BIAXIALLY ORIENTED POLYPROPYLENE FILM AND PACKAGE

• Main Authors: KAWAMURA SHIGEO, TAJIMA TOMOKI, KURIMOTO MASAFUMI, KURAMOTO NAOHIKO, OGAWA YUICHIRO
• Format: Patent
• Language: English; Japanese
• Published: 28.10.2021
• Subjects: ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS,e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES,DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; CONVEYING; HANDLING THIN OR FILAMENTARY MATERIAL; LAYERED PRODUCTS; LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT ORNON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM; PACKAGES; PACKAGING ELEMENTS; PACKING; PERFORMING OPERATIONS; STORING; TRANSPORTING

To provide an OPP film which has high fusion cutting seal strength and fracture energy of a fusion cutting seal part, and is excellent in heat seal strength and low temperature heat sealability.SOLUTION: A biaxially oriented polypropylene film has a base material layer, and a skin layer provided on one surface or both surfaces of the base material layer. The skin layer contains 60 mass% or more and 80 mass% or less of a polypropylene resin (A) and 20 mass% or more and 40 mass% or less of a propylene-ethylene copolymer, and has a thickness of more than 1 μm and less than 2 μm. The polypropylene resin (A) has a melt flow rate at 230°C of 3 g/10 min or more and 20 g/10 min or less and a melting point of 120°C or higher and lower than 135°C, the propylene-ethylene copolymer has a melt flow rate at 230°C of 1 g/10 min or more and less than 3 g/10 min and a melting point of 135°C or higher and 150°C or lower, the base material layer contains 77 mass% or more and 99 mass% or less of the polypropylene resin (B) and 1 mass% or more and 23 mass% or less of a polyethylene resin, and the polyethylene resin has a melt flow rate at 190°C of 1.5 g/10 min or more and 15 g/10 min or less and a density of 0.910 g/cm3-0.935 g/cm3.SELECTED DRAWING: None 【課題】溶断シール強度及び溶断シール部分の破断エネルギーが高く、かつヒートシール強度及び低温ヒートシール性にも優れるＯＰＰフィルムを提供することを課題とする。【解決手段】基材層と、該基材層の片面又は両面に設けられたスキン層とを備える、二軸延伸ポリプロピレン系フィルムであって、前記スキン層は、ポリプロピレン系樹脂（Ａ）を６０質量％以上８０質量％以下、プロピレン−エチレン共重合体を２０質量％以上４０質量％以下含み、かつ厚みが１μｍ超２μｍ未満であり、前記ポリプロピレン系樹脂（Ａ）は、メルトフローレートが２３０℃において３ｇ／１０分以上２０ｇ／１０分以下、融点が１２０℃以上１３５℃未満であり、前記プロピレン−エチレン共重合体は、メルトフローレートが２３０℃において１ｇ／１０分以上３ｇ／１０分未満、融点が１３５℃以上１５０℃以下であり、前記基材層は、ポリプロピレン系樹脂（Ｂ）を７７質量％以上９９質量％以下、ポリエチレン樹脂を１質量％以上２３質量％以下含み、前記ポリエチレン樹脂は、メルトフローレートが１９０℃において１．５ｇ／１０分以上１５ｇ／１０分以下で、密度が０．９１０ｇ／ｃｍ３〜０．９３５ｇ／ｃｍ３である、二軸延伸ポリプロピレン系フィルム。【選択図】なし