Side-gusset bag made of a plastic film/fabric laminate

Abstract

A side-gusset bag has a front panel, a rear panel, and side gussets between the front panel and the rear panel and connected to the front panel and rear panel by edge folds. The plastic film/fabric laminate has a polymer film on an outer surface of the bag and a fabric connected to the polymer film and made of polymer ribbons on an inner surface of the bag. A flap of the front panel and side gusset flaps between the flap of the front panel and the rear panel are folded onto the rear panel to form a bottom gusset to which they are connected. Corner weld seams bond the fabric surfaces of the side gussets on the inner surface of the bag to the adjacent fabric surfaces of the front panel or rear panel and an acute angle toward the bottom gusset.

We claim: 
     
         1 . In a side-gusset bag made of a plastic film/fabric laminate, having
 a front panel;   a rear panel; and   side gussets between the front panel and the rear panel and connected to the front panel and rear panel by edge folds, where   the plastic film/fabric laminate has a polymer film on an outer surface of the bag and a fabric connected to the polymer film and made of polymer ribbons on an inner surface of the bag, and   a flap of the front panel and side gusset flaps between the flap of the front panel and the rear panel are folded onto the rear panel to form a bottom gusset to which they are connected,   
       the improvement comprising:
 corner weld seams bonding the fabric surfaces of the side gussets on the inner surface of the bag to the adjacent fabric surfaces of the front panel or rear panel and extending at an acute angle toward the bottom gusset, the corner weld seams having a structure with a grid pattern made of a plurality of punctiform or linear weld points, the structure being generated by ultrasound welding. 
 
     
     
         2 . The side-gusset bag defined in  claim 1 , wherein the structure of the corner weld seam generated by ultrasound welding has a grid pattern of a two-dimensional array of weld points behind and adjacent one another. 
     
     
         3 . The side-gusset bag defined in  claim 1 , wherein the corner weld seams extend to the bottom gusset or near to the bottom gusset. 
     
     
         4 . The side-gusset bag defined in  claim 1 , wherein the corner weld seams together with the bottom gusset and one edge fold on the side enclose equilaterally triangular regions. 
     
     
         5 . The side-gusset bag defined in  claim 1 , wherein
 a ventilation hole is in at least one triangular bag flap bounded by a corner weld seam, and   an exchange of air is ensured between the bag flap configured with the ventilation hole and the fill space of the side-gusset bag.   
     
     
         6 . The side-gusset bag defined in  claim 1 , wherein the fabric consists of a mesh of the polymer ribbons. 
     
     
         7 . The side-gusset bag defined in  claim 6 , wherein the polymer ribbons of the mesh have a width between 2 mm and 5 mm in the longitudinal warp direction of the bag and in the transverse weft direction of the bag. 
     
     
         8 . The side-gusset bag defined in  claim 6 , wherein the polymer ribbons of the mesh extending longitudinally of the bag and polymer ribbons extending transversely of the bag have substantially the same width. 
     
     
         9 . The side-gusset bag defined in  claim 1 , wherein the corner weld seams have a width between 2 mm and 10 mm, the grid pattern having 10 to 500 weld points per surface area of 100 mm 2 . 
     
     
         10 . The side-gusset bag defined in  claims 1  to  9 , wherein
 the weld points of the corner weld seams are arrayed in parallel lines oriented at an angle of 45° with respect to a longitudinal extension of the corner weld seams, and 
 at least three weld points are on each line at equidistant spacings next to each other. 
 
     
     
         11 . The side-gusset bag defined in  claim 1 , wherein a lower edge of the front panel, a lower edge of flanks of the side gussets adjacent the front panel, a lower edge of flanks of the side gussets adjacent the rear panel, and a lower edge of the rear panel are offset with respect to each other in a fan shape such that the layers of the plastic film/fabric laminate folded along the bottom gusset each have a flap that directly abuts the rear panel and is glued to the rear panel.