High seal strength-high barrier metallized biaxially oriented polypropylene film for hermetic packaging

Abstract

Abstract The present invention relates to a high seal strength metallized biaxially oriented polypropylene (mBOPP) having superior barrier properties toward water vapor and oxygen gas. The film product comprises of six layers, i.e. core layer C, layer T1 located on a first side layer C, layer B located on a top of layer T1, layer M located on a top of layer B, layer T2 located on second side of layer C, and layer A located on a bottom side of layer T2. Layer C comprises of a polypropylene homopolymer and a polypropylene elastomer; layer T1 comprises of a maleic anhydrate grafted polypropylene; layer B comprises of ethylene vinyl alcohol; layer M comprises of aluminium which is produced using vaccum metallizing process; layer T2 comprises of polypropylene copolymer, and layer A comprises of polypropylene copolymer and antiblock additives to obtain COF below 0.8 and SIT below 120°C. A mBOPP film has a sealing strength above 1200 gram / 25mm, an elastic modulus below 1300 N / mm2, a WVTR below 0.3 gram / m2.day and a O2TR below 0.3 cc / m2.day. Total film thickness is 15 to 50μm and density 0.55 to 0.95 gram / cm3. Abstract The present invention relates to a high seal strength metallized biaxially oriented polypropylene (mBOPP) having superior barrier properties toward water vapor and oxygen gas. The film product comprises of six layers, i.e. core layer C, layer T1 located on a first side layer C, layer B located on a top of layer T1, layer M located on a top of layer B, layer T2 located on second side of layer C, and layer A located on a bottom side of layer T2. Layer C comprises of a polypropylene homopolymer and a polypropylene elastomer; layer T1 comprises of a maleic anhydrate grafted polypropylene; layer B comprises of ethylene vinyl alcohol; layer M comprises of aluminium which is produced using vaccum metallizing process; layer T2 comprises of polypropylene copolymer, and layer A comprises of polypropylene copolymer and antiblock additives to obtain COF below 0.8 and SIT below 120°C. A mBOPP film has a sealing strength above 1200 gram / 25mm, an elastic modulus below 1300 N / mm², a WVTR below 0.3 gram / m2.day and a OTR below 0.3 cc / m ²².day. Total film thickness is 15 to 50um and density 0.55 to 0.95 gram / cm³. 20 25 20 31 83 05 M ay 2 02 5 2 0 2 5 2 0 3 1 8 3 0 5 M a y 2 0 2 5 1 / 1 Figure 1 5 Schematic diagram of film structure M Aluminium B Metal receptive layer T1 Intermediate layer T1 C Core Layer T2 Intermediate layer T2 A Skin layer A 1 / 1 M Aluminium Metal receptive B layer Intermediate T1 layer T1 C Core Layer Intermediate T2 layer T2 A Skin layer A 5 Figure 1 Schematic diagram of film structure 20 25 20 31 83 05 M ay 2 02 5 M A l u m i n i u m 2 0 2 5 2 0 3 1 8 3 0 5 M a y 2 0 2 5 T 1 I n t e r m e d i a t e 5