ASTM D3236 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 apparent 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).
NOTE 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 x 10(6) mPa·s and provides temperatures up to 260 °C (500 °F).
NOTE 2 - For petroleum waxes and their blends having apparent viscosities below 15 mPa·s, Test Method D445 is especially applicable.
NOTE 3 - One pascal second (Pa·s) = 1000 centipoise (cP); one millipascal-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 appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)
3. Terminology
3.1 Definitions:
3.1.1 apparent viscosity - 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 - 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.
