation was 3.7 % and the between-laboratories coefficient of variation was 11.5 %. Based onthese coefficients the following criteria
36、should be used for judging the acceptability of results at the 95 % confidence level:TABLE 1 Approximate Viscosity Ranges, cST (mm2/s) (RoughlyCorresponding to 20 to 80 s Flow Time)Cup Number Zahn Cup Shell Cup1A 560 2202 20250 1050212 . 20803 100800 30120312 . 401704 2001200 702705 4001800 1255206
37、. 3201300A The lower limit for the Zahn No. 1 cup is 35 s rather than 20 s.D4212 16413.1.1.1 RepeatabilityTwo results, each the mean of two measurements, obtained by the same operator should be consideredsuspect if they differ by more than 11 % of their mean value.13.1.1.2 ReproducibilityTwo results
38、, each the mean of two measurements, obtained by operators in different laboratoriesshould be considered suspect if they differ by more than 33 % of their mean value.NOTE 6The values used to determine the precision were obtained under ideal conditions (a single set of cups), reproducibility in pract
39、ice can be justas good, by employing strict controls and good techniques.13.1.1.3 BiasBias does not apply to this test method as no acceptable standards exist.NOTE 7Since the precision values were obtained under ideal conditions (a single set of cups), reproducibility in practice probably is poorer
40、than thatgiven (perhaps as bad as 50 %).13.1.2 Shell CupsPrecision was determined on the basis of an interlaboratory test in which four laboratories tested sevenpaints covering a broad range of viscosities. The within-laboratory coefficient of variation was 3.2 % and the between-laboratoriescoeffici
41、ent of variation was 6.3 %. Based on these coefficients the following criteria should be used for judging the acceptabilityof results at the 95 % confidence level:13.1.2.1 RepeatabilityTwo results, each the mean of two measurements, obtained by the same operator should be consideredsuspect if they d
42、iffer by more than 9 % of their mean value.13.1.2.2 ReproducibilityTwo results, each the mean of two measurements, obtained by operators in different laboratoriesshould be considered suspect if they differ by more than 18 % of their mean value.13.1.2.3 BiasBias does not apply to this test method as
43、no acceptable standards exist.14. Keywords14.1 dip cup(s); flow cup(s); Shell cup(s); viscosity; Zahn cup(s)APPENDIXES(Nonmandatory Information)X1. ZAHN CUP DESIGN, MANUFACTURE, AND USEX1.1 Zahn cups were designed (and manufactured by General Electric) as simple flow property devices for use in dip
44、tanks, flowcoat reservoirs, etc. They were not designed to be viscometers or to be used as such. Zahn cup use usually involves thinning ormaintaining a coating, adhesive, or ink at a certain consistency (so many Zahn-seconds) regardless of temperature. This is thebeauty of dip cups. The operator kno
45、ws that his or her tank, bath, or coater runs well over a certain range of Zahn-seconds whetherthe plant temperature is 50F or 100F. The operator does whatever is necessary to keep the fluid within the range. In such anapplication the viscosity at 25.0C (77.0F) is not important.X1.2 Zahn cup patents
46、 have expired and Zahn-type cups are available from several sources. Each manufacturer makes cups thatare somewhat different from those made by others. Considerable batch-to-batch difference has been noted in the past from somemanufacturers. Cup variations are not a problem for consistent control of
47、 a bath or tank as long as appropriate comparisons aremade with old cups, if required, to maintain continuity of data. However, cup differences can cause great difficulty if cups are usedto set producer-user specifications. Comparisons under such conditions require considerable attention to detail a
48、nd practicedexpertise.X2. DIP CUP CHECKING PROCEDURESX2.1 The viscosity versus efflux time formulas published here are in wide use, however, not all Zahn-type cups are designed tocomply with these formulas. Techniques for ensuring continued calibration of cups that do not claim compliance with these
49、formulas include; comparison of current flow times for a standard fluid against the original flow time, and comparison against averified standard cup. The same calibration verification methods of comparing a cup against one in known condition applied toZahn-type cups can be used with Shell cups.X2.2 Monitoring Cup CharacteristicsA useful checking technique is to measure the efflux time for a new cup with a givenstandard fluid, then check the cup periodically with the same oil at the same temperature to determine if the efflux tim
copyright@ 2008-2019 麦多课文库（www.mydoc123.com）网站版权所有
备案/许可证编号：苏ICP备17064731号-1