Pattern bonding of webs by electron beam curing

A method of manufacturing a satchel type square bottom bag from an elongated web of bag forming material having a sufficient length to provide a plurality of bag forming lengths serially connected along transverse cut lines, said lengths each having a bottom wall forming portion located centrally of and extending longitudinally of the web and a pair of side wall forming portions projecting laterally one on either side of the bottom wall forming portion, said bottom wall portion having a central gusset fold line located centrally and extending longitudinally thereof and dividing the bottom wall portion into two bottom gusset panels, and a side gusset fold line connecting each bottom gusset panel to an adjacent side wall forming portion and extending parallel to the central gusset fold line comprising the steps of:

• (a) continously driving a web through a printing device in a flat unfolded configuration, the printing device being operable to apply an E.B. curable coating in a predetermined pattern to selected portions of an inner face of said web, said selected portions comprising,
• (i) a plurality of transversely extending longitudinally spaced bands each having a diamond shaped portion centered at the intersection of the transverse cut line and each side gusset fold line and a narrow portion extending laterally from each diamond shaped portion to an adjacent side edge of the web on each side of each cut line,
• (b) folding the web upon itself along the central and side gusset fold lines to locate the bottom gusset panels in a face-to-face relationship with their associated side wall forming portions and the remaining uncovered portions of the side wall forming portions in a face-to-face relationship with respect to one another,
• (c) continuously driving the folded web through an E.B. radiation device to radiate the web and thereby bond the coated areas at their interface,
• (d) severing the bag forming lengths from the web by cutting the web along said transverse cut lines to provide bags which have a bottom wall which can unfold along the bottom and side gusset fold lines to form a square bottom.

A method of making a satchell type square bottom bag having a gusset extending along the bottom edge thereof and a pair of side seams extending normal to the bottom edge, said gusset being formed by a central fold line and a pair of spaced parallel side fold lines, said bag being formed from a continuous web of bag forming material comprising the steps of:

• (a) continuously driving said web through a printing device in the flat unfolded configuration, the printing device being operable to apply an E.B. curable coating in a predetermined pattern to selected portions of an inner face of said web, said selected portions comprising:
• (i) a plurality of longitudinally spaced transversely extending portions, said transversely extending portions including side seam forming portions and first and second bottom corner forming portions extending longitudinally from each side seam forming portion to meet one another at the central fold line, said first and second bottom corner forming portions having first and second sections arranged on opposite sides of their associated side fold line,
• (b) folding the web upon itself along the central gusset fold line and the side fold lines to dispose the central fold line inwardly from the side fold lines with the side seam forming portions arranged in a face-to-face relationship to form a bondable interface therebetween, the first corner forming portions and the second corner forming portions being arranged with their first sections disposed in a face-to-face relationship with their second sections to form second and third bondable interfaces,
• (c) continuously driving the folded web through an E.B. radiation device to radiate the web and thereby bond the coated areas at bondable interfaces,
• (d) transversely severing the web along transversely extending bonded seal lines to separate individual bags from said web.