Sheet material and method for manufacturing sheet material

Abstract

In sheet materials, the surface resistivity of the substrate is reduced without impairing the texture of the substrate. [Solution] The solution comprises a sheet-like substrate and chitosan and cellulose nanofibers attached to the substrate, wherein both the chitosan content and the cellulose nanofiber content are such that 1 m of the substrate 2 The amount is 0.2g or more per unit, and the total amount of chitosan and cellulose nanofiber is equal to 1 m of base material. 2 This sheet material is characterized by having a content of 1.5g or more and 8.0g or less per unit.

Description

[Technical Field]

[0001] This invention relates to a sheet material and a method for manufacturing a sheet material. [Background technology]

[0002] There is a demand for various antistatic properties in sheet materials such as fabrics, and various inventions have been proposed to meet this need.

[0003] For example, Japanese Patent Publication No. 2019-210578 (Patent Document 1) identifies problems such as repulsion between textiles due to static electricity and clinging to the body, and then discloses a technology for imparting stable electrostatic properties to textiles containing nylon fibers. Specifically, Patent Document 1 discloses an invention in which a polymer is obtained by polymerizing monomers having two or more double bonds capable of radical polymerization onto the surface of nylon fibers.

[0004] Furthermore, Japanese Patent Publication No. 2016-191165 (Patent Document 2) points out that static electricity can cause problems such as malfunctions in nonwoven fabrics used as conveying materials and packaging materials for electrical and electronic components and electrical and electronic equipment, and discloses a polyolefin-based antistatic fiber having excellent durability and water resistance, and a fabric using the same. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2019-210578 [Patent Document 2] Japanese Patent Publication No. 2016-191165 [Overview of the project] [Problems that the invention aims to solve]

[0006] Each invention described in Patent Document 1 and Patent Document 2 adopted a configuration suitable for a specific use in order to achieve the prevention of static electricity in that use. Therefore, these inventions may not be suitable for application to unintended uses. In particular, the application to uses where the texture of the material is emphasized has not been sufficiently studied, and there is room for further study on preventing the generation of static electricity without impairing the texture of the material.

[0007] Therefore, it is desired to realize a sheet material and a method for manufacturing the sheet material that can prevent the generation of static electricity without impairing the texture of the base material.

Means for Solving the Problems

[0008] The sheet material according to the present invention includes a sheet-shaped base material, and chitosan and cellulose nanofibers attached to the base material, and both the content of the chitosan and the content of the cellulose nanofibers are 0.2 g or more per 1 m of the base material 2 and the total of the content of the chitosan and the content of the cellulose nanofibers is 1.5 g or more and 8.0 g or less per 1 m of the base material 2 This is characterized by the above.

[0009] The method for manufacturing a sheet material according to the present invention includes attaching chitosan and cellulose nanofibers to a sheet-shaped base material, and making both the content of the chitosan and the content of the cellulose nanofibers 0.2 g or more per 1 m of the base material 2 and making the total of the content of the chitosan and the content of the cellulose nanofibers 1.5 g or more and 8.0 g or less per 1 m of the base material 2 This is characterized by the above.

[0010] The inventors of the present invention discovered that by treating the substrate with chitosan and cellulose nanofibers in combination, it is possible to achieve a practically sufficient reduction in surface resistivity while reducing the amount of treatment agent compared to other treatments such as using cellulose nanofibers alone, and thus completed the present invention. With the above configuration, the amount of treatment agent can be suppressed compared to conventional technology, so static electricity generation can be prevented while minimizing damage to the texture of the substrate.

[0011] Preferred embodiments of the present invention will be described below. However, the scope of the present invention is not limited by the examples of preferred embodiments described below.

[0012] In one embodiment, the sheet material according to the present invention preferably contains chitosan nanofibers.

[0013] The chitosan in the form of chitosan nanofibers has a finer structure compared to other forms of chitosan, resulting in better dispersibility in dispersion media such as water. Therefore, with the above configuration, it is easier to obtain a sheet material in which chitosan nanofibers are uniformly attached compared to when using other forms of chitosan.

[0014] In one embodiment, the sheet material according to the present invention is preferably manufactured by a manufacturing method that includes the steps of attaching the chitosan to the substrate and further attaching the cellulose nanofibers to the substrate after the chitosan has been attached.

[0015] This configuration makes it easier to reduce the surface resistivity relative to the total content of chitosan and cellulose nanofibers, thus further preventing the generation of static electricity.

[0016] In one embodiment, the sheet material according to the present invention is preferably a fabric in which the base material comprises at least one material selected from the group consisting of polyester, nylon, polypropylene, acrylic, rayon, acetate, silk, wool, and cotton.

[0017] With this configuration, the present invention can be used as a ceiling material installed on the roof of an automobile, a curtain hung inside a room, and so on.

[0018] In one embodiment, the sheet material according to the present invention is preferably a resin sheet in which the base material comprises at least one material selected from the group consisting of polyvinyl chloride, polyethylene, polyester, polypropylene, polyurethane, paper, and rayon.

[0019] With this configuration, the present invention can be used as wallpaper, synthetic leather, and the like.

[0020] The method for manufacturing a sheet material according to the present invention preferably includes the steps of: attaching the chitosan to the substrate; and further attaching the cellulose nanofibers to the substrate after the chitosan has been attached.

[0021] This configuration makes it easier to reduce the surface resistivity relative to the total content of chitosan and cellulose nanofibers, thus further preventing the generation of static electricity.

[0022] Further features and advantages of the present invention will become clearer through the following description of exemplary and non-limiting embodiments, with reference to the drawings. [Brief explanation of the drawing]

[0023] [Figure 1] This is an electron microscope image of the test specimen from Example 5. [Figure 2] This is an electron microscope image of the test specimen from Comparative Example 2. [Figure 3] This shows the results of the bead adhesion test on the test specimen from Example 1. [Figure 4] This shows the results of the bead adhesion test on the test specimen from Example 2. [Figure 5] This shows the results of the bead adhesion test on the specimen of Comparative Example 7. [Figure 6] This shows the results of the bead adhesion test on the specimen of Comparative Example 8. [Modes for carrying out the invention]

[0024] Embodiments of the sheet material and the method for manufacturing the sheet material according to the present invention will be described with reference to the drawings.

[0025] [Definition of Terms] In the specification, claims, drawings, and abstract relating to this application, "sheet material" refers to a component having a shape in which the thickness is thin in proportion to its length and width. Such components include those that are industrially distributed and used under names such as cloth, cloth, textile, woven fabric, knitted fabric, sheet, film, paper, board, and surface material, but these are merely examples.

[0026] [Composition of the sheet material] The sheet material according to this embodiment includes a sheet-shaped substrate and chitosan and cellulose nanofibers attached to the substrate.

[0027] The sheet-like base material characterizes the shape and basic properties (such as mechanical properties) of the sheet material. The base material may, as an example, be a fabric containing at least one material selected from the group consisting of polyester, nylon, polypropylene, acrylic, rayon, acetate, silk, wool, and cotton, with polyester being preferred. When the base material is a fabric, the sheet material can be used as a ceiling material for automobiles, etc. Alternatively, the base material may be a resin sheet (which may also be called a resin film) containing at least one material selected from the group consisting of polyvinyl chloride, polyethylene, polyester, polypropylene, polyurethane, paper, and rayon, with polyvinyl chloride being preferred. When the base material is a resin sheet, the sheet material can be used as wallpaper, etc.

[0028] The sheet material according to this embodiment contains chitosan. Chitosan is a polysaccharide obtained by deacetylating chitin, and may be industrially produced by a method of alkali treatment of chitosan produced from raw materials such as the shells of crustaceans. The chitosan may be unsubstituted or substituted.

[0029] The chitosan preferably contains chitosan nanofibers. Chitosan in the form of chitosan nanofibers has a finer structure compared to other forms of chitosan, resulting in better dispersibility in dispersion media such as water. Therefore, using chitosan nanofibers is advantageous because it makes it easier to obtain a sheet material with uniformly attached chitosan compared to using other forms of chitosan. The characteristics of chitosan nanofibers vary depending on the manufacturing method (defibration treatment method), and those manufactured by physical treatment or chemical treatment are generally available. Furthermore, while the fiber diameter and fiber length of the chitosan nanofibers are not limited, the fiber diameter is preferably 5 nm to 50 nm, and the fiber length is preferably 0.5 μm to 100 μm.

[0030] The sheet material according to this embodiment contains cellulose nanofibers. Cellulose nanofibers are materials obtained by defibrating plant-derived cellulose, and their definition follows, for example, ISO / TS 20477:2023. Cellulose nanofibers have different characteristics depending on the manufacturing method (defibration treatment method), and those manufactured by the modified pulp direct kneading method, those manufactured by physical treatments such as the high-pressure homogenizer method and the ball mill grinding method, and those manufactured by chemical treatments such as the TEMPO oxidation method and the phosphate esterification method are generally available. In the sheet material according to this embodiment, cellulose nanofibers manufactured by any of these manufacturing methods can be used, but those manufactured by chemical treatment are preferred, and those containing sodium are particularly preferred. Cellulose nanofibers containing sodium can be manufactured by the TEMPO oxidation method, etc. Furthermore, the fiber diameter and fiber length of the cellulose nanofibers are not limited, but the fiber diameter is preferably 3 nm to 100 nm, and the fiber length is preferably 0.03 μm to 100 μm.

[0031] Cellulose nanofibers may be unsubstituted or substituted. Examples of substituents when cellulose nanofibers are substituted include, but are not limited to, carboxyl groups, carboxymethyl groups, phosphate groups, phosphite groups, sulfo groups, and xandate groups.

[0032] In the sheet material according to this embodiment, the total content of chitosan and cellulose nanofibers is 1 m of the base material. 2 The amount is between 1.5g and 8.0g per unit. Note that the sheet material according to this embodiment contains chitosan and cellulose nanofibers attached to the substrate; therefore, the chitosan content and cellulose nanofiber content are both calculated per 1 m of substrate. 2 The amount exceeds 0g per unit. The chitosan and cellulose nanofiber content in the sheet material can be determined, for example, by enzymatic hydrolysis.

[0033] The total content of chitosan and cellulose nanofibers is 1.5 g or more per 1 m of the base material 2 When it is 1.5 g or more per 1 m of the base material, the surface resistivity is likely to decrease compared to the base material, and the antistatic effect is likely to be exhibited, which is preferable. When the sheet material exhibits an antistatic effect, for example, it is suitable in that it can suppress the adhesion of fine particles such as dust to the sheet material and suppress the accumulation of static electricity in the sheet material.

[0034] The total content of chitosan and cellulose nanofibers is 1 m of the base material 2 When it is 8.0 g or less per 1 m, it is preferable because a sheet material with a suitable texture is easily obtained. A sheet material with a suitable texture is suitable for application as a fiber product that a person may touch by hand, such as a curtain or a skin material for a seat.

[0035] The content of chitosan and the content of cellulose nanofibers are both 0.2 g or more per 1 m of the base material 2 The content of chitosan and the content of cellulose nanofibers are such that at least one of them is 0.3 g or more per 1 m of the base material 2 It is preferable that both are 0.3 g or more per 1 m of the base material 2 More preferably, both are 0.3 g or more per 1 m of the base material.

[0036] The sheet material according to the present embodiment preferably has a surface resistivity of 1.0×10 12 Ω / sq. or less. When the surface resistivity is within the above range, the sheet material is likely to exhibit an antistatic effect. Here, the surface resistivity refers to a value measured according to JIS K 6911:2006, and is a value measured at an applied voltage of 500 V for a sample conditioned for 24 hours in an environment of 20°C and 65% RH before measurement.

[0037] 〔Method for manufacturing the sheet material〕 The sheet material according to the present embodiment can be manufactured by a manufacturing method including attaching chitosan and cellulose nanofibers to a sheet-like base material. At this time, the total content of chitosan and cellulose nanofibers is 1 m of the base material 2The conditions are adjusted so that the amount per unit is between 1.5g and 8.0g. Examples of the conditions to be adjusted include, but are not limited to, the concentration, contact time and number of contacts with the substrate for the treatment solution containing chitosan, the concentration, contact time and number of contacts with the substrate for the treatment solution containing cellulose nanofibers, the order in which the chitosan and cellulose nanofibers are attached to the substrate (sequentially or simultaneously), and the temperature and humidity when the chitosan and cellulose nanofibers are attached to the substrate.

[0038] The method for attaching chitosan and cellulose nanofibers to the substrate is not particularly limited, but methods such as impregnation, coating, and spraying may be used. Known apparatus for implementing the selected method may be used as appropriate. In the following, the method of impregnating the substrate with a processing solution will be described as an example.

[0039] The order in which chitosan and cellulose nanofibers are attached to the substrate is not limited, but it is preferable to attach the chitosan and then the cellulose nanofibers sequentially to the substrate. That is, in a preferred embodiment, the method for manufacturing the sheet material according to this embodiment includes a first step of attaching chitosan to the substrate, and a second step of further attaching cellulose nanofibers to the substrate after the chitosan has been attached. In the first step, for example, the substrate is impregnated with a treatment solution containing chitosan, and then the substrate is subjected to treatments such as dehydration and drying to obtain a substrate to which chitosan is attached. In the second step, for example, the substrate obtained in the first step (the substrate to which chitosan is attached) is impregnated with a treatment solution containing cellulose nanofibers, and then the substrate is subjected to treatments such as dehydration and drying to obtain a substrate to which chitosan and cellulose nanofibers are attached (i.e., the sheet material according to this embodiment).

[0040] However, there is no preclude from simultaneously attaching chitosan and cellulose nanofibers to the substrate. In this case, for example, the substrate is impregnated with a treatment solution containing both chitosan and cellulose nanofibers, and the substrate is dried to obtain a substrate to which chitosan and cellulose nanofibers are attached (i.e., the sheet material according to this embodiment). Furthermore, there is no preclude from sequentially attaching cellulose nanofibers and then chitosan to the substrate.

[0041] [Consideration of the mechanism of action] The sheet material according to the present invention has a base material of 1 m 2 By containing 1.5g to 8.0g of chitosan and cellulose nanofibers per unit, it exhibits a lower surface resistivity compared to the base material. This is thought to be because the surface of the base material is coated with cellulose nanofibers, forming a hydrophilic film on the surface, which functions as a pathway for electrons.

[0042] Considering the mechanism of action of the present invention in this way, it might seem that chitosan is not essential, and that the reduction in surface resistivity can be achieved by cellulose nanofibers alone. Indeed, it is possible to achieve a surface resistivity of the same degree as the present invention by attaching only cellulose nanofibers to the substrate, but in that case, the amount of cellulose nanofibers attached would be 1 m of substrate. 2 This is significantly larger than the standard of 1.5g to 8.0g per unit area in the present invention. A large amount of treatment agent can impair the texture of the substrate, so when attempting to reduce surface resistivity using only cellulose nanofibers, it was difficult to sufficiently reduce surface resistivity without impairing the texture of the substrate. On the other hand, in the present invention, the amount of treatment agent attached is significantly less than in the case of cellulose nanofibers alone, and while it is at a level that does not easily impair the texture of the substrate, it achieves a reduction in surface resistivity sufficient to prevent static electricity.

[0043] Thus, compared to using cellulose nanofibers alone, the cellulose nanofibers in the sheet material according to the present invention can be said to function efficiently. This is due to the inclusion of chitosan in addition to cellulose nanofibers. Cellulose nanofibers become negatively charged in water due to the carboxyl groups in their molecules. In contrast, chitosan becomes positively charged in water due to the amino groups in its molecules. The presence of both is thought to cause a phenomenon in which cellulose nanofibers adhere to the substrate with high uniformity, using the positive charge of chitosan as a foothold. For example, if the substrate is a fabric containing polyester, it is thought that chitosan adheres to the negatively charged polyester, resulting in a positively charged substrate surface, after which cellulose nanofibers adhere. In this way, the presence of chitosan on the surface of the substrate is thought to improve the wettability of cellulose nanofibers to the substrate, thereby achieving uniform adhesion of cellulose nanofibers. At this time, it is sufficient to have an amount of chitosan that can play a role in regulating the charge on the substrate surface, and it is not necessary for the chitosan itself to form a conductive part. In the present invention, at least one of the chitosan content and the cellulose nanofiber content is equal to 1 m of substrate. 2 The requirement of at least 0.2g per unit is necessary because meeting this condition allows for sufficient adjustment of the charge on the substrate surface.

[0044] Furthermore, cellulose nanofibers uniformly attached to the substrate are expected to form a continuous conductive region. In this case, even if the amount of cellulose nanofibers attached is relatively small, it is thought that the majority of the attached cellulose nanofibers will contribute to the formation of the conductive region. On the other hand, when cellulose nanofibers are attached to the substrate alone, phenomena such as aggregation of cellulose nanofibers may occur, and some of the cellulose nanofibers used may not contribute to the formation of a continuous conductive region. The above considerations were experimentally confirmed. Figure 1 is an electron microscope image of a sample in which chitosan nanofibers and cellulose nanofibers were attached to a polyester fabric (Example 3 described later), and Figure 2 is an electron microscope image of a sample in which only cellulose nanofibers were attached to a polyester fabric (Comparative Example 2 described later). In Figure 1, the surface of the fibers is smooth, and it can be seen that the cellulose nanofibers and chitosan nanofibers are uniformly attached to the polyester fibers. In contrast, in Figure 2, there are irregularities on the surface of the fibers, and it can be seen that the cellulose nanofibers are aggregated. The above observations support the above considerations. In other words, in the state shown in Figure 1, a continuous conductive portion is thought to be formed, while in the state shown in Figure 2, there are places where the conductive portion is interrupted.

[0045] Thus, the mechanism of action of the present invention is explained by a comparative study of the distribution of cellulose nanofibers on the substrate surface when cellulose nanofibers and chitosan are used in combination and when cellulose nanofibers are used alone. In other words, the key to the mechanism of action of the present invention is that by using chitosan, which has the opposite charge to cellulose nanofibers, a uniform conductive portion of cellulose nanofibers is formed on the substrate surface.

[0046] Furthermore, as mentioned above, in order to ensure uniform adhesion of cellulose nanofibers to the substrate, it is preferable that chitosan adheres to the substrate before cellulose nanofibers. However, by adhering the chitosan and then the cellulose nanofibers sequentially, the likelihood of chitosan adhering first can be increased. This is considered to be the reason why, in the present invention, the method of adhering cellulose nanofibers after chitosan has been adhering to the substrate is preferred.

[0047] However, although the mechanism of action has been considered as described above, and some supporting evidence has been obtained from electron microscope images, it has not yet been possible to clearly distinguish and identify sheet materials manufactured by a manufacturing method that includes the steps of attaching chitosan to a substrate and then attaching cellulose nanofibers to the substrate after the chitosan has been attached (a method in which chitosan and cellulose nanofibers are attached sequentially) from sheet materials containing chitosan and cellulose nanofibers manufactured by other methods, based on the material properties, performance characteristics, etc. The reason why such identification is difficult is that the chemical structures of chitosan and cellulose nanofibers are similar, making it difficult to distinguish and observe the two materials when they are attached to a substrate, and it is expected that considerable trial and error will be required to clearly identify the distribution of both materials. On the other hand, it has been experimentally demonstrated by the examples described later that sheet materials manufactured by the method in which chitosan and cellulose nanofibers are attached sequentially represent a particularly advantageous embodiment of the present invention. Based on the above, it can be said that a sheet material manufactured by sequentially attaching chitosan and cellulose nanofibers is an invention that must be identified by its manufacturing method.

[0048] [Examples] The present invention will be further described below with reference to examples. However, the following examples are not limiting to the present invention.

[0049] [Test 1: Test using cloth] (1) Sample The base material is a polyester fabric (weight 158g / m²).2 For the warp and weft threads, both 100d 24f / 2, with a warp and weft density of 65 threads / inch, polyester tropical dye test material (manufactured by Irozome Co., Ltd.) was used. As a treatment agent used to attach chitosan to the substrate, a diluted solution of BiNFi-s(registered trademark)EFo-08002 (aqueous dispersion of chitosan nanofibers (concentration 2%, fiber diameter 20-50nm, degree of polymerization approximately 480)) manufactured by Sugino Machine Co., Ltd. was used. In the following description, this treatment agent will be referred to as "Agent A," and the concentration of chitosan nanofibers in Agent A will be indicated in parentheses. As a treatment agent used to attach cellulose nanofibers to the substrate, a diluted solution of Aronfibro(registered trademark) T-OP100 (aqueous dispersion of cellulose nanofibers (concentration 11%, fiber diameter 3-5nm, fiber length approximately 200nm)) manufactured by Toagosei Co., Ltd. was used. In the following explanation, this treatment agent will be referred to as "Agent B," and the concentration of cellulose nanofibers in Agent B will be indicated in parentheses.

[0050] (2) Preparation of test specimens (Example 1) The substrate was immersed in agent A (1.16% by mass) for 10 seconds, dewatered using a rubber roller, and then dried at 120°C for 5 minutes. This series of operations was repeated twice to obtain a substrate to which chitosan nanofibers were attached. Subsequently, the substrate to which chitosan nanofibers were attached was immersed in agent B (2.36% by mass) for 10 seconds, dewatered using a rubber roller, and then dried at 120°C for 5 minutes to obtain a sheet material to which chitosan nanofibers and cellulose nanofibers were attached. The chitosan nanofiber content in the obtained sheet material was calculated per 1 m of substrate. 2 Each unit contains 3.4g of cellulose nanofiber, and the cellulose nanofiber content is 1m of the base material. 2 Each unit contains 3.4g, and the total content of both is 1m of the base material. 2 The amount was 6.8g per unit. The chitosan nanofiber and cellulose nanofiber content were determined by calculation from the amount of water absorbed and the concentration of the processing solution after immersion, and this was the same for other examples and comparative examples.

[0051] (Example 2) The substrate was immersed in agent A (0.35% by mass) for 10 seconds, dewatered using a rubber roller, and then dried at 120°C for 5 minutes to obtain a substrate with chitosan nanofibers attached. Subsequently, the substrate with chitosan nanofibers attached was immersed in agent B (0.59% by mass) for 10 seconds, dewatered using a rubber roller, and then dried at 120°C for 5 minutes to obtain a sheet material with chitosan nanofibers and cellulose nanofibers attached. The chitosan nanofiber content in the obtained sheet material was per 1 m of substrate. 2 The amount is 0.8g per unit, and the cellulose nanofiber content is 1m of the base material. 2 Each unit contains 0.8g, and the total content of both is 1m of the base material. 2 It was 1.6g per serving.

[0052] (Example 3) The sheet material for Example 3 was obtained in the same manner as in Example 2, except that the chitosan nanofiber concentration of agent A was set to 0.14% by mass and the cellulose nanofiber concentration of agent B was set to 2.36% by mass. In the obtained sheet material, the chitosan nanofiber content was as follows per 1 m of base material. 2 The amount is 0.3g per unit, and the cellulose nanofiber content is 1m of the base material. 2 Each unit contains 3.4g, and the total content of both is 1m of the base material. 2 The amount was 3.7g per sample. Figure 1 shows an electron microscope image of the test specimen from Example 3.

[0053] (Example 4) The substrate was immersed in agent B (2.36% by mass) for 10 seconds, dewatered using a rubber roller, and then dried at 120°C for 5 minutes to obtain a substrate with cellulose nanofibers attached. Subsequently, the substrate with cellulose nanofibers attached was immersed in agent A (1.16% by mass) for 10 seconds, dewatered using a rubber roller, and then dried at 120°C for 5 minutes. This series of operations was repeated twice to obtain sheet materials with chitosan nanofibers and cellulose nanofibers attached. In the obtained sheet materials, the chitosan nanofiber content was per 1 m of substrate. 2 Each unit contains 3.4g of cellulose nanofiber, and the cellulose nanofiber content is 1m of the base material. 2Each unit contains 3.4g, and the total content of both is 1m of the base material. 2 It was 6.8g per serving.

[0054] (Example 5) As a treatment agent for producing the sheet material of Example 5, an aqueous solution containing 0.14% by mass of chitosan nanofibers and 2.36% by mass of cellulose nanofibers was prepared. The substrate was immersed in this treatment agent for 10 seconds, dewatered using a rubber roller, and then dried at 120°C for 5 minutes to obtain a sheet material to which chitosan nanofibers and cellulose nanofibers were attached. In the obtained sheet material, the chitosan nanofiber content was 1 m³ of substrate. 2 The amount is 0.3g per unit, and the cellulose nanofiber content is 1m of the base material. 2 Each unit contains 3.4g, and the total content of both is 1m of the base material. 2 It was 3.7g per serving.

[0055] (Comparative Example 1) The substrate was immersed in agent B (4.72% by mass) for 10 seconds, dewatered using a rubber roller, and then dried at 120°C for 5 minutes. This series of operations was repeated twice to obtain a substrate to which cellulose nanofibers were attached. In the obtained sheet material, the cellulose nanofiber content was 1 m³ of the substrate. 2 It was 13.4g per serving.

[0056] (Comparative Example 2) The substrate was immersed in agent B (2.36% by mass) for 10 seconds, dewatered using a rubber roller, and then dried at 120°C for 5 minutes to obtain a substrate with cellulose nanofibers attached. In the obtained sheet material, the cellulose nanofiber content was 1 m of the substrate. 2 It was 3.4g per serving.

[0057] (Comparative Example 3) A sheet material for Comparative Example 3 was obtained in the same manner as for Comparative Example 2, except that the cellulose nanofiber concentration of agent B was set to 1.18% by mass. In the obtained sheet material, the cellulose nanofiber content was 1 m of the base material. 2 It was 1.7g per serving.

[0058] (Comparative Example 4) The substrate was immersed in agent A (1.16% by mass) for 10 seconds, dewatered using a rubber roller, and then dried at 120°C for 5 minutes. This series of operations was repeated eight times to obtain a substrate to which chitosan nanofibers were attached. In the obtained sheet material, the chitosan nanofiber content was 1 m³ of the substrate. 2 It was 13.4g per serving.

[0059] (Comparative Example 5) The substrate was immersed in agent A (0.69% by mass) for 10 seconds, dewatered using a rubber roller, and then dried at 120°C for 5 minutes to obtain a substrate to which chitosan nanofibers were attached. In the obtained sheet material, the chitosan nanofiber content was 1 m of the substrate. 2 It was 1.7g per serving.

[0060] (Comparative Example 6) A series of operations was performed four times, in which the substrate was immersed in agent A (1.16% by mass) for 10 seconds, dewatered using a rubber roller, and then dried at 120°C for 5 minutes, to obtain a substrate to which chitosan nanofibers were attached. Subsequently, the substrate to which chitosan nanofibers were attached was immersed in agent B (4.72% by mass) for 10 seconds, dewatered using a rubber roller, and then dried at 120°C for 5 minutes to obtain a sheet material to which chitosan nanofibers and cellulose nanofibers were attached. In the obtained sheet material, the chitosan nanofiber content was 1 m³ of the substrate. 2 The amount is 6.7g per unit, and the cellulose nanofiber content is 1m of the base material. 2 Each unit contains 6.7g, and the total content of both is 1m of the base material. 2 It was 13.4g per serving.

[0061] (Comparative Example 7) A sheet material for Comparative Example 7 was obtained in the same manner as in Example 2, except that the chitosan nanofiber concentration of agent A was set to 0.23% by mass and the cellulose nanofiber concentration of agent B was set to 0.47% by mass. In the obtained sheet material, the chitosan nanofiber content was 1 m of the base material. 2 The amount is 0.7g per unit, and the cellulose nanofiber content is 1m of the base material. 2Each unit contains 0.7g, and the total content of both is 1m of the base material. 2 It was 1.4g per serving.

[0062] (Comparative Example 8) A substrate without chitosan nanofibers or cellulose nanofibers attached (untreated substrate) was used as the sample for Comparative Example 8. The chitosan nanofiber content and cellulose nanofiber content were both measured per 1 m of substrate. 2 It was 0g per unit.

[0063] (3) Evaluation of surface resistivity and texture (Measurement of surface resistivity) Surface resistivity was measured for each test specimen in the examples and comparative examples. The measurement method followed JIS K 6911:2006. The samples to be measured were conditioned for 24 hours at 20°C and 65% RH before measurement. The applied voltage during measurement was 500V. For each sample, the surface resistivity was measured at five randomly selected points, and the average value was taken as the measured value for that sample. The measured value was 1.0 × 10⁻⁶. 12 Level A is defined as Ω / sq. or less, and the measured value is 1.0 × 10⁻⁶. 12 Level B was defined as exceeding Ω / sq. The boundary value was 1.0 × 10⁻⁶. 12 Ω / sq. is the surface resistivity commonly required for antistatic materials.

[0064] (Evaluation of texture) From each of the example and comparative example test pieces, evaluation test pieces measuring approximately 210 mm x 297 mm (A4 size as defined in ISO 216:2007) were cut out. For each evaluation test piece of Examples 1-6 and Comparative Examples 1-7, the quality of the texture was determined by sensory evaluation by testers using the evaluation test piece of Comparative Example 8, which was an untreated substrate, as a control. The testers freely tested the evaluation test piece and the control piece with their bare hands, and a level A was assigned if both the stiffness (a feeling of elasticity and fullness) and firmness (a feeling of a stiff fabric being taut) of the evaluation test piece were not significantly inferior to the control. A level B was assigned if either or both of the stiffness and firmness were significantly inferior to the control.

[0065] (result) Table 1 shows the results of the evaluation of surface resistivity and texture for each example and comparative example. In Table 1, "ChNF" represents chitosan nanofiber and "CNF" represents cellulose nanofiber. Both chitosan nanofiber and cellulose nanofiber are included, and at least one of the chitosan nanofiber content and cellulose nanofiber content is 1 m of substrate. 2 The amount is 0.2g or more per unit, and the total amount of chitosan nanofibers and cellulose nanofibers per 1 m of base material is 2 In Examples 1-5, where the amount per sheet was between 1.5g and 8.0g, both the surface resistivity and texture were at level A. However, in Comparative Examples 1-8, which did not meet the above requirements, either the surface resistivity or the texture, or both, were at level B. This result demonstrates that the sheet material according to the present invention can reduce the surface resistivity without impairing the texture of the substrate.

[0066] Table 1: Evaluation of surface resistivity and texture [Table 1]

[0067] (4) Bead adhesion test (Test method) From the test specimens of Example 1, Example 2, Comparative Example 7, and Comparative Example 8, evaluation specimens measuring approximately 140 mm x 220 mm were cut out. A bead container was prepared by placing approximately 5 g of polystyrene beads (approximately 3 mm in diameter) into a polystyrene container (26 cm long x 18 cm wide x 13 cm high). A tester wearing rubber gloves rubbed the evaluation specimen 20 times with a cotton cloth, then placed the evaluation specimen into the bead container and gently lifted it out. The number of beads adhering to the lifted evaluation specimen was counted. The same test was performed a total of three times, and the average number of beads in the three measurements was taken as the measurement value for the specimen.

[0068] (result) The test results for each example are shown in Table 2 and Figures 3 to 6. Table 2 shows the measured values ​​for each example, and Figures 3 to 6 show photographs of the test specimens immediately after being removed from the bead container. As can be seen in Table 2 and Figures 3 to 6, the amount of bead adhesion was significantly less in Examples 1 and 2 compared to Comparative Examples 7 and 8. This result indicates that static electricity was prevented in the test specimens of Examples 1 and 2.

[0069] Table 2: Bead adhesion test [Table 2]

[0070] [Test 2: Test using wallpaper] (1) Sample A vinyl chloride fire-resistant wallpaper (RH-7461, manufactured by Runon Co., Ltd.) was used as the base material. Agents A and B were the same as in Test 1 above.

[0071] (2) Preparation of test specimens (Example 6) For the substrate, add the above-mentioned Agent A (0.67% by mass) to 1 m of the substrate. 2 The agent was applied evenly using a brush or spatula to an application rate of 51g per square meter. The substrate coated with agent A was dried at 120°C for 5 minutes to obtain a substrate with chitosan nanofibers attached. Subsequently, agent B (6.7% by mass) was applied to the substrate with chitosan nanofibers attached, at a rate of 1 m² per square meter of substrate. 2 The B agent was applied uniformly using a brush or spatula to an application rate of 50g per unit area. The substrate coated with agent B was dried at 120°C for 5 minutes to obtain a sheet material to which chitosan nanofibers and cellulose nanofibers were attached. The chitosan nanofiber content in the obtained sheet material was calculated per 1 m of substrate. 2 The amount is 0.3g per unit, and the cellulose nanofiber content is 1m of the base material. 2 Each unit contains 3.4g, and the total content of both is 1m of the base material. 2 The amount was 3.7g per unit. The chitosan nanofiber and cellulose nanofiber content were determined by calculation based on the processing solution concentration and processing amount.

[0072] (Comparative Example 9) A substrate without chitosan nanofibers or cellulose nanofibers attached (untreated substrate) was used as the sample for Comparative Example 9. The chitosan nanofiber content and cellulose nanofiber content were both measured per 1 m of substrate. 2 It was 0g per unit.

[0073] (3) Simulated pollen adhesion test (Test method) 5cm square evaluation specimens were cut from each test specimen in Example 6 and Comparative Example 9. 1g of simulated pollen (lycopodium) and the evaluation specimen were placed in a plastic bag measuring approximately 210mm x 297mm (A4 size as defined in ISO 216:2007), and sealed with air filling about half the capacity. The tester shook the bag by hand for one minute, changing the angle of the bag as needed. The evaluation specimen was removed from the bag and observed visually. Afterwards, the evaluation specimen was attached to a backing sheet, and the simulated pollen was sucked out using a vacuum cleaner. During this process, the vacuum cleaner's suction nozzle was operated so that it passed approximately 5mm above the evaluation specimen over a period of 5 seconds. The evaluation specimen was observed visually again after the suction operation.

[0074] (result) Before contact with the simulated pollen, no clear differences in appearance or texture were observed between the evaluation specimens of Example 6 and Comparative Example 9. Upon observation immediately after removing the evaluation specimens from the bag, both specimens showed yellow discoloration originating from the simulated pollen. However, in the evaluation specimen of Example 6, the yellowing was only recognizable upon close observation, whereas in the evaluation specimen of Comparative Example 9, a clear yellowing was recognizable. Upon observation after vacuuming, both evaluation specimens showed a reduction in yellowing compared to immediately after removal from the bag. However, the yellowing was not noticeable in the evaluation specimen of Example 6 (to a level where stains would not be recognized when considering practical use as wallpaper), whereas in the evaluation specimen of Comparative Example 9, a clearly recognizable yellowing remained. This result indicates that static electricity was prevented in the specimen of Example 6, reducing the adhesion of simulated pollen and making it easier to remove the attached simulated pollen.

[0075] [Other Embodiments] With regard to other configurations, the embodiments disclosed herein are illustrative in all respects, and it should be understood that the scope of the present invention is not limited thereto. Those skilled in the art will readily understand that modifications can be made as appropriate without departing from the spirit of the invention. Therefore, other embodiments modified without departing from the spirit of the invention are naturally included within the scope of the present invention. [Industrial applicability]

[0076] This invention can be applied to sheet materials such as fabrics and wallpaper.

Claims

1. The material comprises a sheet-like substrate and chitosan and cellulose nanofibers attached to the substrate, Both the chitosan content and the cellulose nanofiber content are within the substrate 1 m ２ It is 0.2g or more per unit, and The sum of the chitosan content and the cellulose nanofiber content per m of the substrate ２ A sheet material weighing between 1.5g and 8.0g per sheet.

2. The sheet material according to claim 1, wherein the chitosan comprises chitosan nanofibers.

3. A step of attaching the chitosan to the substrate, The sheet material according to claim 1 or 2, manufactured by a manufacturing method comprising the step of further attaching the cellulose nanofibers to the substrate after the chitosan has been attached.

4. The sheet material according to claim 1 or 2, wherein the base material is a fabric comprising at least one material selected from the group consisting of polyester, nylon, polypropylene, acrylic, rayon, acetate, silk, wool, and cotton.

5. The sheet material according to claim 1 or 2, wherein the base material is a resin sheet comprising at least one material selected from the group consisting of polyvinyl chloride, polyethylene, polyester, polypropylene, polyurethane, paper, and rayon.

6. This involves attaching chitosan and cellulose nanofibers to a sheet-like substrate. The chitosan content and the cellulose nanofiber content are both of the substrate 1 m ２ Each portion should be 0.2g or more, The sum of the chitosan content and the cellulose nanofiber content is calculated as follows: ２ A method for manufacturing a sheet material, wherein the amount per sheet is between 1.5 g and 8.0 g.

7. A step of attaching the chitosan to the substrate, A method for producing a sheet material according to claim 6, comprising the step of further attaching the cellulose nanofibers to the substrate after the chitosan has been attached.

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