1 Scope
This part of ISO 2493 specifies procedures, based on the two-point loading principle, for determining the bending resistance of paper and board.
NOTE 1 See ISO 5628[1] for a detailed description of the two-point loading principle.
This part of ISO 2493 applies to the measurement of the bending resistance within the range 20 mN to 10 000 mN. It is not applicable to corrugated board but can be applicable to the components of such board.
The bending angle is 15° and the bending length is 50 mm.
For samples having a bending resistance that is too low to measure with a bending length of 50 mm, a shorter bending length, i.e. 10 mm, can be used.
IMPORTANT — The results obtained when using different bending lengths will not be comparable.
For boards that tend to be permanently deformed if bent through 15°, the half bending angle, i.e. 7,5°, can be used.
NOTE 2 Taber-type testers and testers using the principle of constant rate of deflection do not give comparable results. For this reason, ISO 2493:1992 has been divided into two parts.