ASTM D3236-15(R2021) pdf free download

ASTM D3236-15(R2021) pdf free download.Standard Test Method for Apparent Viscosity of Hot Melt Adhesives and Coating Materials
1. Scope
1.1 This test method covers the determination of the appar- ent viscosity of hot melt adhesives and coating materials compounded with additives and having apparent viscosities up to 200 000 millipascal second (mPa·s) (Note 3) at temperatures up to 175 °C (347 °F). N OTE 1—Although precision has not been studied, this procedure may be adaptable to viscosities higher than the present 200 000 mPa·s limit and temperatures above 175 °C (347 °F). Equipment described in this test method permits testing of materials having viscosities as high as 16 × 10 6 mPa·s and provides temperatures up to 260 °C (500 °F). N OTE 2—For petroleum waxes and their blends having apparent viscosities below 15 mPa·s, Test Method D445 is especially applicable. N OTE 3—One pascal second (Pa·s) = 1000 centipoise (cP); one milli- pascal-second = one centipoise. 1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.4 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Terminology
3.1 Definitions: 3.1.1 apparent viscosity, n—the viscosity determined by this test method and expressed in millipascal seconds. Its value may vary with the spindle and rotational speed selected because many hot melts are non-Newtonian. 3.1.2 viscosity, n—the ratio of shear stress to shear rate. The viscosity of a liquid is a measure of the internal friction of the liquid in motion. The unit of dynamic viscosity is the pascal second. For a Newtonian liquid, the viscosity is constant at all shear rates. For a non-Newtonian liquid, viscosity will vary depending on shear rate.
4. Summary of Test Method
4.1 A representative sample of the molten material to be tested is maintained in a thermally controlled sample chamber. Apparent viscosity is determined under temperature equilib- rium conditions using a precision rotating spindle type viscom- eter. Data obtained at several temperatures can be plotted on appropriate semi-logarithmic graph paper and apparent viscos- ity at intermediate temperatures can be estimated.
5. Significance and Use
5.1 This test method distinguishes between hot melts having different apparent viscosities. It is believed that apparent viscosity determined by this procedure is related to flow performance in application machinery operating under condi- tions of low shear rate. Apparent viscosity as determined by this test method may not correlate well with end-use applica- tions where high shear rates are encountered. 5.2 Materials of the type described in this procedure may be quite non-Newtonian and as such, the apparent viscosity will be a function of shear rate under the conditions of test. Although the viscometer described in this test method gener- ally operates under conditions of relatively low shear rate, differences in shear effect can exist depending upon the spindle and rotational speed conditions selected for the test program. Maximum correlation between laboratories, therefore, depends upon testing under conditions of equivalent shear.
6. Apparatus
6.1 Viscometer, Concentric Cylinder Rotational—The es- sential instrumentation required providing the minimum ratio- nal viscometer analytical capabilities include: 6.1.1 Drive motor, to apply a unidirectional rotational dis- placement to the specimen at a rate of 0.5 r⁄min to 60 r⁄min constant to 61 %. 6.1.2 Force sensor, to measure the torque developed by the specimen in response to the rotational displacement. 6.1.3 Coupling shaft, or other means to transmit the rota- tional displacement from the motor to the specimen. N OTE 4—It is helpful to have a mark on the shaft to indicate appropriate test fluid level. 6.1.4 Stainless steel rotational element, spindle, or tool, for the type shown in Fig. 1 to fix the specimen between the draft shaft and a stationary position. 6.1.5 Data collection device, to provide a means of acquiring, storing, and displaying measured or calculated signals, or both. The minimum output signals required for rotational viscometry are torque, rotational speed, temperature, and time.