Perpendicular perforation on zipper tape for air evacuation of package

Abstract

The plastic bags are provided with a web tape with a row of apertures which are cut parallel to each other, but perpendicular to the direction of travel of the row. The apertures are not colinear with one another. The apertures are sized to allow air to pass therethrough but not to allow selected solids to pass therethrough. These apertures are cut with a rotating wheel with teeth parallel to the axis of rotation and sized to provide the apertures of the desired size.

What is claimed is:  
     
         1 . A method for providing vent apertures to a web component of a plastic bag, comprising the steps of: 
 providing a cutting wheel which rotates about an axis, a periphery of said cutting wheel including teeth which are not perpendicular to said axis;    providing an anvil means against which said cutting wheel bears, thereby forming a nip; and    drawing the web component through said nip formed between said cutting wheel and said anvil means thereby forming apertures in the web component cut by said teeth.    
     
     
         2 . The method of  claim 1  wherein said teeth are parallel to said axis.  
     
     
         3 . The method of  claim 2  wherein said teeth are sized and spaced so as to form apertures which allow air to pass therethrough, but which do not allow selected solids to pass therethrough.  
     
     
         4 . The method of  claim 3  wherein said anvil means is a rotating wheel.  
     
     
         5 . The method of  claim 4  wherein said web component is a zipper tape.  
     
     
         6 . A plastic bag including walls and a mouth formed between said walls, at least one of said walls including a web component with a row of apertures which are not colinear with one another, said row of apertures being mechanically cut through said at least one wall.  
     
     
         7 . The plastic bag of  claim 6  wherein said apertures are parallel to each other, but perpendicular to a direction of travel of said row.  
     
     
         8 . The plastic bag of  claim 7  wherein said apertures are sized to allow air to pass therethrough, but not to allow selected solids to pass therethrough.  
     
     
         9 . The plastic bag of  claim 8  wherein said web component is a zipper tape.  
     
     
         10 . The plastic bag of  claim 6  wherein both of said walls include said web component with said row of said apertures.