Cross-linked polyethylene fiber, its use and process for its manufacture

Heat-sealable filter paper comprising a mixture of polymer fibers in an amount from about 15 to about 40 weight percent based on the total weight of the heat-sealable filter paper, wherein the mixture of polymer fibers comprises a crosslinked polyethylene fiber and a second polymer fiber having melt-flow index (MFI) below 5, wherein the crosslinked polyethylene fiber is obtained by melt-spinning of a polyethylene polymer having a MFI of above 120 g/10 min to about 400 g/10 min, wherein subsequent to the melt-spinning step the fiber is treated with ionizing radiation to obtain a crosslinked polyethylene polymer fiber, wherein the polyethylene polymer is a polyethylene homopolymer, a polyethylene copolymer, polymer blend comprising polyethylene as one polymer, or a mixture thereof, wherein the crosslinked polyethylene polymer fiber has a MFI of about 1 to about 80 g/10 min.