Bending resistance of paper relates to a number of end-use applications including wrapping, printing, copy machine performance, high-speed mechanical handling of documents, and other applications.

1.1 This test method covers a procedure used to measure the resistance to bending of paper and paperboard.

1.2 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 50 mm (1.97 in.) away from the clamp is determined. The resistance to bending is calculated from the bending moment.

1.3 Some instruments of the type described in this test method (see Section 6) may be equipped with ultrasensitive attachments or may be modified to accommodate shorter specimen lengths than that specified in this test method (see Section 9).

1.4 Test Method D 5650 describes a modification of the instrument described in this test method for measurements in the 0 to 10 Taber stiffness range only, and which requires a smaller test specimen. The modified procedure may be recommended for papers which are low in grammage or highly flexible, or both.

1.5 Test results obtained using modifications of the basic Taber-type instrument such as that described in Test Method D 5650 have been reported to be as much as 40 % different from those obtained using this test method, and such modifications must not be used when this test method is specified.

1.6 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.