Objective comparison of the softness of Australian Soft Rolling Skin wool and ordinary Merino wool

Abstract

Australian Merino wool is well-known in the wool market for its top quality, and the bulk of it is used in apparel where softness is a key factor for consumers. However, the ethical issue of mulesing is driving textile manufacturers and retailers to purchase non-mulesed wool from other sources instead of Australian mulesed wool. Australian Soft Rolling Skin (SRS) wool, grown on non-mulesed sheep, has been perceived to have a softer handle than ordinary Merino (OM) of the same diameter. In this research, three different methods were deployed to objectively compare the softness of SRS and OM wool. The force required to pull a bundle of clean wool through a series of parallel pins, that is, the pulling force, was used to evaluate the combined effect of fiber bending rigidity and surface friction. SRS wool resulted in lower pulling force than OM wool, with a difference of 15 cN/ktex (approximately 12.5%). According to the Resistance to Compression test results, SRS wool (4.5–5.7 kPa) was easier to compress than OM wool (5.4–6.5 kPa). The modified Resistance to Compression method showed different compression profiles for the two types of wool, and the slope of the decreasing curve (SDC) was used to study the softness property, with lower SDC values representing softer handle. These results confirm that over a fixed diameter range the SRS wool was more compressible and flexible, and this should result in a softer handle for clothing made from the fiber.