Patent ID: 6142302
Filing Date: 2000-11-07
Classification: B31B,B65D

Abstract:
A method of making a stack of self-opening, side-sealed bags of low density polyethylene, where each of said bags has front and rear walls of a predetermined width and where the height of the front wall of each bag is less than the height of the back wall of each bag, comprising:(a) moving flattened low density polyethylene tube material through a bag making machine with the side of the flattened tube material which will form the front wall of each bag facing upward;(b) depositing dots of glue on the upward-facing side of the flattened tube material as it moves through the bag making machine, the spacing between sequential dots being equal to the predetermined width of the bag and the location of each dot being below the top of the front wall of the bag;(c) reducing the temperature of each dot of glue as it is deposited;(d) cutting the polyethylene roll to the predetermined width for the bag and sealing the sides of the bag so that the dot of glue on the back of each bag is substantially equidistant from the two sides of the bag;(e) stacking a predetermined number of bags on top of and in registration with each other;(f) simultaneously perforating all bags in a stack by passing a serration tool through the stack, the perforations defining the top of the back wall of each bag; and(g) hot welding the back walls of the bags in a stack together by passing two hot needles through the back walls in the space between the tops of the back and front walls, the holes in the stack formed by the needles being spaced from and on opposite sides of the centerline of the stack of bags.