SINGLE POLYMER FILM STRUCTURES FOR USE IN STAND-UP-POUCHES

摘要

The present invention relates to film structure suitable for use in stand up pouches comprising all polyethylene material. The film structure can be a monolayer film or a multilayer film structure having specific requirements for each layer. The combination results in a film structure having adequate stiffness to function as a stand-up pouch while also providing acceptable water vapor transmission rates and good tear resistance. Such films have improved sustainability characteristics as they should permit down-gauging of the films and, can more easily be recycled, at least for the preferred embodiment comprising only polyethylene resins.

主权项

1. A laminated film structure suitable for use in stand up pouches comprising:
a) a first film comprising:
i) at least one surface layer (A) comprising from 70 to 100 percent by weight of the layer (A) of a linear low density polyethylene having a density from 0.89 to 0.91 g/cm3 and a melt index of less than 1.3 dg/min, and a peak melting point in the range of from 85° C. to 100° C., and a molecular weight distribution, Mw/Mn, in the range of from 2.0 to 3.0; andii) at least one additional layer (B) comprising from 70 to 100 percent by weight of the layer (B) of a first multimodal polyethylene polymer having a multimodal distribution in terms of molecular weight, wherein said first multimodal polyethylene comprises units derived from ethylene and at least one C3-C10 alpha-olefin, and wherein the first multimodal polyethylene polymer has a density in the range of from 0.950 to 0.965 g/cm3, a melt index in the range of from 0.8 to 1.2 dg/min, a peak melting point in the range of from 120° C. to 135° C. as measured by a differential scanning calorimeter, and a molecular weight distribution, Mw/Mn ratio greater than 5.0; b) at least a second film comprising:
i) a first surface layer (C) comprising from 60 to 100 percent by weight of the layer (C) of a second multimodal polyethylene polymer having a multimodal distribution in terms of molecular weight, wherein said second multimodal polyethylene comprises units derived from ethylene and at least one C3-C10 alpha-olefin, and wherein the second multimodal polyethylene polymer has a density in the range of from 0.910 to 0.930 g/cm3, a melt index in the range of from 0.8 to 1.2 dg/min, a peak melting point in the range of from 110° C. to 130° C., and a molecular weight distribution, Mw/Mn ratio in the range of from 3.0 to 4.0;ii) at least one core layer (D) comprising from 70 to 100 percent by weight of the layer (D) of a third multimodal polyethylene polymer having a multimodal distribution in terms of molecular weight, wherein said first multimodal polyethylene comprises units derived from ethylene and at least one C3-C10 alpha-olefin, and wherein the first multimodal polyethylene polymer has a density in the range of from 0.950 to 0.965 g/cm3, a melt index in the range of from 0.8 to 1.2 dg/min, a peak melting point in the range of from 120° C. to 135° C. as measured by a differential scanning calorimeter, and a molecular weight distribution, Mw/Mn ratio greater than 5.0; andiii) a second surface layer (E) comprising from 60 to 100 percent by weight of the layer (E) of a copolymer comprising units derived from ethylene and at least one alpha-olefin in the range of C3-C10 wherein said copolymer has a density from 0.91 to 0.93 g/cm3, a melt index in the range of from 0.8 to 1.2 dg/min, a peak melting point in the range of from 110° C. to 130° C. and a molecular weight distribution, Mw/Mn ratio in the range of from 3.0 to 4.5; wherein the first film is laminated to the second film such that the additional layer (B) of the first film is adjacent to the first surface layer (C) of the second film; and wherein the laminated film structure is characterized by the substantial absence of polymers other than polyethylene homopolymers and copolymers.