Patent ID: 7147734

Claim:
A method for forming a fire combustion modified batt comprising: forming a first blend consisting of oxidized polyacrylonitrile fibers, polyester carrier fibers and polyester binder fibers in which said polyester carrier fibers and said oxidized polyacrylonitrile fibers have a combined volume of between 60 percent and 90 percent of said blend, said polyester binder fibers having a low melting temperature relative to said polyester carrier fibers and said polyester carrier fibers having a high melting temperature relative to said polyester binder fibers; forming said first blend of fibers into a first web of indeterminate length; forming a second blend consisting of polyester carrier fibers and polyester binder fibers, said polyester binder fibers having a low melting temperature relative to said polyester carrier fibers and said polyester carrier fibers having a high melting temperature relative to said polyester binder fibers; forming said second blend of fibers into a second web of indeterminate length; disposing a surface of said first web with a surface of said second web to form a batt; compressing said batt; heating said batt at a temperature at or above the melting temperature of said polyester binder fibers and below the melting temperature of said polyester carrier fibers; and cooling said batt while compressed to (a) fuse said polyester binder fibers of said first web of said batt to (i) each other, (ii) said polyester carrier fibers of said first web of said batt and (iii) said oxidized polyacrylonitrile fibers of said first web of said batt; (b) fuse said polyester binder fibers of said second web of said batt to (i) each other and (ii) said polyester carrier fibers of said second web; and (c) fuse the surfaces of said first and said second webs together.