Water soluble tooling materials for composite structures

Abstract

The present invention relates to a low density, water-soluble coring and tooling material used for the fabrication of composite parts. One aspect of the present invention relates to a lightweight, strong composite coring material that can be easily shaped and removed from cured composite parts. Another aspect of the present invention relates to a lightweight, strong composite tooling material that is easily tailored to provide a specific coefficient of thermal expansion and thermal conductivity, thus providing a tooling material that can be matched to the composite structure and material being fabricated.

1 . A method for manufacture of a mold core comprising: 
 (a) preparing a core composition having a polymer binder selected from the group consisting of polyvinylpyrrolidone, copolymers of polyvinylpyrrolidone, and combinations thereof;    (b) depositing the composition in a mold form for shaping the mold core; and    (c) drying the mold core to remove residual water.    
     
     
         2 . The method of  claim 1  further including the step of machining the mold core to provide a mold core having a predetermined shape.  
     
     
         3 . The method of  claim 1  further including the step of applying a finishing composition to an outer surface of the mold core to provide a smooth surface on the outer surface.  
     
     
         4 . The method of  claim 1 , wherein the finishing composition includes a polymer binder and a hardening compound.  
     
     
         5 . The method of  claim 4 , wherein the finishing composition has a viscosity between about 10 6  to about 10 7  cP and maintains its positioning on the surface where applied.  
     
     
         6 . The method of  claim 1  further including the step of forming a composite part on the mold core.  
     
     
         7 . The method of  claim 6  further including the step of removing the mold core from the composite part by solubilizing the mold core with a solvent.  
     
     
         8 . The method of  claim 7 , wherein the solvent includes water.  
     
     
         9 . The method of  claim 7 , wherein the mold core and composite part are cured before the mold core is removed.  
     
     
         10 . The method of  claim 9 , wherein the mold core and composite part are cured at temperatures of up to at least about 550° F.