Wet formed mat having improved hot wet tensile strengths

Abstract

Wet-laid chopped strand glass mats for use in roofing applications that have improved hot wet tensile strengths are provided. The chopped strand mats are formed by the application or inclusion of at least one coupling agent to the chopped strand mat during a wet-laid mat forming process. The coupling agent may be added to the chopped strand mat as part of a two-part binder composition that includes a binder and at least one coupling agent. Alternatively, the coupling agent may be added directly to the chopped strand mat independent of the binder. As a further alternative, the coupling agent(s) may be added to the white water in the wet-laid mat forming process and incorporated into the formed glass mat via the glass fibers. The binder may be a modified urea-formaldehyde binder, a non-modified urea-formaldehyde binder, and/or a formaldehyde-free binder. The coupling agent(s) may be silane coupling agents and/or reactive siloxanes.

1 . A method of forming a chopped strand glass mat for use in roofing applications comprising the steps of: 
 applying at least one coupling agent to a member selected from the group consisting of a fibrous web and glass fibers during a wet-laid mat forming process, said wet-laid mat forming process including: 
 dispersing chopped glass fibers in an aqueous medium to form a glass fiber slurry;  
 depositing said glass fiber slurry onto a conveying apparatus to form a fibrous web;  
 adding a binder to said fibrous web; and  
 curing said binder to form a chopped strand glass mat.  
   
     
     
         2 . The method of  claim 1 , wherein said applying step comprises adding said at least one coupling agent to said aqueous medium, said at least one coupling agent being deposited on said chopped glass fibers in said aqueous medium.  
     
     
         3 . The method of  claim 1 , wherein said applying step comprises adding said at least one coupling agent to said binder to form a binder composition including said binder and said at least one coupling agent prior to adding said binder to said fibrous web.  
     
     
         4 . The method of  claim 1 , wherein said applying step comprises depositing said at least one coupling agent on said fibrous web prior to said curing step.  
     
     
         5 . The method of  claim 4 , wherein said applying step comprises depositing said at least one coupling agent on said fibrous web prior to adding said binder to said fibrous web.  
     
     
         6 . The method of  claim 4 , wherein said applying step comprises depositing said at least one coupling agent on said fibrous web after adding said binder to said fibrous web.  
     
     
         7 . The method of  claim 1 , wherein said at least one coupling agent is selected from the group consisting of silane coupling agents, functionalized organic substrates, silicon-containing coupling agents functionalized with a polymer, reactive siloxanes and combinations thereof; and 
 wherein said binder composition is selected from the group consisting of a modified formaldehyde binder, a non-modified formaldehyde binder, a modified urea-formaldehyde binder, a non-modified urea-formaldehyde binder, a formaldehyde-free binder and combinations thereof.    
     
     
         8 . The method of  claim 7 , wherein said functionalized organic substrates are selected from the group consisting of alcohols, amines, esters, ethers, hydrocarbons, siloxanes, silazanes, silanes, silanols, lactams, lactones, anhydrides, carbenes, nitrenes, orthoesters, imides, enamines, imines, amides, imides and olefins.  
     
     
         9 . The method of  claim 1 , wherein said chopped strand mat has a dry tensile strength, a hot wet tensile strength and a resultant hot wet tensile retention percentage of said dry tensile strength, and 
 wherein said hot wet tensile retention percentage of said chopped strand mat having said coupling agent is at least five percent greater than an otherwise identical chopped strand mat without said coupling agent.    
     
     
         10 . The method of  claim 9 , wherein said hot wet tensile retention percentage of said chopped strand mat having said coupling agent is greater than fifty percent (50%) and an otherwise identical chopped strand mat without said coupling agent has a hot wet tensile retention percentage of less than fifty percent (50%).  
     
     
         11 . The method of  claim 10 , wherein said step of applying said at least one coupling agent comprises adding said coupling agent to said binder to form a binder composition, said coupling agent being added in an amount of 0.1- 1.0% by weight based on the active solids in said binder composition.  
     
     
         12 . The method of  claim 10 , wherein said step of applying said at least one coupling agent comprises adding said coupling agent to said fibrous web in an amount up to 1% by weight of said fibrous web.  
     
     
         13 . A two-part binder composition for use in a wet-laid mat forming process for forming a glass mat useful as a reinforcement in roofing applications comprising: 
 a binder pre-mix including a binder selected from the group consisting of a modified formaldehyde binder, a non-modified formaldehyde binder, a modified urea-formaldehyde binder, a non-modified urea-formaldehyde binder, a formaldehyde-free binder and combinations thereof; and    at least one coupling agent.    
     
     
         14 . The two-part binder composition according to  claim 13 , wherein said at least one coupling agent is selected from the group consisting of silane coupling agents, functionalized organic substrates, silicon-containing coupling agents finctionalized with a polymer, reactive siloxanes and combinations thereof.  
     
     
         15 . The two-part binder composition according to  claim 14 , wherein said at least one coupling agent is a silane coupling agent selected from the group consisting of aminosilanes, silane esters, vinyl silanes, methacryloxy silanes, epoxy silanes, sulfur silanes, ureido silanes and isocyanato silanes.  
     
     
         16 . The two-part binder composition according to  claim 14 , further comprising at least one organic acid selected from the group consisting of acetic acid, formic acid, succinic acid and citric acid.  
     
     
         17 . The two-part binder composition according to  claim 14 , wherein said binder is a urea-formaldehyde binder modified with a styrene butadiene rubber latex modifier and said at least one coupling agent is at least one aminosilane coupling agent.  
     
     
         18 . The two-part binder composition according to  claim 13 , wherein said modified urea-formaldehyde binder and modified formaldehyde binder are modified with a member selected from the group consisting of latex, styrene butadiene latex, a styrene/maleic anhydride copolymer, polyvinyl acetate, a vinyl acrylic copolymer, melamine, melamine derivatives and combinations thereof, and 
 wherein said formaldehyde-free binder is selected from a member selected from the group consisting of an acrylic binder, a styrene acrylonitrile binder, a styrene butadiene rubber binder, polyvinyl acetate binders, vinyl acrylic binders, polyurethane binders and combinations thereof.    
     
     
         19 . A method of forming a non-woven chopped strand mat for use in roofing applications comprising the steps of: 
 depositing a glass fiber slurry on a conveying apparatus to form a fibrous web of intermeshed glass fibers;    applying a binder to said fibrous web;    applying at least one coupling agent to said fibrous web; and    curing said binder.    
     
     
         20 . The method of forming a non-woven chopped strand glass mat according to  claim 19 , wherein said binder and said at least one coupling agent are applied to said fibrous web simultaneously as a two-part binder composition.  
     
     
         21 . The method of forming a non-woven chopped strand glass mat according to  claim 19 , wherein said step of applying said binder to said fibrous web and said step of applying said at least one coupling agent occur sequentially.  
     
     
         22 . The method of forming a non-woven chopped strand glass mat according to  claim 21 , wherein said step of applying said binder to said fibrous web occurs prior to said step of applying said at least one coupling agent to said fibrous web.  
     
     
         23 . The method of forming a non-woven chopped strand glass mat according to  claim 21 , wherein said step of applying said binder to said fibrous web occurs after said step of applying said at least one coupling agent to said fibrous web.  
     
     
         24 . The method of forming a non-woven chopped strand glass mat according to  claim 19 , further comprising the step of: 
 dispersing glass fibers in an aqueous medium to form said glass fiber slurry prior to said depositing step.    
     
     
         25 . The method of forming a non-woven chopped strand glass mat according to  claim 19 , wherein said binder is selected from the group consisting of a modified formaldehyde binder, a non-modified formaldehyde binder, a modified urea-formaldehyde binder, a non-modified urea-formaldehyde binder, a formaldehyde-free binder and combinations thereof; and 
 wherein said at least one coupling agent is selected from the group consisting of silane coupling agents, functionalized organic substrates, silicon-containing coupling agents functionalized with a polymer, reactive siloxanes, and combinations thereof.    
     
     
         26 . A glass mat for use as a reinforcement comprising: 
 a plurality of glass fibers combined in the form of a sheet; and    a binder and at least one coupling agent for bonding together said glass fibers.    
     
     
         27 . The non-woven chopped strand glass mat of  claim 26 , wherein said at least one coupling agent is selected from the group consisting of silane coupling agents, functionalized organic substrates, silicon-containing coupling agents functionalized with a polymer, reactive siloxanes and combinations thereof.  
     
     
         28 . The non-woven chopped strand glass mat of  claim 27 , wherein said at least one coupling agent is a silane coupling agent selected from the group consisting of aminosilanes, silane esters, vinyl silanes, methacryloxy silanes, epoxy silanes, sulfur silanes, ureido silanes and isocyanato silanes.  
     
     
         29 . The non-woven chopped strand glass mat of  claim 26 , wherein said binder is selected from the group consisting of a modified formaldehyde binder, a non-modified formaldehyde binder, a modified urea-formaldehyde binder, a non-modified urea-formaldehyde binder, a formaldehyde-free binder and combinations thereof.  
     
     
         30 . The non-woven chopped strand glass mat of  claim 26 , further comprising reinforcing fibers selected from the group consisting of mineral fibers, carbon fibers, ceramic fibers, natural fibers and synthetic fibers.  
     
     
         31 . The non-woven chopped strand glass mat of  claim 26 , wherein said chopped strand mat has a dry tensile strength, a hot wet tensile strength and a resultant hot wet tensile retention percentage of dry tensile strength, and 
 wherein said hot wet tensile retention percentage of said chopped strand mat having said coupling agent is at least five percent greater than an otherwise identical chopped strand mat without said coupling agent.    
     
     
         32 . The non-woven chopped strand glass mat of  claim 31 , wherein said hot wet tensile retention percentage of said chopped strand mat having said coupling agent is greater than fifty percent (50%) and an otherwise identical chopped strand mat without said coupling agent has a hot wet tensile retention percentage of less than fifty percent (50%).  
     
     
         33 . The non-woven chopped strand glass mat of  claim 32 , wherein said coupling agent is present in said binder composition in an amount of 0.1- 1.0% by weight based on the active solids in the binder composition.  
     
     
         34 . A method of forming a non-woven chopped strand mat for use in roofing applications comprising the steps of: 
 incorporating chopped glass fibers into an aqueous medium including at least one coupling agent;    agitating said aqueous medium to disperse said chopped glass fibers within said aqueous medium to form a fibrous slurry and to deposit said at least one coupling agent on said chopped glass fibers;    depositing said fibrous slurry onto a conveying apparatus to form a web of intermeshed said chopped glass fibers;    applying a binder to said web; and    curing said binder to form a chopped strand glass mat.    
     
     
         35 . The method of  claim 34 , wherein said at least one coupling agent is selected from the group consisting of silane coupling agents, functionalized organic substrates, silicon-containing coupling agents functionalized with a polymer and reactive siloxanes.  
     
     
         36 . The method of  claim 35 , wherein said coupling agent is a silane coupling agent selected from the group consisting of aminosilanes, silane esters, vinyl silanes, methacryloxy silanes, epoxy silanes, sulfur silanes, ureido silanes and isocyanato silanes.  
     
     
         37 . The method of  claim 36 , wherein said binder is selected from the group consisting of a modified formaldehyde binder, a non-modified formaldehyde binder, modified urea-formaldehyde binder, a non-modified urea-formaldehyde binder, a formaldehyde-free binder and combinations thereof.  
     
     
         38 . The method of  claim 34 , further comprising the step of adding reinforcing fibers selected from the group consisting of mineral fibers, carbon fibers, ceramic fibers, natural fibers and synthetic fibers to said aqueous medium prior to said agitating step.