Method of making a thin filtration media

A method of making a filtration media, comprising the steps of:

• forming a fiber furnish having a fiber composition of 80-100 wt % cellulose fibers and 0-20 wt % synthetic fibers, the cellulose fibers comprising at least 50 wt % curled softwood pulp of a type that a 60 pounds per 3,000 square feet (98 g/m2) handsheet made exclusively from the curled softwood pulp has a caliper of 16-26 mils (0.41-0.66 mm), and an air permeability of 100-175 cfm (508-8891/m2s);
• diluting the fiber furnish;
• refining the fiber furnish to induce fibrillation of the softwood fibers;
• forming a fiber web on a paper machine from the fiber furnish;
• drying the wet web to form a dry sheet;
• applying a resin binder to the dry sheet to form a saturated sheet;
• and
• curing the resin in the saturated sheet to form a cured sheet having a wet Mullen ratio of 20% to 90%, a caliper of about 6 to 15 mils (0.15 to 0.38 mm), and an air permeability of at least 20 cfm (101.61/m2s).