In a blank for folding into a parallelepipedal package that is intended for liquids, the blank having an area that is to be folded into a double-M closure for a gable-shape top having inwardly folded opposite triangular sections and a middle fold line, the improvement which comprises providing each of said opposite triangular sections with a slit that slants from the upper edge down to or slightly beyond the middle fold line, whereby the folded package has an improved seal. When the cross-section is square, the slits should be parallel so that the folded areas dogleg and overlap.

The present invention includes of a method for producing a cross sectionally tetragonal tube package for flowable substances, in particular milk and juices. A carrier material (12) coated with synthetic plastic is cut longitudinally and horizontally through to center (35) and then shaped to form two welds (13,14) which made up the relevant tube (1) of the package. The stepped edge (10) of each web (13,14) serves as the top-end edge (10,16) of the tube (1), the blank (I) of which is separated form the web (13,14) by (at 41) parting it in transverse relationship to their direction of movement (15), the blank being provided with a longitudinal sealing seam for formation of the tube. At the top end of the tube (1), there are formed extensions of oppositely disposed side walls (3,5) and projecting wall panels (8,9) which are folded over into the surface of the top (7), the top (7) being integrally moulded on the free edge (10) of the wall panel ( 8,9) and the adjacent stepped end edge (10).

A bottom end closure of a carton to be heat- and pressure-sealed has four substantially rectangular panels (P6, P7-P9, P12 and P14-P16) of which the panels (P7-P9 and P14-P16) are divided by score lines (S3, S7 and S13, S17) into inner, triangular sub-panels (P8 and P15) and outer triangular sub-panels (P7, P9 and P14, P16) and have central lugs formed by pairs of small, rectangular sub-panels (P10, P11 and P17, P18) providing for gas-tightness at the apices (A1 and A2) in the sealed closure. Score lines (S4, S6 and S14, S16) provide lines of weakness across the whole widths of the roots of the central lugs, so that the lugs, when each folded upon itself, can adjust to the orientation of an outwardly folded panel (P13) during tucking of the panel (P13) inwards of the lugs, which are sandwiched between the panels (6 and P13). In the blank, the lugs and the panels (P6 and P13) are so dimensioned that they can interdigitate with the corresponding lugs and panels of the bottoms of a row of identical blanks. Edge portions (E11 and E17) of protrusions of the panel (P12) commence adjacent to an parallel with the vertical edges of the panel (P12) and continue convexly curved towards the panel (P13), to co-operate with the folds between the panel (P6), on the one hand, and the sub-panels (P9 and P14), on the other hand, to enhance production and maintenance of self-alignment of the closure.

A one-piece box is disclosed which is foldable from a flat blank to an erect box. The box is provided with a corner interlock comprising a tab on the side wall extending through an opening in the front wall. A cover interlock is provided using a single panel front wall having a tab which extends through an opening in the cover. The box blanks may be cut from a single board in side-by-side nested relationship with a wall or flap of one box blank being of reduced height and receiving a protruding portion of the corresponding wall or flap of the adjacent box blank.

A novel plastic closure is disclosed having a self-engaging locking pilfer band arrangement for engagement with a locking ring on the neck of the container to which the closure is applied. The pilfer band includes a plurality of circumferentially spaced, inwardly extending relatively thin flexible wings or fingers which move to an out-of-the-way position during application of the closure to the container. When the closure is in place on the container, the wings are disposed such that they engage the surface of the locking ring on the container neck when the closure is moved for removal from the container. During removal, each wing engages the locking ring so that resistance to removal of the closure is created in the pilfer band, whereby areas of reduced strength fracture clearly indicating partial or complete removal of the closure from the container.