Surface-modified polysaccharide nanomaterials, their dispersions, functional articles, and processing methods for functional articles.

Abstract

To provide a surface-modified polysaccharide nano material that can add functionality while suppressing reduction of mechanical properties of a fabric or the like, and dispersion liquid and functional article thereof.SOLUTION: A polysaccharide nano material is adsorbed onto an article by attractive force interaction to add functionality to the article, where the polysaccharide nano material has a functional group expressing the functionality on a surface thereof, and is constituted such that an average diameter is within the range of 2 nm or more and 100 nm or less and an average length is within the range of 50 nm or more and 1000 nm or less. Polysaccharide is selected from cellulose, chitin and chitosan, and cellulose nanocrystal or chitin nanocrystal is preferable as a polysaccharide nano material, and cellulose nanocrystal is more preferable. It is preferable that the functional group be modified within the range of 0.01 mmol / g or more and 2 mmol / g or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a surface-modified polysaccharide nanomaterial, its dispersion, and a functional article. More specifically, it relates to a surface-modified polysaccharide nanomaterial, its dispersion, and a functional article capable of adding functionality while suppressing a decrease in the mechanical properties of a cloth or the like by adsorbing a polysaccharide nanomaterial modified with a functional group to the cloth or the like.

Background Art

[0002] Studies have been conducted on selectively chemically modifying fiber products such as cloth. As an example, there is an example of applying oxidation (abbreviated as "TEMPO oxidation") using 2,2,6,6-tetramethylpiperidine-1-oxyl radical (abbreviated as "TEMPO") as a catalytic oxidizing agent. Regarding such TEMPO oxidation, chemical modification of cotton cloth has been studied (see Non-Patent Document 1). In this study, it was confirmed that the primary hydroxy group in cellulose was oxidized to a carboxy group by TEMPO oxidation, but the strength of the cotton cloth after TEMPO oxidation decreased.

[0003] In addition, it has been reported that cellulose having a carboxy group introduced by the TEMPO oxidation method undergoes a neutralization reaction with a basic malodorous substance such as ammonia and exhibits deodorizing performance (see Non-Patent Document 2). However, when cloth is directly TEMPO oxidized, it has been reported that there is a drawback of causing a decrease in mechanical properties (see Non-Patent Document 3).

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

[0005] Numerous attempts have been made to modify natural fiber fabrics, but imparting functionalities such as deodorizing and antibacterial properties to natural fiber fabrics (cotton, linen, etc.) has involved direct chemical modification or dyeing of the fabric. This process has resulted in damage to the fabric, stiffness, discoloration, reduced strength, and changes in appearance. Until now, no method has been known for introducing functional groups and obtaining deodorizing and antibacterial properties without damaging the fabric.

[0006] The present invention was made to solve the above problems, and its objective is to provide a surface-modified polysaccharide nanomaterial, a dispersion thereof, and a functional article that can add functionality while suppressing a decrease in the mechanical properties of fabrics and the like. [Means for solving the problem]

[0007] (1) The surface-modified polysaccharide nanomaterial according to the present invention is a polysaccharide nanomaterial that is adsorbed onto an article by attractive interaction and adds functionality to the article, characterized in that the polysaccharide nanomaterial has functional groups that exhibit the functionality on its surface, has an average diameter in the range of 2 nm or more and 100 nm or less, and an average length in the range of 50 nm or more and 1000 nm or less.

[0008] According to this invention, since the functional groups that exhibit functionality are present on the surface, the deterioration of the mechanical properties of the article caused by directly modifying the article surface with functional groups can be suppressed by adsorption to the article through attractive interactions. As a result, the functionality of the functional groups can be imparted to the article while preventing a deterioration in the mechanical properties of the article. Since the average diameter and average length of the surface-modified polysaccharide nanomaterial are within the above range, the degree of the mechanical properties of the article itself does not change significantly, and functionality can be added while maintaining the characteristics of the article.

[0009] In the surface-modified polysaccharide nanomaterial according to the present invention, the polysaccharide is cellulose, chitin, starch, or chitosan, and the polysaccharide nanomaterial is preferably cellulose nanocrystal or chitin nanocrystal, and more preferably cellulose nanocrystal.

[0010] In the surface-modified polysaccharide nanomaterial according to the present invention, the polysaccharide nanomaterial simultaneously imparts multiple functions to the article. According to this invention, for example, as shown in Experiment 3 below, multiple functions (such as colorability and deodorizing properties) can be simultaneously imparted.

[0011] In the surface-modified polysaccharide nanomaterial according to the present invention, it is preferable that the functional group is modified on the surface of the polysaccharide nanomaterial in a range of 0.01 mmol / g or more and 2 mmol / g or less.

[0012] (2) The dispersion according to the present invention is characterized in that the surface-modified polysaccharide nanomaterial according to the present invention is dispersed in a solvent.

[0013] According to this invention, by contacting, coating, printing, or impregnating an article such as a cloth with a dispersion of surface-modified polysaccharide nanomaterials, the material can be easily adsorbed onto the article, thereby imparting functionality to it.

[0014] (3) The functional article according to the present invention is characterized in that the surface-modified polysaccharide nanomaterial according to the present invention is adsorbed onto the article by attractive interaction.

[0015] According to this invention, since the surface-modified polysaccharide nanomaterial is adsorbed to an article such as a cloth by attractive interaction, it is possible to add functionality while suppressing a decrease in the mechanical properties of the article, compared to when the surface of the article is directly modified with functional groups.

[0016] In the functional article according to the present invention, the surface-modified polysaccharide nanomaterial adsorbed on the article is detached from the article, and then a new, unused surface-modified polysaccharide nanomaterial is adsorbed onto the same article.

[0017] Since it is adsorbed on an article such as a surface-modified polysaccharide nanomaterial cloth by gravitational interaction, its desorption is also possible. According to this invention, after the surface-modified polysaccharide nanomaterial is desorbed from the article, a new unused surface-modified polysaccharide nanomaterial is adsorbed on the same article, so that the functionality can be regenerated. As a result, the article can be reused and used repeatedly.

Effect of the Invention

[0018] According to the present invention, it is possible to provide a surface-modified polysaccharide nanomaterial, a dispersion thereof, and a functional article that can add functionality while suppressing a decrease in mechanical properties of cloth or the like.

Brief Description of the Drawings

[0019] [Figure 1] (A) is a schematic diagram showing an example of a surface-modified polysaccharide nanomaterial having a malodor substance-capturing functional group on the surface, and (B) is a schematic diagram showing an example in which the surface-modified polysaccharide nanomaterial adsorbed by gravitational interaction using a cotton cloth captures a malodor substance.

Mode for Carrying Out the Invention

[0020] The surface-modified polysaccharide nanomaterial, the dispersion thereof, and the functional article according to the present invention will be described. The present invention is not limited to the following embodiments and examples as long as it includes the gist described in the present application, and can be modified and applied in various modes.

[0021] [Surface-Modified Polysaccharide Nanomaterial] The surface-modified polysaccharide nanomaterial according to the present invention is a polysaccharide nanomaterial that is adsorbed on an article by gravitational interaction to add functionality to the article, and the polysaccharide nanomaterial has a functional group that exhibits the functionality on the surface, and the average diameter is in the range of 2 nm or more and 100 nm or less, and the average length is in the range of 50 nm or more and 1000 nm or less.

[0022] Because this surface-modified polysaccharide nanomaterial has functional groups on its surface that exhibit functionality, it can be adsorbed onto an article through attractive interactions, thereby suppressing the deterioration of the article's mechanical properties that occurs when the article's surface is directly modified with functional groups, such as in conventional TEMPO oxidation treatment. As a result, the functionality of the functional groups can be imparted to the article while preventing a deterioration in its mechanical properties. Since the average diameter and average length of the surface-modified polysaccharide nanomaterial are within the above range, the degree of the article's inherent mechanical properties does not change significantly, and functionality can be added while maintaining the article's characteristics.

[0023] Each component will be explained in detail.

[0024] (Polysaccharide nanomaterials) In polysaccharide nanomaterials, the polysaccharide can be cellulose, chitin, starch, or chitosan. Preferably, the polysaccharide nanomaterial has an average diameter (average diameter) of 2 nm to 100 nm and an average length of 50 nm to 1000 nm after surface modification. Since the size of the polysaccharide nanomaterial does not change before and after surface modification, the size of the polysaccharide nanomaterial applied in this invention is preferably similar to that of the surface-modified polysaccharide nanomaterial described above, with an average diameter of 2 nm to 100 nm and an average length of 50 nm to 1000 nm. By keeping the average diameter and average length of the polysaccharide nanomaterial within this range, even when surface-modified polysaccharide nanomaterials with similar average diameters and lengths are adsorbed onto an article by attractive interaction, the degree of the article's mechanical properties is not significantly altered, and the texture of the article can be maintained.

[0025] While polysaccharide nanomaterials include cellulose nanofibers (CNF), their average length is 5 μm or more, which differs significantly from the average length of the polysaccharide nanomaterials mentioned above. If such long cellulose nanofibers were surface-modified and adsorbed onto materials such as cloth through attractive interactions, the mechanical properties of the material would change drastically, altering the texture of the material itself.

[0026] The average diameter and average length are measured under magnification using high-resolution scanning electron microscopes such as FE-SEM or transmission electron microscopes. The term "average" is used to account for cases where extremely thick or thin, or extremely long or short, pieces are included. The cross-sectional morphology of the polysaccharide nanomaterials may be circular, angular, or irregular in shape. The "width" and "length" visible under magnification are measured as "diameter" and "length," and the average diameter and average length are evaluated using the average values ​​of n=30 or more.

[0027] Polysaccharide nanomaterials having the above-mentioned average diameter and average length include cellulose nanocrystals (abbreviated as "CNC") and chitin nanocrystals (abbreviated as "ChNC"), and these are preferred, with CNC being even more preferred. CNC is sometimes also called cellulose nanowhisker (abbreviated as "CNW"). As mentioned above, the average length of CNC and ChNC is in the range of 50 to 1000 nm, while the average length of CNF is generally 5 μm or more, showing a significant difference between the two. CNF has a long average length of 5 μm or more, which can get entangled in fibers that make up fabrics, etc., and can greatly change the degree of the mechanical properties of the article itself. However, CNC and ChNC with the above-mentioned average lengths do not get entangled, and do not change the degree of the mechanical properties of the article itself, thus maintaining the texture of the article, and are therefore preferred for application. Furthermore, CNC was developed by the present inventors (Araki, J.; Wada, M.; Kuga, S., Langmuir 2001, 17, 21-27.), and is a crystalline nanoparticle with low specific gravity, colorless and transparent, high activity, low environmental impact, high hardness, and low thermal expansion coefficient. In this application, CNC and ChNC are collectively referred to as CNC (cellulose nanocrystal).

[0028] While surface-modified polysaccharide nanomaterials, obtained by modifying the surface of such polysaccharide nanomaterials with functional groups, exhibit the effects of the present invention, other polysaccharide nanomaterials may also be used, as long as their constituent elements are regulated in order to achieve similar effects (for example, when surface-modified and adsorbed onto an article such as cloth by attractive interaction, the mechanical properties of the article such as cloth do not change significantly). For example, starch, glycogen, pectin, etc., can be used by regulating their size elements.

[0029] (functional group) Functional groups modify the surface of polysaccharide nanomaterials to form surface-modified polysaccharide nanomaterials. Depending on the type of functional group, it acts to exhibit various functionalities. For example, by introducing functional groups that bind to malodorous substances, or functional groups that can support metal ions capable of oxidative decomposition of malodorous substances, into polysaccharide nanomaterials, deodorizing and antibacterial properties can be imparted. Specifically, by introducing acidic carboxyl groups or basic amino groups onto the surface of polysaccharide nanomaterials, deodorizing effects can be imparted through counterion formation with basic malodorous substances (such as ammonia) and acidic malodorous substances (such as acetic acid), respectively. Furthermore, by electrostatically supporting metals such as copper or silver on these functional groups, synergistic improvements in deodorizing and antibacterial properties can be achieved through oxidative decomposition. Chitin is poly-β1-4-N-acetylglucosamine, and commercially available chitin is prepared by treating the shells of crustaceans such as crabs with acid and alkali. In this purification process, some of the acetamide groups of N-acetylglucosamine are deacetylated and converted into free amino groups. Therefore, chitin nanocrystals prepared from commercially available chitin can be used directly as surface-modified polysaccharide nanomaterials. Furthermore, by performing additional alkaline treatment, chitin nanocrystals with an increased proportion of amino groups can be prepared.

[0030] Examples of functional groups include the carboxyl groups and basic amino groups (including secondary and tertiary amino groups) mentioned above, as well as mercapto groups (-SH), isocyanate groups (-NCO), isothiocyanate groups (-NCS), sulfate ester groups (-OSO3H), phosphate ester groups (-OPO4H2), azide groups (-N3), and nitro groups (-NO2). Each of these functional groups exhibits its own unique functionality, thereby giving functionality to the article. While there are no particular limitations on the types of functionality, for example, functional groups that absorb visible light or emit fluorescence can be applied. That is, by reacting a reactive dye with CNC, dye molecules can be bonded to the hydroxyl groups of CNC by forming covalent bonds with compounds that absorb light of specific wavelengths. Furthermore, some functional groups can support metals as described above, so specific functions can be added by supporting metals or other substances according to the purpose.

[0031] Because polysaccharide nanomaterials have a large specific surface area, many functional groups can be added. The amount of such functional group modification varies depending on the type of functional group and the degree of functionality, but it is preferable that the modification is in the range of 0.01 mmol / g or more and 2 mmol / g or less on the surface of the polysaccharide nanomaterial, and more preferably in the range of 0.1 mmol / g or more and 1.8 mmol / g or less.

[0032] Furthermore, surface-modified polysaccharide nanomaterials may be single materials modified with a specific functional group, or composite materials formed by combining materials modified with a specific functional group with materials modified with other specific functional groups. Alternatively, they may be single materials with multiple functional groups modified on their surface. By applying these methods, multi-functional surface-modified polysaccharide nanomaterials can be created, offering potential for a wide range of applications.

[0033] (Goods) Surface-modified polysaccharide nanomaterials are adsorbed onto articles by attractive interactions. Attractive interactions can include adsorption by hydrogen bonding and adsorption by electrostatic interactions. Regarding attractive interactions, adsorption occurs when both a functional group that acts as a hydrogen bond acceptor and a functional group that acts as a hydrogen bond donor are present, such as when a polarized OH bond formed by a hydroxyl group present in the polysaccharide nanomaterial forms a hydrogen bond with an oxygen lone pair present in the functional article. Electrostatic interactions are attractive forces between two fully or partially ionized species with opposite charges. Adsorption occurs by ionizing polysaccharide nanomaterials having -SO4H, -COOH, -NH2 groups, etc., or polysaccharide nanomaterials containing these groups, thereby introducing the functional group responsible for the charge into the article. In addition to hydrogen bonding, adsorption may also occur by van der Waals forces, dipole interactions, π-π interactions, ionic interactions, etc., as long as it can adsorb onto the article and achieve the effects of the present invention. The adsorption mode of attractive interactions can be inferred, as described above, by identifying the functional groups present on the surface of the polysaccharide nanomaterial and identifying the surface state of the article. Furthermore, since the strength of the adsorption is related to the desorption properties of the surface-modified polysaccharide nanomaterial, it is desirable to adjust it based on the intended use of the article on which the surface-modified polysaccharide nanomaterial is adsorbed.

[0034] While the experimental examples described later use cloth (woven fabrics) such as cotton as a representative example of the material, the material is not particularly limited as long as it can be adsorbed by attractive interactions with surface-modified polysaccharide nanomaterials. It can be applied to various fabric products (woven fabrics, knitted fabrics, composite fabrics, nonwoven fabrics, etc.), as well as to materials other than cloth, such as wood, plastics, paper, and films.

[0035] [Dispersion] The dispersion according to the present invention is a suspension in which the surface-modified polysaccharide nanomaterial according to the present invention described above is dispersed in a solvent such as water. By adsorbing this dispersion onto an article by means of contact, coating, printing, or impregnation, the dispersion can be easily adsorbed onto the article and functional properties can be imparted. Adsorption of the surface-modified polysaccharide nanomaterial onto the article may be carried out by means other than those described above, as long as it is possible to adsorb it onto the article. In addition, known viscosity modifiers may be added depending on the adsorption method such as coating or impregnation.

[0036] Surface-modified polysaccharide nanomaterials have hydroxyl groups derived from polysaccharides, thus exhibiting good compatibility with aqueous solvents and excellent water dispersibility. Furthermore, depending on the type of organic solvent, they can also be dispersed in organic solvents. The dispersion amount is preferably determined by determining how much of the surface-modified polysaccharide nanomaterial is adsorbed onto the article to effectively exhibit its functionality. The dispersion may contain only the surface-modified polysaccharide nanomaterial, or it may contain other substances as long as they do not hinder the effects of the present invention.

[0037] Figure 1(A) is a schematic diagram showing an example of a surface-modified polysaccharide nanomaterial with odor-capturing functional groups on its surface, and Figure 1(B) is a schematic diagram showing an example of a surface-modified polysaccharide nanomaterial adsorbed by attractive interactions onto cotton cloth and capturing odor-capturing substances. As shown in Figure 1(B), since the surface-modified polysaccharide nanomaterial is adsorbed onto the cotton cloth by attractive interactions, it has the advantage of not degrading mechanical properties as much as fabrics whose surfaces are surface-modified with functional groups, thus solving the problems of conventional methods.

[0038] [Functional goods] The functional articles according to the present invention are characterized in that the surface-modified polysaccharide nanomaterial according to the present invention is adsorbed onto the article by attractive interactions. In such functional articles, since the surface-modified polysaccharide nanomaterial is adsorbed onto the article, such as a cloth, by attractive interactions, it is possible to add functionality while suppressing the deterioration of the mechanical properties of the article, compared to when the surface of the article is directly modified with functional groups.

[0039] Since the surface-modified polysaccharide nanomaterials adsorbed onto these functional articles are adsorbed through attractive interactions, it is possible to detach the surface-modified polysaccharide nanomaterials adsorbed onto the article. After detaching the surface-modified polysaccharide nanomaterials from the article, unused, new surface-modified polysaccharide nanomaterials can be adsorbed onto the same article. In this way, the functionality of the article can be regenerated, and the article can be reused and used repeatedly.

[0040] For example, if a functional article with added deodorizing properties can capture odor-causing substances, and then the surface-modified polysaccharide nanomaterial that captured the odor-causing substances can be easily detached by washing or external stimulation, the odor-causing substances can be rapidly released. Furthermore, a new surface-modified polysaccharide nanomaterial can be adsorbed onto the article after the detachment of the original surface-modified polysaccharide nanomaterial.

[0041] As mentioned above, functionality can be arbitrarily expressed by the type of functional group and the metals further added to that functional group. Therefore, it is a simple and efficient method that can impart various functions to an item depending on the item. For example, if a surface-modified polysaccharide nanomaterial is used with dye molecules or luminescent phosphodiolus on its surface, it is possible to impart dyeing functionality that does not bleed and is resistant to fading. As with the dye molecule-modified oxidized CNC described in Experiment 3 below, multiple functions (colorability, deodorizing properties, etc.) can be imparted simultaneously. Furthermore, by layering two types of modified surface-modified polysaccharide nanomaterials with different functions, it is possible to exhibit deodorizing performance against multiple malodors.

[0042] Furthermore, as described above, since it is possible to detach the adsorbed surface-modified polysaccharide nanomaterial, multiple captured malodorous substances can be easily washed away along with the surface-modified polysaccharide nanomaterial, resulting in a new fabric processing method that can repeatedly exhibit deodorizing and antibacterial properties.

[0043] As described above, the surface-modified polysaccharide nanomaterial, the dispersion containing the same, and the resulting functional article according to the present invention are such that the surface-modified polysaccharide nanomaterial, which has functional groups on its surface, is adsorbed onto the article by attractive interactions. This suppresses the deterioration of the article's mechanical properties that occurs when the article surface is directly modified with functional groups, such as in conventional TEMPO oxidation treatment. As a result, the functionality of the functional groups can be imparted to the article while preventing a deterioration in its mechanical properties. Since the average diameter and average length of the surface-modified polysaccharide nanomaterial are within the above range, the degree of the article's inherent mechanical properties is not significantly altered, and functionality can be imparted while maintaining the article's characteristics. [Examples]

[0044] The present invention will be further explained with the following experimental examples. However, the present invention is not limited to the experimental examples described below.

[0045] [Experiment 1] (CNC preparation) CNC was prepared based on a method previously reported by the inventors (Araki, J.; Wada, M.; Kuga, S., Langmuir 2001, 17, 21-27). Specifically, first, 50 g of commercially available absorbent cotton (S Cotton, manufactured by Suzuran Co., Ltd.) was added to 500 mL of boiled 2.5 mol / L hydrochloric acid, and hydrolyzed by boiling under reflux for 40 minutes, ensuring that the entire absorbent cotton was thoroughly immersed in the hydrochloric acid. After hydrolysis, the reaction was stopped by adding the same volume of deionized water as the hydrochloric acid, and the filtrate was filtered and washed with deionized water using suction filtration until the filtrate became neutral. 500 mL of deionized water was added to the recovered white solid and ground using a blender for 30 minutes. Then, centrifugation (3000 rpm, 5 minutes) was repeated, and the cloudy supernatant was collected. This operation was repeated until the supernatant became nearly clear. The obtained supernatant water was used as a suspension containing unoxidized CNC (referred to as "unoxidized CNC").

[0046] (Preparation of CNC oxide) Next, TEMPO-oxidized CNC (referred to as "oxidized CNC") was prepared. Specifically, first, 0.2 g of TEMPO (2,2,6,6-tetramethylpiperidine-1-oxy radical) and 2 g of sodium bromide were added to the unoxidized CNC suspension (concentration approximately 1%, 500 g) obtained above and dissolved. Subsequently, sodium hypochlorite aqueous solution was added, calculated so that the solid content weight of sodium hypochlorite was equal to the solid content weight of CNC. The system was stirred for 4 hours while maintaining the pH within the range of 10 to 11 by dropwise addition of 3 mol / L sodium hydroxide aqueous solution. 5 mL of ethanol was added to stop the reaction, and 2.5 mol / L hydrochloric acid aqueous solution was added to lower the pH of the system to 2 or less. The precipitate was centrifuged (3000 rpm, 5 minutes), and the precipitate was repeatedly washed with 0.1 mol / L hydrochloric acid and recovered. The recovered white solid was dialyzed in deionized water for 3 days to obtain an oxidized CNC suspension containing oxidized CNC whose surface was chemically modified with carboxyl groups (-COOH). The size of the oxidized CNC was measured by observing multiple field-of-view regions of the suspension obtained by air drying using a transmission electron microscope. The size in each field-of-view region was measured as an average diameter, with a width in the range of 5-10 nm and an average length in the range of 100-200 nm.

[0047] (Amount of CNC oxide adsorbed onto the fabric and carboxyl group content) First, before adsorbing CNC oxide onto the cloth, the amount of carboxyl groups in CNC oxide alone was quantified by titration. The titration method used was the conductivity titration method previously reported by the inventors (Araki, J.; Wada, M.; Kuga, S., Langmuir 2001, 17, 21-27). Specifically, a 50 mL suspension of CNC oxide (containing 500 mg of CNC oxide and 1 mmol / L of NaCl) was mixed with 2 mL of 0.1 mol / L of HCl, and then 0.1 mol / L of NaOH was added at a rate of 0.1 mL / min for titration. The amount of carboxyl groups in CNC oxide alone was determined from the resulting titration curve. The value obtained was 1.29 mmol / g.

[0048] Next, four types of CNC oxide suspensions with concentrations of 0.5% by mass, 1% by mass, 2% by mass, and 3% by mass were prepared. Approximately 100 mL of each suspension was used to immerse a white cotton cloth (plain weave, 30 cm x 30 cm) for 5 minutes. After that, the cloth was squeezed with a glass rod and air-dried overnight to obtain a cloth with adsorbed CNC oxide (referred to as "CNC oxide cloth"). The amount of carboxyl groups in this CNC oxide cloth was quantified by a dye adsorption method. Specifically, the dye adsorption method involved placing a piece of CNC oxide cloth cut to 3 cm x 3 cm (approximately 0.1 g) into a container, adding approximately 25 g of deionized water, and then adding a TBO (toluidine blue O) solution (5.0 x 10⁻⁶). -4 6 mL of (mol / L) was added. Further deionized water was added to adjust the total weight of the solution to 50 g, and the container was covered and shaken for 2 hours. Then, 0.9 mL of the remaining solution was taken into a test tube and diluted fivefold by adding 3.6 mL of deionized water. The absorbance of the diluted solution at 628 nm was measured using a UV-Vis spectrophotometer to calculate the number of moles of remaining TBO. By subtracting this number of moles of remaining TBO from the initial amount of TBO added, the apparent amount of carboxyl groups on the oxidized CNC cloth was calculated. By dividing the amount of carboxyl groups obtained by this dye adsorption method by the amount of carboxyl groups of CNC alone obtained by the titration method described above, the amount of oxidized CNC adsorbed onto the cloth (mg / g) was determined, as shown in Table 1. For comparison, the same procedure was performed on untreated cloth and unoxidized CNC cloth.

[0049] When comparing the results for oxidized CNC fabric with those for untreated and unoxidized CNC fabric, it was found that oxidized CNC fabric adsorbed approximately 2.5 to 8 times more TBO molecules than untreated and unoxidized CNC fabric. Furthermore, as shown in Table 1, as the concentration of oxidized CNC in the suspension increased, more TBO molecules were adsorbed onto the fabric. Calculating the amount of oxidized CNC adsorbed onto the fabric from these values, it was found that, as shown in Table 1, the amount of oxidized CNC adsorbed onto the fabric increased as the concentration of oxidized CNC in the suspension increased.

[0050] [Table 1]

[0051] [Ammonia gas deodorization test] (Test method) The ammonia gas deodorizing performance was measured using two samples each of oxidized CNC cloth, unoxidized CNC cloth, and untreated cloth used as samples. A gas sampling device with a counter (Gastec Co., Ltd., GV-100S) was used, and gas detection tubes of 3La and 3M (Gastec Co., Ltd.) were used. The 200 ppm ammonia gas was prepared using the following procedure: First, (1) air was placed in a Tedlar bag under vacuum, and an appropriate amount of ammonia water was added. (2) The air inside the Tedlar bag was heated with a dryer to vaporize the ammonia, and then the air inside the Tedlar bag was allowed to circulate for about 1 hour. (3) After about 1 hour, the ammonia concentration inside the Tedlar bag was checked with a gas detection tube. If it was not 200 ppm, the concentration was adjusted with air or ammonia water. (4) After about 2 hours, the ammonia concentration was checked again to confirm that it was 200 ppm.

[0052] The odor reduction measurements were performed using the following procedure: First, (a) the sample, which had been conditioned in a constant temperature and humidity chamber at 20°C and 65%RH, was cut; (b) 0.5g of the sample was placed into the cut end of a 2L Tedlar bag and the opening was sealed with tape; (c) the air inside the Tedlar bag was removed to create a vacuum; (d) pre-prepared ammonia gas was transferred to the Tedlar bag containing the sample; and (e) the moment the gas was introduced was defined as 0 minutes, and the odor inside the Tedlar bag was measured at regular intervals using a gas detection tube. The reduction rate was calculated using the formula: "Reduction rate (%) = ((Initial concentration (200ppm) - Concentration at measurement) / Initial concentration (200ppm)) × 100".

[0053] (Test results) Table 2 shows the results of deodorization tests (ammonia concentration reduction rate) conducted on oxidized CNC fabric treated with 1% by mass oxidized CNC suspension, unoxidized CNC fabric treated with 1% by mass unoxidized CNC suspension, and untreated fabric. The results shown are the average of the two samples. The untreated fabric showed an ammonia reduction rate of approximately 26% after 30 minutes, while the oxidized CNC fabric showed a high deodorization performance with an ammonia reduction rate of approximately 76%. This confirmed that the ammonia adsorption function of the surface-modified carboxyl groups was exhibited on the fabric.

[0054] [Table 2]

[0055] [Mechanical properties] Each fabric sample was conditioned in a constant temperature and humidity chamber at 20°C and 65%RH before measurement. For the average friction coefficient, compressibility, bending stiffness, and bending hysteresis, the characteristics were evaluated using the KES texture measurement system. Tensile strength and elongation were evaluated using a tensile testing machine. The KES texture measurement system is a KES-F system that measures the subjective texture of fabric, while this system attempts to objectively evaluate texture from mechanical properties (Kawabata, Sueo; Sen'i Gakkaishi (Textiles and Industry), 1991, 47, 624-628).

[0056] (Average coefficient of friction) The average coefficient of friction (MIU) is measured by pressing a contact element (friction element) against the surface of a test piece and sliding the test piece horizontally. This measurement relates to the feel and comfort of clothing. Specifically, two samples were prepared for each fabric, and measurements were taken at two locations each in the vertical and horizontal directions for each piece of fabric, with the average value taken. A friction tester (Kato Tech Co., Ltd., KES-SE) was used to measure the friction by moving the sample, placed on a smooth metal surface, horizontally 2 cm at a constant speed of 0.1 cm / second. Ten piano wires were arranged in a row as the contact element, and the load applied to the contact element was 50 gf. The average coefficient of friction (MIU) was measured in this way. The results are shown in Table 3.

[0057] (Compression ratio) Compressibility (EMC) measures the compressive stiffness and recovery from compression of a fabric by applying constant pressure to the surface of a test specimen and allowing it to recover from the compression deformation. This is related to the operability when wearing the garment and the feel when touched by hand. Specifically, two samples of each fabric were prepared, and measurements were taken at two locations on each fabric, with the average taken. A handy compression tester (Kato Tech Co., Ltd., KES-G5) was used, with an area of ​​2 cm². 2The measurement was performed by compressing the sample cloth with a copper indenter having a circular surface. The movement speed of the indenter during the compression-recovery process was 20 μm / sec, and the maximum compressive stress was 50 gf / cm². 2 This measurement produced a compressive stress-transition diagram with the vertical axis representing compressive stress and the horizontal axis representing the distance between the indenters, resulting in a compressive stress of 0.5 gf / cm². 2 The distance between the indenters when pressure was applied was evaluated as the thickness of the sample. The compressibility ratio (EMC) was calculated from the sample thickness before and after compression, and the results are shown in Table 3.

[0058] (Bending properties) Bending properties are measured by alternately applying bending deformation to the front and back surfaces of a test specimen, thereby determining the bending stiffness (B) and bending hysteresis (2HB) of the fabric. The bending properties of the fabric are related to the feel, comfort, and athletic performance of the garment.

[0059] The evaluation methods for bending stiffness (B) and bending hysteresis (2HB) are as described in "Masako Niwa (ed.), Apparel Science, Asakura Shoten, pp. 61-62." Specifically, two samples of each type were prepared, and measurements were taken at two locations each in the warp and weft directions on each piece of fabric, and the average was taken. A bending tester (Kato Tech Co., Ltd., KES-FB2) was used to bend the sample at a constant curvature speed of 0.5 cm. -1 The curvature range K = +2.5 to -2.5 cm such that the front side is convex (positive curvature) and then the back side is convex (negative curvature) at a rate of / second. -1 The sample was subjected to one cycle of bending over a certain period, and the change in bending moment was obtained as an MK diagram with curvature on the horizontal axis. This MK diagram was analyzed using the known method described in the above-mentioned literature, and the bending stiffness (B) was determined by distinguishing between the parameters when the sample was bent so that the front side was convex and the parameters when it was bent so that the back side was convex. The results are also shown in Table 3. For bending hysteresis (2HB), the width of hysteresis at 2HBf:K=0.5 and 2HBb:K=-0.5 was determined using the known method described in the above-mentioned literature, and the average value of 2HBf and 2HBb was defined as the width of hysteresis of the fabric, 2HB(gf·cm / cm)=(2HBf+2HBb) / 2. The results are also shown in Table 3.

[0060] [Table 3]

[0061] (Tensile strength and elongation) Tensile strength is determined from the load at which a test specimen breaks after being subjected to tensile deformation in one direction, and it is closely related to durability. Specifically, two samples were prepared for each type of specimen, and measurements were taken in the longitudinal direction, with the average being calculated. The measurements were performed using the labeled strip method according to JIS L 1096. The maximum point load (N) and maximum point elongation (mm) were measured, and the tensile strength (N / cm) and elongation rate (%) were calculated. A universal testing machine was used, with a tensile speed of 50 mm / min, a test length of 100 mm, and a sample width of 25 mm. The results for tensile strength and elongation rate are shown in Table 4.

[0062] [Table 4]

[0063] (Results of mechanical properties) A comparison of untreated fabric, oxidized CNC fabric, and unoxidized CNC fabric revealed that the mechanical properties of the oxidized CNC fabric did not change significantly compared to the untreated fabric. While the bending stiffness (hardness) increased slightly, there was no significant difference in bending hysteresis (firmness), and the soft texture of the cotton fabric was retained.

[0064] [Experiment 2] The deodorizing properties of oxidized CNC fabric after washing and the re-adsorption of oxidized CNC were investigated. The oxidized CNC fabric prepared in Experiment 1 was washed using the method described below, and the deodorizing properties of the washed oxidized CNC fabric were measured using the same method as in Experiment 1 (sample: 10cm x 10cm, approximately 1.0g). Furthermore, oxidized CNC was re-adsorbed onto the washed oxidized CNC fabric using the method described below, and the deodorizing properties of the re-adsorbed oxidized CNC fabric were measured using the same method as in Experiment 1 (sample: 10cm x 10cm, approximately 1.0g).

[0065] (laundry) As shown in Table 5, the washing process involved using a washing machine to wash the oxidized CNC fabric prepared in Experiment 1 with 300 mL of warm water (38°C ± 2°C), rinsing it three times with an appropriate amount of water (38°C ± 2°C), and then performing a final rinse with 300 mL of warm water (38°C ± 2°C) for 5 minutes. After that, the fabric was dewatered using the washing machine, further removed with paper towels, and then air-dried on a flat surface. This process was repeated four times. This washing method conforms to JIS L1096 Fabric Testing Methods for Woven and Knitted Fabrics (Dimensional Change Test Method E: Washing Machine Method).

[0066] [Table 5]

[0067] (Method for adsorbing re-adsorbed oxidized CNC onto fabric) The sample (10cm x 10cm, approximately 1.0g) washed using the method described above was immersed for 5 minutes in a 1% by mass suspension of CNC oxide used in Experiment 1. Then, it was dewatered using a roller-type dehydrator, and subsequently dried flat overnight at 20°C and 65% RH. At this time, the mass of the sample immediately after dewatering was adjusted to 2.4 to 2.6 times the mass of the dried sample to prepare the test sample.

[0068] (Ammonia gas deodorization test) An ammonia gas deodorization test was conducted using the same test method as in Experiment 1. The results are shown in Table 6. In Table 6, "1 wash" means that the washing procedure shown in Table 5 was performed once, and "4 washes" means that the washing procedure shown in Table 5 was repeated four times. It was found that washing caused the oxidized CNC to fall off and the deodorizing effect to decrease, but the deodorizing effect could be restored by re-adsorbing the oxidized CNC.

[0069] [Table 6]

[0070] The results of Experiment 2 showed that even if oxidized CNC (surface-modified polysaccharide nanomaterial) adsorbed onto the fabric is detached from the fabric due to washing or other reasons, the oxidized CNC can be adsorbed again, allowing the fabric to be reused with restored functionality such as deodorizing properties.

[0071] [Experiment 3] The dye-molecule-modified CNC prepared according to the procedure below was adsorbed onto a white cotton cloth, and its ammonia deodorizing properties were measured using the same method as in Experiment 1 (sample: 10cm x 10cm, approximately 1.0g).

[0072] (Preparation of dye-molecule-modified CNC) Similar to the preparation method described in the "Preparation of Oxidized CNC" section of Experiment 1, oxidized CNC with carboxyl groups introduced to its surface was prepared according to a method previously reported by the inventors (Araki, J.; Wada, M.; Kuga, S., Langmuir 2001, 17, 21-27.). In this preparation method, the solid weight of sodium hypochlorite added during the oxidation reaction was 15% of the solid weight of the starting unoxidized CNC. To the obtained oxidized CNC suspension (1% concentration, 250 mL), 0.75 g of reactive dye (Sumifix Supra Brilliant Red 3BF 150% gran) was added and stirred at room temperature for 5 minutes. Next, 2.5 g of anhydrous sodium sulfate was added and stirred at room temperature for 5 minutes, and then 10 g of anhydrous sodium sulfate was added and stirred for 15 minutes. Next, a 3 mol / L aqueous sodium hydroxide solution was added to adjust the pH of the system to 10-11, and the reaction was carried out by stirring in a 70°C water bath for 45 minutes. After the reaction, the mixture was cooled and dissolved in 30 g of anhydrous magnesium sulfate. The dye-molecule-modified oxidized CNC was then precipitated by centrifugation, followed by two washes using centrifugation with a 0.2 mol / L magnesium sulfate aqueous solution. Water was added to the precipitate to disperse it, and the volume was adjusted to 100 mL. Then, 0.3 mL of soaping solution (N-3, Iwase Shoten Co., Ltd.) was added, and the mixture was heated in a 100°C oil bath for 30 minutes with stirring. After cooling, the mixture was washed twice each using centrifugation with a 0.2 mol / L magnesium sulfate aqueous solution and a 0.1 mol / L hydrochloric acid aqueous solution. Finally, the acid was removed by dialysis to obtain dye-molecule-modified oxidized CNC.

[0073] (Adsorption method) To adsorb dye-molecule-modified oxidized CNC onto white cotton cloth, a 10cm x 10cm piece of white cotton cloth (approximately 1.0g) was immersed in a 1% by mass suspension of dye-molecule-modified oxidized CNC for 5 minutes. The cloth was then dewatered using a roller-type dewatering machine and subsequently dried flat overnight at 20°C and 65% RH. The mass of the sample immediately after dewatering was adjusted to be 2.4 to 2.6 times the mass of the sample after drying. The resulting sample was designated "dye-molecule-modified oxidized CNC cloth." The adsorption of oxidized CNC prepared in Experiment 1 onto white cotton cloth was carried out similarly, and this was designated "oxidized CNC cloth."

[0074] (Ammonia gas deodorization test) Ammonia deodorization tests were conducted on three types of samples: dye-molecule-modified oxidized CNC cloth, oxidized CNC cloth, and untreated cloth (white cotton cloth), using the same method as in Experiment 1 (sample: 10cm x 10cm, approximately 1.0g). The results are shown in Table 7. Table 7 shows the results of the deodorization tests (ammonia concentration reduction rate) performed on the untreated cloth, oxidized CNC cloth, and dye-molecule-modified oxidized CNC. The results for each sample are the average of two samples. The dye-molecule-modified oxidized CNC cloth also possessed ammonia deodorizing properties, demonstrating that coloring and deodorizing properties could be imparted simultaneously.

[0075] [Table 7]

[0076] [Experiment 4] Chitin nanocrystals (ChNC) prepared according to the following procedure were adsorbed onto a white cotton cloth, and their acetic acid deodorizing properties were measured using the method described below.

[0077] (Preparation of chitin nanocrystals) Chitin nanocrystals (ChNCs) were prepared in accordance with the reported literature (Araki, J., Kurihara, M., Biomacromolecules 2015, 16, 379-388). 4 g of commercially available chitin powder (manufactured by Wako Pure Chemical Industries, Ltd.) was added to 100 mL of 3 mol / L hydrochloric acid and boiled for 1.5 hours. After cooling to room temperature, the solution was diluted with deionized water, and the suspended ChNCs were collected by repeated centrifugation. The ChNC suspension, purified by removing acid by dialysis, was immersed in a 5% aqueous solution of polyethylene glycol (molecular weight 20000) while still sealed in the dialysis membrane, concentrated by osmosis, collected, and freeze-dried. The obtained ChNCs were adsorbed onto a cotton cloth using the method described below, and their acetic acid deodorizing properties were measured.

[0078] (ChNC adsorption method) To adsorb ChNC onto cotton cloth, a 30cm x 40cm cotton cloth was immersed in a 1% by mass ChNC suspension for 30 minutes. The cloth was then dewatered using a roller dewatering machine and subsequently dried flat overnight at 20°C and 65% RH. The mass of the sample immediately after dewatering was adjusted to be 2.5 to 2.7 times the mass of the sample after drying. The resulting sample was designated "ChNC-processed cloth."

[0079] (Acetic acid deodorization test) A gas sampling device with a counter (Gastec Co., Ltd., GV-100S) was used, and gas detection tube No. 81 (Gastec Co., Ltd.) was used. The preparation of 100 ppm acetic acid gas was carried out using the following procedure. First, air was introduced into a Tedlar bag under vacuum, an appropriate amount of acetic acid water was added, the air inside the Tedlar bag was heated with a hairdryer to vaporize the acetic acid, and then the air inside the Tedlar bag was circulated. The acetic acid concentration inside the Tedlar bag was checked with a gas detection tube, and if it was not 100 ppm, the concentration was adjusted with air or ammonia water, and then it was confirmed again that the acetic acid concentration was 100 ppm.

[0080] The acetic acid deodorization measurement was performed using the following procedure. First, a sample that had been conditioned in a constant temperature and humidity chamber at 20°C and 65%RH was cut. 0.25g of the sample was placed into the cut end of a 2L Tedlar bag, and the opening was sealed with tape. The air inside the Tedlar bag was removed to create a vacuum. Pre-prepared acetic acid gas was then transferred to the Tedlar bag containing the sample. The moment the gas was introduced was defined as 0 minutes, and the odor inside the Tedlar bag was measured at regular intervals using a gas detection tube. The reduction rate was calculated using the formula: "Reduction rate (%) = ((Initial concentration (100ppm) - Concentration at measurement) / Initial concentration (100ppm)) × 100". The results are shown in Table 8. From the results in Table 8, it was confirmed that the ChNC processed fabric has acetic acid deodorizing properties.

[0081] [Table 8]

Claims

1. A surface-modified polysaccharide nanomaterial that, through attractive interactions, is adsorbed onto articles made of fabric, wood, plastic, paper, or film, thereby adding deodorizing properties to said articles, The surface-modified polysaccharide nanomaterial has functional groups on its surface that bind to basic or acidic malodorous substances, and has an average diameter in the range of 2 nm to 100 nm, and an average length in the range of 50 nm to 1000 nm. The surface-modified polysaccharide nanomaterial is characterized in that it is used to adsorb the basic malodorous substance or the acidic malodorous substance onto the article, detach it from the article after detachment, and then adsorb unused surface-modified polysaccharide nanomaterial onto the article after detachment to regenerate the deodorizing performance of the article.

2. The surface-modified polysaccharide nanomaterial according to claim 1, wherein the surface-modified polysaccharide nanomaterial is a cellulose nanocrystal and has a carboxyl group on its surface that binds to the basic malodorous substance.

3. The surface-modified polysaccharide nanomaterial according to Claim 1, wherein the surface-modified polysaccharide nanomaterial is a chitin nanocrystal and has an amino group on its surface that binds to the acidic malodorous substance.

4. A dispersion characterized in that the surface-modified polysaccharide nanomaterial described in any one of claims 1 to 3 is dispersed in a solvent.

5. A functional article in which a surface-modified polysaccharide nanomaterial is adsorbed to an article by attractive interaction, The article is a cloth product, wood, plastic, paper, or film. The surface-modified polysaccharide nanomaterial has a functional group on its surface that binds to basic or acidic malodorous substances, has an average diameter in the range of 2 nm to 100 nm, and an average length in the range of 50 nm to 1000 nm, and is used in a functional article that is adsorbed onto the article to capture the basic or acidic malodorous substances, detaches from the article after capture, and then adsorbs unused surface-modified polysaccharide nanomaterial onto the article after detachment to regenerate the deodorizing performance of the article.

6. A method for processing a functional article, wherein a surface-modified polysaccharide nanomaterial is adsorbed onto the article by attractive interaction to impart and regenerate deodorizing properties, The article is a cloth product, wood, plastic, paper, or film. A method for processing a functional product, characterized in that the surface-modified polysaccharide nanomaterial has a functional group on its surface that binds to basic or acidic malodorous substances, has an average diameter in the range of 2 nm to 100 nm, and an average length in the range of 50 nm to 1000 nm, and is adsorbed onto an article to capture the basic or acidic malodorous substances, detaches from the article after capture, and repeatedly adsorbs unused surface-modified polysaccharide nanomaterial onto the article after detachment to impart and regenerate the deodorizing performance of the article.

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