Modified polyvinyl polymers and food packaging materials containing the polymers

Abstract

A polymeric material is provided that includes a modified polyvinyl polymer having a polyvinyl chain including one or more units having a moiety formed by the reaction of a reactant with polyvinyl alcohol. A method for producing the modified polyvinyl polymer includes reacting polyvinyl alcohol with one or more reactants in the presence of a solvent. A packaging material includes the polymeric material that includes the modified polyvinyl polymer.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 422,801, filed November 4, 2022, which is incorporated herein by reference in its entirety.

[0002] This application relates to polymeric materials, including packaging for food products, and methods of manufacture. [Background technology]

[0003] Packaging materials are used to contain and protect various items during storage and transportation. Traditionally, various materials, including cardboard, plastic, metal, and glass, have been used for packaging. However, many packaging materials are disposed of in landfills after use. Nonrenewable resources, such as petroleum, have been used to manufacture traditional plastics. While plastic-based packaging may be desirable due to its low cost, packaging materials containing such plastics can persist in the environment for a considerable period after disposal. Some polymeric films, such as polyvinyl alcohol (PVOH), are water-soluble. However, it is believed that PVOH or its derivatives may persist in the environment even after dissolving in water. Summary of the Invention

[0004] Additionally, some polymeric materials may not provide sufficient mechanical properties, such as tensile strength, puncture resistance, water vapor permeability, and oxygen permeability, required for certain applications. For example, while water solubility may be beneficial for some applications, solubility may limit the usefulness of the material as a packaging material for liquid foods or foods with high water activity. Additionally, the pH of the liquid or food may be detrimental to the stability of the packaging material over the desired shelf life of the product. [Brief explanation of the drawings]

[0005] [Figure 1]FIG. 1 shows an embodiment of a reaction scheme for preparing a modified polyvinyl polymer (modified polyvinyl polymer). [Figure 2] FIG. 2 shows an embodiment of a reaction scheme for preparing a modified polyvinyl polymer via the reaction of polyvinyl alcohol with succinic anhydride. [Figure 3] Figures 3A, 3B and 3C show various views of an example sachet. [Figure 4] FIG. 4 shows an example film. [Figure 5] FIG. 5 provides the IR spectrum of an exemplary polymeric material. [Figure 6] FIG. 6 provides the IR spectrum of an exemplary polymer material. [Figure 7] FIG. 7 provides the IR spectrum of an exemplary polymer material. [Figure 8] FIG. 8 provides the IR spectrum of an exemplary polymer material. DETAILED DESCRIPTION OF THE INVENTION

[0006] Elements in the figures are illustrated for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions and / or relative positioning of some elements in the figures may be exaggerated relative to other elements to help improve understanding of various embodiments of the present invention. Also, to facilitate understanding of various embodiments of the present invention, common but well-understood elements that are useful or necessary in commercially feasible embodiments are often not shown. Certain actions and / or steps may be described or depicted in a particular order of occurrence, although those skilled in the art will understand that such specificity regarding order is not actually required. The terms and phrases used herein have the ordinary technical meanings ascribed to such terms and phrases by those skilled in the art as set forth above, unless a different specific meaning is otherwise defined herein.

[0007] Provided herein are modified polyvinyl polymers (modified polyvinyl polymers) that can be used to prepare packaging materials. The modified polyvinyl polymers can include structures derived from one or more biobased components. The modified polyvinyl polymer materials can be formed to have a variety of properties and functional capabilities for different applications. In certain approaches, polymer films can be made from or include one or more modified polyvinyl polymers and can be used to produce food packaging films containing aqueous foods such as condiments. In certain embodiments, the food packaging is in the form of a pouch or sachet. Methods for producing the modified polyvinyl polymers, as well as various materials containing the modified polyvinyl polymers, are also provided.

[0008] 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 forms that can be used to form polymeric films, such as in industrial processing and packaging systems. Packaging materials can contain one or more modified polyvinyl polymers and have specifically tailored material properties.

[0009] Modified polyvinyl polymers can be produced by modifying polyvinyl polymers, such as polyvinyl alcohol, to create new moieties on the polyvinyl chain. In some embodiments, the modified polyvinyl polymer comprises a polyvinyl chain containing one or more units containing an ester moiety formed by the reaction of an anhydride reactant with the hydroxyl moiety of polyvinyl alcohol. In other embodiments, the modified polyvinyl polymer comprises a polyvinyl chain containing one or more units containing an ether moiety formed by the reaction of an epoxide reactant with the hydroxyl moiety of polyvinyl alcohol.

[0010] In one approach, a method for forming a modified polyvinyl polymer can include reacting polyvinyl alcohol with one or more reactants to produce a modified polyvinyl polymer containing moieties not present in the unmodified polyvinyl alcohol. Such methods can be carried out as a batch or continuous process.

[0011] In some embodiments, the packaging film can include a polymeric material containing structures derived from one or more biobased components. In some embodiments, the packaging material optionally includes conventional polymers such as polyethylene, polyethene terephthalate, and polypropylene. The packaging material can include one or more modified polyvinyl polymers. The modified polyvinyl polymer can include one or more structures derived from one or more biobased components. The polymer resin used to manufacture the packaging film can include one or more modified polyvinyl polymers and, optionally, one or more polymers other than the modified polyvinyl polymers. The polymer resin can generally take any form, such as pellets, granules, films, sheets, flexible packages, or containers. For example, sheets or films can be formed by extrusion, wet casting, or meltblowing. In some embodiments, the film or sheet can be formed from pellets.

[0012] Modified polyvinyl polymers generally can include polyvinyl chains derived from any polyvinyl polymer, which can be produced by one or more types of vinyl monomers. For example, polyvinyl alcohol can be produced by polymerizing vinyl acetate monomers to form polyvinyl acetate. Polyvinyl alcohol can then be formed by hydrolyzing the acetate moieties of polyvinyl acetate to hydroxyl moieties. When polyvinyl alcohol is formed by incomplete hydrolysis, it can retain a certain percentage of acetate moieties. For example, various polyvinyl alcohols can have a degree of hydrolysis of 50% or more, 60% or more, 70% or more, 75% or more, 80% or more, 85% or more, 90% or more, 91% or more, 92% or more, 93% or more, 94% or more, 95% or more, 96% or more, 97% or more, 98% or more, 99% or more, or a degree of hydrolysis of 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% refers to polyvinyl alcohol in which 100% of the acetate moieties of the polyvinyl acetate have been hydrolyzed to hydroxyl moieties. Polyvinyl alcohols with a higher degree of hydrolysis are considered to be more water-soluble due to the increased proportion of hydroxyl groups present compared to polyvinyl alcohols with a lower degree of hydrolysis. Without intending to be bound by any theory, it is believed that the addition of hydroxyl groups via the hydrolysis process increases the polarity, thereby increasing the water solubility of the polyvinyl alcohol. In some embodiments, the modified polyvinyl polymer comprises polyvinyl chains produced by modifying polyvinyl alcohol.

[0013] Generally, the modified polyvinyl polymer can include a polyvinyl chain containing one or more units that increase the lipophilicity of the polyvinyl polymer. Without intending to be bound by any theory, it is believed that modification of the hydroxyl moieties of the polyvinyl polymer by reaction with electrophilic molecules can increase the local lipophilicity of portions of the polyvinyl chain.

[0014] Examples of suitable units that can increase the lipophilicity of a polyvinyl polymer include one or more of a unit comprising an ester moiety, a unit comprising an ether moiety, a unit comprising a carboxylic acid moiety, and a unit comprising an ester moiety and a carboxylic acid moiety. In some embodiments, the modified polyvinyl polymer can include units in which one or more of the acetate moiety and the hydroxyl moiety of a polyvinyl alcohol are modified with multiple reactants.

[0015] In some embodiments, the polyvinyl chain of the modified polyvinyl polymer can include one or more units containing an ester moiety formed by the reaction between an anhydride reactant and a hydroxyl group on polyvinyl alcohol. The anhydride reactant can generally include any one or more different anhydrides. Suitable anhydrides can be cyclic or acyclic. The anhydride reactant can include one or more anhydrides that contain no unsaturated carbon-carbon bonds and one or more unsaturated carbon-carbon bonds. The anhydride reactant can include one or more anhydrides that contain no carbon-carbon double bonds and one or more carbon-carbon double bonds. In some embodiments, the modified polyvinyl polymer can include a polyvinyl chain including one or more units containing an ester moiety formed by the reaction between an anhydride reactant and a hydroxyl group on polyvinyl alcohol, where the anhydride reactant does not contain a carbon-carbon double bond. Examples of anhydrides that may be included in the anhydride reactant include one or more of 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.

[0016] Succinic anhydride is generally preferred over maleic anhydride. Without intending to be bound by any theory, it is believed that the carbon-carbon double bond of maleic anhydride provides additional reactivity via conjugate addition. This reactivity is in addition to the reactivity between the anhydride and the hydroxyl group, which produces the ester moiety. Without intending to be bound by any theory, it is believed that the two reaction pathways provided by maleic anhydride can limit control over which reaction pathway prevails by reducing selectivity and making it more difficult to control the properties of the reaction product.

[0017] The anhydride can react with the hydroxyl moieties of the polyvinyl alcohol to form ester moieties on the polyvinyl chain. In some embodiments, the polyvinyl chain of the modified polyvinyl polymer can generally have a structure in which at least a portion of the hydroxyl groups of the polyvinyl alcohol have reacted with the anhydride reactant. In other aspects, the polyvinyl chain can generally have a structure in which all or substantially all of the hydroxyl groups of the polyvinyl alcohol have reacted with the anhydride reactant.

[0018] Succinic anhydride is a relatively small, electrophilic compound that has been observed to be effective in modifying polyvinyl alcohol. Succinic anhydride is also biobased and can be naturally obtained from biological or non-petroleum sources. For example, succinic anhydride can be found in shrubs such as Clerodendrum japonicum and Pycnandra acuminata. The reaction indicated by the downward arrow in Figure 1 illustrates an embodiment of the reaction of polyvinyl alcohol with succinic anhydride, which is represented by the following formula (I): [ka] It has.

[0019] This reaction produces capping units containing both ester and carboxylic acid moieties, as shown in the bottom polyvinyl alcohol chain in Figure 1. Note that Figure 1 shows the acetate (acetyl ester) moiety as "OAc" on the polyvinyl chain. Acetate can also be depicted as CH3COO-.

[0020] The modified polyvinyl polymer generally has the following formula (II): [ka] where X represents a divalent group. In formula (II), the divalent group X can generally have 2 to 6 carbon atoms. In some embodiments, the polyvinyl chain of the modified polyvinyl polymer has the following formula (III): [ka] The unit may include one or more units containing an ester moiety having the formula:

[0021] As shown in formula (III), the unit containing the ester moiety can also contain a carboxylic acid moiety.

[0022] It is also believed that the carboxylic acid moieties formed by the reaction of the anhydride reactant with polyvinyl alcohol can react with hydroxyl groups on the polyvinyl chain. Such a reaction is believed to result in crosslinking. For example, Figure 2 shows an embodiment of the reaction between succinic anhydride and polyvinyl alcohol. As shown, the succinic anhydride first reacts with the hydroxyl groups of the polyvinyl alcohol to form units containing ester and carboxylic acid moieties (shown as intermediate products in Figure 2). The carboxylic acid moieties can then react with additional hydroxyl groups to form crosslinks (shown at the bottom of Figure 2). Such crosslinking is generally believed to occur through reactions between carboxylic acid and hydroxyl moieties on the same polyvinyl alcohol chain, or between carboxylic acid and hydroxyl moieties on different polyvinyl alcohol chains. When the carboxylic acid group crosslinks with the hydroxyl group, an ester and water are produced. Without intending to be bound by any theory, it is generally believed that the resulting ester moieties remain on the polyvinyl alcohol chain, adding to the stability of the polymer. However, the crosslinking process can be reversed because the ester moieties can be hydrolyzed by water. Therefore, the degree of crosslinking in the modified polyvinyl polymer can be determined by controlling the process conditions. The modified polyvinyl polymer can generally have any degree of crosslinking. In some embodiments, the modified polyvinyl polymer can have a crosslinking degree of units containing ester moieties ranging from 70% to 100%, 80% to 99%, 90% to 98%, 91% to 97%, or 92% to 96%. In Figure 2, "OAc" represents an acetate (acetyl ester) moiety on the polyvinyl alcohol chain.

[0023] In some embodiments, the polyvinyl chain of the modified polyvinyl polymer has the following formula (IV): [ka] and one or more cross-linking units having

[0024] In the above formula (IV), X is a divalent group, and the polyvinyl chain of the modified polyvinyl polymer contains the unit (A) shown in brackets. The divalent group X can generally have 2 to 6 carbon atoms. In some embodiments, the polyvinyl chain of the modified polyvinyl polymer contains both the unit (A) and the unit (B) shown in brackets. In other embodiments, the polyvinyl chain of the modified polyvinyl polymer contains the unit (A), the polyvinyl chain of the separate polymer contains the unit (B), and the polyvinyl chain of the separate polymer is derived from polyvinyl alcohol. In some embodiments, one of the following conditions is met for one crosslinking unit of the one or more crosslinking units: the polyvinyl chain of the modified polyvinyl polymer contains the unit (B), or the polyvinyl chain of the separate polymer contains the unit (B), and the polyvinyl chain of the separate polymer is derived from polyvinyl alcohol. In some embodiments, the modified polyvinyl polymer can contain one or more units according to formula (II) and one or more units according to formula (IV).

[0025] In some embodiments, the polyvinyl chain of the modified polyvinyl polymer has the following formula (V): [ka] The crosslinking unit may include one or more crosslinking units having the formula:

[0026] In Formula (V), the polyvinyl chain of the modified polyvinyl polymer comprises unit (A) shown in brackets. In some embodiments, the polyvinyl chain of the modified polyvinyl polymer comprises both unit (A) and unit (B) shown in brackets. In other embodiments, the polyvinyl chain of the modified polyvinyl polymer comprises unit (A), the polyvinyl chain of the separate polymer comprises unit (B), and the polyvinyl chain of the separate polymer is derived from polyvinyl alcohol. In some embodiments, for one crosslinking unit of the one or more crosslinking units, one of the following conditions is met: the polyvinyl chain of the modified polyvinyl polymer comprises unit (B), or the polyvinyl chain of the separate polymer comprises unit (B), and the polyvinyl chain of the separate polymer is derived from polyvinyl alcohol. In some embodiments, the modified polyvinyl polymer can comprise one or more units according to Formula (III) and one or more units according to Formula (V).

[0027] In some embodiments, the modified polyvinyl polymer may comprise a polyvinyl chain containing one or more units containing an ether moiety formed by the reaction between an epoxide reactant and a hydroxyl group of the polyvinyl alcohol. The units containing the ether moiety formed by the reaction between the epoxide reactant and a hydroxyl group of the polyvinyl alcohol may also contain a hydroxyl group. This hydroxyl group may further react with an acetate moiety of the polyvinyl alcohol. Such a reaction is believed to occur via a transesterification reaction between the acetate group and the hydroxyl group of the capping group.

[0028] The epoxide reactant can generally include one or more of ethylene oxide, propylene oxide, butylene oxide, and styrene epoxide. In one approach, the epoxy reactant can be represented by the following formula (VI): [ka] and where R represents a monovalent group containing 0 to 6 carbon atoms. R can generally be aliphatic or aromatic. Propylene oxide is a relatively small electrophilic compound effective for modifying polyvinyl alcohol. In some embodiments, the modified polyvinyl polymer contains one or more units containing an ether moiety produced by the reaction between propylene oxide and the hydroxyl groups of polyvinyl alcohol.

[0029] The reaction indicated by the upward arrow in FIG. 1 represents the reaction of the hydroxyl groups of polyvinyl alcohol with propylene oxide, as shown in formula (VII): [ka] It has.

[0030] The capping group on the left side of the modified polyvinyl polymer (top polyvinyl chain in Figure 1) is the product of a first reaction between propylene oxide and a hydroxyl moiety of polyvinyl alcohol. The modified capping group (annotated "Second Modification") at the center of the modified polyvinyl polymer (top polyvinyl chain in Figure 1) was produced by transesterification between an acetate moiety on the polyvinyl chain and a hydroxyl moiety of a capping group on the same chain, where the acetyl moiety was transferred to the capping group. In some embodiments, the polyvinyl chain of the modified polyvinyl polymer can generally have a structure in which at least a portion of the hydroxyl groups of the polyvinyl alcohol have reacted with an epoxide reactant. In some embodiments, the polyvinyl chain of the modified polyvinyl polymer can have a structure in which all or substantially all of the hydroxyl groups of the polyvinyl alcohol polymer have reacted with an epoxide reactant to form units containing ether moieties. In some forms, the polyvinyl chain of the modified polyvinyl polymer can have a structure in which at least a portion of the units comprising an ether moiety (a capping group formed by reaction between an epoxide reactant and a hydroxyl moiety) are further reacted by transfer of an acetyl moiety from the polyvinyl chain to the capping group. In some embodiments, the polyvinyl chain of the modified polyvinyl polymer can have a structure in which all or substantially all of the units comprising an ether moiety (a capping group formed by reaction between an epoxide reactant and a hydroxyl moiety) are further reacted by transfer of an acetyl moiety from the polyvinyl chain to the capping group.

[0031] The modified polyvinyl polymer can include a polyvinyl chain including one or more units selected from units including an ester moiety formed by the reaction of an anhydride reactant with the hydroxyl groups of polyvinyl alcohol and units including an ether moiety formed by the reaction of an epoxide reactant with the hydroxyl groups of polyvinyl alcohol. In some embodiments, the modified polyvinyl polymer can include a polyvinyl chain including one or more units including an ester moiety formed by the reaction between an acid halide (e.g., an acid chloride) and the hydroxyl groups of polyvinyl alcohol.

[0032] Generally, the modified polyvinyl polymer has the following formula (VIII): [ka] The vinyl alcohol may comprise a polyvinyl chain containing one or more vinyl alcohol units.

[0033] The polyvinyl chain of the modified polyvinyl polymer has the following formula (IX): [ka] It may contain one or more vinyl acetate units of the formula:

[0034] In some embodiments, the polyvinyl chain of the modified polyvinyl polymer can comprise any one or more selected from units comprising an ester moiety selected from formula (II), (III), (IV), (V), units comprising an ether moiety derived from a monomer selected from formula (VI) and (VII), and, optionally, one or more units selected from formula (VIII) and (IX). In some forms, the polyvinyl chain of the modified polyvinyl polymer can comprise any one or more selected from units comprising an ester moiety selected from formula (II), (III), (IV), (V), and, optionally, one or more units selected from formula (VIII) and (IX).

[0035] The modified polyvinyl polymers can have a range of properties and performance capabilities. In some embodiments, the modified polyvinyl polymers can have a weight average molecular weight (Mw) of about 15,000 g / mol to about 200,000 g / mol, about 60,000 g / mol to about 160,000 g / mol, about 90,000 g / mol to about 125,000 g / mol, or about 100,000 g / mol to about 115,000 g / mol. In some embodiments, the modified polyvinyl polymer can have a number average molecular weight (Mn) of about 500 g / mol to about 90,000 g / mol, about 1,000 g / mol to about 80,000 g / mol, about 2,000 g / mol to about 70,000 g / mol, about 15,000 g / mol to about 60,000 g / mol, about 30,000 g / mol to about 45,000 g / mol, or about 35,000 g / mol to about 40,000 g / mol. In some embodiments, the modified polyvinyl polymer can have a polydispersity index (Mw / Mn) of about 2.0 to about 27.0, about 2.0 to about 8.0, about 2.0 to about 4.0, about 2.5 to about 3.5, or about 2.75 to about 2.95. The aforementioned molecular weights and polydispersities can be measured using gel permeation chromatography (GPC).

[0036] Generally, a method for producing a modified polyvinyl polymer can include reacting polyvinyl alcohol having a degree of hydrolysis of at least 50% with one or more anhydride and epoxide reactants. In some embodiments, the polyvinyl alcohol can be dissolved in a first solvent to prepare a first solution, and 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 carry out the reaction. In other embodiments, a single solvent can be used to dissolve the polyvinyl alcohol, and the reactants can be added to the polyvinyl alcohol solution to carry out the reaction.

[0037] Examples of solvents that can be used in the method for producing modified polyvinyl polymers include water, acetonitrile, and mixtures thereof.In some embodiments, polyvinyl alcohol is dissolved in water, and one or more anhydride reactants and epoxide reactants are dissolved in acetonitrile, and then the two solutions are combined to carry out the reaction.In other embodiments, polyvinyl alcohol is dissolved in water, and then one or more reactants are added to an aqueous solution containing polyvinyl alcohol to carry out the reaction.

[0038] Any useful mass or molar ratio of one or more reactants to polyvinyl alcohol can be utilized in the method of making the modified polyvinyl polymer. In one approach, the mass ratio of one or more anhydride reactants and epoxide reactants to polyvinyl alcohol ranges from 0.01:1 to 0.5:1, in another embodiment the mass ratio ranges from 0.05:1 to 0.4:1, in another embodiment the mass ratio ranges from 0.06:1 to 0.3:1, and in yet another approach the mass ratio ranges from 0.1:1 to 0.15:1.

[0039] The process for producing modified polyvinyl polymers can generally be carried out on a batch or continuous basis. A batch process can involve placing all reactants in a reaction vessel and running the reaction to completion. A continuous process is carried out over an extended period of time, continuously producing a reaction product as reactants are fed to the process and reaction conditions are maintained. In some embodiments, the process for producing modified polyvinyl polymers is carried out in a flow reactor containing passages through which polyvinyl alcohol and one or more reactants flow and react. A solution containing polyvinyl alcohol can be pumped through the flow reactor at a specific rate and concentration, and another solution containing one or more reactants, such as an anhydride and / or 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 tuned by adjusting the concentrations and flow rates of the separate solutions.

[0040] Generally, the method for preparing the modified polyvinyl polymer can be carried out at any useful reaction temperature. In some embodiments, the method for preparing the modified polyvinyl polymer comprises reacting polyvinyl alcohol with one or more reactants at a temperature ranging from about 60°C to about 90°C, from about 70°C to about 80°C, from about 75°C to about 95°C, from about 80°C to about 90°C, or from about 82°C to about 88°C.

[0041] The method can further include inducing crosslinking of the modified polyvinyl polymer. Without intending to be bound by any theory, it is believed that the degree of crosslinking can alter the stiffness and strength of the material, as well as the water solubility of the material.

[0042] In some embodiments, polymeric films comprising modified polyvinyl polymers have sufficient tensile strength and elongation to adequately package compatible products. In one embodiment, polymeric films comprising modified polyvinyl polymers have a tensile strength of greater than about 50 N according to ASTM D882. In some embodiments, polymeric films comprising modified polyvinyl polymers have a tensile strength ranging 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.

[0043] In yet another embodiment, the polymeric film comprising the modified polyvinyl polymer has a puncture strength sufficient to adequately package items. In one embodiment, the polymeric film comprising the modified polyvinyl polymer has a puncture strength of greater than about 20 N according to ASTM F1306. In some embodiments, the polymeric film comprising the modified polyvinyl polymer has a puncture strength ranging 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.

[0044] As described above, the modified polyvinyl polymers provided herein can be used to prepare films that can be used in packages or wrapping. Generally, the packaging can encompass or otherwise contain any type of product. In some embodiments, packaging containing the modified polyvinyl polymer can contain food products such as condiments (e.g., ketchup, mayonnaise, mustard, relish, ponzu sauce, oil, vinegar, tartar sauce, frying sauce, and soy sauce), salad dressing, cheese, vegetables, soup, or meat. Examples of food packaging include pouches, sachets, and thermoformed containers. In other forms, the packaging can be formed by heating or by mechanically sealing one or more films.

[0045] Without intending to be bound by any particular theory, it is believed that some forms of modified polyvinyl polymers having a relatively large number of moieties derived from succinic anhydride exhibit a higher level of water resistance compared to modified polyvinyl polymers having a relatively small number of moieties derived from succinic anhydride. Without intending to be bound by any theory, it is believed that modified polyvinyl polymers having a large number of residual hydroxyl groups unmodified with anhydride reactants serve to increase the water solubility of the polymer, while modified polyvinyl polymers having relatively fewer hydroxyl groups are relatively less soluble. Therefore, it is contemplated that the solubility of modified polyvinyl polymers can be adjusted by increasing or decreasing the relative degree of modification with anhydride reactants.

[0046] In some embodiments, the polymer film can generally comprise one or more modified polyvinyl polymers. In some embodiments, the packaging can generally comprise one or more modified polyvinyl polymers or one or more polymer films comprising one or more modified polyvinyl polymers, and optionally additional polymers or polymer films that do not comprise modified polyvinyl polymers. The packaging comprising the modified polyvinyl polymer can generally contain products with any combination of properties.

[0047] In some approaches, the food sachet may comprise a sachet body comprising a film comprising a modified polyvinyl polymer. The food may be enclosed in the sachet body. In some embodiments, a condiment is enclosed in the sachet body.

[0048] The packaging film can include one or more additional layers to provide desired properties to the overall packaging film, such as tensile strength, puncture strength, water vapor permeability, and / or oxygen permeability.

[0049] In one approach, the packaging material has a structure and composition that is compatible with the packaged item to provide a desired shelf life. In various embodiments, this compatibility can prevent or reduce premature deterioration and mechanical weakness of the packaging material that comes into contact with the packaged item, prevent or reduce materials from leaching out of the packaging material and coming into contact with the packaged item, or prevent or reduce moisture loss from the packaging material through the packaging material.

[0050] In some embodiments, the packaging may comprise a polymeric film comprising one or more modified polyvinyl polymers, where the one or more packaging materials and polymers have one or more properties (e.g., chemical composition and mechanical properties) tailored for contact with a particular packaged item.

[0051] Packaging materials made from modified polyvinyl polymers can include a single film layer, or in another embodiment, two or more film layers. Similarly, modified polyvinyl polymers can be layered with other materials, such that the modified polyvinyl polymer can be an inner layer, an outer layer, and / or a middle layer. Furthermore, multiple layers of modified polyvinyl polymer material can be used alone or in combination with other layers. Examples of other layers include, but are not limited to, ethyl cellulose, soy protein, and other biopolymers.

[0052] In some embodiments, the packaging material can encompass or otherwise contain a product having a moisture content ranging from about 1% by weight (wt%) to about 99% by weight, from about 5% to about 95% by weight, from about 10% to about 90% by weight, from about 20% to about 80% by weight, from about 30% to about 70% by weight, from about 40% to about 60% by weight, or from about 45% to about 55% by weight. In some forms, the sachet comprises a modified polyvinyl polymer and encapsulates a condiment such as ketchup having a moisture content ranging from about 60% to about 70% by weight, or in another embodiment, from about 63% to about 70% by weight.

[0053] The packaging material comprises a modified polyvinyl polymer and has a water activity of 0.05g or less. w In some embodiments, the packaging material can encapsulate a product having an a in the range of about 0.05 to about 0.99, about 0.1 to about 0.98, about 0.2 to about 0.9, about 0.3 to about 0.8, about 0.4 to about 0.7, or about 0.5 to about 0.6. w In some embodiments, the sachet may contain a modified polyvinyl polymer having an a of about 0.91 to about 0.98, about 0.92 to about 0.97, about 0.93 to about 0.96, or about 0.94 to about 0.95. w The ketchup includes ketchup having the formula:

[0054] The packaging comprises a modified polyvinyl polymer and can enclose a product having any Brix (°Bx). In some embodiments, the packaging can encompass or otherwise contain a product having a Brix of about 0.5°Bx to about 95°Bx, about 1°Bx to about 90°Bx, about 5°Bx to about 85°Bx, about 10°Bx to about 80°Bx, about 20°Bx to about 70°Bx, about 30°Bx to about 60°Bx, or about 40°Bx to about 50°Bx. In some embodiments, the sachet comprises a modified polyvinyl polymer and contains ketchup having a Brix of about 30°Bx to about 40°Bx, about 31°Bx to about 39°Bx, about 32°Bx to about 38°Bx, about 33°Bx to about 37°Bx, or about 34°Bx to about 36°Bx.

[0055] The packaging material comprises a modified polyvinyl polymer as provided herein and can generally encompass a product having a basic, acidic, or neutral pH. In some embodiments, the packaging material can encompass or otherwise contain a product having a pH of about 3 to about 9, about 4 to about 8, about 4.5 to about 5, about 6 to about 7, about 3.5 to about 7.5, about 4 to about 7, about 4.5 to about 6.5, or about 5 to about 6. In some forms, the sachet comprises a modified polyvinyl polymer and encompasses a ketchup having a pH of about 3 to about 4.5, about 3 to about 4, about 3.1 to about 3.9, about 3.8 to about 3.99, or less than about 4.

[0056] In one particular approach, ketchup having a pH in the range of about 3.2 to about 4.0 is enclosed in a sachet body.

[0057] In one approach, a hydrophilic layer can be used as the inner layer of the food packaging film, while the outer layer can have a different composition that allows for more rapid degradation upon contact with water and / or soil.

[0058] Coatings can also be used to modify the properties and functionality of modified polyvinyl polymer materials, especially when used as food packaging. Such coatings include, but are not limited to, waxes such as beeswax, and other biopolymers.

[0059] In one approach, a packaging material (package) includes a first film containing a modified polyvinyl polymer with suitable food contact properties and a second film containing an unmodified polyvinyl alcohol polymer that is prone to rapid dissolution upon contact with moisture. Examples of unmodified polyvinyl alcohol polymers include those described herein, including those with any degree of hydrolysis but without further capping or modification of the hydroxyl and acetate moieties. In some configurations, a multilayer package includes an inner film containing a modified polyvinyl polymer in direct contact with the packaged product and an outer film containing an unmodified polyvinyl alcohol polymer that is not directly exposed to the product. In other configurations, a multilayer package includes an inner film containing an unmodified polyvinyl alcohol in direct contact with the packaged product and an outer film containing a modified polyvinyl polymer that is not directly exposed to the product.

[0060] Figure 3A shows one embodiment of a food sachet comprising a sachet body 2 with seals 4 on three sides. The sachet was formed by folding a film and sealing the three sides. Figure 3B shows a cross-section of the food sachet of Figure 3A along line A-A. In Figure 3B, a first film 6 comprises a modified polyvinyl polymer and contacts an edible product 8 (e.g., ketchup) disposed inside the sachet body. A second film 10 comprises an unmodified polyvinyl alcohol polymer and forms the exterior of the sachet body. While the sachet shown has seals on three sides, it will be understood that other numbers of seals, such as two seals, four seals, etc., can be used.

[0061] FIG. 3C is an enlarged cross-sectional view of the food sachet embodiment shown in FIG. 3B, taken at box B.

[0062] Various examples were prepared and tested to compare the influence of starting materials, manufacturing methods, and other variables related to the materials.

[0063] Example The following examples are offered to illustrate various embodiments without limiting effect.

[0064] Example 1 - Modified polyvinyl polymer containing units formed by reaction of succinic anhydride with the hydroxyl groups of polyvinyl alcohol A polyvinyl alcohol solution was prepared by dissolving 1.0 gram of granular PVOH-418 (hot water soluble polyvinyl alcohol with a degree of hydrolysis of 92% from Aquapak Polymers Ltd., Birmingham, UK) in 10 mL of water. An anhydrous solution was prepared by dissolving 0.5 g of succinic anhydride (Merck / Sigma Aldrich) in 5 mL of acetonitrile.

[0065] A flow reactor assembly containing a peristaltic pump delivered the polyvinyl alcohol solution and anhydride solution to a T-mixer. The T-mixer turbulently mixed the solutions into a homogeneous reaction mixture and fed it into the reactor. The reactor contained two reactor cores composed of PFA (perfluoroalkoxyalkane) tubing coils. A reactor control unit controlled the temperature and residence time of the reaction mixture within the reactor cores. The total residence time of the reaction mixture through both cores was 10 to 30 minutes at a temperature of 60 to 70°C. The reaction mixture remained homogeneous throughout the residence time without fouling or clogging the reactor tubes. Product collection vials collected the polymer material exiting 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 for packaging materials.

[0066] Example 2 - Modified polyvinyl polymer containing units produced by reaction of hydroxyl groups of polyvinyl alcohol ("POxide" film) with propylene oxide A polyvinyl alcohol solution was prepared by dissolving 1.0 gram of PVOH-418 (hot water-soluble polyvinyl alcohol with a degree of hydrolysis of 92% from Aquapak Polymers Ltd., Birmingham, UK) in 10 mL of water. An epoxide solution was prepared by mixing 0.5 mL of propylene oxide with 5 mL of acetonitrile. The polyvinyl alcohol solution and epoxide solution were fed into the reactor assembly described in Example 1 and subjected to the same reaction conditions and drying procedure used in Example 1.

[0067] Figure 4 shows two Petri dishes. The left dish contains the product of Example 2, which has a gel-like, clear, and colorless appearance. The right dish contains the product of Example 1, which has an opaque, rubbery appearance. Both modified polymers provided flexible films and were completely soluble in water at 40°C. The resulting films can be used in packaging materials.

[0068] IR Test Infrared spectroscopy (IR) was used to evaluate the differences in vibrational frequencies associated with acetate moieties in unmodified polyvinyl alcohol (PVOH-418) compared to the two modified polyvinyl polymers of Examples 1 and 2. IR spectroscopy also evaluated the appearance of vibrations associated with units produced by reacting succinic anhydride in Example 1 and propylene oxide in Example 2. IR spectra were obtained using a Bruker Platinum spectrometer (neat, ATR sampling).

[0069] Figure 5 is the IR spectrum of unmodified PVOH-418, Figure 6 is the IR spectrum of Example 1, and Figure 7 is the IR spectrum of Example 2. Compared to the band at 1714 cm in Figure 5, the spectrum in Figure 6 shows a strong band at 1691 cm associated with the structure resulting from modification with succinic anhydride. Compared to Figure 5, the spectrum in Figure 7 shows an additional broad band at 1644 cm associated with modification with propylene oxide.

[0070] Example 3 - Modified polyvinyl polymer containing units prepared by reaction of succinic anhydride with the hydroxyl groups of polyvinyl alcohol Suc1 film A polyvinyl alcohol solution was prepared by dissolving / suspending 30 g of PVOH-418 in 300 mL of deionized water. This solution was placed in a 500 mL Schott glass bottle containing a 2 cm magnetic stir bar, which was then placed on an IKA hotplate with magnetic stirring. Next, 4 grams 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 cloudy but produced a clear solution within 1 hour.

[0071] The modified polyvinyl polymer was poured into four 40 x 20 cm plastic storage boxes without pre-cooling, aiming for approximately 70 grams of product per box. After 2 days of dry evaporation in a light-free fume hood, the film was removed from the boxes and stored between sheets of paper to avoid curling.

[0072] Suc2 Film 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 to obtain a sample film.

[0073] Suc3 Film The same procedure as in Example "Suc1" above was carried out, except that 6 g of solid succinic anhydride was added to the polyvinyl alcohol solution. A sample film was obtained.

[0074] POxide Film The same procedure as in Example 2 above was carried out using propylene oxide. Sample films were obtained. Limited testing was carried out on propylene oxide ("POxide") films.

[0075] Dried films of the Suc1, Suc2, Suc3, and Poxide samples were peeled from the casting box. Upon peeling, these films were typically completely transparent, but within a few days they may develop a slightly opaque appearance, indicating further drying. After peeling, the films continued to dry and did not have a sticky quality.

[0076] Samples Suc1, Suc2, Suc3, and Poxide were compared to conventional polyvinyl alcohol products: hot water-soluble PVOH ("HPWS PVOH," sold by Aquapak as 30164P) and warm water-soluble PVOH ("WWS PVOH," sold by Aquapak as 33104P). The average gauge of the films of Examples Suc1, Suc2, Suc3, Poxide, HWS PVOH, and WWS PVOH is shown in Table 1.

[0077] [Table 1]

[0078] test IR Test Infrared spectroscopy (IR) was used to evaluate the vibrational frequencies generated by Suc1. The IR spectrum of Suc1 is shown in Figure 8. Comparison of the IR spectrum of unmodified PVOH-418 shown in Figure 5 with the spectrum of Suc1 in Figure 8 shows a clear change in the carbonyl group stretching region in the range of 1600–1800 cm⁻¹, consistent with the introduction of the moiety upon reaction with succinic anhydride. More specifically, a shift from approximately 1714 cm⁻¹ for PVOH-418 to approximately 1703 cm⁻¹ for Suc1 is observed. IR spectra were obtained using a Bruker Platinum spectrometer (neat, ATR sampling).

[0079] The samples were then tested for disintegration under composting conditions, cold dispersibility / solubility, and hot dispersibility / solubility. 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.

[0080] Dispersibility and solubility in cold water Cold water dispersibility tests were performed by mixing at least 1 g (dry basis) of Suc1, HWS PVOH, and WWS PVOH films (having dimensions of at least 25 mm × 25 mm) with 1 L of tap water in a 2 L beaker under stirring at 150 rpm (magnetic stirring rod). The films were stirred in the dark at 25°C ± 2°C for 16 hours. After this period, the films were subjected to determination of the water-dispersible fraction (D) by sieving on a 10 mm sieve.

[0081] The test was carried out in accordance with EN 14987 Plastics - Evaluation of disposability in wastewater treatment plants - Test scheme for final acceptance and specifications (2006). The test was carried out in triplicate.

[0082] Table 2 shows the cold water dispersibility (D) measurements of the samples. To be considered cold water dispersible for the purposes of this specification, at least 90% of the material must pass through a 10 mm sieve. To be soluble, more than 90% of the material must pass through a 0.45 μm filter. Also shown in Table 2 are the pH at the start and end of the test (16 hours). According to EN 14987 (2006), the initial pH must be neutral. No POxide samples were tested.

[0083] [Table 2]

[0084] At the end of the cold water dispersibility test (after 16 hours), a clear solution was obtained for Suc1. After 16 hours of stirring (end of test), no significant change in the pH of Suc1 was observed. There was no residue on the 10 mm sieve, and the reactor contents were directly filtered through a 0.45 μm filter. Filtration above 0.45 μm proceeded very slowly, with only a few drops passing through the filter after approximately 3 hours. The Suc1 sample was determined to be cold water dispersible but not cold water soluble.

[0085] The solubility of HPWS PVOH was not evaluated due to insufficient dispersibility. The reactor contents of the test material, WWS PVOH, were filtered through a 0.45 μm or larger filter. Filtration proceeded very slowly, with only a few drops passing through the filter after several hours. Therefore, filtration was not possible, and the test material could not be characterized as cold-water soluble. From the results of this test, it can be concluded that HWS PVOH is neither cold-water dispersible nor cold-water soluble. The test material, WWS PVOH, is cold-water dispersible but not cold-water soluble. There was a slight increase in pH after 16 hours for both the HWS PVOH and WWS PVOH materials.

[0086] Dispersibility and solubility in hot water Hot water dispersibility tests were performed by mixing at least 1 g (dry basis) of film (having dimensions of at least 25 mm x 25 mm) with 1 L of tap water in a 2 L beaker under stirring at 150 rpm. The film was stirred in the dark at 60°C ± 2°C for 16 hours. After this period, the suspension was subjected to determination of the water-dispersible fraction (D) by sieving on a 10 mm screen. The total test time was 16 hours, and the test was performed in triplicate.

[0087] According to EN 14987(2006), a material that, after dissolving in hot water, yields a dispersible fraction of ≥ 90% is considered to be hot-water dispersible. Furthermore, according to EN 14987(2006), the initial pH must be neutral. Table 3 shows the results of the hot-water dispersibility test. Table 3 shows the amount of test material added to 1 L of tap water at the start after drying at 50°C and the amount of test material retained on a 10 mm sieve after 16 hours of stirring at 60°C and 150 rpm.

[0088] [Table 3]

[0089] Hot water solubility was measured by filtration through a 0.45 μm filter. To be hot water soluble, a soluble fraction of ≧90% must be obtained after filtration through a 0.45 μm filter.

[0090] The Suc1 film was dispersible and soluble at 60°C. At the end of the hot water dispersibility test (16 hours), a clear solution was obtained for Suc1. A slight decrease in pH was measured in the Suc1 reactor at the end of the test (16 hours), from 8.6 to 8.2-8.3. Since there was no residue on the 10 mm sieve, the reactor contents were directly filtered through a 0.45 μm filter. Filtration proceeded very quickly, allowing the solubility to 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 met the dispersibility and solubility criteria specified in EN 14987 (2006) and can be defined as hot water dispersible and soluble.

[0091] After 16 hours, a clear solution was obtained for Suc3. No residue was found on the 10 mm sieve. Because no small particles were recovered from the sieve for sample Suc3, 100% dispersibility was calculated. The reactor contents were then filtered through a 0.45 micron filter. Filtration proceeded slowly. After more than an hour, only a few droplets passed through the filter. Therefore, the Suc3 film could not be characterized as being hot-water soluble. Therefore, the Suc3 film was characterized as being hot-water dispersible but not hot-water soluble. The pH significantly decreased from 8.0-8.1 to 6.0-7.0.

[0092] The HWS PVOH pieces tested were rolled up but still largely intact and retained on the 10 mm sieve. The solubility of the HWS PVOH was not evaluated due to poor dispersibility. The results in the table above show that 73.1% of the original weight of the HWS PVOH was retained on the 10 mm sieve, which corresponds to a dispersibility of 26.9% ± 2.0%. The pH was very stable over 16 hours.

[0093] In the case of WWS PVOH, no particles were recovered from the sieve, so a dispersibility of 100.0% was calculated. The reactor contents of WWS PVOH were filtered at 0.45 μm or greater. Filtration proceeded very slowly, with only a few drops passing through the filter after several hours. This made filtration impossible, and the test material could not be characterized as hot-water soluble. The pH remained very stable over 16 hours.

[0094] The results of this test showed that HWS PVOH was not hot water dispersible and not hot water soluble. The test material WWS PVOH was hot water dispersible but not hot water soluble.

[0095] Additional solubility testing Solubility tests in warm water (40° C.) were performed on film samples of Examples Suc1, Suc2, Suc3, and Poxide. Films (membrane pieces) were added to water at 40° C. The results are shown in Table 4.

[0096] [Table 4]

[0097] Films containing the smallest and largest amounts of units formed by reaction between succinic anhydride and hydroxyl groups of polyvinyl alcohol (Suc2 and Suc3) showed faster dissolution than films containing intermediate amounts of such units (Suc1).

[0098] All inventive examples exhibited rapid dissolution, indicating that chemical modification of the PVOH polymer did not result in a loss of water solubility.

[0099] Disintegration under composting conditions Materials were placed in a compost chamber and tested for soil-based disintegration. During home composting, the high temperatures (>50°C) achieved during industrial composting processes are rarely reached. Therefore, materials should demonstrate disintegration at ambient temperatures sufficient for home composting to be considered feasible. 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 minor modifications.

[0100] The decay of the samples was assessed qualitatively. The test lasted for 16 weeks. The test materials were placed in slide frames, mixed with compost, and incubated in the dark at 28°C ± 2°C. Tests were performed twice for each test item. The compost consisted of an 80 / 20 mixture of <10mm mature compost and freshly ground plant, garden, and fruit waste (VGF). The compost was stirred periodically and moistened as needed. At the same time, the appearance of the slide frames with the test materials was evaluated.

[0101] The mature compost was a mixture of mature VGF and green compost. The VGF compost was derived from the organic fraction of municipal solid waste and was further stabilized and aerated in a pilot-scale composting bin under controlled laboratory conditions to obtain a fully mature compost. The age of the VGF compost was 16 weeks. The green compost was obtained from garden waste, prunings, tree roots, and stubble and was stabilized in a full-scale composting plant. The compost was mixed in a ratio of 50% VGF compost and 50% green compost. The mixture in the composting reactor was turned manually at regular intervals while the decay of the test samples was visually monitored.

[0102] Composting disintegration of films of Suc1 (approximately 35 microns thick, as measured with a digital micrometer) was evaluated. After two weeks, small holes began to appear in the test material on several slide frames. It was noted that the test material was very sticky. No significant progress in disintegration was observed over the following weeks. After 12 weeks of composting, small holes were observed in the test material on several slide frames, but the test material in the main part of the slide frames remained intact. Disintegration progressed slowly, and after 16 weeks of composting at ambient temperature, small holes were present in the test material on the main part of the slide frames. However, the test material in several slide frames remained completely intact. Based on an assessment of the remaining surface of the test material within the slide frames, it was concluded that the test material had an average disintegration rate of <81%.

[0103] The composting disintegration results of Suc3 film (approximately 76 microns thick) were also evaluated. After one week of composting, the test material turned brown and became elastic. No signs of disintegration were observed over the following weeks. After 20 weeks, the test material in all slide frames remained completely intact. After two weeks, small holes began to appear in the test material in several slide frames. After 26 weeks of composting, small holes were present in the test material in some slide frames, while the test material in the main parts of the slide frames remained completely intact. No further progress was observed over the following weeks. After 32 weeks (the end of the test), small holes were observed in the test material in several slide frames. However, the test material in the majority of the slide frames remained completely intact. Based on the determination of the remaining surface area of ​​the test material in the slide frames, it can be concluded that the test material Suc3 is characterized by a 0% disintegration rate after 32 weeks of composting at ambient temperature.

[0104] In comparison, two unmodified PVOHs (Aquapak 30164P (hot water soluble, 35 microns) and Aquapak 33104P (warm water soluble, 29 microns) remained completely intact (0% disintegration) at 16 weeks. The HWS film sample (approximately 35 microns thick) and the WWS film sample (approximately 29 microns thick) showed no signs of disintegration during the test. After 26 weeks, the test material remained completely intact on all slide frames. The test material was characterized by a 0% disintegration rate after 26 weeks of composting at ambient temperature.

[0105] The overall results for disintegration, cold dispersibility / solubility, and hot dispersibility / solubility are summarized in Table 5 below:

[0106] [Table 5]

[0107] OTR and WVTR tests Oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) were tested for films of Examples Suc1, Suc2, Suc3, and Poxide. Oxygen transmission rates were measured at 23°C and 0% relative humidity based on tests according to ASTM D3985 and ASTM F1927. The target oxygen transmission rate for the samples was <10 cc / m 2 / day. The water vapor transmission rate was measured at 38°C and 90% relative humidity using a test based on ASTM F1249. The water vapor transmission rate was 13.8 cc / m² over one week. 2 / day or less, 6.57cc / m over 2 weeks 2 / day or less.

[0108] Table 6 shows the OTR and WVTR exhibited by films of Examples Suc1, Suc2, Suc3, and Poxide compared to conventional PVOH alone (Comparative). The OTR results showed average performance across four variables. When used as the only layer of packaging film, the Suc1, Suc2, Suc3, and Poxide samples did not have sufficient WVTR and OTR values ​​for use in sachets containing ketchup. The average gauge of the measured samples was 141 microns for the Suc1 sample, 42 microns for the Suc2 sample, 95 microns for the Suc3 sample, and 52 microns for the Poxide sample.

[0109] [Table 6]

[0110] Films of Examples Suc1, Suc2, Suc3, and Poxide were tested for tensile strength and elongation, as well as puncture resistance, compared to unmodified PVOH. The target tensile strength and elongation were at least 50 N, and the target puncture resistance was at least 20 N. Table 7 shows the tensile strength and elongation, as well as puncture resistance, exhibited by films of Examples Suc1, Suc2, Suc3, and Poxide. While the tensile strength and puncture resistance were considered satisfactory, the elasticity ranged from poor to good for the examples.

[0111] [Table 7]

[0112] Films of Examples Suc1, Suc2, Suc3, and Poxide were used to form sealed sachets enclosing ketchup. Sachets formed from Suc1 burst when filled with ketchup. Sachets formed from Suc2 could not be filled with ketchup because the films stuck together. Sachets formed from Suc3 had a high rate of ketchup loss and shrunk two hours after filling. Sachets formed from Poxide shrunk, losing all of the ketchup moisture. Thus, while samples Suc1, Suc2, Suc3, and Poxide are not suitable for use in single-layer sachets by themselves, they can be combined with other polymer films or coatings to provide sachets that can be used to hold food.

[0113] Example 4 - Modified polyvinyl polymer containing units prepared by reaction of succinic anhydride with the hydroxyl groups of polyvinyl alcohol WWS‐Suc A polyvinyl alcohol solution was prepared by dissolving / suspending 30 g of PVOH-418 in 300 mL of deionized water. This 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. Next, 4 grams of solid succinic anhydride was added to the polyvinyl alcohol solution, and the mixture was vigorously stirred at 80 °C for 5 hours. Two samples of the WWS-Suc polymer were tested for molecular weight using GPC with the following setup: Instrument Viscotek GPC Max Column: 2 x 30cm Agilent OH60 GPC columns Eluent: Water + 0.2m sodium nitrate Flow rate 1.0ml / min Detection RI Temperature 40℃

[0114] Samples were injected using automatic sample injection. Viscotek's "Omnisec" software was used for data collection and subsequent data analysis.

[0115] HWS‐Suc A polyvinyl alcohol solution was prepared by dissolving / suspending 30 g of PVOH-E103 (hot-water-soluble polyvinyl alcohol from Aquapak Polymers Ltd., Birmingham, UK) in 300 mL of deionized water. This 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. Next, 4 grams of solid succinic anhydride was added to the polyvinyl alcohol solution, and the mixture was vigorously stirred at 80 °C for 5 h. A sample of the HWS-Suc polymer was tested for molecular weight using the same equipment and procedure used to test the two WWS-Suc samples.

[0116] Table 8 shows the molecular weight moments of the sample injections of the two WWS-Suc samples and the HWS-Suc sample.

[0117] [Table 8]

[0118] The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only, and not by way of limitation. While particular embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications can be made without departing from the broader aspects of applicant's contribution. The actual scope of protection sought is intended to be defined in the following claims, viewed in their proper perspective based on the prior art.

Claims

1. a modified polyvinyl polymer comprising a polyvinyl chain containing one or more units containing an ester moiety formed by the reaction of an anhydride reactant with the hydroxyl groups of polyvinyl alcohol; A polymer film comprising:

2. 10. The polymeric film of claim 1, wherein the anhydride reactants comprise one or more of succinic anhydride, acetic anhydride, propionic anhydride, adipic anhydride, glutaric anhydride, pimelic anhydride, suberic anhydride, and malonic anhydride.

3. The one or more units comprising an ester moiety are represented by formula (II): 【Chemistry 1】 (II) and X represents a divalent group; The polymer film according to claim 1 or 2.

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

5. The one or more units comprising an ester moiety have the formula (III): 【Chemistry 2】 (III) The polymer film according to any one of claims 1 to 4, comprising the structure according to

6. The polyvinyl chain of the modified polymer has the formula (IV): 【Transformation 3】 and one or more bridging units having the structure according to X is a divalent group, the polyvinyl chain of the modified polyvinyl polymer contains the unit (A) shown in brackets, and For one crosslinking unit of the one or more crosslinking units: The polyvinyl chain of the modified polyvinyl polymer comprises the unit (B) shown in brackets, or the polyvinyl chain of the other polymer comprises units (B) and the polyvinyl chain of the other polymer is derived from polyvinyl alcohol; The polymer film according to any one of claims 1 to 5, wherein the polymer film satisfies one of the above conditions.

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

8. The polyvinyl chain of the modified polymer has the formula (V): 【Chemistry 4】 and one or more bridging units having the structure according to The polyvinyl chain of the modified polyvinyl polymer comprises the unit (A) shown in brackets, and For one crosslinking unit of the one or more crosslinking units: The polyvinyl chain of the modified polyvinyl polymer comprises the unit (B) shown in brackets, or the polyvinyl chain of the other polymer comprises units (B) and the polyvinyl chain of the other polymer is derived from polyvinyl alcohol; The polymer film according to any one of claims 1 to 7, wherein the polymer film satisfies one of the above conditions.

9. The polyvinyl chain has the formula (VIII): 【Transformation 5】 (VIII) 9. The polymer film of claim 1, further comprising one or more vinyl alcohol units having the structure:

10. The polyvinyl chain has the formula (IX): 【Transformation 6】 (IX) 9. The polymer film of claim 1, further comprising one or more vinyl acetate units having the structure:

11. The polyvinyl chain has the formula (VIII): 【Transformation 7】 (VIII), and one or more vinyl alcohol units having a structure according to formula (IX): 【Transformation 8】 (IX) one or more vinyl acetate units having the structure The polymer film of any one of claims 1 to 8, further comprising:

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

13. 10. The polymer film according to claim 1, wherein the polyvinyl chains are derived from a polyvinyl alcohol polymer with a degree of hydrolysis between 90% and 100%.

14. 10. 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 between 92% and 100%.

15. 15. The polymer film of claim 12, wherein the polyvinyl chains have a structure in which about 50 to about 100% of the hydroxyl groups of a polyvinyl alcohol polymer have reacted with an anhydride reactant to form units containing ester moieties.

16. a sachet body comprising the polymer film of any one of claims 1 to 15 and a second film; The food enclosed in the sachet body, A food sachet comprising:

17. 17. A food sachet according to claim 16, wherein the food has an acidic pH.

18. 17. A food sachet according to claim 15 or 16, wherein the food has a Brix in the range of about 15°Bx to about 50°Bx.

19. A food sachet according to any one of claims 16 to 18, wherein the food product has a water activity in the range of from about 0.90 to about 0.

99.

20. A food sachet according to any one of claims 16 to 19, wherein the food product has a moisture content in the range of about 50 wt% to about 95 wt%.

21. A food sachet according to any one of claims 16 to 20, wherein the food comprises a seasoning.

22. 22. The food sachet of claim 21, wherein the condiment is ketchup, mayonnaise, mustard, relish, ponzu sauce, oil, vinegar, tartar sauce, fry sauce, or soy sauce.

23. 22. The food sachet of claim 21, wherein the condiment comprises ketchup having a pH in the range of 3.8 to 4.

0.

24. A food sachet according to any one of claims 16 to 23, wherein the second film comprises an unmodified polyvinyl alcohol polymer, the polymer film being in contact with the food enclosed within the sachet body, and the second film forming at least part of the exterior of the sachet body.

25. units containing an ester moiety formed by reaction of an anhydride reactant with a hydroxyl group of polyvinyl alcohol; and 1. A unit comprising an ether moiety formed by reaction of an epoxide reactant with a hydroxyl group of polyvinyl alcohol, said epoxide reactant having formula (VI): 【Chemistry 9】 (VI) wherein R represents a monovalent group containing 0 to 5 carbon atoms; A polymer film comprising a modified polyvinyl polymer comprising polyvinyl chains, the modified polyvinyl polymer comprising one or more of:

26. 26. The polymer film of claim 25, wherein the units containing ether moieties are produced by the reaction of propylene oxide with hydroxyl groups of polyvinyl alcohol.

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

28. 28. The method of claim 27, wherein the anhydride reactants comprise one or more of succinic anhydride, acetic anhydride, propionic anhydride, adipic anhydride, glutaric anhydride, pimelic anhydride, suberic anhydride, and malonic anhydride.

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

30. 30. The method of any one of claims 27 to 29, wherein the mass ratio of said anhydride reactant to said polyvinyl alcohol is in the range of 0.01:1 to 0.5:

1.

31. The method comprises: Formula (II): 【Chemistry 10】 (II) 31. The method of any one of claims 27 to 30, wherein a modified polyvinyl polymer is produced having a polyvinyl chain comprising one or more units having the structure:

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

33. The one or more units have the formula (III): 【Chemistry 11】 (III) 33. The method of claim 31 or claim 32, having the structure of

34. The polyvinyl chain has the formula (VIII): 【Chemistry 12】 (VIII) The method of any one of claims 31 to 33, further comprising one or more vinyl alcohol units having the structure:

35. The polyvinyl chain has the formula (IX): 【Chemistry 13】 (IX) The method of any one of claims 31 to 33, further comprising one or more vinyl acetate units having the structure:

36. The polyvinyl chain has the formula (VIII): 【Chemistry 14】 (VIII), and one or more vinyl alcohol units having a structure according to formula (IX): 【Chemistry 15】 (IX) one or more vinyl acetate units having the structure The method of any one of claims 31 to 33, further comprising:

37. 37. The process of any one of claims 27 to 36, wherein the reaction of the polyvinyl alcohol with the anhydride reactant is carried out as a batch process.

38. 37. The method of any one of claims 27 to 36, wherein the reaction of the polyvinyl alcohol with the anhydride reactant is carried out as a continuous process.

39. 39. The method of claim 38, wherein the continuous process comprises feeding the polyvinyl alcohol and the anhydride reactant to a flow reactor.

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