| 主权项 |
1. A multilayer film comprising four or more discrete layers comprising:
a. a first and a second external layer, wherein each external layer independently comprises:
i. from 60 to 100% by weight of the external layer of a linear low density polyethylene resin characterized by having a melt index in the range of 0.3 to 4 g/10 min and a density in the range of from 0.917 to 0.950 g/cm3, and a MWD of from 3 to 9 andii. from 0 to 40% by weight of the external layer of a first high pressure low density polyethylene resin characterized by having a melt index in the range of 0.3 to 4 g/10 min and a density in the range of from 0.918 to 0.935 g/cm3; b. at least one internal stiffening layer, wherein the stiffening layer or layers cumulatively comprise at least 20% of the film by weight and wherein each stiffening layer independently comprises:
i. from 60 to 100% by weight of the stiffening layer of a stiffening resin selected from the group consisting of 1) a polypropylene resin, wherein said polypropylene resin is selected from the group consisting of homopolymer polypropylene and a propylene random copolymer derived from more than 90% by weight propylene and up to 10% by weight ethylene or one or more alpha olefins having 4 to 10 carbon atoms, wherein the polypropylene resin is characterized by having a melt flow rate in the range of 0.1 to 2 g/10 min; and 2) a first linear high density polyethylene resin characterized by having a melt index in the range of 0.25 to 4 g/10 min and a density in the range of from 0.935 to 0.975 g/cm3; and 3) blends thereof, and; c. at least one internal shrink layer, wherein each shrink layer independently comprises:
i. from 50 to 100% by weight of the shrink layer of a second high pressure low density polyethylene resin characterized by having a melt index in the range of 0.2 to 1 g/10 min and a density in the range of from 0.917 to 0.935 g/cm3;andii. from 0 to 50% of a second linear high density polyethylene resin characterized by having a melt index in the range of 0.2 to 4 g/10 min and a density in the range of from 0.930 to 0.975 g/cm3; wherein the multilayer film is characterized by having a gloss of at least 60% at 45 degrees, together with a 2% secant tensile modulus greater than 400 MPa in the machine direction, the cross direction or both the machine direction and the cross direction. |
