Surface characterization of paper and paperboard using a stylus contact method

Abstract

Surface characterization is important and has many applications in the paper industry. Surface characterization requires both surface roughness and surface friction. The relationship between the two has not been fully established for paper and paperboard. It has been a common practice that only the average property and the standard deviation with the coefficient of variation (COV) are reported for surface roughness and friction measurements. This practice, however, provides few information on surface structure and can lead to wrong judgments because two samples having the same average and the COV can have different physical properties. To avoid such mistake, a new surface characterization method has been developed. To this end, surface roughness- and friction-profiles have been obtained using a latest version of Kawabata surface tester (Model: KES-SESRU, Kato Tech, Kyoto Japan). This new version uses the same stylus for both measuring surface roughness and friction under the same operating conditions. It was found that a correlation between the surface roughness and surface friction was very low. This indicates that they should be independent of each other. Therefore, both should be determined for surface characterization.

Towards Expanding the Use of Paper Made from Recycled and Non-Woody Plants: Enhancing the Print Quality through the Application of Nano-Modified Offset Inks

“…Two different roughness parameters were measured: the parameter R a , which expresses the arithmetic mean deviation of the surface profile, and R z , which defines the vertical distance between the highest peak and deepest valley within the measuring length, according to ISO 21920-2:2021 [39]. Surface profilometry is widely used in the paper industry today as it enables the comparison of the results obtained with the various properties of the paper surface structures, which are important for the interactions within the papermaking and printing processes [40,41]. The size of the stylus was 2 µm and measuring force was 0.00075 N. Ten repetitions were made for each sample and the average values of the results were obtained.…”

Role of blank moisturisation in press forming of paperboard

“…The friction properties of paperboard with different material pairings, such as aluminium and cellulose film (Kawashima et al 2008), metal and rubber (Deshmukh 2005), stainless steel (Ko et al 2020;Lenske et al 2017), or PTFE foil (Lenske et al 2022) have been investigated. A direct comparison of the obtained values is not possible due to differences in measurement procedures, including normal force, and velocity.…”

Characterization of paper surfaces by friction profilometry

“…An interest in a stylus-type contact surface profilometric technique is continuously growing for the paper industry because the technique resembles papermaking processes such as creping, coating, printing, lamination, calendaring, and embossing (Pino et al 2010;Samyn et al 2011;Schlegel et al 2011). It also is similar to the method used for evaluating the quality attributes of paper products such as softness, wettability, printability, and absorption (Ko et al 1981;Hollmark 1983aHollmark , 1983bHodgson and Berg 1988;Ampulski et al 1991;Modaressi and Garnier 2002;Kuilenburg et al 2013;van Wang et al 2018;Ko et al 2020). To this end, the friction component has been recognized as more relevant because the roughness component may not be able to identify the differences in the quality attribute.…”

“…In the stylus-type contact method, a probe (or stylus) scans a sample surface along the predetermined direction to generate a profile of the height variation against the scan length, being referred to as a roughness profile (Jeong et al 2019;Ko et al 2020;Park et al 2021). In this method, stylus shape and size, contact force, and scan speed have been identified as the key variables responsible for generating surface profiles (Kawabata 1980;Yokura et al 2004;Beuther et al 2012;Hanaor et al 2013;Zhai et al 2016;Zhai et al 2017;Jeong et al 2019;Ko et al 2020). In contrast with the roughness-profile, very few works on characterizing the friction component from friction profiles have been available.…”