Characterization of paper surfaces by friction profilometry

Abstract

Friction profilometry is a powerful technique that is suitable for the surface characterization of paper products. In this technique, a stylus-type contact method that resembles papermaking processes is used for evaluating the quality attributes of products. The surface characterization requires both surface roughness and friction measurements. At present, however, few reports have been available regarding characterization of the friction by the surface profilometric method. The objective of this study was to provide guiding principles of a stylus-type contact surface profilometry for determining the friction properties of paper. Another objective was to introduce the concept of the mean absolute deviation (MAD) from the average coefficient of friction as a new friction parameter.

Surface characterization of paper products by profilometry with a fractal dimension analysis

“…Surface profilometry is a technique to quantify the surface profiles of products. An interest in a stylus-type contact surface profilometric technique is growing in the paper industry because the technique resembles papermaking processes such as creping, coating, printing, lamination, calendaring, and embossing (Park et al 2021;Moon et al 2022). It is also similar to the method used for evaluating the quality attributes such as softness, wettability, printability, and absorption (Hollmark 1983a,b;Ampulski et al 1991;Yokura et al 2004;Ko et al 2018Ko et al , 2020 As a surface profilometer, the KES-SE surface tester (Kato Tech Company (Kyoto, Japan) has been used to measure either roughness or friction of nonwovens, textiles, and tissue and paper products (Kato Tech 2018a,b).…”

“…However, it has been realized that this stylus does not work well on high-density paper such as writing & printing papers, kraft paper, and newsprint (Jeong et al 2019;Moon et al 2022). For these products, a design of a new stylus has been necessary.…”

“…This allows one to examine the relationship between the two properties without ambiguity because the two profiles are generated at the exact same positions (Ko et al , 2020. In this stylus-type contact method, a stylus' shape and size, its contact force on the sample surface, and its scan speed have been identified as the key variables responsible for generating surface profiles (Kawabata 1980;Jeong et al 2019;Ko et al 2020;Moon et al 2022).…”

“…Once the surface profiles are obtained, typical parameters such as the roughness average (Ra) and the average coefficient of friction (μ) can be determined. The absolute mean deviation from the average, that is, R-MAD for the roughness, and F-MAD for the friction, have been suggested as new surface parameters (Ko et al 2020;Park et al 2021;Moon et al 2022). F-MAD has been accepted as an ISO Standard for determining the friction properties of tissue products (ISO 12625-18 2022).…”

“…It seems that fractal geometry should be the rule rather than the exception (Ko et al 2015). Yet very few studies have been available for applying fractal dimension analysis techniques to quantify the surface profiles of paper products (Ko et al 2015;Jeong et al 2019;Moon et al 2022).…”