Fiber mat, method of making the fiber mat, and bituminous roofing product

Abstract

A fiber mat includes an assembly of fibers including a minority portion including a set of polymer fibers and a majority portion including a set of fibers different than the minority portion, wherein the minority portion is a plane parallel to a plane of the majority portion of the assembly of fibers; and a binder including an organic resin, wherein an air permeability of said fiber mat is not substantially different from an equivalent weight fiber mat containing a homogenous mat structure and wherein the fiber mat provides at least a 5% increase in tear when placed in a bituminous roofing product compared to an equivalent bituminous roofing product made with the equivalent weight fiber mat containing the homogenous mat structure.

What is claimed is: 
     
         1 . A method of making a fiber mat comprises:
 providing an assembly of fibers comprising a minority portion comprising a set of polymer fibers and a majority portion comprising a set of fibers different than the minority portion, wherein the minority portion is a plane parallel to a plane of the majority portion of the assembly of fibers;   applying a binder to the assembly of fibers, wherein the binder comprises an organic resin; and   curing the binder, wherein an air permeability of said fiber mat is not substantially different from an equivalent weight fiber mat containing a homogenous mat structure and wherein the fiber mat provides at least a 5% increase in tear when placed in a bituminous roofing product compared to an equivalent bituminous roofing product made with the equivalent weight fiber mat containing the homogenous mat structure.   
     
     
         2 . The method of  claim 1 , wherein providing the assembly of fibers comprises providing the set of fibers of the majority portion and subsequently providing the set of polymer fibers of the minority portion. 
     
     
         3 . The method of  claim 1 , wherein the fiber mat has an air permeability of at least 750 CFM/ft 2 . 
     
     
         4 . The method of  claim 1 , wherein the polymer fibers have a melting temperature (T m ) greater than about 200° C. 
     
     
         5 . The method of  claim 4 , wherein the polymer fibers comprise polyester, polyethylene terephthalate, polyvinyl alcohol (PVA), polyvinyl chloride (PVC), polyether ether ketone (PEEK), polyether ketone (PEK), polyacrylonitrile, polystyrene, nylon, polymethyl methacrylate (PMMA), polybenzimidazole (PBI), polyimide, polyether imide (PEI), polyamide-imide (PAI), polyether sulfone (PES), polyphenyl sulfone (PPSU), polyphenylsulfide (PPS), liquid crystal polymer (LCP), ethylene tetrafluoroethylene (ETFE), polytetrafluoroethylene (PTFE), perfluoroalkoxy alkane (PFA), a blend, or combination thereof. 
     
     
         6 . The method of  claim 5 , wherein the polymer fibers comprise polyethylene terephthalate. 
     
     
         7 . The method of  claim 1 , wherein the polymer fibers are present at an amount of about 0.5 weight % to about 10 weight % of the total weight of the assembly of fibers. 
     
     
         8 . The method of  claim 1 , wherein the minority portion is directly in contact with the majority portion at an interface, wherein the interface has a substantially distinct segregation between the minority portion and the majority portion. 
     
     
         9 . The method of  claim 1 , wherein a center plane of the minority portion is closer in distance to one surface of the fiber mat. 
     
     
         10 . The method of  claim 1 , wherein a center plane of the minority portion is approximately coincident to a center plane of the fiber mat. 
     
     
         11 . The method of  claim 1 , wherein the minority portion comprises a substantially random orientation of chopped fibers. 
     
     
         12 . The method of  claim 1 , wherein the majority portion comprises a substantially random orientation of chopped fibers. 
     
     
         13 . The method of  claim 1 , wherein the set of fibers of the majority portion comprises a glass fiber, a polymer fiber, a basalt fiber, a mineral fiber, or combination thereof. 
     
     
         14 . The method of  claim 1 , wherein the binder is substantially uniformly distributed throughout the fiber mat. 
     
     
         15 . The method of  claim 1 , wherein the fiber mat has a tensile strength at least 80% of a value of tensile strength of a fiber mat of equivalent weight containing a homogenous mat structure. 
     
     
         16 . The method of  claim 1 , wherein the fiber mat has a tensile strength at least 80% of a value of tensile strength of a higher caliper fiber mat having a homogenous mat structure. 
     
     
         17 . The method of  claim 1 , wherein a bituminous roofing product comprising the fiber mat has a tear strength at least 80% of a value of tear strength of an equivalent bituminous roofing product comprising a higher caliper fiber mat having a homogenous mat structure. 
     
     
         18 . The method of  claim 1 , wherein the organic resin comprises a urea-formaldehyde composition, a latex composition, a styrene-butadiene rubber (SBR) composition, a vinyl acetate ethylene composition, a blend or combination thereof. 
     
     
         19 . The method of  claim 1 , further comprising coating the fiber mat with at least one layer of asphalt. 
     
     
         20 . The method of  claim 19 , wherein the asphalt substantially impregnates a plurality of interstices between the assembly of fibers.