Infusible unidirectional fabric

Abstract

An infusible, unidirectional fabric containing a plurality of unidirectional fibers spaced uniformly in the unidirectional fabric, a plurality of bridges, and a plurality of void spaces between the unidirectional fibers. Each bridge is connected to at least 2 unidirectional fibers and at least 70% by number of fibers have at least one bridge connected thereto forming a bridged network of unidirectional fibers. The void spaces are interconnected and the fabric has a volume fraction of voids of between about 8 and 70%, a volume fraction of fibers of between about 35 and 85%, and at least 50% by number of the bridges have a bridge width minimum less than about 2 millimeters.

What is claimed is: 
     
         1 . An infusible, unidirectional fabric having an upper inner surface and a lower inner surface comprising:
 a plurality of unidirectional fibers having a diameter and a length, wherein the unidirectional fibers are spaced uniformly in the unidirectional fabric;   a plurality of bridges, each bridge being connected to at least 2 unidirectional fibers and wherein at least 70% by number of fibers comprise at least one bridge connected thereto forming a bridged network of unidirectional fibers, wherein the bridges comprise a bridging polymer, wherein between the unidirectional fibers the bridges each have a width and a bridge width minimum, and wherein at least 50% by number of the bridges have a bridge width minimum less than about 2 millimeters; and,   a plurality of void spaces between the unidirectional fibers, wherein the void spaces are interconnected, wherein the fabric has a volume fraction of voids of between about 8 and 70%, and wherein the fabric has a volume fraction of fibers of between about 35 and 85%.   
     
     
         2 . The infusible unidirectional fabric of  claim 1 , wherein the bridged network of unidirectional fibers have a tensile strength of at least 200 Pa in the direction perpendicular to the unidirectional fibers. 
     
     
         3 . The infusible, unidirectional fabric of  claim 1 , wherein the bridging polymer forms between about 0.1 and 30% of the effective cross-sectional area of the infusible, unidirectional fabric. 
     
     
         4 . The infusible, unidirectional fabric of  claim 1 , wherein the unidirectional fibers comprise a material selected from the group consisting of glass, carbon, aramid, polyethylene, polyester, polyamide, and mixtures thereof. 
     
     
         5 . The infusible, unidirectional fabric of  claim 1 , wherein the infusible, unidirectional fabric does not comprises any stitching fibers or yarns. 
     
     
         6 . An infused, unidirectional composite comprising:
 at least one unidirectional fabric having an upper inner surface and a lower inner surface, the unidirectional fabric comprising a plurality of unidirectional fibers having a diameter and a length, wherein the unidirectional fibers are spaced uniformly in the unidirectional fabric;   a plurality of bridges, each bridge being connected to at least 2 unidirectional fibers and wherein at least 70% by number of fibers comprise at least one bridge connected thereto forming a bridged network of unidirectional fibers, wherein the bridges comprise a bridging polymer, wherein between the unidirectional fibers the bridges each have a width and a bridge width minimum, and wherein at least 50% by number of the bridges have a bridge width minimum less than about 2 millimeters; and,   a cured resin between the unidirectional fibers, wherein the cured resin is continuous through the composite, wherein the composite has a volume fraction of cured resin of between about 8 and 70%, and wherein the composite has a volume fraction of fibers of between about 35 and 85%.   
     
     
         7 . The infused, unidirectional composite of  claim 6 , wherein the bridging polymer forms between wherein the bridging polymer forms between about 0.1 and 30% of the effective cross-sectional area of the infused, unidirectional composite. 
     
     
         8 . The infused, unidirectional composite of  claim 6 , wherein the composite comprises at least two or more adjacent unidirectional fabrics. 
     
     
         9 . A structure comprising the infused, unidirectional composite of  claim 6 . 
     
     
         10 . The structure of  claim 9 , wherein the structure is selected from the group consisting of wind turbine blades, bridges, boat hulls, boat decks, rail cars, pipes, tanks, reinforced truck floors, pilings, fenders, docks, reinforced wood beams, retrofitted concrete structures, aircraft structures, reinforced extrusions and injection moldings. 
     
     
         11 . A wind turbine blade comprising an infused, unidirectional composite in a section of the wind turbine blade selected from the group consisting of spar section, a root section, leading edge, trailing edge, wherein the infused, unidirectional composite comprises:
 a plurality of unidirectional fibers having a diameter and a length, wherein the unidirectional fibers are spaced uniformly in the unidirectional fabric;   a plurality of bridges, each bridge being connected to at least 2 unidirectional fibers and wherein at least 70% by number of fibers comprise at least one bridge connected thereto forming a bridged network of unidirectional fibers, wherein the bridges comprise a bridging polymer, wherein between the unidirectional fibers the bridges each have a width and a bridge width minimum, and wherein at least 50% by number of the bridges have a bridge width minimum less than about 2 millimeters; and,   a cured resin between the unidirectional fibers, wherein the cured resin is continuous through the composite, wherein the composite has a volume fraction of cured resin of between about 8 and 70%, and wherein the composite has a volume fraction of fibers of between about 35 and 85%.   
     
     
         12 . A process of forming infusible, unidirectional fabric comprising:
 arranging a plurality of unidirectional fibers into a unidirectional fabric, wherein the unidirectional fibers are spaced uniformly within the unidirectional fabric;   forming an emulsion or suspension of a solvent, a bridging polymer, and a film-forming preventing agent, wherein the bridging polymer is dissolvable or dispersible in the solvent, wherein the film-forming preventing agent is dissolvable or dispersible;   applying the emulsion or suspension to the unidirectional fabric;   removing the solvent;   removing the film-forming preventing agent to form an infusible, unidirectional fabric, wherein the infusible, unidirectional fabric comprises:   a plurality of unidirectional fibers having a diameter and a length, wherein the unidirectional fibers are spaced uniformly in the unidirectional fabric;   a plurality of bridges, each bridge being connected to at least 2 unidirectional fibers and wherein at least 70% by number of fibers comprise at least one bridge connected thereto forming a bridged network of unidirectional fibers, wherein the bridges comprise a bridging polymer, wherein between the unidirectional fibers the bridges each have a width and a bridge width minimum, and wherein at least 50% by number of the bridges have a bridge width minimum less than about 2 millimeters; and,   a plurality of void spaces between the unidirectional fibers, wherein the void spaces are interconnected, wherein the fabric has a volume fraction of voids of between about 8 and 70%, wherein the fabric has a volume fraction of fibers of between about 35 and 85%.   
     
     
         13 . The process of  claim 12 , wherein the solvent is water. 
     
     
         14 . The process of  claim 12 , wherein the film-forming preventing agent is a liquid. 
     
     
         15 . The process of  claim 12 , further comprising infusing and curing a resin into the infusible, unidirectional fabric. 
     
     
         16 . The process of  claim 12 , wherein the infusible, unidirectional fabric does not comprises any stitching fibers or yarns. 
     
     
         17 . The process of  claim 12 , wherein the bridging polymer forms between about 0.1 and 30% of the effective cross-sectional area of the infusible, unidirectional fabric. 
     
     
         18 . A process of forming infusible, unidirectional fabric comprising:
 arranging a plurality of unidirectional fibers into a unidirectional fabric, wherein the unidirectional fibers are spaced uniformly within the unidirectional fabric;   forming an emulsion or suspension of a solvent, a bridging polymer, a blowing agent, a foaming agent and a gelling agent, wherein the bridging polymer is dissolvable or dispersible in the solvent;   applying the emulsion or suspension to the fabric;   activating the blowing agent forming bubbles in the emulsion and suspension, wherein the foaming agent and gelling agent stabilize the bubbles;   removing the solvent forming an infusible, unidirectional fabric, wherein the infusible, unidirectional fabric comprises:   a plurality of unidirectional fibers having a diameter and a length, wherein the unidirectional fibers are spaced uniformly in the unidirectional fabric;   a plurality of bridges, each bridge being connected to at least 2 unidirectional fibers and wherein at least 70% by number of fibers comprise at least one bridge connected thereto forming a bridged network of unidirectional fibers, wherein the bridges comprise a bridging polymer, wherein between the unidirectional fibers the bridges each have a width and a bridge width minimum, and wherein at least 50% by number of the bridges have a bridge width minimum less than about 2 millimeters; and,   a plurality of void spaces between the unidirectional fibers, wherein the void spaces are interconnected, wherein the fabric has a volume fraction of voids of between about 8 and 70%, wherein the fabric has a volume fraction of fibers of between about 35 and 85%.   
     
     
         19 . The process of  claim 18 , further comprising infusing and curing a resin into the infusible, unidirectional fabric. 
     
     
         20 . The process of  claim 18 , wherein the infusible, unidirectional fabric does not comprises any stitching fibers or yarns.