FLEX CRACK RESISTANT LOW DENSITY POLYETHYLENE FILMS

摘要

A sealant film for use in a film structure for the manufacture of pouches and bags for containing flowable materials, the sealant film comprising 1) from about 2.0 to about 9.5 wt %, based on 100 wt % total composition, of an ethylene C₄-C₁₀ -alpha-olefin interpolymer having a density of from 0.850 to 0.890 g/cc and a melt index of 0.3 to 5 g/10min, the interpolymer being present in an amount that optimizes flex crack resistance as measured using a Gelbo Flex tester set up to test in accordance with ASTM F392, and minimizes reduction of thermal resistance, as measured using DSC (ASTM E794/E793) Differential Scanning Calorimetry (DSC) which determines temperature and heat flow associated with material transitions as a function of time and temperature, and stiffness of the sealant film layer as measured using Tensile Modulus of the polyethylene films measured in accordance with ASTM Method D882; 2) from about 70.5 wt % to about 98.0 wt %, based on 100 wt % total composition, of one or more polymers selected from ethylene homopolymers and ethylene C₄-C₁₀ -alpha-olefin interpolymers, having a density between 0.915 g/cc and 0.935 g/cc and a melt index of 0.2 to 2 g/10min; 3) from about 0 wt % to about 20.0 wt %, based on 100 wt% total composition, of processing additives selected from slip agents, antiblock agents, colourants and processing aids; and the sealant film has a thickness of from about 2 to about 60 µm.