A study of friction mechanisms between a surrogate skin (Lorica soft) and nonwoven fabrics

Abstract

Hygiene products such as incontinence pads bring nonwoven fabrics into contact with users' skin, which can cause damage in various ways, including the nonwoven abrading the skin by friction. The aim of the work described here was to develop and use methods for understanding the origin of friction between nonwoven fabrics and skin by relating measured normal and friction forces to the nature and area of the contact (fibre footprint) between them. The method development work reported here used a skin surrogate (Lorica Soft) in place of skin for reproducibility. The work was primarily experimental in nature, and involved two separate approaches. In the first, a microscope with a shallow depth of field was used to determine the length of nonwoven fibre in contact with a facing surface as a function of pressure, from which the contact area could be inferred; and, in the second, friction between chosen nonwoven fabrics and Lorica Soft was measured at a variety of anatomically relevant pressures (0.25-32.1kPa) and speeds (0.05-5mms(-1)). Both techniques were extensively validated, and showed reproducibility of about 5% in length and force, respectively. Straightforward inspection of the data for Lorica Soft against the nonwovens showed that Amontons' law (with respect to load) was obeyed to high precision (R(2)>0.999 in all cases), though there was the suggestion of sub-linearity at low loads. More detailed consideration of the friction traces suggested that two different friction mechanisms are important, and comparison with the contact data suggests tentatively that they may correspond to adhesion between two different populations of contacts, one "rough" and one "smooth". This additional insight is a good illustration of how these techniques may prove valuable in studying other, similar interfaces. In particular, they could be used to investigate interfaces between nonwovens and skin, which was the primary motivation for developing them.

Microscopic contact area and friction between medical textiles and skin

“…This skin model was found to realistically simulate the friction of dry human skin in contact with textiles (Derler et al, 2007;Gerhardt et al, 2008) and was recently applied to study the friction of a functional medical textile (Gerhardt et al, 2013) as well as nonwoven fabrics (Cottenden and Cottenden, 2013).…”

“…3 illustrates that the surface of Lorica soft has a considerably smoother surface than the investigated textiles. Cottenden and Cottenden (2013) stated that despite irregularities and deviations such as fine lines and wrinkles, the surface of Lorica soft can be reasonably approximated as a plane.…”

Development of an Innovative Product from Plasma Treated Cotton Fabrics to Manage Incontinence

“…On the subject of incontinence, there is a plethora of literature available, Sabrina [5] conducted an extensive study on the non woven fabrics particularly on their frictional properties. Although friction is considered to be an important property, other properties such as breathability thermal insulation and moisture vapour transmission are important Cottendon and Cottendon and Asimakopoulos [6] have dealt with the friction between non woven fabrics and skin. If some material like woven cotton is stitched with a nonwoven fabric pad inside to provide absorption, it will be an ideal product to manage incontinence.…”

Comparison of the Friction Behavior of Occluded Human Skin and Synthetic Skin in Dry and Moist Conditions

“…Many materials have been used in attempts to simulate the tribological behaviour of human skin in various conditions and against various materials [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Many of these studies have concerned the friction of skin against fabrics and textiles, often for the purpose of studying skin blistering and decubitus, or the study of cosmetics applied to the skin.…”