The Influence of Applied Forces on the Felting of Wool

An apparatus and a method have been evolved for measuring the felting shrinkage of yarns at different force values, with good reproducibility. The course of the shrinkage with reference to time in a specific experiment can be satisfactorily defined by means of two parameters-viz., the initial shrinkage rate and the final limit of the shrinkage. The effect of the shaking force on the shrinkage appears to be very important; shrinkage does not occur below a certain value of the forces. Measurements on twisted yarns show that this limit shifts to higher force values when the twist increases; the further course shows that with greater twist the increase in the shrinkage versus force proceeds more slowly. The results obtained may contribute towards the understanding of the shrinkage mechanism, with reference to external conditions and fiber properties.