| 摘要 |
A thermoformed container having a granular product therein being made from two webs of films of flexible material is provided. According to one embodiment of the present invention, a web of flexible film material is thermoformed into a series of cup-shaped containers, each cup having a peripheral flange around its mouth. The cups are then partially filled with a granular product such that there is a headspace between the product's top surface and the cup's peripheral flange. The cups are then placed in a vacuum/sealing/shaping chamber wherein substantially all the air inside the cups is removed, followed by sealing an upper web of flexible film material to each cups's peripheral flange. Before the sealed containers are removed from the vacuum/sealing/shaping chamber, a shaping die located in the bottom of the chamber is thrust upwardly into each cup's bottom wall. The shaping die forces the granular product up into the headspace and pushes the cup's excess film material upwardly, thereby forming a concave impression or dome in the cup's bottom wall and subsequently reducing the amount of film wrinkling exhibited by the containers. The chamber is then returned to atmospheric pressure before the containers are removed. Atmospheric pressure holds the containers in this pre-selected solid shape, which is not only easy to handle in subsequent operations, but much more aesthetically pleasing than if the containers were not given a preselected shape. In addition, the reduced wrinkling of the lower cup's film material significantly increases the container's scuff and abrasion resistance. |
