Thermally conductive resin article for food contact and food processing and method for manufacturing same

Abstract

A method of making a net-shape molded article for use with food processing and food contact is disclosed. The article is made from a molten resin including a polypropylene base matrix loaded with a thermally conductive filler such that the molten resin has a thermal conductivity between about 1.0 W/mK and about 20 W/mK when fully set. The molten resin is formed into an article, such as a food tray, using injection molding techniques. Preferably, the thermally conductive material includes hexagonal boron nitride and natural graphite.

1 . A thermally conductive resin for use with food processing and food contact, consisting essentially of: 
 a polypropylene base matrix;    a thermally conductive filler loaded into the polypropylene base matrix;    said resin having a thermal conductivity between about 1.0 W/mK and about 20 W/mK.    
   
   
       2 . The resin of  claim 1 , wherein said thermally conductive filler comprises a mixture of hBN and natural graphite.  
   
   
       3 . The resin of  claim 1 , wherein said resin had a thermal conductivity between about 2.0 W/mK and about 10 W/mK.  
   
   
       4 . The resin of  claim 1 , wherein said thermally conductive filler comprises about 5 to about 70 weight percent of said resin.  
   
   
       5 . The resin of  claim 1 , wherein said thermally conductive filler comprises about 20 to about 50 weight percent of said resin.  
   
   
       6 . A thermally conductive food tray, comprising: 
 a tray body having a bottom wall bounded by at least one side wall defining a food containing portion therein;    said tray body, net-shape molded from a resin, consisting essentially of: 
 a polypropylene base matrix;  
 a thermally conductive filler loaded into the polypropylene base matrix;  
   said resin having a thermal conductivity between about 1.0 W/mK and about 20 W/mK.    
   
   
       7 . The tray of  claim 6 , wherein said thermally conductive filler comprises a mixture of hBN and natural graphite.  
   
   
       8 . The tray of  claim 6 , wherein said resin had a thermal conductivity between about 2.0 W/mK and about 10 W/mK.  
   
   
       9 . The tray of  claim 6 , wherein said thermally conductive filler comprises about 5 to about 70 weight percent of said resin.  
   
   
       10 . The tray of  claim 6 , wherein said thermally conductive filler comprises about 20 to about 50 weight percent of said resin.  
   
   
       11 . The tray of  claim 6 , further comprising a plurality of surface area enhancements.  
   
   
       12 . The tray of  claim 11 , where said plurality of surface area enhancements are a number of spaced-apart parallel grooves.  
   
   
       13 . A method of making a net-shape molded article for use with food processing and food contact, comprising the steps of: 
 providing a mold press having a mold cavity;    providing a molten resin consisting essentially of 
 a polypropylene base matrix; and  
 a thermally conductive filler loaded into the polypropylene base matrix;  
   said molten resin having a thermal conductivity between about 1.0 W/mK and about 20 W/mK when fully set; and    injecting said molten resin into the mold cavity of the mold press to form said net-shape molded article.    
   
   
       14 . The method of  claim 13 , wherein said thermally conductive filler comprises a mixture of hBN and natural graphite.  
   
   
       15 . The method of  claim 13 , wherein said resin had a thermal conductivity between about 2.0 W/mK and about 10 W/mK.  
   
   
       16 . The method of  claim 13 , wherein said thermally conductive filler comprises about 5 to about 70 weight percent of said resin.  
   
   
       17 . The method of  claim 13 , wherein said thermally conductive filler comprises about 20 to about 50 weight percent of said resin.