MODIFIED POLYETHYLENE-BASED POLYMERS AND Edible

Abstract

A polymeric material is provided that includes a modified polyvinyl polymer having a polyvinyl chain including one or more units having a moiety resulting from the reaction of a reactant with polyvinyl alcohol. A method of making a modified polyvinyl polymer includes reacting a polyvinyl alcohol with one or more reactants in the presence of a solvent. The package includes a polymeric material comprising a modified polyvinyl polymer.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 422,801, filed Nov. 4, 2022, the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] This application relates to polymeric materials, including packaging of edibles, and methods of manufacture. BACKGROUND OF THE INVENTION

[0004] Packaging materials are used to contain and protect various objects during storage and transportation. Historically, various materials such as cardboard, plastic, metal, and glass have been used for packaging. However, many packaging materials are deposited in landfills after use. Non-renewable resources such as petroleum have been used to produce conventional plastics. Although plastic-based packaging may be desirable due to its low cost, the packaging materials containing such plastics can persist in the environment for a significant amount of time after being discarded. Some polymer films, such as polyvinyl alcohol (PVOH), can be water-soluble. However, it is suspected that PVOH or its derivatives can persist in the environment even after being dissolved in water.

[0005] In addition, some polymeric materials do not provide sufficient mechanical properties required for specific applications, such as tensile strength, puncture strength, water vapor permeability, and oxygen transmission. For example, although water solubility may be considered beneficial for some applications from a usage perspective, solubility can limit the use of the material as a packaging material for liquid food products or food products with high water activity. In addition, during the desired product shelf life, the pH of liquid or food products can be detrimental to the stability of the packaging material. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 Illustrates an embodiment of a reaction scheme for preparing a modified polyvinyl polymer;

[0007] Figure 2 Illustrates an embodiment of a reaction scheme for preparing a modified polyvinyl polymer via the reaction between polyvinyl alcohol and succinic anhydride;

[0008] Figure 3A 、 3B 、and 3C illustrate various views of an exemplary bag;

[0009] Figure 4 Illustrates an exemplary film;

[0010] Figure 5 、 6, 7, and 8 provide the IR spectra of exemplary polymeric materials.

[0011] The elements in the figures are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions and / or relative positions of some elements in the figures may be exaggerated relative to other elements to help improve understanding of the various embodiments of the present invention. Additionally, elements that are useful or necessary in a commercially viable embodiment and are common and well-known are typically not depicted so as to reduce visual clutter of these different embodiments of the present invention. Certain acts and / or steps may be described or depicted in a particular order of occurrence, but those skilled in the art will understand that no such particularity of order is actually required. The terms and expressions used herein have the ordinary technical meaning ascribed to such terms and expressions by those skilled in the above-mentioned technical field, unless a different specific meaning has been otherwise specified herein. Detailed Description

[0012] Modified polyvinyl polymers useful for preparing packaging materials are provided herein. The modified polyvinyl polymers may include structures derived from one or more biobased components. The modified polyvinyl polymer materials can be formed into various properties and functional performances for different applications. In one specific embodiment, a polymer film can be formed from, or include, one or more modified polyvinyl polymers and can be used to produce food packaging films, including food packaging films for aqueous edibles such as condiments. In one specific aspect, the food packaging is in the form of a capsule or a bag. Also provided are methods for preparing the modified polyvinyl polymers, and various materials containing the modified polyvinyl polymers.

[0013] The modified polyvinyl polymers can be provided in the form of films, laminates, etc. Similarly, the modified polyvinyl polymers can be provided in the form of pellets or other particulate matter and can be used to form polymer films, such as in industrial processes and packaging systems. The packaging can include one or more modified polyvinyl polymers and have specially tailored material properties.

[0014] The modified polyvinyl polymers can be produced by modifying a polyvinyl polymer, such as polyvinyl alcohol, to form new moieties on the polyvinyl chain. In some aspects, the modified polyvinyl polymers include polyvinyl chains that include one or more units containing an ester moiety, which are produced by reacting an acid anhydride reactant with the hydroxyl moieties of polyvinyl alcohol. In other aspects, the modified polyvinyl polymers include polyvinyl chains that include one or more units containing an ether moiety, which are produced by reacting an epoxide reactant with the hydroxyl moieties of polyvinyl alcohol.

[0015] In one approach, a method of forming a modified polyvinyl polymer can include reacting polyvinyl alcohol with one or more reactants to obtain a modified polyvinyl polymer that includes moieties not present in unmodified polyvinyl alcohol. The method can be carried out in a batch or continuous process.

[0016] In some forms, the packaging film can comprise a polymeric material that includes structures derived from one or more biobased components. In some aspects, the packaging optionally includes conventional polymers such as polyethylene, polyethylene terephthalate, and polypropylene. The packaging can include one or more modified polyvinyl polymers. The modified polyvinyl polymer can comprise one or more structures derived from one or more biobased components. The polymeric resin for making the packaging film can include one or more modified polyvinyl polymers and optionally one or more polymers different from the modified polyvinyl polymers. The polymeric resin can generally take any form such as pellets, granulates, films, sheets, flexible packaging, or containers. For example, sheets or films can be formed by extrusion, solution casting, or melt blowing. In some forms, films or sheets can be formed from pellets.

[0017] The modified polyvinyl polymer generally can include a polyvinyl chain that is derived from any polyvinyl polymer, which can be formed from one or more types of vinyl monomers. For example, polyvinyl alcohol can be produced by polymerizing vinyl acetate monomers to form polyvinyl acetate. Subsequently, polyvinyl alcohol can be formed by hydrolyzing the acetate moieties of polyvinyl acetate to hydroxyl moieties. When formed by incomplete hydrolysis, polyvinyl alcohol can retain a certain percentage of acetate moieties. For example, the degree of hydrolysis of various polyvinyl alcohol polymers can be 50% or greater, 60% or greater, 70% or greater, 75% or greater, 80% or greater, 85% or greater, 90% or greater, 91% or greater, 92% or greater, 93% or greater, 94% or greater, 95% or greater, 96% or greater, 97% or greater, 98% or greater, 99% or greater, or the degree of hydrolysis ranges from 70% to 100%, 75% to 99%, 80% to 98%, 85% to 97%, 90% to 96%, 91% to 95%, 93% to 95%, or 92% to 94%. Generally, a degree of hydrolysis of 100% represents polyvinyl alcohol in which 100% of the acetate moieties of polyvinyl acetate have been hydrolyzed to hydroxyl moieties. It is believed that polyvinyl alcohol with a higher degree of hydrolysis has higher water solubility because the proportion of hydroxyl groups present is increased compared to polyvinyl alcohol with a relatively lower degree of hydrolysis. Without wishing to be bound by theory, it is believed that increasing the hydroxyl groups via the hydrolysis process increases the polarity of polyvinyl alcohol and thus increases water solubility. In some forms, the modified polyvinyl polymer includes a polyvinyl chain produced by modifying polyvinyl alcohol.

[0018] Generally, a modified polyvinyl polymer may include polyvinyl chains that contain one or more units that increase the lipophilicity of the polyvinyl polymer. Without wishing to be bound by theory, it is believed that modifying the hydroxyl moiety of the polyvinyl polymer by reaction with an electrophilic molecule can increase the local lipophilicity of a portion of the polyvinyl chain.

[0019] Examples of suitable units that can increase the lipophilicity of the polyvinyl polymer include one or more of the following units: units containing an ester moiety, units containing an ether moiety, units containing a carboxylic acid moiety, and units containing both an ester moiety and a carboxylic acid moiety. In some aspects, the modified polyvinyl polymer may include units in which one or more of the hydroxyl moiety and acetate moiety of polyvinyl alcohol have been altered by one or more reactants.

[0020] In some aspects, the polyvinyl chains of the modified polyvinyl polymer may contain one or more units containing an ester moiety produced by the reaction between an acid anhydride reactant and the hydroxyl groups of polyvinyl alcohol. Generally, the acid anhydride reactant may include any one or more different acid anhydrides. Suitable acid anhydrides may be cyclic or acyclic. The acid anhydride reactant may include one or more of the following: acid anhydrides that do not include unsaturated carbon-carbon bonds, and acid anhydrides that include one or more unsaturated carbon-carbon bonds. The acid anhydride reactant may include one or more of the following: acid anhydrides that do not include carbon-carbon double bonds, and acid anhydrides that include one or more carbon-carbon double bonds. In some aspects, the modified polyvinyl polymer includes polyvinyl chains that contain one or more units containing an ester moiety produced by the reaction of an acid anhydride reactant with the ester bond of the hydroxyl groups on polyvinyl alcohol, wherein the acid anhydride reactant does not include carbon-carbon double bonds. Examples of acid anhydrides that may be included in the acid anhydride reactant include one or more of the following: succinic anhydride, acetic anhydride, propionic anhydride, adipic anhydride, glutaric anhydride, pimelic anhydride, suberic anhydride, malonic anhydride, maleic anhydride, itaconic anhydride, citraconic anhydride, mesaconic anhydride, glutaconic anhydride, and phthalic anhydride.

[0021] Generally, succinic anhydride refers to maleic anhydride. Without wishing to be bound by theory, it is believed that the carbon-carbon double bond in maleic anhydride provides additional reactivity via conjugate addition. This reactivity is in addition to the reactivity between the acid anhydride that produces the ester moiety and the hydroxyl group. Without wishing to be bound by theory, it is believed that the two reaction pathways provided by maleic anhydride can limit control over which reaction pathway predominates by providing less selectivity and make it more difficult to control the properties of the reaction product.

[0022] The acid anhydride can react with the hydroxyl moiety of polyvinyl alcohol to form an ester moiety on the polyvinyl chain. In some forms, the polyvinyl chains of the modified polyvinyl polymer can generally have the following structure, wherein at least a portion of the hydroxyl groups of the polyvinyl alcohol have reacted with the acid anhydride reactant. In other aspects, the polyvinyl chains can generally have the following structure, wherein all or substantially all of the hydroxyl groups of the polyvinyl alcohol have reacted with the acid anhydride reactant.

[0023] It has been observed that succinic anhydride is a compound with relatively low electrophilicity and effectively modifies polyvinyl alcohol. In addition, succinic anhydride can be biobased and is naturally obtained from biobased or non-petroleum sources. For example, succinic anhydride can be present in shrubs such as Clerodendrum japonicum and Pycnandra acuminate. Figure 1 The reaction shown by the downward arrow in depicts an embodiment of the reaction between polyvinyl alcohol and succinic anhydride, and succinic anhydride has the following formula (I):

[0024]

[0025] This reaction produces a capped unit including an ester and a carboxylic acid moiety, as Figure 1 shown in the bottom polyvinyl chain in. Note that Figure 1 the acetate (acetyl ester) moiety is depicted as "OAc" on the polyvinyl chain. Acetate can also be depicted as CH3COO-.

[0026] The modified polyvinyl polymer can generally include the following polyvinyl chains, which contain one or more units containing an ester moiety having the following formula (II):

[0027]

[0028] wherein X represents a divalent group. In formula (II), the divalent group X can generally have 2 to 6 carbon atoms. In some aspects, the polyvinyl chains of the modified polyvinyl polymer can contain one or more units containing an ester moiety having the following formula (III):

[0029]

[0030] As shown in formula (III), the unit including the ester moiety can also include a carboxylic acid moiety.

[0031] It is also believed that the carboxylic acid moiety formed by the reaction of the acid anhydride reactant with polyvinyl alcohol can react with the hydroxyl groups on the polyvinyl chain. By this reaction, it is believed that crosslinking can occur. For example, Figure 2Embodiments of the reaction between succinic anhydride and polyvinyl alcohol are shown. As shown, succinic anhydride initially reacts with the hydroxyl groups of polyvinyl alcohol to form units comprising an ester moiety and a carboxylic acid moiety (depicted as the intermediate product in Figure 2 ). It is believed that the carboxylic acid moiety can further react with additional hydroxyl groups to form crosslinks (shown at the bottom in Figure 2 ). It is generally believed that the crosslinking can occur by reaction of the carboxylic acid moiety with a hydroxyl moiety on the same polyvinyl chain or by reaction of the carboxylic acid with a hydroxyl moiety on a different polyvinyl chain. When the carboxylic acid group crosslinks with the hydroxyl group, an ester and water are formed. Without wishing to be bound by theory, it is generally believed that the formed ester moiety that increases polymer stability remains on the polyvinyl chain. However, the crosslinking process can be reversed since the ester moiety can be hydrolyzed by water. Thus, controlling process conditions can determine the degree of crosslinking in the modified polyvinyl polymer. The modified polyvinyl polymer can generally have any degree of crosslinking. In some aspects, the degree of crosslinking of the units comprising the ester moiety in the modified polyvinyl polymer can range from 70% to 100%, 80% to 99%, 90% to 98%, 91% to 97%, or 92% to 96%. In Figure 2 ,"OAc" represents the acetate (acetyl ester) moiety on the polyvinyl chain.

[0032] In some aspects, the polyvinyl chains of the modified polyvinyl polymer can comprise one or more crosslinking units having the following formula (IV):

[0033]

[0034] In the above formula (IV), X is a divalent group, and the polyvinyl chain of the modified polyvinyl polymer comprises the unit (A) indicated in brackets. The divalent group X can generally have 2 to 6 carbon atoms. In some forms, the polyvinyl chain of the modified polyvinyl polymer comprises both the unit (A) and the unit (B) indicated in brackets. In other forms, the polyvinyl chain of the modified polyvinyl polymer comprises the unit (A), the polyvinyl chain of a separate polymer comprises the unit (B), and the polyvinyl chain of the separate polymer is derived from polyvinyl alcohol. In some aspects, for the crosslinking units of one or more crosslinking units, one of the following conditions is met: the polyvinyl chain of the modified polyvinyl polymer comprises the unit (B), or the polyvinyl chain of a separate polymer comprises the unit (B), and the polyvinyl chain of the separate polymer is derived from polyvinyl alcohol. In some forms, the modified polyvinyl polymer can comprise one or more units according to formula (II) and one or more units according to formula (IV).

[0035] In some aspects, the polyvinyl chains of the modified polyvinyl polymer can comprise one or more crosslinking units having the following formula (V):

[0036]

[0037] In formula (V), the vinyl chain of the modified polyvinyl polymer comprises unit (A) represented by brackets. In some forms, the vinyl chain of the modified polyvinyl polymer comprises both unit (A) and unit (B) indicated by brackets. In other forms, the vinyl chain of the modified polyvinyl polymer comprises unit (A), the vinyl chain of the separate polymer comprises unit (B), and the vinyl chain of the separate polymer is derived from polyvinyl alcohol. In some aspects, for the crosslinking units of one or more crosslinking units, one of the following conditions is satisfied: the vinyl chain of the modified polyvinyl polymer comprises unit (B), or the vinyl chain of the separate polymer comprises unit (B), and the vinyl chain of the separate polymer is derived from polyvinyl alcohol. In some forms, the modified polyvinyl polymer may comprise one or more units according to formula (III) and one or more units according to formula (V).

[0038] In some forms, the modified polyvinyl polymer may comprise a vinyl chain that comprises one or more units containing an ether moiety, which are produced by the reaction between an epoxide reactant and a hydroxyl group of polyvinyl alcohol. The units comprising an ether moiety produced by the reaction between an epoxide reactant and a hydroxyl group of polyvinyl alcohol may further comprise a hydroxyl group. This hydroxyl group may further react with an acetate moiety of polyvinyl alcohol. It is believed that such a reaction may occur via transesterification of the ester bond between the acetate moiety and the hydroxyl group of the capping group.

[0039] Generally, the epoxide reactant may comprise one or more of ethylene oxide, propylene oxide, butylene oxide, and styrene oxide. In one embodiment, the epoxide reactant has the following formula (VI):

[0040]

[0041] wherein R represents a monovalent group comprising from 0 to 6 carbon atoms. Generally, R may be aliphatic or aromatic. Propylene oxide is a compound with relatively low electrophilicity, which effectively modifies polyvinyl alcohol. In some aspects, the modified polyvinyl polymer comprises one or more units containing an ether moiety, which are produced by the reaction between propylene oxide and a hydroxyl group of polyvinyl alcohol.

[0042] The reaction depicted by the upward arrow in Figure 1 shows the reaction between the hydroxyl group of polyvinyl alcohol and propylene oxide, and propylene oxide has the following formula (VII):

[0043]

[0044] The capping group on the left side of the modified polyvinyl polymer ( Figure 1 the uppermost polyvinyl chain therein) is the product of a first reaction between propylene oxide and the hydroxyl moiety of polyvinyl alcohol. The modified capping group in the center of the modified polyvinyl polymer (designated as "second modification") ( Figure 1 the uppermost polyvinyl chain therein) is generated by transesterification between the acetate moiety on the polyvinyl chain and the hydroxyl moiety of the capping group on the same chain. Here, the acetyl moiety has been transferred to the capping group. In some forms, the polyvinyl chains of the modified polyvinyl polymer may generally have the following structure, wherein at least a portion of the hydroxyl groups of the polyvinyl alcohol have reacted with an epoxide reactant. In some aspects, the polyvinyl chains of the modified polyvinyl polymer may have the following structure, wherein all or substantially all of the hydroxyl groups of the polyvinyl alcohol polymer have reacted with an epoxide reactant to form units comprising ether moieties. In some forms, the polyvinyl chains of the modified polyvinyl polymer may have the following structure: wherein at least a portion of the units comprising ether moieties (capping groups formed by the reaction between an epoxide reactant and a hydroxyl moiety) further react by transfer of an acetyl moiety from the polyvinyl chain to the capping group. In some aspects, the polyvinyl chains of the modified polyvinyl polymer may have the following structure: wherein all or substantially all of the units comprising ether moieties (capping groups formed by the reaction between an epoxide reactant and a hydroxyl moiety) further react by transfer of an acetyl moiety from the polyvinyl chain to the capping group.

[0045] The modified polyvinyl polymer may include polyvinyl chains comprising one or more units selected from: units comprising an ester moiety, which are produced by the reaction between an acid anhydride reactant and the hydroxyl groups of polyvinyl alcohol, and units comprising an ether moiety, which are produced by the reaction between an epoxide reactant and the hydroxyl groups of polyvinyl alcohol. In some forms, the modified polyvinyl polymer may include polyvinyl chains that contain one or more units comprising an ester moiety produced by the reaction of an acyl halide (such as an acyl chloride) with the hydroxyl groups of polyvinyl alcohol.

[0046] Generally, the modified polyvinyl polymer may include polyvinyl chains comprising one or more vinyl alcohol units, having the following formula (VIII):

[0047]

[0048] The polyvinyl chains of the modified polyvinyl polymer may contain one or more vinyl acetate units of the following formula (IX):

[0049]

[0050] In some aspects, the vinyl chains of the modified vinyl polymer can comprise any one or more of the following units: units comprising an ester moiety selected from formula (II), (III), (IV), (V), units comprising an ether moiety derived from monomers selected from formula (VI) and (VII), and optionally one or more units selected from formula (VIII) and (IX). In some forms, the vinyl chains of the modified vinyl polymer can comprise any one or more of the following units: units comprising an ester moiety selected from formula (II), (III), (IV), (V), and optionally one or more units selected from formula (VIII) and (IX).

[0051] The modified vinyl polymer can provide a range of possible properties and performance characteristics. In some aspects, the weight average molecular weight (Mw) of the modified vinyl polymer can be from about 15,000 g / mol to about 200,000 g / mol, from about 60,000 g / mol to about 160,000 g / mol, from about 90,000 g / mol to about 125,000 g / mol, or from about 100,000 g / mol to about 115,000 g / mol. In some aspects, the number average molecular weight (Mn) of the modified vinyl polymer can be from about 500 g / mol to about 90,000 g / mol, from about 1000 g / mol to about 80,000 g / mol, from about 2000 g / mol to about 70,000 g / mol, from about 15,000 g / mol to about 60,000 g / mol, from about 30,000 g / mol to about 45,000 g / mol, or from about 35,000 g / mol to about 40,000 g / mol. In some forms, the polydispersity index (Mw / Mn) of the modified vinyl polymer can be from about 2.0 to about 27.0, from about 2.0 to about 8.0, from about 2.0 to about 4.0, from about 2.5 to about 3.5, or from about 2.75 to about 2.95. The foregoing molecular weights and polydispersity can be determined using gel permeation chromatography (GPC).

[0052] Generally, a method for preparing a modified vinyl polymer can include: reacting polyvinyl alcohol having a degree of hydrolysis of at least 50% with one or more of an acid anhydride and an epoxide reactant. In some aspects, the polyvinyl alcohol can be dissolved in a first solvent to prepare a first solution, one or more reactants can be dissolved in a second solvent to prepare a second solution, and the first and second solutions can be combined to effect the reaction. In other aspects, a single solvent can be used to dissolve the polyvinyl alcohol and the reactants can be added to the solution of polyvinyl alcohol to effect the reaction.

[0053] Examples of solvents that can be used in the method for preparing a modified polyvinyl polymer include water, acetonitrile, and mixtures thereof. In some aspects, polyvinyl alcohol is dissolved in water, and one or more of the anhydride reactant and the epoxide reactant are dissolved in acetonitrile, and then the two solutions are combined to carry out the reaction. In other aspects, polyvinyl alcohol is dissolved in water, and then one or more reactants are added to the aqueous solution comprising polyvinyl alcohol to carry out the reaction.

[0054] In the method for preparing a modified polyvinyl polymer, any available mass ratio or molar ratio of one or more reactants to polyvinyl alcohol can be used. In one mode, the mass ratio of one or more of the anhydride reactant and the epoxide reactant to polyvinyl alcohol ranges from 0.01:1 to 0.5:1, in another aspect, the mass ratio is from 0.05:1 to 0.4:1, in another aspect, the mass ratio is from 0.06:1 to 0.3:1, and in yet another mode, the mass ratio is from 0.1:1 to 0.15:1.

[0055] Generally, the method for preparing a modified polyvinyl polymer can be carried out in a batch or continuous manner. The batch process may include: placing all the reactants in a reaction vessel and carrying out the reaction until completion. The continuous process can run for a long time and continuously produce reaction products as reactants are fed to the process and reaction conditions are maintained. In some forms, the method for preparing a modified polyvinyl polymer is carried out in a flow reactor comprising a passageway through which polyvinyl alcohol and one or more reactants flow and react. A solution comprising polyvinyl alcohol can be pumped through the flow reactor at a specific rate and concentration, while an additional solution comprising one or more reactants (such as an anhydride and / or an epoxide) can be pumped through the reactor at a specific rate and concentration. The chemical structure, composition, and properties of the product exiting the flow reactor can be regulated by adjusting the concentration and flow rate of each solution.

[0056] Generally, the method for preparing a modified polyvinyl polymer can be carried out for any available reaction time. In some forms, the method for preparing a modified polyvinyl polymer includes reacting polyvinyl alcohol with one or more reactants at a temperature in the range of about 60 °C to about 90 °C, about 70 °C to about 80 °C, about 75 °C to about 95 °C, about 80 °C to about 90 °C, or about 82 °C to about 88 °C.

[0057] The method of the present invention may further include: inducing crosslinking of the modified polyvinyl polymer. Without wishing to be bound by theory, it is believed that the degree of crosslinking modifies the rigidity and strength of the material, as well as the water solubility of the material.

[0058] In some aspects, the tensile strength and elongation of a polymer film including a modified polyvinyl polymer are sufficient to suitably package an edible product. In one aspect, according to ASTM D882, the tensile strength of a polymer film including the modified polyvinyl polymer is greater than about 50 N. In some forms, the tensile strength of a polymer film including the modified polyvinyl polymer ranges from about 50 N to about 200 N, from about 60 N to about 150 N, or from about 70 N to about 100 N.

[0059] In yet another aspect, the puncture strength of a polymer film including a modified polyvinyl polymer is sufficient to suitably package an object. In one aspect, according to ASTM F1306, the puncture strength of a polymer film including the modified polyvinyl polymer is greater than about 20 N. In some forms, the puncture strength of a polymer film including the modified polyvinyl polymer ranges from about 50 N to about 110 N, from about 70 N to about 100 N, or from about 80 N to about 90 N.

[0060] As described above, the modified polyvinyl polymers provided herein can be used to prepare films, such as films that can be used for wrapping or packaging. Generally, the packaging can enclose or otherwise contain any type of product. In some aspects, the packaging including the modified polyvinyl polymer can contain foods such as: condiments (e.g., ketchup, mayonnaise, mustard, appetizers, yuzu vinegar, oil, vinegar, tartar sauce, Fry sauce, and soy sauce), salad dressings, cheeses, vegetables, soups, or meats. Examples of food packaging include sachets, bags, and thermoformed containers. In other forms, the packaging can be formed by thermally or mechanically sealing one or more films.

[0061] Without wishing to be bound by any particular theory, it is believed that some forms of modified polyvinyl polymers having a relatively high amount derived from the succinic anhydride moiety exhibit a higher level of water resistance when compared to modified polyvinyl polymers having a relatively low amount derived from the succinic anhydride moiety. Without wishing to be bound by any theory, it is believed that a high number of residual hydroxyl groups in the modified polyvinyl polymer that are not modified by the anhydride reactant increases the water solubility of the polymer, while a modified polyvinyl polymer having relatively fewer hydroxyl groups will be less soluble. Thus, it is believed that the solubility of the modified polyvinyl polymer can be adjusted by increasing or decreasing the degree of modification by the anhydride reactant.

[0062] In some forms, the polymer film can generally include one or more modified polyvinyl polymers. In some aspects, the packaging can generally include one or more modified polyvinyl polymers, or one or more polymer films including one or more modified polyvinyl polymers and optionally additional polymers, or a polymer film that does not include a modified polyvinyl polymer. The packaging containing the modified polyvinyl polymer can generally contain products having any combination of properties.

[0063] In some ways, a food bag may include a bag body that includes a film containing a modified polyvinyl polymer. A food product may be enclosed within the bag body. In some aspects, a condiment is enclosed within the bag body.

[0064] The packaging film may include one or more additional layers in order to provide desired properties to the overall packaging film. For example, the one or more additional layers may be included in order to provide desired tensile strength, puncture strength, water vapor permeability, and / or oxygen transmission rate values.

[0065] In one way, the packaging has a structure and components that are compatible with the object being packaged in order to provide a desired shelf life. In various aspects, this compatibility may avoid or reduce premature degradation and mechanical weaknesses of the packaging materials in contact with the object being packaged, prevent or reduce the leaching of materials from the packaging and into contact with the object being packaged, or prevent or reduce the loss of moisture from the packaged materials through the packaging.

[0066] In some aspects, the packaging may include a polymer film that includes one or more modified polyvinyl polymers, wherein one or more of the packaging and the polymers have one or more properties (e.g., chemical composition and mechanical properties) that are tailored for contact with a specific object being packaged.

[0067] The packaging made from a modified polyvinyl polymer may include a single layer film, or in another aspect, may include two or more layer films. Similarly, the modified polyvinyl polymer may be laminated with other materials such that the modified polyvinyl polymer may be an inner layer, an outer layer, and / or an intermediate layer. Further, multilayer modified polyvinyl polymer materials may be used by themselves, or in combination with other layers. Examples of other layers include, but are not limited to: ethyl cellulose, soy protein, and other biopolymers.

[0068] In some aspects, the packaging may enclose or otherwise accommodate products having a moisture content in the range of: about 1 wt% to about 99 wt%, about 5 wt% to about 95 wt%, about 10 wt% to about 90 wt%, about 20 wt% to about 80 wt%, about 30 wt% to about 70 wt%, about 40 wt% to about 60 wt%, or about 45 wt% to about 55 wt%. In some forms, the bag contains a modified polyvinyl polymer and encloses a condiment (such as ketchup) having a moisture content in the range of: about 60 wt% to about 70 wt%, and in another aspect about 63 wt% to about 70 wt%.

[0069] The packaging may contain a modified polyvinyl polymer and enclose a product having any water activity (a w )). In some aspects, the packaging may enclose or otherwise accommodate a wProducts in the range of approximately 0.05 to approximately 0.99, approximately 0.1 to approximately 0.98, approximately 0.2 to approximately 0.9, approximately 0.3 to approximately 0.8, approximately 0.4 to approximately 0.7, or approximately 0.5 to approximately 0.6. In some forms, the bag contains a modified vinyl polymer and encloses a w Ketchup in the range of approximately 0.91 to approximately 0.98, approximately 0.92 to approximately 0.97, approximately 0.93 to approximately 0.96, or approximately 0.94 to approximately 0.95.

[0070] The packaging may contain a modified vinyl polymer and enclose a product with any sugar content (°Bx). In some aspects, the packaging may enclose or otherwise accommodate products with a sugar content in the following ranges: approximately 0.5 °Bx to approximately 95 °Bx, approximately 1 °Bx to approximately 90 °Bx, approximately 5 °Bx to approximately 85 °Bx, approximately 10 °Bx to approximately 80 °Bx, approximately 20 °Bx to approximately 70 °Bx, approximately 30 °Bx to approximately 60 °Bx, or approximately 40 °Bx to approximately 50 °Bx. In some forms, the bag contains a modified vinyl polymer and encloses ketchup with a sugar content in the following ranges: approximately 30 °Bx to approximately 40 °Bx, approximately 31 °Bx to approximately 39 °Bx, approximately 32 °Bx to approximately 38 °Bx, approximately 33 °Bx to approximately 37 °Bx, or approximately 34 °Bx to approximately 36 °Bx.

[0071] The packaging may contain the modified vinyl polymer provided herein and enclose a product with a generally basic, acidic, or neutral pH. In some aspects, the packaging may enclose or otherwise accommodate products with a pH in the following ranges: approximately 3 to approximately 9, approximately 4 to approximately 8, approximately 4.5 to approximately 5, approximately 6 to approximately 7, approximately 3.5 to approximately 7.5, approximately 4 to approximately 7, approximately 4.5 to approximately 6.5, or approximately 5 to approximately 6. In some forms, the bag contains a modified vinyl polymer and encloses ketchup with a pH range of approximately 3 to approximately 4.5, approximately 3 to approximately 4, approximately 3.1 to approximately 3.9, approximately 3.8 to approximately 3.99, or a pH less than approximately 4.

[0072] In one specific embodiment, ketchup with a pH range of approximately 3.2 to approximately 4.0 is enclosed in a bag.

[0073] In one embodiment, the hydrophilic layer can be used as the inner layer of a food packaging film, while the outer layer can have a different composition that allows for faster degradation upon contact with water and / or soil.

[0074] Coatings can also be used to modify the properties and functions of the modified vinyl polymer material, especially when used as packaging for edibles. Such coatings include, but are not limited to: waxes such as beeswax, and other biopolymers.

[0075] In one embodiment, the package includes a first film and a second film, the first film comprising a modified polyvinyl polymer having properties suitable for food contact, and the second film comprising an unmodified polyvinyl alcohol polymer that is readily soluble upon contact with moisture. Examples of unmodified polyvinyl alcohol polymers include those described herein that have any degree of hydrolysis but whose hydroxyl and acetate moieties are not further capped or modified. In some forms, the multi-layer package includes an inner film and an outer film, the inner film comprising the modified polyvinyl polymer that is in direct contact with the product being packaged, and the outer film comprising the unmodified polyvinyl alcohol polymer that is not directly exposed to the product. In other forms, the multi-layer package includes an inner film and an outer film, the inner film comprising the unmodified polyvinyl alcohol that is in direct contact with the product being packaged, and the outer film comprising the modified polyvinyl polymer that is not directly exposed to the product.

[0076] Figure 3A An embodiment of a food bag is shown, the food bag comprising a bag body 2 having seals 4 on three sides. The bag is formed by folding and sealing three sides of a film. Figure 3B Shows Figure 3A A cross-section of the food bag taken along A-A in Figure 3B In, the first film 6 comprises a modified polyvinyl polymer and is in contact with an edible object 8 (such as ketchup) disposed within the bag body. The second film 10 comprises an unmodified polyvinyl alcohol polymer and forms the exterior of the bag body. Although the bag shown has seals on three sides, it should be understood that other numbers of seals may be used, such as two seals, four seals, and so on.

[0077] Figure 3C Shows an enlarged cross-section of the food bag embodiment shown in Figure 3B taken in frame B.

[0078] Each example was prepared and tested in order to compare the effects of starting materials, manufacturing methods, and other variables related to the materials.

[0079] Examples

[0080] The following examples are provided to illustrate the various embodiments without any limiting effect.

[0081] Example 1 - A modified polyvinyl polymer comprising units produced by the reaction between succinic anhydride and the hydroxyl groups of polyvinyl alcohol

[0082] The polyvinyl alcohol solution was prepared as follows: 1.0 g of granular PVOH-418 (polyvinyl alcohol soluble in warm water, degree of hydrolysis 92%, from Aquapak Polymers Ltd., Birmingham, UK) was dissolved in 10 mL of water. The anhydride solution was prepared by dissolving 0.5 g of succinic anhydride (sold by Merck / Sigma Aldrich) in 5 mL of acetonitrile.

[0083] Using a flow reactor assembly including a peristaltic pump, the polyvinyl alcohol solution and the anhydride solution were delivered to a T-mixer. The T-mixer mixed the solutions into a homogeneous reaction mixture in a turbulent manner, and the reaction mixture was then fed into a reactor. The reactor included two reactor cores constructed from PFA (perfluoroalkoxy alkane) pipe coils. A reactor control unit controlled the temperature and residence time of the reaction mixture within the reactor cores. The total reaction time (residence time) of the reaction mixture through the two reactor cores was 10 - 30 minutes, and the temperature was 60–70 °C. Throughout the residence time, the reaction mixture remained homogeneous and did not scale or block the reactor pipes. A product collection bottle collected the polymeric material leaving the flow reactor assembly. The collected product was poured into a petri dish and dried by slow evaporation at 40 °C for 1 to 2 days. The resulting film can be used in packaging materials.

[0084] Example 2 - A modified polyvinyl polymer comprising units generated by the reaction between propylene oxide and the hydroxyl groups of polyvinyl alcohol ("POxide" film)

[0085] The polyvinyl alcohol solution was prepared as follows: 1.0 g of PVOH-418 (polyvinyl alcohol soluble in warm water, degree of hydrolysis 92%, from Aquapak Polymers Ltd., Birmingham, UK) was dissolved in 10 mL of water. The epoxide solution was prepared by mixing 0.5 mL of propylene oxide with 5 mL of acetonitrile. The polyvinyl alcohol solution and the epoxide solution were fed to the reactor assembly described in Example 1 and subjected to the same reaction conditions and drying procedure used in Example 1.

[0086] Figure 4 Two petri dishes are shown. The left dish contains the product of Example 2, which has a gelatinous, clear, and colorless appearance. The right dish contains the product of Example 1, which has an opaque and rubbery appearance. Both modified polymers provide flexible films and are completely water-soluble at 40 °C. The resulting films can be used in packaging materials.

[0087] IR testing

[0088] Infrared spectroscopy (IR) was used to evaluate the differences in vibration frequencies associated with the acetate moieties in two modified polyvinyl polymers of Examples 1 and 2 and unmodified polyvinyl alcohol (PVOH-418). The IR spectrum also evaluated the appearance of vibrations associated with the units resulting from the reaction of succinic anhydride in Example 1 and the units resulting from the reaction of propylene oxide in Example 2. The IR spectrum was obtained using a Bruker Platinum spectrometer (neat, ATR sampling).

[0089] Figure 5 is the IR spectrum of unmodified PVOH-418, Figure 6 is the IR spectrum of Example 1, while Figure 7 is the IR spectrum of Example 2. When compared with the band at 1714 cm Figure 5 in -1 , the spectrum in Figure 6 shows a strong band at 1691 cm -1 associated with the structure modified by succinic anhydride. When compared with Figure 5 , the spectrum in Figure 7 shows an additional broad band at 1644 cm -1 associated with the modification by propylene oxide.

[0090] Example 3 - A modified polyvinyl polymer comprising units resulting from the reaction between succinic anhydride and the hydroxyl groups of polyvinyl alcohol

[0091] Suc1 Film

[0092] The polyvinyl alcohol solution was prepared as follows: 30 g of PVOH-418 was dissolved / suspended in 300 mL of deionized water. The solution was placed in a 500 mL Schott glass bottle containing a 2 cm magnetic stir bar, which was placed on an IKA hot plate with magnetic stirring. Subsequently, 4 g of solid succinic anhydride was added to the polyvinyl alcohol solution, and the mixture was vigorously stirred at 80 °C for 5 hours. The reaction mixture was initially turbid but became a clear solution within 1 hour.

[0093] Without prior cooling, the modified polyvinyl polymer was poured into four 40 x 20 cm plastic storage boxes, aiming for approximately 70 g of product / box. After drying and evaporating for two days in a fume hood in the absence of light, the film was peeled off the box and stored between sheets of paper to avoid bending.

[0094] Suc2 film

[0095] The same procedure as in Example "Suc1" above was carried out, except that 2 g (instead of 4 g) of solid succinic anhydride was added to the polyvinyl alcohol solution. A sample film was obtained.

[0096] Suc3 film

[0097] The same procedure as in the above Example "Suc1" was carried out, except that 6 g of solid succinic anhydride was added to the polyvinyl alcohol solution. A sample film was obtained.

[0098] POxide film

[0099] The same procedure as in Example 2 above was carried out using propylene oxide. A sample film was obtained. Limited tests were carried out on this propylene oxide ("POxide") film.

[0100] The films of the dried Suc1, Suc2, Suc3, and POxide samples were peeled from the casting box. At the time of peeling, these films were generally completely transparent, but developed a slightly opaque appearance within a few days, which may indicate further drying. After peeling, the films continued to dry without any sticky quality.

[0101] The samples Suc1, Suc2, Suc3, and POxide were compared with the following: conventional polyvinyl alcohol samples: PVOH soluble in hot water ("HWS PVOH"; sold by Aquapak as 30164P); and PVOH soluble in warm water ("WWS PVOH"; sold by Aquapak as 33104P). The average gauge lengths of the films of Examples Suc1, Suc2, Suc3, POxide, HWS PVOH, and WWSPVOH are shown in Table 1.

[0102] Table 1

[0103] Sample Average gauge length of film (μm) Suc1 141 Suc2 42 Suc3 95 POxide 52 HWS PVOH (comparison) 25 WWS PVOH (comparison) 25

[0104] Tests

[0105] IR Test

[0106] The vibration frequencies generated by Suc1 were evaluated using infrared spectroscopy (IR). Figure 8 The IR spectrum of Suc1 is provided in. Figure 5 The comparison of the IR spectrum of unmodified PVOH-418 in with Figure 8 the Suc1 spectrum in revealed a distinct change in the carbonyl stretching region in the range of 1600 - 1800 cm -1 which is consistent with the moiety introduced by reaction with succinic anhydride. More specifically, a shift from approximately 1714 cm of PVOH-418 to approximately 1703 cm of Suc1 was observed. -1 to -1 The IR spectra were obtained using a Bruker Platinum spectrometer (pure, ATR sampling).

[0107] Subsequently, the disintegration, cold dispersibility / solubility, and hot dispersibility / solubility of the test samples were tested under composting conditions. The “Suc1” sample had a thickness of approximately 35 microns, the “Suc3” sample had a thickness of approximately 76 microns, the Aquapak HWS sample had a thickness of approximately 35 microns, and the Aquapak WWS sample had a thickness of approximately 29 microns.

[0108] Cold water dispersibility and solubility

[0109] The cold water dispersibility test was conducted as follows: In a 2 L beaker, at 150 rpm under stirring conditions (magnetic stir bar), at least 1 g (based on dry weight) of Suc1, HWS PVOH, and WWS PVOH membranes (with dimensions of at least 25 mm x 25 mm) were mixed with 1 L of tap water. The membranes were stirred for 16 hours at 25 °C ± 2 °C in the dark. After this time period, the water dispersibility fraction (D) of the membranes was determined by sieving through a 10 mm sieve.

[0110] The test was conducted according to the following: EN 14987 Plastics – Evaluation of disposability in waste water treatment plants – Test scheme for final acceptance and specifications (2006). The test was repeated three times.

[0111] Table 2 shows the determination results of the cold water dispersibility (D) of the samples. For the purposes of this article, at least 90% of the raw material should pass through a 10 mm sieve to be considered cold water dispersible. For solubility, >90% of the material should pass through a 0.45 μm filter. Table 2 also shows the pH at the start and end (16 hours) of the test. According to EN 14987 (2006), the initial pH should be neutral. The POxide sample was not tested.

[0112] Table 2

[0113]

[0114] SD = Standard Deviation

[0115] At the end of the cold water dispersibility test (after 16 hours), a clear solution was obtained for Suc1. After stirring for 16 hours (end of the test), no significant pH change was observed for Suc1. No object debris was retained on the 10 mm sieve, and the reactor contents were directly filtered through a 0.45 μm filter. The filtration through the 0.45 μm filter was extremely slow, and only a few droplets passed through the filter after approximately 3 hours. It was determined that the sample of Suc1 was cold water dispersible but not cold water soluble.

[0116] The solubility of HWS PVOH was not evaluated because the resulting dispersibility was insufficient. The reactor contents of the test material WWS PVOH were filtered through a 0.45 μm filter. The filtration was extremely slow, and only a few droplets passed through the filter after several hours. Thus, filtration was not possible, and the test material could not be defined as cold water soluble. From the results of this test, it can be summarized that HWS PVOH could neither be dispersed in cold water nor was it cold water soluble. The test material WWS PVOH was cold water dispersible but not cold water soluble. For both the HWS PVOH and WWS PVOH materials, the pH increased slightly after 16 hours.

[0117] Hot water dispersibility and solubility

[0118] The hot water dispersibility test was conducted as follows: In a 2 L beaker, with stirring at 150 rpm, at least 1 g (based on dry weight) of the membrane (dimension at least 25 mm x 25 mm) was mixed with 1 L of tap water. The membrane was stirred at 60 °C ± 2 °C for 16 hours in the dark. After this time period, the water dispersibility fraction (D) of the suspension was determined by sieving through a 10 mm sieve. The entire test was 16 hours, and the test was repeated three times.

[0119] According to EN 14987 (2006), if a material obtains a dispersibility fraction of ≥ 90% after dissolution in hot water, the material is considered to be dispersible in hot water. Further, according to EN 14987 (2006), the initial pH should be neutral. Table 3 shows the results of the hot water dispersibility test. Table 3 shows the amount of the test material added to 1 L of tap water at the start and the amount of the material remaining on the 10 mm sieve after stirring at 150 rpm for 16 hours at 60 °C after drying at 50 °C.

[0120] Table 3

[0121]

[0122] SD = Standard Deviation

[0123] Hot water solubility was determined by filtration through a 0.45 μm filter. If it is soluble in hot water, after filtration through a 0.45 μm filter, a soluble fraction of ≥ 90% must be obtained.

[0124] The film of Suc1 showed dispersibility and solubility at 60 °C. At the end of the hot water dispersibility test (after 16 h), Suc1 gave a clear solution. At the end of the test (16 h), the pH in the reactor of Suc1 was measured to have decreased slightly, where the pH decreased from 8.6 to 8.2 - 8.3. No object debris was retained on the 10 mm sieve, so the reactor contents were directly filtered through a 0.45 μm filter. The filtration was very rapid, so the solubility could be determined. Only 0.3% of the original weight was retained on the 0.45 μm filter, corresponding to a solubility of 99.7 ± 0.1%. Suc1 meets the dispersibility and solubility criteria specified in EN 14987 (2006) and can be defined as dispersible in hot water and soluble in hot water.

[0125] After 16 h, Suc3 gave a clear solution. No object debris remained on the 10 mm sieve. Since no object debris was retrieved from the sieve of sample Suc3, the dispersibility was calculated to be 100%. The reactor contents were filtered through a 0.45 micron filter. The filtration progressed slowly. After more than 1 h, only a few droplets passed through the filter. Thus, the Suc3 film cannot be defined as soluble in hot water. Therefore, the Suc3 film is characterized as dispersible in hot water rather than soluble in hot water. The pH decreased significantly from 8.0–8.1 to a value between 6.0 and 7.0.

[0126] The object debris of the tested HWS PVOH was curled but still mostly intact and remained on the 10 mm sieve. The solubility of HWS PVOH was not evaluated because the obtained dispersibility was insufficient. The results in the above table show that 73.1% of the original weight of HWS PVOH remained on the 10 mm sieve, corresponding to a dispersibility of 26.9% ± 2.0%. The pH remained relatively stable during the 16 h period.

[0127] For WWS PVOH, since no object debris was removed from the sieve, the dispersibility was calculated to be 100%. The reactor contents of WWSPVOH were filtered on a 0.45 μm. The filtration proceeded extremely slowly and after several hours only a few droplets passed through the filter. Thus, it could not be filtered and the test material could not be defined as soluble in hot water. The pH remained relatively stable during the 16 h period.

[0128] From the results of this test, HWS PVOH is neither dispersible in hot water nor soluble in hot water. The test material WWS PVOH is dispersible in hot water but not soluble in hot water.

[0129] Additional solubility tests

[0130] The solubility of the film samples of Examples Suc1, Suc2, Suc3, and POxide was tested in warm water (40 °C). Fragments of the film were added to water at 40 °C. The results are shown in Table 4.

[0131] Table 4

[0132]

[0133] The films (Suc2 and Suc3) containing the minimum and maximum amounts of the units resulting from the reaction between succinic anhydride and the hydroxyl groups of polyvinyl alcohol showed faster dissolution compared to the film (Suc1) containing an intermediate amount of this unit.

[0134] All examples of the present invention showed rapid solubility, indicating that the chemical modification of the PVOH polymer did not result in a loss of water solubility.

[0135] Disintegration under composting conditions

[0136] The soil-based disintegration of the films was tested by placing them in compost. During home composting, the high temperatures (>50 °C) obtained during industrial composting processes are generally not reached. Therefore, for a material to be considered home-compostable, it should show sufficient disintegration at ambient temperature. The test setup was based on the international standard ISO 20200 Plastics – Determination of the degree of disintegration of plastic materials under simulated composting conditions in a laboratory-scale test (2015), with some modifications.

[0137] The disintegration of the samples was quantitatively evaluated. The test lasted for 16 weeks. The test materials were placed in a slide frame, mixed with compost, and incubated at 28 °C ± 2 °C in the dark. Each test object was tested twice. The compost consisted of <10 mm mature compost and an 80 / 20 mixture of freshly ground vegetable, garden, and fruit waste (VGF), respectively. If necessary, the compost was stirred and moistened regularly. At the same time, the visual appearance of the slide frame and the test materials was evaluated.

[0138] The mature compost is a mixture of mature VGF and green compost. The VGF compost is derived from the organic fraction of municipal solid waste and is further stabilized and aerated in a pilot-scale composting silo under controlled conditions in the laboratory to obtain fully mature compost. The aging time of the VGF compost is 16 weeks. The green compost is derived from garden waste, prunings, tree roots and stumps and is stabilized in a full-scale composting station. The composts are mixed at a ratio of 50% VGF compost and 50% green compost. The mixture in the compost reactor is manually turned over regularly, during which the disintegration of the test samples is monitored visually.

[0139] The compost disintegration of membrane Suc1 (with a thickness of about 35 μm, measured by a digital micrometer) was evaluated. After 2 weeks, small holes began to appear in the test materials in some of the slide frames. It was noted that the test materials were very sticky. In the following weeks, no significant disintegration progress was observed. After 12 weeks of composting, small holes were noted in the test materials in some of the slide frames, while the test materials in most of the slide frames remained intact. The disintegration progressed slowly, and after 16 weeks of composting at ambient temperature, small holes were present in the test materials in most of the slide frames. However, the test materials in a small number of slide frames remained completely intact. Based on the determination results of the remaining surface of the test materials in the slide frames, it was summarized that the test materials were characterized by an average disintegration percentage of <81%.

[0140] The compost disintegration results of membrane Suc3 (with a thickness of about 76 μm) were also evaluated. After 1 week of composting, the test materials became brown and elastic. In the following weeks, no signs of disintegration were observed. After 20 weeks, the test materials in all of the slide frames still remained completely intact. After 2 weeks, small holes began to appear in the test materials in a few of the slide frames. After 26 weeks of composting, small holes were present in the test materials in some of the slide frames, while the test materials in most of the slide frames remained completely intact. No further progress was observed in the following weeks. After 32 weeks (at the end of the test), small holes were observed in the test materials in a few of the slide frames. However, the test materials in most of the slide frames still remained completely intact. Based on the determination results of the remaining surface of the test materials in the slide frames, it could be summarized that the test material Suc3 was characterized by a disintegration percentage of 0% after 32 weeks of composting at ambient temperature.

[0141] In contrast, two types of unmodified PVOH (Aquapak 30164P (soluble in hot water; 35 microns) and Aquapak 33104P (soluble in warm water; 29 microns)) remained completely intact (0% disintegration) at 16 weeks. For the HWS film samples (approximately 35 microns thick) and WWS film samples (approximately 29 microns thick), there were no signs of disintegration during the test. After 26 weeks, in all slide frames, the test materials remained completely intact. The test materials were characterized by a disintegration percentage of 0% after 26 weeks of composting at ambient temperature.

[0142] The overall results of disintegration, cold dispersibility / solubility, and heat dispersibility / solubility are summarized in Table 5 below:

[0143] Table 5

[0144]

[0145] OTR and WVTR tests

[0146] The oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) of the films of Examples Suc1, Suc2, Suc3, and POxide were tested. According to the tests based on ASTM D3985 and ASTM F1927, the oxygen transmission rate was measured at 23 °C and 0% relative humidity. The target oxygen permeability of the material was <10 cc / m 2 / day. Using the test based on ASTM F1249, the water vapor transmission rate was measured at 38 °C and 90% relative humidity. The target water vapor permeability of the material was less than 13.8 cc / m 2 / day at one week, or less than 6.57 cc / m 2 / day at two weeks.

[0147] Table 6 shows the OTR and WVTR exhibited by the films of Examples Suc1, Suc2, Suc3, and POxide, in contrast to the individual conventional PVOH (control). The OTR results show the average performance of the 4 variables. For use in bags containing tomato ketchup, when used as the only layer of the packaging film, the WVTR and OTR values of the Suc1, Suc2, Suc3, and POxide samples were insufficient. The average gauge length of the tested samples was: Suc1 sample, 141 microns, Suc2 sample, 42 microns, Suc3 sample, 95 microns, and POxide sample, 52 microns.

[0148] Table 6

[0149] Sample <![CDATA[OTR(cc / m 2 / day)]]> <![CDATA[WVTR (cc / m 2 / day)]]> Suc1 22.2 433.1 Suc2 21.7 525.4 Suc3 29.9 696.6 POxide 18.0 875.8 PVOH (comparison) <0.008 >100

[0150] The tensile strength, elongation at break, and puncture strength of the films of Examples Suc1, Suc2, Suc3, and POxide were tested and compared with unmodified PVOH. The target tensile strength and elongation at break were at least 50 N, while the target puncture strength was at least 20 N. Table 7 shows the tensile strength, elongation at break, and puncture strength exhibited by the films of Examples Suc1, Suc2, Suc3, and POxide. In the examples, the tensile strength and puncture tolerance were considered satisfactory, while the elasticity ranged from poor to good.

[0151] Table 7

[0152]

[0153] The films of Examples Suc1, Suc2, Suc3, and POxide were used to form sealed bags for enclosing ketchup. The bag formed from Suc1 ruptured when filled with ketchup. The bag formed from Suc2 could not be filled with ketchup because the films stuck together. The bag formed from Suc3 exhibited a high percentage of ketchup loss and shrank 2 hours after filling. The bag formed from POxide shrank and expelled all the moisture from the ketchup. Thus, each of the Suc1, Suc2, Suc3, and POxide samples, on its own, was not suitable for use in a single-layer bag, but could be combined with other polymer films or coatings to provide bags that can be used to contain food products.

[0154] Example 4 - A modified polyvinyl polymer comprising units produced by the reaction between succinic anhydride and the hydroxyl groups of polyvinyl alcohol

[0155] WWS - Suc

[0156] A polyvinyl alcohol solution was prepared by dissolving / suspending 30 g of PVOH-418 in 300 mL of deionized water. The solution was placed in a 500 mL Schott glass bottle containing a 2 cm magnetic stir bar, which was placed on an IKA hot plate with magnetic stirring. Subsequently, 4 g of solid succinic anhydride was added to the polyvinyl alcohol solution, and the mixture was vigorously stirred at 80 °C for 5 hours. The molecular weights of two samples of the WWS-Suc polymer were tested using GPC with the following settings:

[0157] Instrument Viscotek GPC Max

[0158] Column 2 * 30 cm Agilent OH60 GPC column

[0159] Eluent water + 0.2 m sodium nitrate

[0160] Flow rate 1.0 ml / min

[0161] Detection RI

[0162] Temperature 40 °C

[0163] The sample was injected using an automatic sample injector. Data capture and subsequent data analysis were performed using Viscotek's 'Omnisec' software.

[0164] HWS - Suc

[0165] The polyvinyl alcohol solution was prepared as follows: 30 g of PVOH-E103 (polyvinyl alcohol soluble in hot water, from Aquapak Polymers Ltd., Birmingham, UK) was dissolved / suspended in 300 mL of deionized water. The solution was placed in a 500 mL Schott glass bottle containing a 2 cm magnetic stir bar, which was placed on an IKA hot plate with magnetic stirring. Subsequently, 4 g of solid succinic anhydride was added to the polyvinyl alcohol solution, and the mixture was vigorously stirred at 80 °C for 5 hours. The molecular weight of the HWS-Suc polymer sample was tested using the same equipment and procedure as used for testing the two WWS-Suc samples.

[0166] Table 8 shows the molecular weight moments of the injected samples of the two WWS-Suc samples and the HWS-Suc sample.

[0167] Table 8

[0168] Sample Mw Mn Mw / Mn <![CDATA[M z > WWS - Suc 29,000 1,100 26.2 62,000 WWS - Suc 30,000 1,200 24.7 62,000 HWS - Suc 18,000 2,300 7.9 34,000

[0169] The matters set forth in the foregoing specification and drawings are provided by way of illustration only and not as limitations. Although specific embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the broader aspects of the applicant's contribution. When viewed from an appropriate perspective based on the prior art, it is intended that the actual scope of protection sought be defined in the following claims.

Claims

1. A polymer film, comprising a modified polyvinyl polymer, which comprises polyvinyl chains, and the polyvinyl chains comprise one or more units containing an ester moiety, which are produced by the reaction of an acid anhydride reactant with the hydroxyl groups of polyvinyl alcohol.

2. The polymer film according to claim 1, wherein the acid anhydride reactant comprises one or more of the following: succinic anhydride, acetic anhydride, propionic anhydride, adipic anhydride, glutaric anhydride, pimelic anhydride, suberic anhydride, and malonic anhydride.

3. The polymer film according to claim 1 or 2, wherein the one or more units containing an ester moiety comprise a structure according to formula (II): wherein X represents a divalent group.

4. The polymer film according to claim 3, wherein the divalent group has 2 to 6 carbon atoms.

5. The polymer film according to any one of claims 1 to 4, wherein the one or more units containing an ester moiety comprise a structure according to formula (III):

6. The polymer film according to any one of claims 1 to 5, wherein the polyvinyl chains of the modified polymer comprise one or more crosslinked units having a structure according to formula (IV): wherein X is a divalent group, the polyvinyl chains of the modified polyvinyl polymer comprise the unit (A) represented by parentheses, and for the crosslinked units in the one or more crosslinked units, one of the following conditions is satisfied: the polyvinyl chains of the modified polyvinyl polymer comprise the unit (B) represented by parentheses, or the polyvinyl chains of a separate polymer comprise the unit (B), and the polyvinyl chains of the separate polymer are derived from polyvinyl alcohol.

7. The polymer film according to claim 6, wherein the divalent group X has 2 to 6 carbon atoms.

8. The polymer film according to any one of claims 1 to 7, wherein the polyvinyl chains of the modified polymer comprise one or more crosslinked units having a structure according to formula (V): wherein the polyvinyl chains of the modified polyvinyl polymer comprise the unit (A) represented by parentheses, and for the crosslinked units in the one or more crosslinked units, one of the following conditions is satisfied: the polyvinyl chains of the modified polyvinyl polymer comprise the unit (B) represented by parentheses, or the polyvinyl chains of a separate polymer comprise the unit (B), and the polyvinyl chains of the separate polymer are derived from polyvinyl alcohol.

9. The polymer film according to any one of claims 1 to 8, wherein the polyvinyl chains further comprise one or more vinyl alcohol units having a structure according to formula (VIII):

10. The polymer film according to any one of claims 1 to 8, wherein the polyvinyl chains further comprise one or more vinyl acetate units having a structure according to formula (IX):

11. The polymer film according to any one of claims 1 to 8, wherein the polyvinyl chains further comprise one or more vinyl alcohol units having a structure according to formula (VIII): and one or more vinyl acetate units having a structure according to formula (IX):

12. The polymer film according to any one of claims 1 to 9, wherein the polyvinyl chains are derived from a polyvinyl alcohol polymer having a degree of hydrolysis of 80% to 100%.

13. The polymer film according to any one of claims 1 to 9, wherein the polyvinyl chain is derived from a polyvinyl alcohol polymer having a degree of hydrolysis of 90% to 100%.

14. The polymer film according to any one of claims 1 to 9, wherein the polyvinyl chain is derived from a polyvinyl alcohol polymer having a degree of hydrolysis of 92% to 100%.

15. The polymer film according to any one of claims 12 to 14, wherein the polyvinyl chain has the following structure, wherein about 50 to about 100% of the hydroxyl groups of the polyvinyl alcohol polymer have reacted with an acid anhydride reactant to form the unit including an ester moiety.

16. A food bag, comprising: a bag body, the bag body including the polymer film according to any one of claims 1 to 15, and a second film, and a food product, which is enclosed in the bag body.

17. The food bag according to claim 16, wherein the food product has an acidic pH.

18. The food bag according to claim 15 or 16, wherein the sugar content of the food product ranges from about 15 °Bx to about 50 °Bx.

19. The food bag according to claims 16 to 18, wherein the water activity of the food product ranges from about 0.90 to about 0.

99.

20. The food bag according to any one of claims 16 to 19, wherein the water content of the food product ranges from about 50% by weight to about 95% by weight.

21. The food bag according to any one of claims 16 to 20, wherein the food product contains a condiment.

22. The food bag according to claim 21, wherein the condiment is: ketchup, mayonnaise, mustard, appetizer, yuzu vinegar, oil, vinegar, tartar sauce, Fry sauce, or soy sauce.

23. The food bag according to claim 21, wherein the condiment contains ketchup having a pH range of 3.8 to 4.

0.

24. The food bag according to any one of claims 16 to 23, wherein the second film includes an unmodified polyvinyl alcohol polymer, the polymer film contacts the food product enclosed in the bag body, and the second film forms at least a part of the exterior of the bag body.

25. A polymer film, comprising a modified polyvinyl polymer, which includes a polyvinyl chain containing one or more of the following: a unit including an ester moiety, which is produced by the reaction of an acid anhydride reactant with a hydroxyl group of polyvinyl alcohol, and a unit including an ether moiety, which is produced by the reaction of an epoxide reactant with a hydroxyl group of polyvinyl alcohol, the epoxide reactant having the structure according to formula (VI): wherein R represents a monovalent group including 0 to 5 carbon atoms.

26. The polymer film according to claim 25, wherein the unit including an ether moiety is produced by the reaction of propylene oxide with a hydroxyl group of polyvinyl alcohol.

27. A method for manufacturing a modified polyvinyl polymer, the method comprising: reacting polyvinyl alcohol with an acid anhydride reactant in the presence of a solvent.

28. The method according to claim 27, wherein the acid anhydride reactant includes one or more of the following: succinic anhydride, acetic anhydride, propionic anhydride, adipic anhydride, glutaric anhydride, pimelic anhydride, suberic anhydride, and malonic anhydride.

29. The method according to claim 27 or 28, wherein the solvent comprises water.

30. The method according to any one of claims 27 to 29, wherein the mass ratio of the anhydride reactant to the polyvinyl alcohol ranges from 0.01:1 to 0.5:

1.

31. The method according to any one of claims 27 to 30, the method producing a modified polyvinyl polymer, the modified polyvinyl polymer comprising a polyvinyl chain comprising one or more units comprising a structure according to formula (II): wherein X represents a divalent group.

32. The method according to claim 31, wherein the divalent group has 2 to 6 carbon atoms.

33. The method according to claim 31 or claim 32, wherein the one or more units comprise a structure according to formula (III):

34. The method according to any one of claims 31 to 33, the polyvinyl chain further comprising one or more vinyl alcohol units having a structure according to formula (VIII):

35. The method according to any one of claims 31 to 33, the polyvinyl chain further comprising one or more vinyl acetate units having a structure according to the following formula (IX):

36. The method according to any one of claims 31 to 33, the polyvinyl chain further comprising one or more vinyl alcohol units having a structure according to formula (VIII): and one or more vinyl acetate units having a structure according to formula (IX):

37. The method according to any one of claims 27 to 36, the reaction of the polyvinyl alcohol with the anhydride reactant being carried out in a batch process.

38. The method according to any one of claims 27 to 36, the reaction of the polyvinyl alcohol with the anhydride reactant being carried out in a continuous process.

39. The method according to claim 38, the continuous process comprising: feeding the polyvinyl alcohol and the anhydride reactant to a flow reactor.

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