Filters made from chemical binders and microspheres

Abstract

This invention relates to filters made from a refractory material, preferably an insulating material, and chemical binder. The filters are used in the foundry industry to filter molten metal. The invention also relates to a process for preparing the filters.

1 - 6 . (canceled)  
   
   
       7 . A process for preparing a filter comprising: 
 (a) forming a mix comprising a refractory material and an effective bonding amount of a foundry binder,    (b) shaping said mix to form a shape, such that shape contains openings through which molten metal can pass; and    (c) curing said shape.    
   
   
       8 . The process of  claim 7  wherein the process is a cold-box process comprising: 
 (a) forming a mix comprising a refractory material and an effective bonding amount of a foundry binder,    (b) shaping said mix to form a shape, such that shape contains openings through which molten metal can pass; and    (c) curing said shape with a gaseous curing catalyst.    
   
   
       9 . The process of  claim 8  wherein the refractory is an insulating material comprises ceramic microspheres.  
   
   
       10 . The process of  claim 9  wherein the binder is a phenolic urethane binder and the catalyst is triethylamine.  
   
   
       11 . A no-bake process for preparing a filter comprising: 
 (a) forming a mix comprising a refractory material, an effective bonding amount of a foundry binder, and a liquid curing catalyst; and    (b) shaping said mix to form a shape, such that shape contains openings through which molten metal can pass.    
   
   
       12 . The process of  claim 11  wherein the refractory material is an insulating material comprising ceramic microspheres.  
   
   
       13 . The process of  claim 12  wherein the binder is a phenolic urethane binder and the catalyst is a liquid tertiary amine.  
   
   
       14 . A filter prepared by the process of claim  6 ,  7 ,  8 ,  9 ,  10 ,  11 ,  12 , or  13 .  
   
   
       15 . A process for casting a metal part which comprises: 
 (a) inserting the filter of claim  1 ,  2 ,  3 ,  4 ,  5 , or  6  into a pouring cup or directly in a sprue of a mold assembly;    (b) manufacturing the filter as an integral part of the pouring cup or mold assembly    (b) pouring metal, while in the liquid state, through said filter;    (c) allowing said metal to cool and solidify; and    (d) then separating the cast metal part from the casting assembly.    
   
   
       16 . The filter of  claim 14  which is shaped such that it has an entrance means and exit means.  
   
   
       17 . The filter of  claim 14  wherein the exit means is flat.  
   
   
       18 . The filter of  claim 14  wherein the exit means is concave.  
   
   
       19 . The filter of claim  5  wherein the exit means is convex.