1、Designation: D 4040 05Standard Test Method forRheological Properties of Paste Printing and Vehicles by theFalling-Rod Viscometer1This standard is issued under the fixed designation D 4040; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revi
2、sion, 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 This test method covers the procedure for determiningthe falling-rod viscosity and degree of non-N
3、ewtonian behav-ior of printing inks, vehicles, and similar liquids that areessentially nonvolatile and unreactive under ordinary roomconditions.1.2 For printing inks, which are typically non-Newtonian,this test method is applicable in the apparent viscosity rangefrom about 10 to 300 P at a shear rat
4、e of 2500 s1. ForNewtonian liquids, the applicable viscosity range is about 10 to1000 P (1 P = 0.1 Pas).1.3 This test method uses a falling-rod viscometer in whichshear conditions are altered by manually adding weight to therod. A fully automatic instrument is described in Test MethodD 6606.1.4 This
5、 test method, as does Test Method D 6606, basescalculations on the power law model of viscosity. ISO 12644covers not only the power law but also the Casson andBingham models.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.
6、6 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 prior to use. For specific haz
7、ardstatements, see Section 8.2. Referenced Documents2.1 ASTM Standards:2D 445 Test Method for Kinematic Viscosity of Transparentand Opaque LiquidsD 6606 Test Method for Viscosity andYield of Vehicles andVarnishes by the Duke Viscometer2.2 Other Standards:ISO 12644 Graphic TechnologyDetermination of
8、rheo-logical properties of past inks and vehicles by the fallingrod Viscometer3. Terminology3.1 Definitions:3.1.1 apparent viscosity, VD, nthe viscosity of a non-Newtonian fluid at a particular shear rate D.3.1.1.1 DiscussionAshear rate of 2500 s1has been founduseful for printing inks and is specifi
9、ed in this test method.3.1.2 Newtonian, adjrefers to a liquid whose viscosity isconstant at all shear rates.3.1.3 non-Newtonian, adjrefers to a liquid whose viscos-ity varies with shear rate.3.1.3.1 DiscussionNon-Newtonain liquids may be eithershear-thinning (pseudoplastic) or shear-thickening (dila
10、tant).Most printing inks are shear-thinning.3.1.4 shear rate, D, nvelocity gradient through thestressed liquid; the unit is 1/s or 1 s1.3.1.4.1 DiscussionIn the falling-rod viscometer, shearrate is inversely proportional to fall time F per unit distance Lover which a unit thickness x of the liquid i
11、s stressed:D = L/xF.3.1.5 shear stress, S, nshearing force per unit area; theunit is 1 g/cms2(1 dyne/cm2).3.1.5.1 DiscussionIn the falling-rod viscometer, shearstress is proportional to total weight W per unit of shearing areaA times the gravitational constant g, in accordance with theequation: S =
12、Wg/A.3.1.6 viscosity, V, nthe ratio of shear stress to shear rate.3.1.6.1 DiscussionThe viscosity of a liquid is a measureof the internal friction of the liquid in motion. The cgs unit ofviscosity is 1 g/cms (1 dynes/cm2) and is called a poise. TheSI unit is 1 Ns/cm2and is equal to 10 P.3.1.7 yield
13、stress, So, nthe minimum shear stress requiredto initiate motion in a non-Newtonian liquid.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, andApplications and is the direct responsibility ofSubcommittee D01.56 on Printing Inks.Current editio
14、n approved May 15, 2005. Published July 2005. Originallyapproved in 1981. Last previous edition approved in 1999 as D 4040 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information,
15、 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 International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2 Definitions of Terms Specific to This Standard:3.2
16、.1 Lehman yield value, ncalculated yield stress basedon the Lehman chart.3.2.2 power law, na mathematical model that presumesthat the viscosity of a liquid varies with shear rate in accor-dance with a power function as follows:k 5SDN(1)where:k = a constant related to the viscosity of the liquid andN
17、 = a constant describing the rate at which shear stressvaries with shear rate.3.2.2.1 DiscussionThe value of N is precisely 1.0 for aNewtonian fluid, less than 1.0 for a shear-thinning liquid, andgreater than 1.0 for a shear-thickening liquid.3.2.3 power law plot, na logarithmic plot of shear stress
18、versus shear rate based on the expanded form of the power lawequation:ln S 5 ln k 1 N ln D (2)3.2.3.1 DiscussionFor liquids conforming to the powerlaw, the logarithmic plot of S versus D is linear over the shearrate range of interest. The slope of the line is the power lawconstant N.3.2.4 pseudo yie
19、ld value, ncalculated yield stress devel-oped for use with the power law.3.2.5 shortness, nthe property of a non-Newtonian fluidthat prevents it from being drawn into a filament.3.2.6 shortness factor (also called shortness ratio), nratioof yield value to viscosity.3.3 Symbols: (for Power-Law Calcul
20、ations):B = intercept of a straight line.F = measured fall time, s.Fc= corrected fall time, s.F2500= fall time equivalent to a shear rate of 2500 s1,s.K2500= apparent viscosity constant at 2500 s1,cm1s1.N = slope of the power law plot, a measure ofnon-Newtonianism, cm2/dynes.SF = shortness factor, s
21、1.S8o= pseudo yield value, dyne/cm2SoL= Lehman yield value, dyne/cm2.T = measured specimen temperature, C.TR= reference temperature, C.V2.5= apparent viscosity at 2.5 s1,P.V2500= apparent viscosity at 2500 s1,P.W = total weight, g.WA= added weight, g.WR= weight of rod, g.W2500= weight required to ob
22、tain a shear rate of 2500 s1,g.4. Summary of Test Method4.1 This test method is based on measurements of the timerequired for a weighted rod to fall through an aperturecontaining the test specimen.4.2 Fall times are corrected to a reference temperature of25C (or other mutually agreed-upon temperatur
23、e). The testmethod specifies precise measurement of actual specimentemperature in order to detect fluctuations due to cooling bymetal, heat of friction during shearing, and body heat of theoperator.4.3 Each specific instrument must be calibrated in order toestablish the fall time that is equivalent
24、to a shear rate of 2500s1.4.4 Fall times as a function of weight are extrapolated to2500 s1by means of the power law (logarithmic) relationshipbetween shear stress and shear rate.Apparent viscosity at 2500s1and the degree of non-Newtonianism are determined bycalculation or graphically. The calculati
25、on of several low shearparameters is also covered.5. Significance and Use5.1 Apparent viscosity at the relatively high shear rate of2500 s1does not completely define the rheological propertiesof printing inks but is useful in the practical control of inkviscosity during production and the specificat
26、ion acceptancebetween supplier and purchaser.5.2 The slope of the power law plot is the preferred measureof non-Newtonianism. The yield value, which is obtained byextrapolation of high-shear measurements to a shear rateapproaching zero, does not conform to the definition of the trueyield stress (see
27、 3.1.7). The yield value and other low shearparameters are also subject to a high degree of variability (seethe precision table in Section 16).6. Apparatus6.1 Fall-Time Runs:6.1.1 Falling-Rod Viscometer, equipped with a swingingplatform and automatic timing device3accurate to at least 0.1s, preferab
28、ly 0.01 s. A special lightweight rod is useful forliquids in the 10-P range.6.1.2 Set of Tapped or Slotted WeightsWeights of 50 or100 to 500 g are usually provided with the instrument. Extra500-g weights, approximately 4, totaling about 2000 g arerequired to handle fluids at the upper end of the pra
29、ctical range.A 25-g weight is useful for liquids in the 10-P range.6.1.3 A Thermostatically Controlled Cabinet or a SpecialCollar,4through which water is circulated from a constant-temperature bath (both are optional if room conditioning is notavailable).6.1.4 Thermistor, spanning the specified test
30、 temperature(usually 25C), accurate to 0.01C, and equipped with a probehaving a response time of 3 to 6 s.6.1.5 Ring Stand and Clamp, or other device for holding thethermistor probe in a suitable position.6.1.6 Small Plastic SpatulaMetal spatulas are not suit-able.6.1.7 Plastic Scraper, consisting o
31、f a piece of flexibleplastic, approximately 30 by 70 mm, having a semicircle cutout at one end; semicircle should fit the rod.3Platform and timing device are standard on newer viscometer models. Forequipping older models, see Bassemir, R, “Evaluation of the Laray Visocmeter,”American Ink Maker, Vol
32、39, No. 4, April 1961, pp. 2426 and 60.4Collars are available as accessories from the respective manufacturers offalling-rod viscometers.D40400526.2 Instrument Calibration:6.2.1 Balance, weighing to 0.1 g.6.2.2 Metric Rule or Scale, at least 100 mm in length.6.2.3 Vernier Caliper, accurate to 0.01 m
33、m, having a capac-ity of at least 30 mm.6.3 Graphical Solutions:6.3.1 Chart Paper, logarithmic 2 3 2to23 3 cycles.6.3.2 Triangle, 45, with a hypotenuse length of at least 100mm (approximately 8 in.).6.3.3 Protractor.7. Materials7.1 ASTM Standard Viscosity Oils,5a minimum of two,preferably three, spa
34、nning the practical range of the falling-rodviscometer (used for calibration purposes only).7.2 Lithographic Varnish or similar vehicle having a vis-cosity of about 200 P (for use in 12.3, if needed).7.3 Lint-and-Metal-Free Rags or Tissues.7.4 Naphtha or other low-boiling solvent in a wash bottleor
35、closed metal container.8. Hazards8.1 Safety PrecautionsSince solvents may be hazardousto the skin and eyes, in addition to other precautions, wearrubber gloves and safety glasses during cleanup to avoidsolvent contact with skin and eyes. In case of contact, washskin with water; flush eyes for 15 min
36、 with water and call aphysician. See suppliers Material Safety Data Sheets forfurther information on each solvent used.8.2 Instrument Cautions:8.2.1 Avoid any operation that will scratch the rod. Do notuse a metal spatula. Never drop the rod through an emptyaperture.8.2.2 Weight loads in excess of 3
37、000 g may cause bendingof the rod.8.2.3 To minimize heat buildup from body temperatureduring a run, avoid contacting the viscometer block with barehands. When instructions call for holding the block steady,wear a glove or place a small cloth in the palm of the hand.8.2.4 When making fall-time measur
38、ements, work quicklyand without interruption so that the entire run is completedwithin 5 to 10 min.NOTE 1Many modern printing inks and vehicles contain some sol-vent, and volatile loss during a run can seriously bias test results unlessrigorous control of exposure time is exercised. Volatile loss ca
39、n bedetected if successive drops of the rod with the same weight result inincreasingly longer fall times.9. Preparation of Apparatus9.1 Set the viscometer on a sturdy bench located in an areafree of direct drafts, direct sunlight, and other sources of heat.Level the viscometer, using the adjustable
40、feet.9.2 Pass a hand over the upper and lower photocells toassure that the timer is activated and deactivated.9.3 Attach the clamp to the ring stand and place next to orbehind the viscometer. Drape the thermistor probe over theclamp; reset the clamp so that the probe end falls close to theviscometer
41、 block.9.4 Clean the block and rod thoroughly with tissues wettedwith naphtha. Remove residual solvent with clean dry tissue.Roll the clean dry rod over a flat surface to check forstraightness. If rod is bent, discard and obtain a new rod/orificeset.9.5 Examine the markings at the ends of the rod. S
42、elect onemarking as an indication of the “proper” end to be alwaysinserted into the aperture first.10. Calibration10.1 Determine instrument constants in accordance with theprocedure given in Annex A1.10.2 OptionalIf a graphical method is to be used fordirect conversion of test results to viscosity,
43、prepare MasterSliding Scale Calibration Graph as in Annex A2.10.3 Periodically check calibration as in A1.2.11. Sample Preparation11.1 Transport the sample to the test area and preserve in aclosed container. Skin paper should be used for oxidativedrying inks.11.1.1 Ink samples should be uniform disp
44、ersions. If pig-ment settling is suspected, insert a spatula in the container andgently stir. Be careful not to introduce air bubbles.11.1.2 Prior to the run, a portion of the sample may betransferred to a slab and gently spread out in order to removebubbles, skin, or other debris.NOTE 2Caution: Do
45、not work the sample vigorously; this practicecauses a significant increase in sample temperature. Be sure to close thecontainer immediately after removing the desired portion.12. Conditioning12.1 The temperature of the room (cabinet or collar) shouldbe set at 23 6 1C (or 2C below the reference tempe
46、rature).NOTE 3In accordance with Note 8, the allowable range for specimentemperature is 62C from the reference temperature. However, during thecourse of testing, heat of shearing and body heat of the operator bothcontribute to continuous temperature rises in test specimens, notwith-standing room, ca
47、binet, or collar conditions. To allow for inevitabletemperature rises, temperature controls are set at the lower end of theallowable range.12.2 Equilibration of test samples is not necessary. Speci-men sizes are small (less than 2 mL); when spread out on a slaband applied to the viscometer, both hot
48、 and cold samplesquickly reach the temperature of the metal.12.3 If the viscometer has been idle for more than an hour,it may be necessary to bring it into equilibrium with theconditioning temperature (23C or other specified in 12.1).5The sole source of supply of the certified standard viscosity oil
49、 known to thecommittee at this time is Cannon Instrument Company, P.O. Box 16, State College,PA 16801. If you are aware of alternative suppliers, please provide this informationto ASTM International Headquarters. Your comments will receive careful consid-eration at a meeting of the responsible technical committee,1which you may attend.The Certified Viscosity Reference Standards table in Test Method D 445 showssatisfactory oils including S-600 (16 P at 25C), S-2000 (56 P), S-8000 (230 P), andS-30 000 (810 P). Viscosity at va
