The Felting Factor of Wool Fiber as a Teaching Material

Abstract

  As a topic in home economics, investigations of the characteristics of wool fibers are important. In this study, the factors that affect the felting of wool were examined.

  An evaluation of felting was carried out using the Aachen felt ball method. It was found that the diameter of the felt balls produced in the test decreased with increasing surfactant concentration, and was smallest at the critical micelle concentration. When wool was treated with a 0.3％ sodium dodecyl sulfate solution, its diameter was reduced by about 20％. In the pH range from 3.0 to 11.5, no significant influence of pH was observed. With a mechanical force of amplitude 3 mm, the diameter of the felt ball was reduced with an increase in amplitude. For an amplitude speed of 2,000 rpm, the diameter of the felt ball was about 20％ lower than that for an amplitude at 500 rpm. Increasing the temperature was also effective in reducing the felt ball diameter; the diameter at 50℃ was about 10％ less than that at 10℃. No significant influence of humidity was observed in the presence of sodium dodecyl sulfate.

  Thus, the most important factors influencing felting were the surfactant concentration, mechanical force and temperature. In consideration of teaching materials, for the experimental setup used in the present study, the optimal conditions were found to be a 0.3％ sodium dodecyl sulfate solution, a temperature of 40℃, and an amplitude speed of 1,500 rpm.