2-Point Flexure Test on Paper
ISO 2493-1, DIN 5312, ISO 5628, DIN 55437-3iso 2493-1
ISO 2493 consists of the following parts, under the general title Paper and board — Determination of bending resistance:
- — Part 1: Constant rate of deflection
- — Part 2: Taber-type tester
In ISO 2493:1992, two principles for determining the bending resistance were incorporated in the same standard, although the two principles were very different.
One principle involved the deflection of an equal number of test pieces with opposing surfaces towards the direction of deflection; this principle is described in this part of ISO 2493.
The other principle used a Taber-type tester, where the test piece was inserted and deflected to the top side and then, without changing the test piece, it was deflected in the opposite direction. This principle is described in ISO 2493-2. The method is based on TAPPI Test Method T 489 om-04
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 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.