Polysaccharide-containing film, and method for producing said film

Abstract

The present invention provides a skin bonding member that can be simplified and streamlined in terms of handleability, an application method, a skin bonding member configuration (component configuration and layer configuration), etc.　Provided is a film that contains a polysaccharide (A) having a sulfate group and sodium hyaluronate (B).

Description

Polysaccharide-containing film and method for producing said film

[0001] The present invention relates to a polysaccharide-containing film and a method for producing the film.

[0002] In today's living environment, the need to protect and maintain healthy skin is increasing due to factors such as the deterioration of daily routines during the COVID-19 pandemic, the constant use of masks, and the effects of environmental pollution. Women in East Asia, in particular, have long had a continuing need to whiten their skin (so-called skin whitening) and maintain its moisture. Cosmetics are generally composed of various ingredients and are designed to balance their performance. For example, simplifying the application method and composition of cosmetic ingredients would enable greater flexibility in cosmetic design and efficacy. Furthermore, in the field of skin adhesive devices aimed at enhancing skin moisturizing effects, including cosmetics and medical preparations, there is a need for skin adhesive devices with simpler configurations. A skin adhesive laminate is known, which comprises a layer containing polysaccharides derived from Aphanothece sacrum on a support (see, for example, Patent Document 1). Also known is a skin adhesive film formed by forming a composition containing Aphanothece sacrum polysaccharide (a), water (b), and a polyhydric alcohol (c) into a film (see, for example, Patent Document 2).

[0003] JP 2018-177744 A JP 2018-199654 A

[0004] Amorphophallus saccharinus polysaccharides have a high film-forming ability, and thus have the advantage of easily obtaining a uniform film when formed into a film. However, it has been found that films formed using Amorphophallus saccharinus polysaccharides alone have weak strength and are prone to rupture. The skin adhesive laminate described in Patent Document 1 requires a layer containing Amorphophallus saccharinus-derived polysaccharides as well as a support to support the layer. From the standpoints of ease of application and ease of handling, it is desirable for the skin adhesive member to be composed solely of a layer containing Amorphophallus saccharinus polysaccharides without using a support. Furthermore, the gel film described in Patent Document 2 containing Amorphophallus saccharinus polysaccharides, water, and a polyhydric alcohol is easy to prepare, but suffers from problems of poor post-processing and handling. From the viewpoint of providing a skin adhesive member with simpler and easier handling, application method, and configuration of the skin adhesive member (component configuration, layer configuration, etc.), the skin adhesive members described in Patent Documents 1 and 2 above are not sufficient and there is room for improvement. Therefore, an object of the present invention is to provide a skin adhesive member that can be simplified and easier from the viewpoint of handling, application method, configuration of the skin adhesive member (component configuration, layer configuration, etc.).

[0005] As a result of extensive research to solve the above problems, the present inventors discovered a film characterized by containing a polysaccharide (A) having a sulfate group and sodium hyaluronate (B), thereby solving the above problems.

[0006] That is, the present invention encompasses the following aspects. [1] A film containing a polysaccharide (A) having sulfate groups and sodium hyaluronate (B). [2] The film according to [1], wherein the polysaccharide (A) having sulfate groups is a polysaccharide having a weight-average molecular weight in the range of 3,000,000 to 30,000,000. [3] The film according to [1] or [2], wherein the content ratio of the polysaccharide (A) having sulfate groups to the sodium hyaluronate (B) is 80:20 to 20:80 in terms of the mass ratio of [polysaccharide (A) having sulfate groups]:[sodium hyaluronate (B)]. [4] The film according to any one of [1] to [3], wherein the combined mass ratio of the polysaccharide (A) having sulfate groups and the sodium hyaluronate (B) in the film is 70% or more. [5] The film according to any one of [1] to [4], wherein when the film contains another component (D) in addition to the polysaccharide (A) having sulfate groups, the sodium hyaluronate (B), and, if contained, water (C), the mass proportion of the other component (D) in the film is 10% or less. [6] The film according to any one of [1] to [5], wherein the polysaccharide (A) having sulfate groups is a polysaccharide obtained from Aphanothece sacrum. [7] The film according to any one of [1] to [6], wherein the film is used as a skin adhesive member. [8] A method for producing a film, comprising the steps of: preparing an aqueous solution (I) containing a polysaccharide (A) having a sulfate group; preparing an aqueous solution (II) containing sodium hyaluronate (B); mixing the aqueous solution (I) and the aqueous solution (II) to obtain a mixed solution (III); and disposing the mixed solution (III) on a substrate to form a coating film on the substrate, and then evaporating the water in the coating film to dry the coating film, thereby obtaining the film according to any one of [1] to [7].

[0007] The present invention can provide a skin adhesive member that can be simplified and made easier from the standpoints of handling, application method, and the structure of the skin adhesive member (component structure and layer structure).

[0008] 1 is a photograph for explaining the state of a film during formation and the state of a film after film formation in Examples and Comparative Examples.

[0009] The present invention will be described in detail below. Note that the following explanation of the constituent elements is an example for explaining the present invention, and the present invention is not limited to these contents.

[0010] (Film) The film of the present invention contains a polysaccharide having a sulfate group (A) and sodium hyaluronate (B). The film of the present invention may contain water (C) and other components (D) in addition to the polysaccharide having a sulfate group (A) and the sodium hyaluronate (B).

[0011] The film of the present invention is the mixture of polysaccharide (A) with sulfate group and sodium hyaluronate (B) formed into film, and the layer that contains polysaccharide (A) with sulfate group and sodium hyaluronate (B) can be formed into thin film structure by itself without the existence of support after forming.For example, the thing that can keep flexibility such as being able to be wound into roll shape is called "film" in the present invention, but the thing that cannot be wound into roll shape even if it tries to be wound, or the layer has poor strength or flexibility, such as being cut in the middle, and cannot keep thin film structure by itself cannot be called "film" in the present invention.

[0012] The film of the present invention is intended to have a thickness on the order of μm, and the thickness of the film of the present invention is preferably 1 to 200 μm, more preferably 1 to 100 μm, still more preferably 1 to 50 μm, and even more preferably 5 to 40 μm.

[0013] <Polysaccharide (A) Having Sulfate Groups> The polysaccharide (A) having sulfate groups used in the present invention may be any polysaccharide having sulfate groups in part thereof, and is not particularly limited as long as the effects of the present invention can be obtained. However, polysaccharides (A) having 1 to 30 moles of sulfate groups per 10 moles of constituent sugars are more preferred. Polysaccharides (A) having sulfate groups in this range relative to the constituent sugars of the polysaccharide are preferred because they exhibit good hydration ability over a wide range of pH environments. As the polysaccharide (A) having sulfate groups, sulfate group-containing polysaccharides extracted from various raw materials may be used as they are, or polysaccharides obtained by introducing sulfate groups into polysaccharides that do not contain sulfate groups using known methods may also be used. Furthermore, salts of these polysaccharides may also be used as the polysaccharide (A) having sulfate groups in its structure. The sulfate groups contained in the polysaccharide (A) having sulfate groups can be determined by elemental analysis, quantifying the sulfur atom content relative to the carbon atom content.

[0014] As the polysaccharide (A) having sulfate groups used in the present invention, polysaccharides having sulfate groups derived from cyanobacteria are preferred, and in particular, Aphanothece sacrum polysaccharide derivatives obtained from Aphanothece sacrum (scientific name: Aphanothece sacrum) are preferred because they improve dispersion stability.

[0015] In the present invention, A. saccharinum, a suitable source of sulfate-containing polysaccharide (A), is a type of photosynthetic eubacterium belonging to the Chroococcales order of cyanobacteria. A. saccharinum is a freshwater cyanobacterium native to a specific region of Kyushu, forming flat colonies of multiple cells. The outer surface of the colonies is covered with a gel-like secretion formed from polysaccharides and other substances, and the colonies grow to a diameter of approximately 50 mm. A. saccharinum has been prized as a food since ancient times, is a widely consumed ingredient, and its safety is guaranteed.

[0016] Specific methods for extracting the sulfate-containing polysaccharide (A) from A. saccharinum include freezing an appropriate amount of A. saccharinum and washing it with water to remove water-soluble pigments, then removing fat-soluble pigments with an organic solvent such as ethanol, and drying the A. saccharinum algae. 0.1 N sodium hydroxide is then added to the resulting dried A. saccharinum algae, followed by stirring at 60 to 80°C for 6 hours. The sugar derivative solution obtained by the above procedure is neutralized and filtered, and further treated with a dialysis membrane with a molecular weight cutoff of 8,000, and the solution inside the dialysis membrane is concentrated and dried.

[0017] The polysaccharide derived from Aphanothece sacrum used in the present invention is also known as "Sakuran" (registered trademark of Green Science Materials Co., Ltd.).

[0018] Furthermore, the polysaccharide (A) having a sulfate group used in the present invention may be, in addition to polysaccharides derived from Aphanothece sacrum, one or more selected from the group consisting of heparan sulfate, chondroitin sulfate, dermatan sulfate, and salts thereof; or one or more selected from the group consisting of known polysaccharides composed of D-glucosamine, D-galactosamine, D-glucuronic acid, L-iduronic acid, D-galacturonic acid, D-glucose, D-galactose, D-xylose, etc., having a sulfate group in a portion thereof, and salts thereof. These components may be used alone, or two or more may be used in appropriate combination.

[0019] The weight-average molecular weight of the polysaccharide (A) having sulfate groups used in the present invention is not particularly limited as long as the effects of the present invention can be obtained, but is preferably 3,000,000 to 30,000,000, more preferably 3,500,000 to 25,000,000, even more preferably 3,500,000 to 20,000,000, and particularly preferably 4,000,000 to 15,000,000.

[0020] <Sodium hyaluronate (B)> The weight-average molecular weight of the sodium hyaluronate (B) used in the present invention is not particularly limited as long as the effects of the present invention can be obtained, but it is preferably 600,000 to 2,500,000, and more preferably 1,200,000 to 2,000,000.

[0021] The polysaccharide (A) having sulfate groups has a high film-forming function. When the polysaccharide (A) having sulfate groups is used alone to form a film, it is easy to obtain a uniform film, but the film is weak in strength and easily breaks, and the film does not have durability. Therefore, in the present invention, sodium hyaluronate (B) is added. By forming a film using the polysaccharide (A) having sulfate groups and sodium hyaluronate (B), a film with excellent uniformity and high strength can be obtained. Because the polysaccharide (A) having sulfate groups has an ultra-high molecular weight, it is difficult to obtain mechanical strength (torsion strength (bending strength)) by itself, but it is presumed that by blending with sodium hyaluronate, which is the same polysaccharide, the dispersion balance between resins is improved, and the mechanical strength of the film can be improved.

[0022] <The content ratio of polysaccharides (A) with sulfate group and sodium hyaluronate (B)> As mentioned above, the film of the present invention contains the polysaccharides (A) with sulfate group and sodium hyaluronate (B), so it becomes a film with excellent uniformity and high strength.However, it has been found that when sodium hyaluronate is used alone to form a film, film shrinkage becomes a problem.If sodium hyaluronate is contained in an excessively large amount, film shrinkage becomes a problem.Therefore, in order to compensate for the weakness of polysaccharides (A) with sulfate group (weakness of film strength) and the weakness of sodium hyaluronate (B) (film shrinkage) when forming a film, and obtain a uniform and high-strength film without shrinkage, it is desirable to adjust the content ratio of polysaccharides (A) with sulfate group and sodium hyaluronate (B). In the film of the present invention, for example, the content ratio of the sulfate group-containing polysaccharide (A) to the sodium hyaluronate (B) is preferably 80:20 to 20:80, more preferably 75:25 to 25:75, and even more preferably 70:30 to 50:50, in terms of the mass ratio of the sulfate group-containing polysaccharide (A):sodium hyaluronate (B). A film having a content ratio of the sulfate group-containing polysaccharide (A) to the sodium hyaluronate (B) within the above range can be made into a uniform film with high strength and no shrinkage. Because the sulfate group-containing polysaccharide (A) has an ultra-high molecular weight, it is difficult to achieve sufficient mechanical strength (torsional strength (flexural strength)) when used alone. However, it is believed that blending the sulfate group-containing polysaccharide (A) with sodium hyaluronate, another polysaccharide, in a preferred amount improves the dispersion balance between the resins, thereby improving the mechanical strength of the film while suppressing the shrinkage of the sodium hyaluronate.

[0023] In the film of the present invention, the total mass ratio of the polysaccharide (A) with sulfate group and sodium hyaluronate (B) is preferably 70% or more, more preferably 80%, more preferably 85%, more preferably 90%, even more preferably 95%, even more preferably 98%.The film of the present invention can be the film that is only composed of the polysaccharide (A) with sulfate group and sodium hyaluronate (B), and the total mass ratio of the polysaccharide (A) with sulfate group and sodium hyaluronate (B) is 100%.

[0024] The film of the present invention is preferably in a dry film state, but may contain a small amount of water as long as the film has enough strength to maintain its shape by itself even without a support. The content of water (C) in the film of the present invention is preferably 30% or less, more preferably 20% or less, even more preferably 10% or less, and particularly preferably 5 to 6% or less, calculated on a mass basis.

[0025] The film of the present invention may contain other component (D) as described above. When the film is used in the cosmetic or medical fields, examples of the other component (D) include any oil that can be used in the cosmetic or medical fields, moisturizers such as glycerin, anti-inflammatory components such as dipotassium glycyrrhizinate and allantoin, antioxidants such as ascorbic acid and its esters, astringents, whitening components, skin quality improving components, surfactants, UV protection agents, plant- and animal-derived extracts, higher alcohols, antioxidants, colorants, pH adjusters, fragrances, preservatives, and polysaccharides other than component (A).

[0026] In the film of the present invention, when other component (D) is contained in addition to the polysaccharide (A) having a sulfate group, sodium hyaluronate (B), and water (C), if contained, the mass proportion of other component (D) in the film is preferably 10% or less, more preferably 8% or less, and even more preferably 4 to 5% or less.

[0027] <Film manufacturing method> The film of the present invention can be obtained by molding (forming) a mixture of a polysaccharide (A) having sulfate groups and sodium hyaluronate (B) into a film. For example, a method of forming a film can be used that uses a solution (coating liquid) containing a polysaccharide (A) having sulfate groups and sodium hyaluronate (B). When using a coating liquid, the solid content is usually 0.05 to 0.5% by mass.

[0028] A more specific example of the method for producing the film of the present invention is a method comprising the following steps. The method for producing the film of the present invention comprises the steps of: preparing an aqueous solution (I) containing a polysaccharide (A) having a sulfate group; preparing an aqueous solution (II) containing sodium hyaluronate (B); mixing the aqueous solution (I) and the aqueous solution (II) to obtain a mixed solution (III); and disposing the mixed solution (III) on a substrate to form a coating film on the substrate, and then evaporating the water in the coating film to dry the coating film, thereby obtaining a film. Here, the drying conditions include, for example, 70°C or less and within 48 hours.

[0029] <Use of Film> The film of the present invention has excellent skin moisturizing properties and can be used appropriately in various applications requiring skin moisturizing properties, such as cosmetic films and masks for application to the skin, and skin adhesive materials for medical film preparations.

[0030] The film of the present invention may be not only a dry film, but also a wet film containing some moisture. As long as the presence of moisture does not cause the film to lose its strength as a layer, fail to form a film, or cause the film to break, the film may contain moisture as long as it can form a film that can maintain a thin-film structure as a single layer. The film of the present invention can be used by adhering it to the skin surface. A support is not required, and the film layer alone can be directly contacted and attached to the skin. To make the attachment to the skin more effective, moisture may be supplied to the film when applied to the skin to further improve the moist state of the film before adhering it to the skin. As described above, the film of the present invention can maintain a thin-film structure as a single layer, so a support is not required from the perspective of maintaining the shape of the film. However, for example, to prevent contact between films when wrapping the film or to consider convenience when applying the film to the user, the film of the present invention may be used in a configuration in which a film other than the film of the present invention, such as a release film, is laminated on the film of the present invention.

[0031] <Specific Uses of the Film> The film of the present invention can exhibit sustained-release properties by absorbing water, and this property can be utilized in various applications. For example, by incorporating a functional substance into the film of the present invention, the functional substance can be released over time from the film into the stratum corneum of the skin. Examples of functional substances include raw materials used in cosmetics. Examples of functional substances include vitamins and vitamin derivatives, hydroquinone and its derivatives, whitening ingredients, anti-inflammatory ingredients, antioxidant ingredients, blood circulation-promoting ingredients, cell-activating ingredients, coenzymes and their intermediate metabolites, sugars, plant extracts, peptides, proteins, and pigments. More specifically, examples include ascorbic acid, ascorbic acid esters, dipotassium glycyrrhizinate, allantoin, vitamin A, and vitamin E. The exemplary compounds listed here include not only water-soluble but also oil-based raw materials. As long as the functional substance impregnated into the film of the present invention is a functional substance that can be delivered to the skin over time due to the sustained-release property, there is no particular limitation on whether the functional substance is water-soluble or oil-based.

[0032] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0033] <Preparation of Polysaccharides Having Sulfate Groups> A frozen Aphanothece sacrum was thawed and then subjected to running water to remove impurities and water-soluble pigments. The Aphanothece sacrum was then stirred in an aqueous ethanol solution for 24 hours to remove fat-soluble pigments. The Aphanothece sacrum was then removed from the ethanol and exposed to a 0.05N aqueous sodium hydroxide solution heated to 40°C for 2 hours for hydrolysis, yielding an aqueous Aphanothece sacrum polysaccharide solution.

[0034] The aqueous solution of Aphanothece saccharin polysaccharide obtained by the above treatment was filtered using a filter cloth, and the filtrate was placed in a dialysis membrane with a molecular weight cutoff of 8,000 and dialyzed in distilled water until the pH of the dialysis solution reached approximately 9.0, thereby obtaining a solution of Aphanothece saccharin polysaccharide derivative.

[0035] The solution of the Aphanothece saccharin polysaccharide derivative was added to isopropanol and stirred to obtain a fibrous Aphanothece saccharin polysaccharide derivative.

[0036] The obtained Aphanothece saccharinum polysaccharide derivative was analyzed by a conventional method, and it was confirmed that the polysaccharide had 15 mol % of sulfate groups relative to sugar residues in the structure.

[0037] The obtained Aphanothece sacrum polysaccharide derivative was subjected to molecular weight fractionation by ultrafiltration to prepare a Aphanothece sacrum polysaccharide derivative having a weight average molecular weight of 5,000,000 to be used in the following examples.

[0038] <Preparation of aqueous solution of polysaccharide having sulfate groups and aqueous solution of sodium hyaluronate> A saccharin Aphanothece saccharin polysaccharide derivative with a weight-average molecular weight of 5 million as measured by multi-angle scattering GPC was weighed out, water was added, and the mixture was stirred with a stirrer at 80°C for 8 hours to prepare a 0.2 mass% aqueous solution of the saccharin Aphanothece saccharin polysaccharide derivative.

[0039] Sodium hyaluronate (weight average molecular weight 2,000,000) of polymeric polysaccharide was weighed out, water was added, and the mixture was stirred with a stirrer at 40°C for 1 hour to prepare a 0.2% by mass aqueous solution of sodium hyaluronate. Kikkoman Biochemifa Corporation's FCH-200 sodium hyaluronate was used.

[0040] (Example 1) Prepare 0.2 mass% Aphanothece sacrum polysaccharide derivative aqueous solution and 0.2 mass% sodium hyaluronate aqueous solution, and mix Aphanothece sacrum polysaccharide derivative aqueous solution: sodium hyaluronate aqueous solution = 75:25 (mass%).After mixing, pour 25g of this mixed solution into a 4.5cm x 4.5cm polystyrene Petri dish, and dry at normal pressure, 40 ℃, 24 hours, to obtain a non-shrinkage, uniform and high strength film.

[0041] <Shrinkage suppression evaluation> The area of ​​the obtained film was calculated as 100% relative to the area of ​​the Petri dish (4.5 cm x 4.5 cm). [Evaluation criteria] 4: The film area is 95% or more to 100% of the area of ​​the Petri dish 3: The film area is 90% or more to less than 95% of the area of ​​the Petri dish 2: The film area is 80% or more to less than 90% of the area of ​​the Petri dish 1: The film area is less than 80% of the area of ​​the Petri dish In each evaluation, a larger numerical value indicates a better result. For example, in the evaluation results, "4" indicates the best result, "3" indicates the next best result, and "1" indicates the worst result (the numerical values ​​in the other evaluation results have the same meaning).

[0042] <Evaluation of Rigidity (Bending Strength)> The film was folded from front to back and the number of times it was folded until it broke was evaluated. [Evaluation Criteria] 4: 9 times or more 3: 8 times or more but less than 9 times 2: 7 times or more but less than 8 times 1: 1 time or more but less than 7 times

[0043] <Film uniformity evaluation> The thickness was measured at a total of nine locations, three vertically and three horizontally, using a thickness gauge manufactured by Mitutoyo Corporation, and the film uniformity was evaluated based on the % variation from the average value. [Evaluation criteria] 4: Variation within ±10% 3: Variation greater than ±10% but within 20% 2: Variation greater than ±20% but within 30% 1: Variation greater than ±30%

[0044] The evaluation results of these tests are shown in Table 1. Photographs showing the film being placed in a polystyrene petri dish during film formation, and photographs showing the state of the film after film formation and when it was subjected to each evaluation test are shown in Figure 1. In Figure 1, the upper photograph in the column for Example 1 shows the state of the film during formation, and the lower photograph shows the state of the film after film formation.

[0045] (Examples 2 to 4) Films were obtained in the same manner as in Example 1, except that the ratio of the aqueous solution of Aphanothece sacrum polysaccharide derivative to the aqueous solution of sodium hyaluronate was changed to 70:30 (mass %), 50:50 (mass %), or 25:75 (mass %). Unshrunk, uniform, and strong films were obtained. The films were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1. In addition, the appearance of the films during formation and after film formation for Examples 2 to 4 is shown in Figure 1.

[0046] (Comparative Example 1) A film was obtained in the same manner as in Example 1, except that the ratio of the aqueous solution of the Aphanothece sacrum polysaccharide derivative to the aqueous solution of sodium hyaluronate was changed to 100:0 (mass%). The film was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1. In addition, for Comparative Example 1, the appearance of the film during formation and the film after film formation is shown in Figure 1.

[0047] (Comparative Example 2) A film was obtained in the same manner as in Example 1, except that the ratio of the aqueous solution of the Aphanothece sacrum polysaccharide derivative to the aqueous solution of sodium hyaluronate was changed to 0:100 (mass%). Shrinkage occurred, resulting in an uneven film, and the layer alone was unable to maintain a thin-film structure. The film was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1. Furthermore, for Comparative Example 1, the appearance of the film during formation and the film after film formation is shown in Figure 1.

[0048]

[0049] As shown in Table 1, the films of the present invention are formed using a sulfate-containing polysaccharide (A) and sodium hyaluronate (B), resulting in films with excellent uniformity and high strength. Additionally, as shown in Figure 1, the films containing Aphanothece sacrum polysaccharide and sodium hyaluronate in Examples 1 to 3 had sufficient strength after film formation and were able to maintain their shape well. On the other hand, the film of Comparative Example 1, which did not contain sodium hyaluronate, lacked strength, lost stiffness, and was prone to wrinkling. Furthermore, the film of Comparative Example 2, which did not contain Aphanothece sacrum polysaccharide, was unable to retain moisture due to its insufficient water retention capacity, and was unable to maintain its film structure and shrunk significantly as moisture was lost. Because the films of the present invention can maintain their shape by themselves, they do not require a support and can be applied with a simpler configuration. Furthermore, the base material of the skin-adapted component can be composed only of a sulfate-containing polysaccharide (A) and sodium hyaluronate (B), resulting in a composition with fewer components. Therefore, the film of the present invention is a more simplified and convenient skin adhesive member from the viewpoints of handling, application method, and the structure of the skin adhesive member (component structure and layer structure).

Claims

1. A film containing a polysaccharide (A) having a sulfate group and sodium hyaluronate (B), the polysaccharide (A) having a sulfate group is a polysaccharide obtained from Aphanothece sacrum, The film has a content ratio of the polysaccharide (A) having a sulfate group to the sodium hyaluronate (B) of 80:20 to 20:80 in terms of a mass ratio of [polysaccharide (A) having a sulfate group]:[sodium hyaluronate (B)].

2. 2. The film according to claim 1, wherein the combined mass ratio of the polysaccharide (A) having a sulfate group and the sodium hyaluronate (B) in the film is 70% or more.

3. 2. The film according to claim 1, wherein, when the film contains other components (D) in addition to the polysaccharide (A) having sulfate groups, the sodium hyaluronate (B), and, if contained, water (C), the mass proportion of the other components (D) in the film is 10% or less.

4. The film of claim 1 , wherein the film is used as a skin adhesive member.

5. A step of preparing an aqueous solution (I) containing a polysaccharide (A) having a sulfate group; preparing an aqueous solution (II) containing sodium hyaluronate (B); a step of mixing the aqueous solution (I) and the aqueous solution (II) to obtain a mixed solution (III); and a step of disposing the mixed liquid (III) on a substrate, forming a coating film on the substrate, and then evaporating water in the coating film to dry the coating film, thereby obtaining the film according to any one of claims 1 to 4.