Methods of forming low static non-woven chopped strand mats

Abstract

A method of forming a chopped strand mat formed of bonding materials and wet use chopped strand glass fibers (WUCS) which demonstrate a reduced occurrence of static electricity is provided. In one exemplary embodiment, the occurrence of static electricity on the glass fibers is reduced or eliminated by increasing the total solids content on the glass fibers, such as by applying an increased or excess amount of size composition to the glass fibers. Alternatively, an anti-static agent may be added directly to the sizing composition and applied to the glass filaments by any suitable application device. The antistatic agent may be applied to the wet chopped strand glass prior to chopping the strands or as the wet chopped strands are packaged. The static free wet use chopped strand glass fibers may be used in dry-laid processes to form chopped strand mats having a reduced tendency to accumulate static electricity.

1 .- 19 . (canceled) 
     
     
         20 . A method of forming a low-static non-woven chopped strand mat comprising:
 forming wet use chopped strand glass fibers having a size composition applied to at least a portion of a surface thereof;   applying an antistatic agent to a surface of said sized wet use chopped strand glass fibers, said antistatic agent being positioned on said size composition;   removing water from said wet use chopped strand glass fibers to form dried chopped strand fibers;   blending said dried chopped fibers and a thermoplastic bonding material to form a mixture of said dried chopped fibers and said thermoplastic bonding material;   forming said mixture of said dried chopped fibers and said thermoplastic bonding material into a sheet; and   bonding at least a portion of said dried chopped fibers and said thermoplastic bonding material to form a chopped strand mat.   
     
     
         21 . The method of  claim 20 , wherein said antistatic agent is applied to said sized wet use chopped strand glass fibers in an amount from about 0.05 to about 0.20% by weight solids, said antistatic agent being substantially uniformly distributed on said sized wet use chopped strand glass fibers. 
     
     
         22 . The method of  claim 20 , wherein said antistatic agent is selected from quaternary ammonium compounds, tetraethylammonium chloride, lithium chloride, fatty acid esters and ethoxylated amines 
     
     
         23 . The method of  claim 20 , wherein said bonding step comprises:
 heating said sheet to a temperature above the melting point of said thermoplastic bonding material and below the melting point of said dried chopped fibers to at least partially melt said thermoplastic bonding material and bond at least a portion of said dried chopped fibers and said thermoplastic bonding material.   
     
     
         24 . The method of  claim 23 , further comprising the step of:
 subjecting said sheet to a needling process to mechanically bond said dried chopped fibers and said thermoplastic bonding material prior to said bonding step.   
     
     
         25 . The method of  claim 20 , wherein said bonding step comprises:
 subjecting said sheet to a needling process to mechanically bond said dried chopped fibers and said thermoplastic bonding material,   wherein said thermoplastic bonding material is at least one material selected from thermoplastic fibers, thermosetting fibers and bicomponent fibers.   
     
     
         26 . A method of forming a low-static non-woven chopped strand mat comprising:
 supplying wet use chopped strand glass fibers having a size composition substantially evenly applied to at least a portion of a surface thereof;   removing water from said wet use chopped strand glass fibers to form dried chopped strand fibers;   blending said dried chopped fibers and a thermoplastic bonding material to form a mixture of said dried chopped fibers and said thermoplastic bonding material;   forming said mixture of said dried chopped fibers and said thermoplastic bonding material into a sheet; and   bonding at least a portion of said dried chopped fibers and said thermoplastic bonding material to form a chopped strand mat.   
     
     
         27 . The method of  claim 26 , wherein said supplying step comprises:
 adding an antistatic agent to a size composition including a film forming agent, a lubricant, and a coupling agent to form a modified size composition; and   applying said modified size composition containing said antistatic agent to a surface of said wet use chopped strand glass fibers.   
     
     
         28 . The method of  claim 26 , wherein said antistatic agent is present in said modified size composition in an amount from about 0.05 to about 0.2% by weight solids. 
     
     
         29 . The method of  claim 28 , wherein said bonding step comprises:
 heating said sheet to a temperature above the melting point of said thermoplastic bonding material and below the melting point of said dried chopped fibers to at least partially melt said thermoplastic bonding material and bond at least a portion of said dried chopped fibers and said thermoplastic bonding material.   
     
     
         30 . The method of  claim 28 , wherein said bonding step comprises:
 subjecting said sheet to a needling process to mechanically bond said dried chopped fibers and said thermoplastic bonding material,   wherein said thermoplastic bonding material is at least one material selected from thermoplastic fibers, thermosetting fibers and bicomponent fibers.   
     
     
         31 . The method of  claim 26 , wherein said size composition comprises a film forming agent, a lubricant, and a coupling agent, and
 wherein said size composition is applied to said wet use chopped strand glass fibers with an increased total solids content as compared to a total solids content of a size composition containing a film forming agent, a lubricant, and a coupling agent conventionally applied to said wet use chopped strand glass fibers.   
     
     
         32 . The method of  claim 31 , wherein a solids content of each component of said size composition is increased and a ratio of the individual components of said size composition is maintained. 
     
     
         33 . The method of  claim 31 , wherein said size composition is applied to said wet use chopped strand glass fibers in an increased amount, said increased amount being from about 0.4 to about 2.0% by weight solids. 
     
     
         34 . A method of forming a low-static non-woven chopped strand mat comprising:
 supplying wet use chopped strand glass fibers having a modified size composition including a film forming agent, a lubricant, and a coupling agent substantially evenly applied to at least a portion of a surface thereof, said modified size composition having an increased content of hydrophilic components compared to conventional size compositions containing a film forming agent, a lubricant, and a coupling agent;   removing water from said wet use chopped strand glass fibers to form dried chopped strand fibers;   blending said dried chopped fibers and a thermoplastic bonding material to form a mixture of said dried chopped fibers and said thermoplastic bonding material;   forming said mixture of said dried chopped fibers and said thermoplastic bonding material into a sheet; and   bonding at least a portion of said dried chopped fibers and said thermoplastic bonding material to form a chopped strand mat.   
     
     
         35 . The method of  claim 34 , wherein said amount of hydrophilic components present on said wet use chopped strand glass fibers is at least  0 . 05 % by weight solids. 
     
     
         36 . The method of  claim 35 , wherein said amount of hydrophilic components present on said wet use chopped strand glass fibers is from about 0.4 to about 2.0% by weight solids. 
     
     
         37 . The method of  claim 35 , further comprising:
 increasing an amount of said film forming agent and said lubricant present in said size composition to obtain said increased content of hydrophilic components.   
     
     
         38 . The method of  claim 34 , wherein said bonding step comprises:
 heating said sheet to a temperature above the melting point of said thermoplastic bonding material and below the melting point of said dried chopped fibers to at least partially melt said thermoplastic bonding material and bond at least a portion of said dried chopped fibers and said thermoplastic bonding material.   
     
     
         39 . The method of  claim 34 , wherein said bonding step comprises:
 subjecting said sheet to a needling process to mechanically bond said dried chopped fibers and said thermoplastic bonding material,   wherein said thermoplastic bonding material is at least one material selected from thermoplastic fibers, thermosetting fibers and bicomponent fibers.   
     
     
         40 . The method of  claim 34 , wherein said antistatic agent is selected from quaternary ammonium compounds, tetraethylammonium chloride, lithium chloride, fatty acid esters and ethoxylated amines