Block bottom bag

Abstract

A block bottom bulk material bag, or satchel bottom bag, is formed from multiple plies of paper and an inner ply of plastic that is adhered to the innermost ply of paper. The bag is formed from roll-stock material that is cut into blanks. The knives that cut the blanks are registered relative to one another so that when the pinch bottom or satchel bottom is formed there is no paper surface exposed to the interior of the bag and the entire interior surface of the bag to which bulk material contained in the bag is exposed is covered with plastic.

I claim:  
     
         1 . In a block bottom bag of the type having a tubular body with an open end and a closed block bottom end to define a bag having an interior surface, the body comprising multiple plies of paper including an innermost paper ply and a ply of plastic interiorly of the innermost paper ply, each of the paper plies having opposite side edges adhered to one another and the plastic ply having opposite side edges sealed to one another, and the body further having a front panel and a back panel, opposite side edges and opposed top and bottom edges to define opposed bottom corners, wherein the open end is defined by the respective top edges of the front and back panels and the top edge of the back panel extends beyond the top edge of the front panel, the improvement comprising: 
 in the front panel the outermost paper ply includes an extended segment extending across a portion of the front panel at the bottom edge, and the block bottom end is formed by folding the opposed bottom corners inwardly at a pair of diagonal fold lines, each of which extends diagonally from a respective side edge to the bottom edge to thereby define an opening at the bottom of said bag and a front flap and a back flap, wherein the opening is a regular rectangle having opposed side edges and upper and lower edges, the opening having a front flap portion and a back flap portion, wherein the side edges of all paper plies and plastic in the front flap portion of the opening are coextensive, and the side edges of plastic in the back flap portion of the opening are aligned with the side edges of the opening in the front flap portion but the edges of at least one paper ply in the back flap portion are stepped outwardly relative to the edges of the plastic in said back flap portion.