To surely cut a film at a perforation part when an automatic packaging is performed by a method wherein a heat-shrinkable film having a resin layer comprising at least one of a polyethylene-based resin and a polypropylene- based resin, and having a specified rate of shrinkage, is used.
This heat-shrinkable film may satisfy 40≥A-B≥5 when it is taken that a temperature at which the increase amount of a rate of shrinkage in the vertical direction becomes a maximum is A°C, and a temperature at which the increase amount of a rate of shrinkage in the lateral direction becomes a maximum is B°C, and in order to make the film be cut by itself at a perforation part, a film of which the shrinkage stress in the vertical direction is 5 kgf/cm2 or higher is preferable. Then, as the composition, the film has a layer comprising at least one of a polyethylene-based resin and a polypropylene-based resin. Then, when the film greatly shrinks in the lateral direction, an engaging part 21 is formed between batteries at both ends and the film, and for this reason, when the film greatly shrinks in the vertical direction, the shrinkage in the vertical direction does not advance.
| WO/2006/004094 | OVERWRAP PACKAGE, PERFORATION FORMING METHOD, AND PERFORATION FORMING DEVICE |
| JPH0834100 | STRETCHED MULTILAYERED FILM |
| JPS58156652 | 【考案の名称】包装装置 |
HIGASA SHINICHI
HANEDA KENJI
OISHI MANABU
