Journal Published Online: 12 June 2015
Volume 43, Issue 6

Effect of Hardness and Surface Roughness on Slip Resistance of Rubber



Slip resistance is now considered a primary property for footwear. Continuous attempts are being made to design the footwear with suitable materials to provide sufficient grip under the foot at workplaces, on pedestrian pathways, and in the home to reduce slip, trip, and fall accidents. In footwear, the type of sole used, along with the bottom profile, made with the correct design of cleats and drain channel, is greatly influencing slip resistance. In this study, the influence of shore hardness and surface roughness of rubber soling material on slip resistance under dry, wet, detergent, and oil-floor conditions were made at five different slip speeds. The instrument used for this entire study was dynamic slip-resistance test equipment (SATRA Model, STM 603). The overall friction coefficient is caused by the boundary lubrication effect, as the dilute fluids do not have a significant effect on hysteresis, but do affect the adhesion component. This trend of coefficient of friction (COF) is observed in all flooring conditions. Increasing the sliding speed decreases the COF for all four flooring conditions. In the dry flooring condition, the COF is ~1.0 for sole hardness between 65 and 75, and the COF is about 0.50 for shore hardness above 85. Rubber soles with a surface roughness of 221.19 root mean square (rms) (nm) registers a COF of 1.0, whereas soles having a surface roughness of 37.37 rms (nm) registers a COF of ~0.50. For rubber sole material with less hardness, reduction of the COF for dry and wet condition is ~7 %, for detergent contaminants, the reduction is about 30 %, and, for the oil-floor condition, the reduction is 88 %. There is a marked reduction in COF when tested with different sliding speeds; the difference for dry and wet tests is ~7 %–8 % when increasing the speed from 0.1 m/s to 0.5 m/s. But this difference is found to be 10 % for detergent solution and 28 % for oil.

Author Information

Mohan, Ranganathan
Footwear Testing Laboratory, Shoe Design and Development Centre, Council of Scientific and Industrial Research-Central Leather Research Institute (CSIR-CLRI), Adyar, Chennai, IN
Das, Bhabendra Nath
Leather Product Cluster, CSIR - Central Leather Research Institute (CLRI), Honorary Faculty, Anna University, Adyar, Chennai, IN
Sundaresan, Raja
Footwear Testing Laboratory, Shoe Design and Development Centre, Council of Scientific and Industrial Research - Central Leather Research Institute (CSIR-CLRI), Adyar, Chennai, IN
Pages: 13
Price: $25.00
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Stock #: JTE20140249
ISSN: 0090-3973
DOI: 10.1520/JTE20140249