Packing container and blank for use in the manufacture thereof

A sheet material blank for constructing a sealed gabletop container, said blank comprising:

• first, second, third and fourth side wall panels;
• bottom closure panels for forming a bottom of said container;
• and first, second, third and fourth top panels connected respectively to the first, second, third and fourth side wall panels, said top panels each including a sealing zone spaced from said side wall panels, said second and fourth top panels including a substantially triangular fold-in panel and a pair of substantially triangular back folding panels, with the apex of each fold-in panel being located approximately midway of the length of the sealing zone of the respective top panel, said sealing zones each having a heat sealable layer of thermoplastic material extending thereacross, said sealing zone at said second panel having a seal preventing coating located thereon, and a heat sealable film superimposed on said seal preventing coating and overlapping the edges of said seal preventing coating, whereby when said container is formed from said blank with the sealing zones heat sealed, said seal preventing coating is easily separated from said thermoplastic layer upon opening.