FOLDING ENDURANCE – SCHOPPER
Purpose of the test
This test is performed to determine the folding endurance of paper or folding board.
Procedure
Operate the instrument in accordance with ISO 5626 and the manufacturer’s instructions.
Leave the samples exposed for 24 h to 23°C and 50% R.H., according to ISO 187.
Cut two 15,0±0,1 mm wide strips with their long sides parallel to the long side of the sheet, from each of the 20 sheets, edge strips are not to be used.
Make 20 determinations, record the number of double folds and expressed as log10 double folds.
Report 20 measures in log10, their mean and standard deviation calculated to 3 significant figures.
ISO 5626
Nr. of samples
22 test pieces per level
Sample size 60 x 150 mm²
Special size A4
Levels
Level 1: 2.00÷2.50 log10(n D.F.)
Level 2: 2.60÷3.40 log10(n D.F.)
Reporting
Report 20 valid results of measurements in log10, their mean and their standard deviation. All to three significant digits.