Film Material

Abstract

The film material is a blend of a first polymer and a second polymer. The first polymer is synthesized from one or more bio-based monomers and has a molecular weight of 60 kilodaltons or less. The second polymer is one of a carbohydrate and a functionalized carbohydrate derived from one or more bio-based materials. The ratio of the first polymer to the second polymer in the film material is at least 25:75 by weight. The packaging material has a substrate and a layer formed from the film material and assembled into a substantially continuous film on a support surface of the substrate. The layer is formed to a thickness effective to provide a barrier against the transmission of oxygen and / or water vapor to the support surface of the substrate.

Description

[Technical field]

[0001] The present invention relates to a film material for use in packaging, to packaging materials incorporating the film material, and to a method of forming the film material. [Background technology]

[0002] There is an increasing demand for bio-based and biodegradable materials suitable for use in product packaging, driven, at least in part, by increased awareness of the sustainability issues of synthetic polymers linked to the availability of raw materials (including crude oil, natural gas, and coal) for their synthesis, and the end-of-life issues of these synthetic polymers.

[0003] Some synthetic polymers, such as polyethylene (PE), polyethylene terephthalate (PET), and polypropylene (PP), have desirable properties for commodity packaging. These properties include low permeability to oxygen gas and / or water vapor, high strength, and durability. These properties are beneficial to manufacturers and supply chains of consumables, and to end users of consumables packaged in packaging materials made from or with synthetic polymers, and many of these benefits relate to the shelf life of the packaged consumables.

[0004] Known bio-based polymers are poorly suited for use in product packaging, especially where low oxygen transmission rate ("OTR") and / or low water vapor transmission rate ("WVTR", also known as Moisture Vapour Transmission Rate) are required. For example, polylactic acid (PLA) is brittle, picks up water easily, and has poor barrier properties against oxygen and water vapor transmission. Polyglycolic acid (PGA) has better barrier properties and is stronger than PLA, but degrades faster. Summary of the Invention

[0005] There is a need for bio-based polymers that can be formed into film materials and thereby are suitable for use in packaging of consumable products and / or at least provide a useful alternative. A film material comprising: a first polymer synthesized from one or more bio-based monomers and having a molecular weight of 60 kilodaltons or less; a second polymer, the second polymer being one of one or more biobased derived carbohydrates and functionalized carbohydrates; wherein the ratio of the first polymer to the second polymer in the film material is at least 25:75 by weight.

[0006] Preferably, the first polymer has a molecular weight of 30 kilodaltons or less. More preferably, the first polymer has a molecular weight of 15 kilodaltons or less. Even more preferably, the first polymer has a molecular weight in the range of 4 kilodaltons to 8 kilodaltons. Even more preferably, the first polymer has a molecular weight in the range of 4.5 kilodaltons to 7.5 kilodaltons. In certain embodiments, the first polymer has a molecular weight of approximately 5.6 kilodaltons.

[0007] In some examples, the first polymer has a polydispersity index of 3 or less. In more particular examples, the first polymer has a polydispersity index of 2 or less. In even more particular examples, the first polymer has a polydispersity index that is in the range of 1.35 to 1.75. In certain examples, the first polymer has a polydispersity index that is in the range of 1.5 to 1.6.

[0008] Preferably, the ratio of the first polymer to the second polymer in the film material is within the range of 80:20 to 10:90 by weight. More preferably, the ratio of the first polymer to the second polymer in the film material is within the range of 75:25 to 25:75 by weight. Even more preferably, the ratio of the first polymer to the second polymer in the film material is approximately 50:50 by weight.

[0009] In certain embodiments, the first polymer is a polyester, a polyvinyl ester, a polyvinyl ester derivative, or a polyether, or a combination thereof. In embodiments where the first polymer comprises a polyester, the polyester is synthesized from one or more of the following monomers: lactic acid, glycolic acid, cyclic ester, butanediol. More preferably, the first polymer comprises one or more of poly(lactic acid) (PLA), poly(lactic acid-co-glycolic acid) (PLGA), polyglycolic acid (PGA), poly(caprolactone) (PCL), poly(butylene adipate terephthalate) (PBAT), poly(butylene succinate) (PBS), and poly(butylene succinate-co-butylene adipate) (PBSA). In embodiments where the first polymer comprises a copolymer, the copolymer may be in the form of an alternating copolymer or as a segment of a block copolymer.

[0010] In embodiments where the first polymer comprises a polyester produced by bacterial fermentation, the first polymer comprises one or more of polyhydroxyalkanoate (PHA) and polyhydroxybutyrate (PHB).

[0011] In embodiments where the first polymer comprises a polyvinyl ester or a polyvinyl ester derivative, the first polymer comprises one or more of poly(vinyl acetate) (PVAc) and poly(vinyl alcohol) (PVOH).

[0012] In embodiments where the first polymer comprises a polyether made from a glycol, the first polymer comprises polyethylene glycol (PEG). Preferably, the first polymer is an aliphatic polyester. Examples of preferred polyesters include, for example, poly(lactic acid), poly(glycolic acid), copolymers of lactic acid and glycolic acid, copolymers of lactic acid, glycolic acid, and poly(ethylene glycol), poly(e-caprolactone), and poly(3-hydroxybutyrate).

[0013] In a particularly preferred embodiment, the first polymer is synthesized from monomers of lactic acid and glycolic acid. Preferably, the first polymer is poly(lactic-co-glycolic acid) (PLGA).

[0014] Poly(lactic-co-glycolic acid) may be formed from lactic acid and glycolic acid in a monomer ratio ranging from 40:60 to 85:15. More preferably, poly(lactic-co-glycolic acid) may be formed from lactic acid and glycolic acid in a monomer ratio ranging from 50:50 to 75:25. In at least some embodiments, poly(lactic-co-glycolic acid) is formed such that the ratio of lactic acid units to glycolic acid units is approximately 60:40. That is, poly(lactic-co-glycolic acid), PLGA, is composed of 60% lactic acid units and 40% glycolic acid units.

[0015] Alternatively or additionally, poly(lactic-co-glycolic acid) can be formed from lactic acid and glycolic acid, with approximately equal ratios of lactic and glycolic acid monomers present during polymerization.

[0016] In some examples, the poly(lactic-co-glycolic acid) is predominantly amorphous. In some alternative examples, the poly(lactic-co-glycolic acid) has a crystallinity of 90% or less. The poly(lactic-co-glycolic acid) may have a crystallinity of 30% to 45%.

[0017] Preferably, the poly(lactic-co-glycolic acid) is formed using lactic acid monomers in which both L and D isomers are present upon polymerization. In certain embodiments, the second polymer is cellulose, a cellulose derivative, an alpha glucan, an alpha glucan derivative, a natural polysaccharide (including those derived from algae and those containing amides), or a combination thereof.

[0018] In embodiments in which the second polymer comprises cellulose, the cellulose can be one or more of cellulose, acetylated cellulose derivatives, nitrated cellulose derivatives, alkylated cellulose derivatives, and hemicellulose.

[0019] Preferably, the second polymer is an acetylated cellulose derivative. The acetylated cellulose derivative is one or more of cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate. In certain embodiments, the acetylated cellulose derivative is cellulose acetate.

[0020] In some embodiments, the cellulose acetate has a degree of acetylation in the range of 1 to 3. In some applications of film materials, the cellulose acetate has a degree of acetylation of at least 2. In some applications, an acetylation degree of approximately 2.5 may be desirable. In some alternative applications of film materials, the cellulose acetate has a degree of acetylation of less than 2.

[0021] The film material may include one or more additives to modify one or more of the oxygen transmission rate through the film material, the water vapor transmission rate through the film material, the reduction in brittleness of the film material, the glass transition temperature of the film material, the hydrophobicity, the surface energy of the film material, and the plasticity of the film material.

[0022] Non-limiting examples of additives include mineral and organic particles (such as talc, mica, clay, silica, alumina, carbon fiber, carbon black, glass fiber, rock fiber, etc.), natural and processed cellulosic materials (such as bagasse, wood, flax, hemp, grass, and grain stalk fibers, as well as fruit, seed, and grain hulls, kenaf, jute, sisal, peanut shells, and other cellulose-containing materials), waxes, natural polysaccharides (including chitin and chitosan), alpha glucans (including starch and pectin). The amount of additive in the blend can vary depending on the desired physical properties of the polymer matrix and the finished composition.

[0023] A film material comprising: a first polymer synthesized from one or more bio-based monomers and having a molecular weight of 60 kilodaltons or less; a second polymer, the second polymer being one of one or more biobased derived carbohydrates and functionalized carbohydrates; wherein the first and second polymers together form a continuous film.

[0024] In certain embodiments, at least a surface layer of a continuous film is formed with a second polymer disposed as a substantially continuous matrix surrounding regions of a first polymer, where within the surface layer, the regions of the first polymer may be of various sizes and / or spacing.

[0025] In some alternative embodiments, at least a surface layer of the continuous film is formed from a first polymer at least partially dispersed in a matrix of a second polymer.

[0026] Preferably, the first polymer has a molecular weight of 30 kilodaltons or less. More preferably, the first polymer has a molecular weight of 15 kilodaltons or less. Even more preferably, the first polymer has a molecular weight in the range of 4 kilodaltons to 8 kilodaltons. Even more preferably, the first polymer has a molecular weight in the range of 4.5 kilodaltons to 7.5 kilodaltons. In certain embodiments, the first polymer has a molecular weight of approximately 5.6 kilodaltons.

[0027] In some examples, the first polymer has a polydispersity index of 3 or less. In more particular examples, the first polymer has a polydispersity index of 2 or less. In even more particular examples, the first polymer has a polydispersity index that is in the range of 1.35 to 1.75. In certain examples, the first polymer has a polydispersity index that is in the range of 1.5 to 1.6.

[0028] Preferably, the ratio of the first polymer to the second polymer in the film material is within the range of 80:20 to 10:90 by weight. More preferably, the ratio of the first polymer to the second polymer in the film material is within the range of 75:25 to 25:75 by weight. Even more preferably, the ratio of the first polymer to the second polymer in the film material is approximately 50:50 by weight.

[0029] In certain embodiments, the first polymer is a polyester, a polyvinyl ester, a polyvinyl ester derivative, or a polyether, or a combination thereof. In embodiments where the first polymer comprises a polyester, the polyester is synthesized from one or more of the following monomers: lactic acid, glycolic acid, cyclic ester, butanediol. More preferably, the first polymer comprises one or more of poly(lactic acid) (PLA), poly(lactic acid-co-glycolic acid) (PLGA), polyglycolic acid (PGA), poly(caprolactone) (PCL), poly(butylene adipate terephthalate) (PBAT), poly(butylene succinate) (PBS), and poly(butylene succinate-co-butylene adipate) (PBSA). In embodiments where the first polymer comprises a copolymer, the copolymer may be in the form of an alternating copolymer, a random copolymer, or as a segment of a block copolymer.

[0030] In embodiments where the first polymer comprises a polyester produced by bacterial fermentation, the first polymer comprises one or more of polyhydroxyalkanoate (PHA) and polyhydroxybutyrate (PHB).

[0031] In embodiments where the first polymer comprises a polyvinyl ester or a polyvinyl ester derivative, the first polymer comprises one or more of poly(vinyl acetate) (PVAc) and poly(vinyl alcohol) (PVOH).

[0032] In embodiments where the first polymer comprises a polyether made from a glycol, the first polymer comprises polyethylene glycol (PEG). Preferably, the first polymer is an aliphatic polyester. Examples of preferred polyesters include, for example, poly(lactic acid), poly(glycolic acid), copolymers of lactic acid and glycolic acid, copolymers of lactic acid, glycolic acid, and poly(ethylene glycol), poly(e-caprolactone), and poly(3-hydroxybutyrate).

[0033] In a particularly preferred embodiment, the first polymer is synthesized from monomers of lactic acid and glycolic acid. Preferably, the first polymer is poly(lactic-co-glycolic acid) (PLGA).

[0034] Poly(lactic-co-glycolic acid) may be formed from lactic acid and glycolic acid in a monomer ratio ranging from 40:60 to 85:15. More preferably, poly(lactic-co-glycolic acid) may be formed from lactic acid and glycolic acid in a monomer ratio ranging from 50:50 to 75:25. In at least some embodiments, poly(lactic-co-glycolic acid) is formed such that the ratio of lactic acid units to glycolic acid units is approximately 60:40. That is, poly(lactic-co-glycolic acid), PLGA, is composed of 60% lactic acid units and 40% glycolic acid units.

[0035] Alternatively or additionally, poly(lactic-co-glycolic acid) can be formed from lactic acid and glycolic acid, with approximately equal ratios of lactic and glycolic acid monomers present during polymerization.

[0036] In some examples, the poly(lactic-co-glycolic acid) is predominantly amorphous. In some alternative examples, the poly(lactic-co-glycolic acid) has a crystallinity of 90% or less. The poly(lactic-co-glycolic acid) may have a crystallinity of 30% to 45%.

[0037] Preferably, the poly(lactic-co-glycolic acid) is formed using lactic acid monomers in which both L and D isomers are present during polymerization. In certain embodiments, the second polymer is cellulose, a cellulose derivative, an alpha glucan, an alpha glucan derivative, a natural polysaccharide (including those derived from algae and those containing amides), or a combination thereof.

[0038] In embodiments in which the second polymer comprises cellulose, the cellulose can be one or more of cellulose, acetylated cellulose derivatives, nitrated cellulose derivatives, alkylated cellulose derivatives, and hemicellulose.

[0039] Preferably, the second polymer is an acetylated cellulose derivative. The acetylated cellulose derivative is one or more of cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate. In certain embodiments, the acetylated cellulose derivative is cellulose acetate.

[0040] In some embodiments, the cellulose acetate has a degree of acetylation in the range of 1 to 3. In some applications of film materials, the cellulose acetate has a degree of acetylation of at least 2. In some applications, an acetylation degree of approximately 2.5 may be desirable. In some alternative applications of film materials, the cellulose acetate has a degree of acetylation of less than 2.

[0041] Further, a packaging material comprising: A substrate; At least one layer formed from a film material as described above and assembled into a substantially continuous film on the support surface of the substrate; wherein the layer is formed to a thickness effective to provide a barrier to the transmission of oxygen and / or water vapor to the support surface of the substrate.

[0042] Preferably, the or each layer of film material has a thickness of at least 5 grams per meter2 (gsm) thick. The layer or layers of film material are 20 grams per meter 2 (gsm) or thicker.

[0043] Preferably, the layer of film material is formed to an average thickness of at least 2.5 μm, more preferably, the layer of film material is formed to an average thickness of at least 5 μm. In some embodiments, the support surface of the substrate is substantially planar. In some alternative embodiments, the support surface of the substrate is non-planar.

[0044] In some examples, the layer of film material may define an exterior surface of the packaging material. In some examples, the layer of film material may alternatively or additionally define an interior surface of the packaging material.

[0045] In some embodiments, the packaging material defines a recessed portion in which the consumable is to be packaged. The packaging material may be arranged such that a layer of film material is between the substrate and the recessed portion. Alternatively or additionally, the packaging material may be arranged such that the substrate is between the layer of film material and the recessed portion.

[0046] Alternatively or more specifically, the layer of film material has an oxygen transmission rate of the packaging material of 30 cubic centimeters per square meter per day (cm) at 23° C. and 50% relative humidity. 3 / (m 2 In certain embodiments, the layer of film material may be formed on the substrate at a thickness such that the oxygen transmission rate of the packaging material is less than or equal to 15 cubic centimeters per square meter per day (cm) at 23° C. and 50% relative humidity. 3 / (m 2 x days)) or less. In some particular embodiments, the layer of film material has an oxygen transmission rate of the packaging material of 13 cubic centimeters per square meter per day (cm) at 23° C. and 50% relative humidity. 3 / (m 2 The film is formed on the substrate to a thickness of not more than x days.

[0047] Preferably, the substrate is formed from or includes pulp fibers that have been gathered and processed into a predetermined shape and treated to form bonds between the pulp fibers within the substrate, thereby enabling the substrate to at least partially maintain its shape when unsupported.

[0048] In some embodiments, the substrate can be a multi-layer material having: a primary layer formed from or including pulp fibers that have been collected and processed into a predetermined shape and treated to form bonds between the pulp fibers; One or more secondary layers formed separately from the primary layer and the layer comprising the film material.

[0049] Preferably, at least some of the materials of the secondary layer are functionally distinct from the primary and secondary layers. Further provided is a method of forming a film material, the method comprising: forming a mixture of a first polymer dispersed and / or dissolved in a solvent, the first polymer being synthesized from one or more bio-based monomers and having a molecular weight of 60 kilodaltons or less; adding a second polymer to the mixture such that the second polymer is dispersed and / or dissolved, the second polymer being one of one or more bio-based derived carbohydrates and functionalized carbohydrates; and evaporating the solvent from the mixture of the solvent and the first and second polymers to form a film material; wherein the second polymer is added to the mixture such that the feed ratio of the second polymer to the first polymer in the mixture is at least 25:75 by weight.

[0050] Preferably, the second polymer is added to the mixture such that the feed ratio of the second polymer to the first polymer in the mixture is within the range of 80:20 to 10:90 by weight. More preferably, the second polymer is added to the mixture such that the feed ratio of the second polymer to the first polymer in the mixture is within the range of 75:25 to 25:75 by weight. Even more preferably, the second polymer is added to the mixture such that the feed ratio of the second polymer to the first polymer in the mixture is approximately 50:50 by weight.

[0051] In a particularly preferred embodiment of the method, the first polymer is synthesized from monomers of lactic acid and glycolic acid. Preferably, the first polymer is poly(lactic-co-glycolic acid) (PLGA). Poly(lactic-co-glycolic acid) may be formed from lactic acid and glycolic acid in a monomer ratio ranging from 40:60 to 85:15. More preferably, poly(lactic-co-glycolic acid) may be formed from lactic acid and glycolic acid in a monomer ratio ranging from 50:50 to 75:25. Alternatively or additionally, poly(lactic-co-glycolic acid) may be formed from lactic acid and glycolic acid with approximately equal proportions of lactic acid and glycolic acid monomers present during polymerization.

[0052] In particularly preferred embodiments of the method, the second polymer is an acetylated cellulose derivative, hi certain embodiments, the acetylated cellulose derivative is cellulose acetate.

[0053] Preferably, the first polymer has a molecular weight of 30 kilodaltons or less. More preferably, the first polymer has a molecular weight of 15 kilodaltons or less. Even more preferably, the first polymer has a molecular weight in the range of 4 kilodaltons to 8 kilodaltons. Even more preferably, the first polymer has a molecular weight in the range of 5.6 kilodaltons to 7.5 kilodaltons. In certain embodiments, the first polymer has a molecular weight of approximately 5.6 kilodaltons.

[0054] In certain instances, the first polymer has a polydispersity index of 3 or less. Further, the first polymer may have a polydispersity index of 2 or less. Still further, the first polymer may have a polydispersity index that is in the range of 1.35 to 1.75. In some instances, the first polymer has a polydispersity index that is in the range of 1.5 to 1.6.

[0055] The method may include selecting a solvent in which both the first and second polymers are soluble. Alternatively or additionally, the method may include selecting a solvent in which both the first and second polymers are dispersible. The solvent may be water and / or one or more volatile liquids. Preferably, the solvent is an organic solvent. More preferably, the solvent is a ketone. Even more preferably, the solvent is acetone.

[0056] The method may further include transferring the mixture of the solvent and the first and second polymers onto a target surface on which the film material is to be formed, at least partially prior to evaporating the solvent.

[0057] In some embodiments, the method may further include selecting an initial amount of solvent sufficient to completely dissolve and / or disperse each of the first and second polymers. More specifically, the method may include selecting an initial amount of solvent to achieve a predetermined viscosity of the mixture of the solvent and the first and second polymers before evaporating the solvent. Furthermore, the predetermined viscosity may be selected to facilitate application of the mixture of the solvent and the first and second polymers to a target surface on which the film material is to be formed. Preferably, the initial amount of solvent is selected such that the percentage of solvent in the mixture of the solvent and the first and second polymers is between 65% and 95%. More preferably, the initial amount of solvent is selected such that the percentage of solvent in the mixture of the solvent and the first and second polymers is between 80% and 90%. Even more preferably, the initial amount of solvent is selected such that the percentage of solvent in the mixture of the solvent and the first and second polymers is approximately 85%.

[0058] In some embodiments, evaporating the solvent includes heating the mixture to a temperature above the glass transition temperature of the first polymer. Alternatively or additionally, evaporating the solvent may include directing an air flow toward a surface of the mixture.

[0059] The method may further comprise tempering the film material after the solvent has evaporated. Preferably, tempering the film material comprises maintaining the treated material at an elevated temperature for a predetermined period of time. Preferably, the elevated temperature is above the glass transition temperature of the first polymer.

[0060] Preferably, the method comprises forming the film material to an average thickness in the range of 2.5 to 100 μm, more preferably, the method comprises forming the film material to an average thickness in the range of 5 to 50 μm.

[0061] In some embodiments, the target surface is a molding surface and the method includes applying a mixture of a solvent and the first and second polymers onto the molding surface and removing the formed film material from the molding surface.

[0062] In certain embodiments, the target surface is the surface of the packaging component that will bear the film material, such that the film material will adhere to the surface of the packaging component.

[0063] Alternatively or additionally, transferring the mixture of the first and second polymers onto the target surface includes applying the mixture to the target surface by extrusion coating, tumble coating, granulation, spray coating, casting, etc. Many suitable coating methods are known in the art and can be practiced by one of ordinary skill in the art without undue experimentation given the teachings herein.

[0064] The method may further include synthesizing the first polymer from the first monomeric material and the second monomeric material, the synthesizing comprising: creating a feed mixture by adding a second monomeric material to an aqueous solution having the first monomeric material dispersed therein in a predetermined molar ratio of the first monomeric material to the second monomeric material; dehydrating the feed mixture under predetermined dehydration conditions; oligomerizing the dehydrated feed mixture in a polymerization catalyst; performing post-synthetic finishing on the oligomerization feed mixture and subsequently isolating a first polymer; Includes.

[0065] The polymerization catalyst may be a Bronsted acid catalyst, a Lewis acid catalyst, or an organic catalyst. Preferably, the polymerization catalyst is a sulfonic acid. In embodiments where the polymerization catalyst is a Bronsted acid catalyst, the polymerization catalyst can be one of methanesulfonic acid, p-toluenesulfonic acid, or trifluoromethanesulfonic acid.

[0066] In embodiments where the polymerization catalyst is a Lewis acid catalyst, the polymerization catalyst may be one or more metal alkoxides. Preferably, the polymerization catalyst is one of aluminum isopropoxide, stannous chloride, urea / potassium alkoxide, stannous octoate, or tin alkoxide.

[0067] In embodiments where the polymerization catalyst is an organic catalyst, the polymerization catalyst is one or more nucleophilic bases. Preferably, the polymerization catalyst is one of 4-dimethylaminopyridine, a heterocyclic carbene, a thiourea-amine catalyst, or tris[2-(dimethylamino)ethyl]amine (Me6TREN).

[0068] In embodiments where the first monomeric material is lactic acid and the second monomeric material is glycolic acid, the polymerization catalyst is a compound of tin (Sn). In a preferred embodiment, the polymerization catalyst is tin(II) 2-ethylhexanoate (Sn(Oct) 2 )).

[0069] In order that the invention may be more readily understood, embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0070] [Figure 1] FIG. 1 is a graph showing WVTR test results for samples of grease resistant sheeting coated with a 20 gsm film material according to an embodiment, the tests being conducted at 23° C. and 50% relative humidity (RH). [Diagram 2] FIG. 2 is a graph depicting relative OTR test results for samples of thermoformed pulp fiber sheets each having a coating of a film material according to an embodiment at a coating weight of 20 gsm. [Diagram 3] FIG. 3 is a bar graph showing Cobb test results for samples of thermoformed pulp fiber sheets coated with film materials according to embodiments. [Figure 4] FIG. 4 is a bar graph showing migration test results for samples of thermoformed pulp fiber sheets, some of which were coated with film materials according to embodiments. [Diagram 5] FIG. 5 is a scanning electron microscope (SEM) image of a sample surface of a film material according to an embodiment, generated with micrometer-scale resolution in the image plane. [Figure 6] FIG. 6 is an atomic force microscope (AFM) image of a sample surface of a film material according to an embodiment, the image being generated with micrometer-scale resolution in the image plane. [Figure 7] FIG. 7 is an atomic force microscope (AFM) image of a portion of the surface of the film material shown in FIG. 6, magnified in the image plane to nanometer-scale resolution. [Figure 8] FIG. 8 is a graph showing the spectrum of a sample of synthesized PLGA, the graph being obtained by proton nuclear magnetic resonance (NMR) spectroscopy. [Figure 9]FIG. 9 is a graph showing the molecular weight distribution of the synthesized PLGA samples, which was obtained by gel permeation chromatography (GPC) analysis. [Figure 10] FIG. 10 is a graph showing the crystallographic structure of the synthesized PLGA samples, which was obtained by x-ray diffraction (XRD) analysis. [Figure 11] FIG. 11 is a graph showing the results of differential scanning calorimetry performed on the synthesized PLGA samples. [Figure 12] FIG. 12 is a schematic cross-sectional view of a MOCON OX-TRAN Oxygen Permeation Analyzer Model 2 / 22 TruSeal test cell, which was the test cell used to obtain OTR results such as those shown in FIG. [Figure 13] FIG. 13 is a schematic diagram of the Cobb test apparatus used to obtain Cobb results such as those shown in FIG. [Figure 14] FIG. 14 is an atomic force microscope (AFM) image of a sample surface of a film material according to an embodiment, the image being generated with micrometer-scale resolution in the image plane. [Figure 15] FIG. 15 is an atomic force microscope (AFM) image of a sample surface of a film material according to an embodiment, the image being generated with micrometer-scale resolution in the image plane. [Figure 16] FIG. 16 is an atomic force microscope (AFM) image of a sample surface of a film material according to an embodiment, the image being generated with micrometer-scale resolution in the image plane. [Figure 17] FIG. 17 is an atomic force microscope (AFM) image of a sample surface of a film material according to an embodiment, the image being generated with micrometer-scale resolution in the image plane. [Figure 18] FIG. 18 is an atomic force microscope (AFM) phase image of a sample surface of the film material of FIG. 16, the image generated with micrometer-scale resolution in the image plane. [Figure 19] FIG. 19 is a photograph of a sample of a film material according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0071] Embodiments will now be described with reference to the following examples. It should be understood that these embodiments and examples are provided as illustrations of the invention and that they are in no way intended to limit the scope of the invention.

[0072] Example 1: Synthesis of film materials Chemicals: Poly(lactic-co-glycolic acid) (PLGA): - As-synthesized; Cellulose Acetate (CA): - Obtained from Sigma Aldrich (product number: 180955), - powder form, - average molecular weight (Mn): 30 kilodaltons, - acetylation: 39.8% (by weight), - Used as received; acetone: - Obtained from Merck (product number: 100014), - Reagent grade, - Used as received The cellulose acetate obtained from Sigma Aldrich was listed as having 39.8% acetylation by weight, which in turn can be expressed as a degree of acetylation of approximately 2.45 (which can be rounded to 2.5).

[0073] Base material: High Density Poly(ethylene) (HDPE) Sheets: - Obtained from Plastic Centre (Melbourne, Australia) - Thickness 1.5mm (nominal value), - Used as received Grease-resistant sheet: - compostable brown paper (Glad to be Green®), - 40gsm, - Retail grade, - Used as received Thermoformed pulp fiber sheets: - Molded from raw bagasse fibre obtained from Sheeon, - Substantial flat form with sheet weight of 400gsm, - thermoformed by the Applicant, including: Beating raw bagasse fiber in accordance with the Technical Association of the Pulp and Paper Industry (TAPPI) T248 SP-15 Standard, “Laboratory Beating of Pulp (PFI Mill Method)”, April 2015, with a mill up to 3000 revolutions, and b. Using an apparatus including a tool substantially as described and shown in International Patent Application No. PCT / AU2020 / 051248, filed in the name of Varden Process Pty Ltd., entitled "A Tool for use in a Thermoforming Process."

[0074] method: The desired molar fractions of PLGA and CA were dissolved in acetone, followed by heating to 20° C.-30° C., ideally 25° C., and maintaining under constant stirring for up to 2 hours until dissolved to form a dissolved PLGA:CA blend. In various experiments, PLGA and CA were tested dissolved in acetone at concentrations of 5 wt%, 10 wt%, 15 wt%, and 25 wt%.

[0075] The molten PLGA:CA blend was delivered to the selected substrate material in a mass that achieved the desired coat weight. In various experiments, 10 g / m 2Coat weights of 1000 gsm (also known as "grams per square meter" or "gsm"), 20 gsm, and 30 gsm were tested. The acetone solvent was evaporated by placing the coated sheet in an environment of elevated temperature and cross-flow air current for a predetermined period of time. Specifically, the acetone solvent was evaporated in a drying oven as follows: - temperature within the range of 20°C to 56°C, ideally 50°C; - Average air flow in the range of 1.2m / s to 3m / s, ideally 1.5m / s; and - Duration should be between 180 seconds and 340 seconds, with 210 seconds being the ideal duration.

[0076] analysis: Water vapor barrier: As will be appreciated, in the context of packaging materials, the effectiveness of a material as a barrier to water vapor can be an important factor in the performance of the packaging material.

[0077] Samples of PLGA:CA blend films (according to Table 1 below) formed on grease-resistant sheets with a coating weight of 20 gsm were prepared by the method described above. These samples were subjected to Water Vapor Transmission Rate (WVTR) testing using air at 23°C and 50% relative humidity (RH) as the migration test agent. In addition, samples of PLGA only films formed on grease-resistant sheets with a coating weight of 20 gsm were also prepared by the method described above.

[0078] [Table 1]

[0079] The above results are shown graphically in Figure 1. The results show that the water vapor barrier properties of the PLGA:CA blend film materials decrease with increasing percentage of cellulose acetate (CA).

[0080] Oxygen gas barrier properties: As will be appreciated, in the context of packaging materials, the effectiveness of a material as a barrier to oxygen gas can be an important factor in the performance of the packaging material.

[0081] Samples of PLGA:CA blend film material (according to Table 2 below) were prepared by the method described above and then coated on a substrate comprising a thermoformed pulp fiber sheet by the applicant at a coating weight of 20 gsm. These samples were subjected to oxygen transmission rate (OTR) testing using a MOCON OX-TRAN Oxygen Permeation Analyzer Model 2 / 22. In addition, indexing samples of PLGA-only film material were prepared substantially by the method described above, but excluding the second polymer (cellulose acetate), and then coated on a substrate comprising a thermoformed pulp fiber sheet, also at a coating weight of 20 gsm.

[0082] For comparison purposes, the test results of Samples 6, 7, and 8 (PLGA:CA blend film materials) are indexed to Sample 5. Thus, the indexed oxygen transmission rates (OTR) of Samples 6, 7, and 8 are a percentage of the results of the index sample (Sample 5), and therefore the indexed OTR for Sample 5 is 1.

[0083] [Table 2]

[0084] The above results are shown graphically in Figure 2. The results show that the oxygen gas barrier properties of the PLGA:CA blend film materials increase with increasing percentage of cellulose acetate (CA).

[0085] The MOCON OX-TRAN Oxygen Permeation Analyzer Model 2 / 22 test cell is shown diagrammatically in FIG. 12 and described below. Liquid water barrier: As will be appreciated, in the context of packaging materials, the effectiveness of a barrier to liquid water can be an important factor in the performance of the packaging material.

[0086] The Cobb test is a measurement of water absorption from a surface. Specifically, the test determines the amount of water absorbed from the surface of a material in a set period of time. The Cobb test involves exposing a standard area to water for a set period of time and measuring the amount of water (g / m2) absorbed by the material. 2 or "gsm"). Samples of material having a substrate coated with a film of the PLGA:CA blend prepared above are subjected to the Cobb test to obtain a measurement of the ability of the film to act as a barrier to liquid water.

[0087] Samples of films of PLGA:CA blends formed on thermoformed pulp fiber sheets at nominal coating weights (according to Table 3 below) were prepared by the method described above. In addition, samples of PLGA-only films formed on thermoformed pulp fiber sheets were also prepared by the method described above.

[0088] [Table 3]

[0089] The above results are shown in the bar graphs of Figure 3. Overall, these results indicate that the liquid water barrier properties of the PLGA:CA blend film materials are: - cellulose acetate is present in the blend but has an optimum value when it is less than 75%; and - may increase (possibly exponentially) with increasing coat weight of the film material; Shows.

[0090] For Samples 1-15, the results of the tests described above indicate that film materials formed from PLGA and CA components in an approximately 50:50 weight ratio provide beneficial barrier performance with respect to all of water vapor, oxygen (gas), and liquid water.

[0091] PLGA:CA film transition to packaging As will be appreciated, in the context of packaging materials intended for use in packaging consumable items, migration of the packaging material into the consumable item can be detrimental to the item.

[0092] The Migration Test is a measurement of the residue of material that has migrated (i.e., leached) from a material into an item stored in contact with the material. Samples of the material having a substrate coated with a film of the PLGA:CA blend are subjected to the Migration Test to obtain a measurement of the amount of film material that migrates into the consumable item.

[0093] Samples of films of PLGA:CA blends formed on thermoformed pulp fiber sheets at nominal coating weights (according to Table 4 below) were prepared by the methods described above. In addition, samples of uncoated thermoformed pulp fiber sheets and samples of CA-only films formed on thermoformed pulp fiber sheets were also prepared by the methods described above.

[0094] The migration test was carried out by the applicant according to the European Standard EN 1186-9 for materials in contact with foodstuffs. The test involves contacting an aqueous food simulant with the sample material and subjecting the simulant and sample to a temperature of 100°C for 30 minutes. According to the requirements of the European Food Contact Regulation, for packaging materials, <10mg / dm 2 A migration residue value of less than is required.

[0095] [Table 4]

[0096] The results are shown in the bar graphs of Figure 4. The results show that the film material with a 50:50 PLGA:CA blend has a residue content that meets the European food contact regulations.

[0097] Example 2: Synthesis of low molecular weight PLGA from bio-based monomers Chemicals: Lactic acid: - Obtained from Sigma Aldrich (product number: W261114), - Liquid, contains 85% by volume, with the remaining 15% being water, larger oligomers of lactic acid, and other FEMA GRAS ingredients; - Used as received; Glycolic Acid: - Obtained from Sigma Aldrich (product number: 124737), - Powder form, content 99%, - Used as received; Tin(II) 2-ethylhexanoate: - Obtained from Sigma Aldrich (product number: S3252), - Liquid, content 92.5~100%, - Used as received; Chloroform: - Obtained from Sigma Aldrich (product number: C2432), - liquid, - Used as received; methanol: - Obtained from Sigma Aldrich (product number: 179957), - liquid, - Used as received

[0098] method: Appropriate amounts of lactic and glycolic acid feeds were mixed to achieve the desired monomer feed ratio, followed by heating to 160°C under gentle partial vacuum (100 mbar) and maintaining with constant stirring for 2 hours. The polymerization catalyst (tin(II) 2-ethylhexanoate) was then charged to the reaction, the temperature was raised to 180°C, and partial vacuum was increased (to <5 mbar) and maintained with constant stirring for 4-16 hours. The synthesis reaction mixture was cooled to room temperature and dissolved in chloroform. Methanol was then added to the solution, followed by stirring the reaction solution and allowing it to separate. The resulting supernatant was poured off. The remaining solute was blown off by a compressed air stream to form a precipitate. Finally, the precipitate was dried in a vacuum oven at 35°C for 24 hours, thus leaving the synthesized poly(lactic-co-glycolic acid) (PLGA) in powder form. The PLGA polymer was made with a 50:50 lactic acid to glycolic acid monomer feed molar ratio.

[0099] analysis: A sample of PLGA synthesized as described above was analyzed using a Bruker Nuclear Magnetic Resonance (NMR) spectrometer. Figure 8 is a graph showing the proton (1H) nuclear magnetic resonance spectrum of the sample. For this analysis, the sample was dissolved in chloroform (CHCl 3 ) was dissolved.

[0100] In FIG. 8, the clusters in the spectrum are as follows:

[0101] [Table 5]

[0102] In the table: Chl: equivalent to chloroform solvent; L 1 : corresponds to the methine group of the lactic acid component in the sample, G: corresponds to the methylene group of the glycolic acid component in the sample, L 2 : corresponds to the methyl group of the lactic acid component in the sample, "H's": the number of hydrogen atoms in the corresponding functional group.

[0103] The methine group (L 1 ) and the signal intensity values ​​of the methylene group (G) of glycolic acid, the percentage of glycolic acid ester present in the sample can be calculated as follows. L 1 Intensity (I L ) = 0.7, and G intensity (I G ):0.96

[0104]

number

[0105] Thus, the results obtained from proton NMR spectroscopy (and shown in FIG. 8) suggest that the sample has a ratio of lactic acid to glycolic acid units in the polymer of approximately 60:40.

[0106] A sample of PLGA synthesized as described above was analyzed using gel permeation chromatography. Figure 9 is a graph showing the molecular weight distribution of the sample. The results from the gel permeation chromatography analysis show that the sample has: Number average molecular weight (Mn): 4.857×10 3 g / mol Weight average molecular weight (Mw): 8.116×10 3 g / mol Polydispersity Index (PDI): 1.67 A sample of PLGA synthesized as described above was analyzed using an x-ray diffractometer. Figure 10 is a graph showing the intensity (counts) versus phase angle (2θ) from an x-ray diffraction analysis. The results from this analysis suggest that the sample material has 40% crystallinity, with the remainder (60%) being amorphous.

[0107] A sample of PLGA synthesized as described above was analyzed using a differential scanning calorimeter. Figure 11 is a graph showing heat flow (mW) versus temperature (°C) from differential scanning calorimetry. Results from this analysis suggest that the sample has a glass transition temperature (Tg) of approximately 32.56°C.

[0108] It should be understood that tin (II) 2-ethylhexanoate, also known to those skilled in the art as "stannous octoate," "stannous octoate," and / or "stannous octoate," is a polymerization catalyst synthesized with tin.

[0109] It is understood that the method of Example 2 described above includes the synthesis of PLGA by polycondensation. The synthesis of PLGA with the same or substantially similar properties can be achieved by other polymerization methods. By way of example only, chain polymerization methods such as ring-opening can be used.

[0110] FIG. 5 is a scanning electron microscope (SEM) image of the surface of a film material formed from a PLGA:CA blend made according to Example 1, the film material having substantially equal amounts of the two polymers present in the blend. The image in FIG. 5 was generated at a micrometer scale resolution in the image plane, and the scale is shown in the image. In the SEM image, the PLGA component of the blend can be identified by the dark gray areas of the surface surrounded by a light gray annular morphology. The CA component of the blend can be identified by the medium gray areas. Thus, the SEM image suggests that in the film material, domains of PLGA are dispersed within an interconnected matrix of cellulose acetate.

[0111] Figures 6 and 7 are atomic force microscope (AFM) images of the surface of a film material formed from a PLGA:CA blend made according to Example 1, the film material having substantially equal amounts of the two polymers present in the blend. The image in Figure 6 was generated with a micrometer-scale resolution in the image plane, and a scale is shown in the image. The image in Figure 7 is a portion of the surface of the film material shown in Figure 6, enlarged to a nanometer-scale resolution in the image plane, and a scale is shown in the image. In each image, the surface height is represented by the shading of the image, with a corresponding range of high to low areas represented by the light to dark color of the image according to the shading bar to the right of the actual image.

[0112] The AFM image in Figure 6 shows that the surface of the film material is approximately 6.2 nanometers (i.e., 6.2 × 10 -9 The AFM image of FIG. 7 shows that the surface of the film material has a maximum surface height difference of approximately 4.03 nanometers (i.e., 4.03×10 -9 m) indicates that the image area has a surface unevenness difference within the image area.

[0113] Further evaluation of the images in Figures 6 and 7 suggests that within the PLGA:CA blend, the two polymers remain highly intermixed throughout the solvent drying process.

[0114] Applicants understand that the relatively low molecular weight of the synthesized PLGA maintains the highly mixed structure of the blend. This allows the PLGA:CA blends according to the embodiments to achieve surprisingly high barrier properties for both water vapor and oxygen within the same material. In addition, these PLGA:CA blends can simultaneously retain the strength and hydrophobicity of cellulose acetate (CA) and the flexibility and low oxygen permeability of poly(lactic-co-glycolic acid) (PLGA). The benefits of a strong yet flexible polymeric material with surprisingly high resistance to both water vapor and oxygen permeation are provided within the same material, a benefit not suggested by known bio-based and biodegradable polymer blends. Such high barrier properties are not consistent with the conventional understanding of PLGA or CA, especially since the properties of film materials formed from either PLGA or CA individually suggest that acceptable or even desirable WVTR and OTR properties could not be simultaneously achieved from blends of these materials. The same is true for film materials formed from individual polymers of other bio-based monomers.

[0115] Additionally, additional properties of PLGA:CA blends according to embodiments provide migration performance and barrier properties to liquid water, which are also surprising. Additional benefits of film materials formed from PLGA:CA blends according to embodiments include that the material is bio-derived, that the film material is biodegradable and / or compostable, and that the material has desirable flexibility, brittleness, and transparency.

[0116] 12 is a schematic longitudinal cross-sectional view of an oxygen permeation test cell 10. Cell 10 has an upper shell portion 12 and a lower shell portion 14 closed relative to one another to define an interior cavity 16. A test sample S may be captured between the upper and lower shell portions 12, 14. The contacting surfaces of each of the upper and lower shell portions 12, 14 are configured to create a seal against the test sample S.

[0117] As shown in FIG. 3, trapping the test sample S between the upper and lower shell portions 12, 14 divides the cavity 16 into an upper cavity region and a lower cavity region.

[0118] The lower shell portion 14 is made of oxygen (O 2 1.) gas inlet 18 through which oxygen gas is supplied to cavity 16. Vent 20 is configured to evacuate cavity 16 to a nominal cavity pressure, typically atmospheric pressure. In this manner, the lower cavity region can be filled with oxygen gas and maintained at the nominal cavity pressure.

[0119] The upper shell portion 12 has a carrier gas inlet 22 through which a carrier gas is supplied to the cavity 16. The carrier gas is typically nitrogen (N 2 ), where during testing, nitrogen gas is provided at a relatively constant flow rate through gas inlet 22. Upper shell portion 12 also has a sample gas outlet 24. During testing, carrier gas displaces gas from within the upper cavity region, and the displaced gas exits cavity 16 through sample gas outlet 24. By analyzing the amount of oxygen present in the displaced gas exiting through sample gas outlet 24, the oxygen permeability of test sample S can be determined.

[0120] Oxygen (O 2 ) The gas inlet 18 and the carrier gas inlet 22 each include a humidity sensor 26 to facilitate accurate and reliable testing of the samples. Figure 13 is a schematic diagram of a Cobb test fixture 100. The fixture 100 includes a base plate 102 and a cylindrical shell 104. When the fixture 100 is in use, a test sample is inserted between the base plate 102 and the base of the cylindrical shell 104. In Figure 13, the test sample position is indicated by the arrow TS.

[0121] A pair of posts 108 are fixed to the base plate 102. A clamp bar 106 is placed across the top of the cylindrical shell 104, with the posts 108 passing through holes in the clamp 106. A threaded fastener 110 is then tightened to compress the test sample between the base plate 102 and the cylindrical shell 104.

[0122] The cylindrical shell 104 has a defined inner diameter so that the interior cavity 112 can be filled to a predetermined volume, for example by filling the interior of the shell 104 to a predetermined depth. In the actual test, the test sample is exposed to water for a predetermined time, usually 60 seconds or 180 seconds (known as the Cobb 60 or Cobb 180 test, respectively).

[0123] Example 3: Synthesis of film materials Chemicals: Poly(lactic-co-glycolic acid) (PLGA): - Obtained from, commissioned by, and synthesized according to the applicant's specifications; - powder form, - Used as received; Cellulose Acetate Butyrate (CAB): - Available from Eastman (product number: CAB-381-0.5), - powder form, - Used as received (referred to herein as "CAB-381-0.5 (Eastman)"); Cellulose Acetate Propionate (CAP): - Obtained from Sigma Aldrich (product number: 340642), - powder form, - Used as received (referred to herein as "CAP (Sigma)"); Cellulose Acetate Propionate (CAP): - Obtained from Eastman (product number: CAP-482-0.5, Food Contact), - powder form, - Used as received (referred to herein as "CAP-482-0.5 (Eastman)"); acetone: - Obtained from Merck (product number: 100014), - Reagent grade, - Used as received Analysis of the results obtained from proton NMR spectroscopy of PLGA indicated a ratio of lactic to glycolic acid units in the polymer of approximately 60:40.

[0124] Base material: Derwent Tracing Paper: - 92gsm, - Retail grade, - Used as received

[0125] method: According to Example 1, all coating materials were prepared as acetone solutions with a molar fraction of 50 wt% PLGA, with the remainder being the acetylated cellulose derivative component. The polymer blend in solution was delivered to a substrate material to achieve a coat weight of 30 gsm.

[0126] analysis: Samples of films of the coating material blends formed on substrate materials. Each sample was subjected to OTR and WVTR testing as detailed in the analysis of Example 1. The results are shown in Table 5 below.

[0127] [Table 6]

[0128] Figures 14-17 are atomic force microscope (AFM) images of the surface of film materials formed from blends of PLGA and a second polymer (cellulose acetate or acetylated cellulose derivative) in Example 3, as detailed below in Table 6. All samples were prepared by delivering a 50 wt % molar fraction of PLGA to the substrate material, with the remainder being the second polymer.

[0129] The images were generated with a micrometer-scale resolution in the image plane, and the scale is indicated in the corresponding image. The maximum surface height difference in the imaged area for each sample is shown in Table 6. Sample 24 was made according to Example 1, but using the PLGA component of Example 3.

[0130] [Table 7]

[0131] The image in FIG. 15 is a close-up portion of the surface of the film material shown in FIG. Figure 18 is an AFM phase image of Sample 25, and thus corresponds to the surface image of Figure 16. In this image, the phase shift is represented by the shading of the image, with the dark to light color of the image correspondingly representing a phase shift range of 0° to 13.8° (maximum) according to the shading bar on the right side of the actual image. It is understood that with respect to Sample 25, the PLGA component is softer and / or more adhesive to the AFM probe tip compared to the CAP (Sigma) component in the film material.

[0132] In the surface images of Figures 14-17, the PLGA is identifiable by the downwardly recessed dark regions that are surrounded by an interconnected matrix of a second polymer. Analysis of Figures 5-7 and 14-18 indicates that the polymer blends of each film material form a continuous film. Within the surface layer of each film material, the corresponding second polymer (CA, CAP, CAB) is arranged as a substantially continuous matrix surrounding the domains of PLGA. Furthermore, within the surface layer of each film material, domains of PLGA of various sizes and / or spacing are present.

[0133] Example 4: Synthesis of film materials: Chemicals: Poly(lactic-co-glycolic acid) (PLGA): - Obtained from, commissioned by, and synthesized according to the applicant's specifications; - powder form, - Used as received; Cellulose Acetate (CA): - Available from Eastman (product number: CA-398-3, Food Contact); - powder form, - acetylation: 39.8% (by weight), - Used as received; acetone: - Obtained from Merck (product number: 100014), - Reagent grade, - Used as received

[0134] method: PLGA and CA were dissolved in acetone in a molar ratio of 50:50 by weight, then heated to 20°C-30°C, ideally 25°C, and maintained under constant stirring for up to 2 hours until dissolved to form a dissolved PLGA:CA blend.

[0135] The molten PLGA:CA blend was delivered to a silicone curing vessel in a mass that would achieve the desired film thickness. The acetone solvent was evaporated at standard laboratory temperature as follows: - on a laboratory bench for a period ranging from 20 to 60 minutes, ideally 30 minutes, and followed by a second period in the range of 20 to 60 minutes, ideally 30 minutes, in an environment of increased cross-flow airflow. Once the acetone solvent had evaporated, the film material was peeled from the curing vessel. FIG. 19 is a photograph of the film material made according to the method described above.

[0136] analysis: Water vapor barrier: Film samples of PLGA:CA blends formed at various thicknesses (according to Table 7 below) were prepared by the method described above and were subjected to water vapor transmission rate (WVTR) testing using air at 23°C and 50% relative humidity (RH) as the migration test agent.

[0137] [Table 8]

[0138] The above results show that the water vapor barrier properties of the film material according to Example 4 increase with film thickness. The term "bio-based monomers" refers to monomers that are derived from renewable resources / renewable feedstocks. These include bio-derived, naturally occurring, and / or bio-derived monomers. Similarly, the term "bio-based" refers to materials that are derived from renewable resources / renewable feedstocks. These include bio-derived, naturally occurring, and / or bio-derived materials.

[0139] The term "biodegradable" is recognized in the art and includes polymers, compositions, and formulations, such as those described herein, that are intended to degrade during use by biological means, such as bacteria and fungi, in addition to degradation by other chemical processes, such as hydrolysis, oxidation, and enzymatic processes, and / or by anaerobic means. Such uses include degradation to effect and control the release of active ingredients. Generally, degradation attributed to biodegradability involves the breakdown of a biodegradable polymer into its component subunits, monomers, and oligomers, ultimately resulting in non-toxic by-products.

[0140] In this specification and the following claims, the expression "degree of acetylation" is understood to mean the average number of acetyl groups per carbohydrate unit in the material. The degree of acetylation can also be expressed as "degree of substitution" to indicate the average number of hydroxyl groups replaced with acetyl groups per carbohydrate unit in the material. For this purpose, in the case of cellulose acetate, each carbohydrate unit can have 1, 2 or 3 acetyl groups after acetylation, and the degree of acetylation is understood to be a value that represents the degree of substitution (of acetyl groups for hydroxyl groups).

[0141] In this specification and the claims that follow, any reference to a monomer, polymer, or copolymer should be understood to include all stereoisomers (i.e., chirality) that may exist in the corresponding monomer, polymer, or copolymer, unless the context clearly indicates otherwise. As a non-limiting example, a reference to a monomer having a stereoisomer should be understood to include a compound that is substantially only its L-isomer, substantially only its D-isomer, and a combination of both L- and D-isomers (unless clearly indicated / stated otherwise). Similarly, a polymer formed from one or more monomers having a stereoisomer should be understood to include a polymer that, for each monomer, is substantially only its L-isomer, substantially only its D-isomer, and a combination of both L- and D-isomers (unless clearly indicated / stated otherwise).

[0142] As used herein, the terms "consumables" and "goods" refer to products that deteriorate (i.e., degrade, spoil, rot, and / or decompose) over time, where the least amount of deterioration is most desirable for its intended use. Thus, "consumables" and "goods" include food and beverage products for human or animal consumption; pharmaceuticals, nutraceuticals, and dietary supplements for human or animal use; and cosmetics. For the avoidance of doubt, "consumables" and "goods" also include various garden and household items that are intended for human / animal use but not for ingestion. It is understood that this is not an exhaustive list of products that are "consumables" and / or "goods".

[0143] Throughout this specification and the claims which follow, unless expressly stated otherwise, references to "molecular weight" should be understood to mean "weight average molecular weight." Throughout this specification and the claims that follow, unless the context requires otherwise, the word "comprise" and variations such as "comprises" and "comprising" are understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integers or steps or group of integers or steps.

[0144] Any reference in this specification to any prior publication (or information derived therefrom) or to any known matter is not, and should not be construed as, an acknowledgment or admission, or any form of suggestion, that that prior publication (or information derived therefrom) or known matter forms part of the common general knowledge within the scope of the endeavor to which this specification pertains.

Claims

**Claim 1** A packaging material comprising a substrate and at least one layer formed from a film material, wherein the film material comprises a blend of a first polymer synthesized from one or more bio-based monomers and having a molecular weight of 60 kilodaltons or less, and a second polymer which is one of a carbohydrate and a functionalized carbohydrate derived from one or more bio-based materials, the first polymer is an aliphatic polyester selected from poly(lactic acid), poly(glycolic acid), a copolymer of lactic acid and glycolic acid, a copolymer of lactic acid, glycolic acid and poly(ethylene glycol), poly(e-caprolactone), and poly(3-hydroxybutyrate), the ratio of the first polymer to the second polymer in the film material is at least 25:75 by weight, the at least one layer is assembled into a substantially continuous film on the holding surface of the substrate, the at least one layer is formed to a thickness effective to provide a barrier against the permeation of oxygen and / or water vapor to the holding surface of the substrate, A packaging material. **Claim 2** The packaging material according to claim 1, wherein the first polymer has a molecular weight of 30 kilodaltons or less. **Claim 3** The packaging material according to claim 1, wherein the first polymer has a molecular weight of 15 kilodaltons or less. **Claim 4** The packaging material according to claim 1, wherein the first polymer has a molecular weight in the range of 4.5 kilodaltons to 7.5 kilodaltons. **Claim 5** The packaging material according to claim 1, wherein the first polymer has a polydispersity index of 3 or less. **Claim 6** The packaging material according to claim 1, wherein the ratio of the first polymer to the second polymer in the film material is approximately 50:50 by weight. **Claim 7** The packaging material according to claim 1, wherein the first polymer is synthesized from monomers of lactic acid and glycolic acid. **Claim 8** The packaging material according to claim 1, wherein the first polymer is poly(lactic-co-glycolic acid) (PLGA). **Claim 9** The packaging material according to claim 8, wherein the poly(lactic-co-glycolic acid) is formed such that the ratio of lactic acid units to glycolic acid units is approximately 60:

40. **Claim 10** The packaging material according to claim 1, wherein the second polymer is an acetylated cellulose derivative. **Claim 11** ​ The packaging material according to claim 10, wherein the acetylated cellulose derivative is one or more of cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate.

12. The packaging material according to claim 10, wherein the acetylated cellulose derivative is cellulose acetate.

13. The packaging material according to claim 12, wherein the cellulose acetate has a degree of acetylation in the range of 1 to 3.

14. The layer or layers of the film material are formed to have a thickness of at least 5 grams per square meter ２ (gsm), the packaging material according to claim 1.

15. The packaging material according to claim 1, wherein the layer or each layer of the film material is formed to have an average thickness of at least 2.5 μm.

16. The packaging material according to claim 1, wherein the layer of the film material defines the outer surface of the packaging material.

17. The packaging material according to claim 1, wherein the layer of the film material defines the inner surface of the packaging material.

18. The packaging material according to claim 1, wherein the base material is formed from pulp fibers processed to be gathered into a predetermined shape and is treated to form a bond between the pulp fibers within the base material, whereby the base material can at least partially maintain its shape even in an unsupported state.

19. The packaging material according to claim 1, wherein the packaging material is formed to define a concave portion in which a consumable is to be packaged, and the packaging material is arranged such that the layer of the film material is present between the base material and the concave portion.

20. The layer of the film material is formed on the substrate with a thickness such that the oxygen transmission rate of the packaging material at 23°C and a relative humidity of 50% is 30 cubic centimeters per square meter per day (cm ３ / (m ２ ×day)) or less. The packaging material according to claim 1.

Images