Fibrillated fibers for liquid filtration media

Abstract

Fiber webs which are used in filter media are described herein. In some embodiments, the fiber webs include fibrillated fibers and optionally non-fibrillated fibers, amongst other optional components (e.g., binder resin). In some embodiments, the fiber webs include limited amounts of, or no, glass fiber. The respective characteristics and amounts of the fibrillated fibers are selected to impart desirable properties including mechanical properties and filtration properties (e.g., dust holding capacity and efficiency), amongst other benefits.

What is claimed is: 
     
         1 . A filter media comprising:
 a layer comprising:   greater than or equal to 20 wt % and less than or equal to 80 wt % fibrillated fibers; and   greater than 10 wt % and less than or equal to 80 wt % binder fibers,   wherein the layer has a basis weight of greater than or equal to 10 g/m 2  and less than or equal to 200 g/m 2  and a Mullen burst strength of greater than 10 psi.   
     
     
         2 . A filter media comprising:
 a layer comprising:   greater than or equal to 20 wt % and less than or equal to 80 wt % fibrillated fibers; and   greater than 10 wt % and less than or equal to 80 wt % binder fibers,   wherein the layer comprises less than or equal to 20 wt % binder resin and has a tensile strength in the machine direction of greater than 10 N/15 mm.   
     
     
         3 . A filter media comprising:
 a layer comprising:   greater than or equal to 20 wt % and less than or equal to 70 wt % fibrillated fibers; and   greater than or equal to 30 wt % and less than or equal to 80 wt % binder fibers,   wherein the filter media has a dust holding capacity of greater than or equal to 80 g/m 2  and less than or equal to 175 g/m 2 .   
     
     
         4 . The filter media of  claim 1 , where the layer comprises 0 wt % binder resin. 
     
     
         5 . The filter media of  claim 1 , wherein the layer comprises greater than or equal to 30 wt % binder fibers. 
     
     
         6 . The filter media of  claim 1 , wherein the layer comprises greater than or equal to 60 wt % fibrillated fibers. 
     
     
         7 . The filter media of  claim 1 , wherein the fibrillated fibers have an average CSF value of greater than or equal to 10 mL and less than or equal to 300 mL. 
     
     
         8 . The filter media of  claim 1 , wherein the layer has a thickness of less than or equal to 0.6 mm. 
     
     
         9 . The filter media of  claim 1 , wherein the layer has a tensile strength in the machine direction of greater than 10 N/15 mm and/or a mean flow pore size of greater than or equal to 1 micron and less than or equal to 20 microns. 
     
     
         10 . The filter media of  claim 1 , wherein the filter media has a dust holding capacity of greater than or equal to 80 g/m 2  and less than or equal to 175 g/m 2 . 
     
     
         11 . The filter media of  claim 1 , wherein the filter media has an initial efficiency of at least 60% for a particle size of greater than or equal to 4 microns. 
     
     
         12 . The filter media of  claim 1 , further comprising a second layer. 
     
     
         13 . The filter media of  claim 12 , wherein the second layer is directly adjacent the layer. 
     
     
         14 . The filter media of  claim 12 , wherein the second layer comprises synthetic fibers, binder fibers, and/or fibrillated fibers. 
     
     
         15 . The filter media of  claim 12 , wherein the second layer comprises meltblown fibers. 
     
     
         16 . The filter media of  claim 12 , wherein the second layer comprises cellulose and/or synthetic fibers. 
     
     
         17 . The filter media of  claim 12 , wherein the filter media has a dust holding capacity of greater than or equal to 80 g/m 2  and less than or equal to 300 g/m 2 . 
     
     
         18 . The filter media of  claim 12 , wherein the filter media has a thickness of less than or equal to 2 mm. 
     
     
         19 . The filter media of  claim 12 , further comprising a third layer. 
     
     
         20 . The filter media of  claim 15 , further comprising a fourth layer.