Valve Bag

Abstract

The invention relates to a vented bag comprising a tubular vent that is secured in a folded base. Said vent comprises an upper face ( 4 ) that lies flat on a lower face ( 2 ) and consists of a base material that is provided with a weldable layer. The aim of the invention is to obtain a stable connection between the base material and the weldable layer. To achieve this, the weldable layer consists of a polyvinyl alcohol with a saponification degree ≧75%, which is applied to the base material in the form of an aqueous emulsion and is then dried.

1 . Valve bag with a tubular valve ( 1 ) fastened in a folded bottom, with an upper side ( 4 ) lying flat on a lower side ( 2 ) and comprised of a base material provided with a weldable layer, wherein the weldable layer is comprised of a polyvinyl alcohol with a saponification degree ≧75% applied in the form of an aqueous emulsion onto the base material and dried.  
   
   
       2 . Valve bag as claimed in  claim 1 , wherein between upper side ( 4 ) and lower side ( 2 ) a protective sheet ( 5 ) is inserted.  
   
   
       3 . Valve bag as claimed in  claim 2 , wherein the protective sheet ( 5 ) is comprised of two layers provided with a folding ( 8 ) directed toward the interior of the bag, and that the two layers ( 6 ,  7 ) of the protective sheet ( 5 ) are fastened on their free ends ( 9 ,  10 ) facing away from the folding ( 8 ) on the upper side ( 4 ) or the lower side ( 2 ) of the valve ( 1 ).  
   
   
       4 . Valve bag as claimed in  claim 1  wherein the base material is paper.  
   
   
       5 . Valve bag as claimed in  claim 1  wherein the saponification degree of the polyvinyl alcohol is ≧85%.  
   
   
       6 . Valve bag as claimed in  claim 5 , wherein the saponification degree of the polyvinyl alcohol is 88%.