Mixed starch / PVOH water-soluble membranes including salts

Abstract

The present invention relates to a water-soluble film comprising a mixture of a polyvinyl alcohol resin, a starch, and a salt wherein the salt is present in the water-soluble film in an amount sufficient to improve the compatibility of the polyvinyl alcohol resin with the starch.

Description

[0001] Cross-references to related applications

[0002] Claim is made in accordance with 35 USC § 119(e) for U.S. Provisional Patent Application No. 63 / 596,861, filed November 7, 2023, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to water-soluble films and related articles. More specifically, this disclosure relates to water-soluble films, including water-soluble films comprising a blend of polyvinyl alcohol resin and starch, said water-soluble film further containing one or more salts. Background Technology

[0004] Water-soluble polymer films are commonly used as packaging materials to simplify the dispersion, pouring, dissolving, and dispensing of materials to be delivered. For example, bags made from water-soluble films are commonly used to package household care compositions such as laundry and dishwashing detergents for personal care needs. Consumers can add the bagged composition directly to mixing containers such as buckets, sinks, or washing machines, for example, for laundry or tableware. Advantageously, this provides precise dispensing while eliminating the need for consumers to measure the composition. Using articles containing multiple compositions, such as those containing laundry or dishwashing detergents or other cleaning solvents in different compartments and one or more additional compositions (e.g., fabric softeners, brighteners, or fragrance additives), eliminates the need to add multiple products separately. Bagged compositions also reduce the hassle associated with dispensing similar compositions from containers, such as pouring compositions from bottles. In summary, soluble, pre-measured polymer film bags offer convenience for consumers in a variety of applications.

[0005] Bags containing water-soluble films can be produced, for example, by thermoforming. Thermoforming a film is a process of heating the film, shaping it (e.g., in a mold), and cooling it, so that the film retains its shape, such as that of the mold. Lowering the temperature at which the water-soluble film can be thermoformed can improve production costs and yield, for example, by reducing energy requirements and shortening heating and cooling times. However, such improvements should not come at the expense of film properties associated with the manufacture or use of the bag, such as acceptable mechanical strength, flexibility, and solubility.

[0006] Many consumers are increasingly inclined to use environmentally friendly or renewable products. Many conventional water-soluble membranes are made from materials that are not typically environmentally friendly or non-renewable, and often have a low renewable carbon index (RCI). Furthermore, many renewable components form rigid or brittle films and have low miscibility or compatibility with other polymer components in conventional water-soluble membranes. Therefore, the use of renewable components in such membranes is limited because water-soluble membranes need to exhibit mechanical properties suitable for processing and use in packaging (e.g., deformation recovery, high elongation, and strength properties).

[0007] Modifying the properties of polymer membranes by adding one or more metal salts has been reported. Specifically, several authors have noted that adding metal salts to polymer membranes can have a plasticizing effect, as typically demonstrated by lowering the glass transition temperature (Tg) of the membrane while simultaneously increasing the metal salt content. For example, Jiang et al. (Carbohydrate Polymers, 90 (2012) 1677–1684; International Journal of Biological Macromolecules, 82 (2016) 223–230) described the plasticization of starch / polyvinyl alcohol membranes by adding various metal chloride salts. Some of the added salts have adverse effects on water absorption or thermal stability.

[0008] Bhajantri et al. (Polymer, 47 (2006) 3591–3598) described the effects of barium chloride doping on the optical, thermal, and structural properties of polyvinyl alcohol films. The authors concluded that the dopant acts as a plasticizer, but high dopant concentrations cause phase separation into a polymer-enriched phase and a dopant-enriched phase.

[0009] Zidan (J. Appl. Polym. Sci., 88 (2003) 1115–1120) described the thermal properties of PVOH films filled with chromium fluoride and manganese chloride. Generally, increasing the filler content decreases the film's Tg and degradation temperature, and the authors concluded that the filler plays a role in plasticizing the film. Summary of the Invention

[0010] One aspect of this disclosure provides a water-soluble membrane comprising a mixture of polyvinyl alcohol resin, starch, and salt, wherein the amount of salt present in the water-soluble membrane is sufficient to improve the compatibility ratio of the polyvinyl alcohol resin to the starch relative to the compatibility ratio of the polyvinyl alcohol resin to the starch in the absence of the salt, as determined by a compatibility testing method.

[0011] Another aspect of this disclosure provides a water-soluble article comprising a water-soluble film according to this disclosure.

[0012] Another aspect of this disclosure provides an aqueous mixture comprising polyvinyl alcohol resin, starch, salt, and water, wherein the amount of salt present is sufficient to improve the compatibility ratio of the polyvinyl alcohol resin to the starch relative to the compatibility ratio of the polyvinyl alcohol resin to the starch in an otherwise identical aqueous mixture without the salt.

[0013] Another aspect of this disclosure provides a method for making polyvinyl alcohol and starch compatible in an aqueous mixture, the method comprising adding salt to the aqueous mixture, wherein the amount of salt added is sufficient to improve the compatibility ratio of the polyvinyl alcohol resin to the starch in the aqueous mixture relative to the compatibility ratio of the polyvinyl alcohol to the starch in an otherwise identical aqueous mixture without the salt.

[0014] For the compositions and methods described herein, optional features are selected from the various aspects, examples and instances provided herein, including but not limited to components, their compositional ranges, substituents, conditions and steps.

[0015] Further aspects and advantages will become apparent to those skilled in the art upon review of the following detailed description in conjunction with the accompanying drawings. While films, articles, bags, and methods of manufacturing and using thereof may have various forms of embodiments, the following description includes specific embodiments, wherein it should be understood that this disclosure is illustrative and not intended to limit the invention to the specific embodiments described herein. Detailed Implementation

[0016] This disclosure provides a water-soluble membrane comprising a mixture of polyvinyl alcohol resin, starch, and salt, wherein the amount of salt present in the water-soluble membrane is sufficient to improve the compatibility ratio of the polyvinyl alcohol resin to the starch relative to the compatibility ratio of the polyvinyl alcohol resin to the starch in the absence of the salt, as determined by a compatibility testing method.

[0017] This disclosure also provides an aqueous mixture comprising polyvinyl alcohol resin, starch, salt, and water, wherein the amount of salt present is sufficient to improve the compatibility ratio of the polyvinyl alcohol resin to the starch relative to the compatibility ratio of the polyvinyl alcohol resin to the starch in an otherwise identical aqueous mixture not containing the salt.

[0018] This disclosure also provides a method for making polyvinyl alcohol and starch compatible in an aqueous mixture, the method comprising adding salt to the aqueous mixture, wherein the amount of salt added is sufficient to improve the compatibility ratio of the polyvinyl alcohol resin to the starch in the aqueous mixture relative to the compatibility ratio of the polyvinyl alcohol to the starch in an otherwise identical aqueous mixture without the salt.

[0019] As used herein, “comprising” means the different components, ingredients, or steps that may be used in common in practicing this disclosure. Accordingly, the term “comprising” covers the more restrictive terms “generally consisting of” and “consisting of”. The compositions of the present invention may comprise, consist of, or be composed of any of the essential and optional elements disclosed herein. The invention, which is illustratively disclosed herein, may be practiced in the absence of any elements or steps not specifically disclosed herein.

[0020] The polymer industry (Encyclopedia of Polymer Science and Technology, John Wiley & Sons, Inc., 1967, Vol. 6, p. 764) defines a membrane (such as a membrane made according to this disclosure) as “a molded plastic with a relatively thin width and a maximum thickness of 0.010 inches.”

[0021] The membrane disclosed herein can be a self-supporting membrane and / or a uniform membrane. A self-supporting membrane is a membrane capable of supporting its own weight. A uniform membrane is a membrane with virtually no cracks, tears, pores, bubbles, or streaks.

[0022] According to MonoSol test method MSTM 205, a membrane with a thickness of about 1.5 mils (about 0.038 mm) considered water-soluble according to this disclosure dissolves in water at a temperature of 20°C (68℉) in 300 seconds or less. According to MonoSol test method MSTM 205, if a membrane with a thickness of about 1.5 mils (about 0.038 mm) according to this disclosure dissolves in water at a temperature of 20°C (68℉) in 250 seconds or less, 200 seconds or less, or 150 seconds or less, the membrane can be considered water-soluble.

[0023] Unless otherwise stated, all percentages, parts and ratios are based on the total dry weight of the formed film composition, and all measurements were performed at approximately 25°C. Unless otherwise stated, all such weights relating to the listed ingredients are based on activity levels and therefore do not include carriers or byproducts that may be present in commercially available materials.

[0024] All ranges described herein include all possible subsets of ranges and any combination of such subsets. By default, ranges include the stated endpoints unless otherwise stated. In the case of ranges of values ​​provided, it should be understood that each intermediate value between the upper and lower limits of the range, and any other stated or intermediate values ​​within the stated range, are covered within this disclosure. The upper and lower limits of these smaller ranges may be independently included within the smaller ranges and are also covered within this disclosure, subject to any expressly excluded limits within the stated ranges. Where a stated range includes one or both limits, it is also contemplated that ranges excluding any one or both of those included limits are part of this disclosure.

[0025] The dimensions and values ​​disclosed herein should not be construed as strictly limited to the exact numerical values ​​listed. Rather, unless otherwise stated, each such dimension is intended to include both the listed value and a functionally equivalent range around the stated value. For example, a dimension disclosed as “15 mm” is intended to include “about 15 mm”. The term “about” is used according to its common meaning, for example, to mean approximately or about. The term “about” may mean a set value or a range of values ​​±10%. The term “about” may mean a set value or a range of values ​​±5%. The term “about” may mean a set value or a range of values ​​±2%.

[0026] As used herein, and unless otherwise specified, the terms “wt.%” and “wt%” are intended to refer to the composition of the identified element in “dry” (non-aqueous) parts by weight of the whole film (where applicable) or in parts by weight of the whole composition encapsulated in a bag (where applicable).

[0027] As used herein, and unless otherwise specified, the term "PHR" ("phr") refers to the composition of the elements identified in every 100 parts of water-soluble polymer resin (whether polyvinyl alcohol or other polymer resin, unless otherwise specified) in a water-soluble membrane or solution used to prepare a water-soluble membrane. Unless otherwise specified, for membranes or solutions containing polyvinyl alcohol and starch, "water-soluble polymer resin" includes both polyvinyl alcohol and starch.

[0028] The membrane can be made by solution casting. The membrane can be used to form articles or bags through any suitable process, including thermoforming and, for example, solvent sealing or heat sealing of the membrane layer around the periphery of the article. For example, the bag can be used to dispense material to be delivered into a large volume of water.

[0029] As used herein, the “Renewable Carbon Index” (“RCI”) refers to the fraction or percentage of carbon atoms in the average structure of a material (e.g., a solvent, surfactant, or polymer, or a membrane or other article) derived from sources other than petroleum or natural gas feedstocks. Typically and desirablely, when water-soluble membranes are composed of natural materials or are produced sustainably, the RCI will generally exceed 0.75 or 75%, due to the use of materials found in nature and / or feedstocks derived from sustainable sources such as plants, fungi, or algae; products of bacterial fermentation processes; or processing products of plant, fungi, or algae-derived biomass. Challenges in formulating water-soluble membranes with the desired high RCI include a limited selection of economically viable low-RCI materials that deliver performance comparable to or better than conventional (i.e., non-naturally occurring or unsustainable) materials.

[0030] Unless otherwise stated, it is envisioned that the membrane, article, and related manufacturing and use methods include embodiments comprising any combination of one or more of the elements, features, and steps further described below (including the elements, features, and steps shown in the examples).

[0031] Water-soluble membrane

[0032] The membranes, related articles, and bags described herein may comprise water-soluble membranes containing salts distributed throughout the membrane or article. The water-soluble membranes may be solution-cast. Optionally, the membranes may further comprise one or more additives selected from: plasticizers, fillers, surfactants, anti-blocking agents, antioxidants, defoamers, bleaching agents, irritants, other functional ingredients, and combinations thereof.

[0033] The surface of the membrane, and related articles and bags containing the membrane, may be substantially salt-free. As used herein, the surface of the membrane is substantially salt-free if it contains less than 5 wt% salt based on the total weight of the membrane. Alternatively or additionally, the surface of the membrane is substantially salt-free if the concentration of salt in the outer layer of the membrane (defined as a layer extending from the outer surface of the membrane and penetrating to a depth not exceeding 10% of the membrane thickness) does not exceed 50 wt.% of the outer layer. Therefore, the surface of the membrane, and related articles and bags containing the membrane, may be substantially free of cations and / or anions containing salts.

[0034] The membrane can have any suitable thickness, and membrane thicknesses of about 76 micrometers (μm) or 88 micrometers are typical and particularly considered. Other values ​​and ranges considered include those in the range of about 5 μm to about 200 μm, or in the range of about 20 μm to about 100 μm, or about 60 μm to about 120 μm, or about 70 μm to about 100 μm, or about 40 μm to about 90 μm, or about 50 μm to about 80 μm, or about 60 μm to about 65 μm, or about 20 μm to about 60 μm, or about 20 μm to about 50 μm, or about 30 μm to about 40 μm, such as about 35 μm, about 36 μm, about 50 μm, about 65 μm, about 76 μm, about 88 μm, or about 90 μm.

[0035] Water-soluble membranes may have any renewable carbon index (RCI), for example, at least about 30%, about 40%, about 50%, about 55%, about 60%, about 65%, about 70%, or about 80%, or in a range formed by any such value as endpoints, for example, in the range of about 50% to about 90% or about 50% to about 80%.

[0036] According to the accelerated quantitative residue assessment test method described below, the water-soluble membrane can dissolve in water at a temperature of about 15°C, leaving residues of less than about 10 wt.%, less than about 5.0 wt.%, less than about 4.0 wt.%, less than about 3.0 wt.%, less than about 2.5 wt.%, or less than about 2.0 wt.% by weight of the water-soluble membrane. Residues at a temperature of about 15°C can be measured, for example, less than 5.0 wt.% by weight of the water-soluble membrane.

[0037] PVOH resin

[0038] The membrane described herein may include one or more polyvinyl alcohol (PVOH) polymers to constitute the PVOH resin content of the membrane, and may include PVOH copolymer resins.

[0039] Polyvinyl alcohol (PVOH) is a synthetic resin typically prepared by the alcoholysis (often referred to as hydrolysis or saponification) of polyvinyl acetate. With almost all acetate groups converted to alcohol groups, fully hydrolyzed PVOH is a strongly hydrogen-bonded, highly crystalline polymer that dissolves only in hot water at temperatures above about 140℉ (about 60°C). If a sufficient number of acetate groups are allowed to remain after the hydrolysis of polyvinyl acetate, i.e., the PVOH polymer is partially hydrolyzed, the polymer has weaker hydrogen bonding, lower crystallinity, and is generally soluble in cold water at temperatures below about 50℉ (about 10°C). Therefore, the partially hydrolyzed polymer is a vinyl alcohol-vinyl acetate copolymer, which is a PVOH copolymer, but is commonly referred to as a PVOH homopolymer.

[0040] PVOH resins may comprise fully or partially hydrolyzed homopolymers, said homopolymers comprising vinyl alcohol monomer units and optionally vinyl acetate monomer units. PVOH resins may comprise partially or fully hydrolyzed PVOH copolymers, said copolymers comprising anionic monomer units (i.e., anionically modified copolymers), vinyl alcohol monomer units, and optionally vinyl acetate monomer units. Anionic monomer units may be one or more of the following: vinylacetic 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 itaconic acid, dimethyl itaconic acid, itaconic anhydride, citraconic acid, monoalkyl citraconic acid, dialkyl citraconic acid, citraconic anhydride, mesocarboxylic acid, mesocarboxylic acid monoalkyl ester, mesocarboxylic acid dialkyl ester, glutaric acid, monoalkyl glutaric acid ester. Dialkyl glutarate, glutaric anhydride, vinyl sulfonic acid, alkyl sulfonic acid, vinyl sulfonic acid, 2-acrylamido-1-methylpropane sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, 2-methacrylamido-2-methylpropane sulfonic acid, ethyl 2-sulfoacrylate, alkali metal salts of the foregoing (e.g., sodium, potassium, or other alkali metal salts), esters of the foregoing (e.g., methyl, ethyl, or other C1-C4 or C6 alkyl esters), and combinations of the foregoing (e.g., multiple types of anionic monomers or equivalent forms of the same anionic monomer). For example, the anionic monomer may include one or more of monomethyl maleate and its alkali metal salt (e.g., sodium salt). The anionic monomer unit may be present in an average amount ranging from about 0.5 mol.% to about 10 mol.%, or from about 1 mol.% to about 8 mol.%, or from about 2 mol.% to about 5 mol.% in the anionicly modified PVOH copolymer.

[0041] Water-soluble membranes may contain a single PVOH resin or a blend of two or more PVOH resins. For example, the membrane may contain PVOH homopolymers, PVOH copolymers, blends of PVOH homopolymers and PVOH copolymers, blends of two or more PVOH homopolymers, blends of two or more PVOH copolymers, or combinations thereof. The two or more PVOH homopolymers may vary in viscosity, degree of hydrolysis, or a combination thereof. The two or more PVOH copolymers may be anionicly modified PVOH copolymers and may vary in viscosity, degree of hydrolysis, type of anionic monomer units, amount of anionic modification, or a combination thereof. The membrane may contain a PVOH homopolymer or a blend of PVOH homopolymers as the sole PVOH resin. For example, the total amount of PVOH resin in the membrane may range from about 10% to about 95% by weight, or about 30% to about 90%, or about 50% to about 90%, or about 60% to about 90%, or about 65% to about 85% based on the total weight of the membrane.

[0042] The degree of hydrolysis (DH or DH) of the total PVOH resin content of the membrane can be at least about 68%, 75%, 80%, 84%, or 85% and at most about 99.7%, 98%, or 96%, for example, in the range of about 75% to about 96%, or about 84% to about 90%, or about 85% to about 88%, or about 86.5%, or in the range of about 88% to 95%, about 89% to 93%, or about 89.5% to 92%, for example, about 89%, about 90%, about 92%, about 93%, about 94%, about 95%, or about 96%. As used herein, the degree of hydrolysis is expressed as the molar percentage of vinyl acetate units converted into vinyl alcohol units.

[0043] The degree of hydrolysis of resin blends can also be calculated by the arithmetic weighted average degree of hydrolysis (... Characterized by ), for example, PVOH resins containing two or more PVOH polymers. Through formula To calculate, where W i It is the weight percentage of the corresponding PVOH polymer, and H i It is the corresponding degree of hydrolysis.

[0044] The viscosity (µ) of the PVOH resin was determined by measuring freshly prepared solutions using a Brookfield LV viscometer with a UL adapter, as described in Annex E of British Standard EN ISO 15023-2:2006, Brookfield Test Method. International convention specifies the viscosity of a 4% (w / v) aqueous solution of polyvinyl alcohol at 20°C. Unless otherwise stated, all viscosities specified herein in centipoises (cP) should be understood as referring to the viscosity of a 4% (w / v) aqueous solution of polyvinyl alcohol at 20°C. Similarly, when a resin is described as having (or not having) a specific viscosity, unless otherwise stated, it means that the specified viscosity is the average viscosity of the resin, which inherently has the corresponding molecular weight distribution.

[0045] Suitable PVOH resins, used alone or in combination, can have viscosities ranging from about 3 cP to about 40 cP, or about 5 cP to about 38 cP, or about 10 cP to about 36 cP, or about 10 cP to about 20 cP, or about 12 cP to about 20 cP, or about 14 cP to about 19 cP, or about 3 cP to about 30 cP, or about 5 cP to about 25 cP, or about 5 cP to about 15 cP, or about 5 cP to about 10 cP, or about 5 cP to about 7 cP, or about 12 cP to about 34 cP, or about 14 cP to about 32 cP, or about 18 cP to about 30 cP, about 20 cP to about 28 cP, about 21 cP to about 26 cP, for example 32 cP, or 26 cP, or 23.5 cP, or 21 cP, or 19 cP, or 16.5 cP, or 14 cP or 6 cP. cP. It is well known in the art that the viscosity of PVOH resin is related to its weight-average molecular weight. Related, and viscosity is often used as Alternatives. When referring to the viscosity of PVOH resins containing PVOH polymer blends, the weighted natural logarithm average viscosity is used. PVOH resins containing two or more PVOH polymers Through formula To calculate, where μ i This is the viscosity of the corresponding PVOH polymer.

[0046] Bio-based PVOH

[0047] Generally, "bio-based" materials refer to materials containing carbon derived from biomass. Biomass refers to resources derived from living organisms that are not depleted, including renewable organic resources derived from organisms but excluding resources derived from fossils and petroleum. Bio-based materials typically have a higher RCI (Regenerative Cubic Index) than otherwise identical non-bio-based materials.

[0048] The PVOH resin in the membrane disclosed herein may include bio-based PVOH. Bio-based PVOH includes PVOH containing at least a portion of the carbon in the PVOH derived from biomass. Specifically, bio-based PVOH includes PVOH produced by hydrolyzing or saponifying a blend of bio-based polyvinyl acetate or polyvinyl acetate comprising bio-based polyvinyl acetate. Furthermore, bio-based polyvinyl acetate includes polyvinyl acetate produced by polymerizing a blend of bio-based vinyl acetate or vinyl acetate comprising bio-based vinyl acetate. Typically, bio-based vinyl acetate includes vinyl acetate containing at least a portion of the carbon in the vinyl acetate derived from biomass. For example, vinyl acetate can be obtained by a gas-phase reaction of ethylene, acetic acid, and oxygen; bio-based vinyl acetate can refer to vinyl acetate containing at least a portion of ethylene and / or acetic acid derived from biomass. For example, bio-based vinyl acetate includes vinyl acetate obtained by reacting ethylene, acetic acid, and oxygen, wherein at least a portion of the ethylene and / or at least a portion of the acetic acid is bio-based. Therefore, bio-based PVOH includes PVOH in which a portion of the carbon contained in PVOH comes from bio-based ethylene and / or bio-based acetic acid.

[0049] Plants that can serve as sources of bio-based ethylene and / or bio-based acetic acid include, but are not limited to, potatoes, sweet potatoes, sugar beets, rice, wheat, palm oil, algae, corn, sugarcane, sorghum, and cassava. Similarly, bio-based acetic acid can also be produced via the bioethanol route.

[0050] Bio-based PVOH is characterized by carbon-14 ( 14 C) Content. Generally, the abundance of biomass-derived resources is relatively high compared to that of petroleum-derived resources. 14 The abundance of C (i.e., 14 The percentage of carbon in the total carbon content is higher. Specifically, the abundance of bio-based ethylene and acetic acid is higher than that of petroleum-derived ethylene and acetic acid. 14 The abundance of C is generally higher, and consequently, the abundance of bio-based PVOH is higher than that of completely petroleum-derived PVOH. 14 C abundance is usually higher. Therefore, in polymers (such as PVOH resins) 14 The abundance of carbon (C) can serve as an indicator of the bio-based content of polymers. (Materials) 14 The C content can be measured in known ways, such as by mass spectrometry.

[0051] The membranes disclosed herein may include bio-based PVOH, as described in U.S. Patent Application Publication No. 2023 / 0257491A1, U.S. Patent Application Publication No. 2023 / 0070770A1, and International Patent Application Publication WO 2022 / 034906A1, all of which are hereby incorporated by reference in their entirety. The PVOH resin comprising the membranes of this disclosure may comprise petroleum-derived PVOH, or bio-based PVOH, or a blend of petroleum-derived PVOH and bio-based PVOH. For membranes comprising blends of petroleum-derived PVOH and bio-based PVOH, the ratio of petroleum-derived PVOH to bio-based PVOH is not particularly limited and may range, for example, from about 99:1 to about 1:99, or about 95:5 to about 5:99, or about 80:20 to about 20:80, or about 70:30 to about 30:70, or about 60:40 to about 40:60.

[0052] Besides PVOH resin, other water-soluble polymers used in the membrane may include, but are not limited to, polyacrylates, water-soluble acrylate copolymers, polyvinylpyrrolidone, polyethyleneimine, pullulan, water-soluble natural polymers (including but not limited to guar gum, gum arabic, agar, xanthan gum, carrageenan, pectin, amylopectin, alginic acid and its salts), starch, water-soluble polymer derivatives (including but not limited to modified starch, ethoxylated starch, hydroxyethylated starch and hydroxypropylated starch), copolymers of the foregoing substances, and combinations of any of the foregoing substances. Other water-soluble polymers may include polyepoxides, polyacrylamides, polyacrylic acid and its salts, cellulose, cellulose ethers, cellulose esters, cellulose amides, polyvinyl acetate, polycarboxylic acids and their salts, polyamino acids, polyamides, gelatin, methylcellulose, carboxymethylcellulose and its salts, dextrin, ethylcellulose, hydroxyethylcellulose, hydroxypropyl methylcellulose, maltodextrin, polymethyl methacrylate, and combinations of any of the foregoing substances. The membrane may include polyethyleneimine, polyvinylpyrrolidone, polyepoxide, polyacrylamide, cellulose ether, cellulose ester, cellulose amide, polyvinyl acetate, polyamide, gelatin, methylcellulose, carboxymethylcellulose, carboxymethylcellulose salt, dextrin, ethylcellulose, hydroxyethylcellulose, hydroxypropyl methylcellulose, maltodextrin, starch, modified starch, guar gum, gum arabic, agar, xanthan gum, carrageenan, polyacrylate, polyacrylate, and copolymers of any of the foregoing substances. Such water-soluble polymers, whether PVOH or others, are commercially available from various sources.

[0053] starch

[0054] The water-soluble membrane disclosed herein includes starch, such as water-soluble starch. The starch may comprise one or more starches selected from: unmodified starch, starch modified with nonionic groups, starch modified with anionic groups, and starch modified with cationic groups. The starch may comprise starch modified with nonionic groups. The starch may comprise starch modified with cationic groups.

[0055] Unmodified starch can contain naturally derived polysaccharides composed of dehydrated glucose units with α-1,4 and α-1,6 glycosidic bonds, forming either linear or branched chains. Linear starch is called amylose, and branched starch is called amylopectin. Generally, starches with lower molecular weights and lower amylose content are more easily gelatinized and dissolved in water. Unmodified starch can include starch for which no chemical moiety has been added to the polysaccharide. For example, unmodified starch can include starch whose molecular weight has been reduced through techniques such as acid hydrolysis.

[0056] For example, the starch aging percentage can be at least about 5 wt.%, at least 6 wt.%, at least about 7 wt.%, at least about 8 wt.%, at least about 9 wt.%, at least about 10 wt.%, at least about 11 wt.%, at least about 12 wt.%, at least about 13 wt.%, at least about 14 wt.%, at least about 15 wt.%, at least about 16 wt.%, at least about 17 wt.%, at least about 18 wt.%, at least about 19 wt.%, at least about 20 wt.%, at least about 21 wt.%, at least about 22 wt.%, at least about 23 wt.%, at least about 24 wt.%, at least about 25 wt.%, at least about 26 wt.%, at least about 27 wt.%, at least about 28 wt.%, at least about 29 wt.%, or at least about 30 wt.%, or within the relevant range, for example, at least 10 wt.% and at most 40 wt.%, or at least 10 wt.% and at most 30 wt.%. wt.%. The cooked % of the starch can be at least about 15 wt.%. As used herein, cooked % is the maximum weight percentage of starch dissolved in water after being heated and mixed in water at 95°C for 30 minutes.

[0057] Modified starch can include physically modified starches, such as discrete amylose or amylopectin, or hydrothermally treated starches; enzyme-modified starches, such as hydrolyzed dextrin, enzymatically decomposed dextrin, or amylose; chemically decomposed starches; or combinations thereof. Chemically modified starches can include chemically decomposed starches, such as acid-treated starches, hypochlorous acid-oxidized starches, or formaldehyde starches; starches modified with nonionic groups, including esterified starches and etherified starches; and / or starches modified with ionic groups, including anionicly modified starches and cationicly modified starches. Esterified starches can include acetate-esterified starches, succinate-esterified starches, nitrate-esterified starches, phosphoric acid-esterified starches, urea-phosphate-esterified starches, xanthate-esterified starches, acetoacetic acid-esterified starches, etc. Etherified starches can include allyl etherified starches, methyl etherified starches, carboxymethyl etherified starches, hydroxyethyl etherified starches, hydroxypropyl etherified starches, etc. Non-limiting examples of starches modified with nonionic groups include starches modified with hydroxyethyl and hydroxypropyl groups, as well as starches modified with octenyl succinic anhydride.

[0058] The degree of modification of the modified starch can range from about 0.01 mol.% to about 10 mol.%, about 0.05 mol.% to about 5 mol.%, about 0.05 mol.% to about 4 mol.%, about 0.05 mol.% to about 3 mol.%, about 0.05 mol.% to about 2 mol.%, about 0.05 mol.% to about 1 mol.%, about 0.1 mol.% to about 1 mol.%, about 0.1 mol.% to about 0.5 mol.%, about 0.1 mol.% to about 0.3 mol.%, about 0.05 mol.% to about 3.5 mol.%, about 1.0 mol.% to about 5.0 mol.%, or about 1 mol.% to about 3.5 mol.%, for example, about 0.18 mol.% or 0.21 mol.%.

[0059] The molecular weight of starch, the amylose / amylose ratio, the type of modification, and the level of modification can significantly affect its cooking percentage, the rheological properties of the resulting starch solution, and the interaction and compatibility of starch with other materials (such as polyvinyl alcohol). The cooking percentage of unmodified starch extracted directly from plants is typically only about 1-2%. Acid hydrolysis can reduce the molecular weight of starch, which can increase the maximum cooking percentage. Certain types of chemical modification of starch can increase the cooking percentage, inhibit sedimentation, and reduce the viscosity of starch solutions. The second and / or third carbon of the glucose unit can be modified by reaction with, for example, secondary alcohols. Chemical modification can provide, for example, nonionic (e.g., hydroxyethyl, hydroxypropyl, octenyl), anionic (e.g., carboxyl), or cationic (e.g., trimethylammonium) modification of starch.

[0060] Starch can consist of essentially gelatinized starch.

[0061] The average molecular weight of starch can range from about 10. 3 -10 6 g / mol or approximately 10 4 -10 5 g / mol.

[0062] The amylose content of starch can range from about 0 to about 50 wt.%, about 0 to about 40 wt.%, about 0 to about 30 wt.%, or about 0 to about 25 wt.%.

[0063] The Brookfield viscosity of a 5 wt.% aqueous solution of starch at a shear rate of about 20 rpm and a temperature of about 87.8°C (about 190℉) can range from about 1-2000 cP, about 1-1500 cP, about 1-1000 cP, about 1-900 cP, about 1-800 cP, about 1-700 cP, about 1-600 cP, about 1-500 cP, about 2-400 cP, about 2-300 cP, about 2-200 cP, or about 2-100 cP.

[0064] Starch may be present in an amount ranging from about 5 wt.% to about 95 wt.%, or about 10 wt.% to about 90 wt.%, or about 20 wt.% to about 80 wt.%, or about 30 wt.% to about 70 wt.% based on the weight of the water-soluble film.

[0065] Water-soluble modified starch may include starch modified with cationic groups. Cationic modified starch may include starch modified with cationic amine or ammonium groups, including starch modified with primary amine groups, starch modified with secondary amine groups, starch modified with tertiary amine groups, or starch modified with quaternary amine or ammonium groups. Cationic modified starch may include starch modified with quaternary ammonium groups. Non-limiting examples of quaternary ammonium group modified starch include starch modified with trimethylammonium groups, starch modified with 2-diethylaminoethyl halide salts, and starch modified with 2,3-epoxypropyltrimethylammonium halide salts.

[0066] Cationic modified starch may include cationic quaternary ammonium modified starch, such as starch having the structure of formula A, wherein R 1 R 2 and R 3 Each independently constitutes H, C1-C 10 Alkyl or C1-C 10 hydroxyalkyl, wherein R 4 For C1-C 10 Alkylene, wherein X is the derivative of R 4The starch is connected to an ether or ester bond, or a hydrocarbon group containing oxygen, nitrogen or sulfur.

[0067]

[0068] Formula A

[0069] R 1 R 2 and R 3 It can be the same C1-C4 alkyl group, and R 4 It can be a C1-C6 hydroxyalkylene group. On the other hand, R 4 It can be a C3-C6 hydroxyalkylene group. On the other hand, R 1 R 2 and R 3 It can be methyl, and R 4 It can be a C3-C6 hydroxyalkylene group.

[0070] The cationic quaternary ammonium group can be 2-hydroxy-3-(trimethylammonium)propyl, 2-diethylaminoethyl, or 2,3-epoxypropyltrimethylammonium group or a combination thereof.

[0071] Cationic modified starch may include starch modified with trimethylammonium groups.

[0072] The cationic modified starch may contain starch modified with the following: 2-diethylaminoethyl salt, 2,3-epoxypropyltrimethylammonium salt or 2-hydroxy-3-(trimethylammonium)propyl salt or a combination thereof.

[0073] The 2-diethylaminoethyl salt may contain 2-diethylaminoethyl halide, the 2,3-epoxypropyltrimethylammonium salt may contain 2,3-epoxypropyltrimethylammonium halide, and the 2-hydroxy-3-(trimethylammonium)propyl salt may contain 2-hydroxy-3-(trimethylammonium)propyl halide.

[0074] The 2-diethylaminoethyl salt may contain 2-diethylaminoethyl chloride, the 2,3-epoxypropyltrimethylammonium salt may contain 2,3-epoxypropyltrimethylammonium chloride, and the 2-hydroxy-3-(trimethylammonium)propyl salt may contain 2-hydroxy-3-(trimethylammonium)propyl chloride.

[0075] The starch may further comprise unmodified starch and / or starch modified with nonionic groups at a modification level of about 1 wt.% to about 5 wt.%.

[0076] Salt

[0077] The water-soluble membrane disclosed herein includes salts. Salts may contain metal cations. Salts may contain monovalent metal cations. Salts may contain polyvalent metal cations. Salts may contain divalent metal cations. Salts may contain trivalent metal cations. Salts may contain cations selected from the group consisting of lithium, sodium, potassium, calcium, magnesium, manganese, barium, iron, and aluminum. Salts may be selected from calcium salts, magnesium salts, manganese salts, barium salts, iron salts, and mixtures thereof. Salts may be selected from calcium salts, magnesium salts, manganese salts, and mixtures thereof. Salts may contain calcium salts. Salts may contain magnesium salts. Salts may contain manganese salts.

[0078] Salts can contain nonmetallic cations. Salts can contain ammonium cations. Salts can contain substituted ammonium cations.

[0079] Salts may contain organic cations. Suitable organic cations include, but are not limited to, guanidine. Salts may also contain inorganic nonmetallic cations. Suitable inorganic nonmetallic cations include, but are not limited to, ammonium.

[0080] Salts can contain inorganic anions. Not intended to be theoretically constrained, it is believed that incorporating salts containing inorganic anions into water-soluble membranes can improve the membrane's water retention capacity and effectively plasticize the membrane. If present, the inorganic anions can be selected from halide ions, nitrate ions, sulfate ions, phosphate ions, and combinations thereof. Inorganic anions can be halide ions. Halide ions can be selected from chloride ions, fluoride ions, bromide ions, iodide ions, or combinations thereof. Inorganic anions can be selected from chloride ions and fluoride ions. Salts can contain calcium chloride.

[0081] Water-soluble membranes can contain polyvalent salts comprising inorganic anions and polyvalent salts comprising organic anions. Suitable organic anions include, but are not limited to, acetate, citrate, gluconate, lactate, and mixtures thereof. It is not intended to be theoretically constrained, but it is considered that salts containing organic anions are generally less effective at retaining water than salts containing inorganic anions, and therefore provide less plasticizing effect to the membrane; however, it is further considered that polyvalent salts containing organic anions can be an additional source of polyvalent cations, thereby helping to reduce the crystallinity imparted by polyvalent salts containing inorganic anions.

[0082] Generally, the amount of salt included in a film, solution, or mixture containing polyvinyl alcohol resin and starch can be within the range of, and includes, the amount required to achieve adequate compatibility between the polyvinyl alcohol resin and starch, as defined herein. The amount of salt included in a film, solution, or mixture containing polyvinyl alcohol resin and starch need not be sufficient to achieve adequate compatibility between the polyvinyl alcohol resin and starch. The amount of salt can be sufficient to improve the compatibility of the polyvinyl alcohol in the starch relative to the compatibility of the polyvinyl alcohol resin with the starch in the absence of said salt, as determined by a compatibility testing method.

[0083] The amount of salt in the membrane can be at least about 1 phr, or at least about 2 phr, about 3 phr, about 4 phr, about 5 phr, about 10 phr, about 15 phr, about 20 phr, about 25 phr, about 30 phr, or within a range formed by any such value as an endpoint.

[0084] Salt may be provided in an amount sufficient to reduce membrane disintegration time by at least about 5%, or at least about 10%, or at least about 20%, or at least about 30%, or at least about 40%, or at least about 50%. It is not intended to be theoretically construed as improving the membrane's water retention capacity and making it more readily disintegrate in water by incorporating salts containing inorganic anions into water-soluble membranes.

[0085] The amount of added salt sufficient to improve the compatibility of polyvinyl alcohol resin and starch in aqueous mixtures may also be sufficient to affect the mechanical properties of membranes containing both polyvinyl alcohol resin and starch. Specifically, the added salt can decrease the tensile strength of the membrane or increase its elasticity. It is not intended to be theoretically constrained, but it is thought that certain salts (e.g., those containing "liquid-free" ions typically characterized by the ability to disrupt the hydrogen-bonded structure of water, such as Ca) will contribute to the compatibility of membranes containing both polyvinyl alcohol resin and starch. 2+ or Mg 2+ Adding salts to PVOH / starch-containing membranes can increase the membrane's ability to absorb and retain water, and the additional water can effectively plasticize the membrane. These effects of salt addition can be offset, for example, by adjusting other components of the membrane, such as reducing the amount of plasticizer in the membrane.

[0086] Water-soluble membranes can contain polyvalent salts and monovalent metal salts. Monovalent metal salts can contain monovalent cations selected from the group consisting of lithium, sodium, potassium, and combinations thereof. The monovalent cation can be lithium. Monovalent metal salts can contain any inorganic or organic anion disclosed herein.

[0087] Secondary components

[0088] Water-soluble films containing resins disclosed herein may contain other additives and processing agents, such as, but not limited to: plasticizers, plasticizer compatibilizers, surfactants, lubricants, release agents, fillers, extenders, crosslinking agents, antiblocking agents, antioxidants, detackifiers, defoamers, nanoparticles such as layered silicate-type nanoclays (e.g., sodium montmorillonite), bleaching agents (e.g., sodium metabisulfite, sodium bisulfite, or others), aversive agents and irritants such as bittering agents (e.g., denatammonium salts, such as denatammonium benzoate, denatammonium sugar, and denatammonium chloride; sucrose octaacetate; quinine; flavonoids such as quercetin and naringenin; and quassinolides such as quassinolide and strychnine), capsaicin, piperine, allyl isothiocyanate, and resin toxins, and other functional components. Films including plasticizers are particularly considered. Water-soluble membranes may include surfactants, antioxidants, bittering agents, detergency polymers, anti-redeposition aids, chelating agents, detergent builders, fragrances, or combinations thereof. The amounts of the aids may be, for example, alone or together, up to about 50 wt.%, 20 wt.%, 15 wt.%, 10 wt.%, 5 wt.%, 4 wt.% and / or at least 0.01 wt.%, 0.1 wt.%, 1 wt.%, or 5 wt.%.

[0089] plasticizer

[0090] Plasticizers are liquids, solids, or semi-solids added to materials (typically resins or elastomers) to make them softer, more flexible (by lowering the glass transition temperature of the polymer), and easier to process. At low plasticizer levels, films may become brittle, difficult to process, or prone to breakage. At high plasticizer levels, films may be too soft, too weak, or difficult to process for the desired application. Water is considered a very effective plasticizer for PVOH and other polymers, including but not limited to water-soluble polymers; however, the volatility of water limits its practicality because polymer films need to have at least a certain resistance (toughness) to a variety of environmental conditions, including both low and high relative humidity. Therefore, as used herein, the term "plasticizer" does not encompass water.

[0091] Generally, for water-soluble membranes of this disclosure that include salts, the water-soluble membrane may further include a plasticizer. The plasticizer may include, but is not limited to, polyols, sugar alcohols, polyethers, amines, or mixtures thereof. For example, the plasticizer may comprise a plasticizer selected from the group consisting of: polyols, sugar alcohols, polyethers, amines, or combinations thereof. The plasticizer may include, but is not limited to, glycerol, diglycerol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, up to 400 MW of polyethylene glycol, neopentyl glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, polypropylene glycol, 2-methyl-1,3-propanediol, trimethylolpropane, polyether polyols, isomaltulose, maltitol, sorbitol, xylitol, erythritol, calendula alcohol, galactitol, pentaerythritol, mannitol, ethanolamine, and mixtures thereof. The plasticizer does not include divalent metals.

[0092] The total amount of non-aqueous plasticizer may be in the range of about 10 to about 50 parts by weight (PHR) per 100 parts of PVOH resin, or about 10 PHR to about 45 PHR, or about 15 PHR to about 45 PHR, or about 15 to 40 PHR, or about 20 PHR to about 40 PHR, or about 25 PHR to about 40 PHR, or about 25 PHR to about 35 PHR, or about 25 PHR PHR to about 30 PHR.

[0093] In some embodiments, the water-soluble membrane of this disclosure may be substantially free of the non-aqueous plasticizers described above (i.e., polyols, sugar alcohols, polyethers, or amine plasticizers). When the water-soluble membrane comprises components of less than about 5 PHR, less than about 4 PHR, less than about 3 PHR, less than about 2 PHR, or less than about 1 PHR, the membrane is substantially free of the components.

[0094] surfactants

[0095] Surfactants for water-soluble films are well known in the art. Optionally, surfactants are included to help disperse the resin solution during casting to form a film. Suitable surfactants can include nonionic, cationic, anionic, and zwitterionic classes. Suitable surfactants include, but are not limited to, propylene glycol, diethylene glycol, monoethanolamine, polyoxyethylene polyoxypropylene glycol, alcohol ethoxylates, alkylphenol ethoxylates, tertiary acetylenols and alkanolamides (nonionic), polyoxyethylene amines, quaternary ammonium salts and quaternized polyoxyethylene amines (cationic), alkali metal salts of higher fatty acids containing about 8 to 24 carbon atoms, alkyl sulfates, alkyl polyethoxylated sulfates and alkylbenzene sulfonates (anionic), and aminooxyions, N-alkyl betaine and sulfobetaine (zwitterionic). Other suitable surfactants include dialkyl sulfosuccinate, lactated fatty acid esters of glycerol and propylene glycol, lactate esters of fatty acids, sodium alkyl sulfate, polysorbate 20, polysorbate 60, polysorbate 65, polysorbate 80, alkyl polyethylene glycol, lecithin, acetylated fatty acid esters of glycerol and propylene glycol, sodium lauryl sulfate, acetylated esters of fatty acids, myristyl dimethylamine oxide, trimethyl tallow alkyl ammonium chloride, quaternary ammonium compounds, their salts, and combinations of any of the foregoing substances. Surfactants may comprise surfactants selected from the group consisting of: polyoxyethylene polyoxypropylene glycol, alcohol ethoxylates, alkylphenol ethoxylates, tert-acetylenols and alkanolamides, polyoxyethylene amines, quaternary ammonium salts and quaternized polyoxyethylene amines, as well as aminooxygen ions, N-alkyl betaine, sulfobetaine, and combinations thereof.

[0096] The amount of surfactant in water-soluble films can range from about 0.1 wt.% to about 8.0 wt.%, or about 1.0 wt.% to about 7.0 wt.%, or about 3 wt.% to about 7 wt.%, or about 5 wt.% to about 7 wt.%, or about 0.1 wt.% to 2.5 wt.%. Insufficient surfactant may sometimes result in pores in the cast film, while excessive surfactant may cause an oily or greasy feel due to the presence of excessive surfactant on the film surface.

[0097] In some embodiments, the water-soluble membranes of this disclosure may be substantially free of the surfactants described above.

[0098] Lubricant / Mold Release Agent

[0099] Lubricants / release agents suitable for the water-soluble films described herein may include, but are not limited to, fatty acids and their salts, fatty alcohols, fatty esters, fatty amines, fatty amine acetates, and fatty amides. Preferred lubricants / release agents are fatty acids, fatty acid salts, and fatty amine acetates. The amount of lubricant / release agent in the water-soluble film may range from about 0.02 wt.% to about 1.5 wt.%, optionally from about 0.1 wt.% to about 1 wt.%.

[0100] Defoamer

[0101] The water-soluble membranes disclosed herein may also include defoamers. Defoamers can help foam bubbles coalesce. Suitable defoamers for use in the water-soluble membranes according to this disclosure include, but are not limited to, hydrophobic silica, such as fine-grained silica, siloxanes, silicone ethers, or fumed silica, and proprietary non-mineral oil defoamers, including Foam Blast® defoamers available from Emerald Performance Materials, including 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. For example, defoamer can be used in amounts of 0.5 PHR or less, such as 0.05 PHR, 0.04 PHR, 0.03 PHR, 0.02 PHR or 0.01 PHR.

[0102] antioxidants

[0103] The water-soluble membranes disclosed herein may further include antioxidants, such as chloride ion scavengers. Suitable antioxidants / chloride ion scavengers include sulfites, bisulfites, thiosulfates, iodides, nitrites, carbamates, ascorbic acid salts, and combinations thereof. Antioxidants may comprise propyl gallate (PGA), citric acid (CA), sodium metabisulfite (SMBS), carbamates, ascorbic acid salts, or combinations thereof. The antioxidant may range from about 0.25 to about 1.5 PHR, for example, amounts of about 0.25 PHR, about 0.30 PHR, about 0.35 PHR, about 0.40 PHR, about 0.45 PHR, about 0.5 PHR, about 0.75 PHR, about 1.0 PHR, about 1.25 PHR, or about 1.5 PHR are included in the membrane.

[0104] filler

[0105] Fillers may be included in the water-soluble membrane and may include bulking agents, expanders, anti-blocking agents, detackifiers, and combinations thereof. Fillers suitable for the water-soluble membranes disclosed herein include, but are not limited to, starch, modified starch, cross-linked polyvinylpyrrolidone, cross-linked cellulose, microcrystalline cellulose, silica, metal oxide ions, calcium carbonate, talc, mica, stearic acid, and their metal salts, such as magnesium stearate. The amount of filler / expansioner / anti-blocking agent / detackifier in the water-soluble membrane may, for example, be in the range of about 1 wt.% to about 6 wt.%, or about 1 wt.% to about 4 wt.%, or about 2 wt.% to about 4 wt.%, or about 1 PHR to about 6 PHR, or about 1 PHR to about 4 PHR, or about 2 PHR to about 4 PHR.

[0106] Water-soluble membranes may include fillers of 2 or more PHR (e.g., 2 to 6 PHR or 2 to 4 PHR). For example, a membrane may include fillers of 2 or more PHR (e.g., 2 to 6 PHR or 2 to 4 PHR), and the fillers may contain bulking agents, anti-blocking agents, or combinations thereof. It is not intended to be theoretically constrained, but it is thought that when plasticizers are included in an amount greater than or equal to 30 PHR (e.g., in the range of 30 to 50 PHR), fillers comprising 2 or more PHR (e.g., 2 to 6 PHR or 2 to 4 PHR) may be used to prevent plasticizers from leaching out or migrating from the membrane.

[0107] The anti-blocking agent may be present in the film in amounts of at least 0.1 PHR, or at least 0.5 PHR, or at least 1 PHR, or ranging from about 0.1 PHR to 5.0 PHR, or from about 0.1 PHR to about 3.0 PHR, or from about 0.4 PHR to 1.0 PHR, or from about 0.5 PHR to about 0.9 PHR, or from about 0.5 PHR to about 2 PHR, or from about 0.5 PHR to about 1.5 PHR, or from 0.1 PHR to 1.2 PHR, or from 0.1 PHR to 2.7 PHR, such as 0.5 PHR, 0.6 PHR, 0.7 PHR, 0.8 PHR, or 0.9 PHR. Suitable anti-blocking agents may include, but are not limited to, SiO2, stearic acid, and certain starches. The use of starch as an anti-blocking agent or friction reducer is described in U.S. Patent Application Publication No. 2018 / 0118906A1, which is hereby incorporated by reference in its entirety. In embodiments where starch is present in the membrane as an anti-blocking agent or friction reducer, the amount of starch present in the membrane as an anti-blocking agent or friction reducer should be considered as the amount of starch added based on the compatibility ratio measured with the polyvinyl alcohol comprising the membrane.

[0108] Suitable median particle size for anti-blocking agents includes median sizes in the following ranges: about 3 or about 4 micrometers to about 11 micrometers, or about 4 micrometers to about 8 micrometers, or about 5 micrometers to about 6 micrometers, for example, 5, 6, 7, 8 or 9 micrometers.

[0109] Aversion agent

[0110] Aversive agents can be incorporated into water-soluble membranes or applied as a coating. Aversive compounds such as bittering agents or irritants can be added to prevent children or animals from ingesting the membrane. Bittering agents add bitterness to the composition to which they are added. Suitable bittering agents include denatum salts (e.g., denatum benzoate, denatum sugar, denatum chloride), sucrose octaacetate, quinine, flavonoids (e.g., quercetin, naringenin), and quassinolide (e.g., bittering agent, strychnine). Irritants add a pungent taste when ingested and a burning sensation when applied topically to the skin. Suitable irritants include capsaicin, piperine, allyl isothiocyanate, and resin toxins. Suitable incorporation levels vary depending on the specific bittering or irritant material. As understood by those skilled in the art, the aversive component should be incorporated at a level sufficiently high to impart an unpleasant taste or sensation, but low enough to avoid potential toxicity of the aversive agent itself. The anaerobic agent can be diluted commercially or otherwise mixed with a solvent to facilitate mixing with other water-soluble film components or application as a coating to water-soluble films. Such solvents can be selected from water, low molecular weight alcohols (methanol, ethanol, etc.) or plasticizers disclosed herein.

[0111] Methods for manufacturing membranes

[0112] Water-soluble films, including those made with the water-soluble resins disclosed herein, can be manufactured by any suitable method. Processes for manufacturing water-soluble films and bags include solvent casting, blow molding, extrusion, and blow extrusion, as known in the art. Solvent casting processes for manufacturing polyvinyl alcohol-containing films are well known in the art. For example, in a film-forming process, polyvinyl alcohol resin, optionally other film-forming resins, and secondary additives can be dissolved in a solvent (typically water), metered onto a surface, substantially dried (or forced dried) to form a cast film, and then the resulting cast film is removed from the cast surface. These processes can be performed in batches and are more efficient when carried out as a continuous process.

[0113] In forming a continuous film containing polyvinyl alcohol, conventional practice involves metering a solution or mixture containing polyvinyl alcohol onto a moving casting surface, such as a continuously moving metal cylinder or belt, thereby substantially removing the solvent from the liquid, thus forming a self-supporting cast film, and then peeling the resulting cast film off the casting surface. The solution or mixture may optionally be metered or coated onto a carrier film, release liner, or removable backing, whereby, after solvent removal, the resulting cast film or coating may separate from the carrier film, release liner, or removable backing (e.g., immediately after drying or at a later point in time (e.g., before use)) or remain attached to the carrier film, release liner, or removable backing.

[0114] Films according to the disclosure herein can be produced by solvent casting, for example using a solvent belt casting system. The system may include tanks with optional secondary additives for mixing and / or storing polymer solutions or mixtures, said tanks for use with a belt casting machine having at least first and second rotating drums around which a continuous belt (e.g., a metal belt) is tensioned to travel as the drums rotate. A sheet die can apply the polymer solution or mixture from the tank onto the metal belt, wherein a drying chamber located downstream of the sheet die, surrounding at least a portion of the metal belt, is used to remove solvent as the polymer solution or mixture travels in a sheet on the metal belt. Additionally, a release coating can be used to provide one or more advantages for the film and / or process. For example, a release coating can significantly reduce or eliminate air bubbles in the resulting polymer film, or a release coating can improve the ease of releasing the resulting film from the cast surface. A roll coater release coating applicator, in communication with a batch of release coating and a portion of the belt, can transfer a fluid release coating to the cast surface before applying the polymer solution or mixture onto the belt. Suitable solvent-based tape casting systems and related materials are further described in U.S. Patent Application Publications No. 2006 / 0081176 A1 and No. 2007 / 0085234A1, the disclosures of which are incorporated herein by reference in their entirety.

[0115] Generally, the casting surface can be any suitable substrate known to those skilled in the art for producing polymer films. The substrate can be a casting roller or cylinder, a casting tape, or a combination thereof. As used herein, the substrate is used to produce a polymer film from a polymer resin or a polymer resin solution or mixture. The substrate includes a substrate surface, and the substrate surface is coated with a release coating. The polymer resin solution or mixture can be cast onto the substrate while the substrate is being moved (e.g., rotated). The substrate can be a casting cylinder. The substrate can be a casting tape. The substrate can comprise stainless steel and optionally may have a stainless steel surface. The substrate can comprise stainless steel, which may optionally be plated, for example, chromium plated, nickel plated, zinc plated, or a combination thereof.

[0116] Optionally, the water-soluble membrane can be a self-supporting membrane consisting of one or more similar layers.

[0117] PVOH / starch film

[0118] The water-soluble film containing polyvinyl alcohol resin and starch according to this disclosure can be prepared, for example, by solution casting of an aqueous solution or mixture comprising polyvinyl alcohol resin and starch. It is generally desirable to prepare the aqueous solution or mixture under conditions sufficient to provide a substantially or completely homogeneous solution or mixture. For example, heating the starch-containing mixture can promote the gelatinization and dissolution of the starch. Generally, conditions including, but not limited to, temperature, mixing time, shear, or any combination thereof, can be adjusted to provide a substantially or completely homogeneous solution or mixture.

[0119] Mixed aqueous solutions or mixtures may contain entrained air. Solution casting containing entrained air may cause bubble formation in the cast film, which may be undesirable. Solution casting processes may include a degassing step of the aqueous solution or mixture prior to casting to allow or accelerate the dissipation of entrained air from the solution or mixture and reduce or eliminate bubble formation in the cast film. The degassing step may include heating the solution or mixture, for example at about 90°C for at least 12 hours, optionally under reduced pressure.

[0120] There are no particular limitations on the solids content of the aqueous solution or mixture. For solution casting of the membrane according to this disclosure, the solids content (i.e., non-aqueous content) of the aqueous solution or mixture, by weight, can be about 10%, or about 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%, or within a range formed by any such value as endpoints. As the solids content decreases, the compatibility of polyvinyl alcohol with starch generally increases because more polyvinyl alcohol and starch can dissolve in water. However, as the amount of water increases, the time and energy required to dry the membrane generally increase. Therefore, while a solids content of less than about 10% can be used to improve compatibility and solubility, such a concentration is impractical when scaled up to a commercial process due to time and energy costs.

[0121] In films, aqueous solutions, or mixtures containing polyvinyl alcohol (PVA) resin and starch, there are no particular limitations on the ratio of PVA resin to starch. For example, the ratio can range from about 99:1 to about 1:99, or about 95:5 to about 5:95, or about 90:10 to about 10:90, or about 80:20 to about 20:80, or about 70:30 to about 30:70, or about 60:40 to about 40:60. The compatibility of PVA resin and starch in aqueous solutions or mixtures may be affected by the ratio of PVA resin to starch. Generally, it is not intended to be theoretically constrained to assume that in compositions in which one of starch or PVA constitutes substantially all of the molding material (e.g., compositions having at least 90% PVA (i.e., no more than 10% starch) or at least 90% starch (i.e., no more than 10% PVA)), starch and PVA will exhibit good or complete compatibility, applicable to any combination of starch and PVA. However, not intended to be theoretically constrained, it is believed that when the amount of a small amount of film-forming material (i.e., starch or polyvinyl alcohol) increases and the relative amounts approach the 50 / 50 boundary, the incompatibility between starch and polyvinyl alcohol will become apparent.

[0122] Not intended to be theoretically constrained, the preparation of an aqueous solution or mixture for manufacturing a film according to the present disclosure by solution casting may include: adding starch and optionally one or more minor components to a salt-containing aqueous solution; heating the resulting mixture and stirring for a sufficient time, for example, in a temperature range of 65–80°C, to substantially gelatinize or dissolve the starch; adding a polyvinyl alcohol resin and stirring while maintaining the temperature range of 65–80°C for a sufficient time to dissolve the polyvinyl alcohol copolymer; and optionally degassing the resulting solution or mixture.

[0123] Water-soluble products

[0124] Membranes can be used to produce articles and / or bags containing compositions, such as cleaning compositions. The compositions contained in the bags can take any form, such as powders, gels, pastes, liquids, tablets, or any combination thereof. Membranes can also be used for any other applications requiring improved wet processing and low cold water residue. The membrane forms at least one sidewall of the article and / or bag, optionally forms the entire article and / or bag, and preferably forms the outer surface of at least one sidewall.

[0125] The membranes described herein can also be used to manufacture articles and / or bags having two or more compartments, said compartments and / or bags being made of the same membrane or in combination with membranes of other polymeric materials. Additional membranes can be obtained, for example, by casting, blow molding, extrusion, or blow extrusion of the same or different polymeric materials, as known in the art. Polymers, copolymers, or derivatives thereof suitable for use as additional membranes may include polyvinyl alcohol, polyvinylpyrrolidone, polyepoxides, polyacrylic acid, cellulose, cellulose ethers, cellulose esters, cellulose amides, polyvinyl acetate, polycarboxylic acids and salts, polyamino acids or peptides, polyamides, polyacrylamide, maleic acid / acrylic acid copolymers, polysaccharides including starch and gelatin, and natural gums such as xanthan gum and carrageenan. For example, polymers may be selected from polyacrylate and water-soluble acrylate copolymers, methylcellulose, sodium carboxymethyl cellulose, dextrin, ethylcellulose, hydroxyethylcellulose, hydroxypropyl methylcellulose, maltodextrin, polymethyl methacrylates, and combinations thereof, or selected from polyvinyl alcohol, polyvinyl alcohol copolymers and hydroxypropyl methylcellulose (HPMC), and combinations thereof. For example, as described above, the polymer level in the small package material (e.g., the PVOH copolymer described above) can be at least 60%.

[0126] The articles and / or bags disclosed herein may include at least one sealed compartment. Therefore, the articles and / or bags may contain a single compartment or multiple compartments. Water-soluble bags or pouches may be formed from two layers of water-soluble polymer films sealed at the interface, or from a single film that folds itself and seals. One or both films may include the aforementioned PVOH membrane. The film defines the internal article and / or bag container volume containing any desired composition for release into an aqueous environment.

[0127] There are no particular restrictions on the volume of the bag / container. The volume of the bag / container can be, for example, 25 mL or less. The volume of the bag / container can be less than 25 mL. The volume of the bag / container can be less than 50 mL.

[0128] There are no particular limitations on the compositions used in the bag. For bags comprising multiple compartments, each compartment may contain the same and / or different compositions, including but not limited to automatic dishwasher (ADW) compositions. Furthermore, the compositions may take any suitable form, including but not limited to liquids, solids, and combinations thereof (e.g., solids suspended in a liquid). The bag may comprise a first compartment, a second compartment, and a third compartment, each containing a different first, second, and third composition, respectively. Liquid detergents are particularly envisioned.

[0129] The compartments of a multi-compartment article and / or bag may have the same or different sizes and / or volumes. The compartments of the multi-compartment article and / or bag of the present invention may be separated or combined in any suitable manner. A second and / or third and / or subsequent compartment may be stacked on top of a first compartment. A third compartment may be stacked on top of a second compartment, which in turn is stacked on top of the first compartment in a sandwich configuration. Alternatively, the second and third compartments may be stacked on top of the first compartment. However, it is also equally contemplated that the first, second, and optionally third compartments, as well as subsequent compartments, may be attached to each other in a side-by-side relationship. The compartments may be packaged in a string, with each compartment individually separable by perforated thread. Thus, the end user can individually tear off each compartment from the remainder of the string, for example, to pre-treat or post-treat the fabric with the composition from the compartments. The first compartment may be surrounded by at least the second compartment, for example, in a tire and rim configuration or a bag-in-bag configuration.

[0130] The articles and / or bags disclosed herein may comprise one or more different films. For example, for a single-compartment pouch, the pouch may be made of one wall that folds itself and seals at the edges, or alternatively, two walls that are sealed together at the edges. For multi-compartment pouches, the articles and / or bags may be made of one or more films, such that any given pouch compartment may comprise a wall made of a single film or multiple films with different compositions. Multi-compartment articles and / or bags may comprise at least three walls: an outer upper wall; an outer lower wall; and a partition wall. The outer upper wall and outer lower wall are generally opposite each other and form the exterior of the article and / or bag. The partition wall is inside the article and / or bag and is fixed to the generally opposite outer wall along a sealing line. The partition wall divides the interior of the multi-compartment article and / or bag into at least a first compartment and a second compartment.

[0131] A single compartment or multiple sealed compartments may contain the composition. Multiple compartments may each contain the same or different compositions. The composition is selected from liquids, solids, or combinations thereof.

[0132] This disclosure provides a unit-dose article comprising at least one compartment and optionally a composition contained within said compartment, wherein at least one wall of said compartment comprises a water-soluble membrane of this disclosure.

[0133] Products and / or bag contents

[0134] Generally, the water-soluble articles of this disclosure may contain household care products, personal care products, or non-household care products. Unit-dosage articles may include a composition contained in a compartment, and said composition may contain an oxidizing agent. The oxidizing agent may contain hypochlorite, chloramine, isocyanurate chloride, isocyanurate bromide, chlorate, bromate, perchlorate, perbromate, calcium hydroxide, calcium chloride, percarbonate, perborate, periodate, persulfate, permanganate, chromate, dichromate, nitrate, nitrite, peroxide, peroxide ketone, peroxy acid, inorganic acid, or combinations thereof. The oxidizing agent may contain hypochlorite, chloramine, isocyanurate chloride, calcium hydroxide, calcium chloride, percarbonate, perborate, persulfate, permanganate, peroxide, peroxy acid, or combinations thereof.

[0135] Methods of manufacturing products

[0136] Articles such as bags or pouches can be manufactured using any suitable equipment and methods. For example, individual compartment bags can be manufactured using vertical filling, horizontal filling, or rotary drum filling techniques commonly known in the art. Such processes can be continuous or intermittent. The membrane can be damped and / or heated to increase its ductility. The method may also involve using a vacuum to draw the membrane into a suitable mold. Once the membrane is on the horizontal portion of the surface, the vacuum drawing the membrane into the mold can be applied for about 0.2 seconds to about 5 seconds, or about 0.3 seconds to about 3 seconds, or about 0.5 seconds to about 1.5 seconds. For example, this vacuum can enable it to provide a negative pressure in the range of 10 mbar to 1000 mbar or in the range of 100 mbar to 600 mbar.

[0137] Depending on the required bag size, the molds used to manufacture small bags can have any shape, length, width, and depth. The size and shape of the molds can also differ if desired. For example, the final bag volume can be from about 5 mL to about 300 mL, or from about 10 mL to 150 mL, or from about 20 mL to about 100 mL, and the mold size can be adjusted accordingly.

[0138] thermoforming

[0139] A thermoformable film is a film that can be shaped by applying heat and force. Thermoforming a film is the process of heating the film, shaping it (e.g., in a mold), and then cooling the film so that it retains its shape, such as that of the mold. Heat can be applied using any suitable means. For example, the film can be directly heated by passing it under a heating element or through hot air before or once it is supplied to a surface. Alternatively, the film can be indirectly heated, for example, by heating the surface or applying a hot article to the film. The film can be heated using infrared light. The film can be heated to temperatures in the range of about 50°C to about 150°C, about 50°C to about 120°C, about 60°C to about 130°C, about 70°C to about 120°C, or about 60°C to about 90°C. The film can be heated to temperatures ranging from about 30°C to about 100°C, or about 40°C to about 100°C, or about 50°C to about 100°C, or about 60°C to about 100°C, or about 30°C to about 90°C, or about 40°C to about 90°C, or about 50°C to about 90°C. The film can also be heated to temperatures ranging from about 30°C to about 80°C, or about 40°C to about 80°C, or about 50°C to about 80°C, or about 60°C to about 80°C, or about 30°C to about 70°C, or about 30°C to about 60°C, or about 30°C to about 50°C. Thermoforming can be performed through any one or more of the following processes: manually covering a heat-softened film onto a mold, or pressure-induced forming of a softened film into a mold (e.g., vacuum forming), or automatically feeding a fresh extruded sheet with an accurately known temperature at high speed to a forming and trimming station, or automated placement, insertion, and / or pneumatic stretching and pressurizing of the film.

[0140] Alternatively, the membrane can be wetted by any suitable means, such as directly by spraying a wetting agent (including water, a solution of the membrane composition, a plasticizer for the membrane composition, or any combination of the foregoing) onto the membrane before or once it is supplied to the surface, or indirectly by wetting the surface or by applying a wet article to the membrane.

[0141] Once the film is heated and / or wetted, it can preferably be drawn into a suitable mold using a vacuum. The filling of the molding film can be accomplished using any suitable means. The preferred method will depend on the product form and the required filling speed. The molding film can be filled using in-line filling technology. The filled open pouches can then be sealed using a second film by any suitable method, thus forming a bag. This can be done simultaneously in a horizontal position and with continuous, constant movement. Sealing can be accomplished by continuously supplying a second film, preferably a water-soluble film, above and over the open pouches, and then preferably sealing the first and second films together, typically in the area between the molds and thus between the pouches.

[0142] Sealing of water-soluble products

[0143] Any suitable sealing package and / or its individual compartments can be used. Non-limiting examples of such means include heat sealing, solvent welding, solvent or wet sealing, and combinations thereof. Typically, only the area to be sealed is treated with heat or solvent. Heat or solvent can be applied by any method, typically applied to the sealing material, and typically only to the area to be sealed. If solvent or wet sealing or welding is used, it may be preferable to also apply heat. Preferred wet or solvent sealing / welding methods involve selectively applying solvent to the area between molds, or to the sealing material, by spraying or printing this solvent onto these areas, and then applying pressure to these areas to form a seal. Alternatively, the solvent can be applied non-selectively to the sealing material, for example, to the entire surface of the sealing material, and then sealed by applying pressure to the area between molds. For example, sealing rollers and belts (optionally also provided with heat) can be used.

[0144] The inner membrane can be sealed to the outer membrane using a solvent sealant. The sealing solution is generally an aqueous solution. The sealing solution may contain water. The sealing solution may contain water and may further include one or more diols and / or glycols, such as 1,2-ethylene glycol (ethylene glycol), 1,3-propanediol, 1,2-propanediol, 1,4-butanediol (tetramethylene glycol), 1,5-pentanediol (pentamethylene glycol), 1,6-hexanediol (hexamethylene glycol), 2,3-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, various polyethylene glycols (e.g., diethylene glycol, triethylene glycol), and combinations thereof. The sealing solution may contain erythritol, threitol, araitol, xylitol, ribitol, mannitol, sorbitol, galactitol, fucitol, idoterol, inositol, lemmierol, sucralose, maltitol, and lactitol.

[0145] The sealing solution can be applied in any amount suitable for adhesion to both the inner and outer membranes to the interface region of the inner membrane. As used herein, the term "coating weight" refers to the amount of sealing solution applied to the membrane, expressed in grams per square meter of membrane solution. Generally, when the coating weight of the sealing solvent is too low, the membrane does not adhere properly, and the risk of bag failure at the seams increases. Furthermore, when the coating weight of the sealing solvent is too high, the risk of solvent migration from the interface region increases, thereby increasing the likelihood of etch pitting potentially forming on the sides of the bag. A coating weight window refers to the range of coating weights that can be applied to a given membrane while maintaining good adhesion and avoiding etch pitting. A wide coating weight window is desirable because a wider window can provide a robust seal over a wide operating range. A suitable coating weight window is at least about 3 g / m². 2 or at least about 4 g / m 2 or at least about 5 g / m2 or at least about 6 g / m 2 .

[0146] PVOH / starch compatibility

[0147] Polyvinyl alcohol (PVA) resins and starch may exhibit low compatibility with each other. Specifically, PVA homopolymers may exhibit low compatibility with starch. This low compatibility between PVA resins and starch can be represented, for example, by phase separation in an aqueous mixture containing PVA resins and starch. This low compatibility may hinder the formation of a homogeneous film comprising PVA and starch. Solution casting of a phase-separated aqueous mixture containing PVA resins and starch (e.g., an aqueous mixture having a PVOH-enriched aqueous phase and a starch-enriched aqueous phase) onto a casting surface may produce a solution layer with PVOH-enriched and starch-enriched structural domains, which may form a non-homogeneous film upon drying. Furthermore, phase separation between PVA resins and starch occurring within the solution-cast layer before it is completely dried may introduce PVOH-enriched and / or starch-enriched structural domains into the resulting solution-cast film.

[0148] As determined by the compatibility testing methods described herein, the compatibility ratio between polyvinyl alcohol resin and starch in an aqueous solution or mixture can be less than about 40%, or less than about 35%, or less than about 30%, or less than about 25%, or less than about 20%, or less than about 15%, or less than about 10%. Generally, if the compatibility ratio is less than about 10%, then the aqueous solution or mixture can be used to manufacture films by solution casting. If the compatibility ratio is greater than about 10%, then improving the compatibility between polyvinyl alcohol resin and starch for manufacturing films by solution casting may be desirable.

[0149] Methods for attempting to improve the compatibility between polyvinyl alcohol resin and starch in aqueous solutions or mixtures may include diluting the aqueous solution or mixture and / or adjusting the levels of minor components (e.g., plasticizers, surfactants). However, these methods are not without drawbacks. Diluting the aqueous solution or mixture may increase membrane manufacturing costs and / or reduce yield due to the energy and time required to remove additional moisture. Adjusting the levels of minor components may adversely affect the performance of the resulting membrane.

[0150] Salt Addition

[0151] Inorganic and organic ions can be classified according to their Hofmeister sequence (or solvation sequence), a classification based on their ability to influence the solubility of dissolved species. Generally, ions that increase the order and structure of water by enhancing hydrogen bonding are characterized as "kosmotropic," while ions that decrease the order and structure of water by disrupting hydrogen bonding are characterized as "chaotropic." For aqueous solutions or mixtures containing one or more dissolved polymers, the addition of kosmotropic ions can compete with the dissolved polymers for water, thus reducing the amount of water available for interaction with the polymer and promoting intrapolymer interactions, thereby reducing the polymer's water solubility (i.e., "salting"). Conversely, the addition of chaotropic ions can increase the polymer's water solubility (i.e., "salting"). A partial list of cations classified according to increased chaotropic levels is NH4+. + (Most hydrophilic), K + Na + Li + Mg 2+ Ca 2+ Guanidine (the most dissociated liquid).

[0152] As shown in the following examples, ions that will be characterized as having high ionization levels (e.g., Mg) 2+ Adding ions (or guanidines) to aqueous mixtures containing polyvinyl alcohol (PVA) and starch increases the compatibility of PVA and starch. Not intended to be theoretically constrained, it is believed that adding ions characterized as having a high degree of liquid ionization can improve the compatibility of PVA resins with starch, for example, by increasing the water solubility of one or both polymers and / or by disrupting intramolecular hydrogen bonding, and thus promoting interactions between PVA resins and starch (such as hydrophobic interactions or van der Waals interactions). Furthermore, it is thought that adding salts may interfere with starch precipitation, making it less likely for dissolved starch to form crystal structures that may have poor compatibility with PVA resins upon cooling.

[0153] Test methods

[0154] Dissolution and disintegration test (MSTM 205)

[0155] According to MonoSol test method 205 (MSTM 205), a membrane can be characterized by or tested for dissolution and disintegration times, as known in the art. See, for example, U.S. Patent No. 7,022,656. Apparatus and Materials:

[0156] 600 mL beaker

[0157] Magnetic stirrer (Labline model 1250 or equivalent)

[0158] Magnetic stirring rod (5 cm)

[0159] Thermometer (0 to 100℃ ± 1℃)

[0160] Template, stainless steel (3.8 cm × 3.2 cm)

[0161] Timer (0-300 seconds, accurate to the nearest second)

[0162] Polaroid 35 mm slider mount (or equivalent)

[0163] MonoSol 35 mm slider mount retainer (or equivalent)

[0164] distilled water

[0165] All membranes to be tested were conditioned at 23°C / 35% relative humidity for at least 24 hours. For each membrane to be tested, three test samples were cut from the membrane sample, i.e., 3.8 cm × 3.2 cm samples. If cut from the membrane mesh, the samples should be cut from areas of the mesh that are evenly spaced along the transverse direction of the mesh. Each test sample was then analyzed using the following procedure.

[0166] Each sample is locked in a separate 35 mm slider mount.

[0167] Fill the beaker with 500 mL of distilled water. Measure the water temperature with a thermometer and, if necessary, heat or cool the water to maintain the temperature at approximately 5°C (approximately 41°F).

[0168] Mark the height of the water column. Place the magnetic stirrer on the holder base. Place the beaker on the magnetic stirrer and add the magnetic stirring rod to the beaker. Turn on the stirrer and adjust the stirring speed until a vortex is formed at approximately one-fifth of the water column height. Mark the vortex depth.

[0169] Secure the 35 mm slider mount to the alligator clips of the 35 mm slider mount holder, ensuring the long end of the slider mount is parallel to the water surface. The holder's depth adjuster should be set so that, upon lowering, the end of the clip will be 0.6 cm below the water surface. One of the short sides of the slider mount should be flush against the side of the beaker, while the other short side should be positioned directly above the center of the stir bar, ensuring the membrane surface is perpendicular to the water flow.

[0170] In one operation, the fixed slider is lowered and clamped into the water, and a timer is started. Disintegration occurs when the membrane ruptures. As all visible membrane fragments are released from the slider mount, the slider is raised from the water while monitoring for undissolved membrane fragments in the solution continues. Dissolution occurs when all membrane fragments are no longer visible and the solution becomes clear.

[0171] The results should include the following: complete sample identification; individual and average disintegration and dissolution times; and the water temperature at which the sample was tested.

[0172] The membrane disintegration time (I) and membrane dissolution time (S) can be corrected to the standard or reference membrane thickness using the exponential algorithms shown in Equations 1 and 2 below, respectively.

[0173] I 校正 = I 测得 x (Reference thickness / Measured thickness) 1.93 [1]

[0174] S 校正 = S 测得 x (Reference thickness / Measured thickness) 1.83 [2]

[0175] The membrane's disintegration and dissolution in brine were also tested. For these experiments, the MSTM-205 method was performed as described above, except that the membrane was immersed in 500 mL of a 3.5% sodium chloride solution in distilled water at 5°C, instead of immersing it in 500 mL of distilled water at 5°C. The membrane's disintegration and dissolution times in brine were determined using the same criteria used to determine the disintegration and dissolution times in water.

[0176] DSC method (MSTM 122)

[0177] To avoid weight loss during heating, use a TA Instruments Q2000 Differential Scanning Calorimeter (DSC) or equivalent with 50 mL / min nitrogen purging and a TZERO aluminum sealing disc (available from TA Instruments). Cut the membrane sample to be tested into small pieces to provide approximately 3–5 mg of total sample suitable for the disc (e.g., approximately 3 stacked, cut membrane pieces). The sample was equilibrated at -80°C and then subjected to DSC testing as follows: (1) the sample was heated to 75°C at a rate of 10°C / min to begin generating a first DSC heating curve; (2) the sample was held at 75°C for 10 minutes; (3) the sample was heated from 75°C to 200°C at a rate of 10°C / min to complete the first DSC heating curve; (4) the sample was cooled to -75°C at a rate of -5°C / min to generate a DSC cooling curve; and optionally (5) the sample was reheated to 200°C at a rate of 10°C / min to generate a second DSC heating curve. After generating the curves, the transition, melting, and crystallization attributable to the glass transition were determined; the glass transition temperature, melting temperature, and crystallization temperature (Tg, Tm, and Tc, respectively) were determined; and the enthalpy of melting or crystallization was determined by standard calorimetry analysis. Optionally, the second glass transition temperature (Tg2) of the sample can be determined from the reheating step (3), corresponding to the glass transition of the film after the removal of residual moisture (i.e. during the first heating step).

[0178] Tensile strength test

[0179] Water-soluble membranes characterized by tensile strength (TS) testing or tested for tensile strength are analyzed as follows. The procedure involves determining tensile strength according to ASTM D 882 (“Standard Test Method for Tensile Properties of Thin Plastic Sheets”) or its equivalent. An INSTRON tensile testing apparatus (Model 5544 tensile tester or equivalent) is used to collect membrane data. For each measurement, at least three test specimens are tested in machine orientation (MD), where applicable, and each specimen is cut with a reliable cutting tool to ensure dimensional stability and reproducibility. The membranes under test are conditioned for at least 24 hours at 23 ± 2.0 °C and 35 ± 5% RH; tensile strength testing is also performed at 23 ± 2.0 °C and 35 ± 5% RH. For tensile strength, samples of a single membrane sheet, 1” wide (2.54 cm) and 76 μm thick, were prepared. The samples were then transferred to an INSTRON tensile testing machine for testing, with exposure minimized in an environment of 35% relative humidity. The tensile testing machine, equipped with a 500 N manometer, was prepared and calibrated according to the manufacturer's instructions. The correct grip and facet (INSTRON grip, model 2702-032 facet, rubber-coated and 25 mm wide, or equivalent) were installed. The samples were mounted in the tensile testing machine and analyzed to determine the tensile strength (i.e., the stress required to cause the membrane to break).

[0180] Young's modulus is determined based on the slope of a linear fit of stress-strain data within the 1-3% strain range.

[0181] Elongation at break test

[0182] The procedure involves determining elongation at break based on ASTM D 882 (“Standard Test Method for Tensile Properties of Thin Plastic Sheets”) or its equivalent. INSTRON is used. ® Tensile testing equipment (Model 5544 tensile tester or equivalent) was used to collect membrane data. For each measurement, at least three test samples were tested in the machine orientation (MD), if applicable, and each sample was cut with a reliable cutting tool to ensure dimensional stability and reproducibility. The membranes under test were conditioned for at least 24 hours at 23 ± 2.0 °C and 35 ± 5% RH; elongation at break testing was also performed at 23 ± 2.0 °C and 35 ± 5% RH. For elongation at break determination, a single membrane sheet sample 1” wide (2.54 cm) with a thickness of 1.4 ± 0.15 mils (approximately 35.6 ± 3.8 μm) was prepared. The sample was then transferred to INSTRON. ®The test was conducted on a tensile testing machine, minimizing exposure to an environment with 35% relative humidity. The tensile testing machine was prepared according to the manufacturer's instructions, equipped with a 500N force sensor, and calibrated. The correct grip and face were installed. ® The grip has a surface designated 2702-032, which is coated with rubber and has a width of 25 mm (or equivalent). The sample is mounted in a tensile testing machine and analyzed to determine the elongation at break (i.e., Young's modulus, where applicable).

[0183] Compatibility testing

[0184] The compatibility of the two polymers is assessed by measuring the degree of phase separation (if any) in an aqueous mixture containing the two polymers and optionally one or more additives. Optionally, in the presence of one or more additives, the sample used to assess the compatibility of polyvinyl alcohol resin and starch is prepared as follows: An aqueous solution optionally containing one or more additives is prepared by mixing the additives in water and, if necessary, heating at a temperature of up to 80°C to dissolve the additives. Starch is added at a solution temperature of 80°C, followed by mixing at 80°C for 75 minutes. Polyvinyl alcohol resin is then added, followed by mixing at 80°C for 30 minutes. The final aqueous mixture has a solids content of 30 wt.% (i.e., 30% non-aqueous content). The aqueous mixture is transferred to a loosely sealed 1-L HDPE tank with vertical sides and held at 90°C for 16 hours to degas. If no significant separation layer is observed in the aqueous mixture after 16 hours, the polyvinyl alcohol resin and starch are considered completely compatible. If two distinctly separated layers appear after 16 hours of holding, the compatibility ratio (expressed as a percentage) of polyvinyl alcohol resin to starch is defined as SH / FH, where SH (in centimeters) is the vertical height of the layer with the lower volume in the container, and FH (in centimeters) is the vertical distance from the bottom of the container to the air / sample interface. The layer with the lower volume can be either the bottom or top layer. The compatibility ratio can range from greater than 0% to 50%. Generally, a lower compatibility ratio indicates less phase separation and therefore higher compatibility.

[0185] Example

[0186] Example 1

[0187] Aqueous mixtures 1a–1c containing PVOH polymer, starch, plasticizer, minor components, and optionally magnesium chloride or guanidine chloride were prepared according to the formulations in Table 1. The amounts of each component are listed as the total resin content per 100 parts (i.e., PVOH + starch). The solids content (i.e., non-aqueous content) of each mixture is 30 wt% based on the total weight of the mixture. Preparation of the mixtures involved mixing at a temperature range of 65–80 °C for 75 minutes after the addition of starch to promote starch gelatinization and dissolution. The compatibility ratio of the PVOH polymer to starch in each mixture was evaluated according to compatibility testing methods.

[0188] Table 1.

[0189]

[0190] Adding 5.7 phr of salt (magnesium chloride or guanidine chloride) to the aqueous mixture improved the compatibility of PVOH with starch, as evidenced by the reduced compatibility ratio of the salt-containing blend compared to the salt-free blend (i.e., reduced phase separation). Increasing the amount of magnesium chloride in the mixture from 5.7 phr to 11.4 phr further improved the compatibility of PVOH with starch.

[0191] Example 2

[0192] Aqueous mixtures 2a–2d containing PVOH polymer, starch, plasticizer, other additives, and optionally magnesium chloride or guanidine chloride were prepared according to the formulations in Table 2. Preparation of the mixtures involved mixing at a temperature range of 65–80°C for 75 minutes after adding hydroxyethyl-modified starch to gelatinize and dissolve the starch. The amounts of each component are listed as the total resin content per hundred parts (i.e., PVOH + starch) in each mixture. The compatibility ratio of the PVOH polymer to starch in each mixture was evaluated according to compatibility testing methods. The aqueous mixture of Example 2 contains less plasticizer than the aqueous mixture of Example 1 (approximately 12 phr, compared to approximately 30–32 phr).

[0193] Table 2.

[0194]

[0195] An improvement in compatibility ratio was also observed after the addition of salt in the reduced plasticizer mixture of Example 2.

[0196] Not intended to be theoretically constrained, the addition of salt in aqueous mixtures may have a similar effect to increasing the plasticizer level. Compatibility ratios of salt-free mixtures (Examples 1a and 2a) indicate that PVOH / starch compatibility improved when the plasticizer level in the mixture was increased from 12.3 phr to 32.0 phr. Examples 2b and 2c show that similar improvements in PVOH / starch compatibility were achieved by adding 5.7 phr of salt (magnesium chloride or guanidine chloride) without changing the plasticizer level.

[0197] Since modifications and alterations made to adapt to specific operating requirements and environments will be obvious to those skilled in the art, this disclosure is not intended to be limited to the examples chosen for illustrative purposes and covers all changes and modifications that do not constitute a departure from the true spirit and scope of this disclosure.

[0198] Accordingly, the foregoing description has been provided for clarity of understanding only, and should not be construed as an unnecessary limitation, as modifications within the scope of this disclosure will be readily apparent to those skilled in the art.

[0199] Throughout this specification, unless otherwise described, when a compound, composition, article, method, or process is described as including components, steps, or materials, it is contemplated that the composition, process, or apparatus may also comprise, consist substantially of, or be composed of any combination of said components or materials.

Claims

1. A water-soluble membrane comprising: Polyvinyl alcohol resin, Starch, and Salt, The amount of salt present in the membrane is sufficient to improve the compatibility ratio of the polyvinyl alcohol resin to the starch compared to the compatibility ratio of the polyvinyl alcohol resin to the starch in the absence of the salt, as determined by a compatibility test method.

2. The water-soluble membrane according to claim 1, wherein the ratio of polyvinyl alcohol resin to starch in the membrane is in the range of about 95:5 to about 5:95, or about 90:10 to about 10:90, or about 80:20 to about 20:80, or about 70:30 to about 30:70, or about 60:40 to about 40:

60.

3. The water-soluble membrane according to claim 1 or 2, wherein the salt is selected from ammonium salts, lithium salts, sodium salts, potassium salts, calcium salts, magnesium salts, manganese salts, barium salts, iron salts, salts containing organic cations, and mixtures thereof.

4. The water-soluble membrane according to claim 3, wherein the organic cation is guanidine.

5. The water-soluble membrane according to any one of the preceding claims, wherein the salt is selected from chloride salts, bromide salts, acetate salts, sulfate salts, nitrate salts, phosphate salts, and mixtures thereof.

6. The water-soluble membrane according to claim 5, wherein the salt comprises a chloride salt.

7. The water-soluble membrane according to any one of the preceding claims, wherein the salt is present in the water-soluble membrane in an amount ranging from about 1 phr to about 30 phr, or about 2 phr to about 25 phr, or about 3 phr to about 20 phr, or about 5 phr to about 15 phr.

8. The water-soluble film according to any one of the preceding claims, wherein the polyvinyl alcohol resin comprises a polyvinyl alcohol homopolymer, a polyvinyl alcohol copolymer, or a mixture thereof.

9. The water-soluble membrane according to claim 8, wherein the polyvinyl alcohol resin comprises a polyvinyl alcohol homopolymer.

10. The water-soluble membrane according to any one of the preceding claims, wherein the polyvinyl alcohol resin is present in the membrane in an amount ranging from about 5 wt.% to about 95 wt.%, or about 10 wt.% to about 90 wt.%, or about 20 wt.% to about 80 wt.%, or about 30 wt.% to about 70 wt.% based on the total weight of the membrane.

11. The water-soluble membrane according to any one of the preceding claims, wherein at least a portion of the polyvinyl alcohol resin is bio-based.

12. The water-soluble membrane according to any one of the preceding claims, wherein the starch is selected from unmodified starch, starch modified with nonionic groups, starch modified with anionic groups, starch modified with cationic groups, and mixtures thereof.

13. The water-soluble membrane according to claim 12, wherein the starch comprises starch modified with cationic groups.

14. The water-soluble membrane of claim 12, wherein the starch comprises starch modified with nonionic groups.

15. The water-soluble membrane according to claim 14, wherein the nonionic modified starch comprises hydroxyethyl modified starch, hydroxypropyl modified starch, or octenyl succinic anhydride modified starch.

16. The water-soluble membrane according to any one of the preceding claims, wherein the starch is present in the membrane in an amount ranging from about 5 wt.% to about 95 wt.%, or about 10 wt.% to about 90 wt.%, or about 20 wt.% to about 80 wt.%, or about 30 wt.% to about 70 wt.% based on the total weight of the membrane.

17. The water-soluble film according to any one of the preceding claims, further comprising a plasticizer.

18. The water-soluble film according to claim 17, wherein the plasticizer is selected from the group consisting of polyols, sugar alcohols, polyethers, amines, and mixtures thereof.

19. The water-soluble membrane according to claim 18, wherein the plasticizer is selected from glycerol, diglycerol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, up to 400 MW of polyethylene glycol, neopentyl glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, polypropylene glycol, 2-methyl-1,3-propanediol, trimethylolpropane, polyether polyol, isomaltulose, maltitol, sorbitol, xylitol, erythritol, calendula alcohol, galactitol, pentaerythritol, mannitol, ethanolamine, and mixtures thereof.

20. The water-soluble membrane according to any one of claims 17 to 19, wherein the plasticizer is present in the water-soluble membrane in an amount ranging from about 10 phr to about 50 phr.

21. The water-soluble membrane according to any one of the preceding claims, wherein the membrane comprises one or more additives selected from: fillers, surfactants, anti-blocking agents, antioxidants, defoamers, bleaching agents, irritants, other functional ingredients, and combinations thereof.

22. The water-soluble membrane according to any one of the preceding claims, wherein the membrane, when provided with a thickness of about 76 micrometers, has a dissolution time of less than 300 seconds, or less than 240 seconds, or less than 180 seconds, or less than 120 seconds at 5°C, as measured according to MonoSol test method MSTM 205.

23. A water-soluble article comprising a water-soluble film according to any one of the preceding claims.

24. An aqueous mixture comprising: Polyvinyl alcohol resin; starch; Salt; and water, The amount of salt present is sufficient to improve the compatibility ratio of the polyvinyl alcohol resin to the starch relative to that of the otherwise identical aqueous mixture without the salt, as determined by a compatibility test method.

25. The aqueous mixture of claim 24, wherein the ratio of polyvinyl alcohol resin to starch in the aqueous mixture is in the range of about 95:5 to about 5:95, or about 90:10 to about 10:90, or about 80:20 to about 20:80, or about 70:30 to about 30:70, or about 60:40 to about 40:

60.

26. The aqueous mixture according to claim 24 or 25, wherein the total solids content of the aqueous mixture is at least about 10 wt.%, or at least about 20 wt.%, or at least about 30 wt.%, or at least about 40 wt.%, based on the weight of the aqueous mixture.

27. The aqueous mixture according to any one of claims 24 to 26, wherein the compatibility ratio of the polyvinyl alcohol resin to the starch in the aqueous mixture is less than about 30%.

28. A method for making polyvinyl alcohol resin and starch compatible in an aqueous mixture, the method comprising adding salt to the aqueous mixture, wherein the amount of salt added is sufficient to improve the compatibility ratio of the polyvinyl alcohol resin to the starch in the aqueous mixture relative to the compatibility ratio of the polyvinyl alcohol resin to the starch in an otherwise identical aqueous mixture without the salt, as determined by a compatibility testing method.

29. The method of claim 28, wherein the salt is selected from ammonium salts, lithium salts, sodium salts, potassium salts, calcium salts, magnesium salts, manganese salts, barium salts, iron salts, salts containing organic cations, and mixtures thereof.

30. The method of claim 29, wherein the organic cation is guanidine.

31. The method according to any one of claims 28 to 30, wherein the salt is selected from chloride salts, bromide salts, acetate salts, sulfate salts, nitrate salts, phosphate salts, and mixtures thereof.

32. The method of claim 31, wherein the salt comprises a chloride salt.

33. The method according to any one of claims 28 to 32, wherein the amount of salt added to the aqueous mixture ranges from about 1 phr to about 30 phr, or about 2 phr to about 25 phr, or about 3 phr to about 20 phr, or about 5 phr to about 15 phr.

34. The method according to any one of claims 28 to 33, wherein the polyvinyl alcohol resin comprises a polyvinyl alcohol homopolymer, a polyvinyl alcohol copolymer, or a mixture thereof.

35. The method of claim 34, wherein the polyvinyl alcohol resin comprises a polyvinyl alcohol homopolymer.

36. The method according to any one of claims 28 to 35, wherein the starch is selected from unmodified starch, starch modified with nonionic groups, starch modified with anionic groups, starch modified with cationic groups, and mixtures thereof.

37. The method of claim 36, wherein the starch comprises starch modified with nonionic groups.

38. The method of claim 37, wherein the nonionic modified starch comprises hydroxyethyl modified starch.

39. The method of claim 36, wherein the starch comprises starch modified with cationic groups.

40. The method according to any one of claims 28 to 39, wherein the starch is present in the aqueous mixture in an amount ranging from about 5 phr to about 80 phr, or about 10 phr to about 60 phr, or about 20 phr to about 50 phr, or about 30 phr to about 45 phr.

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