Barrier System

Abstract

The packaging material has a substrate and an oxygen permeation-inhibiting layer supported by the substrate. The oxygen permeation-inhibiting layer is formed from a composite material including a linear polysaccharide medium having one or more additives dispersed therein. The composite material can form a substantially continuous film for providing a barrier to oxygen gas permeation. The oxygen permeation-inhibiting layer is configured in the packaging material at a thickness effective to inhibit oxygen gas permeation therethrough. The packaging device has two or more component parts, at least one of which is formed from a packaging material. The component parts of the packaging device are shaped and / or configured to assemble and define an interior region into which an item is to be placed.

Description

[Technical Field]

[0001] This invention relates to a barrier system for packaging materials and to packaging materials incorporating the barrier system. The invention also relates to a method for forming packaging materials. [Background technology]

[0002] In this specification, the term “product” means a product whose quality deteriorates over time (i.e., deteriorates, decays, rots, and / or decomposes), and which is most desirable for its intended use if the deterioration is minimal. Therefore, “products” include food and beverages for human or animal consumption; pharmaceuticals, nutraceuticals (also known as “bioceuticals” or “functional foods”), and dietary supplements for human or animal use; cosmetics; and various garden and household products intended for human / animal use but not for ingestion. It should be understood that this is not an exhaustive list of products that constitute “products.”

[0003] Some goods are known to deteriorate in quality when exposed to various fluids, including gases, water vapor, and liquid water in the atmosphere. Minimizing the exposure of such goods to these fluids is a crucial factor in maximizing their shelf life. For these reasons, packaging materials for goods that deteriorate in quality are often formed with barriers that block or inhibit the permeation of fluids that contribute to deterioration (referred to as “hazardous fluids” for the purposes of this application), and thus extend the shelf life of the goods. In this context, two fluids that are generally hazardous to goods are oxygen gas and water vapor. Therefore, the performance of packaging materials (including single materials, blended materials, and laminates) can be characterized by their oxygen permeability ("OTR") and / or water vapor permeability ("WVTR," also known as moisture vapor transmission rate).

[0004] Generally, packaging materials made solely from plastic or containing plastic components are used because they can provide desirable WVTR and OTR barriers, either alone or in combination. The plastics used in packaging materials are mostly petroleum-based and are increasingly considered undesirable due to their unsustainable environmental costs. While bioplastics are well-known, they are also considered undesirable in some jurisdictions due to the challenges and difficulties associated with waste recycling and / or composting / (biodegradation).

[0005] Some plastic materials and metal foils are known to have OTR and / or WVTR values ​​desirable for use as packaging materials. However, in general, for packaging materials, a high rank in terms of OTR value does not necessarily correlate with a high rank in terms of WVTR value, and vice versa. Furthermore, packaging materials for items to be ingested need to be compatible with the items contained within them (so as to mitigate harmful interactions between the items and the packaging material). Therefore, packaging materials are often formed by blending / combining multiple constituent materials (including lamination, co-formation, co-molding, etc.) to achieve desired properties, including oxygen permeability and / or water vapor permeability.

[0006] While some packaging materials are reusable, the recycling process to obtain usable materials involves significant energy, time, and / or material costs. Recycling packaging materials formed from blended materials requires separation into individual components, which increases the complexity of the recycling process to a point where reuse becomes impractical. Therefore, the majority of packaging materials end up in landfills.

[0007] Packaging materials made from biologically generated natural resources are considered sustainable, and therefore desirable, because they can be compostable. However, such packaging materials generally have high WVTR and OTR values, meaning they have poor water vapor and oxygen barrier properties.

[0008] To achieve the desired barrier performance while minimizing the use of petroleum-based materials, it is known to incorporate thin coatings of plastic / bioplastics onto biologically generated, natural resource-derived base materials. However, due to the blended nature of the materials, their recyclability / compostability is compromised.

[0009] Composting biodegradable products is an efficient waste management method, especially in localized waste management practices where waste transportation distances are short. Furthermore, composted materials can be redistributed to agricultural producers instead of being buried in landfills. [Overview of the Initiative]

[0010] It is required to address the above and / or to provide at least a useful alternative. A packaging material is provided comprising a base material and an oxygen permeability inhibiting layer held by the base material and formed from a composite material, wherein the composite material comprises a linear polysaccharide medium in which one or more additives are dispersed, thereby promoting the formation of a substantially continuous film of the composite material that can provide a barrier against the permeation of oxygen gas, the oxygen permeability inhibiting layer being present in the packaging material with a thickness effective in inhibiting the permeation of oxygen gas through it.

[0011] In at least some embodiments, at least one of the additives forms a bond with the linear polysaccharide medium, and this bond contributes to at least one of the formation of a substantially continuous film and elasticity. The bond formed between the linear polysaccharide medium and the additive in the composite material may be a physical bond and / or a covalent bond.

[0012] Preferably, the linear polysaccharide medium is formed by a process comprising at least partially deacetylating a long-chain polymer of an amide derivative of monosaccharide glucose. More preferably, the amide derivative of monosaccharide glucose includes N-acetylglucosamine. In at least some embodiments, the linear polysaccharide medium is formed by a process comprising at least partially deacetylating chitin.

[0013] In certain embodiments, the linear polysaccharide medium is chitosan. The amide derivatives of the monosaccharide glucose may further contain beta-glucan molecules. As an alternative or addition, linear polysaccharide media, which are at least partially deacetylated chitin, may contain beta-glucan molecules. Chitin may be derived from fungi. The fungi may be selected from fungi within the genus Aspergillus and / or fungi within the genus Agaricus. In some examples, chitin is obtained from Aspergillus niger. In some other examples, chitin is obtained from Agaricus bisporus. Chitin may be derived from crustaceans as an alternative or addition. Chitin may be a blend of chitins from different sources.

[0014] In at least some embodiments, the linear polysaccharide medium comprises N-acetylglucosamine. In certain embodiments, the linear polysaccharide medium is chitosan. Chitosan preferably has a low molecular weight. Chitosan may have a molecular weight in the range of 5 to 200 kilodaltons. Preferably, chitosan has a molecular weight in the range of 10 to 100 kilodaltons.

[0015] In some alternative embodiments, the linear polysaccharide medium comprises N-acetylglucosamine dissolved in a solvent. Preferably, the solvent is acidic. The solvent may include water adjusted to an acidic pH by the addition of an inorganic or organic acid. More preferably, the inorganic or organic acid is a carboxylic acid. Even more preferably, the carboxylic acid is one or more of acetic acid, citric acid, lactic acid, malic acid, and tartaric acid.

[0016] In certain cases, the oxygen permeability inhibiting layer is prepared from a solution containing at least one organic compound that acts as a plasticizer during the formation of the oxygen permeability inhibiting layer. The additives in the composite material may include plant-derived compounds. In at least some forms, the plant-derived compounds are in the form of particles, fibers, or a combination thereof. In at least some embodiments, the plant-derived compound is cellulose. In certain embodiments, the cellulose is substantially in the form of fibers. The fibers may be subjected to a refining process that includes longitudinal shearing of the individual fibers. As an alternative or addition, the refining process alters the dimensional properties of the individual fibers.

[0017] Alternatively, or as an addition, the additives may include one or more plasticizers for linear polysaccharide media and / or contribute to the hydrophobicity of the composite material. Preferably, the oxygen permeability inhibiting layer is formed to an average thickness in the range of 7.5 to 60 μm. More preferably, the oxygen permeability inhibiting layer is formed to an average thickness of at least 10 μm. Even more preferably, the oxygen permeability inhibiting layer is formed to an average thickness in the range of 15 to 30 μm. As another option or in more detail, the oxygen permeability inhibiting layer is formed to ensure that the oxygen permeability of the packaging material at 23°C and 50% relative humidity is 6 cubic centimeters per square meter per day (cm 3 / m 2 It is formed on the substrate with a thickness such that the oxygen permeability of the packaging material at 23°C and 50% relative humidity is less than 3 cubic centimeters per square meter per day (cm²). In some embodiments, the oxygen permeability inhibiting layer is formed on the substrate with a thickness such that the oxygen permeability of the packaging material at 23°C and 50% relative humidity is less than 3 cubic centimeters per square meter per day (cm²). 3 / m 2It is formed on the substrate with a thickness such that it is less than

[0018] In at least some embodiments, the packaging material includes at least one intervening material that at least partially separates the composite material of the oxygen transmission inhibiting layer from the substrate. In some embodiments, the intervening material inhibits the transmission of water vapor through the packaging material. As another option or in addition, the intervening material is selected for its ability to bond to the composite material of the oxygen transmission inhibiting layer.

[0019] In at least some embodiments, the intervening material is assembled to form at least one intermediate layer that is between the substrate and the oxygen transmission inhibiting layer and is in contact with one or both of the substrate and the oxygen transmission inhibiting layer. In embodiments where the intervening material is in contact with the substrate, microscopic recesses at the boundary of the substrate and facing towards the oxygen transmission inhibiting layer are substantially filled by the intervening material.

[0020] In certain embodiments, the intervening material is formed with a thickness that forms a continuous layer of material between the substrate and the oxygen transmission inhibiting layer. Preferably, the intervening material is formed with a thickness within the range of 15 - 60 μm. More preferably, the intervening material is formed with a thickness within the range of 30 - 45 μm.

[0021] Preferably, the intervening material is assembled into a first intermediate layer, and the first intermediate layer includes one or more compounds of a first set where at least one is insoluble in water, is solid at standard ambient temperature, and is configured in the packaging material with a thickness effective to inhibit the transmission of water vapor therethrough.

[0022] As another option or preferably, the first set of compounds includes one or more base compounds, and each base compound is an ester of a long - chain alcohol and a fatty acid. Preferably, the base compound includes one or more waxes. The one or more waxes of the first layer are preferably of plant origin.

[0023] In some embodiments, the base compound comprises candelilla wax. In some alternative embodiments, the base compound comprises carnauba wax. As an alternative or addition, the base compound is a blend of two or more waxes.

[0024] The first set of compounds may comprise one or more interfacial energy modifiers that promote increased interlayer adhesion between the first intermediate layer and the oxygen permeability inhibiting layer, and / or promote the formation of the oxygen permeability inhibiting layer on the first intermediate layer during the manufacturing of the packaging material. In some examples, the interfacial energy modifier comprises one or more of the following: a surface-active polymer, an emulsifier, and a surfactant. The interfacial energy modifier may comprise a compound derived from 1,4-anhydrosorbitol, or a mixture of compounds containing 1,4-anhydrosorbitol. More specifically, the interfacial energy modifier comprises a compound derived from sorbitan. In some examples as alternatives, the interfacial energy modifier comprises oleic acid.

[0025] The first set of compounds may contain an interfacial energy modifying additive in a proportion of up to 30% by weight relative to the base compound. In some examples, the material of the first layer may contain an interfacial energy modifying additive in a proportion of up to 8% by weight relative to the base compound.

[0026] As an alternative or addition, the first set of compounds may include particles dispersed within the base compound, which provide a barrier against the permeation of water vapor through the intervening material and / or advantageously modify the adhesion to the substrate or oxygen permeation inhibiting layer.

[0027] The particles dispersed within the base compound may be one or more of the following: primary particles, aggregates, condensates, and crystalline solids. The particles dispersed within the base compound may be primarily nonmetallic compounds.

[0028] In some cases, at least some of the particles dispersed within the base compound are hydrophobic, and therefore the permeation of water vapor through the intervening material is inhibited by this hydrophobicity. In some examples where at least some of the particles dispersed within the base compound are crystalline solids, the crystalline structure of these particles provides a barrier against water vapor permeation.

[0029] The particles dispersed within the base compound may include any of the following: silica-based particles, aluminum-based particles, magnesium-based particles, crystalline boron nitride, and crystalline carbon. In a particular embodiment, the intervening material in the first layer is a mixture of the first set of compounds.

[0030] In some embodiments, the intervening material is further assembled into a second intermediate layer comprising one or more compounds of a second set. The second set of compounds comprises one or more of the compounds in the first set of compounds. The second intermediate layer is located between the first intermediate layer and the oxygen permeability inhibiting layer. The oxygen permeability inhibiting layer is adhered to the second intermediate layer.

[0031] The interfacial energy of the intervening material in the first intermediate layer may be higher than the interfacial energy of the intervening material in the second intermediate layer. Preferably, the second set of compounds comprises all the compounds from the first set, and at least one modifier that, when combined with the compounds from the first set, increases the interfacial energy of the compounds from the first set. In some examples, the second set of compounds is a mixture of the compounds from the first set and the modifier.

[0032] The modifier may contain one or more of the following: polyether compounds, glycols, galacturonic acid, sugar-alcohol derivatives, ozone, and solvents. If present, the polyether compound may contain polyethylene glycol.

[0033] If present, galacturonic acid may be in the form of pectin. If present, the sugar-alcohol derivative compound may be sorbitol or sorbitan.

[0034] The intervening material of the first layer preferably has improved filling properties with respect to the substrate material compared to the filling properties with respect to the composite material when the composite material is applied directly to the substrate material.

[0035] As an alternative or addition, the intervening material of the first layer has improved bonding properties with the substrate material compared to the bonding properties of the composite material when applied directly to the substrate material.

[0036] Preferably, the geometric variation of the material interface profile between the intervening material and the oxygen permeability inhibiting layer is smaller than the geometric variation of the material interface profile between the substrate and the intervening material. Geometric variations are identified from the average value averaged across the entire corresponding material boundary interface profile, and are measured perpendicular to the local tangential plane of the material boundary interface.

[0037] Preferably, the average of the absolute values ​​of the geometric deviations of the interface profile of the material boundary interface profile between the intervening material and the oxygen permeability inhibiting layer is smaller than the average of the absolute values ​​of the geometric deviations of the material boundary interface profile between the substrate and the intervening material. Geometric deviations are measured perpendicular to the local tangent plane of the material boundary.

[0038] In at least some embodiments, the packaging material includes a protective layer assembled into a substantially continuous film to inhibit the interaction between the oxygen permeability inhibiting layer and the atmosphere by providing a barrier between the oxygen permeability inhibiting layer and the atmosphere. The protective layer may be in contact with the oxygen permeability inhibiting layer. As an alternative or additional option, the protective layer may define one face of the packaging material. In some examples, the protective layer may define the outer face of the packaging material. In some examples, as an alternative or additional option, the protective layer may define the inner face of the packaging material.

[0039] In a particular embodiment, the oxygen permeability inhibiting layer is located between the substrate and the protective layer. Preferably, the protective layer inhibits the interaction between the oxygen permeability inhibiting layer and water vapor in the atmosphere. More preferably, the protective layer is hydrophobic.

[0040] The protective layer preferably comprises a polymer material. In some embodiments, the protective layer comprises poly(lactic acid-co-glycolic acid). Poly(lactic acid-co-glycolic acid) can be formed from lactic acid and glycolic acid in a monomer ratio in the range of 40:60 to 85:15. More preferably, poly(lactic acid-co-glycolic acid) can be formed from lactic acid and glycolic acid in a monomer ratio in the range of 50:50 to 75:25. As another option or addition, poly(lactic acid-co-glycolic acid) can be formed from lactic acid and glycolic acid with a larger proportion of lactic acid monomer present during polymerization.

[0041] Preferably, the protective layer is formed to an average thickness in the range of 2.5 to 100 μm. More preferably, the protective layer is formed to an average thickness in the range of 5 to 50 μm. In at least some embodiments, the substrate is formed from pulp fibers that have been assembled and processed to take a predetermined shape, and is treated to form bonds between the pulp fibers within the substrate so that the substrate can at least partially maintain its shape even when unsupported.

[0042] Packaging devices formed from the packaging materials described above are also provided, which are molded and / or configured to define an internal area in which an item will be contained. A packaging device is also provided having two or more component parts, at least one of which is formed from the packaging material described above, wherein the component parts of the packaging device are assembled and molded and / or configured to define an internal area in which an item will be contained.

[0043] The packaging device may be configured such that the substrate is positioned between the oxygen permeability inhibiting layer and the internal region. Alternatively, the packaging device may be configured such that the oxygen permeability inhibiting layer is positioned between the substrate and the internal region.

[0044] In some embodiments, the packaging device is A container portion having a body that defines an internal region and an annular flange that surrounds the entrance to the internal region, A lid portion having a surrounding edge region that seals the internal region by being joined to an annular flange, The container portion and the lid portion are formed separately, and when joined in this manner, they form a capsule that contains the aliquots of the product. At least one of the container portion and the lid portion is formed from the packaging material described above.

[0045] A packaging sheet material formed from the packaging material described above is also provided, and the packaging sheet material is configured to have an outer surface and an inner surface that faces inward with respect to the item packaged using the packaging sheet material.

[0046] The packaging sheet material may be configured such that the base material is positioned between the oxygen permeability-inhibiting layer and the inner surface. Alternatively, the packaging sheet material may be configured such that the base material is positioned between the oxygen permeability-inhibiting layer and the outer surface.

[0047] Preferably, the packaging sheet material has markings on its inner surface and / or outer surface, which allow the inner and outer surfaces of the packaging sheet material to be distinguished. In some embodiments, the packaging sheet material is a flat sheet.

[0048] In some alternative embodiments, the inner surface is non-planar and / or the outer surface is non-planar. The inner and outer surfaces may be molded such that the thickness of the packaging sheet material varies in the length and / or width directions.

[0049] Also, packaging materials, Substrate and A protective layer comprising poly(lactic acid-co-glycolic acid), assembled and held by a substrate, forming a substantially continuous film, defining one side of the packaging material. Packaging materials are also provided, including a protective layer having a thickness effective in inhibiting the interaction between atmospheric water vapor and the packaging material beneath the protective layer.

[0050] Poly(lactic acid-co-glycolic acid) can be formed from lactic acid and glycolic acid in a monomer ratio of approximately 50:50. Alternatively, poly(lactic acid-co-glycolic acid) can be formed from lactic acid and glycolic acid with a larger proportion of lactic acid monomer present during polymerization.

[0051] Preferably, the protective layer is formed to an average thickness in the range of 2.5 to 100 μm. More preferably, the protective layer is formed to an average thickness in the range of 5 to 50 μm. In some cases, the protective layer may define the external surface of the packaging material. In some cases, the protective layer may define the internal surface of the packaging material, either as an alternative or additional option.

[0052] In certain embodiments, the packaging material further includes one or more intermediate layers between the substrate and the protective layer, the intermediate layers being effective in preventing the permeation of at least one of oxygen gas and water vapor through it.

[0053] In at least some embodiments, the substrate is formed from pulp fibers that have been assembled and processed to take a predetermined shape, and is treated to form bonds between the pulp fibers within the substrate so that the substrate can at least partially maintain its shape even when unsupported.

[0054] A method for manufacturing packaging materials is also provided, and the method is as follows: To form a substrate that has a predetermined shape and can maintain that predetermined shape at least partially even when not supported, Applying the first layer to one surface of the substrate, To improve the receptivity of the first layer to bonding, the applied first layer is surface-treated, and Applying a second layer, which is effective in inhibiting the permeation of at least one of oxygen gas and water vapor through it, to the processing surface of the first layer. The surface treatment process includes a step that promotes adhesion of the second layer to the first layer.

[0055] Furthermore, a method for manufacturing packaging materials is provided, and the method is as follows: To form a substrate that has a predetermined shape and can maintain that predetermined shape at least partially even when not supported, Applying the first layer to one surface of the substrate, To remove contaminants from the surface of the applied first layer, the applied first layer is surface-treated, and Applying a second layer, which is effective in inhibiting the permeation of at least one of oxygen gas and water vapor through it, to the processing surface of the first layer. The surface treatment process includes a step that promotes adhesion of the second layer to the first layer.

[0056] Furthermore, a method for manufacturing packaging materials is provided, and the method is as follows: To form a substrate that has a predetermined shape, can maintain that predetermined shape at least partially even when not supported, and has a first surface with a first surface roughness, Applying the first layer to the first surface of the substrate, The first layer to be applied is to be surface-treated such that the applied first layer has a treated surface with a second surface roughness, and Applying the second layer onto the processing surface of the first layer. The second surface roughness is smaller than the first surface roughness.

[0057] Furthermore, a method for manufacturing packaging materials is provided, and the method is as follows: To form a substrate that has a predetermined shape and can maintain that predetermined shape at least partially even when not supported, Applying the first layer to one surface of the substrate, Surface treatment of the applied first layer such that the geometric variation of the treated surface of the first layer is smaller than the geometric variation of the surface of the substrate on which the first layer is formed, and Applying the second layer onto the processing surface of the first layer. The geometric variation is identified from the average plane with respect to the corresponding processing surface / substrate surface, and the geometric variation is measured in a direction either perpendicular or parallel to the local tangent plane intersecting the outer surface of the substrate.

[0058] Furthermore, a method for manufacturing packaging materials is provided, and the method is as follows: To form a substrate that has a predetermined shape and can maintain that predetermined shape at least partially even when not supported, Applying the first layer to one surface of the substrate, Surface treatment of the applied first layer such that the average value of the absolute deviations of the profile height of the treated surface of the first layer is smaller than the average value of the absolute deviations of the profile height of the surface of the substrate on which the first layer is formed, and Applying the second layer onto the processing surface of the first layer. Including this, the profile height deviation is measured in a direction perpendicular to the local tangent plane that intersects the outer surface of the packaging material.

[0059] Furthermore, a method for manufacturing packaging materials is provided, and the method is as follows: To form a substrate that has a predetermined shape and can maintain that predetermined shape at least partially even when not supported, Applying the first layer to one surface of the substrate, To increase the surface energy of the first layer, the applied first layer is surface-treated, and Applying a second layer, which is effective in inhibiting the permeation of at least one of oxygen gas and water vapor through it, to the processing surface of the first layer. The surface treatment process includes facilitating the application of the second layer to form a film of the second layer material on the first layer.

[0060] In some embodiments, the surface treatment step includes applying heat to the exposed surface of the applied first layer. The surface treatment process may include plasma treatment.

[0061] The surface treatment process may include transferring energy from an energy source to the surface of the applied first layer. In some embodiments, the energy source is plasma to impart a change to the surface of the applied first layer. In some alternative embodiments, the energy source is ultraviolet light.

[0062] Another option may involve bringing the exposed surface of the applied first layer into contact with one or more chemicals that interact with the material of the first layer, thereby inducing a change in the properties of the exposed surface.

[0063] In a particular embodiment, the first layer is formed from raw materials containing one or more compounds insoluble in water, the first layer is solid at standard ambient temperature, and the method further... Transferring raw materials onto the surface of a base material in powder form, and Exposing the applied raw materials to heat for a predetermined period of time so that the applied raw materials melt, flow, form a continuous layer on the surface of the substrate, and can subsequently solidify. Includes.

[0064] In some alternative embodiments, the first layer is formed from raw materials containing one or more compounds insoluble in water, the first layer is solid at standard ambient temperature, and the method further... Liquefying the raw materials, Transferring liquefied raw materials onto the surface of a substrate, and Solidifying liquefied raw materials, thereby forming a continuous layer on the surface of the substrate. Includes.

[0065] The process of transferring the liquefied raw material may include spraying the liquefied raw material onto the surface of the substrate. Alternatively, the process of transferring the liquefied raw material may include forming a bath of the liquefied raw material and immersing the substrate in the bath to transfer the raw material onto the surface of the substrate. The process of transferring the liquefied raw material may include supplying the liquefied raw material onto the surface of the substrate in a laminar flow.

[0066] In certain embodiments of the method, the surface treatment step is performed before the solidification of the applied first layer of liquefied raw materials is complete. The process of forming the substrate is: To prepare a slurry of pulp fibers suspended in a liquid, Forming a wet pulp fiber preform on a mold having a shape corresponding to a predetermined shape of the formed substrate, and The process involves treating a wet pulp fiber preform to reduce its moisture content, thereby forming a base material as a molded pulp fiber product. It may include.

[0067] Preferably, the method further, This includes forming a protective layer on the second layer, the protective layer being made of a material that inhibits the interaction between atmospheric water vapor and the second layer in the finished packaging material.

[0068] The step of forming a protective layer may include applying a solution consisting of a solvent and poly(lactic acid-co-glycolic acid) to a second layer, and evaporating the solvent to form a film of the protective layer material.

[0069] The process of forming the protective layer may also include heat-treating the protective layer material to close the pores in the poly(lactic acid-co-glycolic acid). Alternatively, or in addition, the step of forming the protective layer may include controlling the rate of evaporation of the solvent to mitigate the formation of pores in the poly(lactic acid-co-glycolic acid) as the solvent evaporates.

[0070] Next, embodiments of the present invention will be described, merely as examples, with reference to the accompanying drawings, so that the present invention may be more easily understood. [Brief explanation of the drawing]

[0071] [Figure 1] Figure 1 is a perspective view of a packaging device according to one embodiment of the present invention. [Figure 2] Figure 2 is a vertical cross-sectional view of the container portion of the packaging device shown in Figure 1. [Figure 3] Figure 3 is an enlarged view of area A in Figure 2. [Figure 4] Figure 4 is a flowchart of a method for manufacturing a packaging material according to another embodiment of the present invention. [Figure 5] Figure 5 is a schematic diagram of region B in Figure 3, showing a portion of the substrate surface during a stage of the method in Figure 4. [Figure 6] Figure 6 is a chart showing the absolute values ​​of geometric deviations within portion D of the surface shown in Figure 5. [Figure 7] Figure 7 is a schematic diagram of region C in Figure 3, showing a portion of the processing surface of the first layer in a certain stage of the method in Figure 4. [Figure 8] Figure 8 is a chart showing the absolute values ​​of the geometric deviations within the interface portion E shown in Figure 7. [Figure 9]Figure 9 is a horizontal cross-sectional view of the packaging device shown in Figure 1. [Figure 10] Figure 10 is a schematic diagram of region F in Figure 9, showing a portion of the material boundary interface profile between the substrate and the first layer. [Modes for carrying out the invention]

[0072] Figures 1 and 2 show a packaging device 10 according to one embodiment. The packaging device 10 includes two components: a container portion 12 and a lid portion 14. As shown in Figure 2, the container portion 12 is concave to define an internal region 15 in which the goods will be contained. For this purpose, the container portion 12 in this example has an external surface 16 and an internal surface 18. The annular flange 20 surrounds the entrance to the internal region 15. The lid portion 14 similarly has an internal surface (not shown) and an external surface 22. The diameter of the lid portion 14 is the same as the outer diameter of the annular flange 20. In the assembled packaging device 10, the annular flange 20 is joined to the periphery edge region of the lid portion 14.

[0073] In this example, the container portion 12 and the lid portion 14 are each formed from a packaging material according to one embodiment. Figures 3 to 6 show (schematically) details of the packaging material used for the container portion 12, as merely an example.

[0074] Figure 3 shows a cross-section of a portion of the container portion 12, i.e., a cross-section through the packaging material when manufactured in the shape of the container portion 12. Figure 3 shows the outer and inner surfaces 16 and 18, respectively. It is understood that in the finished container portion 12, the outer and inner surfaces 16 and 18, respectively, are exposed to the surrounding environment. The terms “inner surface” and “outer surface” apply to the orientation of the corresponding surfaces 16 and 18, taking into account the internal region 15 of the packaging device 10.

[0075] The packaging material includes a base material 50, which in this example is in the form of a molded pulp fiber product. With respect to the container portion 12, the finished article will have specific geometric and shape characteristics. While these geometric and shape characteristics are specific to the article, it is understood that they depend on the article and its intended use, rather than on the present invention. Also with respect to the container portion 12, the base material 50 is formed so that it can maintain its molded shape even when unsupported. In some alternative embodiments, the base material (or the material forming the base material) may not have the ability to maintain its shape when unsupported.

[0076] In this particular embodiment, the substrate 50 has a first layer 52, a second layer 54, and a third layer 56. As shown in Figure 3, the exposed surface of the substrate 50 is the outer surface 16, and the exposed surface of the third layer 56 is the inner surface 18 of the container portion 12. As will be described in more detail below, each of the layers 52, 54, and 56 is a functional layer that contributes in one or more ways to inhibit the permeation of atmospheric fluids surrounding the packaging material through the packaging material. In this way, the layers 52, 54, and 56 provide an increased barrier against the permeation of one or more fluids through the packaging material compared to the substrate 50 alone. In the example of the packaging device 10, it is understood that this increased barrier makes it possible to extend the shelf life of the goods stored inside the container portion 12 and sealed by joining the lid portion 14 to the container portion 12.

[0077] Within the packaging material, there is a first interface 58 formed at the material boundary between the base material 50 and the first layer 52, and a second interface 62 formed at the material boundary between the first and second layers 52 and 54. Further interfaces are also formed at the material boundaries of the second and third layers 54 and 56. In Figure 3, the material boundary interfaces are represented by lines, but it is understood that these interfaces are three-dimensional within the physical packaging material of the embodiment.

[0078] The first layer 52 is formed from an intervening material containing a compound insoluble in water. Furthermore, the first layer 52 is solid at standard ambient temperatures. In this particular example, the first layer 52 is formed of a material and thickness that is effective in inhibiting the permeation of water vapor through it.

[0079] Throughout this specification and the subsequent claims, references to “standard ambient temperature” should be understood to mean 25°C (77°F), in accordance with the definition of standard ambient temperature and pressure (SATP) as defined by the International Union of Pure and Applied Chemistry (IUPAC).

[0080] For example, the first layer 52 may be formed from carnauba wax, candelilla wax, or a blend thereof. The raw materials for the first layer 52 are applied to the substrate 50 so that a continuous layer is formed throughout the substrate 50.

[0081] Before applying the second layer 54 to the first layer 52, the first layer 52 is subjected to a surface treatment process. The surface treatment process alters the properties of the applied surface of the first layer 52 that define the second interface 62 between the first and second layers 52, 54 in the finished packaging material. For this purpose, the surface treatment process - The receptivity of the first layer 52 to the adhesion of the second layer 54 can be improved. - To promote adhesion to the first layer 52, contaminants on the surface of the applied first layer 52 can be removed, and / or - The surface energy of the first layer 52 can be increased.

[0082] Throughout this specification and the subsequent claims, unless otherwise required by context, the terms “surface energy” and “interface energy” should be understood to have the same meaning. Furthermore, the term “surface energy” does not imply that the corresponding material boundary is exposed to the atmosphere.

[0083] In some examples, the surface treatment process can alter the geometric properties of the applied first layer 52 so as to reduce the surface roughness before applying the material that forms the second layer 54.

[0084] As can be seen from Figure 3, the material of the first layer 52 is placed between the substrate 50 and the second layer 54. The second layer 54 is formed from a composite material containing an additive dispersed in a linear polysaccharide medium. The additive forms bonds with the linear polysaccharide medium, thereby promoting the formation of a substantially continuous film that can provide a barrier against oxygen gas permeation. The bonds between the linear polysaccharide medium and the additive may be physical bonds and / or covalent bonds. Furthermore, the second layer 54 is formed in the packaging material with a thickness effective in inhibiting oxygen gas permeation through it. In this way, the second layer 54 provides a barrier against oxygen gas permeation in the packaging material.

[0085] For example, the linear polysaccharide medium is low molecular weight chitosan, and the additive may include fibers. The fibers may consist of or contain cellulose fibers. The composite material may be prepared in solution to facilitate application to the first layer 52. The solvent may be water and / or other organic / inorganic compounds that are liquid at room temperature. If the solvent contains water and one or more other compounds, these other compounds are, ideally, very miscible with water, if not completely miscible.

[0086] The solution is transferred to the exposed surface of the first layer 52 using a known liquid application method. Surface treatment of the first layer 52 facilitates the dispersion of the solution. By evaporating the solvent, the uniformly dispersed chitosan and cellulose fibers remain on the first layer 52, forming a film. The cellulose fibers in the film support the internal stress in the chitosan film, at least during the process of solvent evaporation. Alternatively, or in addition, a more elastic film may be formed.

[0087] As can be understood, in this particular embodiment, the first layer 52 facilitates the dispersion of the solution containing the material for the second layer during the process of forming the second layer 54. In the example shown in Figure 1, the protective layer 56 forms the inner surface 18 of the packaging material and is also in contact with the second layer 54. The protective layer 56 is assembled into a substantially continuous film that provides a barrier between the second layer 54 and the atmosphere.

[0088] The protective layer 56 forms a barrier against water vapor and thus inhibits the interaction between the material of the second layer 54 and water vapor in the atmosphere. The presence of the protective layer 56 reduces damage to the chitosan film of the second layer 54 by water vapor in the atmosphere.

[0089] In this embodiment, the protective layer comprises a polymer material. In some embodiments, the protective layer comprises poly(lactic acid-co-glycolic acid), which is generally collectively referred to as PLGA. PLGA can be formed from lactic acid and glycolic acid in a monomer ratio of approximately 50:50.

[0090] Figure 4 is a flowchart of the method 100 for manufacturing packaging material according to the second embodiment. Referring to the elements of the packaging material shown in Figure 3, Method 100 is: - Step 102 to form a base material 50 having a first surface, - Step 104: Applying the first layer 52 to the first surface of the substrate 50. - Step 106 of surface treatment of the applied first layer 52, - Step 108 of applying the second layer 54 onto the processing surface of the first layer 52, and - Step 110: Forming a protective layer 56 on the second layer 54. Includes.

[0091] Figure 5 shows an enlarged schematic diagram of the substrate 50 in area B of Figure 3, after step 102 of method 100 is completed but before step 104 is started. The substrate 50 has a first surface at the completion of step 102, on which the first layer 52 will be applied during the process of step 104. The substrate 50 is formed by a process that allows the substrate 50 to maintain a predetermined shape at least partially during the subsequent steps of method 100. In the example of the container portion 12, the substrate 50 is non-planar. In the example of the lid portion 14, the substrate is substantially a planar sheet.

[0092] In Figure 5, the block arrow 18 indicates the direction toward the portion that will ultimately become the inner surface 18 of the packaging material upon completion. In a subsequent step of Method 100, it is understood that the first surface becomes the first internal interface 58 between the substrate 50 and the first layer 52. In Figure 5, the substrate 50 is shown (schematically) in a vertical cross-section, with the first surface indicated by a line. For simplicity in the following description of Figure 5, the first surface is denoted by reference numeral 58.

[0093] Figure 5 shows microscopic geometric variations present on the first surface 58 of the substrate 50. These microscopic geometric variations form peaks and valleys that define the surface roughness of the first surface 58. Furthermore, the peaks and valleys have heights that can be measured in a direction perpendicular to a planar or non-planar reference plane. This reference plane may be the ideal surface of the actual first surface 58, another surface, or a reference plane. In relation to the peaks, the valleys form microscopic depressions on the surface 58 of the substrate 50.

[0094] The first surface 58 has a virtual mean surface 60 which is the arithmetic mean of the heights of the peaks and valleys within the first surface 58 along the direction of measurement. The virtual mean surface 60 has a height from the reference surface, and it is the arrow 60 AVG This is shown in Figure 5. For the sake of clarity, in Figure 5, the reference plane is the tangent plane that intersects the interior surface 18.

[0095] Each point on the first surface 58 has a height relative to the reference surface. Further, each point on the first surface 58 has a profile height deviation from the virtual average surface 60. The profile height deviation can be represented by the following equation, P a =S AVG -H a wherein, P a is the profile height deviation at point a, S AVG is the height of the virtual average surface at point a relative to the reference surface along the measurement direction, H a is the height of point a relative to the reference surface.

[0096] As can be understood from FIG. 5, points a1 and a3 are between the virtual average surface and the reference surface, and thus the profile height deviations for these points are less than zero. The material of the first layer 52 has the ability to flow during the process of being applied onto the substrate 50. Thus, during the process of step 104, the material of the first layer 52 can flow on the first surface 58 and fill the valleys within the range of the geometric variations present on the first surface. The ability of any material in its liquid state to fill valleys within the range of geometric variations of another surface is herein referred to as the "filling property" of that liquid material. As the material of the first layer 52 cures, a bond is formed between the first layer 52 and the substrate 50. The ability of any curable material to form a bond with another material is herein referred to as the "bonding property" of that curable material.

[0097] The material of the first layer 52 has a greater ability to fill and bond on the substrate 50 compared to the ability of the material of the second layer 54 to directly fill and bond on the substrate 50. FIG. 7 shows an enlarged schematic view of the first layer 52 within region C of FIG. 3 after the completion of step 106 of method 100 but before the start of step 108. Thus, the exposed surface of the first layer 52 (far from the substrate 50) is the surface that has been processed during the process of step 106, i.e., the "processed surface".

[0098] In a subsequent step of method 100, it is understood that the processing surface becomes the second internal interface 62 between the first and second layers 52, 54. In Figure 7, the first layer 52 is shown (schematically) in a vertical cross-section, with the processing surface indicated by a line. For simplicity in the following description of Figure 7, the processing surface is denoted by reference numeral 62.

[0099] Figure 7 shows the microscopic geometric variations present on the treated surface 62 of the first layer 52. These microscopic geometric variations form peaks and valleys that determine the surface roughness of the treated surface 62. In relation to the peaks, the valleys form microscopic depressions on the treated surface 62.

[0100] The processing surface 62 also has a hypothetical mean surface 64, which is the arithmetic mean of the heights of the peaks and valleys within the processing surface 62 along the measurement direction. Each point on the processing surface 62 has a height relative to a reference plane, which in this example is also a tangent plane intersecting the interior surface 18.

[0101] Although schematic, Figures 5 and 7 illustrate the difference in the magnitude and period of geometric variation between the first surface 58 and the processing surface 62. In this example, the peak and valley heights on the processing surface 62 are smaller than those on the first surface 58. Therefore, when measured perpendicular to the reference surface, the geometric variation of the processing surface 62 is smaller than that of the first surface 58 (before application of the first layer 52).

[0102] Similarly, in this example, the lateral separation of adjacent peaks on the processed surface 62 is smaller than the lateral separation of adjacent peaks on the first surface 58, along each measurement direction. Therefore, when measured in a direction parallel to the reference plane, the geometric variation of the processed surface 62 is smaller than the geometric variation of the first surface 58 (before application of the first layer 52).

[0103] Figure 6 is a schematic chart showing the absolute values ​​of the profile height deviation within portion D of the first surface 58 shown in Figure 5. In Figure 6, the absolute values ​​of the profile height deviation with respect to a point on the first surface 58 are plotted along the dashed line 58. M This is shown. Points on the horizontal axis are the points where the first plane 58 coincides with the hypothetical average plane 60. On the chart in Figure 5, the absolute value of the profile height deviation is shown, and therefore plot line 58 M This can be expressed by the following equation: P abs =|S AVG -H a | During the ceremony, P abs This is the absolute value of the profile height deviation at point a, S AVG This is the height of the imaginary average plane at point a, relative to the reference plane along the measurement direction. H a This is the height of point a relative to the reference plane.

[0104] Figure 6 also shows the absolute value P of the profile height deviation. abs The average value is 58 H It also shows. Figure 8 is a schematic chart showing the absolute values ​​of the profile height deviation within portion E of the processing surface 62 shown in Figure 7. In Figure 8, the absolute values ​​of the profile height deviation with respect to a point on the processing surface 62 are plotted as shown by the dashed line 62. M This is shown in Figure 8. Figure 8 also shows the absolute value P of the profile height deviation. abs The average value is 62 H It also shows.

[0105] As already mentioned, the surface treatment of the exposed surface of the first layer 52 in step 106 has the beneficial effect of increasing the surface energy of the first layer 52 (compared to the surface energy of the first layer 52 in the untreated state). Subsequently, the increased surface energy promotes the dispersion of the solution that forms the second layer 52 in the process of step 108. Thus, at the end of step 108, the second layer 52 can be uniformly distributed on the first layer 52, thereby forming a film of material that inhibits the permeation of oxygen through it.

[0106] Although schematic, the charts in Figures 6 and 8 show an average value of 58. H (Absolute value P of profile height deviation relative to the first surface 58) abs The average value of the average value is 62 H (Absolute value P of profile height deviation relative to processing surface 62) abs This indicates that it is smaller than the average value. Figure 10 is a magnified schematic diagram of the internal region of the packaging material in region F of Figure 9, showing the base material 50, the first layer 52, and a portion of the material boundary interface 58 between them. Within region F, the outer and inner surfaces 16 and 18 of the container portion 12 are both arc-shaped.

[0107] Figure 10 schematically shows the geometric variation at the interface 58 between the substrate 50 and the first layer 52 within region F of Figure 9, where the geometric variation exists at a microscopic level. Within region F, the container portion 12 differs in that the packaging material is curved. Therefore, the outer and inner surfaces 16 and 18 are curved.

[0108] As shown in Figure 10, the heights of the peaks and valleys formed by these microscopic geometric variations at the material boundary interface 58 have heights measured perpendicular to a local tangent plane that coincides with the reference plane. However, in this part of the container portion 12, the reference plane is non-planar. Therefore, as shown in Figure 10, in this part of the container portion 12, the virtual mean plane 60 (shown as a dashed line) is also non-planar.

[0109] Examples The following description contains, but is not limited to, examples of packaging materials and manufacturing procedures for these packaging materials constructed by the applicant for evaluation purposes. For simplicity, the terminology for packaging materials described with reference to Figure 3 will be used throughout the following description.

[0110] In one example, a molded pulp fiber base was formed from a slurry of pulped bagasse fibers according to a known thermoforming process. An intervening material was applied to one surface of the substrate. For this purpose, a first set of compounds was formed in a heat "bath" (i.e., a reservoir) of liquid material. The first set of compounds contained candelilla wax as an additive. - A surfactant in the form of sorbitol monooleate ester in a ratio of 1% to 5% by weight relative to the wax, and - Fumed silica in a ratio of 0.5% to 2% by weight relative to the wax. It included these together.

[0111] The liquid material was heated to 100°C in a heat bath and mixed so that the additive was dispersed throughout the liquefied wax. The liquid material was applied to one surface of a molded pulp fiber substrate to obtain a film thickness on the order of 30-45 μm. The first set of compounds was allowed to cool and solidify on the substrate. Thus, the first layer was applied to the surface of the substrate.

[0112] The applied first layer was subjected to surface treatment. In some examples, the surface treatment step of the applied first layer included chemical treatment of the exposed surface of the applied first layer to induce a change in the properties of the exposed surface. This chemical treatment included contacting the exposed surface of the applied first layer with one or more compounds.

[0113] In some trials, it has been observed that chemical treatment induces structural changes in the sublayer at the boundary of the exposed surface. In some other trials, it has been observed that chemical treatment triggers a chemical reaction between the material of the first layer and the chemical substance, thereby creating a sublayer within the material of the first layer adjacent to the exposed surface.

[0114] In some trials, the chemical treatment involved depositing additional intervening material, in the form of a modifier, onto the surface of the first layer to which it was applied. In some examples, a modifier was used to form a mixture with a first set of compounds at the boundary region of the applied first layer. In these examples, the applied first layer below the boundary region was maintained, and the mixture of the first and second sets of compounds within that boundary region formed a second intermediate layer. Thus, the second intermediate layer contained the first set of compounds and the modifier. The unaltered intervening material of the applied first layer was maintained below the second intermediate layer, thus establishing a hypothetical first intermediate layer.

[0115] In some other examples, the modifier was a separate second set of compounds that had minimal interaction with the first set of compounds. The trial used chemicals containing ozone gas, dissolved pectin, and dissolved polyether compounds (including polyethylene glycol). Furthermore, the chemical solution used water and volatile liquids as solvents, so that the liquid portion could be evaporated during the surface treatment process.

[0116] A mixture of composite materials for the second layer was formed. For this purpose, a preliminary solution was prepared by mixing powdered chitosan with a molecular weight of 10–100 kDa with an acidic solvent in a ratio within the range of 3–10% by weight of chitosan. In this example, the acidic solvent consisted of deionized water acidified with a mild organic acid having an intensity on the order of 2.5–5.5 pKa.

[0117] In several trials, plasticizers were incorporated into the preliminary solution at a ratio of 1% to 5% by weight. Several plasticizers, including citrate esters, were tested. A secondary solution of refined bagasse fibers and deionized water was formed and subsequently mixed with an acidic solvent. The secondary solution of refined bagasse fibers and deionized water contained approximately 5% by weight of fibers. The secondary solution was added to the preliminary solution in a ratio ranging from 15% to 35%. The combined preliminary solution and secondary solution were mixed to obtain a chitosan-to-fiber ratio ranging from 2:1 to 4.5:1 by dry weight. Next, the composite material for the second layer was mixed at a raised temperature (approximately 40°C) for a long period of time to obtain a composite material in a substantially uniformly distributed dissolved state, and then transferred to a bath.

[0118] At this point, the workpiece, consisting of the substrate and the first and second intermediate layers formed thereon, was immersed in a bath containing the composite material to coat the first layer. Next, the composite material was exposed to infrared light energy while the liquid components evaporated to form a film. The composite material mixture was applied in an amount sufficient to form a film with a thickness on the order of 15–30 μm.

[0119] A mixture of materials for the third layer was formed in a bath. The mixture contained poly(lactic acid-co-glycolic acid), in which the ratio of lactic acid to glycolic acid was on the order of approximately 50:50, dispersed in acetone solvent at a ratio of 5% to 20% by weight. The PLGA component had a molecular weight of 5 to 150 kDa.

[0120] At this point, the workpiece, consisting of the substrate and the formed first and second layers, was immersed in a bath containing the material for the third layer to coat it with the second layer. Next, the workpiece was transferred to an oven heated to a temperature above the glass transition temperature of the PLGA component. The workpiece was maintained at the elevated temperature while the solvent evaporated, during which time the PLGA component hardened to a suitable degree and a film was formed. A mixture of materials for the third layer was applied in an amount sufficient to form a film with a thickness of the order of 5-50 μm.

[0121] After removing the workpiece from the oven, it was allowed to cool to room temperature to complete the manufacturing of the packaging material. Next, the packaging material was analyzed and evaluated. It is understood that the ranges used in the embodiments and examples described herein can be selected in various combinations to obtain different desired properties of water vapor transmission rate and oxygen transmission rate (WVTR and OTR).

[0122] Throughout this specification and the subsequent claims, unless otherwise required by context, the word “comprise,” and variations such as “comprises” and “comprising,” shall be understood to imply that they include, but not any, any other integers or processes, or groups of integers or processes.

[0123] No reference in this specification to any prior publication (or information derived therefrom), or to any known matter, constitutes, acknowledges, or suggests in any way that such prior publication (or information derived therefrom) or known matter forms part of the common general knowledge within the scope of the relevant endeavor, and should not be construed as such.

Claims

1. 1. A packaging material comprising: A substrate; a protective layer comprising poly(lactic-co-glycolic acid) assembled into a substantially continuous film held by the substrate and defining one side of the packaging material; wherein the protective layer has a thickness effective to inhibit interaction of atmospheric water vapor with the packaging material underlying the protective layer.

2. 2. The packaging material of claim 1, wherein the poly(lactic-co-glycolic acid) is formed from lactic acid and glycolic acid with a greater proportion of lactic acid monomer present during polymerization.

3. The packaging material according to claim 1 or 2, wherein the protective layer is formed to an average thickness within a range of 2.5 to 100 μm.

4. Further comprising one or more intermediate layers between the substrate and the protective layer; 4. The packaging material of claim 1, wherein the intermediate layer is effective to inhibit the transmission of at least one of oxygen gas and water vapor therethrough.

5. 5. The packaging material of claim 1, wherein the substrate is formed from pulp fibers that have been assembled and processed to form a predetermined shape and have been treated to form bonds between the pulp fibers within the substrate, thereby enabling the substrate to at least partially maintain its shape when unsupported.

6. A packaging device having two or more constituent parts, at least one of which is formed from the packaging material of any one of claims 1 to 5, said packaging device being shaped and / or configured to be assembled to define an interior area into which an item is to be contained, the protective layer defines one side of the interior region; Packaging device.

7. 7. The packaging material of claim 1, further comprising at least one intervening material in contact with the substrate, the intervening material inhibits the transmission of water vapor through the packaging material; packaging materials.

8. The packaging material of claim 7 , wherein the intervening material is formed at a thickness that forms a continuous layer on the substrate.

9. The intermediate material is a first set of one or more compounds, at least one of which is insoluble in water; It is a solid at standard ambient temperature, and configured in said packaging material at a thickness effective to inhibit the transmission of water vapor therethrough; 9. The packaging material according to claim 7 or 8.

10. 10. The packaging material of claim 9, wherein the first set of compounds comprises one or more base compounds, each base compound being an ester of a long chain alcohol and a fatty acid.

11. The packaging material of claim 10 , wherein the base compound comprises one or more waxes.

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