Wet laid, nonwoven, fibrous mats suitable for making MERV 6 or higher,
filters, and methods of making the nonwoven mats filter media are
disclosed. The mats include a blend comprising a major portion of glass
fibers, a minor portion of man-made polymer fibers, such as polyester
fibers and about 0-30 wt. percent of chemically cross linked bleached
Kraft pulp the fibers, and optionally fully bleached softwood Kraft pulp,
the fibers being bound together with a cured binder having a Tg in the
range of about minus 30 to about 50 degrees C. The mats are pleated prior
to assembling the filter in conventional manner. The only fibrous mat in
the filters is wet laid fibrous nonwoven mat and the pleated filter media
needs no other means of support in the filter frame.