Process of forming a infusible unidirectional fabric

Abstract

A process of forming infusible, unidirectional fabric containing the steps of arranging a plurality of unidirectional fibers into a unidirectional fabric, forming an emulsion or suspension of a solvent, a bridging polymer, and a film-forming preventing agent, applying the emulsion or suspension to the unidirectional fabric, removing the solvent, and removing the film-forming preventing agent to form an infusible, unidirectional fabric. The infusible, unidirectional fabric contains a plurality of unidirectional fibers, 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% and a volume fraction of fibers of between about 35 and 85.

What is claimed is: 
     
         1 . 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%.   
     
     
         2 . The process of  claim 1 , wherein the solvent is water. 
     
     
         3 . The process of  claim 1 , wherein the film-forming preventing agent is a liquid. 
     
     
         4 . The process of  claim 1 , further comprising infusing and curing a resin into the infusible, unidirectional fabric. 
     
     
         5 . The process of  claim 1 , wherein the infusible, unidirectional fabric does not comprises any stitching fibers or yarns. 
     
     
         6 . The process 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. 
     
     
         7 . The process of  claim 1 , wherein the film-forming preventing agent is sugar. 
     
     
         8 . The process of  claim 1 , wherein the unidirectional fibers comprise fiberglass fibers. 
     
     
         9 . 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%.   
     
     
         10 . The process of  claim 9 , further comprising infusing and curing a resin into the infusible, unidirectional fabric. 
     
     
         11 . The process of  claim 9 , wherein the infusible, unidirectional fabric does not comprises any stitching fibers or yarns. 
     
     
         12 . The process of  claim 9 , wherein the film-forming preventing agent is sugar. 
     
     
         13 . The process of  claim 9 , wherein the unidirectional fibers comprise fiberglass fibers.