Gogore It is d responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Density Redefined Anton Paar has once again redefined digital density measurement with the groundbreaking invention of a new measuring principle: The listed specifications apply to a typical instrument with spring mechanics and a classic cylinder or disc spindle in a large sample vessel. Historical Version s — view previous versions of standard. The viscosity behavior measured after high shear is indicative of the characteristics of the paint soon after application.
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A number in parentheses indicates the year of last reapproval. This standard has been approved for use by agencies of the U. Department of Defense. The values given in parentheses are for informationonly.
It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use. Summary of Test Method2. The agitation of the materialimmediately preceding the viscosity measurements is carefullycontrolled.
Significance and Use3. The degree of thixotropy is indicated by comparison ofviscosities at increasing and decreasing rotational speeds TestMethod B , viscosity recovery Test Method B , or viscositiesbefore and after high shear combination of Test Methods Band C.
The high-shear treatment in Test Method C approxi-mates shearing during paint application. The viscosity behaviormeasured after high shear is indicative of the characteristics ofthe paint soon after application. The protective bracket, which attachesto the viscometer and protects the spindle, provides thestationary surface described in the preceding sentence. Setthe viscometer at the slowest rotational speed chosen for thetest Note 8. Initiate the spindle rotation and record thereading after ten revolutions or other agreed-upon number ofrevolutions.
NOTE 9—A higher initial rotational speed may be used upon agreementbetween producer and user. After an observationhas been made at the top speed, decrease the rotational speedin steps to the slowest speed, recording the reading after tenrevolutions or equivalent time at each speed.
At the end of the rest period, start the spindle rotation at theslowest speed and record the reading after ten revolutions orother agreed-upon number of revolutions. Calculations and Interpretation of Results If using a dial reading viscometer,calculate the equivalent viscosity value for each torque value asshown in Section Typical speedcombinations are 0. The resultantviscosity ratio is an index of the degree of shear thinning overthat range of rotational speed with higher ratios indicatinggreater shear thinning.
Such plots may be used formaking comparisons between paints or other materials. Note that both readings were takenat the same rotational speed. The higher the ratio, the greaterthe thixotropy. The higher the ratio, the greater the thixotropy. Precision and Bias It has not been possible to devisea method for determining precision for viscosities at increasingand decreasing speeds other than as individual measurements. No attempt was made to determine the precision of themeasurement of the degree of thixotropy because this param-eter is dependent on the material, the time of the test, and othervariables.
Preparation of Specimen NOTE 10—Materials may be sheared at other speeds using other sizeblades upon agreement between producer and user. Record the scale reading after tenrevolutions or other agreed-upon number of revolutions. The measured viscositybehavior after shearing is essentially that of the paint immedi-ately after application disregarding changes in solids. The viscosity at the lowest speed before-shearing istaken from Test Method B, The viscosity at lowest speed after-shear is taken from Noattempt has been made to determine the precision of the shearthinning index or degree of thixotropy for Test Method C forthe reasons given in Summary of Precision Measurements at increas-ing speeds of 0.
The within-laboratory coefficient of variation for Test Method A singlespeed was found to be 2. The correspondingbetween-laboratories coefficients are 7. NOTE 11—Measurements made by digital apparatus from the samesupplier or apparatus from other suppliers may have different precision 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 be 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 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.
Document Center Inc. The values given in parentheses are for information only. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Significance and Use Test Method A is used for determining the apparent viscosity at a given rotational speed, although viscosities at two or more speeds give better characterization of a non-Newtonian material than does a single viscosity measurement. With Test Methods B and C, the extent of shear thinning is indicated by the drop in viscosity with increasing viscometer speed.