Patent ID: 8196373

Claim:
An improved pouch-making process comprising the steps of: (I) providing a monofilm or a multilayer film, said film comprising a flowable material packaging film comprising at least a resin blend of: (a) from about 33 wt % to about 80 wt % of at least one ethylene-C 4 to C 10 -α-olefin interpolymer having a melt-index of from 0.4 to 1.5 g/10 min (190° C., 2.15 kg), and a density of from 0.900 to 0.916 g/cm 3 ; and (b) from about 67 wt % to about 20 wt % of at least one propylene-based heterogeneous interpolymer of propylene with ethylene, or of at least one propylene-based heterogeneous interpolymer of propylene with ethylene and butene, said propylene-based heterogeneous interpolymer comprising: (i) from about 71 mol % to about 86 mol % propylene, and (ii) from about 29 mol % to about 14 mol % ethylene or ethylene and butene, wherein said propylene-based heterogeneous interpolymer has an overall weight average molecular weight (M w ) of at least about 400,000, a xylene soluble phase of not less than 30 wt %, with the xylene soluble phase having a M w of at least about 275,000, and wherein said propylene-based heterogeneous propylene-based interpolymer has a density of from 0.875 to 0.91 g/cm 3 ; wherein said film has a Hot Tack Initiation Temperature in the range of from about 100° C. to about 140° C. and a Hot Tack Strength of not more than about 5 N/inch in the temperature range of about 100° C. to about 150° C., when fabricated at a thickness of about 50 μm and tested using a JB Instrument Hot Tack Tester set at a 0.5 second dwell, 0.2 second delay time, 40 psi seal bar pressure, and 250mm/second peel rate; and wherein said film has a flex crack resistance such that it develops 5 or less pinholes per 300 cm 2 in 10,000 cycles of Gelbo Flex testing as measured according to ASTM F392; (II) forming said film into a tubular member; (III) heat-sealing longitudinal edges and then filling said pouch with flowable material; (IV) heat-sealing a first transverse end of said tubular member to form a pouch; and (V) sealing and cutting through a second transverse end of said tubular member to provide a filled pouch; said tubular member being filled continuously or intermittently; wherein said upper transverse seal is the bottom seal of the next pouch to be formed and filled.