Hydrolytic film containing cellulose and method for producing same

Abstract

Disclosed is a cellulose-containing water-dissociable film according to various embodiments of the present invention to achieve the above-mentioned technical problem. The water-dissociable film may be characterized by containing Pulullan, carboxymethyl cellulose, and cellulose.

Description

Technical Field

[0001] This invention relates to a water-dissociable film, and more specifically, to an environmentally friendly water-dissociable film containing cellulose and a method for manufacturing the same, which can replace existing water-dissociable films containing polyvinyl alcohol (PVA). Background Technology

[0002] In recent years, the demand for water-dissociable (water-soluble) films has been increasing across various industrial sectors. Water-dissociable films possess the property of rapidly dissolving in water under specified conditions without leaving any residue in the environment, thus finding wide application in detergent packaging materials, pharmaceutical capsules, food packaging, industrial coatings, and many other fields. Especially given that existing plastic films have been identified as a major cause of environmental pollution, research into biodegradable or water-dissociable film materials is actively underway.

[0003] Currently, the most widely used water-dissociable film material is polyvinyl alcohol (PVA). PVA possesses excellent water solubility and mechanical strength, and exhibits a relatively rapid degradation rate after dissolution, thus finding widespread application across various industrial sectors. For example, many products, such as laundry detergent pods, pesticide packaging, water-soluble medical bags, and food packaging materials, are manufactured using PVA-based films.

[0004] However, recent research indicates that while polyvinyl alcohol (PVA) is water-soluble, it has limitations in terms of biodegradability. Specifically, it suggests the possibility that it cannot be completely degraded during wastewater treatment, remaining as fine polymers and accumulating in the environment. According to reports from the U.S. Environmental Protection Agency (EPA) and several research institutions, approximately 75% of PVA-based films are not completely degraded after wastewater treatment and are ultimately released into the natural environment. For this reason, the European Union (EU), the United States, and other major countries are strengthening environmental regulations to restrict the use of PVA-based films.

[0005] Therefore, it is necessary to develop an alternative material that can simultaneously satisfy the requirements of water solubility and mechanical strength without using polyvinyl alcohol. However, existing research on alternative materials has many limitations. For example, films based on natural polymers (such as cellulose, starch, chitosan, etc.) have excellent water solubility, but their mechanical strength is lower than that of polyvinyl alcohol, resulting in brittleness and easy breakage. Conversely, some synthetic polymers, while possessing excellent mechanical strength, have low water solubility, leading to problems such as long dissolution times or the presence of residues.

[0006] In particular, from a technical standpoint, preparing water-dissociable films without polyvinyl alcohol (PVA) is extremely difficult. PVA plays a crucial role in film formation, optimizing solution viscosity and aiding in the formation of uniform films. Therefore, to prepare films without PVA, three key factors must be addressed simultaneously: viscosity adjustment, ensuring the film's mechanical strength, and regulating water dissociation. Typically, when the viscosity of a natural polymer-based film is too low, it becomes water-like, making film formation impossible; when the viscosity is too high, gelation occurs, making it difficult to produce uniform films. Furthermore, weak bonding between water-soluble polymers can lead to easy tearing or a sharp decrease in mechanical strength.

[0007] Therefore, there is an urgent need to develop an alternative technology that can maintain similar levels of physical properties to existing polyvinyl alcohol-based films even without polyvinyl alcohol. In particular, with the increasing stringency of environmental regulations in recent years, there is a need to develop new environmentally friendly film materials that are fully biodegradable and do not produce microplastic emissions. To achieve this goal, the precise design of the film composition and manufacturing process is crucial.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Korean Patent Publication No. 10-2023-0020601 (February 13, 2023) Summary of the Invention

[0011] Technical issues

[0012] The technical problem to be solved by the present invention is to solve the above-mentioned problems and to provide an alternative film that overcomes the environmental limitations of polyvinyl alcohol (PVA)-based water-dissociable films and can maintain excellent water dissociability and mechanical strength even without polyvinyl alcohol.

[0013] The technical problems to be solved by the present invention are not limited to those mentioned above. Those skilled in the art to which this invention pertains can clearly understand other unmentioned problems from the following description.

[0014] Technical solution

[0015] A cellulose-containing hydrolytic membrane according to various embodiments of the present invention is disclosed to solve the above-mentioned problems. The hydrolytic membrane may be characterized in that it contains pullulan, carboxymethyl cellulose, and cellulose.

[0016] In alternative embodiments, the invention may be characterized in that, in the hydrolytic film, the content of carboxymethyl cellulose is in the range of more than 2 parts by weight and less than 20 parts by weight relative to 100 parts by weight of pullulan, and the content of cellulose is in the range of more than 2 parts by weight and less than 20 parts by weight relative to 100 parts by weight of pullulan.

[0017] In an alternative embodiment, the invention may be characterized in that the water-dissociable film is formed from a mixed solution with a viscosity in the range of 1500 centipoise (cps) to 6500 centipoise.

[0018] In an alternative embodiment, the present invention may be characterized in that the tensile strength of the water-dissociable film is in the range of 20 N or more to 50 N or less.

[0019] In an alternative embodiment, the invention may be characterized in that the hydrolytic film forms an intermolecular hydrogen bond network between the pullulan and the carboxymethyl cellulose.

[0020] In an alternative embodiment, the present invention may be characterized in that the hydrolytic film comprises: a main raw material comprising pullulan, carboxymethyl cellulose and cellulose; and an auxiliary raw material for adjusting the mechanical strength, flexibility and solubility of the film, wherein the content of the auxiliary raw material is less than 100 parts by weight relative to 100 parts by weight of the main raw material.

[0021] In alternative embodiments, the auxiliary ingredient may include at least one of carrageenan, cyclodextrin, sorbitol, and glycerin.

[0022] In an alternative embodiment, the invention may be characterized in that the water-dissociable film may contain an additional raw material, the additional raw material being a surfactant, in which case the final viscosity is in the range of more than 15,000 centipoise to less than 30,000 centipoise.

[0023] In another embodiment of the present invention, a method for manufacturing a hydrolytically soluble film comprising cellulose is disclosed. The method may include: the steps of manufacturing a mixed solution comprising pullulan, carboxymethyl cellulose, and cellulose; coating the mixed solution onto a plate; and drying the coated mixed solution to form a hydrolytically soluble film.

[0024] The effects of the invention

[0025] According to various embodiments of the present invention, a water-dissociable film can be provided that achieves similar viscosity and tensile strength to existing polyvinyl alcohol (PVA)-based films even without polyvinyl alcohol (PVA). Thus, it addresses the environmental problems associated with existing PVA-based films while maintaining the film's mechanical strength and processability.

[0026] Furthermore, the film of this invention is completely biodegradable and environmentally friendly, and will not cause environmental pollution such as microplastics even during wastewater treatment. Therefore, it can meet increasingly stringent global environmental regulations and can be used as a sustainable alternative material in various industrial sectors.

[0027] Furthermore, the physical properties of the film can be further improved by combining auxiliary materials as needed. For example, by adding specific plasticizers and crosslinking agents, the elasticity and durability of the film can be improved, and by adding viscosity modifiers, the processability during film formation can be enhanced. By adjusting this structure, there is the advantage of being able to optimize the physical properties of the film according to the intended purpose.

[0028] The effects of the present invention are not limited to those mentioned above. Those skilled in the art to which this invention pertains can clearly understand other effects not mentioned from the following description. Attached Figure Description

[0029] Various embodiments are now described with reference to the accompanying drawings, wherein similar reference numerals are used to generally refer to similar components. In the following embodiments, several specific details are set forth for illustrative purposes in order to provide a comprehensive understanding of more than one embodiment. However, it will be apparent that these embodiments can be practiced even without these specific details.

[0030] Figure 1 An exemplary flowchart illustrating a method for manufacturing a cellulose-containing hydrolytic thin film according to an embodiment of the present invention is shown.

[0031] Figure 2 This is an example diagram used to illustrate pullulan polysaccharide according to an embodiment of the present invention.

[0032] Figure 3 This is an example diagram used to illustrate carboxymethyl cellulose according to an embodiment of the present invention.

[0033] Figure 4 This is an example diagram used to illustrate cellulose according to an embodiment of the present invention.

[0034] Figure 5 Example diagram illustrating the manufacturing process of a cellulose-containing hydrolytic film according to an embodiment of the present invention.

[0035] Figure 6This is an example diagram used to illustrate a cellulose-containing hydrolytic thin film according to an embodiment of the present invention.

[0036] Figures 7 to 9 A diagram illustrating multiple thin films fabricated according to an embodiment of the present invention.

[0037] Figure 10 An example diagram illustrating the tensile stress-strain curve of a cellulose-containing hydrolytic film according to an embodiment of the present invention.

[0038] Figure 11 A diagram illustrating a film made by adding a surfactant to a water-dissociable film composition according to an embodiment of the present invention. Detailed Implementation

[0039] The following describes various embodiments and / or implementations in conjunction with the accompanying drawings. For illustrative purposes, several specific details are disclosed in the following description to provide a comprehensive understanding of more than one implementation. However, those skilled in the art will understand that these (multiple) implementations can be practiced even without these specific details. Specific exemplary embodiments of more than one implementation are described in detail in the following description and accompanying drawings. However, these embodiments are merely examples, and some of the various methods in the principles of multiple implementations may be utilized. The description is intended to cover all such embodiments and their equivalents. Specifically, the terms "embodiment," "example," "implementation," "example," etc., used in this specification should not be construed as any of the described embodiments or designs being superior or advantageous to other embodiments or designs.

[0040] Hereinafter, regardless of the reference numerals used, the same or similar structural elements will be assigned the same reference numerals, and redundant descriptions thereof will be omitted. Furthermore, when describing embodiments disclosed in this specification, if it is determined that a detailed description of related known technologies might obscure the subject matter of the disclosed embodiments, such a detailed description will be omitted. Additionally, the accompanying drawings are only for facilitating understanding of the embodiments disclosed in this specification, and the technical concepts disclosed in this specification are not limited to the drawings.

[0041] The objects, advantages, and technical structures for implementing the present invention will become apparent from the embodiments described in detail with reference to the accompanying drawings. In the description of the present invention, detailed descriptions of known properties or structures will be omitted if it is determined that such detailed descriptions might unnecessarily obscure the main points of the invention. Furthermore, the following terminology is defined in view of the properties in the present invention and may vary depending on the intentions or practices of the user, operator, etc.

[0042] However, the present invention is not limited to the embodiments disclosed below, but can be implemented in many different forms. These embodiments are only used to improve the present invention and to fully illustrate the scope of the invention to those skilled in the art, and the invention is defined only by the scope of the claims. Therefore, it should be defined based on the entire contents of this specification.

[0043] Water-dissociable (water-soluble) films are widely used in various industrial fields, especially in detergent packaging materials, food packaging, pharmaceutical capsules, and industrial coatings. Polyvinyl alcohol (PVA) is used as the main raw material for existing water-dissociable films. PVA possesses excellent film-forming properties and mechanical strength, thus providing a stable manufacturing process and superior performance.

[0044] However, despite its water solubility, polyvinyl alcohol (PVA) has been reported to be difficult to completely biodegrade in the environment. In particular, the demand for environmentally friendly alternatives to PVA is growing due to the potential release of partially undegraded PVA into the environment during wastewater treatment. Natural polymer-based films have thus been considered as a potential alternative, but existing natural polymer films suffer from low mechanical strength or poor processability, hindering their practical application.

[0045] The present invention aims to provide a water-dissociable film that can maintain similar viscosity and tensile strength to existing polyvinyl alcohol-based films even without polyvinyl alcohol. To this end, a method for manufacturing the film based on a specific composition is proposed.

[0046] The water-dissociable film of this invention is an environmentally friendly film configured to achieve similar mechanical strength and viscosity to existing polyvinyl alcohol (PVA)-based films even without PVA. The water-dissociable film of this invention is based on a cellulose-containing composition, with optimized composition ratios and preparation processes to facilitate film formation and maintain a specified viscosity range. Furthermore, by combining auxiliary materials, the physical properties of the film can be adjusted, thereby controlling the mechanical strength, flexibility, and dissolution rate of the water-dissociable film.

[0047] The following will refer to Figures 1 to 6 The present invention provides a detailed description of the hydrolytic thin film and its manufacturing method.

[0048] Figure 1 An exemplary flowchart illustrating a method for manufacturing a cellulose-containing hydrolytic thin film according to an embodiment of the present invention is provided. Figure 2 This is an example diagram used to illustrate pullulan polysaccharide according to an embodiment of the present invention. Figure 3 This is an example diagram used to illustrate carboxymethyl cellulose according to an embodiment of the present invention. Figure 4 This is an example diagram used to illustrate cellulose according to an embodiment of the present invention. Figure 5 Example diagram illustrating the manufacturing process of a cellulose-containing hydrolytic film according to an embodiment of the present invention. Figure 6 This is an example diagram used to illustrate a cellulose-containing hydrolytic thin film according to an embodiment of the present invention. Figures 7 to 9 A diagram illustrating multiple thin films fabricated according to an embodiment of the present invention. Figure 10 An example diagram illustrating the tensile stress-strain curve of a cellulose-containing hydrolytic film according to an embodiment of the present invention. Figure 11 A diagram illustrating a film made by adding a surfactant to a water-dissociable film composition according to an embodiment of the present invention.

[0049] Reference Figure 1 The method for manufacturing a hydrolytically soluble film containing cellulose may include step S100 of preparing a mixed solution containing pullulan, carboxymethyl cellulose (CMC) and cellulose.

[0050] In this invention, the preparation of the mixed solution is a key process for film formation, and it is essential to ensure that the components are uniformly dispersed and form the optimal viscosity range.

[0051] The preparation step of the mixed solution is characterized by dissolving and uniformly mixing the components in appropriate proportions to maintain a viscosity suitable for film formation. This can be achieved by sequentially adding the components to a solvent heated to 50–80°C and stirring at a specified speed to form a homogeneous mixture.

[0052] In one embodiment, a predetermined amount of distilled water is prepared in a reaction vessel and then heated to a temperature of 50–80°C to fully dissolve the mixture. Pullulan is then added and stirred at 1500 rpm to form a homogeneous solution.

[0053] Reference Figure 2 Pullulan, used in the method for manufacturing the hydrolytic thin film of the present invention, is a natural polysaccharide composed of trisaccharide units continuously bonded together with α-(1→6) and α-(1→4) glycosidic bonds. Due to this structural feature, it is considered a substance with excellent water solubility and film-forming properties, as well as excellent compatibility with other biodegradable polymers.

[0054] Pullulan can form colorless and transparent films, and as a natural component, it is environmentally friendly. Furthermore, it possesses excellent oxygen barrier properties, enhancing the film's water retention and freshness preservation. Based on these properties, it can be applied in various fields such as functional packaging materials, food protective films, and medical films.

[0055] Reference Figure 2 The structural formula of pullulan shows that its trisaccharide units are linked by α-(1→4)-glycosidic bonds and α-(1→6)-glycosidic bonds, thereby maximizing its water solubility and film-forming properties. Furthermore, due to this structural feature, it exhibits excellent compatibility with other biodegradable polymers (such as carboxymethyl cellulose and cellulose), thereby allowing for the adjustment of the strength and solubility characteristics of the water-dissociable films of this invention.

[0056] That is, pullulan is a natural polysaccharide with excellent water solubility and film-forming properties, which plays a role in regulating viscosity and forming a uniform structure of the water-dissociable film 100.

[0057] Furthermore, in the embodiments, a specified amount of carboxymethyl cellulose (CMC) is added to a solution in which pullulan is uniformly dissolved, and the mixture is stirred at a speed of 1000-2500 rpm to form a uniform solution.

[0058] In the manufacturing process of the hydrolytically soluble film of this invention, carboxymethyl cellulose is mixed with pullulan and cellulose to regulate the physical properties of the film. The combination of carboxymethyl cellulose and pullulan enhances the film's strength while maintaining a specified viscosity to facilitate film formation. Carboxymethyl cellulose is a hydrophilic polymer that functions to regulate solution viscosity and imparts structural stability during film formation.

[0059] Reference Figure 3 Carboxymethyl cellulose typically exists as a sodium salt (CMC-Na) and is highly compatible with water. Furthermore, when mixed with pullulan, it forms hydrogen bonds and a uniform network structure within the film, thereby enhancing the film's mechanical strength.

[0060] More specifically, the hydrogen bonds in carboxymethyl cellulose can be broadly classified into two types.

[0061] Intrachain hydrogen bonds are bonds formed between hydroxyl groups (-OH) and carboxymethyl groups (-CH2COO) within a single carboxymethyl cellulose molecule. These bonds help maintain the structural stability of the polymer chain and prevent the film from swelling excessively when absorbing moisture.

[0062] Furthermore, intermolecular hydrogen bonds refer to the bonds formed between carboxymethyl cellulose molecules, which enhance the mechanical strength of the film by forming a multipolymer network. In particular, this bonding structure increases the film's durability, and differs from methods that utilize inorganic ions such as phosphorus (P), iron (Fe), magnesium (Mg), and iodine (I) to enhance the mechanical strength of existing polyvinyl alcohol (PVA)-based films.

[0063] According to the embodiments, carboxymethyl cellulose can also form hydrogen bonds with external moisture, thereby maintaining the flexibility of the film while maintaining constant mechanical strength within a specific moisture content.

[0064] According to an embodiment of the present invention, when carboxymethyl cellulose is mixed with pullulan, the polysaccharide structure of pullulan can react with the carboxymethyl group (-CH2COO) of carboxymethyl cellulose. - The interaction between pullulan and carboxymethyl cellulose forms stronger hydrogen bonds. The hydrogen bonds formed between pullulan and carboxymethyl cellulose help maintain a uniform network structure within the film. When carboxymethyl cellulose is used alone, its mechanical strength may be low, but when used with pullulan and cellulose, multiple hydrogen bonds are formed, which can effectively improve the tensile strength of the film.

[0065] Furthermore, unlike the inorganic ion-based reinforcement methods used in existing polyvinyl alcohol-based films, this invention utilizes hydrogen bonds based on natural polysaccharides to ensure better environmental friendliness and superior mechanical properties. Thus, the water-dissociable film of this invention is optimized to maintain strength based on the interaction between carboxymethyl cellulose and pullulan, while dissolving within a specified time after contact with water.

[0066] According to embodiments of the present invention, cellulose can be mixed with pullulan and carboxymethyl cellulose to improve the physical properties of the film and maintain a uniform network structure.

[0067] In one embodiment, the invention is characterized in that pullulan and carboxymethyl cellulose can form an intermolecular hydrogen bond network in a mixed solution, thereby inducing the formation of a uniform structure in the hydrolytic film and improving its mechanical strength.

[0068] According to embodiments, cellulose may include crystalline cellulose, which can enhance the mechanical strength of the film and maintain structural stability.

[0069] As an example, crystalline cellulose refers to a form of cellulose from which amorphous regions have been removed while maintaining high crystallinity. Crystalline cellulose possesses high mechanical strength through strong hydrogen bonds between cellulose chains and can be used as a reinforcing agent for various biodegradable films and environmentally friendly materials.

[0070] In other words, crystalline cellulose has high crystallinity, which can increase the strength and durability of the film. Furthermore, it can form a uniform network through interaction with pullulan and carboxymethyl cellulose, thereby helping to maintain the tensile strength and durability of the film.

[0071] More specifically, cellulose is a natural polymer that provides excellent mechanical strength and serves as a component for maintaining the structural stability of films. Cellulose is inherently a water-soluble polymer, but due to its high crystallinity and strong hydrogen bond network, it is not readily soluble in water on its own. This characteristic is a key factor in enhancing mechanical strength by maximizing the bonding strength between polymer chains within the film. The arrangement of cellulose fibers is maintained by multiple hydrogen bonds formed between the polymer chains, which is why cellulose-based structures exhibit the highest strength.

[0072] Reference Figure 4 Cellulose is a linear polymer composed of repeating glucose (β-D-glucopyranose) units of polysaccharides, exhibiting high structural stability through the formation of a strong hydrogen bond network. In particular, cellulose has excellent hygroscopicity, which allows it to impart a variety of functionalities depending on the composition of the film. When forming a cross-linked structure, it can maintain the film's strength while ensuring flexibility.

[0073] Reference Figure 4 Cellulose is a linear polymer composed of continuous β (1→4) glycosidic bonds and contains a large number of hydroxyl groups (-OH), which allows it to form strong interactions with pullulan and carboxymethyl cellulose.

[0074] In the embodiments, cellulose has the property of being branched and connected in a form similar to paper fiber structure, which plays an important role in maintaining high tensile strength within the film.

[0075] Furthermore, cellulose plays a crucial role in adjusting the mechanical strength of the film when used in conjunction with other filler components. For example, the addition of fillers such as mannitol and xylitol can enhance the mechanical strength of the film, but exceeding a certain filler ratio may cause viscosity issues. Therefore, in embodiments of the present invention, by optimizing the cellulose ratio, additional physical properties can be adjusted while maintaining film strength.

[0076] As described above, the mixed solution of the present invention comprises pullulan, carboxymethyl cellulose (CMC), and cellulose as main components, and can form a uniform network structure through the interaction between these components. More specifically, pullulan is a natural polysaccharide with excellent film-forming properties, which can impart mechanical stability to the film; carboxymethyl cellulose has excellent water solubility, which can provide the function of optimizing the film-forming process by adjusting the solution viscosity. Furthermore, cellulose can form a strong hydrogen bond network, maximizing the mechanical strength of the film, and can regulate the physical properties of the film through its interaction with pullulan and carboxymethyl cellulose.

[0077] According to one embodiment, the mixed solution is characterized by containing no more than 30 parts by weight of carboxymethyl cellulose and no more than 30 parts by weight of cellulose relative to 100 parts by weight of pullulan. That is, in the mixed solution, the content of carboxymethyl cellulose and cellulose relative to 100% by weight of pullulan can be less than 30% by weight. This composition ratio can help optimize the viscosity of the mixed solution during film formation and maintain a uniform network structure within the film.

[0078] According to various embodiments, the mixed solution of the present invention can be composed of main raw materials including pullulan, carboxymethyl cellulose, and cellulose, and auxiliary raw materials for adjusting the mechanical strength, flexibility, and solubility properties of the film. The water-dissociable film of the present invention ensures structural stability through the interaction between the main raw materials, and the physical properties of the film can be more precisely adjusted by adding auxiliary raw materials.

[0079] According to embodiments, the auxiliary materials included in the mixed solution may include at least one of carrageenan, cyclodextrin, sorbitol, and glycerin. Carrageenan is a natural polysaccharide that can improve the viscosity of the film and regulate the dissolution rate. Cyclodextrin can enhance the hydrogen bond network, thereby improving the strength and durability of the film. Furthermore, sorbitol and glycerin can help improve the flexibility of the film, allowing it to maintain appropriate elasticity even after drying.

[0080] According to embodiments of the present invention, the content of auxiliary materials can be approximately 100 parts by weight (preferably less than 100 parts by weight) relative to 100 parts by weight of the main raw material. This can be achieved by combining them in an appropriate proportion in the mixed solution, thereby maintaining a balance between the mechanical strength and solubility characteristics of the film. Furthermore, the content of auxiliary materials can be considered an important factor in adjusting the final physical properties of the film, allowing for the derivation of an optimal ratio to ensure specified water dissociation while maintaining film durability.

[0081] As a specific example, the content of carrageenan can range from 0.1 parts by weight to 2.0 parts by weight relative to the total amount of main and auxiliary raw materials. This can increase the viscosity of the film and regulate the dissolution rate. If the content of carrageenan is too high, it will lead to an excessive increase in film viscosity, which may reduce the uniformity of the coating process. Conversely, if the content is too low, it may reduce the structural stability of the film.

[0082] Furthermore, in one embodiment, cyclodextrin is a cyclic oligosaccharide with a hydrophilic exterior and a hydrophobic interior, which enhances the strength and durability of the film by strengthening the hydrogen bond network within the film of the present invention. As an example, when the content of cyclodextrin relative to the sum of the main raw materials and auxiliary raw materials is in the range of 0.5 parts by weight to 5.0 parts by weight, the physical properties of the film remain balanced; when the content is too high or too low, the tensile strength and flexibility of the film may be affected.

[0083] In particular, cyclodextrins possess the characteristic of forming hydrogen bonds with sodium ions, which plays an important role in enhancing the polymer network within the film. Specifically, hydrogen bonds are formed between the hydroxyl groups (-OH) of carboxymethyl cellulose (CMC) and cellulose and the hydroxyl groups (-OH) of cyclodextrin, while the sodium ions (Na) of carboxymethyl cellulose bind to cyclodextrin, thereby enhancing the network structure.

[0084] During this process, the porous structure of cyclodextrin promotes the formation of hydrogen bonds within the film, and the carboxymethyl (-COO) group of carboxymethyl cellulose... - ) and sodium ions (Na + Carboxymethyl cellulose (-Na) combines with the hydroxyl groups (-OH) of cyclodextrin to form a stable polymer network. This is in contrast to the presence of carboxymethyl cellulose (-Na) alone. + Compared to the previous method, this bonding method can further improve the structural stability of the film and effectively improve its physical strength compared to existing polyvinyl alcohol-based films.

[0085] Furthermore, because cyclodextrins possess a structure capable of forming multiple hydrogen bonds, they can interact with pullulan and carboxymethyl cellulose to form a denser network within the film. When the cyclodextrin content exceeds an appropriate range, excessive hydrogen bonds may form, leading to an overemphasis on the tensile strength of the film, thereby reducing flexibility and causing the film to become brittle. Conversely, when the cyclodextrin content is too low, the network formation within the film may be unstable, resulting in insufficient structural stability.

[0086] In embodiments of the present invention, the content of cyclodextrin is in the range of 0.5 parts by weight to 5.0 parts by weight, thereby optimizing the hydrogen bond network of the film and maintaining a balance between strength and flexibility. In particular, cyclodextrin and carboxymethyl cellulose-Na +The multi-hydrogen bond network formed by cellulose bonding can help maintain the uniform physical properties of the film and modulate its interaction with water.

[0087] Furthermore, in the embodiments, the contents of sorbitol and glycerol can be in the range of 0.5 parts by weight to 10.0 parts by weight, which can help improve the flexibility of the film and maintain appropriate elasticity after drying. When the contents of sorbitol and glycerol are too high, the film surface may become sticky; conversely, when the contents are too low, the film may become over-hardened and brittle.

[0088] In embodiments of the present invention, the mechanical strength, flexibility and hydrolysis properties of the film can be balanced by combining the above-mentioned auxiliary raw materials in a ratio of about 100 parts by weight (preferably less than 100 parts by weight) relative to 100 parts by weight of the main raw materials (pullulan, carboxymethyl cellulose, cellulose).

[0089] In particular, the mixed solution of the present invention not only solves the problem of adjusting the mechanical strength and dissolution rate in existing polyvinyl alcohol (PVA)-based films, but also provides excellent physical properties by using environmentally friendly ingredients.

[0090] In this embodiment, pullulan is used as a component forming the main framework of the film, providing excellent film-forming properties. Carboxymethyl cellulose can adjust the viscosity of the mixed solution, allowing it to be uniformly coated during film formation. Cellulose also provides high mechanical strength, thereby improving the durability of the film.

[0091] Furthermore, the mixed solution of the present invention can be stirred at a specified temperature (e.g., 50–80°C) to form a homogeneous solution. In the process, as hydrogen bonds are formed between pullulan and carboxymethyl cellulose, the network structure within the film can be stably maintained.

[0092] In particular, by adjusting the viscosity of the mixed solution to a range of 1500 centipoise (cps) to below 6500 centipoise, the tensile strength of the film can be optimized, and the uniformity of mechanical strength can be maintained. In a more specific embodiment, the viscosity of the mixed solution is preferably 2200 centipoise to below 3000 centipoise. This corresponds to a range similar to the viscosity of the mixed solution for polyvinyl alcohol-based films (e.g., 2710 cps), effectively maintaining uniform film formation and appropriate mechanical strength. That is, by adjusting the viscosity of the mixed solution to a level similar to that of polyvinyl alcohol-based films (approximately 2200 cps to 3000 cps), the flexibility and processability of the film can be maintained while ensuring mechanical strength.

[0093] According to the embodiments, when the viscosity is too low, the fluidity of the mixed solution increases, resulting in insufficient network formation within the film, which may reduce the structural stability of the film. Conversely, when the viscosity is too high, the mixed solution gels, causing aggregation within the film, making it difficult to form a uniform network, which may lead to uneven tensile strength.

[0094] In embodiments of the present invention, by adjusting the viscosity of the mixed solution to an appropriate range, the hydrogen bonds between pullulan, carboxymethyl cellulose (CMC), and cellulose can be optimized during the film formation process, thereby enabling the tensile strength of the resulting film to be in the range of 20 N to 50 N.

[0095] In a more specific embodiment, in order to ensure similar mechanical strength as polyvinyl alcohol-based films while maintaining solubility and environmental friendliness, the tensile strength is preferably in the range of 35N to 45N.

[0096] This range is appropriate, allowing the water-dissociable film of the present invention to ensure structural stability while maintaining mechanical strength compared to polyvinyl alcohol-based films (e.g., 44.80 N). When the tensile strength is below 35 N, the film's durability may decrease, and when it exceeds 45 N, the film's flexibility may decrease. Therefore, the composition of the present invention ensures an optimal tensile strength range of 35 N to 45 N, thereby providing a film that balances mechanical strength and water dissociability.

[0097] According to various embodiments, the mixed solution of the present invention may be characterized by containing additional raw materials, said additional raw materials including surfactants, and when the additional raw materials are included, the final viscosity is in the range of more than 15,000 centipoise to less than 30,000 centipoise.

[0098] In the embodiments, the additional raw materials, as components used to adjust the physical properties of the film, may include cosmetic raw materials, functional additives, active ingredients, moisturizers, biodegradation promoters, physiologically active ingredients, and other raw materials with industrial application value.

[0099] For example, when surfactants are included as an adjunct ingredient, the film can be used as a cosmetic sheet, such as a facial cleansing sheet. Furthermore, when sodium components such as sodium carbonate are included, it can be formulated into a sheet form with water-soluble properties, thus enabling its use in a variety of applications. The functionality of the film can be adjusted through this composition to meet specific industrial needs. Specifically, in embodiments of the invention, the adjunct ingredients may include one or more of the following: moisturizers (such as hyaluronic acid, glycerin, and propylene glycol), antioxidants (such as vitamin C derivatives and tocopherol), physiologically active ingredients (such as peptides and flavonoids), surfactants (such as lecithin and sodium lauryl sulfate), functional additives (such as zinc oxide and titanium dioxide), and other ingredients with industrial application value.

[0100] In particular, when additional raw materials are included, the mechanical strength and flexibility of the film can be changed by adjusting the final viscosity of the film, and the dissolution rate and release of specific components can be controlled.

[0101] For example, when a humectant is included to adjust the moisture content, the flexibility of the film increases, thereby allowing for adjustment of tensile strength; when a surfactant is included, the dissolution rate of the film can be adjusted.

[0102] Furthermore, when the final viscosity is adjusted to above 15,000 cps, the network formation within the film can be more robust, thereby improving the film's strength and durability. However, when the viscosity exceeds 30,000 cps, the viscoelasticity of the solution increases excessively, thus reducing the processability in the film formation process. Conversely, when the viscosity is below 15,000 cps, the mechanical strength of the film may decrease.

[0103] That is, when the mixed solution of the present invention contains additional raw materials, the mechanical strength, flexibility, and solubility characteristics of the film can be adjusted, and optimal physical properties can be ensured by maintaining the final viscosity between 15,000 cps and 30,000 cps. The functionality of the film may vary depending on the composition and proportion of the additional raw materials, and when specific components are included, the water dissociation rate and release behavior of the film can be adjusted.

[0104] Furthermore, in the embodiments, the method for manufacturing a cellulose-containing hydrolytic film may include step S200 of coating a mixed solution onto a flat plate. The coating process may include steps of forming a film of uniform thickness and optimizing tensile strength and hydrolytic properties.

[0105] Specifically, the mixed solution can be quantitatively coated onto a flat plate (such as a glass plate, silicone mold, metal plate, etc.) to uniformly maintain the film thickness and mechanical strength. The coating process can be performed while maintaining a preset viscosity (1500 cps to 6500 cps, or 15000 cps to 30000 cps when additional raw materials are included).

[0106] According to embodiments, the coating method can employ at least one of casting, roll coating, doctor blade coating, or slot die coating. Casting is primarily suitable for producing uniform films in a laboratory environment, while roll coating or slot die coating can be applied to mass production.

[0107] After the coating process is completed, the mixed solution can be dried at a temperature range of 40–60°C for a specified time to form a thin film. During this process, the hydrogen bond network between pullulan, carboxymethyl cellulose (CMC), cellulose, and other auxiliary materials can be strengthened. Furthermore, the coating thickness may affect the final mechanical properties and water dissociation properties of the film. According to the embodiments, the film thickness can be set in the range of 20 μm to 200 μm, but is not limited to this.

[0108] In embodiments of the present invention, the viscosity of the mixed solution can be adjusted to an optimal range during the coating process, so that the film can maintain a specified tensile strength even after drying.

[0109] Furthermore, in the embodiments, the method for manufacturing a cellulose-containing hydrolytic film may include step S300 of drying a coated mixed solution to form a hydrolytic film.

[0110] According to an embodiment, the water-dissociable film 100 of the present invention has a tensile strength in the range of 20N to 50N, thereby achieving similar mechanical strength as existing polyvinyl alcohol (PVA)-based films in an environmentally friendly manner.

[0111] Polyvinyl alcohol (PVA) films are widely used in existing industries, but their environmental residue has become a problem. The water-dissociable film 100 of this invention aims to solve this problem while achieving tensile strength similar to existing PVA films.

[0112] More specifically, the coated mixture can be dried for a specified time within a temperature range of 40°C to 60°C, during which the hydrogen bond network between pullulan, carboxymethyl cellulose, and cellulose can be strengthened. Furthermore, the drying rate and temperature may directly affect the mechanical properties of the film; in embodiments of the present invention, the drying time can be set within the range of more than 2 hours to less than 24 hours.

[0113] The dried film retains its water-dissociable properties while ensuring tensile strength, thus providing the same or improved physical properties as existing polyvinyl alcohol (PVA) films. In particular, unlike PVA films, the water-dissociable film of this invention ensures mechanical strength through hydrogen bonds between natural polysaccharides without the need for chemical crosslinking agents and is biodegradable after use.

[0114] In summary, such as Figure 5As shown, the method for manufacturing the hydrolytic film of the present invention may include mixing a mixed solution containing pullulan, carboxymethyl cellulose, and cellulose at about 75°C, and then drying it at about 60°C to form a film. A homogeneous solution is formed in the mixing step of the manufacturing process, and the mechanical strength and hydrolytic properties of the film can be adjusted in the coating and drying steps.

[0115] like Figure 6 As shown, the water-dissociative film prepared by the above process can have the following multilayer structure: pullulan forms the main framework of the film, carboxymethyl cellulose constitutes the internal network, and cellulose fibers provide structural support. This structural configuration can increase the tensile strength of the film through hydrogen bonding and play a role in regulating water dissociation under specific temperature and humidity conditions.

[0116] The water-dissociable film of this invention can be composed of raw materials with similar physical properties and environmental friendliness to polyvinyl alcohol-based films, and the mechanical strength, flexibility, and solubility characteristics of the film can be adjusted. This will be further explained in detail through the following experiments.

[0117] Experimental methods and results analysis (Experiment 1)

[0118] To evaluate the mechanical properties of the hydrolytic film of the present invention, tensile strength and viscosity were measured. A polyvinyl alcohol (PVA)-based film was used as a control group to compare and analyze its physical properties with those of pullulan, carboxymethyl cellulose, and cellulose-based hydrolytic films of the present invention.

[0119] 1. Experimental equipment and conditions

[0120] To evaluate the mechanical properties of the water-dissociable film of this invention, tensile strength and viscosity measurements were performed. For tensile strength measurement, an Instron Korea 5569 universal testing machine was used, employing a 1kN load cell and an air pneumatic gripper to fix the specimen. The test rate was set to 3,000 mm / min, and the experiment was conducted using specimens with dimensions of 10 mm wide, 0.210 mm thick, and 30 mm long.

[0121] Viscosity was measured using a CAS CL-R2 viscometer under the following conditions: rotation speed 20 rpm, measurement temperature 25°C. The viscosity characteristics of the mixed solution of this invention were evaluated and compared with polyvinyl alcohol-based films. Furthermore, the viscosity differences between this solution and various compositions composed of pullulan, carboxymethyl cellulose (CMC), cellulose, and other cellulose derivatives (such as hydroxypropyl methyl cellulose) were analyzed. This comparison comprehensively evaluated the impact on film formation, mechanical strength, and water dissociation.

[0122] 2. Preparation of mixed solutions and film formation

[0123] To evaluate the mechanical strength, viscosity, and water dissociation properties of the water-dissociable film of the present invention, a mixed solution of various compositions was prepared, coated onto a plate, and dried to form a film. The physical properties were then measured. For comparative experiments, conventional polyvinyl alcohol-based films (Comparative Example 1), the film of the present invention (Experimental Example 1), and films of various compositions (Experimental Example 2) were manufactured, and their physical properties were compared and analyzed.

[0124] (1) Comparative Example 1: Manufacturing and physical property evaluation of polyvinyl alcohol-based films

[0125] Existing polyvinyl alcohol (PVA)-based films were manufactured and used as standard films for comparison with the films of the present invention. Polyvinyl alcohol (PVA) generally exhibits excellent water solubility and film-forming properties, but as a chemically synthesized polymer, it suffers from poor biodegradability and environmental sustainability. Therefore, based on Comparative Example 1, the possibility of the films of the present invention serving as an environmentally friendly alternative material with similar physical properties to polyvinyl alcohol films was evaluated.

[0126] - Composition: 12% by weight polyvinyl alcohol (PVA), 88% by weight distilled water

[0127] - Manufacturing method: After dissolving polyvinyl alcohol in distilled water, the mixed solution is coated onto a plate and dried to form a film.

[0128] (2) Experimental Example 1: Manufacturing and physical property evaluation of the water-dissociable thin film of the present invention

[0129] The hydrolytic membrane of this invention is composed of pullulan, carboxymethyl cellulose, and cellulose in a specific ratio. In this invention, pullulan serves to form the main framework of the membrane, carboxymethyl cellulose helps to adjust viscosity and increase flexibility, and cellulose enhances the mechanical strength of the membrane.

[0130] -Composition: Composed of 2 to 20 parts by weight of carboxymethyl cellulose and cellulose relative to 100 parts by weight of pullulan. Specifically, relative to 100 parts by weight of the total composition, it consists of 80% by weight of pullulan, 10% by weight of carboxymethyl cellulose and 10% by weight of cellulose.

[0131] - Manufacturing method: Pullulan polysaccharide, carboxymethyl cellulose and cellulose are combined in a specified ratio to prepare a mixed solution, which is then coated on a plate and dried to form a film.

[0132] The hydrolytic thin film of the present invention formed through the above process is as follows: Figure 7 As shown.

[0133] (3) Experimental Example 2: Comparative Experiment of Multiple Compositions

[0134] Thin films in various proportions were prepared for comparison with the optimal composition of the present invention. In Experimental Example 2, various combinations were set up to confirm how the film properties changed with variations in the components and additives.

[0135] In Experiment 2, hydroxypropyl methylcellulose (HMPC) was further used as another cellulose to increase the structural stability of the film and adjust the viscosity of the solution, thereby achieving uniform film formation. Hydroxypropyl methylcellulose is a widely used component in hydrogel sheets, possessing the property of gelling the entire solution and improving stability in cold air processes. Therefore, the aim was to enhance the mechanical strength of the film and ensure its physical properties under specific process conditions.

[0136] ①A composition containing only pullulan and carboxymethyl cellulose (1-1)

[0137] Composition: Contains only pullulan and carboxymethyl cellulose, and contains no cellulose. The composition is made by mixing pullulan and carboxymethyl cellulose in an 8:1 ratio.

[0138] Objective: To determine the effects of viscosity regulation and hydrogen bonding of carboxymethyl cellulose on the strength and hydrolysis properties of pullulan polysaccharide-based films.

[0139] Films made using the composition of this composition, such as Figure 8 As shown.

[0140] ② Compositions containing only pullulan and cellulose (1-2)

[0141] Composition: Contains pullulan and cellulose, but does not contain carboxymethyl cellulose. The composition is made by mixing pullulan and cellulose in an 8:1 ratio.

[0142] Objective: To evaluate the changes in the mechanical strength and physical properties of films when cellulose is added alone.

[0143] ③ Compositions containing pullulan and other cellulose (hydroxypropyl methylcellulose) (1-3)

[0144] Composition: Contains pullulan and hydroxypropyl methylcellulose, used in place of basal cellulose. The composition is prepared by mixing pullulan and hydroxypropyl methylcellulose in an 8:1 ratio.

[0145] Objective: To analyze the effects of hydroxypropyl methylcellulose on water dissociation properties and mechanical strength.

[0146] ④ Compositions containing pullulan, carboxymethyl cellulose, and other celluloses (hydroxypropyl methyl cellulose) (1-4)

[0147] Composition: A composition comprising pullulan, carboxymethyl cellulose, and hydroxypropyl methylcellulose. It consists of pullulan, carboxymethyl cellulose, and hydroxypropyl methylcellulose in an 8:1:1 ratio.

[0148] Objective: To determine the effect of the bonding between carboxymethyl cellulose and hydroxypropyl methyl cellulose on the physical properties of the film.

[0149] ⑤ Compositions containing pullulan, carboxymethyl cellulose, cellulose and other celluloses (hydroxypropyl methyl cellulose) (1-5)

[0150] Composition: A composition comprising pullulan, carboxymethyl cellulose, cellulose, and hydroxypropyl methylcellulose. It consists of pullulan, carboxymethyl cellulose, cellulose, and hydroxypropyl methylcellulose in an 8:1:1:1 ratio.

[0151] Objective: To analyze the changes in mechanical strength and water dissociation properties of thin films when four different component combinations are used.

[0152] ⑥ Compositions containing only carboxymethyl cellulose and cellulose (1-6)

[0153] Composition: A composition consisting only of carboxymethyl cellulose and cellulose, without pullulan. The composition is made by mixing carboxymethyl cellulose and cellulose in a 1:1 ratio.

[0154] Objective: To evaluate whether film formation is possible without pullulan.

[0155] ⑦ Compositions comprising carboxymethyl cellulose, cellulose, and other celluloses (hydroxypropyl methyl cellulose) (1-7)

[0156] Composition: A composition consisting only of carboxymethyl cellulose, cellulose, and hydroxypropyl methylcellulose, without pullulan. The composition is a mixture of carboxymethyl cellulose, cellulose, and hydroxypropyl methylcellulose in a 1:1:1 ratio.

[0157] Objective: To evaluate the formation feasibility and physical properties of pullulan-free cellulose and hydroxypropyl methylcellulose-based films.

[0158] On the other hand, in the experiments of the present invention, in order to compare the dissolution rate of the film, the water dissociation time was measured, and based on this, solubility was defined as slow dissolution (△), moderate dissolution (○), and very fast dissolution (◎).

[0159] ◎ (Extremely fast dissolution): The film dissolves completely within 10 seconds.

[0160] ○ (Moderate dissolution): The film dissolves completely in 10 to 30 seconds.

[0161] △ (Slow dissolution): Requires more than 30 seconds, and some film remains after the specified time.

[0162] - (Dissolution failure or long-term residue): The film has not completely dissolved after more than 120 seconds.

[0163] Actual thin films formed by various combination methods, such as Figure 9 As shown. (Refer to...) Figure 9 Comparative Example 1 (polyvinyl alcohol-based film) has a transparent and uniform surface, and Experimental Example 1 (the preferred composition of the present invention) also exhibits a relatively uniform film shape. On the other hand, in Experimental Example 2, it was confirmed that the shape and surface properties of the film change with the composition, especially in the composition containing hydroxypropyl methylcellulose, the film surface tends to have a porous structure. This result reflects the gelling properties of hydroxypropyl methylcellulose, indicating that it can increase the structural stability of the film in certain compositions.

[0164] 3. Results Analysis

[0165] To evaluate the mechanical strength, viscosity, and water dissociation properties of the water-dissociable film of the present invention, physical properties were measured for Comparative Example 1 (polyvinyl alcohol-based film), Experimental Example 1 (the optimal composition of the present invention), and Experimental Example 2 (various compositions), and the results are as follows.

[0166] Table 1

[0167]

[0168] (1) Viscosity analysis

[0169] Viscosity measurements confirmed that Comparative Example 1 (polyvinyl alcohol-based film) had a viscosity of 2710 cps, while Experimental Example 1 (the preferred composition of the present invention) had a viscosity of 2350 cps. The viscosity of the mixed solution of the present invention is slightly lower than that of the polyvinyl alcohol-based solution, but it maintains the viscosity level required for film formation.

[0170] In Experiment 2, the viscosity varied considerably with changes in the composition. The compositions containing pullulan and carboxymethyl cellulose (1-1) and those containing only pullulan and cellulose (1-2) had relatively low viscosities of 2030 cps and 1350 cps, respectively. This indicates that the viscosity-adjusting effect is limited when carboxymethyl cellulose and cellulose are added alone. Conversely, the compositions containing pullulan and other cellulose (hydroxypropyl methylcellulose) (1-3) and pullulan, carboxymethyl cellulose, and hydroxypropyl methylcellulose (1-4) had viscosities of 1710 cps and 6100 cps, respectively, indicating a significant viscosity change after the addition of hydroxypropyl methylcellulose. In particular, the composition containing pullulan, carboxymethyl cellulose, cellulose, and hydroxypropyl methylcellulose (1-5) had a viscosity as high as 6130 cps, suggesting that excessively high viscosity may lead to difficulties in uniform film coating.

[0171] The viscosities of compositions containing only carboxymethyl cellulose and cellulose (1-6) and compositions containing only carboxymethyl cellulose, cellulose and hydroxypropyl methyl cellulose (1-7) were 428 cps and 514 cps, respectively, indicating that pullulan plays an important role in the film-forming process.

[0172] (2) Tensile strength analysis

[0173] Tensile strength measurements confirmed that Comparative Example 1 (polyvinyl alcohol-based film) had a tensile strength of 44.80 N, while Experimental Example 1 (the preferred composition of the present invention) had a tensile strength of 43.30 N. This means that the mechanical strength of the film of the present invention can reach a level similar to that of polyvinyl alcohol-based film, indicating its potential to replace existing polyvinyl alcohol-based films.

[0174] In Experiment 2, the tensile strength values ​​varied considerably with changes in the composition. The composition (1-1) containing only pullulan and carboxymethyl cellulose had a tensile strength of 14.31 N, while the composition (1-2) containing only pullulan and cellulose had a tensile strength of 19.64 N, exhibiting relatively low mechanical strength. This indicates that the mechanical strength enhancement effect is limited when cellulose and carboxymethyl cellulose are added alone.

[0175] Conversely, the tensile strength of compositions (1-3) containing pullulan and other cellulose (hydroxypropyl methylcellulose) was 22.67 N, while the tensile strength of compositions (1-4) containing pullulan, carboxymethyl cellulose, and hydroxypropyl methylcellulose was 29.29 N, indicating a trend towards increased mechanical strength when hydroxypropyl methylcellulose is included. In particular, compositions (1-5) containing pullulan, carboxymethyl cellulose, cellulose, and hydroxypropyl methylcellulose exhibited the highest tensile strength of 34.33 N, but may have issues with increased viscosity and coating uniformity.

[0176] Compositions containing only carboxymethyl cellulose and cellulose (1-6) and compositions containing only carboxymethyl cellulose, cellulose, and hydroxypropyl methyl cellulose (1-7) could not be measured for tensile strength, indicating that pullulan plays a crucial role in film formation and ensuring mechanical strength.

[0177] (3) Water dissociation assessment

[0178] The results of the water dissociation evaluation confirmed that Comparative Example 1 (polyvinyl alcohol film) completely dissolved within 10 seconds (◎), and Experimental Example 1 (the preferred composition of the present invention) also completely dissolved within 10 seconds (◎), showing a similar dissolution rate to the polyvinyl alcohol film.

[0179] In Experiment 2, the hydrolysis properties varied with the composition. The composition containing only pullulan and carboxymethyl cellulose (1-1) and the composition containing only pullulan and cellulose (1-2) completely dissolved in 10 seconds to less than 30 seconds (○), showing a faster dissolution rate.

[0180] Conversely, compositions containing pullulan and other cellulose (hydroxypropyl methylcellulose) (1-3), compositions containing pullulan, carboxymethyl cellulose, and hydroxypropyl methylcellulose (1-4), and compositions containing pullulan, carboxymethyl cellulose, cellulose, and hydroxypropyl methylcellulose (1-5) require dissolution times of more than 30 seconds and exhibit a tendency to leave a specified amount of film (Δ). This is interpreted as the dissolution rate decreasing as the structural strength of the film increases when hydroxypropyl methylcellulose is included.

[0181] Compositions containing only carboxymethyl cellulose and cellulose (1-6) and compositions containing only carboxymethyl cellulose, cellulose, and hydroxypropyl methyl cellulose (1-7) failed to form films, and therefore could not be evaluated for dissolution rate.

[0182] (4) Derivation of the optimal composition

[0183] The comprehensive analysis of the results of this experiment confirmed that Experiment 1 (a composition containing pullulan, carboxymethyl cellulose and cellulose) achieved the best balance in terms of viscosity (2350 cps), tensile strength (43.30 N), and water dissociation (◎).

[0184] It has been confirmed that this composition maintains a similar level of mechanical strength to polyvinyl alcohol-based films while being more environmentally friendly than existing polyvinyl alcohol films, and its dissolution rate is also at the same level as existing polyvinyl alcohol films.

[0185] Further reference Figure 10 The figure shows the tensile stress-strain curves of the films manufactured from the preferred composition of the present invention. Analysis of the graphs reveals that the water-dissociative films of the present invention experience a rapid increase in stress during the initial elastic phase, with a maximum tensile strength of approximately 20 MPa. The stress then remains at a specified level, and fracture occurs at a strain rate of approximately 70%.

[0186] On the other hand, the tensile strength value in MPa is converted to suit the experimental conditions as follows. The cross-sectional area (width x thickness) of the specimen used in this experiment is 10 mm × 0.21 mm = 2.1 mm² = 2.1 × 10⁻⁶. -6 m². Therefore, 20MPa (=20N / mm²)×2.1mm²=42N, which means that the film of the present invention can withstand a maximum tensile load of approximately 42N.

[0187] This property exhibits a level of mechanical properties similar to those of polyvinyl alcohol-based films, indicating that the dissolution rate can be optimized while ensuring the film's durability and tensile strength. In particular, the stress retention region formed after the elastic segment is relatively wide, which suggests that the composition of the present invention effectively maintains the film's durability. This can be explained by the increased stability of the film structure due to the interaction between pullulan, carboxymethyl cellulose, and cellulose.

[0188] As described above, it can be confirmed that the hydrolytic film of the present invention, employing a pullulan-carboxymethyl cellulose-cellulose combination, achieves the same level of mechanical strength as existing polyvinyl alcohol-based films while being made from environmentally friendly materials. In particular, by using pullulan as the main framework of the film, utilizing carboxymethyl cellulose to adjust viscosity and induce the formation of a uniform film, and adding cellulose as a reinforcing material, mechanical strength can be maintained.

[0189] Furthermore, the film of this invention exhibits a water dissociation rate similar to that of polyvinyl alcohol-based films and demonstrates rapid dissolution upon contact with water. This suggests its potential to replace existing polyvinyl alcohol-based products in the fields of environmentally friendly water-dissociable packaging and disposable films.

[0190] Furthermore, the thin film manufacturing process of the present invention has the advantages of not requiring high-temperature processes and being easy to combine with a variety of auxiliary raw materials (humectants, functional additives, etc.).

[0191] For example, when the compositions of the embodiments of the present invention (pullulan, carboxymethyl cellulose, and cellulose) further contain surfactants, they can be used as cosmetic sheets, such as facial cleansing sheets. Films made from such compositions can have shapes such as... Figure 11 As shown, it has a soft texture and appropriate water dissociation properties, making it suitable for cleaning and cosmetic applications.

[0192] Therefore, it can be applied to various industrial fields such as food packaging materials, medical films, cosmetic sheets and functional solvent films. Compared with existing synthetic polymer films, it has the value of being an environmentally friendly alternative material with excellent biodegradability and improved chemical stability.

[0193] Ultimately, the pullulan-carboxymethyl cellulose-cellulose-based hydrolytic film of the present invention overcomes the limitations of existing polyvinyl alcohol-based films and provides an optimal composition that simultaneously satisfies environmental friendliness, mechanical stability and rapid dissolution rate, thereby offering a highly applicable solution for a variety of industrial fields.

[0194] Experimental methods and results analysis (Second Experiment)

[0195] To evaluate the mechanical properties of the pullulan-carboxymethyl cellulose-cellulose-based hydrolytic thin film of the present invention under different relative proportions of the main components, tensile strength and viscosity measurements were performed. The experiments were conducted when the contents of carboxymethyl cellulose and cellulose were 1% to 25% by weight of each pullulan. The experimental conditions and methods were the same as in the first experiment, and the results are as follows.

[0196] Table 2

[0197]

[0198] It was confirmed that when the content of cellulose and carboxymethyl cellulose reached 20%, the water dissociation property decreased slightly, and when it reached 22%, the water dissociation property decreased significantly. This was analyzed as follows: with the increase of cellulose content, the strength increased significantly, and with the increase of carboxymethyl cellulose content, the gelation also increased significantly. Furthermore, in Experiment 1, where the content of both cellulose and carboxymethyl cellulose was 1%, it was confirmed that its tensile strength was significantly lower than that of Experiment 2. When the tensile strength was below 25 N, the film had difficulty maintaining its shape.

[0199] Ultimately, it can be seen that when the mixing amount of carboxymethyl cellulose and cellulose relative to each pullulan is 2% to 20%, it has suitable tensile strength for hydrolysis and film formation.

[0200] Although embodiments of the invention have been described above with reference to the accompanying drawings, those skilled in the art will understand that the invention can be implemented in other specific forms without altering its technical spirit or essential characteristics. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

[0201] The specific embodiments described in this invention are merely one example and do not limit the scope of the invention in any way. For brevity, descriptions of conventional electronic structures, control systems, software, and other functional aspects of said systems may be omitted. Furthermore, the line connections or connecting parts between structural elements shown in the drawings are only illustrative representations of functional connections and / or physical or circuit connections, and may represent various alternative or additional functional, physical, or circuit connections in actual devices. Additionally, unless specifically stated as "necessary" or "important," such structural elements may not be absolutely essential for the application of this invention.

[0202] It should be understood that the specific order or hierarchy of steps in the proposed process is merely one example of an exemplary method. It should be understood that, based on design priorities, the specific order or hierarchy of steps in the process can be rearranged within the scope of this invention. The appended method invention claims to provide the elements of each step in the order of the example, but is not intended to limit itself to the specific order or hierarchy of steps presented in this specification.

[0203] The description of the proposed embodiments is intended to enable those skilled in the art to use or implement the invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the scope of the invention. Therefore, the invention is not intended to be limited to the embodiments presented herein, but should be interpreted within the broadest scope consistent with the principles and novel features set forth herein.

[0204] Embodiments of the present invention

[0205] The relevant content has been described in the above specific implementation methods.

Claims

1. A hydrolyzable film comprising cellulose, characterized in that, The hydrolytic membrane contains pullulan, carboxymethyl cellulose, and cellulose.

2. The cellulose-containing hydrolytic film according to claim 1, characterized in that, In the water-dissociable membrane, The content of carboxymethyl cellulose relative to 100 parts by weight of the pullulan is in the range of more than 2 parts by weight and less than 20 parts by weight. The cellulose content is in the range of more than 2 parts by weight and less than 20 parts by weight relative to 100 parts by weight of pullulan.

3. The cellulose-containing hydrolytic film according to claim 1, characterized in that, The hydrolytic film is formed from a mixed solution with a viscosity ranging from 1500 centipoise to 6500 centipoise.

4. The cellulose-containing hydrolytic film according to claim 1, characterized in that, The tensile strength of the hydrolytic film is in the range of 20N to 50N.

5. The cellulose-containing hydrolytic film according to claim 1, characterized in that, The hydrolytic thin film forms an intermolecular hydrogen bond network between the pullulan and the carboxymethyl cellulose.

6. The cellulose-containing hydrolytic film according to claim 1, characterized in that, The water-dissociable membrane comprises: The main raw materials include pullulan, carboxymethyl cellulose, and cellulose; and Auxiliary raw materials are used to adjust the mechanical strength, flexibility, and solubility properties of the film. The content of the auxiliary raw materials is less than 100 parts by weight relative to 100 parts by weight of the main raw material.

7. The cellulose-containing hydrolytic film according to claim 6, characterized in that, The auxiliary ingredients include at least one of carrageenan, cyclodextrin, sorbitol and glycerol.

8. The cellulose-containing hydrolytic film according to claim 1, characterized in that, The water-dissociable film may contain additional raw materials, including surfactants, in which case the final viscosity is in the range of more than 15,000 centipoise to less than 30,000 centipoise.

9. A method for manufacturing a hydrolyzable film containing cellulose, characterized in that, include: The steps for preparing a mixed solution containing pullulan, carboxymethyl cellulose, and cellulose; The step of coating the mixed solution onto a plate; as well as The step of drying the coated mixed solution to form a hydrolytic film.

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