Water-soluble film comprising cellulose and manufacturing method therefor

Abstract

Disclosed is a water-soluble film comprising cellulose according to various embodiments of the present invention to achieve the above-described objective. The water-soluble film comprises pullulan, carboxymethyl cellulose, and cellulose.

Description

Water-decomposable film containing cellulose and method for producing the same

[0001] The present invention relates to a water-soluble film, and more specifically, to an environmentally friendly water-soluble film comprising cellulose that can replace existing water-soluble films comprising polyvinyl alcohol (PVA), and a method for producing the same.

[0002]

[0003] Demand for water-soluble films has been increasing across various industries. Water-soluble films rapidly dissolve upon contact with water under certain conditions and do not remain in the environment. Therefore, they are widely used in various fields, including detergent packaging, pharmaceutical capsules, food packaging, and industrial coatings. In particular, as conventional plastic films have been identified as a major source of environmental pollution, research into biodegradable or water-soluble film materials is actively underway.

[0004] The most widely used water-soluble film material today is polyvinyl alcohol (PVA). PVA possesses excellent water solubility, mechanical strength, and relatively rapid decomposition after dissolution, leading to its widespread application across industries. For example, a wide range of products are manufactured using PVA-based films, including laundry capsule films, pesticide packaging, medical water-soluble bags, and food packaging.

[0005] However, recent research has shown that PVA, while water-soluble, has limitations in terms of biodegradability. Specifically, it is possible that it may not completely decompose during wastewater treatment and instead remain in the form of fine polymers, accumulating in the environment. Reports from the U.S. Environmental Protection Agency (EPA) and several research institutes indicate that approximately 75% of PVA-based films do not fully decompose after wastewater treatment and are 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.

[0006] Accordingly, the development of alternative materials that simultaneously satisfy both water dissociation and mechanical strength without the use of PVA is essential. However, existing research on alternative materials has several limitations. For example, films based on natural polymers (e.g., cellulose, starch, chitosan, etc.) exhibit excellent water solubility but have lower mechanical strength than PVA, making them brittle and prone to breakage. Conversely, some synthetic polymers exhibit excellent mechanical strength but have poor water dissociation, resulting in prolonged dissolution times or residues.

[0007] In particular, manufacturing water-dissociable films without PVA is technically challenging. PVA plays a role in optimizing the viscosity of the solution during the film formation process and helping to form a uniform thin film. In other words, manufacturing a film without PVA requires addressing three key factors: viscosity control, securing the film's mechanical strength, and controlling water dissociation. In general, if the viscosity of a natural polymer-based film is too low, it becomes water-like, making film formation impossible. If the viscosity is too high, gelation occurs, making it difficult to manufacture a uniform thin film. Furthermore, if the bonding between water-soluble polymers is weak, the film can easily tear or its mechanical strength can deteriorate rapidly.

[0008] Therefore, there is an urgent need to develop alternative technologies that can maintain physical properties similar to those of existing PVA-based films without incorporating PVA. In particular, with recently strengthened environmental regulations, there is a need for new, eco-friendly film materials that are fully biodegradable and do not generate microplastic emissions. To achieve this, precise design in the film composition and manufacturing process is essential.

[0009] (Prior art literature)

[0010] (Patent Document)

[0011] (Patent Document 1) Republic of Korea Patent Publication No. 10-2023-0020601 (February 13, 2023)

[0012]

[0013] The problem to be solved by the present invention is to overcome the environmental limitations of polyvinyl alcohol (PVA)-based water-dissociable films and to provide an alternative film that can maintain excellent water-dissociability and mechanical strength without PVA.

[0014] The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0015]

[0016] A water-dissociable film comprising cellulose according to various embodiments of the present invention for solving the above-described problems is disclosed. The water-dissociable film may be characterized by comprising plurane, carboxymethyl cellulose, and cellulose.

[0017] In an alternative embodiment, the hydrophilic film may be characterized in that the carboxymethyl cellulose is included in an amount of 2 parts by weight or more and 20 parts by weight or less relative to 100 parts by weight of the pullulan, and the cellulose is included in an amount of 2 parts by weight or more and 20 parts by weight or less relative to 100 parts by weight of the pullulan.

[0018] In an alternative embodiment, the hydrophilic film may be characterized by being formed using a mixed solution having a viscosity in a range of 1,500 centipoise (cps) or more and 6,500 centipoise or less.

[0019] In an alternative embodiment, the hydrophilic film may be characterized by having a tensile strength in a range of 20 N or more and 50 N or less.

[0020] In an alternative embodiment, the hydrophilic film may be characterized by forming an intermolecular hydrogen bonding network between the pulverulent and the carboxymethylcellulose.

[0021] In an alternative embodiment, the hydrophilic film may include a main raw material including the pullulan, the carboxymethyl cellulose, and the cellulose, and a secondary raw material for controlling the mechanical strength, flexibility, and solubility properties of the film, and may be characterized in that the secondary raw material is included in an amount of 100 parts by weight or less based on 100 parts by weight of the main raw material.

[0022] In an alternative embodiment, the excipient may include at least one of Carrageenan, Cyclodextrin, Sorbitol, and Glycerin.

[0023] In an alternative embodiment, the hydrophilic film may comprise additional ingredients including a surfactant, in which case the final viscosity may be characterized as being in the range of 15,000 centipoise or more and 30,000 centipoise or less.

[0024] In another embodiment of the present invention, a method for producing a water-dissociable film comprising cellulose is disclosed. The method may include the steps of preparing a mixed solution comprising plurane, carboxymethylcellulose, and cellulose, applying the mixed solution to a flat plate, and drying the applied mixed solution to form a water-dissociable film.

[0025]

[0026] According to various embodiments of the present invention, a water-dissolvable film can be provided that can achieve viscosity and tensile strength similar to existing polyvinyl alcohol (PVA)-based films without the need for PVA. This effectively addresses the environmental issues associated with existing PVA-based films while maintaining the film's mechanical strength and processability.

[0027] Furthermore, the film of the present invention is fully biodegradable and exhibits environmentally friendly properties, not causing environmental pollution such as microplastics during wastewater treatment. Therefore, it can comply with strengthening global environmental regulations and can be utilized as a sustainable alternative material in various industrial fields.

[0028] Additionally, the physical properties of the film can be further improved by combining auxiliary materials as needed. For example, the addition of specific softeners and cross-linking agents can improve the elasticity and durability of the film, while the addition of viscosity modifiers can enhance processability during film formation. This configuration adjustment has the advantage of allowing the physical properties of the film to be optimized for the intended purpose.

[0029] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

[0030]

[0031] Various aspects are now described with reference to the drawings, wherein like reference numerals are used to refer to similar components generally. In the following examples, for purposes of explanation, numerous specific details are set forth to provide a comprehensive understanding of one or more aspects. However, it will be apparent that such aspects may be practiced without these specific details.

[0032] Figure 1 shows an exemplary flow chart of a method for manufacturing a water-soluble film comprising cellulose according to one embodiment of the present invention.

[0033] Figure 2 is an exemplary diagram illustrating a flurane related to one embodiment of the present invention.

[0034] Figure 3 is an exemplary diagram illustrating carboxymethyl cellulose related to one embodiment of the present invention.

[0035] Figure 4 is an exemplary diagram illustrating cellulose related to one embodiment of the present invention.

[0036] FIG. 5 is an exemplary diagram illustrating a process for manufacturing a water-soluble film including cellulose according to one embodiment of the present invention.

[0037] FIG. 6 is an exemplary diagram illustrating a water-dissociable film including cellulose related to one embodiment of the present invention.

[0038] Figures 7 to 9 are drawings showing films produced as a result of experiments related to one embodiment of the present invention.

[0039] FIG. 10 is an exemplary diagram showing a tensile stress-strain curve of a water-soluble film containing cellulose according to one embodiment of the present invention.

[0040] FIG. 11 is a drawing showing a film produced by adding a surfactant to a water-soluble film composition according to one embodiment of the present invention.

[0041]

[0042] Various embodiments and / or aspects are now disclosed with reference to the drawings. In the following description, for purposes of explanation, numerous specific details are set forth to provide a thorough understanding of one or more aspects. However, it will be apparent to one skilled in the art that the aspect(s) may be practiced without these specific details. The following description and the accompanying drawings detail specific exemplary aspects of one or more aspects. However, these aspects are exemplary, and any of the various methods within the principles of the various aspects may be utilized, and the description is intended to encompass all such aspects and their equivalents. Specifically, the terms "embodiment," "example," "aspect," and "example" as used herein are not intended to imply that any aspect or design described therein is preferred or advantageous over other aspects or designs.

[0043] Hereinafter, regardless of the drawing numbers, identical or similar components are assigned the same reference numerals, and redundant descriptions thereof are omitted. Furthermore, when describing the embodiments disclosed in this specification, if a detailed description of a related known technology is judged to obscure the gist of the embodiments disclosed in this specification, the detailed description thereof will be omitted. Furthermore, the attached drawings are only intended to facilitate easy understanding of the embodiments disclosed in this specification, and the technical concepts disclosed in this specification are not limited by the attached drawings.

[0044] The purposes and effects of the present invention, as well as the technical configurations for achieving them, will become clearer with reference to the embodiments described in detail below, along with the accompanying drawings. In describing the present invention, detailed descriptions of known functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the invention. Furthermore, the terms described below are defined based on their functions in the present invention and may vary depending on the intentions or practices of the user or operator.

[0045] However, the present invention is not limited to the embodiments disclosed below and can be implemented in various other forms. These embodiments are provided solely to ensure the completeness of the present invention and to fully inform those skilled in the art of the scope of the disclosure. The present invention is defined solely by the scope of the claims. Therefore, such definitions should be based on the contents of this specification.

[0046]

[0047] Water-soluble films are widely used in a variety of industries, attracting particular attention in areas such as detergent packaging, food packaging, pharmaceutical capsules, and industrial coatings. Polyvinyl alcohol (PVA) is the primary raw material used in existing water-soluble films. PVA boasts excellent film-forming ability and mechanical strength, enabling a stable manufacturing process and superior performance.

[0048] However, despite its water-soluble properties, PVA is reported to be difficult to fully biodegrade in the environment. In particular, the possibility that some of the undecomposed PVA could be released into the environment during wastewater treatment has raised the need for eco-friendly alternatives to PVA. Accordingly, films based on natural polymers are being considered as an alternative. However, existing natural polymer films suffer from low mechanical strength and poor processability, hindering their practical application.

[0049] The present invention provides a water-dissolvable film that can maintain viscosity and tensile strength similar to existing PVA-based films without including PVA, and for this purpose, a film manufacturing method based on a specific composition is proposed.

[0050] The water-dissociable film of the present invention is an environmentally friendly film that is configured to achieve mechanical strength and viscosity similar to existing PVA-based films without containing polyvinyl alcohol (PVA). The water-dissociable film of the present invention is based on a composition comprising cellulose, and the composition ratio and manufacturing process have been optimized to facilitate film formation while maintaining a certain viscosity range. Furthermore, the physical properties of the film can be adjusted through the combination of auxiliary materials, thereby controlling the mechanical strength, flexibility, and dissolution rate of the water-dissociable film.

[0051] A detailed description of the hydrophilic film of the present invention and its manufacturing method will be described below with reference to FIGS. 1 to 6.

[0052] FIG. 1 is an exemplary flowchart illustrating a method for manufacturing a water-dissociable film comprising cellulose according to an embodiment of the present invention. FIG. 2 is an exemplary diagram illustrating a pulan according to an embodiment of the present invention. FIG. 3 is an exemplary diagram illustrating carboxymethyl cellulose according to an embodiment of the present invention. FIG. 4 is an exemplary diagram illustrating cellulose according to an embodiment of the present invention. FIG. 5 is an exemplary diagram illustrating a process for manufacturing a water-dissociable film comprising cellulose according to an embodiment of the present invention. FIG. 6 is an exemplary diagram illustrating a water-dissociable film comprising cellulose according to an embodiment of the present invention. FIGS. 7 to 9 are diagrams illustrating films produced as experimental results according to an embodiment of the present invention. FIG. 10 is an exemplary diagram illustrating a tensile stress-strain curve of a water-dissociable film comprising cellulose according to an embodiment of the present invention. FIG. 11 is a drawing showing a film produced by adding a surfactant to a water-soluble film composition according to one embodiment of the present invention.

[0053]

[0054] Referring to FIG. 1, a method for manufacturing a water-dissolvable film including cellulose may include a step (S100) of manufacturing a mixed solution including pullulan, carboxymethyl cellulose (CMC), and cellulose.

[0055] In the present invention, the preparation of a mixed solution is a key process for film formation, and it is important to ensure that each component is homogeneously dispersed and an optimal viscosity range is formed.

[0056] The step of preparing a mixed solution is characterized by dissolving each component in an appropriate ratio and mixing it homogeneously to maintain a viscosity suitable for film formation. This may involve sequentially adding each component to a solvent heated to 50-80°C and stirring at a constant speed to form a uniform composition.

[0057] In one embodiment, a certain amount of distilled water is prepared in a reaction vessel and heated to a temperature of 50 to 80°C to facilitate the smooth dissolution of the mixed components. Then, after adding plurane, the mixture is stirred at a speed of 1,500 rpm to form a homogeneous solution.

[0058] Referring to FIG. 2, the pullulan used in the method for producing a hydrolyzable film of the present invention is a natural polysaccharide composed of a continuous bond of triglucoside units having α-(1→6) and α-(1→4) glycosidic bonds. Due to these structural characteristics, it is evaluated as a material with excellent water solubility and film-forming ability, and excellent compatibility with other biodegradable polymers.

[0059] Plurane can form colorless, transparent films, and its natural composition makes it environmentally friendly. Furthermore, its high oxygen barrier properties enhance moisture retention and preservation within the film. These properties make it ideal for a variety of applications, including functional packaging materials, food protective films, and medical films.

[0060] Referring to the structural formula of Fig. 2, pullulan has a structure in which triglucoside units are linked via α-(1→4)-glycosidic bonds and α-(1→6)-glycosidic bonds, which plays a role in maximizing water solubility and film-forming ability. In addition, due to these structural features, it has excellent compatibility with other biodegradable polymers (e.g., carboxymethyl cellulose, cellulose), and through this, the strength and dissolution characteristics of the water-dissociable film of the present invention can be controlled.

[0061] That is, fullan is a natural polysaccharide with excellent water solubility and film-forming ability, and plays a role in controlling viscosity and forming a homogeneous structure of a water-dissociable film (100).

[0062] Additionally, in the embodiment, a certain amount of carboxymethylcellulose (CMC) may be additionally added to a solution in which pulani is homogeneously dissolved, and stirred at a speed of 1,000 to 2,500 rpm to form a homogeneous solution.

[0063] During the process of manufacturing the water-dissociable film of the present invention, CMC, when mixed with pullulan and cellulose, plays a role in controlling the physical properties of the film. CMC, when combined with pullulan, reinforces the film's strength while maintaining a constant viscosity, facilitating film formation. As a hydrophilic polymer, CMC regulates the viscosity of the solution and provides structural stability during film formation.

[0064] Referring to Figure 3, it generally exists in the form of a sodium salt (CMC-Na) and has high compatibility with water. Furthermore, when mixed with fuluran, it forms hydrogen bonds, creating a homogeneous network structure within the film, thereby enhancing the mechanical strength of the film.

[0065] More specifically, hydrogen bonding within CMC can be broadly divided into two types.

[0066] Intrachain hydrogen bonds are bonds formed between hydroxyl groups (-OH) and carboxymethyl groups (-CH₂COO) within a single CMC molecule. These bonds contribute to maintaining the structural stability of the polymer chain and prevent excessive swelling of the film when water is absorbed.

[0067] Furthermore, intermolecular hydrogen bonds, which are formed between CMC molecules, play a role in enhancing the mechanical strength of the film by forming a multi-polymer network. In particular, this bonding structure increases the durability of the film and has characteristics that differentiate it from reinforcing methods utilizing inorganic ions such as phosphorus (P), iron (Fe), magnesium (Mg), and iodine (I), which were used to reinforce the mechanical strength of conventional polyvinyl alcohol (PVA)-based films.

[0068] According to an embodiment, CMC can form hydrogen bonds with external moisture, thereby maintaining the flexibility of the film while maintaining constant mechanical strength within a certain moisture content.

[0069] According to an embodiment of the present invention, when CMC and pullulan are mixed, the polysaccharide structure of pullulan and the carboxymethyl group (-CH₂COO) of CMC - ) can interact to form stronger hydrogen bonds. The hydrogen bonds formed between pullulan and CMC can contribute to maintaining a homogeneous network structure within the film. CMC may have low mechanical strength when used alone, but when used together with pullulan and cellulose, it can form multiple hydrogen bonds, effectively improving the tensile strength of the film.

[0070] Furthermore, unlike the inorganic ion-based reinforcement used in conventional PVA-based films, the present invention utilizes hydrogen bonding based on natural polysaccharides to achieve superior mechanical properties while being more environmentally friendly. Accordingly, the water-releasable film of the present invention is optimized to maintain strength through the interaction between CMC and fulran, while also dissolving within a certain time upon contact with water.

[0071] According to an embodiment of the present invention, cellulose can be mixed with pulverin and CMC to improve the physical properties of the film and maintain a homogeneous network structure.

[0072] In one embodiment, the plurane and carboxymethyl cellulose may be characterized by forming an intermolecular hydrogen bonding network in a mixed solution, thereby inducing uniform structural formation of a water-dissociable film and improvement in mechanical strength.

[0073] According to an embodiment, the cellulose may include crystalline cellulose, which can reinforce the mechanical strength of the film and maintain structural stability.

[0074] For example, crystalline cellulose can be a form of natural cellulose that maintains high crystallinity by removing amorphous regions. Crystalline cellulose possesses high mechanical strength through strong hydrogen bonds between cellulose chains and can be utilized as a reinforcing agent in various biodegradable films and eco-friendly materials.

[0075] That is, crystalline cellulose possesses high crystallinity and can play a role in increasing strength and durability within the film. Furthermore, through interaction with plurane and CMC, it forms a uniform network, contributing to maintaining the tensile strength and durability of the film.

[0076] More specifically, cellulose, as a natural polymer, provides excellent mechanical strength and serves as a component that maintains the structural stability of the film. While cellulose is inherently a water-soluble polymer, its high crystallinity and strong hydrogen bonding network prevent it from dissolving easily in water on its own. These characteristics are crucial for maximizing the bonding between polymer chains within the film, thereby enhancing its mechanical strength. The alignment of cellulose fibers is maintained by multiple hydrogen bonds formed between the polymer chains, which contributes to the film's highest strength among cellulose-based structures.

[0077] Referring to Figure 4, cellulose is a linear polymer composed of repeating glucose (β-D-glucopyranose) units of polysaccharides, forming a strong hydrogen bond network and exhibiting high structural stability. In particular, cellulose has excellent water absorption, allowing it to impart various functionalities depending on the film's composition. Furthermore, when cross-linked, it can maintain film strength while ensuring flexibility.

[0078] Referring to the molecular structure of Figure 4, cellulose is a linear polymer composed of continuous β(1→4) glycosidic bonds, and contains a large amount of hydroxyl groups (-OH), which can form strong interactions with pullulan and CMC.

[0079] In an embodiment, the cellulose has the property of branching and linking in a manner similar to the paper fiber structure, and this structural feature may play an important role in maintaining high tensile strength within the film.

[0080] Additionally, cellulose can play a significant role in controlling the mechanical strength of the sheet when applied in combination with other filler components. For example, fillers such as mannitol and xylitol can supplement the mechanical strength of the film, but if a certain ratio is exceeded, increased stickiness may occur. Accordingly, embodiments of the present invention can be provided to optimize the ratio of cellulose to maintain the strength of the film while adjusting additional physical properties.

[0081] As described above, the mixed solution of the present invention comprises pullulan, carboxymethylcellulose (CMC), and cellulose as main components, and can be configured to form a homogeneous network structure through interactions among the components. More specifically, pullulan is a natural polysaccharide with excellent film-forming ability, and it plays a role in providing mechanical stability to the film. CMC has excellent water solubility and can provide the function of optimizing the film formation process by controlling the viscosity of the solution. In addition, cellulose forms a strong hydrogen bonding network to maximize the mechanical strength of the film, and it plays a role in controlling the physical properties of the film through interactions with pullulan and CMC.

[0082] According to one embodiment, the mixed solution may be characterized in that it contains carboxymethylcellulose in an amount of 30 parts by weight or less relative to 100 parts by weight of pullulan, and cellulose in an amount of 30 parts by weight or less relative to 100 parts by weight of pullulan. That is, in the mixed solution, CMC and cellulose may be contained in an amount of 30 wt% or less relative to 100 wt% of pullulan. The composition ratio may contribute to optimizing the viscosity of the mixed solution during the film formation process and maintaining a homogeneous network structure within the film.

[0083] According to various embodiments, the mixed solution of the present invention may be composed of a combination of main raw materials including plurane, carboxymethylcellulose, and cellulose, and auxiliary raw materials for controlling the mechanical strength, flexibility, and solubility properties of the film. The water-dissociable film of the present invention may be configured to secure the structural stability of the film through the interaction between the main raw materials, and to more precisely control the physical properties of the film by adding auxiliary raw materials.

[0084] According to an embodiment, the auxiliary materials included in the mixed solution may include at least one of carrageenan, cyclodextrin, sorbitol, and glycerin. Carrageenan, a natural polysaccharide, can increase viscosity within the film and play a role in controlling the dissolution rate, and cyclodextrin can play a role in enhancing the strength and durability of the film by reinforcing the hydrogen bond network. In addition, sorbitol and glycerin can improve the flexibility of the film and contribute to maintaining appropriate elasticity even after the film is dried.

[0085] According to an embodiment of the present invention, the auxiliary raw material may be included in an amount of about 100 parts by weight (preferably 100 parts by weight or less) relative to 100 parts by weight of the main raw material, and may be configured to maintain a balance between the mechanical strength and dissolution properties of the film by being blended in an appropriate ratio within the mixed solution. In addition, the content of the auxiliary raw material may serve as an important factor in controlling the final physical properties of the film, and an optimal blending ratio may be derived to secure a certain degree of water dissociation while maintaining the durability of the film.

[0086] For example, carrageenan may be included in an amount ranging from 0.1 to 2.0 parts by weight relative to the total of the main and auxiliary ingredients, and may serve to increase the viscosity of the film and control the dissolution rate. If the content of carrageenan is excessive, the viscosity of the film may increase excessively, which may reduce uniformity during the application process. Conversely, if the content is too low, the structural stability of the film may be reduced.

[0087] Furthermore, in one embodiment, cyclodextrin is a cyclic oligosaccharide having a hydrophilic exterior and a hydrophobic interior, and serves to reinforce the hydrogen bond network within the film of the present invention, thereby improving the strength and durability of the film. For example, when the content of cyclodextrin is included in the range of 0.5 to 5.0 parts by weight relative to the total of the main and auxiliary materials, the physical properties of the film are balanced, and when the content is excessively large or small, the tensile strength and flexibility of the film may be affected.

[0088] In particular, cyclodextrin has the characteristic of forming hydrogen bonds with sodium ions, which plays a crucial role in strengthening 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 simultaneously, the sodium ions (Na) of CMC bind to cyclodextrin, reinforcing the network structure.

[0089] In this process, the porous structure of cyclodextrin promotes the formation of hydrogen bonds within the film, and the carboxymethyl group (-COO) of CMC - ) and sodium ions (Na + ) binds to the hydroxyl group (-OH) of cyclodextrin to form a stable polymer network. This binding method is CMC-Na + It can further increase the structural stability of the film compared to when it exists alone, and can effectively improve the physical strength compared to existing PVA-based films.

[0090] Furthermore, since cyclodextrin has a structure capable of forming numerous hydrogen bonds, it can interact with pullulan and CMC to form a denser network within the film. If the cyclodextrin content exceeds the appropriate range, excessive hydrogen bonding may occur, resulting in an excessive increase in the tensile strength of the film, which may reduce flexibility and make the film brittle. Conversely, if the cyclodextrin content is too low, the network formation within the film may be incomplete, preventing sufficient structural stability.

[0091] In an embodiment of the present invention, cyclodextrin is included in a range of 0.5 to 5.0 parts by weight to optimize the hydrogen bond network of the film and maintain a balance between strength and flexibility. In particular, cyclodextrin is CMC-Na + And the multiple hydrogen bonding network formed by combining with cellulose can contribute to maintaining uniform physical properties of the film and controlling interaction with water.

[0092] Additionally, in the embodiment, sorbitol and glycerin may be included in an amount ranging from 0.5 to 10.0 parts by weight, respectively, which may contribute to improving the flexibility of the film and maintaining appropriate elasticity even after drying. If the content of sorbitol and glycerin is excessive, the surface of the film may become sticky, and conversely, if the content is too low, the film may be excessively hardened, resulting in increased brittleness.

[0093] In an embodiment of the present invention, by blending the above-mentioned auxiliary raw materials in a ratio of about 100 parts by weight (preferably 100 parts by weight or less) to 100 parts by weight of the main raw materials (pulran, CMC, cellulose), the mechanical strength, flexibility, and water dissociation property of the film can be balanced.

[0094] In particular, the mixed solution of the present invention can be configured to provide excellent physical properties by utilizing environmentally friendly ingredients while resolving difficulties in controlling mechanical strength and dissolution rate that appear in existing polyvinyl alcohol (PVA)-based films.

[0095] In this example, pulani acts as a component that forms the main skeleton of the film and can provide excellent film-forming ability. Carboxymethylcellulose controls the viscosity of the mixed solution and enables uniform application during the film-forming process, and cellulose provides high mechanical strength, which can enhance the durability of the film.

[0096] In addition, the mixed solution of the present invention can be stirred at a constant temperature (e.g., 50 to 80°C) to form a homogeneous solution, and in the process, as hydrogen bonds are formed between pulani and CMC, the network structure within the film can be stably maintained.

[0097] In particular, by controlling the viscosity of the mixed solution to a range of 1,500 centipoise (cps) or more and 6,500 centipoise or less, the tensile strength of the film can be optimized and the mechanical strength can be uniformly maintained. In a more specific embodiment, the viscosity of the mixed solution is preferably 2,200 centipoise or more and 3,000 centipoise or less. This corresponds to a range similar to the viscosity of the mixed solution of a PVA-based film (e.g., 2710 cps), and is effective in maintaining uniform formation of the film and appropriate mechanical strength. That is, by controlling the viscosity of the mixed solution to a level similar to that of a PVA-based film (in a range of about 2,200 cps to 3,000 cps), the flexibility and processability of the film can be maintained while securing the mechanical strength.

[0098] In some embodiments, if the viscosity is excessively low, the fluidity of the mixed solution increases, resulting in insufficient network formation within the film, which may deteriorate the structural stability of the film. Conversely, if the viscosity is excessively high, the mixed solution gels, causing coagulation within the film. This makes it difficult to form a uniform network, which may result in uneven tensile strength.

[0099] In an embodiment of the present invention, by adjusting the viscosity of the mixed solution to an appropriate range, the hydrogen bonding between pullulan, carboxymethylcellulose (CMC), and cellulose can be optimized during the film forming process, and accordingly, the tensile strength of the resulting film can have a range of 20 N or more and 50 N or less.

[0100] In a more specific embodiment, in order to secure mechanical strength similar to that of a PVA-based film while maintaining solubility and environmental friendliness, it is preferable that the tensile strength be in the range of 35 N or more and 45 N or less.

[0101] This is an appropriate range that allows the water-dissociable film of the present invention to secure structural stability while maintaining mechanical strength compared to a PVA-based film (e.g., 44.80 N). If the tensile strength is less than 35 N, the durability of the film may be reduced, and if it exceeds 45 N, the flexibility of the film may be reduced. Therefore, by securing an optimal tensile strength range of 35 N to 45 N through the composition of the present invention, a film with a balanced mechanical strength and water-dissociability can be provided.

[0102] According to various embodiments, the mixed solution of the present invention may be characterized by comprising an additional raw material including a surfactant, and when the additional raw material is included, the final viscosity has a range of 15,000 centipoise or more and 30,000 centipoise or less.

[0103] In an embodiment, the additional raw material may include a cosmetic raw material, a functional additive, an active ingredient, a moisturizer, a biodegradation accelerator, a bioactive ingredient, and other raw materials that can be used industrially as ingredients for controlling the properties of the film.

[0104] For example, when a surfactant is included as an additional raw material, the film can be utilized as a cosmetic sheet such as a cleansing sheet. In addition, when a sodium component such as sodium carbonate is included, it can be manufactured in the form of a sheet having water-soluble properties, so that it can be utilized for various purposes. Through this composition, the functionality of the film can be adjusted and applied to suit specific industrial needs. Specifically, in an embodiment of the present invention, one or more of a moisturizer (e.g., hyaluronic acid, glycerin, propylene glycol), an antioxidant (e.g., vitamin C derivative, tocopherol), a physiologically active ingredient (e.g., peptide, flavonoid), a surfactant (e.g., lecithin, sodium lauryl sulfate), a functional additive (e.g., zinc oxide, titanium dioxide), and other components capable of industrial application can be included as additional raw materials.

[0105] In particular, the mechanical strength and flexibility of the film can be changed as the final viscosity of the film is adjusted when additional raw materials are included, and the film can be configured to control the dissolution rate and release of specific components.

[0106] For example, if a humectant is included to control moisture content, the flexibility of the film can be increased and the tensile strength can be controlled, and if a surfactant is included, the dissolution rate of the film can be adjusted.

[0107] Additionally, if the final viscosity is adjusted to 15,000 cps or higher, the network formation within the film can be more solid, and the strength and durability of the film can be improved. However, if the viscosity exceeds 30,000 cps, the viscoelasticity of the solution increases excessively, which can reduce processability during the film formation process. Conversely, if the viscosity is lower than 15,000 cps, the mechanical strength of the film may be reduced.

[0108] That is, when additional raw materials are included in the mixed solution of the present invention, the mechanical strength, flexibility, and dissolution characteristics of the film can be controlled, and optimal physical properties can be secured by maintaining the final viscosity at 15,000 cps or more and 30,000 cps or less. The functionality of the film can vary depending on the composition and ratio of the additional raw materials, and when specific components are included, it is possible to adjust the water dissociation rate and release behavior of the film.

[0109] Additionally, in an embodiment, a method for manufacturing a water-soluble film comprising cellulose may include a step (S200) of applying a mixed solution to a flat plate. The application process may include steps for forming a uniform thickness of the film and optimizing tensile strength and water-soluble properties.

[0110] Specifically, the mixed solution can be quantitatively applied onto a flat plate (e.g., glass plate, silicon mold, metal plate, etc.) so as to maintain uniform film thickness and mechanical strength, and the application process can be performed while maintaining a strategically set viscosity (1,500 cps to 6,500 cps or 15,000 cps to 30,000 cps when including additional raw materials).

[0111] According to an embodiment, the coating method may include at least one of casting, roll coating, doctor blade, or slot die coating. The casting method is primarily suitable for producing a uniform film in a laboratory environment, while roll coating or slot die coating may be applied for mass production.

[0112] After the coating process is completed, the mixed solution can be dried for a certain period of time at a temperature ranging from 40 to 60°C to form a film, during which the hydrogen bonding network between the plurane, carboxymethyl cellulose (CMC), cellulose, and other auxiliary materials can be strengthened. In addition, the coating thickness can affect the final mechanical properties and water dissociation properties of the film, and according to an embodiment, the thickness of the film can be set in the range of 20 μm to 200 μm, but is not limited thereto.

[0113] In an embodiment of the present invention, by controlling the viscosity of the mixed solution to an optimal range during the application process, it is possible to maintain a constant tensile strength even after the film is dried.

[0114] In addition, in an embodiment, a method for manufacturing a water-soluble film including cellulose may include a step (S300) of drying the applied mixed solution to form a water-soluble film.

[0115] According to an embodiment, the water-soluble film (100) of the present invention has a tensile strength in the range of 20 N or more and 50 N or less, which can be implemented in an environmentally friendly manner while maintaining mechanical strength similar to that of a conventional polyvinyl alcohol (PVA)-based film.

[0116] PVA-based films have been widely used in existing industries, but their environmental persistence has become a problem. The water-dissolvable film (100) of the present invention is designed to address this issue while still achieving tensile strength similar to that of existing PVA films.

[0117] More specifically, the applied mixed solution can be dried for a certain period of time at a temperature ranging from 40 to 60°C, during which the hydrogen bonding network between the plurane, carboxymethylcellulose, and cellulose can be strengthened. Furthermore, the drying speed and temperature can directly affect the mechanical properties of the film, and in embodiments of the present invention, the drying time can be set to a range of 2 hours or more and 24 hours or less.

[0118] The dried film is configured to maintain tensile strength while also maintaining water releasability, which can provide properties equivalent to or improved upon the physical properties of existing PVA-based films. In particular, unlike PVA films, the water releasable film of the present invention can secure mechanical strength through hydrogen bonding between natural polysaccharides without the use of a chemical cross-linking agent, and can be naturally decomposed after use.

[0119] In summary, as illustrated in FIG. 5, the method for manufacturing a water-dissociable film of the present invention may include a process of mixing a mixed solution containing pullulan, carboxymethylcellulose, and cellulose at about 75°C and then drying it at about 60°C to form a film. In the manufacturing process, a homogeneous solution is formed in the mixing step, and the mechanical strength and water-dissociability of the film can be controlled in the application and drying steps.

[0120] The hydrophilic film produced through the aforementioned process can have a multilayer structure, as illustrated in Fig. 6, in which fuluran forms the main skeleton of the film, CMC constitutes the internal network, and cellulose fibers provide structural support. This structural arrangement can increase the tensile strength of the film through hydrogen bonding and regulate hydrophilicity under specific temperature and humidity conditions.

[0121] The hydrophilic film of the present invention possesses properties similar to those of PVA-based films, yet can be constructed using environmentally friendly raw materials. Furthermore, the film's mechanical strength, flexibility, and dissolution properties can be controlled. Further details regarding this will be provided in the following experimental data.

[0122]

[0123] Experimental Method and Results Analysis (Experiment 1)

[0124] To evaluate the mechanical properties of the water-dissociable film of the present invention, tensile strength and viscosity measurements were performed. A PVA (polyvinyl alcohol)-based film was selected as a comparative group, which served as the basis for the experiment, and the properties of the water-dissociable film of the present invention were compared and analyzed with those of the pullulan, carboxymethyl cellulose, and cellulose-based films.

[0125]

[0126] 1. Experimental equipment and conditions

[0127] To evaluate the mechanical properties of the water-dissociable film of the present invention, tensile strength and viscosity measurements were performed. For tensile strength measurements, an Instron Korea 5569 universal testing machine was used, and a 1 kN load cell and air-pneumatic grips were used to secure the specimen. The test speed was set to 3,000 mm / min, and the specimens were manufactured to have a width of 10 mm, a thickness of 0.210 mm, and a length of 30 mm.

[0128] Viscosity measurements were performed using a CAS Model CL-R2 viscometer, and the experimental conditions were a rotation speed of 20 rpm and a measurement temperature of 25°C. Through this, the viscosity characteristics of the mixed solution of the present invention were evaluated, and the viscosity differences with various compositions combining pullulan, carboxymethyl cellulose (CMC), cellulose, and other cellulose derivatives (such as HPMC) were analyzed. Through this comparison, the effects on film formability, mechanical strength, and water dissociation were comprehensively evaluated.

[0129]

[0130] 2. Preparation of mixed solution and film formation

[0131] To evaluate the mechanical strength, viscosity, and water dissociation properties of the water-dissociable film of the present invention, mixed solutions of various compositions were prepared, and films were formed through a flat coating and drying process, and their physical properties were measured. For comparative experiments, a conventional PVA-based film (Comparative Example 1), a film of the present invention (Experimental Example 1), and films of various compositions (Experimental Example 2) were prepared and their physical properties were compared and analyzed.

[0132]

[0133] (1) Comparative Example 1: Manufacturing of PVA-based film and evaluation of physical properties

[0134] A conventional PVA-based film was manufactured and used as a benchmark for comparison with the film of the present invention. While polyvinyl alcohol (PVA) generally exhibits excellent water solubility and film-forming ability, it suffers from poor biodegradability and environmental sustainability as a chemically synthesized polymer. Therefore, using Comparative Example 1 as a benchmark, the film of the present invention was evaluated to assess its potential as an environmentally friendly alternative material while maintaining similar physical properties to PVA film.

[0135] - Composition: 12 wt% polyvinyl alcohol (PVA), 88 wt% distilled water

[0136] - Manufacturing method: Dissolve PVA in distilled water, apply the mixed solution to a flat plate, and dry to form a film.

[0137]

[0138] (2) Experimental Example 1: Manufacturing of the water-soluble film of the present invention and evaluation of its physical properties

[0139] The water-dissolvable film of the present invention is manufactured by combining pullulan, carboxymethylcellulose, and cellulose in specific ratios. In the present invention, pullulan serves to form the main skeleton of the film, CMC contributes to viscosity control and increased flexibility, and cellulose serves to reinforce the mechanical strength of the film.

[0140] - Composition: CMC and cellulose are each composed in an amount of 2 to 20 parts by weight relative to 100 parts by weight of pullulan. Specifically, the composition is composed of 80% by weight of pullulan, 10% by weight of CMC, and 10% by weight of cellulose relative to 100% by weight of the total composition.

[0141] - Manufacturing method: Mix pullulan, CMC, and cellulose in a certain ratio to prepare a mixed solution, then apply it to a flat plate and dry it to form a film.

[0142] The hydrophobic film of the present invention formed through the above process is as shown in Fig. 7.

[0143]

[0144] (3) Experimental Example 2: Experiment comparing various compositions

[0145] To compare with the optimal composition of the present invention, films were manufactured at various ratios. In Experimental Example 2, several combinations were established to determine changes in film properties according to changes in individual component compositions and additives.

[0146] In Experimental Example 2, hydroxypropyl methylcellulose (HPMC) was additionally utilized as a cellulose to enhance the structural stability of the film and control the viscosity of the solution, thereby enabling uniform film formation. HPMC is a widely used component in hydrogel sheets. It has the property of gelling the entire solution and can play a role in enhancing stability during the cold air process. Through this, the mechanical strength of the film was enhanced and its properties were secured under specific process conditions.

[0147]

[0148] ① Composition containing only flurane and CMC (1-1)

[0149] Composition: Contains only pullulan and CMC, excluding cellulose. The composition is composed by mixing pullulan and CMC in an 8:1 ratio.

[0150] Objective: To determine the effects of viscosity control and hydrogen bonding of CMC on the strength and hydrolysis properties of pulverized films.

[0151] The film produced by utilizing the composition formed through the composition is as shown in Fig. 8.

[0152]

[0153] ② Composition containing only pulani and cellulose (1-2)

[0154] Composition: Contains pullulan and cellulose, excluding CMC. The composition is composed by mixing pullulan and cellulose in an 8:1 ratio.

[0155] Purpose: To evaluate the changes in mechanical strength and physical properties of films when cellulose alone is added.

[0156]

[0157] ③ Composition containing pulane and other cellulose (HPMC) (1-3)

[0158] Composition: Contains pullulan and HPMC (hydroxypropyl methylcellulose), used in place of basic cellulose. The composition is composed by mixing pullulan and HPMC in an 8:1 ratio.

[0159] Objective: To analyze the effect of HPMC on hydrophilicity and mechanical strength.

[0160]

[0161] ④ Composition containing pulane, CMC, and other cellulose (HPMC) (1-4)

[0162] Composition: Composition containing flurane, CMC, and HPMC. Consists of flurane, CMC, and HPMC in an 8:1:1 ratio.

[0163] Objective: To determine the effect of combination between CMC and HPMC on film properties.

[0164]

[0165] ⑤ Composition containing pulane, CMC, cellulose, and other cellulose (HPMC) (1-5)

[0166] Composition: Composition containing pullulan, CMC, cellulose, and HPMC. Composition of pullulan, CMC, cellulose, and HPMC in an 8:1:1:1 ratio.

[0167] Objective: To analyze how the mechanical strength and hydrolytic properties of films change when four components are combined.

[0168]

[0169] ⑥ Composition containing only CMC and cellulose (1-6)

[0170] Composition: Composition consisting only of CMC and cellulose, excluding pulverane. The composition is composed by mixing CMC and cellulose in a 1:1 ratio.

[0171] Objective: To assess whether film formation is possible in the absence of flurane.

[0172]

[0173] ⑦ Composition including CMC, cellulose, and other celluloses (HPMC) (1-7)

[0174] Composition: Composition consisting only of CMC, cellulose, and HPMC, excluding fullerene. The composition is composed by mixing CMC, cellulose, and HPMC in a 1:1:1 ratio.

[0175] Objective: To evaluate the formability and properties of cellulose and HPMC-based films without pulverane.

[0176]

[0177] Meanwhile, in the experiment of the present invention, the water dissociation time was measured to compare the dissolution rate of the film, and based on this, the solubility was defined as rapidly dissolved (△), dissolved at a moderate rate (○), and dissolved very rapidly (◎).

[0178] ◎ (Dissolves very quickly): The film completely dissolves within 10 seconds.

[0179] ○ (Dissolves at normal speed): The film completely dissolves in 10 to 30 seconds.

[0180] △ (Slow dissolving): Takes more than 30 seconds, and some of the film remains after a certain amount of time.

[0181] - (Failure to dissolve or persists for a long time): Not completely dissolved even after 120 seconds

[0182]

[0183] The actual films formed by each composition method are as shown in Fig. 9. The actual films formed by each composition method are as shown in Fig. 9. Referring to Fig. 9, Comparative Example 1 (PVA-based film) has a transparent and uniform surface, and Experimental Example 1 (optimal composition of the present invention) also exhibits a relatively uniform film shape. Meanwhile, in Experimental Example 2, it was confirmed that the shape and surface characteristics of the film changed as the composition was modified, and in particular, in the composition containing HPMC, the film surface tended to have a porous structure. This is a result reflecting the gelation characteristics of HPMC, suggesting that it can increase film structural stability in certain compositions.

[0184]

[0185] 3. Results Analysis

[0186] In order to evaluate the mechanical strength, viscosity, and water dissociation of the water-dissociable film of the present invention, the physical properties were measured for Comparative Example 1 (PVA-based film), Experimental Example 1 (optimal composition of the present invention), and Experimental Example 2 (various variations of the composition), and the results are as follows.

[0187] NumberCompositionViscosity (cps, Sp4, 20 rpm)Tensile strength (N)Water dissociationComparative example 1PVA2,71044.80◎Experimental example 1Flurane + CMC + Cellulose2,35043.30◎1-1Flurane + CMC2,03014.31○1-2Flurane + Cellulose1,35019.64○1-3Flurane + Other cellulose (HPMC)1,71022.67△1-4Flurane + CMC + Other cellulose (HPMC)6,10029.29△1-5Flurane + CMC + Cellulose + Other cellulose (HPMC)6,13034.33△1-6CMC + Cellulose428Film formation failure-1-7CMC + Cellulose + Other cellulose (HPMC)514Film formation failure-

[0188] (1) Viscosity analysis

[0189] As a result of viscosity measurement, the viscosity of Comparative Example 1 (PVA-based film) was measured at 2,710 cps, and the viscosity of Experimental Example 1 (optimal composition of the present invention) was confirmed to be 2,350 cps. Compared to the PVA-based solution, the mixed solution of the present invention had a slightly lower viscosity, but maintained a viscosity level sufficient for film formation.

[0190] In Experimental Example 2, the viscosity varied widely as the composition was modified. The composition (1-1) containing pullulan and CMC and the composition (1-2) containing only pullulan and cellulose showed relatively low values ​​of 2,030 cps and 1,350 cps. This suggests that the viscosity control effect is limited when CMC and cellulose are added alone. On the other hand, the composition (1-3) containing pullulan and other cellulose (HPMC) and the composition (1-4) containing pullulan, CMC, and HPMC were measured to be 1,710 cps and 6,100 cps, respectively, indicating that the addition of HPMC causes a large viscosity change. In particular, the composition (1-5) containing pullulan, CMC, cellulose, and HPMC showed a very high viscosity of 6,130 cps, suggesting that the excessive increase in viscosity may make it difficult to uniformly apply the film.

[0191] For the compositions containing only CMC and cellulose (1-6) and only CMC, cellulose, and HPMC (1-7), the values ​​were 428 cps and 514 cps, respectively, suggesting that fullerene plays an important role in film formation.

[0192]

[0193] (2) Tensile strength analysis

[0194] As a result of the tensile strength measurement, the tensile strength of Comparative Example 1 (PVA-based film) was measured as 44.80 N, and the tensile strength of Experimental Example 1 (optimal composition of the present invention) was confirmed as 43.30 N. This means that the film of the present invention can secure a mechanical strength similar to that of a PVA-based film, suggesting the possibility of replacing existing PVA-based films.

[0195] In Experimental Example 2, the tensile strength values ​​varied widely as the composition was modified. The composition (1-1) containing only pullulan and CMC showed a relatively low mechanical strength of 14.31 N, and the composition (1-2) containing only pullulan and cellulose showed a relatively low mechanical strength of 19.64 N. This shows that the mechanical strength reinforcing effect is limited when cellulose and CMC are added alone.

[0196] On the other hand, the composition (1-3) containing pullulan and other cellulose (HPMC) was confirmed to be 22.67 N, and the composition (1-4) containing pullulan, CMC, and HPMC was confirmed to be 29.29 N, showing a tendency for mechanical strength to improve when HPMC was included. In particular, the composition (1-5) containing pullulan, CMC, cellulose, and HPMC showed the highest strength at 34.33 N, but there is a possibility that viscosity increase and application uniformity problems may occur.

[0197] For the compositions containing only CMC and cellulose (1-6) and only CMC, cellulose, and HPMC (1-7), tensile strength measurement was not possible, indicating that fullerene plays an essential role in film formation and securing mechanical strength.

[0198]

[0199] (3) Evaluation of water dispersibility

[0200] As a result of the water dissolution evaluation, Comparative Example 1 (PVA-based film) was completely dissolved (◎) within 10 seconds, and Experimental Example 1 (optimal composition of the present invention) was also completely dissolved (◎) within 10 seconds, showing a dissolution rate similar to that of the PVA-based film.

[0201] In Experimental Example 2, the solubility varied in various ways as the composition was modified, and the composition (1-1) containing only pullulan and CMC and the composition (1-2) containing only pullulan and cellulose completely dissolved (○) in 10 seconds or more and 30 seconds or less, showing relatively fast solubility.

[0202] On the other hand, compositions containing pullulan and other cellulose (HPMC) (1-3), compositions containing pullulan, CMC, and HPMC (1-4), and compositions containing pullulan, CMC, cellulose, and HPMC (1-5) took more than 30 seconds and showed a tendency for a certain amount of film to remain (△). This is interpreted as a decrease in the dissolution rate as the structural strength of the film increases when HPMC is included.

[0203] For the compositions containing only CMC and cellulose (1-6) and the compositions containing only CMC, cellulose, and HPMC (1-7), film formation failed, making solubility evaluation impossible.

[0204]

[0205] (4) Derivation of optimal composition

[0206] As a result of a comprehensive analysis of this experiment, it was confirmed that Experimental Example 1 (composition of pulverane, CMC, and cellulose) achieved the optimal balance in terms of viscosity (2,350 cps), tensile strength (43.30 N), and water dissociation (◎).

[0207] This composition was confirmed to be environmentally friendly compared to existing PVA while maintaining mechanical strength similar to that of PVA-based films, and the dissolution rate was also maintained at the same level as that of existing PVA films.

[0208] Additionally, referring to FIG. 10, a tensile stress-strain curve of a film manufactured with the optimal composition of the present invention is illustrated. As can be seen in the graph, the hydrolyzable film of the present invention exhibits a rapid stress increase in the initial elastic range, exhibits a maximum tensile strength of approximately 20 MPa, maintains the stress at a certain level, and then fracture occurs at a strain of approximately 70%.

[0209] Meanwhile, if the tensile strength value in MPa is converted to suit the experimental conditions, it is as follows. The cross-sectional area (width Х thickness) of the specimen used in this experiment is 10 mm Х 0.21 mm = 2.1 mm² = 2.1 Х 10 -6 m². Therefore, 20 MPa (= 20 N / mm²) Х 2.1 mm² = 42 N, which means that the film of the present invention can withstand a maximum tensile load of about 42 N.

[0210] These characteristics exhibit mechanical properties similar to those of PVA-based films, suggesting that the film's durability and tensile strength can be secured while optimizing its dissolution rate. In particular, the relatively wide stress-maintaining region after the elastic region indicates that the composition of the present invention is effective in maintaining film durability, and the interaction between the pullulan, CMC, and cellulose can be interpreted as increasing the stability of the film structure.

[0211] As described above, the water-dissociable film utilizing the plurane-CMC-cellulose combination of the present invention has been confirmed to be implemented using an environmentally friendly material while maintaining mechanical strength equivalent to that of conventional PVA-based films. In particular, mechanical strength can be maintained by utilizing plurane as the main skeleton of the film, inducing viscosity control and homogeneous film formation through CMC, and adding cellulose as a reinforcing material.

[0212] Furthermore, the film of the present invention exhibits a water dissociation rate similar to that of PVA-based films and exhibits rapid dissolution upon contact with water. This suggests its potential as a replacement for existing PVA-based products in environmentally friendly water-dissociable packaging and disposable film applications.

[0213] Additionally, the film manufacturing process of the present invention has the advantage of not requiring a high-temperature process and being easy to combine with various auxiliary raw materials (moisturizing agent, functional additive, etc.).

[0214] For example, when a surfactant is additionally included in a composition (pulran, carboxymethylcellulose, and cellulose) according to an embodiment of the present invention, it can be utilized as a cosmetic sheet, such as a cleansing sheet. The film manufactured using this composition can be formed into a shape as illustrated in Fig. 11, and can be configured to have a soft texture and appropriate water dissociation properties, making it suitable for cleansing and cosmetic applications.

[0215] Through this, it can be used in various industrial applications such as food packaging materials, medical films, cosmetic sheets, and functional dissolving films, and it has value as an eco-friendly alternative material with superior biodegradability and improved chemical stability compared to existing synthetic polymer films.

[0216] As a result, the water-dissociable film based on the plurane-CMC-cellulose of the present invention overcomes the limitations of existing PVA-based films and provides an optimal composition that simultaneously satisfies environmental friendliness, mechanical stability, and rapid dissolution, thereby suggesting a new solution with high applicability in various industrial fields.

[0217]

[0218] Experimental Method and Results Analysis (Experiment 2)

[0219] To evaluate the mechanical properties of the water-dissociable film based on the pullulan-CMC-cellulose of the present invention according to the relative proportions of the main components, tensile strength and viscosity measurements were performed. The experiments were conducted when CMC and cellulose were each in the range of 1 to 25% by weight relative to pullulan. The experimental conditions and methods were the same as those in Experiment 1, and the experimental results are as follows.

[0220] Number Composition Tensile strength (N) Water dissociation Experimental example 1 CMC is 1% of flurane Cellulose is 1% of flurane 21.21 ○ Experimental example 2 CMC is 2% of flurane Cellulose is 2% of flurane 35.80 ◎ Experimental example 3 CMC is 5% of flurane Cellulose is 5% of flurane 39.02 ◎ Experimental example 4 CMC is 12.5% ​​of flurane Cellulose is 12.5% ​​of flurane 43.30 ◎ Experimental example 5 CMC is 20% of flurane Cellulose is 20% of flurane 47.66 ○ Experimental example 6 CMC is 22% of flurane Cellulose is 22% of flurane 49.90 △

[0221] It can be seen that the water dissociation property slightly decreases when the cellulose and CMC content reaches 20%, and becomes very poor when it reaches 22%. This is analyzed to be because the strength becomes very strong as the amount of cellulose increases, and galling occurs a lot as the amount of CMC increases. In addition, in the case of Experimental Example 1 with 1% cellulose and CMC, it can be seen that the tensile strength decreases rapidly compared to Experimental Example 2. When the tensile strength falls below 25 N, a problem occurs in which it becomes difficult to maintain the film form.

[0222] As a result, it can be seen that when CMC and cellulose are mixed at 2 to 20% relative to pulverane, they have the appropriate tensile strength for water dissociation and film formation.

[0223]

[0224] While the embodiments of the present invention have been described above with reference to the attached drawings, those skilled in the art will appreciate that the present invention can be implemented in other specific forms without altering the technical concept or essential features thereof. Therefore, the embodiments described above should be understood to be illustrative in all respects and not restrictive.

[0225] The specific implementations described in the present invention are exemplary embodiments and do not limit the scope of the present invention in any way. For the sake of brevity, descriptions of conventional electronic components, control systems, software, and other functional aspects of the systems may be omitted. In addition, the lines connecting or connecting members between components depicted in the drawings are merely representative of functional connections and / or physical or circuit connections, and may be replaced or represented as various additional functional connections, physical connections, or circuit connections in an actual device. In addition, unless specifically mentioned as "essential," "important," etc., a component may not be absolutely necessary for the application of the present invention.

[0226] It should be understood that the specific order or hierarchy of steps in the presented processes is merely an example of exemplary approaches. It should be understood that the specific order or hierarchy of steps in the processes may be rearranged within the scope of the present invention based on design priorities. The appended method claims provide elements of various steps in a sample order, but are not intended to be limited to the specific order or hierarchy presented.

[0227] The description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments disclosed herein, but is to be construed in the broadest scope consistent with the principles and novel features disclosed herein.

[0228]

[0229] The best mode for carrying out the invention as described above has been described.

Claims

1. A water-dissolvable film containing cellulose, The above water-dissociable film is characterized by including pullulan, carboxymethyl cellulose (CMC) and cellulose. A hydrolyzable film containing cellulose.

2. In paragraph 1, The above water-soluble film is, The carboxymethyl cellulose is included in an amount of 2 parts by weight or more and 20 parts by weight or less based on 100 parts by weight of the above-mentioned flurane, A water-dissociable film comprising cellulose, characterized in that the cellulose is contained in an amount of 2 parts by weight or more and 20 parts by weight or less relative to 100 parts by weight of the above-mentioned pulaniol.

3. In paragraph 1, The above water-soluble film is, Characterized in that it is formed using a mixed solution having a viscosity in the range of 1,500 centipoise (cps) or more and 6,500 centipoise or less, A hydrolyzable film containing cellulose.

4. In paragraph 1, The above water-soluble film is, Characterized in that the tensile strength is in the range of 20N or more and 50N or less, A hydrolyzable film containing cellulose.

5. In paragraph 1, The above water-soluble film is, Characterized in that it forms an intermolecular hydrogen bonding network between the above-mentioned pulran and the above-mentioned carboxymethylcellulose. A hydrolyzable film containing cellulose.

6. In paragraph 1, The above water-soluble film is, It comprises a main raw material including the above-mentioned pulran, the above-mentioned carboxymethyl cellulose and the above-mentioned cellulose, and an auxiliary raw material for controlling the mechanical strength, flexibility and dissolution properties of the film, characterized in that the auxiliary raw material is included in an amount of 100 parts by weight or less based on 100 parts by weight of the main raw material. A hydrolyzable film containing cellulose.

7. In paragraph 6, The above raw materials are, Containing at least one of Carrageenan, Cyclodextrin, Sorbitol and Glycerin, A hydrolyzable film containing cellulose.

8. In paragraph 1, The above water-soluble film is, It may contain additional raw materials including surfactants, in which case the final viscosity is characterized by a range of 15,000 centipoise or more and 30,000 centipoise or less. A hydrolyzable film containing cellulose.

9. In a method for manufacturing a water-soluble film containing cellulose, A step of preparing a mixed solution containing pullulan, carboxymethylcellulose and cellulose; A step of applying the above mixed solution to a flat plate; and A step of drying the applied mixed solution to form a water-soluble film; including, A method for producing a water-dissolvable film comprising cellulose.

Images