Method of making tough, flexible mats

摘要

A method of making a nonwoven fibrous mat that retains good strength and recovery after scoring and folding, properties making the mat useful in making collapsible ceiling tile. The mat comprises a majority of glass fibers and a minority of polymer fibers, the fibers being bound together with up to 35 wt. percent of a polyacrylic acid and polyol polymer binder based on the dry weight of the mat. The mat can be cured to “B stage”, thermoformed into the desired shape and then heated further to complete the cure of the binder.

主权项

1. 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. 20020002142, filed Apr. 23, 2001, comprising;
a) dispersing fibers comprising two different types of fibers in a fluid dispersion, the fibers comprising 65-95 wt. percent glass fibers having an average diameter in the range of about 13 to about 17.5 microns and a length in the range of about 0.7 to about 1.1 inches, and about 5 to about 35 wt. percent man-made polymer fibers selected from a group consisting of polyester, polypropylene, nylon, PBT, polyacrynitrile and polybenzimidizole, b) subjecting the dispersion to a moving forming screen to form a fibrous web, c) applying an aqueous resin binder to the web, the binder comprised of polyacrylic acid homopolymer and a polyol having an average molecular weight of 3000 or less, the amount of binder applied amounting to a range of about 10 to about 35 wt. percent of the dried mat, and d) drying the wet web and at least partially curing the resin in the binder to form a resin bound fibrous nonwoven mat, wherein;
i) the fibrous nonwoven mat having a basis weight of about 2.3 to about 2.6 pounds per 100 square feet, a thickness of about 42+/−3 mils, a wet tensile strength of at least 35 percent of the dry tensile strength, a Tabor stiffness of at least about 40, an air permeability in the range of about 500 to about 800 CFM/sq. ft and passing the flammability test of NFPA, Method #701.