Metallized paper multilayer packaging material

Abstract

The present invention relates to an oxygen barrier substrate comprising or consisting of a graft copolymer comprising a vinyl alcohol polymer backbone and polypeptide branches. The present invention also relates to packaging materials, particularly metallized paper-based multilayer packaging materials, comprising at least one oxygen barrier layer comprising or consisting of a graft copolymer comprising a vinyl alcohol polymer backbone and polypeptide branches.

Description

[Technical Field]

[0001] The present invention relates to a paper-based multilayer packaging material comprising a paper layer and an ultra-thin metal or metalloid layer for water vapor barrier sandwiched between ultra-thin coating layers that provide oxygen barrier and hermeticity to the structure. More precisely, the present invention relates to a paper-based multilayer packaging material in which at least one organic barrier layer comprises a graft copolymer comprising a vinyl alcohol polymer backbone and polypeptide branches. [Background technology]

[0002] Plastic packaging is frequently used in economic activities and people's daily lives. Plastic packaging has several advantages, such as flexibility and light weight. Lightweighting contributes to fuel savings and CO2 reduction, for example during transportation. The barrier properties of plastic packaging have a positive effect on extending shelf life and therefore help reduce food waste. Barrier properties also help ensure food safety.

[0003] However, due to increasing environmental awareness and to ensure a reduction in plastic waste, multi-layer packaging materials have been developed that comprise one paper or cardboard layer and one or more plastic or metal film layers to provide robustness and barrier properties, particularly oxygen and moisture barrier properties.

[0004] Recently, there has been an increased environmental awareness, especially with regard to waste materials, such as used packaging, that are not recycled or properly treated. This problem is considered very serious by the industry, which is devoting a great deal of effort to developing new packaging materials that are quickly and easily recyclable.

[0005] Currently, when producing multi-layer packaging structures, if layers of plastic are applied by known techniques, in particular by extrusion (extrusion lamination) or also by adhesive lamination processes, the thickness of the plastic film obtained on the paper is necessarily large.

[0006] Even when the extruded or laminated polymers in such multilayer structures are relatively thin, the cohesive strength of the polymer film is very high, as is the level of adhesion of the polymer to the paper or cardboard (i.e., cellulosic) substrate, which prevents the polymer from being removed from the substrate during recycling and prevents recycling and repulping of the cellulose fiber portion in the paper-stream recycling process.

[0007] Thus, multi-layer structures comprising a combination of paper and extruded or adhesively laminated (by conventional techniques such as extrusion lamination or extrusion coating) plastic (polymer) films have limited recyclability in standard paper recycling processes because the plastic layers are too thick to be dispersed during the subsequent recycling process and have too high a cohesive strength and adhesion level to adjacent layers of the structure to separate them from other layers of material, particularly from the paper fibers. The extruded plastic film remains intact in the paper pulp bath, thus making it difficult to recycle the paper pulp through a repulping process.

[0008] Furthermore, the above-mentioned known recycling processes for laminated materials are expensive, energy consuming, and characterized by a relatively low yield of recycled paper fibers (less than 80% of the total amount of packaging material in the entire structure), and therefore are not sufficiently environmentally friendly in terms of disposal and recycling. There is also room for improving the recyclability of the remaining parts of the packaging material (i.e., the plastic polymer part and the metal part, e.g., the aluminum part) in the paper recycling process.

[0009] Furthermore, in packaging for food products, good barrier properties are essential to maintain the safety and quality of the packaged food, typically including gas barrier (e.g., to oxygen and water vapor (moisture)) and, if possible, liquid-tightness.

[0010] One way to provide a good moisture barrier to paper-based packaging materials is the introduction of a metal or metalloid layer into a so-called "metallized" layer. As used herein, the term "metallization" (e.g., in the expression "metallized barrier paper layer") is meant to encompass the deposition of metal or metalloid atoms on the surface of paper or paperboard. One can even consider embodiments that include the deposition of alloys of metals and metalloids. Metalloids have some of their properties close to metals. Aluminum oxide and silicon oxide are examples of metalloids.

[0011] Problems associated with the introduction of metal layers into paper-based packaging materials include the sensitivity of the metal layer to mechanical stress, as well as poor adhesion of the metal to the paper surface, poor smoothness, and high porosity of the paper material. Mechanical stress, for example, can easily result in the loss of the necessary barrier properties that the metallized packaging material is intended to provide. Mechanical stress can result from the processing of multilayer materials in the manufacture of packages, for example, using form-fill-seal packaging machines. During manufacturing, materials are stretched, bent, rolled, compressed, and / or heated during the formation and sealing of packages by conventional package formation methods. These packaging manufacturing processes impose high mechanical and / or chemical stresses on the materials, particularly ultra-thin metallized layers of metal or metalloid, resulting in the development of largely irreversible damage, cracks, and tears in these layers.

[0012] In view of the above, there is a need for a metallized paper-based multi-layer packaging material that simultaneously exhibits the following properties: sufficient barrier properties, particularly barrier properties to oxygen and moisture; high resilience to mechanical stresses, such that the material maintains the same level of barrier even when subjected to transforming processes, such as those used to manufacture the package; a significantly reduced plastic polymer content compared to the content of cellulosic materials; and, preferably, recyclability in paper recycling processes and / or biodegradability in a variety of environmental conditions, particularly (but not exclusively) in marine environments.

[0013] [Summary of the Invention] The inventors have surprisingly found that by grafting a polypeptide onto an organic oxygen barrier polymer (e.g., via succinic acid or citric acid), for example, by grafting collagen onto polyvinyl alcohol (PVOH), the resilience of the resulting organic barrier layer comprising the graft copolymer is improved, and as a result, the mechanical properties of the entire multilayer packaging material comprising the barrier layer are improved.

[0014] Thus, the inventors have overcome the technical limitations of known multilayer barrier structures and have provided a multilayer structure for packaging that has excellent barrier properties against oxygen and moisture transmission, and resistance to liquid contact from its interior or exterior surfaces, while achieving a high total cellulose fiber content.

[0015] Furthermore, the inventors have succeeded in forming a multilayer structure completely free of polymer layers formed by extrusion lamination and / or adhesive lamination, thereby providing a multilayer structure having a ratio of cellulosic fibers to non-cellulosic materials and an extremely high fiber content. In this structure, the polymer layer easily decomposes during the repulping process due to the water solubility of the pre-coating layer. Furthermore, the relatively high adhesion of the post-metallization (or post-metalloidization) polymer to the metallized layer inhibits fragmentation of the metal layer during repulping, resulting in high fiber purity. Therefore, the resulting structure exhibits excellent repulping performance, produces a high yield of high-quality fiber, and is acceptable for standard paper recycling mills in most countries. Due to the extremely low content of non-cellulosic polymers and vacuum-deposited metallic materials, the entire material of the present invention is easily decomposed, dissolved, and separated in recycling processes designed for cellulosic materials such as paper or cardboard, unlike existing multilayer barrier structures known in the art.

[0016] In one aspect, the present invention provides an oxygen barrier substrate comprising or consisting of a graft copolymer comprising a vinyl alcohol polymer backbone and polypeptide branches. The graft copolymer may be any of those described herein. The oxygen barrier substrate may be a packaging film or coating.

[0017] In one aspect, the present invention provides a packaging material comprising at least one oxygen barrier layer comprising or consisting of a graft copolymer comprising a vinyl alcohol polymer backbone and polypeptide branches. The graft copolymer may be any of those described herein. The packaging material may be a metallized paper-based multilayer packaging material.

[0018] In one embodiment, the present invention provides a metallized paper-based multilayer packaging material (1), comprising: (i) 30 to 120 g / m 2 and (ii) a paper layer (2) having a basis weight in the range of 0.5 to 20 g / m 2 Amount of, preferably 1 to 10 g / m 2 More preferably, the amount is 2 to 8 g / m 2 (iii) at least one inorganic barrier layer (4) selected from the list of metals, metalloids, or combinations thereof, having a thickness of 1 to 100 nm; and (iv) at least one organic heat seal layer (5) comprising a heat sealable polymer, the thickness being 2 to 20 g / m. 2 Amount of 4 to 9 g / m 2 and at least one organic heat-seal layer (5) applied in an amount of

[0019] The inorganic layer may comprise a metal or metalloid selected from the list of aluminum, aluminum oxide (AlOx), or silicon oxide (SiOx), the metal and / or metalloid being deposited by either vacuum deposition or transfer metallization. The heat-seal layer may comprise an acrylic or methacrylic polymer grafted with at least one ionomer, preferably a sodium ionomer. Preferably, the ionomer-grafted acrylic or methacrylic polymer has a molecular weight of 85 to 90 g / mol. Each of the organic layers may be deposited on the adjacent layer by either aqueous dispersion or aqueous solution deposition.

[0020] In some embodiments, the paper layer (2) is covered on its outer surface with an ink layer (6). Preferably, the ink layer is selected from the list of water-based ink, solvent-free ink, or a combination thereof. In some embodiments, the paper layer or ink layer is covered on its outer surface with an outermost layer (7) of overprint varnish (OPV). Preferably, the outermost overprint varnish layer (7) is a styrene acrylic varnish.

[0021] Packaging material: 0.5g / m 2 / day (measured at 23°C and 85% relative humidity), and / or a water vapor transmission rate (WVTR) of less than 0.1 cm 3 / m 2 / day bar (measured at 23°C and 50% RH). The packaging material may have a strain at break under in-plane tensile load of up to 5% in the machine direction of the paper and up to 15% in the cross-machine direction.

[0022] In one aspect, the present invention provides a three-dimensional closed packaging article made from a packaging material according to the present invention, obtained by shaping, filling with an edible product for human or animal consumption and then sealing said packaging material.

[0023] In one aspect, the present invention provides the use of a graft copolymer (as described herein) comprising a vinyl alcohol polymer backbone and polypeptide branches, an oxygen barrier substrate according to the present invention, or a packaging material according to the present invention for packaging an edible product for human or animal consumption.

[0024] In one aspect, the present invention provides a packaged edible product comprising a graft copolymer (as described herein) comprising a vinyl alcohol polymer backbone and polypeptide branches, an oxygen barrier substrate according to the present invention, or a packaging material according to the present invention, filled with an edible product for human or animal consumption.

[0025] In one aspect, the present invention provides a graft copolymer comprising a vinyl alcohol polymer backbone and polypeptide branches.

[0026] Any suitable vinyl alcohol polymer backbone can be used. In some embodiments, the vinyl alcohol polymer backbone is polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), butenediol vinyl alcohol copolymer (BVOH), or a combination thereof. In some preferred embodiments, the vinyl alcohol polymer backbone is polyvinyl alcohol (PVOH). Any suitable polypeptide can be grafted to the vinyl alcohol polymer backbone. In some embodiments, the polypeptide is collagen or a hydrolyzed form thereof. The polypeptide branches can be attached to the vinyl alcohol polymer backbone by any suitable method. The polypeptide branches can be attached to the vinyl alcohol polymer backbone by a linker. In some embodiments, the polypeptide branches are attached to the vinyl alcohol polymer backbone by a polycarboxylic acid or anhydride thereof. In some embodiments, the polypeptide branches are attached to the vinyl alcohol polymer backbone by a tricarboxylic acid or anhydride thereof. In some embodiments, the polypeptide branches are attached to the vinyl alcohol polymer backbone by a tricarboxylic acid selected from one or more of citric acid, isocitric acid, aconitic acid, or tricarballylic acid, or anhydrides thereof. In some embodiments, the polypeptide branches are attached to the vinyl alcohol polymer backbone by citric acid or anhydrides thereof. In some embodiments, the polypeptide branches are attached to the vinyl alcohol polymer backbone by citric acid. In some embodiments, the polypeptide branches are attached to the vinyl alcohol polymer backbone by dicarboxylic acids or anhydrides thereof. In some embodiments, the polypeptide branches are attached to the vinyl alcohol polymer backbone by dicarboxylic acids selected from malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, or sebacic acid, or one or more of their anhydrides. In some embodiments, the polypeptide branches are attached to the vinyl alcohol polymer backbone by succinic acid or anhydrides thereof. In some embodiments, the polypeptide branches are attached to the vinyl alcohol polymer backbone by succinic anhydride.

[0027] In one aspect, the present invention provides a method for grafting a polypeptide onto a vinyl alcohol polymer backbone, the method comprising the steps of: (a) functionalizing a vinyl alcohol polymer with a linker molecule to provide a functionalized vinyl alcohol polymer; and (b) grafting a polypeptide onto the functionalized vinyl alcohol polymer to provide a graft copolymer comprising a vinyl alcohol polymer backbone and polypeptide branches.

[0028] Any suitable vinyl alcohol polymer can be used. In some embodiments, the vinyl alcohol polymer is polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), butenediol vinyl alcohol copolymer (BVOH), or a combination thereof. In some preferred embodiments, the vinyl alcohol polymer is polyvinyl alcohol (PVOH). Any suitable polypeptide may be used. In some embodiments, the polypeptide is collagen or a hydrolyzed form thereof. The vinyl alcohol polymer may be functionalized with any suitable linker molecule. In some embodiments, the linker molecule is a polycarboxylic acid or an anhydride thereof. In some embodiments, the linker molecule is a tricarboxylic acid or an anhydride thereof. In some embodiments, the linker molecule is a tricarboxylic acid selected from one or more of citric acid, isocitric acid, aconitic acid, or tricarballylic acid, or anhydrides thereof. In some embodiments, the linker molecule is citric acid or an anhydride thereof. In some embodiments, the linker molecule is citric acid. In some embodiments, the linker molecule is a dicarboxylic acid or anhydride thereof. In some embodiments, the linker molecule is a dicarboxylic acid selected from one or more of malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, or sebacic acid, or anhydrides thereof. In some embodiments, the linker molecule is succinic acid or anhydride thereof. In some embodiments, the linker molecule is succinic anhydride. Any suitable reaction conditions can be used to functionalize the vinyl alcohol polymer. Preferably, the polycarboxylic acid or anhydride thereof is incubated with a nucleophilic catalyst, and optionally, the nucleophilic catalyst is 4-dimethylaminopyridine (DMAP).

[0029] Any suitable reaction conditions can be used to graft the polypeptide chain onto the vinyl alcohol polymer backbone. Preferably, the polypeptide chain is grafted onto the functionalized vinyl alcohol polymer by a carbodiimide crosslinking reaction. In some embodiments, the carbodiimide crosslinking agent is 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDAC), and optionally, N-hydroxysuccinimide (NHS) is included in the carbodiimide crosslinking reaction.

[0030] In one aspect, the present invention provides a graft copolymer obtained or obtainable by a method according to the present invention.

[0031] In one aspect, the present invention provides a functionalized vinyl alcohol polymer, wherein the functionalized vinyl alcohol polymer is functionalized with a polycarboxylic acid or anhydride thereof.

[0032] In some embodiments, the functionalized vinyl alcohol polymer is functionalized with a tricarboxylic acid or anhydride thereof. In some embodiments, the functionalized vinyl alcohol polymer is functionalized with a tricarboxylic acid selected from citric acid, isocitric acid, aconitic acid, or tricarballylic acid, or one or more of their anhydrides. In some embodiments, the functionalized vinyl alcohol polymer is functionalized with citric acid or anhydride thereof. In some embodiments, the functionalized vinyl alcohol polymer is functionalized with citric acid. In some embodiments, the functionalized vinyl alcohol polymer is functionalized with a dicarboxylic acid or anhydride thereof. In some embodiments, the functionalized vinyl alcohol polymer is functionalized with a dicarboxylic acid selected from malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, or sebacic acid, or one or more of their anhydrides. In some embodiments, the functionalized vinyl alcohol polymer is functionalized with succinic acid or anhydride thereof. In some embodiments, the functionalized vinyl alcohol polymer is functionalized with succinic anhydride. [Brief explanation of the drawings]

[0033] Additional features and advantages of the present invention are described in, or will be apparent from, the following description of the presently preferred embodiments, which proceeds with reference to the drawings. [Figure 1] An example of a reaction scheme for grafting collagen onto polyvinyl alcohol (PVOH) by two-step coupling with succinic anhydride is shown. [Figure 2] The hydrophobicity of the paper coated with the recovered graft copolymer was improved. (A) Change in contact angle over time and (B) percentage change in contact angle with varying amounts of water for uncoated paper (UPM Ref), PVOH-coated paper (UPM PVOH), and PVOH-coated paper with grafted collagen (UPM PVOH-Coll). [Figure 3] Confirming the presence of collagen protein in the recovered graft copolymer. SEM images and EDX measurements: (A) dry PVOH coating, (B) dry PVOH coating with grafted collagen, (C) wet PVOH coating, and graft copolymer with grafted collagen wet PVOH coating. [Figure 4] 1 shows a first embodiment of a multilayer structure according to the invention. [Figure 5] 2 shows a second embodiment of a multilayer structure according to the invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] Various preferred features and embodiments of the present invention will now be described by way of non-limiting example, it being understood that those skilled in the art can combine all features of the invention disclosed herein without departing from the scope of the invention as disclosed.

[0035] It should be noted that as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless otherwise indicated. As used herein, the terms "comprising," "comprises," and "comprised of" are synonymous with "including," "includes," "containing," or "contains" and are all-inclusive, i.e., open-ended, and do not exclude additional, unrecited components, elements, or steps. The terms "comprising," "comprises," and "comprised of" also include the term "consisting of." Numerical ranges are inclusive of the numbers defining the range.

[0036] All publications mentioned herein are incorporated herein by reference. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Any publications cited herein should not be construed as an admission that these publications constitute prior art to the claims appended hereto.

[0037] Graft Copolymer In one aspect, the present invention provides a graft copolymer comprising a vinyl alcohol polymer backbone and polypeptide branches.

[0038] As used herein, a "graft copolymer" can refer to a branched copolymer having one or more polymer branches attached to a main polymer backbone, where the components of the branches are structurally different from the components of the main chain (see, for example, Feng, C., et al., 2011. Chemical Society Reviews, 40(3), pp. 1282-1295). The graft copolymer "backbone" is sometimes referred to as the "main chain," and the graft copolymer "branches" are sometimes referred to as "side chains" or "pendants."

[0039] vinyl alcohol polymer backbone The graft copolymer of the present invention can be referred to as a vinyl alcohol graft copolymer. As used herein, "vinyl alcohol graft copolymer" can refer to a graft copolymer in which the main chain polymer is a vinyl alcohol polymer (see, for example, Kang, H., et al., 2015. Polymer, 70, pp. A1-A16).

[0040] As used herein, "vinyl alcohol polymer" may refer to any polymer that includes vinyl alcohol monomers and may include homopolymers and copolymers. Such polymers may include the following formula:

[0041] [ka]

[0042] Examples of vinyl alcohol polymers include polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), propylene vinyl alcohol copolymer, and butenediol vinyl alcohol copolymer (BVOH). Preferably, the vinyl alcohol polymer backbone is PVOH, EVOH, BVOH, or a combination thereof. In some embodiments, the vinyl alcohol polymer backbone is PVOH, EVOH, or BVOH.

[0043] In some embodiments, the vinyl alcohol polymer backbone is polyvinyl alcohol (PVOH). PVOH, also known as poly(vinyl alcohol), PVA, or PVAl, can be prepared by several methods, such as hydrolysis of polyvinyl acetate (see, e.g., Haweel, CK and Ammar, SH, 2008. Iraqi Journal of Chemical and Petroleum Engineering, 9(1), pp. 15-21). PVOH can have the formula:

[0044] [ka]

[0045] In some embodiments, the vinyl alcohol polymer backbone is ethylene vinyl alcohol (EVOH). EVOH is a copolymer of ethylene and vinyl alcohol and can be prepared by polymerizing ethylene and vinyl acetate to give ethylene vinyl acetate (EVA) copolymer, followed by hydrolysis (see, for example, Mokwena, K. K. and Tang, J., 2012. Critical reviews in food science and nutrition, 52(7), pp. 640-650). EVOH can have the following formula:

[0046] [ka]

[0047] The EVOH may have any suitable ethylene content. For example, EVOH copolymers with a low ethylene content have better gas barrier properties but absorb more water than copolymers with a high ethylene content. Preferably, the ethylene content is 25 mol% to 50 mol%.

[0048] In some embodiments, the vinyl alcohol polymer backbone is butenediol vinyl alcohol copolymer (BVOH). BVOH is a copolymer of butenediol and vinyl alcohol and can be prepared by copolymerizing vinyl acetate and butenediol, followed by hydrolysis. BVOH can have the formula:

[0049] [ka]

[0050] The graft copolymers of the present invention may be in the form of a polyvinyl alcohol film, coating, or resin.

[0051] Polypeptide Branching In the graft copolymers of the present invention, the graft polymer branches are polypeptides.

[0052] As used herein, "polypeptide" can refer to multiple amino acid residues linked by peptide bonds. Preferably, the polypeptide is at least about 10 amino acids, at least about 15 amino acids, or at least about 20 amino acids in length. Any suitable polypeptide can be grafted onto the scaffold. Preferably, the polypeptide is a water-soluble polypeptide. Preferably, the polypeptide is a fibrous polypeptide or a globular polypeptide. Suitable fibrous polypeptides can include collagen. Suitable globular polypeptides include any type of albumin or globulin. Suitable polypeptides include collagen, ovalbumin, serum albumin, lactoglobulin, or hydrolyzed forms thereof. In some embodiments, the polypeptide is selected from one or more of collagen, ovalbumin, serum albumin, lactoglobulin, or hydrolyzed forms thereof. In a preferred embodiment, the polypeptide is collagen or a hydrolyzed form thereof.

[0053] Collagen is composed of a right-handed bundle of three parallel left-handed polyproline type II (PPII) helices. The tight packing of the PPII helices within this triple helix requires that every third residue be Gly, resulting in a repeat of the XaaYaaGly sequence (where Xaa and Yaa can be any amino acid residue). This repeat occurs in all types of collagen. The amino acids at the Xaa and Yaa positions in collagen are most often (2S)-proline (Pro, 28%) and (2S,4R)-4-hydroxyproline (Hyp, 38%), respectively. ProHypGly is the most common triplet in collagen (10.5%) (see, e.g., Shoulders, MD and Raines, RT, 2009, Annual Review of Biochemistry, 78, p. 929).

[0054] Any suitable source of collagen can be used in the present invention (see, for example, Silvipriya, KS, et al., 2015. Journal of Applied Pharmaceutical Science, 5(3), pp. 123-127). Animal sources include bovine, porcine, and fish. Collagen is primarily found in connective tissues, such as cartilage, bone, tendon, ligament, and skin.

[0055] Any suitable form of hydrolyzed collagen can be used in the present invention (see, for example, Mariod, AA and Fadul, H., 2013. Acta Scientiarum Polonorum Technologia Alimentaria, 12(2), pp. 135-147). Suitable forms of hydrolyzed collagen include gelatin, which is obtained by thermal denaturation of collagen. In some embodiments, the polypeptide branch is gelatin.

[0056] Linker The polypeptide branches may be grafted to the backbone by any suitable coupling chemistry. Preferably, the polypeptide branches are attached to the backbone by a linker. Preferably, the graft copolymer comprises the formula:

[0057] [ka]

[0058] The linker can be any suitable linker, for example, any linker described herein. Preferably, the linker is an aliphatic group (e.g., having 1 to 8 carbon atoms) optionally substituted with one or more functional groups (e.g., one or more alcohol, carboxyl, and / or amide groups), optionally attached to one or more polypeptides, and / or optionally crosslinked to one or more other backbones.

[0059] Preferably, the linker is attached to the backbone by an ester bond (e.g., at the vinyl alcohol group) and to the polypeptide by a peptide bond (e.g., at the N-terminus of the polypeptide). The linker may be derived from a molecule containing two or more carboxylic acid groups (or anhydrides thereof). In this context, "derived from" may mean that before the grafting reaction, the linker is a molecule containing two or more carboxylic acid groups (or anhydrides thereof), and after the grafting reaction, one carboxylic acid group forms an ester bond (e.g., at the vinyl alcohol group) and one carboxylic acid group forms a peptide bond (e.g., at the N-terminus of the polypeptide). Preferably, the graft copolymer comprises the formula:

[0060] [ka]

[0061] A linker may be an aliphatic group (e.g., having 1 to 8 carbon atoms), optionally substituted with one or more functional groups (e.g., one or more alcohol groups), optionally attached to one or more polypeptides, and / or optionally cross-linked to one or more other backbones.

[0062] Molecules containing two or more carboxylic acid groups (or anhydrides thereof) include polycarboxylic acids or anhydrides thereof. As used herein, "polycarboxylic acid" may refer to an organic compound containing two or more carboxyl groups (-COOH), including dicarboxylic acids and tricarboxylic acids. As used herein, "acid anhydride" may refer to an organic compound having two acyl groups bonded to the same oxygen atom, and "carboxylic acid anhydride" may refer to an acid anhydride whose parent acid is a carboxylic acid.

[0063] In some embodiments, the linker is derived from a dicarboxylic acid or anhydride thereof. In some embodiments, the linker is derived from a dicarboxylic acid anhydride. Suitable dicarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, acetylenedicarboxylic acid, glutaconic acid, muconic acid, glutic acid, citraconic acid, mesaconic acid, and itaconic acid. Suitable dicarboxylic acid anhydrides include malonic anhydride, succinic anhydride, glutaric anhydride, adipic anhydride, pimelic anhydride, suberic anhydride, azelaic anhydride, sebacic anhydride, maleic anhydride, glutaconic anhydride, muconic anhydride, citraconic anhydride, mesaconic anhydride, and itaconic anhydride. Preferably, the graft copolymer comprises the formula:

[0064] [ka]

[0065] R may be an aliphatic group (e.g., having 1 to 8 carbon atoms) optionally substituted with one or more functional groups (e.g., one or more alcohol groups). In some embodiments, R is an aliphatic group having 1 to 8 carbon atoms. In some embodiments, R is an aliphatic group having 2 to 4 carbon atoms. In some embodiments, R is an aliphatic group having 2 to 3 carbon atoms.

[0066] In some embodiments, the linker is derived from succinic acid or its anhydride. In some embodiments, the linker is derived from succinic anhydride. Suitably, the graft copolymer comprises the formula:

[0067] [ka]

[0068] In some embodiments, the linker is derived from a tricarboxylic acid or anhydride thereof. In some embodiments, the linker is derived from a tricarboxylic acid. Suitable tricarboxylic acids include citric acid, isocitric acid, cis-aconitic acid, trans-aconitic acid, and tricarballylic acid. Suitable tricarboxylic acid anhydrides include citric acid anhydride, citric acid 1,5-anhydride, isocitric acid anhydride, cis-aconitic acid anhydride, trans-aconitic acid anhydride, and tricarballylic acid anhydride.

[0069] Compared to dicarboxylic acids or their anhydrides, tricarboxylic acids or their anhydrides may have the advantage of allowing for further branching, for example, by (i) linking two polypeptides and / or (ii) cross-linking the backbone to another. Suitably, the graft copolymer comprises the formula:

[0070] [ka]

[0071] R may be an aliphatic group (e.g., having 1 to 8 carbon atoms) optionally substituted with one or more functional groups (e.g., one or more alcohol groups). In some embodiments, R is an aliphatic group having 1 to 8 carbon atoms, optionally substituted with one or more alcohol groups. In some embodiments, R is an aliphatic group having 3 to 5 carbon atoms, optionally substituted with one or more alcohol groups. In some embodiments, R is an aliphatic group having 3 to 4 carbon atoms, optionally substituted with one or more alcohol groups. In some embodiments, R is an aliphatic group substituted with an alcohol group.

[0072] In some embodiments, the linker is derived from citric acid or its anhydride. In some embodiments, the linker is derived from citric acid. Suitably, the graft copolymer comprises the formula:

[0073] [ka]

[0074] Method for grafting polypeptides onto vinyl alcohol polymers In one embodiment, the present invention provides a method for grafting a polypeptide onto a vinyl alcohol polymer backbone.

[0075] The "grafting onto" or "grafting onto" method can involve the use of a backbone with functional groups randomly distributed along the chain. The formation of the graft copolymer results from a coupling reaction between the functionalized backbone and the reactive end groups of the branches. These coupling reactions can be made possible by chemically modifying the backbone, thereby functionalizing it.

[0076] The method of the present invention may comprise the steps of (a) functionalizing a vinyl alcohol polymer; and (b) grafting a polypeptide onto the functionalized vinyl alcohol polymer. Any suitable reaction conditions may be used to carry out steps (a) and (b). Suitable reaction conditions are described below.

[0077] Step (a): Backbone functionalization Any suitable method can be used to functionalize the backbone. For example, step (a) may include functionalizing the backbone with a linker molecule to provide a functionalized backbone. In one aspect, the present invention provides a functionalized backbone obtained or obtainable by step (a). In some embodiments, the functionalized backbone comprises a carboxylic acid functional group.

[0078] The linker molecule can be any suitable linker molecule, for example, any linker molecule described herein. The linker molecule can include two or more carboxylic acid groups (or anhydrides thereof). Preferably, the functionalized backbone includes the formula:

[0079] [ka]

[0080] The linker may be an aliphatic group (e.g., having 1 to 8 carbon atoms) optionally substituted with one or more functional groups (e.g., one or more alcohol groups) and optionally crosslinked to one or more other backbones.

[0081] In some embodiments, the linker molecule is a dicarboxylic acid or anhydride thereof. In some embodiments, the linker molecule is a dicarboxylic acid anhydride. Suitable dicarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, acetylenedicarboxylic acid, glutaconic acid, muconic acid, glutic acid, citraconic acid, mesaconic acid, and itaconic acid. Suitable dicarboxylic acid anhydrides include malonic anhydride, succinic anhydride, glutaric anhydride, adipic anhydride, pimelic anhydride, suberic anhydride, azelaic anhydride, sebacic anhydride, maleic anhydride, glutaconic anhydride, muconic anhydride, citraconic anhydride, mesaconic anhydride, and itaconic anhydride. Preferably, the functionalized backbone comprises the formula:

[0082] [ka]

[0083] R may be an aliphatic group (e.g., having 1 to 8 carbon atoms) optionally substituted with one or more functional groups (e.g., one or more alcohol groups). In some embodiments, R is an aliphatic group having 1 to 8 carbon atoms. In some embodiments, R is an aliphatic group having 2 to 4 carbon atoms. In some embodiments, R is an aliphatic group having 2 to 3 carbon atoms.

[0084] In some embodiments, the linker molecule is succinic acid or anhydride thereof. In some embodiments, the linker molecule is succinic anhydride. Preferably, the functionalized backbone comprises the formula:

[0085] [ka]

[0086] In some embodiments, the linker molecule is a tricarboxylic acid or anhydride thereof. In some embodiments, the linker molecule is a tricarboxylic acid. Suitable tricarboxylic acids include citric acid, isocitric acid, cis-aconitic acid, trans-aconitic acid, and tricarballylic acid. Suitable tricarboxylic acid anhydrides include citric acid anhydride, citric acid 1,5-anhydride, isocitric acid anhydride, cis-aconitic acid anhydride, trans-aconitic acid anhydride, and tricarballylic acid anhydride. Preferably, the functionalized backbone comprises the formula:

[0087] [ka]

[0088] R may be an aliphatic group (e.g., having 1 to 8 carbon atoms) optionally substituted with one or more functional groups (e.g., one or more alcohol groups). In some embodiments, R is an aliphatic group having 1 to 8 carbon atoms optionally substituted with one or more alcohol groups. In some embodiments, R is an aliphatic group having 3 to 5 carbon atoms optionally substituted with one or more alcohol groups. In some embodiments, R is an aliphatic group having 3 to 4 carbon atoms optionally substituted with one or more alcohol groups. In some embodiments, R is an aliphatic group substituted with one alcohol group.

[0089] In some embodiments, the linker molecule is citric acid or anhydride thereof. In some embodiments, the linker molecule is citric acid. Preferably, the functionalized backbone comprises the formula:

[0090] [ka]

[0091] Preferably, the linker molecule is present in the reaction mixture in an amount of at least 0.5 equivalents, at least 1.0 equivalents, or at least 1.5 equivalents. Preferably, the linker molecule is present in the reaction mixture in an amount of 10.0 equivalents or less, 5.0 equivalents or less, or 4.0 equivalents or less. Preferably, the linker molecule is present in the reaction mixture in an amount of 0.5 to 10.0 equivalents, 1.0 to 5.0 equivalents, or 1.5 to 4.0 equivalents.

[0092] The linker molecule can be coupled to the backbone under any suitable reaction conditions. For example, if the reaction is an esterification reaction, the reaction can be carried out in the presence of a catalyst and heat. Preferably, the reaction mixture contains a nucleophilic catalyst, such as 4-dimethylaminopyridine (DMAP). Preferably, the nucleophilic catalyst (e.g., DMAP) can be added in an amount of 0.1 equivalents. Preferably, the reaction can be carried out at 95°C for 24 hours. For example, if the reaction uses a primary alcohol and a dicarboxylic acid, N-hydroxysuccinimide (NHS) or its water-soluble analog, sulfo-NHS, can be included to activate the carboxylic acid group.

[0093] Any suitable method known in the art can be used to follow the progress of the reaction and / or to confirm that a functionalized scaffold has been obtained. Suitably, infrared (IR) spectroscopy, such as Fourier transform infrared (FT-IR) spectroscopy, can be used to confirm that a functionalized scaffold has been obtained. For example, functionalization with a carboxylic acid can be confirmed by the presence of a 1650 cm -1 Alternatively, solid state NMR can be used to confirm that a functionalized scaffold has been obtained.

[0094] Step (b): Grafting of the polypeptide onto the functionalized backbone Any suitable method can be used to graft the polypeptide onto the functionalized backbone. In one aspect, the present invention provides a graft copolymer obtained or obtainable by step (b).

[0095] For example, if the functionalized backbone contains carboxylic acid functional groups, the polypeptide may be grafted onto the functionalized backbone via a carboxyl-reactive crosslinking reaction, such as a carbodiimide crosslinking reaction. Any suitable carbodiimide crosslinker, such as 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDAC) or N,N'-dicyclohexylcarbodiimide (DCC), may be used. EDAC reacts with carboxylic acid groups to form an active O-acylisourea intermediate that is easily displaced by nucleophilic attack from primary amine groups in the reaction mixture. The primary amine forms an amide bond with the original carboxyl group, releasing the EDAC by-product as a soluble urea derivative. Preferably, EDAC is added to the reaction mixture in an amount of 0.5 equivalents.

[0096] Any suitable reaction conditions can be used. For example, N-hydroxysuccinimide (NHS) or its water-soluble analog sulfo-NHS can be included in the carbodiimide coupling reaction to improve efficiency or generate an amine-reactive intermediate. EDAC couples NHS to the carboxyl to form an NHS ester, which is significantly more stable than the O-acylisourea intermediate, while allowing for efficient conjugation to primary amines. Preferably, NHS can be added to the reaction mixture in an amount of 1.5 equivalents. A base can also be added to the reaction mixture, for example, to deprotonate the carboxylic acid. For example, triethylamine (TEA) can be added to the reaction mixture in an amount of 0.1 equivalents. Preferably, the reaction can be carried out at 95°C for 24 hours.

[0097] Any suitable method known in the art can be used to monitor the progress of the reaction and / or to confirm that a graft copolymer has been obtained. Preferably, infrared (IR) spectroscopy, such as Fourier transform infrared (FT-IR) spectroscopy, can be used to confirm that a graft copolymer has been obtained. For example, grafting with a polypeptide via an amide bond can be confirmed by observing a peak at 1650 cm in the IR spectrum. -1 , 1550cm -1 and 1420 cm -1The presence of amide stretches in the graft copolymer can be confirmed by monitoring the appearance of amide stretches in the graft copolymer. Alternatively, solid-state NMR can be used to confirm that a graft copolymer has been obtained. Alternatively, the Kjeldahl method can be used to confirm that the graft copolymer contains polypeptide branches (see, for example, Bradstreet, RB, 1954, Analytical Chemistry, 26(1), pp. 185-187).

[0098] Oxygen Barrier Substrate In one aspect, the present invention provides an oxygen barrier substrate comprising or consisting of the graft copolymer of the present invention, or the graft copolymer obtained or obtainable by the process of the present invention.

[0099] As used herein, an "oxygen barrier substrate" is a substrate having limited oxygen permeability, e.g., less than 0.1 cm 3 / m 2 Oxygen barrier may refer to a material having an oxygen transmission rate (OTR) of less than 1 / day bar (measured at 23°C and 50% RH). Oxygen barrier substrates can be used to manufacture articles or substances, such as packaging materials. In some embodiments, the oxygen barrier substrate is a film, coating, or resin. In some embodiments, the oxygen barrier substrate is a packaging film or packaging coating.

[0100] Suitably, the oxygen barrier substrate comprises the graft copolymer of the present invention, or the graft copolymer obtained or obtainable by the process herein, in an amount of at least 10 wt%, at least 20 wt%, at least 30 wt%, at least 40 wt%, at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, or at least 90 wt%.

[0101] packaging material In one aspect, the present invention provides a packaging material comprising a graft copolymer of the present invention, a graft copolymer obtained or obtainable by a method of the present invention, or an oxygen barrier substrate of the present invention.

[0102] The packaging material may comprise at least one oxygen barrier layer comprising or consisting of the graft copolymer of the present invention, the graft copolymer obtained or obtainable by the method of the present invention, or the cellulosic substrate of the present invention.

[0103] As used herein, "packaging material" may refer to any article or substance that is intended to come into contact with, or that may come into contact with, an edible product for human or animal consumption, and includes containers, such as cartons, boxes, and cases, or wrapping and covering materials, such as coated paper.

[0104] The present invention further relates to a three-dimensional sealed packaging article made from the packaging material described herein (e.g., the metallized paper-based multilayer packaging material described herein), obtained by shaping, then filling with an edible product for human or animal consumption, and then sealing the packaging material.

[0105] The present invention further relates to the use of packaging materials described herein (e.g., metallized paper-based multi-layer packaging materials described herein) to package edible products for human or animal consumption.

[0106] The present invention further relates to a packaged edible product comprising a packaging material described herein (e.g., a metallized paper-based multilayer packaging material described herein), filled with a food product or an edible product for animal consumption. Preferably, the edible product is a powder, gel, or kibble selected from the following list: soluble coffee, nutritional compositions for infant, adult, or elderly consumption, soup, confectionery or candy, chocolate-based products, dry animal food, dairy products.

[0107] Metallized paper-based multilayer packaging material In a preferred embodiment, the packaging material is a metallized paper-based multilayer packaging material. A "metallized paper-based multilayer packaging material" may comprise a paper layer, a pre-metallization coating layer, a metal coating layer, and a coating layer that is inner than the metal coating.

[0108] The paper layer is 30 to 120 g / m 2 Any suitable cellulosic substrate can be used for the paper layer.

[0109] The coating layer that is outer than the metal coating may comprise or consist of at least one organic barrier layer comprising or consisting of a graft copolymer according to the invention, a graft copolymer obtained or obtainable by a method according to the invention, or an oxygen barrier substrate of the invention. The at least one organic barrier layer may have a thickness of 0.5 to 20 g / m 2 Amount of, preferably 1 to 10 g / m 2 More preferably, the amount is 2 to 8 g / m 2 Preferably, the at least one organic barrier layer comprises the graft copolymer of the present invention, or the graft copolymer obtained or obtainable by the process of the present invention, in an amount of at least 10 wt%, at least 20 wt%, at least 30 wt%, at least 40 wt%, at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, or at least 90 wt%. Preferably, the at least one organic barrier layer comprising the graft copolymer of the present invention, or the graft copolymer obtained or obtainable by the process of the present invention, is present in an amount of from 0.5 to 20 g / m 2 Amount of, preferably 1 to 10 g / m 2 More preferably, the amount is 2 to 8 g / m 2 is present in an amount of

[0110] The metallization layer may comprise or consist of at least one inorganic barrier layer selected from the list of metals, metalloids, or combinations thereof. The metallization layer may have a thickness of 1 to 100 nm. In a preferred embodiment, the at least one inorganic barrier layer comprises a metal or metalloid selected from the list of aluminum, aluminum oxide (AlOx), or silicon oxide (SiOx). The metal and / or metalloid may be deposited by either vacuum evaporation or transfer metallization. In a particularly preferred embodiment, the at least one inorganic barrier layer is a vacuum-deposited layer of aluminum.

[0111] The coating layer that is inner than the metal coating may comprise or consist of at least one organic heat seal layer comprising a heat sealable polymer. The at least one organic heat seal layer has a density of 2 to 20 g / m 2 Amount of 4 to 9 g / m 2 may be present in an amount of

[0112] Each of the organic layers is preferably deposited onto the adjacent layer either by aqueous dispersion or by aqueous solution deposition.

[0113] In a preferred embodiment, the metallized paper-based multilayer packaging material comprises, from the outside to the inside, 30~120g / m 2 a paper layer having a basis weight falling within the range 0.5~20g / m 2 Amount of, preferably 1 to 10 g / m 2 More preferably, the amount is 2 to 8 g / m 2 at least one organic barrier layer comprising or consisting of a graft copolymer according to the present invention in an amount of at least one inorganic barrier layer selected from the list of metals, metalloids, or combinations thereof, having a thickness in the range of 1 to 100 nm; At least one organic heat-sealable layer comprising a heat-sealable polymer, having a density of 2 to 20 g / m 2 An amount falling within the range of 4 to 9 g / m 2 at least one organic heat seal layer applied in an amount falling within the range of Equipped with.

[0114] In all of the embodiments of the present invention described herein, the multilayer structure may include other additional layers and optional layers not described in full detail in such a structure. Such layers may include, for example, a printing layer on the outer surface of the paper layer, and optionally, a protective layer deposited on the outside of the printing layer, thus constituting the outermost layer of the entire structure. The printing layer and optional protective layer are well known to those skilled in the art and will not be described in further detail.

[0115] In some embodiments, the paper layer is covered on its outer surface with an ink layer. The ink layer has a density of 0.5 to 5 g / m 2 In a preferred embodiment, the ink layer is selected from the list of water-based inks, solvent-free inks, or a combination thereof.

[0116] More preferably, the outer surface of the paper layer or ink layer is covered with an outermost layer of overprint varnish (OPV). The OPV layer has a thickness of 0.5 to 10 g / m 2 The optional OPV layer, if present, may also contribute to improving the barrier paper's resistance to hygroexpansive strain, particularly by improving the barrier to moisture (water vapor transmission rate or "WVTR") under humid conditions. In an advantageous embodiment, the outermost overprint varnish layer is a styrene acrylic varnish.

[0117] The metallized paper-based multi-layer packaging material according to the present invention advantageously achieves a barrier to oxygen and moisture of: 0.5 g / m 2 / day (measured at 23°C and 85% relative humidity), and / or a water vapor transmission rate (WVTR) of less than 0.1 cm 3 / m 2 Oxygen transmission rate (OTR) of less than / day bar (measured at 23°C and 50% RH). These values ​​are measured according to flexibility testing standard ASTM F392 or equivalent after subjecting the sample to an in-plane tensile pre-strain of up to 2% and after subjecting the sample to three cycles in a Gelboflex testing apparatus.

[0118] The metallized paper-based multilayer packaging material according to the present invention preferably has a strain at break under in-plane tensile load of up to 5% in the machine direction of the paper and up to 15% in the cross-machine direction, with the overall paper structure having a strain at break of 2.5% in the machine direction and 9% in the cross-machine direction, providing high mechanical recovery.

[0119] The multi-layer structure according to the present invention is preferably designed to be suitable for recycling in standard recycled paper stream processes as well, in accordance with most local or national paper recycling regulations. Recyclability in paper stream processes is achieved by the multi-layer structure according to the present invention, wherein: The fiber content is significant compared to all the raw materials in the structure (the definition of recyclability in paper recycling processes varies depending on national legislation, but on average a material must contain at least 80% fiber to be accepted in paper-specific recycling processes), and The inorganic layer is ultrathin (i.e., a few nanometers, typically 1-100 nm) and consists of a few atoms in thickness. All organic polymer layers are deposited by aqueous dispersion or aqueous solution deposition coating, which means that the layers thus obtained are sufficiently thin relative to the thickness of the paper to achieve a very high paper content throughout the structure, making the entire structure compatible with the paper recycling process described herein; The organic barrier layer preferably comprises a water-soluble polymer (i.e., PVOH, EVOH and / or BVOH), which makes it easier to separate the fibers from the rest of the material of the structure, especially from the cellulosic contents.

[0120] A first embodiment of the present invention is shown in Figure 4. In this embodiment, a multi-layer structure 1 has, from its outer side (i.e., the side of the material facing the outside of a package made from the structure) to its inner side (i.e., the side that comes into contact with a product packaged in a package made from the structure), Optional basis weight 62g / m 2 2, a very smooth paper layer; Mainly provides gas (especially oxygen) barrier properties, optionally 3 g / m 2 a first organic vinyl alcohol polymer-based coating layer 3 outer than the metal coating, the first organic vinyl alcohol polymer-based coating layer 3 comprising or consisting of a graft copolymer of the present invention, a graft copolymer obtained or obtainable by the method of the present invention, or an oxygen barrier substrate of the present invention, applied as an aqueous solution of an inorganic vacuum deposited layer 4 of aluminum, optionally having a thickness of 40 nm, which primarily provides water vapor barrier properties; and 5 g / m 2 a second organic coating layer 5 of a methacrylic acid ionomer based coating applied as an aqueous dispersion of Equipped with.

[0121] In this first embodiment, the deposition techniques for the first and second organic layers as described above allow for improved recyclability of said layers in the paper recycling process. The structure 1 of this first embodiment has an oxygen transmission rate (OTR) value of 0.5 cm, measured at 23°C and 50% relative humidity (RH). 3 / m 2 / day and a water vapor transmission rate (WVTR) of 0.5 g / m2 measured at 23°C and 85% RH 2 / day or less, high moisture barrier property and gas barrier property can be achieved.

[0122] The strain at break for the entire structure 1 can be measured as 2.5% in the machine direction and 9% in the cross-machine direction. These values ​​provide excellent recovery properties that allow the aluminum layer to be protected during processing of the structure in conventional package formation processes. When manufacturing packages from the material, the aluminum layer does not crack while bending, stretching, and / or sealing the material, resulting in comparable OTR and WVTR barrier levels being maintained before and after the package is formed from the multilayer structure material.

[0123] Figure 5 shows a similar structure to that described above in relation to Figure 4. However, in this second exemplary embodiment of the invention, the outer surface of the paper layer 2 is inwardly bounded by: Optionally 1g / m 2 an outermost layer 7 of acrylic overprint varnish applied as an aqueous dispersion of Optionally 1g / m 2 water-based ink 6, applied as an aqueous dispersion of The water-based ink layer 6 is located between the outermost overprint varnish layer 7 and the paper layer 2.

[0124] The remaining layers of Structure 1 remain similar to the structure described with reference to FIG. Optional basis weight 62g / m 2 2, a very smooth paper layer; Mainly provides gas (especially oxygen) barrier properties, optionally 3 g / m 2 a first organic vinyl alcohol polymer-based coating layer 3 outer than the metal coating, the first organic vinyl alcohol polymer-based coating layer 3 comprising or consisting of a graft copolymer of the present invention, a graft copolymer obtained or obtainable by the method of the present invention, or an oxygen barrier substrate of the present invention, applied as an aqueous solution of an inorganic vacuum deposited layer 4 of aluminum, optionally having a thickness of 40 nm, which primarily provides water vapor barrier properties; and Optionally 5g / m2 and a second organic coating layer 5 of a methacrylic acid ionomer based coating applied as an aqueous dispersion of 1000 ppm by weight.

[0125] Structures corresponding to the above embodiments meet the requirements for recyclability of such materials or packaging made from such materials in standard paper recycling mill conditions.

[0126] Method for manufacturing metallized paper-based multilayer packaging material Generally, as used herein, "extrusion coating" refers to a method of applying a layer of polymer by using an extruder to force a molten thermoplastic resin (e.g., polyethylene) through a horizontal slot die onto a moving web of substrate (e.g., paper). The product is a permanently coated web structure.

[0127] "Extrusion lamination" refers to a process akin to extrusion coating in which a polymer resin is extruded between two substrates (eg, a layer of paper and another layer of polymer film) to act as a binder.

[0128] "Adhesive lamination" refers to a process in which one paper material is coated with an adhesive and laminated to a second paper or paperboard material. In the lamination process, two thick layers of material are combined by either extrusion lamination or adhesive lamination, resulting in a thickness of each layer that is much greater than that achieved by dispersion coating.

[0129] "Dispersion coating" refers to a coating technique in which an aqueous dispersion of fine polymer particles or a polymer solution is applied directly to the surface of paper or paperboard to form a solid, nonporous film after drying. Dispersion coating can be performed by gravure, flexogravure, rod, blade, slot die, curtain air knife, roll coating, or any other known paper coating method. Because the polymer is mixed into an aqueous solution, dispersion coating can produce much thinner layers than extrusion lamination and / or adhesive lamination. This offers advantages in terms of polymer usage, its barrier performance, and the recyclability of the resulting paper structure. The goal of dispersion coating is to provide a barrier layer against water, water vapor, grease, oil, gas, etc., using an environmentally friendly coating. Another goal is to prepare the surface of the paper material for vacuum deposition processes. [Example]

[0130] The present invention will now be further described by way of examples, which are meant to be provided to aid those skilled in the art in practicing the invention and are not intended to limit the scope of the invention in any way.

[0131] Example 1: Grafting of collagen onto polyvinyl alcohol (PVOH) via a succinic acid linker The grafting of collagen onto polyvinyl alcohol (PVOH) is carried out via a two-step reaction (see reaction scheme in Figure 1).

[0132] The first step involves functionalizing PVOH with a carboxylic acid spacer by grafting succinic anhydride. 4-Dimethylaminopyridine (DMAP) is used to partially deprotonate the PVOH hydroxyl groups, which then attack the carbonyl group of the anhydride, opening the ring and releasing the carboxylic acid. IR spectra were taken and showed a peak at 1650 cm. -1 The first stage of the reaction can be monitored by following the increase in the carboxylic acid signal in HCl. For completion, the reaction is left overnight.

[0133] The carboxylic acid is then activated using a carbodiimide crosslinker, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDAC), and N-hydroxysuccinimide (NHS), to allow grafting at the N-terminus of collagen. The collagen grafting is observed in the IR spectrum at 1650 cm. -1 , 1550cm -1 and 1420 cm -1 The reaction is monitored by observing the appearance of an amide bond stretch in the reaction mixture. The reaction is left overnight.

[0134] More specifically, 1 g of PVOH (0.00227 mol based on the CH2-CH(OH)- repeating unit) and 50 mL of water were added to a 100 mL round-bottom flask. The solution was heated at 95 °C for 1 hour to dissolve the PVOH. Dimethylaminopyridine (DMAP) (0.227 g, 0.1 equivalents) was added to the solution and stirred for 15 minutes. 3.4 g (1.5 equivalents) of succinic anhydride was then added and the solution was stirred overnight. The reaction was monitored using FTIR. The next morning, the solution was cooled and precipitated in acetone. Three cycles of acetone washing and centrifugation were performed, followed by a drying process. The resulting solid was added to a 50 mL round-bottom flask with 30 mL of water and heated at 95 °C until completely dissolved. EDAC, NHS, and then Et3N were added and stirred for 2 minutes. After that, the collagen solution was added and the reaction was left overnight. The reaction mixture was then cooled, precipitated in acetone, filtered, thoroughly washed, and dried. The resulting solid was analyzed by FT IR.

[0135] The resulting material exhibits higher swelling properties compared to unmodified PVOH: unmodified PVOH has a swelling capacity of 168% (i.e., it absorbs 68% of its weight in water), while the PVOH graft copolymer has a swelling capacity of 636% (i.e., it adsorbs 536% of its weight in water).

[0136] The resulting material also provides a more hydrophobic coating compared to unmodified PVOH. 2Paper with a basis weight of 0.01 mm was coated with the recovered PVOH graft copolymer. Monitoring the contact angle over time revealed that in the presence of collagen, the adsorption of water droplets (as observed by a decrease in the contact angle over time) was slower compared to the reference paper (see Figure 2A). This was confirmed when different volumes of water were applied (see Figure 2B). Systematically, in the presence of the grafted collagen, the contact slope as a function of time was smaller, suggesting less water adsorption, and therefore, that the increased hydrophobicity of the paper was imparted by water adsorption by the collagen on the resulting material, rather than by the paper itself.

[0137] The grafting of collagen onto PVOH was further evidenced by EDX measurements (see Figure 3A-B). This revealed a higher nitrogen content compared to the PVOH reference, confirming the presence of collagen protein. Addition of a water droplet to the sample resulted in swelling of the sample (see Figure 3C-D). As can be seen in the SEM images, after wetting, a swelling effect was observed on the surface of the sample, whereas the reference material showed cracks.

[0138] Thus, the material of the present invention provides a resilient barrier on paper that does not break when water is applied and then dried.

[0139] Embodiment Various preferred features and embodiments of the present invention are described with reference to the following numbered paragraphs.

[0140] 1. A graft copolymer comprising a vinyl alcohol polymer backbone and polypeptide branches.

[0141] 2. The graft copolymer of paragraph 1, wherein the vinyl alcohol polymer backbone is polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), butenediol vinyl alcohol copolymer (BVOH), or a combination thereof.

[0142] 3. The graft copolymer of paragraph 1 or 2, wherein the vinyl alcohol polymer backbone is polyvinyl alcohol (PVOH).

[0143] 4. The graft copolymer of any one of paragraphs 1 to 3, wherein the polypeptide is collagen or a hydrolyzed form thereof.

[0144] 5. The graft copolymer of any one of paragraphs 1-4, wherein the polypeptide branches are attached to the vinyl alcohol polymer backbone by linkers, and optionally the graft copolymer comprises the formula:

[0145] [ka]

[0146] 6. The graft copolymer of any one of paragraphs 1-5, wherein the polypeptide branches are attached to the vinyl alcohol polymer backbone by polycarboxylic acids or anhydrides thereof, and optionally the graft copolymer comprises the formula:

[0147] [ka]

[0148] 7. The graft copolymer of any one of paragraphs 1-6, wherein the polypeptide branches are attached to the vinyl alcohol polymer backbone by tricarboxylic acids or anhydrides thereof, and optionally the polypeptide branches are attached to the vinyl alcohol polymer backbone by tricarboxylic acids selected from one or more of citric acid, isocitric acid, aconitic acid, or tricarballylic acid, or anhydrides thereof.

[0149] 8. The graft copolymer of paragraph 5, wherein the polypeptide branches are attached to the vinyl alcohol polymer backbone by citric acid or anhydride, preferably wherein the polypeptide branches are attached to the vinyl alcohol polymer backbone by citric acid.

[0150] 9. The graft copolymer of any one of paragraphs 1-4, wherein the polypeptide branches are attached to the vinyl alcohol polymer backbone by dicarboxylic acids or anhydrides thereof, and optionally the polypeptide branches are attached to the vinyl alcohol polymer backbone by dicarboxylic acids selected from one or more of malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, or sebacic acid, or anhydrides thereof.

[0151] 10. The graft copolymer of paragraph 7, wherein the polypeptide branches are attached to the vinyl alcohol polymer backbone by succinic acid or anhydride, preferably the polypeptide branches are attached to the vinyl alcohol polymer backbone by succinic anhydride.

[0152] 11. A method for grafting a polypeptide onto a vinyl alcohol polymer backbone, comprising: (a) functionalizing a vinyl alcohol polymer with a linker molecule to provide a functionalized vinyl alcohol polymer; (b) grafting a polypeptide onto the functionalized vinyl alcohol polymer to provide a graft copolymer comprising a vinyl alcohol polymer backbone and polypeptide branches; A method comprising:

[0153] 12. The method of paragraph 11, wherein the vinyl alcohol polymer is polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), or butenediol vinyl alcohol copolymer (BVOH), or a combination thereof.

[0154] 13. The method of paragraph 11 or 12, wherein the vinyl alcohol polymer is polyvinyl alcohol (PVOH).

[0155] 14. The method of any one of paragraphs 11 to 13, wherein the polypeptide is collagen or a hydrolyzed form thereof.

[0156] 15. The method of any one of paragraphs 11 to 14, wherein the linker molecule is a polycarboxylic acid or anhydride thereof, and optionally the functionalized vinyl alcohol polymer comprises the formula:

[0157] [ka]

[0158] 16. The method of any one of paragraphs 11 to 15, wherein the linker molecule is a tricarboxylic acid or an anhydride thereof, optionally wherein the linker molecule is a tricarboxylic acid selected from one or more of citric acid, isocitric acid, aconitic acid, or tricarballylic acid, or anhydrides thereof.

[0159] 17. The method of paragraph 16, wherein the linker molecule is citric acid or anhydride thereof, preferably the linker molecule is citric acid.

[0160] 18. The method of any one of paragraphs 11 to 15, wherein the linker molecule is a dicarboxylic acid or an anhydride thereof, optionally wherein the linker molecule is a dicarboxylic acid selected from one or more of malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, or sebacic acid, or anhydrides thereof.

[0161] 19. The method of paragraph 18, wherein the linker molecule is succinic acid or its anhydride, preferably the linker molecule is succinic anhydride.

[0162] 20. The method of any one of paragraphs 15 to 19, wherein the polycarboxylic acid or anhydride thereof is incubated with a nucleophilic catalyst, and optionally the nucleophilic catalyst is 4-dimethylaminopyridine (DMAP).

[0163] 21. The method of any one of paragraphs 15 to 20, wherein polypeptide chains are grafted onto the functionalized vinyl alcohol polymer by the carbodiimide crosslinking reaction.

[0164] 22. The method of any one of paragraphs 17 to 21, wherein the carbodiimide crosslinking agent is 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDAC), and optionally, N-hydroxysuccinimide (NHS) is included in the carbodiimide crosslinking reaction.

[0165] 23. A graft copolymer obtained or obtainable by the method according to any one of paragraphs 11 to 22.

[0166] 24. Functionalized vinyl alcohol polymers, which are functionalized with polycarboxylic acids or their anhydrides.

[0167] 25. The functionalized vinyl alcohol polymer according to paragraph 24, wherein the functionalized vinyl alcohol polymer is functionalized with a tricarboxylic acid or an anhydride thereof, optionally the functionalized vinyl alcohol polymer is functionalized with a tricarboxylic acid selected from one or more of citric acid, isocitric acid, aconitic acid, or tricarballylic acid, or anhydrides thereof, preferably the functionalized vinyl alcohol polymer is functionalized with citric acid or an anhydride thereof, more preferably the functionalized vinyl alcohol polymer is functionalized with citric acid.

[0168] 26. The functionalized vinyl alcohol polymer according to paragraph 24, wherein said functionalized vinyl alcohol polymer is functionalized with a dicarboxylic acid or anhydride thereof, optionally said functionalized vinyl alcohol polymer is functionalized with a dicarboxylic acid selected from one or more of malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, or sebacic acid, or anhydrides thereof, preferably said functionalized vinyl alcohol polymer is functionalized with succinic acid or anhydride thereof, more preferably said functionalized vinyl alcohol polymer is functionalized with succinic anhydride.

[0169] 27. An oxygen barrier substrate comprising or consisting of a graft copolymer according to any one of paragraphs 1 to 10 or paragraph 23.

[0170] 28. The oxygen barrier substrate according to paragraph 27, wherein the oxygen barrier substrate is a film, a coating, or a resin.

[0171] 29. A packaging material comprising the graft copolymer of any one of paragraphs 1 to 10 or 23, or the oxygen barrier substrate of paragraph 27 or 28.

[0172] 30. The packaging material is a multi-layer metallized paper-based packaging material, and preferably, the multi-layer metallized paper-based packaging material (1) is, from its outside to its inside, (i) 30 to 120 g / m 2 a paper layer (2) having a basis weight in the range of (ii) 0.5 to 20 g / m 2 Amount of, preferably 1 to 10 g / m 2 More preferably, the amount is 2 to 8 g / m 2 at least one organic barrier layer (3) in an amount of (iii) at least one inorganic barrier layer (4) selected from the list of metals, metalloids, or combinations thereof, having a thickness of 1 to 100 nm; (iv) at least one organic heat-sealable layer (5) comprising a heat-sealable polymer, having a density of 2 to 20 g / m 2 Amount of 4 to 9 g / m 2 at least one organic heat seal layer (5) applied in an amount of Equipped with the at least one organic barrier layer comprises or consists of a graft copolymer according to any of paragraphs 1 to 10 or 23, or an oxygen barrier substrate according to paragraph 27 or 28, 29. The packaging material of paragraph 29.

[0173] 31. The metallized paper-based multilayer packaging material (1) according to paragraph 30, wherein the inorganic layer comprises a metal or metalloid selected from the list of aluminum, aluminum oxide (AlOx), or silicon oxide (SiOx), and the metal and / or metalloid is deposited by either vacuum deposition or transfer metallization.

[0174] 32. The multi-layer metallized paper-based packaging material (1) according to paragraph 30 or 31, wherein the heat seal layer comprises an acrylic or methacrylic polymer grafted with at least one ionomer, preferably a sodium ionomer.

[0175] 33. The metallized paper-based multilayer packaging material (1) according to any one of paragraphs 30 to 32, wherein the ionomer-grafted acrylic or methacrylic polymer has a molecular weight of 85 to 90 g / mol.

[0176] 34. The metallized paper-based multi-layer packaging material (1) according to any one of paragraphs 30 to 33, wherein each of the organic layers is deposited on the adjacent layer by either aqueous dispersion or aqueous solution deposition.

[0177] 35. The metallized paper-based multilayer packaging material (1) according to any one of paragraphs 30 to 34, wherein the paper layer (2) is covered on its outer surface with an ink layer (6).

[0178] 36. The metallized paper-based multi-layer packaging material (1) according to paragraph 35, wherein the ink layer is selected from the list of water-based ink, solvent-free ink, or a combination thereof.

[0179] 37. The metallized paper-based multi-layer packaging material (1) according to paragraph 35 or 36, wherein the paper layer or ink layer is covered on its outer surface by an outermost layer (7) of overprint varnish (OPV).

[0180] 38. The metallized paper-based multilayer packaging material (1) according to paragraph 37, wherein the outermost overprint varnish layer (7) is a styrene acrylic varnish.

[0181] 39. Packaging material is 0.5g / m 2 / day (measured at 23°C and 85% relative humidity), and / or a water vapor transmission rate (WVTR) of less than 0.1 cm 3 / m 2 39. The metallized paper-based multilayer packaging material (1) of any one of paragraphs 30 to 38, having an oxygen transmission rate (OTR) of less than 1 / day bar (measured at 23°C and 50% RH).

[0182] 40. The metallized paper-based multilayer packaging material of any one of paragraphs 30 to 39, wherein the packaging material has a strain at break under an in-plane tensile load of up to 5% in the machine direction of the paper and up to 15% in the cross-machine direction.

[0183] 41. A three-dimensional sealed packaging article made of the packaging material of any one of paragraphs 29 to 40, obtained by shaping the packaging material, filling it with an edible product for human or animal consumption, and then sealing it.

[0184] 42. Use of a graft copolymer according to any one of paragraphs 1 to 11 or 23, an oxygen barrier substrate according to paragraph 27 or 28 or a packaging material according to any one of paragraphs 29 to 40 for packaging an edible product for human or animal consumption.

[0185] 43. A packaged edible product comprising a graft copolymer according to any one of paragraphs 1 to 11 or 23, an oxygen barrier substrate according to paragraph 27 or 28, or a packaging material according to any one of paragraphs 29 to 40, filled with an edible product for human or animal consumption.

Claims

1. An oxygen barrier substrate comprising or consisting of a graft copolymer comprising a vinyl alcohol polymer backbone and polypeptide branches.

2. 10. The oxygen barrier substrate of claim 1, wherein the vinyl alcohol polymer backbone is polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), butenediol vinyl alcohol copolymer (BVOH), or a combination thereof, preferably the vinyl alcohol polymer backbone is polyvinyl alcohol (PVOH).

3. 3. The oxygen barrier substrate of claim 1, wherein the polypeptide is collagen or a hydrolyzed form thereof.

4. 4. The oxygen barrier substrate of any one of claims 1 to 3, wherein the polypeptide branches are attached to the vinyl alcohol polymer backbone by linkers, and optionally the graft copolymer comprises the formula: 【Chemistry 1】

5. 5. The oxygen barrier substrate of any one of claims 1 to 4, wherein the polypeptide branches are attached to the vinyl alcohol polymer backbone by polycarboxylic acids or anhydrides thereof, and optionally the graft copolymer comprises the formula: 【Chemistry 2】

6. the polypeptide branch is (a) a tricarboxylic acid or anhydride thereof, optionally wherein the tricarboxylic acid or anhydride thereof is selected from one or more of citric acid, isocitric acid, aconitic acid, or tricarballylic acid, or anhydrides thereof, preferably wherein the tricarboxylic acid or anhydride thereof is citric acid or anhydride, more preferably wherein the tricarboxylic acid or anhydride is citric acid; or (b) a dicarboxylic acid or anhydride thereof, optionally wherein the dicarboxylic acid or anhydride thereof is selected from one or more of malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, or sebacic acid, or anhydrides thereof, preferably wherein the dicarboxylic acid or anhydride thereof is succinic acid or anhydride, more preferably wherein the dicarboxylic acid or anhydride thereof is succinic anhydride; The oxygen barrier substrate according to any one of claims 1 to 5, wherein the vinyl alcohol polymer backbone is bound by

7. A packaging material comprising the oxygen barrier substrate according to any one of claims 1 to 6.

8. The packaging material is a metallized paper-based multilayer packaging material (1), and from the outside to the inside, (i) 30-120g / m ２ a paper layer (2) having a basis weight in the range of (ii) 0.5-20g / m ２ at least one organic barrier layer (3) in an amount of 0.1 wt %, wherein the at least one organic barrier layer comprises or consists of an oxygen barrier substrate according to any one of claims 1 to 6; (iii) at least one inorganic barrier layer (4) selected from the list of metals, metalloids, or combinations thereof, having a thickness of 1 to 100 nm; (iv) at least one organic heat-seal layer (5) comprising a heat-sealable polymer, having a density of 2 to 20 g / m ２ At least one organic heat seal layer (5) applied in an amount comprised in the amount of Equipped with Optionally, each of said organic layers is deposited on the adjacent layer by either aqueous dispersion or aqueous solution deposition; The packaging material of claim 7.

9. 9. The metallized paper-based multilayer packaging material (1) of claim 8, wherein the inorganic barrier layer comprises a metal or metalloid selected in the list of aluminum, aluminum oxide (AlOx), or silicon oxide (SiOx), and wherein the metal and / or metalloid is deposited by either vacuum deposition or transfer metallization.

10. 10. The metallized paper-based multilayer packaging material (1) according to claim 8 or 9, wherein the organic heat-seal layer comprises an acrylic or methacrylic polymer grafted with at least one ionomer, preferably a sodium ionomer, and optionally the ionomer-grafted acrylic or methacrylic polymer has a molecular weight of 85 to 90 g / mol.

11. 11. The metallized paper-based multilayer packaging material (1) according to any one of claims 8 to 10, wherein the paper layer (2) is covered on its outer surface with an ink layer (6), preferably the ink layer is selected from the list of water-based ink, solvent-free ink, or a combination thereof, and optionally the paper layer or the ink layer is covered on its outer surface with an outermost layer (7) of overprint varnish (OPV), preferably the outermost overprint varnish layer (7) is a styrene acrylic varnish.

12. The packaging material (a) 0.5 g / m ２ / day (measured at 23°C and 85% relative humidity), and / or ３ / m ２ / day bar (measured at 23°C and 50% RH), and / or (b) Strain at break under in-plane tensile load of up to 5% in the machine direction of the paper and up to 15% in the cross-machine direction. The metallized paper-based multilayer packaging material (1) according to any one of claims 8 to 11,

13. 13. A three-dimensional sealed packaging article made of the packaging material according to any one of claims 7 to 12, obtained by shaping the packaging material, filling it with an edible product for human or animal consumption and then sealing it.

14. Use of an oxygen barrier substrate according to any one of claims 1 to 6 or a packaging material according to any one of claims 7 to 12 for packaging an edible product for human or animal consumption.

15. A packaged edible product comprising an oxygen barrier substrate according to any one of claims 1 to 6 or a packaging material according to any one of claims 7 to 12 filled with an edible product for human or animal consumption.

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