The effect of mechanical action on laundering shrinkage of woven fabrics made from cotton, rayon and vinylon fibers was investigated for some situations involving variations in pulsator speed and washing time.
The summary is as follows:
1) Shrinkage of each fabric is determined by the mechanical energy input to the fabrics, evaluated from electric power consumption increase due to the addition of cloths into the washing system, irrespective of pulsator speed or washing time.
2) The process of shrinkage of each fabric can be deviled into three stages, and can be explained as the creep recovery process with the mechanical model composed of one elastic element for the first stage of shrinkage caused by washing without mechanical force and two Voigt elements for the second and third stages of shrinkage caused by washing with mechanical force, connected in series with one another. We suggest an idea of retardation energy as the product of retardation time and power input to the fabrics. All fabrics examined have about the same retardation energies, which are approximately 0.3×10⁴J/kg in the second stage and 19×10⁴J/kg in the third stage.

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