1.1 This test method covers a procedure used to measure the resistance to bending of papers which are of low grammage, or high flexibility, or both, and which exhibit bending stiffness in the range of 0 to 10 Taber stiffness units.
1.2 This test is used to determine the bending moment required to deflect the free end of a 38 mm (1.5 in.) wide vertically clamped specimen 15° from its center line when the load is applied 10 mm (0.39 in.) away from the clamp. The resistance to bending is calculated from the bending moment.
1.3 The instrument used in this test method is identical to that described in TAPPI T 489 “Bending Resistance (stiffness) of Paper and Paperboard,” used in the modified configuration described in section 6.2.4. Preparation of Apparatus.
1.4 Test results obtained using the Taber-Type Tester as described in this test method have been reported to be as much as 40% different from those obtained using TAPPI T 489, and this test method must not be used where TAPPI T 489 is specified.
1.5 Other procedures for measuring bending resistance include TAPPI T 535 “Stiffness of Paperboard (Resonance Length Method)” and TAPPI T 543 “Bending Resistance (Stiffness) of Paper (Gurley-Type Stiffness Tester).” The latter method has been classified as a Classical Method.