1.1 This method determinesthe coefficient of static friction of most packaging materials by measuring the angle at which one test surface begins to slide against another inclined surface as the incline is increased at a constant and prescribed rate.
1.2 The test is frequently referred to as slide angle. The coefficient of friction is numerically equivalent to the tangent of the angle when the test surface begins to slide.
1.3 TAPPI T 549 describes a horizontal method for determining static and kinetic friction but is intended for application to printing and writing papers and the procedures are somewhat different.