ISO 22843-2020 pdf download.Rubber bands – General requirements and test methods.
6.2.3 For cut-width, the measurements shall be made at four approximately equally spaced positions around the ring. Measure the cut-with to the nearest of 0,1 mm using suitable measuring devices e.g. vernier caliper, calibrated tape and magnifying microscope. The average value of each set of measurements shall be recorded.
6.2.4 For thickness, the measurements shall be made at four approximately equally spaced positions around the ring. Measure the thickness to the nearest of 0,01 mm using a thickness gauge. The average value of each set of measurements shall be recorded.
In some cases, the rubber bands can be cut or stacked before measuring the thickness. Other suitable measuring devices, e.g. magnifying microscope and force gauge, can be employed providing that their accuracy are appropriate.
6.3 Tensile properties
Where test pieces are required, they may be taken from an uncut tube shape sample (tube sample) or a finish product (ring sample). The tube sample is cut to dumb-bell-shaped type 1A or type 2 whilst the ring sample is used as it is.
Dumb-bell and ring test pieces do not necessarily give the same values for their respective tensile properties. The results obtained for a sample are likely to vary according to the type of test pieces used as well as the different formulations. Therefore, in case of dispute, the dumb-bell test piece shall be used for the referee test.
6.3.1 Test method A: Tube sample
Tensile properties shall be measured in accordance with ISO 37 using dumb-bell type 1A or type 2 test pieces. A dumb-bell test piece shall be cut across the direction of extrusion of uncut tubes (see Figure 3). A minimum of three test specimens shall be taken and the median value shall be reported. In case of dispute, dumb-bell type 2 is the preferred test method.ISO 22843 pdf download.