Cellulose structures, cellulose containers, and methods of making same

Abstract

A cellulosic structure includes a cellulosic plate substrate having a first side and a second side and an outermost heat seal layer on the first side of the cellulosic plate substrate. The oxygen barrier resin layer and the metal oxide coated polymer barrier film are between the first side of the cellulosic plate substrate and the outermost heat seal layer.

Description

[0001] priority

[0002] This application claims priority to US Ser. No. 63 / 353,746, filed June 20, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of high barrier cellulosic structures for use in cellulosic containers. Background Art

[0004] Paper-based containers are typically formed from a blank, such as a paperboard blank. The paperboard blank is die-cut into a desired profile, and the blank is then formed into a desired container shape. For example, the blank may be rolled around a mandrel to form a cylindrical or frusto-conical container body. A bottom member is typically connected to the container body to surround the lower end of the container body. After the container is filled, a cover member is typically connected to the container body to completely surround the container.

[0005] The contents of paper-based containers can be exposed to oxygen, moisture, and / or light that penetrate the walls of such containers. Depending on the contents of the container, penetration of oxygen, moisture, and / or light can lead to product degradation. For example, food products can deteriorate faster and thus have a significantly shortened shelf life when packaged in containers that do not significantly exclude oxygen, moisture, and light.

[0006] Therefore, paper-based containers are formed from materials with barrier properties. For example, conventional paper-based containers often have a metal barrier layer incorporated into a paperboard blank used to form a food container that is sensitive to degradation caused by oxygen, moisture, and light penetration. However, the introduction of the metal barrier layer limits the recyclability of paper-based containers.

[0007] There is a need for a new recyclable material that still has the same or similar barrier properties as these conventional paper-based containers combined with a metal barrier layer.

[0008] Therefore, those skilled in the art continue to conduct research and development in the field of cellulose structures for cellulose containers and methods for making the same Summary of the invention

[0009] Cellulose structures are disclosed.

[0010] In one example, the disclosed cellulose structure includes a cellulose sheet substrate having a first side and a second side and an outermost heat seal layer on the first side of the cellulose sheet substrate. An oxygen barrier resin layer and a metal oxide coated polymer barrier film are between the first side of the cellulose sheet substrate and the outermost heat seal layer.

[0011] A cellulose container is also disclosed.

[0012] In one example, a cellulose container is disclosed that includes a sidewall component, a bottom component surrounding a first end of the sidewall component, and a lid component surrounding a second end of the sidewall component. The sidewall component has a first end and a second end. The sidewall component includes a cellulose sheet substrate having a first side and a second side, an outermost heat seal layer on the first side of the cellulose sheet substrate; an oxygen barrier resin layer between the first side of the cellulose sheet substrate and the outermost heat seal layer, and a metal oxide coated polymer barrier film between the first side of the cellulose sheet substrate and the outermost heat seal layer.

[0013] Also disclosed are methods for making the cellulosic structures.

[0014] In one example, the disclosed method for making a cellulosic structure includes (1) extruding an oxygen barrier resin layer onto a first side of a cellulosic sheet substrate; (2) placing a metal oxide coated polymer barrier film on the extruded oxygen barrier resin layer; and (3) applying a heat seal layer on the metal oxide coated polymer barrier film.

[0015] In another example, a method for making a cellulosic structure is disclosed that includes (1) applying a liquid adhesive oxygen barrier resin layer to a first side of a cellulosic sheet substrate; (2) placing a metal oxide coated polymer barrier film on the liquid adhesive oxygen barrier resin layer; and (3) applying a heat seal layer on the metal oxide coated polymer barrier film.

[0016] Other examples of the disclosed cellulosic structures, cellulosic containers, and methods of making the same will become apparent from the following detailed description, drawings, and appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a representative diagram of a cellulose structure according to one example of the present specification.

[0018] Figure 2 is a diagram of a side wall member of a cellulose container according to one example of the present specification.

[0019] Figure 3 is a diagram of a cellulose container according to one example of the present specification. DETAILED DESCRIPTION

[0020] Objectives of the present invention include developing a recyclable material having the same or similar barrier properties as a metal barrier layer by applying an ultra-high barrier film on a cellulose board substrate.

[0021] Metal oxide coated polymer barrier films can be laminated to a cellulose board substrate to achieve ultra-high barrier properties to oxygen and moisture. However, when such a laminate is folded to 90 or 180 degrees, the barrier properties decrease, particularly the oxygen permeability and water vapor permeability increase. The oxygen barrier properties are more severely impaired than the moisture barrier properties. In the method of the present specification, it is determined that when an oxygen barrier resin layer is used as a tie layer to laminate a metal oxide coated film, the oxygen barrier properties are significantly improved, even after the laminate is folded 90 and 180 degrees. Such folding of the laminate is expected to occur during packaging conversion, so the barrier integrity after folding is critical.

[0022] The cellulose structure disclosed in the present specification includes a cellulose board substrate having a first side and a second side, an outermost heat seal layer on the first side of the cellulose board substrate, and an oxygen barrier resin layer and a metal oxide coated polymer barrier film between the outermost heat seal layer and the first side of the cellulose board substrate. The oxygen barrier resin layer may be located between the first side of the cellulose board substrate and the metal oxide coated polymer barrier film, or the metal oxide coated polymer barrier film may be located between the first side of the cellulose board substrate and the oxygen barrier resin layer. The presence of the oxygen barrier resin layer inhibits (e.g., reduces or avoids) oxygen barrier degradation of the cellulose board substrate when the cellulose board substrate is folded. Additional layers may be included in the disclosed cellulose structure without departing from the scope of the present disclosure.

[0023] In one aspect, the second side of the cellulose sheet substrate is free of a heat sealable layer. In another aspect, the second side of the cellulose sheet substrate is free of a polyolefin. In another aspect, the second side of the cellulose sheet substrate is free of a polymer. In another aspect, the second side of the cellulose sheet substrate is uncoated.

[0024] refer to Figure 1 , an illustrative example of a disclosed cellulosic structure 10 of the present specification includes a cellulose sheet substrate 12 having a first side 14 and a second side 16, an oxygen barrier resin layer 18 on the first side 14 of the cellulose sheet substrate 12, a metal oxide coated polymer barrier film 20 on the oxygen barrier resin layer 18, and an outermost heat seal layer 22 on the metal oxide coated polymer barrier film 20. In an alternative example, the positions of the oxygen barrier resin layer 18 and the metal oxide coated polymer barrier film 20 may be reversed, in which case the tie layer is preferably disposed between the metal oxide coated polymer barrier film 20 and the first side 14 of the cellulose sheet substrate 12. Other examples of additional layers between the outermost heat seal layer 22 and the first side 14 of the cellulose sheet substrate 12 are included in the present specification.

[0025] The cellulose board substrate 12 of the present specification is not limited and may include any cellulose board substrate 12 formed of a cellulose material. In an exemplary aspect, the cellulose board substrate 12 may include or may be a paperboard substrate, particularly a single-ply paperboard substrate.

[0026] In some examples, the cellulose board substrate 12 may be characterized as having a maximum transmittance (%T). However, the cellulose structures disclosed in the present specification are not limited to cellulose board substrates 12 having a defined maximum transmittance (%T). In one aspect, the maximum transmittance (%T) of the cellulose board substrate 12 in the range of 300-700 nm may be 4.0% or less, such as 3.0% or less, 2.0% or less, 1.0% or less, 0.5% or less, or 0.3% or less. The maximum transmittance is tested at 23 degrees Celsius. Therefore, a cellulose board substrate with a low maximum transmittance helps resist light penetration into a container formed therefrom, which can lead to product degradation. The maximum transmittance of the cellulose board substrate may be caused by a combination of factors, including the lignin content of the cellulose board substrate, the caliper thickness of the cellulose board substrate, and the basis weight of the cellulose board substrate. By reducing the maximum transmittance of the cellulose board substrate, the cellulose board substrate of the present application can eliminate or reduce the need for other devices for resisting light penetration.

[0027] In one aspect, the cellulose board substrate 12 can have a lignin content of 2% or more by weight, such as 4% or more, 6% or more, 8% or more, 10% or more, 12% or more, 14% or more, 16% or more, or 18% or more. The lignin content of the cellulose board substrate helps resist light penetration into the container formed therefrom, which can cause product degradation. Lignin can act as a chromophore, which acts as a light barrier. By increasing the lignin content of the cellulose board substrate, the maximum transmittance of the cellulose board substrate is reduced.

[0028] In one aspect, the cellulose board substrate 12 can have a density of between 180 and 300 lbs / 3000 ft 2 Basis weights in a range, e.g. 210 to 260 lbs / 3000 ft 2 In one example, a 20 pt. board having a basis weight of 240 lbs. / 3000 ft2 may be used. The basis weight of the cellulose board substrate helps to resist light penetration into a container formed therefrom, which may result in product degradation. By increasing the basis weight of the cellulose board substrate, the maximum transmittance of the cellulose board substrate is reduced. In other aspects, the basis weight of the cellulose board substrate may be less than 180 lbs. / 3000 ft2. 2 or greater than 290 lbs / 3000ft 2 .

[0029] In one aspect, the cellulose board substrate 12 can have a thickness in the range of 10 to 36 points, such as 14 to 30 points or 18 to 22 points. The thickness of the cellulose board substrate helps resist light penetration into the container formed therefrom, which can lead to product degradation. By increasing the thickness of the cellulose board substrate, the maximum transmittance of the cellulose board substrate is reduced. In other aspects, the thickness of the cellulose board substrate can be less than 14 points or greater than 30 points. The thickness of the cellulose board substrate can depend on various factors, such as the density of the cellulose board substrate. As used herein, 1 point is equal to 0.001 inches, which is equal to 25.4 micrometers (μm).

[0030] The oxygen barrier resin layer 18 serves as an oxygen barrier layer. The oxygen barrier resin layer 18 may include or be an oxygen barrier polymer extruded or coated onto the cellulose sheet substrate 12. Examples of suitable oxygen barrier polymers are polyvinyl alcohol (PVOH) and ethylene vinyl alcohol (EVOH). Another example of a suitable oxygen barrier polymer is nylon. In yet another example, the oxygen barrier resin layer 18 may be (or may include) thermoplastic starch.

[0031] In one exemplary aspect, the oxygen barrier resin layer 18 can be melt extruded at an elevated temperature to connect the metal oxide coated polymer barrier film 20 to the cellulose sheet substrate 12 without requiring an additional tie layer between the oxygen barrier resin layer 18 and the metal oxide coated polymer barrier film 20. In another exemplary aspect, the oxygen barrier resin layer 18 can have two (or more) locations: (1) between the metal oxide coated polymer barrier film 20 and the cellulose sheet substrate 12, and (2) also on the opposite / reverse side of the metal oxide coated polymer barrier film 20. In one exemplary aspect, the oxygen barrier resin layer 18 can be an aqueous adhesive that is applied to the cellulose sheet substrate 12 to adhere the metal oxide coated polymer barrier film 20 to the cellulose sheet substrate 12 without requiring an additional tie layer between the oxygen barrier resin layer 18 and the metal oxide coated polymer barrier film 20. In yet another exemplary aspect, the oxygen barrier resin layer 18 can be disposed on the cellulose sheet substrate 12 in any form, and the metal oxide coated polymer barrier film 20 can be laminated to the cellulose sheet substrate 12 using a tie layer or in any other suitable manner. Alternatively, the positions of the oxygen barrier resin layer 18 and the metal oxide coated polymer barrier film 20 can be reversed, in which case the tie layer can be disposed between the metal oxide coated polymer barrier film 20 and the first side 14 of the cellulose sheet substrate 12. In the case of a tie layer, the tie layer can include any suitable tie layer. For example, the tie layer can include or can be a polyolefin, such as a low density polyethylene. The tie layer can be melt extruded at an elevated temperature. In another aspect, the tie layer can include or be, for example, an aqueous adhesive.

[0032] The metal oxide coated polymer barrier film 20 is a polymer film having a metal oxide coating thereon. The metal oxide coated polymer barrier film 20 serves as a barrier layer to oxygen and moisture. The metal oxide coated polymer barrier film 20 may include or may be, for example, an aluminum oxide coated polymer barrier film. As another specific example, the metal oxide coated polymer barrier film 20 may include or may be a silicon oxide coated polymer barrier film. The polymer of the metal oxide coated polymer barrier film 20 is not limited. In one aspect, the polymer of the metal oxide coated polymer barrier film 20 may include or be a polyester or a polyolefin. On the other hand, the polymer of the metal oxide coated polymer barrier film 20 may include or may be polyethylene terephthalate. The presence of the metal oxide coated polymer barrier film 20 helps prevent oxygen and moisture from entering the interior of the container formed by the cellulose structure 10. However, the metal oxide coated polymer barrier film 20 may be transparent and does not prevent light from passing through. Thus, in the case of a cellulose board substrate 12 having a defined maximum transmittance (%T), the combination of a cellulose board substrate 12 having a defined maximum transmittance (%T) and a metal oxide coated polymer barrier film 20 can provide resistance to the passage of oxygen, moisture, and light into the interior of a container formed by the cellulose structure 10.

[0033] The disclosed metal oxide coated polymer barrier film 20 is formed as a metal oxide coated polymer barrier film 20 before forming the cellulose structure 10 of the present specification. The disclosed metal oxide coated polymer barrier film 20 can be formed by coating a polymer (e.g., polyethylene terephthalate) film with a metal oxide. The metal oxide coated polymer barrier film 20 can be selected from commercially available metal oxide coated polymer barrier films 20 from various sources.

[0034] The outermost heat seal layer 22 may include or may be, for example, low density polyethylene. On the other hand, the outermost heat seal layer 22 may include or may be from, for example, a polyolefin homopolymer, a copolymer, a terpolymer, and a family of functionalized and modified forms thereof. On the other hand, the outermost heat seal layer 22 may include or may be ethylene methyl acrylate (EMA). In other expressions, the outermost heat seal layer 22 may be formed by other materials that can be activated (for example, with heat, ultrasonic energy, radiation, etc.) to form a seal. The combination of sealing materials may be used to form a heat seal layer 22. In a specific example, the heat seal layer 22 may include a monolayer or a co-extruded structure.

[0035] In one aspect, the cellulosic structure 10 has a maximum transmittance (%T) in the range of 300-700 nm of 1.0% or less, e.g., 0.5% or less, 0.3% or less, 0.2% or less, 0.1% or less, or 0.05% or less. The maximum transmittance of the cellulosic structure can be controlled by reducing the maximum transmittance of the cellulose sheet substrate or by other means to prevent light from penetrating. By reducing the maximum transmittance of the cellulosic structure 10, the contents of a container formed therefrom can be protected from degradation by light. By reducing the maximum transmittance of the cellulosic structure 10, the present description can eliminate the use of metal foil or pigments such as carbon black, thereby providing a recyclable high barrier cellulosic structure for forming a cellulosic container.

[0036] In another aspect, the cellulosic structure 10 can have an oxygen transmission rate of less than 0.1 cc / m2 / day at 1 atm. In another aspect, the cellulosic structure 10 can have a water vapor transmission rate of less than 0.1 g / m2 / day.

[0037] In another aspect, the cellulosic structure 10 can have at least 80% by weight cellulose content, such as at least 85% by weight cellulose content, or at least 90% by weight cellulose content. The remainder of the cellulosic structure can include or be a tie layer, a metal oxide coated polymer, and a heat seal layer or additional coating.

[0038] In one aspect, the cellulosic structure 10 can be formed by an extrusion lamination process. In the extrusion lamination process, the oxygen barrier resin layer 18 can be used as a tie layer to bond the metal oxide coated polymer barrier film 20 to the first side 14 of the cellulose sheet substrate 12. Thus, the oxygen barrier resin layer 18 can be extruded onto the first side 14 of the cellulose sheet substrate 12, and the metal oxide coated polymer barrier film 20 can be positioned on the extruded oxygen barrier resin layer 18, and then the extruded oxygen barrier resin layer 18 is cooled to bond the metal oxide coated polymer barrier film 20 to the first side 14 of the cellulose sheet substrate 12.

[0039] Alternatively, an additional tie layer may be used to bond the metal oxide coated polymer barrier film 20 to the first side 14 of the cellulose sheet substrate 12. Thus, an additional tie layer may be extruded onto the first side 14 of the cellulose sheet substrate 12, and the metal oxide coated polymer barrier film 20 may be disposed on the extruded tie layer, and the extruded tie layer may then be cooled to bond the metal oxide coated polymer barrier film 20 to the first side 14 of the cellulose sheet substrate 12. In one aspect, the oxygen barrier resin layer 18 may be located between the first side 14 of the cellulose sheet substrate 12 and the extruded tie layer. In one aspect, the oxygen barrier resin layer 18 may be located between the metal oxide coated polymer barrier film 20 and the outermost heat seal layer 22.

[0040] In one aspect, the cellulosic structure 10 can be formed by an adhesive coating process. In the adhesive coating process, the oxygen barrier resin layer 18 can be used as a tie layer to bond the metal oxide coated polymer barrier film 20 to the first side 14 of the cellulose sheet substrate 12. Thus, the oxygen barrier resin layer 18 can be applied as a liquid adhesive to the first side 14 of the cellulose sheet substrate 12, and the metal oxide coated polymer barrier film 20 can be positioned on the oxygen barrier resin layer 18 coating, and then the oxygen barrier resin layer 18 coating is dried to bond the metal oxide coated polymer barrier film 20 to the first side 14 of the cellulose sheet substrate 12.

[0041] Alternatively, an additional tie layer may be used to bond the metal oxide coated polymer barrier film 20 to the first side 14 of the cellulose sheet substrate 12. Thus, the additional tie layer may be applied to the first side 14 of the cellulose sheet substrate 12 as a liquid adhesive, and the metal oxide coated polymer barrier film 20 may be disposed on the applied tie layer, and the applied tie layer may then be dried to bond the metal oxide coated polymer barrier film 20 to the first side 14 of the cellulose sheet substrate 12. In one aspect, the oxygen barrier resin layer 18 may be located between the first side 14 of the cellulose sheet substrate 12 and the extruded tie layer. In one aspect, the oxygen barrier resin layer 18 may be located between the metal oxide coated polymer barrier film 20 and the outermost heat seal layer 22.

[0042] The coated cellulose structure preferably has a maximum transmittance and can be used to form containers for foods that are sensitive to degradation due to oxygen, moisture and light penetration. Despite folding / bending the substrate, the coated cellulose structure maintains an adequate oxygen barrier. Even when the substrate is folded or bent, degradation of the oxygen barrier is suppressed (e.g., reduced or avoided) at the folded or bent area. The structural integrity of the oxygen barrier is maintained (or at least maintained at a level sufficient to effectively serve as an oxygen barrier) in the folded or bent area of ​​the substrate. For conventional techniques and paper-based substrates that use metal oxide-coated films such as AlOx-coated PET as oxygen barriers, cracks or breakpoints are formed in the layer / barrier layer along or adjacent to the fold line. For the coated cellulose structures of the present specification, degradation of the oxygen barrier caused by the formation of such cracks / breaks along or adjacent to the fold line is suppressed (e.g., reduced or avoided).

[0043] In one aspect, the cellulosic structure 10 has an oxygen transmission rate of less than 1.0 cc / m2 / day at 1 atm after being folded to 90 degrees when tested at 23°C and 50% relative humidity. In another aspect, the cellulosic structure 10 has an oxygen transmission rate of less than 0.5 cc / m2 / day at 1 atm after being folded to 90 degrees when tested at 23°C and 50% relative humidity. In another aspect, the cellulosic structure 10 has an oxygen transmission rate of less than 0.1 cc / m2 / day at 1 atm after being folded to 90 degrees when tested at 23°C and 50% relative humidity.

[0044] In one aspect, the cellulosic structure 10 has an oxygen transmission rate of less than 1.0 cc / m2 / day at 1 atm after being folded to 180 degrees when tested at 23°C and 50% relative humidity. In another aspect, the cellulosic structure 10 has an oxygen transmission rate of less than 0.5 cc / m2 / day at 1 atm after being folded to 180 degrees when tested at 23°C and 50% relative humidity. In yet another aspect, the cellulosic structure 10 has an oxygen transmission rate of less than 0.1 cc / m2 / day at 1 atm after being folded to 180 degrees when tested at 23°C and 50% relative humidity.

[0045] In one aspect, the cellulosic structure 10 has a water vapor transmission rate of less than 1.0 g / m2 / day after being folded to 90 degrees when tested at 23°C and 50% relative humidity. In another aspect, the cellulosic structure 10 has a water vapor transmission rate of less than 0.5 g / m2 / day after being folded to 90 degrees when tested at 23°C and 50% relative humidity. In yet another aspect, the cellulosic structure 10 has a water vapor transmission rate of less than 0.1 g / m2 / day after being folded to 90 degrees when tested at 23°C and 50% relative humidity.

[0046] In one aspect, the cellulosic structure 10 has a water vapor transmission rate of less than 1.0 g / m2 / day after being folded to 180 degrees when tested at 23°C and 50% relative humidity. In another aspect, the cellulosic structure 10 has a water vapor transmission rate of less than 0.5 g / m2 / day after being folded to 180 degrees when tested at 23°C and 50% relative humidity. In another aspect, the cellulosic structure 10 has a water vapor transmission rate of less than 0.1 g / m2 / day after being folded to 180 degrees when tested at 23°C and 50% relative humidity.

[0047] refer to Figure 2 and 3, a container 100 formed from a cellulosic structure 10 is also disclosed. In one expression, the container 100 includes a sidewall member 101 having a first end and a second end, a bottom member 102 surrounding the first end of the sidewall member, and a lid member 103 surrounding the second end of the sidewall member. The sidewall member includes a cellulose sheet substrate 12 having a first side 14 and a second side 16, an oxygen barrier resin layer 18 on the first side 14 of the cellulose sheet substrate 12, a metal oxide coated polymer barrier film 20 on the oxygen barrier resin layer 18, and an outermost heat seal layer 22 on the metal oxide coated polymer barrier film 20. The positions of the oxygen barrier resin layer 18 and the metal oxide coated polymer barrier film 20 may be reversed, in which case it is preferred that a tie layer be provided between the metal oxide coated polymer barrier film 20 and the first side 14 of the cellulose sheet substrate 12. Further examples are also included in the present specification, including an additional layer between the outermost heat seal layer 22 and the first side 14 of the cellulose sheet substrate 12.

[0048] The side wall member 101 can be formed by, for example, die cutting the disclosed cellulose structure 10 ( Figure 1 ) sheet to form a sidewall blank with a desired profile (e.g., trapezoidal or rectangular). Then, the sidewall blank is formed into a desired sidewall component shape. In the example shown, the sidewall blank is bent 90 degrees. In alternative container examples, the sidewall blank can be bent 180 degrees. The outermost heat seal layer 22 can be activated to seal the sidewall components 101 together. The bottom component 102 is typically connected to the sidewall component 101 to surround the lower end of the sidewall component 101. After filling the container, the cover component 103 is typically connected to the sidewall component 101 to completely surround the container. The outermost heat seal layer 22 can be activated to seal the sidewall component 101, the bottom component 102 and the cover component 103 together. The bottom component 102 or the cover component 103 can be formed by the disclosed cellulose structure 10, or can be formed by different materials.

[0049] Experimental example

[0050] In the control example, a 20pt. CustomKote LS board was laminated with an AlOx coated PET barrier film using an LDPE tie layer. CustomKote is a coated natural kraft (CNK) board. The resulting laminate had the following structure: paperboard / LDPE / AlOx coated PET / heat seal layer, which had an average oxygen transmission rate (OTR) of 0.06cc / m^2.day at 23C / 50%RH, but when folded to 90 and 180 degree angles, the average oxygen transmission rate at 23C / 50%RH became 1.6 and 2.4cc / m^2.day, so the oxygen barrier performance deteriorated, and the OTR increased to 40 times after folding at 180 degrees. The average water vapor transmission rate (MVTR) of the board is 0.12 g / m^2.day at 23C / 75%RH. After folding at 90 and 180 degrees, the average water vapor transmission rate (MVTR) becomes 0.2 and 0.3 g / m^2.day.

[0051] In a second example, a 20 pt. CustomKote LS sheet was laminated to an AlOx coated PET barrier film using a water-based PVOH adhesive. This sheet had the following structure: paperboard / adh.PVOH / AlOx coated PET. This unfolded sheet had an average OTR of 0.01 cc / m^2.day at 23C / 50% RH, but when folded at 90 and 180 degree angles, the average oxygen transmission rates at 23C / 50% RH were 0.07 and 0.11 cc / m^2.day, respectively. After folding at 180 degrees, the average OTR increased to 11 times, so the barrier performance was significantly improved compared to the control example. At 23C / 75% RH, the MVTR performance of this structure after folding at 90 and 180 degrees was 0.2 and 0.3 g / m^2.day, respectively, which is similar to the control example.

[0052] In a third example, when the same AlOx coated PET barrier film was laminated to a board using extruded PVOH, it was also found that the oxygen barrier was improved compared to the control in the folded samples. This board had the structure; 16pt.SBS board / ext.PVOH / AlOx PET, and at 23C / 50%RH, the average OTR of this structure after folding at 90 degrees and 180 degrees was 0.03 and 0.08cc / m^2.day, respectively, which confirms the benefit of using PVOH as a tie layer, which also provides a supplemental oxygen barrier. At 23C / 75%RH, the MVTR performance of this structure after folding at 90 degrees and 180 degrees was 0.5g / m^2.day.

[0053] In a fourth embodiment, the MVTR performance of the above structure after folding at 180 degrees is improved after adding a heat seal layer. The new structure is 16pt.SBS sheet / ext.PVOH / AlOx PET / heat seal layer. This heat seal layer includes low density polyethylene (LDPE). The MVTR performance of this structure after folding at 180 degrees at 23C / 75%RH is 0.1g / m^2.day. This embodiment shows that a balance of OTR and MVTR can be achieved through this new inventive step.

[0054] In addition, the present disclosure includes examples according to the following clauses:

[0055] Item 1. A cellulosic structure comprising: a cellulose sheet substrate having a first side and a second side; an outermost heat seal layer on the first side of the cellulose sheet substrate; an oxygen barrier resin layer between the first side of the cellulose sheet substrate and the outermost heat seal layer; and a metal oxide-coated polymer barrier film between the first side of the cellulose sheet substrate and the outermost heat seal layer.

[0056] Item 2. The cellulose structure of Item 1, wherein the cellulose sheet substrate has a maximum transmittance (%T) of 4.0% or less in the range of 300-700 nm.

[0057] Item 3. The cellulose structure of Item 1, wherein the cellulose sheet substrate has a maximum transmittance (%T) of 3.0% or less in the range of 300-700 nm.

[0058] Item 4. The cellulose structure of Item 1, wherein the cellulose sheet substrate has a maximum transmittance (%T) of 2.0% or less in the range of 300-700 nm.

[0059] Item 5. The cellulose structure of Item 1, wherein the cellulose sheet substrate has a maximum transmittance (%T) of 1.0% or less in the range of 300-700 nm.

[0060] Item 6. The cellulose structure of Item 1, wherein the cellulose sheet substrate has a maximum transmittance (%T) of 0.5% or less in the range of 300-700 nm.

[0061] Item 7. The cellulose structure of Item 1, wherein the cellulose sheet substrate has a maximum transmittance (%T) of 0.3% or less in the range of 300-700 nm.

[0062] Clause 8. The cellulosic structure of any preceding clause, wherein the cellulosic board substrate has a lignin content of 2 wt% or more.

[0063] Clause 9. The cellulosic structure of any preceding clause, wherein the cellulosic board substrate has a lignin content of 4 wt% or more.

[0064] Clause 10. The cellulosic structure of any preceding clause, wherein the cellulosic board substrate has a lignin content of 6 wt% or more.

[0065] Clause 11. The cellulosic structure of any preceding clause, wherein the cellulosic board substrate has a lignin content of 8 wt% or more.

[0066] Clause 12. The cellulosic structure of any preceding clause, wherein the cellulosic board substrate has a lignin content of 10 wt% or more.

[0067] Clause 13. The cellulosic structure of any preceding clause, wherein the cellulosic board substrate has a lignin content of 12 wt% or more.

[0068] Clause 14. The cellulosic structure of any preceding clause, wherein the cellulosic board substrate has a lignin content of 14 wt% or more.

[0069] Clause 15. The cellulosic structure of any preceding clause, wherein the cellulosic board substrate has a lignin content of 16 wt% or more.

[0070] Clause 16. The cellulosic structure of any preceding clause, wherein the cellulosic board substrate has a lignin content of 18 wt% or more.

[0071] Clause 17. The cellulose structure of any preceding clause, wherein the cellulose board substrate has a density of 180 to 300 lbs / 3000 ft 2 The basis weight.

[0072] Clause 18. The cellulose structure of any preceding clause, wherein the cellulose board substrate has a 2 The basis weight.

[0073] Clause 19. The cellulosic structure of any preceding clause, wherein the cellulosic sheet substrate has a thickness of from 10 to 36 points.

[0074] Clause 20. The cellulosic structure of any preceding clause, wherein the cellulosic sheet substrate has a thickness of 14 to 30 points.

[0075] Clause 21. The cellulosic structure of any preceding clause, wherein the cellulose sheet substrate has a thickness of 18 to 22 points.

[0076] Clause 22. The cellulosic structure of any preceding clause, wherein the oxygen barrier resin layer comprises polyvinyl alcohol (PVOH).

[0077] Item 23. The cellulosic structure of any preceding item, wherein the oxygen barrier resin layer comprises ethylene vinyl alcohol (EVOH).

[0078] Clause 24. The cellulosic structure of any preceding clause, wherein the oxygen barrier resin layer comprises nylon.

[0079] Clause 25. The cellulosic structure of any preceding clause, wherein the oxygen barrier resin layer comprises thermoplastic starch.

[0080] Clause 26. The cellulose structure of any preceding clause, wherein the metal oxide coated polymer barrier film comprises at least one of aluminum oxide and silicon oxide.

[0081] Clause 27. The cellulosic structure of any preceding clause, wherein the metal oxide coated polymer barrier film comprises at least one of a polyester or a polyolefin.

[0082] Clause 28. The cellulosic structure of any preceding clause, wherein the metal oxide coated polymer barrier film comprises polyethylene terephthalate.

[0083] Clause 29. The cellulosic structure of any preceding clause, wherein the outermost heat seal layer comprises low density polyethylene.

[0084] Clause 30. The cellulosic structure of any preceding clause, wherein the outermost heat seal layer comprises ethylene methyl acrylate (EMA).

[0085] Clause 31. The cellulosic structure of any preceding clause, wherein the oxygen barrier resin layer is between the first side of the cellulosic sheet substrate and the metal oxide coated polymer barrier film.

[0086] Clause 32. The cellulosic structure of any preceding clause, wherein the metal oxide coated polymer barrier film is between the first side of the cellulosic sheet substrate and the oxygen barrier resin layer.

[0087] Item 33. The cellulosic structure of Item 32, further comprising a tie layer between the first side of the cellulosic sheet substrate and the metal oxide coated polymer barrier film.

[0088] Clause 34. The cellulose structure of any preceding clause, wherein the cellulose structure has a maximum transmittance (%T) in the range of 300-700 nm of 1.0% or less.

[0089] Clause 35. The cellulose structure of any preceding clause, wherein the cellulose structure has a maximum transmittance (%T) in the range of 300-700 nm of 0.5% or less.

[0090] Clause 36. The cellulose structure of any preceding clause, wherein the cellulose structure has a maximum transmittance (%T) in the range of 300-700 nm of 0.3% or less.

[0091] Clause 37. The cellulose structure of any preceding clause, wherein the cellulose structure has a maximum transmittance (%T) in the range of 300-700 nm of 0.2% or less.

[0092] Clause 38. The cellulose structure of any preceding clause, wherein the cellulose structure has a maximum transmittance (%T) in the range of 300-700 nm of 0.1% or less.

[0093] Clause 39. The cellulose structure of any preceding clause, wherein the cellulose structure has a maximum transmittance (%T) in the range of 300-700 nm of 0.05% or less.

[0094] Clause 40. The cellulosic structure of any preceding clause, wherein the cellulosic structure has a cellulose content of at least 80% by weight.

[0095] Clause 41. The cellulosic structure of any preceding clause, wherein the cellulosic structure has a cellulose content of at least 85% by weight.

[0096] Clause 42. The cellulosic structure of any preceding clause, wherein the cellulosic structure has a cellulose content of at least 90% by weight.

[0097] Clause 43. The cellulosic structure of any preceding clause, wherein the cellulosic structure has an oxygen transmission rate of less than 1 cc / m2 / day at 1 atm after being folded to 90 degrees.

[0098] Clause 44. The cellulosic structure of any preceding clause, wherein the cellulosic structure has an oxygen transmission rate of less than 0.5 cc / m2 / day at 1 atm after being folded to 90 degrees.

[0099] Clause 45. The cellulosic structure of any preceding clause, wherein the cellulosic structure has an oxygen transmission rate of less than 1 cc / m2 / day at 1 atm after folding to 180 degrees.

[0100] Clause 46. The cellulosic structure of any preceding clause, wherein the cellulosic structure has an oxygen transmission rate of less than 0.5 cc / m2 / day at 1 atm after folding to 180 degrees.

[0101] Clause 47. The cellulosic structure of any preceding clause, wherein the cellulosic structure has a water vapor transmission rate of less than 1 g / m2 / day after being folded to 90 degrees.

[0102] Clause 48. The cellulosic structure of any preceding clause, wherein the cellulosic structure has a water vapor transmission rate of less than 0.5 g / m2 / day after being folded to 90 degrees.

[0103] Clause 49. The cellulosic structure of any preceding clause, wherein the cellulosic structure has a water vapor transmission rate of less than 1 g / m2 / day after folding to 180 degrees.

[0104] Clause 50. The cellulosic structure of any preceding clause, wherein the cellulosic structure has a water vapor transmission rate of less than 0.5 g / m2 / day after folding to 180 degrees.

[0105] Item 51. A cellulose container comprising: a side wall component having a first end and a second end, the side wall component comprising: a cellulose board substrate having a first side and a second side; an outermost heat seal layer on the first side of the cellulose board substrate; an oxygen barrier resin layer between the first side of the cellulose board substrate and the outermost heat seal layer; and a metal oxide-coated polymer barrier film between the first side of the cellulose board substrate and the outermost heat seal layer; a bottom component, the bottom component surrounding the first end of the side wall component; and a cover component, which surrounds the second end of the side wall component.

[0106] Item 52. The cellulose container of Item 51, wherein the cellulose container maintains an adequate oxygen barrier despite folding / bending of the substrate.

[0107] Item 53. The cellulose container of Item 51 or Item 52, wherein when the substrate is folded or bent, degradation of the oxygen barrier is inhibited in the folded or bent region.

[0108] Item 54. The cellulose container of any of Items 51-53, wherein the integrity of the oxygen barrier is maintained at least to a level sufficient to effectively function as an oxygen barrier in the folded or bent regions of the substrate.

[0109] Clause 55. The cellulose container of any of Clauses 51-54, wherein degradation of the oxygen barrier caused by the formation of cracks or breaks in the oxygen barrier layer of the cellulose container is inhibited along or adjacent to a fold line used to form the cellulose container.

[0110] Clause 56. The cellulosic container of any of Clauses 51-55, containing a food susceptible to light-induced deterioration.

[0111] Item 57. The cellulose container of any of Items 51-56, wherein the cellulose sheet substrate has a maximum transmittance (%T) of 4.0% or less in the range of 300-700 nm.

[0112] Item 58. The cellulose container of any of Items 51-56, wherein the cellulose sheet substrate has a maximum transmittance (%T) of 3.0% or less in the range of 300-700 nm.

[0113] Item 59. The cellulose container of any of Items 51-56, wherein the cellulose sheet substrate has a maximum transmittance (%T) of 2.0% or less in the range of 300-700 nm.

[0114] Item 60. The cellulose container of any of Items 51-56, wherein the cellulose sheet substrate has a maximum transmittance (%T) of 1.0% or less in the range of 300-700 nm.

[0115] Item 61. The cellulose container of any of Items 51-56, wherein the cellulose sheet substrate has a maximum transmittance (%T) of 0.5% or less in the range of 300-700 nm.

[0116] Item 62. The cellulose container of any of Items 51-56, wherein the cellulose sheet substrate has a maximum transmittance (%T) of 0.3% or less in the range of 300-700 nm.

[0117] Clause 63. The cellulosic container of any of Clauses 51-62, wherein the cellulosic board substrate has a lignin content of 2 wt% or more.

[0118] Clause 64. The cellulosic container of any of Clauses 51-62, wherein the cellulosic board substrate has a lignin content of 4 wt% or more.

[0119] Clause 65. The cellulosic container of any of Clauses 51-62, wherein the cellulosic board substrate has a lignin content of 6 wt% or more.

[0120] Clause 66. The cellulosic container of any of Clauses 51-62, wherein the cellulosic board substrate has a lignin content of 8 wt% or more.

[0121] Clause 67. The cellulosic container of any of Clauses 51-62, wherein the cellulosic board substrate has a lignin content of 10 wt% or more.

[0122] Clause 68. The cellulosic container of any of Clauses 51-62, wherein the cellulosic board substrate has a lignin content of 12 wt% or more.

[0123] Clause 69. The cellulosic container of any of Clauses 51-62, wherein the cellulosic board substrate has a lignin content of 14 wt% or more.

[0124] Clause 70. The cellulosic container of any of Clauses 51-62, wherein the cellulosic board substrate has a lignin content of 16 wt% or more.

[0125] Clause 71. The cellulosic container of any of Clauses 51-62, wherein the cellulosic board substrate has a lignin content of 18 wt% or more.

[0126] Clause 72. The cellulose container of any of clauses 51-71, wherein the cellulose board substrate has a 2 The basis weight.

[0127] Clause 73. The cellulose container of any of clauses 51-71, wherein the cellulose board substrate has a 2 The basis weight.

[0128] Clause 74. The cellulose container of any of Clauses 51-73, wherein the cellulose sheet substrate has a thickness of 10 to 36 points.

[0129] Clause 75. The cellulose container of any of Clauses 51-73, wherein the cellulose sheet substrate has a thickness of 14 to 30 points.

[0130] Clause 76. The cellulose container of any of Clauses 51-73, wherein the cellulose sheet substrate has a thickness of 18 to 22 points.

[0131] Clause 77. The cellulosic container of any of Clauses 51-76, wherein the oxygen barrier resin layer comprises polyvinyl alcohol (PVOH).

[0132] Clause 78. The cellulosic container of any of Clauses 51-77, wherein the oxygen barrier resin layer comprises ethylene vinyl alcohol (EVOH).

[0133] Clause 79. The cellulosic container of any of Clauses 51-78, wherein the oxygen barrier resin layer comprises nylon.

[0134] Clause 80. The cellulosic container of any of Clauses 51-79, wherein the oxygen barrier resin layer comprises thermoplastic starch.

[0135] Clause 81. The cellulose container of any of Clauses 51-80, wherein the metal oxide coated polymer barrier film comprises at least one of aluminum oxide and silicon oxide.

[0136] Clause 82. The cellulosic container of any of Clauses 51-81, wherein the metal oxide coated polymer barrier film comprises at least one of a polyester or a polyolefin.

[0137] Clause 83. The cellulose container of any of Clauses 51-82, wherein the metal oxide-coated polymer barrier film comprises polyethylene terephthalate.

[0138] Clause 84. The cellulosic container of any of Clauses 51-83, wherein the outermost heat seal layer comprises low density polyethylene.

[0139] Clause 85. The cellulose container of any of clauses 51-84, wherein the outermost heat seal layer comprises ethylene methyl acrylate (EMA).

[0140] Clause 86. The cellulosic container of any of Clauses 51-85, wherein the oxygen barrier resin layer is between the first side of the cellulosic sheet substrate and the metal oxide coated polymer barrier film.

[0141] Clause 87. The cellulose container of any of Clauses 51-86, wherein the metal oxide coated polymer barrier film is between the first side of the cellulose sheet substrate and the oxygen barrier resin layer.

[0142] Clause 88. The cellulosic container of Clause 87, further comprising a tie layer between the first side of the cellulose sheet substrate and the metal oxide coated polymer barrier film.

[0143] Item 89. The cellulose container of any of Items 51-88, wherein the sidewall member has a maximum transmittance (%T) of 1.0% or less in the range of 300-700 nm.

[0144] Clause 90. The cellulose container of any of Clauses 51-88, wherein the sidewall member has a maximum transmittance (%T) of 0.5% or less in the range of 300-700 nm.

[0145] Clause 91. The cellulose container of any of clauses 51-88, wherein the sidewall member has a maximum transmittance (%T) of 0.3% or less in the range of 300-700 nm.

[0146] Item 92. The cellulose container of any of Items 51-88, wherein the sidewall member has a maximum transmittance (%T) of 0.2% or less in the range of 300-700 nm.

[0147] Clause 93. The cellulose container of any of clauses 51-88, wherein the sidewall member has a maximum transmittance (%T) of 0.1% or less in the range of 300-700 nm.

[0148] Clause 94. The cellulose container of any of Clauses 51-88, wherein the sidewall component has a maximum transmittance (%T) of 0.05% or less in the range of 300-700 nm.

[0149] Clause 95. The cellulosic container of any of Clauses 51-94, wherein the sidewall member has a cellulose content of at least 80% by weight.

[0150] Clause 96. The cellulosic container of any of Clauses 51-94, wherein the sidewall member has a cellulose content of at least 85% by weight.

[0151] Clause 97. The cellulosic container of any of Clauses 51-94, wherein the sidewall member has a cellulose content of at least 90% by weight.

[0152] Clause 98. The cellulose container of any of clauses 51-97, wherein after being folded to 90 degrees, the sidewall component has an oxygen transmission rate of less than 1 cc / m2 / day at 1 atm.

[0153] Clause 99. The cellulose container of any of clauses 51-97, wherein after folding to 90 degrees, the sidewall component has an oxygen transmission rate of less than 0.5 cc / m2 / day at 1 atm.

[0154] Clause 100. The cellulose container of any of clauses 51-97, wherein after folding to 180 degrees, the sidewall component has an oxygen transmission rate of less than 1 cc / m2 / day at 1 atm.

[0155] Clause 101. The cellulose container of any of clauses 51-97, wherein after folding to 180 degrees, the sidewall component has an oxygen transmission rate of less than 0.5 cc / m2 / day at 1 atm.

[0156] Clause 102. The cellulose container of any of Clauses 51-101, wherein after folding to 90 degrees, the sidewall member has a water vapor transmission rate of less than 1 g / m2 / day.

[0157] Clause 103. The cellulose container of any of Clauses 51-101, wherein after being folded to 90 degrees, the sidewall member has a water vapor transmission rate of less than 0.5 g / m2 / day.

[0158] Clause 104. The cellulose container of any of Clauses 51-101, wherein after folding to 180 degrees, the sidewall member has a water vapor transmission rate of less than 1 g / m2 / day.

[0159] Clause 105. The cellulose container of any of Clauses 51-101, wherein the sidewall member has a water vapor transmission rate of less than 0.5 g / m2 / day after being folded to 180 degrees.

[0160] Item 106. A method for making a cellulosic structure, the method comprising: extruding an oxygen barrier resin layer onto a first side of a cellulosic sheet substrate; placing a metal oxide coated polymer barrier film on the extruded oxygen barrier resin layer; and applying a heat seal layer on the metal oxide coated polymer barrier film.

[0161] Item 107. A method for making a cellulosic structure, the method comprising: applying a liquid adhesive oxygen barrier resin layer to a first side of a cellulosic sheet substrate; placing a metal oxide coated polymer barrier film on the liquid adhesive oxygen barrier resin layer; and applying a heat seal layer on the metal oxide coated polymer barrier film.

[0162] Clause 108. A method for making a cellulosic container, the method comprising: folding the cellulosic structure of any of Clauses 1-50 to form a cellulosic container.

[0163] Item 109. The method of Item 108, wherein the cellulosic structure maintains an adequate oxygen barrier despite folding / bending of the substrate.

[0164] Clause 110. The method of Clause 108 or Clause 109, wherein when the substrate is folded or bent, degradation of the oxygen barrier is inhibited at the folded or bent area.

[0165] Clause 111. The method of any of Clauses 108-110, wherein the integrity of the oxygen barrier is maintained at least to a level sufficient to effectively function as an oxygen barrier at a folded or bent region of the substrate.

[0166] Clause 112. The method of any of Clauses 108-111, wherein degradation of the oxygen barrier caused by the formation of cracks or breaks in the oxygen barrier layer of the cellulosic container is inhibited along or adjacent a fold line used to form the cellulosic container.

[0167] Although various examples of the disclosed cellulosic structure for cellulosic containers and methods of making the same have been shown and described, modifications may occur to those skilled in the art upon reading the specification. The present application includes such modifications and is limited only by the scope of the claims.

Claims

1. A cellulose structure comprising: a cellulose sheet substrate having a first side and a second side; an outermost heat seal layer on the first side of the cellulose sheet substrate; an oxygen barrier resin layer between the first side of the cellulose sheet substrate and the outermost heat seal layer; and A metal oxide coated polymeric barrier film is between the first side of the cellulose sheet substrate and the outermost heat seal layer.

2. The cellulose structure of claim 1, wherein the cellulose sheet substrate has a maximum transmittance (%T) of 4.0% or less in the range of 300-700 nm.

3. The cellulosic structure of claim 1 or claim 2, wherein the cellulosic board substrate has a basis weight of 180 to 300 lbs / 3000 ft 2 within the range.

4. A cellulosic structure according to any one of the preceding claims, wherein the oxygen barrier resin layer comprises polyvinyl alcohol (PVOH).

5. A cellulosic structure according to any one of the preceding claims, wherein the oxygen barrier resin layer comprises ethylene vinyl alcohol (EVOH).

6. The cellulosic structure of any one of the preceding claims, wherein the oxygen barrier resin layer comprises at least one of nylon and thermoplastic starch.

7. The cellulosic structure of any one of the preceding claims, wherein the metal oxide coated polymer barrier film comprises at least one of aluminum oxide and silicon oxide.

8. The cellulosic structure of any one of the preceding claims, wherein the metal oxide coated polymer barrier film comprises at least one of a polyester or a polyolefin.

9. The cellulosic structure of any one of the preceding claims, wherein the outermost heat seal layer comprises at least one of low density polyethylene and ethylene methyl acrylate (EMA).

10. The cellulosic structure of any one of the preceding claims, wherein the oxygen barrier resin layer is located between the first side of the cellulosic sheet substrate and the metal oxide coated polymer barrier film.

11. The cellulose structure of any one of claims 1-9, wherein the metal oxide coated polymer barrier film is between the first side of the cellulose sheet substrate and the oxygen barrier resin layer.

12. A cellulosic structure according to any one of the preceding claims, wherein the cellulosic structure has a cellulose content of at least 80% by weight.

13. The cellulosic structure of any one of the preceding claims, wherein the cellulosic structure has an oxygen transmission rate of less than 1 cc / m2 / day at 1 atm after folding to 90 degrees.

14. The cellulosic structure of any one of the preceding claims, wherein the cellulosic structure has an oxygen transmission rate of less than 1 cc / m2 / day at 1 atm after folding to 180 degrees.

15. The cellulosic structure of any one of the preceding claims, wherein the cellulosic structure has a water vapor transmission rate of less than 1 g / m2 / day after folding to 90 degrees.

16. The cellulosic structure according to any one of the preceding claims, wherein the water vapor transmission rate of the cellulosic structure after folding to 180 degrees is less than 1 g / m2 / day.

17. A method for making a cellulose container, the method comprising: The cellulosic structure of any of the preceding claims is folded to form the cellulosic container.

18. A cellulose container, comprising: A sidewall component having a first end and a second end, the sidewall component comprising: a cellulose sheet substrate having a first side and a second side; an outermost heat seal layer on the first side of the cellulose sheet substrate; an oxygen barrier resin layer between the first side of the cellulose sheet substrate and the outermost heat seal layer; and a metal oxide coated polymer barrier film between the first side of the cellulose sheet substrate and the outermost heat seal layer; a bottom member surrounding the first end of the side wall member; and A cover member surrounds the second end of the side wall member.

19. A method for making a cellulose structure, the method comprising: extruding an oxygen barrier resin layer onto a first side of a cellulose sheet substrate; placing a metal oxide coated polymer barrier film on the extruded oxygen barrier resin layer; as well as A heat seal layer is applied to the metal oxide coated polymer barrier film.

20. A method for making a cellulose structure, the method comprising: applying a layer of a liquid adhesive oxygen barrier resin to a first side of a cellulose sheet substrate; placing a metal oxide coated polymer barrier film on the liquid adhesive oxygen barrier resin layer; as well as A heat seal layer is applied to the metal oxide coated polymer barrier film.

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