| 摘要 |
<p>A packaging material for food to be subjected to high-temperature short-time sterilization, which comprises a flexible laminate sheet including (a) a heat-sealable inner face layer of a crystalline polypropylene, (b) an outer face layer of a thermoplastic or thermosetting resin having a melting point or decomposition point higher than the melting point of said polypropylene and, if desired, (c) an oxygen-barrier layer interposed between said layers (a) and (b), said polypropylene layer being composed of a film of a polypropylene having a melt flow index of 0.5 to 3, said film being characterized in that (i) when the film is extracted in salad oil at 130 DEG C. for 30 minutes, the amount extracted of the polypropylene is smaller than 1500 ppm, (ii) the polypropylene film has a pseudohexagonal crystal form or a crystal form of a combination of the pseudohexagonal system and alpha -monoclinic system and a degree of orientation not higher than 3.0 and (iii) the surface of the polypropylene film confronting the layer (b) has a tension in the wet state (wetting tension T1) of at least 38 dyne/cm when it is allowed to stand still in an atmosphere of a temperature of 20 DEG C. and a relative humidity of 40% for 1 week.</p> |
