Cardboard with edges sealed by a mixture of hot-melt adhesive and wax includes two surface sheets and an intermediate core material. The surface sheets have a pair of corresponding edges that form an edge opening therebetween communicating with the interstitial spaces in the cardboard and sealed by an edge-sealing structure in the interstitial spaces. The edge-sealing structure includes a primer layer formed by an adhesive mixture and a sealing layer formed by a sealing mixture. The adhesive mixture is made by mixing the hot-melt adhesive with the wax, adhesively bonds the surface sheets and the intermediate core material together, and forms the primer layer with voids and providing a porous supporting surface to be coated with the sealing mixture. The sealing mixture is less adhesive than the adhesive mixture and fills up the voids in the primer layer. Thus, the cardboard achieves waterproofness and thermal and acoustic insulation at low cost.

The present invention concerns a method of splicing two sealing strips and a sealing strip formed by the method. The sealing strip is placed at longitudinal edges of a packaging material web, used for packaging containers for liquid foods. The sealing strips to be spliced are cut each forming an oblique edge of about 45, as seen in plan view. The oblique edges are then placed one on top of the other forming an overlapping area. The overlapping area is in the form of an oblique band having a length of about 3 mm. The ends of the sealing strips are then fused together by heating both from one side at the overlapping area.

A container of paper or paper-like material, having a sleeve and having a bottom and/or a cover, wherein the bottom and/or cover and the sleeve are connected in substantially liquid-tight fashion in the region of a bottom skirt and/or cover skirt. The sleeve is composed of a sheetlike blank, and wherein regions adjoining a first side edge and adjoining a second side edge, situated opposite the first side edge, of the blank are laid one on top of the other so as to form an overlapping side seam and connected to one another by material-bonding engagement, wherein at least the region adjoining the first side edge forms a step which is offset relative to the rest of the blank.