Patent ID: 7285183
Filing Date: 2007-10-23
Classification: B32B,D21F,D21H,Y10T

Abstract:
1. In a method of making a permeable fibrous mat on a wet process mat machine in which an aqueous slurry containing glass fibers is continuously deposited onto the top surface of a moving permeable forming belt, is partially dewatered, and followed by applying an aqueous binder to the wet web and again is partially dewatered by passing the wet web over a suction box to reduce the binder content to a desired level, and followed by drying the wet web to produce a dry non-woven fibrous mat, the improvement comprising applying a foam or froth onto the wet web after said wet web has been partially dewatered following the binder application, the foam or froth containing a high percentage of air and having a blow ratio of at least about 12, the foam forming less than 5 milliliters of liquid in the bottom of an Imhoff cone after 16 hours, from the time of filling the cone to a one liter mark, and a viscosity of at least about 200 centipoise, and applying said foam at a rate to produce a dry mat having a coating on one face, the mat having a permeability of at least about 150 CFM/sq. ft.