A method for forming multi-layered fiber including a core, a first layer, and a second layer. The core has an exterior surface portion containing polypropylene. The first layer is applied to at least a portion of the core and contains a first polymer. The first polymer contains a polymer having at least 70% α-olefin units and is characterized by a melting temperature lower than the melting temperature of the exterior surface portion of the core. The second layer is applied to at least a portion of the first layer and contains a second polymer. The second polymer contains a co-polymer having at least 50% α-olefin units and is characterized by a number-average molecular weight of about 7,000 g/mol to 50,000 g/mol, a viscosity of between about 2,500 and 150,000 cP measured at 170° C., and a melting temperature lower than the melting temperature of the exterior surface portion of the core. The viscosity of the second polymer is not greater than about 10 percent of the viscosity of the first polymer measured at 170° C.