This test 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 conditions of low shear rate. Apparent viscosity as determined by this method may not correlate well with end use applications where high shear rates are encountered.

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 generally 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.

1.1 This test method covers the determination of the apparent viscosity of petroleum waxes compounded with additives (hot melts). It applies to fluid hot melts having apparent viscosities up to about 20 Pas at temperatures up to 175°C (347°F).

For petroleum waxes and their blends having low apparent viscosities, below about 15 mPas, Test Method D 445, is especially applicable.

1.2 The values stated in SI units shall be regarded as the standard. One pascal second (Pas) = 1000 centipoises (cP). One millipascal second (mPas) = 1 centipoise (cgs units).

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.