Characteristic Test（Surface Characteristic）
Surface characteristic are investigated by performing smoothness tests where the sheet surface and the standard plane, which is smoothly polished, are measured at a constant contact pressure, as well as a surface strength test (picking) using wax.
This is a test for investigating the smoothness of sheets. Smoothness is expressed in the transit time of 10 cc of air flowing through a gap when the sheet surface is brought into contact with the standard plane, which is smoothly polished, at a constant contact pressure. The longer the transit time, the higher the smoothness.
Picking (wax surface strength test)
This is a test for investigating the surface strength of sheets. In this test, the tips of 20 types of wax sticks with different adhesive force are melted and immediately bonded to the test piece surface. After cooling and hardening (left for 15 minutes), the wax sticks are taken off perpendicular to the test piece. Surface strength is expressed by the wax number on the boundary that does not cause swollenness, breakage, and paper peeling.