Compressive Strength of an in S-shape Fixed Sample - A New Test for Paper Intended to Use for Corrugated Medium

摘要

The S-test is a new method to characterize flute base papers. Derived from the SCT-test, the procedure is comparable. Therefore, the S-test offers some advantages compared to the common CMT. This new method is less dependent on handling procedure and the test can be enclosed in an automatic paper lab. Compared with other paper and board parameters, the S-test correlates very well with paper grammage and paper thickness. CMT first peak correlates very well, too. Nevertheless, SCTmd correlates less good, although regression analysis still leads to a coefficient of determination of 0.82. Observing CMT end value, the correlation is far less than with CMT first peak. Taking the base paper, manufacturing a corrugated board and measuring the FCT offers a good correlation with the S-test, as long as no fine flutes (D, E or even smaller) are used. Due to the advantage in handling, the test is in the procedure to become a German standard (DIN 5014). On ISO level, in 2019 this test shall be proposed to become a new work item proposal (NWIP). Precision of the test has been determined on four levels to be in the range of 16 % to 26 % concerning repeatability and 23 % to 31 % concerning reproducibility.