Patent ID: 7547375

Claim:
A method for making a fibrous nonwoven mat facer suitable as a backer mat, connector sheet, in a compressible ceiling panel of the type described in U.S. Published Patent Application No. 200200020142, filed Apr. 23, 2001, comprising; a) dispersing glass fibers having an average fiber diameter of 13+/−1.5 microns and a length of about 0.75+/−0.15 inch in an aqueous dispersion, b) draining said dispersion through a moving forming screen to form a wet fibrous web, c) applying an aqueous resin binder to the wet web and removing excess binder to produce a binder content in the web, after drying, in the range of about 15+/−3 wt. percent, the aqueous binder comprising a mixture of water and a resin formed from a homopolymer or a copolymer of polyacrylic acid and a polyol, the average molecular weight of the homopolymer or a copolymer of polyacrylic acid being less than about 5000 and the aqueous binder having a pH of less than about 2.5 controlling steps b and c to produce a wet mat, that when dry, has a basis wt. of 2.5+/−0.2 pounds per 100 sq. feet and a thickness in the range of 47+/−5 mils; and d) drying the wet web and at least partially curing the resin in the binder to form an essentially formaldehyde free resin bound fibrous non woven mat containing glass fibers in amounts of about 65 to about 90 wt. percent that; passes the flammability test of NFPA, Method #701, has a Taber stiffness of greater than about 50, and has an air permeability in the range of about 500 to about 800 CFM/sq. ft.