Methods for making multi-layered plastic end products

Abstract

The present invention generally relates to systems and methods for generating, processing, handling and forming plastic materials into an end product such as, but not limited to, consumables and packaging. The plastic materials are made into preforms or preform sheets, which in turn may be selectively masked to expose desired regions of the same for a saturation process, a heating process, or both. In addition, the various processes may be sufficiently controlled to obtain a desired micro-structure, and in turn obtain desired mechanical, structural, and aesthetic properties in the end product. By way of example, an embodiment of the present invention results in consumable, plastic cups that are lighter weight and more structurally robust less than conventional plastic cups. Further to one or more embodiments of the present invention, various systems for material handling may be utilized to efficiently, timely and cost effectively produce the preforms.

1 . A method for making plastic end products, the method comprising:
 generating a plurality of plastic preforms, each preform having a inner region defining an area from which an end product will be formed, and each inner region bounded by a periphery region;   loading the plurality of preforms into a pressure vessel rack;   placing the pressure vessel rack into a pressure vessel;   applying a pressure to the pressure vessel rack;   while under pressure, saturating the plurality of preforms with a gas for a predetermined sorption time;   moving the plurality of preforms from the pressure vessel rack into a heating rack;   heating the plurality of preforms; and   forming each of the plurality of preforms into a configuration corresponding to a desired plastic end product.   
     
     
         2 . The method of  claim 1 , further comprising selectively constraining the periphery regions of the preforms during heating. 
     
     
         3 . The method of  claim 1 , wherein generating the plurality of plastic preforms includes cutting the preforms from a sheet of plastic material. 
     
     
         4 . The method of  claim 1 , wherein generating the plurality of plastic preforms includes injection molding the preforms. 
     
     
         5 . The method of  claim 1 , wherein the inner region is a first shape and the periphery region is a second shape. 
     
     
         6 . The method of  claim 5 , wherein the first shape is different from the periphery shape. 
     
     
         7 . The method of  claim 1 , wherein loading the plurality of preforms into the pressure vessel rack includes spacing the preforms from each other by a predetermined distance defined by receiving slots formed in the pressure vessel rack. 
     
     
         8 . The method of  claim 1 , wherein saturating the plurality of preforms with the gas includes saturating the plurality of preforms with carbon dioxide. 
     
     
         9 . The method of  claim 1 , wherein saturating the plurality of preforms with the gas includes partial-pressure saturating the plurality of preforms to generate a layered micro-structure. 
     
     
         10 . The method of  claim 1 , wherein saturating the plurality of preforms with the gas for the predetermined sorption time includes predetermining the sorption time to be in a range of about one minute to about 2,400 minutes. 
     
     
         11 . The method of  claim 1 , wherein saturating the plurality of preforms with the gas includes masking the periphery regions to reduce an amount of gas sorption by the periphery regions as compared to the inner regions. 
     
     
         12 . The method of  claim 1 , further comprising controlling an amount of desorption time to vary a density throughout the preform. 
     
     
         13 . The method of  claim 1 , further comprising controlling a temperature with the pressure vessel. 
     
     
         14 . The method of  claim 1 , wherein forming each of the plurality of preforms into the configuration includes advancing forming plugs onto the preforms during heating. 
     
     
         15 . The method of  claim 14 , further comprising controlling a temperature of the forming plugs. 
     
     
         16 . The method of  claim 1 , wherein forming each of the plurality of preforms into the configuration includes advancing forming plugs onto the preforms after heating. 
     
     
         17 . The method of  claim 16 , further comprising controlling a temperature of the forming plugs. 
     
     
         18 . The method of  claim 1 , wherein forming each of the plurality of preforms into the configuration includes forming the preforms using air pressure selectively applied to the preforms. 
     
     
         19 . A cross-sectional micro-structure of a plastic apparatus comprising:
 an exterior surface;   an interior surface;   a first intermediate region located between the exterior and interior surface, the first intermediate region configured with a plurality of first foamed cells, wherein the first foamed cells include a plurality of first interstices disposed among a plurality of first plasticized portions; and   a second intermediate region located between the exterior and interior surface, the second intermediate region configured with a plurality of second foamed cells, wherein the second foamed cells include a plurality of second interstices disposed among a plurality of second plasticized portions, and wherein the second interstices are larger than the first interstices.   
     
     
         20 . The cross-sectional structure of  claim 19 , further comprising an intermediate wall located between the first intermediate region and the second intermediate region. 
     
     
         21 . The cross-sectional structure of  claim 20 , wherein the intermediate wall is generally a solid wall. 
     
     
         22 . The cross-sectional structure of  claim 19 , wherein the first intermediate region includes a first density that is higher than a second density of the second intermediate region. 
     
     
         23 . The cross-sectional structure of  claim 19 , wherein the exterior surface is generally a solid surface. 
     
     
         24 . The cross-sectional structure of  claim 19 , wherein the interior surface is generally a solid surface. 
     
     
         25 . The cross-sectional structure of  claim 19 , further comprising a third intermediate region located between the exterior and interior surface, wherein the third intermediate region is configured with a plurality of third foamed cells, wherein the third foamed cells include a plurality of third interstices disposed among a plurality of third plasticized portions, and wherein the third intermediate region includes a third density that is greater than, lesser than, approximately equal to, or equal to one of either a first density of the first intermediate region or a second density of the second intermediate region.