New Softness Evaluation Tissue Softness Analyzer TSA

Abstract

One of the most import characteristics to determine whether a tissue is functional or not is the“softness”. The consumer can directly sense this parameter so that it influences the purchasing behavior decisively. However, the commonly used term”softness”is not correct. The words“handfeel”or“grip”or“haptics”respectively should be used as the softness is only one of several factors that influence the individual evaluation of tissue.
The individual perception of the handfeel is therefore mainly determined by the following characteristics : the actual fiber softness/fiber stiffness (which is determined by the fiber material itself, but also by added chemicals like softeners, wet strength agents or lotion) ; the surface and internal structure, which depend on the manufacturing technology and on the“creping”and“embossing”, if applicable ; and the stiffness, which is mainly determined by the fiber material, the manufacturing technology and the used chemicals. Furthermore, the thickness, the grammage and the number of plies come into play. This makes clear that it is, similar to the evaluation of the taste of wine or whiskey, a very complex and extremely subjective and therefore unreliable parameter. This parameter is further influenced unconsciously by the color, the smell, printed patterns, the tester's current mood and motivation, even the weather and the season as well as personal preferences.
As there were no working physical measuring methods, a so called“handfeel panel”determines the handfeel manually. As the perception of softness or better handfeel of one person is subject to big variations (depending on the mood or motivation of the day, the weather, the season, etc.) the average of the test results of a panel, of at least 10 testers that represent the consumers of the respective market, has to be taken to get a more or less reproducible and representative result. High exactness requirements present very high demands concerning the selection and the training of the members of the panel as well as the mathematic and statistics analysis. Furthermore the testing results of a panel are dependent on testing procedure and the specifics of the area (cultural preferences, climate…) But even if these requirements are fulfilled at best, it is definitely not possible to undercut a certain error margin. Therefor they need objective method to evaluate softness.
Then TSA has been developed. It measures 3 parameters related to softness and can correlate result with hand feel by panel test using algorism.