Heat Sealable Polyethylene Film And Method For Its Preparation
Patent #: 7,018,710
Inventor(s): Kalle Kallio, Jari Äärilä, Merete Skar and Arja Lehtinen
Company: Borealis Technology Oy
A process for the preparation of a heat sealable film comprising a core layer and a sealing layer has been patented. The process includes attaching the core layer to the sealing layer. The sealing layer comprises an ethylene copolymer composition on which there are two distinct maxima in the TREF fractogram of the ethylene copolymer composition. At least 10% of the ethylene copolymer composition elutes in TREF at a temperature of less than 50°C. At least 25% of the ethylene copolymer composition elutes in TREF at a temperature of higher than 75°C. None of the ethylene copolymer composition elutes in TREF at a temperature of higher than 100°C. The ethylene copolymer composition comprises two components, one of which is of relatively high comonomer content and high molecular weight, the other of which is of relatively low comonomer content and low molecular weight. Both components are prepared by polymerization of ethylene with a C3-20 alpha-olefin in the presence of a single site catalyst. The ethylene copolymer composition has a density of between 905 and 930 kg/m3, and an MFR2 between 0.3 and 4.0 g/10 min.
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