LAMINATE FOR RETORT PACKAGING

To provide a laminate for retort packaging, which has an environmentally friendly heat-resistant base material layer with a reduced weight design of two layers, has excellent low-temperature impact resistance, heat sealability, low-temperature puncture resistance and flex whitening resistance, and further, when a packaging bag filled with retort food is heated in a microwave oven or the like, allows the heat seal strength to be appropriately reduced and steam to pass through, thereby preventing the packaging bag from bursting and contents from scattering or leaking.SOLUTION: There is provided a laminate formed by laminating a polypropylene film on one side of two or less heat-resistant base layers, in which the weight loss rate is 10% or more compared to a laminate with a base mass of 66 to 104 g per 1 m2 which consists of a non-oriented polypropylene film of 40 to 70 μm on one side of a heat-resistant base layer consisting of a vapor-deposited biaxially oriented polyethylene terephthalate film of 9 to 12 μm and a biaxially oriented polyamide film of 10 to 15 μm; and the bag retention rate is 40% or higher when a 150 mm long×130 mm wide three-way bag made by heat-sealing three sides at 210°C is filled with 160 g of water, sealed at 210°C using an impulse sealer, and then dropped five times with a load of 1 kg from a height of 20 cm using a DuPont drop impact tester in 5°C atmosphere.SELECTED DRAWING: None 【課題】レトルト包装用積層体として、環境を配慮した耐熱性基材層が２層の減量化設計において、耐低温衝撃性、ヒートシール性、耐低温突き刺し性、耐屈曲白化性に優れ、さらにレトルト食品を充填した包装袋を電子レンジ等で加熱する際にヒートシール強度が適度に低下して通蒸し、包装袋が破裂して内容物が飛散あるいは洩出することを防止できるレトルト包装用積層体を提供する。【解決手段】 ２層以下の耐熱性基材層の片面にポリプロピレン系フィルムが積層された積層体であって、蒸着二軸延伸ポリエチレンテレフタレートフィルム９～１２μｍと二軸延伸ポリアミドフィルム１０～１５μｍを積層した耐熱性基材層の片面に無延伸ポリプロピレン系フィルム４０～７０μｍが積層された積層体１ｍ２辺りの質量６６～１０４ｇを基準としたときに対して減量率が１０％以上であり、２１０℃で３方をヒートシールした縦１５０ｍｍ×横１３０ｍｍの三方袋に、水１６０ｇを充填した後にインパルスシーラにて２１０℃設定で密封シールし、デュポン式落下衝撃試験機を用いて５℃雰囲気下で高さ２０ｃｍから荷重１ｋｇを５回落錘したときの破袋保持率が４０％以上である積層体。【選択図】なし