This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. Designation: D2556 5-14 (Reapproved 2018) T INTERNATIONAL Standard Test Method for Apparent Viscosity of Adhesives Having Shear-Rate- Dependent Flow Properties Using Rotational Viscometry1 This standard is issued under the fixed designation D2556; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval. This standard has been approved for use by agencies of the U.S. Department of Defense. 1. Scope 3.1.3 non-Newtonian behavior, n-the property of a liquid 1.1 This test method covers the measurement of the appar- in which its viscosity is not constant over a stated range of ent viscosity of shear-rate-dependent adhesives using a rota- strain rates. tional viscometer. 3.2 Def nitions of Terms Specif c to This Standard: 1.2 The values stated in SI units are to be regarded as 3.2.1 apparent viscosity, n-resistance to shear at a given standard. No other units of measurement are included in this rate of shear, expressed as viscosity in mPa's. standard. NorE 1—The SI unit of mPa's is equivalent to cP 1.3 This standard does not purport to address all of the 3.2.2 thixotropic index, n-the ratio of apparent viscosities safety concerns, if any, associated with its use. It is the at two rotational speeds. responsibilityoftheuserofthisstandardtoestablishappro priatesafety,health,andenvironmentalpracticesanddeter 4. Signif cance and Use mine the applicability of regulatory limitations prior to use. 4.1Theprincipleofmeasurement is basedupona reversible 1.4 This international standard was developed in accor- isothermal change in apparent viscosity with change in rate of dancewithinternationallyrecognizedprinciplesonstandard- shear produced by a change in rotational speed. ization established in the Decision on Principles for the DevelopmentofInternationa/Standards,GuidesandRecom- 4.2Measurement is performed with a rotational viscometer mendations issued by the World Trade Organization Technical under standardized conditions with rigid control of thetime BarrierstoTrade(TBT)Committee. intervals of measurement.Viscosity readings are obtained at the end of 1 min for each rotational speed. Changes from the 2. Referenced Documents lowest speed to the highest speed, and return to the lowest speed, are made without stopping the instrument. 2.1 ASTM Standards.2 D907 Terminology of Adhesives 5. Apparatus 3.Terminology 5.1 Rotational ViscometerThe essential instrumentation required providing the minimum rotational viscometer analyti- 3.1Defnitions. cal capabilities include: 3.1.1Many terms in this test method are defined in Termi- 5.1.1 A drive motor, to apply a unidirection rotational nologyD907 displacement to the specimen at a rate of 0.2 revolutions per 3.1.2 Newtonian behavior, nthe property of a liquid in minute to 60 rev/min constant to within 61%. which its viscosity is constant over a stated range of strain 5.1.2 A force sensorto measure the torque developed by the rates.(Comparenon-Newtonianbehavior) specimen to within 61%. 5.1.3Acouplingshaftorothermeanstotransmitthe rotationaldisplacementfromthemotortothespecimen This test method is under the jurisdiction of ASTM Committee D14 on Adhesives and is the direct responsibility of Subcommittee D14.10 on Working 5.1.4Aspindle,geometry,tool,orrotationalelementtofix Properties. the specimen between the driveshaft and a stationaryposition Current edition approved Nov. 1, 2018. Published November 2018. Originally approved in 1966. Last previous edit