The frictional properties between human skin and fabrics, films and a KES-SE abradant for friction measurement have been measured by using a surface friction tester, an improved version of the KES-SE friction feeling tester previously described in the Part 1. The author has examined the relations between the stratum corneum water content and the hardness of skin. The MIU of fabrics and films have also been measured with the human skin and the KES-SE abradant for friction measurement. In addition, the effect of the human skin and abradants on MMD and stick-slip phenomenonhas also been examined.
The following results were obtained:
1) A particular attention has been paid for the difference in individual's MIU. The value of MIU is high with increased stratum corneum water content and low with decreased stratum corneum water content, depending on the season and the application of moisturizer. The test results have clearly shown that main factor on the MMD, the variance of coefficient of friction, is the stick-slip of the human skin.
2) The mean coefficient of friction, MIU, of the human skin has reversely increased with decreased hardness of the human skin (measured with a Durometer) . Accordingly, in addition to stratum corneum water content, the hardness of the human skin is another factor on the MIU.
3) The MIU of fabrics determined with the human skin is higher than those of determined with an abradant of KES-SE. A significant difference and a straight regression line have been found between both MIUs. A regression coefficient depends on the stratum corneum water content of individuals according to the seasons. In addition, the MIU of films on the human skin differs from that of fabrics.
4) The possibility of the stick-slips depends on abradants. The stick-slips tend to occur on fabrics where the construction of a fabric weave is regular and periodic to the frictional direction. The stick-slips also tend to occur on nylon 6 and polyester films.
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