Thermal comfort levels and abrasion resistance of protective denim motorcycle clothing
In the last twenty years there has been an emergence of a new class of motorcycle apparel, often referred to as protective denim. Its construction is a denim outer fabric with an inner protective liner fabric made from high performance fibres such as those made from aramids, ultra high molecular weight polyethylene (PE) and aromatic polyester liquid crystal polymer (LCP). These garments should have suitable thermal comfort levels off the bike while providing a high level of abrasion protection to be successfully adopted by riders.
This work used a thermal sweating hotplate and a CE standard impact abrasion test method to evaluate a number of protective denim products. It analysed the thermal resistance of the product in both dry and wet (sweating) modes and compared them with their resistance to abrasion. It compared the four main protective layer types used in protective denim; a woven aramid, a double jersey knitted aramid, a terry loop knitted aramid/PE and a rib knitted LCP. The last two of these products displayed EN 13595-1 level 2 protection labels whereas the remainder had no manufacturer specified abrasion resistance.
The mass per unit area of fabric between the skin and the abrasion surface was directly proportional to abrasion resistance. The woven and double jersey products failed to reach the EN 13595-1 level 1 abrasion resistance but were closer to denim in thermal comfort due to their thinness. The terry loop knit fabric performed far better than the rib knit LCP fabric in both abrasion and thermal comfort. The poor thermal performance of the LCP product was due to the complex spacer fabric arrangement employed around the protective liner.