| 摘要 |
Rectangular sealed package (IA) is made from a folded strip of a laminate having inner and outer plastics layers. The adjacent ends (20) of the folded strip are heat sealed together. A fold (5a) is provided with external surface roughening (10a) which assists subsequent opening of the package. The package may have a single fold, two folds (5a,5b) and an outwardly extending central sealed section (20) or a plurality of folds to form a pleated package. Pref. all folds are surface roughened and the roughening may be straight, meandering or helical e.g. on a sausage packing. The roughening may be made by e.g. sandpaper. Alternatively, a laser, ultrasonics or corona or plasma discharge can be used to provide a plurality of perforations or linear recesses. The surface irregularities formed by roughening may be filled with the same material as that of the inner layer. The outer layer may be a mono-axially stretched polypropylene, polyether or polyester film. The inner layer may be polyethylene. A pref. laminate has the inner layer made of polyethylene bonded to aluminium foil bonded to polyethylene. |
