Multilayered polyvinyl alcohol film and method for producing the same

Abstract

Provided are a water-soluble film and related packets. More specifically, provided are a multi-layered, water-soluble polyvinyl alcohol film, and a simultaneous casting process for producing such a film. **Solution**: Disclosed herein are a simultaneous co-casting process for preparing a multi-layer water-soluble film, a multi-layer film prepared by the simultaneous co-casting process, a multi-layer film including a foamed layer, methods for making them, related articles made therefrom, and related uses thereof.

Description

Technical Field

[0001] Cross - Reference to Related Applications Claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 63 / 337,956, filed on May 3, 2022, the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure generally relates to water - soluble films and related packets. More specifically, the present disclosure relates to multilayered, water - soluble polyvinyl alcohol films, and a co - casting process for making such films.

Background Art

[0003] Water - soluble polymer films are commonly used as packaging materials that simplify the dispensing, injection, dissolution, and introduction of the materials to be delivered. Consumers can directly add this pouched composition to a mixing container such as a bucket, sink, or washing machine. Advantageously, this provides accurate introduction while eliminating the need for the consumer to measure the composition. In addition, water - soluble polymer film packaging can keep powerful chemicals away from the consumer's hands and prevent the consumer from coming into contact with harsh chemicals. This pouched composition can also reduce the hassle associated with dispensing a similar composition from a container, such as pouring the composition from a bottle. In short, soluble pre - measured polymer film pouches provide convenience and safety for consumer use in various applications.

[0004] Some of the water-soluble polymer films used to make currently commercially available pouches interact with (i.e., block) other pouches, are not visually appealing due to having a high haze %, or do not exhibit sufficiently high sealability or solubility, for example, after storage. For example, a pouch may exhibit a low haze %, but may be too easy to block with other pouches. Or, a pouch may exhibit good solubility with commonly used water-soluble films, such as certain polyvinyl alcohol films, but may have poor water tightness. Films with poor water tightness are susceptible to early failure of the pouch or packet seal and release of the contents before use. In another type of problem, a pouch may have good sealability but poor solubility in cold water. Such reduced solubility can, for example, leave a significant amount of residue (e.g., more than 50%) after the contents of the pouch have been dispersed. In addition, chemical incompatibility between the film constituting the pouch and one or more materials packed therein can cause undesirable interactions or chemical reactions. For example, the interaction between the film constituting the pouch and the material enclosed therein can cause degradation or breakage of the film, resulting in leakage of the pouch contents, degradation of the pouch contents, perhaps the generation of gas by-products leading to rupture of the pouch, or cross-linking of the film resulting in film cracking during storage.

[0005] In some instances, modifying a water-soluble film to improve one property can have a negative impact on other properties. For example, a blocking agent can be incorporated into the film or applied to the film surface to improve the blocking properties of the film, but the addition of such a blocking agent typically increases the haze of the film. It would be advantageous to produce a water-soluble film that can provide a combination of beneficial chemical and / or physical properties that are typically incompatible with each other.

[0006] The multilayer polyvinyl alcohol film is produced, for example, by melt coextrusion as in U.S. Patent No. 8,597,796 B2. For solution casting, for example, as in U.S. Patent Application Publication No. 2009 / 0196908 A1, U.S. Patent Nos. 4,765,916 and 9,744,695 B2, and International (PCT) Publication No. WO1998 / 021118 A1 (the disclosure of which is incorporated herein by reference), after the first casting step, a drying process to remove the carrier solvent follows, and then a second layer is cast to form a two-layer film. Previous literature has also described making multilayer constructs, for example, as in U.S. Patent No. 6,776,287 (the disclosure of which is incorporated herein by reference), by laminating two films or by continuous casting. SUMMARY OF THE INVENTION

[0007] One aspect of the present disclosure provides a water-soluble film comprising a plurality of layers in continuous contact with each other, the film being prepared by a simultaneous solution co-casting process.

[0008] Another aspect of the present disclosure provides a multilayer water-soluble film comprising a first layer containing a blend of polyvinyl alcohol (PVOH) homopolymer and PVOH copolymer and a second layer comprising a blend of PVOH homopolymer. Films according to this aspect can optionally provide both a high barrier to water vapor transmission and good sealing performance simultaneously.

[0009] Another aspect of the present disclosure provides a multilayer water-soluble film in which the amount of a blocking inhibitor in the first layer of the film (as a percentage of the total weight of the first layer) is greater than the amount of the blocking inhibitor in the second layer of the film (as a percentage of the total weight of the second layer).

[0010] Another aspect of the present disclosure provides a multilayer water-soluble film comprising a first layer containing a bio-based resin and a second layer containing a PVOH homopolymer, a PVOH copolymer, or a blend thereof.

[0011] Another aspect of the present disclosure provides a method for producing a multilayer water-soluble film, such as a two-layer film, by a simultaneous solution co-casting process.

[0012] Regarding the compositions and methods described herein, optional features, including components and their composition ranges but not limited thereto, are contemplated to be selected from the various aspects, embodiments, claims, and examples provided herein. For example, the features of the embodiments and compounding approaches described in Examples 1-7 can be combined with any of the additional features provided in the description and claims herein.

[0013] Further aspects and advantages will be apparent to those skilled in the art from a review of the following detailed description. Although the films and processes of the present disclosure can have various forms in embodiments, the following description includes specific embodiments with the understanding that the present disclosure is illustrative and not intended to limit the invention to the specific embodiments described herein.

[0014] For easier understanding of the present disclosure, eight drawings are attached hereto. The drawings herein are illustrative in nature and not intended to be limiting.

Brief Description of the Drawings

[0015]

Figure 1

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Figure 8A

Figure 8B

Mode for Carrying Out the Invention

[0016] One aspect of the present disclosure provides a water-soluble film including a plurality of layers that are in continuous contact with each other, and the film is prepared by a simultaneous solution co-casting process. The film of this aspect, namely the multilayer water-soluble film, includes a plurality of layers containing a water-soluble resin, and each water-soluble resin independently includes one or more polymers selected from polyvinyl alcohol homopolymers, polyvinyl alcohol copolymers, and combinations thereof. Each layer may further include one or more secondary components as described herein.

[0017] The multilayer water-soluble film of this aspect can include two layers. The first layer can include a first water-soluble resin that can include a polyvinyl alcohol homopolymer, a polyvinyl alcohol copolymer, or a combination thereof, and the second layer can include a second water-soluble resin that can include a polyvinyl alcohol homopolymer, a polyvinyl alcohol copolymer, or a combination thereof. Optionally, the second water-soluble resin can be different from the first water-soluble resin. In other options, the water-soluble film can contain a first layer that includes a water-soluble cellulose, such as hydroxypropyl methylcellulose, and a second layer that includes a polyvinyl alcohol resin that can be a polyvinyl alcohol homopolymer, a polyvinyl alcohol copolymer, or a blend thereof.

[0018] In a film in which the first and / or second water-soluble resin contains a blend of a polyvinyl alcohol homopolymer and a polyvinyl alcohol copolymer, the amounts of the polyvinyl alcohol homopolymer and the polyvinyl alcohol copolymer that constitute the first and / or second water-soluble resin are not particularly limited. Optionally, the first water-soluble resin can contain the polyvinyl alcohol homopolymer in an amount in the range of about 20 wt% to about 70 wt%, or about 25 wt% to about 60 wt%, or about 30 wt% to about 50 wt%, or about 35 wt% to about 45 wt% based on the total weight of the first layer. Optionally, the first water-soluble resin can contain the polyvinyl alcohol copolymer in an amount in the range of about 5 wt% to about 50 wt%, or about 10 wt% to about 40 wt%, or about 15 wt% to about 35 wt%, or about 20 wt% to about 30 wt% based on the total weight of the first layer. Optionally, the second water-soluble resin can contain the polyvinyl alcohol homopolymer in an amount in the range of about 20 wt% to about 70 wt%, or about 25 wt% to about 60 wt%, or about 30 wt% to about 50 wt%, or about 35 wt% to about 45 wt% based on the total weight of the second layer. Optionally, the second water-soluble resin can contain the polyvinyl alcohol copolymer in an amount in the range of about 5 wt% to about 50 wt%, or about 10 wt% to about 40 wt%, or about 15 wt% to about 35 wt%, or about 20 wt% to about 30 wt% based on the total weight of the second layer. Optionally, the amount of the polyvinyl alcohol homopolymer that constitutes the first water-soluble resin is greater than or equal to the amount of the polyvinyl alcohol copolymer that constitutes the first water-soluble resin.

[0019] The multilayer water-soluble film of this aspect can have any suitable thickness. For example, the water-soluble film can have a thickness in the range of about 15 microns to about 150 microns. Each layer constituting the water-soluble film can have any suitable thickness. For example, each layer can independently have a thickness in the range of about 1 micron to about 100 microns. The relative thicknesses of the layers constituting the multilayer film are not particularly limited. For example, the ratio of the thicknesses of the first and second layers of the multilayer film of the present disclosure can be in the range of about 1:200 to about 200:1, or about 1:100 to about 100:1, or about 1:20 to about 20:1, or about 1:5 to about 5:1, or about 1:2 to 2:1, or about 1:1.

[0020] Optionally, the multilayer water-soluble film according to the present disclosure can include one or more water-insoluble layers. The water-insoluble layer can include a backing layer or a release layer in contact with the multilayer water-soluble film, and can facilitate the release of the multilayer water-soluble film, such as when the water-soluble film is wound into a roll. Suitable water-insoluble layers can include polymers including, but not limited to, polyethylene, polypropylene, polyethylene terephthalate, and combinations thereof.

[0021] Another aspect of the present disclosure provides a multilayer water-soluble film in which the amount of one or more blocking agents in the first layer of the film (as a percentage of the total weight of the first layer) is greater than the amount of blocking agent in the second layer of the film (as a percentage of the total weight of the second layer). Optionally, the second layer can be free of, substantially free of, or have a lower concentration of blocking agent compared to the first layer. Optionally, the first layer includes the gloss surface of the film, i.e., the surface that contacts air during drying. The film according to this aspect can be designed to simultaneously exhibit a combination of both a low coefficient of friction and a low haze, e.g., when disposed as the outer surface of a multilayer film, the coefficient of friction corresponding to the layer containing one or more blocking agents and the haze value inherent in the entire thickness of the multilayer film. For example, the film according to this aspect can show that the combination of haze (%) and static coefficient of friction ("COF") is within the polygon defined by the vertices of about (0.03, 13), about (59, 0.5), about (10, 0.1), and about (0.1, 0.1) (haze (%), static COF). FIG. 1 shows a plot of this polygon illustrated as a dotted line and also shows the (haze (%), static COF) points in single-layer and bilayer films according to the examples described herein. Optionally, the film according to this aspect can show that the combination of haze (%) and static coefficient of friction ("COF") is within the polygon defined by the vertices of about (0.03, 10), about (55, 0.5), about (10, 0.1), and about (0.1, 0.1) (haze (%), static COF). FIG. 2 shows a plot of this polygon illustrated as a dotted line and also shows the (haze (%), static COF) points in single-layer and bilayer films according to the examples described herein. One or more blocking agents in the first layer can impart a low coefficient of friction to this layer. However, since the multilayer film of this aspect can contain the blocking agent preferentially, mainly, or only in one layer, the multilayer film can be designed to exhibit a lower haze compared to a film containing the same concentration of blocking agent throughout the cross-section of the film.Accordingly, the film obtains the advantage of the property that the coefficient of friction is essentially characteristic of the outer surface of the film so that the entire thickness of the film does not need to contain an anti-blocking agent in order to give the surface of the film a low coefficient of friction. Accordingly, a multilayer film in this aspect can be designed to exhibit an equivalent coefficient of friction but a reduced haze as compared to a single-layer film having the same concentration of anti-blocking agent. Alternatively, a multilayer film in this aspect can be designed to exhibit an excellent, reduced coefficient of friction and an equivalent haze as compared to a single-layer film containing the same concentration of anti-blocking agent.

[0022] Another aspect of the present disclosure provides a multilayer water-soluble film comprising a first layer containing a blend of a PVOH homopolymer and a PVOH copolymer, and a second layer comprising a PVOH homopolymer or a blend of PVOH homopolymers. The film according to this aspect can provide a high barrier to water vapor as a result of the PVOH copolymer-containing layer, and good sealing performance as a result of the PVOH homopolymer layer, i.e., high seal strength when a first portion of the film is heat-sealed to a second portion of the film or when separate such films are sealed to each other. The first portion and the second portion can be sealed, and the surface of the layer containing the blend of the PVOH homopolymer and the PVOH copolymer is sealed to the surface of the layer containing the PVOH homopolymer or the blend of PVOH homopolymers.

[0023] Another aspect of the present disclosure provides a multilayer water-soluble film comprising a first layer containing a bio-based resin and a second layer containing a PVOH homopolymer, a PVOH copolymer, or a blend thereof.

[0024] Another aspect of the present disclosure provides a multilayer water-soluble film comprising an upper layer including a foamed film.

[0025] The multilayer water-soluble film according to the present disclosure can be free of an intermediate layer such as an adhesive between layers such as between a first layer and a second layer of a two-layer film.

[0026] A water-soluble film having the same composition and thickness as the first layer of the multilayer film of the present disclosure can have a dissolution time of 300 seconds or less, or 200 seconds or less at 20°C based on the MSTM205 test method described herein.

[0027] The multilayer water-soluble film according to the present disclosure can have a second layer including an outer surface, and when the film is sealed to itself by a first portion of the outer surface of the second layer that is sealed to a second portion of the outer surface of the second layer, it can have a watertight strength in the range of about 5 N to about 18 N, or about 10 N to about 18 N, or about 12 N or more based on the seal strength test described herein.

[0028] The multilayer water-soluble film according to the present disclosure can have a second layer including an outer surface, and when the film is sealed to itself by a first portion of the outer surface of the second layer that is sealed to a second portion of the outer surface of the second layer, it can have a watertight strength in the range of about 10 N or more, or about 12 N or more, or about 15 N or more based on the seal strength test described herein, and a water vapor transmission rate of about 100 g / m per 24 hours 2 or less, or about 50 g / m per 24 hours 2 or less, or about 30 g / m per 24 hours 2 or less based on the water vapor transmission rate test method described herein.

[0029] The present disclosure also provides a co-casting process for manufacturing a multilayer water-soluble film, the process comprising simultaneously casting a plurality of resin solutions to form a multilayer solution composition comprising layers of the plurality of resin solutions, and drying the multilayer solution composition to form a multilayer film. The multilayer film manufactured according to the co-casting process of the present disclosure can provide one or more advantageous properties compared to a multilayer film manufactured according to a continuous casting process, the multilayer film being constructed by solution casting a second layer, at least partially drying the second layer by application of heat to form a film, solution casting a first layer in contact with the second film, and drying the layers to form a multilayer film. The co-casting process of the present disclosure can be used to provide a multilayer film in fewer steps than a continuous casting process. Further, advantageously, each layer of the multilayer film manufactured by the co-casting process of the present disclosure will experience the same heating history, whereas each layer of a multilayer film manufactured by a continuous casting process will experience a different heating history due to the plurality of heating and drying steps that make up the continuous casting process, for example, the first casting layer will experience a longer heating and drying time as it experiences additional heating to enable the second casting layer to dry. Without intending to be bound by theory, the simultaneous solution co-casting process according to the present disclosure allows for limited movement of adjacent layers into each other such that adjacent layers are more effectively bonded and the risk of cohesive failure in the multilayer film is minimized.

[0030] A textured film can be manufactured using the simultaneous solution co-casting process of the present disclosure. In particular, inserts into the multi-slot die described herein can be used during simultaneous solution co-casting to create stripes in the top layer of the multilayer film.

[0031] Another aspect of the present disclosure provides a water-soluble unit dose article. The unit dose article can include a pouch having an outer wall, the outer wall having an outer surface and an inner surface defining an inner pouch volume, the outer wall including the multilayer water-soluble film of the present disclosure. Optionally, the inner pouch volume can contain a composition. The multilayer film constituting the unit dose article of this aspect can be selected to provide an article having useful properties derived from the properties of the component film layers. For example, the multilayer film can be designed to include a first layer that provides a high barrier to water vapor transmission and a second layer that exhibits high seal strength when sealed to itself, for example. Such a multilayer film can be useful for constructing a water-soluble unit dose article, for example, by sealing a first portion of the second layer to a second portion of the second layer to form a pouch that can contain a composition. Articles constructed from such multilayer films are also expected to show a low risk of seal failure (i.e., a low risk of early breakage) while preventing moisture from reaching the composition contained therein.

[0032] Another aspect of the present disclosure provides a water-soluble unit dose article including a plurality of compartments, the unit dose article including one or more multilayer films of the present disclosure. The unit dose article can include first and second sealed compartments. The second compartment can be in an overlapping relationship with the first sealed compartment such that the second sealed compartment and the first sealed compartment share an internal partition wall with respect to the pouch. The unit dose article including the first and second sealed compartments can further include a third sealed compartment. The third sealed compartment can be in an overlapping relationship with the first sealed compartment such that the third sealed compartment and the first sealed compartment share an internal partition wall with respect to the pouch. The film of the first compartment can be the multilayer film of the present disclosure. The film of the second compartment can be the multilayer film of the present disclosure. The film of the partition wall can be the multilayer film of the present disclosure. The films of the first and second compartments can be the multilayer films of the present disclosure. The films of the first and second compartments, and the partition wall, can be the multilayer films of the present disclosure.

[0033] A unit dose article comprising a plurality of compartments and including one or more multilayer films of the present disclosure can be made according to a process that includes: (a) forming a first compartment that includes a first film; (b) forming a depression in some or all of the sealed first compartment formed in step (a) to produce a second formed compartment that includes a second film overlying the first compartment; (c) filling and sealing the second compartment with a third film; (d) sealing the first, second, and third films; and (e) cutting the film to produce a multi-compartment pouch. The depression formed in step (b) can be achieved by applying a vacuum to the compartment prepared in step (a). The first water-soluble film can be a multilayer film of the present disclosure. The second water-soluble film can be a multilayer film of the present disclosure. The third water-soluble film can be a multilayer film of the present disclosure. The first and second water-soluble films can be multilayer films of the present disclosure. The first and third water-soluble films can be multilayer films of the present disclosure. The first, second, and third water-soluble films can be multilayer films of the present disclosure.

[0034] The different compartments of a multi-compartment article that includes one or more multilayer films of the present disclosure can be made together in a side-by-side fashion or in a concentric fashion, and the resulting joined pouch can be separated by cutting or cannot be separated. Alternatively, the compartments can be made separately.

[0035] Another method of manufacturing a unit-dose article comprising a plurality of compartments, wherein the unit-dose article comprises one or more multilayer films of the present disclosure, comprises: (a) deforming a first water-soluble film in a mold to create an open cavity; (b) filling the open cavity formed by the first water-soluble film with a composition; (c) separately, deforming a third water-soluble film in a mold to create at least one open cavity; (d) filling at least one open cavity in the third film with a composition (e.g., the same as or different from the composition of step (b)); (e) closing one or more of the open-filled cavities of step (d) with a second water-soluble film; (f) optionally sealing the second water-soluble film and the third water-soluble film via a solvent seal to create a closed intermediate; (g) closing the open-filled cavity of step (b) with the closed intermediate of step (f); (h) optionally sealing the first water-soluble film and the second water-soluble film of the closed intermediate of step (g) via a solvent seal to create a water-soluble unit-dose article. The use of this method can provide, for example, a unit-dose article having compartments of overlaid compositions, e.g., one or more compartments overlaid relative to another compartment. Any one of the sealing steps can include a solvent seal, and at least one of the sealing steps can include a solvent seal. Each of the first and second water-soluble films has a first side and a second side, and the first side of the first water-soluble film can be sealed to the second side of the second water-soluble film to create a first compartment between the first water-soluble film and the second water-soluble film, and the first side of the second water-soluble film can be sealed to the second side of the third water-soluble film to create at least a second compartment between the second water-soluble film and the third water-soluble film, and the second compartment can be disposed over the first compartment. The first water-soluble film and the third water-soluble film can be the same, i.e., physically and chemically the same, prior to thermoforming, and the term "the same" means within the standard processes for making specification changes.Optionally, the sealing of the first water-soluble film and the second water-soluble film can include the step of wetting the second water-soluble film with the sealing solution described herein, for example, via a contact wetting method. Additionally, or alternatively, the sealing of the second water-soluble film and the third water-soluble film can optionally include the step of wetting the second water-soluble film with the sealing solution described herein, for example, via a contact wetting method. The first water-soluble film can be a multilayer film of the present disclosure. The second water-soluble film can be a multilayer film of the present disclosure. The third water-soluble film can be a multilayer film of the present disclosure. The first and second water-soluble films can be multilayer films of the present disclosure. The first and third water-soluble films can be multilayer films of the present disclosure. The first, second, and third water-soluble films can be multilayer films of the present disclosure.

[0036] A water-soluble unit-dose article comprising a plurality of compartments can optionally contain a fabric and a home care composition in one or more compartments, including those having an overlaid configuration. The fabric and home care composition includes fabric treatment, treatment of hard and any other surfaces in the area of fabric and home care, air care, car care, dishwashing, fabric conditioning and softening, laundry detergents, additives and / or care for washing and rinsing, hard surface cleaning and / or treatment, and other cleaning for consumer or business use.

[0037] Fabric and home care products are optionally used or consumed in the form in which they are sold and are for treating fabrics, hard surfaces, and any other surfaces in the area of fabric and home care, including air care, car care, dishwashing, fabric conditioning (including softening and / or freshening), laundry detergents, additives and / or care for washing and rinsing, hard surface cleaning and / or treatment including floor and toilet cleaners, and other cleaning for fabric or home use, including deodorants and fragrance delivery systems.

[0038] Examples of cleaning and / or treatment compositions include, but are not limited to, products for treating fabrics, hard surfaces, and any other surfaces in the areas of fabrics and home care, including air care, car care, dishwashing, fabric conditioning (including softening and / or freshening), laundry detergents, laundry and rinse additives and / or care, hard surface cleaning and / or treatment including floor and toilet cleaners, all-purpose or "heavy-duty" cleaners in granular or powder form, especially cleaning detergents; all-purpose cleaners in liquid, gel, or paste form, especially the so-called heavy liquid type; liquid fabric softeners; hand dishwashing detergents or light dishwashing detergents, especially the high-foaming type; machine dishwashing detergents including various tablet, granular, liquid, and rinse aid types for household and commercial use; bathroom cleaners including car or carpet shampoos, toilet cleaners; and cleaning aids such as bleach additives and "stain sticks" or pretreatment types, substrate-mounted products such as dryer sheets.

[0039] Fabric and / or hard surface cleaning and / or treatment compositions include, unless otherwise indicated, all-purpose or "heavy-duty" cleaners in granular or powder form, especially cleaning detergents; all-purpose cleaners in liquid, gel, or paste form, especially the so-called heavy liquid type; liquid fabric softeners; hand dishwashing detergents or light dishwashing detergents, especially the high-foaming type; machine dishwashing detergents including various tablet, granular, liquid, and rinse aid types for household and commercial use; liquid cleaners and disinfectants, bathroom cleaners including car or carpet shampoos, toilet cleaners; fabric conditioning products including softening and / or deodorizing which may be in liquid, solid, and / or dryer sheet form; cleaning aids such as bleach additives and "stain sticks" or pretreatment types, substrate-mounted products such as dryer sheets. All such products, to the extent applicable, may be in standard, concentrated, or even highly concentrated form, even where such products may be non-aqueous in certain embodiments.

[0040] Optionally, the multilayer water-soluble film according to the present disclosure can include one or more active ingredients. The one or more active ingredients can be present throughout the film or in one or more of its layers, deposited on one or both surfaces of the film, or both. Suitable active ingredients include, but are not limited to, detergents, cleaning agents, superabsorbents, water softeners, stain removers, fabric softeners, color protectants, enzymes, fragrances, odor removers, abrasives, disinfectants, peroxides, and other bleaching agents including, but not limited to, hypochlorous acid, hydroxides, chloramines, chloramides, and chlorimides, as well as personal care / hygiene products including, but not limited to, shampoos, skin cleansers, exfoliants, and tooth cleansers. Suitable active ingredients can also include components that can inhibit or suppress crosslinking, such as, for example, sodium acetate.

[0041] The multilayer water-soluble films according to the present disclosure can be designed to reduce or eliminate harmful interactions between unit-dose articles such as pouches and the contents of the articles. The multilayer water-soluble films according to the present disclosure can be prepared such that one layer of the film is enriched in components as compared to one or more other layers of the film. A unit-dose article containing one or more compartments can be constructed from such a film such that the inner surface of the compartment of the unit-dose article, i.e., the surface disposed adjacent to or in direct contact with the contents of the compartment, comprises a film layer enriched in components. For example, one layer of the film can be enriched in one or more of low molecular weight polyols such as glycerin, diglycerin, sorbitol, ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tetraethylene glycol, propylene glycol, polyethylene glycol up to 400 MW, neopentyl glycol, trimethylolpropane, polyether polyol, sorbitol, methylpropanediol, 2-methyl-1,3-propanediol (MPDiol®), or combinations thereof to construct a multilayer water-soluble film. The unit-dose article can be constructed from such a film such that the film layer enriched in the low molecular weight polyol forms the inner surface of one or more compartments of the unit-dose article. In such a configuration, the polyol at the inner film surface can be utilized, for example, to crosslink with materials in the pouch contents such as, but not limited to, aldehydes (e.g., glutaraldehyde), acids and polyacids (e.g., citric acid), or sodium borate. Such crosslinking can advantageously improve the rigidity of the packaging film. This use of the low molecular weight polyol can be considered a sacrificial use, for example, whereby the polyol is for crosslinking rather than its typical use for plasticization of the film layer. Such crosslinking can also reduce the undesirable chain scission of the polymer film that can occur in films used for packaging oxygenated bleaching agents.

[0042] All percentages, parts, and ratios referred to in this specification are based on the total dry weight of the film composition of the present disclosure or the total weight of the packet contents composition when instances may exist, and unless otherwise specified, all measurements are made at about 25°C. All such weights related to the listed components are based on the active level and thus, unless otherwise specified, do not include carriers or by-products that may be included in commercially available materials.

[0043] All ranges set forth herein include all possible subset ranges and any combination of such subset ranges. By default, ranges include the recited endpoints unless otherwise stated. Where a range of values is provided, each value between the upper and lower limits of that range, and any other recited value or values within that recited range, are understood to be included within the present disclosure. The upper and lower limits of these smaller ranges may independently be included within the smaller ranges and are also included within the present disclosure and subject to any specifically excluded limits within the recited range. Where the recited range includes one or both of these limiting values, ranges excluding either or both of these included limiting values are also contemplated as part of the present disclosure.

[0044] For any numerical value recited herein, for example, as part of a parameter of the recited object or a range associated with the recited object, another alternative that forms part of the recitation is clearly contemplated to be a functionally equivalent range around the specific numerical value (e.g., for a dimension disclosed as "40 mm", an alternative contemplated embodiment is "about 40 mm").

[0045] As used herein, the terms "packet" and "pouch" should be considered interchangeable. The terms "packet" and "pouch" can each be used to refer to a container made using a film and, preferably, a completely sealed container having a material sealed therein, for example, in the form of a metered dose delivery system. The sealed pouch can be made from any suitable method including such processes and features as heat sealing, solvent adhesion, and adhesive sealing (e.g., using the use of a water-soluble adhesive).

[0046] As used herein, unless otherwise specified, the terms "weight % (wt.%)" and "weight % (wt%)" refer to the composition of a particular element in terms of the weight of the "dry" (anhydrous) film, including the residual moisture in the film (when the film is described and applicable) or the component by the total weight of the composition or coating, when the case may depend on the context.

[0047] As used herein, unless otherwise specified, the term "PHR" ("phr") is intended to refer to the composition of a particular element in parts per 100 parts of a water-soluble film or a water-soluble polymer resin in a solution used to make the film (regardless of PVOH or other polymer resin unless otherwise specified).

[0048] Methods of forming a container from a film are known in the art. The film can be used to form a container (pouch) by any suitable process including vertical form fill seal (VFFS) or thermoforming. The film can be sealed by any suitable process including, for example, solvent sealing or heat sealing of the film layer around the perimeter of the container. The pouch can be used, for example, for input materials delivered to bulk water.

[0049] Unless otherwise described, the films, pouches, and related methods of use are intended to include embodiments that include any combination of one or more of the additional optional elements, features, and steps described further below.

[0050] The water-soluble pouch can contain (enclose) a composition. The composition can be selected from liquids, solids, or combinations thereof. As used herein, "liquid" includes free-flowing liquids as well as pastes, gels, foams, and mousses. Gases, such as suspended bubbles, or solids, such as particles, can be included within the liquid. "Solid" as used herein includes, but is not limited to, powders, aggregates, and mixtures thereof. Non-limiting examples of solids include granules, microcapsules, beads, noodles, and pearlised balls.

[0051] For each layer of the multilayer film of the present disclosure, the water-soluble resin constituting the layer can include one or more polyvinyl alcohol (PVOH) homopolymers, one or more polyvinyl alcohol copolymers, or combinations thereof. As used herein, the term "homopolymer" generally includes a polymer having a single type of monomer repeating unit (e.g., a polymer chain consisting of or essentially consisting of a single monomer repeating unit). In the specific case of PVOH, the term "homopolymer" (or "PVOH homopolymer") can include a copolymer consisting of the distribution of vinyl alcohol monomer units and vinyl acetate monomer units depending on the degree of hydrolysis (e.g., a polymer chain consisting of or essentially consisting of vinyl alcohol and vinyl acetate monomer units). In the limiting case of 100% hydrolysis, the PVOH homopolymer can include a true homopolymer having only vinyl alcohol units.

[0052] For each layer of the multilayer film of the present disclosure, the water-soluble resin constituting the layer can contain one or more bio-based resins. Suitable bio-based resins include, but are not limited to, cellulose ethers, cellulose esters, cellulose amides, gelatin, methylcellulose, carboxymethylcellulose and its salts, dextrin, ethylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, maltodextrin, starch, modified starch, guar gum, acacia gum, gum arabic, xanthan gum, pullulan, carrageenan, ι-carrageenan, κ-carrageenan, pea protein, chitosan, chitosan derivatives, alginate and its salts, and combinations of one or more of the above. Bio-based resins particularly suitable for incorporation into the multilayer film according to the present disclosure are cellulose polymers and modified celluloses, including, but not limited to, hydroxypropylmethylcellulose, hydroxyethylcellulose, ethylcellulose, methylcellulose, carboxymethylcellulose and its salts, and combinations thereof. Suitable bio-based resins can also include synthetic polymers derived from bio-based monomers such as polylactic acid and polyethylene derived from bio-origin ethylene. The bio-based resin can be selected from water-soluble type resins.

[0053] Optionally, the multilayer film can include a first layer containing a first polyvinyl alcohol resin containing a polyvinyl alcohol homopolymer, a polyvinyl alcohol copolymer, or a combination thereof, and at least a second layer containing a second polyvinyl alcohol resin containing a polyvinyl alcohol homopolymer, a polyvinyl alcohol copolymer, or a combination thereof, wherein the second polyvinyl alcohol resin is different from the first polyvinyl alcohol resin.

[0054] Polyvinyl alcohol is a synthetic resin generally prepared by hydrolysis or alcoholysis, commonly referred to as saponification, of polyvinyl acetate. Fully hydrolyzed PVOH, in which substantially all acetate groups have been converted to alcohol groups, is a highly hydrogen-bonded, highly crystalline polymer that dissolves only in hot water, i.e., water above about 140°F (about 60°C). If a sufficient number of acetate groups remain after hydrolysis of polyvinyl acetate, i.e., if the PVOH homopolymer is partially hydrolyzed, the polymer is more weakly hydrogen-bonded, less crystalline, and generally soluble in cold water, i.e., water below about 50°F (about 10°C). Therefore, a partially hydrolyzed polymer is a vinyl alcohol-vinyl acetate copolymer but is generally referred to as a PVOH homopolymer.

[0055] The viscosity (μ) of a PVOH homopolymer or copolymer is determined by measuring a freshly prepared PVOH solution using a Brookfield LV viscometer equipped with a UL adapter, as described in the British Standard EN ISO 15023-2:2006 Annex E Brookfield test method. It is an international practice to describe the viscosity of a 4% aqueous polyvinyl alcohol solution at 20°C. Unless otherwise specified, all viscosities specified in this disclosure in centipoises (cPs) should be understood to refer to the viscosity of a 4% aqueous polyvinyl alcohol solution at 20°C. Similarly, when a resin is described as having (or not having) a particular viscosity, unless otherwise specified, it is intended that the specified viscosity be the average viscosity of a resin that can essentially have the corresponding molecular weight distribution.

[0056] The viscosity of PVOH is related to the weight-average molecular weight of the PVOH resin

Number

[0057] The first water-soluble resin and the second water-soluble resin can each have a weight average molecular weight, and the weight average molecular weight of the first water-soluble resin can be greater than the weight average molecular weight of the second water-soluble resin. Alternatively, the first water-soluble resin and the second water-soluble resin can each have a number average molecular weight, and the number average molecular weight of the first water-soluble resin can be greater than the number average molecular weight of the second water-soluble resin.

[0058] As used herein, the degree of hydrolysis of a polyvinyl alcohol homopolymer or copolymer is expressed as the mole percentage of vinyl acetate units converted to vinyl alcohol units. The polyvinyl alcohol homopolymer or copolymer constituting the first or second water-soluble resin can independently have a degree of hydrolysis of at least about 70%, 80%, 84%, or 85%, and up to about 99% or 99.9%, for example, in the range of about 70% to about 99.9%, about 75% to about 95%, about 85% to about 88%, about 88%, about 88% to about 90%, about 84% to about 89%, about 85% to about 99.7%, about 85% to about 95%, about 87% to about 98%, about 89% to about 99%, or about 90% to about 99%, for example, about 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% (DH). The degree of hydrolysis is specifically a measure of the amount of acetic acid removed from the polyvinyl acetate polymer (e.g., via hydrolysis or saponification), but it is most commonly used to understand the amount of acetic acid remaining in the PVOH polymer or copolymer. The acetate groups form the amorphous or non-crystalline regions of the PVOH copolymer. Thus, it can be stated as an approximation that the higher the DH, the relatively higher the crystallinity of the PVOH copolymer or blend of PVOH copolymers. When a PVOH resin is described as having (or not having) a specific DH, unless otherwise specified, the designated DH is intended to be the average DH in the PVOH resin.

[0059] The first water-soluble resin and the second water-soluble resin can independently include a PVOH homopolymer, a PVOH copolymer, or a blend thereof, and the first water-soluble resin can have a degree of hydrolysis greater than or equal to that of the second water-soluble resin.

[0060] The water-soluble resin constituting any layer of the multilayer film of the present disclosure can include an anion-modified polyvinyl alcohol, i.e., a PVOH copolymer that can be a partially or fully hydrolyzed PVOH copolymer containing an anionic monomer unit. The anion-modified polyvinyl alcohol can be a PVOH terpolymer containing vinyl alcohol monomer units, vinyl acetate monomer units (i.e., when not fully hydrolyzed), and a single type of anionic monomer unit (e.g., when a single type of monomer unit can include the equivalent acid form, salt form, and optionally ester form of the anionic monomer unit). Optionally, the first water-soluble resin can include an anion-modified polyvinyl alcohol. Optionally, the second water-soluble resin can include an anion-modified polyvinyl alcohol. General classes of anionic monomer units that can be used in PVOH copolymers include vinyl monocarboxylic acid monomers, their esters, and anhydrides, dicarboxylic acid monomers having polymerizable double bonds, their esters, and anhydrides, and vinyl polymerization units corresponding to the alkali metal salts of any of the foregoing. Examples of suitable anionic monomer units include vinyl acetate, maleic acid, monoalkyl maleate, dialkyl maleate, maleic anhydride, fumaric acid, monoalkyl fumarate, dialkyl fumarate, itaconic acid, monoalkyl itaconate, dialkyl itaconate, itaconic anhydride, citraconic acid, monoalkyl citraconate, dialkyl citraconate, citraconic anhydride, mesaconic acid, monoalkyl mesaconate, dialkyl mesaconate, glutaconic acid, monoalkyl glutaconate, dialkyl glutaconate, glutaconic anhydride, alkyl acrylate, methyl acrylate, vinyl sulfonic acid, the alkali metal salts of the foregoing, the esters of the foregoing, and combinations of the foregoing, including, but not limited to, vinyl polymerization units resulting from vinyl anionic monomers.The anionic monomer unit can be derived from a monomer selected from the group consisting of vinyl acetic acid, alkyl acrylate, maleic acid, monoalkyl maleate, dialkyl maleate, monomethyl maleate, dimethyl maleate, maleic anhydride, fumaric acid, monoalkyl fumarate, dialkyl fumarate, monomethyl fumarate, dimethyl fumarate, itaconic acid, monomethyl itaconate, dimethyl itaconate, itaconic anhydride, citraconic acid, monoalkyl citraconate, dialkyl citraconate, citraconic anhydride, mesaconic acid, monoalkyl mesaconate, dialkyl mesaconate, glutaconic acid, monoalkyl glutaconate, dialkyl glutaconate, glutaconic anhydride, vinyl sulfonic acid, alkyl sulfonic acid, ethylene sulfonic acid, 2-acrylamido-1-methylpropane sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid (AMPS), 2-methylacrylamido-2-methylpropane sulfonic acid, 2-sulfoethyl acrylate, hydrolyzed N-vinylpyrrolidone, the aforementioned alkali metal salts, the aforementioned esters, and the aforementioned combinations (e.g., multiple types of anionic monomer units, or equivalent forms of the same anionic monomer unit).

[0061] When the water-soluble resin contains a PVOH copolymer, the degree of modification of the PVOH copolymer is not particularly limited. For example, the PVOH copolymer can have a degree of modification in the range of about 0.5 mol.% to about 10 mol.%, or about 1 mol.% to about 10 mol.%, about 1 mol.% to about 8 mol.%, about 1 mol% to about 5 mol.%, about 2 mol.% to about 6 mol.%, about 3 mol.% to about 5 mol.%, or about 1 mol.% to about 3 mol.% (e.g., at least about 1.0, 1.5, 1.8, 2.0, 2.5, 3.0, 3.5, or 4.0 mol.% and at most about 3.0, 4.0, 4.5, 5.0, 6.0, 8.0, or 10 mol.%).

[0062] PVOH copolymers having pendant carboxyl groups, such as maleic acid-modified PVOH, can form lactone rings between adjacent pendant carboxyl groups and alcohol groups, and thus it is understood in the art that the water solubility of PVOH copolymer resins is reduced. In the presence of strong bases, the lactone rings can be opened over a period of several weeks under relatively warm (ambient), high humidity conditions (e.g., via a lactone ring-opening reaction that forms the corresponding pendant carboxyl groups and alcohol groups with increased water solubility). Therefore, such PVOH copolymer films can be thought to become more soluble due to chemical interactions between the film and the alkaline composition inside the pouch during storage. Maleic acid-modified PVOH can substantially contain no lactone rings such that the modified PVOH has about 2 pendant carboxylate groups per maleic acid monomer unit. Maleic acid-modified PVOH can contain from about 1.5 pendant carboxylate groups to 2 pendant carboxylate groups per maleic acid monomer unit, or from about 1.2 pendant carboxylate groups to about 2 pendant carboxylate groups per maleic acid monomer unit, or from about 1 pendant carboxylate group to about 2 pendant carboxylate groups per maleic acid monomer unit, for example, about 2 pendant carboxylate groups per maleic acid monomer unit, or about 1.9 pendant carboxylate groups per maleic acid monomer unit, or about 1.8 pendant carboxylate groups per maleic acid monomer unit, or about 1.7 pendant carboxylate groups per maleic acid monomer unit, or about 1.6 pendant carboxylate groups per maleic acid monomer unit, or about 1.5 pendant carboxylate groups per maleic acid monomer unit, or about 1.2 pendant carboxylate groups per maleic acid monomer unit, or about 1 pendant carboxylate group per maleic acid monomer unit, etc.

[0063] Each layer of the multilayer film of the present disclosure can further include one or more water-soluble polymers including, but not limited to, polyvinyl alcohol, water-soluble acrylate copolymer, polyethyleneimine, pullulan, water-soluble natural polymers including, but not limited to, guar gum, acacia gum, xanthan gum, carrageenan, and starch, water-soluble polymer-modified starch, the aforementioned copolymers, or any combination of the foregoing. Further other water-soluble polymers include, but are not limited to, polyalkylene oxide, polyacrylamide, cellulose, cellulose ether, cellulose ester, cellulose amide, polyvinyl acetate, polycarboxylic acid and its salts, polyamino acid, polyamide, gelatin, methyl cellulose, carboxymethyl cellulose and its salts, dextrin, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, maltodextrin, polymethacrylate, or any combination of the foregoing. Such water-soluble polymers are commercially available from various sources.

[0064] For each layer of the multilayer film, the water-soluble resin constituting the layer can further include a second PVOH resin. The second PVOH resin can include a PVOH homopolymer, a PVOH copolymer, or a combination thereof. The second PVOH can include a PVOH copolymer containing the anionic monomer units described above. The second PVOH can include an anionic monomer unit selected from the group consisting of AMPS, hydrolyzed N-vinylpyrrolidone (NVP), maleic anhydride, monomethyl maleate, their alkali salts, and combinations thereof. The second PVOH can include an anionic monomer unit selected from the group consisting of monomethyl maleate, maleic anhydride, their alkali salts, and combinations thereof.

[0065] Each layer of the multilayer film can optionally contain, in addition to the water-soluble resin, one or more additional agents including, but not limited to, plasticizers, surfactants, lubricants, release agents, fillers, extenders, cross-linking agents, barrier agents, anti-blocking agents, defoaming agents, nanoparticles such as layered silicate-type nanoclays, bleaching agents, antioxidants, aversion agents such as bittering agents, stimulants, other functional components, and combinations of the foregoing, in amounts suitable for their intended purposes.

[0066] Each layer of the multilayer film can independently contain any suitable plasticizer. A plasticizer is a liquid, solid, or semi-solid added to a material (usually a resin or elastomer) to make the material more flexible, more pliable (by lowering the glass transition temperature of the polymer), or easier to process. Additionally, or alternatively, the polymer can be internally plasticized by chemically modifying the polymer or monomer. The water-soluble films described herein can contain one or more plasticizers. Examples of plasticizers include glycerol, diglycerol, sorbitol, ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tetraethylene glycol, propylene glycol, polypropylene glycol, polyethylene glycol with a molecular weight of up to 400 Da, hexylene glycol, neopentyl glycol, trimethylolpropane, polyether polyol, polyether diol, polyether triol, xylitol, 2-methyl-1,3-propanediol (MPDiol®), ethanolamine, glycerol propylene oxide polymer (such as Voranol™ available from The Dow Chemical Company), or mixtures thereof. Lower levels (e.g., 1 wt% to 10 wt%) of low molecular weight polar plasticizers such as glycerol and / or trimethylolpropane can be included as a means of maintaining flexibility and the ability to be converted into articles using standard equipment.

[0067] When the layer of the multilayer film contains a plasticizer, the plasticizer can be provided in the range of about 1 wt% to about 45 wt%, or about 5 wt% to about 35 wt%, or about 7.5 wt% to about 30 wt%, or about 8 wt% to about 20 wt%, or about 8 wt% to about 12 wt% based on the total weight of the water-soluble resin in the layer. For example, it can be provided at about 1 wt%, 5 wt%, 7.5 wt%, 9 wt%, 10 wt%, 15 wt%, 17.5 wt%, or 25 wt%. The amount of the plasticizer can also be characterized in phr, and each layer can contain the plasticizer in an amount of about 2 to about 75 phr, about 3 to about 60 phr, about 3 to about 50 phr, about 4 to about 40 phr, or about 2 to about 20 phr.

[0068] Without wishing to be bound by theory, it is believed that the plasticizer can be selected to balance maintaining the flexible film and the movement of the active chemical to the film matrix. Further, without wishing to be bound by theory, it is believed that as the plasticization of the film increases, the ability of the active chemical to move into the film increases. Without wishing to be bound by theory, it is believed that the closer the glass transition temperature of the film is to the lower end of the operating temperature range, the higher the resistance of the film to the movement of the chemical into the film. Thus, the type and amount of the plasticizer can be selected to provide a film having a glass transition temperature close to the lower end of the operating temperature range. As used herein, "operating temperature range" refers to the temperature to which the film is exposed during the life cycle of the film, e.g., during storage of the film and use of the film by the consumer. Generally, the operating temperature range is not limited and can generally be in the range of about 0 °C to about 40 °C, or from about 5 - 10 °C to about 38 - 40 °C.

[0069] Each layer can optionally contain other adjuvants and treatment agents in amounts suitable for their intended purposes, including surfactants, lubricants, release agents, fillers, extenders, cross-linking agents, blocking agents, anti-adhesion agents, defoaming agents (foam suppressants), nano-particles such as layered silicate-type nanoclays (e.g., sodium montmorillonite), bleaching agents (e.g., sodium metabisulfite, sodium bisulfite (SBS), or others), bittering agents (e.g., sodium salts of denatonium benzoate, denatonium saccharide, and sodium chloride; sucrose octaacetate; quinine; flavonoids such as quercetin and naringenin; and quassinoids such as quassin and brucine) and aversion agents such as pungent agents (e.g., capsaicin, piperine, allyl isothiocyanate, and resiniferatoxin), and other functional components, but are not limited thereto. For example, each layer may contain a filler, a surfactant, a blocking agent, or a combination of the foregoing.

[0070] Surfactants for use in water-soluble films are well known in the art. Optionally, the surfactant is included to assist in the dispersion of the resin solution during casting. Suitable surfactants can include nonionic, cationic, anionic, and zwitterionic surfactants. Suitable surfactants for each layer of the multilayer film include, but are not limited to, polyoxyethylenated polyoxypropylene glycol, alcohol ethoxylate, alkylphenol ethoxylate, tertiary acetylenic glycol, alkanolamide, polyoxyethylenated amine, quaternary ammonium salt quaternized polyoxyethylenated amine, amine oxide, N-alkyl betaine, and sulfobetaine. Suitable surfactants for each layer of the multilayer film also include, but are not limited to, dialkyl sulfosuccinate, lactylated fatty acid esters of glycerol and propylene glycol, lactyl esters of fatty acids, sodium alkyl sulfate, polysorbate 20, polysorbate 60, polysorbate 65, polysorbate 80, alkyl polyethylene glycol ether, lecithin, acetylated fatty acid esters of glycerol and propylene glycol, sodium lauryl sulfate, acetylated esters of fatty acids, myristyl dimethylamine oxide, trimethyltallow alkyl ammonium chloride, quaternary ammonium compounds, their salts, and combinations of any of the foregoing. Too little surfactant can result in a film having pores, while too much surfactant can result in a film that is slippery or has an oily feel from the excess surfactant present on the surface of the film. Thus, the surfactant can optionally be included in the water-soluble film in an amount, for example, of less than about 2 phr, for example, less than about 1 phr, or less than about 0.8 phr.

[0071] One type of secondary component contemplated for use is an antifoaming agent. The antifoaming agent can assist in the coalescence of bubbles. Suitable antifoaming agents for use in the layers of the multilayer films according to the present disclosure include, but are not limited to, hydrophobic silica, such as Foam Blast® 327, Foam Blast® UVD, Foam Blast® 163, Foam Blast® 269, Foam Blast® 338, Foam Blast® 290, Foam Blast® 332, Foam Blast® 349, Foam Blast® 550, and Foam Blast® 339, which are exclusive non-mineral oil antifoaming agents, fine particle size silicon dioxide or fumed silica, including Foam Blast® antifoaming agents available from Emerald Performance Materials. For example, the layers of the multilayer films disclosed herein include Foam Blast® 338. Optionally, the antifoaming agent can be used in an amount of 0.5 phr or less, or 0.5 phr to 0.01 phr, such as 0.3 phr, 0.2 phr, 0.1 phr, 0.05 phr, 0.04 phr, 0.03 phr, 0.02 phr, or 0.01 phr.

[0072] Suitable fillers, extenders, and antiblocking agents include, but are not limited to, starch, modified starch, crosslinked polyvinylpyrrolidone, crosslinked cellulose, microcrystalline cellulose, silica, metal oxides, calcium carbonate, talc, mica, stearic acid and its metal salts, such as magnesium stearate. Preferred materials are starch, modified starch, and silica, such as high amylose starch, amorphous silica, hydroxyethylated starch, or combinations thereof.

[0073] The aversion agent can be incorporated into each layer of the multilayer film or applied as a coating to the multilayer film. The aversion agent is added in an amount that causes an aversive response such as bitterness, diluted from its commercial form, or otherwise mixed with other water-soluble film components or mixed with a solvent to facilitate application as a coating to the water-soluble film. Such a solvent can be selected from water, low molecular weight alcohols (such as methanol, ethanol, etc.), or plasticizers disclosed herein.

[0074] The blocking inhibitor (e.g., silica and / or stearic acid) can optionally be present in any layer of the multilayer film of the present disclosure in an amount of at least 0.1 phr, or at least 0.5 phr, or at least 1 phr, or about 0.1 - 8.0 phr, or about 0.1 - about 5.0 phr, or about 0.4 - 3.0 phr, or about 0.5 - about 2.0 phr, or about 0.5 - about 1.5 phr, or 0.1 - 1.2 phr, or 0.1 - 2.7 phr, for example, 2.0 phr, 2.8 phr, 3.6 phr, 5.0 phr, or 7.2 phr. The amount of the blocking inhibitor in any layer of the multilayer film of the present disclosure can also be expressed as a percentage of the total weight of the layer. The first layer of the multilayer water-soluble film according to the present disclosure can contain the blocking inhibitor in an amount in the range of about 2% - about 10%, or about 3% - about 8%, or about 3.5% - about 6.5%, or about 4% - about 6% based on the total weight of the first layer. Optionally, the second layer of the film according to the present disclosure can be substantially free of or contain no blocking inhibitor.

[0075] Suitable median particle sizes of the blocking inhibitor include a median size in the range of about 3 or about 4 microns to about 11 microns, or about 4 - about 8 microns, or about 5 - about 6 microns, for example, 5, 6, 7, or 8 microns. Suitable silica is untreated synthetic amorphous silica designed for use in aqueous systems.

[0076] The multilayer film described in this specification can have any suitable thickness. For example, the multilayer film can have a thickness in the range of about 15 micrometers (μm) to about 150 μm, or about 25 μm to about 100 μm, or about 30 μm to about 70 μm, or about 40 μm to about 60 μm. For example, the water-soluble film can have a thickness of about 40 μm, 45 μm, 50 μm, 51 μm, 60 μm, 76 μm, or 88 μm. The multilayer film can have a thickness in the range of about 25 μm to about 100 μm, or about 40 μm to about 100 μm, or about 30 μm to about 70 μm. Further, each layer of the multilayer film can have any suitable thickness. For example, each layer of the water-soluble film can have a thickness in the range of about 1 micron to about 100 microns, or about 5 μm to about 90 μm, or about 10 μm to about 80 μm, or about 20 μm to about 70 μm, or about 30 μm to about 50 μm, for example, a thickness of about 1 μm, 2 μm, 3 μm, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 45 μm, 50 μm, 51 μm, 60 μm, 76 μm, or 88 μm. The first layer can have a thickness in the range of about 1 μm to about 5 μm, and the second layer can have a thickness in the range of about 40 μm to about 75 μm. The relative thicknesses of the layers constituting the multilayer film are not particularly limited. For example, the ratio of the thicknesses of the first and second layers of the multilayer film of the present disclosure can be in the range of about 1:200 to about 200:1, or about 1:100 to 100:1, or about 1:20 to about 20:1, or about 1:5 to about 5:1, or about 1:2 to 2:1, or about 1:1.

[0077] The multilayer film produced by the simultaneous solution co-casting process according to the present disclosure can include a layer of a foamed film, i.e., a layer of a film containing a plurality of macroscopic and / or microscopic voids. The top layer of the simultaneously co-cast multilayer film can be a foamed film layer. The simultaneously co-cast multilayer film can be a bilayer film having an upper layer containing a foamed film. The foamed film layer is produced by casting a layer of a foamed resin solution (i.e., a resin solution into which air or another gas has been incorporated) and drying the foamed resin solution layer, and can provide a film layer containing a plurality of macroscopic and / or microscopic voids. The foamed resin solution can be formed by thoroughly mixing the resin solution to incorporate air. Alternatively, the foamed resin solution can be formed by in-line mixing during the simultaneous solution co-casting process. For example, the resin solution can be mixed in an in-line mixing device disposed downstream of the holding tank containing the resin solution and upstream of the casting surface on which the resin solution layer is cast such that air or another gas is incorporated into the resin solution as the solution is being supplied to the casting surface. Optionally, the in-line mixing can also include mixing the resin solution with a separate gas supply to incorporate gas into the resin solution.

[0078] The multilayer film can include a layer containing a foamed film. The foamed layer can be cast onto a pre-formed film made by any process, which can be referred to as overcasting. The foamed layer can be cast onto the film immediately after formation in the same process, which can be referred to as continuous casting. The top layer of the multilayer film can be a foamed film layer. The continuously cast multilayer film can be a double-layer film having an upper layer containing a foamed film layer, i.e., a foamed film layer cast onto a lower base layer. The continuous casting process for forming a double-layer film having a layer of foamed film can include, by any suitable means, casting a layer of a second resin solution onto a casting surface to form a second (bottom) resin solution layer, at least partially drying the second resin solution layer, directly casting a first (upper) resin solution onto the at least partially dried second resin solution layer, where the first resin solution is a foamed resin solution, and drying the resulting multilayer composition to form a multilayer film. The resin solution can be cast according to solution casting methods known in the art. The lower base layer can be a film made by any process, such as a cast film or a blown film. The second resin solution can be cast using a die such as a slot die, and the first resin solution can be cast using any suitable process, such as a doctor blade device, or can be cast.

[0079] The upper and bottom layers of the two-layer film including the upper layer which is a foamed film layer can independently comprise a PVOH homopolymer, a PVOH copolymer, or a blend thereof. Optionally, the foamed film layer can comprise an anion-modified PVOH copolymer. Optionally, the bottom layer can comprise an anion-modified PVOH copolymer. Optionally, both the foamed film layer and the bottom layer can comprise an anion-modified PVOH copolymer, and the foamed film layer and the bottom layer can optionally comprise the same anion-modified PVOH copolymer.

[0080] Casting a layer of a foaming resin solution, i.e., a resin solution into which air or another gas has been incorporated, can provide a foamed film layer containing macroscopic and / or microscopic voids after drying. The foamed film layer is characterized by a co-gas fraction, i.e., a percent increase in volume of the foamed film layer, compared to the volume of the same film prepared from the same amount of the same resin solution that has not been foamed, i.e., not sufficiently mixed to incorporate air or another gas. The foamed film layer of the water-soluble film according to the present disclosure can have a co-gas fraction of at least about 5% by volume, or at least about 10% by volume, or at least about 20% by volume, or at least about 30% by volume based on the volume of the second layer.

[0081] The water-soluble film according to the present disclosure can include a first layer comprising a methacrylate-modified PVOH copolymer, a plasticizer, a blocking inhibitor, and a surfactant, and a second layer comprising a blend of a maleic acid-modified PVOH copolymer and a monomethyl maleate-modified PVOH copolymer, and the first layer and the second layer can be present in a ratio of about 1:200 to about 1:1, or about 1:100 to about 1:3, or about 1:20 to about 1:5 based on the total weight of the water-soluble film. The film according to this aspect can exhibit a haze % of less than about 50 as determined by the haze test described herein, and a coefficient of static friction of less than about 2 between a first portion and a second portion of the outer surface of the first layer as determined by the coefficient of friction test described herein.

[0082] The water-soluble film according to the present disclosure can include a first layer containing a blend of a monomethyl maleate-modified PVOH copolymer and a PVOH homopolymer, and a second layer containing a blend of a polyvinyl alcohol homopolymer. The first layer and the second layer are present in a ratio of about 1:200 to about 1:1, or about 1:100 to about 1:3, or about 1:20 to about 1:5, respectively, based on the total weight of the water-soluble film. The film according to this aspect, when measured by the water vapor transmission rate test method described herein, has a water vapor transmission rate of less than 25 gH2O / m 2 / day, and can exhibit a heat seal strength of at least 15 N when measured by the seal strength test described herein.

[0083] Also provided herein is a water-soluble unit dose article comprising a packet including an outer wall, the outer wall having an outer surface and an inner surface defining an inner pouch volume, the outer wall comprising a multilayer water-soluble film according to the disclosure herein and, optionally, a composition contained within the inner pouch volume.

[0084] The composition contained within the inner pouch volume can be a fabric or home care ingredient, such as those described above in connection with multiple compartment articles. The water-soluble unit dose article can include a non-domestic care composition. The non-domestic care composition can be selected from agricultural compositions, aviation compositions, food and nutritional compositions, industrial compositions, livestock compositions, marine compositions, medical compositions, commercial compositions, military and paramilitary compositions, office compositions, entertainment and park compositions, pet compositions, pool and / or water treatment compositions, and combinations thereof. The non-domestic care composition can be a pool and / or water treatment composition.

[0085] The water-soluble unit dosage article can include a household care composition. The household care composition can be selected from a light liquid detergent composition, a heavy liquid detergent composition, a hard surface cleaning composition, a laundry detergent gel, a bleaching composition, a laundry additive, a fabric enhancing composition, a shampoo, a body wash, other personal care compositions, and combinations thereof, optionally a liquid laundry detergent composition.

[0086] In another aspect of the present disclosure, the household care composition can be selected from the group consisting of a laundry composition and an automatic dishwashing composition, including a liquid laundry detergent composition.

[0087] In another aspect of the present disclosure, the household care composition can be selected from non-laundry compositions and non-automatic dishwashing compositions, for example, a light liquid detergent composition, a heavy liquid detergent composition, a hard surface cleaning composition, a bleaching composition, a shampoo, a body wash, other personal care compositions, and other compositions that are non-laundry and non-automatic dishwashing compositions, or a mixture of any of the foregoing.

[0088] The term "liquid laundry detergent composition" refers to any laundry detergent composition that includes a liquid capable of wetting and treating fabrics, including but not limited to liquids, gels, pastes, dispersions, etc. The liquid composition can preferably include a solid or gas in a finely divided form, but excludes forms that are entirely non-fluid, such as tablets or granules.

[0089] The liquid detergent composition can be used for hand fabric washing operations or can be used in automatic mechanical fabric washing operations.

[0090] In other aspects, the household care composition can be an automatic dishwashing detergent composition including components selected from surfactants, boosters, sulfonated / carboxylated polymers, silicone foam inhibitors, silicic acid, metal and / or glass care agents, enzymes, bleaching agents, bleach activators, bleach catalysts, sources of alkalinity, perfumes, dyes, solvents, fillers, and mixtures thereof.

[0091] Household care compositions can include one or more acids used to adjust the pH of the solution to an acidic pH. The household care composition can include one or more acids including, but not limited to, glycolic acid, citric acid, acetic acid, hydrochloric acid, levulinic acid, gluconic acid, etc. The household care composition can have a pH of 3 or less. The household care composition can have a pH of 2.5 or less. The household care composition can have a pH of 2 or less. The household care composition can have a pH of 1.5 or less.

[0092] The water-soluble unit dose article can include the concentration of an acid, an oxidizing agent, a base, or a combination thereof in the range of 50 wt% to 100 wt%, or 60 wt% to 100 wt%, or 70 wt% to 100 wt%, or 80 wt% to 100 wt%, or 90 wt% to 100 wt% based on the total weight of the composition contained in the water-soluble unit dose article. The concentration of an acid, an oxidizing agent, a base, or a combination thereof in the non-household care composition of the water-soluble unit dose article is in the range of 50 wt% to 100 wt%, or 60 wt% to 100 wt%, or 70 wt% to 100 wt%, or 80 wt% to 100 wt%, or 90 wt% to 100 wt% based on the total weight of the non-household care composition.

[0093] Optionally, the water-soluble unit dose article of the present disclosure can be characterized by a disintegration time of 300 seconds or less in accordance with MSTM205 in water at 23°C after exposure to a TCCA, SBS, or calcium hypochlorite composition for 6 or 8 weeks in an atmosphere of 38°C and 80% RH. The disintegration time can be controlled by the selection of the film thickness, and the resistance of the film to such harsh chemicals can be reduced, for example, by the inclusion of an antioxidant.

[0094] The surface area of the residue of the water-soluble unit dose article after testing in accordance with MSTM205 in water at 23°C after exposure to a TCCA, SBS, or calcium hypochlorite composition for 6 or 8 weeks in an atmosphere of 38°C and 80% RH can be less than about 50% of the surface area of the water-soluble unit dose before testing in accordance with MSTM205.

[0095] The water-soluble unit dose article can be provided in any dimensions suitable for fitting through the neck of a trigger spray bottle (e.g., a spray bottle having a screw top neck with a diameter of about 28 mm). The water-soluble unit dose article can optionally have a length of about 250 mm or less, or in the range of about 5 mm to about 250 mm, about 10 mm to about 250 mm, about 25 mm to about 250 mm, about 50 mm to about 225 mm, about 100 mm to about 225 mm, about 150 to about 225 mm, about 175 mm to about 225 mm, or about 200 mm. The water-soluble unit dose article can optionally have a width in the range of 50 mm or less, or about 2 mm to about 50 mm, about 5 mm to about 45 mm, about 10 mm to about 40 mm, about 15 mm to about 35 mm, or about 20 mm to about 30 mm. The water-soluble unit dose article can have a length of 175 mm to about 225 mm, or about 200 mm, and a width of about 20 mm to about 30 mm, or about 25 mm. In embodiments where the water-soluble unit dose article is provided to fit through the neck of a trigger spray bottle, the water-soluble unit dose article optionally contains a household care composition having a pH of 2 or less.

[0096] Water-soluble unit-dose articles can be heat-sealed or solution-sealed by any suitable process and apparatus, such as those already well-known in the art. For example, water-soluble unit-dose articles can be heat-sealed on three sides. For example, a water-soluble film can be folded upon itself to provide a pouch of a desired dimension, sealed at the edges opposite the fold, and sealed along one of the two remaining open edges using a heat impulse sealer. A liquid composition (e.g., a household care composition) can be filled into the pouch using an injection system such as a pump or syringe. Optionally, the water-soluble film can be stretched across a cavity of a specified dimension, and heat and vacuum can be applied to form the film into the shape of the cavity. The cavity can then be filled with a desired composition (e.g., a household care composition). The filled pouch can then be sealed with a second film. The second film can be pulled across the top of the cavity, and the side of the second film facing the filled pouch can be wetted for solution sealing. Pressure can be applied, and the filled pouch can be joined to the second film around the shaped cavity to form a composition encapsulated within the water-soluble unit-dose article. Solution sealing can be achieved using, for example, a Mespack-Cloud sampling machine.

[0097] Provided herein is a process for introducing a composition of bulk water, comprising the step of contacting a water-soluble unit-dose article described herein with bulk water, thereby dissolving at least a portion of the water-soluble film and releasing the composition into the bulk water.

[0098] Generally, the bulk water can be any bulk water that requires a non-household care composition provided therein. For example, the bulk water can be a pool or a hot spring. Generally, the temperature of the bulk water can be any temperature sufficient to dissolve or disintegrate at least a portion of the water-soluble film. The bulk water can have a temperature in the range of at least about 10°C, such as about 10°C to about 100°C, about 10°C to about 70°C, about 10°C to about 60°C, about 20°C to about 50°C, or about 20°C to about 40°C. Generally, the bulk water can be characterized by any pH value. For example, the pH of the bulk water can be in the range of about 4 to about 10, about 5 to about 9, or about 6 to about 7.

[0099] Method for making the film Processes for manufacturing PVOH films by solution casting are well known in the art. Typically, the PVOH polymer and secondary additives are dissolved in a solvent, typically water, to form a resin solution, and the solution is metered onto a casting surface and substantially dried or forced dried with heated air to form a casting film. The resulting casting film is removed from the casting surface and optionally wound onto a roller. The process can be carried out batchwise and is more efficiently carried out in a continuous process.

[0100] In the formation of a continuous film web, a solution of a resin and a secondary component is metered onto a moving casting surface, such as a continuously moving metal drum or belt, and then the solvent is substantially removed from the liquid, thereby forming a self-supporting casting film, and then peeling the resulting casting film from the casting surface is the conventional practice. The solution can optionally be metered or coated onto a carrier film, a release liner, or a removable backing, whereby, after solvent removal, the resulting casting film or coating can be separated from the carrier film, release liner, or removable backing (e.g., immediately after drying, or at a later point, e.g., before use), or can remain attached to the carrier film, release liner, or removable backing. The film or coating prepared on the carrier film, release liner, or removable backing can be self-supporting or non-self-supporting. Such carrier films, release liners, and removable backings can be made from a variety of materials known in the art, such as polyethylene, polyethylene oxide, polyethylene terephthalate, polyolefin, oriented polypropylene, polytetrafluoroethylene, polyvinyl chloride, and crosslinked polyvinyl alcohol.

[0101] Generally, the casting surface can be any suitable substrate for manufacturing polymer films well-known to those skilled in the art. The substrate can be a casting roller or drum, a casting belt, or a combination thereof. As used herein, the substrate is used to manufacture a polymer film from one or more polymer resins or polymer resin solutions. The substrate includes a substrate surface, and the substrate surface can be coated with a release coating. The polymer resin solution can be cast onto the substrate while the substrate is moving, e.g., rotating. The substrate can include stainless steel and optionally can have a stainless steel surface. The substrate can optionally include stainless steel that is plated, e.g., chrome plating, nickel plating, zinc plating, or a combination thereof.

[0102] The multilayer films according to the disclosure herein can be manufactured using a solvent band casting system. The system can be used with a band casting machine having at least first and second rotating drums that are tensioned such that the casting surface moves with the rotation of the drum, and includes tanks for mixing and / or storing a plurality of water-soluble resin solutions, each having an optional secondary additive. A multi-slot die can be used to simultaneously cast one or more resin solutions from the tanks to form a multilayer solution composition on the casting surface. A drying chamber surrounding at least a portion of the die's casting surface downline is used to remove the solvent from the multilayer solution composition as it moves in a thin sheet on the casting surface. Additionally, a release coating can be applied to the casting surface to provide one or more advantages to the film and / or the process. For example, the release coating can substantially reduce or eliminate air bubbles within the manufactured multilayer film, or the release coating can improve the ease of release of the manufactured film from the casting surface. A roll coater release coating applicator connected to the supply and a portion of the band can transfer a fluid release coating to the casting surface prior to application of the resin solution to the band. Suitable solvent band casting systems and related materials are further described in U.S. Patent Application Publication Nos. 2006 / 0081176A1 and 2007 / 0085234A1, the disclosures of which are incorporated herein by reference in their entireties.

[0103] Generally, the release coating can include one or more surfactants and an optional carrier, such as water. The release coating can include one or more surfactants and can be selected from, for example, fluorinated surfactants, non-fluorinated anionic surfactants, non-fluorinated zwitterionic surfactants, salts thereof, or any combination thereof. The anionic or zwitterionic surfactant can be non-fluorinated and can be a C6-C 30 phosphate ester, a C6-C 30 phosphate diester, a C6-C30 Carboxylate, C6-C 30 Dicarboxylate, C6-C 30 Sulfate, C6-C 30 It can contain disulfate, or salts thereof. The release coating can contain a non-fluorinated zwitterionic surfactant or a salt thereof. The release coating can contain a non-fluorinated anionic surfactant or a salt thereof. The non-fluorinated anionic surfactant is C6-C 30 Phosphate ester, or C8-C 16 Phosphate ester, C6-C 60 Phosphoric acid diester, C 16 -C 32 Phosphoric acid diester, C6-C 30 Carboxylate, C6-C 30 Dicarboxylate, C6-C 30 Sulfate, C6-C 30 It can contain disulfate, or salts thereof. The non-fluorinated anionic surfactant is C6-C 30 Phosphate ester, or C6-C 18 Phosphate ester, C6-C 60 Phosphoric acid diester, C 18 -C 32 It can contain phosphoric acid diester, or salts thereof. The anionic surfactant can contain one or more of ammonium C6-based fluoroaliphatic phosphate ester; tridecyl alcohol ethoxylate phosphate ester, POE-12; tridecyl alcohol ethoxylate phosphate ester, POE-3; laures-11 carboxylic acid; crypt-anionic surfactant-laures-6 carboxylic acid; or sodium lauryl ether sulfate, POE-4.

[0104] As used herein, the term "non-fluorinated" refers to a surfactant having less than 0.01% by weight of fluorine based on the total molecular weight of the compound, or less than 0.001% by weight of fluorine based on the total molecular weight of the compound, or less than 0.0001% by weight of fluorine based on the total molecular weight of the compound.

[0105] The release coating can include a fluorosurfactant, for example, a perfluoroalkyl-containing compound. The fluorosurfactant can include a solution of ZONYL FSP surfactant (E.I. du Pont de Nemours and Company). A range of about 0.05 wt% to about 5.0 wt% of the surfactant in the release coating is contemplated. The amount of surfactant required to provide sufficient wetting can vary depending on the film coated on the band. Other products may require higher concentrations to improve release characteristics. Hard surface spreading wetting is more efficient with higher surfactant concentrations until the surfactant solution reaches the critical micelle concentration (CMC). This concentration represents the threshold at which additional surfactant produces no further efficiency in spreading wetting. However, increasing the concentration beyond the CMC can improve wetting by the polymer solution and improve the release characteristics of some film formulations.

[0106] The release coating can be applied to the surface of a substrate before casting a polymer resin or a polymer resin solution on the surface-coated substrate and, optionally, subsequently dried. The release coating, when applied to the surface of the substrate, can have a pH of from about 1 to about 5 before drying the release coating on the surface of the substrate. When the surfactant includes a non-fluorinated anionic surfactant, a non-fluorinated zwitterionic surfactant, salts thereof, and combinations thereof, the release coating, when applied to the surface of the substrate, can have a pH of from about 1 to about 8 or from about 1 to about 5 before drying the release coating on the surface of the substrate. For example, the release coating, when applied to the surface of the substrate, can have a pH of about 1, about 1.5, about 2, about 2.5, about 3, about 3.5, about 4, about 5, about 6, about 7, or about 8. The release coating, when applied to the surface of the substrate, can have a pH of from about 1 to about 7, or from about 1 to about 6, or from about 1 to about 4, or from about 1 to about 3, or from about 2 to about 7, or from about 2 to about 6, or from about 2 to about 5, or from about 2 to about 4, or from about 2 to about 3, or from about 3 to about 7, or from about 3 to about 5, or from about 1.5 to about 3.5, or from about 4 to about 7 before drying the release coating on the surface of the substrate.

[0107] Generally, the release coating can have a surfactant concentration in the range of about 0.001 wt% to about 100 wt% based on the total weight of the release coating. The release coating can have a surfactant concentration in the range of about 0.001 wt% to about 20 wt% before drying the release coating on the surface of the substrate. For example, the release coating can have a surfactant concentration in the range of about 0.001 wt% to about 10 wt%, or about 0.01 wt% to about 5 wt%, or about 0.01 wt% to about 4 wt%, or about 0.01 wt% to about 3 wt%, or about 0.01 wt% to about 2 wt%, or about 0.05 wt% to about 2 wt%, or about 0.1 wt% to about 2 wt%, or about 0.5 wt% to about 2 wt% before drying the release coating on the surface of the substrate. The release coating can have a surfactant concentration in the range of about 0.01 wt% to about 4.00 wt% based on the total weight of the release coating before drying the release coating on the surface of the substrate. The release coating can have a surfactant concentration in the range of about 0.05 wt% to about 2.00 wt% based on the total weight of the release coating before drying the release coating on the surface of the substrate. After drying the release coating on the surface of the substrate, the release coating can have a surfactant concentration in the range of about 2.5 wt% to about 100 wt% based on the total weight of the release coating. For example, after drying the release coating on the surface of the substrate, the release coating can have a surfactant concentration in the range of about 3 wt% to about 100 wt%, or about 4 wt% to about 90 wt%, or about 4 wt% to about 80 wt%, or about 4 wt% to about 70 wt%, or about 4 wt% to about 50 wt%, or about 4 wt% to about 30 wt%, or about 4 wt% to about 20 wt%, or about 4.7 wt% to about 100 wt%, or about 5 wt% to about 90 wt% based on the total weight of the release coating. The release coating can have a surfactant concentration in the range of about 4.7 wt% to about 100 wt% based on the total weight of the release coating after drying the release coating on the surface of the substrate. For example, the release coating can contain an amount of ZONYL surfactant in the range of about 0.05 wt% to about 5.0 wt% based on the total weight of the release coating.

[0108] Generally, the release coating described herein can have a hydrophilic-lipophilic balance in the range of about 1 to about 30. The release coating can have a hydrophilic-lipophilic balance in the range of about 1 to about 20, or about 1 to about 18, or about 1 to about 17, or about 1 to about 16, or about 1 to about 15, or about 2 to about 17, or about 3 to about 17, or about 4 to about 15, or about 5 to about 12, or about 8 to about 12. The release coating can have a hydrophilic-lipophilic balance in the range of about 1 to about 20. The release coating can have a hydrophilic-lipophilic balance in the range of about 3 to about 17.

[0109] Generally, the release coating has a thickness of about 0.1 nm to about 100 nm on the surface of the substrate. The release coating can have a thickness of about 0.1 nm to about 80 nm, or about 0.1 nm to about 60 nm, or about 0.1 nm to about 40 nm, or about 0.1 nm to about 40 nm, or about 0.1 nm to about 20 nm, or about 0.1 nm to about 10 nm, or about 1 nm to about 10 nm, or about 1 nm to about 5 nm on the surface of the substrate. The release coating can have a thickness of about 0.1 nm to about 40 nm on the surface of the substrate. The release coating can have a thickness of about 0.1 nm to about 10 nm on the surface of the substrate.

[0110] The amount of water in the measured resin solution of polyvinyl alcohol, additional resin, and / or secondary components for film casting can optionally be selected such that when the solution is heated to the casting temperature, the solution has a maximum solids level below the viscosity inflection point. Methods for determining the amount of solids at the viscosity inflection point are known in the art. Generally, the measured resin solution can contain from about 60% to 85% water, or from about 60% to 75% water, to provide a solution suitable for casting. The viscosity of each resin solution at 175°F (about 80°C) can be, for example, at least about 5,000 cPs, or at least about 6,000 cPs, or at least about 7,000 cPs, or at least about 8,000 cPs, or at least about 9,000 cPs. The viscosity of each resin solution at 175°F (about 80°C) can be, for example, about 15,000 cPs or less, or 14,000 cPs or less, or about 13,000 cPs or less, or about 12,000 cPs or less, or about 11,000 cPs or less.

[0111] The resin concentration of the resin solution is not particularly limited. The first and second resin solutions can independently have a resin concentration in the range of from about 1 wt% to about 50 wt%, or from about 5 wt% to about 45 wt%, or from about 10 wt% to about 40 wt%, or from about 20 wt% to about 35 wt% based on the total weight of each resin solution. The first resin solution can have a resin concentration in the range of from about 1 wt% to about 50 wt%. The second resin solution can have a resin concentration in the range of from about 5 wt% to about 37 wt%.

[0112] The resin solution can be cast at any suitable temperature such that the film, optionally, has a temperature in the range of about 50 °C to about 105 °C during drying. Without wishing to be bound by theory, if the resin solution and film temperature drop significantly below about 50 °C, the amount of time required to dry the film undesirably increases, and the length of the drying chamber required to completely dry the casting solution increases to an undesirable extent. Further, without wishing to be bound by theory, if the solution and film temperature increase significantly above about 105 °C, the solvent can boil rapidly from the film, resulting in defects on the film surface such as holes or blisters in the finished film and / or promoting undesirable reactions between adjacent PVOH backbone chains, resulting in a film with reduced solubility.

[0113] In a continuous or semi - continuous casting process, the moving casting surface can have any desired line speed, for example, in the range of about 5 m / min to about 50 m / min. The line speed can sometimes affect the properties of the resulting film, such as physical properties, thickness, residual moisture content, and film quality. Generally, as the line speed decreases, assuming a constant solution delivery rate, the thickness of the resulting film increases, and as the line speed increases, the thickness of the resulting film decreases. Generally, as the line speed increases, the residence time of the film in a fixed - size dryer decreases, thereby requiring an increase in the drying temperature, and at sufficiently high temperatures, drying defects or sticking can result. In contrast, as the line speed decreases, the residence time of the film in the dryer increases.

[0114] Method for making a co - cast multi - layer film To prepare a co-cast multilayer film, two or more resin solutions described herein are simultaneously supplied to a multi-slot die under conditions suitable to achieve a uniform multilayer film in a chatter-free manner. The resin solutions can be filtered to remove particles larger than 25 microns and then supplied to the die. First, the second (e.g., bottom) resin solution is cast through the bottom slots of the multi-slot die to form a second solution layer on the substrate. Before drying the second solution layer, the first (e.g., top) resin solution is cast through the first top slots of the multi-slot die to form a first solution layer in contact with the second solution layer. The resulting multilayer solution composition can be conveyed onto the substrate through one or more ovens operated at a temperature sufficient to effect drying of the multilayer solution composition and formation of a multilayer film, optionally a self-supporting multilayer film. The drying temperature is not particularly limited. For example, the multilayer solution composition can be dried by exposure to a temperature in the range of about 70 °C to about 180 °C, or about 80 °C to about 160 °C, or about 90 °C to about 150 °C, or about 100 °C to about 150 °C, or about 100 °C to about 140 °C. Further, the drying time is not particularly limited. For example, drying the multilayer solution composition can be carried out for a time in the range of about 1 minute to about 60 minutes, or about 1 minute to about 30 minutes, or about 1 minute to about 20 minutes, or about 5 minutes to about 20 minutes, or about 5 minutes to about 15 minutes, or about 10 minutes to about 15 minutes. After exiting the oven, the film can be cooled by conveying the substrate over one or more cooling rolls. The cooling time is not particularly limited and, for example, cooling can be carried out for a time in the range of about 1 second to about 30 minutes, or about 1 second to about 20 minutes, or about 30 seconds to about 10 minutes, or about 1 minute to about 5 minutes. The film can then be pulled under tension to peel it from the substrate and conveyed to a take-up roller.

[0115] FIG. 3 is a perspective view of a multi-slot die 1 that can be used to prepare the co-cast multi-layer film of the present disclosure. FIG. 4 shows the die 1 of FIG. 3 in a side view. The multi-slot die 1 includes a wedge-shaped central die body 10 that separates an upper die body 20 and a lower die body 40 such that two supply slots 32 and 52 are formed. The resin solution is supplied to the die through an upper injection port 36 and a lower injection port 56. The upper offset shims 26a-d and the lower offset shims 46a-d are thin sheet materials that are inserted into offset blocks 24a-d and 44a-d, respectively, and control the degree of "overbite" 62, or how far the upper die lip 28 projects in front of the lower die lip 48. These shims are important for controlling the pressure distribution in the machine or down-web direction in which the die lips 28 and 48 are placed adjacent to a casting surface such as a band. The upper body shims 30 and the lower body shims 50 are thin sheet materials that function as spacers between the central die body 10 and the upper die body 20 and the lower die body 40, respectively. These shims 30 and 50 set the spacing between the two bodies, or die gap, and thus set the heights 34 and 54 of the feed slots 32 and 52 through which each solution flows. Appropriate die gap setting is important for maintaining the uniformity of the flow across the width of each web. Inappropriate die gap setting can result in a film with non-uniform thickness in the lateral direction. The side view shown in FIG. 4A also shows the upper 26a and lower 46a offset shims, as well as the upper 30 and lower 50 body shims. An enlarged portion of FIG. 4A, FIG. 4B, illustrates the level of "overbite" 62 that can be controlled by adjusting the upper offset shims 26a-d and the lower offset shims 46a-d. FIG. 5 shows a schematic view of the die 1 in a side view with respect to a casting surface 70, illustrating the die angle ∠XYZ. The die angle is the angle between the casting surface (shown by YZ in FIG. 5) and the plane defined by the flow of the resin solution through the bottom slot of the die (shown by XY in FIG. 5).

[0116] Process conditions including, but not limited to, resin solution temperature and viscosity, die head temperature, upper and lower body shim spacing, upper and lower offset shim spacing, die angle, die gap, line pressure, and line speed can be adjusted as needed to optimize the formation of the first and second solution layers and the multilayer solution composition.

[0117] Method for producing a continuously cast multilayer film Methods for preparing continuously cast multilayer films are known in the art. Generally, a second resin solution can be cast onto a substrate to form a second resin solution layer, the second resin solution can be at least partially dried, and the first resin solution can be cast directly onto the at least partially dried second resin solution layer. The resulting multilayer composition can be conveyed onto a substrate through one or more ovens operated at a temperature sufficient to effect drying of the multilayer composition and formation of a multilayer film, optionally a self-supporting multilayer film.

[0118] The first and second resin solutions can be cast by any suitable means. For example, the second resin solution can be cast using a die such as a slot die, and the first resin solution layer can be cast using a doctor blade device or other suitable means.

[0119] Optionally, in a continuous casting process, the first resin solution can be a foamed resin solution such that the resulting multilayer film includes an upper layer that is a foamed film layer.

[0120] Dissolution, disintegration, and residue % test (MSTM205) The film can be characterized or tested for dissolution time and disintegration time according to the MonoSol test method 205 (MSTM205), which is a method known in the art. See, for example, U.S. Patent No. 7,022,656.

[0121] Apparatus and materials: 600 mL beaker Magnetic stirrer (Labline model number 1250 or equivalent) Magnetic stir bar (5 cm) Thermometer (0 to 100 °C ±1 °C) Template, stainless steel (3.8 cm × 3.2 cm) Timer (0 to 300 seconds, accuracy in seconds) Polaroid 35 mm slide mount (or equivalent) MonoSol 35 mm slide mount holder (or equivalent) Distilled water

[0122] For each film to be tested, three test specimens are cut from the film sample, which are test specimens of 3.8 cm × 3.2 cm. When cutting from the film web, the test specimens should be cut from equally spaced web areas along the transverse direction of the web. Then, each test specimen is analyzed using the following procedure.

[0123] Fix each test specimen within a separate 35 mm slide mount.

[0124] Fill the beaker with 500 mL of distilled water. Measure the water temperature with the thermometer and, if necessary, heat or cool the water to maintain the temperature at 20 °C (about 68 °F).

[0125] Mark the height of the water column. Place the magnetic stirrer on the base of the holder. Place the beaker on the magnetic stirrer, add the magnetic stir bar to the beaker, turn on the stirrer, and adjust the stirring speed until a vortex is generated that is approximately one-fifth of the height of the water column. Mark the depth of the vortex.

[0126] Fix the 35 mm slide mount to the alligator clip of the 35 mm slide mount holder such that the long edge of the slide mount is parallel to the water surface. The depth adjuster of the holder should be set so that when dropped, the end of the clip is 0.6 cm below the water surface. One of the short sides of the slide mount should be next to the side of the beaker and the other should be placed directly above the center of the stir bar so that the film surface is perpendicular to the water flow.

[0127] In one operation, drop the fixed slide and clip into the water and start the timer. Disintegration occurs when the film breaks. When all visible film has been released from the slide mount, raise the slide out of the water while continuing to monitor the solution for undissolved film fragments. When dissolution occurs, all film fragments are no longer visible and the solution becomes clear.

[0128] After 300 seconds, if any film residue remains within the frame, the percent of the surface area of the remaining film was estimated by visual inspection.

[0129] The results should include: complete identification of the sample, the individual and average disintegration and dissolution times, and the water temperature at which the sample was tested.

[0130] The film disintegration time (I) and film dissolution time (S) can each be corrected for the standard or reference film thickness using the exponential algorithm shown below in Equations 1 and 2. I 補正 =I 実測 × (reference thickness / measured thickness) 1.93 [1] S 補正 =S 実測 × (reference thickness / measured thickness) 1.83 [2]

[0131] Coefficient of Friction Test The coefficient of friction method tests the friction of two pieces of material rubbing against each other and measures the force required to move one piece relative to the other. Both the force to start the sled (static friction) and the force to keep the sled moving (kinetic friction) are measured by a load cell using ASTM D1894, "Friction Testing of Plastic Film and Sheeting".

[0132] The method uses an Instron® coefficient of friction test fixture model 2810 - 005 or equivalent, a representative diagram shown in Figure 6, and an Instron® testing machine model number 5543 or equivalent.

[0133] The test apparatus includes a friction sled 112 that holds the film sample 114 on top and a friction fixture 110 that rests on top. The sled 112 is connected to an upper grip 118 via a pull cord 120 that engages a pulley 122 fixed to the friction fixture 110. A lower coupling 124 secures the test fixture to an Instron® testing machine (not shown).

[0134] By the Instron® method BlueHill program: "System: Search for the maximum value from the start value to the end value of a specific channel; Determine the first data point going up and down by a percentage of the maximum value and assign this point as the first peak; Use the following formula to determine the coefficient of static friction: Static friction = First peak / Sled weight; Use the following formula to calculate the average load in the region from the first peak to the end value: Average load = Energy / Change in elongation; Use the following formula to determine the coefficient of kinetic friction: Kinetic friction = Average load / Sled weight."

[0135] The test specimen consists of samples having dimensions of a warp of 5 inches × 5 inches square (12.7 cm × 12.7 cm square) and a surface of 5 inches × 8 inches rectangle (12.7 cm × 20.3 cm), and forms a test area. The film thickness is considered not to affect the static COF, and the film can have a thickness of 3.0 ± 0.10 mils (or 76.2 ± 2.5 μm). The sample can be cut, for example, using a razor blade and a template of appropriate dimensions. When applicable, the sample should be cut in the long dimension parallel to the longitudinal direction of the casting film. Also, when applicable, pay attention to the 5 inches × 5 inches sample direction and orient it during the test so that the direction in which the warp is pulled is parallel to the longitudinal direction of the film sample.

[0136] The test specimen should be conditioned at 75°F ± 5°F (about 24°C ± 3°C) and a relative humidity of 35% ± 5% for 8 hours or more before the test, and the test is conducted under the same temperature and relative humidity conditions.

[0137] Installation Procedure of COF Device 1. Remove and remove the clevis pin from the lower jaw of the Instron® coefficient of friction test fixture model 2810 - 005. 2. Remove and remove the clevis pin from the upper jaw. 3. Place the lower coupling of the friction fixture on the base adapter of the Instron® testing machine model number 5543. 4. Attach it with a clevis pin. 5. Slide the loop at one end of the pull cord into the upper clevis pin and replace the locking clip. 6. Calibrate the testing machine model number 5543 7. Slide the loop at the other end of the pull cord into the hook of the friction warp. 8. Confirm that the pulley can rotate freely. 9. Move the warp until there is no slack in the pull cord and it conforms to the groove around the pulley. 10. Place the moving crosshead (upper hard part) of the Instron (registered trademark) friction coefficient test fixture. Model 2810-005 has sufficient moving space to pull the friction warp along the entire 50 mm test without the warp hitting the pulley. 11. While the crosshead is moving, hold the cord taut. 12. Use the JOG control on the Instron number 5543 control panel to set the extension limit so that the far end of the friction warp does not extend beyond the backplane of the friction fixture (the plane farthest from the pulley and perpendicular to the axis of motion). Press the GL button to set the movement limit. This prevents the friction warp from hitting the pulley during the test and ensures that the friction coefficient of the target sample is measured appropriately. 13. Now the test fixture is ready for the test.

[0138] Test Specimen Placement Procedure 1. Place the surface sample on the aluminum friction fixture in the appropriate orientation. 2. Pull the surface sample firmly across the edge of the aluminum surface and tape the sample to the bottom side of the friction fixture. 3. To avoid warping on the surface, it is important to tape along the edge of the friction fixture farthest from the coupling. 4. Confirm that the material is taut but not stretched. 5. Wrap the friction warp with a 5×5 inch sample so that the longitudinal direction of the film is parallel to the direction in which the warp is pulled. 6. While confirming that there is no extra material sticking to the surface sample, tape the tip overlapping the top of the warp. 7. Tape the other edges of the sample to the friction warp to ensure that the sample is taut on the contact surface being measured. 8. Confirm that there is no tape between the target surface of the warp and the target surface of the friction fixture. 9. The sample on the friction surface and the sample on the friction warp must be taut so that there are no wrinkles or bulges, as these will cause errors in the COF measurement. 10. Inspect the sled to confirm that there are no foreign objects touching the surface being tested. 11. To prevent unnatural adhesion from occurring between the two test pieces, attach the sled to the pull cord, place the sled very gently on the friction table, and start the test promptly. 12. Confirm that the sled is fully extended and properly placed on top of the sample placed on the friction fixture, without contacting the tape or protruding beyond the edge of the friction fixture.

[0139] Conduct the COF test 1. Test three or more test pieces for each required direction (e.g., air side - air side, or band side - band side). 2. In the combined test of the air side and the band side, the air side orientation of the film should be the film sample placed on the aluminum test surface, and the band side for the test should consist of the material wrapping around the sled. 3. Confirm that anti - static and moisture - proof gloves are worn while handling the film test pieces. Powder or moisture can compromise the accuracy of the test. 4. Cut the sample as described above, for example, using a template. 5. Place the friction sled wrapped with the first test piece at the end of the friction fixture farthest from the pulley. 6. Confirm that the pull cord is taut. 7. Open the coefficient of friction test titled "COF.im ptf" from the test screen. 8. Click the start button on the screen to start the test. 9. When the test of the test piece is completed, click ok to return the friction sled to the starting position, and replace the friction sled and the film test piece of the fixture. Repeat the test.

[0140] Water vapor transmission rate (MVTR) test The multilayer water-soluble film according to the present disclosure can be characterized by the amount of moisture permeating through the film or its layers. The permeation of moisture through one or more layers can be measured and described by the moisture vapor transmission rate (MVTR). MVTR is the amount of water permeated per day per unit area of the barrier (gH2O / m 2 / day) and is measured as such.

[0141] MVTR is measured using ASTM F-1249. Before the test, the sample is conditioned at 23 °C and 35% RH for at least 8 hours and up to 48 hours, for example, about 24 hours. The measurement is carried out at about 38 °C and 50% RH, and the coating layer is exposed to the water source.

[0142] The multilayer water-soluble film can have an MVTR of about 100 gH2O / m 2 / day or less, or about 50 gH2O / m 2 / day or less, or about 30 gH2O / m 2 / day or less, or about 20 gH2O / m 2 / day or less, or about 10 gH2O / m 2 / or less, for example, about 18 gH2O / m 2 / day or less, about 16 gH2O / m 2 / day or less, about 15 gH2O / m 2 / day or less, about 14 gH2O / m 2 / day or less, about 12 H2O / m 2 / day or less, about 10 gH2O / m 2 / day or less, about 8 gH2O / m 2 / day or less, about 7 gH2O / m 2 / day or less, about 5 gH2O / m 2 / day or less, about 3 gH2O / m 2 / day or less, about 2.5 gH2O / m 2 / day or less, about 1 gH2O / m 2 / day or less, or about 0.5 gH2O / m 2 / day or less and can have an MVTR of about 0.05 gH2O / m 2 / day to about 20 gH2O / m 2 / day, about 0.05 gH2O / m 2 / day to about 18 gH2O / m 2 / day, about 0.10 gH2O / m2 / day to approximately 16 g H2O / m 2 / day, approximately 0.15 g H2O / m 2 / day to approximately 14 g H2O / m 2 / day, approximately 0.50 g H2O / m 2 / day to approximately 12 g H2O / m 2 / day, approximately 0.75 g H2O / m 2 / day to approximately 10 g H2O / m 2 / day, approximately 10 g H2O / m 2 / day to approximately 20 g H2O / m 2 / day, approximately 12 g H2O / m 2 / day to approximately 18 g H2O / m 2 / day, approximately 14 g H2O / m 2 / day to approximately 16 g H2O / m 2 / day, approximately 0.05 g H2O / m 2 / day to approximately 10 g H2O / m 2 / day, approximately 1 g H2O / m 2 / day to approximately 8 g H2O / m 2 / day, approximately 2 g H2O / m 2 / day to approximately 6 g H2O / m 2 / day, or approximately 3 g H2O / m 2 / day to approximately 5 g H2O / m 2 in the range of / day, for example, approximately 0.05, approximately 0.1, approximately 0.5, approximately 1, approximately 1.5, approximately 2, approximately 2.5, approximately 3, approximately 3.5, approximately 4, approximately 4.5, approximately 5, approximately 5.5, approximately 6, approximately 6.5, approximately 7, approximately 7.5, approximately 8, approximately 8.5, approximately 9, approximately 9.5, approximately 10, approximately 10.5, approximately 11, approximately 11.5, approximately 12, approximately 12.5, approximately 13, approximately 13.5, approximately 14, approximately 14.5, approximately 15, approximately 15.5, approximately 16, approximately 16.5, approximately 17, approximately 17.5, approximately 18, approximately 18.5, approximately 19, approximately 19.5, or approximately 20 g H2O / m 2 can have an MVTR of / day.

[0143] Although not intending to be bound by theory, it is considered that the MVTR can vary with the thickness of the film layer. That is, as the thickness of the film layer increases, the MVTR can decrease, and as the thickness of the film layer decreases, the MVTR can increase.

[0144] Haze test Haze was measured according to ASTM D1003 using a BYK Haze-Gard I Benchtop Haze Meter. Before the test, the test specimens were conditioned at 23 °C and 35% RH for at least 8 hours and up to 48 hours, for example, about 24 hours. The measurement was carried out at 23 °C and 35% RH.

[0145] Seal Strength Test The seal strength test measures the strength of the seal between two sealed film surfaces. The sealed film surfaces can be the surfaces of two different films sealed to each other, or the surfaces of two films having the same composition, or the sealed film surface can be the surface of a single film sealed to itself.

[0146] For the collection of film data, an INSTRON tensile testing apparatus (Model 5544 tensile tester or equivalent) is used. The films can be sealed to each other by any suitable means, including heat-sealing or water-sealing methods known in the art. For example, to seal two sheets of the film with water, an ESIPROOF proofing apparatus equipped with an anilox roller 140 / 10 or equivalent can be used. Alternatively, two sheets of the film can be heat-sealed. Thus, the seal strength of the seal between two sealed film surfaces can be characterized as the watertight strength or the heat-seal strength. At least three test specimens, each cut with a reliable cutting tool to ensure dimensional stability and reproducibility, are tested in the machine direction (MD) (where applicable) for each measurement. The tests were carried out under standard laboratory conditions of 23 ± 2.0 °C and 35 ± 5% relative humidity.

[0147] Samples for measuring watertight strength can be prepared as follows. Test specimens for testing are made by cutting four 100 mm×300 mm film sheets in the machine direction (MD) to a dimension of 300 mm. In the case of two sheets, tape the four corners of one sheet to the surface. Place the other sheet on top of the taped sheet so that the appropriate surfaces are in contact. Place the remaining sheet on top such that the two surfaces to be sealed are in contact with each other on top of the other taped sheet. Tape one 100 mm end of each upper sheet and fix it to the bottom sheet. Pass the loose end of each upper sheet through an ESIPROOF proofing roller using a 140 / 10 anilox roller. Add 0.5 mL of water to the doctor blade. Pull the roller at a constant speed (75 mm / second) to coat the upper film and fix it to the lower sheet. Keep the film in intimate contact for 10 - 15 minutes. Cut a 25.4 mm wide sample in the transverse direction (TD) using a strip punch or sample cutter.

[0148] Transfer the water-sealed or heat-sealed sample to an INSTRON testing machine and conduct the test while minimizing exposure to the environment. In the seal strength test, there is a 0.50 inch (1.27 cm) spacing between the rubber grips, all four of which are flat and square. Cut three (or more) 1 inch wide (2.54 cm) samples in the machine direction (MD). Place the unsealed flap of the test specimen in the grips of the testing machine, ensuring that the test specimen is aligned with and parallel to the grips and that the test specimen is not pulled too hard within the jaws of the testing machine. The load is balanced and the test is started according to the manufacturer's instructions for the equipment. At the end of the test, the tensile force (in N units) required to tear or separate the layers is recorded as the seal strength.

Example

[0149] The following examples are provided for illustration and are not intended to limit the scope of the present invention.

[0150] To prepare the co-cast two-layer film, two resin solutions were simultaneously fed into a multi-slot die through a supply line maintained at 160°F to 180°F (about 70°C to 80°C) under conditions suitable for achieving a chatter-free, uniform multi-layer film. The processing conditions were selected to achieve a multi-layer film with a width of 13 inches to 16 inches (33 cm to 40 cm) and a thickness of 45 to 80 μm. The co-cast multi-layer film was passed through a 100-foot (30 m) heating tunnel and conveyed from the die exit onto a stainless steel belt at 4 feet to 13 feet per minute (fpm) (2 cm / s to 6.6 cm / s), the belt was peeled off under tension, and wound onto a roll.

[0151] Resin solutions for preparing a casting film, a continuous co-cast two-layer film, or a co-cast two-layer film were prepared according to the formulations described in the following examples. The resin content of the solutions was generally 12 to 37 wt%, although the films can be cast from solutions with a resin content as low as about 5.0 wt%. The solutions were mixed overnight at 175°F to 185°F (about 80°C to 85°C) using a ribbon blender prior to casting to ensure complete dissolution of the resin.

[0152] Example 1: Co-Cast Two-Layer Film with High Bio-Based Content A two-layer film comprising a PVOH-based film layer and a film layer having a high bio-based content was prepared according to the above-described co-casting multilayer film preparation procedure. The compositions of the dried upper and bottom film layers are shown in Table 1. The upper layer contained hydroxypropyl methylcellulose (HPMC, METOLOSE®, Shin-Etsu Chemical Co., Tokyo, Japan) and auxiliary components including a plasticizer and an antifoaming agent. The resin solutions for the bottom layer (PVOH) and the upper layer (HPMC) were prepared according to the stoichiometry listed in Table 1 and diluted to 24.0 wt% PVOH and 12.0 wt% HPMC, respectively. The PVOH and HPMC resin solutions were maintained at approximately 75°F and 145°F (approximately 24°C and 63°C), respectively, and the die head was maintained at approximately 180°F (approximately 80°C) during co-casting. The line speed during co-casting was in the range of 3 - 6 fpm (approximately 1.5 - 3 cm / s).

Table 1

[0153] Surprisingly, it has been found that the two-layer film of Example 1 can be formed into a pouch by thermoforming. Films containing HPMC or other cellulose as the primary or sole film-forming resin are typically too brittle to be successfully thermoformed. Thus, the simultaneous solution co-casting procedure according to the present disclosure can provide films having a high bio-based content that embody advantageous physical properties such as thermoformability, which are not typically obtained with bio-based films.

[0154] Example 2: Two-Layer Film with Low Haze and Low COF Single-layer PVOH films 2A to 2C containing silica as an anti-blocking agent in various amounts were prepared using a standard solution casting process according to the formulations listed in Table 2. Increasing the amount of silica in the film is predicted to reduce the coefficient of friction (COF) between the film and other surfaces, but also to reduce transparency, i.e., increase the degree of haze. The two-layer film 2D was prepared by continuously casting a bottom layer of the film 2B composition (without silica) and an upper layer of the film 2C composition (high silica), and the bottom layer was dried before casting the upper layer. The haze % and the coefficient of friction of the gloss with respect to the gloss of each single-layer film and two-layer film were evaluated by the test methods described herein, and these results are also included in Table 2.

[0155] Compared to film 2A, film 2B had lower haze, as predicted by the absence of silica, but showed a higher COF, and film 2C had a lower COF, as predicted by the high loading of silica, but showed higher haze. However, the double film 2D showed a low COF comparable to that of the 2× silica film and a haze comparable to that of the control film 2A having approximately the same total silica loading. Thus, the two-layer film exhibited the advantageous properties of both layers, which was a combination that was previously only possible with individual films having offsetting drawbacks.

Table 2

[0156] Example 3: Co-cast two-layer film having low haze and low COF The single-layer PVOH films 3A and 3B were prepared using a standard solution casting process according to the formulations listed in Table 3. A double-layer film 3C comprising the upper layer of the 3A composition and the bottom layer of the 3B composition was prepared by a simultaneous solution co-casting process. To prepare the two-layer film, aqueous resin solutions having the stoichiometry corresponding to the 3A and 3B compositions were prepared, but diluted to PVOH concentrations of 31.5 wt% and 28.7 wt%, respectively. The resin solutions were simultaneously fed into a multi-slot die and co-cast onto a continuously moving metal band, with the 3B solution being fed through the bottom die slot and the 3A solution being fed through the upper die slot. The resin solutions were maintained at 180°F (about 80°C) during casting and filtered through a medium to remove particles greater than 25 μm when the solutions were fed into the multi-slot die. The body shim spacing was 0.01 inch (0.254 mm) at the upper and bottom slots. The upper offset shim spacing was 0.005 inch (0.127 mm) and the bottom offset shim spacing was 0.01 inch (0.254 mm). During casting, the die angle was adjusted between 48.5° and 50.1° and the die diverting gap was adjusted between 0.025 inch and 0.040 inch (0.635 mm and 1.016 mm). The line speed was in the range of 6 - 10 fpm (about 3 - 5 cm / s). The upper and bottom die slots were maintained between about 140°F and 180°F (about 60°C and 80°C) during casting. The co-cast two-layer film was conveyed from the die exit through a heating tunnel having heating zones maintained at about 310°F and about 230°F (about 155°C and 110°C) to dry the co-cast film.

Table 3

[0157] Table 3 shows that the simultaneously co-cast double-layer film exhibited the favorable attributes of both component layers, namely, a low coefficient of friction and a low haze, without any offsetting drawbacks.

[0158] Figure 7 shows optical microscope images of cross-sections of the co-cast double-layer film 3C obtained by cutting the film along the longitudinal direction (MD, shown in the left image) or the transverse direction (TD, shown in the right image), respectively. The images in Figure 6 are shown in the same orientation as the film was cast, i.e., the bottom film layer in each image is the layer of the co-cast film that was in direct contact with the casting band. Figure 7 shows that the component layers of the co-cast film are highly integrated and that minimal mixing of the layers occurred during the simultaneous solution co-casting process. Shown for comparison in Figure 8 is a cross-sectional image of a double-layer film having the same bottom and top layer compositions as the film 3C prepared by a continuous casting process, where the bottom layer was cast from solution and dried, and the top layer was cast on the dried bottom layer film from solution. As in Figure 7, the left and right images show cross-sections taken in the MD and TD, respectively.

[0159] A bilayer film 3F with a composition similar to the bilayer film 3C was prepared by a simultaneous solution co-casting process, demonstrating that very thin film layers are accessible by the co-casting process disclosed. The bilayer film 3F was prepared by simultaneously co-casting the bottom layer of composition 3D and the top layer of composition 3E, as shown in Table 4. Similar to film 3C, the top layer of film 3F contains silica and the bottom layer does not. The flow rates of the resin solutions through the multi-slot die were controlled separately to provide dry film thicknesses of 70 microns and 1 micron for the bottom and top film layers, respectively. Table 4 includes the coefficient of friction and haze data for the bilayer film, as well as the coefficient of friction and haze data for single-layer films having the compositions of the top and bottom layers of the bilayer film. Despite having a very thin top silica-containing layer, film 3F embodies an advantageous combination of a low coefficient of friction and low haze. The results shown in Table 4 demonstrate that very thin top film layers are accessible by simultaneous co-casting.

Table 4

[0160] Example 4: A two-layer film having a high moisture barrier and high seal strength A two-layer film 4C comprising an upper layer of the 4A composition and a bottom layer of the 4B composition listed in Table 5 was prepared by a simultaneous solution co-casting process. To prepare the two-layer film, aqueous resin solutions having stoichiometric amounts corresponding to the dry film formulations 4A and 4B were prepared and diluted to PVOH concentrations of 30.7 wt% and 36.6 wt% respectively for casting. The resin solutions were simultaneously fed into a multi-slot die and co-cast onto a continuously moving metal band, with the 4B solution being fed through the bottom die slot and the 4A solution being fed through the upper die slot. The resin solutions were maintained at 180°F (about 80°C) during casting and filtered through a medium to remove particles larger than 25 μm when the solutions were fed into the multi-slot die. The body shim spacing was 0.015 inches at the upper and bottom slots. The upper offset shim spacing was 0.002 inches (0.05 mm) and the bottom offset shim spacing was 0.01 inches (0.254 mm). During casting, the die angle was adjusted between 48° and 60°, and the die diverting gap was set at 0.025 inches (0.635 mm). The line speed was in the range of 2 - 6 fpm (about 1 - 3 cm / s). The upper and bottom die slots were maintained between about 140°F and 180°F (about 60°C and 80°C) during casting. The co-cast two-layer film was conveyed from the die exit through a heating tunnel having heating zones maintained at about 310°F and about 230°F (about 155°C and 110°C) to dry the co-cast film. The two-layer film 4C had a heat seal strength of 13.7 N.

Table 5

[0161] Example 5: A two-layer film having a high moisture barrier and high seal strength A single-layer PVOH film having the dry film compositions 5A and 5B of Table 6 was prepared using a standard solution casting process. The continuous casting two-layer film 5C comprises a 78 μm bottom layer of composition 5B and an 11 μm upper layer of composition 5A. As shown in Table 6, film 5A exhibits high heat seal strength but also high water vapor transmission, while film 5B provides a high barrier to water vapor transmission but exhibits low seal strength. However, the two-layer film 5C exhibits the advantageous properties of both component films: high heat seal strength approximately the same as that of the single-layer film 5A and low water vapor transmission rate approximately the same as that of the single-layer film 5B, without the compensating drawbacks.

Table 6

[0162] Example 6: Continuous Casting Two-Layer Film with a Foamed Film Layer A two-layer film containing a foamed film layer as the first (i.e., upper) layer was prepared by a continuous casting process. A second resin solution containing water, 36 wt% anionic-modified PVOH resin, plasticizer, other additives, and an antifoaming agent was prepared by mixing using a ribbon blender. A first resin solution containing water, 36 wt% anionic-modified PVOH resin, plasticizer, other additives, and no antifoaming agent was prepared by mixing using a ribbon blender. Mixing the first resin solution provided a foamed resin solution having a volume approximately 30% greater than the volume of the resin solution before mixing. Mixing the second resin solution did not significantly increase its volume. The increase in volume in the first resin solution was due to the incorporation of air via foam formation. The foamed first resin solution was stable, but pumping the foamed resin solution was more difficult than pumping the second (i.e., non-foamed) resin solution.

[0163] The lower part of the two-layer film, in this case the bottom film layer, was produced by casting a second resin solution onto a substrate through the bottom slots of the die and partially drying the bottom film layer by applying heat. The upper film layer of the two-layer film was produced by casting a (foamed) first resin solution directly onto the partially dried bottom film layer using a doctor blade device, and drying the resulting multilayer composition to provide the two-layer film.

[0164] The two-layer film was stable in that the bottom (non-foamed) layer and the top (foamed) layer did not easily peel from each other.

[0165] Example 7: Simultaneous co-casting two-layer film with a foamed film layer The first and second resin solutions described in Example 6 were prepared, and the first resin solution was mixed using a ribbon blender as described in Example 6 to form a foamed resin solution. Next, the second and (foamed) first resin solutions were simultaneously fed into a multi-slot die. The second resin solution was cast onto a continuously moving substrate (the running speed is referred to as the "line speed"), and the first resin solution was cast directly onto the second resin solution so that the second resin solution was fed through the lower die slots and the (foamed) first resin solution was fed through the upper die slots to form a two-layer solution composition. The die head was maintained at 75 - 85 °C (167 - 185 °F) during co-casting. The resulting two-layer solution composition was then passed through an oven to dry the film and form a two-layer film.

[0166] Several parameters, such as the line speed, were varied during co-casting to attempt to achieve optimal casting conditions. Under some casting conditions, the upper resin solution layer did not appear to be completely stable. In particular, as the line speed increased, the upper resin solution layer appeared to de-wet from the bottom resin solution layer. Thus, the line speed can be controlled to provide a stable multi-layer film structure, i.e., by reducing the speed as necessary. Further, as described in Example 6, the foamed resin solution was more difficult to pump from its holding tank to the casting apparatus than the non-foamed resin solution. Thus, a higher pumping pressure can be used for the foamed resin solution compared to the pressure in the non-foamed resin solution. In-line mixing of the upper resin solution to form the foamed resin solution is contemplated to provide more consistent casting results.

[0167] The foregoing description is shown only for clarity of understanding, and since modifications within the scope of the present invention may be apparent to those skilled in the art, no unnecessary limitation should be understood therefrom.

[0168] All patents, publications, and references cited herein are hereby incorporated by reference in their entirety. In case of conflict between the present disclosure and the incorporated patents, publications, and references, the present disclosure shall prevail.

Claims

1. A water-soluble film comprising a first layer and a second layer in contact with each other, wherein the first layer comprises a first water-soluble resin comprising a polyvinyl alcohol homopolymer, a polyvinyl alcohol copolymer, or a blend thereof, and the second layer comprises a second water-soluble resin comprising a polyvinyl alcohol homopolymer, a polyvinyl alcohol copolymer, or a blend thereof, and the water-soluble film is obtained by simultaneous solution casting of a first resin solution comprising the first water-soluble resin and a second resin solution comprising the second water-soluble resin.

2. wherein the second layer comprises an outer surface, When the film is sealed to itself by a first portion of the outer surface of the second layer that is sealed to a second portion of the outer surface of the second layer, it has a watertight strength of about 10 N or more, or about 12 N or more, or about 15 N or more based on a seal strength test, and based on a water vapor transmission rate test method, about 100 g / m 2 per day or less, or about 50 g / m 2 per day or less, or about 30 g / m 2 per day or less of water vapor transmission rate, the water-soluble film according to claim 1.

3. wherein the first layer comprises a blocking inhibitor, and the amount of the blocking inhibitor in the first layer (as a percentage of the total weight of the first layer) is greater than the amount of the blocking inhibitor in the second layer (as a percentage of the total weight of the second layer), wherein the first layer has a first surface that forms the outer surface of the film, The combination of haze (%) and coefficient of static friction ("COF") is within the polygon defined by the vertices (haze (%), static COF) of about (0.03, 13), about (59, 0.5), about (10, 0.1), and about (0.1, 0.1), or within the polygon defined by the vertices (haze (%), static COF) of about (0.03, 10), about (55, 0.5), about (10, 0.1), and about (0.1, 0.1). The water-soluble film according to claim 1.

4. The water-soluble film according to claim 3, wherein the first layer comprises a blocking inhibitor in an amount in the range of about 2% to about 10% by weight of the first layer.

5. The water-soluble film according to claim 4, wherein the first layer comprises a blocking inhibitor in an amount in the range of about 3.5% to about 6.5% by weight of the first layer.

6. The water-soluble film according to any one of claims 3 to 5, wherein the second layer is substantially free of a blocking inhibitor.

7. The water-soluble film according to any one of the preceding claims, wherein the weight average molecular weight of the first water-soluble resin is greater than or equal to the weight average molecular weight of the second water-soluble resin.

8. The water-soluble film according to any one of the preceding claims, wherein the degree of hydrolysis of the first water-soluble resin is greater than or equal to the degree of hydrolysis of the second water-soluble resin.

9. The water-soluble film according to any one of the preceding claims, wherein the first water-soluble resin contains a polyvinyl alcohol copolymer.

10. The water-soluble film according to any one of the preceding claims, wherein the second water-soluble resin contains a polyvinyl alcohol copolymer.

11. The water-soluble film according to any one of the preceding claims, wherein the first water-soluble resin contains a blend of a polyvinyl alcohol homopolymer and a polyvinyl alcohol copolymer.

12. The water-soluble film according to any one of claims 9 to 11, wherein the polyvinyl alcohol copolymer constituting the first water-soluble resin contains an anion-modified polyvinyl alcohol.

13. The water-soluble film according to claim 12, wherein the polyvinyl alcohol copolymer constituting the first water-soluble resin has an anion group content of about 0.5 mol% to about 10 mol% based on the total amount of the polyvinyl alcohol copolymer of the first water-soluble resin.

14. The water-soluble film according to any one of the preceding claims, wherein the second water-soluble resin contains a blend of a polyvinyl alcohol homopolymer and a polyvinyl alcohol copolymer.

15. The water-soluble film according to any one of claims 10 to 14, wherein the polyvinyl alcohol copolymer constituting the second water-soluble resin contains an anion-modified polyvinyl alcohol.

16. The water-soluble film according to claim 15, wherein the polyvinyl alcohol copolymer constituting the second water-soluble resin has an anion group content of about 0.5 mol% to about 10 mol% based on the total amount of the polyvinyl alcohol copolymer of the second water-soluble resin.

17. The water-soluble film according to any one of claims 11 to 16, wherein the amount of the polyvinyl alcohol homopolymer constituting the first water-soluble resin is greater than or equal to the amount of the polyvinyl alcohol copolymer constituting the first water-soluble resin.

18. The water-soluble film according to claim 17, wherein the first water-soluble resin contains the polyvinyl alcohol homopolymer in an amount in the range of about 35% by weight to about 45% by weight based on the total weight of the first layer.

19. The water-soluble film according to claim 17 or 18, wherein the first water-soluble resin contains the polyvinyl alcohol copolymer in an amount in the range of about 20% by weight to about 30% by weight based on the total weight of the first layer.

20. The water-soluble film according to any one of claims 11 to 16, wherein the first water-soluble resin contains a greater amount of polyvinyl alcohol copolymer than polyvinyl alcohol homopolymer.

21. The water-soluble film according to claim 20, wherein the second water-soluble resin contains the polyvinyl alcohol homopolymer in an amount in the range of about 35% by weight to about 45% by weight based on the total weight of the second layer.

22. The water-soluble film according to claim 20 or 21, wherein the second water-soluble resin contains the polyvinyl alcohol copolymer in an amount in the range of about 20% by weight to about 30% by weight based on the total weight of the second layer.

23. The anionic-modified polyvinyl alcohol constituting the first water-soluble resin and / or the second water-soluble resin contains an anionic monomer unit derived from a monomer selected from the group consisting of vinyl acetate, alkyl acrylate, maleic acid, monoalkyl maleate, dialkyl maleate, monomethyl maleate, dimethyl maleate, maleic anhydride, fumaric acid, monoalkyl fumarate, dialkyl fumarate, monomethyl fumarate, dimethyl fumarate, fumaric anhydride, itaconic acid, monomethyl itaconate, dimethyl itaconate, itaconic anhydride, citraconic acid, monoalkyl citraconate, dialkyl citraconate, citraconic anhydride, mesaconic acid, monoalkyl mesaconate, dialkyl mesaconate, mesaconic anhydride, glutaconic acid, monoalkyl glutaconate, dialkyl glutaconate, glutaconic anhydride, vinyl sulfonic acid, alkyl sulfonic acid, ethylene sulfonic acid, 2-acrylamido-1-methylpropanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-methylacrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl acrylate, their alkali metal salts, their esters, and combinations thereof. The water-soluble film according to claim 13 or 16.

24. The water-soluble film according to claim 23, wherein the anionic monomer unit is derived from a monomer selected from the group consisting of maleic acid, monoalkyl maleate, dialkyl maleate, maleic anhydride, alkali metal salts thereof, esters thereof, and combinations thereof.

25. The water-soluble film according to claim 24, wherein the anionic monomer unit is derived from a monomer selected from the group consisting of maleic acid, monomethyl maleate, dimethyl maleate, maleic anhydride, alkali metal salts thereof, esters thereof, and combinations thereof.

26. The water-soluble film according to any one of the preceding claims, wherein the first water-soluble resin comprises a polyvinyl alcohol copolymer having a degree of hydrolysis in the range of about 80% to about 99%.

27. The water-soluble film according to any one of the preceding claims, wherein the second water-soluble resin comprises a polyvinyl alcohol copolymer having a degree of hydrolysis in the range of about 80% to about 99%.

28. The water-soluble film according to any one of the preceding claims, wherein the first water-soluble resin comprises a polyvinyl alcohol homopolymer having a degree of hydrolysis in the range of about 80% to about 99%.

29. The water-soluble film according to any one of the preceding claims, wherein the second water-soluble resin comprises a polyvinyl alcohol homopolymer having a degree of hydrolysis in the range of about 80% to about 99%.

30. A water-soluble film comprising a first layer and a second layer in contact with each other, wherein the first layer comprises a first water-soluble resin comprising a biobased polymer, and the second layer comprises a second water-soluble resin comprising a polyvinyl alcohol (PVOH) homopolymer, a polyvinyl alcohol copolymer, or a blend thereof, The water-soluble film, wherein the water-soluble film is obtained by simultaneous solution casting of the first layer and the second layer.

31. The water-soluble film according to claim 30, wherein the first water-soluble resin comprises a cellulose polymer.

32. The water-soluble film according to claim 31, wherein the first water-soluble resin comprises hydroxypropyl methylcellulose.

33. The water-soluble film according to any one of the preceding claims, wherein the first layer further comprises a plasticizer.

34. The water-soluble film according to any one of the preceding claims, wherein the second layer further comprises a plasticizer.

35. The plasticizer that constitutes the first layer and / or the plasticizer that constitutes the second layer is independently selected from the group consisting of glycerol, trimethylolpropane, sorbitol, propylene glycol, dipropylene glycol, polypropylene glycol, diglycerol, 2-methyl-1,3-propanediol, and combinations thereof. The water-soluble film according to claim 33 or 34.

36. The water-soluble film according to any one of the preceding claims, wherein the first layer further comprises a surfactant.

37. The water-soluble film according to any one of the preceding claims, wherein the second layer further comprises a surfactant.

38. The surfactant that constitutes the first layer and / or the surfactant that constitutes the second layer is independently selected from the group consisting of polyoxyethylenated polyoxypropylene glycol, alcohol ethoxylate, alkylphenol ethoxylate, tertiary acetylenic glycol, alkanolamide, polyoxyethylenated amine, quaternary ammonium salt, quaternized polyoxyethylenated amine, amine oxide, N-alkyl betaine, sulfobetaine, and mixtures thereof. The water-soluble film according to claim 36 or 37.

39. The water-soluble film according to any one of the preceding claims, wherein the thickness of the film is in the range of about 40 microns to about 100 microns.

40. The water-soluble film according to claim 39, wherein the thickness of the first layer and the thickness of the second layer are independently in the range of about 1 micron to about 99 microns.

41. The water-soluble film according to claim 40, wherein the thickness of the first layer and the thickness of the second layer are independently in the range of about 30 microns to about 70 microns.

42. The water-soluble film according to claim 41, wherein the thickness of the first layer and the thickness of the second layer are independently in the range of about 20 microns to about 50 microns.

43. The water-soluble film according to any one of claims 1 to 38, wherein the first layer has a thickness in the range of about 1 micron to about 5 microns.

44. The water-soluble film according to any one of claims 1 to 38 or 43, wherein the second layer has a thickness in the range of about 40 microns to about 75 microns.

45. The water-soluble film according to any one of the preceding claims, wherein a film having the same composition and thickness as the first layer has a dissolution time of 300 seconds or less in water having a temperature of 20 °C or less based on the MST-205 dissolution test method.

46. The water-soluble film according to any one of the preceding claims, wherein a film having the same composition and thickness as the first layer has a dissolution time of 200 seconds or less in water having a temperature of 20 °C or less based on the MST-205 dissolution test method.

47. The water-soluble film according to any one of the preceding claims, when the second layer has an outer surface and the film is sealed to itself by a first portion of the outer surface of the second layer to which the film is sealed to a second portion of the outer surface of the second layer, has a watertight strength in the range of about 5 N to about 18 N, or about 12 N or more, based on a seal strength test.

48. The water-soluble film according to any one of the preceding claims, when the film is sealed to itself by a first portion of the second layer to which the film is sealed to a second portion of the second layer, has a watertight strength in the range of about 10 N to about 18 N, based on a seal strength test.

49. The film has a water vapor transmission rate of about 100 g / m 2 or less per 24 hours, or about 50 g / m 2 or less per 24 hours, or about 30 g / m 2 The water-soluble film according to any one of the preceding claims, having a water vapor transmission rate as described above.

50. The water-soluble film according to any one of the preceding claims, wherein the first layer and the second layer are in continuous contact with each other.

51. The water-soluble film according to any one of the preceding claims, wherein the first layer and the second layer are integrally connected.

52. The water-soluble film according to any one of the preceding claims, wherein the first layer and the second layer are bonded to each other and lack a separate intermediate film between the films.

53. A water-soluble unit-dose article comprising an outer wall comprising the water-soluble film according to any one of the preceding claims, wherein the outer wall comprises an outer surface and an inner surface, the outer surface of the outer wall comprises the first layer of the water-soluble film, and the inner surface of the outer wall comprises the second layer of the water-soluble film, the inner surface of the outer wall defines an internal pouch volume, Optionally, a composition is contained in the internal pouch volume, the water-soluble unit-dose article.

54. The water-soluble unit-dose article according to claim 53, wherein the article contains a composition contained in the internal pouch volume, and the composition is a cleaning and / or household care composition.

55. The water-soluble unit-dose article according to claim 53, wherein the article contains a composition contained in the internal pouch volume, and the composition is a non-domestic care composition.

56. A process for preparing a multilayer water-soluble film, comprising: (a) simultaneously casting at least a first water-soluble resin solution and a second water-soluble resin solution onto the surface of a substrate, wherein the second water-soluble resin solution is cast in contact with the substrate, and the first water-soluble resin solution is cast in contact with the second water-soluble resin solution, to form a multilayer structure comprising a second solution layer containing the second water-soluble resin in contact with the substrate and a first solution layer containing the first water-soluble resin in contact with the second solution layer; the step of simultaneously casting to form; (b) drying the multilayer structure to form a multilayer water-soluble film comprising at least a first layer and a second layer; (c) optionally, peeling the multilayer water-soluble film from the surface of the substrate.

57. The process according to claim 56, wherein the first water-soluble resin solution is an aqueous solution.

58. The process according to claim 56 or 57, wherein the second water-soluble resin solution is an aqueous solution.

59. The process according to any one of claims 56 to 58, wherein the first water-soluble resin solution has a water-soluble resin concentration of about 1 wt% to 50 wt%.

60. The process according to any one of claims 56 to 59, wherein the second water-soluble resin solution has a water-soluble resin concentration of about 5 wt% to 37 wt%.

61. The process according to any one of claims 56 to 60, wherein the surface of the substrate is metal or coated metal.

62. The process according to any one of claims 56 to 61, wherein the surface of the substrate is selected from the group consisting of stainless steel, chromium-plated steel, nickel-plated steel, zinc-plated steel, and combinations thereof.

63. The process according to claim 62, wherein the surface of the substrate is stainless steel.

64. The process according to any one of claims 56 to 63, wherein the substrate is a casting roller, a casting drum, a casting belt, or a combination thereof.

65. The process according to claim 64, wherein the substrate is a casting belt.

66. The process according to any one of claims 56 to 65, wherein the surface of the substrate is coated with a release coating prior to the co-casting step.

67. The process according to claim 66, wherein the release coating is selected from the group consisting of non-fluorinated anionic surfactants, non-fluorinated zwitterionic surfactants, salts thereof, and combinations thereof.

68. The process according to any one of claims 56 to 67, wherein drying comprises exposing the multilayer structure to a high temperature environment, optionally at a temperature in the range of about 82°C to about 160°C.

69. The process according to claim 68, wherein the temperature is in the range of about 100°C to about 150°C.

70. The process according to any one of claims 56 to 69, wherein drying occurs for about 60 seconds to about 20 minutes.

71. The process according to any one of claims 56 to 70, wherein the viscosity of each of the first water-soluble resin solution and the second water-soluble resin solution at 175°F is in the range of about 5,000 cPs to about 15,000 cPs.

72. The process according to any one of claims 56 to 71, further comprising (d) peeling the water-soluble film from the surface of the substrate.

73. The process according to any one of claims 56 to 72, further comprising cooling the water-soluble film prior to peeling the water-soluble film from the surface of the substrate.

74. The process according to claim 73, wherein cooling occurs for about 1 second to about 20 minutes.

75. Simultaneously casting comprises simultaneously passing the first water-soluble resin solution through a first slot of a multi-slot die and passing the second water-soluble resin solution through a second slot of the multi-slot die, The process according to any one of claims 56 to 74, wherein the die angle (∠XYZ) is in the range of about 40° to about 90°, or about 45° to about 75°, or about 45° to about 55°, or about 46° to about 50°.

76. The process according to claim 75, wherein the die includes a die lip, and the distance (X1) between the die lip and the surface of the substrate is in the range of about 0.038 cm to about 0.127 cm, or about 0.064 cm to about 0.0762 cm.

77. A multilayer water-soluble film prepared by the process according to any one of claims 56 to 76.

78. The water-soluble film according to claim 77, wherein each layer of the film comprises a resin selected from the group consisting of polyvinyl alcohol homopolymers, polyvinyl alcohol copolymers, and combinations thereof.

79. A water-soluble film comprising a first layer and a second layer in contact with each other, wherein the first layer comprises a first water-soluble resin comprising a methacrylate-modified polyvinyl alcohol copolymer, and the second layer comprises a second water-soluble resin comprising a blend of a maleic acid-modified polyvinyl alcohol copolymer and a monomethyl maleate-modified polyvinyl alcohol copolymer, wherein the first layer and the second layer are present in a ratio of about 1:200 to about 1:1, or about 1:100 to about 1:3, or about 1:20 to about 1:5, respectively, based on the total weight of the water-soluble film, wherein the first layer comprises a first surface forming the outer surface of the film, wherein the film exhibits a haze % of less than about 50 when determined by a haze test, wherein the coefficient of static friction (COF) between a first portion of the outer surface of the film and a second portion of the outer surface of the film is less than about 2 when determined by a coefficient of friction test, wherein the first layer comprises a plasticizer, a blocking inhibitor, and a surfactant, and the second layer comprises a plasticizer and a surfactant, a water-soluble film.

80. A water-soluble film comprising a first layer and a second layer in contact with each other, wherein the first layer comprises a first water-soluble resin comprising a blend of a monomethyl maleate-modified polyvinyl alcohol copolymer and a polyvinyl alcohol homopolymer, and the second layer comprises a blend of a polyvinyl alcohol homopolymer, wherein the first layer and the second layer are present in a ratio of about 1:200 to about 1:1, or about 1:100 to about 1:3, or about 1:20 to about 1:5, respectively, based on the total weight of the water-soluble film, When the film is measured by a water vapor transmission rate test, it shows an MVTR of less than 25 gH 2 O / m 2 / day, wherein the film exhibits a heat seal strength of at least 15 N when measured by a heat seal strength test, a water-soluble film.

81. A water-soluble film comprising a first layer and a second layer in contact with each other, The first layer comprises a first water-soluble resin comprising (a) a polyvinyl alcohol homopolymer, a polyvinyl alcohol copolymer, or a mixture thereof, and (b) hydroxypropyl methylcellulose, and the second layer comprises a polyvinyl alcohol copolymer. A water-soluble film in which the first layer and the second layer are present in a ratio of about 1:200 to about 1:1, or about 1:100 to about 1:3, or about 1:20 to about 1:5, respectively, based on the total weight of the water-soluble film. Claim 82 The water-soluble film according to claim 81, wherein the polyvinyl alcohol copolymer in the second layer is an acrylate-modified polyvinyl alcohol copolymer. Claim 83 The water-soluble film according to claim 1, wherein the first layer comprises a foamed film layer having a co-gas fraction of at least about 5% by volume, or at least about 10% by volume, or at least about 20% by volume, or at least about 30% by volume, based on the volume of the first layer. Claim 84 The process according to claim 56, wherein the first layer comprises a foamed film layer.

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