Biodegradable paper barrier laminates

Abstract

The present invention provides a biodegradable paper laminate including a water-dispersible barrier to permeation.

Description

Technical Field

[0001] The present invention relates to a biodegradable paper barrier laminate for flexible packaging applications or product delivery systems such as pouches, bags, and bags-in-bags, the biodegradable paper barrier laminate comprising a biodegradable paper in combination with a biodegradable laminating layer, a water-dispersible barrier layer, and a biodegradable sealant layer, the biodegradable paper barrier laminate offering several advantages over prior art paper-based flexible packaging, and a method for producing the biodegradable paper barrier laminate. Background Art

[0002] Paper packaging is becoming increasingly popular among consumers because it is perceived as more natural, biodegradable, and recyclable. However, uncoated paper has poor barrier properties, and attempts to improve barrier properties by adding coatings often result in reduced ability of the paper to biodegrade in various environments and also reduce the packaging's recyclability in commercial paper recycling systems.

[0003] Uncoated paper packaging is often highly biodegradable in certain environments and very easily recycled in commercial paper recycling systems. However, paper without any coating or adhesive cannot easily be formed into a fully functional package. Furthermore, uncoated paper packaging can only be used to contain dry products that do not require any type of barrier to water / moisture, gases, fragrances, or grease. If the dry product is sensitive to moisture, it will quickly become damaged by moisture entering the packaging. If it is oxygen-sensitive, it will oxidize. If the product is greasy, the grease will migrate through the paper and leave unsightly stains on the exterior of the packaging. If the product contains fragrance, the fragrance will escape from the packaging and change the nature of the product's intended odor. However, if a coating is added to paper to improve barrier properties and / or make it sealable, it is desirable that the coating does not affect the overall biodegradability of the packaging under a range of most desirable environmental conditions in the event of improper disposal. Failure to degrade can have adverse environmental impacts, such as the persistence of microplastics in seawater. Furthermore, great care must be taken to avoid adversely affecting the packaging's recyclability in commercial paper recycling systems.

[0004] A common approach to addressing the poor barrier properties of paper and making it sealable is to add a polyethylene-based or ethylene copolymer-based or other non-biodegradable polymer coating to the surface of the paper by coating, printing, or laminating. However, if this polyethylene coating is too thick, it will adversely affect the recyclability of the paper laminate in a typical commercial paper recycling system. There are many examples where polyethylene coatings have caused problems in the paper recycling process, especially where thicker coatings are used to enhance seal strength and / or enhance barrier properties. Examples of such problems are, but are not limited to: i) coatings that clog repulping tanks and filters in the system; ii) coatings that remain tightly attached to the paper fibers and prevent a high percentage of the paper fibers from being released into the water of the repulping system; iii) coatings that end up incorporated into the recycled paper and adversely affect the appearance or properties of the resulting recycled paper.

[0005] If this type of polyethylene coating is made very thin, it can be peeled off and sent to a landfill or burned to provide fuel to the factory, thereby leaving paper fibers to collect and be recycled into the paper, then the overall structure can be considered to be recyclable in the paper recycling stream. However, this type of structure still has some disadvantages, because if it is improperly abandoned in the environment, the paper will biodegrade, but the polyethylene coating cannot. This will instead form a lasting microplastic that has a negative impact on the environment, becoming a non-nutritional food source for some animals. In addition, many consumers notice the appearance of the glossy polyethylene layer on the inner surface of the paper laminate and react negatively to it. The polyethylene coating will also have a negative impact on the ability of the packaging to be composted via industrial or home composting, unless the consumer can easily remove the polyethylene coating before composting.

[0006] If instead a biodegradable material is used to replace polyethylene, it is well known that biodegradable materials have poor barrier properties to moisture. Such biodegradable coatings must be very thick, which causes problems in the paper recycling process.

[0007] Therefore, there is an unmet need for paper laminates for flexible packaging applications that have a moisture barrier and sealant layer that have reduced environmental impact in environments such as soil and aquatic environments and in composting situations, and that also enable increased recycling efficiency in industrial paper repulping systems. Summary of the Invention

[0008] The present invention provides a biodegradable paper barrier laminate that, in embodiments, is compatible with home or industrial composting facilities, is biodegradable when improperly disposed of in the environment, and is recyclable in industrial paper recycling facilities. The laminate is made from: a biodegradable paper layer having an outer surface and an inner surface; a first biodegradable polymer layer having an outer surface and an inner surface, the outer surface being disposed on the inner surface of the paper layer; a water-dispersible barrier layer having an outer surface and an inner surface, the outer surface being disposed on the inner surface of the biodegradable polymer layer; and a second biodegradable polymer layer having an outer surface and an inner surface, the outer surface being disposed on the inner surface of the water-dispersible barrier layer.

[0009] The present invention provides a biodegradable paper barrier laminate that is compatible with home or industrial composting facilities, is biodegradable when improperly disposed of in the environment, and is recyclable in industrial paper recycling facilities. The laminate is made from: a biodegradable paper layer having an outer surface and an inner surface; a first biodegradable polymer layer having an outer surface and an inner surface, the outer surface being disposed on the inner surface of the paper layer; a water-dispersible barrier layer having an outer surface and an inner surface, the outer surface being disposed on the inner surface of the biodegradable polymer layer; a biodegradable adhesive layer having an outer surface and an inner surface, the outer surface being disposed on the inner surface of the water-dispersible barrier layer; and a second biodegradable polymer layer having an outer surface and an inner surface, the outer surface being disposed on the inner surface of the water-dispersible barrier layer.

[0010] A method for preparing a biodegradable paper barrier laminate comprises the following steps: applying a first aqueous system of a water-based biodegradable polymer composition to the surface of a removable flat carrier such as a PET film or a steel tape; removing water from the first aqueous system of the water-based biodegradable polymer composition to obtain a first biodegradable polymer layer; applying an aqueous dispersion of hydrophilic nanoplatelets to the outer surface of the first biodegradable polymer layer; removing water from the aqueous dispersion of hydrophilic nanoplatelets to obtain a water-dispersible barrier layer; applying a second aqueous system of the water-based biodegradable polymer composition to the surface of a biodegradable paper layer, which is preferably mechanically glazed and / or sized or is kraft paper or glassine paper to avoid moisture swelling; combining the outer surface of the water-dispersible barrier layer with the second aqueous system of the water-based biodegradable polymer composition; removing water from the second aqueous solution of the water-based biodegradable polymer composition to obtain a second biodegradable polymer layer; and removing the flat carrier from the resulting biodegradable paper barrier laminate. In the case where the aqueous biodegradable polymer composition is not soluble in water, an additional step may be taken to heat the biodegradable polymer composition to melt it and allow it to form a continuous biodegradable polymer layer. If the biodegradable polymer composition is water soluble, this heating step is not required.

[0011] A method for making a biodegradable paper barrier laminate comprises the following steps: applying a first aqueous system of an aqueous biodegradable polymer composition to a surface of a removable flat carrier such as a PET film or a steel tape; removing water from the first aqueous system of the aqueous biodegradable polymer composition to obtain a first biodegradable polymer layer; applying heat to the first biodegradable polymer layer to form a continuous first biodegradable polymer layer; applying an aqueous dispersion of hydrophilic nanosheets to an outer surface of the first biodegradable polymer layer; removing water from the aqueous dispersion of hydrophilic nanosheets to obtain a water-dispersible barrier layer; applying a second aqueous system of the aqueous polymer composition to an inner surface of a biodegradable paper layer; bonding the outer surface of the water-dispersible barrier layer to the second aqueous system of the aqueous polymer composition; removing water from the second aqueous system of the aqueous biodegradable polymer composition to obtain a second biodegradable polymer layer; and removing the flat carrier from the resulting recyclable paper barrier laminate.

[0012] A method for preparing a biodegradable paper barrier laminate comprises the following steps: applying a first aqueous system of a water-based biodegradable polymer composition to the inner surface of a biodegradable paper layer, the paper layer preferably being mechanically glazed and / or sized or being kraft or glassine to prevent moisture swelling; removing water from the first aqueous system of the water-based biodegradable polymer composition to obtain a first biodegradable polymer layer; applying an aqueous dispersion of hydrophilic nanoplatelets to the inner surface of the first biodegradable polymer layer; removing water from the aqueous dispersion of hydrophilic nanoplatelets to obtain a water-dispersible barrier layer; applying a second aqueous system of the water-based biodegradable polymer composition to the inner surface of the water-dispersible barrier layer; removing water from the second aqueous system of the water-based biodegradable polymer composition to obtain a second biodegradable polymer layer. In the case where the water-based biodegradable polymer composition is insoluble in water, an additional step of heating the biodegradable polymer composition to melt it and allow it to form a continuous biodegradable polymer layer may be employed; however, if the biodegradable polymer composition is water-soluble, this heating step is not required.

[0013] A method for preparing a biodegradable paper barrier laminate comprises the following steps: applying a first aqueous system of an aqueous biodegradable polymer composition to the inner surface of a biodegradable paper layer, the paper layer preferably being mechanically glazed and / or sized or being kraft paper or glassine paper to avoid moisture swelling; removing water from the first aqueous system of the aqueous biodegradable polymer composition to obtain a first biodegradable polymer layer; in the case where the aqueous biodegradable polymer composition is insoluble in water, an additional step may be taken to heat the biodegradable polymer composition to melt it and allow it to form a continuous biodegradable polymer layer, and if the biodegradable polymer composition is water-soluble, this heating step is not required; applying an aqueous dispersion of hydrophilic nanoplatelets to the inner surface of the first biodegradable polymer layer; removing water from the aqueous dispersion of hydrophilic nanoplatelets to obtain a water-dispersible barrier layer; melting a second biodegradable polymer composition in an extruder; hot extruding the molten second biodegradable polymer composition onto the surface of the water-dispersible barrier layer; and cooling the second biodegradable polymer composition to form a second biodegradable polymer layer.

[0014] A method for preparing a biodegradable paper barrier laminate comprises the following steps: applying a first aqueous system of a waterborne biodegradable polymer composition to the inner surface of a biodegradable paper layer, the paper layer preferably being mechanically glazed and / or sized or being kraft paper or glassine paper to prevent moisture swelling; removing water from the first aqueous system of the waterborne biodegradable polymer composition to obtain a first biodegradable polymer layer; in the case where the waterborne biodegradable polymer composition is not soluble in water, an additional step may be taken to heat the biodegradable polymer composition to melt it and allow it to form a continuous biodegradable polymer layer. The invention relates to a method for preparing a water-dispersible barrier layer comprising: applying an aqueous dispersion of hydrophilic nanosheets to the inner surface of the first biodegradable polymer layer; applying the aqueous dispersion of hydrophilic nanosheets to the inner surface of the first biodegradable polymer layer; removing water from the aqueous dispersion of hydrophilic nanosheets to obtain a water-dispersible barrier layer; applying a biodegradable adhesive to the inner surface of the water-dispersible barrier layer; separately obtaining a film made of the biodegradable polymer composition by various methods including solution casting, hot cast film extrusion and hot blown film extrusion; and applying the film made of the biodegradable polymer composition to the surface of the biodegradable adhesive. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A cross section of a biodegradable paper layer 10 is shown.

[0016] Figure 2 A cross section of a biodegradable polymer layer 20 coated on a biodegradable paper layer 10 is shown.

[0017] Figure 3 A cross section of a water-dispersible nanoplatelet layer 30 coated on a biodegradable polymer layer 20 , which is coated on a biodegradable paper layer 10 , is shown.

[0018] Figure 4 A cross-section of one embodiment of a biodegradable paper barrier laminate according to the present invention is shown, the laminate comprising a biodegradable polymer layer 40 coated on a water-dispersible nanoplatelet layer 30, which is coated on a biodegradable polymer layer 20, which is coated on a biodegradable paper layer 10.

[0019] Figure 5 A schematic diagram showing a method of preparing a biodegradable paper barrier laminate according to the present invention is shown.

[0020] Figure 6 Shown are cross-sectional images of one embodiment of a biodegradable paper barrier laminate obtained via scanning electron microscopy in conjunction with energy dispersive spectroscopy.

[0021] Figure 7Schematic diagram showing the application of a biodegradable paper barrier laminate. DETAILED DESCRIPTION

[0022] A biodegradable paper barrier laminate that offers several advantages over prior art paper barrier laminates, as well as several methods for making the biodegradable paper barrier laminate, are described.

[0023] As used herein, the term "water vapor transmission rate" or "WVTR" refers to the rate at which water vapor permeates through a film when measured according to the Water Vapor Permeation Test Method set forth in the Test Methods section.

[0024] As used herein, the term "dissolution time" refers to the time required for a water-soluble film, such as a film made from polymerized vinyl alcohol, to dissolve when measured according to the Dissolution Test Method set forth in the Test Methods section.

[0025] As used herein, the term "water-dispersible" means breaking into small fragments less than 1 mm in water. These fragments may, but need not, be stably suspended in water.

[0026] As used herein, the term "copolymer" refers to a polymer formed from two or more types of monomer repeat units. As used herein, the term "copolymer" also encompasses terpolymers, such as terpolymers having a distribution of vinyl alcohol monomer units, vinyl acetate monomer units, and possibly butene glycol monomer units; however, if the copolymer is substantially completely hydrolyzed, vinyl acetate monomer units may be substantially absent.

[0027] As used herein, the term "degree of hydrolysis" refers to the mole percentage of vinyl acetate units that are converted to vinyl alcohol units when polymerized vinyl alcohol is hydrolyzed.

[0028] As used herein, when the term "about" modifies a particular value, the term refers to a range equal to the particular value plus or minus twenty percent (+ / - 20%). For any of the embodiments disclosed herein, in various alternative embodiments, any disclosure of a particular value may also be understood to be a disclosed range approximately equal to that particular value (i.e., + / - 20%).

[0029] As used herein, when the term "about" modifies a particular value, the term refers to a range equal to the particular value plus or minus fifteen percent (±15%). For any of the embodiments disclosed herein, in various alternative embodiments, any disclosure of a particular value may also be understood to be a disclosed range approximately equal to that particular value (i.e., ±15%).

[0030] As used herein, when the term "substantially" modifies a particular value, the term refers to a range equal to the particular value plus or minus ten percent (±10%). For any of the embodiments disclosed herein, in various alternative embodiments, any disclosure of a particular value may also be understood to be a disclosed range approximately equal to that particular value (i.e., ±10%).

[0031] As used herein, when the term "approximately" modifies a particular value, the term refers to a range equal to the particular value plus or minus five percent (±5%). For any of the embodiments disclosed herein, any disclosure of a particular value may also be understood to refer to a disclosed range approximately equal to that particular value (i.e., ±5%) in various alternative embodiments.

[0032] Figure 1 There is shown a cross section of the biodegradable paper layer 10. The biodegradable paper layer 10 has a first surface 12 and a second surface 14 opposite the first surface 12, a thickness 116 between the surfaces 12 and 14, and a grammage obtained from the thickness 116 and the paper density.

[0033] The biodegradable paper layer 10 may have a grammage of about 20 g / m 2 About 200g / m 2 , preferably about 40g / m 2 About 120g / m 2 , more preferably about 50g / m 2 About 100g / m 2 , and more preferably about 60 g / m 2 Up to 85g / m 2 within the range.

[0034] Figure 2 A cross-section of a biodegradable polymeric barrier layer 20 is shown, the barrier layer having a first surface 22 and a second surface 24 opposite the first surface 22 and a thickness 216 between the first surface 22 and the second surface 24, the barrier layer being applied to substantially cover at least one of the first surface 12 or the second surface 14 of the biodegradable paper layer 10.

[0035] The thickness 216 of the biodegradable polymer layer 20 may range from about 1 μm to about 120 μm, preferably from about 1 μm to about 25 μm, more preferably from about 1 μm to about 10 μm, and even more preferably from about 1 μm to about 5 μm.

[0036] The biodegradable polymer layer 20 comprises at least one biodegradable polymer. Depending on the application, the biodegradable polymer can be water-soluble or water-insoluble. If water-soluble, the biodegradable polymer can be selected from available options to dissolve in water at 23°C within seconds, minutes, or hours. Biodegradable polymers that require more than 24 hours to dissolve in water at 23°C are not considered water-soluble.

[0037] Figure 3 A cross-section of a water-dispersible barrier layer 30 is shown, the barrier layer having a first surface 32 and a second surface 34 opposite the first surface 32 and a thickness 316 between the first surface 32 and the second surface 34, the barrier layer being applied to substantially cover at least one of the first surface 22 or the second surface 24 of the biodegradable polymer layer 20.

[0038] The thickness of the water-dispersible barrier layer 30 ranges from about 0.1 μm to about 20 μm, preferably from about 0.1 μm to about 10 μm, more preferably from about 0.1 μm to about 5 μm.

[0039] The water-dispersible barrier layer 30 comprises 90% to 100% nanosheets, more preferably 96% to 100% nanosheets, and even more preferably 99% to 100% nanosheets, such as sodium cloisite or sodium hectorite, and is substantially free of other materials, such as binders, dispersants, surfactants, or polymers, in the interstices between the assembled nanosheets. This means that the cohesion of the nanosheet layer is provided solely by the interactions between the nanosheets and the adhesion to the biodegradable polymer layer. The absence of binders (interstitial materials) in the nanosheet layer maximizes the barrier properties of the nanosheet layer to water permeation while maintaining the dispersibility of the hydrophilic nanosheet layer in water once the top / bottom biodegradable polymer layer is removed by dissolution and / or decomposition in water if they are sent for paper recycling or if they are improperly disposed of in an environment where water is present. Nanosheets that require more than 24 hours to disperse in water at a temperature of 23°C are not considered water-dispersible.

[0040] Nanosheets are flaky nanoparticles characterized by a high aspect ratio between diameter and orthogonal height. The high aspect ratio enables the formation of a "brick wall" in which the nanosheets are placed parallel to the surface of the underlying biodegradable polymer layer, overlapping and stacked on top of each other, thereby significantly reducing the migration of molecules (whether gas or liquid) through the nanosheet layer. The higher the aspect ratio, the higher the barrier performance that can be achieved. Typical aspect ratios for nanosheets exfoliated from montmorillonite are about 100 or greater (Cadène et al., JCIS 285(2):719-30, June 2005).

[0041] The water-dispersible barrier layer 30 according to the present invention can be optically opaque, preferably translucent, and even more preferably transparent, depending on the nanosheet material (exfoliation level, impurity level) and the nanosheet application method.

[0042] Preferably, the water-dispersible barrier layer 30 is slightly flexible. When converting paper structures through production lines for printing, sheeting, slitting, rewinding, and other typical converting operations, or when manufacturing articles such as bags that include a biodegradable paper barrier laminate, the entire biodegradable paper barrier laminate structure is typically folded, bent, and sometimes slightly stretched. This can cause some of the barrier layer to break, potentially reducing its performance as a barrier layer. Therefore, it is preferred that the barrier layer 30 be slightly flexible and stretchable without breaking as the rest of the structure stretches. Preferably, the barrier layer 30 can stretch by at least 1%, at least 2%, or at least 5% as the underlying paper and biodegradable polymer layers stretch. In some cases, it may be desirable for the barrier layer to stretch by as much as 10% or even as much as 20% without breaking. In one embodiment, this is achieved by dividing the water-dispersible barrier layer into multiple different water-dispersible barrier sublayers separated by multiple different water-soluble polymer sublayers.

[0043] Figure 4 A cross-section of a biodegradable paper barrier laminate 150 is shown that includes a biodegradable paper layer 10 having a first surface 12, a second surface 14 opposite the first surface 12, and a thickness 116 between the first and second surfaces 12, 14. Attached to the biodegradable paper layer is a first biodegradable polymer layer 20 having a first surface 22, a second surface 24 opposite the first surface 22, and a thickness 216 between the first and second surfaces 22, and substantially covering at least one of the first surface 12 or the second surface 14 of the paper layer 10. Attached to the first biodegradable polymer layer is a water-dispersible barrier layer 30 having a first surface 32, a second surface 34 opposite the first surface 32, and a thickness 316 between the first and second surfaces 32, and substantially covering the second surface 24 of the biodegradable polymer layer 20. Attached to the water-dispersible barrier layer is a second biodegradable polymer layer having a first surface 42 and a second surface 44 opposite the first surface 42, and a thickness 416 between the first surface 42 and the second surface 44, and substantially covering the surface 32 of the water-dispersible barrier layer 30. Adhesion between the layers is provided by the interaction between the biodegradable polymer and the hydrophilic nanosheets.

[0044] The thickness of the biodegradable polymer layer 40 between the first surface 42 and the second surface 44 may be in the range of about 1 μm to about 1000 μm, preferably about 1 μm to about 200 μm, more preferably about 1 μm to about 40 μm.

[0045] Biodegradable polymer layer 40 comprises at least one biodegradable polymer. Depending on the application, the biodegradable polymer can be selected to be water-soluble or water-insoluble. If the application requires a water-soluble polymer, one can select from available water-soluble polymer options that dissolve in water at 23°C within seconds, minutes, or hours. Polymers that require more than 24 hours to dissolve in water at 23°C are not considered water-soluble.

[0046] Each layer according to the present invention is distinct and separate from one another. By distinct, it is meant that the barrier layer 30 between the biodegradable polymer layers 20 and 40 comprises essentially only nanosheets, and that the boundary between the barrier layer 30 and the surrounding biodegradable polymer layers 20 and 40 is distinguished by a large compositional change over a small distance, thereby forming a sharp boundary that is easily visible using microscopy techniques known in the art. The boundary layer (i.e., the intermediate layer of intermediate composition between the water-dispersible nanosheet layer and the adjacent biodegradable polymer layer) is no more than 2 μm thick, as seen using microscopy techniques known in the art.

[0047] Figure 6 A cross-sectional image of a biodegradable paper barrier laminate obtained via scanning electron microscopy (SEM) is shown. The biodegradable paper barrier laminate consists of a biodegradable paper layer coated with a first water-soluble biodegradable polyvinyl alcohol layer, a water-dispersible Crosette barrier layer, and a second water-soluble biodegradable polyvinyl alcohol layer. The second water-soluble biodegradable polyvinyl alcohol layer is less visible than the first water-soluble biodegradable polyvinyl alcohol layer because it is much thinner. EDX color coding helps emphasize the chemical differences between the layers.

[0048] When the biodegradable paper barrier laminate according to the present invention is immersed in water (e.g., in a paper recycling process if the waste is managed, or in an aqueous environment if the waste is discarded inappropriately), in a water treatment plant (if recycled) or in an aqueous environment (river, sea) (if discarded inappropriately) or in a composting system (if the packaging is composted), the biodegradable polymer layer will dissolve and / or decompose and its components will be consumed by bacteria. Immersed in water without a surrounding and supporting water-soluble polymer layer, the water-dispersible barrier layer will break down and the nanoplatelets will be consumed as organic carbon in the case of graphene or graphene oxide, or dispersed as mineral-rich soil in the case of natural clay or mica, regardless of whether the waste is preferably managed or discarded inappropriately. This leaves the paper layer completely uncoated and easily biodegradable or recyclable, since the paper layer is selected from biodegradable and recyclable grades.

[0049] All embodiments of the present invention are compatible with current paper recycling systems, i.e., they must readily disintegrate when stirred into large quantities of warm water. For current typical industrial repulping facilities, paper packaging must be broken down within 5 to 20 minutes of immersion in warm water under constant vigorous agitation.

[0050] If improperly discarded in the environment, the packaging must also disintegrate quickly, exposing the maximum surface area to the bacteria responsible for biodegradation and ensuring complete consumption within a reasonable timeframe. Ideally, the packaging will biodegrade within 6 to 12 months. And if the packaging is compostable, it must be completely consumed within the normal timeframe expected for compostable packaging.

[0051] The biodegradable paper barrier laminate according to the present invention may include a printed area. Printing may be achieved using standard printing techniques such as flexographic printing, gravure printing, or inkjet printing. The biodegradable paper barrier laminate according to the present invention may include a surface coating for cosmetic purposes, such as protection from accidental water exposure or for matte / high gloss effects.

[0052] Paper

[0053] Cellulosic fibers used to make paper can be derived from softwoods, hardwoods, and non-tree fibers, which generally have shorter fibers and include bamboo, grasses, hemp, kenaf, flax, corn husks, cotton stalks, coffee grounds, sugarcane bagasse, rice straw, wheat straw, algae, abaca, sabia grass, esparto grass, milkweed fibers, pineapple leaf fibers, wood fibers, pulp fibers, and the like.

[0054] The paper used to prepare the biodegradable paper barrier laminates of the present disclosure is biodegradable, does not leave any persistent materials in the environment, and is also preferably recyclable in typical paper recycling streams. In reality, paper is not made of only 100% cellulose fibers, but also contains polymer binders, mineral adhesives, brighteners, surfactants, and other additives. These other ingredients must be appropriately selected to ensure that (a) the paper will biodegrade if improperly disposed of in the environment, or (b) the paper will break down in a repulping unit at a paper recycling facility and release a maximum amount of cellulose fibers for use in making recycled paper.

[0055] The effectiveness of the recycling process can be determined via the recyclable percentage. The recyclable percentage of the paper barrier laminate of the present disclosure is determined by test method PTS-RH:021 / 97 (draft October 2019), Class II, performed by the German Institute for Paper Technology (Papiertechnische Stiftung, located at Pirnaer Strasse 37, 01809 Heidenau, Germany). Together with the recyclable percentage, the total reject percentage is also determined by PTS-RH:021 / 97 (draft October 2019), Class II. The total reject percentage of the packaging material of the present disclosure may be 40% or less, 30% or less, or 10% or less, specifically including all values ​​within these ranges and any ranges therein or formed therefrom. For example, the total reject percentage of the packaging material of the present disclosure may be from about 0.5% to about 40%, from about 0.5% to about 30%, or from about 0.5% to about 10%, specifically including all values ​​within these ranges and any ranges therein or formed therefrom.

[0056] It is believed that the percentage of non-recyclable material does not necessarily have a 1:1 correlation with the total rejection percentage. For example, dissolvable adhesives and / or coatings are designed to dissolve during the recycling process. In theory, these adhesives may not affect the total rejection percentage; however, they will contribute to the weight percentage of non-recyclable material.

[0057] Category II of test method PTS-RH:021 / 97 (draft October 2019) also includes a visual component. Trained screeners inspect one or more sheets of recycled packaging material for visual defects. If the number of visual defects is excessive, the packaging material is rejected. If the number of visual defects is acceptable, the packaging material is approved for additional processing according to Category II of test method PTS-RH:021 / 97 (draft October 2019). The paper barrier laminates of the present disclosure can produce an acceptable level of visual defects during this step of the process.

[0058] The paper barrier laminates of the present disclosure can produce the aforementioned recyclable percentages and pass the visual screening method. Therefore, when subjected to Class II of test method PTS-RH: 021 / 97 (draft October 2019), the paper barrier laminates of the present disclosure can obtain an overall score or final result of "pass".

[0059] It is also worth noting that there are alternative methods for determining the percent recyclability of the paper barrier laminates of the present disclosure. A test method known as the Repulpability Test Method, performed by Western Michigan University, can provide a percent yield of recyclable material. While there are minor differences between the Repulpability Test Method performed by Western Michigan University and Category II of Test Method PTS-RH:021 / 97 (October 2019 Draft), it is believed that the percent yield of the Repulpability Test Method will be similar to the percent recyclability provided by Category II of Method PTS-RH:021 / 97 (October 2019 Draft).

[0060] For commercial reasons, it is also important that a paper recycling facility can obtain at least 50% by weight of cellulose fibers from an incoming batch of waste paper. To this end, it is preferred that the paper layer itself contains at least between 50% and 100% by weight of cellulose fibers, more preferably between 65% and 90% by weight of cellulose fibers, and most preferably between 75% and 95% by weight of cellulose fibers.

[0061] It is contemplated that the biodegradable paper of the present disclosure, while being recyclable, may itself contain recycled material. For example, the biodegradable paper of the present invention may contain greater than 10% by weight, preferably greater than 20% by weight, and more preferably greater than 30% by weight of recycled material, with all values ​​within these ranges and any ranges derived therefrom being specifically recited. The biodegradable paper may contain between 0% and 100% virgin paper or recycled paper, or a mixture thereof.

[0062] The presence of recycled materials can be detected by visual inspection of the packaging. Manufacturers often promote the use of recycled materials to demonstrate their eco-friendly image. To this end, they may use a logo, such as a leaf, and text indicating that recycled materials are used in the packaging. Manufacturers may also specify the percentage of recycled materials used, such as greater than 50%, greater than 70%, etc.

[0063] Visual inspection can simply involve using the human eye to search for signs of the use of recycled materials. Additionally or alternatively, visual inspection can include microscopy, such as optical microscopy, scanning electron microscopy, or other suitable methods known in the art. For example, packaging material containing recycled paper fibers may appear different under a microscope due to the presence of a wider range of natural fibers compared to packaging material containing 100% virgin fibers.

[0064] It is preferred that the paper be as flat as possible on at least one side, which is then coated with an aqueous polymer system to form a contiguous aqueous biodegradable polymer layer. Paper can be flattened by "sizing," which in the industry means coating it with an aqueous polymer suspension containing various inorganic fillers (such as clay, calcium carbonate, and / or titanium dioxide), followed by drying the suspension and calendering the paper to achieve a flatter surface than before sizing, as the inorganic fillers and binder dehydrate to fill the porous, rough surface of the paper. Alternatively, the paper can be mechanically glazed during the papermaking process by a mechanical ironing / pressing step, which sometimes involves heating—in this case, squeezing the paper fibers together and flattening them to densify the paper surface and remove porosity. In some cases, sizing and mechanical glazing are combined to achieve an even flatter, more polished surface during the papermaking process, followed by coating with an aqueous biodegradable polymer layer. In other cases, kraft or glassine or tracing paper may be used which is already naturally very flat - such papers are made by a process which densifies the paper structure throughout its thickness during manufacture and require no further sizing or varnishing.

[0065] Examples of papers suitable for preparing biodegradable paper barrier laminates include: Leine Paper (weight 85g / m 2 ), glossy paper with "OK HomeCompost" certification; NiklaSelect V natural linen paper (99 g / m 2 ), paper with sizing on only one side; PackPro7.0 paper (65 g / m 2 ), double-sided sized paper; obtained from (Solna, Sweden) Axello paper (including Axello tough white paper, 80g / m 2 ), which is designed to be tougher than many other papers and therefore may have some advantages in the distribution chain; SCG Glassine paper (58 g / m 2 ).

[0066] As shown in Table 1 below, these papers have passed the paper recycling programs of Western Michigan University in the United States and the PTS Institute in Germany. These papers also passed the OECD 301B biodegradation screening test, undergoing at least 60% biodegradation within 28 days.

[0067] Table 1

[0068]

[0069] In order to withstand the stresses of the high speed manufacturing process (where the product is placed in a package made from the disclosed laminate) as well as the stresses of transportation, the paper layer must be strong and resilient enough. There are countless ways to specify a paper layer. The metrics discussed below are MD tensile strength in kN / m, CD tensile strength in kN / m, MD stretch in percent, CD stretch in percent, MD burst strength in kPa, thickness in μm, MD tensile energy absorption in J / g, CD tensile energy absorption in J / g, and g / m 2 While all of the metrics may be used in combination to select the appropriate paper in the present invention, some metrics alone or in combination with other metrics may also suffice.

[0070] Where a very strong paper is required to maintain the physical integrity of the water dispersible barrier layer, it is preferred to use a paper obtained from of For example, Table 2 below shows the of Properties of a tough white paper grade or Advantage Smooth White Strong paper from Mondi.

[0071] Table 2

[0072]

[0073] Water-insoluble biodegradable water-based polymer

[0074] In some embodiments, it is preferred that at least one of the biodegradable polymer layers is made of a water-insoluble polymer. These materials are often referred to as "bioplastics" and biodegradable polymers.

[0075] In one case, biodegradable aliphatic polyesters and copolyesters can be prepared by large-scale bacterial fermentation. Collectively referred to as polyhydroxyalkanoates, also referred to as "PHAs," these polymers can be harvested in fermentation plants by plants or bacteria fed with specific substrates, such as glucose. In many cases, the structure or mechanical properties of PHAs can be customized to meet the specifications of the desired application. PHAs and their copolymers can be degraded aerobically and anaerobically. This makes them particularly suitable for composting or rapid and complete degradation in the environment. Such bioplastics are typically suspended in aqueous emulsions and can be dried into films on various substrates, although they can also be extruded into films and coatings.

[0076] PHA is available as a copolymer, which is commercially available as a film grade for extrusion and blow molding from ShenZhen Ecomann Biotechnology Co., Danimer Scientific, Inc., which produces poly(β-hydroxyalkanoate), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (NODAX™), or Kaneka, which produces poly(3-hydroxybutyrate-co-3-hydroxyhexanoate). Non-limiting examples of PHA copolymers include those described in U.S. Patent No. 5,498,692. Other PHA copolymers can be synthesized by methods known to those skilled in the art, such as by microorganisms, ring-opening polymerization of β-lactones, dehydration polycondensation of hydroxyalkanoic acids, and dealcoholization polycondensation of hydroxyalkanoic acid alkyl ethers, as described in Volova, "PolyhydroxyAlkanoates Plastic Materials of the 21 Century: Production, Properties, and Application, Nova Science Publishers, Inc., (2004), which is incorporated herein by reference.

[0077] Other possible biodegradable water-insoluble polymers may include biodegradable thermoplastic materials selected from the group consisting of aliphatic aromatic polyesters (e.g., It is a blend of polybutylene adipate terephthalate (PBAT), polylactic acid (PLA) and polybutylene adipate terephthalate; and thermoplastic starch (e.g., MATER-BI from Novamont or MATER-B1 from Plantic / Kuraray). ), polybutylene succinate (PBS) and copolymers thereof (e.g., available from ShoWa High polymer Co. or polybutylene succinate adipate (PBSA) from Mitsubishi Chemicals (Tokyo, Japan), and mixtures thereof.

[0078] Water-soluble biodegradable water-based polymer

[0079] In some embodiments, it is preferred that at least one of the biodegradable polymer layers is made of a water-soluble polymer. Preferred polymers, copolymers or derivatives thereof suitable for use as the water-soluble polymer layer are selected from polyvinyl alcohol (PVOH), copolymers of polyvinyl alcohol (such as butene glycol-vinyl alcohol copolymer (BVOH)), copolymers or derivatives of the water-soluble polymer layer, which are produced by copolymerization of butene glycol with vinyl acetate, followed by hydrolysis of vinyl acetate, suitable butene glycol monomers are selected from 3,4-diol-1-butene, 3,4-diacyloxy-1-butene, 3-acyloxy-4-ol-1-butene, 4-acyloxy-3-ol-1-butene, etc.; polyvinyl pyrrolidone; polyalkylene oxides such as polyethylene oxide or polyethylene glycol (PEG); poly(methyl methacrylate) Acrylic acid), polyacrylic acid, polyacrylates, acrylate copolymers, maleic acid / acrylic acid copolymers; polyacrylamide; poly(2-acrylamido-2-methyl-1-propanesulfonic acid (polyAMPS); polyamides, poly-N-vinylacetamide (PNVA); polycarboxylic acids and salts; cellulose derivatives such as cellulose ethers, methylcellulose, hydroxyethylcellulose, carboxymethylcellulose; hydroxypropyl methylcellulose; natural gums such as xanthan gum and carrageenan; sodium alginate; maltodextrin, low molecular weight dextrin; polyamino acids or peptides; proteins such as casein and / or caseinates (e.g., as commercialized by Lactips).

[0080] The most preferred water-soluble biodegradable polymers are polyvinyl alcohol, polyethylene oxide, methylcellulose, and sodium alginate. For applications requiring a "plastic-free" product, the majority of the water-soluble polymer layer can be naturally derived polymers, such as sodium alginate. Preferably, the biodegradable polymer content of the water-soluble polymer layer is at least 60%.

[0081] The average molecular weight (measured by gel permeation chromatography) of the water-soluble biodegradable polymer is from about 1,000Da to about 1,000,000Da, or any integer value from about 1,000Da to about 1,000,000Da, or any range formed by any of the aforementioned values, such as from about 10,000Da to about 300,000Da, from about 20,000Da to about 150,000Da, etc. More specifically, the molecular weight of polyvinyl alcohol can be in the range of 30,000Da to 150,000Da. The molecular weight of polyethylene oxide will be in the range of 50,000Da to 400,000Da. The molecular weight of methylcellulose will be in the range of 10,000Da to 100,000Da. The molecular weight of sodium alginate will be in the range of 10,000Da to 240,000Da.

[0082] If homopolymer polyvinyl alcohol is used, the degree of hydrolysis can be from 70% to 100%, or any integer percentage value between 70% and 100%, or any range formed by any of these values, such as 80% to 100%, 85% to 100%, 90% to 100%, 95% to 100%, 98% to 100%, 99% to 100%, 85% to 99%, 90% to 99%, 95% to 99%, 98% to 99%, 80% to 98%, 85% to 98%, 90% to 98%, 95% to 98%, 80% to 95%, 85% to 95%, 90% to 95%, etc.

[0083] Biodegradable adhesives

[0084] Solution or solvent-based adhesive compositions can also be used to adhere the film to the substrate. Non-limiting examples of adhesives can include acrylics, polyvinyl acetates, polyester-polyurethane elastomers, and other common adhesive bonding layers suitable for polar materials. One commercially available example is Epotal 3702 from BASF. In some embodiments, the adhesive is a renewable adhesive, such as available from Berkshire Labels.

[0085] Optional ingredients

[0086] The biodegradable polymer layer of the water-soluble, biodegradable paper barrier laminate may contain disintegrants, plasticizers, surfactants, lubricants / release agents, fillers, bulking agents, antiblocking agents, anti-tacking agents, defoaming agents, or other functional ingredients.

[0087] Certain applications may require that the water-soluble biodegradable polymer layer contain a disintegrant to increase its dissolution rate in water. Suitable disintegrants include, but are not limited to, corn / potato starch, methylcellulose, mineral clay powder, cross-linked carboxymethylcellulose (cross-linked cellulose), crospovidone (cross-linked polyvinyl N-pyrrolidone or PVP), and sodium starch glycolate (cross-linked starch). Preferably, the water-soluble polymer layer comprises between 0.1% and 15% by weight, more preferably about 1% to about 15% by weight of a disintegrant.

[0088] In some embodiments, the water-soluble biodegradable polymer layer may include a water-soluble plasticizer. Preferably, the water-soluble plasticizer is selected from water, polyols, sugar alcohols and mixtures thereof. Suitable polyols include polyols selected from the group consisting of glycerol, diglycerol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol of up to 400Da molecular weight, neopentyl glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, polypropylene glycol, 2-methyl-1,3-propanediol, methylene glycol, trimethylolpropane, hexylene glycol, neopentyl glycol and polyether polyols, or mixtures thereof. Suitable sugar alcohols include sugar alcohols selected from the group consisting of isomalt, maltitol, sorbitol, xylitol, erythritol, ribitol, galactitol, pentaerythritol and mannitol, or mixtures thereof. In some cases, the plasticizer can be selected from the following list: ethanolamine, alkyl citrate, isosorbide, pentaerythritol, glucosamine, N-methylglucamine, or sodium cumene sulfonate. Less mobile plasticizers, such as sorbitol or polyethylene oxide, can promote the formation of a water-soluble polymer layer with greater barrier properties compared to a water-soluble polymer layer that includes a more mobile plasticizer, such as glycerol. In some cases, when it is desirable to use as many naturally derived materials as possible, the following plasticizers can also be used: vegetable oils, polysorbate, polydimethylsiloxane, mineral oil, paraffin, C1-C3 alcohols, dimethyl sulfoxide, N,N-dimethylacetamide, sucrose, corn syrup, fructose, dioctyl sodium sulfosuccinate, triethyl citrate, tributyl citrate, 1,2-propylene glycol, monoacetate, diacetate, or triacetate of glycerol, natural gums, citrate salts, and mixtures thereof. More preferably, the water-soluble plasticizer is selected from glycerol, 1,2-propylene glycol, 20-dipropylene glycol, 2-methyl-1,3-propanediol, trimethylolpropane, triethylene glycol, polyethylene glycol, sorbitol, or mixtures thereof, and most preferably selected from glycerol, sorbitol, trimethylolpropane, dipropylene glycol, and mixtures thereof. Preferably, the water-soluble polymer layer comprises between 5% and 50% by weight, preferably between 10% and 40% by weight, and even more preferably from about 12% to about 30% by weight of the plasticizer.

[0089] In some embodiments, the biodegradable polymer layer comprises a surfactant. Suitable surfactant can belong to nonionic, cationic, anionic or zwitterionic categories. Suitable surfactant is but not limited to poloxamer (polyoxyethylene polyoxypropylene glycol), alcohol ethoxylate, alkylphenol ethoxylate, tertiary acetylenic glycol and alkanolamide (nonionic), polyoxyethylene amine, quaternary ammonium salt and polyoxyethylene quaternary amine (cationic) and amine oxide, N-alkyl betaine and sulfobetaine (zwitterionic). Other suitable surfactants are acylated fatty acid esters of sodium sulfosuccinate, glycerol and propylene glycol, fatty acid lactyl fat, sodium alkyl sulfate, polysorbate 20, polysorbate 60, polysorbate 65, polysorbate 80, lecithin, glycerol and propylene glycol and the acetylated fatty acid esters of 5 kinds of fatty acids and their combination. Preferably, the water-soluble polymer layer comprises a surfactant between 0.1 % by weight and 2.5 % by weight, more preferably from about 1 % by weight to about 2 % by weight.

[0090] In some embodiments, the biodegradable polymer layer according to the present invention comprises a lubricant / release agent. Suitable lubricants / release agents include, but are not limited to, fatty acids and their salts, fatty alcohols, fatty acid esters, fatty amines, fatty amine acetates, and fatty amides. Preferred lubricants / release agents are fatty acids, fatty acid salts, fatty amine acetates, and mixtures thereof. Preferably, the water-soluble polymer layer comprises from 0.02% to 1.5% by weight, preferably from about 0.1% to about 1% by weight, of the lubricant / release agent.

[0091] In some embodiments, biodegradable polymer layer comprises filler, extender, antiblocking agent, release agent according to the present invention.Suitable filler, extender, antiblocking agent, release agent are but not limited to starch, modified starch, cross-linked polyvinyl pyrrolidone, cross-linked cellulose, microcrystalline cellulose, silicon dioxide, metal oxide, calcium carbonate, talc and mica.Preferably, biodegradable polymer layer comprises filler, extender, antiblocking agent, release agent of 0.1 % by weight to 25 % by weight, more preferably about 1 % by weight to about 15 % by weight.In the absence of starch, biodegradable polymer layer preferably comprises filler, extender, antiblocking agent of 1 % by weight to 5 % by weight.

[0092] In some embodiments, the water-soluble, water-based biodegradable polymer layer according to the present invention comprises a defoaming agent. Suitable defoaming agents include, but are not limited to, polydimethylsiloxane and hydrocarbon blends. Preferably, the water-soluble polymer layer comprises between 0.001% and 0.5% by weight, more preferably from about 0.01% to about 0.1% by weight of the defoaming agent.

[0093] The biodegradable paper barrier laminate according to the present invention may contain residual moisture, depending on the hygroscopicity and isotherms of the laminate components at given temperature and humidity conditions as measured by Karl Fischer titration. For example, a water-soluble polyvinyl alcohol layer may contain approximately 4% to 8% residual moisture at 23°C and 50% relative humidity.

[0094] Water-dispersible nanosheets

[0095] Nanosheets are solid, sheet-like nanoparticles characterized by a high aspect ratio between diameter and orthogonal height. The high aspect ratio provides parallel alignment of the nanosheets and a longer diffusion path length for chemicals through the nanosheets, thereby providing a barrier function. It is desirable that the nanosheets be free of defects such as cracks and holes that reduce barrier properties. It is also desirable that the nanosheets peel easily in water for both application purposes (e.g., wet coating) and end-of-life situations (e.g., wastewater treatment plants), but have high viscosity when dry. Nanosheets are currently used in industry as rheology modifiers, flame retardants, anti-corrosion coatings, and / or chemical barriers. Nanosheets can be obtained from natural sources and used as is, or can be purified and modified from natural sources, or can be synthesized in a furnace for purity and performance reasons.

[0096] Natural phyllosilicates (such as serpentine, clay, chlorite and mica) are composed of nanosheets stacked together. Natural clays (such as kaolinite, pyrophyllite, vermiculite and smectite) are composed of nanosheets stacked together and swell in the presence of water. Smectites (such as montmorillonite and hectorite) are composed of nanosheets stacked together and swell most easily in the presence of water. Natural smectites can be purified and modified, such as sodium Crosset from BYK, which is made of bentonite (a natural mineral containing 60% to 80% montmorillonite) and cation exchanged with monovalent sodium for stripping purposes. Montmorillonites can also be synthesized, such as synthetic hectorite from BYK and sodium hectorite from the University of Bayreuth. Other nanosheets are graphene and graphene oxides, such as those provided by Applied Graphene Materials, and are also characterized by a high aspect ratio between diameter and its orthogonal height.

[0097] Method for preparing biodegradable paper barrier laminate

[0098] There are many non-limiting embodiments of methods for making the biodegradable paper barrier laminates described herein. Figure 5 As shown, a biodegradable paper barrier laminate with an integrated water-dispersible barrier function can be prepared by multiple steps of coating and drying an aqueous water-soluble polymer solution or an aqueous waterborne polymer dispersion and an aqueous nanoplatelet dispersion under specific conditions.

[0099] If an aqueous polymer dispersion is used to prepare the biodegradable polymer layer, additional heating and calendaring steps may be useful to flatten it. In some embodiments, the biodegradable polymer layer may additionally be obtained via hot extrusion coating, or may be attached via a biodegradable tie layer to form a biodegradable paper barrier laminate.

[0100] In a first embodiment, a method of making a biodegradable paper barrier laminate comprises:

[0101] a) applying a first aqueous system of an aqueous biodegradable polymer composition onto the surface of a removable flat carrier such as a PET film, a stainless steel tape, a fluorinated polymer tape or any other suitable carrier material 50

[0102] b) removing water from the first aqueous system of the aqueous biodegradable polymer composition to obtain a first biodegradable polymer layer 40

[0103] c) applying an aqueous dispersion of hydrophilic nanosheets onto the outer surface of the first biodegradable polymer layer 40

[0104] d) Removing water from the aqueous dispersion of hydrophilic nanosheets to obtain a water-dispersible barrier layer 30

[0105] e) applying a second aqueous system of an aqueous polymer composition to the inner surface of the biodegradable paper layer 10

[0106] f) bonding the outer surface of the water-dispersible barrier layer 30 to the second aqueous system of the aqueous polymer composition

[0107] g) removing water from the second aqueous system of the aqueous biodegradable polymer composition to obtain a second biodegradable polymer layer 20

[0108] f) Removing the flat carrier from the resulting biodegradable paper barrier laminate 150 .

[0109] In a second embodiment, a method of making a biodegradable paper barrier laminate comprises:

[0110] a) applying a first aqueous system of an aqueous biodegradable polymer composition onto the surface of a removable flat carrier such as a PET film, a stainless steel tape, a fluorinated polymer tape or any other suitable carrier material 50

[0111] b) removing water from the first aqueous system of the aqueous biodegradable polymer composition to obtain a first biodegradable polymer layer 40

[0112] c) applying heat to the first biodegradable polymer layer 40 to form a flat and continuous first biodegradable polymer layer 40

[0113] d) applying an aqueous dispersion of hydrophilic nanosheets to the outer surface of the first biodegradable polymer layer 40

[0114] e) Removing water from the aqueous dispersion of hydrophilic nanosheets to obtain a water-dispersible barrier layer 30

[0115] f) applying a second aqueous system of an aqueous polymer composition to the inner surface of the biodegradable paper layer 10

[0116] g) bonding the outer surface of the water-dispersible barrier layer 30 to the second aqueous system of the aqueous polymer composition

[0117] h) removing water from the second aqueous system of the aqueous biodegradable polymer composition to obtain a second biodegradable polymer layer 20

[0118] i) Removing the flat carrier from the resulting biodegradable paper barrier laminate 150 .

[0119] In a third embodiment, a method of making a biodegradable paper barrier laminate comprises:

[0120] a) applying a first aqueous system of an aqueous biodegradable polymer composition to the inner surface of the biodegradable paper layer 10, the inner surface being sized, varnished, or both sized and varnished

[0121] b) removing water from the first aqueous system of the aqueous polymer composition to obtain a first biodegradable polymer layer 20

[0122] c) Applying an aqueous dispersion of hydrophilic nanosheets to the inner surface of the first biodegradable polymer layer 20

[0123] d) Removing water from the aqueous dispersion of hydrophilic nanosheets to obtain a water-dispersible barrier layer 30

[0124] e) applying a second aqueous system of an aqueous biodegradable polymer composition to the inner surface of the water-dispersible barrier layer 30

[0125] f) removing water from the aqueous system of the aqueous biodegradable polymer composition to obtain a second biodegradable polymer layer 40 .

[0126] In a fourth embodiment, a method of making a biodegradable paper barrier laminate comprises:

[0127] a) applying a first aqueous system of an aqueous biodegradable polymer composition to the inner surface of the biodegradable paper layer 10, the inner surface being sized, varnished, or both sized and varnished

[0128] b) removing water from the first aqueous system of the aqueous polymer composition to obtain a first biodegradable polymer layer 20

[0129] c) applying heat to the first biodegradable polymer layer 20 to form a continuous layer of the first biodegradable polymer layer 20

[0130] d) applying an aqueous dispersion of hydrophilic nanosheets onto the inner surface of the first biodegradable polymer layer 20

[0131] e) Removing water from the aqueous dispersion of hydrophilic nanosheets to obtain a water-dispersible barrier layer 30

[0132] f) applying a second aqueous system of an aqueous biodegradable polymer composition to the inner surface of the water-dispersible barrier layer 30

[0133] g) removing water from the aqueous system of the aqueous biodegradable polymer composition to obtain the second biodegradable polymer layer 40 .

[0134] The last two methods provide better bond strength between the biodegradable paper layer 10 and the water-dispersible barrier layer 30. They are also simpler to implement from an industrial perspective. However, they limit the choice of biodegradable paper to papers suitable for coating with aqueous polymer systems, such as paper sized on at least one side, or mechanically glazed on at least one side, or kraft or glassine paper. In some cases, sizing and mechanical glazing can be combined to achieve a smoother surface for the biodegradable paper 10.

[0135] In a fifth embodiment, a method of making a biodegradable paper barrier laminate comprises:

[0136] a) applying a first aqueous system of an aqueous biodegradable polymer composition to the inner surface of the biodegradable paper layer 10, the inner surface being sized, varnished, or both sized and varnished

[0137] b) removing water from the first aqueous system of the aqueous biodegradable polymer composition to obtain a first biodegradable polymer layer 20

[0138] c) Applying an aqueous dispersion of hydrophilic nanosheets to the inner surface of the first biodegradable polymer layer 20

[0139] d) Removing water from the aqueous dispersion of hydrophilic nanosheets to obtain a water-dispersible barrier layer 30

[0140] e) melting the second biodegradable polymer composition in an extruder

[0141] f) hot extruding the molten second biodegradable polymer composition onto the surface of the water-dispersible barrier layer 30

[0142] g) cooling the melted second biodegradable polymer composition to form a second biodegradable polymer layer 40 .

[0143] In a sixth embodiment, a method of making a biodegradable paper barrier laminate comprises:

[0144] a) applying a first aqueous system of an aqueous biodegradable polymer composition to the inner surface of the biodegradable paper layer 10, the inner surface being sized, varnished, or both sized and varnished

[0145] b) removing water from the first aqueous system of the aqueous biodegradable polymer composition to obtain a first biodegradable polymer layer 20

[0146] c) applying heat to the first biodegradable polymer layer 20 to form a continuous layer of the first biodegradable polymer layer 20

[0147] d) applying an aqueous dispersion of hydrophilic nanosheets onto the inner surface of the first biodegradable polymer layer 20

[0148] e) Removing water from the aqueous dispersion of hydrophilic nanosheets to obtain a water-dispersible barrier layer 30

[0149] f) melting the second biodegradable polymer composition in an extruder

[0150] g) hot extruding the molten second biodegradable polymer composition onto the surface of the water-dispersible barrier layer 30

[0151] h) cooling the melted second biodegradable polymer composition to form a second biodegradable polymer layer 40 .

[0152] The last two methods do not require the application of a water-based polymer composition to form the heat seal layer 40. Instead, the heat seal layer 40 is attached to the water-dispersible barrier layer 30 via hot extrusion coating of a biodegradable polymer composition.

[0153] In a seventh embodiment, a method of making a biodegradable paper barrier laminate comprises:

[0154] a) applying a first aqueous system of an aqueous biodegradable polymer composition to the inner surface of the biodegradable paper layer 10, the inner surface being sized, varnished, or both sized and varnished

[0155] b) removing water from the first aqueous system of the water-soluble biodegradable polymer composition to obtain a first biodegradable polymer layer 20

[0156] c) Applying an aqueous dispersion of hydrophilic nanosheets to the inner surface of the first biodegradable polymer layer 20

[0157] d) Removing water from the aqueous dispersion of hydrophilic nanosheets to obtain a water-dispersible barrier layer 30

[0158] e) Applying a biodegradable adhesive to the inner surface of the water-dispersible barrier layer 30

[0159] f) obtaining said film 40 made of the biodegradable polymer composition by various methods including solution casting, hot cast film extrusion and hot blown film extrusion

[0160] g) Applying said film 40 made of the biodegradable polymer composition onto the surface of the biodegradable adhesive.

[0161] In an eighth embodiment, a method of making a biodegradable paper barrier laminate comprises:

[0162] a) applying a first aqueous system of an aqueous biodegradable polymer composition to the inner surface of the biodegradable paper layer 10, the inner surface being sized, varnished, or both sized and varnished

[0163] b) removing water from the first aqueous system of the water-soluble biodegradable polymer composition to obtain a first biodegradable polymer layer 20

[0164] c) applying heat to the first biodegradable polymer layer 20 to form a continuous layer of the first biodegradable polymer layer 20

[0165] d) applying an aqueous dispersion of hydrophilic nanosheets onto the inner surface of the first biodegradable polymer layer 20

[0166] e) Removing water from the aqueous dispersion of hydrophilic nanosheets to obtain a water-dispersible barrier layer 30

[0167] f) Applying a biodegradable adhesive to the inner surface of the water-dispersible barrier layer 30

[0168] g) obtaining said film made of the biodegradable polymer composition by various methods including solution casting, hot cast film extrusion and hot blown film extrusion;

[0169] h) Applying said film 40 made of the biodegradable polymer composition onto the surface of the biodegradable adhesive.

[0170] The last two methods do not require the application of a water-based polymer composition to form the heat seal layer 40. Instead, the heat seal layer 40 is attached to the water-dispersible barrier layer 30 via adhesive lamination of a biodegradable polymer composition.

[0171] In order to prepare the biodegradable polymer layer 20 or 40 from a water-soluble aqueous polymer composition, a water-soluble polymer in solid form is typically first dissolved in water by moderate stirring to form an aqueous polymer solution, typically 20% by weight of the water-soluble polymer to 80% by weight of water. The aqueous polymer solution is then further combined with other additives such as a plasticizer under moderate stirring and elevated temperature to form an aqueous polymer system. The aqueous polymer system is then coated onto a flat surface carrier (e.g., untreated PET film, stainless steel tape, fluorinated polymer tape, or any other suitable material) and water is removed via convection or diffusion drying.

[0172] Without being limited by theory, it is believed that important material properties of the aqueous polymer system where the polymer is water-soluble are: a) the solubility of the polymer in water at a given temperature between 20°C and 95°C; b) the resulting viscosity of the aqueous polymer system at that temperature, with higher viscosities being more favorable for maximum differentiation / separation between the layers; and c) the wetting of the aqueous polymer system on the flat support or on the water-dispersible nanosheet layer or on another biodegradable polymer layer, with higher wetting being more favorable.

[0173] In order to prepare the water-based biodegradable polymer layer 20 or 40 from an aqueous polymer composition in which the polymer is water-insoluble, a pre-made dispersion or emulsion of the biodegradable polymer is obtained from the manufacturer, or if a pre-made emulsion is not available, a dispersion or emulsion must be formed. The aqueous polymer system is then coated onto a flat surface support (e.g., untreated PET film, stainless steel tape, fluorinated polymer tape, or any other suitable material) and water is removed via convection or diffusion drying. The applied heat must also be sufficient to form a continuous polymer layer.

[0174] Without being limited by theory, it is believed that important material properties of aqueous polymer systems where the polymer is water-insoluble are: a) the ability to make an emulsion of the biodegradable polymer in water at a given temperature between 20°C and 95°C; b) the resulting viscosity of the aqueous polymer system at that temperature, with higher viscosities being more favorable for maximum differentiation / separation between the layers; and c) the wetting of the aqueous polymer system on a flat support or on a water-dispersible nanosheet layer or on another biodegradable polymer layer, with higher wetting being more favorable.

[0175] The drying step is usually carried out by a belt dryer, such as GmbH & Co KG (Hamburg, Germany) under the trade name Drytec, Coatema Coating Machinery GmbH (Dormagen, Germany) under the trade name ModulDry, and / or FMP Technologies GmbH (Erlangen, Germany) under the trade name SenDry or PureDry. In some embodiments, the drying substrate is guided through a hot air tunnel by a running belt (belt dryer), by a plurality of idler rollers (roller dryer), or by a plurality of hot air nozzles (contactless hot air dryer). Without being limited by theory, it is believed that the most important parameters of the drying process are: the residence time of the drying substrate in the hot air tunnel, which is typically about 50 seconds for a 60μ thick aqueous polymer system (wherein the polymer is water-soluble and contains 25% solids); the temperature of the hot air, which is typically about 95°C; and the flow velocity of the hot air over the substrate, which is typically about 25 m / s. The heating system can be electric, hot oil, steam, or gas.

[0176] For aqueous polymer systems in which the biodegradable polymer is water-insoluble, an additional heating step may be required after drying to form a continuous polymer layer. For example, after coating an aqueous biodegradable PHA dispersion onto a substrate and removing the water by heating the dispersion at 105°C, an additional heating step at 170°C for 30 seconds is performed to melt the PHA and close the pores between the dried white PHA particles. This provides a continuous, transparent PHA layer. If the PHA layer is sufficiently thin, the drying and melting steps can also be combined.

[0177] In some embodiments, it may be preferred that the polymer system is not solely aqueous, but rather that the aqueous polymer system also contains alcohol or another solvent in a proportion of 0 to 100%. In this case, a special drying system may be required to safely remove the alcohol or solvent.

[0178] To prepare the water-dispersible nanosheet layer 30, water-dispersible nanosheets are typically formed by taking solid water-dispersible nanosheets and first exfoliating them in water using high-energy ball milling, typically 80% by weight of water-dispersible nanosheets to 20% by weight of water. The aqueous nanosheet dispersion is then further diluted in water under moderate temperature and vigorous stirring. The aqueous nanosheet dispersion is then coated onto a biodegradable polymer layer and the water is removed by drying.

[0179] Without being limited by theory, it is believed that the important material properties of the nanosheets are: a) the aspect ratio of the nanosheets (larger aspect ratios are more favorable for barrier properties); b) complete exfoliation and dispersion of the nanosheets in water under strong shear mixing, without reagglomeration of the nanosheets, resulting in a substantially uniform coating of uniformly distributed nanosheets, such that the uniform coating is free of defects such as pinholes or cracks. Without being limited by theory, it is also believed that the most important processability properties of the aqueous nanosheet dispersion are: the viscosity of the aqueous nanosheet dispersion, with higher viscosities being more favorable for maximum differentiation / separation between the layers and, therefore, maximum barrier properties; the wetting of the aqueous nanosheet dispersion on a water-soluble polymer layer or on another water-dispersible nanosheet layer; the shear applied to the aqueous nanosheet dispersion, with higher shear being more favorable for parallel nanosheet orientation with respect to the barrier plane; and the removal of water from the dispersion via diffusion drying without the creation of defects in the nanosheet layer.

[0180] A number of methods were tested for coating the aqueous nanosheet dispersion: wire rod coating, anilox roll coating, reverse roll coating, slot die extrusion coating, roll-to-roll coating, and spray coating. Aqueous extrusion coating via a custom slot die (e.g., FMP Technology, Coatema) proved to be the most reliable method for providing adequate feeding of the aqueous nanosheet dispersion, while the roll-to-roll method provided the best barrier properties due to excellent shearing of the aqueous nanosheet dispersion (thus excellent parallel orientation of the nanosheets, and therefore excellent barrier properties). However, the barrier properties also depended on the total thickness of the aqueous nanosheet layer. Typically, the thickness of the aqueous nanosheet layer was in the range of about 0.1 μm to about 20 μm to provide adequate barrier properties while maintaining sufficient mechanical flexibility and mechanical resistance.

[0181] In another non-limiting embodiment of this method, the water-dispersible nanosheet barrier layer 30 is obtained by multiple application steps of coating and drying an aqueous nanosheet dispersion, with each nanosheet sublayer masking any defects in the underlying nanosheet sublayer, thereby providing maximum barrier performance. To this end, a first water-dispersible nanosheet barrier sublayer is formed on the water-soluble polymer layer 10 according to any of the methods described above; subsequently, one or more additional water-dispersible nanosheet barrier sublayers can be added until the desired water-dispersible nanosheet layer thickness is achieved. Following this method, a relatively thick layer of water-dispersible nanosheets can be formed within the water-soluble film. Where increased optical clarity and mechanical flexibility are desired, additional water-dispersible nanosheet barrier sublayers can be separated by additional, thinner water-soluble polymer sublayers. The various polymer sublayers or barrier sublayers can have substantially the same chemical composition or different chemical compositions to provide different properties to the overall structure. Adhesion between the sublayers is provided solely by molecular interactions between the water-soluble polymer and the hydrophilic nanosheets. Similarly, cohesion between the sublayers is provided solely by molecular interactions between materials of the same composition or chemistry, without the use of a binder. The absence of a binder will maximize the barrier properties against water penetration and maintain the dispersibility of the nanosheets in water after the top / bottom polymer layers are dissolved or dispersed.

[0182] In other embodiments, the biodegradable polymer layer 40 is laminated to the water-dispersible barrier layer 30. In one embodiment, lamination involves curtain coating the biodegradable polymer melt onto the water-dispersible barrier layer at a speed of about 100 m / min to 250 m / min and cooling via contact with a chill roll. The curtain is obtained by extruding the biodegradable polymer melt through a slot die.

[0183] In another embodiment, lamination involves applying a solution-based adhesive to an already formed biodegradable polymer film and bonding it to the paper barrier laminate. Non-limiting methods of film preparation are hot cast extrusion or hot blown extrusion or solution casting. Non-limiting examples of adhesives include acrylics, polyvinyl acetate, and other common adhesive tie layers suitable for polar materials. In such embodiments, the adhesive may be Epotal 3702 available from BASF or may be available from Berkshire Labels.

[0184] Inks, Labels and Decorations

[0185] The biodegradable paper barrier laminate according to the present invention may be opaque or translucent. The biodegradable paper barrier laminate according to the present invention may include a printed area. Printing may be achieved using standard printing techniques such as flexographic printing, gravure printing, or inkjet printing.

[0186] The biodegradable paper barrier laminate according to the present invention can be arranged as packaging in a myriad of configurations. For example, the package may include multiple sheets that enclose multiple articles. Each of the sheets includes an inner surface and an outer surface. The outer and / or inner surfaces of one or more sheets may include ink or dye to form a brand, packaging information, and / or background color, etc. on the package. Branding and / or other packaging information associated with the product within the package is provided on the outer surface of at least one sheet. The branding may include a logo, trade name, trademark, icon, etc., associated with the product within the package. The branding is utilized to inform consumers of the product within the package. The packaging information may include product dimensions, the number of products within the package, an exemplary image of the product within the package, recyclability logos, etc.

[0187] In all aspects of the present invention, the ink deposited can be solvent-based or water-based, and the pigment in the ink can be organic or inorganic, or a combination of the two. In some embodiments, the ink is highly wear-resistant. For example, a highly wear-resistant ink may include a coating cured by ultraviolet radiation (UV) or electron beam (EB). In some embodiments, any organic pigment in the ink is derived from a petroleum source. In some embodiments, any organic pigment in the ink is derived from a renewable resource, such as soybeans, plants. In some embodiments, if the pigment is organic, any organic pigment in the ink will be biodegradable. In other embodiments, any inorganic pigment in the ink will be made of dispersible and environmentally friendly inorganic metal oxides.

[0188] Non-limiting examples of inks include ECO-SUREITM available from Gans Ink & Supply Co. and solvent-based inks available from EFI. and BioVu™ inks, which are derived entirely from renewable resources (e.g., corn). Others include SunVisto AquaGreen from Sun Chemicals.

[0189] The ink is present at a thickness of about 0.5 μm to about 20 μm, preferably about 1 μm to about 10 μm, more preferably about 2.5 μm to about 3.5 μm.

[0190] The biodegradable paper barrier laminates disclosed herein may include inks and / or dyes to provide a background color to the packaging disclosed herein. To further illustrate the background color, it is worth noting that the paper layer includes a base color. The base color of the paper layer is the color of the packaging without ink or dye. For example, bleached paper is white, unbleached paper is brown, straw-derived paper is green, and paper containing recyclable content is gray. The background color is any color other than the base color, such as blue, red, green, yellow, purple, orange, black, or a combination thereof. However, if the color is obtained through ink and / or dye, the background color may also include white, brown, or gray.

[0191] In order to reduce the use of ink / dye to facilitate the recycling process, the natural color of the paper layer can be utilized. For example, the ink / dye can be used to define the background color of only the consumer-facing sheet, while the natural color of the paper layer will be used as the background color for the other sheets of the flexible packaging.

[0192] Surface coating

[0193] In some embodiments, the printed surface of the biodegradable paper barrier laminate is surface-coated to protect the ink layer from its physical and chemical environment, enhance the durability of the paper layer, and provide a high-gloss or matte finish. This optional surface coating may be referred to as a lacquer, varnish, or anti-splatter layer. In some embodiments, the surface coating is made from nitrocellulose lacquer, acrylic lacquer, water-based lacquer, or reactive two-component polyurethane lacquer. In some preferred embodiments, the surface coating is made from a natural wax that passes the OECD 301B biodegradation screening test, such as beeswax, rapeseed wax, candelilla wax, soy wax, or other natural wax, provided that the exposure temperature does not exceed the wax melting point. Because the thickness of the surface coating affects the recyclability and biodegradability of packaging made from the recyclable paper barrier laminate of the present invention, thinner surface coatings are preferred. The thickness of the surface coating is preferably between 0.1 μm and 25 μm, more preferably less than 10 μm, and even more preferably less than 5 μm.

[0194] Method for preparing biodegradable paper packaging

[0195] The biodegradable paper barrier laminates described herein can be formed into articles, including but not limited to articles in which typical films or sealable papers would be used as packaging materials. Such articles include but are not limited to bags, pouches, bags, flow wraps, pillow bags, and other containers. Bags, pouches, bags, flow wraps, pillow bags, and other such containers incorporating the biodegradable paper barrier laminates described herein can be prepared in any suitable manner known in the art.

[0196] The biodegradable paper barrier laminates prepared according to the present invention can be converted into packaging and articles using a form-fill-seal process (FFS). Traditional FFS processes typically involve three consecutive steps, wherein the package or article is formed from the paper laminate, filled, and then sealed or closed, as described in U.S. Patent No. 6,293,402, which is incorporated herein by reference. In heat sealing processes, there is a temperature range above which the seal will burn and below which the seal will not be strong enough. The seal is provided in any sealing manner known to those skilled in the art. Sealing can include applying a continuously heated element to the paper laminate and then removing the element after sealing. The heating element can be a hot rod comprising rotating jaws or heating wheels. Different seal types include fin seals and overlapping seals.

[0197] Single-channel method

[0198] A well-known single-pass sealing method using a vertical form and fill machine is described in U.S. Patent No. 4,521,437, which is incorporated herein by reference. In this method, a flat web material is unwound from a roll and formed into a continuous tube by sealing the longitudinal edges of the film together to form a lap seal (i.e., a fin seal). The resulting tube is pulled vertically downward to a filling station and collapsed into a cross-section of the tube at a sealing device located below the filling station. A transverse heat seal is formed by the sealing device at the collapsed section of the tube, creating an airtight seal across the tube. After the transverse seal is formed, a predetermined volume of the material to be packaged (e.g., a flowable material) enters the tube at the filling station and fills the tube upward from the transverse seal. The tube then drops a predetermined distance under the influence of the weight of the material in the tube and the weight of the film advancing mechanism on the machine. The jaws of the sealing device close, collapsing the tube at a second cross-section located above the air / material interface in the tube. The sealing device seals and severs the tube transversely at this second cross-section. The material-filled portion of the tube now forms a pillow-shaped pouch. In this way, the sealing device seals the top of the filled pouch, seals the bottom of the next pouch to be formed, and separates the filled pouch from the next pouch to be formed in one operation.

[0199] Multi-channel method

[0200] The packages of the present invention can also be processed using a multi-channel pouch packaging machine (such as the VEGA PACK 300S produced by QuadroPack (Nijeveen, Netherlands)). A high-speed multi-channel pouch processing machine is also described in U.S. Patent No. 6,966,166, which is incorporated herein by reference. The machine used in this method includes two rollers for distributing sheets of web film of equal size, a plurality of sealing devices suitable for such substrates and devices, such as a pump station described below for inserting contents (e.g., liquids, viscous materials, powders, and other substances) into the film package. Multiple packages can be produced by utilizing one or more movable reciprocating carriages that travel with the film flow through the machine, which support each of the sealing and cross-cutting stations. The sealing device is applied to all edges except one, thereby forming a bag having a cavity and an opening. The desired contents of the package are inserted into the cavity through the opening. The opening is then sealed and separated from the substrate. A pair of substrate rollers is provided at the substrate roller station. Alternatively, a cutter can be placed between a single nip roller to divide the substrate width into two equal parts. Sheets of paper laminate are advanced through the machine by a traction wheel station and used to form the front and back sheets of the package. The paper laminate from each roller is guided so that as the two sheets of paper laminate advance through the machine, they are very close to each other and in a parallel relationship. The sealing and cutting equipment includes: longitudinal sealing strips for sealing the vertical edges of the package, one-way rollers for holding the paper laminate in place and preventing it from sliding backward, vertical cutters for cutting the torn slits into the package in the vertical direction, and transverse sealing strips for sealing the package in the horizontal direction. The pump station includes multiple filling dispensers connected to the storage structure that holds the consumer products in the package. These dispensers are capable of extracting a predetermined amount of consumer product from a reservoir and depositing it into the cavity of the paper laminate package formed by the machine. In a preferred embodiment, the pump station and dispensers can be driven by one or more motion-controlled servo motors connected to a cam system. The amount of consumable product can be varied by exchanging dispensers (different dispensers with more or less capacity), changing the stroke of the pump cycle, changing the timing of the pump cycle, etc. Thus, depending on the size and capacity of the packages to be formed by the machine, different amounts of consumable product can be dispensed.

[0201] The sealing mechanism may be a heat seal, a water seal, a moisture seal, an ultrasonic seal, an infrared seal, or any other type of seal deemed suitable.

[0202] Products

[0203] like Figure 7As shown, the present invention also includes an article comprising a product composition 400 and a biodegradable paper barrier laminate 150, which can be formed into a container 350, such as a bag, pouch, capsule, bag, etc., to hold the product composition. For simplicity, the articles of interest herein will be described in terms of biodegradable barrier paper bags, but it should be understood that the discussion herein is also applicable to other types of containers.

[0204] The bag 350 formed by the aforementioned method can be any form and shape suitable for holding the composition 400 contained therein until it is desired to release the composition 400 from the biodegradable paper barrier laminate bag 350, such as by tearing it open. The bag 350 can include one compartment or two or more compartments (i.e., the bag can be a multi-compartment bag). In one embodiment, the biodegradable paper barrier laminate bag 350 can have two or more compartments.

[0205] In one embodiment, a biodegradable paper barrier laminate can be sealed to a water-soluble barrier film without attached paper. This can create a window into the package, allowing the consumer to see the product without changing the recyclability of the package.

[0206] The bag or other container 350 can hold a unit dose of one or more compositions 400 from a range of products, which may include, but are not limited to, consumer products. As used herein, "consumer products" refers to materials used, for example, for hair care, beauty care, oral care, health care, personal cleansing, and household cleaning. Non-limiting examples of consumer products include shampoo, conditioner, mousse, facial soap, hand soap, body soap, liquid soap, bar soap, moisturizer, body lotion, shaving lotion, toothpaste, mouthwash, hair spray, hand sanitizer, laundry detergent compositions, dishwashing detergent, automatic dishwasher detergent compositions, hard surface cleaners, stain removers, fabric enhancers and / or fabric softeners, cosmetics and over-the-counter medications, electronics, pharmaceuticals, candy, pet health products, medical hemp-derived products, industrial hemp-derived products, CBD-based products, other products derived from non-hemp pharmaceuticals, vitamins, non-pharmaceutical natural / herbal "wellness" products, razors, absorbent articles, wipes, hair spray, food and beverages, animal-based foods, menstrual cups, peeling pads, electronic and electrical consumer devices, brushes, applicators, earplugs, eye masks, eye patches, facial masks, agricultural products, plant-based foods, plant seeds, insecticides, anticides, alcoholic beverages, animal-based foods, and new product formats. Typical absorbent articles of the present invention include, but are not limited to, diapers, adult incontinence briefs, training pants, diaper holders, catamenial pads, incontinence pads, liners, absorbent inserts, panty liners, tampons, menstrual pants, sponges, tissues, paper towels, wipes, flannels, and the like.

[0207] The biodegradable paper barrier laminate disclosed herein can be used as primary packaging material for absorbent articles. As used herein, the term "absorbent article" refers to a device that absorbs and contains exudates, and more specifically, refers to a device that is placed against or adjacent to the wearer's body to absorb and contain various exudates discharged from the body. Absorbent articles disclosed herein include, but are not limited to, diapers, adult incontinence briefs, training pants, diaper holders, catamenial pads, feminine hygiene pads, incontinence pads, liners, absorbent inserts, panty liners, tampons, and the like.

[0208] Plastic films have historically been used as primary packaging (the packaging on store shelves) materials for absorbent articles, but the recyclable paper barrier laminates of the present disclosure can be used in addition. The materials of the present invention meet the need for a flexible and resilient natural-type packaging material. The recyclable paper barrier laminates of the present invention meet the need for a natural-type packaging material that can withstand the harsh conditions of the absorbent article packaging process. Furthermore, it meets the need for a natural-type packaging material that exhibits barrier properties and can be easily recycled by the consumer. Even more, the recyclable paper barrier laminates of the present disclosure meet the need for a natural-type barrier packaging material that is perceived by consumers as non-plastic and that is technically verified to be non-plastic.

[0209] The composition 400 within the bag 350 can be in any suitable form, including but not limited to: powder, solid foam, fiber, solid, granules, liquid, gel, paste, cream, capsule, pill, dragee, solid foam, fiber, absorbent article, nonwoven fabric, etc. The bag is particularly suitable for dry products, with the exception of some pastes, gels, and liquid products containing less than 30% water, more preferably less than 20% water. The packaging and articles of the present invention are resistant to consumer products. As used herein, "resistant" refers to the ability of the packaging and articles to maintain their mechanical properties and appearance on their designed surfaces without causing degradation of the packaging and articles by diffusion of consumer products through the packaging material.

[0210] Additional product forms (articles) include disposable aprons, laundry bags, disposable medical bedding, skin patches, face masks, disposable gloves, disposable medical gowns, medical devices, skin wraps, agricultural coverings, shopping bags, refill bags, reloadable components in durable systems, sandwich bags, trash bags, emergency blankets and clothing, building / structural wraps and moisture-barrier liners, primary packaging for shipping such as envelopes and mailing bags, non-absorbent clothing articles that can be used to package clothing such as dresses, shirts, suits and shoes.

[0211] The different compartments of the multi-compartment bag 350 can be used to separate incompatible ingredients. For example, it may be desirable to separate dry shampoo and dry conditioner or laundry detergent and laundry additives into separate compartments.

[0212] Due to the improved water vapor and oxygen barriers, dyes and fragrances commonly used in some products should be more stable inside bags made from biodegradable paper barrier laminates than bags made from non-barrier paper laminates. Also, the barrier to the migration of oils, surfactants, and other chemicals contained within the package may be improved compared to packages made from non-barrier paper laminates.

[0213] At the end of its life, consumers can recycle the packaging in conventional paper recycling systems. The structure will be broken down in a repulping system, allowing the paper fibers to be recovered. The soluble polymer will dissolve and be filtered out, eventually biodegrading, or it can be recovered from the wastewater of a recycling plant for reuse. Any barrier materials are inert, harmless, and naturally occurring, and will disperse safely in wastewater. However, if discarded, the packaging will biodegrade within 6 to 12 months.

[0214] In order to facilitate and promote the recyclability of the packaging, the packaging made from the structure of the present disclosure may contain less than 50% by weight of ink, dye, barrier layer, polymer layer, glue and / or synthetic fiber. The weight percentage of ink, dye, barrier layer, polymer layer, glue and / or synthetic fiber in the packaging may be less than 50% by weight, more preferably less than 30% by weight, or most preferably less than 10% by weight, specifically reciting all values ​​within these ranges and any ranges resulting therefrom. For example, the weight percentage of ink, dye, barrier layer, polymer layer, glue and / or synthetic fiber in the packaging material may be between 0.1% by weight and 50% by weight, more preferably between 0.1% by weight and 30% by weight, or most preferably between 0.1% by weight and 10% by weight, specifically reciting all values ​​within these ranges and any ranges resulting therefrom. In a specific example, the amount of ink, dye, barrier layer, polymer layer, glue and / or synthetic fiber is 5% by weight or less, or between 0.1% by weight and 5% by weight, specifically reciting all values ​​within these ranges and any ranges resulting therefrom.

[0215] Preferably, the resulting overall package made from the biodegradable paper barrier laminate described in the present disclosure comprises at least 50% by weight natural cellulosic fibers, at least 70% by weight natural cellulosic fibers, or at least 80% by weight natural cellulosic fibers, specifically reciting all values ​​within these ranges and any ranges derived therefrom.

[0216] The recyclability of packaging according to the present invention can be determined by a percentage of recyclability. The paper barrier laminate according to the present invention can exhibit a percentage of recyclability of 50% or greater, more preferably 70% or greater, or most preferably 80% or greater, with all values ​​within these ranges and any ranges derived therefrom being specifically recited. The paper barrier laminate according to the present invention can have a percentage of recyclability yield of between 50% and about 99%, more preferably between about 85% and about 99%, or most preferably between about 90% and about 99%.

[0217] Test Method

[0218] When testing and / or measuring materials, if the relevant test method does not specify a specific temperature, the specimens shall be tested and / or measured at a temperature of 23°C (±3°C), wherein such specimens are pre-conditioned to such temperature. When testing and / or measuring materials, if the relevant test method does not specify a specific humidity, the specimens shall be tested and / or measured at a humidity of 35% (±5%), wherein such specimens are pre-conditioned to such humidity. Testing and / or measurements shall be performed by trained, skilled, and experienced personnel using appropriately calibrated equipment and / or instruments in accordance with good laboratory practice.

[0219] 1) Thickness of individual layers / overall laminate

[0220] The thickness of the overall film / individual layer was measured by cutting a 20 μm thick cross section of the film sample using a sliding microtome (e.g., Leica SM2010 R), placing it under an optical microscope (e.g., Leica Diaplan) in light transmission mode, and applying imaging analysis software. The water-dispersible nanosheet layer contrasted strongly with the water-soluble polymer layer. In the case of adjacent water-soluble polymer layers, contrast could be achieved by adding different tracers such as 0.5 wt% rhodamine B or 0.5 wt% titanium dioxide nanoparticles.

[0221] 2) Water Vapor Transmission Rate (WVTR)

[0222] The test method is carried out according to ASTM F1249-13 under the following test conditions: temperature is 40°C (± 0.56°C) and relative humidity is 50% (± 3%). If tropical conditions are required, the temperature is set to 38°C (± 0.56°C) and the relative humidity is set to 90% (± 3%). Water vapor transmission rate is expressed in g / m 2 If normalized by barrier thickness, the water vapor transmission rate is reported in g.μm / m 2 For materials outside the scope of ASTM F-1249-13 (§1.1), the water vapor transmission rate test method is not applicable.

[0223] 3) Biodegradation test

[0224] Aerobic biodegradation is measured by the generation of carbon dioxide (CO2) from sample specimens according to Test Method 301B and Test Guide 306 of Section 3 of the OECD Chemical Testing Guide. OECD 301B applies to both the primary component (paper, barrier layer, sealant) and the final packaging. The final packaging includes all primary and secondary (ink, varnish) components and is open to simulate post-consumer disposal. OECD 306 applies to the final packaging tested in seawater. The pass / fail success criteria are as follows:

[0225]

[0226] *Fully formed bag represents the final form of the bag (containing all dyes and coatings) as it will be disposed of in the environment. The bag will be cut open to simulate being torn open by a consumer.

[0227] The sample should biodegrade at least 60% within 60 days, preferably at least 60% within 28 days.

[0228] Example

[0229] 1. Biodegradable paper barrier laminate based on paper, polyvinyl alcohol and sodium crosette

[0230] Preparation of aqueous sealing layer composition

[0231] 1070g deionized water is heated to 50 ℃ in Thermomix TM5. 400g solid PVOH powder (Selvol 205, deriving from Sekisui Chemicals, Tokyo, Japan) is added under the stirring level of 2.5 to 3.0 and the temperature is set to 85 ℃. When reaching the temperature of 85 ℃ (in about 5 minutes), the stirring level is reduced to 1.0 to 1.5 to avoid extreme foaming. After continuous stirring at 85 ℃ for 30 minutes, the polymer dissolves. In parallel, 50g sorbitol and 50g glycerol are mixed with 100g deionized water at 85 ℃. Then, both polymer and plasticizer solution are mixed for about 5 minutes at 85 ℃ with the stirring level of 1.0 to 1.5. The solution is stored at room temperature overnight to eliminate any residual foam.

[0232] Preparation of aqueous barrier layer composition

[0233] 1120 g of deionized water were heated to 50° C. in a Thermomix TM5. 100 g of a masterbatch paste (CNaMGH from MBN Nanomaterialia, consisting of 80% sodium Crosette from BYK exfoliated in 20% water) was added at a stirring level of 3.0. Crosette is a natural bentonite with an aspect ratio of approximately 200, while natural Ca 2+ Na + Replace to allow it to peel in a polar medium. Once completed, the stirring level was increased to 5.0 and the remaining paste agglomerates were scraped off the mixing container walls / mixer blades. After continuing stirring at a level of 5.0 for 30 minutes, the nanoparticles were uniformly dispersed to form a brown viscous liquid / gel, with some gel remaining on the container walls, which had to be removed using a flexible scraper.

[0234] Preparation of aqueous laminating layer compositions

[0235] 650g of deionized water was heated to 50°C in a Thermomix TM5. 400g of solid PVOH powder (Selvol 205, from Sekisui Chemicals) was added at a stirring level of 2.5 to 3.0 and the temperature was set to 85°C. When a temperature of 85°C was reached (within approximately 5 minutes), the stirring level was reduced to 1.0 to 1.5 to avoid extreme foaming. After continuous stirring at 85°C for 30 minutes, the polymer dissolved. In parallel, 100g of glycerol was mixed with 100g of deionized water at 85°C. Then, both the polymer and the plasticizer solution were mixed together at 85°C with a stirring level of 1.0 to 1.5 for approximately 5 minutes. The solution was stored at room temperature overnight to eliminate any residual foam.

[0236] Preparation of biodegradable paper barrier laminates based on paper, polyvinyl alcohol and sodium crosette

[0237] In one non-limiting embodiment (Sample 1), a first water-soluble polymer sealant layer was formed by extrusion coating a 100 μm aqueous sealant layer composition at 85° C. from FMP Technology onto an untreated PET carrier film (Hostaphan RN 50-350, available from Mitsubishi, Tokyo, Japan) via a slot die, followed by water removal via a convection dryer from FMP Technology set to 95° C. The resulting 34 μm dry layer had a composition of 80% Selvol 205 (available from Sekisui Chemicals), 10% glycerol, and 10% sorbitol. As a next step, a water-dispersible nanoplatelet barrier layer was added by extrusion coating a 60 μm aqueous barrier layer composition at 50° C. from FMP Technology onto the first single water-soluble polymer sealant layer via a slot die, followed by water removal via a convection dryer from FMP Technology set to 95° C. The composition of the resulting 4μ dry layer was 100% sodium Crosset from BYK. Finally, at the Line Laminating & Technology Center (Neuss), the multilayer structure was laminated onto the internally sized side of a recyclable 99μ thick paper grade obtained as NiklaSelect V natural linen paper from Birgl & Bergmeister GmbH (B&B, Styria, Austria), which was coated with a 12μ aqueous laminating layer composition. The water in the solution was absorbed into the paper. The composition of the resulting 5μ dry layer was 80% Selvol 205 (from Sekisui Chemicals) and 20% glycerol (from Cremer).

[0238] In another non-limiting embodiment (Sample 2), a first water-soluble polymer sealant layer was formed by extrusion coating a 100 μm aqueous sealant layer composition at 85° C. from FMP Technology onto an untreated PET carrier film (Hostaphan RN 50-350 from Mitsubishi) via a slot die from FMP Technology, followed by water removal via a convection dryer from FMP Technology set to 95° C. The resulting 34 μm dry layer had a composition of 80% Selvol 205 (from Sekisui Chemicals), 10% glycerol, and 10% sorbitol. As a next step, a first water-dispersible nanoplatelet barrier sublayer was added by extrusion coating a 60 μm aqueous barrier layer composition at 50° C. from FMP Technology onto the first single water-soluble polymer sealant layer via a slot die from FMP Technology, followed by water removal via a convection dryer from FMP Technology set to 95° C. The composition of the resulting 4μ dry layer was 100% sodium Crosset from BYK. A second water-dispersible nanoplatelet barrier sublayer was then added by extrusion coating a 60μ aqueous barrier layer composition at 50°C from FMP Technology onto the first water-dispersible nanoplatelet barrier sublayer via a slot die, followed by removal of the water via a convection dryer from FMP Technology set to 95°C. The composition of the resulting 1μ dry layer was 100% sodium Crosset from BYK. Finally, the multilayer structure was laminated to the inner sized side of a recyclable 99μ thickness paper grade obtained from Birgl & Bergmeister (B&B) as NiklaSelect V natural linen paper, coated with a 12μ aqueous laminating layer composition, at the Line Laminating & Technology Center (Neuss). The water in the solution was absorbed into the paper. The composition of the resulting 5μ dry layer was 80% Selvol 205 (from Sekisui Chemicals) and 20% glycerol (from Cremer).

[0239] In another non-limiting embodiment (Sample 3), a first water-soluble polymer sealant layer was formed by extrusion coating a 100 μm aqueous sealant layer composition at 85° C. from FMP Technology onto an untreated PET carrier film (Hostaphan RN 50-350 from Mitsubishi) via a slot die from FMP Technology, followed by water removal via a convection dryer from FMP Technology set to 95° C. The resulting 34 μm dry layer had a composition of 80% Selvol 205 (from Sekisui Chemicals), 10% glycerol, and 10% sorbitol. As a next step, a first water-dispersible nanoplatelet barrier sublayer was added by roll-to-roll coating a 14 μm aqueous barrier layer composition at room temperature onto the first single water-soluble polymer sealant layer at the Line Laminating & Technology Center (Neuss), followed by water absorption into the first water-soluble polymer layer. The resulting 1 μm dry layer had a composition of 100% sodium Crosset from BYK. A second water-dispersible nanoplatelet barrier sublayer was then added by roll-to-roll coating a 14μ aqueous Crosette dispersion at room temperature onto the first water-dispersible nanoplatelet barrier sublayer at the Line Laminating & Technology Center (Neuss), and the water was then removed by evaporation over a period of one week. The composition of the resulting 0.5μ dry layer was 100% sodium Crosette from BYK. Finally, the multilayer structure was laminated to the inner sized side of a recyclable 99μ thickness paper grade obtained from Birgl & Bergmeister (B&B) as NiklaSelect V natural linen paper, coated with a 12μ aqueous laminating layer composition, at the Line Laminating & Technology Center (Neuss). The water in the solution was absorbed into the paper. The composition of the resulting 5μ dry laminating layer was 80% Selvol 205 (from Sekisui Chemicals) and 20% glycerol (from Cremer).

[0240] Table 3 below provides the barrier properties (WVTR) for the above-described embodiments.

[0241] Table 3

[0242]

[0243] While the barrier properties of the water-dispersible nanosheet monolayer (Sample 1) are suitable for many recyclable paper-based flexible packaging applications, the barrier properties can be significantly improved by dividing the water-dispersible nanosheet monolayer into two sublayers (Sample 2). Without being limited by theory, it is believed that the second sublayer masks any possible defects present in the first sublayer.

[0244] While the barrier performance of the water-dispersible nanosheet double layer applied by extrusion coating (Sample 2) is suitable for many recyclable paper flexible packaging applications, applying the water-dispersible nanosheet double layer via roll-to-roll coating (Sample 3) significantly improves the barrier performance. Without being limited by theory, it is believed that the increased shear of the roll-to-roll coating process better orients the Crosette nanosheets in the plane of the barrier layer, thereby increasing the permeation length in the barrier layer and thus enhancing the barrier performance.

[0245] Table 4 provides the biodegradability and recyclability of the above embodiments.

[0246] Table 4

[0247]

[0248] 2. Biodegradable paper barrier laminate based on paper, PVOH, sodium crosette and PBSA

[0249] Preparation of aqueous laminating layer compositions

[0250] 650g of deionized water was heated to 50°C in a Thermomix TM5. 400g of solid PVOH powder (Selvol 205, from Sekisui Chemicals) was added at a stirring level of 2.5 to 3.0 and the temperature was set to 85°C. When a temperature of 85°C was reached (within approximately 5 minutes), the stirring level was reduced to 1.0 to 1.5 to avoid extreme foaming. After continuous stirring at 85°C for 30 minutes, the polymer dissolved. In parallel, 100g of glycerol was mixed with 100g of deionized water at 85°C. Then, both the polymer and the plasticizer solution were mixed at 85°C at a stirring level of 1.0 to 1.5 for approximately 5 minutes. The solution was stored at room temperature overnight to eliminate any residual foam.

[0251] Preparation of aqueous barrier layer composition

[0252] 1120 g of deionized water were heated to 50° C. in a Thermomix TM5. 100 g of a masterbatch paste (CNaMGH from MBN Nanomaterialia, consisting of 80% sodium Crosette from BYK exfoliated in 20% water) was added at a stirring level of 3.0. Crosette is a natural bentonite with an aspect ratio of approximately 200, while natural Ca 2+ Na +Replace to allow it to peel in a polar medium. Once completed, the stirring level was increased to 5.0 and the remaining paste agglomerates were scraped off the mixing container walls / mixer blades. After continuing stirring at a level of 5.0 for 30 minutes, the nanoparticles were uniformly dispersed to form a brown viscous liquid / gel, with some gel remaining on the container walls, which had to be removed using a flexible scraper.

[0253] Preparation of PBSA for extrusion coating

[0254] PBSA pellet grade FD92PM was obtained from Mitsubishi Chemicals and used as received.

[0255] Preparation of PBSA free-standing membrane

[0256] PBSA pellets grade FD92PM were obtained from Mitsubishi Chemicals.The pellets were melted in an extruder and then formed into films using conventional cast or blown film extrusion techniques.

[0257] Preparation of adhesive composition

[0258] Adhesive grade Epotal 3702 was obtained from BASF and was used for adhesive lamination purposes.

[0259] Preparation of biodegradable paper barrier laminates based on paper, PVOH, sodium crosette and PBSA

[0260] In one non-limiting embodiment, a 12μ aqueous laminating layer composition was applied to the inner sized side of a biodegradable 99μ thick paper grade available from Birgl & Bergmeister (B&B) as NiklaSelect V natural linen paper. The water in the solution was absorbed into the paper, and the remaining water was removed via a convection dryer from FMP Technology set to 95°C. The composition of the resulting 5μ dry layer was 80% Selvol 205 (from Sekisui Chemicals) and 20% glycerol (from Cremer). As a next step, a water-dispersible nanoplatelet barrier layer was added by extrusion coating a 60μ aqueous barrier layer composition at 50°C onto the first single water-soluble polymer sealant layer via a slot die from FMP Technology, followed by water removal via a convection dryer from FMP Technology set to 95°C. The composition of the resulting 4μ dry layer was 100% sodium Crosset from BYK. As a next step, a polymer sealant layer is added by curtain coating a biodegradable polymer melt onto the water dispersible barrier layer at a speed of about 100 to 250 m / min and cooling via contact with a chill roll.The curtain is formed by extruding the biodegradable polymer melt through a slot die.

[0261] In another non-limiting embodiment, a 12μ aqueous laminating layer composition was applied to the inner sized side of a biodegradable 99μ thick paper grade available from Birgl & Bergmeister (B&B) as NiklaSelect V natural linen paper. The water in the solution was absorbed into the paper, and the remaining water was removed via a convection dryer from FMP Technology set to 95°C. The composition of the resulting 5μ dry layer was 80% Selvol 205 (from Sekisui Chemicals) and 20% glycerol (from Cremer). As a next step, a water-dispersible nanoplatelet barrier layer was added by extrusion coating a 60μ aqueous barrier layer composition at 50°C onto the first single water-soluble polymer sealant layer via a slot die from FMP Technology, followed by water removal via a convection dryer from FMP Technology set to 95°C. The composition of the resulting 4μ dry layer was 100% sodium Crosset from BYK. As a next step, a solution-based adhesive composition, Epotal 3702, from BASF, was coated onto the water-dispersible barrier layer, and the solvent was removed via a convection dryer from FMP Technology set to 95° C. to form an adhesive layer. As a next step, a PBSA film was bonded to the adhesive layer to deliver a heat-sealable, biodegradable paper barrier laminate.

[0262] Comparative Example

[0263] A. Non-biodegradable paper barrier laminates based on polyvinyl alcohol and polyvinyl chloride

[0264] Preparation of aqueous sealing layer composition

[0265] 1070g of deionized water was heated to 50°C in a Thermomix TM5. 400g of solid PVOH powder (Selvol 205, from Sekisui Chemicals) was added at a stirring level of 2.5 to 3.0 and the temperature was set to 85°C. When the temperature reached 85°C (in about 5 minutes), the stirring level was reduced to 1.0 to 1.5 to avoid extreme foaming. After continuous stirring at 85°C for 30 minutes, the polymer dissolved. In parallel, 50g of sorbitol and 50g of glycerol were mixed with 100g of deionized water at 85°C. Then, the polymer and plasticizer solutions were mixed together at 85°C with a stirring level of 1.0 to 1.5 for about 5 minutes. The solution was stored at room temperature overnight to eliminate any residual foam.

[0266] Preparation of non-aqueous barrier layer composition

[0267] 1000g methyl ethyl ketone (MEK) and ethyl acetate (EA) solvent mixture (60:40) is heated to 50 ℃ in a glass beaker in a protective fume hood. 200g of polyvinyl chloride (PVDC) powder grade resin F310 deriving from Asahi Kasei is added under magnetic stirring. Once completed, the stirring level is increased to the maximum level and heating is turned off. After continuous stirring for about 2 hours at the maximum level, the PVDC powder is completely dissolved. The solution is stored overnight at room temperature (RT) to eliminate any residual foam.

[0268] Preparation of aqueous laminating layer compositions

[0269] 650g of deionized water was heated to 50°C in a Thermomix TM5. 400g of solid PVOH powder (Selvol 205, from Sekisui Chemicals) was added at a stirring level of 2.5 to 3.0 and the temperature was set to 85°C. When a temperature of 85°C was reached (within approximately 5 minutes), the stirring level was reduced to 1.0 to 1.5 to avoid extreme foaming. After continuous stirring at 85°C for 30 minutes, the polymer dissolved. In parallel, 100g of glycerol was mixed with 100g of deionized water at 85°C. Then, both the polymer and the plasticizer solution were mixed together at 85°C with a stirring level of 1.0 to 1.5 for approximately 5 minutes. The solution was stored at room temperature overnight to eliminate any residual foam.

[0270] Preparation of paper barrier laminates based on polyvinyl alcohol and polyvinyl dichloride

[0271] In one non-limiting embodiment, a first water-soluble polymer sealant layer is formed by extrusion coating a 100μ aqueous sealant layer composition at 85°C from FMP Technology onto an untreated PET carrier film (Hostaphan RN 50-350 from Mitsubishi) via a slot die, followed by removal of water via a convection dryer from FMP Technology set to 95°C. The resulting 34μ dry layer has a composition of 80% Selvol 205 (from Sekisui Chemicals), 10% glycerol, and 10% sorbitol. As a next step, a first non-dispersible barrier sublayer is added by coating a 30μ non-aqueous barrier layer composition at 50°C onto the first single water-soluble polymer sealant layer via an anilox roll, followed by removal of the MEK / EA solvent via a convection dryer from Drytec set to 95°C. The composition of the resulting 3μ dry layer was 100% PVDC grade F310 (available from Asahi Kasei). A second non-dispersible barrier sublayer was then added by coating a 30μ non-aqueous barrier layer composition at 50°C onto the first single water-soluble polymer sealant layer via an anilox roll, followed by removal of the MEK / EA solvent via a convection dryer from Drytec set to 95°C. The composition of the resulting 3μ dry layer was 100% PVDC grade F310 (available from Asahi Kasei). Finally, the multilayer structure was laminated to the inner sized side of a recyclable 65μ thickness paper grade available from Birgl & Bergmeister (B&B) as PackPro 7.0, coated with a 12μ aqueous laminating layer composition, at the Line Laminating & Technology Center (Neuss). The water in the solution was absorbed into the paper. The composition of the resulting 5μ dry layer was 80% Selvol 205 (from Sekisui Chemicals) and 20% glycerol (from Cremer).

[0272] While such PVdC samples (which have been commonly used in the packaging industry for the past 20 years) will provide a moisture barrier similar to a clay barrier at 40°C / 50% RH, the PVdC barrier will not disperse harmlessly in nature if the packaging is discarded because PVdC is made of non-biodegradable plastic and, therefore, may form microplastics once the packaging begins to decompose in the environment. Furthermore, it would not be desirable to disperse easily in the hot water of a paper repulping facility or if it were to end up in the environment as litter. In fact, despite its excellent barrier properties, many companies may prohibit the use of PVdC due to the potential for chlorine emissions during production and at end-of-life combustion. Clay barriers are considered a more environmentally friendly barrier than PVdC.

[0273] The dimensions and values ​​disclosed herein are not to be understood as being strictly limited to the exact numerical values ​​recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm."

[0274] Unless expressly excluded or otherwise limited, each document cited herein, including any cross-referenced or related patent or patent application and any patent application or patent to which this application claims priority or the benefit of, is hereby incorporated by reference in its entirety. The citation of any document is not an admission that it is prior art to any of the present inventions disclosed or claimed herein, or an admission that it, by itself or in combination with any one or more references, proposes, suggests, or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

[0275] Although specific embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications may be made without departing from the spirit and scope of the invention. It is therefore intended that all such changes and modifications within the scope of the invention be encompassed in the appended claims.

Claims

1. A biodegradable paper barrier laminate comprising: a) a biodegradable paper layer having an outer surface and an inner surface; b) a first biodegradable polymer layer having an outer surface and an inner surface and having a thickness of 1 μm to 5 μm, the outer surface being disposed on the inner surface of the paper layer; c) a water-dispersible barrier layer comprising 96% to 100% hydrophilic nanoplatelets having an outer surface and an inner surface, the outer surface being disposed on the inner surface of the first biodegradable polymer layer, wherein the hydrophilic nanoplatelets comprise sodium crosette; d) a second biodegradable polymer layer having an outer surface and an inner surface, said outer surface being disposed on said inner surface of said water-dispersible barrier layer, The biodegradable paper barrier laminate achieves at least 60% biodegradation within 60 days in an OECD 301B test.

2. The biodegradable paper barrier laminate according to claim 1, comprising an additional biodegradable adhesive layer having an outer surface and an inner surface.

3. The biodegradable paper barrier laminate according to claim 1, wherein the grammage of the biodegradable paper barrier laminate is 20 g / m 2 Up to 1000g / m 2 .

4. The biodegradable paper barrier laminate according to claim 3, wherein the grammage of the biodegradable paper barrier laminate is 20 g / m 2 Up to 200g / m 2 .

5. The biodegradable paper barrier laminate according to any one of claims 1 to 4, wherein the WVTR of the biodegradable paper barrier laminate is 0.1 g / m2 when measured according to ASTM method F1249-13 at a temperature of 40°C and a relative humidity of 50%. 2 / day to 100g / m 2 / sky.

6. The biodegradable paper barrier laminate according to any one of claims 1 to 4, wherein the WVTR of the biodegradable paper barrier laminate is 0.1 g / m2 when measured according to ASTM method F1249-13 at a temperature of 38°C and a relative humidity of 90%. 2 / day to 200g / m 2 / sky.

7. The biodegradable paper barrier laminate according to any one of claims 1 to 4, wherein the WVTR of the biodegradable paper barrier laminate is 0.1 g / m2 when measured according to ASTM method F1249-13 at a temperature of 40°C and a relative humidity of 50%. 2 / day to 200g / m 2 / sky.

8. The biodegradable paper barrier laminate according to any one of claims 1 to 4, wherein the biodegradable paper barrier laminate is recyclable and exhibits a recycling percentage of at least 50% as determined by test method PTS-RH:021 / 97.

9. The biodegradable paper barrier laminate of claim 8, wherein the biodegradable paper barrier laminate is recyclable and exhibits a percent recyclability of at least 70% as determined by test method PTS-RH:021 / 97.

10. The biodegradable paper barrier laminate of claim 8, wherein the biodegradable paper barrier laminate is recyclable and exhibits a recyclability percentage of at least 80% as determined by test method PTS-RH:021 / 97.

11. The biodegradable paper barrier laminate according to any one of claims 1 to 4, wherein the biodegradable paper barrier laminate comprises 50% to 100% by weight of natural fibers.

12. The biodegradable paper barrier laminate according to claim 11, wherein the biodegradable paper barrier laminate comprises 65% to 99% by weight of natural fibers.

13. The biodegradable paper barrier laminate of claim 11, wherein the biodegradable paper barrier laminate comprises 75% to 95% by weight natural fibers.

14. The biodegradable paper barrier laminate according to any one of claims 1 to 4, wherein the average thickness of the second biodegradable polymer layer is from 1 μm to 200 μm.

15. The biodegradable paper barrier laminate according to claim 14, wherein the average thickness of the second biodegradable polymer layer is from 1 μm to 100 μm.

16. The biodegradable paper barrier laminate according to claim 14, wherein the average thickness of the second biodegradable polymer layer is from 1 μm to 50 μm.

17. The biodegradable paper barrier laminate according to any one of claims 1 to 4, wherein the biodegradable polymer layer comprises at least one water-insoluble polymer selected from the group consisting of polyhydroxyalkanoate, polybutylene succinate, polybutylene succinate-co-adipate, polybutylene adipate-co-terephthalate, polylactic acid, and thermoplastic starch.

18. The biodegradable paper barrier laminate according to any one of claims 1 to 4, wherein the biodegradable polymer layer comprises at least one water-soluble polymer, the water-soluble polymer being at least one of polyvinyl alcohol, polyethylene oxide, methylcellulose or sodium alginate.

19. The biodegradable paper barrier laminate according to claim 18, wherein the polyvinyl alcohol has an average molecular weight of 20,000 Da to 150,000 Da.

20. The biodegradable paper barrier laminate according to claim 18, wherein the polyvinyl alcohol is a homopolymer having a degree of hydrolysis of 70% to 100%.

21. The biodegradable paper barrier laminate according to claim 20, wherein the polyvinyl alcohol is a homopolymer having a degree of hydrolysis of 84% to 92%.

22. The biodegradable paper barrier laminate according to claim 20, wherein the polyvinyl alcohol is a homopolymer having a degree of hydrolysis of 86% to 90%.

23. A method of preparing the biodegradable paper barrier laminate according to claim 1, comprising: a) applying a second aqueous system of an aqueous biodegradable polymer composition to the surface of a removable flat support; b) removing water from the second aqueous system of the aqueous biodegradable polymer composition to obtain a second biodegradable polymer layer; c) applying an aqueous dispersion of hydrophilic nanosheets onto the outer surface of the second biodegradable polymer layer; d) removing water from said aqueous dispersion of hydrophilic nanoplatelets to obtain a water-dispersible barrier layer; e) applying a first aqueous system of an aqueous biodegradable polymer composition to said inner surface of the biodegradable paper layer; f) bonding said outer surface of said water-dispersible barrier layer to said first aqueous system of a waterborne biodegradable polymer composition; g) removing water from the first aqueous system of the aqueous biodegradable polymer composition to obtain a first biodegradable polymer layer; h) removing the flat carrier from the resulting biodegradable paper barrier laminate.

24. The method of claim 23, wherein the removable flat carrier is a PET film or a steel tape.

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