Abstract: In a popcorn package for microwave popping, the subsequent popping of popcorn by microwave energy is enhanced by the use of a layer of metallized ink printed on the bag of a popcorn package. The metallized ink contains powdered aluminum and is of a commercial grade but diluted to provide an opacity level of light transmission in the range of 47% to 10%, such layer lying below the charge of popcorn and shortening during popping. The material of the bag comprises a pair of plies with the layer of metallized ink being printed to one of the plies and disposed between the plies of the bag.

Abstract: In making a tubular bag, a first band of thermosetting glue is printed across the length of a web, and a second and third band of such glue is printed on the opposite side of the web in registry with the ends of the first band. The printed glue is then dried with a heat below that of the softening temperature of the thermosetting glue. Glue is applied to a marginal edge of the web and the marginal edges are overlapped and thus glued together as a back seam. An increment of the tube is severed at said bands without heating such bands, and the web is folded along a line extending centrally through the glue bands. The bands are simultaneously clamped together and heated to fuse the bag layers together at the bands.

Abstract: A tubular web has a bottom which is tightly sealed to enable pressurizing of the bag, the bottom including a first band of thermosetting glue imprinted across the length of the web at the interior of the tube. A second band and a third band of thermosetting glue are imprinted on the tube at the exterior thereof in registry with the ends of the first band and jointly extend across a rear panel. The tube has a turned up bottom defined by a fold along a line extending centrally along the imprinted bands, each portion of the thermosetting glue bands being thermally fused only to other portions of such bands in contact therewith. In one embodiment, there is a second fold along a second line spaced from the turned up bottom which defines an area between the second line and the turned up bottom, such area being joined by glue to the back panel.