Patent Description:
Cigarettes conventionally have been sold in packages, with each package often containing twenty (<NUM>) cigarettes. Typical cigarette packages have a generally rectangular parallelepiped form. One type of popular cigarette package employs a container having the form of a so-called "hard pack," "crush proof box" or "hinged lid package. " See, for example, <CIT>; <CIT>; <CIT>; <CIT>; and <CIT> Another type of popular cigarette package employs a container having the form of the so-called "soft pack. " See, for example, <CIT>; <CIT>; and <CIT>. Both types of cigarette packages are normally packed in cartons also of generally rectangular parallelepiped form, typically ten (<NUM>) packages to a carton.

Additional examples of cigarette packages can be found in <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; and <CIT>.

The above-identified cigarette packages are typically formed from folded and glued paper material. The paper material provides the structural rigidity for the cigarette packages. However, paper board in it of itself does not provide the necessary moisture retention properties for proper storage of tobacco products. Accordingly, most commercial cigarette packages are enclosed within a plastic film that prevents moisture loss from within the pack to the outside. The plastic films are typically a petroleum derived transparent biaxially oriented and heat sealable polypropylene film that has an inherent moisture barrier. The moisture transmission rate through these polypropylene films is about <NUM>/m<NUM>/day when measured at <NUM>° C and <NUM>% relative humidity by ASTM D1249. This moisture barrier keeps the tobacco within the pack moist for a several months while such that the packages can have a multi-month shelf life. However these films are not considered sustainable because of the petroleum based origin. Further, the petroleum derived plastic films are not biodegradable to any extent and contribute to landfill waste.

<CIT> discloses examples of sustainable films having excellent moisture transmission rates suitable for tobacco packaging.

<CIT> discloses a polylactic acid biaxial stretched laminate film for packaging comprising polymeric layers containing a preset amount of aliphatic polyester copolymer and polylactic acid.

Accordingly, it would be desirable to provide an alternative sustainably sourced transparent film that is biodegradable and that provides necessary moisture barrier characteristics.

The above and other needs are met by aspects of the present disclosure which, in a first aspect, provides a moisture barrier coated film according to claim <NUM>. The film includes a first layer comprising a first material having a first melting point. The film further includes a second layer comprising a second material having a second melting point. The second melting point is lower than the first melting point. The first side of the second layer bonded to a first side of the first layer. The film includes a moisture barrier coating applied to a second side of the second layer, the moisture barrier coating comprising a metal-oxide.

In second aspect, a method of making a film having a moisture barrier coating according to claim <NUM> is provided. The method includes forming a first layer comprising a first material having a first melting point. The method further includes forming a second layer comprising a second material having a second melting point. The second melting point is lower than the first melting point. The first side of the second layer bonded to a first side of the first layer. The method further
includes coating a second side of the second layer with a moisture barrier coating comprising a metal-oxide. The second side of the second layer opposite the first side of the second layer.

In a third aspect, a package according to claim <NUM> is provided. The package includes a main body and a top formed of a paper material. The package includes a central compartment formed by the top and the main body. The package further includes a wrapping formed of a film. The film includes a first layer comprising a first material having a first melting point and a second layer comprising a second material having a second melting point. The second melting point is lower than the first melting point. A first side of the second layer bonded to a first side of the first layer. The film further includes a moisture barrier coating applied to a second side of the second layer, the moisture barrier coating comprising a metal-oxide.

Further features and advantages of the present disclosure are set forth in more detail in the following description.

The present disclosure now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all aspects of the disclosure are shown. As used in this specification and the claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

Various embodiments described herein relate to a moisture barrier film for packaging, such as tobacco or cigarette packaging. The film comprises polylactic acid ("PLA") that is both biodegradable and transparent. In some arrangements, the film is corn-derived. The film includes multiple layers of PLA, with a base layer having a relatively high melting point compared to two outer layers, which have a relatively low melting point. The outer layers provide heat sealing capabilities to the film. The film is coated with a metal oxide layer comprised of aluminum oxide, titanium oxide, and/or aluminum-titanium oxide having a coating thickness of <NUM>-<NUM> using an atomic layer deposition ("ALD") coating method. The ALD coating to the PLA film results in a moisture transmission rate of less than <NUM>/m<NUM>/day after the film has been subjected to creasing, which induces cracking of the ALD metal oxide layer. Accordingly, the described film is suitable for use as a substitute for polypropylene film for overwrapping cigarette packs. The appearance of the PLA wrapped pack is similar to, or even better than, packs wrapped with the polypropylene film.

Referring to <FIG>, a cross-sectional view of an example film <NUM> is shown. The film <NUM> is a multi-layer film comprised of a base layer <NUM>, an outer layer <NUM>, and an inner layer <NUM>. The base layer <NUM> is positioned between the outer layer <NUM> and the inner layer <NUM>. The base layer <NUM>, the outer layer <NUM>, and the inner layer <NUM> have a combined thickness of between <NUM> and <NUM> microns thick. In some arrangements, the combined thickness of the base layer <NUM>, the outer layer <NUM>, and the inner layer <NUM> is <NUM> microns thick. In some arrangements, the thicknesses of the outer layer <NUM> and the inner layer <NUM> are each between <NUM> and <NUM> microns thick. In some arrangements, the base layer <NUM>, the outer layer <NUM>, and the inner layer <NUM> are formed and bonded together though a co-extrusion process. The film <NUM> may be rolled around a core after the extrusion process.

The outer layer <NUM> and the inner layer <NUM> are comprised of a first material. The first material is a first polylactic acid ("PLA") material. The first PLA material is transparent and biodegradable. In some arrangements, the first PLA material is corn-based. The first PLA material has a first melting temperature. In some arrangements, the first melting temperature is less than <NUM> degrees Celsius. In further arrangements, the first melting temperature is less than <NUM> degrees Celsius. The base layer <NUM> is comprised of a second material that is transparent and that has a second melting temperature. The second melting temperature is higher than the first melting temperature, which provides the film <NUM> with heat sealing capabilities. In some arrangements, the second material is a second polylactic acid material. The second PLA material may be corn-based. In other arrangements, the second material is a bio-based polypropylene. In further arrangements, the second material is the first PLA material that has been modified to have a higher melting temperature than the first melting temperature. In some arrangements, the second melting temperature is between <NUM> and <NUM> degrees Celsius.

The film <NUM> includes a coating <NUM>. The coating <NUM> provides a moisture barrier to the film <NUM>. The coating <NUM> is applied to the free surface of the outer layer <NUM> such that the outer layer <NUM> is positioned between the coating <NUM> and the base layer <NUM>. The coating <NUM> is also applied to the free surface of the inner layer <NUM> such that the inner layer <NUM> is positioned between the coating <NUM> and the base layer <NUM>.

The coating <NUM> is a transparent or substantially transparent metal oxide coating. In some arrangements, the coating <NUM> is an aluminum-titanium oxide ("ATO"). In other arrangements, the coating <NUM> is an aluminum oxide or a titanium oxide. Coatings made from the ATO are more flexible and more crack-resistant than coatings made from aluminum oxide or titanium oxide. In other arrangements, the coating comprises other metal oxides, such as silicon dioxide (SiO<NUM>), zinc oxide (ZnO), or the like. The coating <NUM> is applied to the film through an
atomic layer deposition ("ALD") process. In some arrangements, the ALD process occurs under vacuum. In other arrangements, the ALD process occurs at atmospheric pressure. In some arrangements, the ALD chamber has a temperature of less than <NUM> degrees Celsius. The ALD process may be a thermal ALD process or a plasma enhanced ALD ("PEALD") process. During the ALD process, the roll of film <NUM> without the coating <NUM> is fed through an ALD coating machine, in which the film <NUM> is subjected to exposures of metal precursor(s) and oxidizers to deposit the desired ALD coating on the film <NUM>. In some arrangements, the ALD coating is only applied on one side of the film <NUM>. In other arrangements, the ALD coating is applied on both sides of the film <NUM> either during a single pass or through multiple passes of the film <NUM> through the ALD coating machine. Accordingly, the metal oxide is deposited on the film <NUM> (e.g., on the outer layer <NUM> and/or on the inner layer <NUM>) to form the coating <NUM>. In some arrangements, the coating <NUM> is formed to a thickness of <NUM> nanometers.

As described above, the coating <NUM> provides a moisture barrier to the film <NUM>. After the film is coated with the coating <NUM>, the film <NUM> has a moisture transmission rate of less than <NUM>/m<NUM>/day after the film <NUM> has been subjected to creasing (e.g., as would be done when using the film to wrap a package). The creasing induces cracking of the coating <NUM>. In some arrangements, the film <NUM> has a moisture transmission rate of less than <NUM>/m<NUM>/day after the film <NUM> has been subjected to creasing.

As described in further detail below, the film <NUM> can be used as a wrapping around packaging products to seal the contents within the packaging from the ambient. The resulting packaging products wrapped in the film have both moisture barrier characteristics and heat sealability characteristics.

In various embodiments, the invention described herein relates to a method of making the film <NUM>. Referring to <FIG>, a flow diagram of a method <NUM> of making the moisture barrier film <NUM> is shown according to an example embodiment.

The method <NUM> begins when the base layer <NUM> of the film is formed. In some arrangements, the base layer <NUM> is formed by extruding the second material to form a film of the base layer <NUM>. The base layer <NUM> is formed to have a thickness between <NUM> and <NUM> microns. In some arrangements, the base layer <NUM> is formed to have a thickness of <NUM> to <NUM> microns. As described above, in some arrangements the second material is a PLA material. The PLA material may be corn-based. In other arrangements, the second material is a bio-based polypropylene.

The outer layer <NUM> is formed at <NUM>. In some arrangements, the outer layer <NUM> is formed by extruding the first material over one side of the base layer <NUM>. The outer layer <NUM> is formed to have a thickness between <NUM> and <NUM> microns. As described above, the first material is a PLA material, such as a corn-based PLA material.

The inner layer is formed at <NUM>. In some arrangements, the inner layer <NUM> is formed by extruding the first material over the side of the base layer <NUM> opposite the outer layer <NUM>. The inner layer <NUM> is formed to have a thickness between <NUM> and <NUM> microns. As described above, the first material is a PLA material, such as a corn-based PLA material.

In some arrangements, the base layer <NUM>, the outer layer <NUM>, and the inner layer <NUM> are formed in a single manufacturing process, such as a co-extrusion manufacturing process.

The partially completed film comprising the base layer <NUM>, the outer layer <NUM>, and the inner layer <NUM> is wrapped around a core to form a roll of partially completed film at <NUM>. In some arrangements, the partially completed film is wound around the core as the partially completed film exits the extrusion machine or machines. Wrapping the partially completed film around the core to form a roll of the partially completed film allows for easy storage and transportation of the partially completed film.

The coating <NUM> is applied at <NUM>. The partially completed film is fed from the roll into an ALD coating machine. As the partially completed film is fed through the ALD coating machine, the coating <NUM> is deposited on the outer surface of the outer layer <NUM>. The ALD coating machine may utilize a PEALD process. In some arrangements, the ALD chamber of the ALD coating machine has a temperature of less than <NUM> degrees Celsius during the ALD coating process. The thickness of the coating <NUM> is between <NUM> and <NUM> nanometers thick. In further arrangements, the thickness of the coating <NUM> is <NUM> nanometers thick. In some arrangements, the coating <NUM> is an ATO. In other arrangements, the coating <NUM> is an aluminum oxide or a titanium oxide. In further arrangements, the coating <NUM> comprises other metal oxides, such as silicon dioxide (SiO<NUM>), zinc oxide (ZnO), or the like. The ALD coating machine also applies the coating <NUM> to the outer surface of the inner layer <NUM>. The coating <NUM> can be applied to both sides in a single pass of the film <NUM> through the ALD coating machine, or through multiple passes of the film <NUM> through the ALD coating machine. The total thickness of the completed film <NUM> is between <NUM> and <NUM> microns thick. In some arrangements, the total thickness of the film is <NUM> microns thick.

The completed film <NUM> is wrapped around a core to form a roll of completed film <NUM> at <NUM>. After exiting the ALD coating machine, the film <NUM> is wrapped around a core to form a roll of the completed film <NUM>. The roll of completed film <NUM> can be stored for later processing or use. Wrapping the completed film <NUM> around the core to form a roll of the completed film <NUM> allows for easy storage and transportation of the completed film <NUM>.

In various embodiments, the invention described herein relates to a package that is wrapped in the moisture barrier film <NUM>. For example, the package may be a cigarette pack, such as those described in <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; and <CIT>.

<FIG> shows a perspective view of a cigarette pack <NUM>. The cigarette pack <NUM> includes a top lid <NUM> and a main body <NUM>. The top lid <NUM> and the main body <NUM> are comprised of a paper material, which is at least partially permeable to moisture. As shown in <FIG>, the top lid <NUM> can be rotated away from the main body <NUM> along a hinge <NUM> formed from a crease in the paper material. When the top lid <NUM> is rotated away from the main body <NUM>, a central compartment <NUM> is revealed. The central compartment <NUM> is sized and shaped to store cigarettes in any of the manners described in the above mentioned patent documents. When the top lid <NUM> is closed (e.g., as shown in <FIG>), the central compartment <NUM> is partially sealed from the ambient environment. However, moisture can still pass through the paper material (e.g., into the central compartment <NUM> or out of the central compartment <NUM>).

Accordingly, after the contents (e.g., cigarettes) are loaded into the central compartment <NUM>, the top lid <NUM> is closed and the pack <NUM> is wrapped in the film <NUM>. As shown in <FIG>, the pack <NUM> is wrapped in the film <NUM>. The film <NUM> is folded and creased to form overlapping flaps <NUM> and <NUM>. The flaps <NUM> and <NUM> are sealed with heat. When exposed to the heat, the outer layer <NUM> and the inner layer <NUM> become pliable and partially melt to stick the flaps <NUM> and <NUM> to each other forming a seal between the flaps <NUM> and <NUM>. After the flaps <NUM> and <NUM> are sealed, the film <NUM> provides a moisture barrier to the pack <NUM> to keep the contents in the central compartment at the appropriate humidity level until the film <NUM> is removed from the pack <NUM>.

In various embodiments, the invention described herein relates to a method of making a cigarette pack wrapped in the film <NUM> (e.g., cigarette pack <NUM> as shown in <FIG>). Referring to <FIG>, a flow diagram of a method <NUM> of making a cigarette pack wrapped in the film <NUM> is shown according to an example embodiment. The method <NUM> may be performed by a cigarette pack manufacturing machine.

Claim 1:
A package (<NUM>) comprising:
a main body (<NUM>) formed of a paper material;
a top (<NUM>) formed of the paper material;
a central compartment (<NUM>) formed by the top and the main body (<NUM>; <NUM>); and
a wrapping formed of a film (<NUM>) comprising polylactic acid and comprising:
a first layer (<NUM>) comprising a first material having a first melting point;
a second layer (<NUM>) comprising a second material having a second melting point, the second melting point is lower than the first melting point, a first side of the second layer (<NUM>) bonded to a first side of the first layer (<NUM>);
a third layer (<NUM>) comprising the second material, a first side of the third layer (<NUM>) bonded to a second side of the first layer (<NUM>), the second side of the first layer (<NUM>) opposite the first side of the first layer (<NUM>); and
a moisture barrier coating (<NUM>) applied to a second side of the second layer (<NUM>) and a second side of the third layer (<NUM>) opposite the first side of the first layer (<NUM>) through an atomic layer deposition process, the moisture barrier coating (<NUM>) comprising a metal-oxide and having a thickness of <NUM> - <NUM>.