Block bottom bag
AssigneeStandard Multiwall Bag Manufacturing Co.
InventorYuming Pang
Life of this patent
Estimating the term…
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.
Claims20
A block bottom bag for containing bulk quantities of material, comprising:
- a tubular body having an open end and a closed end to define a bag having an interior surface, said body defining a longitudinal bag axis and comprising multiple plies of paper including an innermost paper ply and a ply of plastic glued to said innermost paper ply and non-detachable therefrom, each of said paper plies having opposite lateral side edges overlapped along the bag axis and adhered to one another to define offset longitudinal seams and said plastic layer having opposite lateral side edges overlapped and sealed, and said body further comprising a front panel and a back panel;
- wherein said interior surface is substantially entirely covered with said plastic and substantially free from exposed paper.
A blank for forming a block bottom bag, comprising:
- multiple paper layers, each layer adhered to the next adjacent layer to define a top layer and a bottom layer;
- at least one plastic layer adhered to the top paper layer and non-detachable therefrom;
- said multiple layers of paper and plastic defining a generally rectangular blank having a longitudinal bag axis, wherein each layer of paper and plastic has opposed side edges and opposed end edges;
- a pair of fold lines extending along said longitudinal bag axis to define a front panel and a back panel;
- wherein the end edge of each layer is offset relative to the end edge of the next adjacent layer in the back panel, and the end edges of each layer are coextensive in the front panel.
A method of forming a block bottom bag, comprising the steps of:
- (a) forming a flat and generally rectangular bag blank from multiple paper layers, each layer adhered to the next adjacent layer to define a top layer and a bottom layer and adhering a plastic layer to the top paper layer so that the plastic layer is non-detachable therefrom, said bag blank having opposed side edges and opposed end edges and defining a longitudinal bag axis extending between said opposed end edges;
- (b) forming a pair of parallel fold lines extending between said opposed end edges;
- (c) folding said bag blank along said parallel fold lines and overlapping and adhering to one another the respective side edges of each layer to form a tubular member having open opposite ends;
- (d) closing one of said open ends by folding said layers inwardly to define an inner bag surface that is substantially entirely covered with said plastic and substantially free from exposed paper.
Dependencies are inferred from the claim text.