2007, Piran, Slovenia

Clothing
CORRELATION BETWEEN SUBJECTIVE PERCEPTIONS OF
MOIST FABRICS AND THE THERMAL ABSORPTION
COEFFICIENT
Uli Spindler, Manuela Bräuning
W.L. Gore & Associates GmbH, Putzbrunn, Germany
Hochschule Albstadt-Sigmaringen, Albstadt, Germany
Contact person: uspindle@wlgore.com
Base layer wear comfort is influenced by many different factors, and there have been
quite a number of attempts to develop evaluation systems for estimating wearer
comfort from laboratory test, such as the Kawabata system, or the Hohenstein wear
comfort vote for underwear. Although these systems are of great value for the
evaluation of fabrics, we were looking for a method to especially evaluate the effect
of the influence of moisture in clothing layers next to the skin. We believe that the
coolness to touch of the intermittent, short-term contact of a wet fabric has a strong
influence on its comfort and wetness perception, and we think that one of the main
reasons is the skin temperature reduction caused by the touch. Hence, the so called
thermal absorptivity (b = sqrt ( c • ρ • λ)) of a fabric should have a major influence on
the wetness perception. When comparing thermal absorptivity data of usually well
perceived underwear and single jersey cotton in different stages of wetness we could
see a clear difference between the two.
In the current study we investigated, as a first step to evaluating this hypothesis, the
correlation between the thermal absorptivity values a single jersey cotton fabric in
eight different states of wetness, and its affect on subjective comfort perception in a
short-term contact with the skin of the lower arm. Cotton was chosen because it has
the highest water retention of commonly used fabrics. We found a linear correlation
between cold, wetness, and comfort perception with a strong inter-individual
influence.
In the second part of the study, we tested our hypothesis that the fabric itself has
limited influence on these correlations. Four different fabrics samples were tested in
three different thermal absorptivity levels (low, medium, high). That is, each fabric
was wetted such that each had the same thermal absorptivity level, but not the same
moisture content. The fabrics were chosen to reflect quite different properties: the
cotton sample from the first part, a merino underwear, a thick polypropylene cotton
underwear with a strong directional wicking, and a WINDSTOPPER® base layer
laminate also with directional wicking in its polyester skin side fabric.
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