Article employing expanded thermoplastic elements and methods for making same

Abstract

A drainage element is made by filling a container with expanded thermoplastic elements that are in a non-cured state and that possess a degree of latent foaming ability. After filling the container with the non-cured elements, the elements are allowed to cure under ambient conditions during which the blowing agent remaining in the elements in a vapor state condenses allowing air to be drawn in while the elements expand. This expansion of the elements distends and rigidifies the container where the container is allowed to expand

1 . A drainage element comprising
 a tubular netting having a pair of closed ends; and   a mass of expanded loose fill discrete elements within said netting characterized in having been expanded from an initial state to an expanded state after filling of said netting therewith and in imparting a degree of rigidity to the drainage element in said expanded shape sufficient to maintain an expanded three dimensional shape of said netting.   
   
   
       2 . A drainage element as set forth in  claim 1  further comprising a pipe passing through said mass of elements and extending outwardly of said closed ends of said netting. 
   
   
       3 . A drainage element as set forth in  claim 2  wherein said pipe is perforated. 
   
   
       4 . A drainage element as set forth in  claim 2  wherein said pipe is corrugated. 
   
   
       5 . A drainage element as set forth in  claim 1  wherein said loose fill elements have a bulk density of less than 1.0 pounds per cubic foot. 
   
   
       6 . A drainage element as set forth in  claim 1  having a length of ten feet, a diameter of ten inches, and a degree of rigidity characterized in that when supported in a horizontal plane at a mid-point with at least one end extending therefrom in a cantilever manner, said one end has a deflection of two inches or less relative to said horizontal plane. 
   
   
       7 . A drainage element comprising
 a container of flexible material characterized in having been expanded from a collapsed state into an expanded three dimensional shape; and   a mass of expanded loose fill discrete thermoplastic elements within said container characterized in having been placed in said container in a non-cured expanded initial state and thereafter expanded from said initial state to a further expanded cured state without external manipulation while in said container and in imparting a degree of rigidity to said container in said expanded shape thereof sufficient to maintain said expanded three dimensional shape of said container.   
   
   
       8 . A drainage element as set forth in  claim 7  wherein said container is a tube made of plastic flexible screen.