Method for the production of a flexible bulk-material container and bulk-material container produced according to said method

Abstract

The invention relates to a flexible bulk-material container made of at least one woven blank of a synthetic strip-type material and to a method for the production thereof. In the seam areas ( 25 ),the woven blank ( 20.1 ) is provided with an overlapping or another woven blank ( 20.2 ) placed on top. An energy conversion agent 924 ) is inserted into the boundary layer ( 22 ) which is disposed between the overlapping and/or woven blanks placed on top ( 20.1, 20.2 ). The woven blank or blanks ( 20.1, 20.2 ) is/are melted by means of laser beams acting upon the energy conversion agent ( 24 ).

1 . Method for producing a flexible bulk-goods container from a plastic strip fabric comprising the following steps: 
 a) introducing of the energy of a laser beam with an energy-conversion medium that absorbs wavelength λ 1  and converts it into thermal energy into a seam area of at least one cut-fabric section, the cut fabric section comprising a plastic that is light permeable to the laser beam;    b) producing an overlap of the cut-fabric section in a seam area thereby forming a boundary layer between the overlapping fabric layers;    c) penetrating at least one of the fabric layers with a laser beam having a wavelength of λ 1  in the seam area;    d) allowing partial melting of the fabric layers in their surface area under formation of a weld seam location as a homogeneous bond between the fabric layers ( 20 . 1 ,  20 . 2 ); and    e) repeating steps b) through d) until all seam areas are welded.    
     
     
         2 . Method as defined in  claim 1 , wherein the energy-conversion medium is impressed onto at least one of the fabric layers.  
     
     
         3 . Method as defined in  claim 2 , wherein the energy-conversion medium is impressed onto the seam area.  
     
     
         4 . Method as defined in  claim 2 , wherein the energy-conversion medium is impressed onto the entire area.  
     
     
         5 . Method as defined in  claim 1 , wherein the energy-conversion medium is inserted between the fabric layers in the form of a light-energy-absorbing welding film.  
     
     
         6 . Method as defined in  claim 1 , wherein the energy-conversion medium is mixed into the plastic of at least one of the fabric layers.  
     
     
         7 . Method as defined in  claim 1 , wherein a first cut-fabric section is welded into a cylinder that is welded to a second cut-fabric section as a floor section.  
     
     
         8 . Method as defined in  claim 1 , wherein a first cut-fabric section is welded into a cylinder, and wherein a floor section is formed by multiple folding and repositioning of partial areas of the cut-fabric section, whereby the folds are fixed by laser beam welding.  
     
     
         9 . Method as defined in  claim 8 , wherein a floor and/or roof area is formed using the following process steps: 
 a) folding the cylindrical cut fabric section flat into a two-layer flat piece;    b) producing a first fold mark on both fabric layers over the entire width of the flat piece at a distance to the lower edge corresponding to half the width of the flat piece;    c) producing a second and third fold mark starting from the center of the lower edge to each cutting point of the first fold mark with a side edge of the flat piece;    d) inserting a first and second side-edge section that extends between the lower edge and the first fold mark into the interior of the two-layer flat piece by folding the fabric along the second and third fold marks up to the overlay of the side-edge sections on the first fold mark in the interior of the two-layer fabric;    e) folding the triangular sections thus formed and overlaying the corners into the area of the first fold mark; and    f) affixing the triangular sections and/or by penetrating laser-beam welding of the seam areas.    
     
     
         10 . Method as defined in  claim 1 , wherein at least one cut fabric section is formed by corner extraction of two asymmetrical, mirror-reflected along one edge trapezoidal sections, whereby the cut fabric section thus obtained includes at least: 
 a rectangular sidewall area;    a trapezoid-shaped floor or roof area adjacent to the sidewall area; and    a rectangular reinforcement area adjacent to each floor and/or roof area whose sidewall, floor, roof, and/or reinforcement areas each are welded in edge seam areas.    
     
     
         11 . A flexible bulk goods container comprising at least one cut fabric section made of plastic fabric band, wherein the cut fabric section overlaps in the seam areas or is provided with an additional cut fabric section laid on it, and wherein an energy-conversion medium is inserted into the border layer, and the cut fabric sections is/are melted by laser beams acting on the energy-conversion medium(s).  
     
     
         12 . A flexible bulk goods container as defined in  claim 12 , further comprising a surrounding sidewall and at least one floor section and/or roof section wherein the sidewall and floor section and/or roof section is/are formed of the same cut fabric section, and wherein the seam areas of the cut fabric section are formed in the seam areas overlapping with the energy-conversion medium inserted into the intermediary border layer, and is melted by the laser beams ( 11 ,  11 ′) acting on the energy conversion medium.  
     
     
         13 . A flexible bulk goods container as defined in  claim 12 , wherein the floor section and/or roof section includes a round recess that is formed by means of quarter-circle shaped recesses near at least two corners of the cut fabric section that has been folded into a flat piece, and by at least one half-circle recess positioned in the center of an open edge of the flat piece.  
     
     
         14 . A flexible bulk goods container as defined in  claim 12 , further comprising at least one surrounding sidewall and at least one floor or roof section, and by four cut fabric sections that are welded at seam areas near the edges, wherein each cut fabric section includes at least: 
 a rectangular sidewall area;    a trapezoid-shaped floor or roof area adjacent to the sidewall area; and    a rectangular reinforcement area adjacent to each floor and/or roof area.    
     
     
         15 . A flexible bulk goods container as defined in  claim 10 , wherein at least one carrying handle is positioned on the sidewall that is connected to it by means of a separate finger-shaped welding flap.  
     
     
         16 . A flexible bulk goods container as defined in  claim 10 , wherein the cut fabric section is at least partially provided with micro-perforations that are spot-melted by laser beams.  
     
     
         17 . Method as defined in  claim 1 , wherein the cut-fabric section comprises a stretched tubular fabric, and wherein a floor section is formed by multiple folding and repositioning of partial areas of the cut-fabric section, whereby the folds are fixed by laser beam welding.