Patent ID: 7462259

Claim:
A method of making a permeable fibrous facer mat on a wet process mat machine in which an aqueous slurry containing fibers, the majority of fibers being glass fibers having a length of at least about 6 mm and an average diameter of at least about 13 microns, is continuously deposited onto the top surface of a moving permeable forming belt, is partially dewatered to form a wet fibrous web, is saturated with an aqueous binder, is again partially dewatered to form a wet, bindered web and is dried to produce a dry non-woven fibrous mat, the improvement comprising making a facer mat having improved flexibility and less irritable handling characteristics by applying a foam or froth, having a blow ratio of at least 15 and being extremely non-draining such that when one liter of the foam is placed in an Imhoff cone and allowed to set for 16 hours, the amount of liquid formed in the bottom of the Imhoff cone is less than about 5 milliliters, onto a top face of the wet, bindered web, the foam or froth having a high percentage of air, and applying said foam at a rate to produce a dry mat having a continuous coating, amounting to about 3-15 grams per square meter of mat, on one face and drying the mat in a manner to break or collapse bubbles in the foam to increase the air permeability of the mat to at least about 150 cubic feet per minute per square foot of mat and to produce a fibrous nonwoven mat having a coating on one surface.