Patent Description:
Water-soluble films are well known in the art. Water-soluble films have many applications, including non-edible forms, such as packaging materials, and edible forms, wherein the film itself is or makes up an edible article. Edible films are known for uses such as delivery of therapeutic agents, breath freshening agents, and flavors. <CIT> or <CIT> disclose transparent water soluble films comprising polyvinyl alcohol as resin.

When a food ingredient is provided in a traditional packaged state, the package must be torn or otherwise opened to remove the contents prior to cooking or eating. This is not only troublesome, but also has the disadvantage that the contents can tend to be spilled at the time of opening the packages, especially when they are in powder or liquid form. One solution is to package such contents with an edible film. If the packaging material is soluble in water, the package can be dissolved simply by pouring water over it or immersing it in the water, thus making it unnecessary to tear the package. Accordingly, it is highly desirable to package food contents with such a film.

Various edible water-soluble films known in the art have one or more deficiencies, including that they are not easily converted into packets or pouches, or they are particularly tough, or they are cold water soluble only. Therefore, these films cannot be used in applications that would require hot water to be added directly to the package, such as packaging for oatmeal, cocoa, or soup mixes. Additionally, it is known in the art that water-soluble films that contain a high level of sugar alcohols are often not transparent due to crystallization of or bleeding out of the sugar alcohol. In food packaging applications, it would be advantageous to package food contents in a water-soluble film that could dissolve in either hot or cold water and maintain transparency.

In a first aspect the claimed invention provides a water-soluble film, as defined in claim <NUM>. The water-soluble film comprises a water-soluble mixture of a water-soluble resin comprising polyvinyl alcohol and having a weight average molecular weight of <NUM>,<NUM> to <NUM>,<NUM>; a compatibilizing agent that is carboxymethyl cellulose; and a sugar alcohol plasticizer that is a solid at room temperature. The sugar alcohol plasticizer comprises xylitol and a second sugar alcohol plasticizer that is a solid at room temperature. The water-soluble resin is present in an amount in a range of 35wt% to 90wt% based on the total weight of the film. The ratio of compatibilizing agent to sugar alcohol present in the water-soluble film is from <NUM>:<NUM> to <NUM>:<NUM>, or the ratio of compatibilizing agent to xylitol is about <NUM>:<NUM>. The water-soluble film is transparent, such that when cast to a thickness of <NUM> and after storing for <NUM> days it has a measured opacity of <NUM>% or less, as determined by an X-RITE SP60 Series Sphere Spectrophotometer X-<NUM> colorimeter. When the water-soluble film is <NUM> (<NUM> mils) thick it completely dissolves in less than <NUM> seconds in water at <NUM>.

Also provided in a second aspect is an article, as defined in claim <NUM>. The article comprises a water-soluble packet comprising a film according to the first aspect.

Optionally, the water-soluble films of the invention can be thermoformed into a pouch.

Further aspects and advantages will be apparent to those of ordinary skill in the art from a review of the following detailed description. The description hereafter includes specific embodiments with the understanding that the disclosure is illustrative, and is not intended to limit the invention to the specific embodiments described herein. The scope of protection is defined by the claims.

Disclosed herein are water-soluble films comprising a water-soluble mixture of a first water-soluble polymer, a polymer compatibilizer (for example a cellulose ether polymer or a modified starch), and a sugar alcohol plasticizer that is a solid at room temperature. In the claimed invention, the water-soluble film comprises a water-soluble mixture of a water-soluble resin comprising polyvinyl alcohol and having a weight average molecular weight of <NUM>,<NUM> to <NUM>,<NUM>; a compatibilizing agent that is carboxymethyl cellulose; and a sugar alcohol plasticizer that is a solid at room temperature, where the sugar alcohol plasticizer comprises xylitol and a second sugar alcohol plasticizer that is a solid at room temperature. Optionally, the water-soluble films are edible. The water-soluble films of one aspect of the disclosure can be particularly advantageous in that they can be designed such that the transparency of the water-soluble film is maintained for long periods of time. The water-soluble films of the disclosure herein can have one or more other, optional advantages including thermoformability (e.g., into packets) and suitable toughness for use as packaging materials. For example, optional edible embodiments can be designed according to the disclosure herein to have suitable robustness, e.g. for use as packaging. In particular, water-soluble films according to one class of embodiments of the disclosure can demonstrate unexpectedly advantageous tear strength and further optionally an unexpectedly advantageous solubility.

As used herein, the term "comprising" indicates the potential inclusion of other agents, elements, steps, or features, in addition to those specified.

As used herein and unless specified otherwise all measurements of PVOH viscosity in centipoise (cP) are of a <NUM>% solution at <NUM>, and all measurements of carboxymethyl cellulose viscosity are of a <NUM>% solution at <NUM>.

As used herein, "substantial transparency" refers to a water-soluble film that, when cast to a thickness of about <NUM>, has a measured opacity of about <NUM>% or less, as determined by an X-RITE SP60 Series Sphere Spectrophotometer X-<NUM> colorimeter as described herein, or substantial equivalent, after storing for at least <NUM> days.

As used herein, "Δ% opacity" refers to the change in opacity, as determined by an X-RITE SP60 Series Sphere Spectrophotometer X-<NUM> colorimeter as described herein, or substantial equivalent, between the opacity of a film at t=<NUM> after film forming, and the opacity of the same film after conditioning and storage.

As used herein, "enhanced transparency" refers to a water-soluble film according to the disclosure herein that, when cast to a thickness of about <NUM> mils, demonstrates an opacity of <NUM>% or less, as determined by an X-RITE SP60 Series Sphere Spectrophotometer X-<NUM> colorimeter as described herein, or substantially equivalent, optionally after storing for at least <NUM> days.

As used herein, "favorable solubility" refers to a film according to the disclosure herein that, at about <NUM> mils thick, completely dissolves in less than <NUM> seconds, preferably less than <NUM> and most preferably less than <NUM> seconds in water at <NUM>.

As used herein, "good tear strength" refers to a tear strength of at least <NUM>/mil at <NUM> as measured by an Elmdorf Tearing Tester model number <NUM>, or equivalent.

As used herein and unless specified otherwise, the terms "wt. %" and "wt%" are intended to refer to the composition of the identified element in "dry" (non water) parts by weight of the entire film (when applicable) or parts by weight of the entire composition enclosed within a pouch (when applicable). As used herein and unless specified otherwise, the term "phr" is intended to refer to the composition of the identified element in parts per one hundred parts water-soluble PVOH resins.

Water-soluble films, optional ingredients for use therein, and methods of making the same are well known in the art. In the claimed invention, the water-soluble film includes polyvinyl alcohol (PVOH). PVOH is a synthetic resin generally prepared by the alcoholysis, usually termed hydrolysis or saponification, of polyvinyl acetate. Fully hydrolyzed PVOH, wherein virtually all the acetate groups have been converted to alcohol groups, is a strongly hydrogen-bonded, highly crystalline polymer which dissolves only in hot water -- greater than about <NUM> °F (<NUM>). If a sufficient number of acetate groups are allowed to remain after the hydrolysis of polyvinyl acetate, the PVOH polymer then being known as partially hydrolyzed, it is more weakly hydrogen-bonded and less crystalline and is soluble in cold water -- less than about <NUM> ° F (<NUM> ° C). An intermediate cold/hot water soluble film can include, for example, intermediate partially-hydrolyzed PVOH (e.g., with degrees of hydrolysis of about <NUM>% to about <NUM>%), and is readily soluble only in warm water- e.g., rapid dissolution at temperatures of about <NUM> and greater. Both fully and partially hydrolyzed PVOH types are commonly referred to as PVOH homopolymers although the partially hydrolyzed type is technically a vinyl alcohol-vinyl acetate copolymer.

The degree of hydrolysis (DH) of the PVOH included in the water-soluble films of the present disclosure can be about <NUM>% to about <NUM>%. As the degree of hydrolysis is reduced, a film made from the resin will have reduced mechanical strength but faster solubility at temperatures below about <NUM>. As the degree of hydrolysis increases, a film made from the resin will tend to be mechanically stronger and the thermoformability will tend to decrease. The degree of hydrolysis of the PVOH can be chosen such that the water-solubility of the resin is temperature dependent, and thus the solubility of a film made from the resin, compatibilizer polymer, and additional ingredients is also influenced. In the claimed invention, when the water-soluble film is <NUM> (<NUM> mils) thick it completely dissolves in less than <NUM> seconds in water at <NUM> In one class of embodiments the film is cold water-soluble. A cold water-soluble film, soluble in water at a temperature of less than <NUM>, can include PVOH with a degree of hydrolysis in a range of about <NUM>% to about <NUM>%, or in a range of about <NUM>% to about <NUM>%, or in a range of about <NUM>% to about <NUM>%. In another class of embodiments the film is hot water-soluble. For example, a hot water-soluble film is advantageous for edible applications such as water-soluble packets enclosing a hot food item, e.g. oatmeal, cocoa, or soup mix. A hot water-soluble film, soluble in water at a temperature of at least about <NUM>, can include PVOH with a degree of hydrolysis of at least about <NUM>%.

Other film-forming, water soluble resins for use in addition to PVOH can include, but are not limited to modified polyvinyl alcohols, polyacrylates, water-soluble acrylate copolymers, polyvinyl pyrrolidone, pullulan, water-soluble natural polymers including, but not limited to, guar gum, xanthan gum, carrageenan, and starch, water-soluble polymer derivatives including, but not limited to, ethoxylated starch and hydroxypropylated starch, copolymers of the forgoing and combinations of any of the foregoing.

In the claimed invention, the water-soluble resin is present in an amount in a range of 35wt% to 90wt% based on the total weight of the film. The weight ratio of the amount of the water-soluble polymer as compared to the combined amount of all plasticizers, compatibilizing agents, and secondary additives can be in a range of about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to <NUM>, or about <NUM> to <NUM>, for example.

Water-soluble polymers for use in the films described herein (including, but not limited to PVOH polymers) can be characterized by a viscosity in a range of about <NUM> to about <NUM> cP, or about <NUM> cP to about <NUM> cP, or about <NUM> to about <NUM> cP. The viscosity of a PVOH polymer is determined by measuring a freshly made solution using a Brookfield LV type viscometer with UL adapter as described in British Standard EN ISO <NUM>-<NUM>:<NUM> Annex E Brookfield Test method. It is international practice to state the viscosity of <NUM>% aqueous polyvinyl alcohol solutions at <NUM>. All viscosities specified herein in cP should be understood to refer to the viscosity of <NUM>% aqueous polyvinyl alcohol solution at <NUM>, unless specified otherwise.

It is well known in the art that the viscosity of a PVOH polymer is correlated with the weight average molecular weight (Mw) of the same PVOH polymer, and often the viscosity is used as a proxy for Mw. Thus, the weight average molecular weight of the water-soluble polymer can be in a range of about <NUM>,<NUM> to about <NUM>,<NUM>, or about <NUM>,<NUM> to about <NUM>,<NUM>, or about <NUM>,<NUM> to about <NUM>,<NUM>.

In the claimed invention, the molecular weight of the water-soluble polymer comprising polyvinyl alcohol is in the range of <NUM>,<NUM> to <NUM>,<NUM>. Unexpectedly, a water-soluble film according to the disclosure comprising polymers with molecular weights in the range of about <NUM>,<NUM> to about <NUM>,<NUM>, demonstrate enhanced transparency properties. If the molecular weight of the water-soluble polymer is too high, the resulting water-soluble film does not maintain substantial transparency.

In one type of embodiment, a water-soluble film including a mixture of PVOH (e.g., about <NUM>% hydrolyzed) having a <NUM>% solution viscosity of about <NUM> cps and <NUM> phr of sorbitol can demonstrate substantial transparency for <NUM> days. In contrast, a water-soluble film including a mixture of PVOH (about <NUM>% hydrolyzed) having a viscosity of <NUM> cps and <NUM> phr of sorbitol demonstrates substantial transparency for only <NUM> days.

Water-soluble films of the present disclosure include a compatibilizing agent for the sugar alcohol plasticizer that is a solid at room temperature. In the claimed invention the compatibilizing agent is carboxymethyl cellulose, and the ratio of compatibilizing agent to sugar alcohol present in the water-soluble film is from <NUM>:<NUM> to <NUM>:<NUM>, or the ratio of compatibilizing agent to xylitol is about <NUM>:<NUM>. As used herein, a "compatibilizing agent" is a component that when included in the water-soluble film in a range of about <NUM> phr to about <NUM> phr (a ratio of about <NUM>:<NUM> to about <NUM>:<NUM> to the sugar alcohol plasticizer that is a solid at room temperature), results in the water-soluble film maintaining transparency at a sugar alcohol loading that would otherwise cause the water-soluble film to lose transparency. For example, a water-soluble film including a compatibilizing agent is able to maintain a Δ% opacity of <NUM>% or less for a longer time period than an otherwise identical film that does not include the compatibilizing agent. The compatibilizing agent can be included in the water-soluble films of the present disclosure in a range of about <NUM> phr to about <NUM> phr, or in a range of about <NUM> phr to about <NUM> phr, or in a range of about <NUM> phr to about <NUM> phr. As the amount of compatibilizing agent included in the water-soluble film is reduced, the water-soluble film tends to lose transparency. As the amount of compatibilizing agent included in the water-soluble film is increased, the water-soluble film becomes more brittle and has slower dissolution times.

In one class of embodiments, the compatibilizer comprises sodium carboxymethyl cellulose (CMC). The degree of substitution of the CMC can be from about <NUM> to about <NUM>, for example. As used herein, "degree of substitution" refers to the number of hydroxyl groups that have been substituted with a sodium carboxymethyl group (CH<NUM>COO(Na)) per monomer unit. In one type of embodiment, the viscosity of a <NUM>% aqueous solution of CMC is in a range of about <NUM> to about <NUM> cP, as measured at <NUM> on a Brookfield LVT viscometer.

Water-soluble films according to the present disclosure further include sugar alcohol plasticizers that are solids at room temperature, wherein the sugar alcohol plasticizer comprises xylitol and a second sugar alcohol plasticizer that is a solid at room temperature. Sugar alcohol plasticizers that are solid at room temperature include, but are not limited to, isomalt, maltitol, sorbitol, xylitol, erythritol, adonitol, dulcitol, pentaerythritol, mannitol and combinations thereof. Suitable sugar alcohols are available from Rochem Intl. (Ronkonkoma, NY), Roquette (Lestrem, France), and Sigma-Aldrich Co, LLC (St. Louis, MO).

Sugar alcohol plasticizers that are solid at room temperature can be included in the water-soluble films of the present disclosure in an amount in a range of about <NUM> phr to about <NUM> phr, or about <NUM> phr to about <NUM> phr, or about <NUM> phr to about <NUM> phr, or about <NUM> phr to about <NUM> phr, for example <NUM> phr, <NUM> phr, <NUM> phr, <NUM> phr, or <NUM> phr. A sugar alcohol plasticizer that is a solid at room temperature is present in the water-soluble films of the present disclosure in an amount such that the ratio of compatibilizing agent to sugar alcohol plasticizer that is a solid at room temperature is in a range of <NUM>:<NUM> to <NUM>:<NUM>, for example about <NUM>:<NUM>, about <NUM>:<NUM>, about <NUM>:<NUM>, about <NUM>:<NUM>, about <NUM>:<NUM>, about <NUM>:<NUM>, about <NUM>:<NUM>, about <NUM>:<NUM>, about <NUM>:<NUM>, about <NUM>:<NUM>, about <NUM>:<NUM>, about <NUM>:<NUM>, about <NUM>:<NUM>, about <NUM>:<NUM>, about <NUM>:<NUM> and/or about <NUM>:<NUM>. Alternatively, the ratio of compatibilizing agent to xylitol is about <NUM>:<NUM>. As the amount of sugar alcohol included in the water-soluble film increases, the transparency of the water-soluble film becomes more negatively affected. As the amount of sugar alcohol included in the water-soluble film is reduced, the solubility of the water-soluble film becomes negatively affected. That is, for example, at a constant temperature a film of equal thickness will take longer to dissolve.

In the claimed invention, the sugar alcohol plasticizer that is a solid at room temperature comprises two or more sugar alcohol plasticizers that are solids at room temperature. Specifically, the sugar alcohol plasticizer comprises xylitol and a second sugar alcohol plasticizer that is a solid at room temperature. The two or more sugar alcohol plasticizers can be included in the film composition in any relative amounts. For example, the two or more sugar alcohol plasticizers can be included in the film composition in equal amounts, or one of the sugar alcohol plasticizers that is a solid at room temperature can be a minor impurity in another sugar alcohol plasticizer as provided by a commercial supplier. In another type of embodiment, the sugar alcohol plasticizer that is a solid at room temperature will include one that has a relatively high heat of fusion (e.g. above <NUM> J/g, or above192 J/g) and a second one that has a relatively low heat of fusion (e.g. <NUM> J/g or less, or <NUM> J/g or less, respectively).

In one class of disclosed embodiments, the sugar alcohol plasticizer that is a solid at room temperature is selected from the group consisting of isomalt, maltitol, sorbitol, xylitol, adonitol, mannitol, and combinations thereof, and further optionally the ratio of compatibilizing agent to sugar alcohol present in the water-soluble film is about <NUM>:<NUM>. As described below, water-soluble film according to this class of embodiments (including the described ratio of compatibilizing agent to sugar alcohol), cast to about <NUM> mils thick, maintained a Δ% opacity of <NUM>% or less for at least <NUM> days longer than water-soluble films of a similar composition except with no compatibilizing agent included, or at least <NUM> days longer, or at least <NUM> days longer. In the claimed invention, the sugar alcohol plasticizer comprises xylitol and a second sugar alcohol plasticizer that is a solid at room temperature.

In another class of disclosed embodiments, the sugar alcohol plasticizer that is a solid at room temperature is selected from the group consisting of isomalt, maltitol, sorbitol, xylitol, adonitol, and combinations thereof, and further optionally the ratio of compatibilizing agent to sugar alcohol present in the water-soluble film is less than <NUM>:<NUM>. Water-soluble films according to this class of embodiments (including the described ratio of compatibilizing agent to sugar alcohol), cast to about <NUM> mils thick, were shown to maintain a Δ% opacity of <NUM>% or less for at least <NUM> days longer than water-soluble films of a similar composition except with no CMC included, or at least <NUM> days longer, or at least <NUM> days longer, or at least <NUM> days longer. In the claimed invention, the sugar alcohol plasticizer comprises xylitol and a second sugar alcohol plasticizer that is a solid at room temperature.

Unexpectedly, there was found to be no correlation between the number of carbons, molecular weight, or structure (linear vs cyclic or structural isomers) of the sugar alcohol and the compatibilization of the sugar alcohol by the compatibilizing agent. That is, the transparency enhancement of the water-soluble films that include the compatibilizing agent could not be predicted based on the number of carbons, molecular weight, or structure (linear vs. cyclic or structural isomers) of the sugar alcohol. As mentioned above, "enhanced transparency" as used herein refers to a water-soluble film that demonstrates an opacity of <NUM>% or less as measured by a spectrophotometer, for example, <NUM>% or less, or <NUM>% or less. Unacceptable amounts of cloudiness of the water-soluble film results when a water-soluble film has an opacity of <NUM>% or more, <NUM>% or more, or <NUM>% or more. More unexpectedly, the ability of a given compatibilizing agent/sugar alcohol combination to result in a water-soluble film with enhanced transparency (relative to a film with the same sugar alcohol and no compatibilizing agent) can be predicted based on the heat of fusion of the sugar alcohol. In one class of embodiments enhanced transparency is demonstrated when a sugar alcohol plasticizer that is a solid at room temperature characterized by a heat of fusion of about <NUM> J/g or less is included in a water-soluble film in an amount of about <NUM> phr or less, with a compatibilizing agent. Suitable sugar alcohol plasticizers that demonstrate enhanced transparency when included in a water-soluble film with a compatibilizing agent in an amount of about <NUM> phr or less can include, consist essentially of, or can consist of one or more of isomalt, maltitol, sorbitol, adonitol, and xylitol, and combinations thereof. For example, it was shown that a water-soluble film comprising <NUM> phr of xylitol, having a heat of fusion of <NUM> J/g, demonstrated an opacity of <NUM> after <NUM> days. In contrast, a water-soluble film comprising <NUM> phr of pentaerythritol, having a heat of fusion of <NUM> J/g, demonstrated an opacity of <NUM> after <NUM> days and had an undesirable cloudiness. In another, non-exclusive class of embodiments enhanced transparency is demonstrated when a sugar alcohol plasticizer that is a solid at room temperature characterized by a heat of fusion of about <NUM> J/g or less and has at least two adjacent, non sterically hindered hydroxyl groups in a common plane is included in a water soluble film in an amount of about <NUM> phr or less. Without intending to be bound by theory, it is believed that the at least two sterically unhindered adjacent hydroxyl groups in a common plane favors the hydrogen bonding of the hydroxyls of the sugar alcohol with the hydroxyls of PVOH. Further, without intending to be bound by theory, it is believed that the hydrogen bonding interactions of the sugar alcohol with the PVOH stabilizes the sugar alcohols in the film formulation, allowing for a greater loading of the sugar alcohols characterized by a heat of fusion of <NUM> J/g or less. In another class of embodiments, enhanced transparency is demonstrated when a sugar alcohol plasticizer that is a solid at room temperature characterized by a heat of fusion of about <NUM> J/g or less is included in a water-soluble film in an amount of about <NUM> phr to about <NUM> phr, or about <NUM> phr, with a compatibilizing agent. Suitable sugar alcohol plasticizers that demonstrate enhanced transparency when included in a water-soluble film with a compatibilizing agent in an amount of about <NUM> phr to about <NUM> phr , or about <NUM> phr include, but are not limited to, isomalt, sorbitol, and combinations thereof. For example, it was shown that a water-soluble film comprising <NUM> phr of sorbitol, having a heat of fusion of <NUM> J/g demonstrated an opacity of <NUM> after <NUM> days. In contrast, a water-soluble film comprising <NUM> phr of adonitol, having a heat of fusion of <NUM> J/g, had an opacity of <NUM> after <NUM> days and had an undesirable cloudy appearance. In another, non-exclusive class of embodiments enhanced transparency is demonstrated when a sugar alcohol plasticizer that is a solid at room temperature characterized by a heat of fusion of about <NUM> J/g or less and has at least two adjacent, non sterically hindered hydroxyl groups in a common plane is included in a water soluble film in an amount of about <NUM> phr to about <NUM> phr, for example <NUM> phr. Without intending to be bound by theory, it is believed that the at least two sterically unhindered adjacent hydroxyl groups in a common plane favors the hydrogen bonding of the hydroxyls of the sugar alcohol with the hydroxyls of PVOH. Further, without intending to be bound by theory, it is believed that the hydrogen bonding interactions of the sugar alcohol with the PVOH stabilizes the sugar alcohols in the film formulation, allowing for a greater loading of the sugar alcohols characterized by a heat of fusion of <NUM> J/g or less.

In one class of embodiments, the water-soluble film includes a mixture of PVOH, CMC, xylitol, and sorbitol. The CMC to xylitol ratio can be <NUM>:<NUM>, for example, while the ratio of compatibilizing agent to total sugar alcohol plasticizer that is a solid at room temperature is in the range of about <NUM>:<NUM> to <NUM>:<NUM>. Unexpectedly, a water-soluble film comprising a <NUM>:<NUM> CMC to xylitol ratio demonstrated both favorable solubility and good tear strength. As described above, when used herein, "favorable solubility" refers to a film that, at about <NUM> mils thick, completely dissolves in less than <NUM> seconds, preferably less than <NUM> and most preferably less than <NUM> seconds in water at <NUM>. As used herein, "good tear strength" refers to a tear strength of at least <NUM>/mil as measured by an Elmdorf Tearing Tester model number <NUM>, or equivalent as described in the Tear Strength Measurements section below. Surprisingly, a water-soluble film including a <NUM>:<NUM> ratio of CMC to xylitol had a faster rate of dissolution than a water-soluble film including a CMC to xylitol ratio in which the xylitol is the major component. The rate of dissolution of the water-soluble film including a <NUM>:<NUM> ratio of CMC to xylitol was also comparable to the rate at which a water soluble film of the same composition, except with no CMC, dissolves. The rate of dissolution of a water-soluble film comprising CMC and xylitol would be expected to decrease when the amount of CMC in the water-soluble film increased because CMC has a slower rate of dissolution than xylitol.

More unexpectedly, a water-soluble film comprising a <NUM>:<NUM> ratio of CMC to xylitol demonstrates an increase in tear strength relative to a water-soluble film comprising either CMC or xylitol alone. Both CMC and xylitol are known to independently reduce the tear strength of water-soluble films comprised of PVOH. The inclusion of both components in a water-soluble film would be expected to compound the individual effects, reducing the tear strength of a PVOH based water soluble film comprising to a level between the PVOH tear strength of a water-soluble film with CMC only and the PVOH tear strength of a water-soluble film with only xylitol.

The water-soluble films according to the present disclosure may include other optional additive ingredients including, but not limited to, plasticizers that are liquids at room temperature, surfactants, film formers, antiblocking agents, internal release agents and other functional ingredients, for example in amounts suitable for their intended purpose.

Water is recognized as a very efficient plasticizer for PVOH and other polymers; however, the volatility of water makes its utility limited since polymer films need to have at least some resistance (robustness) to a variety of ambient conditions including low and high relative humidity. Glycerin is much less volatile than water and has been well established as an effective plasticizer for PVOH and other polymers. Glycerin or other such liquid plasticizers by themselves can cause surface "sweating" and greasiness if the level used in the film formulation is too high. This can lead to problems in a film such as unacceptable feel to the hand of the consumer and even blocking of the film on the roll or in stacks of sheets if the sweating is not mitigated in some manner, such as powdering of the surface. This could be characterized as over plasticization. However, if too little plasticizer is added to the film the film may lack sufficient ductility and flexibility for many end uses, for example to be converted into a final use format such as pouches.

Plasticizers that are liquids at room temperature for use in water-soluble films of the present disclosure include, but are not limited to, glycerol, diglycerol, propylene glycol, ethylene glycol, diethyleneglycol, triethylene glycol, tetraethyleneglycol, polyethylene glycols up to MW <NUM>, <NUM> methyl <NUM>, <NUM> propane diol, lactic acid and combinations thereof. As less plasticizer is used, the film becomes more brittle, whereas as more plasticizer is used the film loses tensile strength. Plasticizers that are liquids at room temperature can be included in the water-soluble films in an amount in a range of about <NUM> phr to about <NUM> phr, or from about <NUM> phr to about <NUM> phr, or from about <NUM> phr to about <NUM> phr, for example.

Surfactants for use in water-soluble films are well known in the art. Optionally, surfactants are included to aid in the dispersion of the polymer solution upon casting. Suitable surfactants for water-soluble films of the present disclosure include, but are not limited to, dioctyl sodium sulfosuccinate, lactylated fatty acid esters of glycerol and propylene glycol, lactylic esters of fatty acids, sodium alkyl sulfates, polysorbate <NUM>, polysorbate <NUM>, polysorbate <NUM>, polysorbate <NUM>, lecithin, acetylated fatty acid esters of glycerol and propylene glycol, and acetylated esters of fatty acids, and combinations thereof. Thus, surfactants can be included in the water-soluble films in an amount of less than about <NUM> phr, for example less than about <NUM> phr, or less than about <NUM> phr, for example.

A class of embodiments of the water-soluble films according to the present disclosure is characterized by the water-soluble film being edible. In this class of disclosed embodiments the water-soluble polymers can include, can consist essentially of, or can consist of one or more of PVOH, modified PVOH, water-soluble natural polymers including, but not limited to, guar gum, xanthan gum, carrageenan, and starch, water-soluble polymer derivatives including, but not limited to, ethoxylated starch and hydroxypropylated starch, copolymers of the forgoing, and combinations of the forgoing. In the claimed invention, the water-soluble film comprises a water-soluble mixture of a water-soluble resin comprising polyvinyl alcohol. In one class of edible embodiments, the water-soluble polymer is included in the film composition in the lowest amount possible that will still allow the resulting film to demonstrate acceptable tear strength, solubility, tensile strength, elongation at break, and energy to break. Optional ingredients for inclusion in water-soluble films according to the disclosure include one or more of plasticizers that are liquid at room temperature, surfactants, compatibilizers, co-polymers, and co-film formers, for example. Liquid plasticizers can include, consist essentially of, or consist of one or more of glycerol, diglycerol, propylene glycol, low molecular weight polyethylene glycol (e.g., having a liquid consistency, for example having a molecular weight such as <NUM>, <NUM>, and <NUM>), monoacetin, triacetin, triethyl citrate, and <NUM>,<NUM>-butanediol. Surfactants can include, consist essentially of, or consist of dioctyl sodium sulfosuccinate, lactylated fatty acid esters of glycerol and propylene glycol, lactylic esters of fatty acids, sodium alkyl sulfates, polysorbate <NUM>, polysorbate <NUM>, polysorbate <NUM>, polysorbate <NUM>, lecithin, acetylated fatty acid esters of glycerol and propylene glycol, and acetylated esters of fatty acids, for example. Film formers can include, consist essentially of, or consist of one or more of pullulan, pectin, starch, gelatin, sodium alginates and modified starches. Other optional ingredients will be apparent to one of ordinary skill in the art in view of the present disclosure. Components for inclusion in edible water soluble films can be those designated as "Generally Recognized as Safe" (GRAS) by the United States Food and Drug Administration, and/or components with assigned, allowable E-numbers in the European Union, and/or components that are not yet designated as GRAS or E-numbered but have gone through proper testing and have been demonstrated as safe for human consumption in the amounts proposed for use in the film.

Water-soluble films according to the present disclosure can be designed by the disclosure herein to demonstrate excellent practical toughness. As used herein, "excellent practical toughness" refers to one or more of tensile strength, elongation at break, and energy to break values that fall within the ranges described herein, optionally a combination of all three of tensile strength, elongation at break, and energy to break values. Thus, according to this aspect of the invention the water-soluble films according to the present disclosure can have a tensile strength of at least about <NUM> N/mm<NUM>, or greater than about <NUM> N/mm<NUM>, or greater than about <NUM> N/mm<NUM>, or greater than about <NUM> N/mm<NUM> as measured on a Model <NUM> Instron® Tensile Tester, or equivalent, as described in the Tensile Strength Measurement section below. The water-soluble films according to this aspect of the invention can have an elongation at break value of at least about <NUM>%, or greater than about <NUM>%, or greater than about <NUM>%, or greater than about <NUM>% as measured on a Model <NUM> Instron® Tensile Tester, or equivalent, as described in the Tensile Strength Measurement section below. The water-soluble films according to this aspect of the invention can have an energy to break of at least about <NUM> J/mm<NUM>, or greater than about <NUM> J/mm<NUM>, or greater than about <NUM> J/mm<NUM> as measured on a Model <NUM> Instron® Tensile Tester, or equivalent, as described in the Tensile Strength Measurement section below. In one class of embodiments, a water-soluble film according to the disclosure includes PVOH, a CMC compatibilizing agent and a combination of xylitol and sorbitol as the sugar alcohol plasticizer that is a solid at room temperature, with a CMC to sugar alcohol plasticizer ratio of about <NUM>:<NUM>. Water-soluble films according to this embodiment demonstrate good dissolution time at <NUM>, for example about <NUM> seconds, good tensile strength, for example about <NUM> N/mm<NUM>, good elongation to break, for example about <NUM>%, and good energy to break, for example about <NUM> J/mm<NUM>. In another class of embodiments, a water-soluble film according to the disclosure includes PVOH, a modified starch compatibilizing agent and a combination of xylitol and sorbitol as the sugar alcohol plasticizer that is a solid at room temperature, with a compatibilizing agent to sugar alcohol plasticizer ratio of about <NUM>:<NUM>. Water-soluble films according to this embodiment demonstrate good dissolution time at <NUM>, for example about <NUM> seconds, good tensile strength, for example about <NUM> N/mm<NUM>, good elongation to break, for example about <NUM>%, and good energy to break, for example about <NUM> J/mm<NUM>.

The water-soluble films can be formed into a water-soluble packet. Packets may be made using any suitable equipment and method, including the various methods already commonly known in the art. The water-soluble film optionally can be drawn into a suitable mold. Heat can be applied to the water-soluble film during the process, to result in a process commonly known as thermoforming. Water-soluble films according to the present disclosure are heat sealable. As used herein, "heat sealable" refers to films that when heat sealed at a temperature in a range of about <NUM> °F to about <NUM> °F (<NUM> to about <NUM>) do not peel apart by hand without tearing the film and do not show any indications of degradation (i.e., browning or bubbling) when heat sealed in a TS-<NUM> Heat Sealer available from Lako Tool & Manufacturing, Inc of Perrysburg, OH, or equivalent, as described in the Heat Seal Measurements section below. In one class of embodiments, the heat sealable water-soluble films have a peak load ratio (i.e. a ratio of the seal peak load to the film peak load) of at least about <NUM>, at least about <NUM>, at least about <NUM>, or at least about <NUM> as determined by measurements taken on a Model <NUM> Instron® Tensile Tester, or equivalent, as described in the Tensile Strength Measurement section below. Water-soluble films according to the present disclosure are thermoformable. As used herein, "thermoformable" refers to a water soluble film that has an elongation at about <NUM> and <NUM>% relative humidity of at least about <NUM>%, or at least about <NUM>% and is heat stable.

Various sugar alcohols were added to polyvinyl alcohol formulations and cast at nominally <NUM> mil thicknesses to determine if the film turns cloudy. These experiments were performed with and without carboxymethyl cellulose (CMC). All film samples were hung in a lab environment set to operate at <NUM> +/- <NUM> (<NUM> °F +/- <NUM> °F) with an observed range of <NUM> - <NUM> (<NUM> °F-<NUM> °F). The relative humidity of the lab was set to <NUM>% +/- <NUM>% with an observed range of <NUM>% - <NUM>% RH (RH = relative humidity). Each film was observed every four days plus or minus a day for a two week minimum.

The films were tested for a change in the percent opacity by an X-RITE SP60 Series Sphere Spectrophotometer X-<NUM> colorimeter, available from X-Rite Incorporated, Grand Rapids, Michigan. The spectrophotometer was calibrated using X-Rite Calibration Standard SP62-<NUM> (L*<NUM>, a* -<NUM>, B* -<NUM>). A <NUM>" by <NUM>" square of Mylar (approximately <NUM> mil gauge) was cut and the average opacity was determined to be <NUM> by the spectrophotometer. Five <NUM>" by <NUM>" squares were drawn on the Mylar squares with a fine tip marker according to the drawings in <FIG>. Samples of film were fixed to the Mylar template using <NUM>/<NUM>" binder clips and the film samples were each labeled according to their identifying formula.

Non-powdered moisture barrier gloves were used when handling the film samples to mitigate moisture contamination of the film samples. Moisture contamination may cause unnatural cloudiness in the film. The films were cast to a nominal <NUM> mil gauge. The samples were cast in ambient conditions and initial data was measured in the ambient environment prior to placement in the testing environment of nominally <NUM> +/- <NUM> (<NUM> °F +/- <NUM> °F), and <NUM>% RH +/- <NUM>% RH. For conditioning of the film, the <NUM>/<NUM>" binder clips holding the test sample were clipped to a coat hanger using <NUM>-<NUM>/<NUM>" binder clips and hung from a the coat hanger in the specified conditioning environment. Film was mixed on a Monday, cast on a Tuesday, and hung in set environment on Wednesday (t=<NUM>). Film was measured every Monday, Wednesday, and Friday (t= <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) until <NUM> days of measurement and observation was achieved.

The colorimeter was set to: number of average readings N = <NUM>, Lab, SPIN, and illuminant of D65/<NUM>. The Opacity test was selected from the spectrophotometer menu. A double Mylar standard (two plies of <NUM> mil Mylar film over white portion of a Leneta chart <NUM>-<NUM>/<NUM>" X <NUM>¼" 2C B#<NUM>) was loaded into the spectrophotometer. For each of the five spots designated on the film sample swatch, a piece of Mylar film was selected for backing and clipped to the back of the sample being measured. The sample was placed over the black portion of the Leneta chart. When the sample was flat against the Leneta chart and the sample itself was flat between the front and back sheets of Mylar, two sample measurements were taken. The sample was moved to the white portion of the Leneta chart and when the sample was flat against the Leneta chart and flat between the two sheets of Mylar, two samples measurements were taken. A reading of the white portion of the Leneta chart, without the samples. For each measurement, the % Opacity, L, a, b, and E values that were displayed on the screen were recorded. After measurement, the samples were returned to the conditioning environment. The film opacity is reported as the number of days the Δ% Opacity was <NUM>% or less, i.e., the number of days the difference in opacity between the tested film and the t=<NUM> film was <NUM>% or less.

This method covers the determination of the average force in grams per mil of specimen thickness required to propagate tearing through a specified length of polyvinyl alcohol (PVOH) film. The force in grams required to propagate tearing across a film is measured using a precisely calibrated pendulum device. Acting by gravity, the pendulum swings through an arc, tearing the specimen from a pre-cut slit. The specimen is held stationary on one side and on the other is fixed to the pendulum. The loss of energy of the pendulum swing is indicated by a pointer on a scale. The scale indication is a function of the force required to tear the specimen. This method is of value in ranking relative tearing resistance of PVOH films. The water-soluble films were evaluated on an Elmendorf Tearing Tester Model # <NUM>, in accordance with MSTM 107RD Standard Test Method for Propagation Tear Resistance of Polyvinyl Alcohol Film.

Various sugar alcohols were added to polyvinyl alcohol formulations and cast at nominally <NUM> mil thicknesses. These experiments were performed with and without carboxymethyl cellulose (CMC). The water-soluble films were conditioned at a temperature of about <NUM> +/- <NUM> (<NUM> °F +/- <NUM> °F) and relative humidity of about <NUM>% ± <NUM>% for not less than <NUM> hours prior to the test. The tests were conducted in the standard laboratory atmosphere of a temperature of <NUM> +/- <NUM> (<NUM> °F +/- <NUM> °F) and a relative humidity of <NUM>% ± <NUM>%. The average tearing force in grams-force per MIL was calculated as follows: <MAT>.

Various sugar alcohols were added to polyvinyl alcohol formulations and cast at nominally <NUM> mil thicknesses. Test specimens were cut from film samples (i.e., about <NUM>×<NUM> specimen). If cut from a film web, specimen was cut from areas of web approximately evenly spaced along the transverse direction of the web. Each specimen was locked in a separate <NUM> slide mount.

For each specimen, a beaker was filled with <NUM> of distilled water. The water temperature was measured with a thermometer and, if necessary, heated or cooled to maintain temperature at <NUM> or <NUM>. The height of column of water was marked, and a magnetic stirring rod was added to the beaker. The stir speed was adjusted until a vortex approximately one-fifth the height of the water column developed. The depth of the vortex was marked.

The <NUM> slide mount was secured to a <NUM> slide mount holder such that the long end of the slide mount was parallel to the water surface. The depth adjuster of the holder was set so that when dropped, the end of the clamp was <NUM> below the surface of the water. One of the short sides of the slide mount was positioned next to the side of the beaker with the other positioned directly over the center of the stirring rod such that the film surface was perpendicular to the flow of the water.

In one motion, the secured slide was dropped and clamped into the water and the timer was started. Disintegration occurred when the film broke apart. When all visible film was released from the slide mount, the slide was raised out of the water while the solution was monitored for undissolved film fragments. Dissolution occurred when all film fragments were no longer visible and the solution became clear.

Various sugar alcohols were added to polyvinyl alcohol formulations and cast at nominally <NUM> mil thickness. Samples were about <NUM> inches (<NUM>) wide and about <NUM> inches (<NUM>) long with the long dimension in the machine (casting) direction. The tests were conducted in the standard laboratory atmosphere of a temperature of <NUM> +/- <NUM> (<NUM> °F +/- <NUM> °F) and a relative humidity of <NUM>% ± <NUM>%. The ultimate tensile strength was measured utilizing the ASTM D <NUM>, "Standard Test Method for Tensile Properties of Thin Plastic Sheeting. " The test was conducted on a Model <NUM> Instron® Tensile Tester in a laboratory after aging at least about <NUM> hours. Without intending to be bound by any particular theory, it is believed that the Instron® grips utilized in the test may affect the test results. Consequently, the test was conducted utilizing Instron® grips having model number <NUM>-<NUM> faces, which are rubber coated and <NUM> wide. Values were obtained directly from the Instron® Bluehill software version <NUM>.

Various sugar alcohols were added to polyvinyl alcohol formulations and cast at nominally <NUM> mil thickness. Samples were about <NUM> inches wide and at least about <NUM> inches long with the long dimension in the machine (casting) direction. The tests were conducted in the standard laboratory atmosphere of a temperature of <NUM> +/- <NUM> (<NUM> °F +/- <NUM> °F) and a relative humidity of <NUM>% ± <NUM>%. The elongation to break of a film was measured utilizing the ASTM D <NUM>, "Standard Test Method for Tensile Properties of Thin Plastic Sheeting. " The test was conducted on a Model <NUM> Instron® Tensile Tester in a laboratory conditioned after aging at least about <NUM> hours. Without intending to be bound by any particular theory, it is believed that the Instron® grips utilized in the test may affect the test results. Consequently, the test was conducted utilizing Instron® grips having model number <NUM>-<NUM> faces, which are rubber coated and <NUM> wide. Values were used directly from the Instron® Bluehill software version <NUM>.

Various sugar alcohols were added to polyvinyl alcohol formulations and cast at nominally <NUM> mil thickness. Samples were about <NUM> inches wide and about <NUM> inches long with the long dimension in the machine (casting) direction. The tests were conducted in the standard laboratory atmosphere of a temperature of <NUM> +/- <NUM> (<NUM> °F +/- <NUM> °F) and a relative humidity of <NUM>% ± <NUM>%. The energy to break of a film at was measured utilizing the ASTM D <NUM>, "Standard Test Method for Tensile Properties of Thin Plastic Sheeting. " The test was conducted on a Model <NUM> Instron® Tensile Tester in a laboratory after aging at least about <NUM> hours. Without intending to be bound by any particular theory, it is believed that the Instron® grips utilized in the test may affect the test results. Consequently, the test was conducted utilizing Instron® grips having model number <NUM>-<NUM> faces, which are rubber coated and <NUM> wide. Values were used directly from the Instron® Bluehill software version <NUM>. <NUM> for the Energy/Area methodology.

Various sugar alcohols were added to polyvinyl alcohol formulations and cast at nominally <NUM> mil thickness. Samples were about <NUM> inches (<NUM>) wide and about <NUM> inches (<NUM>) long with the long dimension in the machine (casting) direction. The tests were conducted in the standard laboratory atmosphere of a temperature of <NUM> +/- <NUM> (<NUM> °F +/- <NUM> °F) and a relative humidity of <NUM>% ± <NUM>%. The peak load for tensile mode failure for the samples was determined (i.e., the film peak load) on a Model <NUM> Instron® Tensile Tester. Samples were then heat sealed at a series of temperatures at <NUM> psi (<NUM> kPa) and a dwell time of <NUM> second in a TS-<NUM> Heat Sealer available from Lako Tool & Manufacturing, Inc of Perrysburg, OH. At temperatures below about <NUM> °F (<NUM>) the seals were found to peel apart without the film tearing during hand inspection. At temperatures above <NUM> °F (<NUM>) the films began to turn brown and bubbling occurred, indicating the onset of degradation. Therefore, a temperature ladder from <NUM> °F to <NUM> °F (<NUM> to <NUM>)in <NUM> °F (about <NUM>) increments was conducted. The sealed films for each temperature setting were then tested in the tensile mode on a Model <NUM> Instron® Tensile Tester and the seal peak load was recorded. The ratio of the seal peak load divided by the film peak load was reported as the peak load ratio.

A set of water-soluble films were prepared with the ingredients identified below in the amounts shown (phr).

Water-soluble films <NUM>-<NUM> were each comprised of <NUM> wt% PVOH, based on the total weight of the film. <NUM> wt% of the films were comprised of a combination of CMC and xylitol. Water-soluble film <NUM> contained <NUM> wt% PVOH with no CMC or xylitol, as a control film. The relative amounts of CMC and xylitol were varied over films <NUM>-<NUM>. <NUM> mil thick water-soluble films were cast according to formulae <NUM>-<NUM>, conditioned for <NUM> hours, and were tested for tear strength, solubility, tensile strength, elongation at break, and energy to break, as described above. The results are reproduced in the table below.

<FIG> is a plot of the tear strengths vs. the wt% xylitol included in the water-soluble films. <FIG> is a plot of dissolution times vs. the wt% xylitol included in the water-soluble films. <FIG> is a contour plot of the tear strengths of PVOH based water-soluble films with different loadings of CMC and xylitol. As expected, the water-soluble film containing PVOH and CMC with no xylitol, film <NUM>, was found to be brittle and dissolve relatively slowly at <NUM>, relative to the control film <NUM>. This film did show some improved dissolution properties at <NUM>. Film <NUM>, the other extreme, containing PVOH and xylitol with no CMC also was found to have decreased tear strength relative to the control film <NUM>, and increased rate of dissolution, as expected. Unexpectedly, when the CMC and xylitol were both included, in a ratio of about <NUM>:<NUM> respectively (film <NUM>), the tear strength was found to be higher than the tear strength of either film <NUM> or film <NUM>; however as expected, the tear strength was still less than that of the control film <NUM>. Also surprisingly, film <NUM> had the fastest rate of dissolution out of all the films except the xylitol-only film (film <NUM>), which had similar rates of dissolution. This is unexpected because in film <NUM>, CMC is the major component of the CMC/xylitol mixture, and the rate of dissolution would be expected to decrease, that is a film of given thickness would be expected to take longer to dissolve with the higher level of CMC.

<NUM> mil thick water-soluble films were cast according to formulae <NUM> and <NUM>, were conditioned for <NUM> hours, and the transparency behavior of the water-soluble films was monitored. The water-soluble film containing the low molecular weight polyvinyl alcohol, film <NUM>, maintained a Δ% Opacity of <NUM>% or less for less than <NUM> days. In contrast, the water-soluble film containing the high molecular weight polyvinyl alcohol, film <NUM>, only maintained a Δ% Opacity of <NUM>% or less for less than <NUM> days.

<NUM> mil thick water-soluble films were cast according to formulae <NUM>-<NUM>, conditioned for <NUM> hours, and the transparency behavior of the water-soluble films was monitored. The number of days until a film had a Δ% Opacity of greater than <NUM>% was recorded. The results are reproduced in the table below.

The water-soluble films that contained CMC, films <NUM>, <NUM> and <NUM> maintained substantial transparency for at least <NUM> days. However, films <NUM>, <NUM>, and <NUM> that did not contain CMC became more opaque quickly. As the loading of sorbitol increased the films without CMC became more opaque at increasingly faster rates. At a sorbitol loading of 10phr the film (film <NUM>) without CMC remained substantially transparent less than <NUM> days. At a sorbitol loading of <NUM> phr the film (film <NUM>) remained substantially transparent for less than <NUM> days, and when the sorbitol loading was increased further, to <NUM> phr, the film (film <NUM>) turned opaque much more quickly, after less than <NUM> days. When CMC was present in the films, the film containing <NUM> phr sorbitol (film <NUM>), the film containing <NUM> phr sorbitol (film <NUM>) and the film containing <NUM> phr sorbitol (film <NUM>) remained substantially transparent for at least <NUM> days. Water-soluble films that contained sorbitol demonstrated poor transparency without CMC at even low sorbitol loadings, and the performance was improved with the introduction of CMC into the film, especially at high sorbitol loadings.

The water-soluble films that contained <NUM>, phr of maltitol and no CMC, film <NUM>, remained substantially transparent for only <NUM> days. When the maltitol loading was increased further to <NUM> and <NUM> phr, films <NUM> and <NUM>, the films became opaque much more quickly, after less than <NUM> days. However, the films that contained CMC remained substantially transparent for up to <NUM> days when the maltitol loading was <NUM>, <NUM> days when the maltitol loading was <NUM> phr and <NUM> days when the maltitol loading was <NUM> phr. Although maltitol is a disaccharide consisting of a linear and a cyclic unit, films that included maltitol had similar transparency properties as films that included the linear monosaccharide, sorbitol. As in the case with sorbitol, Example <NUM>, the inclusion of CMC in the films that included maltitol resulted in an increase in the number of days that the films remained substantially transparent.

Mannitol, (2R,3R,4R,5R)-hexan-<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>-hexol, is a stereoisomer of sorbitol, (<NUM>,3R,4R,5R)-hexan-<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>-hexol. However, unlike the water-soluble films that included sorbitol (Example <NUM>), water-soluble films that included mannitol only remained substantially transparent for <NUM> days, regardless of the loading level of mannitol, or the inclusion of CMC. Although mannitol and sorbitol are both six carbon, linear sugars of equal molecular weight, the heats of fusion of the two sugar alcohol plasticizers that are solids at room temperature are not similar. Sorbitol has a heat of fusion of <NUM> J/g and mannitol has a heat of fusion of <NUM> J/g.

The water-soluble film that contained <NUM> phr of xylitol and no CMC, film <NUM>, remained substantially transparent for <NUM> days. When the xylitol loading was increased to <NUM> or <NUM> phr, films <NUM> and <NUM>, the films became opaque much more quickly, after <NUM> days. However, the films that included CMC were substantially transparent for up to <NUM> days, <NUM> days and <NUM> days at xylitol loadings of <NUM>, <NUM>, and <NUM> phr, respectively. Although xylitol is a five carbon sugar alcohol plasticizer, the water-soluble films that include xylitol behaved similar to the water-soluble films that contained the six carbon sugar alcohol plasticizer, sorbitol. As in the case with sorbitol, Example <NUM>, the inclusion of CMC in the films that included xylitol resulted in an increase in the number of days that the films remained substantially transparent.

An edible water-soluble film was prepared with the ingredients identified below in the amounts shown (phr).

<NUM> mil thick water-soluble films were cast according to formula <NUM>, conditioned for <NUM> hours, and were tested for tear strength, solubility, tensile strength, elongation at break, and energy to break as described above. The results are reproduced in the table below.

Example <NUM> demonstrates an edible water soluble film according to the invention that has good dissolution time, tensile strength, elongation at break and energy to break. Example <NUM> includes a cellulose ether as a compatibilizing agent.

Example <NUM>, like Example <NUM>, demonstrates an edible water soluble film according to the invention that has good dissolution time, tensile strength, elongation at break and energy to break. Example <NUM> includes a modified starch as a compatibilizing agent.

A water-soluble film was prepared with the ingredients identified below in the amounts shown (phr).

Water-soluble packets were made from the water-soluble film according to formula <NUM>. The water-soluble film of the packets had an average thickness of <NUM> mils. Oatmeal was enclosed within the packets. The compatibility of the packets with the oatmeal was tested under three test atmospheres for <NUM> days. The packets were inserted into high density polyethylene (HDPE) jars and capped, and subjected to one of either: ambient temperature and humidity (about <NUM> and about <NUM> to <NUM>% relative humidity (RH)); <NUM> and about <NUM>% RH; or <NUM> and about <NUM>% RH.

After <NUM> days, the exposed packets were tested against unexposed film of formula <NUM>. Inspection of the exposed packets revealed no visible film or product discoloration, or packet adhesiveness when stored in HDPE jars. Flexibility appeared unchanged. Solubility tests were conducted and no increased time was required for complete solubility as a result of product storage within test environments. The elongation values of the packets were tested against unexposed film. Under all test environments, the elongation values of the packets were slightly reduced when compared to the unexposed film. The results are reproduced in the table below.

<NUM> mil thick water-soluble films were cast according to formulae <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> - <NUM>, and <NUM>, conditioned for <NUM> hours, and the transparency behavior of the water-soluble films was monitored. The transparency of the films was monitored for <NUM> days with exception of erythritol (formula <NUM>), <NUM> days, and mannitol (formula <NUM>), <NUM> days. The results are reproduced in the table below.

Films according to formulae <NUM>, <NUM>, <NUM>, and <NUM> having the described amounts of dulcitol, erythritol, pentaerythritol or mannitol as the sugar alcohol plasticizer that is a solid at room temperature demonstrated an undesirable cloudiness. In contrast, films according to formulae <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> comprising isomalt, maltitol, sorbitol, or adonitol as a sugar alcohol plasticizer that is solid at room temperature demonstrated an acceptable level of transparency. The undesirable films had opacity values of <NUM>% or greater while the desirable films had opacity levels of <NUM>% or less. Example <NUM> shows that in films comprising <NUM> phr of the sugar alcohol plasticizer that is a solid at room temperature, films wherein the sugar alcohol plasticizer had a heat of fusion of about <NUM> J/g or less were acceptably transparent and films wherein the sugar alcohol plasticizer had a heat of fusion of about <NUM> J/g or greater at these loading rates had unacceptable cloudiness.

<NUM> mil thick water-soluble films were cast according to formulae <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, conditioned for <NUM> hours, and the transparency behavior of the water-soluble films was monitored. The transparency of the films was monitored for <NUM> days with exception of erythritol (formula <NUM>), <NUM> days, and mannitol (formula <NUM>), <NUM> days. The results are reproduced in the table below.

Films according to formulae <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> having the described amounts of dulcitol, pentaerythritol, maltitol, mannitol, erythritol, or adonitol as the sugar alcohol plasticizer that is a solid demonstrated an undesirable cloudy appearance. In contrast, films according to formulae <NUM>, <NUM>, and <NUM> comprising xylitol, isomalt or sorbitol as the sugar alcohol plasticizer that is a solid at room temperature demonstrated an acceptable level of transparency. The undesirable films had opacity values of <NUM>% or greater while the desirable films had opacity levels of <NUM>% or less. Example <NUM> shows that in films comprising <NUM> phr of the sugar alcohol plasticizer that is a solid at room temperature, films wherein the sugar alcohol plasticizer had a heat of fusion of about <NUM> J/g or less were acceptably transparent, with the exceptions of the films comprising sugar alcohol plasticizers that are a solid at room temperature with heats of fusion below <NUM> J/g but do not have two adjacent, sterically unhindered, hydroxyl groups in the same plane, maltitol and adonitol, the films being unacceptably cloudy. In contrast, films wherein the sugar alcohol plasticizer had a heat of fusion of about <NUM> J/g or greater at these loading rates were unacceptably cloudy in appearance.

Films according to formulae <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> having the described amounts of dulcitol, pentaerythritol, maltitol, xylitol, erythritol, adonitol or mannitol as the sugar alcohol plasticizer that is a solid demonstrated an undesirable cloudy appearance. In contrast, films according to formulae <NUM> and <NUM> comprising isomalt or sorbitol as the sugar alcohol plasticizer that is a solid at room temperature demonstrated an acceptable level of transparency. The undesirable films had opacity values of <NUM>% or greater while the desirable films had opacity levels of <NUM>% or less. Example <NUM> shows that in films comprising <NUM> phr of the sugar alcohol plasticizer that is a solid at room temperature, films wherein the sugar alcohol plasticizer had a heat of fusion of about <NUM> J/g or less were acceptably transparent, with the exception of the film comprising a sugar alcohol plasticizer that are a solid at room temperature with a heat of fusion below <NUM> J/g but does not have two adjacent, sterically unhindered, hydroxyl groups in the same plane, maltitol, the film being unacceptably cloudy. In contrast, films wherein the sugar alcohol plasticizer had a heat of fusion of about <NUM> J/g or greater at these loading rates were unacceptably cloudy in appearance.

<NUM> mil thick water-soluble films were cast according to formula <NUM>, conditioned for <NUM> hours, and were tested for tear strength, solubility, tensile strength, elongation at break, and energy to break, as described above. The results are reproduced in the table below.

Example <NUM> shows that when additional processing aids for antiblocking were added that good tear, tensile and solubility properties and acceptable transparency as visually observed were achieved.

<NUM> mil thick water-soluble films were cast according to formula <NUM>, conditioned for <NUM> hours, and were tested for film peak load followed by seal peak load at different temperatures. The peak load ratio was determined. The results are reproduced in the table below.

Claim 1:
A water-soluble film, comprising a water-soluble mixture of:
• a water-soluble resin comprising polyvinyl alcohol and having a weight average molecular weight of <NUM>,<NUM> to <NUM>,<NUM>;
• a compatibilizing agent that is carboxymethyl cellulose;
• a sugar alcohol plasticizer that is a solid at room temperature, wherein the sugar alcohol plasticizer comprises xylitol and a second sugar alcohol plasticizer that is a solid at room temperature;
wherein the water-soluble resin is present in an amount in a range of 35wt% to 90wt% based on the total weight of the film,
wherein the ratio of compatibilizing agent to sugar alcohol present in the water-soluble film is from <NUM>:<NUM> to <NUM>:<NUM>, or wherein the ratio of compatibilizing agent to xylitol is about <NUM>:<NUM>;
wherein the water-soluble film is transparent, such that when cast to a thickness of <NUM> and after storing for <NUM> days it has a measured opacity of <NUM>% or less, as determined by an X-RITE SP60 Series Sphere Spectrophotometer X-<NUM> colorimeter;
and wherein when the water-soluble film is <NUM> (<NUM> mils) thick it completely dissolves in less than <NUM> seconds in water at <NUM>.