Patent ID: 8147957

Claim:
A consolidated fibrous structure comprising at least three (3) fibrous layers, wherein each fibrous layer comprises fibers, wherein the fibers comprise: a core having an exterior surface portion comprising polypropylene; a first layer disposed on at least a portion of the core comprising a first polymer, wherein the first polymer comprises 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; and, a second layer disposed on at least a portion of the first layer, the second layer comprising 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 a melting temperature lower than the melting temperature of the exterior surface portion of the core; wherein at least a portion of the second layers of the fibers in each fibrous layer are fused to at least a portion of other first or second layers of the fibers within the same fibrous layer, at least a portion of the second layers of the fibers of each fibrous layer are fused with at least a portion of the first or second layers of the fibers in an adjacent fibrous layer, and the stiffness of the consolidated fibrous structure is at least 1 N-m measured by ASTM D 790.