Multi-walled, sack-type packaging

Abstract

A multilayer packaging medium or sack has a filler opening, an impermeable outer layer, a porous inner layer, and an overlap region or fold having a perforated film between the inner and outer layers, with an open passage over a portion of the length of the folded area communicating with the perforated portion. The packaging medium is especially useful for the packaging of pulverulent materials, in particular water sensitive or water soluble powders.

1 - 8 . (canceled)  
     
     
         9 . A multilayer, sack-like packaging medium, comprising a front side and a rear side joined by first and second side areas, and closed at an upper end and a lower end, an opening for filling being free at the upper end, the packaging medium having an inner wall made of air-permeable material surrounded by an outer wall of air-impermeable material, wherein 
 a) on at least one of the front side and the rear side, the outer wall overlaps a subregion of up to 50% of the total area of the respective side,    b) in the overlap region, the inner layer of the outer wall is perforated,    c) at edges of the overlap region, the two layers lying one above the other are joined to each other by means of seams, forming a joint,    d) at one or both edges, the joint is interrupted over a continuous region which covers 10 to 50% of the total length of the joint,    e) 10 to 50% of the area of the overlap region is provided with perforations, and    f) a distance of 0.5 to 10 cm from the edges of the overlap region is maintained.    
     
     
         10 . The packaging medium of  claim 9 , wherein the outer wall overlaps only on the rear side.  
     
     
         11 . Packaging medium of  claim 9 , wherein the outer wall overlaps over its entire length.  
     
     
         12 . Packaging medium of  claim 10 , wherein the outer wall overlaps over its entire length.  
     
     
         13 . The packaging medium of  claim 9 , wherein the interruption is in the upper half of the packaging medium.  
     
     
         14 . The packaging medium of  claim 10 , wherein the interruption is in the upper half of the packaging medium.  
     
     
         15 . The packaging medium of  claim 11 , wherein the interruption is in the upper half of the packaging medium.  
     
     
         16 . The packaging medium of  claim 9 , wherein the inner wall comprises paper, woven material of synthetic fibers or natural fibers, or nonwoven materials made of synthetic fibres or natural fibres.  
     
     
         17 . The packaging medium of  claim 9 , wherein the air-impermeable outer walls comprise a plastic film.  
     
     
         18 . In the transport and storage of particulate materials, the improvement comprising transporting or storing said particulate materials in a storage medium if  claim 9 .  
     
     
         19 . The transport and storage of  claim 19 , wherein said particulate material includes at least one particulate material selected from the group consisting of polymer powders, redispersible polymer powders, highly disperse silica, cement, gypsum, as dry mortar, flour, animal feed, and water-soluble cement plasticizers and thickening agents.