| 摘要 |
<p>PURPOSE:To make gas barrier characteristics excellent when retort treatment is not performed and to get rid of putrefaction, detrioration and discoloration of a content just after retort heating and sterilization treatment and after storage for a long time by providing steam diffusion-preventing layers with a specified steam permeability in such a way that they sandwiches a gas barrier layer so as to bringing them into contact with the gas barrier layer and providing an amorphous polyamide layer with a specified quantity of heat of fusion of crystallite and a specified glass transition temp. between the steam diffusion-preventing layer and an inner surface layer and an outer surface layer. CONSTITUTION:Steam diffusion-preventing layers 7 and 8 each with a steam permeabil ity measured at 40 deg.C of smaller than 60g/m<2>.24 hr are placed in such a way that they sandwiches a gas barrier layer 3 consistion of an ethylene-vinyl alcohol copolymer so as to bring them into contact with the gas barrier layer and substantially amorphous polyamide layers 4 and 5 each with a quantity of heat of fusion of crystallity measured by means of a differential scanning calorimeter of smaller than 2.0cal/g and a glass transition temp. measured by means of a calorimeter of 80-180 deg.C are provided between the steam diffusion-preventing layers and an inner surface layer 1 and an outer surface layer 2 wherein each a propylene polymer is a main ingredient.</p> |
