If microfiber leather wants to replace part of the leather for shoe material, it needs to have excellent moisture permeability and waterproof function, otherwise it will be uncomfortable to wear shoes made of microfiber leather.
So how can microfiber leather for shoes have both moisture permeability and waterproof function? The answer is to do something on the microfiber leather base fabric.
Because moisture permeability is actually two processes of adsorption and transfer, then we need to have water vapor (sweat) adsorption points on the microfiber leather base cloth, so that the water vapor inside the shoe can be adsorbed on the microfiber leather base cloth, and then gradually transferred to the outside of the shoe. So how can the adsorption point adsorb water vapor? It can be done in two ways, both hydrogen bonding adsorption and porous adsorption. Since water vapor can form hydrogen bond with nylon fiber of microfiber leather base cloth more easily, it has certain hydrophilic adsorption performance, so microfiber leather base cloth has certain hydrophilic adsorption performance. Then again, microfiber base cloth generally has more pores, so the larger the surface area is, the more water vapor will be absorbed. After adsorption, the water vapor should be transferred to the outer layer, so the pore size and open pore rate of microfiber leather base cloth determine the speed and total amount of transfer.
Of course, because the pore size of microfiber leather is large and uneven, although it has the function of moisture permeability, rainwater can easily pass through it, which means it cannot reach the function of waterproof. Therefore, special treatment of microfiber leather base fabric is needed to make it also have some hydrophobic property. How is this done? The diameter of water vapor molecule is 4×10-4μm, and the minimum diameter of the micro-pore through which rain and fog can pass is 20μm for fog, 400-900μm for light rain, and more than 2000μm for medium and heavy rain. In layman’s terms, it means that the pore size of microfiber leather base fabric is designed to be between the diameter of water vapor molecules and the diameter of rain and fog perforation, and it can achieve the function of both moisture permeability and waterproof.
To sum up, in the process of producing microfiber leather base fabric for shoes, reasonable design in the pore size and opening rate of the base fabric can make the microfiber leather for shoes have both moisture permeability and waterproof function.
