Biaxially oriented high-density polyethylene films with improved sealant skin
Disclosed are compositions and methods for multilayer films, which, in one embodiment may comprise a core layer comprising at least 50 wt. % of high-density polyethylene. Further, the multilayer film may include a first skin layer comprising an ethylene-propylene polymer, and a second skin layer comprising at least one or more α-olefin copolymers and antiblock. One or more of the at least one or more α-olefin copolymers in the second skin layer, which may be a sealant skin layer, may include at least one ethylene-propylene-butylene polymer in combination with a plastomer and/or elastomer that contain propylene, ethylene, or a combination thereof.
1 . A multilayer film comprising:
a core layer consisting of: (i) at least 50 wt. % high-density polyethylene, (ii) linear low-density polyethylene; and (iii) hydrocarbon resin optionally in masterbatch solution, wherein (ii) and (iii) are present in a combined amount of 20 wt. % or less;
a first skin layer consisting of an ethylene-propylene polymer, antiblock in masterbatch solution, and optionally other additives; and
a second skin layer, which is a sealant skin, consisting of: (i) ethylene-propylene-butylene polymer, (ii) from about 15 wt. % through about 25 wt. % of one or more: α-olefin elastomers, α-olefin block copolymer elastomers, or ethylene α-olefin plastomers, and (iii) antiblock in masterbatch solution, and (iv) optionally other additives, wherein concentration of (i) is in majority in the second skin layer,
wherein the multilayer film is oriented in at least one direction,
wherein the multilayer film has an increase in minimum seal temperature as compared to the multilayer film having a second skin layer consisting of (i) and (iii).
2 . The multilayer film of claim 1 , further comprising one or more additives.
3 . The multilayer film of claim 1 , further comprising one or more tie layers.
4 . The multilayer film of claim 1 , wherein the hydrocarbon resin is in a polyethylene masterbatch.
5 . The multilayer film of claim 1 , wherein the one or more α-olefin elastomers, α-olefin block copolymer elastomers, or ethylene α-olefin plastomers are only propylene-ethylene polymers.
6 . The multilayer film of claim 1 , wherein at least one of the one or more α-olefin elastomers and/or block copolymers are propylene-based elastomers.
7 . The multilayer film of claim 1 , wherein the first skin layer is treated on a side opposing the core layer.
8 . The multilayer film of claim 1 , wherein the multilayer film is metallized.
9 . The multilayer film of claim 1 , wherein one outer layer of the multilayer film is coated.
10 . The multilayer film of claim 1 , wherein at least one outer layer of the multilayer film is laminated to a substrate.
11 . The multilayer film of claim 1 , wherein the first skin layer and/or the second skin layer have a thickness of about 1 μm or less.
12 . A method comprising providing the multilayer film of claim 1 and forming a package therefrom.
13 . The multilayer film of claim 1 , wherein a static coefficient of friction is at least 0.31.
14 . The multilayer film of claim 1 , wherein a kinetic coefficient of friction is at least 0.24.
15 . The multilayer film of claim 1 , wherein seal strength is at least 418 g/in at 240° F. with a jaw pressure of 60 psi, dwell time of 0.75 seconds, and cooling time of 20 seconds.
16 . The multilayer film of claim 1 , wherein the one or more α-olefin elastomers, α-olefin block copolymer elastomers, or ethylene α-olefin plastomers are only propylene-ethylene elastomers.
17 . The multilayer film of claim 1 , wherein the one or more α-olefin elastomers, α-olefin block copolymer elastomers, or ethylene α-olefin plastomers are only propylene-ethylene block copolymer elastomers.
18 . The multilayer film of claim 1 , wherein the one or more α-olefin elastomers, α-olefin block copolymer elastomers, or ethylene α-olefin plastomers are only propylene-ethylene plastomers.
19 . The multilayer film of claim 1 , wherein composition of the (ii) of the second skin layer consists of at least two members selected from a group consisting of: the α-olefin elastomers, the α-olefin block copolymer elastomers, and the ethylene α-olefin plastomers.