Patent ID: 8133537
Filing Date: 2012-03-13
Classification: B32B,D01F,D06M,Y10T

Abstract:
1. A method of forming a multi-layered fiber comprising: a) forming an elongated core having an exterior surface comprising polypropylene; b) applying a first layer to at least a portion of the core, wherein the first layer comprises a first polymer, wherein the first polymer comprises a polymer having at least 70% α-olefin units and is characterized by a melting temperature less than the melting temperature of the exterior surface of the core; c) applying a second layer to at least a portion of the first layer, wherein the second layer comprises a second polymer, wherein the second polymer comprises 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., wherein the viscosity of the second polymer is not greater than about 10 percent of the viscosity of the first polymer measured at 170° C., and has a melting temperature lower than the melting temperature of the exterior surface of the core wherein the percentage by weight of the second polymer to the total weight of the fiber is between about 0.25% wt and 50% wt.