| 摘要 |
PROBLEM TO BE SOLVED: To reduce occurrence of damage such as cracks or pin holes on a metallic foil in a retort packaging material comprising the metallic foil as an intermediate layer and buffer layers laminated on both sides of it even after rocking retort sterilization by laminating at least two or more layers outside one of the buffer layers. SOLUTION: On a resin layer 1 printed in gravure ink, a dry lamination adhesive comprising a thermosetting resin is applied as an adhesive layer 2 and dried. While a surface of the adhesive layer 2 is sticky, a resin layer 3 is stuck thereon with heat and pressure applied. Then on a side of the resin layer 3, a similar adhesive is applied and dried, and then a resin layer 5 is stuck with heat and pressure applied via that adhesive layer 4. Then on a side of the resin layer 5, a similar adhesive is applied and dried, and then an alloy Al foil is stuck with heat and pressure applied as a metallic foil layer 7 via that adhesive layer 6. Thereafter, the metallic foil layer 7 and a resin layer 9 which is of the same material as the resin layer 5, which may be located innermost when a bag is made, are dry-laminated using a similar adhesive as an adhesive layer 8. |
