Container with heat seal surface having a substantially planar portion

A sealed composite container for products comprising:

• a tubular body member comprising at least one paperboard body ply and having an inner surface;
• a liner ply adhered to the inner surface of said tubular body member and comprising a barrier layer, at least one end of said body member and said liner ply being rolled outwardly to form a rim, said rim defining a heat seal surface having a substantially planar portion, an inner portion sloping away from said substantially planar portion and toward the interior of the container, and an outer portion sloping away from said substantially planar portion and toward the exterior of the container, the inner portion sloping away from the substantially planar portion at a greater rate than the outer portion;
• and
• a lid operatively positioned adjacent to said rim and heat sealed thereto, said lid comprising a barrier layer;
• wherein at least one of said lid and said liner ply further comprises a seal layer comprising a heat sealable composition, said seal layer forming a heat seal between said lid and said liner ply comprising an inner bead formed of the heat sealable composition and facing the interior of the container and an outer bead formed of the heat sealable composition on the opposite side of the heat seal from the inner bead, said heat seal further defining a substantially planar portion between said inner and outer beads.

A method of manufacturing a sealed container for products comprising:

• providing a tubular member comprising at least one paperboard body ply having an inner surface and a liner ply adhered to the inner surface of the body ply, the liner ply comprising a barrier layer;
• rolling outwardly at least one end of the tubular member to form a rim;
• shaping the rim such that the rim defines a heat seal surface having a substantially planar portion;
• providing a lid for closing the end of said tubular member, the lid comprising a barrier layer, at least one of said lid and said liner ply further comprising at least one seal layer comprising a heat sealable composition, the seal layer being operatively positioned to form a heat seal between the lid and the liner ply;
• contacting the rim and the lid;
• heating the seal layer under conditions sufficient to render the heat sealable composition of the seal layer flowable;
• and
• pressing the rim and the lid together to form a hermetic heat seal therebetween having a substantially planar portion.