Glass fiber bundles for mat applications and methods of making the same

Abstract

Dried bundles of chopped glass fibers that may be used in mat forming applications is provided. The chopped glass fiber bundles are formed of individual glass fibers positioned in a substantial parallel orientation. The dried chopped glass fiber bundles may be prepared by applying a size composition to attenuated glass fibers, splitting the fibers to obtain a desired bundle tex, chopping the wet glass bundles to a discrete length, and drying the wet glass bundles in a dielectric oven, a Cratec® oven, or a rotating tray oven. Alternatively, the dried chopped glass bundles may be prepared by sizing attenuated glass fibers, passing the sized fibers through a heat transfer chamber where air heated by a bushing is drawn into the heat transfer chamber to dry the glass fiber bundles, splitting the dried, sized glass fiber bundles to obtain a desired bundle tex, and chopping the dried bundles of glass fibers.

1 . A chopped glass fiber bundle for use in mat forming applications comprising: 
 a plurality of substantially parallel glass fibers positioned in a bundled orientation, said glass fibers being at least partially coated with a size composition that maintains said plurality of glass fibers in said bundled orientation during the formation and subsequent processing of glass fibers in said bundled orientation;    wherein said sizing composition includes: 
 one or more film forming agents selected from the group consisting of a polyurethane film former, an unsaturated polyester film former and an epoxy resin film former;  
 at least one silane coupling agent; and  
 at least one lubricant.  
   
     
     
         2 . The chopped glass fiber bundle of  claim 1 , wherein said plurality of glass fibers have a bundle tex of about 20 to about 200 g/km.  
     
     
         3 . The chopped glass fiber bundle of  claim 1 , wherein said glass fibers are wet use chopped strand glass fibers.  
     
     
         4 . The chopped glass fiber bundle of  claim 1 , wherein said film forming agent is a polyurethane film forming agent and said size composition further comprises a polyurethane-acrylic alloy.  
     
     
         5 . The chopped glass fiber bundle of  claim 1 , wherein said film forming agent is an epoxy resin film former and said size composition further comprises an epoxy curative.  
     
     
         6 . The chopped glass fiber bundle of  claim 1 , wherein said film forming agent is an unsaturated polyester film forming agent and said size composition further comprises a benzoyl peroxide curing catalyst.  
     
     
         7 . The chopped glass fiber bundle of  claim 1 , wherein said one or more film forming agent is present in said size composition in an amount of from about 80 to about 95% by weight total solids, said at least one silane coupling agent is present in said size composition in an amount of from about 3 to about 15% by weight total solids, and said at least one lubricant is present in said size composition in an amount of from about 0.1 to about 2% by weight total solids.  
     
     
         8 . The chopped glass fiber bundle of  claim 1 , wherein said at least one silane coupling agent is selected from the group consisting of an aminosilane coupling agent and a methacryloxy silane coupling agent.  
     
     
         9 . The chopped glass fiber bundle of  claim 1 , wherein said size composition filamentizes said glass fibers in said bundled orientation during future processing to form an aesthetically pleasing final product.  
     
     
         10 . A method of forming chopped glass fiber bundles comprising the steps of: 
 applying a size composition to a plurality of attenuated glass fibers, said size composition including: 
 one or more film forming agents selected from the group consisting of a polyurethane film former, an unsaturated polyester film former and an epoxy resin film former;  
 at least one silane coupling agent; and  
 at least one lubricant;  
   splitting said plurality of glass fibers into glass fiber strands having a predetermined number of glass fibers therein;    chopping said glass fiber strands to form wet chopped glass fiber bundles, said wet chopped glass fiber bundles having a discrete length; and    drying said wet chopped glass fiber bundles in a drying oven selected from the group consisting of a dielectric oven, a fluidized bed oven and a rotating tray thermal oven to form chopped glass fiber bundles.    
     
     
         11 . The method of forming chopped glass fiber bundles according to  claim 10 , wherein said predetermined number of glass fibers in said glass fiber strands is a number sufficient to provide a bundle tex of about 20 to about 200 g/km.  
     
     
         12 . The method of forming chopped glass fiber bundles according to  claim 10 , further comprising the step of: 
 depositing said wet chopped glass fibers onto a conveyor prior to said drying step.    
     
     
         13 . The method of forming chopped glass fiber bundles according to  claim 10 , wherein greater than or equal to about 99% of the water external to said wet chopped glass fiber bundles is removed in said drying oven.  
     
     
         14 . The method of forming chopped glass fiber bundles according to  claim 13 , wherein said oven is said dielectric oven; and 
 wherein said drying step comprises: 
 passing said wet chopped glass fiber bundles through successive oppositely charged electrodes positioned in said dielectric oven to cause water within said wet chopped fiber bundles to evaporate without agitating said wet chopped fiber bundles.  
   
     
     
         15 . The method of forming chopped glass fiber bundles according to  claim 13 , wherein said wet chopped fiber bundles are dried in a fluidized bed and the sizing composition on said glass fibers is solidified using a hot air flow having a controlled temperature.  
     
     
         16 . A method of forming chopped glass fiber bundles comprising the steps of: 
 applying a size composition to a plurality of glass fibers attenuated by a bushing, said size composition including: 
 one or more film forming agents selected from the group consisting of a polyurethane film former, an unsaturated polyester film former and an epoxy resin film former;  
 at least one silane coupling agent; and  
 at least one lubricant;  
   passing said plurality of sized glass fibers through a heat transfer chamber where air heated by said bushing is drawn into said heat transfer chamber to substantially dry said plurality of sized glass fibers and form dried glass fibers;    splitting said dried glass fibers into glass fiber strands having a predetermined number of said dried glass fibers therein; and    chopping said glass fiber strands to form chopped glass fiber bundles, said chopped glass fiber bundles having a discrete length.    
     
     
         17 . The method of forming chopped glass fiber bundles according to  claim 16 , further comprising the step of: 
 gathering said glass fiber strands into a single tow prior to chopping said glass fiber strands.    
     
     
         18 . The method of forming chopped glass fiber bundles according to  claim 16 , wherein said predetermined number of glass fibers in said glass fiber strands is a number sufficient to provide a bundle tex of about 20 to about 200 g/km.  
     
     
         19 . The method of forming chopped glass fiber bundles according to  claim 16 , further comprising the step of: 
 heating said chopped glass fiber bundles in a drying oven selected from the group consisting of a dielectric oven, a fluidized bed oven and a rotating tray thermal oven to further dry said chopped glass fiber bundles.    
     
     
         20 . The method of forming chopped glass fiber bundles according to  claim 16 , wherein said splitting step occurs prior to said dried glass fibers exiting said heat transfer chamber.