b'CREPING PROCESS EFFICIENCIESselection ofLab selection of the proper adhesive the properfor a given creping moisture can adhesiveonly be achieved via testing of the can only beadhesive films at the operating achieved viatemperatures for that creping testing ofmoisture. This is accomplished via the adhesiveheated platins on tack tester units films at theand creping sled apparatus.operating temperaturesCREPING POCKET ANGLEfor thatThe creping pocket angle is defined Figure 2. Burstcrepingas the angle between the creping strength of papermoisture.blade shelf and the tangent to vs ambient relativethe Yankee surface at the point of humidity.contact of the blade. This angle is the result of the application angle, blade bevel, and deflection of the blade. Figure 3 shows the relationship of angles for a theoretical, non-flexing blade. Tissue makers generally adjust the angle by switching out blades of varying bevel angles in order to achieve the desired creping pocket angle. This is done because opening and closing the pocket impacts the ratio of micro crepe to macro crepe. Typical LDC creping pocket angles range from as closed as 74 degrees for some towel, napkin and Figure 3. Creping geometry (4). commercial bath to as open as 100 degrees for high quality facial.The prevalent description in the industry for micro and macro crepe formation is summarized by Raunio and Ritala 6.However, this theoretical model only considers geometric or shaped bulk 7. This process is related to column failure mechanics, whereby the increasingly uniform adhesion results Figure 4. Creping process and the formation of micro-folds and macro-folds as a function of thein explosive de-densification as creping pocket angle. Left: small angle. Right: large angle 6. explained by Dr. Wes McConnell:24 TISSUE TECHNOLOGY INTERNATIONAL'