Cooling of extruded and compression molded materials

Abstract

The present invention relates to a system and a method for cooling extruded and molded materials. The present invention is especially useful to thoroughly cool an extrudate by directing a cooling fluid toward a surface of the extrudate (e.g., an interior surface that defines a hollow portion of an extrudate). Hollows may be created in order to reduce material, weight, and/or processing time. A cooling fluid is diverted toward the surface of the extrudate so as to cool the material and assist in solidification. A baffle may serve to divert the cooling fluid in the desired direction. In another example, the extrudate may be partially or totally immersed in a liquid cryogenic fluid. Increases in production line throughput may result by rapidly cooling the molded material. In addition, the more efficient cooling may be achieved with a lesser amount of the cooling fluid, and the velocity and temperature of the cooling fluid may be reduced. Other uses for the present invention include injection molding, compression molding, gas assist molding, and co-extrusion.

1 - 20 . (canceled)  
   
   
       21 . A method for cooling a product made from a material, said method comprising: 
 forcing said material through a die;    directing a cryogenic fluid through said die, said cryogenic fluid having a temperature below about −250 degrees Fahrenheit; and    subjecting said material to said cryogenic fluid as said material exits said die.    
   
   
       22 . (canceled)  
   
   
       23 . The method of  claim 21  wherein said cryogenic fluid is selected from liquid oxygen, liquid nitrogen, liquid neon, liquid hydrogen, and liquid helium.  
   
   
       24 . The method of  claim 21  wherein said cryogenic fluid is liquid.  
   
   
       25 . The method of  claim 21  wherein said cryogenic fluid is vapor.  
   
   
       26 . The method of  claim 21  wherein said cryogenic fluid is gas.  
   
   
       27 . The method of  claim 21  wherein: 
 said product has an interior surface; and    said interior surface is subjected to said cryogenic fluid.    
   
   
       28 . The method of  claim 27  wherein said interior surface defines a hollow.  
   
   
       29 . The method of  claim 21  wherein an exterior surface of said product is subjected to said cryogenic fluid.  
   
   
       30 . The method of  claim 21  wherein said material is forced through said die by extrusion.  
   
   
       31 . The method of  claim 21  wherein said material is a cellulosic/polymer composite.  
   
   
       32 . A method of cooling a product having a hollow portion, said method comprising: 
 directing a cryogenic fluid through a die, said cryogenic fluid having a temperature below about −250 degrees Fahrenheit; and    subjecting said hollow portion to said cryogenic fluid as said product exits said die.    
   
   
       33 . (canceled)  
   
   
       34 . The method of  claim 32  wherein said cryogenic fluid is selected from liquid oxygen, liquid nitrogen, liquid neon, liquid hydrogen, and liquid helium.  
   
   
       35 . The method of  claim 32  wherein said cryogenic fluid is liquid.  
   
   
       36 . The method of  claim 32  wherein said cryogenic fluid is vapor.  
   
   
       37 . The method of  claim 32  wherein said cryogenic fluid is gas.  
   
   
       38 . The method of  claim 32  further comprising subjecting an exterior surface of said product to said cryogenic fluid.  
   
   
       39 . The method of  claim 32  further comprising forcing said product out of said die by extrusion.  
   
   
       40 . The method of  claim 32  wherein said product is made from a cellulosic/polymer composite.