Patent ID: 7608125

Claim:
A method for making a fibrous nonwoven filter media comprising: a) dispersing fibers comprising different types of fibers in a fluid dispersion, b) subjecting the dispersion to a moving forming screen to form a fibrous web, c) optionally applying an aqueous resin binder to the web in sufficient amount to produce a binder level in the filter media of about 18 to about 25 wt. percent, and d) drying the wet web and at least partially curing the resin in the binder to form a resin bound fibrous non woven mat, wherein; i) the mat comprises about 32 to about 40 weight percent polymer fibers, having a deniers from microdeniers up to about 6, and about 36 to about 40 weight percent H glass fibers, based on the total weight of the mat, said filter media also optionally containing up to about 8 wt. percent glass microfibers having a mean diameter of about 3 microns or up to about 12 wt. percent of cellulose pulp fibers; and ii) the aqueous binder comprises a mixture of water and an acrylic latex resin having a glass transition temperature in the range of about 5 to about 30 degrees C. whereby the resultant filter media has a basis weight of about 1.25+/−0.25 lbs./100 sq. ft., a Fraser Air Perm in the range of about 489 to about 643 CFM/sq. ft. and a Taber® stiffness of at least 10, and when the mat is pleated and formed into a pleated gaseous filter using conventional pleating and assembly techniques produces a filter meeting at least MERV 6 specifications and requires no additional means of support in the pleated gaseous filter.